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Sample records for nanotube bio-nanocomposites highly

  1. Effect of halloysite content on carboxymethyl cellulose/halloysite nanotube bio-nanocomposite films

    Science.gov (United States)

    Suppiah, Kathiravan; Leng, Teh Pei; Husseinsyah, Salmah; Rahman, Rozyanty; Keat, Yeoh Cheow

    2017-04-01

    Carboxymethyl cellulose/halloysite nanotube (CMC/HNT) bio-nanocomposite films were prepared by solution casting method. The effect of HNT content on tensile properties and morphology were studied. The results showed that the tensile strength of the CMC/HNT bio-nanocomposite films achieved optimum at 10 wt% of HNT content. The elongation at break and modulus of elasticity increased with increasing HNT content. The morphology of CMC/HNT bio-nanocomposite films showed that the poor distribution of HNT filler was observed at 20 wt% of HNT content.

  2. Cytoxicity, dynamic and thermal properties of bio-based rosin-epoxy resin/ castor oil polyurethane/ carbon nanotubes bio-nanocomposites.

    Science.gov (United States)

    Huo, Li; Wang, Dan; Liu, Hongmei; Jia, Pan; Gao, Jungang

    2016-08-01

    In order to prepare bio-nanocomposites with no-cytotoxicity, the rosin-based epoxy resin (MPAER) and castor oil-based polyurethane (COPU) were synthesized and carbon nanotubes (CNTs) was used to enhance the properties of curing MPAER/COPU materials. The curing reaction, dynamic mechanical and thermal properties of this system were characterized by FTIR, NMR, DMA, TG et al. The cytotoxicity of materials is evaluated for HeLa cells using a MTT cell-viability assay. The results showed that COPU can cure MPAER and CNTs can increase effectively the properties of MPAER/COPU nanocomposites. The Tg of MPAER/COPU/CNTs has the highest value when CNTs content is 0.4 wt%, which is 52.4 °C higher than the pure MPAER/COPU. Thermal stability of the nanocomposites is enhanced by the addition of CNTs, the initial decomposition temperature Td5 of the sample No. 0.4 has increased from 284.5 to 305.2 °C, which is 20.7 °C higher than No. 0. The impact strength of the No. 0.4 film is 15 kg cm higher than the pure resin system. The survival rate of HeLa cells to the products is greater than 90% within 48 and 72 h, which demonstrate that this material has excellent biocompatibility and no obvious cytotoxicity for HeLa cells, which may be used in the medical treatment.

  3. Novel fungus-Fe{sub 3}O{sub 4} bio-nanocomposites as high performance adsorbents for the removal of radionuclides

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Congcong [Institute of Plasma Physics, Chinese Academy of Science, P.O. Box 1126, Hefei 230031 (China); University of Science and Technology of China, Hefei 230000 (China); Cheng, Wencai [Institute of Plasma Physics, Chinese Academy of Science, P.O. Box 1126, Hefei 230031 (China); Sun, Yubing, E-mail: sunyb@ipp.ac.cn [Institute of Plasma Physics, Chinese Academy of Science, P.O. Box 1126, Hefei 230031 (China); School for Radiological and Interdisciplinary Sciences (RAD-X), Soochow University and Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, 215123 Suzhou (China); School of Environment and Chemical Engineering, North China Electric Power University, Beijing 102206 (China); Wang, Xiangke, E-mail: xkwang@ipp.ac.cn [Institute of Plasma Physics, Chinese Academy of Science, P.O. Box 1126, Hefei 230031 (China); School for Radiological and Interdisciplinary Sciences (RAD-X), Soochow University and Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, 215123 Suzhou (China); School of Environment and Chemical Engineering, North China Electric Power University, Beijing 102206 (China); Faculty of Engineering, King Abdulaziz University, Jeddah 21589 (Saudi Arabia)

    2015-09-15

    Highlights: • Fungus was used as a template for the assembly of nano-Fe{sub 3}O{sub 4}. • Fungal template directed the nano-Fe{sub 3}O{sub 4} structure from the micro-scale level. • Fungal template enhanced the dispersity and stability of nano-Fe{sub 3}O{sub 4}. • Fungus-Fe{sub 3}O{sub 4} exhibited high sorption capacity for Sr(II), Th(IV) and U(VI). • Fungus-Fe{sub 3}O{sub 4} possessed satisfactory regeneration performance and reusability. - Abstract: The bio-nanocomposites of fungus-Fe{sub 3}O{sub 4} were successfully synthesized using a low-cost self-assembly technique. SEM images showed uniform decoration of nano-Fe{sub 3}O{sub 4} particles on fungus surface. The FTIR analysis indicated that nano-Fe{sub 3}O{sub 4} was combined to the fungus surface by chemical bonds. The sorption ability of fungus-Fe{sub 3}O{sub 4} toward Sr(II), Th(IV) and U(VI) was evaluated by batch techniques. Radionuclide sorption on fungus-Fe{sub 3}O{sub 4} was independent of ionic strength, indicating that inner-sphere surface complexion dominated their sorption. XPS analysis indicated that the inner-sphere radionuclide complexes were formed by mainly bonding with oxygen-containing functional groups (i.e., alcohol, acetal and carboxyl) of fungus-Fe{sub 3}O{sub 4}. The maximum sorption capacities of fungus-Fe{sub 3}O{sub 4} calculated from Langmuir isotherm model were 100.9, 223.9 and 280.8 mg/g for Sr(II) and U(VI) at pH 5.0, and Th(IV) at pH 3.0, respectively, at 303 K. Fungus-Fe{sub 3}O{sub 4} also exhibited excellent regeneration performance for the preconcentration of radionuclides. The calculated thermodynamic parameters showed that the sorption of radionuclides on fungus-Fe{sub 3}O{sub 4} was a spontaneous and endothermic process. The findings herein highlight the novel synthesis method of fungus-Fe{sub 3}O{sub 4} and its high sorption ability for radionuclides.

  4. Development and characterization of a new bio-nanocomposite (bio-NCP) for diagnosis and treatment of breast cancer

    DEFF Research Database (Denmark)

    Martins, Murillo L; Saeki, Margarida J.; Telling, Mark T. F.

    2014-01-01

    Breast cancer is a public health problem throughout the world. Moreover, breast cancer cells have a great affinity for hydroxyapatite, leading to a high occurrence of bone metastasis. In this work we developed a bio-nanocomposite (bio-NCP) in order to use such affinity in the diagnosis...

  5. Effect of type and content of modified montmorillonite on the structure and properties of bio-nanocomposite films based on soy protein isolate and montmorillonite.

    Science.gov (United States)

    Kumar, P; Sandeep, K P; Alavi, S; Truong, V D; Gorga, R E

    2010-06-01

    The nonbiodegradable and nonrenewable nature of plastic packaging has led to a renewed interest in packaging materials based on bio-nanocomposites (biopolymer matrix reinforced with nanoparticles such as layered silicates). Bio-nanocomposite films based on soy protein isolate (SPI) and modified montmorillonite (MMT) were prepared using melt extrusion. The effect of different type (Cloisite 20A and Cloisite 30B) and content (0% to 15%) of modified MMT on the structure (degree of intercalation and exfoliation) and properties (color, mechanical, dynamic mechanical, thermal stability, and water vapor permeability) of SPI-MMT bio-nanocomposite films were investigated. Extrusion of SPI and modified MMTs resulted in bio-nanocomposites with exfoliated structures at lower MMT content (5%). At higher MMT content (15%), the structure of bio-nanocomposites ranged from intercalated for Cloisite 20A to disordered intercalated for Cloisite 30B. At an MMT content of 5%, bio-nanocomposite films based on modified MMTs (Cloisite 20A and Cloisite 30B) had better mechanical (tensile strength and percent elongation at break), dynamic mechanical (glass transition temperature and storage modulus), and water barrier properties as compared to those based on natural MMT (Cloisite Na(+)). Bio-nanocomposite films based on 10% Cloisite 30B had mechanical properties comparable to those of some of the plastics that are currently used in food packaging applications. However, much higher WVP values of these films as compared to those of existing plastics might limit the application of these films to packaging of high moisture foods such as fresh fruits and vegetables.

  6. TiO₂ (rutile) embedded inulin--A versatile bio-nanocomposite for photocatalytic degradation of methylene blue.

    Science.gov (United States)

    Jayanthi Kalaivani, G; Suja, S K

    2016-06-05

    Inulin, a water soluble carbohydrate polymer, was extracted from Allium sativum L. by hot water diffusion method. A novel bio-nanocomposite was prepared by embedding TiO2 (rutile) onto the inulin matrix. The extracted inulin and the prepared bio-nanocomposite were characterized using UV-vis, FT-IR, XRD, SEM, TEM and TGA techniques. The photocatalytic activity of the bio-nanocomposite for the degradation of methylene blue was studied under UV illumination in batch mode experiment and was found to be twice as high as that of pristine TiO2. The kapp for inulin-TiO2 (0.0449 min(-1)) was higher than that for TiO2 (0.0325 min(-1)) which may be due to the synergistic action of inulin and TiO2. The stabilization of photo excited electron suppressed the electron-hole pair recombination thereby inducing the electrons and the holes to participate in the photo reduction and oxidation processes, respectively and enhancing the photocatalytic activity. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Transmission electron microscopy of polyhydroxybutyrate-co-valerate (PHBV)/nanocrystalline cellulose (NCC) bio-nanocomposite prepared using cryo-ultramicrotomy

    Science.gov (United States)

    Ismarul, N. I.; Engku, A. H. E. U.; Siti, N. K.; Tay, K. Y.

    2017-12-01

    Environmental issues on disposal and end-of-life for product made from synthetic petroleum-derived polymers have gained increasing attention from materials scientist to search for new materials with similar physical and mechanical properties but environmental friendly in a way that they are renewable and biodegradable as well. This work is to study the effect of nanocrystalline cellulose in improving the thermal stability of polyhydroxybutyrate-co-valerate biopolymer for high temperature processing of packaging material. 10 % w/w PHBV-NCC bio-nanocomposite feedstock pellet prepared using RONDOL minilab compounder was used as the sample for the preparation of Transmission Electron Microscopy (TEM) sample. RMC Cryo-Ultramicrotomy equipment was used to prepare the ultra-thin slice of the bio-nanocomposite pellet under liquid nitrogen at - 60 °C. Diamond knife was used to slice off about 80-100 nm ultra-thin bio-nanocomposite films and was transferred into the lacey carbon film coated grid using cooled sugar solution. A few drops of phosphotungstic acid was used as negative stain to improve the contrast during the TEM analysis. HITACHI TEM systems was used to obtain the TEM micrograph of PHBV-NCC bio-nanocomposite using 80kV accelerating voltage. A well dispersed NCC in PHBV matrix, ranging from 5 to 25 nm in width was observed.

  8. Cytotoxicity and mechanical behavior of chitin-bentonite clay based polyurethane bio-nanocomposites.

    Science.gov (United States)

    Zia, Khalid Mahmood; Zuber, Mohammad; Barikani, Mehdi; Hussain, Rizwan; Jamil, Tahir; Anjum, Sohail

    2011-12-01

    Chitin based polyurethane bio-nanocomposites (PUBNC) were prepared using chitin, Delite HPS bentonite nanoclay enriched in montmorillonite (MMT), 4,4'-diphenylmethane diisocyanate (MDI) and polycaprolactone polyol CAPA 231 (3000 g/mol(-1)). The prepolymers having different concentration of Delite HPS bentonite nanoclay were extended with 2 moles of chitin. The structures of the resulted polymers were determined by FT-IR technique. The effect of nanoclay contents on mechanical properties and in vitro biocompatibility was investigated. The mechanical properties of the synthesized materials were improved with increase in the Delite HPS bentonite nanoclay contents. Optimum mechanical properties were obtained from the PU bio-nanocomposite samples having 4% Delite HPS bentonite nanoclay. The results revealed that the final PU bio-nanocomposite having 2% Delite HPS bentonite nanoclay contents is ideal contenders for surgical threads with on going investigations into their in vitro biocompatibility, non-toxicity, and mechanical properties. Copyright © 2011 Elsevier B.V. All rights reserved.

  9. Mechanical and optical characterization of bio-nanocomposite from pineapple leaf fiber material for food packaging

    Science.gov (United States)

    Nikmatin, Siti; Rudwiyanti, Jerry R.; Prasetyo, Kurnia W.; Yedi, Dwi A.

    2015-01-01

    The utilization of Bio-nanocomposite material that was derived from pineapple leaf fiber as filler and tapioca starch with plasticizer glycerol as a matrix for food packaging can reduce the use of plastic that usually was made from petroleum materials. It is important to develop and producethis environmental friendly plastic because of limited availability of petroleum nowadays. The process of synthesize and characterization tapioca starch with the plasticizer glycerol bionanocomposites using print method had been conducted. There were 3 samples with different filler concentration variation; 3%, 4% and 5%.The results of mechanical test from each sample showed that bio-nanocomposite with 5% filler concentration was the optimum sample with 4.6320 MPa for tensile strength test and 24.87% for the elongation test. Based on the result of optical test for each sample was gained that along with the increasing of concentration filler would make the absorbance value of the sample became decreased, bio-nanocomposite with 5% filler concentration had several peaks with low absorbance values. The first peak was in 253 nm of wavelength regionwith absorbance of 0.131%, and the second peak was in 343 nmwavelength region and absorbance was 0.087%.

  10. Processing and properties of eco-friendly bio-nanocomposite films filled with cellulose nanocrystals from sugarcane bagasse.

    Science.gov (United States)

    El Achaby, Mounir; El Miri, Nassima; Aboulkas, Adil; Zahouily, Mohamed; Bilal, Essaid; Barakat, Abdellatif; Solhy, Abderrahim

    2017-03-01

    Novel synthesis strategy of eco-friendly bio-nanocomposite films have been exploited using cellulose nanocrystals (CNC) and polyvinyl alcohol/carboxymethyl cellulose (PVA/CMC) blend matrix as a potential in food packaging application. The CNC were extracted from sugarcane bagasse using sulfuric acid hydrolysis, and they were successfully characterized regarding their morphology, size, crystallinity and thermal stability. Thereafter, PVA/CMC-CNC bio-nanocomposite films, at various CNC contents (0.5-10wt%), were fabricated by the solvent casting method, and their properties were investigated. It was found that the addition of 5wt% CNC within a PVA/CMC increased the tensile modulus and strength by 141% and 83% respectively, and the water vapor permeability was reduced by 87%. Additionally, the bio-nanocomposites maintained the same transparency level of the PVA/CMC blend film (transmittance of ∼90% in the visible region), suggesting that the CNC were dispersed at the nanoscale. In these bio-nanocomposites, the adhesion properties and the large number of functional groups that are present in the CNC's surface and the macromolecular chains of the PVA/CMC blend are exploited to improve the interfacial interactions between the CNC and the blend. Consequently, these eco-friendly structured bio-nanocomposites with superior properties are expected to be useful in food packaging applications. Copyright © 2016. Published by Elsevier B.V.

  11. Immobilization of hydrogenase on carbon nanotube polyelectrolytes as heterogeneous catalysts for electrocatalytic interconversion of protons and hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Jiang; Wu, Wen-Jie; Fang, Fang [Fudan University, Department of Chemistry (China); Zorin, Nikolay A. [Russian Academy of Sciences, Institute of Basic Biological Problems (Russian Federation); Chen, Meng; Qian, Dong-Jin, E-mail: djqian@fudan.edu.cn [Fudan University, Department of Chemistry (China)

    2016-08-15

    Immobilization of active enzymes on the surfaces of electrodes and nanomaterials is important in the fields of bioscience, and biotechnology. In this study, we investigated electrocatalytic properties of the interconversion of protons and hydrogen by means of hydrogenase (H{sub 2}ase)-functionalized carbon nanotube polyelectrolyte composites. Multiwalled carbon nanotube polyelectrolytes (MWNT-PEs) were synthesized through a diazonium and an addition reaction with poly(4-vinylpyridine) (P4VP), followed by another addition reaction with either methyl iodide (CH{sub 3}I) or N-methyl-N′-benzyl bromide bipyridinium (VBenBr) to produce MWNT-P4VPMe or MWNT-P4VPBenV polyelectrolytes, respectively. The MWNT-PE@H{sub 2}ase bio-nanocomposites were then prepared by means of MWNT-PEs as substrates to bind with H{sub 2}ase. The redox current density of the MWNT-PE@H{sub 2}ase-modified electrodes increased with a decrease in pH values of the Ar-saturated electrolyte solution owing to the catalytic reduction of protons (H{sub 2} production); further, it increased with the increasing pH values of the H{sub 2}-saturated solution owing to the catalytic oxidation of hydrogen. The reversible color change between blue-colored and colorless viologen (catalyzed by the MWNT-PE@H{sub 2}ase bio-nanocomposites) suggested that they may be developed as nano-biosensors for molecular H{sub 2}. The as-synthesized bio-nanocomposites showed strong long-term stability and high bioactivity.Graphical Abstract.

  12. Preparation and characterization of antibacterial Senegalia (Acacia) senegal/iron–silica bio-nanocomposites

    International Nuclear Information System (INIS)

    Şişmanoğlu, Tuba; Karakuş, Selcan; Birer, Özgür; Soylu, Gülin Selda Pozan; Kolan, Ayşen; Tan, Ezgi; Ürk, Öykü; Akdut, Gizem; Kilislioglu, Ayben

    2015-01-01

    Many studies that research bio-nanocomposites utilize techniques that involve the dispersion of strengthening components like silica, metal and metal oxides through a host biopolymer matrix. The biggest success factor for the bio-nanocomposite is having a smooth integration of organic and inorganic phases. This interattraction between the surfaces of inorganic particles and organic molecules are vital for good dispersion. In this study, a novel biodegradable antibacterial material was developed using gum arabic from Senegalia senegal (stabilizer), silica (structure reinforcer) and zero valent iron particles. Silica particles work to not only strengthen the mechanical properties of the Senegalia senegal but also prevent the accumulation of ZVI nanoparticles due to attraction between hydroxyl groups and FeO. The gum arabic/Fe–SiO 2 bio-nanocomposite showed effective antibacterial property against the Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli. Using Scanning electron microscopy, homogeneous dispersion and uniform particle size was viewed in the biopolymer. X-ray diffraction studies of iron particles organization in Senegalia senegal also showed that the main portion of iron was crystalline and in the form of FeO and Fe 0 . X-ray photoelectron spectroscopy was used to evaluate the chemical composition of the surface but no appreciable peak was measured for the iron before Ar etching. These results suggest that the surface of iron nanoparticles consist mainly of a layer of iron oxides in the form of FeO. Thermal gravimetric analysis was used to determine the thermal stability and absorbed moisture content.

  13. Preparation and characterization of antibacterial Senegalia (Acacia) senegal/iron–silica bio-nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Şişmanoğlu, Tuba; Karakuş, Selcan [Istanbul University, Faculty of Engineering, Department of Chemistry, 34320 Avcilar, Istanbul (Turkey); Birer, Özgür [Koç University, Department of Chemistry, Sarıyer 34450, Istanbul (Turkey); Koç University, KUYTAM Surface Science and Technology Center, Sarıyer 34450, Istanbul (Turkey); Soylu, Gülin Selda Pozan [Istanbul University, Faculty of Engineering, Department of Chemical Engineering, 34320 Avcilar, Istanbul (Turkey); Kolan, Ayşen; Tan, Ezgi; Ürk, Öykü; Akdut, Gizem [Istanbul University, Faculty of Engineering, Department of Chemistry, 34320 Avcilar, Istanbul (Turkey); Kilislioglu, Ayben, E-mail: ayben@istanbul.edu.tr [Istanbul University, Faculty of Engineering, Department of Chemistry, 34320 Avcilar, Istanbul (Turkey)

    2015-11-01

    Many studies that research bio-nanocomposites utilize techniques that involve the dispersion of strengthening components like silica, metal and metal oxides through a host biopolymer matrix. The biggest success factor for the bio-nanocomposite is having a smooth integration of organic and inorganic phases. This interattraction between the surfaces of inorganic particles and organic molecules are vital for good dispersion. In this study, a novel biodegradable antibacterial material was developed using gum arabic from Senegalia senegal (stabilizer), silica (structure reinforcer) and zero valent iron particles. Silica particles work to not only strengthen the mechanical properties of the Senegalia senegal but also prevent the accumulation of ZVI nanoparticles due to attraction between hydroxyl groups and FeO. The gum arabic/Fe–SiO{sub 2} bio-nanocomposite showed effective antibacterial property against the Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli. Using Scanning electron microscopy, homogeneous dispersion and uniform particle size was viewed in the biopolymer. X-ray diffraction studies of iron particles organization in Senegalia senegal also showed that the main portion of iron was crystalline and in the form of FeO and Fe{sup 0}. X-ray photoelectron spectroscopy was used to evaluate the chemical composition of the surface but no appreciable peak was measured for the iron before Ar etching. These results suggest that the surface of iron nanoparticles consist mainly of a layer of iron oxides in the form of FeO. Thermal gravimetric analysis was used to determine the thermal stability and absorbed moisture content.

  14. Novel electrochemical xanthine biosensor based on chitosan–polypyrrole–gold nanoparticles hybrid bio-nanocomposite platform

    Directory of Open Access Journals (Sweden)

    Muamer Dervisevic

    2017-07-01

    Full Text Available The aim of this study was the electrochemical detection of the adenosine-3-phosphate degradation product, xanthine, using a new xanthine biosensor based on a hybrid bio-nanocomposite platform which has been successfully employed in the evaluation of meat freshness. In the design of the amperometric xanthine biosensor, chitosan–polypyrrole–gold nanoparticles fabricated by an in situ chemical synthesis method on a glassy carbon electrode surface was used to enhance electron transfer and to provide good enzyme affinity. Electrochemical studies were carried out by the modified electrode with immobilized xanthine oxidase on it, after which the biosensor was tested to ascertain the optimization parameters. The Biosensor exhibited a very good linear range of 1–200 μM, low detection limit of 0.25 μM, average response time of 8 seconds, and was not prone to significant interference from uric acid, ascorbic acid, glucose, and sodium benzoate. The resulting bio-nanocomposite xanthine biosensor was tested with fish, beef, and chicken real-sample measurements.

  15. Vertically aligned BCN nanotubes with high capacitance.

    Science.gov (United States)

    Iyyamperumal, Eswaramoorthi; Wang, Shuangyin; Dai, Liming

    2012-06-26

    Using a chemical vapor deposition method, we have synthesized vertically aligned BCN nanotubes (VA-BCNs) on a Ni-Fe-coated SiO(2)/Si substrate from a melamine diborate precursor. The effects of pyrolysis conditions on the morphology and thermal property of grown nanotubes, as well as the nanostructure and composition of an individual BCN nanotube, were systematically studied. It was found that nitrogen atoms are bonded to carbons in both graphitic and pyridinic forms and that the resultant VA-BCNs grown at 1000 °C show the highest specific capacitance (321.0 F/g) with an excellent rate capability and high durability with respect to nonaligned BCN (167.3 F/g) and undoped multiwalled carbon nanotubes (117.3 F/g) due to synergetic effects arising from the combined co-doping of B and N in CNTs and the well-aligned nanotube structure.

  16. Effect of gamma ray on magnetic bio-nanocomposite

    International Nuclear Information System (INIS)

    Asadi, Sima; Frounchi, Masoud; Dadbin, Susan

    2016-01-01

    Magnetic polyvinyl alcohol (M-PVA) films were prepared via solution casting filled with surface modified superparamagnetic nanoparticles (M-NPs). The M-NPs were coated with citric acid during synthesis. The chemical interaction between the citric acid and M-NPs was confirmed by Fourier transform infrared spectroscopy (FTIR). The average hydrodynamic diameter of M-NPs was 19.7 nm measured by dynamic light scattering DLS and appeared almost spherical in scanning electron microscopy (SEM). The M-NPs were uniformly dispersed in polyvinyl alcohol (PVA) matrix and showed high optical transparency with good mechanical properties. M-PVA hydrogels were synthesized using gamma irradiation. The characteristic XRD peak of PVA at 19.4° was split after irradiation indicating formation of different crystallite sizes. The M-PVA hydrogel showed higher saturation magnetization compared to un-irradiated M-PVA. Also the presence of M-NPs enhanced the crosslinking of PVA by irradiation. - Highlights: • PVA and Fe 3 O 4 nanocomposite films and hydrogels were prepared. • Gamma-irradiated hydrogels showed high saturation magnetization. • The nanocomposite films had excellent mechanical properties. • Magnetic hydrogels showed high equilibrium water content.

  17. Effect of gamma ray on magnetic bio-nanocomposite

    Energy Technology Data Exchange (ETDEWEB)

    Asadi, Sima [Sharif University of Technology, Department of Chemical and Petroleum Engineering, Tehran (Iran, Islamic Republic of); Frounchi, Masoud, E-mail: frounchi@sharif.edu [Sharif University of Technology, Department of Chemical and Petroleum Engineering, Tehran (Iran, Islamic Republic of); Dadbin, Susan [Radiation Applications Research School, Nuclear Science and Technology Research Institute, Tehran (Iran, Islamic Republic of)

    2016-02-15

    Magnetic polyvinyl alcohol (M-PVA) films were prepared via solution casting filled with surface modified superparamagnetic nanoparticles (M-NPs). The M-NPs were coated with citric acid during synthesis. The chemical interaction between the citric acid and M-NPs was confirmed by Fourier transform infrared spectroscopy (FTIR). The average hydrodynamic diameter of M-NPs was 19.7 nm measured by dynamic light scattering DLS and appeared almost spherical in scanning electron microscopy (SEM). The M-NPs were uniformly dispersed in polyvinyl alcohol (PVA) matrix and showed high optical transparency with good mechanical properties. M-PVA hydrogels were synthesized using gamma irradiation. The characteristic XRD peak of PVA at 19.4° was split after irradiation indicating formation of different crystallite sizes. The M-PVA hydrogel showed higher saturation magnetization compared to un-irradiated M-PVA. Also the presence of M-NPs enhanced the crosslinking of PVA by irradiation. - Highlights: • PVA and Fe{sub 3}O{sub 4} nanocomposite films and hydrogels were prepared. • Gamma-irradiated hydrogels showed high saturation magnetization. • The nanocomposite films had excellent mechanical properties. • Magnetic hydrogels showed high equilibrium water content.

  18. Stiffening mechanisms in amorphous polyamide bio-nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Focke, Walter W. [Institute of Applied Materials, Department of Chemical Engineering, University of Pretoria, Private Bag X20, Hatfield 0028, Pretoria (South Africa); Macheca, Afonso D. [Institute of Applied Materials, Department of Chemical Engineering, University of Pretoria, Private Bag X20, Hatfield 0028, Pretoria (South Africa); Department of Chemical Engineering, Eduardo Mondlane University, P.O. Box 257, Maputo (Mozambique); Benhamida, Aida; Kaci, Mustapha [Laboratoire des Matériaux Polymères Avancés (LMPA), Université de Bejaia 06000 (Algeria)

    2016-05-18

    Dimer fatty acid polyamide nanocomposites based on flake- or needle-shaped nanoparticles were prepared via melt compounding. Transmission electron microscopy showed the presence of both individually dispersed particles and particle agglomerates in the polymer matrix. Dynamic mechanical analysis suggests that three stiffening mechanisms were operating. The reinforcing effect of the high stiffness inorganic filler particles is the primary contributor. Together with the chain confinement effect, that expresses itself in an apparent increase in the glass transition temperature, this provided an adequate rationalization of the stiffness variation below Tg. However, an additional stiffening effect is indicated at temperatures above Tg. The mechanism may involve dynamic network formation based on fluctuating hydrogen bonding interactions between the polymer chains and the filler particles.

  19. Nitrogen in highly crystalline carbon nanotubes

    International Nuclear Information System (INIS)

    Ducati, C; Koziol, K; Stavrinadis, A; Friedrichs, S; Windle, A H; Midgley, P A

    2006-01-01

    Multiwall carbon nanotubes (MWCNTs) with an unprecedented degree of internal order were synthesised by chemical vapour deposition (CVD) adding a nitrogen-containing compound to the hydrocarbon feedstock. Ferrocene was used as the metal catalyst precursor. The remarkable crystallinity of these nanotubes lies both in the isochirality and in the crystallographic register of their walls, as demonstrated by electron diffraction and high resolution electron microscopy experiments. High resolution transmission electron microscopy analysis shows that the walls of the nanotubes consist of truncated stacked cones, instead of perfect cylinders, with a range of apex angles that appears to be related to the nitrogen concentration in the synthesis process. The structure of armchair, zigzag and chiral nanotubes is modelled and discussed in terms of density of topological defects, providing an interesting comparison with our microscopy experiments. A growth mechanism based on the interplay of base- and tip-growth is proposed to account for our experimental observations

  20. Binary PVA bio-nanocomposites containing cellulose nanocrystals extracted from different natural sources: part I.

    Science.gov (United States)

    Fortunati, E; Puglia, D; Luzi, F; Santulli, C; Kenny, J M; Torre, L

    2013-09-12

    PVA bio-nanocomposites reinforced with cellulose nanocrystals (CNC) extracted from commercial microcrystalline cellulose (MCC) and from two types of natural fibres, Phormium tenax and Flax of the Belinka variety, were produced by solvent casting in water. Morphological, thermal, mechanical and transparency properties were studied while the respective efficiency of the extraction process of CNC from the three sources was evaluated. The effect of CNC types and content on PVA properties and water absorption capacity were also evaluated. Natural fibres offered higher levels of extraction efficiency when compared with MCC hydrolysis yield. Thermal analysis proved that CNC promotes the crystallization of the PVA matrix, while improving its plastic response. It was also clarified that all PVA/CNC systems remain transparent due to CNC dispersion at the nanoscale, while being all saturated after the first 18-24h of water absorption. Copyright © 2013 Elsevier Ltd. All rights reserved.

  1. Development and characterization of a new bio-nanocomposite (bio-NCP) for diagnosis and treatment of breast cancer

    Energy Technology Data Exchange (ETDEWEB)

    Martins, Murillo L., E-mail: murillolongo@gmail.com [Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen (Denmark); Instituto de Biociências – Universidade Estadual Paulista – CP 510, 18618-970 Botucatu, SP (Brazil); Saeki, Margarida Juri [Instituto de Biociências – Universidade Estadual Paulista – CP 510, 18618-970 Botucatu, SP (Brazil); Telling, Mark T.F. [ISIS, Rutherford Appleton Laboratory, Chilton, Didcot OX11 OQX (United Kingdom); Department of Materials, University of Oxford, Parks Road, Oxford (United Kingdom); Parra, Joao P.R.L.L. [Instituto de Biociências – Universidade Estadual Paulista – CP 510, 18618-970 Botucatu, SP (Brazil); Landsgesell, Sven [Helmholtz–Zentrum Berlin für Materialien und Energie, Hahn-Meitner Platz 1, D-14109 Berlin (Germany); Smith, Ron I. [ISIS, Rutherford Appleton Laboratory, Chilton, Didcot OX11 OQX (United Kingdom); Bordallo, Heloisa N. [Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen (Denmark)

    2014-01-25

    Highlights: • We synthesized a magnetic bio-NCP with potential to be used against breast cancer. • The magnetic nanoparticles have an inverted spinel structure. • The coating with chitosan does not cause changes to the particle microstructure. • The hydration level of bio-NCP is crucial to the surface modification with apatite. • Bio-NCP with narrow size distribution and high magnetic response was obtained. -- Abstract: Breast cancer is a public health problem throughout the world. Moreover, breast cancer cells have a great affinity for hydroxyapatite, leading to a high occurrence of bone metastasis. In this work we developed a bio-nanocomposite (bio-NCP) in order to use such affinity in the diagnosis and treatment of breast cancer. The bio-NCP consists of magnetic nanoparticles of Mn and Zn ferrite inside a polymeric coating (chitosan) modified with nanocrystals of apatite. The materials were characterized with synchrotron X-ray Powder Diffraction (XPD), Time-of-Flight Neutron Powder Diffraction (NPD), Fourier Transformed Infra-red Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and magnetic measurement with a Physical Property Measurement System (PPMS). We obtained ferrite nanoparticles with a high inversion degree of the spinel structure regarding the Fe and Mn, but with all the Zn in the A site. The coating of such nanoparticles with chitosan had no notable effects to the ferrite microstructure. In addition, the polymeric surface can be easily modified with apatite nanocrystals since the hydration of the bio-NCP during synthesis can be controlled. The resulting bio-NCP presents a spherical shape with a narrow size distribution and high magnetic response at room temperature and is a very promising material for early diagnosis of breast cancer and its treatment.

  2. Simultaneous immobilization of cadmium and lead in contaminated soils by hybrid bio-nanocomposites of fungal hyphae and nano-hydroxyapatites.

    Science.gov (United States)

    Yang, Zhihui; Liang, Lifen; Yang, Weichun; Shi, Wei; Tong, Yunping; Chai, Liyuan; Gao, Shikang; Liao, Qi

    2018-04-01

    Self-aggregation of bulk nano-hydroxyapatites (n-HAPs) undermines their immobilization efficiencies of heavy metals in the contaminated soils. Here, the low-cost, easily obtained, and environment-friendly filamentous fungi have been introduced for the bio-matrices of the hybrid bio-nanocomposites to potentially solve such problem of n-HAPs. According to SEM, TEM, XRD, and FT-IR analyses, n-HAPs were successfully coated onto the fungal hyphae and their self-aggregation was improved. The immobilization efficiencies of diethylene-triamine-pentaacetic acid (DTPA)-extractable Cd and Pb in the contaminated soils by the bio-nanocomposites were individually one to four times of that by n-HAPs or the fungal hyphae. Moreover, the Aspergillus niger-based bio-nanocomposite (ANHP) was superior to the Penicillium Chrysogenum F1-based bio-nanocomposite (PCHP) in immobilization of Cd and Pb in the contaminated soils. In addition, the results of XRD showed that one of the potential mechanisms of metal immobilization by the hybrid bio-nanocomposites was dissolution of n-HAPs followed by precipitation of new metal phosphate minerals. Our results suggest that the hybrid bio-nanocomposite (ANHP) can be recognized as a promising soil amendment candidate for effective remediation on the soils simultaneously contaminated by Cd and Pb.

  3. High frequency conductivity in carbon nanotubes

    Directory of Open Access Journals (Sweden)

    S. S. Abukari

    2012-12-01

    Full Text Available We report on theoretical analysis of high frequency conductivity in carbon nanotubes. Using the kinetic equation with constant relaxation time, an analytical expression for the complex conductivity is obtained. The real part of the complex conductivity is initially negative at zero frequency and become more negative with increasing frequency, until it reaches a resonance minimum at ω ∼ ωB for metallic zigzag CNs and ω < ωB for armchair CNs. This resonance enhancement is indicative for terahertz gain without the formation of current instabilities induced by negative dc conductivity. We noted that due to the high density of states of conduction electrons in metallic zigzag carbon nanotubes and the specific dispersion law inherent in hexagonal crystalline structure result in a uniquely high frequency conductivity than the corresponding values for metallic armchair carbon nanotubes. We suggest that this phenomenon can be used to suppress current instabilities that are normally associated with a negative dc differential conductivity.

  4. Mechanical and solubility properties of bio-nanocomposite film of semi refined kappa carrageenan/ZnO nanoparticles

    Science.gov (United States)

    Saputri, Apriliana Eka; Praseptiangga, Danar; Rochima, Emma; Panatarani, Camellia; Joni, I. Made

    2018-02-01

    The aim of this present work is to develop semi refined kappa carrageenan based bio-nanocomposite film as an alternative to synthetic petroleum based food packaging materials. Among natural polymers, carrageenan is one of the most promising material, since it is a renewable bioresource. The ZnO nanoparticles (0.5%; 1.0%; 1.5% w/w carrageenan) was incorporated into carrageenan polymer to prepare bio-nanocomposite films, where ZnO acts as reinforcement for carrageenan matrix. The mechanical and solubility properties of the prepared films were investigated as a function of ZnO concentration. The results indicated that the addition of ZnO exhibits greater solubility compared to the neat film. The elongation at break is insignificantly different on the films with and without addition ZnO. The tensile strength of the film was highest for the sample with 0.5% ZnO. These mechanical and solubility properties suggest that bio-nanocomposite film of semi refined kappa carrageenan and nanoparticle ZnO can be effectively used as food packaging material.

  5. Fabrication, nanomechanical characterization, and cytocompatibility of gold-reinforced chitosan bio-nanocomposites

    International Nuclear Information System (INIS)

    Patel, Nimitt G.; Kumar, Ajeet; Jayawardana, Veroni N.; Woodworth, Craig D.; Yuya, Philip A.

    2014-01-01

    Chitosan, a naturally derived polymer represents one of the most technologically important classes of active materials with applications in a variety of industrial and biomedical fields. Gold nanoparticles (∼ 32 nm) were synthesized via a citrate reduction method from chloroauric acid and incorporated in Chitosan matrix. Bio-nanocomposite films with varying concentrations of gold nanoparticles were prepared through solution casting process. Uniform distribution of gold nanoparticles was achieved throughout the chitosan matrix and was confirmed with SEM. Synthesis outcomes and prepared nanocomposites were characterized using SEM, TEM, EDX, SAED, UV–vis, XRD, DLS, and Zeta potential for their physical, morphological and structural properties. Nanoscale properties of materials under the influence of temperature were characterized through nanoindentation techniques. From quasi-static nanoindentation, it was observed that hardness and reduced modulus of the nanocomposites were increased significantly in direct proportion to the gold nanoparticle concentration. Gold nanoparticle concentration also showed positive impact on storage modulus and thermal stability of the material. The obtained films were confirmed to be biocompatible by their ability to support growth of human cells in vitro. In summary, the results show enhanced mechanical properties with increasing gold nanoparticle concentration, and provide better understanding of the structure–property relationships of such biocompatible materials for potential biomedical applications. - Highlights: • We fabricated gold reinforced chitosan nanocomposite for biomedical applications. • Gold nanoparticles significantly enhanced nanomechanical properties of chitosan. • Nanocomposite films supported growth of human cells in vitro. • Gold nanoparticles significantly improved cell proliferation on chitosan films

  6. 3D TEM reconstruction and segmentation process of laminar bio-nanocomposites

    International Nuclear Information System (INIS)

    Iturrondobeitia, M.; Okariz, A.; Fernandez-Martinez, R.; Jimbert, P.; Guraya, T.; Ibarretxe, J.

    2015-01-01

    The microstructure of laminar bio-nanocomposites (Poly (lactic acid)(PLA)/clay) depends on the amount of clay platelet opening after integration with the polymer matrix and determines the final properties of the material. Transmission electron microscopy (TEM) technique is the only one that can provide a direct observation of the layer dispersion and the degree of exfoliation. However, the orientation of the clay platelets, which affects the final properties, is practically immeasurable from a single 2D TEM image. This issue can be overcome using transmission electron tomography (ET), a technique that allows the complete 3D characterization of the structure, including the measurement of the orientation of clay platelets, their morphology and their 3D distribution. ET involves a 3D reconstruction of the study volume and a subsequent segmentation of the study object. Currently, accurate segmentation is performed manually, which is inefficient and tedious. The aim of this work is to propose an objective/automated segmentation methodology process of a 3D TEM tomography reconstruction. In this method the segmentation threshold is optimized by minimizing the variation of the dimensions of the segmented objects and matching the segmented V clay (%) and the actual one. The method is first validated using a fictitious set of objects, and then applied on a nanocomposite

  7. Preparation and Properties of Cellulose Laurate (CL/Starch Nanocrystals Acetate (SNA Bio-nanocomposites

    Directory of Open Access Journals (Sweden)

    Feng-Yuan Huang

    2015-07-01

    Full Text Available In the present paper, a series of totally novel bio-nanocomposite films from cellulose laurate (CL and starch nanocrystals acetate (SNA were fabricated, and the properties of nanocomposite films were investigated in detail. SNA was obtained by modifying starch nanocrystals (SNs produced by sulfuric acid hydrolysis of corn starch with acetic anhydride. The favorable dispersity of SNA in chloroform made it ready to convert into nanocomposite films with CL via casting/evaporation method. The transmittance, thermal behavior, mechanical properties, barrier properties and hydrophobicity of CL/SNA nanocomposite films were investigated with UV-vis spectrophotometer, simultaneous thermal analyzer (STA, universal tensile tester/dynamic thermomechanical analysis (DMA, water vapor permeation meter/oxygen permeability tester, and contact angle tester, respectively. The transmittance of nanocomposite films decreased with the increase of SNA content. Thermogravimetric analysis (TGA results showed that the introduction of SNA into CL matrix did not severely decrease the thermal behavior of CL/SNA nanocomposites. Moreover, non-linear and linear mechanical analysis reflected the enhancement of SNA. At lower contents of SNA (<5.0 wt%, the values of Young’s modulus, tensile strength and the elongation at break of nanocomposite films were comparable with those of neat CL. However, with the increase of SNA, the Young’s modulus and tensile strength were improved significantly and were accompanied by the decreased elongation at break. The water vapor permeability (WVP and oxygen permeability (PO2 of CL/SNA nanocomposite films were significantly improved by the addition of SNA.

  8. Carbon nanotubes for high-performance logic

    OpenAIRE

    Chen, Zhihong; Wong, H.S. Phillip; Mitra, Subhasish; Bol, Aggeth; Peng, Lianmao; Hills, Gage; Thissen, Nick

    2014-01-01

    Single-wall carbon nanotubes (CNTs) were discovered in 1993 and have been an area of intense research since then. They offer the right dimensions to explore material science and physical chemistry at the nanoscale and are the perfect system to study low-dimensional physics and transport. In the past decade, more attention has been shifted toward making use of this unique nanomaterial in real-world applications. In this article, we focus on potential applications of CNTs in the high-performanc...

  9. Fabrication of high thermal conductivity arrays of carbon nanotubes and their composites

    Science.gov (United States)

    Geohegan, David B [Knoxville, TN; Ivanov, Ilya N [Knoxville, TN; Puretzky, Alexander A [Knoxville, TN

    2010-07-27

    Methods and apparatus are described for fabrication of high thermal conductivity arrays of carbon nanotubes and their composites. A composition includes a vertically aligned nanotube array including a plurality of nanotubes characterized by a property across substantially all of the vertically aligned nanotube array. A method includes depositing a vertically aligned nanotube array that includes a plurality of nanotubes; and controlling a deposition rate of the vertically aligned nanotubes array as a function of an in situ monitored property of the plurality of nanotubes.

  10. High pressure synthesis of amorphous TiO2 nanotubes

    Directory of Open Access Journals (Sweden)

    Quanjun Li

    2015-09-01

    Full Text Available Amorphous TiO2 nanotubes with diameters of 8-10 nm and length of several nanometers were synthesized by high pressure treatment of anatase TiO2 nanotubes. The structural phase transitions of anatase TiO2 nanotubes were investigated by using in-situ high-pressure synchrotron X-ray diffraction (XRD method. The starting anatase structure is stable up to ∼20GPa, and transforms into a high-density amorphous (HDA form at higher pressure. Pressure-modified high- to low-density transition was observed in the amorphous form upon decompression. The pressure-induced amorphization and polyamorphism are in good agreement with the previous results in ultrafine TiO2 nanoparticles and nanoribbons. The relationship between the LDA form and α-PbO2 phase was revealed by high-resolution transmission electron microscopy (HRTEM study. In addition, the bulk modulus (B0 = 158 GPa of the anatase TiO2 nanotubes is smaller than those of the corresponding bulks and nanoparticles (180-240 GPa. We suggest that the unique open-ended nanotube morphology and nanosize play important roles in the high pressure phase transition of TiO2 nanotubes.

  11. High Performances of Artificial Nacre-Like Graphene Oxide-Carrageenan Bio-Nanocomposite Films.

    Science.gov (United States)

    Zhu, Wenkun; Chen, Tao; Li, Yi; Lei, Jia; Chen, Xin; Yao, Weitang; Duan, Tao

    2017-05-16

    This study was inspired by the unique multi-scale and multi-level 'brick-and-mortar' (B&M) structure of nacre layers. We prepared the B&M, environmentally-friendly graphene oxide-carrageenan (GO-Car) nanocomposite films using the following steps. A natural polyhydroxy polymer, carrageenan, was absorbed on the surface of monolayer GO nanosheets through hydrogen-bond interactions. Following this, a GO-Car hybridized film was produced through a natural drying process. We conducted structural characterization in addition to analyzing mechanical properties and cytotoxicity of the films. Scanning electron microscope (SEM) and X-ray diffraction (XRD) analyses showed that the nanocomposite films had a similar morphology and structure to nacre. Furthermore, the results from Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and Thermogravimetric (TG/DTG) were used to explain the GO-Car interaction. Analysis from static mechanical testers showed that GO-Car had enhanced Young's modulus, maximum tensile strength and breaking elongation compared to pure GO. The GO-Car nanocomposite films, containing 5% wt. of Car, was able to reach a tensile strength of 117 MPa. The biocompatibility was demonstrated using a RAW264.7 cell test, with no significant alteration found in cellular morphology and cytotoxicity. The preparation process for GO-Car films is simple and requires little time, with GO-Car films also having favorable biocompatibility and mechanical properties. These advantages make GO-Car nanocomposite films promising materials in replacing traditional petroleum-based plastics and tissue engineering-oriented support materials.

  12. High Performances of Artificial Nacre-Like Graphene Oxide-Carrageenan Bio-Nanocomposite Films

    Directory of Open Access Journals (Sweden)

    Wenkun Zhu

    2017-05-01

    Full Text Available This study was inspired by the unique multi-scale and multi-level ‘brick-and-mortar’ (B&M structure of nacre layers. We prepared the B&M, environmentally-friendly graphene oxide-carrageenan (GO-Car nanocomposite films using the following steps. A natural polyhydroxy polymer, carrageenan, was absorbed on the surface of monolayer GO nanosheets through hydrogen-bond interactions. Following this, a GO-Car hybridized film was produced through a natural drying process. We conducted structural characterization in addition to analyzing mechanical properties and cytotoxicity of the films. Scanning electron microscope (SEM and X-ray diffraction (XRD analyses showed that the nanocomposite films had a similar morphology and structure to nacre. Furthermore, the results from Fourier transform infrared spectroscopy (FT-IR, Raman spectroscopy, X-ray photoelectron spectroscopy (XPS and Thermogravimetric (TG/DTG were used to explain the GO-Car interaction. Analysis from static mechanical testers showed that GO-Car had enhanced Young’s modulus, maximum tensile strength and breaking elongation compared to pure GO. The GO-Car nanocomposite films, containing 5% wt. of Car, was able to reach a tensile strength of 117 MPa. The biocompatibility was demonstrated using a RAW264.7 cell test, with no significant alteration found in cellular morphology and cytotoxicity. The preparation process for GO-Car films is simple and requires little time, with GO-Car films also having favorable biocompatibility and mechanical properties. These advantages make GO-Car nanocomposite films promising materials in replacing traditional petroleum-based plastics and tissue engineering-oriented support materials.

  13. Development of photo-modified starch/kefiran/TiO2 bio-nanocomposite as an environmentally-friendly food packaging material.

    Science.gov (United States)

    Goudarzi, Vahid; Shahabi-Ghahfarrokhi, Iman

    2018-05-21

    This paper reports on an experiment in which starch/kefiran/TiO 2 (SKT)-based bio-nanocomposite films were developed and modified by photo-chemical reaction. In so doing, film-forming solutions were exposed to ultraviolet A (UV-A) for different times (1, 6, and 12 h). The obtained results indicated that increasing UV-A exposure time brought about an increase (≈14.9%) in the tensile strength of bio-nanocomposites. However, elongation at break and Young's modulus of irradiated film specimen decreased (≈32%, ≈12%, respectively) by increasing UV-A exposure time, and the moisture-sensitive parameters of specimen decreased using UV-A irradiation. According to the results, the functional properties of irradiated bio-nanocomposite are depended on the ratio of cross-linkages between polymer chains and the potentially produced mono and disaccharide by UV-A. Copyright © 2018. Published by Elsevier B.V.

  14. High efficiency carbon nanotube thread antennas

    Science.gov (United States)

    Amram Bengio, E.; Senic, Damir; Taylor, Lauren W.; Tsentalovich, Dmitri E.; Chen, Peiyu; Holloway, Christopher L.; Babakhani, Aydin; Long, Christian J.; Novotny, David R.; Booth, James C.; Orloff, Nathan D.; Pasquali, Matteo

    2017-10-01

    Although previous research has explored the underlying theory of high-frequency behavior of carbon nanotubes (CNTs) and CNT bundles for antennas, there is a gap in the literature for direct experimental measurements of radiation efficiency. These measurements are crucial for any practical application of CNT materials in wireless communication. In this letter, we report a measurement technique to accurately characterize the radiation efficiency of λ/4 monopole antennas made from the CNT thread. We measure the highest absolute values of radiation efficiency for CNT antennas of any type, matching that of copper wire. To capture the weight savings, we propose a specific radiation efficiency metric and show that these CNT antennas exceed copper's performance by over an order of magnitude at 1 GHz and 2.4 GHz. We also report direct experimental observation that, contrary to metals, the radiation efficiency of the CNT thread improves significantly at higher frequencies. These results pave the way for practical applications of CNT thread antennas, particularly in the aerospace and wearable electronics industries where weight saving is a priority.

  15. Fabrication of mesoporous and high specific surface area lanthanum carbide-carbon nanotube composites

    International Nuclear Information System (INIS)

    Biasetto, L.; Carturan, S.; Maggioni, G.; Zanonato, P.; Bernardo, P. Di; Colombo, P.; Andrighetto, A.; Prete, G.

    2009-01-01

    Mesoporous lanthanum carbide-carbon nanotube composites were produced by means of carbothermal reaction of lanthanum oxide, graphite and multi-walled carbon nanotube mixtures under high vacuum. Residual gas analysis revealed the higher reactivity of lanthanum oxide towards carbon nanotubes compared to graphite. After sintering, the composites revealed a specific surface area increasing with the amount of carbon nanotubes introduced. The meso-porosity of carbon nanotubes was maintained after thermal treatment.

  16. Carbon nanotubes for high-performance logic

    NARCIS (Netherlands)

    Chen, Zhihong; Philip Wong, H.-S.; Mitra, S.; Bol, A.A.; Peng, Lianmao; Hills, Gage; Thissen, N.F.W.

    2014-01-01

    Single-wall carbon nanotubes (CNTs) were discovered in 1993 and have been an area of intense research since then. They offer the right dimensions to explore material science and physical chemistry at the nanoscale and are the perfect system to study low-dimensional physics and transport. In the past

  17. Confinement of hydrogen at high pressure in carbon nanotubes

    Science.gov (United States)

    Lassila, David H [Aptos, CA; Bonner, Brian P [Livermore, CA

    2011-12-13

    A high pressure hydrogen confinement apparatus according to one embodiment includes carbon nanotubes capped at one or both ends thereof with a hydrogen-permeable membrane to enable the high pressure confinement of hydrogen and release of the hydrogen therethrough. A hydrogen confinement apparatus according to another embodiment includes an array of multi-walled carbon nanotubes each having first and second ends, the second ends being capped with palladium (Pd) to enable the high pressure confinement of hydrogen and release of the hydrogen therethrough as a function of palladium temperature, wherein the array of carbon nanotubes is capable of storing hydrogen gas at a pressure of at least 1 GPa for greater than 24 hours. Additional apparatuses and methods are also presented.

  18. Piezoelectric Nanotube Array for Broadband High-Frequency Ultrasonic Transducer.

    Science.gov (United States)

    Liew, Weng Heng; Yao, Kui; Chen, Shuting; Tay, Francis Eng Hock

    2018-03-01

    Piezoelectric materials are vital in determining ultrasonic transducer and imaging performance as they offer the function for conversion between mechanical and electrical energy. Ultrasonic transducers with high-frequency operation suffer from performance degradation and fabrication difficulty of the demanded piezoelectric materials. Hence, we propose 1-D polymeric piezoelectric nanostructure with controlled nanoscale features to overcome the technical limitations of high-frequency ultrasonic transducers. For the first time, we demonstrate the integration of a well-aligned piezoelectric nanotube array to produce a high-frequency ultrasonic transducer with outstanding performance. We find that nanoconfinement-induced polarization orientation and unique nanotube structure lead to significantly improved piezoelectric and ultrasonic transducing performance over the conventional piezoelectric thin film. A large bandwidth, 126% (-6 dB), is achieved at high center frequency, 108 MHz. Transmission sensitivity of nanotube array is found to be 46% higher than that of the monolithic thin film transducer attributed to the improved electromechanical coupling effectiveness and impedance match. We further demonstrate high-resolution scanning, ultrasonic imaging, and photoacoustic imaging using the obtained nanotube array transducers, which is valuable for biomedical imaging applications in the future.

  19. High-performance carbon nanotube-reinforced bioplastic

    CSIR Research Space (South Africa)

    Ramontja, J

    2009-12-01

    Full Text Available -1 High-Performance Carbon Nanotube-Reinforced Bioplastic 1. James Ramontja1,2, 2. Suprakas Sinha Ray1,*, 3. Sreejarani K. Pillai1, 4. Adriaan S. Luyt2 1. 1 DST/CSIR Nanotechnology Innovation Centre, National Centre for Nano-Structured Materials...

  20. The unexpected stability of multiwall nanotubes under high pressure and shear deformation

    International Nuclear Information System (INIS)

    Pashkin, E. Y.; Pankov, A. M.; Kulnitskiy, B. A.; Mordkovich, V. Z.; Perezhogin, I. A.; Karaeva, A. R.; Popov, M. Y.; Sorokin, P. B.; Blank, V. D.

    2016-01-01

    The behavior of multiwall carbon nanotubes under a high pressure (up to 55 GPa) combined with shear deformation was studied by experimental and theoretical methods. The unexpectedly high stability of the nanotubes' structure under high stresses was observed. After the pressure was released, we observed that the nanotubes had restored their shapes. Atomistic simulations show that the hydrostatic and shear stresses affect the nanotubes' structure in a different way. It was found that the shear stress load in the multiwall nanotubes' outer walls can induce their connection and formation of an amorphized sp"3-hybridized region but internal core keeps the tubular structure.

  1. The unexpected stability of multiwall nanotubes under high pressure and shear deformation

    Energy Technology Data Exchange (ETDEWEB)

    Pashkin, E. Y.; Pankov, A. M.; Kulnitskiy, B. A.; Mordkovich, V. Z. [Technological Institute for Superhard and Novel Carbon Materials, 7a Centralnaya Street, Troitsk, Moscow 142190 (Russian Federation); Moscow Institute of Physics and Technology, 9 Institutsky Lane, Dolgoprudny 141700 (Russian Federation); Perezhogin, I. A. [Technological Institute for Superhard and Novel Carbon Materials, 7a Centralnaya Street, Troitsk, Moscow 142190 (Russian Federation); Lomonosov Moscow State University, Leninskie Gory, Moscow 119991 (Russian Federation); Karaeva, A. R. [Technological Institute for Superhard and Novel Carbon Materials, 7a Centralnaya Street, Troitsk, Moscow 142190 (Russian Federation); Popov, M. Y.; Sorokin, P. B.; Blank, V. D. [Technological Institute for Superhard and Novel Carbon Materials, 7a Centralnaya Street, Troitsk, Moscow 142190 (Russian Federation); Moscow Institute of Physics and Technology, 9 Institutsky Lane, Dolgoprudny 141700 (Russian Federation); National University of Science and Technology MISiS, 4 Leninskiy Prospekt, Moscow 119049 (Russian Federation)

    2016-08-22

    The behavior of multiwall carbon nanotubes under a high pressure (up to 55 GPa) combined with shear deformation was studied by experimental and theoretical methods. The unexpectedly high stability of the nanotubes' structure under high stresses was observed. After the pressure was released, we observed that the nanotubes had restored their shapes. Atomistic simulations show that the hydrostatic and shear stresses affect the nanotubes' structure in a different way. It was found that the shear stress load in the multiwall nanotubes' outer walls can induce their connection and formation of an amorphized sp{sup 3}-hybridized region but internal core keeps the tubular structure.

  2. Morphological Investigation into Starch Bio-Nanocomposites via Synchrotron Radiation and Differential Scanning Calorimetry

    Directory of Open Access Journals (Sweden)

    Huihua Liu

    2011-01-01

    Full Text Available We studied a hydrophilic, plasticized bionanocomposite system involving sorbitol plasticizer, amylose biopolymer, and montmorillonite (MMT for the presence of competitive interactions among them at different moisture content. Synchrotron analysis via small angle X-ray scattering (SAXS and thermal analysis using differential scanning calorimetry (DSC were performed to understand crystalline growth and the distribution of crystalline domains within the samples. The SAXS diffraction patterns showed reduced interhelix spacing in the amylose network indicating strong amylose-sorbitol interactions. Depending on the sorbitol and MMT concentration, these interactions also affected the free moisture content and crystalline domains. Domains of around 95 Å and 312 Å were found in the low-moisture-content samples as compared to a single domain of 95 Å in the high-moisture-content samples. DSC measurements confirmed that the MMT increased the onset and the melting temperature of nanocomposites. Moreover, the results showed that the ternary interactions among sorbitol-amylose-MMT supported the crystalline heterogeneity through secondary nucleation.

  3. Physicochemical and antifungal properties of bio-nanocomposite film based on gelatin-chitin nanoparticles.

    Science.gov (United States)

    Sahraee, Samar; Milani, Jafar M; Ghanbarzadeh, Babak; Hamishehkar, Hamed

    2017-04-01

    The gelatin-based nanocomposite films containing chitin nanoparticles (N-chitin) with concentrations of 0, 3, 5 and 10% were prepared and their physical, thermal and anti-microbial properties were investigated. Scanning electron microscopy (SEM) micrographs showed that N-chitin size distribution was around 60-70nm which dispersed appropriately at low concentration in gelatin matrix. The results showed that incorporation of N-chitin significantly influenced apparent color and transparency of the gelatin films. The reduced water vapor permeability (WVP) and solubility and higher surface hydrophobicity of the nanocomposite films were obtained by enhancing N-chitin concentration in film formulation. The use of N-chitin up to 5% concentration in the gelatin based nanocomposite film led to improved mechanical properties. Also, the results of differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) confirmed improved stability of nanocomposite films against melting and degradation at high temperatures in comparison to neat gelatin film. The well compatibility of chitin nanoparticles with gelatin polymer was concluded from Fourier transform infrared (FTIR) spectra and X-ray diffraction (XRD) plots. Finally, the gelatin based nanocomposite films had anti-fungal properties against Aspergillus niger in the contact surface zone. Increasing the concentration of N-chitin up to 5% enlarged inhibition zone diameter, but the nanocomposite film containing 10% N-chitin showed smaller inhibition zone. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. High power and high energy electrodes using carbon nanotubes

    Science.gov (United States)

    Martini, Fabrizio; Brambilla, Nicolo Michele; Signorelli, Riccardo

    2015-04-07

    An electrode useful in an energy storage system, such as a capacitor, includes an electrode that includes at least one to a plurality of layers of compressed carbon nanotube aggregate. Methods of fabrication are provided. The resulting electrode exhibits superior electrical performance in terms of gravimetric and volumetric power density.

  5. Manufacturing High-Quality Carbon Nanotubes at Lower Cost

    Science.gov (United States)

    Benavides, Jeanette M.; Lidecker, Henning

    2004-01-01

    A modified electric-arc welding process has been developed for manufacturing high-quality batches of carbon nanotubes at relatively low cost. Unlike in some other processes for making carbon nanotubes, metal catalysts are not used and, consequently, it is not necessary to perform extensive cleaning and purification. Also, unlike some other processes, this process is carried out at atmospheric pressure under a hood instead of in a closed, pressurized chamber; as a result, the present process can be implemented more easily. Although the present welding-based process includes an electric arc, it differs from a prior electric-arc nanotube-production process. The welding equipment used in this process includes an AC/DC welding power source with an integral helium-gas delivery system and circulating water for cooling an assembly that holds one of the welding electrodes (in this case, the anode). The cathode is a hollow carbon (optionally, graphite) rod having an outside diameter of 2 in. (approximately equal to 5.1 cm) and an inside diameter of 5/8 in. (approximately equal to 1.6 cm). The cathode is partly immersed in a water bath, such that it protrudes about 2 in. (about 5.1 cm) above the surface of the water. The bottom end of the cathode is held underwater by a clamp, to which is connected the grounding cable of the welding power source. The anode is a carbon rod 1/8 in. (approximately equal to 0.3 cm) in diameter. The assembly that holds the anode includes a thumbknob- driven mechanism for controlling the height of the anode. A small hood is placed over the anode to direct a flow of helium downward from the anode to the cathode during the welding process. A bell-shaped exhaust hood collects the helium and other gases from the process. During the process, as the anode is consumed, the height of the anode is adjusted to maintain an anode-to-cathode gap of 1 mm. The arc-welding process is continued until the upper end of the anode has been lowered to a specified height

  6. Patterned growth of carbon nanotubes obtained by high density plasma chemical vapor deposition

    Science.gov (United States)

    Mousinho, A. P.; Mansano, R. D.

    2015-03-01

    Patterned growth of carbon nanotubes by chemical vapor deposition represents an assembly approach to place and orient nanotubes at a stage as early as when they are synthesized. In this work, the carbon nanotubes were obtained at room temperature by High Density Plasmas Chemical Vapor Deposition (HDPCVD) system. This CVD system uses a new concept of plasma generation, where a planar coil coupled to an RF system for plasma generation was used with an electrostatic shield for plasma densification. In this mode, high density plasmas are obtained. We also report the patterned growth of carbon nanotubes on full 4-in Si wafers, using pure methane plasmas and iron as precursor material (seed). Photolithography processes were used to pattern the regions on the silicon wafers. The carbon nanotubes were characterized by micro-Raman spectroscopy, the spectra showed very single-walled carbon nanotubes axial vibration modes around 1590 cm-1 and radial breathing modes (RBM) around 120-400 cm-1, confirming that high quality of the carbon nanotubes obtained in this work. The carbon nanotubes were analyzed by atomic force microscopy and scanning electron microscopy too. The results showed that is possible obtain high-aligned carbon nanotubes with patterned growth on a silicon wafer with high reproducibility and control.

  7. Carbon nanotube transistor based high-frequency electronics

    Science.gov (United States)

    Schroter, Michael

    At the nanoscale carbon nanotubes (CNTs) have higher carrier mobility and carrier velocity than most incumbent semiconductors. Thus CNT based field-effect transistors (FETs) are being considered as strong candidates for replacing existing MOSFETs in digital applications. In addition, the predicted high intrinsic transit frequency and the more recent finding of ways to achieve highly linear transfer characteristics have inspired investigations on analog high-frequency (HF) applications. High linearity is extremely valuable for an energy efficient usage of the frequency spectrum, particularly in mobile communications. Compared to digital applications, the much more relaxed constraints for CNT placement and lithography combined with already achieved operating frequencies of at least 10 GHz for fabricated devices make an early entry in the low GHz HF market more feasible than in large-scale digital circuits. Such a market entry would be extremely beneficial for funding the development of production CNTFET based process technology. This talk will provide an overview on the present status and feasibility of HF CNTFET technology will be given from an engineering point of view, including device modeling, experimental results, and existing roadblocks. Carbon nanotube transistor based high-frequency electronics.

  8. High speed capacitor-inverter based carbon nanotube full adder.

    Science.gov (United States)

    Navi, K; Rashtian, M; Khatir, A; Keshavarzian, P; Hashemipour, O

    2010-03-18

    Carbon Nanotube filed-effect transistor (CNFET) is one of the promising alternatives to the MOS transistors. The geometry-dependent threshold voltage is one of the CNFET characteristics, which is used in the proposed Full Adder cell. In this paper, we present a high speed Full Adder cell using CNFETs based on majority-not (Minority) function. Presented design uses eight transistors and eight capacitors. Simulation results show significant improvement in terms of delay and power-delay product in comparison to contemporary CNFET Adder Cells. Simulations were carried out using HSPICE based on CNFET model with 0.6 V VDD.

  9. High yield growth of patterned vertically aligned carbon nanotubes using inkjet-printed catalyst.

    Science.gov (United States)

    Beard, James D; Stringer, Jonathan; Ghita, Oana R; Smith, Patrick J

    2013-10-09

    This study reports on the fabrication of vertically aligned carbon nanotubes localized at specific sites on a growth substrate by deposition of a nanoparticle suspension using inkjet printing. Carbon nanotubes were grown with high yield as vertically aligned forests to a length of approximately 400 μm. The use of inkjet printing for catalyst fabrication considerably improves the production rate of vertically aligned patterned nanotube forests compared with conventional patterning techniques, for example, electron beam lithography or photolithography.

  10. Geckolike high shear strength by carbon nanotube fiber adhesives

    Science.gov (United States)

    Maeno, Y.; Nakayama, Y.

    2009-01-01

    Carbon nanotube adhesives can adhere strongly to surfaces as a gecko does. The number of carbon nanotube layers is an important determinant of the contact area for adhesion. Balancing the catalyst ratio and buffer layer used for chemical vapor deposition processing controls the number of carbon nanotube layers and their distribution. The features of carbon nanotubes determine the shear strength of adhesion. Carbon nanotubes with a broad distribution of layers exhibit enhanced shear strength with equivalent adhesive capability to that of a natural Tokay Gecko (Gekko gecko)

  11. Nanoscale Soldering of Positioned Carbon Nanotubes using Highly Conductive Electron Beam Induced Gold Deposition

    DEFF Research Database (Denmark)

    Madsen, Dorte Nørgaard; Mølhave, Kristian; Mateiu, Ramona Valentina

    2003-01-01

    We have developed an in-situ method for controlled positioning of carbon nanotubes followed by highly conductive contacting of the nanotubes, using electron beam assisted deposition of gold. The positioning and soldering process takes place inside an Environmental Scanning Electron Microscope (E...... in a carbon matrix. Nanoscale soldering of multi-walled carbon nanotubes (MWNT) onto microelectrodes was achieved by deposition of a conducting gold line across a contact point between nanotube and electrode. The solderings were found to be mechanically stronger than the carbon nanotubes. We have positioned...... MWNTs to bridge the gap between two electrodes, and formed soldering bonds between the tube and each of the electrodes. All nanotube bridges showed ohmic resistances in the range 10-30 kΩ. We observed no increase in resistance after exposing the MWNT bridge to air for days....

  12. Synthesis of highly ordered TiO2 nanotube in malonic acid solution by anodization.

    Science.gov (United States)

    Ryu, Won Hee; Park, Chan Jin; Kwon, Hyuk Sang

    2008-10-01

    We synthesized TiO2 nanotube array by anodizing in a solution of malonic acid (HOOCCH2COOH) and NH4F, and analyzed the morphology of the nanotube using scanning electron microscopy (SEM). The morphology of TiO2 nanotube was largely affected by anodizing time, anodizing voltage, and malonic acid concentration. With increasing the anodizing voltage from 5 V to 20 V, the diameter of TiO2 nanotube was increased from about 20 nm to 110 nm and its length from about 10 nm to 700 nm. In addition, the length of TiO2 nanotube was increased with increasing anodizing time up to 6 h at 20 V. We obtained the longest and the most highly ordered nanotube structure when anodizing Ti in a solution of 0.5 wt% NH4F and 1 M malonic acid at 20 V for 6 h.

  13. Growth of highly oriented carbon nanotubes by plasma-enhanced hot filament chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Z.P.; Xu, J.W.; Ren, Z.F.; Wang, J.H. [Materials Synthesis Laboratory, Departments of Physics and Chemistry, and Center for Advanced Photonic and Electronic Materials (CAPEM), State University of New York at Buffalo, Buffalo, New York 14260 (United States); Siegal, M.P.; Provencio, P.N. [Sandia National Laboratories, Albuquerque, New Mexico 87185-1421 (United States)

    1998-12-01

    Highly oriented, multiwalled carbon nanotubes were grown on polished polycrystalline and single crystal nickel substrates by plasma enhanced hot filament chemical vapor deposition at temperatures below 666 {degree}C. The carbon nanotubes range from 10 to 500 nm in diameter and 0.1 to 50 {mu}m in length depending on growth conditions. Acetylene is used as the carbon source for the growth of the carbon nanotubes and ammonia is used for dilution gas and catalysis. The plasma intensity, acetylene to ammonia gas ratio, and their flow rates, etc. affect the diameters and uniformity of the carbon nanotubes. {copyright} {ital 1998 American Institute of Physics.}

  14. Aligned Carbon Nanotubes for High-Performance Films and Composites

    Science.gov (United States)

    Zhang, Liwen

    Carbon nanotubes (CNTs) with extraordinary properties and thus many potential applications have been predicted to be the best reinforcements for the next-generation multifunctional composite materials. Difficulties exist in transferring the most use of the unprecedented properties of individual CNTs to macroscopic forms of CNT assemblies. Therefore, this thesis focuses on two main goals: 1) discussing the issues that influence the performance of bulk CNT products, and 2) fabricating high-performance dry CNT films and composite films with an understanding of the fundamental structure-property relationship in these materials. Dry CNT films were fabricated by a winding process using CNT arrays with heights of 230 mum, 300 im and 360 mum. The structures of the as-produced films, as well as their mechanical and electrical properties were examined in order to find out the effects of different CNT lengths. It was found that the shorter CNTs synthesized by shorter time in the CVD furnace exhibited less structural defects and amorphous carbon, resulting in more compact packing and better nanotube alignment when made into dry films, thus, having better mechanical and electrical performance. A novel microcombing approach was developed to mitigate the CNT waviness and alignment in the dry films, and ultrahigh mechanical properties and exceptional electrical performance were obtained. This method utilized a pair of sharp surgical blades with microsized features at the blade edges as micro-combs to, for the first time, disentangle and straighten the wavy CNTs in the dry-drawn CNT sheet at single-layer level. The as-combed CNT sheet exhibited high level of nanotube alignment and straightness, reduced structural defects, and enhanced nanotube packing density. The dry CNT films produced by microcombing had a very high Young's modulus of 172 GPa, excellent tensile strength of 3.2 GPa, and unprecedented electrical conductivity of 1.8x10 5 S/m, which were records for CNT films or

  15. Freestanding bucky paper with high strength from multi-wall carbon nanotubes

    International Nuclear Information System (INIS)

    Li, Zhonglai; Xu, Ju; O'Byrne, Justin P.; Chen, Lan; Wang, Kaixue; Morris, Michael A.; Holmes, Justin D.

    2012-01-01

    Bucky papers have been investigated by some research groups, however, due to different qualities of carbon nanotubes used, various results of strength and electronic properties were reported in the literatures. In this article, the effects of carbon nanotubes synthesized over different catalysts on the qualities of bucky papers were systemically investigated. Multi-wall carbon nanotubes were synthesized over a series of MgO supported catalysts with different weight ratios of Mo and Co. As the ratios of Mo/Co in the catalysts were increased from 0 to 3, the yields of carbon nanotubes were enhanced from 7 wt% to 400 wt%. However, the yield enhancement of carbon nanotubes was achieved at the expense of higher proportion of structural defects within carbon nanotubes, which has been proved by Raman spectroscopy and thermogravimetry analysis. It was demonstrated that the tensile strength of bucky paper composed of numerous MCNTs bundles strongly depends on the structure of carbon nanotubes used. By optimizing reaction conditions, a bucky paper with high strain up to 15.36 MPa and electrical conductivity of 61.17 S cm −1 was obtained by Supercritical Fluid (SCF) drying technique. -- Highlights: ► Multi-wall carbon nanotube bucky paper. ► Structural defects of carbon nanotubes. ► CoMo catalyst. ► Tensile strength of bucky paper.

  16. High dispersity of carbon nanotubes diminishes immunotoxicity in spleen.

    Science.gov (United States)

    Lee, Soyoung; Khang, Dongwoo; Kim, Sang-Hyun

    2015-01-01

    From the various physiochemical material properties, the chemical functionalization order of single-walled carbon nanotubes (swCNTs) has not been considered as a critical factor for modulating immunological responses and toxicological aspects in drug delivery applications. Although most nanomaterials, including carbon nanotubes, are specifically accumulated in spleen, few studies have focused on spleen immunotoxicity. For this reason, this study demonstrated that the dispersity of swCNTs significantly influenced immunotoxicity in vitro and in vivo. For cytotoxicity of swCNTs, MTT assay, reactive oxygen species production, superoxide dismutase activity, cellular uptake, and confocal microscopy were used in macrophages. In the in vivo study, female BALB/c mice were intravenously administered with 1 mg/kg/day of swCNTs for 2 weeks. The body weight, organ weight, hematological change, reverse-transcription polymerase chain reaction, and lymphocyte population were evaluated. Different orders of chemical functionalization of swCNTs controlled immunotoxicity. In short, less-dispersed swCNTs caused cytotoxicity in macrophages and abnormalities in immune organs such as spleen, whereas highly dispersed swCNTs did not result in immunotoxicity. This study clarified that increasing carboxyl groups on swCNTs significantly mitigated immunotoxicity in vitro and in vivo. Our findings clarified the effective immunotoxicological factors of swCNTs by increasing dispersity of swCNTs and provided useful guidelines for the effective use of nanomaterials.

  17. Fabrication of highly conductive carbon nanotube fibers for electrical application

    International Nuclear Information System (INIS)

    Guo, Fengmei; Li, Can; Wei, Jinquan; Xu, Ruiqiao; Zhang, Zelin; Cui, Xian; Wang, Kunlin; Wu, Dehai

    2015-01-01

    Carbon nanotubes (CNTs) have great potential for use as electrical wires because of their outstanding electrical and mechanical properties. Here, we fabricate lightweight CNT fibers with electrical conductivity as high as that of stainless steel from macroscopic CNT films by drawing them through diamond wire-drawing dies. The entangled CNT bundles are straightened by suffering tension, which improves the alignment of the fibers. The loose fibers are squeezed by the diamond wire-drawing dies, which reduces the intertube space and contact resistance. The CNT fibers prepared by drawing have an electrical conductivity as high as 1.6 × 10 6 s m −1 . The fibers are very stable when kept in the air and under cyclic tensile test. A prototype of CNT motor is demonstrated by replacing the copper wires with the CNT fibers. (paper)

  18. High performance transistors via aligned polyfluorene-sorted carbon nanotubes

    Science.gov (United States)

    Brady, Gerald J.; Joo, Yongho; Singha Roy, Susmit; Gopalan, Padma; Arnold, Michael S.

    2014-02-01

    We evaluate the performance of exceptionally electronic-type sorted, semiconducting, aligned single-walled carbon nanotubes (s-SWCNTs) in field effect transistors (FETs). High on-conductance and high on/off conductance modulation are simultaneously achieved at channel lengths which are both shorter and longer than individual s-SWCNTs. The s-SWCNTs are isolated from heterogeneous mixtures using a polyfluorene-derivative as a selective agent and aligned on substrates via dose-controlled, floating evaporative self-assembly at densities of ˜50 s-SWCNTs μm-1. At a channel length of 9 μm the s-SWCNTs percolate to span the FET channel, and the on/off ratio and charge transport mobility are 2.2 × 107 and 46 cm2 V-1 s-1, respectively. At a channel length of 400 nm, a large fraction of the s-SWCNTs directly span the channel, and the on-conductance per width is 61 μS μm-1 and the on/off ratio is 4 × 105. These results are considerably better than previous solution-processed FETs, which have suffered from poor on/off ratio due to spurious metallic nanotubes that bridge the channel. 4071 individual and small bundles of s-SWCNTs are tested in 400 nm channel length FETs, and all show semiconducting behavior, demonstrating the high fidelity of polyfluorenes as selective agents and the promise of assembling s-SWCNTs from solution to create high performance semiconductor electronic devices.

  19. High performance transistors via aligned polyfluorene-sorted carbon nanotubes

    International Nuclear Information System (INIS)

    Brady, Gerald J.; Joo, Yongho; Singha Roy, Susmit; Gopalan, Padma; Arnold, Michael S.

    2014-01-01

    We evaluate the performance of exceptionally electronic-type sorted, semiconducting, aligned single-walled carbon nanotubes (s-SWCNTs) in field effect transistors (FETs). High on-conductance and high on/off conductance modulation are simultaneously achieved at channel lengths which are both shorter and longer than individual s-SWCNTs. The s-SWCNTs are isolated from heterogeneous mixtures using a polyfluorene-derivative as a selective agent and aligned on substrates via dose-controlled, floating evaporative self-assembly at densities of ∼50 s-SWCNTs μm −1 . At a channel length of 9 μm the s-SWCNTs percolate to span the FET channel, and the on/off ratio and charge transport mobility are 2.2 × 10 7 and 46 cm 2  V −1  s −1 , respectively. At a channel length of 400 nm, a large fraction of the s-SWCNTs directly span the channel, and the on-conductance per width is 61 μS μm −1 and the on/off ratio is 4 × 10 5 . These results are considerably better than previous solution-processed FETs, which have suffered from poor on/off ratio due to spurious metallic nanotubes that bridge the channel. 4071 individual and small bundles of s-SWCNTs are tested in 400 nm channel length FETs, and all show semiconducting behavior, demonstrating the high fidelity of polyfluorenes as selective agents and the promise of assembling s-SWCNTs from solution to create high performance semiconductor electronic devices

  20. High performance transistors via aligned polyfluorene-sorted carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Brady, Gerald J.; Joo, Yongho; Singha Roy, Susmit; Gopalan, Padma; Arnold, Michael S., E-mail: msarnold@wisc.edu [Department of Materials Science and Engineering, University of Wisconsin-Madison, 1509 University Avenue, Madison, Wisconsin 53706 (United States)

    2014-02-24

    We evaluate the performance of exceptionally electronic-type sorted, semiconducting, aligned single-walled carbon nanotubes (s-SWCNTs) in field effect transistors (FETs). High on-conductance and high on/off conductance modulation are simultaneously achieved at channel lengths which are both shorter and longer than individual s-SWCNTs. The s-SWCNTs are isolated from heterogeneous mixtures using a polyfluorene-derivative as a selective agent and aligned on substrates via dose-controlled, floating evaporative self-assembly at densities of ∼50 s-SWCNTs μm{sup −1}. At a channel length of 9 μm the s-SWCNTs percolate to span the FET channel, and the on/off ratio and charge transport mobility are 2.2 × 10{sup 7} and 46 cm{sup 2} V{sup −1} s{sup −1}, respectively. At a channel length of 400 nm, a large fraction of the s-SWCNTs directly span the channel, and the on-conductance per width is 61 μS μm{sup −1} and the on/off ratio is 4 × 10{sup 5}. These results are considerably better than previous solution-processed FETs, which have suffered from poor on/off ratio due to spurious metallic nanotubes that bridge the channel. 4071 individual and small bundles of s-SWCNTs are tested in 400 nm channel length FETs, and all show semiconducting behavior, demonstrating the high fidelity of polyfluorenes as selective agents and the promise of assembling s-SWCNTs from solution to create high performance semiconductor electronic devices.

  1. Well-dispersed cellulose nanocrystals in hydrophobic polymers by in situ polymerization for synthesizing highly reinforced bio-nanocomposites.

    Science.gov (United States)

    Geng, Shiyu; Wei, Jiayuan; Aitomäki, Yvonne; Noël, Maxime; Oksman, Kristiina

    2018-04-20

    In nanocomposites, dispersing hydrophilic nanomaterials in a hydrophobic matrix using simple and environmentally friendly methods remains challenging. Herein, we report a method based on in situ polymerization to synthesize nanocomposites of well-dispersed cellulose nanocrystals (CNCs) and poly(vinyl acetate) (PVAc). We have also shown that by blending this PVAc/CNC nanocomposite with poly(lactic acid) (PLA), a good dispersion of the CNCs can be reached in PLA. The outstanding dispersion of CNCs in both PVAc and PLA/PVAc matrices was shown by different microscopy techniques and was further supported by the mechanical and rheological properties of the composites. The in situ PVAc/CNC nanocomposites exhibit enhanced mechanical properties compared to the materials produced by mechanical mixing, and a theoretical model based on the interphase effect and dispersion that reflects this behavior was developed. Comparison of the rheological and thermal behaviors of the mixed and in situ PVAc/CNC also confirmed the great improvement in the dispersion of nanocellulose in the latter. Furthermore, a synergistic effect was observed with only 0.1 wt% CNCs when the in situ PVAc/CNC was blended with PLA, as demonstrated by significant increases in elastic modulus, yield strength, elongation to break and glass transition temperature compared to the PLA/PVAc only material.

  2. High frequency conductivity of hot electrons in carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Amekpewu, M., E-mail: mamek219@gmail.com [Department of Applied Physics, University for Development Studies, Navrongo (Ghana); Mensah, S.Y. [Department of Physics, College of Agriculture and Natural Sciences, U.C.C. (Ghana); Musah, R. [Department of Applied Physics, University for Development Studies, Navrongo (Ghana); Mensah, N.G. [Department of Mathematics, College of Agriculture and Natural Sciences, U.C.C. (Ghana); Abukari, S.S.; Dompreh, K.A. [Department of Physics, College of Agriculture and Natural Sciences, U.C.C. (Ghana)

    2016-05-01

    High frequency conductivity of hot electrons in undoped single walled achiral Carbon Nanotubes (CNTs) under the influence of ac–dc driven fields was considered. We investigated semi-classically Boltzmann's transport equation with and without the presence of the hot electrons’ source by deriving the current densities in CNTs. Plots of the normalized current density versus frequency of ac-field revealed an increase in both the minimum and maximum peaks of normalized current density at lower frequencies as a result of a strong injection of hot electrons. The applied ac-field plays a twofold role of suppressing the space-charge instability in CNTs and simultaneously pumping an energy for lower frequency generation and amplification of THz radiations. These have enormous promising applications in very different areas of science and technology.

  3. High electron thermal conductivity of chiral carbon nanotubes

    International Nuclear Information System (INIS)

    Mensah, S.Y.; Allotey, F.K.A.; Nkrumah, George; Mensah, N.G.

    2003-11-01

    Solving the Boltzmann kinetic equation with energy dispersion relation obtained in the tight binding approximation, the carrier thermal conductivity κ e of a chiral carbon nanotube (CCNT) was determined. The dependence of κ e on temperature T, chiral geometric angle φ h and overlap integrals Δ z and Δ s were obtained. The results were numerically analysed. Unusually high values of κ e were observed suggesting that ne is nontrivial in the calculation of the thermal conductivity κ of CCNT. More interestingly we noted also that at 104 K and for Δ z and Δ s values of 0.020 eV and 0.0150 eV respectively the κ e value is about 41000 W/mK as reported for a 99.9% pure 12 C crystal. We predict that the electron thermal conductivity of CCNT should exceed 200,000 W/mK at ∼ 80 K. (author)

  4. High aspect ratio piezoelectric strontium-bismuth-tantalate nanotubes

    International Nuclear Information System (INIS)

    Morrison, Finlay D; Ramsay, Laura; Scott, James F

    2003-01-01

    We report the deposition and characterization of transparent ferroelectric/piezoelectric nanotubes of wall thickness about 40 nm, tube diameters ranging from a few hundred nanometres to 4 μm, and length about 100 μm. Comparison with other nanotubes is made and applications in dynamic random access memory trenching and ink-jet printers are discussed. (letter to the editor)

  5. High-performance radio frequency transistors based on diameter-separated semiconducting carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Yu; Che, Yuchi; Zhou, Chongwu, E-mail: chongwuz@usc.edu [Department of Electrical Engineering, University of Southern California, Los Angeles, California 90089 (United States); Seo, Jung-Woo T.; Hersam, Mark C. [Department of Materials Science and Engineering and Department of Chemistry, Northwestern University, Evanston, Illinois 60208 (United States); Gui, Hui [Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089 (United States)

    2016-06-06

    In this paper, we report the high-performance radio-frequency transistors based on the single-walled semiconducting carbon nanotubes with a refined average diameter of ∼1.6 nm. These diameter-separated carbon nanotube transistors show excellent transconductance of 55 μS/μm and desirable drain current saturation with an output resistance of ∼100 KΩ μm. An exceptional radio-frequency performance is also achieved with current gain and power gain cut-off frequencies of 23 GHz and 20 GHz (extrinsic) and 65 GHz and 35 GHz (intrinsic), respectively. These radio-frequency metrics are among the highest reported for the carbon nanotube thin-film transistors. This study provides demonstration of radio frequency transistors based on carbon nanotubes with tailored diameter distributions, which will guide the future application of carbon nanotubes in radio-frequency electronics.

  6. An innovative approach to synthesize highly-ordered TiO2 nanotubes.

    Science.gov (United States)

    Isimjan, Tayirjan T; Yang, D Q; Rohani, Sohrab; Ray, Ajay K

    2011-02-01

    An innovative route to prepare highly-ordered and dimensionally controlled TiO2 nanotubes has been proposed using a mild sonication method. The nanotube arrays were prepared by the anodization of titanium in an electrolyte containing 3% NH4F and 5% H2O in glycerol. It is demonstrated that the TiO2 nanostructures has two layers: the top layer is TiO2 nanowire and underneath is well-ordered TiO2 nanotubes. The top layer can easily fall off and form nanowires bundles by implementing a mild sonication after a short annealing time. We found that the dimensions of the TiO2 nanotubes were only dependent on the anodizing condition. The proposed technique may be extended to fabricate reproducible well-ordered TiO2 nanotubes with large area on other metals.

  7. Facile synthesis of polyaniline nanotubes using reactive oxide templates for high energy density pseudocapacitors

    KAUST Repository

    Chen, Wei

    2013-01-01

    A remarkable energy density of 84 W h kg(cell) -1 and a power density of 182 kW kg(cell) -1 have been achieved for full-cell pseudocapacitors using conducting polymer nanotubes (polyaniline) as electrode materials and ionic liquid as electrolytes. The polyaniline nanotubes were synthesized by a one-step in situ chemical polymerization process utilizing MnO2 nanotubes as sacrificial templates. The polyaniline-nanotube pseudocapacitors exhibit much better electrochemical performance than the polyaniline-nanofiber pseudocapacitors in both acidic aqueous and ionic liquid electrolytes. Importantly, the incorporation of ionic liquid with polyaniline-nanotubes has drastically improved the energy storage capacity of the PAni-nanotube pseudocapacitors by a factor of ∼5 times compared to that of the PAni-nanotube pseudocapacitors in the acidic aqueous electrolyte. Furthermore, even after 10000 cycles, the PAni-nanotube pseudocapacitors in the ionic liquid electrolyte maintain sufficient high energy density and can light LEDs for several minutes, with only 30 s quick charge. © 2013 The Royal Society of Chemistry.

  8. Poly(3,4-ethylenedioxythiophene) nanotubes as electrode materials for a high-powered supercapacitor

    International Nuclear Information System (INIS)

    Liu Ran; Cho, Seung Il; Lee, Sang Bok

    2008-01-01

    We report the fast charging/discharging capability of poly(3,4-ethylenedioxythiophene) (PEDOT) nanotubes during the redox process and their potential application to a high-powered supercapacitor. PEDOT nanotubes were electrochemically synthesized in a porous alumina membrane, and their structures were characterized using electron microscopes. Cyclic voltammetry was used to characterize the specific capacitance of the PEDOT nanotubes at various scan rates. A type I supercapacitor (two symmetric electrodes) based on PEDOT nanotube electrodes was fabricated, and its energy density and power density were evaluated by galvanostatic charge/discharge cycles at various current densities. We show that the PEDOT-nanotube-based supercapacitor can achieve a high power density of 25 kW kg -1 while maintaining 80% energy density (5.6 W h kg -1 ). This high power capability is attributed to the fast charge/discharge of nanotubular structures: hollow nanotubes allow counter-ions to readily penetrate into the polymer and access their internal surfaces, while the thin wall provides a short diffusion distance to facilitate the ion transport. Impedance spectroscopy shows that nanotubes have much lower diffusional resistance to charging ions than solid nanowires shielded by an alumina template, providing supporting information for the high charging/discharging efficiency of nanotubular structures

  9. High performance bulk metallic glass/carbon nanotube composite cathodes for electron field emission

    International Nuclear Information System (INIS)

    Hojati-Talemi, Pejman; Gibson, Mark A.; East, Daniel; Simon, George P.

    2011-01-01

    We report the preparation of new nanocomposites based on a combination of bulk metallic glass and carbon nanotubes for electron field emission applications. The use of bulk metallic glass as the matrix ensures high electrical and thermal conductivity, high thermal stability, and ease of processing, whilst the well dispersed carbon nanotubes act as highly efficient electron emitters. These advantages, alongside excellent electron emission properties, make these composites one of the best reported options for electron emission applications to date.

  10. High performance bulk metallic glass/carbon nanotube composite cathodes for electron field emission

    Energy Technology Data Exchange (ETDEWEB)

    Hojati-Talemi, Pejman [Department of Materials Engineering, Monash University, Clayton, Vic 3800 (Australia); Mawson Institute, University of South Australia, Mawson Lakes, SA 5095 (Australia); Gibson, Mark A. [Process Science and Engineering, Commonwealth Scientific and Industrial Research Organisation, Clayton, Vic 3168 (Australia); East, Daniel; Simon, George P. [Department of Materials Engineering, Monash University, Clayton, Vic 3800 (Australia)

    2011-11-07

    We report the preparation of new nanocomposites based on a combination of bulk metallic glass and carbon nanotubes for electron field emission applications. The use of bulk metallic glass as the matrix ensures high electrical and thermal conductivity, high thermal stability, and ease of processing, whilst the well dispersed carbon nanotubes act as highly efficient electron emitters. These advantages, alongside excellent electron emission properties, make these composites one of the best reported options for electron emission applications to date.

  11. Nanotube phonon waveguide

    Science.gov (United States)

    Chang, Chih-Wei; Zettl, Alexander K.

    2013-10-29

    Disclosed are methods and devices in which certain types of nanotubes (e.g., carbon nanotubes and boron nitride nanotubes conduct heat with high efficiency and are therefore useful in electronic-type devices.

  12. High-performance supercapacitors based on vertically aligned carbon nanotubes and nonaqueous electrolytes

    Science.gov (United States)

    Kim, Byungwoo; Chung, Haegeun; Kim, Woong

    2012-04-01

    We demonstrate the high performance of supercapacitors fabricated with vertically aligned carbon nanotubes and nonaqueous electrolytes such as ionic liquids and conventional organic electrolytes. Specific capacitance, maximum power and energy density of the supercapacitor measured in ionic liquid were ˜75 F g-1, ˜987 kW kg-1 and ˜27 W h kg-1, respectively. The high power performance was consistently indicated by a fast relaxation time constant of 0.2 s. In addition, electrochemical oxidation of the carbon nanotubes improved the specific capacitance (˜158 F g-1) and energy density (˜53 W h kg-1). Both high power and energy density could be attributed to the fast ion transport realized by the alignment of carbon nanotubes and the wide operational voltage defined by the ionic liquid. The demonstrated carbon-nanotube- and nonaqueous-electrolyte-based supercapacitors show great potential for the development of high-performance energy storage devices.

  13. High-performance supercapacitors based on vertically aligned carbon nanotubes and nonaqueous electrolytes.

    Science.gov (United States)

    Kim, Byungwoo; Chung, Haegeun; Kim, Woong

    2012-04-20

    We demonstrate the high performance of supercapacitors fabricated with vertically aligned carbon nanotubes and nonaqueous electrolytes such as ionic liquids and conventional organic electrolytes. Specific capacitance, maximum power and energy density of the supercapacitor measured in ionic liquid were ~75 F g(-1), ~987 kW kg(-1) and ~27 W h kg(-1), respectively. The high power performance was consistently indicated by a fast relaxation time constant of 0.2 s. In addition, electrochemical oxidation of the carbon nanotubes improved the specific capacitance (~158 F g(-1)) and energy density (~53 W h kg(-1)). Both high power and energy density could be attributed to the fast ion transport realized by the alignment of carbon nanotubes and the wide operational voltage defined by the ionic liquid. The demonstrated carbon-nanotube- and nonaqueous-electrolyte-based supercapacitors show great potential for the development of high-performance energy storage devices. © 2012 IOP Publishing Ltd

  14. Hydrotalcites: a highly efficient ecomaterial for effluent treatment originated from carbon nanotubes chemical processing

    Energy Technology Data Exchange (ETDEWEB)

    Alves, O L; Stefani, D; Parizotto, N V; Filho, A G Souza, E-mail: oalves@iqm.unicamp.br [Solid State Chemistry Laboratory, Institute of Chemistry, University of Campinas - UNICAMP, P. O. Box 6154, 13083-970, Campinas-SP (Brazil)

    2011-07-06

    It has been reported that a mixture of carboxylated carbonaceous fragments (CCFs), so called oxidation debris, are generated during carbon nanotubes chemical processing using oxidant agents such as HNO{sub 3}. The elimination of these fragments from carbon nanotubes surface has been point out to be a crucial step for an effective functionalization of the nanotubes as well as for improving the material. However, this process can introduce a potential environmental problem related water contamination because these CCFs can be viewed as a mixture of carbonaceous polyaromatic systems similar to humic substances and dissolved organic matter (DOM). The negative aspects of humic substances and DOM to water quality and wastewater treatment are well known. Since carbon nanotubes industry expands at high rates it is expected that effluent containing oxidation debris will increase since HNO{sub 3} chemical processing is the most applied method for purification and functionalization of carbon nanotubes. In this work, we have demonstrated that Hydrotalcites (HT) are highly efficient to remove oxidation debris from effluent solution originated from HNO{sub 3}-treated multiwalled carbon nanotubes. The strategy presented here is a contribution towards green chemistry practices and life cycle studies in carbon nanotubes field.

  15. High frequency electromechanical memory cells based on telescoping carbon nanotubes.

    Science.gov (United States)

    Popov, A M; Lozovik, Y E; Kulish, A S; Bichoutskaia, E

    2010-07-01

    A new method to increase the operational frequency of electromechanical memory cells based on the telescoping motion of multi-walled carbon nanotubes through the selection of the form of the switching voltage pulse is proposed. The relative motion of the walls of carbon nanotubes can be controlled through the shape of the interwall interaction energy surface. This allows the use of the memory cells in nonvolatile or volatile regime, depending on the structure of carbon nanotube. Simulations based on ab initio and semi-empirical calculations of the interwall interaction energies are used to estimate the switching voltage and the operational frequency of volatile cells with the electrodes made of carbon nanotubes. The lifetime of nonvolatile memory cells is also predicted.

  16. A Highly Viscous Imidazolium Ionic Liquid inside Carbon Nanotubes

    DEFF Research Database (Denmark)

    Ohba, T.; Chaban, Vitaly V.

    2014-01-01

    We report a combined experimental (X-ray diffraction) and theoretical (molecular dynamics, hybrid density functional theory) study of 1-ethyl-3-methylimidazolium chloride, [C2C1MIM][Cl], inside carbon nanotubes (CNTs). We show that despite its huge viscosity [C2C1MIM][Cl] readily penetrates into 1...... adsorption of [C2C1MIM][Cl] on the inner sidewalls of 1-3 nm carbon nanotubes....

  17. High pressure synthesis of amorphous TiO{sub 2} nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Li, Quanjun; Liu, Ran; Wang, Tianyi; Xu, Ke; Dong, Qing; Liu, Bo; Liu, Bingbing, E-mail: liubb@jlu.edu.cn [State Key Laboratory of Superhard Materials, Jilin University, Changchun 130012 (China); Liu, Jing [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China)

    2015-09-15

    Amorphous TiO{sub 2} nanotubes with diameters of 8-10 nm and length of several nanometers were synthesized by high pressure treatment of anatase TiO{sub 2} nanotubes. The structural phase transitions of anatase TiO{sub 2} nanotubes were investigated by using in-situ high-pressure synchrotron X-ray diffraction (XRD) method. The starting anatase structure is stable up to ∼20GPa, and transforms into a high-density amorphous (HDA) form at higher pressure. Pressure-modified high- to low-density transition was observed in the amorphous form upon decompression. The pressure-induced amorphization and polyamorphism are in good agreement with the previous results in ultrafine TiO{sub 2} nanoparticles and nanoribbons. The relationship between the LDA form and α-PbO{sub 2} phase was revealed by high-resolution transmission electron microscopy (HRTEM) study. In addition, the bulk modulus (B{sub 0} = 158 GPa) of the anatase TiO{sub 2} nanotubes is smaller than those of the corresponding bulks and nanoparticles (180-240 GPa). We suggest that the unique open-ended nanotube morphology and nanosize play important roles in the high pressure phase transition of TiO{sub 2} nanotubes.

  18. High Temperature Resin/Carbon Nanotube Composite Fabrication

    Science.gov (United States)

    Ghose, Sayata; Watson, Kent A.; Sun, Keun J.; Criss, Jim M.; Siochi, Emilie J.; Connell, John W.

    2006-01-01

    For the purpose of incorporating multifunctionality into advanced composites, blends of phenylethynyl terminated imides-330 (PETI-330) and multi-walled carbon nanotubes (MWCNTs) were prepared, characterized and fabricated into moldings. PETI-330/MWCNT mixtures were prepared at concentrations ranging from 3 to 25 weight percent by dry mixing the components in a ball mill. The resulting powders were characterized for degree of mixing, thermal and rheological properties. Based on the characterization results, PETI-330/MWCNT samples were scaled up to approximately 300 g and used to fabricate moldings by injecting the mixtures at 260-280 deg C into a stainless steel tool followed by curing for 1 h at 371 deg C. The tool was designed to impart a degree of shear during the injection process in an attempt to achieve some alignment of the MWCNTs in the flow direction. Obtained moldings were subsequently characterized for thermal, mechanical, and electrical properties. The degree of dispersion and alignment of MWCNTs were investigated using high-resolution scanning electron microscopy. The preparation and preliminary characterization of PETI-330/MWCNT composites will be discussed.

  19. Fabrication and structural characterization of highly ordered titania nanotube arrays

    Science.gov (United States)

    Shi, Hongtao; Ordonez, Rosita

    Titanium (Ti) dioxide nanotubes have drawn much attention in the past decade due to the fact that titania is an extremely versatile material with a variety of technological applications. Anodizing Ti in different electrolytes has proved to be quite successful so far in creating the nanotubes, however, their degree of order is still not nearly as good as nanoporous anodic alumina. In this work, we first deposit a thin layer of aluminum (Al) onto electropolished Ti substrates, using thermal evaporation. Such an Al layer is then anodized in 0.3 M oxalic acid, forming an ordered nanoporous alumina mask on top of Ti. Afterwards, the anodization of Ti is accomplished at 20 V in solutions containing 1 M NaH2PO4 and 0.5% HF or H2SO4, which results in the creation of ordered titania nanotube arrays. The inner pore diameter of the nanotubes can be tuned from ~50 nm to ~75 nm, depending on the anodization voltage applied to Al or Ti. X-ray diffractometry shows the as-grown titania nanotubes are amorphous. Samples annealed at different temperatures in ambient atmosphere will be also reported.

  20. Self-Assembled Cu-Sn-S Nanotubes with High (De)Lithiation Performance.

    Science.gov (United States)

    Lin, Jie; Lim, Jin-Myoung; Youn, Duck Hyun; Kawashima, Kenta; Kim, Jun-Hyuk; Liu, Yang; Guo, Hang; Henkelman, Graeme; Heller, Adam; Mullins, Charles Buddie

    2017-10-24

    Through a gelation-solvothermal method without heteroadditives, Cu-Sn-S composites self-assemble to form nanotubes, sub-nanotubes, and nanoparticles. The nanotubes with a Cu 3-4 SnS 4 core and Cu 2 SnS 3 shell can tolerate long cycles of expansion/contraction upon lithiation/delithiation, retaining a charge capacity of 774 mAh g -1 after 200 cycles with a high initial Coulombic efficiency of 82.5%. The importance of the Cu component for mitigation of the volume expansion and structural evolution upon lithiation is informed by density functional theory calculations. The self-generated template and calculated results can inspire the design of analogous Cu-M-S (M = metal) nanotubes for lithium batteries or other energy storage systems.

  1. High activity of novel Pd/TiO2 nanotube catalysts for methanol electro-oxidation

    International Nuclear Information System (INIS)

    Wang Mei; Guo Daojun; Li Hulin

    2005-01-01

    Electro-oxidation of methanol in sulfuric acid solution was studied using palladium well-dispersed on titanium nanotubes, in relation to methanol oxidation processes in the direct oxidation methanol fuel cell. Pd dispersed on titania nanotubes, which leads to high surface area substrates, showed excellent catalytic activities compared to those of pure Pd and Pd-TiO 2 nanoparticles. TEM results show a narrow distribution of TiO 2 nanoparticles whose particle size is about 10nm, and uniform nano-sized TiO 2 nanotubes with 10nm in diameters are seen from HRTEM . A homogeneous structure in the composite nanomaterials is indicated by XRD analysis. The composite electrode activities were measured by cyclic voltammetry (CV) and at 25 deg. C it was found that 3wt% Pd in titania nanotubes had the best activity for methanol oxidation

  2. High-speed logic integrated circuits with solution-processed self-assembled carbon nanotubes.

    Science.gov (United States)

    Han, Shu-Jen; Tang, Jianshi; Kumar, Bharat; Falk, Abram; Farmer, Damon; Tulevski, George; Jenkins, Keith; Afzali, Ali; Oida, Satoshi; Ott, John; Hannon, James; Haensch, Wilfried

    2017-09-01

    As conventional monolithic silicon technology struggles to meet the requirements for the 7-nm technology node, there has been tremendous progress in demonstrating the scalability of carbon nanotube field-effect transistors down to the size that satisfies the 3-nm node and beyond. However, to date, circuits built with carbon nanotubes have overlooked key aspects of a practical logic technology and have stalled at simple functionality demonstrations. Here, we report high-performance complementary carbon nanotube ring oscillators using fully manufacturable processes, with a stage switching frequency of 2.82 GHz. The circuit was built on solution-processed, self-assembled carbon nanotube arrays with over 99.9% semiconducting purity, and the complementary feature was achieved by employing two different work function electrodes.

  3. High-speed logic integrated circuits with solution-processed self-assembled carbon nanotubes

    Science.gov (United States)

    Han, Shu-Jen; Tang, Jianshi; Kumar, Bharat; Falk, Abram; Farmer, Damon; Tulevski, George; Jenkins, Keith; Afzali, Ali; Oida, Satoshi; Ott, John; Hannon, James; Haensch, Wilfried

    2017-09-01

    As conventional monolithic silicon technology struggles to meet the requirements for the 7-nm technology node, there has been tremendous progress in demonstrating the scalability of carbon nanotube field-effect transistors down to the size that satisfies the 3-nm node and beyond. However, to date, circuits built with carbon nanotubes have overlooked key aspects of a practical logic technology and have stalled at simple functionality demonstrations. Here, we report high-performance complementary carbon nanotube ring oscillators using fully manufacturable processes, with a stage switching frequency of 2.82 GHz. The circuit was built on solution-processed, self-assembled carbon nanotube arrays with over 99.9% semiconducting purity, and the complementary feature was achieved by employing two different work function electrodes.

  4. A 66 fs highly stable single wall carbon nanotube mode locked fiber laser

    International Nuclear Information System (INIS)

    Yu, Zhenhua; Zhang, Xiao; Dong, Xinzheng; Tian, Jinrong; Song, Yanrong; Wang, Yonggang

    2014-01-01

    We demonstrate a highly stable mode locked fiber laser based on single wall carbon nanotubes. The mode locking is achieved by the evanescent field interaction of the propagating light with a single wall carbon nanotube saturable absorber in a microfiber. The pulse width is 66 fs, which, to the best of our knowledge, is the shortest pulse achieved in a carbon nanotube mode locked fiber laser. The maximum average output power is 26 mW, which is about 20 times larger than that of a typical carbon nanotube mode locked fiber laser. The center of the wavelength is 1555 nm, with 54 nm spectral width. The repetition rate is 146 MHz. To investigate the laser’s stability, the output pulses are monitored for 120 h and there is no significant degradation of the laser spectral width or shape. (paper)

  5. Mass production of multi-wall carbon nanotubes by metal dusting process with high yield

    Energy Technology Data Exchange (ETDEWEB)

    Ghorbani, H. [School of Metallurgy and Materials Engineering, Iran University of Science and Technology, Narmak, Tehran (Iran, Islamic Republic of); Rashidi, A.M., E-mail: Rashidiam@ripi.ir [Nanotechnology Research Center, Research Institute of Petroleum Industry (RIPI), West Blvd. Azadi Sport Complex, P.O. Box 14665-1998, Tehran (Iran, Islamic Republic of); Rastegari, S.; Mirdamadi, S. [School of Metallurgy and Materials Engineering, Iran University of Science and Technology, Narmak, Tehran (Iran, Islamic Republic of); Alaei, M. [Nanotechnology Research Center, Research Institute of Petroleum Industry (RIPI), West Blvd. Azadi Sport Complex, P.O. Box 14665-1998, Tehran (Iran, Islamic Republic of)

    2011-05-15

    Research highlights: {yields} Synthesis of carbon nanotubes over Fe-Ni nanoparticles supported alloy 304L. {yields} Production of carbon nanotubes with high yield (700-1000%) and low cost catalyst. {yields} Optimum growth condition is CO/H{sub 2} = 1/1, 100 cm{sup 3}/min, at 620 {sup o}C under long term repetitive thermal cycling. {yields} Possibility of the mass production by metal dusting process with low cost. -- Abstract: Carbon nanotube materials were synthesized over Fe-Ni nanoparticles generated during disintegration of the surface of alloy 304L under metal dusting environment. The metal dusting condition was simulated and optimized through exposing stainless steel samples during long term repetitive thermal cycling in CO/H{sub 2} = 1/1, total gas flow rate 100 cm{sup 3}/min, at 620 {sup o}C for 300 h. After reaction, surface morphology of the samples and also carbonaceous deposition which had grown on sample surfaces were examined by stereoscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Results revealed that multi-wall carbon nanotubes could be formed over nanocatalyst generated on the alloy surface by exploiting metal dusting process. By optimization of reaction parameters the yields of carbon nanotube materials obtained were 700-1000%. Also it has been shown herein that the amount of carbon nanotube materials remarkably increases when the reaction time is extended up to 300 h, indicating a possibility of the mass production by this easy method.

  6. Mass production of multi-wall carbon nanotubes by metal dusting process with high yield

    International Nuclear Information System (INIS)

    Ghorbani, H.; Rashidi, A.M.; Rastegari, S.; Mirdamadi, S.; Alaei, M.

    2011-01-01

    Research highlights: → Synthesis of carbon nanotubes over Fe-Ni nanoparticles supported alloy 304L. → Production of carbon nanotubes with high yield (700-1000%) and low cost catalyst. → Optimum growth condition is CO/H 2 = 1/1, 100 cm 3 /min, at 620 o C under long term repetitive thermal cycling. → Possibility of the mass production by metal dusting process with low cost. -- Abstract: Carbon nanotube materials were synthesized over Fe-Ni nanoparticles generated during disintegration of the surface of alloy 304L under metal dusting environment. The metal dusting condition was simulated and optimized through exposing stainless steel samples during long term repetitive thermal cycling in CO/H 2 = 1/1, total gas flow rate 100 cm 3 /min, at 620 o C for 300 h. After reaction, surface morphology of the samples and also carbonaceous deposition which had grown on sample surfaces were examined by stereoscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Results revealed that multi-wall carbon nanotubes could be formed over nanocatalyst generated on the alloy surface by exploiting metal dusting process. By optimization of reaction parameters the yields of carbon nanotube materials obtained were 700-1000%. Also it has been shown herein that the amount of carbon nanotube materials remarkably increases when the reaction time is extended up to 300 h, indicating a possibility of the mass production by this easy method.

  7. Strategies for dispersing carbon nanotubes in highly viscous polymers

    NARCIS (Netherlands)

    Grossiord, N.; Loos, J.; Koning, C.E.

    2005-01-01

    We describe a new technique based on latex technology, which allows the production of conductive composites with potential applications in electronics. These composites consist of exfoliated single-wall nanotubes in a polymer matrix of choice, with very low percolation threshold.

  8. Engineering of High-Toughness Carbon Nanotubes Hierarchically Laminated Composites

    Science.gov (United States)

    2012-01-27

    Bernsmann, F.; Ersen, O.; Voegel, J.-C.; Jan, E.; Kotov, N. A.; Ball, V. Melanin -Containing Films: Growth from Dopamine Solutions versus Layer-by-Layer...Chen, Wei; Doty, Chris; Xu, Chuanlai; Kotov, Nicholas A.. Smart Electronic Yarns and Wearable Fabrics for Human Biomonitoring made by Carbon Nanotube

  9. Guided proliferation and bone-forming functionality on highly ordered large diameter TiO2 nanotube arrays

    International Nuclear Information System (INIS)

    Zhang, Ruopeng; Wu, Hongliu; Ni, Jiahua; Zhao, Changli; Chen, Yifan; Zheng, Chengjunyi; Zhang, Xiaonong

    2015-01-01

    The significantly enhanced osteoblast adhesion, proliferation and alkaline phosphatase (ALP) activity were observed on TiO 2 nanotube surface in recent studies in which the scale of nanotube diameter was restricted under 100 nm. In this paper, a series of highly ordered TiO 2 nanotube arrays with larger diameters ranging from 150 nm to 470 nm were fabricated via high voltage anodization. The behaviors of MC3T3-E1 cells in response to the diameter-controlled TiO 2 nanotubes were investigated. A contrast between the trend of proliferation and the trend of cell elongation was observed. The highest cell elongation (nearly 10:1) and the lowest cell number were observed on the TiO 2 nanotube arrays with 150 nm diameter. While, the lowest cell elongation and highest cell number were achieved on the TiO 2 nanotube arrays with 470 nm diameter. Furthermore, the ALP activity peaked on the 150 nm diameter TiO 2 nanotube arrays and decreased dramatically with the increase of nanotube diameter. Thus a narrow range of diameter (100–200 nm) that could induce the greatest bone-forming activity is determined. It is expected that more delicate design of orthopedic implant with regional abduction of cell proliferation or bone forming could be achieved by controlling the diameter of TiO 2 nanotubes. - Highlights: • Improved anodization methods leading to more ordered large diameter TiO 2 nanotubes • Significantly enhanced ALP activity was observed on 150 nm diameter TiO 2 nanotubes. • The highest cell density was observed on 470 nm diameter TiO 2 nanotube arrays. • Similar cell response was observed on the amorphous and anatase phased nanotube surface

  10. Radio frequency and linearity performance of transistors using high-purity semiconducting carbon nanotubes.

    Science.gov (United States)

    Wang, Chuan; Badmaev, Alexander; Jooyaie, Alborz; Bao, Mingqiang; Wang, Kang L; Galatsis, Kosmas; Zhou, Chongwu

    2011-05-24

    This paper reports the radio frequency (RF) and linearity performance of transistors using high-purity semiconducting carbon nanotubes. High-density, uniform semiconducting nanotube networks are deposited at wafer scale using our APTES-assisted nanotube deposition technique, and RF transistors with channel lengths down to 500 nm are fabricated. We report on transistors exhibiting a cutoff frequency (f(t)) of 5 GHz and with maximum oscillation frequency (f(max)) of 1.5 GHz. Besides the cutoff frequency, the other important figure of merit for the RF transistors is the device linearity. For the first time, we report carbon nanotube RF transistor linearity metrics up to 1 GHz. Without the use of active probes to provide the high impedance termination, the measurement bandwidth is therefore not limited, and the linearity measurements can be conducted at the frequencies where the transistors are intended to be operating. We conclude that semiconducting nanotube-based transistors are potentially promising building blocks for highly linear RF electronics and circuit applications.

  11. Controlled nanostructure and high loading of single-walled carbon nanotubes reinforced polycarbonate composite

    International Nuclear Information System (INIS)

    Wang Shiren; Liang Zhiyong; Pham, Giang; Park, Young-Bin; Wang, Ben; Zhang, Chuck; Kramer, Leslie; Funchess, Percy

    2007-01-01

    This paper presents an effective technique to fabricate thermoplastic nanocomposites with high loading of well-dispersed single-walled carbon nanotubes (SWNTs). SWNT membranes were made from a multi-step dispersion and filtration method, and then impregnated with polycarbonate solution to make thermoplastic nanocomposites. High loading of nanotubes was achieved by controlling the viscosity of polycarbonate solution. SEM and AFM characterization results revealed the controlled nanostructure in the resultant nanocomposites. Dynamic mechanical property tests indicated that the storage modulus of the resulting nanocomposites at 20 wt% nanotubes loading was improved by a factor of 3.4 compared with neat polycarbonate material. These results suggest the developed approach is an effective way to fabricate thermoplastic nanocomposites with good dispersion and high SWNT loading

  12. A novel method for the fabrication of a high-density carbon nanotube microelectrode array

    Directory of Open Access Journals (Sweden)

    Adam Khalifa

    2015-09-01

    Full Text Available We present a novel method for fabricating a high-density carbon nanotube microelectrode array (MEA chip. Vertically aligned carbon nanotubes (VACNTs were synthesized by microwave plasma-enhanced chemical vapor deposition and thermal chemical vapor deposition. The device was characterized using electrochemical experiments such as cyclic voltammetry, impedance spectroscopy and potential transient measurements. Through-silicon vias (TSVs were fabricated and partially filled with polycrystalline silicon to allow electrical connection from the high-density electrodes to a stimulator microchip. In response to the demand for higher resolution implants, we have developed a unique process to obtain a high-density electrode array by making the microelectrodes smaller in size and designing new ways of routing the electrodes to current sources. Keywords: Microelectrode array, Neural implant, Carbon nanotubes, Through-silicon via interconnects, Microfabrication

  13. Driving High-Performance n- and p-type Organic Transistors with Carbon Nanotube/Conjugated Polymer Composite Electrodes Patterned Directly from Solution

    KAUST Repository

    Hellstrom, Sondra L.; Jin, Run Zhi; Stoltenberg, Randall M.; Bao, Zhenan

    2010-01-01

    We report patterned deposition of carbon nanotube/conjugated polymer composites from solution with high nanotube densities and excellent feature resolution. Such composites are suited for use as electrodes in high-performance transistors

  14. High Volume Fraction Carbon Nanotube Composites for Aerospace Applications

    Science.gov (United States)

    Siochi, E. J.; Kim, J.-W.; Sauti, G.; Cano, R. J.; Wincheski, R. A.; Ratcliffe, J. G.; Czabaj, M.

    2016-01-01

    Reported mechanical properties of carbon nanotubes (CNTs) at the nanoscale suggest their potential to enable significantly lighter structures of interest for space applications. However, their utility depends on the retention of these properties in bulk material formats that permit practical fabrication of large structures. This presentation summarizes recent progress made to produce carbon nanotube composites with specific tensile properties that begin to rival those of carbon fiber reinforced polymer composites. CNT content in these nanocomposites was greater than 70% by weight. Tested nanocomposite specimens were fabricated from kilometers or tens of square meters of CNT, depending on the starting material format. Processing methods to yield these results, and characterization and testing to evaluate the performance of these composites will be discussed. The final objective is the demonstration of a CNT composite overwrapped pressure vessel to be flight tested in the Fall of 2016.

  15. Ultra High Energy Density Cathodes with Carbon Nanotubes

    Science.gov (United States)

    2013-12-10

    a) Carbon nanotube paper coated with NCA cathode composite for testing as positive electrode in Li-ion battery (b) Comparison of NCA specific...received and purified CNT electrodes coated with NCA cathode composite. (b) Discharge capacities as a function of rate and cycle for NCA on Al and...thickness increases. The first approach was to cast SOA NCA cathode composites onto CNT current collectors using an adjustable blade coater. The

  16. Cellular cytotoxic response induced by highly purified multi-wall carbon nanotube in human lung cells.

    Science.gov (United States)

    Tsukahara, Tamotsu; Haniu, Hisao

    2011-06-01

    Carbon nanotubes, a promising nanomaterial with unique characteristics, have applications in a variety of fields. The cytotoxic effects of carbon nanotubes are partially due to the induction of oxidative stress; however, the detailed mechanisms of nanotube cytotoxicity and their interaction with cells remain unclear. In this study, the authors focus on the acute toxicity of vapor-grown carbon fiber, HTT2800, which is one of the most highly purified multi-wall carbon nanotubes (MWCNT) by high-temperature thermal treatment. The authors exposed human bronchial epithelial cells (BEAS-2B) to HTT2800 and measured the cellular uptake, mitochondrial function, cellular LDH release, apoptotic signaling, reactive oxygen species (ROS) generation and pro-inflammatory cytokine release. The HTT2800-exposed cells showed cellular uptake of the carbon nanotube, increased cell death, enhanced DNA damage, and induced cytokine release. However, the exposed cells showed no obvious intracellular ROS generation. These cellular and molecular findings suggest that HTT2800 could cause a potentially adverse inflammatory response in BEAS-2B cells.

  17. A graphene oxide-carbon nanotube grid for high-resolution transmission electron microscopy of nanomaterials

    International Nuclear Information System (INIS)

    Zhang Lina; Zhang Haoxu; Zhou Ruifeng; Chen Zhuo; Li Qunqing; Fan Shoushan; Jiang Kaili; Ge Guanglu; Liu Renxiao

    2011-01-01

    A novel grid for use in transmission electron microscopy is developed. The supporting film of the grid is composed of thin graphene oxide films overlying a super-aligned carbon nanotube network. The composite film combines the advantages of graphene oxide and carbon nanotube networks and has the following properties: it is ultra-thin, it has a large flat and smooth effective supporting area with a homogeneous amorphous appearance, high stability, and good conductivity. The graphene oxide-carbon nanotube grid has a distinct advantage when characterizing the fine structure of a mass of nanomaterials over conventional amorphous carbon grids. Clear high-resolution transmission electron microscopy images of various nanomaterials are obtained easily using the new grids.

  18. Revealing properties of single-walled carbon nanotubes under high pressure

    CERN Document Server

    Tang Jie; Sasaki, T; Yudasaka, M; Matsushita, A; Iijima, S

    2002-01-01

    It was found by the x-ray diffraction experiment under hydrostatic pressure that the carbon nanotubes are compressed easily with a high volume compressibility of 0.024 GPa sup - sup 1. The single-walled carbon nanotubes are polygonized when they form bundles of hexagonal close-packed structure and the inter-tubular gap is smaller than the equilibrium spacing of graphite. Under high pressure, further polygonization occurs to accommodate the extra amount of volume reduction. The ratio of the short and the long diagonals in the hexagonalized cross section is found to have changed from 0.991 at zero pressure to 0.982 at 1.5 GPa pressure, when the Bragg reflection from the nanotube lattice diminished. Accompanying polygonization, a discontinuous change in electrical resistivity was observed at 1.5 GPa pressure, suggesting a phase transition had occurred.

  19. Crosslinked Carbon Nanotubes/Polyaniline Composites as a Pseudocapacitive Material with High Cycling Stability

    Directory of Open Access Journals (Sweden)

    Dong Liu

    2015-06-01

    Full Text Available The poor cycling stability of polyaniline (PANI limits its practical application as a pseudocapacitive material due to the volume change during the charge-discharge procedure. Herein, crosslinked carbon nanotubes/polyaniline (C-CNTs/PANI composites had been designed by the in situ chemical oxidative polymerization of aniline in the presence of crosslinked carbon nanotubes (C-CNTs, which were obtained by coupling of the functionalized carbon nanotubes with 1,4-benzoquinone. The composite showed a specific capacitance of 294 F/g at the scan rate of 10 mV/s, and could retain 95% of its initial specific capacitance after 1000 CV cycles. Such high electrochemical cycling stability resulting from the crosslinked skeleton of the C-CNTs makes them potential electrode materials for a supercapacitor.

  20. Effects of highly ordered TiO2 nanotube substrates on the nucleation of Cu electrodeposits.

    Science.gov (United States)

    Ryu, Won Hee; Park, Chan Jin; Kwon, Hyuk Sang

    2010-05-01

    We investigated the effects of TiO2 nanotube substrates on the nucleation density of Cu during electrodeposition in a solution of CuSO4 and H2SO4 at 50 degrees C compared with those of pure Ti and micro-porous TiO2 substrates. During electrodeposition, the density of Cu nuclei on the TiO2 nanotube substrate increased and the average size of Cu nuclei decreased with increasing anodizing voltage and time for the synthesis of the substrate. In addition, the nucleation density of Cu electrodeposits on the highly ordered TiO2 nanotube substrate was much higher than that on pure Ti and micro-porous TiO2 substrates.

  1. High power density supercapacitor electrodes of carbon nanotube films by electrophoretic deposition

    International Nuclear Information System (INIS)

    Du Chunsheng; Pan Ning

    2006-01-01

    Carbon nanotube thin films have been successfully fabricated by the electrophoretic deposition technique. The supercapacitors built from such thin film electrodes have a very small equivalent series resistance, and a high specific power density over 20 kW kg -1 was thus obtained. More importantly, the supercapacitors showed superior frequency response. Our study also demonstrated that these carbon nanotube thin films can serve as coating layers over ordinary current collectors to drastically enhance the electrode performance, indicating a huge potential in supercapacitor and battery manufacturing

  2. Highly aligned carbon nanotube arrays fabricated by bias sputtering

    International Nuclear Information System (INIS)

    Hayashi, Nobuyuki; Honda, Shin-ichi; Tsuji, Keita; Lee, Kuei-Yi; Ikuno, Takashi; Fujimoto, Keiichi; Ohkura, Shigeharu; Katayama, Mitsuhiro; Oura, Kenjiro; Hirao, Takashi

    2003-01-01

    Vertically aligned carbon nanotube (CNT) arrays have been successfully grown on Si substrates by dc bias sputtering. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observations revealed that the resultant arrays consisted of dense CNTs with diameters of 40-60 nm and lengths of 300-400 nm. The CNTs were found to have a bamboo-like structure at the end of which metallic nanoparticle was formed, indicating tip growth mechanism. The energy enhancement of carbon particles is a key factor for synthesis of CNTs using dc bias sputtering system

  3. Hardness of high-pressure high-temperature treated single-walled carbon nanotubes

    International Nuclear Information System (INIS)

    Kawasaki, S.; Nojima, Y.; Yokomae, T.; Okino, F.; Touhara, H.

    2007-01-01

    We have performed high-pressure high-temperature (HPHT) treatments of high quality single-walled carbon nanotubes (SWCNTs) over a wide pressure-temperature range up to 13 GPa-873 K and have investigated the hardness of the HPHT-treated SWCNTs using a nanoindentation technique. It was found that the hardness of the SWCNTs treated at pressures greater than 11 GPa and at temperatures higher than 773 K is about 10 times greater than that of the SWCNTs treated at low temperature. It was also found that the hardness change of the SWCNTs is related to the structural change by the HPHT treatments which was based on synchrotron X-ray diffraction measurements

  4. High pressure Raman spectroscopy of single-walled carbon nanotubes: Effect of chemical environment on individual nanotubes and the nanotube bundle

    Science.gov (United States)

    Proctor, John E.; Halsall, Matthew P.; Ghandour, Ahmad; Dunstan, David J.

    2006-12-01

    The pressure-induced tangential mode Raman peak shifts for single-walled carbon nanotubes (SWNTs) have been studied using a variety of different solvents as hydrostatic pressure-transmitting media. The variation in the nanotube response to hydrostatic pressure with different pressure transmitting media is evidence that the common solvents used are able to penetrate the interstitial spaces in the nanotube bundle. With hexane, we find the surprising result that the individual nanotubes appear unaffected by hydrostatic pressures (i.e. a flat Raman response) up to 0.7 GPa. Qualitatively similar results have been obtained with butanol. Following the approach of Amer et al. [J. Chem. Phys. 121 (2004) 2752], we speculate that this is due to the inability of SWNTs to adsorb some solvents onto their surface at lower pressures. We also find that the role of cohesive energy density in the solvent nanotube interaction is more complex than previously thought.

  5. Fabrication of nickel hydroxide electrodes with open-ended hexagonal nanotube arrays for high capacitance supercapacitors.

    Science.gov (United States)

    Wu, Mao-Sung; Huang, Kuo-Chih

    2011-11-28

    A nickel hydroxide electrode with open-ended hexagonal nanotube arrays, prepared by hydrolysis of nickel chloride in the presence of hexagonal ZnO nanorods, shows a very high capacitance of 1328 F g(-1) at a discharge current density of 1 A g(-1) due to the significantly improved ion transport.

  6. Growth of Carbon Nanotubes on Clay: Unique Nanostructured Filler for High-Performance Polymer Nanocomposites

    NARCIS (Netherlands)

    Zhang, Wei-De; Phang, In Yee; Liu, Tianxi

    2006-01-01

    High-performance composites are produced using nanostructured clay-carbon nanotube (CNT) hybrids as a reinforcing filler. The intercalation of iron particles between the clay platelets serves as the catalyst for the growth of CNTs, while the platelets are exfoliated by the CNTs, forming the unique

  7. Aligned Carbon Nanotubes for Highly Efficient Energy Generation and Storage Devices

    Science.gov (United States)

    2012-01-24

    solution processing methods, including filtration, solution-casting, electrophoretic deposition, and Langmuir - Blodgett deposition. However, most...supercapacitors with environmentally friendly ionic liquid electrolytes. These new nanocomposite electrodes consist of the high-surface-area activated...carbons, carbon nanotubes, and ionic liquids as the integrated constituent components. The resultant composites show significantly improved charge

  8. High-performance supercapacitors based on vertically aligned carbon nanotubes and nonaqueous electrolytes

    International Nuclear Information System (INIS)

    Kim, Byungwoo; Kim, Woong; Chung, Haegeun

    2012-01-01

    We demonstrate the high performance of supercapacitors fabricated with vertically aligned carbon nanotubes and nonaqueous electrolytes such as ionic liquids and conventional organic electrolytes. Specific capacitance, maximum power and energy density of the supercapacitor measured in ionic liquid were ∼75 F g −1 , ∼987 kW kg −1 and ∼27 W h kg −1 , respectively. The high power performance was consistently indicated by a fast relaxation time constant of 0.2 s. In addition, electrochemical oxidation of the carbon nanotubes improved the specific capacitance (∼158 F g −1 ) and energy density (∼53 W h kg −1 ). Both high power and energy density could be attributed to the fast ion transport realized by the alignment of carbon nanotubes and the wide operational voltage defined by the ionic liquid. The demonstrated carbon-nanotube- and nonaqueous-electrolyte-based supercapacitors show great potential for the development of high-performance energy storage devices. (paper)

  9. Creating high yield water soluble luminescent graphene quantum dots via exfoliating and disintegrating carbon nanotubes and graphite flakes.

    Science.gov (United States)

    Lin, Liangxu; Zhang, Shaowei

    2012-10-21

    We have developed an effective method to exfoliate and disintegrate multi-walled carbon nanotubes and graphite flakes. With this technique, high yield production of luminescent graphene quantum dots with high quantum yield and low oxidization can be achieved.

  10. Novel iron oxide nanotube arrays as high-performance anodes for lithium ion batteries

    Science.gov (United States)

    Zhong, Yuan; Fan, Huiqing; Chang, Ling; Shao, Haibo; Wang, Jianming; Zhang, Jianqing; Cao, Chu-nan

    2015-11-01

    Nanostructured iron oxides can be promising anode materials for lithium ion batteries (LIBs). However, improvement on the rate capability and/or electrochemical cycling stability of iron oxide anode materials remains a key challenge because of their poor electrical conductivities and large volume expansion during cycling. Herein, the vertically aligned arrays of one-dimensional (1D) iron oxide nanotubes with 5.8 wt% carbon have been fabricated by a novel surfactant-free self-corrosion process and subsequent thermal treatment. The as-fabricated nanotube array electrode delivers a reversible capacity of 932 mAh g-1 after 50 charge-discharge cycles at a current of 0.6 A g-1. The electrode still shows a reversible capacity of 610 mAh g-1 even at a very high rate (8.0 A g-1), demonstrating its prominent rate capability. Furthermore, the nanotube array electrode also exhibits the excellent electrochemical cycling stability with a reversible capacity of 880 mAh g-1 after 500 cycles at a current of 4 A g-1. The nanotube array electrode with superior lithium storage performance reveals the promising potential as a high-performance anode for LIBs.

  11. Highly conductive interwoven carbon nanotube and silver nanowire transparent electrodes

    Directory of Open Access Journals (Sweden)

    Andrew J Stapleton, Rakesh A Afre, Amanda V Ellis, Joe G Shapter, Gunther G Andersson, Jamie S Quinton and David A Lewis

    2013-01-01

    Full Text Available Electrodes fabricated using commercially available silver nanowires (AgNWs and single walled carbon nanotubes (SWCNTs produced sheet resistances in the range 4–24 Ω squ−1 with specular transparencies up to 82 %. Increasing the aqueous dispersibility of SWCNTs decreased the bundle size present in the film resulting in improved SWCNT surface dispersion in the films without compromising transparency or sheet resistance. In addition to providing conduction pathways between the AgNW network, the SWCNTs also provide structural support, creating stable self-supporting films. Entanglement of the AgNWs and SWCNTs was demonstrated to occur in solution prior to deposition by monitoring the transverse plasmon resonance mode of the AgNWs during processing. The interwoven AgNW/SWCNT structures show potential for use in optoelectronic applications as transparent electrodes and as an ITO replacement.

  12. Well-Shaped Sulfonic Organosilica Nanotubes with High Activity for Hydrolysis of Cellobiose

    Directory of Open Access Journals (Sweden)

    Jing Sun

    2017-04-01

    Full Text Available Sulfonic organosilica nanotubes with different acidity densities could be synthesized through the co-condensation of ethenyl- or phenylene-bridged organosilane and 3-mercaptopropyltrimethoxysilane followed by sulfhydryl (–SH oxidation. Transmission electron microscopy (TEM analysis and nitrogen adsorption-desorption experiment clearly exhibit the hollow nanotube structures with the diameters of about 5 nm. The compositions of the nanotube frameworks are confirmed by solid state 13C nuclear magnetic resonance (NMR while X-ray photoelectron spectroscopy (XPS shows that about 60–80% of SH groups were oxidized to sulfonic acid (SO3H. The acid contents were measured by both elemental analysis (CHNS mode and acid-base titration experiment, which revealed that the acid density was in the range of 0.74 to 4.37 μmol·m−2 on the solid. These nanotube-based acid catalysts exhibited excellent performances in the hydrolysis of cellobiose with the highest conversion of 92% and glucose selectivity of 96%. In addition, the catalysts could maintain high activity (65% conversion with 92% selectivity even after six recycles.

  13. Extremely high thermal conductivity anisotropy of double-walled carbon nanotubes

    Directory of Open Access Journals (Sweden)

    Zhaoji Ma

    2017-06-01

    Full Text Available Based on molecular dynamics simulations, we reveal that double-walled carbon nanotubes can possess an extremely high anisotropy ratio of radial to axial thermal conductivities. The mechanism is basically the same as that for the high thermal conductivity anisotropy of graphene layers - the in-plane strong sp2 bonds lead to a very high intralayer thermal conductivity while the weak van der Waals interactions to a very low interlayer thermal conductivity. However, different from flat graphene layers, the tubular structures of carbon nanotubes result in a diameter dependent thermal conductivity. The smaller the diameter, the larger the axial thermal conductivity but the smaller the radial thermal conductivity. As a result, a DWCNT with a small diameter may have an anisotropy ratio of thermal conductivity significantly higher than that for graphene layers. The extremely high thermal conductivity anisotropy allows DWCNTs to be a promising candidate for thermal management materials.

  14. Platinum decorated carbon nanotubes for highly sensitive amperometric glucose sensing

    International Nuclear Information System (INIS)

    Xie Jining; Wang Shouyan; Aryasomayajula, L; Varadan, V K

    2007-01-01

    Fine platinum nanoparticles (1-5 nm in diameter) were deposited on functionalized multi-walled carbon nanotubes (MWNTs) through a decoration technique. A novel type of enzymatic Pt/MWNTs paste-based mediated glucose sensor was fabricated. Electrochemical measurements revealed a significantly improved sensitivity (around 52.7 μA mM -1 cm -2 ) for glucose sensing without using any picoampere booster or Faraday cage. In addition, the calibration curve exhibited a good linearity in the range of 1-28 mM of glucose concentration. Transmission electron microscopy (TEM) and x-ray photoelectron spectroscopy (XPS) were performed to investigate the nanoscale structure and the chemical bonding information of the Pt/MWNTs paste-based sensing material, respectively. The improved sensitivity of this novel glucose sensor could be ascribed to its higher electroactive surface area, enhanced electron transfer, efficient enzyme immobilization, unique interaction in nanoscale and a synergistic effect on the current signal from possible multi-redox reactions

  15. Laser-engraved carbon nanotube paper for instilling high sensitivity, high stretchability, and high linearity in strain sensors

    KAUST Repository

    Xin, Yangyang

    2017-06-29

    There is an increasing demand for strain sensors with high sensitivity and high stretchability for new applications such as robotics or wearable electronics. However, for the available technologies, the sensitivity of the sensors varies widely. These sensors are also highly nonlinear, making reliable measurement challenging. Here we introduce a new family of sensors composed of a laser-engraved carbon nanotube paper embedded in an elastomer. A roll-to-roll pressing of these sensors activates a pre-defined fragmentation process, which results in a well-controlled, fragmented microstructure. Such sensors are reproducible and durable and can attain ultrahigh sensitivity and high stretchability (with a gauge factor of over 4.2 × 10(4) at 150% strain). Moreover, they can attain high linearity from 0% to 15% and from 22% to 150% strain. They are good candidates for stretchable electronic applications that require high sensitivity and linearity at large strains.

  16. High-performance supercapacitors of Cu-based porous coordination polymer nanowires and the derived porous CuO nanotubes.

    Science.gov (United States)

    Wu, Meng-Ke; Zhou, Jiao-Jiao; Yi, Fei-Yan; Chen, Chen; Li, Yan-Li; Li, Qin; Tao, Kai; Han, Lei

    2017-12-12

    Electrode materials for supercapacitors with one-dimensional porous nanostructures, such as nanowires and nanotubes, are very attractive for high-efficiency storage of electrochemical energy. Herein, ultralong Cu-based porous coordination polymer nanowires (copper-l-aspartic acid) were used as the electrode material for supercapacitors, for the first time. The as-prepared material exhibits a high specific capacitance of 367 F g -1 at 0.6 A g -1 and excellent cycling stability (94% retention over 1000 cycles). Moreover, porous CuO nanotubes were successfully fabricated by the thermal decomposition of this nanowire precursor. The CuO nanotube exhibits good electrochemical performance with high rate capacity (77% retention at 12.5 A g -1 ) and long-term stability (96% retention over 1000 cycles). The strategy developed here for the synthesis of porous nanowires and nanotubes can be extended to the construction of other electrode materials for more efficient energy storage.

  17. Examination of the high-frequency capability of carbon nanotube FETs

    Science.gov (United States)

    Pulfrey, David L.; Chen, Li

    2008-09-01

    New results are added to a recent critique of the high-frequency performance of carbon nanotube field-effect transistors (CNFETs). On the practical side, reduction of the number of metallic tubes in CNFETs fashioned from multiple nanotubes has allowed the measured fT to be increased to 30 GHz. On the theoretical side, the opinion that the band-structure-determined velocity limits the high-frequency performance has been reinforced by corrections to recent simulation results for doped-contact CNFETs, and by the ruling out of the possibility of favourable image-charge effects. Inclusion in the simulations of the features of finite gate-metal thickness and source/drain contact resistance has given an indication of likely practical values for fT. A meaningful comparison between CNFETs with doped-contacts and metallic contacts has been made.

  18. A Microneedle Functionalized with Polyethyleneimine and Nanotubes for Highly Sensitive, Label-Free Quantification of DNA

    OpenAIRE

    Saadat-Moghaddam, Darius; Kim, Jong-Hoon

    2017-01-01

    The accurate measure of DNA concentration is necessary for many DNA-based biological applications. However, the current methods are limited in terms of sensitivity, reproducibility, human error, and contamination. Here, we present a microneedle functionalized with polyethyleneimine (PEI) and single-walled carbon nanotubes (SWCNTs) for the highly sensitive quantification of DNA. The microneedle was fabricated using ultraviolet (UV) lithography and anisotropic etching, and then functionalized w...

  19. A highly durable fuel cell electrocatalyst based on double-polymer-coated carbon nanotubes.

    Science.gov (United States)

    Berber, Mohamed R; Hafez, Inas H; Fujigaya, Tsuyohiko; Nakashima, Naotoshi

    2015-11-23

    Driven by the demand for the commercialization of fuel cell (FC) technology, we describe the design and fabrication of a highly durable FC electrocatalyst based on double-polymer-coated carbon nanotubes for use in polymer electrolyte membrane fuel cells. The fabricated electrocatalyst is composed of Pt-deposited polybenzimidazole-coated carbon nanotubes, which are further coated with Nafion. By using this electrocatalyst, a high FC performance with a power density of 375 mW/cm(2) (at 70 ˚C, 50% relative humidity using air (cathode)/H2(anode)) was obtained, and a remarkable durability of 500,000 accelerated potential cycles was recorded with only a 5% loss of the initial FC potential and 20% loss of the maximum power density, which were far superior properties compared to those of the membrane electrode assembly prepared using carbon black in place of the carbon nanotubes. The present study indicates that the prepared highly durable fuel cell electrocatalyst is a promising material for the next generation of PEMFCs.

  20. In situ electrical probing and bias-mediated manipulation of dielectric nanotubes in a high-resolution transmission electron microscope

    International Nuclear Information System (INIS)

    Golberg, D.; Mitome, M.; Kurashima, K.; Zhi, C.Y.; Tang, C.C.; Bando, Y.; Lourie, O.

    2006-01-01

    Boron nitride nanotubes filled with magnesium oxides [MgO, MgO 2 ] and/or hydroxide [Mg(OH) 2 ] are electrically probed and delicately manipulated inside a 300 kV JEOL-3000F high-resolution transmission analytical electron microscope equipped with a side-entry 'Nanofactory Instruments' piezoholder. At a low bias the nanotubes demonstrate truly insulating behavior. At a high bias of ±30 V they show reversible breakdown current of several dozens of nA. Under 300 kV electron beam irradiation the nanotubes are positively charged that allows us to perform on-demand manipulation with them through tuning of polarity and/or value of a bias voltage on a gold counterelectrode from -140 to +140 V, owing to the prominent electrostatic nanotube-electrode interactions

  1. High quantum yield graphene quantum dots decorated TiO_2 nanotubes for enhancing photocatalytic activity

    International Nuclear Information System (INIS)

    Qu, Ailan; Xie, Haolong; Xu, Xinmei; Zhang, Yangyu; Wen, Shengwu; Cui, Yifan

    2016-01-01

    Highlights: • High concentration yellow GQDs and TiO_2 nanotubes were achieved by a simple and green method. • High quantum yield GQDs enhanced the photodegradation capacity of TiO_2 nanotube. • The catalytic performance of GQDs/TiO_2 depends on the GQDs loading. • The improved photocatalytic activity of GQDs/TiO_2 was attributed to three aspects. - Abstract: Graphene quantum dots (GQDs) with high quantum yield (about 23.6% at an excitation wavelength of 320 nm) and GQDs/TiO_2 nanotubes (GQDs/TiO_2 NTs) composites were achieved by a simple hydrothermal method at low temperature. Photoluminescence characterization showed that the GQDs exhibited the down-conversion PL features at excitation from 300 to 420 nm and up-conversion photoluminescence in the range of 600–800 nm. The photocatalytic activity of prepared GQDs/TiO_2 NTs composites on the degradation of methyl orange (MO) was significantly enhanced compared with that of pure TiO_2 nanotubes (TiO_2 NTs). For the composites coupling with 1.5%, 2.5% and 3.5% GQDs, the degradation of MO after 20 min irradiation under UV–vis light irradiation (λ = 380–780 nm) were 80.52%, 94.64% and 51.91%, respectively, which are much higher than that of pure TiO_2 NTs (35.41%). It was inferred from the results of characterization that the improved photocatalytic activity of the GQDs/TiO_2 NTs composites was attributed to the synergetic effect of up-conversion properties of the GQDs, enhanced visible light absorption and efficient separation of photogenerated electron-holes of the GQDs/TiO_2 composite.

  2. Fast fabrication of long TiO2 nanotube array with high photoelectrochemical property on flexible stainless steel.

    Science.gov (United States)

    Tao, Jie; Wu, Tao; Gao, Peng

    2012-03-01

    Oriented highly ordered long TiO2 nanotube array films with nanopore structure and high photoelectrochemical property were fabricated on flexible stainless steel substrate (50 microm) by anodization treatment of titanium thin films in a short time. The samples were characterized by means of field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD) and photoelectrochemical methods, respectively. The results showed that Ti films deposited at the condition of 0.7 Pa Ar pressure and 96 W sputtering power at room temperature was uniform and dense with good homogeneity and high crystallinity. The voltage and the anodization time both played significant roles in the formation of TiO2 nanopore-nanotube array film. The optimal voltage was 60 V and the anodization time is less than 30 min by anodizing Ti films in ethylene glycerol containing 0.5% (w) NH4F and 3% (w) H2O. The growth rate of TiO2 nanotube array was as high as 340 nm/min. Moreover, the photocurrent-potential curves, photocurrent response curves and electrochemical impedance spectra results indicated that the TiO2 nanotube array film with the nanoporous structure exhibited a better photo-response ability and photoelectrochemical performance than the ordinary TiO2 nanotube array film. The reason is that the nanoporous structure on the surface of the nanotube array can separate the photo electron-hole pairs more efficiently and completely than the tubular structure.

  3. Double-side illuminated titania nanotubes for high volume hydrogen generation by water splitting

    Science.gov (United States)

    Mohapatra, Susanta K.; Mahajan, Vishal K.; Misra, Mano

    2007-11-01

    A sonoelectrochemical anodization method is proposed to synthesize TiO2 nanotubular arrays on both sides of a titanium foil (TiO2/Ti/TiO2). Highly ordered TiO2 nanotubular arrays of 16 cm2 area with uniform surface distribution can be obtained using this anodization procedure. These double-sided TiO2/Ti/TiO2 materials are used as both photoanode (carbon-doped titania nanotubes) and cathode (Pt nanoparticles dispersed on TiO2 nanotubes; PtTiO2/Ti/PtTiO2) in a specially designed photoelectrochemical cell to generate hydrogen by water splitting at a rate of 38 ml h-1. The nanomaterials are characterized by FESEM, HRTEM, STEM, EDS, FFT, SAED and XPS techniques. The present approach can be used for large-scale hydrogen generation using renewable energy sources.

  4. Immobilization of Bovine Serum Albumin Upon Multiwall Carbon Nanotube for High Speed Humidity Sensing Application.

    Science.gov (United States)

    Bhattacharya, Sankhya; Sasmal, Milan

    2016-01-01

    We present a high-speed humidity sensor based on immobilization of bovine serum albumin upon multiwall carbon nanotube (IBC). A simple and versatile drop casting technique was employed to make the humidity sensor using novel material IBC at room temperature. IBC was synthesized using easy solution process technique. The working principle of the IBC humidity sensor depends upon the variation of output current or conductance with the exposure of different humidity level. Humidity sensing properties of our device is explained on the basis of charge transfer from water molecules to IBC and bovine serum albumin to multiwall carbon nanotube (MWCNT). Our sensor exhibits faster response time around 1.2 s and recovery time 1.5 s respectively.

  5. Carbon nanotubes/cobalt sulfide composites as potential high-rate and high-efficiency supercapacitors

    Science.gov (United States)

    Chen, Chia-Ying; Shih, Zih-Yu; Yang, Zusing; Chang, Huan-Tsung

    2012-10-01

    We have prepared carbon nanotube (CNT)/cobalt sulfide (CoS) composites from cobalt nitrate, thioacetamide, and CNTs in the presence of poly(vinylpyrrolidone). CNT/CoS composites are deposited onto fluorine-doped tin oxide glass substrates and then subjected to simple annealing at 300 °C for 0.5 h to fabricate CNT/CoS electrodes. Data collected from Raman spectroscopy, X-ray photoelectron spectroscopy, high-resolution transmission electron microscopy, and d-spacing reveal the changes in the CoS structures and crystalline lattices after annealing. Cyclic voltammetry results reveal that the annealed CNT/CoS composite electrodes yield values of 2140 ± 90 and 1370 ± 50 F g-1 for specific capacitance at scan rates of 10 and 100 mV s-1, respectively. To the best of our knowledge, the annealed CNT/CoS composite electrodes provide higher specific capacitance relative to other reported ones at a scan rate of 100 mV s-1. CNT/CoS composite electrodes yield a power density of 62.4 kW kg-1 at a constant discharge current density of 217.4 A g-1. With such a high-rate capacity and power density, CNT/CoS composite supercapacitors demonstrate great potential as efficient energy storage devices.

  6. Highly Conductive Aromatic Functionalized Multi-Walled Carbon Nanotube for Inkjet Printable High Performance Supercapacitor Electrodes.

    Directory of Open Access Journals (Sweden)

    Sanjeev K Ujjain

    Full Text Available We report the functionalization of multiwalled carbon nanotubes (MWCNT via the 1,3-dipolar [3+2] cycloaddition of aromatic azides, which resulted in a detangled CNT as shown by transmission electron microscopy (TEM. Carboxylic moieties (-COOH on aromatic azide result in highly stable aqueous dispersion (max. conc. ~ 10 mg/mL H2O, making the suitable for inkjet printing. Printed patterns on polyethylene terephthalate (PET flexible substrate exhibit low sheet resistivity ~65 Ω. cm, which is attributed to enhanced conductivity. Fabricated Supercapacitors (SC assembled using these printed substrates exhibit good electrochemical performance in organic as well as aqueous electrolytes. High energy and power density (57.8 Wh/kg and 0.85 kW/kg in 1M H2SO4 aqueous electrolyte demonstrate the excellent performance of the proposed supercapacitor. Capacitive retention varies from ~85-94% with columbic efficiency ~95% after 1000 charge/discharge cycles in different electrolytes, demonstrating the excellent potential of the device for futuristic power applications.

  7. Sharp burnout failure observed in high current-carrying double-walled carbon nanotube fibers

    Science.gov (United States)

    Song, Li; Toth, Geza; Wei, Jinquan; Liu, Zheng; Gao, Wei; Ci, Lijie; Vajtai, Robert; Endo, Morinobu; Ajayan, Pulickel M.

    2012-01-01

    We report on the current-carrying capability and the high-current-induced thermal burnout failure modes of 5-20 µm diameter double-walled carbon nanotube (DWNT) fibers made by an improved dry-spinning method. It is found that the electrical conductivity and maximum current-carrying capability for these DWNT fibers can reach up to 5.9 × 105 S m - 1 and over 1 × 105 A cm - 2 in air. In comparison, we observed that standard carbon fiber tended to be oxidized and burnt out into cheese-like morphology when the maximum current was reached, while DWNT fiber showed a much slower breakdown behavior due to the gradual burnout in individual nanotubes. The electron microscopy observations further confirmed that the failure process of DWNT fibers occurs at localized positions, and while the individual nanotubes burn they also get aligned due to local high temperature and electrostatic field. In addition a finite element model was constructed to gain better understanding of the failure behavior of DWNT fibers.

  8. A self-propagation high-temperature synthesis and annealing route to synthesis of wave-like boron nitride nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jilin; Zhang, Laiping [School of Materials Science and Engineering, Wuhan Institute of Technology, Wuhan, Hubei, 430073 (China); Gu, Yunle, E-mail: ncm@mail.wit.edu.cn [School of Materials Science and Engineering, Wuhan Institute of Technology, Wuhan, Hubei, 430073 (China); Pan, Xinye; Zhao, Guowei; Zhang, Zhanhui [School of Materials Science and Engineering, Wuhan Institute of Technology, Wuhan, Hubei, 430073 (China)

    2013-03-15

    Highlights: ► Large quantities of wave-like BN nanotubes were synthesized by SHS-annealing method. ► The catalytic boron-containing porous precursor was produced by self-propagation high-temperature synthesis method. ► Three growth models were proposed to explain the growth mechanism of the wave-like BN nanotubes. - Abstract: Large quantities of boron nitride (BN) nanotubes were synthesized by annealing a catalytic boron-containing porous precursor in flowing NH{sub 3} gas at 1180 °C. The porous precursor was prepared by self-propagation high-temperature synthesis (SHS) method at 800 °C using Mg, B{sub 2}O{sub 3} and amorphous boron powder (α-B) as the starting materials. The porous precursor played an important role in large quantities synthesis of BN nanotubes. The as-synthesized product was characterized by X-ray diffractometer (XRD), Fourier transform infrared spectrometer (FTIR), Raman, Scanning electron microscopy (SEM), X-ray energy dispersive spectroscopy (EDS), Transmission electron microscopy (TEM) and High-resolution transmission electron microscopy (HRTEM). Characterization results indicated that the BN nanotubes displayed wave-like inner structures with diameters in the range of 50–300 nm and average lengths of more than 10 μm. The possible growth mechanism of the BN nanotubes was also discussed.

  9. High Kinetic Energy Penetrator Shielding and High Wear Resistance Materials Fabricated with Boron Nitride Nanotubes (BNNTS) and BNNT Polymer Composites

    Science.gov (United States)

    Kang, Jin Ho (Inventor); Sauti, Godfrey (Inventor); Smith, Michael W. (Inventor); Jordan, Kevin C. (Inventor); Park, Cheol (Inventor); Bryant, Robert George (Inventor); Lowther, Sharon E. (Inventor)

    2015-01-01

    Boron nitride nanotubes (BNNTs), boron nitride nanoparticles (BNNPs), carbon nanotubes (CNTs), graphites, or combinations, are incorporated into matrices of polymer, ceramic or metals. Fibers, yarns, and woven or nonwoven mats of BNNTs are used as toughening layers in penetration resistant materials to maximize energy absorption and/or high hardness layers to rebound or deform penetrators. They can be also used as reinforcing inclusions combining with other polymer matrices to create composite layers like typical reinforcing fibers such as Kevlar.RTM., Spectra.RTM., ceramics and metals. Enhanced wear resistance and usage time are achieved by adding boron nitride nanomaterials, increasing hardness and toughness. Such materials can be used in high temperature environments since the oxidation temperature of BNNTs exceeds 800.degree. C. in air. Boron nitride based composites are useful as strong structural materials for anti-micrometeorite layers for spacecraft and space suits, ultra strong tethers, protective gear, vehicles, helmets, shields and safety suits/helmets for industry.

  10. Ilmenite Nanotubes for High Stability and High Rate Sodium-Ion Battery Anodes.

    Science.gov (United States)

    Yu, Litao; Liu, Jun; Xu, Xijun; Zhang, Liguo; Hu, Renzong; Liu, Jiangwen; Ouyang, Liuzhang; Yang, Lichun; Zhu, Min

    2017-05-23

    To solve the problem of large volume change and low electronic conductivity of earth-abundant ilmenite used in rechargeable Na-ion batteries (SIBs), an anode of tiny ilmenite FeTiO 3 nanoparticle embedded carbon nanotubes (FTO⊂CNTs) has been successfully proposed. By introducing a TiO 2 shell on metal-organic framework (Fe-MOF) nanorods by sol-gel deposition and subsequent solid-state annealing treatment of these core-shell Fe-MOF@TiO 2 , such well-defined FTO⊂CNTs are obtained. The achieved FTO⊂CNT electrode has several distinct advantages including a hollow interior in the hybrid nanostructure, fully encapsulated ultrasmall electroactive units, flexible conductive carbon matrix, and stable solid electrolyte interface (SEI) of FTO in cycles. FTO⊂CNT electrodes present an excellent cycle stability (358.8 mA h g -1 after 200 cycles at 100 mA g -1 ) and remarkable rate capability (201.8 mA h g -1 at 5000 mA g -1 ) with a high Coulombic efficiency of approximately 99%. In addition, combined with the typical Na 3 V 2 (PO 4 ) 3 cathode to constitute full SIBs, the assembled FTO⊂CNT//Na 3 V 2 (PO 4 ) 3 batteries are also demonstrated with superior rate capability and a long cycle life.

  11. Dynamics of capillary infiltration of liquids into a highly aligned multi-walled carbon nanotube film

    Directory of Open Access Journals (Sweden)

    Sławomir Boncel

    2011-06-01

    Full Text Available The physical compatibility of a highly aligned carbon nanotube (HACNT film with liquids was established using a fast and convenient experimental protocol. Two parameters were found to be decisive for the infiltration process. For a given density of nanotube packing, the thermodynamics of the infiltration process (wettability were described by the contact angle between the nanotube wall and a liquid meniscus (θ. Once the wettability criterion (θ < 90° was met, the HACNT film (of free volume equal to 91% was penetrated gradually by the liquid in a rate that can be linearly correlated to dynamic viscosity of the liquid (η. The experimental results follow the classical theory of capillarity for a steady process (Lucas–Washburn law, where the nanoscale capillary force, here supported by gravity, is compensated by viscous drag. This most general theory of capillarity can be applied in a prediction of both wettability of HACNT films and the dynamics of capillary rise in the intertube space in various technological applications.

  12. Diffusion of multiwall carbon nanotubes (MWCNTs) through a high density polyethylene (HDPE) geomembrane.

    Science.gov (United States)

    Saheli, P T; Rowe, R K; Petersen, E J; O'Carroll, D M

    2017-05-01

    The new applications for carbon nanotubes (CNTs) in various fields and consequently their greater production volume have increased their potential release to the environment. Landfills are one of the major locations where carbon nanotubes are expected to be disposed and it is important to ensure that they can limit the release of CNTs. Diffusion of multiwall carbon nanotubes (MWCNTs) dispersed in an aqueous media through a high-density polyethylene (HDPE) geomembrane (as a part of the landfill barrier system) was examined. Based on the laboratory tests, the permeation coefficient was estimated to be less than 5.1×10 -15 m 2 /s. The potential performance of a HDPE geomembrane and geosynthetic clay liner (GCL) as parts of a composite liner in containing MWCNTs was modelled for six different scenarios. The results suggest that the low value of permeation coefficient of an HDPE geomembrane makes it an effective diffusive barrier for MWCNTs and by keeping the geomembrane defects to minimum during the construction (e.g., number of holes and length of wrinkles) a composite liner commonly used in municipal solid waste landfills will effectively contain MWCNTs.

  13. Synthesis and electroplating of high resolution insulated carbon nanotube scanning probes for imaging in liquid solutions.

    Science.gov (United States)

    Roberts, N A; Noh, J H; Lassiter, M G; Guo, S; Kalinin, S V; Rack, P D

    2012-04-13

    High resolution and isolated scanning probe microscopy (SPM) is in demand for continued development of energy storage and conversion systems involving chemical reactions at the nanoscale as well as an improved understanding of biological systems. Carbon nanotubes (CNTs) have large aspect ratios and, if leveraged properly, can be used to develop high resolution SPM probes. Isolation of SPM probes can be achieved by depositing a dielectric film and selectively etching at the apex of the probe. In this paper the fabrication of a high resolution and isolated SPM tip is demonstrated using electron beam induced etching of a dielectric film deposited onto an SPM tip with an attached CNT at the apex.

  14. Use of high energy ball milling to study the role of graphene nanoplatelets and carbon nanotubes reinforced magnesium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Rashad, Muhammad, E-mail: rashadphy87@gmail.com [College of Materials Science and Engineering, Chongqing University, Chongqing 400044 (China); National Engineering Research Center for Magnesium Alloys, Chongqing University, Chongqing 400044 (China); Pan, Fusheng, E-mail: fspan@cqu.edu.cn [College of Materials Science and Engineering, Chongqing University, Chongqing 400044 (China); National Engineering Research Center for Magnesium Alloys, Chongqing University, Chongqing 400044 (China); Chongqing Academy of Science and Technology, Chongqing, Chongqing 401123 (China); Zhang, Jianyue [College of Materials Science and Engineering, Chongqing University, Chongqing 400044 (China); National Engineering Research Center for Magnesium Alloys, Chongqing University, Chongqing 400044 (China); Asif, Muhammad [School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024 (China)

    2015-10-15

    Graphene nanoplatelets (few layer graphene) and carbon nanotubes were used as reinforcement fillers to enhance the mechanical properties of AZ31 magnesium alloy through high energy ball milling, sintering, and hot extrusion techniques. Experimental results revealed that tensile fracture strain of AZ31 magnesium alloy was enhanced by +49.6% with 0.3 wt.% graphene nanoplatelets compared to −8.3% regression for 0.3 wt.% carbon nanotubes. The tensile strength of AZ31 magnesium alloy was decreased (−11.2%) with graphene nanoplatelets addition, while increased (+7.7%) with carbon nanotubes addition. Unlike tensile test, compression tests showed different trend. The compression strength of carbon nanotubes-AZ31 composite was +51.2% greater than AZ31 magnesium alloy as compared to +0.6% increase for graphene nanoplatelets. The compressive fracture strain of carbon nanotubes-AZ31 composite was decreased (−14.1%) while no significant change in fracture strain of graphene nanoplatelets-AZ31 composite was observed. The X-ray diffraction results revealed that addition of reinforcement particles weaken the basal textures which affect the composite's yield asymmetry. Microstructure evaluation revealed the absence of intermetallic phase formation between reinforcements and matrix. The carbon reinforcements in AZ31 magnesium alloy dissolve and isolate β phases throughout the matrix. The increased fracture strain and mechanical strength of graphene nanoplatelets and carbon nanotubes-AZ31 composites are attributed to large specific surface area of graphene nanoplatelets and stiffer nature of carbon nanotubes respectively. - Highlights: • Powder metallurgy method was used to fabricate magnesium composites. • The AZ31-carbon materials composite were blended using ball milling. • The reinforcement particles weaken the basal texture which affects yield asymmetry of composites. • AZ31-graphene nanoplatelets composite exhibited impressive increase in tensile elongation

  15. Use of high energy ball milling to study the role of graphene nanoplatelets and carbon nanotubes reinforced magnesium alloy

    International Nuclear Information System (INIS)

    Rashad, Muhammad; Pan, Fusheng; Zhang, Jianyue; Asif, Muhammad

    2015-01-01

    Graphene nanoplatelets (few layer graphene) and carbon nanotubes were used as reinforcement fillers to enhance the mechanical properties of AZ31 magnesium alloy through high energy ball milling, sintering, and hot extrusion techniques. Experimental results revealed that tensile fracture strain of AZ31 magnesium alloy was enhanced by +49.6% with 0.3 wt.% graphene nanoplatelets compared to −8.3% regression for 0.3 wt.% carbon nanotubes. The tensile strength of AZ31 magnesium alloy was decreased (−11.2%) with graphene nanoplatelets addition, while increased (+7.7%) with carbon nanotubes addition. Unlike tensile test, compression tests showed different trend. The compression strength of carbon nanotubes-AZ31 composite was +51.2% greater than AZ31 magnesium alloy as compared to +0.6% increase for graphene nanoplatelets. The compressive fracture strain of carbon nanotubes-AZ31 composite was decreased (−14.1%) while no significant change in fracture strain of graphene nanoplatelets-AZ31 composite was observed. The X-ray diffraction results revealed that addition of reinforcement particles weaken the basal textures which affect the composite's yield asymmetry. Microstructure evaluation revealed the absence of intermetallic phase formation between reinforcements and matrix. The carbon reinforcements in AZ31 magnesium alloy dissolve and isolate β phases throughout the matrix. The increased fracture strain and mechanical strength of graphene nanoplatelets and carbon nanotubes-AZ31 composites are attributed to large specific surface area of graphene nanoplatelets and stiffer nature of carbon nanotubes respectively. - Highlights: • Powder metallurgy method was used to fabricate magnesium composites. • The AZ31-carbon materials composite were blended using ball milling. • The reinforcement particles weaken the basal texture which affects yield asymmetry of composites. • AZ31-graphene nanoplatelets composite exhibited impressive increase in tensile elongation

  16. Nanotube cathodes.

    Energy Technology Data Exchange (ETDEWEB)

    Overmyer, Donald L.; Lockner, Thomas Ramsbeck; Siegal, Michael P.; Miller, Paul Albert

    2006-11-01

    Carbon nanotubes have shown promise for applications in many diverse areas of technology. In this report we describe our efforts to develop high-current cathodes from a variety of nanotubes deposited under a variety of conditions. Our goal was to develop a one-inch-diameter cathode capable of emitting 10 amperes of electron current for one second with an applied potential of 50 kV. This combination of current and pulse duration significantly exceeds previously reported nanotube-cathode performance. This project was planned for two years duration. In the first year, we tested the electron-emission characteristics of nanotube arrays fabricated under a variety of conditions. In the second year, we planned to select the best processing conditions, to fabricate larger cathode samples, and to test them on a high-power relativistic electron beam generator. In the first year, much effort was made to control nanotube arrays in terms of nanotube diameter and average spacing apart. When the project began, we believed that nanotubes approximately 10 nm in diameter would yield sufficient electron emission properties, based on the work of others in the field. Therefore, much of our focus was placed on measured field emission from such nanotubes grown on a variety of metallized surfaces and with varying average spacing between individual nanotubes. We easily reproduced the field emission properties typically measured by others from multi-wall carbon nanotube arrays. Interestingly, we did this without having the helpful vertical alignment to enhance emission; our nanotubes were randomly oriented. The good emission was most likely possible due to the improved crystallinity, and therefore, electrical conductivity, of our nanotubes compared to those in the literature. However, toward the end of the project, we learned that while these 10-nm-diameter CNTs had superior crystalline structure to the work of others studying field emission from multi-wall CNT arrays, these nanotubes still

  17. Nanotube cathodes

    International Nuclear Information System (INIS)

    Overmyer, Donald L.; Lockner, Thomas Ramsbeck; Siegal, Michael P.; Miller, Paul Albert

    2006-01-01

    Carbon nanotubes have shown promise for applications in many diverse areas of technology. In this report we describe our efforts to develop high-current cathodes from a variety of nanotubes deposited under a variety of conditions. Our goal was to develop a one-inch-diameter cathode capable of emitting 10 amperes of electron current for one second with an applied potential of 50 kV. This combination of current and pulse duration significantly exceeds previously reported nanotube-cathode performance. This project was planned for two years duration. In the first year, we tested the electron-emission characteristics of nanotube arrays fabricated under a variety of conditions. In the second year, we planned to select the best processing conditions, to fabricate larger cathode samples, and to test them on a high-power relativistic electron beam generator. In the first year, much effort was made to control nanotube arrays in terms of nanotube diameter and average spacing apart. When the project began, we believed that nanotubes approximately 10 nm in diameter would yield sufficient electron emission properties, based on the work of others in the field. Therefore, much of our focus was placed on measured field emission from such nanotubes grown on a variety of metallized surfaces and with varying average spacing between individual nanotubes. We easily reproduced the field emission properties typically measured by others from multi-wall carbon nanotube arrays. Interestingly, we did this without having the helpful vertical alignment to enhance emission; our nanotubes were randomly oriented. The good emission was most likely possible due to the improved crystallinity, and therefore, electrical conductivity, of our nanotubes compared to those in the literature. However, toward the end of the project, we learned that while these 10-nm-diameter CNTs had superior crystalline structure to the work of others studying field emission from multi-wall CNT arrays, these nanotubes still

  18. Synthesis of multiwall carbon nanotube wrapped Co(OH)_2 flakes: A high-performance supercapacitor

    International Nuclear Information System (INIS)

    Mondal, Chanchal; Ghosh, Debasis; Ganguly, Mainak; Sasmal, Anup Kumar; Roy, Anindita; Pal, Tarasankar

    2015-01-01

    Graphical abstract: - Highlights: • Multiwalled carbon nanotube wrapped Co(OH)_2 nanoflakes has been fabricated. • It showed high supercapcitive performance with specific capacitance of 603 F/g. • The as-prepared composite material exhibited remarkable cycling stability. • It may be applied for the development of supercapacitor electrode material. - Abstract: The problem of poor electron conductivity is always associated with pseudocapacitive electrode material that deters full utilization of the active material. To have a viable solution to this problem, we report fabrication of a composite material bringing highly conductive carbon nanotube (CNT) wrapped pseudocapacitive with Co(OH)_2 nanoflakes. An in situ growth route evolves the supercapacitor via our laboratory developed modified hydrothermal reaction condition (MHT). An electrochemical investigation substantiates that the composite material electrode is highly active, which delivers a maximum specific capacitance of 603 F g"−"1 (at 1 mV s"−"1 scan rate), outstanding long-term cyclic stability with 96% retention at a constant current density of 1.5 A g"−"1 after 1000 cycles of operation. Thus it offers almost an effortless approach to fabricate high-power and high-energy density supercapacitors. By virtue of having high-capacity of pseudocapacitive hydroxides and desirable conductivity of carbon-based materials, the as-synthesized material could be a promising candidate for the development of supercapacitor electrode material.

  19. A Combination of Boron Nitride Nanotubes and Cellulose Nanofibers for the Preparation of a Nanocomposite with High Thermal Conductivity.

    Science.gov (United States)

    Zeng, Xiaoliang; Sun, Jiajia; Yao, Yimin; Sun, Rong; Xu, Jian-Bin; Wong, Ching-Ping

    2017-05-23

    With the current development of modern electronics toward miniaturization, high-degree integration and multifunctionalization, considerable heat is accumulated, which results in the thermal failure or even explosion of modern electronics. The thermal conductivity of materials has thus attracted much attention in modern electronics. Although polymer composites with enhanced thermal conductivity are expected to address this issue, achieving higher thermal conductivity (above 10 W m -1 K -1 ) at filler loadings below 50.0 wt % remains challenging. Here, we report a nanocomposite consisting of boron nitride nanotubes and cellulose nanofibers that exhibits high thermal conductivity (21.39 W m -1 K -1 ) at 25.0 wt % boron nitride nanotubes. Such high thermal conductivity is attributed to the high intrinsic thermal conductivity of boron nitride nanotubes and cellulose nanofibers, the one-dimensional structure of boron nitride nanotubes, and the reduced interfacial thermal resistance due to the strong interaction between the boron nitride nanotubes and cellulose nanofibers. Using the as-prepared nanocomposite as a flexible printed circuit board, we demonstrate its potential usefulness in electronic device-cooling applications. This thermally conductive nanocomposite has promising applications in thermal interface materials, printed circuit boards or organic substrates in electronics and could supplement conventional polymer-based materials.

  20. Zirconium oxide nanotube-Nafion composite as high performance membrane for all vanadium redox flow battery

    Science.gov (United States)

    Aziz, Md. Abdul; Shanmugam, Sangaraju

    2017-01-01

    A high-performance composite membrane for vanadium redox flow battery (VRB) consisting of ZrO2 nanotubes (ZrNT) and perfluorosulfonic acid (Nafion) was fabricated. The VRB operated with a composite (Nafion-ZrNT) membrane showed the improved ion-selectivity (ratio of proton conductivity to permeability), low self-discharge rate, high discharge capacity and high energy efficiency in comparison with a pristine commercial Nafion-117 membrane. The incorporation of zirconium oxide nanotubes in the Nafion matrix exhibits high proton conductivity (95.2 mS cm-1) and high oxidative stability (99.9%). The Nafion-ZrNT composite membrane exhibited low vanadium ion permeability (3.2 × 10-9 cm2 min-1) and superior ion selectivity (2.95 × 107 S min cm-3). The VRB constructed with a Nafion-ZrNT composite membrane has lower self-discharge rate maintaining an open-circuit voltage of 1.3 V for 330 h relative to a pristine Nafion membrane (29 h). The discharge capacity of Nafion-ZrNT membrane (987 mAh) was 3.5-times higher than Nafion-117 membrane (280 mAh) after 100 charge-discharge cycles. These superior properties resulted in higher coulombic and voltage efficiencies with Nafion-ZrNT membranes compared to VRB with Nafion-117 membrane at a 40 mA cm-2 current density.

  1. Highly ordered Ni–Ti–O nanotubes for non-enzymatic glucose detection

    Energy Technology Data Exchange (ETDEWEB)

    Hang, Ruiqiang, E-mail: hangruiqiang@tyut.edu.cn [Research Institute of Surface Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Liu, Yanlian [Research Institute of Surface Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Gao, Ang [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China); Bai, Long; Huang, Xiaobo; Zhang, Xiangyu; Lin, Naiming [Research Institute of Surface Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Tang, Bin, E-mail: tangbin@tyut.edu.cn [Research Institute of Surface Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Chu, Paul K. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China)

    2015-06-01

    Anodization is used to fabricate Ni–Ti–O nanotube (NT) electrodes for non-enzymatic glucose detection. The morphology, microstructure and composition of the materials are characterized by field emission scanning electron microscopy (FE-SEM), high resolution transmission electron microscopy (HR-TEM) and X-ray photoelectron spectroscopy (XPS). Our results show amorphous and highly ordered NTs with diameter of 50 nm, length of 800 nm, and Ni/Ti ratio (at %) of 0.35 can be fabricated in ethylene glycol electrolyte supplemented with 0.2 wt.% NH{sub 4}F and 0.5 vol.% H{sub 2}O at 30 °C and 25 V for 1 h. Electrochemical experiments indicate that at an applied potential of 0.60 V vs. Ag/AgCl, the electrode exhibits a linear response window for glucose concentrations from 0.002 mM to 0.2 mM with a response time of 10 s, detection limit of 0.13 μM (S/N = 3), and sensitivity of 83 μA mM{sup −1} cm{sup −2}. The excellent performance of the electrode is attributed to its large specific area and fast electron transfer between the NT walls. The good electrochemical performance of the Ni–Ti–O NTs as well as their simple and low-cost preparation method make the strategy promising in non-enzymatic glucose detection. - Highlights: • Highly ordered Ni–Ti–O nanotubes have been fabricated by one-step anodization. • We find H{sub 2}O contents in the electrolyte is critical to successful fabrication of the NTs. • The Ni–Ti–O nanotubes are ideal electrode materials for non-enzymatic glucose detection.

  2. Mild hydrothermal treatment to prepare highly dispersed multi-walled carbon nanotubes

    International Nuclear Information System (INIS)

    Zhang Li; Hashimoto, Yoshio; Taishi, Toshinori; Ni Qingqing

    2011-01-01

    Multi-walled carbon nanotubes (MWCNTs) with improved dispersion property have been prepared by a mild and fast hydrothermal treatment. The hydrothermal process avoids using harsh oxidants and organic solvents, which is environmental friendly and greatly decreases the damage to intrinsic structure of MWCNTs. The modified MWCNTs were highly soluble in polar solvents such as water, ethanol and dimethylformamide. Morphological observation by TEM indicated that the diameter and inherent structure were well reserved in modified MWCNTs. X-ray photoelectron spectroscopy and Raman spectroscopy were used to quantify functional groups created on the MWCNT surface, and to determine rational parameters of hydrothermal process.

  3. High-rate capability silicon decorated vertically aligned carbon nanotubes for Li-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Gohier, Aurelien; Kim, Ki-Hwan; Maurice, Jean-Luc; Cojocaru, Costel Sorin [Laboratoire de Physique des Interfaces et des Couches Minces, LPICM, Ecole Polytechnique, route de Saclay, 91128 Palaiseau Cedex (France); Laik, Barbara; Pereira-Ramos, Jean-Pierre [Institut de Chimie et des Materiaux Paris-Est, ICMPE/GESMAT, UMR 7182 CNRS-UPEC, 2 rue Henri Dunant, 94320 Thiais (France); Van, Pierre Tran [Renault SAS, DREAM/DETA/SEE, 1, avenue du Golf, 78288 Guyancourt (France)

    2012-05-15

    The concept of a hybrid nanostructured collector made of thin vertically aligned carbon nanotubes (CNTs) decorated with Si nanoparticles provides high power density anodes in lithium-ion batteries. An impressive rate capability is achieved due to the efficient electronic conduction of CNTs combined with well defined electroactive Si nanoparticles: capacities of 3000 mAh g{sup -1} at 1.3C and 800 mAh g{sup -1} at 15C are achieved. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  4. Azobenzene-functionalized carbon nanotubes as high-energy density solar thermal fuels.

    Science.gov (United States)

    Kolpak, Alexie M; Grossman, Jeffrey C

    2011-08-10

    Solar thermal fuels, which reversibly store solar energy in molecular bonds, are a tantalizing prospect for clean, renewable, and transportable energy conversion/storage. However, large-scale adoption requires enhanced energy storage capacity and thermal stability. Here we present a novel solar thermal fuel, composed of azobenzene-functionalized carbon nanotubes, with the volumetric energy density of Li-ion batteries. Our work also demonstrates that the inclusion of nanoscale templates is an effective strategy for design of highly cyclable, thermally stable, and energy-dense solar thermal fuels.

  5. Growth and characterization of BCN nanotubes with high boron and ...

    Indian Academy of Sciences (India)

    ties provide BCNTs great potential for application in electronics,10 ... nanodevice applications where high-strength and .... glass carbon to measure their NO electro-oxidation .... binding energies of 398.2 eV can be assigned to the N atoms in ...

  6. High-Performance Ttransparent and Stretchable All-Solid Supercapacitors Based on Highly Aligned Carbon Nanotube Sheets

    Science.gov (United States)

    2014-01-09

    supercapacitors based on poly ( ionic liquid )- modified graphene electrodes. ACS Nano 5, 436–442 (2011). 34. Denisa, H.-J. et al. Highly stable performance of...Niu, Z. et al. A repeated halving approach to fabricate ultrathin single-walled carbon nanotube films for transparent supercapacitors. Small 9, 518–524...PVA-H3PO4/CNT/PDMS multilayer film in either a parallel (Figure 1b) or cross (Figure 1c) configuration, leading to highly transparent devices to be

  7. High-yield Synthesis of Multiwalled Carbon Nanotube by Mechanothermal Method

    Directory of Open Access Journals (Sweden)

    Manafi SA

    2009-01-01

    Full Text Available Abstract This study reports on the mechanothermal synthesis of multiwalled carbon nanotube (MWCNTs from elemental graphite powder. Initially, high ultra-active graphite powder can be obtained by mechanical milling under argon atmosphere. Finally, the mechanical activation product is heat-treated at 1350°C for 2–4 h under argon gas flow. After heat-treatment, active graphite powders were successfully changed into MWCNTs with high purity. The XRD analyses showed that in the duration 150 h of milling, all the raw materials were changed to the desired materials. From the broadening of the diffraction lines in the XRD patterns, it was concluded that the graphite crystallites were nanosized, and raising the milling duration resulted in the fineness of the particles and the increase of the strain. The structure and morphology of MWCNTs were investigated using scanning electron microscopy (SEM and high-resolution transmission electron microscopy (HRTEM. The yield of MWCNTs was estimated through SEM and TEM observations of the as-prepared samples was to be about 90%. Indeed, mechanothermal method is of interest for fundamental understanding and improvement of commercial synthesis of carbon nanotubes (CNTs. As a matter of fact, the method of mechanothermal guarantees the production of MWCNTs suitable for different applications.

  8. Adhesion measurement of highly-ordered TiO2 nanotubes on Ti-6Al-4V alloy

    Directory of Open Access Journals (Sweden)

    Masoud Sarraf

    2017-12-01

    Full Text Available Self-assembled nanotubular arrays on Ti alloys could be used for more effective implantable devices in various medical approaches. In the present work, the adhesion of TiO2 nanotubes (TiO2 NTs on Ti-6Al-4V (Ti64 was investigated by laser spallation and scratch test techniques. At first, electrochemical anodization was performed in an ammonium fluoride solution dissolved in a 90:10 ethane-1,2-diol (ethylene glycol and water solvent mixture. This process was performed at room temperature (23 °C at a steady potential of 60 V for 1 h. Next, the TiO2 nanotubes layer was heat-treated to improve the adhesion of the coating. The formation of selforganized TiO2 nanotubes as well as the microstructural evolution, are strongly dependent on the processing parameters and subsequent annealing. From microscopic analysis, highly oriented arrays of TiO2 nanotubes were grown by thermal treatment for 90 min at 500 °C. Further heat treatment above 500 °C led to the detachment of the nanotubes and the complete destruction of the nanotubes occurred at temperature above 700 °C. Scratch test analysis over a constant scratch length (1000 µm indicated that the failure point was shifted from 247.4 to 557.9 µm while the adhesion strength was increased from ∼862 to ∼1814 mN after annealing at 500 °C. The adhesion measurement determined by laser spallation technique provided an intrinsic adhesion strength of 51.4 MPa for the TiO2 nanotubes on the Ti64 substrate.

  9. Industrial-scale separation of high-purity single-chirality single-wall carbon nanotubes for biological imaging

    Science.gov (United States)

    Yomogida, Yohei; Tanaka, Takeshi; Zhang, Minfang; Yudasaka, Masako; Wei, Xiaojun; Kataura, Hiromichi

    2016-01-01

    Single-chirality, single-wall carbon nanotubes are desired due to their inherent physical properties and performance characteristics. Here, we demonstrate a chromatographic separation method based on a newly discovered chirality-selective affinity between carbon nanotubes and a gel containing a mixture of the surfactants. In this system, two different selectivities are found: chiral-angle selectivity and diameter selectivity. Since the chirality of nanotubes is determined by the chiral angle and diameter, combining these independent selectivities leads to high-resolution single-chirality separation with milligram-scale throughput and high purity. Furthermore, we present efficient vascular imaging of mice using separated single-chirality (9,4) nanotubes. Due to efficient absorption and emission, blood vessels can be recognized even with the use of ∼100-fold lower injected dose than the reported value for pristine nanotubes. Thus, 1 day of separation provides material for up to 15,000 imaging experiments, which is acceptable for industrial use. PMID:27350127

  10. Novel catalytic route to bulk production of high purity carbon nanotube

    International Nuclear Information System (INIS)

    Dasgupta, Kinshuk; Venugopalan, Ramani; Dey, G. K.; Sathiyamoorthy, D.

    2008-01-01

    Carbon nanotubes have been synthesized by catalytic chemical vapour deposition of acetylene diluted with argon using three different catalysts, namely, nickel formate, cobalt formate and ferrocene. The synthesis was carried out at 700 deg. C in a quartz reactor for 30 minutes. Thermal analysis was carried out in order to determine the yield of the nanotube. It was found that the deposit contains 86% nanotube, with nickel-based catalyst, which was the maximum. The yield of nanotube was 71 times that of the nickel loading. The TEM images reveal helical type of nanotubes with iron catalyst while cobalt and nickel catalysts yielded straight nanotubes. This technique can be explored for the bulk production of carbon nanotube in an economic way

  11. Three-dimensional carbon nanotube networks with a supported nickel oxide nanonet for high-performance supercapacitors.

    Science.gov (United States)

    Wu, Mao-Sung; Zheng, Yo-Ru; Lin, Guan-Wei

    2014-08-04

    A three-dimensional porous carbon nanotube film with a supported NiO nanonet was prepared by simple electrophoretic deposition and hydrothermal synthesis, which could deliver a high specific capacitance of 1511 F g(-1) at a high discharge current of 50 A g(-1) due to the significantly improved transport of the electrolyte and electrons.

  12. High performance electrochemical and electrothermal artificial muscles from twist-spun carbon nanotube yarn

    Science.gov (United States)

    Lee, Jae Ah; Baughman, Ray H.; Kim, Seon Jeong

    2015-04-01

    High performance torsional and tensile artificial muscles are described, which utilize thermally- or electrochemically-induced volume changes of twist-spun, guest-filled, carbon nanotube (CNT) yarns. These yarns were prepared by incorporating twist in carbon nanotube sheets drawn from spinnable CNT forests. Inserting high twist into the CNT yarn results in yarn coiling, which can dramatically amplify tensile stroke and work capabilities compared with that for the non-coiled twisted yarn. When electrochemically driven in a liquid electrolyte, these artificial muscles can generate a torsional rotation per muscle length that is over 1000 times higher than for previously reported torsional muscles. All-solid-state torsional electrochemical yarn muscles have provided a large torsional muscle stroke (53° per mm of yarn length) and a tensile stroke of up to 1.3% when lifting loads that are ~25 times heavier than can be lifted by the same diameter human skeletal muscle. Over a million torsional and tensile actuation cycles have been demonstrated for thermally powered CNT hybrid yarns muscles filled with paraffin wax, wherein a muscle spins a rotor at an average 11,500 revolutions/minute or delivers 3% tensile contraction at 1200 cycles/minute. At lower actuation rates, these thermally powered muscles provide tensile strokes of over 10%.

  13. Graphene and carbon nanotube composite electrodes for supercapacitors with ultra-high energy density.

    Science.gov (United States)

    Cheng, Qian; Tang, Jie; Ma, Jun; Zhang, Han; Shinya, Norio; Qin, Lu-Chang

    2011-10-21

    We describe a graphene and single-walled carbon nanotube (SWCNT) composite film prepared by a blending process for use as electrodes in high energy density supercapacitors. Specific capacitances of 290.6 F g(-1) and 201.0 F g(-1) have been obtained for a single electrode in aqueous and organic electrolytes, respectively, using a more practical two-electrode testing system. In the organic electrolyte the energy density reached 62.8 Wh kg(-1) and the power density reached 58.5 kW kg(-1). The addition of single-walled carbon nanotubes raised the energy density by 23% and power density by 31% more than the graphene electrodes. The graphene/CNT electrodes exhibited an ultra-high energy density of 155.6 Wh kg(-1) in ionic liquid at room temperature. In addition, the specific capacitance increased by 29% after 1000 cycles in ionic liquid, indicating their excellent cyclicity. The SWCNTs acted as a conductive additive, spacer, and binder in the graphene/CNT supercapacitors. This work suggests that our graphene/CNT supercapacitors can be comparable to NiMH batteries in performance and are promising for applications in hybrid vehicles and electric vehicles. This journal is © the Owner Societies 2011

  14. Synergistic fusion of vertical graphene nanosheets and carbon nanotubes for high-performance supercapacitor electrodes.

    Science.gov (United States)

    Seo, Dong Han; Yick, Samuel; Han, Zhao Jun; Fang, Jing Hua; Ostrikov, Kostya Ken

    2014-08-01

    Graphene and carbon nanotubes (CNTs) are attractive electrode materials for supercapacitors. However, challenges such as the substrate-limited growth of CNTs, nanotube bundling in liquid electrolytes, under-utilized basal planes, and stacking of graphene sheets have so far impeded their widespread application. Here we present a hybrid structure formed by the direct growth of CNTs onto vertical graphene nanosheets (VGNS). VGNS are fabricated by a green plasma-assisted method to break down and reconstruct a natural precursor into an ordered graphitic structure. The synergistic combination of CNTs and VGNS overcomes the challenges intrinsic to both materials. The resulting VGNS/CNTs hybrids show a high specific capacitance with good cycling stability. The charge storage is based mainly on the non-Faradaic mechanism. In addition, a series of optimization experiments were conducted to reveal the critical factors that are required to achieve the demonstrated high supercapacitor performance. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. A stable high-speed rotational transmission system based on nanotubes

    International Nuclear Information System (INIS)

    Cai, Kun; Yin, Hang; Wei, Ning; Chen, Zhen; Shi, Jiao

    2015-01-01

    A stable rotational transmission system is designed with a single-walled carbon nanotube (SWCNT)-based motor and double-walled carbon nanotubes (DWCNTs)-based bearing. The system response is investigated using molecular dynamics (MD) simulation. It is found that the rotating motor can actuate the rotation of the inner tube in bearing because of the attraction between the two adjacent coaxial ends of motor and rotor (the inner tube in bearing). To have a stable nanostructure, each carbon atom on the adjacent ends of motor and rotor is bonded with a hydrogen atom. To obtain a stable high-speed rotational transmission system, both an armchair and a zigzag model are used in MD simulation. In each model, the motor with different diameters and rotational speeds is employed to examine the rotational transmission of corresponding DWCNTs. It is demonstrated that the long range van der Waals interaction between the adjacent ends of motor and rotor leads to a stable configuration of the adjacent ends, and further leads to a stable rotation of rotor when driven by a high-speed motor. As compared with the armchair model, the rotor in the zigzag model could reach a stable rotation mode much easier

  16. thesis of high-purity carbon nanotubes over alumina and silica supported bimetallic catalysts

    Directory of Open Access Journals (Sweden)

    Sanja Ratković

    2009-10-01

    Full Text Available Carbon nanotubes (CNTs were synthesized by a catalytic chemical vapor deposition method (CCVD of ethylene over alumina and silica supported bimetallic catalysts based on Fe, Co and Ni. The catalysts were prepared by a precipitation method, calcined at 600 °C and in situ reduced in hydrogen flow at 700 °C. The CNTs growth was carried out by a flow the mixture of C2H4 and nitrogen over the catalyst powder in a horizontal oven. The structure and morphology of as-synthesized CNTs were characterized using SEM. The as-synthesized nanotubes were purified by acid and basic treatments in order to remove impurities such as amorphous carbon, graphite nanoparticles and metal catalysts. XRD and DTA/TG analyses showed that the amounts of by-products in the purified CNTs samples were reduced significantly. According to the observed results, ethylene is an active carbon source for growing high-density CNTs with high yield but more on alumina-supported catalysts than on their silica- supported counterparts. The last might be explained by SMSI formed in the case of alumina-supported catalysts, resulting in higher active phase dispersion.

  17. Synthesis of highly-ordered TiO2 nanotube arrays with tunable sizes

    Science.gov (United States)

    Wang, Xian; Zha, Chenyang; Ji, Cheng; Zhang, Xiaoyan; Shen, Liming; Wang, Yifeng; Gupta, Arunava; Yoriya, Sorachon; Bao, Ningzhong

    2014-09-01

    Vertically-oriented one-dimensional TiO2 nanotube (TNT) arrays have been fabricated by anodic oxidation using different electrolyte solvents, including ethylene glycol (EG), diethylene glycol (DEG), and dimethyl sulfoxide (DMSO), in the presence of hydrofluoric acid (HF) or ammonium fluoride (NH4F). The influence of synthetic conditions, including the nature of the electrolyte and anodization voltage, on nanotube microstructure has been systematically investigated. Highly-ordered TNTs with tube length of ˜0.5-26.7 μm, inner diameter of ˜13-201 nm, and outer diameter of ˜28-250 nm have been obtained. The conversion of as-prepared TNT arrays from amorphous phase to crystalline structure has been achieved by a post-synthetic annealing at 500 °C for 3 h in oxygen ambient. The TNT arrays with tunable sizes and structures are attractive for use as electrode materials in fabrication of thin film solar cells and highly active photocatalysts.

  18. Synthesis of highly-ordered TiO2 nanotube arrays with tunable sizes

    International Nuclear Information System (INIS)

    Wang, Xian; Zha, Chenyang; Ji, Cheng; Zhang, Xiaoyan; Shen, Liming; Wang, Yifeng; Bao, Ningzhong; Gupta, Arunava; Yoriya, Sorachon

    2014-01-01

    Vertically-oriented one-dimensional TiO 2 nanotube (TNT) arrays have been fabricated by anodic oxidation using different electrolyte solvents, including ethylene glycol (EG), diethylene glycol (DEG), and dimethyl sulfoxide (DMSO), in the presence of hydrofluoric acid (HF) or ammonium fluoride (NH 4 F). The influence of synthetic conditions, including the nature of the electrolyte and anodization voltage, on nanotube microstructure has been systematically investigated. Highly-ordered TNTs with tube length of ∼0.5–26.7 μm, inner diameter of ∼13–201 nm, and outer diameter of ∼28–250 nm have been obtained. The conversion of as-prepared TNT arrays from amorphous phase to crystalline structure has been achieved by a post-synthetic annealing at 500 °C for 3 h in oxygen ambient. The TNT arrays with tunable sizes and structures are attractive for use as electrode materials in fabrication of thin film solar cells and highly active photocatalysts. (paper)

  19. Fabrication of graphene foam supported carbon nanotube/polyaniline hybrids for high-performance supercapacitor applications

    International Nuclear Information System (INIS)

    Yang, Hongxia; Wang, Nan; Xu, Qun; Chen, Zhimin; Ren, Yumei; Razal, Joselito M; Chen, Jun

    2014-01-01

    A large-scale, high-powered energy storage system is crucial for addressing the energy problem. The development of high-performance materials is a key issue in realizing the grid-scale applications of energy-storage devices. In this work, we describe a simple and scalable method for fabricating hybrids (graphene-pyrrole/carbon nanotube-polyaniline (GPCP)) using graphene foam as the supporting template. Graphene-pyrrole (G-Py) aerogels are prepared via a green hydrothermal route from two-dimensional materials such as graphene sheets, while a carbon nanotube/polyaniline (CNT/PANI) composite dispersion is obtained via the in situ polymerization method. The functional nanohybrid materials of GPCP can be assembled by simply dipping the prepared G-py aerogels into the CNT/PANI dispersion. The morphology of the obtained GPCP is investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), which revealed that the CNT/PANI was uniformly deposited onto the surfaces of the graphene. The as-synthesized GPCP maintains its original three-dimensional hierarchical porous architecture, which favors the diffusion of the electrolyte ions into the inner region of the active materials. Such hybrid materials exhibit significant specific capacitance of up to 350 F g −1 , making them promising in large-scale energy-storage device applications. (paper)

  20. Ultra-high density aligned Carbon-nanotube with controled nano-morphology for supercapacitors

    Science.gov (United States)

    Ghaffari, Mehdi; Zhao, Ran; Liu, Yang; Zhou, Yue; Cheng, Jiping; Guzman de Villoria, Roberto; Wardle, B. L.; Zhang, Q. M.

    2012-02-01

    Recent advances in fabricating controlled-morphology vertically aligned carbon nanotubes (VA-CNTs) with ultrahigh volume fractioncreate unique opportunities for developing unconventional supercapacitors with ultra-high energy density, power density, and long charge/discharge cycle life.Continuous paths through inter-VA-CNT channels allow fast ion transport, and high electrical conduction of the aligned CNTs in the composite electrodes lead to fast discharge speed. We investigate the charge-discharge characteristics of VA-CNTs with >20 vol% of CNT and ionic liquids as electrolytes. By employing both the electric and electromechanical spectroscopes, as well as nanostructured materials characterization, the ion transport and storage behaviors in porous electrodes are studied. The results suggest pathways for optimizing the electrode morphology in supercapacitorsusing ultra-high volume fraction VA-CNTs to further enhance performance.

  1. A Flexible and Highly Sensitive Piezoresistive Pressure Sensor Based on Micropatterned Films Coated with Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Jia-lin Yao

    2016-01-01

    Full Text Available Excellent flexibility, high sensitivity, and low consumption are essential characteristics in flexible microtube pressure sensing occasion, for example, implantable medical devices, industrial pipeline, and microfluidic chip. This paper reports a flexible, highly sensitive, and ultrathin piezoresistive pressure sensor for fluid pressure sensing, whose sensing element is micropatterned films with conductive carbon nanotube layer. The flexible pressure sensor, the thickness of which is 40 ± 10 μm, could be economically fabricated by using biocompatible polydimethylsiloxane (PDMS. Experimental results show that the flexible pressure sensor has high sensitivity (0.047 kPa−1 in gas sensing and 5.6 × 10−3 kPa−1 in liquid sensing and low consumption (<180 μW, and the sensor could be used to measure the pressure in curved microtubes.

  2. High-performance supercapacitors using a nanoporous current collector made from super-aligned carbon nanotubes

    Science.gov (United States)

    Zhou, Ruifeng; Meng, Chuizhou; Zhu, Feng; Li, Qunqing; Liu, Changhong; Fan, Shoushan; Jiang, Kaili

    2010-08-01

    Nanoporous current collectors for supercapacitors have been fabricated by cross-stacking super-aligned carbon nanotube (SACNT) films as a replacement for heavy conventional metallic current collectors. The CNT-film current collectors have good conductivity, extremely low density (27 µg cm - 2), high specific surface area, excellent flexibility and good electrochemical stability. Nanosized active materials such as NiO, Co3O4 or Mn2O3 nanoparticles can be directly synthesized on the SACNT films by a straightforward one-step, in situ decomposition strategy that is both efficient and environmentally friendly. These composite films can be integrated into a pseudo-capacitor that does not use metallic current collectors, but nevertheless shows very good performance, including high specific capacitance (~500 F g - 1, including the current collector mass), reliable electrochemical stability (<4.5% degradation in 2500 cycles) and a very high rate capability (245 F g - 1 at 155 A g - 1).

  3. Preparation and Characterization of Highly Aligned Carbon Nanotubes/Polyacrylonitrile Composite Nanofibers

    Directory of Open Access Journals (Sweden)

    Yanhua Song

    2017-01-01

    Full Text Available In the electrospinning process, a modified parallel electrode method (MPEM, conducted by placing a positively charged ring between the needle and the parallel electrode collector, was used to fabricate highly aligned carbon nanotubes/polyacrylonitrile (CNTs/PAN composite nanofibers. Characterizations of the samples—such as morphology, the degree of alignment, and mechanical and conductive properties—were investigated by a combination of scanning electron microscopy (SEM, transmission electron microscopy (TEM, universal testing machine, high-resistance meter, and other methods. The results showed the MPEM could improve the alignment and uniformity of electrospun CNTs/PAN composite nanofibers, and enhance their mechanical and conductive properties. This meant the successful preparation of highly aligned CNT-reinforced PAN nanofibers with enhanced physical properties, suggesting their potential application in appliances and communication areas.

  4. Theoretical prediction of high carrier mobility in single-walled black phosphorus nanotubes

    Science.gov (United States)

    Li, Q. F.; Wang, H. F.; Yang, C. H.; Li, Q. Q.; Rao, W. F.

    2018-05-01

    One-dimensional semiconductors are promising materials for high-performance nanoscale devices. Using the first-principles calculations combined with deformation potential approximation, we study the electronic structures and carrier transport properties of black phosphorus nanotubes (BPNTs). It is found that both armchair and zigzag BPNTs with diameter 13.5-18.5 Å are direct bandgap semiconductors. At a similar diameter, the carrier mobility of zigzag BPNT is one order of magnitude larger than that of armchair BPNT. For armchair BPNTs, the electron mobility is about 90.70-155.33 cm2 V-1 s-1 at room temperature, which is about three times of its hole counterpart. For zigzag BPNTs, the maximum mobility can reach 2.87 ×103 cm2 V-1 s-1. Furthermore, the electronic properties can be effectively tuned by the strain. For zigzag (0,13) nanotube, there is a direct-to-indirect band gap transition at a tensile strain of about 6%. Moreover, the electron mobility is boosted sharply by one order of magnitude by applying the compressive or tensile strain. The electron mobility increases to 14.05 ×103 cm2 V-1 s-1 at a tensile strain of 9%. Our calculations highlight the tunable electronic properties and superior carrier mobility of BPNTs that are promising for interesting applications in future nano-electronic devices.

  5. Feshbach shape resonance for high Tc superconductivity in superlattices of nanotubes

    International Nuclear Information System (INIS)

    Bianconi, Antonio

    2006-01-01

    The case of a Feshbach shape resonance in the pairing mechanism for high T c superconductivity in a crystalline lattice of doped metallic nanotubes is described. The superlattice of doped metallic nanotubes provides a superconductor with a strongly asymmetric gap. The disparity and different spatial locations of the wave functions of electrons in different subbands at the Fermi level should suppress the single electron impurity interband scattering giving multiband superconductivity in the clean limit. The Feshbach resonances will arise from the component single-particle wave functions out of which the electron pair wave function is constructed: pairs of wave functions which are time inverse of each other. The Feshbach shape resonance increases the critical temperature by tuning the chemical potential at the Lifshitz electronic topological transition (ETT) where the Fermi surface of one of the bands changes from the one dimensional (1D) to the two dimensional (2D) topology (1D/2D ETT). (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (Abstract Copyright [2006], Wiley Periodicals, Inc.)

  6. Polymer-Sorted Semiconducting Carbon Nanotube Networks for High-Performance Ambipolar Field-Effect Transistors

    Science.gov (United States)

    2014-01-01

    Efficient selection of semiconducting single-walled carbon nanotubes (SWNTs) from as-grown nanotube samples is crucial for their application as printable and flexible semiconductors in field-effect transistors (FETs). In this study, we use atactic poly(9-dodecyl-9-methyl-fluorene) (a-PF-1-12), a polyfluorene derivative with asymmetric side-chains, for the selective dispersion of semiconducting SWNTs with large diameters (>1 nm) from plasma torch-grown SWNTs. Lowering the molecular weight of the dispersing polymer leads to a significant improvement of selectivity. Combining dense semiconducting SWNT networks deposited from an enriched SWNT dispersion with a polymer/metal-oxide hybrid dielectric enables transistors with balanced ambipolar, contact resistance-corrected mobilities of up to 50 cm2·V–1·s–1, low ohmic contact resistance, steep subthreshold swings (0.12–0.14 V/dec) and high on/off ratios (106) even for short channel lengths (<10 μm). These FETs operate at low voltages (<3 V) and show almost no current hysteresis. The resulting ambipolar complementary-like inverters exhibit gains up to 61. PMID:25493421

  7. Functional Carbon Nanotube/Mesoporous Carbon/MnO2 Hybrid Network for High-Performance Supercapacitors

    Directory of Open Access Journals (Sweden)

    Tao Tao

    2014-01-01

    Full Text Available A functional carbon nanotube/mesoporous carbon/MnO2 hybrid network has been developed successfully through a facile route. The resulting composites exhibited a high specific capacitance of 351 F/g at 1 A g−1, with intriguing charge/discharge rate performance and cycling stability due to a synergistic combination of large surface area and excellent electron-transport capabilities of MnO2 with the good conductivity of the carbon nanotube/mesoporous carbon networks. Such composite shows great potential to be used as electrodes for supercapacitors.

  8. Au nanoparticles attached carbon nanotubes as a high performance active element in field effect transistor

    International Nuclear Information System (INIS)

    Lee, Myeongsoon; Kim, Don

    2016-01-01

    The Au nanoparticles attached carbon nanotubes (Au-CNTs), diameter ranged from 40 to 250 nm, were prepared and discussed their chemical and electrical properties. The shape and crystallinity of the carbon nanotubes (CNTs) phase depended main2ly on the diameter of CNTs (r_A_u_-_C_N_T). Highly crystalline, straight CNTs were observed when the r_A_u_-_C_N_T exceeded 80 nm, and less crystalline noodle-shaped CNTs were observed when the r_A_u_-_C_N_T was smaller than 80 nm. The crystallinity of the CNT phase was confirmed by analyzing the G and D bands in their Raman spectra and the electrical conductivities of the Au-CNTs. The electrical conductivity of the highly crystalline carbon phase of Au-CNTs (r_A_u_-_C_N_T = 250 nm) was ∼10"4 S/cm. The back-gated field effect transistors (FETs) based on the Au-CNTs, which were assembled on a SiO_2/Si wafer using the dielectrophoresis technique, showed that the Au-CNTs would be a good functional electronic material for future electronic and sensing applications. The transconductance and hole mobility of the FETs, which were assembled with the highly crystalline Au-CNTs (r_A_u_-_C_N_T = 250 nm), reached to 3.6 × 10"−"4 A/V and 3.1 × 10"4 cm"2/V s, respectively. These values are in the middle of those of reported for single walled carbon nanotubes and graphene. However, we could not find any field effect in a CNTFET, which assembled without Au nanoparticles, through the same process. - Highlights: • The shape and crystallinity of the CNTs depended mainly on the diameter of CNTs. • The electrical conductivity of the highly crystalline Au-CNTs was ∼10"4 S/cm. • The Au-CNT FET shows typical p-channel gate effect with the on/off ratio of ∼10"4. • The Au-CNT FET shows very high transconductance (g_m) and carrier mobility (μ_h).

  9. Au nanoparticles attached carbon nanotubes as a high performance active element in field effect transistor

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Myeongsoon; Kim, Don, E-mail: donkim@pknu.ac.kr

    2016-08-15

    The Au nanoparticles attached carbon nanotubes (Au-CNTs), diameter ranged from 40 to 250 nm, were prepared and discussed their chemical and electrical properties. The shape and crystallinity of the carbon nanotubes (CNTs) phase depended main2ly on the diameter of CNTs (r{sub Au-CNT}). Highly crystalline, straight CNTs were observed when the r{sub Au-CNT} exceeded 80 nm, and less crystalline noodle-shaped CNTs were observed when the r{sub Au-CNT} was smaller than 80 nm. The crystallinity of the CNT phase was confirmed by analyzing the G and D bands in their Raman spectra and the electrical conductivities of the Au-CNTs. The electrical conductivity of the highly crystalline carbon phase of Au-CNTs (r{sub Au-CNT} = 250 nm) was ∼10{sup 4} S/cm. The back-gated field effect transistors (FETs) based on the Au-CNTs, which were assembled on a SiO{sub 2}/Si wafer using the dielectrophoresis technique, showed that the Au-CNTs would be a good functional electronic material for future electronic and sensing applications. The transconductance and hole mobility of the FETs, which were assembled with the highly crystalline Au-CNTs (r{sub Au-CNT} = 250 nm), reached to 3.6 × 10{sup −4} A/V and 3.1 × 10{sup 4} cm{sup 2}/V s, respectively. These values are in the middle of those of reported for single walled carbon nanotubes and graphene. However, we could not find any field effect in a CNTFET, which assembled without Au nanoparticles, through the same process. - Highlights: • The shape and crystallinity of the CNTs depended mainly on the diameter of CNTs. • The electrical conductivity of the highly crystalline Au-CNTs was ∼10{sup 4} S/cm. • The Au-CNT FET shows typical p-channel gate effect with the on/off ratio of ∼10{sup 4}. • The Au-CNT FET shows very high transconductance (g{sub m}) and carrier mobility (μ{sub h}).

  10. High-density carbon nanotube wet-laid buckypapers with enhanced strength and conductivity using a high-pressure homogenization process

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Jun; Jang, Si Hoon; Park, No Hyung; Jeong, Won Young; Lim, Dae Young [Human and Culture Convergence Technology Group, Korea Institute of Industrial Technology (KITECH), Ansan (Korea, Republic of); Oh, Jun Young; Yang, Seung Jae [Dept. of Applied Organic Materials Engineering, Inha University, Incheon (Korea, Republic of)

    2017-04-15

    In this work, we prepared homogeneously dispersed carbon nanotubes in water using a high-pressure homogenizer, while high-density carbon nanotube buckypapers were prepared by wet-laid process. The strength and conductivity of the buckypaper were increased dramatically after the high-pressure homogenization because of the increased density and uniformity of the paper. In addition, the buckypapers containing various additives and treated with SOCl{sub 2} exhibited further increase of strength and conductivity resulting from the binding and the p-type doping effect. The buckypapers with high electrical conductivity exhibited superior electromagnetic interference shielding effectiveness that could be applied for structural shielding materials.

  11. Highly Stretchable Supercapacitors Based on Aligned Carbon Nanotube/Molybdenum Disulfide Composites.

    Science.gov (United States)

    Lv, Tian; Yao, Yao; Li, Ning; Chen, Tao

    2016-08-01

    Stretchable supercapacitors that can sustain their performance under unpredictable tensile force are important elements for practical applications of various portable and wearable electronics. However, the stretchability of most reported supercapacitors was often lower than 100 % because of the limitation of the electrodes used. Herein we developed all-solid-state supercapacitors with a stretchability as high as 240 % by using aligned carbon nanotube composites with compact structure as electrodes. By combined with pseudocapacitive molybdenum disulfide nanosheets, the newly developed supercapacitor showed a specific capacitance of 13.16 F cm(-3) , and also showed excellent cycling retention (98 %) after 10 000 charge-discharge cycles. This work also presents a general and effective approach in developing high-performance electrodes for flexible and stretchable electronics. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Highly sensitive strain sensors based on fragmentized carbon nanotube/polydimethylsiloxane composites

    Science.gov (United States)

    Gao, Yang; Fang, Xiaoliang; Tan, Jianping; Lu, Ting; Pan, Likun; Xuan, Fuzhen

    2018-06-01

    Wearable strain sensors based on nanomaterial/elastomer composites have potential applications in flexible electronic skin, human motion detection, human–machine interfaces, etc. In this research, a type of high performance strain sensors has been developed using fragmentized carbon nanotube/polydimethylsiloxane (CNT/PDMS) composites. The CNT/PDMS composites were ground into fragments, and a liquid-induced densification method was used to fabricate the strain sensors. The strain sensors showed high sensitivity with gauge factors (GFs) larger than 200 and a broad strain detection range up to 80%, much higher than those strain sensors based on unfragmentized CNT/PDMS composites (GF composite particles during mechanical deformation, which causes significant resistance change in the strain sensors. The strain sensors can differentiate mechanical stimuli and monitor various human body motions, such as bending of the fingers, human breathing, and blood pulsing.

  13. High-efficiency supercapacitor electrodes of CVD-grown graphenes hybridized with multiwalled carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Kalam, Amir Abul; Bae, Joon Ho [Dept. of Nano-physics, Gachon University, Seongnam (Korea, Republic of); Park, Soo Bin; Seo, Yong Ho [Nanotechnology and Advanced Material Engineering, HMC, and GRI, Sejong University, Seoul (Korea, Republic of)

    2015-08-15

    We demonstrate, for the first time, high-efficiency supercapacitors by utilizing chemical vapor deposition (CVD)-grown graphenes hybridized with multiwalled carbon nanotubes (CNTs). A single-layer graphene was grown by simple CVD growth method, and transferred to polyethylene terephthalate substrates. The bare graphenes were further hybridized with multiwalled CNTs by drop-coating CNTs on graphenes. The supercapacitors using bare graphenes and graphenes with CNTs revealed that graphenes with CNTs resulted in enhanced supercapacitor performances of 2.2- (the mass-specific capacitance) and 4.4-fold (the area-specific capacitance) of those of bare graphenes. Our strategy to improve electrochemical performance of CVD-grown graphenes is advantageous for large-scale graphene electrodes due to high electrical conductivity of CVD-grown graphenes and cost-effectiveness of using multiwalled CNTs as compared to conventional employment of single-walled CNTs.

  14. High-efficiency supercapacitor electrodes of CVD-grown graphenes hybridized with multiwalled carbon nanotubes

    International Nuclear Information System (INIS)

    Kalam, Amir Abul; Bae, Joon Ho; Park, Soo Bin; Seo, Yong Ho

    2015-01-01

    We demonstrate, for the first time, high-efficiency supercapacitors by utilizing chemical vapor deposition (CVD)-grown graphenes hybridized with multiwalled carbon nanotubes (CNTs). A single-layer graphene was grown by simple CVD growth method, and transferred to polyethylene terephthalate substrates. The bare graphenes were further hybridized with multiwalled CNTs by drop-coating CNTs on graphenes. The supercapacitors using bare graphenes and graphenes with CNTs revealed that graphenes with CNTs resulted in enhanced supercapacitor performances of 2.2- (the mass-specific capacitance) and 4.4-fold (the area-specific capacitance) of those of bare graphenes. Our strategy to improve electrochemical performance of CVD-grown graphenes is advantageous for large-scale graphene electrodes due to high electrical conductivity of CVD-grown graphenes and cost-effectiveness of using multiwalled CNTs as compared to conventional employment of single-walled CNTs

  15. Highly sensitive strain sensors based on fragmentized carbon nanotube/polydimethylsiloxane composites.

    Science.gov (United States)

    Gao, Yang; Fang, Xiaoliang; Tan, Jianping; Lu, Ting; Pan, Likun; Xuan, Fuzhen

    2018-06-08

    Wearable strain sensors based on nanomaterial/elastomer composites have potential applications in flexible electronic skin, human motion detection, human-machine interfaces, etc. In this research, a type of high performance strain sensors has been developed using fragmentized carbon nanotube/polydimethylsiloxane (CNT/PDMS) composites. The CNT/PDMS composites were ground into fragments, and a liquid-induced densification method was used to fabricate the strain sensors. The strain sensors showed high sensitivity with gauge factors (GFs) larger than 200 and a broad strain detection range up to 80%, much higher than those strain sensors based on unfragmentized CNT/PDMS composites (GF sensors is ascribed to the sliding of individual fragmentized-CNT/PDMS-composite particles during mechanical deformation, which causes significant resistance change in the strain sensors. The strain sensors can differentiate mechanical stimuli and monitor various human body motions, such as bending of the fingers, human breathing, and blood pulsing.

  16. Cellulose nanofibril/reduced graphene oxide/carbon nanotube hybrid aerogels for highly flexible and all-solid-state supercapacitors

    Science.gov (United States)

    Qifeng Zheng; Zhiyong Cai; Zhenqiang Ma; Shaoqin Gong

    2015-01-01

    A novel type of highly flexible and all-solid-state supercapacitor that uses cellulose nanofibril (CNF)/reduced graphene oxide (RGO)/carbon nanotube (CNT) hybrid aerogels as electrodes and H2SO4 poly (vinyl alcohol) PVA gel as the electrolyte was developed and is reported here. These flexible solid-state supercapacitors...

  17. Dispersion and Reinforcement of Nanotubes in High Temperature Polymers for Ultrahigh Strength and Thermally Conductive Nanocomposites

    National Research Council Canada - National Science Library

    Yang, Arnold C

    2007-01-01

    Fundamental approaches for controlled dispersion of multiwalled carbon nanotubes in polymers and the molecular reinforcement in their nanocomposites were studied to design and fabricate well-dispersed...

  18. Highly selective solid-phase extraction of trace Pd(II) by murexide functionalized halloysite nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Li Ruijun; He Qun; Hu Zheng; Zhang Shengrui [Department of Chemistry, Lanzhou University, Lanzhou 730000 (China); Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province, Lanzhou 730000 (China); Zhang Lijun [Faculty of Science and Engineer, Curtin University, Perth, WA 6845 (Australia); Chang Xijun, E-mail: lirj2010@lzu.edu.cn [Department of Chemistry, Lanzhou University, Lanzhou 730000 (China); Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province, Lanzhou 730000 (China)

    2012-02-03

    Graphical abstract: Murexide functionalized halloysite nanotubes have been developed to separate and concentrate trace Pd(II) from aqueous samples. Parameters that affected the sorption and elution efficiency were studied in column mode, and the new adsorbent presented high selectivity and adsorption capacity for the solid phase extraction of trace Pd(II). Highlights: Black-Right-Pointing-Pointer Murexide modified halloysite nanotubes as adsorbent has been reported originally. Black-Right-Pointing-Pointer This adsorbent has a unique selectivity for Pd(II) at pH 1.0. Black-Right-Pointing-Pointer This adsorbent had high adsorption capacity for Pd(II). Black-Right-Pointing-Pointer The precision and accuracy of the method are satisfactory. - Abstract: The originality on the high efficiency of murexide modified halloysite nanotubes as a new adsorbent of solid phase extraction has been reported to preconcentrate and separate Pd(II) in solution samples. The new adsorbent was confirmed by Fourier transformed infrared spectra, X-ray diffraction, scanning electron microscope, transmission electron microscope and N{sub 2} adsorption-desorption isotherms. Effective preconcentration conditions of analyte were examined using column procedures prior to detection by inductively coupled plasma-optical emission spectrometry (ICP-OES). The effects of pH, the amount of adsorbent, the sample flow rate and volume, the elution condition and the interfering ions were optimized in detail. Under the optimized conditions, Pd(II) could be retained on the column at pH 1.0 and quantitatively eluted by 2.5 mL of 0.01 mol L{sup -1} HCl-3% thiourea solution at a flow rate of 2.0 mL min{sup -1}. The analysis time was 5 min. An enrichment factor of 120 was accomplished. Common interfering ions did not interfere in both separation and determination. The maximum adsorption capacity of the adsorbent at optimum conditions was found to be 42.86 mg g{sup -1} for Pd(II). The detection limit (3{sigma}) of

  19. Highly selective solid-phase extraction of trace Pd(II) by murexide functionalized halloysite nanotubes

    International Nuclear Information System (INIS)

    Li Ruijun; He Qun; Hu Zheng; Zhang Shengrui; Zhang Lijun; Chang Xijun

    2012-01-01

    Graphical abstract: Murexide functionalized halloysite nanotubes have been developed to separate and concentrate trace Pd(II) from aqueous samples. Parameters that affected the sorption and elution efficiency were studied in column mode, and the new adsorbent presented high selectivity and adsorption capacity for the solid phase extraction of trace Pd(II). Highlights: ► Murexide modified halloysite nanotubes as adsorbent has been reported originally. ► This adsorbent has a unique selectivity for Pd(II) at pH 1.0. ► This adsorbent had high adsorption capacity for Pd(II). ► The precision and accuracy of the method are satisfactory. - Abstract: The originality on the high efficiency of murexide modified halloysite nanotubes as a new adsorbent of solid phase extraction has been reported to preconcentrate and separate Pd(II) in solution samples. The new adsorbent was confirmed by Fourier transformed infrared spectra, X-ray diffraction, scanning electron microscope, transmission electron microscope and N 2 adsorption–desorption isotherms. Effective preconcentration conditions of analyte were examined using column procedures prior to detection by inductively coupled plasma-optical emission spectrometry (ICP-OES). The effects of pH, the amount of adsorbent, the sample flow rate and volume, the elution condition and the interfering ions were optimized in detail. Under the optimized conditions, Pd(II) could be retained on the column at pH 1.0 and quantitatively eluted by 2.5 mL of 0.01 mol L −1 HCl–3% thiourea solution at a flow rate of 2.0 mL min −1 . The analysis time was 5 min. An enrichment factor of 120 was accomplished. Common interfering ions did not interfere in both separation and determination. The maximum adsorption capacity of the adsorbent at optimum conditions was found to be 42.86 mg g −1 for Pd(II). The detection limit (3σ) of the method was 0.29 ng mL −1 , and the relative standard deviation (RSD) was 3.1% (n = 11). The method was

  20. Ultrafine Cobalt Sulfide Nanoparticles Encapsulated Hierarchical N-doped Carbon Nanotubes for High-performance Lithium Storage

    International Nuclear Information System (INIS)

    Li, Xiaoyan; Fu, Nianqing; Zou, Jizhao; Zeng, Xierong; Chen, Yuming; Zhou, Limin; Lu, Wei; Huang, Haitao

    2017-01-01

    Graphical abstract: Ultrafine cobalt sulfide nanoparticles encapsulated in hierarchical N-doped carbon nanotubes show exceptional lithium ion storage as anodes. - Abstract: Nanostructured cobalt sulfide based materials with rational design are attractive for high-performance lithium-ion batteries. In this work, we report a multistep method to synthesize ultrafine cobalt sulfide nanoparticles encapsulated in hierarchical N-doped carbon nanotubes (CoS x @HNCNTs). Co-based zeolitic imidazolate framework (ZIF-67) nanotubes are obtained from the reaction between electrospun polyacrylonitrile/cobalt acetate and 2-methylimidazole, followed by the dissolution of template. Next, a combined calcination and sulfidation process is employed to convert the ZIF-67 nanotubes to CoS x @HNCNTs. Benefited from the compositional and structural features, the as-prepared nanostructured hybrid materials deliver superior lithium storage properties with high capacity of 1200 mAh g −1 at 0.25 A g −1 . More importantly, a remarkable capacity of 1086 mAh g −1 can be maintained after 100 cycles at the current density of 0.5 A g −1 . Even at a high rate of 5 A g −1 , a reversible capacity of 592 mAh g −1 after 1600 cycles can still be achieved.

  1. Co/N–C nanotubes with increased coupling sites by space-confined pyrolysis for high electrocatalytic activity

    Directory of Open Access Journals (Sweden)

    Jun Yang

    2017-01-01

    Full Text Available Searching low cost and non-precious metal catalysts for high-performance oxygen reduction reaction is highly desired. Herein, Co nanoparticles embedded in nitrogen-doped carbon (Co/N–C nanotubes with internal void space are successfully synthesized by space-confined pyrolysis, which effectively improve the cobalt loading content and restrict the encapsulated particles down to nanometer. Different from the typical conformal carbon encapsulation, the resulting Co/N–C nanotubes possess more cobalt nanoparticles embedded in the nanotubes, which can provide more coupling sites and active sites in the oxygen reduction reaction (ORR. Moreover, the one-dimensional and porous structure provides a high surface area and a fast electron transfer pathway for the ORR. And the Co/N–C electrode presents excellent electrocatalytic ORR activity in terms of low onset potential (30 mV lower than that of Pt/C, small Tafel slop (45.5 mV dec−1 and good durability (88.5% retention after 10,000 s. Keywords: Co nanoparticles, Nitrogen-doped carbon nanotubes, Oxygen reduction reaction

  2. Titanate nanotube thin films with enhanced thermal stability and high-transparency prepared from additive-free sols

    Energy Technology Data Exchange (ETDEWEB)

    Koroesi, Laszlo, E-mail: korosi@enviroinvest.hu [Supramolecular and Nanostructured Materials Research Group of the Hungarian Academy of Sciences, University of Szeged, Aradi vertanuk tere 1, H-6720 Szeged (Hungary); Department of Biotechnology, Nanophage Therapy Center, Enviroinvest Corporation, Kertvaros utca 2, H-7632 Pecs (Hungary); Papp, Szilvia [Supramolecular and Nanostructured Materials Research Group of the Hungarian Academy of Sciences, University of Szeged, Aradi vertanuk tere 1, H-6720 Szeged (Hungary); Department of Biotechnology, Nanophage Therapy Center, Enviroinvest Corporation, Kertvaros utca 2, H-7632 Pecs (Hungary); Hornok, Viktoria [Supramolecular and Nanostructured Materials Research Group of the Hungarian Academy of Sciences, University of Szeged, Aradi vertanuk tere 1, H-6720 Szeged (Hungary); Oszko, Albert [Department of Physical Chemistry and Materials Science, University of Szeged, Aradi vertanuk tere 1, H-6720 Szeged (Hungary); Petrik, Peter; Patko, Daniel; Horvath, Robert [Institute for Technical Physics and Materials Science MFA, Research Center for Natural Sciences, Konkoly-Thege ut 29-33, H-1121 Budapest (Hungary); Dekany, Imre [Supramolecular and Nanostructured Materials Research Group of the Hungarian Academy of Sciences, University of Szeged, Aradi vertanuk tere 1, H-6720 Szeged (Hungary)

    2012-08-15

    Titanate nanotubes were synthesized from TiO{sub 2} in alkaline medium by a conventional hydrothermal method (150 Degree-Sign C, 4.7 bar). To obtain hydrogen titanates, the as-prepared sodium titanates were treated with either HCl or H{sub 3}PO{sub 4} aqueous solutions. A simple synthesis procedure was devised for stable titanate nanotube sols without using any additives. These highly stable ethanolic sols can readily be used to prepare transparent titanate nanotube thin films of high quality. The resulting samples were studied by X-ray diffraction, N{sub 2}-sorption measurements, Raman spectroscopy, transmission and scanning electron microscopy, X-ray photoelectron spectroscopy and spectroscopic ellipsometry. The comparative results of using two kinds of acids shed light on the superior thermal stability of the H{sub 3}PO{sub 4}-treated titanate nanotubes (P-TNTs). X-ray photoelectron spectroscopy revealed that P-TNTs contains P in the near-surface region and the thermal stability was enhanced even at a low ({approx}0.5 at%) concentration of P. After calcination at 500 Degree-Sign C, the specific surface areas of the HCl- and H{sub 3}PO{sub 4}-treated samples were 153 and 244 m{sup 2} g{sup -1}, respectively. The effects of H{sub 3}PO{sub 4} treatment on the structure, morphology and porosity of titanate nanotubes are discussed. - Graphical Abstract: TEM picture (left) shows P-TNTs with diameters about 5-6 nm. Inset shows a stable titanate nanotube sol illuminated by a 532 nm laser beam. Due to the presence of the nanoparticles the way of the light is visible in the sol. Cross sectional SEM picture (right) as well as ellipsometry revealed the formation of optical quality P-TNT films with thicknesses below 50 nm. Highlights: Black-Right-Pointing-Pointer H{sub 3}PO{sub 4} treatment led to TNTs with high surface area even after calcination at 500 Degree-Sign C. Black-Right-Pointing-Pointer H{sub 3}PO{sub 4}-treated TNTs preserved their nanotube morphology up to 500

  3. A Photodetector Based on p-Si/n-ZnO Nanotube Heterojunctions with High Ultraviolet Responsivity

    KAUST Repository

    Flemban, Tahani H.

    2017-09-19

    Enhanced ultraviolet (UV) photodetectors (PDs) with high responsivity comparable to that of visible and infrared photodetectors are needed for commercial applications. n-Type ZnO nanotubes (NTs) with high-quality optical, structural, and electrical properties on a p-type Si(100) substrate are successfully fabricated by pulsed laser deposition (PLD) to produce a UV PD with high responsivity, for the first time. We measure the current–voltage characteristics of the device under dark and illuminated conditions and demonstrated the high stability and responsivity (that reaches ∼101.2 A W–1) of the fabricated UV PD. Time-resolved spectroscopy is employed to identify exciton confinement, indicating that the high PD performance is due to optical confinement, the high surface-to-volume ratio, the high structural quality of the NTs, and the high photoinduced carrier density. The superior detectivity and responsivity of our NT-based PD clearly demonstrate that fabrication of high-performance UV detection devices for commercial applications is possible.

  4. High-performance photoresponse from single-walled carbon nanotube-zinc oxide heterojunctions

    International Nuclear Information System (INIS)

    Chang, Jingbo; Najeeb, Choolakadavil Khalid; Lee, Jae-Hyeok; Lee, Minsu; Kim, Jae-Ho

    2011-01-01

    Photoactive materials consisting of single-walled carbon nanotube (SWNT)-zinc oxide (ZnO) heterojunctions targeted for optoelectronic applications are investigated in terms of photoresponse and photovoltaic effects. The devices based on SWNT-ZnO heterojunction films are fabricated by two step processes: first, a well aligned SWNT monolayer is deposited on an oxide substrate by the Langmuir-Blodgett (LB) technique; then a ZnO film prepared by filtration of ZnO nanowire solution is transferred onto the SWNT film to form SWNT-ZnO junctions. The SWNT-ZnO heterojunction demonstrates faster photoresponse time (2.75 s) up to 18 times and photovoltaic efficiency (1.33 nA) up to 4 times higher than that of only a ZnO device. Furthermore, the mechanisms of UV sensitivity enhancement and photovoltaic effects are explained according to the high electron mobility in the SWNT-ZnO heterojunctions.

  5. Low temperature growth of ultra-high mass density carbon nanotube forests on conductive supports

    International Nuclear Information System (INIS)

    Sugime, Hisashi; Esconjauregui, Santiago; Yang, Junwei; D'Arsié, Lorenzo; Robertson, John; Oliver, Rachel A.; Bhardwaj, Sunil; Cepek, Cinzia

    2013-01-01

    We grow ultra-high mass density carbon nanotube forests at 450 °C on Ti-coated Cu supports using Co-Mo co-catalyst. X-ray photoelectron spectroscopy shows Mo strongly interacts with Ti and Co, suppressing both aggregation and lifting off of Co particles and, thus, promoting the root growth mechanism. The forests average a height of 0.38 μm and a mass density of 1.6 g cm −3 . This mass density is the highest reported so far, even at higher temperatures or on insulators. The forests and Cu supports show ohmic conductivity (lowest resistance ∼22 kΩ), suggesting Co-Mo is useful for applications requiring forest growth on conductors

  6. Carbon nanotubes as nanotexturing agents for high power supercapacitors based on seaweed carbons.

    Science.gov (United States)

    Raymundo-Piñero, Encarnación; Cadek, Martin; Wachtler, Mario; Béguin, François

    2011-07-18

    The advantages provided by multiwalled carbon nanotubes (CNTs) as backbones for composite supercapacitor electrodes are discussed. This paper particularly highlights the electrochemical properties of carbon composites obtained by pyrolysis of seaweed/CNTs blends. Due to the nanotexturing effect of CNTs, supercapacitors fabricated with electrodes from these composites exhibit enhanced electrochemical performances compared with CNT-free carbons. The cell resistance is dramatically reduced by the excellent conductivity of CNTs and by the good propagation of ions favored by the presence of opened mesopores. As a consequence, the specific power of supercapacitors based on these nanocomposites is very high. Another advantage related to the presence of CNTs is a better life cycle of the systems. The composite electrodes are resilient during the charge/discharge of capacitors; these are able to perfectly accommodate the dimensional changes appearing in the active material without mechanical damages. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. High Methanol Oxidation Activity of Well-Dispersed Pt Nanoparticles on Carbon Nanotubes Using Nitrogen Doping

    Directory of Open Access Journals (Sweden)

    Fang Wei-Chuan

    2009-01-01

    Full Text Available Abstract Pt nanoparticles (NPs with the average size of 3.14 nm well dispersed on N-doped carbon nanotubes (CNTs without any pretreatment have been demonstrated. Structural properties show the characteristic N bonding within CNTs, which provide the good support for uniform distribution of Pt NPs. In electrochemical characteristics, N-doped CNTs covered with Pt NPs show superior current density due to the fact that the so-called N incorporation could give rise to the formation of preferential sites within CNTs accompanied by the low interfacial energy for immobilizing Pt NPs. Therefore, the substantially enhanced methanol oxidation activity performed by N-incorporation technique is highly promising in energy-generation applications.

  8. Short time synthesis of high quality carbon nanotubes with high rates by CVD of methane on continuously emerged iron nanoparticles

    International Nuclear Information System (INIS)

    Bahrami, Behnam; Khodadadi, Abasali; Mortazavi, Yadollah; Esmaieli, Mohamad

    2011-01-01

    We report the variation of yield and quality of carbon nanotubes (CNTs) grown by chemical vapor deposition (CVD) of methane on iron oxide-MgO at 900-1000 deg. C for 1-60 min. The catalyst was prepared by impregnation of MgO powder with iron nitrate, dried, and calcined at 300 deg. C. As calcined and unreduced catalyst in quartz reactor was brought to the synthesis temperature in helium flow in a few minutes, and then the flow was switched to methane. The iron oxide was reduced to iron nanoparticles in methane, while the CNTs were growing. TEM micrographs, in accordance with Raman RBM peaks, indicate the formation of mostly single wall carbon nanotubes of about 1.0 nm size. High quality CNTs with I G /I D Raman peak ratio of 14.5 are formed in the first minute of CNTs synthesis with the highest rate. Both the rate and quality of CNTs degrades with increasing CNTs synthesis time. Also CNTs quality sharply declines with temperature in the range of 900-1000 deg. C, while the CNTs yield passes through a maximum at 950 deg. C. About the same CNTs lengths are formed for the whole range of the synthesis times. A model of continuous emergence of iron nanoparticle seeds for CNTs synthesis may explain the data. The data can also provide information for continuous production of CNTs in a fluidized bed reactor.

  9. Short time synthesis of high quality carbon nanotubes with high rates by CVD of methane on continuously emerged iron nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Bahrami, Behnam, E-mail: bahrami@email.sc.edu [Catalysis and Nanostructured Materials Research Laboratory, School of Chemical Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Nanoelectronics Centre of Excellence, University of Tehran, Tehran (Iran, Islamic Republic of); Khodadadi, Abasali [Catalysis and Nanostructured Materials Research Laboratory, School of Chemical Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Mortazavi, Yadollah, E-mail: mortazav@ut.ac.ir [Nanoelectronics Centre of Excellence, University of Tehran, Tehran (Iran, Islamic Republic of); Esmaieli, Mohamad [Nanoelectronics Centre of Excellence, University of Tehran, Tehran (Iran, Islamic Republic of)

    2011-09-15

    We report the variation of yield and quality of carbon nanotubes (CNTs) grown by chemical vapor deposition (CVD) of methane on iron oxide-MgO at 900-1000 deg. C for 1-60 min. The catalyst was prepared by impregnation of MgO powder with iron nitrate, dried, and calcined at 300 deg. C. As calcined and unreduced catalyst in quartz reactor was brought to the synthesis temperature in helium flow in a few minutes, and then the flow was switched to methane. The iron oxide was reduced to iron nanoparticles in methane, while the CNTs were growing. TEM micrographs, in accordance with Raman RBM peaks, indicate the formation of mostly single wall carbon nanotubes of about 1.0 nm size. High quality CNTs with I{sub G}/I{sub D} Raman peak ratio of 14.5 are formed in the first minute of CNTs synthesis with the highest rate. Both the rate and quality of CNTs degrades with increasing CNTs synthesis time. Also CNTs quality sharply declines with temperature in the range of 900-1000 deg. C, while the CNTs yield passes through a maximum at 950 deg. C. About the same CNTs lengths are formed for the whole range of the synthesis times. A model of continuous emergence of iron nanoparticle seeds for CNTs synthesis may explain the data. The data can also provide information for continuous production of CNTs in a fluidized bed reactor.

  10. Carbon Nanotube Web with Carboxylated Polythiophene "Assist" for High-Performance Battery Electrodes.

    Science.gov (United States)

    Kwon, Yo Han; Park, Jung Jin; Housel, Lisa M; Minnici, Krysten; Zhang, Guoyan; Lee, Sujin R; Lee, Seung Woo; Chen, Zhongming; Noda, Suguru; Takeuchi, Esther S; Takeuchi, Kenneth J; Marschilok, Amy C; Reichmanis, Elsa

    2018-04-24

    A carbon nanotube (CNT) web electrode comprising magnetite spheres and few-walled carbon nanotubes (FWNTs) linked by the carboxylated conjugated polymer, poly[3-(potassium-4-butanoate) thiophene] (PPBT), was designed to demonstrate benefits derived from the rational consideration of electron/ion transport coupled with the surface chemistry of the electrode materials components. To maximize transport properties, the approach introduces monodispersed spherical Fe 3 O 4 (sFe 3 O 4 ) for uniform Li + diffusion and a FWNT web electrode frame that affords characteristics of long-ranged electronic pathways and porous networks. The sFe 3 O 4 particles were used as a model high-capacity energy active material, owing to their well-defined chemistry with surface hydroxyl (-OH) functionalities that provide for facile detection of molecular interactions. PPBT, having a π-conjugated backbone and alkyl side chains substituted with carboxylate moieties, interacted with the FWNT π-electron-rich and hydroxylated sFe 3 O 4 surfaces, which enabled the formation of effective electrical bridges between the respective components, contributing to efficient electron transport and electrode stability. To further induce interactions between PPBT and the metal hydroxide surface, polyethylene glycol was coated onto the sFe 3 O 4 particles, allowing for facile materials dispersion and connectivity. Additionally, the introduction of carbon particles into the web electrode minimized sFe 3 O 4 aggregation and afforded more porous FWNT networks. As a consequence, the design of composite electrodes with rigorous consideration of specific molecular interactions induced by the surface chemistries favorably influenced electrochemical kinetics and electrode resistance, which afforded high-performance electrodes for battery applications.

  11. Facile synthesis of highly aligned multiwalled carbon nanotubes from polymer precursors.

    Energy Technology Data Exchange (ETDEWEB)

    Han, C. Y.; Xiao, Z.-L.; Wang, H. H.; Lin, X.-M.; Trasobares, S.; Cook, R. E.; Richard J. Daley Coll.; Northern Illinois Univ.; Univ. de Cadiz

    2009-01-01

    We report a facile one-step approach which involves no flammable gas, no catalyst, and no in situ polymerization for the preparation of well-aligned carbon nanotube array. A polymer precursor is placed on top of an anodized aluminum oxide (AAO) membrane containing regular nanopore arrays, and slow heating under Ar flow allows the molten polymer to wet the template through adhesive force. The polymer spread into the nanopores of the template to form polymer nanotubes. Upon carbonization the resulting multi-walled carbon nanotubes duplicate the nanopores morphology precisely. The process is demonstrated for 230, 50, and 20 nm pore membranes. The synthesized carbon nanotubes are characterized with scanning/transmission electron microscopies, Raman spectroscopy, and resistive measurements. Convenient functionalization of the nanotubes with this method is demonstrated through premixing CoPt nanoparticles in the polymer precursors.

  12. Facile Synthesis of Highly Aligned Multiwalled Carbon Nanotubes from Polymer Precursors

    Directory of Open Access Journals (Sweden)

    Catherine Y. Han

    2009-01-01

    Full Text Available We report a facile one-step approach which involves no flammable gas, no catalyst, and no in situ polymerization for the preparation of well-aligned carbon nanotube array. A polymer precursor is placed on top of an anodized aluminum oxide (AAO membrane containing regular nanopore arrays, and slow heating under Ar flow allows the molten polymer to wet the template through adhesive force. The polymer spread into the nanopores of the template to form polymer nanotubes. Upon carbonization the resulting multi-walled carbon nanotubes duplicate the nanopores morphology precisely. The process is demonstrated for 230, 50, and 20 nm pore membranes. The synthesized carbon nanotubes are characterized with scanning/transmission electron microscopies, Raman spectroscopy, and resistive measurements. Convenient functionalization of the nanotubes with this method is demonstrated through premixing CoPt nanoparticles in the polymer precursors.

  13. High-efficiency perovskite solar cells based on anatase TiO{sub 2} nanotube arrays

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Yan, E-mail: huangyan@ecust.edu.cn [School of Chemistry and Molecular Engineering, East China University of Science & Technology, Shanghai 200237 (China); Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Wu, Jiamin; Gao, Di [Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States)

    2016-01-01

    Perovskite solar cells (PSCs) based on one-dimensional anatase TiO{sub 2} nanotube arrays were prepared by using a two-step deposition method to fill the arrays of TiO{sub 2} nanotubes in different lengths with perovskite. The photovoltaic performance of PSCs was found to be significantly dependent on the length of the TiO{sub 2} nanotubes, and the power conversion efficiency decreased as the length of the TiO{sub 2} nanotubes increased from ~ 0.40 μm to ~ 0.65 and then to ~ 0.93 μm. The PSC fabricated with ~ 0.40 μm-long anatase TiO{sub 2} nanotube arrays yielded a power conversion efficiency of 11.3% and a fill factor of 0.68 under illumination of 100 mW/cm{sup 2} AM 1.5G simulated sunlight, which is significantly higher than previously reported solar cells based on 1-D TiO{sub 2} nanostructures. Incident photon-to-current efficiency and electrochemical impedance spectroscopy measurements indicated that longer TiO{sub 2} nanotubes led to higher recombination losses of charge carriers, possibly due to poor filling of the nanotube arrays with perovskite. - Highlights: • 1D anatase TiO{sub 2} nanotubes were used to fabricate perovskite solar cells. • The best efficiency of 11.3% was achieved with ~ 0.40 μm-long TiO{sub 2} nanotubes. • The efficiency of the devices decreased with increasing TiO{sub 2} nanotube lengths.

  14. Fabricating and strengthening the carbon nanotube/copper composite fibers with high strength and high electrical conductivity

    Science.gov (United States)

    Han, Baoshuai; Guo, Enyu; Xue, Xiang; Zhao, Zhiyong; Li, Tiejun; Xu, Yanjin; Luo, Liangshun; Hou, Hongliang

    2018-05-01

    Combining the excellent properties of carbon nanotube (CNT) and copper, CNT/Cu composite fibers were fabricated by physical vapor deposition (PVD) and rolling treatment. Dense and continuous copper film (∼2 μm) was coated on the surface of the CNT fibers by PVD, and rolling treatment was adopt to strengthen the CNT/Cu composite fibers. After the rolling treatment, the defects between the Cu grains and the CNT bundles were eliminated, and the structure of both the copper film and the core CNT fibers were optimized. The rolled CNT/Cu composite fibers possess high tensile effective strength (1.01 ± 0.13 GPa) and high electrical conductivity ((2.6 ± 0.3) × 107 S/m), and thus, this material may become a promising wire material.

  15. Fracture toughness and failure mechanism of high performance concrete incorporating carbon nanotubes

    Directory of Open Access Journals (Sweden)

    A. Khitab

    2017-10-01

    Full Text Available Cement and concrete composites are inherently brittle and exhibit very less tensile/flexural strength capacity as compared to their compressive strength. Use of thoroughly dispersed carbon nanotubes in the concrete matrix is one of the possible solution for enhancing mechanical properties in tension/flexure. In the present research work, small fractions of multiwall carbon nanotube (MWCNTs i.e. 0.05 and 0.10 wt% of cement have been integrated into the cement concrete to study their effect on the mechanical properties of the resultant concrete mixtures. The enhanced performance of the whole mix lies on a single point that MWCNTs must be thoroughly disperse in the mixture. Hence, special arrangement through usage of high energy sonication along with amended acrylic based polymer (performing as a surfactant was made to have a uniform dispersion of MWCNTs in the concrete mix. The testing of concrete samples includes i.e., flexure, splitting tensile and compressive strengths after 3, 7, 28 and 56 days of curing. After having comparison with the control mix cured for 28 days, it was observed that the addition of 0.05 wt% MWCNTs increased the splitting tensile strength by 20.58%, flexural strength by 26.29% and compressive strength by 15.60%. Through above results, which verify the increase in concrete mix strength after adding MWCNTs, these MWCNTs may be incorporated in the treatment of Nano/micro cracks completed through process of connecting, branching and pinning. Similarly, as proved in threepoint bending tests, MWCNTs also enhances the breaking strains as well as the fracture energy of the concrete mixes, besides, imparting increase to the strength. The investigations have shown that incorporating lesser amounts of MWCNTs i.e., 0.05 and 0.10 wt% of cement to the concrete mixes after insuring there complete dispersion, unusually improve their properties like mechanical strengths and fracture behavior

  16. High-yield growth of vertically aligned carbon nanotubes on a continuously moving substrate

    International Nuclear Information System (INIS)

    Guzman de Villoria, R; Hart, A J; Steiner, S A III; Wardle, B L; Figueredo, S L; Slocum, A H

    2009-01-01

    Vertically aligned carbon nanotube (CNT) arrays are grown on a moving substrate, demonstrating continuous growth of nanoscale materials with long-range order. A cold-wall chamber with an oscillating moving platform is used to locally heat a silicon growth substrate coated with an Fe/Al 2 O 3 catalyst film for CNT growth via chemical vapor deposition. The reactant gases are introduced over the substrate through a directed nozzle to attain high-yield CNT growth. Aligned multi-wall carbon nanotube arrays (or 'forests') with heights of ∼1 mm are achieved at substrate speeds up to 2.4 mm s -1 . Arrays grown on moving substrates at different velocities are studied in order to identify potential physical limitations of repeatable and fast growth on a continuous basis. No significant differences are noted between static and moving growth as characterized by scanning electron microscopy and Raman spectroscopy, although overall growth height is marginally reduced at the highest substrate velocity. CNT arrays produced on moving substrates are also found to be comparable to those produced through well-characterized batch processes consistent with a base-growth mechanism. Growth parameters required for the moving furnace are found to differ only slightly from those used in a comparable batch process; thermal uniformity appears to be the critical parameter for achieving large-area uniform array growth. If the continuous-growth technology is combined with a reaction zone isolation scheme common in other types of processing (e.g., in the manufacture of carbon fibers), large-scale dense and aligned CNT arrays may be efficiently grown and harvested for numerous applications including providing interlayers for advanced composite reinforcement and improved electrical and thermal transport.

  17. High-yield growth of vertically aligned carbon nanotubes on a continuously moving substrate.

    Science.gov (United States)

    Guzmán de Villoria, R; Figueredo, S L; Hart, A J; Steiner, S A; Slocum, A H; Wardle, B L

    2009-10-07

    Vertically aligned carbon nanotube (CNT) arrays are grown on a moving substrate, demonstrating continuous growth of nanoscale materials with long-range order. A cold-wall chamber with an oscillating moving platform is used to locally heat a silicon growth substrate coated with an Fe/Al2O3 catalyst film for CNT growth via chemical vapor deposition. The reactant gases are introduced over the substrate through a directed nozzle to attain high-yield CNT growth. Aligned multi-wall carbon nanotube arrays (or 'forests') with heights of approximately 1 mm are achieved at substrate speeds up to 2.4 mm s(-1). Arrays grown on moving substrates at different velocities are studied in order to identify potential physical limitations of repeatable and fast growth on a continuous basis. No significant differences are noted between static and moving growth as characterized by scanning electron microscopy and Raman spectroscopy, although overall growth height is marginally reduced at the highest substrate velocity. CNT arrays produced on moving substrates are also found to be comparable to those produced through well-characterized batch processes consistent with a base-growth mechanism. Growth parameters required for the moving furnace are found to differ only slightly from those used in a comparable batch process; thermal uniformity appears to be the critical parameter for achieving large-area uniform array growth. If the continuous-growth technology is combined with a reaction zone isolation scheme common in other types of processing (e.g., in the manufacture of carbon fibers), large-scale dense and aligned CNT arrays may be efficiently grown and harvested for numerous applications including providing interlayers for advanced composite reinforcement and improved electrical and thermal transport.

  18. Determination of puerarin in rat plasma using PEGylated magnetic carbon nanotubes by high performance liquid chromatography.

    Science.gov (United States)

    Yu, Panfeng; Wang, Qi; Ma, Hongwei; Wu, Ji; Shen, Shun

    2014-05-15

    This paper described a novel application of PEGylated magnetic carbon nanotubes as solid-phase extraction nanosorbents for the determination of puerarin in rat plasma by high performance liquid chromatography (HPLC). A solvothermal method was employed for the synthesis of monodisperse magnetites anchored onto multi-walled carbon nanotubes (MWCNTs@Fe3O4). In order to enhance the water solubility of MWCNTs@Fe3O4 that ensured sufficient contact between nanosorbents and analytes in the sampling procedure, the obtained nanomaterials were further noncovalently functionalized using a phospholipids-polyethylene glycol (DSPE-PEG). The PEGylated MWCNTs@Fe3O4 nanomaterials had an extremely large surface area and exhibit a strong interaction capability for puerarin with π-π stacking interactions. The captured puerarin/nanosorbents were easily isolated from the plasma by placing a magnet, and desorbed by acetonitrile. The experimental variables affecting the extraction efficiency were investigated. The calibration curve of puerarin was linear from 0.01 to 20 μg/ml, and the limit of detection was 0.005 μg/ml. The precisions ranged from 2.7% to 3.5% for within-day measurement, and for between-day variation was in the range of 3.1-5.9%. The method recoveries were acquired from 95.2% to 98.0%. Moreover, the analytical performance obtained by PEGylated magnetic MWCNTs was also compared with that of magnetic MWCNTs. All results showed that our proposed method was an excellent alternative for the analysis of puerarin in rat plasma. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Room temperature chemical synthesis of highly oriented PbSe nanotubes based on negative free energy of formation

    Energy Technology Data Exchange (ETDEWEB)

    Sankapal, B.R., E-mail: brsankapal@rediffmail.com [Thin Film and Nano Science Laboratory, Department of Physics, School of Physical Sciences, North Maharashtra University, Jalgaon 425 001 (MS) (India); Ladhe, R.D.; Salunkhe, D.B.; Baviskar, P.K. [Thin Film and Nano Science Laboratory, Department of Physics, School of Physical Sciences, North Maharashtra University, Jalgaon 425 001 (MS) (India); Gupta, V.; Chand, S. [Organic and Hybrid Solar Cell, Physics of Energy Harvesting Division, Dr. K.S. Krishnan Marg, National Physical Laboratory, New Delhi 110012 (India)

    2011-10-13

    Highlights: > Simple, inexpensive and room temperature chemical synthesis route. > Highly oriented PbSe nanotubes from Cd(OH){sub 2} nanowires through lead hydroxination. > The process was template free without the use of any capping agent. > Reaction kinetics was accomplished due to more negative free energy of formation. > The ion exchange mechanism due to difference in the solubility products. - Abstract: The sacrificial template free chemical synthesis of PbSe nanotubes at room temperature has been performed by lead hydroxination from cadmium hydroxide nanowires. This process was based on the ion exchange reaction to replace Cd{sup 2+} with Pb{sup 2+} ions from hydroxyl group followed by replacement of hydroxyl group with selenium ions. The reaction kinetics was accomplished due to more negative free energy of formation and thus the difference in the solubility products. The formed nanotubes were inclusive of Pb and Se with proper inter-chemical bonds with preferred orientations having diameter in tens of nanometer. These nanotubes can have future applications in electronic, optoelectronics and photovoltaic's as well.

  20. Investigation of anodic TiO2 nanotube composition with high spatial resolution AES and ToF SIMS

    Science.gov (United States)

    Dronov, Alexey; Gavrilin, Ilya; Kirilenko, Elena; Dronova, Daria; Gavrilov, Sergey

    2018-03-01

    High resolution Scanning Auger Electron Spectroscopy (AES) and Time-of-Flight Secondary Ion Mass-Spectrometry (ToF SIMS) were used to investigate structure and elemental composition variation of both across an array of TiO2 nanotubes (NTs) and single tube of an array. The TiO2 NT array was grown by anodic oxidation of Ti foil in fluorine-containing ethylene glycol electrolyte. It was found that the studied anodic TiO2 nanotubes have a layered structure with rather sharp interfaces. The differences in AES depth profiling results of a single tube with the focused primary electron beam (point analysis) and over an area of 75 μm in diameter of a nanotube array with the defocused primary electron beam are discussed. Depth profiling by ToF SIMS was carried out over approximately the same size of a nanotube array to determine possible ionic fragments in the structure. The analysis results show that the combination of both mentioned methods is useful for a detailed analysis of nanostructures with complex morphology and multi-layered nature.

  1. Room temperature chemical synthesis of highly oriented PbSe nanotubes based on negative free energy of formation

    International Nuclear Information System (INIS)

    Sankapal, B.R.; Ladhe, R.D.; Salunkhe, D.B.; Baviskar, P.K.; Gupta, V.; Chand, S.

    2011-01-01

    Highlights: → Simple, inexpensive and room temperature chemical synthesis route. → Highly oriented PbSe nanotubes from Cd(OH) 2 nanowires through lead hydroxination. → The process was template free without the use of any capping agent. → Reaction kinetics was accomplished due to more negative free energy of formation. → The ion exchange mechanism due to difference in the solubility products. - Abstract: The sacrificial template free chemical synthesis of PbSe nanotubes at room temperature has been performed by lead hydroxination from cadmium hydroxide nanowires. This process was based on the ion exchange reaction to replace Cd 2+ with Pb 2+ ions from hydroxyl group followed by replacement of hydroxyl group with selenium ions. The reaction kinetics was accomplished due to more negative free energy of formation and thus the difference in the solubility products. The formed nanotubes were inclusive of Pb and Se with proper inter-chemical bonds with preferred orientations having diameter in tens of nanometer. These nanotubes can have future applications in electronic, optoelectronics and photovoltaic's as well.

  2. Nano-engineering of three-dimensional core/shell nanotube arrays for high performance supercapacitors

    Science.gov (United States)

    Grote, Fabian; Wen, Liaoyong; Lei, Yong

    2014-06-01

    Large-scale arrays of core/shell nanostructures are highly desirable to enhance the performance of supercapacitors. Here we demonstrate an innovative template-based fabrication technique with high structural controllability, which is capable of synthesizing well-ordered three-dimensional arrays of SnO2/MnO2 core/shell nanotubes for electrochemical energy storage in supercapacitor applications. The SnO2 core is fabricated by atomic layer deposition and provides a highly electrical conductive matrix. Subsequently a thin MnO2 shell is coated by electrochemical deposition onto the SnO2 core, which guarantees a short ion diffusion length within the shell. The core/shell structure shows an excellent electrochemical performance with a high specific capacitance of 910 F g-1 at 1 A g-1 and a good rate capability of remaining 217 F g-1 at 50 A g-1. These results shall pave the way to realize aqueous based asymmetric supercapacitors with high specific power and high specific energy.

  3. A vacuum sealed high emission current and transmission efficiency carbon nanotube triode

    Energy Technology Data Exchange (ETDEWEB)

    Di, Yunsong [School of Electronic Science & Engineering, Southeast University, Nanjing 210096 (China); Jiangsu Key Laboratory of Optoelectronic Technology, Nanjing Normal University, Nanjing 210023 (China); Wang, Qilong; Zhang, Xiaobing, E-mail: bell@seu.edu.cn; Lei, Wei; Du, Xiaofei; Yu, Cairu [School of Electronic Science & Engineering, Southeast University, Nanjing 210096 (China)

    2016-04-15

    A vacuum sealed carbon nanotubes (CNTs) triode with a concave and spoke-shaped Mo grid is presented. Due to the high aperture ratio of the grid, the emission current could be modulated at a relatively high electric field. Totally 75 mA emission current has been obtained from the CNTs cathode with the average applied field by the grid shifting from 8 to 13 V/μm. Whilst with the electron transmission efficiency of the grid over 56%, a remarkable high modulated current electron beam over 42 mA has been collected by the anode. Also contributed by the high aperture ration of the grid, desorbed gas molecules could flow away from the emission area rapidly when the triode has been operated at a relative high emission current, and finally collected by a vacion pump. The working pressure has been maintained at ∼1 × 10{sup −7} Torr, seldom spark phenomena occurred. Nearly perfect I-V curve and corresponding Fowler-Nordheim (FN) plot confirmed the accuracy of the measured data, and the emission current was long term stable and reproducible. Thusly, this kind of triode would be used as a high-power electron source.

  4. High-performance lithium storage of Co3O4 achieved by constructing porous nanotube structure

    International Nuclear Information System (INIS)

    Cui, Zhentao; Wang, Shuguang; Zhang, Yihe; Cao, Minhua

    2015-01-01

    Graphical abstract: The porous Co 3 O 4 nanotubes (P-Co 3 O 4 -NTs) are prepared by coaxial electrospinning method followed by a fine annealing treatment. The resultant P-Co 3 O 4 -NTs exhibit excellent lithium storage performance in terms of specific capacity, rate capability, and cycling stability when used as an anode material for rechargeable lithium ion batteries (LIBs). - Abstract: Co 3 O 4 has been investigated intensively for its high specific capacity which makes it a promising candidate anode for high-performance lithium ion batteries (LIBs). However, rational design of Co 3 O 4 electrode that is beneficial for its electrochemical performance is still a great challenge. Herein, we designed and fabricated porous Co 3 O 4 nanotubes (P-Co 3 O 4 -NTs) by coaxial electrospinning method followed by a fine annealing treatment, which display one dimensional tubular structure with porous wall and hollow interior. The uniqueness of this strategy is that the morphologies of the P-Co 3 O 4 -NTs could be tuned by adjusting the mass ratio of reactants. The resultant P-Co 3 O 4 -NTs exhibit excellent lithium storage performance in terms of specific capacity, rate capability, and cycling stability, when used as an anode material for rechargeable LIBs. This unique structure endows a high reversible specific capacity of 1826.2 mA g −1 at a current density of 0.3 A g −1 after 100 cycles. Even at high current densities of 2 and 5 A g −1 , the P-Co 3 O 4 -NTs electrode still could deliver remarkable discharge capacities of 1506.2 and 1145.1 mAh g −1 , respectively. The excellent electrochemical performance can be attributed to the unique tubular and porous structure of P-Co 3 O 4 -NTs, which not only can accommodate the large volume change but also can provide an excellent ion diffusion and electronic conduction pathway. Therefore, the P-Co 3 O 4 -NTs have the potential for use as a high performance anode material in LIBs.

  5. Polymer-Assisted Direct Deposition of Uniform Carbon Nanotube Bundle Networks for High Performance Transparent Electrodes

    KAUST Repository

    Hellstrom, Sondra L.; Lee, Hang Woo; Bao, Zhenan

    2009-01-01

    Flexible transparent electrodes are crucial for touch screen, flat panel display, and solar cell technologies. While carbon nanotube network electrodes show promise, characteristically poor dispersion properties have limited their practicality. We report that addition of small amounts of conjugated polymer to nanotube dispersions enables straightforward fabrication of uniform network electrodes by spin-coating and simultaneous tuning of parameters such as bundle size and density. After treatment in thionyl chloride, electrodes have sheet resistances competitive with other reported carbon nanotube based transparent electrodes to date. © 2009 American Chemical Society.

  6. Polymer-Assisted Direct Deposition of Uniform Carbon Nanotube Bundle Networks for High Performance Transparent Electrodes

    KAUST Repository

    Hellstrom, Sondra L.

    2009-06-23

    Flexible transparent electrodes are crucial for touch screen, flat panel display, and solar cell technologies. While carbon nanotube network electrodes show promise, characteristically poor dispersion properties have limited their practicality. We report that addition of small amounts of conjugated polymer to nanotube dispersions enables straightforward fabrication of uniform network electrodes by spin-coating and simultaneous tuning of parameters such as bundle size and density. After treatment in thionyl chloride, electrodes have sheet resistances competitive with other reported carbon nanotube based transparent electrodes to date. © 2009 American Chemical Society.

  7. On the high charge-carrier mobility in polyaniline molecular channels in nanogaps between carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Emelianov, A. V., E-mail: emmsowton@gmail.com; Romashkin, A. V.; Tsarik, K. A. [National Research University of Electronic Technology (MIET) (Russian Federation); Nasibulin, A. G. [Skolkovo Institute of Science and Technology (Russian Federation); Nevolin, V. K.; Bobrinetskiy, I. I. [National Research University of Electronic Technology (MIET) (Russian Federation)

    2017-04-15

    This study is devoted to the fabrication of molecular semiconductor channels based on polymer molecules with nanoscale electrodes made of single-walled carbon nanotubes. A reproducible technology for forming nanoscale gaps in carbon nanotubes using a focused Ga{sup +} ion beam is proposed. Polyaniline molecules are deposited into nanogaps up to 30 nm wide between nanotubes by electrophoresis from N-methyl-2-pyrrolidone solution. As a result, molecular organic transistors are fabricated, in which the field effect is studied and the molecular-channel mobility is determined as 0.1 cm{sup 2}/(V s) at an on/off current ratio of 5 × 10{sup 2}.

  8. Ternary CNTs@TiO₂/CoO Nanotube Composites: Improved Anode Materials for High Performance Lithium Ion Batteries.

    Science.gov (United States)

    Madian, Mahmoud; Ummethala, Raghunandan; Naga, Ahmed Osama Abo El; Ismail, Nahla; Rümmeli, Mark Hermann; Eychmüller, Alexander; Giebeler, Lars

    2017-06-20

    TiO₂ nanotubes (NTs) synthesized by electrochemical anodization are discussed as very promising anodes for lithium ion batteries, owing to their high structural stability, high surface area, safety, and low production cost. However, their poor electronic conductivity and low Li⁺ ion diffusivity are the main drawbacks that prevent them from achieving high electrochemical performance. Herein, we report the fabrication of a novel ternary carbon nanotubes (CNTs)@TiO₂/CoO nanotubes composite by a two-step synthesis method. The preparation includes an initial anodic fabrication of well-ordered TiO₂/CoO NTs from a Ti-Co alloy, followed by growing of CNTs horizontally on the top of the oxide films using a simple spray pyrolysis technique. The unique 1D structure of such a hybrid nanostructure with the inclusion of CNTs demonstrates significantly enhanced areal capacity and rate performances compared to pure TiO₂ and TiO₂/CoO NTs, without CNTs tested under identical conditions. The findings reveal that CNTs provide a highly conductive network that improves Li⁺ ion diffusivity, promoting a strongly favored lithium insertion into the TiO₂/CoO NT framework, and hence resulting in high capacity and an extremely reproducible high rate capability.

  9. Ternary CNTs@TiO2/CoO Nanotube Composites: Improved Anode Materials for High Performance Lithium Ion Batteries

    Science.gov (United States)

    Madian, Mahmoud; Ummethala, Raghunandan; Abo El Naga, Ahmed Osama; Ismail, Nahla; Rümmeli, Mark Hermann; Eychmüller, Alexander; Giebeler, Lars

    2017-01-01

    TiO2 nanotubes (NTs) synthesized by electrochemical anodization are discussed as very promising anodes for lithium ion batteries, owing to their high structural stability, high surface area, safety, and low production cost. However, their poor electronic conductivity and low Li+ ion diffusivity are the main drawbacks that prevent them from achieving high electrochemical performance. Herein, we report the fabrication of a novel ternary carbon nanotubes (CNTs)@TiO2/CoO nanotubes composite by a two-step synthesis method. The preparation includes an initial anodic fabrication of well-ordered TiO2/CoO NTs from a Ti-Co alloy, followed by growing of CNTs horizontally on the top of the oxide films using a simple spray pyrolysis technique. The unique 1D structure of such a hybrid nanostructure with the inclusion of CNTs demonstrates significantly enhanced areal capacity and rate performances compared to pure TiO2 and TiO2/CoO NTs, without CNTs tested under identical conditions. The findings reveal that CNTs provide a highly conductive network that improves Li+ ion diffusivity, promoting a strongly favored lithium insertion into the TiO2/CoO NT framework, and hence resulting in high capacity and an extremely reproducible high rate capability. PMID:28773032

  10. Ternary CNTs@TiO2/CoO Nanotube Composites: Improved Anode Materials for High Performance Lithium Ion Batteries

    Directory of Open Access Journals (Sweden)

    Mahmoud Madian

    2017-06-01

    Full Text Available TiO2 nanotubes (NTs synthesized by electrochemical anodization are discussed as very promising anodes for lithium ion batteries, owing to their high structural stability, high surface area, safety, and low production cost. However, their poor electronic conductivity and low Li+ ion diffusivity are the main drawbacks that prevent them from achieving high electrochemical performance. Herein, we report the fabrication of a novel ternary carbon nanotubes (CNTs@TiO2/CoO nanotubes composite by a two-step synthesis method. The preparation includes an initial anodic fabrication of well-ordered TiO2/CoO NTs from a Ti-Co alloy, followed by growing of CNTs horizontally on the top of the oxide films using a simple spray pyrolysis technique. The unique 1D structure of such a hybrid nanostructure with the inclusion of CNTs demonstrates significantly enhanced areal capacity and rate performances compared to pure TiO2 and TiO2/CoO NTs, without CNTs tested under identical conditions. The findings reveal that CNTs provide a highly conductive network that improves Li+ ion diffusivity, promoting a strongly favored lithium insertion into the TiO2/CoO NT framework, and hence resulting in high capacity and an extremely reproducible high rate capability.

  11. High-resolution 13C nuclear magnetic resonance evidence of phase transition of Rb,Cs-intercalated single-walled nanotubes

    KAUST Repository

    Bouhrara, M.; Saih, Y.; Wågberg, T.; Goze-Bac, C.; Abou-Hamad, E.

    2011-01-01

    charge transfer is applicable at low intercalation level. The new phase at high intercalation level is accompanied by a hybridization of alkali (s) orbitals with the carbon (sp2) orbitals of the single walled nanotubes, which indicate bundle surface sites

  12. Reactive bonding mediated high mass loading of individualized single-walled carbon nanotubes in an elastomeric polymer

    Science.gov (United States)

    Zhao, Liping; Li, Yongjin; Qiu, Jishan; You, Jichun; Dong, Wenyong; Cao, Xiaojun

    2012-09-01

    A reactive chemical bonding strategy was developed for the incorporation of a high mass loading of individual single-wall carbon nanotubes (SWCNTs) into an elastomeric matrix using a reactive ionic liquid as a linker. This method simultaneously prevented the agglomeration of SWCNTs and caused strong interfacial bonding, while the electronic properties of the SWCNTs remained intact. As a result, the high conductivity of the carbon nanotubes (CNTs) and the flexibility of the elastomeric matrix were retained, producing optimum electrical and mechanical properties. A composite material with a loading of 20 wt% SWCNTs was fabricated with excellent mechanical properties and a high conductivity (9500 S m-1). The method could be used to form transparent thin conductive films that could tolerate over 800 bend cycles at a bending angle of 180° while maintaining a constant sheet resistance.A reactive chemical bonding strategy was developed for the incorporation of a high mass loading of individual single-wall carbon nanotubes (SWCNTs) into an elastomeric matrix using a reactive ionic liquid as a linker. This method simultaneously prevented the agglomeration of SWCNTs and caused strong interfacial bonding, while the electronic properties of the SWCNTs remained intact. As a result, the high conductivity of the carbon nanotubes (CNTs) and the flexibility of the elastomeric matrix were retained, producing optimum electrical and mechanical properties. A composite material with a loading of 20 wt% SWCNTs was fabricated with excellent mechanical properties and a high conductivity (9500 S m-1). The method could be used to form transparent thin conductive films that could tolerate over 800 bend cycles at a bending angle of 180° while maintaining a constant sheet resistance. Electronic supplementary information (ESI) available: Conductivity test of the SEBS-SWCNTs film, transmission spectra and sheet resistance for the spin-coated SEBS-SWCNTs thin films on PET slides. See DOI: 10

  13. Carbon nanotube ensembled hybrid nanocomposite electrode for direct electrochemical detection of epinephrine in pharmaceutical tablets and urine.

    Science.gov (United States)

    Koteshwara Reddy, K; Satyanarayana, M; Yugender Goud, K; Vengatajalabathy Gobi, K; Kim, Hern

    2017-10-01

    An efficient electrochemical sensor for selective detection of the neurotransmitter, epinephrine (Epn), has been fabricated with the aid of a functionalized multiwall carbon nanotube-chitosan biopolymer nanocomposite (Chit-fCNT) electrode. Multiwall carbon nanotubes (CNT) were successfully functionalized with the aid of nitric acid and confirmed by the Raman spectral data. Functionalized carbon nanotubes (fCNT) were dispersed in chitosan solution and the resulting bio-nanocomposite was used for the fabrication of sensor surface by drop and cast method. Electrochemical characteristics of the fabricated sensor were understood using cyclic, differential pulse voltammetry (CV, DPV) and electrochemical impedance analysis for the detection of Epn in phosphate buffer (pH7.4). CV and impedance analysis revealed that the Chit-fCNT modified electrode enhances the electrodic reaction of Epn and facilitated the electron transfer more readily compared to that of bare electrode. Applying DPV for the detection of Epn, achieved 30nM as the lowest detection limit in the determination range of 0.05-10μM and the analytical time as low as 10s. Selective determination of Epn against the coexistence of a number of biological electroactive interferents and reproducible results for the determination of Epn were demonstrated. The present biosensor has been found efficient for successful direct determination of Epn from pharmaceutical adrenaline formulations and urine samples. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Room temperature synthesis of indium tin oxide nanotubes with high precision wall thickness by electroless deposition

    Directory of Open Access Journals (Sweden)

    Mario Boehme

    2011-02-01

    Full Text Available Conductive nanotubes consisting of indium tin oxide (ITO were fabricated by electroless deposition using ion track etched polycarbonate templates. To produce nanotubes (NTs with thin walls and small surface roughness, the tubes were generated by a multi-step procedure under aqueous conditions. The approach reported below yields open end nanotubes with well defined outer diameter and wall thickness. In the past, zinc oxide films were mostly preferred and were synthesized using electroless deposition based on aqueous solutions. All these methods previously developed, are not adaptable in the case of ITO nanotubes, even with modifications. In the present work, therefore, we investigated the necessary conditions for the growth of ITO-NTs to achieve a wall thickness of around 10 nm. In addition, the effects of pH and reductive concentrations for the formation of ITO-NTs are also discussed.

  15. Network single-walled carbon nanotube biosensors for fast and highly sensitive detection of proteins

    International Nuclear Information System (INIS)

    Hu Pingan; Zhang Jia; Wen Zhenzhong; Zhang Can

    2011-01-01

    Detection of proteins is powerfully assayed in the diagnosis of diseases. A strategy for the development of an ultrahigh sensitivity biosensor based on a network single-walled carbon nanotube (SWNT) field-effect transistor (FET) has been demonstrated. Metallic SWNTs (m-SWNTs) in the network nanotube FET were selectively removed or cut via a carefully controlled procedure of electrical break-down (BD), and left non-conducting m-SWNTs which magnified the Schottky barrier (SB) area. This nanotube FET exhibited ultrahigh sensitivity and fast response to biomolecules. The lowest detection limit of 0.5 pM was achieved by exploiting streptavidin (SA) or a biotin/SA pair as the research model, and BD-treated nanotube biosensors had a 2 x 10 4 -fold lower minimum detectable concentration than the device without BD treatment. The response time is in the range of 0.3-3 min.

  16. Preparation and elementary research on electrocatalytic hydrogen evolution of highly ordered titanium dioxide nanotube arrays

    International Nuclear Information System (INIS)

    Wu Qinglong; Liao Junsheng; Bai Yun

    2010-01-01

    Well ordered and uniform titanium dioxide nanotube arrays were fabricated by anodiaing process from a bath containing 1% NaF, 1mol/L Na 2 SO 4 , 0.5 mol/L H 2 SO 4 at room temperature. Surface morphology of titanium dioxide nanotube arrays were observed with SEM. The formation process of titanium dioxide nanotube arrays was suggested by current-time transient. Its catalytic hydrogen evolution behavior was studied by electrochemical measurements in a 5%(mass fraction) H 2 SO 4 solution. The results showed that the titanium dioxide nanotube arrays on titanium had better hydrogen evolution activity and trace palladium lead to the maximum electrocatalytic activity of hydrogen production. (authors)

  17. Stretchable carbon nanotube/ion-gel supercapacitors with high durability realized through interfacial microroughness.

    Science.gov (United States)

    Lee, Jiho; Kim, Wonbin; Kim, Woong

    2014-08-27

    A critical problem with stretchable supercapacitors developed to date has been evaporation of a volatile component of their electrolyte, causing failure. In this work, we demonstrated successful use of an ionic-liquid-based nonvolatile gel (ion-gel) electrolyte in carbon nanotube (CNT)-based stretchable supercapacitors. The CNT/ion-gel supercapacitors showed high capacitance retention (96.6%) over 3000 stretch cycles at 20% strain. The high durability against stretch cycles was achieved by introducing microroughness at the interfaces between different materials. The microroughness was produced by the simple process of imprinting the surface microstructure of office paper onto a poly(dimethylsiloxane) substrate; the surface texture is reproduced in successive current collector and CNT layers. Adhesion between the different layers was strengthened by this roughness and prevented delamination over repeated stretch cycles. The addition of a CNT layer decreased the sensitivity of electrical characteristics to stretching. Moreover, the ion-gel increases the operating voltage window (3 V) and hence the energy density. We believe our demonstration will greatly contribute to the development of flexible and/or stretchable energy-storage devices with high durability.

  18. Hierarchical, porous CuS microspheres integrated with carbon nanotubes for high-performance supercapacitors

    Science.gov (United States)

    Lu, Yang; Liu, Xianming; Wang, Weixiao; Cheng, Jinbing; Yan, Hailong; Tang, Chengchun; Kim, Jang-Kyo; Luo, Yongsong

    2015-11-01

    Carbon nanotubes (CNTs) incorporated porous 3-dimensional (3D) CuS microspheres have been successfully synthesized via a simple refluxing method assisted by PVP. The composites are composed of flower-shaped CuS secondary microspheres, which in turn are assembled with primary nanosheets of 15-30 nm in thickness and fully integrated with CNT. The composites possess a large specific surface area of 189.6 m2 g-1 and a high conductivity of 0.471 S cm-1. As electrode materials for supercapacitors, the nanocomposites show excellent cyclability and rate capability and deliver an average reversible capacitance as high as 1960 F g-1 at a current density of 10 mA cm-2 over 10000 cycles. The high electrochemical performance can be attributed to the synergistic effect of CNTs and the unique microstructure of CuS. The CNTs serve as not only a conductive agent to accelerate the transfer of electrons in the composites, but also as a buffer matrix to restrain the volume change and stabilize the electrode structure during the charge/discharge process. The porous structure of CuS also helps to stabilize the electrode structure and facilitates the transport for electrons.

  19. High Performance Carbon Nanotube Yarn Supercapacitors with a Surface-Oxidized Copper Current Collector.

    Science.gov (United States)

    Zhang, Daohong; Wu, Yunlong; Li, Ting; Huang, Yin; Zhang, Aiqing; Miao, Menghe

    2015-11-25

    Threadlike linear supercapacitors have demonstrated high potential for constructing fabrics to power electronic textiles (eTextiles). To improve the cyclic electrochemical performance and to produce power fabrics large enough for practical applications, a current collector has been introduced into the linear supercapcitors to transport charges produced by active materials along the length of the supercapacitor with high efficiency. Here, we first screened six candidate metal filaments (Pt, Au, Ag, AuAg, PtCu, and Cu) as current collectors for carbon nanotube (CNT) yarn-based linear supercapacitors. Although all of the metal filaments significantly improved the electrochemical performance of the linear supercapacitor, two supercapacitors constructed from Cu and PtCu filaments, respectively, demonstrate far better electrochemical performance than the other four supercapacitors. Further investigation shows that the surfaces of the two Cu-containing filaments are oxidized by the surrounding polymer electrolyte in the electrode. While the unoxidized core of the Cu-containing filaments remains highly conductive and functions as a current collector, the resulting CuO on the surface is an electrochemically active material. The linear supercapacitor architecture incorporating dual active materials CNT + Cu extends the potential window from 1.0 to 1.4 V, leading to significant improvement to the energy density and power density.

  20. Highly flexible, all solid-state micro-supercapacitors from vertically aligned carbon nanotubes.

    Science.gov (United States)

    Hsia, Ben; Marschewski, Julian; Wang, Shuang; In, Jung Bin; Carraro, Carlo; Poulikakos, Dimos; Grigoropoulos, Costas P; Maboudian, Roya

    2014-02-07

    We report a highly flexible planar micro-supercapacitor with interdigitated finger electrodes of vertically aligned carbon nanotubes (VACNTs). The planar electrode structures are patterned on a thin polycarbonate substrate with a facile, maskless laser-assisted dry transfer method. Sputtered Ni is used to reduce the in-plane resistance of the VACNT electrodes. An ionogel, an ionic liquid in a semi-solid matrix, is used as an electrolyte to form a fully solid-state device. We measure a specific capacitance of 430 μF cm(-2) for a scan rate of 0.1 V s(-1) and achieve rectangular cyclic voltammograms at high scan rates of up to 100 V s(-1). Minimal change in capacitance is observed under bending. Mechanical fatigue tests with more than 1000 cycles confirm the high flexibility and durability of the novel material combination chosen for this device. Our results indicate that this scalable and facile fabrication technique shows promise for application in integrated energy storage for all solid-state flexible microdevices.

  1. High-performance field emission device utilizing vertically aligned carbon nanotubes-based pillar architectures

    Science.gov (United States)

    Gupta, Bipin Kumar; Kedawat, Garima; Gangwar, Amit Kumar; Nagpal, Kanika; Kashyap, Pradeep Kumar; Srivastava, Shubhda; Singh, Satbir; Kumar, Pawan; Suryawanshi, Sachin R.; Seo, Deok Min; Tripathi, Prashant; More, Mahendra A.; Srivastava, O. N.; Hahm, Myung Gwan; Late, Dattatray J.

    2018-01-01

    The vertical aligned carbon nanotubes (CNTs)-based pillar architectures were created on laminated silicon oxide/silicon (SiO2/Si) wafer substrate at 775 °C by using water-assisted chemical vapor deposition under low pressure process condition. The lamination was carried out by aluminum (Al, 10.0 nm thickness) as a barrier layer and iron (Fe, 1.5 nm thickness) as a catalyst precursor layer sequentially on a silicon wafer substrate. Scanning electron microscope (SEM) images show that synthesized CNTs are vertically aligned and uniformly distributed with a high density. The CNTs have approximately 2-30 walls with an inner diameter of 3-8 nm. Raman spectrum analysis shows G-band at 1580 cm-1 and D-band at 1340 cm-1. The G-band is higher than D-band, which indicates that CNTs are highly graphitized. The field emission analysis of the CNTs revealed high field emission current density (4mA/cm2 at 1.2V/μm), low turn-on field (0.6 V/μm) and field enhancement factor (6917) with better stability and longer lifetime. Emitter morphology resulting in improved promising field emission performances, which is a crucial factor for the fabrication of pillared shaped vertical aligned CNTs bundles as practical electron sources.

  2. High-performance field emission device utilizing vertically aligned carbon nanotubes-based pillar architectures

    Directory of Open Access Journals (Sweden)

    Bipin Kumar Gupta

    2018-01-01

    Full Text Available The vertical aligned carbon nanotubes (CNTs-based pillar architectures were created on laminated silicon oxide/silicon (SiO2/Si wafer substrate at 775 °C by using water-assisted chemical vapor deposition under low pressure process condition. The lamination was carried out by aluminum (Al, 10.0 nm thickness as a barrier layer and iron (Fe, 1.5 nm thickness as a catalyst precursor layer sequentially on a silicon wafer substrate. Scanning electron microscope (SEM images show that synthesized CNTs are vertically aligned and uniformly distributed with a high density. The CNTs have approximately 2–30 walls with an inner diameter of 3–8 nm. Raman spectrum analysis shows G-band at 1580 cm−1 and D-band at 1340 cm−1. The G-band is higher than D-band, which indicates that CNTs are highly graphitized. The field emission analysis of the CNTs revealed high field emission current density (4mA/cm2 at 1.2V/μm, low turn-on field (0.6 V/μm and field enhancement factor (6917 with better stability and longer lifetime. Emitter morphology resulting in improved promising field emission performances, which is a crucial factor for the fabrication of pillared shaped vertical aligned CNTs bundles as practical electron sources.

  3. High-performance supercapacitors using a nanoporous current collector made from super-aligned carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Zhou Ruifeng; Meng Chuizhou; Zhu Feng; Li Qunqing; Liu Changhong; Fan Shoushan; Jiang Kaili, E-mail: JiangKL@tsinghua.edu.cn [Department of Physics and Tsinghua-Foxconn Nanotechnology Research Center, Tsinghua University, Beijing 100084 (China)

    2010-08-27

    Nanoporous current collectors for supercapacitors have been fabricated by cross-stacking super-aligned carbon nanotube (SACNT) films as a replacement for heavy conventional metallic current collectors. The CNT-film current collectors have good conductivity, extremely low density (27 {mu}g cm{sup -2}), high specific surface area, excellent flexibility and good electrochemical stability. Nanosized active materials such as NiO, Co{sub 3}O{sub 4} or Mn{sub 2}O{sub 3} nanoparticles can be directly synthesized on the SACNT films by a straightforward one-step, in situ decomposition strategy that is both efficient and environmentally friendly. These composite films can be integrated into a pseudo-capacitor that does not use metallic current collectors, but nevertheless shows very good performance, including high specific capacitance ({approx}500 F g{sup -1}, including the current collector mass), reliable electrochemical stability (<4.5% degradation in 2500 cycles) and a very high rate capability (245 F g{sup -1} at 155 A g{sup -1}).

  4. Highly Uniform Carbon Nanotube Field-Effect Transistors and Medium Scale Integrated Circuits.

    Science.gov (United States)

    Chen, Bingyan; Zhang, Panpan; Ding, Li; Han, Jie; Qiu, Song; Li, Qingwen; Zhang, Zhiyong; Peng, Lian-Mao

    2016-08-10

    Top-gated p-type field-effect transistors (FETs) have been fabricated in batch based on carbon nanotube (CNT) network thin films prepared from CNT solution and present high yield and highly uniform performance with small threshold voltage distribution with standard deviation of 34 mV. According to the property of FETs, various logical and arithmetical gates, shifters, and d-latch circuits were designed and demonstrated with rail-to-rail output. In particular, a 4-bit adder consisting of 140 p-type CNT FETs was demonstrated with higher packing density and lower supply voltage than other published integrated circuits based on CNT films, which indicates that CNT based integrated circuits can reach to medium scale. In addition, a 2-bit multiplier has been realized for the first time. Benefitted from the high uniformity and suitable threshold voltage of CNT FETs, all of the fabricated circuits based on CNT FETs can be driven by a single voltage as small as 2 V.

  5. High performance dendrimer functionalized single-walled carbon nanotubes field effect transistor biosensor for protein detection

    Science.gov (United States)

    Rajesh, Sharma, Vikash; Puri, Nitin K.; Mulchandani, Ashok; Kotnala, Ravinder K.

    2016-12-01

    We report a single-walled carbon nanotube (SWNT) field-effect transistor (FET) functionalized with Polyamidoamine (PAMAM) dendrimer with 128 carboxyl groups as anchors for site specific biomolecular immobilization of protein antibody for C-reactive protein (CRP) detection. The FET device was characterized by scanning electron microscopy and current-gate voltage (I-Vg) characteristic studies. A concentration-dependent decrease in the source-drain current was observed in the regime of clinical significance, with a detection limit of ˜85 pM and a high sensitivity of 20% change in current (ΔI/I) per decade CRP concentration, showing SWNT being locally gated by the binding of CRP to antibody (anti-CRP) on the FET device. The low value of the dissociation constant (Kd = 0.31 ± 0.13 μg ml-1) indicated a high affinity of the device towards CRP analyte arising due to high anti-CRP loading with a better probe orientation on the 3-dimensional PAMAM structure.

  6. Graphene-based supercapacitor with carbon nanotube film as highly efficient current collector

    International Nuclear Information System (INIS)

    Notarianni, Marco; Liu, Jinzhang; Motta, Nunzio; Mirri, Francesca; Pasquali, Matteo

    2014-01-01

    Flexible graphene-based thin film supercapacitors were made using carbon nanotube (CNT) films as current collectors and graphene films as electrodes. The graphene sheets were produced by simple electrochemical exfoliation, while the graphene films with controlled thickness were prepared by vacuum filtration. The solid-state supercapacitor was made by using two graphene/CNT films on plastic substrates to sandwich a thin layer of gelled electrolyte. We found that the thin graphene film with thickness <1 μm can greatly increase the capacitance. Using only CNT films as electrodes, the device exhibited a capacitance as low as ∼0.4 mF cm −2 , whereas by adding a 360 nm thick graphene film to the CNT electrodes led to a ∼4.3 mF cm −2 capacitance. We experimentally demonstrated that the conductive CNT film is equivalent to gold as a current collector while it provides a stronger binding force to the graphene film. Combining the high capacitance of the thin graphene film and the high conductivity of the CNT film, our devices exhibited high energy density (8–14 Wh kg −1 ) and power density (250–450 kW kg −1 ). (paper)

  7. Highly Selective Photothermal Therapy by a Phenoxylated-Dextran-Functionalized Smart Carbon Nanotube Platform.

    Science.gov (United States)

    Han, Seungmin; Kwon, Taeyun; Um, Jo-Eun; Haam, Seungjoo; Kim, Woo-Jae

    2016-05-01

    Near-infrared (NIR) photothermal therapy using biocompatible single-walled carbon nanotubes (SWNTs) is advantageous because as-produced SWNTs, without additional size control, both efficiently absorb NIR light and demonstrate high photothermal conversion efficiency. In addition, covalent attachment of receptor molecules to SWNTs can be used to specifically target infected cells. However, this technique interrupts SWNT optical properties and inevitably lowers photothermal conversion efficiency and thus remains major hurdle for SWNT applications. This paper presents a smart-targeting photothermal therapy platform for inflammatory disease using newly developed phenoxylated-dextran-functionalized SWNTs. Phenoxylated dextran is biocompatible and efficiently suspends SWNTs by noncovalent π-π stacking, thereby minimizing SWNT bundle formations and maintaining original SWNT optical properties. Furthermore, it selectively targets inflammatory macrophages by scavenger-receptor binding without any additional receptor molecules; therefore, its preparation is a simple one-step process. Herein, it is experimentally demonstrated that phenoxylated dextran-SWNTs (pD-SWNTs) are also biocompatible, selectively penetrate inflammatory macrophages over normal cells, and exhibit high photothermal conversion efficiency. Consequently, NIR laser-triggered macrophage treatment can be achieved with high accuracy by pD-SWNT without damaging receptor-free cells. These smart targeting materials can be a novel photothermal agent candidate for inflammatory disease. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Graphene Carbon Nanotube Carpets Grown Using Binary Catalysts for High-Performance Lithium-Ion Capacitors.

    Science.gov (United States)

    Salvatierra, Rodrigo Villegas; Zakhidov, Dante; Sha, Junwei; Kim, Nam Dong; Lee, Seoung-Ki; Raji, Abdul-Rahman O; Zhao, Naiqin; Tour, James M

    2017-03-28

    Here we show that a versatile binary catalyst solution of Fe 3 O 4 /AlO x nanoparticles enables homogeneous growth of single to few-walled carbon nanotube (CNT) carpets from three-dimensional carbon-based substrates, moving past existing two-dimensional limited growth methods. The binary catalyst is composed of amorphous AlO x nanoclusters over Fe 3 O 4 crystalline nanoparticles, facilitating the creation of seamless junctions between the CNTs and the underlying carbon platform. The resulting graphene-CNT (GCNT) structure is a high-density CNT carpet ohmically connected to the carbon substrate, an important feature for advanced carbon electronics. As a demonstration of the utility of this approach, we use GCNTs as anodes and cathodes in binder-free lithium-ion capacitors, producing stable devices with high-energy densities (∼120 Wh kg -1 ), high-power density capabilities (∼20,500 W kg -1 at 29 Wh kg -1 ), and a large operating voltage window (4.3 to 0.01 V).

  9. High performance, freestanding and superthin carbon nanotube/epoxy nanocomposite films.

    Science.gov (United States)

    Li, Jinzhu; Gao, Yun; Ma, Wenjun; Liu, Luqi; Zhang, Zhong; Niu, Zhiqiang; Ren, Yan; Zhang, Xiaoxian; Zeng, Qingshen; Dong, Haibo; Zhao, Duan; Cai, Le; Zhou, Weiya; Xie, Sishen

    2011-09-01

    We develop a facile, effective and filter free infiltration method to fabricate high performance, freestanding and superthin epoxy nanocomposite films with directly synthesized Sing-Walled Carbon Nanotubes (SWNTs) film as reinforcement skeleton. It is found that the thicknesses of the nanocomposite films can be easily controlled in the range of 0.5-3 μm by dripping target amount of acetone diluted epoxy through the skeleton film. The consequent measurements reveal that the mechanical and electrical properties of SWNTs/epoxy nanocomposite films could be tailored in a quite wide range. For examples, the Young's modulus of nanocomposite films can be tuned from 10 to 30 GPa, and the electrical conductivity can be ranged from 1000 S·cm(-1) to be insulated. Moreover, high load transfer efficiency in the nanocomposite films is demonstrated by the measured ultrahigh Raman bands shift rate (-30 ± 5 cm(-1)/% strain) under strain. The high effective modulus is derived as 774 ± 70 GPa for SWNTs inside this nanocomposite film.

  10. Demonstration of high current carbon nanotube enabled vertical organic field effect transistors at industrially relevant voltages

    Science.gov (United States)

    McCarthy, Mitchell

    The display market is presently dominated by the active matrix liquid crystal display (LCD). However, the active matrix organic light emitting diode (AMOLED) display is argued to become the successor to the LCD, and is already beginning its way into the market, mainly in small size displays. But, for AMOLED technology to become comparable in market share to LCD, larger size displays must become available at a competitive price with their LCD counterparts. A major issue preventing low-cost large AMOLED displays is the thin-film transistor (TFT) technology. Unlike the voltage driven LCD, the OLEDs in the AMOLED display are current driven. Because of this, the mature amorphous silicon TFT backplane technology used in the LCD must be upgraded to a material possessing a higher mobility. Polycrystalline silicon and transparent oxide TFT technologies are being considered to fill this need. But these technologies bring with them significant manufacturing complexity and cost concerns. Carbon nanotube enabled vertical organic field effect transistors (CN-VFETs) offer a unique solution to this problem (now known as the AMOLED backplane problem). The CN-VFET allows the use of organic semiconductors to be used for the semiconductor layer. Organics are known for their low-cost large area processing compatibility. Although the mobility of the best organics is only comparable to that of amorphous silicon, the CN-VFET makes up for this by orienting the channel vertically, as opposed to horizontally (like in conventional TFTs). This allows the CN-VFET to achieve sub-micron channel lengths without expensive high resolution patterning. Additionally, because the CN-VFET can be easily converted into a light emitting transistor (called the carbon nanotube enabled vertical organic light emitting transistor---CN-VOLET) by essentially stacking an OLED on top of the CN-VFET, more potential benefits can be realized. These potential benefits include, increased aperture ratio, increased OLED

  11. Highly selective and sensitive detection of neurotransmitters using receptor-modified single-walled carbon nanotube sensors

    Science.gov (United States)

    Kim, Byeongju; Song, Hyun Seok; Jin, Hye Jun; Park, Eun Jin; Lee, Sang Hun; Lee, Byung Yang; Park, Tai Hyun; Hong, Seunghun

    2013-07-01

    We present receptor-modified carbon nanotube sensors for the highly selective and sensitive detection of acetylcholine (ACh), one kind of neurotransmitter. Here, we successfully expressed the M1 muscarinic acetylcholine receptor (M1 mAChR), a family of G protein-coupled receptors (GPCRs), in E. coli and coated single-walled carbon nanotube (swCNT)-field effect transistors (FETs) with lipid membrane including the receptor, enabling highly selective and sensitive ACh detection. Using this sensor, we could detect ACh at 100 pM concentration. Moreover, we showed that this sensor could selectively detect ACh among other neurotransmitters. This is the first demonstration of the real-time detection of ACh using specific binding between ACh and M1 mAChR, and it may lead to breakthroughs for various applications such as disease diagnosis and drug screening.

  12. Highly selective and sensitive detection of neurotransmitters using receptor-modified single-walled carbon nanotube sensors

    International Nuclear Information System (INIS)

    Kim, Byeongju; Jin, Hye Jun; Park, Eun Jin; Hong, Seunghun; Song, Hyun Seok; Lee, Sang Hun; Park, Tai Hyun; Lee, Byung Yang

    2013-01-01

    We present receptor-modified carbon nanotube sensors for the highly selective and sensitive detection of acetylcholine (ACh), one kind of neurotransmitter. Here, we successfully expressed the M1 muscarinic acetylcholine receptor (M1 mAChR), a family of G protein-coupled receptors (GPCRs), in E. coli and coated single-walled carbon nanotube (swCNT)-field effect transistors (FETs) with lipid membrane including the receptor, enabling highly selective and sensitive ACh detection. Using this sensor, we could detect ACh at 100 pM concentration. Moreover, we showed that this sensor could selectively detect ACh among other neurotransmitters. This is the first demonstration of the real-time detection of ACh using specific binding between ACh and M1 mAChR, and it may lead to breakthroughs for various applications such as disease diagnosis and drug screening. (paper)

  13. Stable and solid pellets of functionalized multi-walled carbon nanotubes produced under high pressure and temperature

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Pâmela Andréa Mantey dos [Universidade Federal do Rio Grande do Sul, UFRGS, Programa de Pós-Graduação em Ciência dos Materiais (Brazil); Gallas, Marcia Russman [Universidade Federal do Rio Grande do Sul, UFRGS, Instituto de Física (Brazil); Radtke, Cláudio; Benvenutti, Edilson Valmir [Universidade Federal do Rio Grande do Sul, UFRGS, Instituto de Química (Brazil); Elias, Ana Laura [The Pennsylvania State University, Department of Physics and Center for 2-D and Layered Materials (United States); Rajukumar, Lakshmy Pulickal [The Pennsylvania State University, Department of Materials Science and Engineering (United States); Terrones, Humberto [Rensselaer Polytechnic Institute, Department of Physics, Applied Physics and Astronomy (United States); Endo, Morinobu [Shinshu University, Carbon Institute of Science and Technology (Japan); Terrones, Mauricio [The Pennsylvania State University, Department of Physics and Center for 2-D and Layered Materials (United States); Costa, Tania Maria Haas, E-mail: taniaha@iq.ufrgs.br, E-mail: taniahac@gmail.com [Universidade Federal do Rio Grande do Sul, UFRGS, Programa de Pós-Graduação em Ciência dos Materiais (Brazil)

    2015-06-15

    High pressure/temperature was applied on samples of pristine multi-walled carbon nanotubes (MWCNT), functionalized nanotubes (f-MWCNT), and nanotubes doped with nitrogen (CN{sub x}MWNT). Cylindrical compact pellets of f-MWCNT with diameters of about 6 mm were obtained under pressure of 4.0 GPa at room temperature and at 400 °C, using graphite as pressure transmitting medium. The best pellet samples were produced using nitric and sulfuric acids for the functionalization of MWCNT. The effect of high pressure/temperature on CNT was investigated by several spectroscopy and characterization techniques, such as Raman spectroscopy, X-ray powder diffraction, X-ray photoelectron spectroscopy, N{sub 2} adsorption/desorption isotherms, and transmission electron microscopy. It was found that MWCNT maintain their main features in the compacted pellets, such as integrity, original morphology, and structure, demonstrating that high-pressure/temperature compaction can indeed be used to fabricate novel CNT self-supported materials. Additionally, the specific surface area and porosity are unchanged, which is important when using bulk CNT in adsorption processes. Raman analysis of the G’-band showed a shift to lower wavenumbers when f-MWCNT were processed under high pressure, suggesting that CNT are under tensile stress.

  14. Highly ordered and ultra-long carbon nanotube arrays as air cathodes for high-energy-efficiency Li-oxygen batteries

    Science.gov (United States)

    Yu, Ruimin; Fan, Wugang; Guo, Xiangxin; Dong, Shaoming

    2016-02-01

    Carbonaceous air cathodes with rational architecture are vital for the nonaqueous Li-O2 batteries to achieve large energy density, high energy efficiency and long cycle life. In this work, we report the cathodes made of highly ordered and vertically aligned carbon nanotubes grown on permeable Ta foil substrates (VACNTs-Ta) via thermal chemical vapour deposition. The VACNTs-Ta, composed of uniform carbon nanotubes with approximately 240 μm in superficial height, has the super large surface area. Meanwhile, the oriented carbon nanotubes provide extremely outstanding passageways for Li ions and oxygen species. Electrochemistry tests of VACNTs-Ta air cathodes show enhancement in discharge capacity and cycle life compared to those made from short-range oriented and disordered carbon nanotubes. By further combining with the LiI redox mediator that is dissolved in the tetraethylene dimethyl glycol based electrolytes, the batteries exhibit more than 200 cycles at the current density of 200 mA g-1 with a cut-off discharge capacity of 1000 mAh g-1, and their energy efficiencies increase from 50% to 82%. The results here demonstrate the importance of cathode construction for high-energy-efficiency and long-life Li-O2 batteries.

  15. Soldering of Nanotubes onto Microelectrodes

    DEFF Research Database (Denmark)

    Madsen, Dorte Nørgaard; Mølhave, Kristian; Mateiu, Ramona Valentina

    2003-01-01

    Suspended bridges of individual multiwalled carbon nanotubes were fabricated inside a scanning electron microscope by soldering the nanotube onto microelectrodes with highly conducting gold-carbon material. By the decomposition of organometallic vapor with the electron beam, metal-containing sold...... bonds were consistently found to be mechanically stronger than the carbon nanotubes.......Suspended bridges of individual multiwalled carbon nanotubes were fabricated inside a scanning electron microscope by soldering the nanotube onto microelectrodes with highly conducting gold-carbon material. By the decomposition of organometallic vapor with the electron beam, metal-containing solder...... bonds were formed at the intersection of the nanotube and the electrodes. Current-voltage curves indicated metallic conduction of the nanotubes, with resistances in the range of 9-29 kOmega. Bridges made entirely of the soldering material exhibited resistances on the order of 100 Omega, and the solder...

  16. Electrical and Self-Sensing Properties of Ultra-High-Performance Fiber-Reinforced Concrete with Carbon Nanotubes

    OpenAIRE

    You, Ilhwan; Yoo, Doo-Yeol; Kim, Soonho; Kim, Min-Jae; Zi, Goangseup

    2017-01-01

    This study examined the electrical and self-sensing capacities of ultra-high-performance fiber-reinforced concrete (UHPFRC) with and without carbon nanotubes (CNTs). For this, the effects of steel fiber content, orientation, and pore water content on the electrical and piezoresistive properties of UHPFRC without CNTs were first evaluated. Then, the effect of CNT content on the self-sensing capacities of UHPFRC under compression and flexure was investigated. Test results indicated that higher ...

  17. Computational local stiffness analysis of biological cell: High aspect ratio single wall carbon nanotube tip

    Energy Technology Data Exchange (ETDEWEB)

    TermehYousefi, Amin, E-mail: at.tyousefi@gmail.com [Department of Human Intelligence Systems, Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology (Kyutech) (Japan); Bagheri, Samira; Shahnazar, Sheida [Nanotechnology & Catalysis Research Centre (NANOCAT), IPS Building, University Malaya, 50603 Kuala Lumpur (Malaysia); Rahman, Md. Habibur [Department of Computer Science and Engineering, University of Asia Pacific, Green Road, Dhaka-1215 (Bangladesh); Kadri, Nahrizul Adib [Department of Biomedical Engineering, Faculty of Engineering, University Malaya, 50603 Kuala Lumpur (Malaysia)

    2016-02-01

    Carbon nanotubes (CNTs) are potentially ideal tips for atomic force microscopy (AFM) due to the robust mechanical properties, nanoscale diameter and also their ability to be functionalized by chemical and biological components at the tip ends. This contribution develops the idea of using CNTs as an AFM tip in computational analysis of the biological cells. The proposed software was ABAQUS 6.13 CAE/CEL provided by Dassault Systems, which is a powerful finite element (FE) tool to perform the numerical analysis and visualize the interactions between proposed tip and membrane of the cell. Finite element analysis employed for each section and displacement of the nodes located in the contact area was monitored by using an output database (ODB). Mooney–Rivlin hyperelastic model of the cell allows the simulation to obtain a new method for estimating the stiffness and spring constant of the cell. Stress and strain curve indicates the yield stress point which defines as a vertical stress and plan stress. Spring constant of the cell and the local stiffness was measured as well as the applied force of CNT-AFM tip on the contact area of the cell. This reliable integration of CNT-AFM tip process provides a new class of high performance nanoprobes for single biological cell analysis. - Graphical abstract: This contribution develops the idea of using CNTs as an AFM tip in computational analysis of the biological cells. The proposed software was ABAQUS 6.13 CAE/CEL provided by Dassault Systems. Finite element analysis employed for each section and displacement of the nodes located in the contact area was monitored by using an output database (ODB). Mooney–Rivlin hyperelastic model of the cell allows the simulation to obtain a new method for estimating the stiffness and spring constant of the cell. Stress and strain curve indicates the yield stress point which defines as a vertical stress and plan stress. Spring constant of the cell and the local stiffness was measured as well

  18. Fabrication of high-performance supercapacitors based on transversely oriented carbon nanotubes

    Science.gov (United States)

    Markoulidis, F.; Lei, C.; Lekakou, C.

    2013-04-01

    High-performance supercapacitors with organic electrolyte 1 M TEABF4 (tetraethyl ammonium tetrafluoroborate) in PC (propylene carbonate) were fabricated and tested, based on multiwall carbon nanotubes (MWNTs) deposited by electrophoresis on three types of alternative substrates: aluminium foil, ITO (indium tin oxide) coated PET (polyethylene terephthalate) film and PET film. In all cases, SEM (scanning electron microscopy) and STEM (scanning transmission electron microscopy) micrographs demonstrated that protruding, transversely oriented MWNT structures were formed, which should increase the transverse conductivity of these MWNT electrodes. The best supercapacitor cell of MWNT electrodes deposited on aluminium foil displayed good transverse orientation of the MWNT structures as well as an in-plane MWNT network at the feet of the protruding structures, which ensured good in-plane conductivity. Capacitor cells with MWNT electrodes deposited either on ITO-coated PET film or on PET film demonstrated lower but still very good performance due to the high density of transversely oriented MWNT structures (good transverse conductivity) but some in-plane inhomogeneities. Capacitor cells with drop-printed MWNTs on aluminium foil, without any transverse orientation, had 16-30 times lower specific capacitance and 5-40 times lower power density than the capacitor cells with the electrophoretically deposited MWNT electrodes.

  19. Elastic-resilience-induced dispersion of carbon nanotubes: a novel way of fabricating high performance elastomer

    International Nuclear Information System (INIS)

    Wu, Siwu; Lin, Tengfei; Guo, Baochun

    2013-01-01

    State-of-the-art processes cannot achieve rubber/multi-walled carbon nanotube (MWCNT) composites with satisfactory performance by using pristine MWCNTs and conventional processing equipment. In this work, high performance rubber/MWCNT composites featuring a combination of good mechanical properties, electrical and thermal conductivities and damping capacity over a wide temperature range are fabricated based on a well-developed master batch process. It is demonstrated that the MWCNTs are dispersed homogeneously due to the disentanglement induced by well-wetting and shearing, and the elastic-resilience-induced dispersion of the MWCNTs by rubber chains via the novel processing method. To further enhance the efficacy of elastic-resilience-induced dispersion for MWCNTs, a slightly pre-crosslinked network is constructed in the master batch. Consequently, we obtain rubber/MWCNT composites with unprecedented performance by amplifying the reinforcing effect of relatively low MWCNT loading. This work provides a novel insight into the fabrication of high performance functional elastomeric composites with pristine CNTs by taking advantage of the unique elastic resilience of rubber chains as the driving force for the disentanglement of CNTs. (paper)

  20. Bio-Inspired Supramolecular Chemistry Provides Highly Concentrated Dispersions of Carbon Nanotubes in Polythiophene

    Directory of Open Access Journals (Sweden)

    Yen-Ting Lin

    2016-06-01

    Full Text Available In this paper we report the first observation, through X-ray diffraction, of noncovalent uracil–uracil (U–U dimeric π-stacking interactions in carbon nanotube (CNT–based supramolecular assemblies. The directionally oriented morphology determined using atomic force microscopy revealed highly organized behavior through π-stacking of U moieties in a U-functionalized CNT derivative (CNT–U. We developed a dispersion system to investigate the bio-inspired interactions between an adenine (A-terminated poly(3-adeninehexyl thiophene (PAT and CNT–U. These hybrid CNT–U/PAT materials interacted through π-stacking and multiple hydrogen bonding between the U moieties of CNT–U and the A moieties of PAT. Most importantly, the U···A multiple hydrogen bonding interactions between CNT–U and PAT enhanced the dispersion of CNT–U in a high-polarity solvent (DMSO. The morphology of these hybrids, determined using transmission electron microscopy, featured grape-like PAT bundles wrapped around the CNT–U surface; this tight connection was responsible for the enhanced dispersion of CNT–U in DMSO.

  1. Additive Manufacturing of Multifunctional Components Using High Density Carbon Nanotube Yarn Filaments

    Science.gov (United States)

    Gardner, John M.; Sauti, Godfrey; Kim, Jae-Woo; Cano, Roberto J.; Wincheski, Russell A.; Stelter, Christopher J.; Grimsley, Brian W.; Working, Dennis C.; Siochi, Emilie J.

    2016-01-01

    Additive manufacturing allows for design freedom and part complexity not currently attainable using traditional manufacturing technologies. Fused Filament Fabrication (FFF), for example, can yield novel component geometries and functionalities because the method provides a high level of control over material placement and processing conditions. This is achievable by extrusion of a preprocessed filament feedstock material along a predetermined path. However if fabrication of a multifunctional part relies only on conventional filament materials, it will require a different material for each unique functionality printed into the part. Carbon nanotubes (CNTs) are an attractive material for many applications due to their high specific strength as well as good electrical and thermal conductivity. The presence of this set of properties in a single material presents an opportunity to use one material to achieve multifunctionality in an additively manufactured part. This paper describes a recently developed method for processing continuous CNT yarn filaments into three-dimensional articles, and summarizes the mechanical, electrical, and sensing performance of the components fabricated in this way.

  2. Optimization of the sintering atmosphere for high-density hydroxyapatite–carbon nanotube composites

    Science.gov (United States)

    White, Ashley A.; Kinloch, Ian A.; Windle, Alan H.; Best, Serena M.

    2010-01-01

    Hydroxyapatite–carbon nanotube (HA–CNT) composites have the potential for improved mechanical properties over HA for use in bone graft applications. Finding an appropriate sintering atmosphere for this composite presents a dilemma, as HA requires water in the sintering atmosphere to remain phase pure and well hydroxylated, yet CNTs oxidize at the high temperatures required for sintering. The purpose of this study was to optimize the atmosphere for sintering these composites. While the reaction between carbon and water to form carbon monoxide and hydrogen at high temperatures (known as the ‘water–gas reaction’) would seem to present a problem for sintering these composites, Le Chatelier's principle suggests this reaction can be suppressed by increasing the concentration of carbon monoxide and hydrogen relative to the concentration of carbon and water, so as to retain the CNTs and keep the HA's structure intact. Eight sintering atmospheres were investigated, including standard atmospheres (such as air and wet Ar), as well as atmospheres based on the water–gas reaction. It was found that sintering in an atmosphere of carbon monoxide and hydrogen, with a small amount of water added, resulted in an optimal combination of phase purity, hydroxylation, CNT retention and density. PMID:20573629

  3. Porous SnO2-CuO nanotubes for highly reversible lithium storage

    Science.gov (United States)

    Cheong, Jun Young; Kim, Chanhoon; Jung, Ji-Won; Yoon, Ki Ro; Kim, Il-Doo

    2018-01-01

    Facile synthesis of rationally designed structures is critical to realize a high performance electrode for lithium-ion batteries (LIBs). Among different candidates, tin(IV) oxide (SnO2) is one of the most actively researched electrode materials due to its high theoretical capacity (1493 mAh g-1), abundance, inexpensive costs, and environmental friendliness. However, severe capacity decay from the volume expansion and low conductivity of SnO2 have hampered its use as a feasible electrode for LIBs. Rationally designed SnO2-based nanostructures with conductive materials can be an ideal solution to resolve such limitations. In this work, we have successfully fabricated porous SnO2-CuO composite nanotubes (SnO2-CuO p-NTs) by electrospinning and subsequent calcination step. The porous nanotubular structure is expected to mitigate the volume expansion of SnO2, while the as-formed Cu from CuO upon lithiation allows faster electron transport by improving the low conductivity of SnO2. With a synergistic effect of both Sn and Cu-based oxides, SnO2-CuO p-NTs deliver stable cycling performance (91.3% of capacity retention, ∼538 mAh g-1) even after 350 cycles at a current density of 500 mA g-1, along with enhanced rate capabilities compared with SnO2.

  4. Synthesis of high quality single-walled carbon nanotubes via a catalytic layer reinforced by self-assembled monolayers

    International Nuclear Information System (INIS)

    Adhikari, Prashanta Dhoj; Song, Wooseok; Cha, Myoung-Jun; Park, Chong-Yun

    2013-01-01

    This work reports the synthesis of high quality single-walled carbon nanotubes (SWCNT) using a catalytic layer reinforced by self-assembled monolayers (SAM). Amine-SAM was introduced on a SiO 2 /Si substrate and then an iron nanoparticles solution was dropped on the substrate by spin-coating. This catalytic template was used to grow carbon nanotubes by chemical vapor deposition and the synthesized SWCNT were observed to be prominent, based on the size distribution. Highly dense SWCNT with a diameter of about 1.1-1.2 nm were produced at 800-850 °C. Moreover, the diameter distribution of the SWCNT was more selective at a growth temperature of 900 °C. These findings provide important insights for a SAM support layer that can play the role as a restriction for the agglomeration of iron catalyst and is promising for the synthesis of high quality SWCNT. - Highlights: • Fe nanoparticles on self-assembled monolayers (SAM) containing template is underlined. • Its catalytic behavior to synthesis single-walled carbon nanotubes is studied. • The role of SAM on catalytic template is explored

  5. Facile fabrication of self-assembled polyaniline nanotubes doped with D-tartaric acid for high-performance supercapacitors

    Science.gov (United States)

    Mu, Jingjing; Ma, Guofu; Peng, Hui; Li, Jiajia; Sun, Kanjun; Lei, Ziqiang

    2013-11-01

    Polyaniline (PANI) nanotubes with outstanding electrochemical properties have been successfully synthesized via a simple chemical template-free method in the presence of D-tartaric acid (D-TA) as the dopant, and ammonium persulfate ((NH4)2S2O8) as the oxidant. The morphologies and structures of PANI-(D-TA) with different [D-TA]/[aniline] molar ratios are characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) and X-ray diffraction (XRD). To assess the electrochemical properties of PANI-(D-TA) materials, cyclic voltammetry (CV) and galvanostatic charging-discharging measurements are performed. The PANI-(D-TA) nanotubes electrode, with [D-TA]/[aniline] molar ratio of 1:1, exhibits larger specific capacitance (as high as 625 F g-1 at 1 A g-1) and higher capacitance retention (77% of its initial capacitance after 500 cycles) in 1 M H2SO4 aqueous solution. The remarkable electrochemical characteristics of PANI-(D-TA) are mainly attributed to their unique nanotubular structures, which provide a high electrode/electrolyte contact area and short ions diffusion path. These novel PANI-(D-TA) nanotubes will be promising electrode materials for high-performance supercapacitors.

  6. High quantum yield graphene quantum dots decorated TiO{sub 2} nanotubes for enhancing photocatalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Qu, Ailan, E-mail: qal67@163.com; Xie, Haolong; Xu, Xinmei; Zhang, Yangyu; Wen, Shengwu; Cui, Yifan

    2016-07-01

    Highlights: • High concentration yellow GQDs and TiO{sub 2} nanotubes were achieved by a simple and green method. • High quantum yield GQDs enhanced the photodegradation capacity of TiO{sub 2} nanotube. • The catalytic performance of GQDs/TiO{sub 2} depends on the GQDs loading. • The improved photocatalytic activity of GQDs/TiO{sub 2} was attributed to three aspects. - Abstract: Graphene quantum dots (GQDs) with high quantum yield (about 23.6% at an excitation wavelength of 320 nm) and GQDs/TiO{sub 2} nanotubes (GQDs/TiO{sub 2} NTs) composites were achieved by a simple hydrothermal method at low temperature. Photoluminescence characterization showed that the GQDs exhibited the down-conversion PL features at excitation from 300 to 420 nm and up-conversion photoluminescence in the range of 600–800 nm. The photocatalytic activity of prepared GQDs/TiO{sub 2} NTs composites on the degradation of methyl orange (MO) was significantly enhanced compared with that of pure TiO{sub 2} nanotubes (TiO{sub 2} NTs). For the composites coupling with 1.5%, 2.5% and 3.5% GQDs, the degradation of MO after 20 min irradiation under UV–vis light irradiation (λ = 380–780 nm) were 80.52%, 94.64% and 51.91%, respectively, which are much higher than that of pure TiO{sub 2} NTs (35.41%). It was inferred from the results of characterization that the improved photocatalytic activity of the GQDs/TiO{sub 2} NTs composites was attributed to the synergetic effect of up-conversion properties of the GQDs, enhanced visible light absorption and efficient separation of photogenerated electron-holes of the GQDs/TiO{sub 2} composite.

  7. Electron diffraction from carbon nanotubes

    International Nuclear Information System (INIS)

    Qin, L-C

    2006-01-01

    The properties of a carbon nanotube are dependent on its atomic structure. The atomic structure of a carbon nanotube can be defined by specifying its chiral indices (u, v), that specify its perimeter vector (chiral vector), with which the diameter and helicity are also determined. The fine electron beam available in a modern transmission electron microscope (TEM) offers a unique probe to reveal the atomic structure of individual nanotubes. This review covers two aspects related to the use of the electron probe in the TEM for the study of carbon nanotubes: (a) to understand the electron diffraction phenomena for inter-pretation of the electron diffraction patterns of carbon nanotubes and (b) to obtain the chiral indices (u, v), of the carbon nanotubes from the electron diffraction patterns. For a nanotube of a given structure, the electron scattering amplitude from the carbon nanotube is first described analytically in closed form using the helical diffraction theory. From a known structure as given by the chiral indices (u, v), its electron diffraction pattern can be calculated and understood. The reverse problem, i.e. assignment of the chiral indices from an electron diffraction pattern of a carbon nanotube, is approached from the relationship between the electron scattering intensity distribution and the chiral indices (u, v). We show that electron diffraction patterns can provide an accurate and unambiguous assignment of the chiral indices of carbon nanotubes. The chiral indices (u, v) can be read indiscriminately with a high accuracy from the intensity distribution on the principal layer lines in an electron diffraction pattern. The symmetry properties of electron diffraction from carbon nanotubes and the electron diffraction from deformed carbon nanotubes are also discussed in detail. It is shown that 2mm symmetry is always preserved for single-walled carbon nanotubes, but it can break down for multiwalled carbon nanotubes under some special circumstances

  8. Continuous high-yield production of vertically aligned carbon nanotubes on 2D and 3D substrates.

    Science.gov (United States)

    Guzmán de Villoria, Roberto; Hart, A John; Wardle, Brian L

    2011-06-28

    Vertically aligned carbon nanotubes (VACNTs) have certain advantages over bulk CNT powders and randomly oriented CNT mats for applications in flexible electronic devices, filtration membranes, biosensors and multifunctional aerospace materials. Here, a machine and a process to synthesize VACNTs in a continuous manner are presented showing uniform growth on 2D and 3D substrates, including alumina fibers, silicon wafer pieces, and stainless steel foils. Aligned multiwalled carbon nanotubes (MWNT) are synthesized at substrate feed rates of up to 6.8 cm/min, and the CNTs reach up to 60 μm in length depending on residence time in the reactor. In addition to the aligned morphology indicative of high yield growth, transmission electron microscopy and Raman spectroscopy reveal that the CNTs are of comparable quality to CNTs grown via a similar batch process. A significant reduction in time, reaction products, gases, and energy is demonstrated relative to batch processing, paving the way for industrial production of VACNTs.

  9. High Performance Flexible Pseudocapacitor based on Nano-architectured Spinel Nickel Cobaltite Anchored Multiwall Carbon Nanotubes

    International Nuclear Information System (INIS)

    Shakir, Imran

    2014-01-01

    Highlights: • Two-step fabrication method for nano-architectured spinel nickel cobaltite (NiCo 2 O 4 ) anchored MWCNTs composite. • High performance flexible energy-storage devices. • The NiCo 2 O 4 anchored MWCNTs Exhibits 2032 Fg −1 capacitance which is 1.62 times greater than pristine NiCo 2 O 4 at 1 Ag −1 . - Abstract: We demonstrate a facile two-step fabrication method for nano-architectured spinel nickel cobaltite (NiCo 2 O 4 ) anchored multiwall carbon nanotubes (MWCNTs) based electrodes for high performance flexible energy-storage devices. As electrode materials for flexible supercapacitors, the NiCo 2 O 4 anchored MWCNTs exhibits a high specific capacitance of 2032 Fg −1 , which is nearly 1.62 times greater than pristine NiCo 2 O 4 nanoflakes at 1 Ag −1 . The synthesized NiCo 2 O 4 anchored MWCNTs composite shows excellent rate performance (83.96% capacity retention at 30 Ag −1 ) and stability with coulombic efficiency over 96% after 5,000 cycles when being fully charged/discharged at 1 Ag −1 . Furthermore, NiCo 2 O 4 anchored MWCNTs achieve a maximum energy density of 48.32 Whkg −1 at a power density of 480 Wkg −1 which is 60% higher than pristine NiCo 2 O 4 electrode and significantly outperformed electrode materials based on NiCo 2 O 4 which are currently used in the state-of-the-art supercapacitors throughout the literature. This superior rate performance and high-capacity value offered by NiCo 2 O 4 anchored MWCNTs is mainly due to enhanced electronic and ionic conductivity, which provides a short diffusion path for ions and an easy access of electrolyte flow to nickel cobaltite redox centers besides the high conductivity of MWCNTs

  10. A Nacre-Like Carbon Nanotube Sheet for High Performance Li-Polysulfide Batteries with High Sulfur Loading.

    Science.gov (United States)

    Pan, Zheng-Ze; Lv, Wei; He, Yan-Bing; Zhao, Yan; Zhou, Guangmin; Dong, Liubing; Niu, Shuzhang; Zhang, Chen; Lyu, Ruiyang; Wang, Cong; Shi, Huifa; Zhang, Wenjie; Kang, Feiyu; Nishihara, Hirotomo; Yang, Quan-Hong

    2018-06-01

    Lithium-sulfur (Li-S) batteries are considered as one of the most promising energy storage systems for next-generation electric vehicles because of their high-energy density. However, the poor cyclic stability, especially at a high sulfur loading, is the major obstacles retarding their practical use. Inspired by the nacre structure of an abalone, a similar configuration consisting of layered carbon nanotube (CNT) matrix and compactly embedded sulfur is designed as the cathode for Li-S batteries, which are realized by a well-designed unidirectional freeze-drying approach. The compact and lamellar configuration with closely contacted neighboring CNT layers and the strong interaction between the highly conductive network and polysulfides have realized a high sulfur loading with significantly restrained polysulfide shuttling, resulting in a superior cyclic stability and an excellent rate performance for the produced Li-S batteries. Typically, with a sulfur loading of 5 mg cm -2 , the assembled batteries demonstrate discharge capacities of 1236 mAh g -1 at 0.1 C, 498 mAh g -1 at 2 C and moreover, when the sulfur loading is further increased to 10 mg cm -2 coupling with a carbon-coated separator, a superhigh areal capacity of 11.0 mAh cm -2 is achieved.

  11. 3D printing of highly elastic strain sensors using polyurethane/multiwall carbon nanotube composites

    Science.gov (United States)

    Christ, Josef F.; Hohimer, Cameron J.; Aliheidari, Nahal; Ameli, Amir; Mo, Changki; Pötschke, Petra

    2017-04-01

    As the desire for wearable electronics increases and the soft robotics industry advances, the need for novel sensing materials has also increased. Recently, there have been many attempts at producing novel materials, which exhibit piezoresistive behavior. However, one of the major shortcomings in strain sensing technologies is in the fabrication of such sensors. While there is significant research and literature covering the various methods for developing piezoresistive materials, fabricating complex sensor platforms is still a manufacturing challenge. Here, we report a facile method to fabricate multidirectional embedded strain sensors using additive manufacturing technology. Pure thermoplastic polyurethane (TPU) and TPU/multiwall carbon nanotubes (MWCNT) nanocomposites were 3D printed in tandem using a low-cost multi-material FDM printer to fabricate uniaxial and biaxial strain sensors with conductive paths embedded within the insulative TPU platform. The sensors were then subjected to a series of cyclic strain loads. The results revealed excellent piezoresistive responses of the sensors with cyclic repeatability in both the axial and transverse directions and in response to strains as high as 50%. Further, while strain-softening did occur in the embedded printed strain sensors, it was predictable and similar to the results found in the literature for bulk polymer nanocomposites. This works demonstrates the possibility of manufacturing embedded and multidirectional flexible strain sensors using an inexpensive and versatile method, with potential applications in soft robotics and flexible electronics and health monitoring.

  12. Hybrid metal grid-polymer-carbon nanotube electrodes for high luminance organic light emitting diodes

    International Nuclear Information System (INIS)

    Sam, F Laurent M; Dabera, G Dinesha M R; Lai, Khue T; Mills, Christopher A; Rozanski, Lynn J; Silva, S Ravi P

    2014-01-01

    Organic light emitting diodes (OLEDs) incorporating grid transparent conducting electrodes (TCEs) with wide grid line spacing suffer from an inability to transfer charge carriers across the gaps in the grids to promote light emission in these areas. High luminance OLEDs fabricated using a hybrid TCE composed of poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS PH1000) or regioregular poly(3-hexylthiophene)-wrapped semiconducting single-walled carbon nanotubes (rrP3HT-SWCNT) in combination with a nanometre thin gold grid are reported here. OLEDs fabricated using the hybrid gold grid/PH1000 TCE have a luminance of 18 000 cd m −2 at 9 V; the same as the reference indium tin oxide (ITO) OLED. The gold grid/rrP3HT-SWCNT OLEDs have a lower luminance of 8260 cd m −2 at 9 V, which is likely due to a rougher rrP3HT-SWCNT surface. These results demonstrate that the hybrid gold grid/PH1000 TCE is a promising replacement for ITO in future plastic electronics applications including OLEDs and organic photovoltaics. For applications where surface roughness is not critical, e.g. electrochromic devices or discharge of static electricity, the gold grid/rrP3HT-SWCNT hybrid TCE can be employed. (paper)

  13. High Electrocatalytic Activity of Vertically Aligned Single-Walled Carbon Nanotubes towards Sulfide Redox Shuttles.

    Science.gov (United States)

    Hao, Feng; Dong, Pei; Zhang, Jing; Zhang, Yongchang; Loya, Phillip E; Hauge, Robert H; Li, Jianbao; Lou, Jun; Lin, Hong

    2012-01-01

    Vertically aligned single-walled carbon nanotubes (VASWCNTs) have been successfully transferred onto transparent conducting oxide glass and implemented as efficient low-cost, platinum-free counter electrode in sulfide -mediated dye-sensitized solar cells (DSCs), featuring notably improved electrocatalytic activity toward thiolate/disulfide redox shuttle over conventional Pt counter electrodes. Impressively, device with VASWCNTs counter electrode demonstrates a high fill factor of 0.68 and power conversion efficiency up to 5.25%, which is significantly higher than 0.56 and 3.49% for that with a conventional Pt electrode. Moreover, VASWCNTs counter electrode produces a charge transfer resistance of only 21.22 Ω towards aqueous polysulfide electrolyte commonly applied in quantum dots-sensitized solar cells (QDSCs), which is several orders of magnitude lower than that of a typical Pt electrode. Therefore, VASWCNTs counter electrodes are believed to be a versatile candidate for further improvement of the power conversion efficiency of other iodine-free redox couple based DSCs and polysulfide electrolyte based QDSCs.

  14. Synthesis of multi-walled carbon nanotubes/{beta}-FeOOH nanocomposites with high adsorption capacity

    Energy Technology Data Exchange (ETDEWEB)

    Song Haojie, E-mail: shj6922@163.com [School of Materials Science and Engineering, Jiangsu University (China); Liu Lei [Pharmaceutic College of Henan University (China); Jia Xiaohua; Min Chunying [School of Materials Science and Engineering, Jiangsu University (China)

    2012-12-15

    A hybrid nanostructure of multi-walled carbon nanotubes (CNTs) and {beta}-ferric oxyhydroxide ({beta}-FeOOH) nanoparticles is synthesized by ultrasonic-assisted in situ hydrolysis of the precursor ferric chloride and CNTs. Characterization by X-ray diffraction, scanning electron microscopy , and transmission electron microscopy establishes the nanohybrid structure of the synthesized sample. The results revealed that the surface of CNTs was uniformly assembled by numerous {beta}-FeOOH nanoparticles and had an average diameter of 3 nm. The formation route of anchoring {beta}-FeOOH nanoparticles onto CNTs was proposed as the intercalation and adsorption of iron ions onto the wall of CNTs, followed by the nucleation and growth of {beta}-FeOOH nanoparticles. The values of remanent magnetization (M{sub r}) and coercivity (H{sub c}) of the as-synthesized CNTs/{beta}-FeOOH nanocomposites were 0.1131 emu g, and 490.824 Oe, respectively. Furthermore, CNTs/{beta}-FeOOH nanocomposites showed a very high adsorption capacity of Congo red and thus these nanocomposites can be used as good adsorbents and can be used for the removal of the dye of Congo red from the waste water system.

  15. High Thermoelectric Power Factor Organic Thin Films through Combination of Nanotube Multilayer Assembly and Electrochemical Polymerization.

    Science.gov (United States)

    Culebras, Mario; Cho, Chungyeon; Krecker, Michelle; Smith, Ryan; Song, Yixuan; Gómez, Clara M; Cantarero, Andrés; Grunlan, Jaime C

    2017-02-22

    In an effort to produce effective thermoelectric nanocomposites with multiwalled carbon nanotubes (MWCNT), layer-by-layer assembly was combined with electrochemical polymerization to create synergy that would produce a high power factor. Nanolayers of MWCNT stabilized with poly(diallyldimethylammonium chloride) or sodium deoxycholate were alternately deposited from water. Poly(3,4-ethylene dioxythiophene) [PEDOT] was then synthesized electrochemically by using this MWCNT-based multilayer thin film as the working electrode. Microscopic images show a homogeneous distribution of PEDOT around the MWCNT. The electrical resistance, conductivity (σ) and Seebeck coefficient (S) were measured before and after the PEDOT polymerization. A 30 bilayer MWCNT film (<1 μm thick) infused with PEDOT is shown to achieve a power factor (PF = S 2 σ) of 155 μW/m K 2 , which is the highest value ever reported for a completely organic MWCNT-based material and competitive with lead telluride at room temperature. The ability of this MWCNT-PEDOT film to generate power was demonstrated with a cylindrical thermoelectric generator that produced 5.5 μW with a 30 K temperature differential. This unique nanocomposite, prepared from water with relatively inexpensive ingredients, should open up new opportunities to recycle waste heat in portable/wearable electronics and other applications where low weight and mechanical flexibility are needed.

  16. Full Polymer Dielectric Elastomeric Actuators (DEA Functionalised with Carbon Nanotubes and High-K Ceramics

    Directory of Open Access Journals (Sweden)

    Tilo Köckritz

    2016-09-01

    Full Text Available Dielectric elastomer actuators (DEA are special devices which have a simple working and construction principle and outstanding actuation properties. The DEAs consist of a combination of different materials for the dielectric and electrode layers. The combination of these layers causes incompatibilities in their interconnections. Dramatic differences in the mechanical properties and bad adhesion of the layers are the principal causes for the reduction of the actuation displacement and strong reduction of lifetime. Common DEAs achieve actuation displacements of 2% and a durability of some million cycles. The following investigations represent a new approach to solving the problems of common systems. The investigated DEA consists of only one basic raw polymer, which was modified according to the required demands of each layer. The basic raw polymer was modified with single-walled carbon nanotubes or high-k ceramics, for example, lead magnesium niobate-lead titanate. The development of the full polymer DEA comprised the development of materials and technologies to realise a reproducible layer composition. It was proven that the full polymer actuator worked according to the theoretical rules. The investigated system achieved actuation displacements above 20% regarding thickness, outstanding interconnections at each layer without any failures, and durability above 3 million cycles without any indication of an impending malfunction.

  17. Effect of Modified and Nonmodified Carbon Nanotubes on the Rheological Behavior of High Density Polyethylene Nanocomposite

    Directory of Open Access Journals (Sweden)

    Adewunmi A. Ahmad

    2013-01-01

    Full Text Available This paper reports the results of studies on the rheological behavior of nanocomposites of high density polyethylene (HDPE with pristine multiwall carbon nanotubes (CNT as well as phenol and 1-octadecanol (C18 functionalized CNT at 1, 2, 3, 4, 5, and 7 wt% loading. The viscosity reduction at 1 wt% CNT follows the order, pristine CNT < phenol functionalized CNT < C18 functionalized CNT. As the filler loading increases from 1 to 2, 3, and 4 wt%, neat HDPE and filled HDPE systems show similar moduli and viscosity, particularly in the low frequency region. As the filler loading increases further to 5 and 7 wt%, the viscosity and moduli become greater than the neat HDPE. The storage modulus, tan, and the Cole-Cole plots show that CNT network formation occurs at higher CNT loading. The critical CNT loading or the rheological percolation threshold, where network formation occurs is found to be strongly dependant on the functionalization of CNT. For pristine CNT, the rheological percolation threshold is around 4 wt%, but for functionalized CNT it is around 7 wt%. The surface morphologies of CNT and functionalized CNT at 1 wt% loading showed good dispersion while at 7 wt% loading, dispersion was also achieved, but there are few regions with agglomeration of CNT.

  18. Study on the Highly Sensitive AChE Electrode Based on Multiwalled Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Shuping Zhang

    2014-01-01

    Full Text Available Using chitosan (CS as carrier, the method named layer-by-layer (LBL self-assembly modification to modify the glassy carbon electrode (GCE with multiwalled carbon nanotubes (MWNTs and acetylcholine esterase (AChE was proposed to prepare the acetylcholine esterase electrode with high sensitivity and stability. The modified electrode was used to detect pesticide of aldicarb, and the enzyme inhibition rate of the electrode showed good linearity with pesticide concentrations in the range of 10−10 g·L−1 to 10−3 g·L−1. The detection limit was 10−11 g·L−1. The modified electrode was also used to detect the actual sample, and the recovery rate range was from 97.72% to 107.15%, which could meet the rapid testing need of the aldicarb residue. After being stored in the phosphate buffer solution (PBS in 4°C for 30 days, the modified electrode showed good stability with the response current that was 80% of the original current.

  19. A display module implemented by the fast high-temperatue response of carbon nanotube thin yarns.

    Science.gov (United States)

    Wei, Yang; Liu, Peng; Jiang, Kaili; Fan, Shoushan

    2012-05-09

    Suspending superaligned multiwalled carbon nanotube (MWCNT) films were processed into CNT thin yarns, about 1 μm in diameter, by laser cutting and an ethanol atomization bath treatment. The fast high-temperature response under a vacuum was revealed by monitoring the incandescent light with a photo diode. The thin yarns can be electrically heated up to 2170 K in 0.79 mS, and the succeeding cool-down time is 0.36 mS. The fast response is attributed to the ultrasmall mass of the independent single yarn, large radiation coefficient, and improved thermal conductance through the two cool ends. The millisecond response time makes it possible to use the visible hot thin yarns as light-emitting elements of an incandescent display. A fully sealed display with 16 × 16 matrix was successfully fabricated using screen-printed thick electrodes and CNT thin yarns. It can display rolling characters with a low power consumption. More applications can be further developed based on the addressable CNT thermal arrays.

  20. A Microneedle Functionalized with Polyethyleneimine and Nanotubes for Highly Sensitive, Label-Free Quantification of DNA.

    Science.gov (United States)

    Saadat-Moghaddam, Darius; Kim, Jong-Hoon

    2017-08-16

    The accurate measure of DNA concentration is necessary for many DNA-based biological applications. However, the current methods are limited in terms of sensitivity, reproducibility, human error, and contamination. Here, we present a microneedle functionalized with polyethyleneimine (PEI) and single-walled carbon nanotubes (SWCNTs) for the highly sensitive quantification of DNA. The microneedle was fabricated using ultraviolet (UV) lithography and anisotropic etching, and then functionalized with PEI and SWCNTs through a dip coating process. The electrical characteristics of the microneedle change with the accumulation of DNA on the surface. Current-voltage measurements in deionized water were conducted to study these changes in the electrical properties of the sensor. The sensitivity test found the signal to be discernable from the noise level down to 100 attomolar (aM), demonstrating higher sensitivity than currently available UV fluorescence and UV absorbance based methods. A microneedle without any surface modification only had a 100 femtomolar (fM) sensitivity. All measurement results were consistent with fluorescence microscopy.

  1. Mechanical Properties and Durability of Ultra High Strength Concrete Incorporating Multi-Walled Carbon Nanotubes.

    Science.gov (United States)

    Lu, Liulei; Ouyang, Dong; Xu, Weiting

    2016-05-27

    In this work, the effect of the addition of multi-walled carbon nanotubes (MWCNTs) on the mechanical properties and durability of ultra high strength concrete (UHSC) is reported. First, the MWCNTs were dispersed by a nano sand-mill in the presence of a surfactant in water. The UHSC specimens were prepared with various amounts of MWCNTs, ranging from 0% to 0.15% by weight of cement (bwoc). Results indicated that use of an optimal percentage of MWCNTs (0.05% bwoc) caused a 4.63% increase in compressive strength and a 24.0% decrease in chloride diffusion coefficient of UHSC at 28 days curing. Moreover, the addition of MWCNTs also improved the flexural strength and deformation ability. Furthermore, a field-emission scanning electron microscopy (FE-SEM) was used to observe the dispersion of MWCNTs in the cement matrix and morphology of the hardened cement paste containing MWCNTs. FE-SEM observation revealed that MWCNTs were well dispersed in the matrix and no agglomerate was found and the reinforcing effect of MWCNTs on UHSC was thought to be pulling out and microcrack bridging of MWCNTs, which transferred the load in tension.

  2. Very high S-band microwave absorption of carbon nanotube buckypapers with Mn nanoparticle interlayers

    Science.gov (United States)

    Lu, Shaowei; Bai, Yaoyao; Wang, Jijie; Zhang, Lu; Tian, Caijiao; Ma, Keming; Wang, Xiaoqiang

    2018-03-01

    Flexible and high-performance electromagnetic absorbing materials of multi-walled carbon nanotube (MWCNT) buckypapers with Mn nanoparticles (NPSs) interlayer were fabricated via monodisperse solutions through layer by layer vacuum filtration method. The morphology and element composition of buckypapers were characterized by scanning electron microscopy, energy dispersive spectrometer, and X-ray diffraction. The formation of flexible MWCNT buckypapers with Mn NPS (0-30 wt. %) interlayer was attributed to nanostructure and morphology of the samples. When the blended Mn NPS content in buckypapers is 20 wt. %, there are evidently two larger absorption peaks (-13.2 dB at 3.41 GHz, -15.6 dB at 3.52 GHz) of the buckypaper with an absorbing thickness of 0.1 mm. The fundamental microwave absorption mechanism of the buckypapers is discussed. This work opens a new pathway towards tuning microwave absorbers performance and this method can be extended to exploit other excellent microwave absorbers with interlayer.

  3. Growth of vertically aligned arrays of carbon nanotubes for high field emission

    International Nuclear Information System (INIS)

    Kim, D.; Lim, S.H.; Guilley, A.J.; Cojocaru, C.S.; Bouree, J.E.; Vila, L.; Ryu, J.H.; Park, K.C.; Jang, J.

    2008-01-01

    Vertically aligned multi-walled carbon nanotubes have been grown on Ni-coated silicon substrates, by using either direct current diode or triode plasma-enhanced chemical vapor deposition at low temperature (around 620 deg. C). Acetylene gas has been used as the carbon source while ammonia and hydrogen have been used for etching. However densely packed (∼ 10 9 cm -2 ) CNTs were obtained when the pressure was ∼ 100 Pa. The alignment of nanotubes is a necessary, but not a sufficient condition in order to get an efficient electron emission: the growth of nanotubes should be controlled along regular arrays, in order to minimize the electrostatic interactions between them. So a three dimensional numerical simulation has been developed to calculate the local electric field in the vicinity of the tips for a finite square array of nanotubes and thus to calculate the maximum of the electron emission current density as a function of the spacing between nanotubes. Finally the triode plasma-enhanced process combined with pre-patterned catalyst films (using different lithography techniques) has been chosen in order to grow regular arrays of aligned CNTs with different pitches in the micrometer range. The comparison between the experimental and the simulation data permits to define the most efficient CNT-based electron field emitters

  4. Ni0 encapsulated in N-doped carbon nanotubes for catalytic reduction of highly toxic hexavalent chromium

    Science.gov (United States)

    Yao, Yunjin; Zhang, Jie; Chen, Hao; Yu, Maojing; Gao, Mengxue; Hu, Yi; Wang, Shaobin

    2018-05-01

    N-doped carbon nanotubes encapsulating Ni0 nanoparticles (Ni@N-C) were fabricated via thermal reduction of dicyandiamide and NiCl2·6H2O, and used to remove CrVI in polluted water. The resultant products present an excellent catalytic activity for CrVI reduction using formic acid under relatively mild conditions. The CrVI reduction efficiency of Ni@N-C was significantly affected by the preparation conditions including the mass of nickel salt and synthesis temperatures. The impacts of several reaction parameters, such as initial concentrations of CrVI and formic acid, solution pH and temperatures, as well as inorganic anions in solution on CrVI reduction efficiency were also evaluated in view of scalable industrial applications. Owing to the synergistic effects amongst tubes-coated Ni0, doped nitrogen, oxygen containing groups, and the configuration of carbon nanotubes, Ni@N-C catalysts exhibit excellent catalytic activity and recyclable capability for CrVI reduction. Carbon shell can efficiently protect inner Ni0 core and N species from corrosion and subsequent leaching, while Ni0 endows the Ni@N-C catalysts with ferromagnetism, so that the composites can be easily separated via a permanent magnet. This study opens up an avenue for design of N-doped carbon nanotubes encapsulating Ni0 nanoparticles with high CrVI removal efficiency and magnetic recyclability as low-cost catalysts for industrial applications.

  5. Enhanced performance in capacitive force sensors using carbon nanotube/polydimethylsiloxane nanocomposites with high dielectric properties

    Science.gov (United States)

    Jang, Hyeyoung; Yoon, Hyungsuk; Ko, Youngpyo; Choi, Jaeyoo; Lee, Sang-Soo; Jeon, Insu; Kim, Jong-Ho; Kim, Heesuk

    2016-03-01

    Force sensors have attracted tremendous attention owing to their applications in various fields such as touch screens, robots, smart scales, and wearable devices. The force sensors reported so far have been mainly focused on high sensitivity based on delicate microstructured materials, resulting in low reproducibility and high fabrication cost that are limitations for wide applications. As an alternative, we demonstrate a novel capacitive-type force sensor with enhanced performance owing to the increased dielectric properties of elastomers and simple sensor structure. We rationally design dielectric elastomers based on alkylamine modified-multi-walled carbon nanotube (MWCNT)/polydimethylsiloxane (PDMS) composites, which have a higher dielectric constant than pure PDMS. The alkylamine-MWCNTs show excellent dispersion in a PDMS matrix, thus leading to enhanced and reliable dielectric properties of the composites. A force sensor array fabricated with alkylamine-MWCNT/PDMS composites presents an enhanced response due to the higher dielectric constant of the composites than that of pure PDMS. This study is the first to report enhanced performance of capacitive force sensors by modulating the dielectric properties of elastomers. We believe that the disclosed strategy to improve the sensor performance by increasing the dielectric properties of elastomers has great potential in the development of capacitive force sensor arrays that respond to various input forces.Force sensors have attracted tremendous attention owing to their applications in various fields such as touch screens, robots, smart scales, and wearable devices. The force sensors reported so far have been mainly focused on high sensitivity based on delicate microstructured materials, resulting in low reproducibility and high fabrication cost that are limitations for wide applications. As an alternative, we demonstrate a novel capacitive-type force sensor with enhanced performance owing to the increased

  6. A high resolution electron microscopy investigation of curvature in carbon nanotubes

    Science.gov (United States)

    Weldon, D. N.; Blau, W. J.; Zandbergen, H. W.

    1995-07-01

    Evidence for heptagon inclusion in multi-walled carbon nanotubes was sought in arc-produced carbon deposits. Transmission electron microscopy revealed many curved nanotubes although their relative abundance was low. Close examination of the micrographs in the regions of expected heptagon inclusion shows that the curvature is accomplished by folding or fracture of the lattice planes. This observed phenomenon contradicts the theoretical modelling studies which predict stable structures with negative curvature accomplished by heptagon/pentagon pairs. A possible explanation for curvature in single-walled tubes is presented based on a molecular mechanics geometry optimisation study of spa inclusion in a graphite sheet.

  7. High conductivity carbon nanotube wires from radial densification and ionic doping

    Science.gov (United States)

    Alvarenga, Jack; Jarosz, Paul R.; Schauerman, Chris M.; Moses, Brian T.; Landi, Brian J.; Cress, Cory D.; Raffaelle, Ryne P.

    2010-11-01

    Application of drawing dies to radially densify sheets of carbon nanotubes (CNTs) into bulk wires has shown the ability to control electrical conductivity and wire density. Simultaneous use of KAuBr4 doping solution, during wire drawing, has led to an electrical conductivity in the CNT wire of 1.3×106 S/m. Temperature-dependent electrical measurements show that conduction is dominated by fluctuation-assisted tunneling, and introduction of KAuBr4 significantly reduces the tunneling barrier between individual nanotubes. Ultimately, the concomitant doping and densification process leads to closer packed CNTs and a reduced charge transfer barrier, resulting in enhanced bulk electrical conductivity.

  8. High performance natural rubber composites with a hierarchical reinforcement structure of carbon nanotube modified natural fibers

    International Nuclear Information System (INIS)

    Tzounis, Lazaros; Debnath, Subhas; Rooj, Sandip; Fischer, Dieter; Mäder, Edith; Das, Amit; Stamm, Manfred; Heinrich, Gert

    2014-01-01

    A simple and facile method for depositing multiwall carbon nanotubes (MWCNTs) onto the surface of naturally occurring short jute fibers (JFs) is reported. Hierarchical multi-scale structures were formed with CNT-networks uniformly distributed and fully covering the JFs (JF–CNT), as depicted by the scanning electron microscopy (SEM) micrographs. The impact of these hybrid fillers on the mechanical properties of a natural rubber (NR) matrix was systematically investigated. Pristine JFs were cut initially to an average length of 2.0 mm and exposed to an alkali treatment (a-JFs) to remove impurities existing in the raw jute. MWCNTs were treated under mild acidic conditions to generate carboxylic acid moieties. Afterward, MWCNTs were dispersed in an aqueous media and short a-JFs were allowed to react with them. Raman spectroscopy confirmed the chemical interaction between CNTs and JFs. The JF–CNT exposed quite hydrophobic behavior as revealed by the water contact angle measurements, improving the wettability of the non-polar NR. Consequently, the composite interfacial adhesion strength was significantly enhanced while a micro-scale “mechanical interlocking” mechanism was observed from the interphase-section transmission electron microscopy (TEM) images. SEM analysis of the composite fracture surfaces demonstrated the interfacial strength of NR/a-JF and NR/JF–CNT composites, at different fiber loadings. It can be presumed that the CNT-coating effectively compatibillized the composite structure acting as a macromolecular coupling agent. A detailed analysis of stress-strain and dynamic mechanical spectra confirmed the high mechanical performance of the hierarchical composites, consisting mainly of materials arising from natural resources. - Highlights: • Natural rubber (NR) composites reinforced with CNT-modified short jute fibers. • MWCNTs deposited to the surface of jute fibers via non-covalent interactions. • Hierarchical reinforcement structure with

  9. High-temperature hydrogenation of pure and silver-decorated titanate nanotubes to increase their solar absorbance for photocatalytic applications

    Energy Technology Data Exchange (ETDEWEB)

    Plodinec, Milivoj [Ruđer Bošković Institute, Bijenička 54, HR-1002 Zagreb (Croatia); Gajović, Andreja, E-mail: gajovic@irb.hr [Ruđer Bošković Institute, Bijenička 54, HR-1002 Zagreb (Croatia); Jakša, Gregor; Žagar, Kristina; Čeh, Miran [Institute Jožef Stefan, Jamova 39, 1000 Ljubljana (Slovenia)

    2014-04-05

    Graphical abstract: The aim of the work is to study how annealing in a reducing atmosphere of titanate nanotubes (TiNT) and Ag decorated titanate nanotubes (TiNT@Ag) influenced on their structure, morphology, phase transitions, UV–ViS-NIR absorbance and photocatalytic activity. An increase of photocatalytic activity after a heat treatment in a reducing atmosphere was observed in the TiNT and TiNT@Ag. We found that the hydrogenated TiNT@Ag samples (TiNT@Ag-HA) had a two-times higher photodegradation impact on the caffeine than the TiNT samples, which is a consequence of the increased absorption of visible light and the synergetic effects between the silver and the TiO{sub 2} nanoparticles that increase the efficiency of the formation of electron–hole pairs and the charge transfer to the surface of the nanoparticles. -- Highlights: • Titanate nanotubes with and without Ag nanoparticles were hydrogenated at 550 °C. • TiO{sub 2} nanostructures obtained by hydrogenation have core–shell structure. • Hydrogenated samples show absorption in the visible spectral region. • Hydrogenated Ag decorated sample show stronger absorption in visible than in UV. • Photocatalytic efficiency is improved by hydrogenation and by Ag nanoparticles. -- Abstract: Titanate nanotubes (TiNTs) and silver-decorated titanate nanotubes (TiNTs@Ag) were synthesized using the hydrothermal method. In the decorated nanotubes the silver particles were obtained by the photoreduction of AgNO{sub 3} under UV light. Pure and Ag-decorated nanotubes were high-temperature heat treated at 550 °C in a hydrogen atmosphere and the “core–shell”-structured TiO{sub 2} nanoparticles were formed. For the structural characterization of all the titanate nanostructures we used conventional and analytical transmission electron microscopy (TEM) techniques, X-ray diffraction (XRD) and Raman spectroscopy. The Ag-decorated titanate nanostructures were additionally studied by X-ray photo

  10. Electrochemical Tuning of High Energy Photon Branches of Double Wall Carbon Nanotubes

    Czech Academy of Sciences Publication Activity Database

    Kalbáč, Martin; Kavan, Ladislav; Zukalová, Markéta; Dunsch, L.

    2004-01-01

    Roč. 42, č. 14 (2004), s. 2915-2920 ISSN 0008-6223 R&D Projects: GA AV ČR IAA4040306 Institutional research plan: CEZ:AV0Z4040901 Keywords : carbon nanotubes * Raman spectroscopy * electrochemical properties Subject RIV: CG - Electrochemistry Impact factor: 3.331, year: 2004

  11. Carbon nanotubes as electromechanical resonators : Single-electron tunneling, nonlinearity, and high-bandwidth readout

    NARCIS (Netherlands)

    Meerwaldt, H.B.

    2013-01-01

    A carbon nanotube (CNT) is a remarkable material and can be thought of as a single-atom thick cylinder of carbon atoms capped of with a semisphere. This is called a single-walled CNT and, depending on how the cylinder is rolled up, CNTs are either semiconducting or metallic. A CNT is made into a

  12. High-conductivity polymer nanocomposites obtained by tailoring the characteristics of carbon nanotube fillers

    NARCIS (Netherlands)

    Grossiord, N.; Loos, J.; Laake, van L.C.; Maugey, M.; Zakri, C.; Koning, C.E.; Hart, A.J.

    2008-01-01

    We present a detailed study of the influence of carbon nanotube (CNT) characteristics on the electrical conductivity of polystyrene nanocomposites produced using a latex-based approach. We processed both industrially-produced multi-wall CNT (MWCNT) powders and MWCNTs from vertically-aligned films

  13. Optimization routes for high electrical conductivity of polypyrrole nanotubes prepared in presence of methyl orange

    Czech Academy of Sciences Publication Activity Database

    Kopecký, D.; Varga, M.; Prokeš, J.; Vrňata, M.; Trchová, Miroslava; Kopecká, J.; Václavík, M.

    2017-01-01

    Roč. 230, August (2017), s. 89-96 ISSN 0379-6779 R&D Projects: GA ČR(CZ) GA16-02787S; GA ČR(CZ) GA17-04109S Institutional support: RVO:61389013 Keywords : polypyrrole * electrical conductivity * nanotube Subject RIV: CD - Macromolecular Chemistry OBOR OECD: Polymer science Impact factor: 2.435, year: 2016

  14. Synthesis of multiwall carbon nanotube wrapped Co(OH){sub 2} flakes: A high-performance supercapacitor

    Energy Technology Data Exchange (ETDEWEB)

    Mondal, Chanchal [Department of Chemistry, Indian Institute of Technology, Kharagpur 721302 (India); Ghosh, Debasis [Materials Science Centre, Indian Institute of Technology, Kharagpur 721302 (India); Ganguly, Mainak; Sasmal, Anup Kumar; Roy, Anindita [Department of Chemistry, Indian Institute of Technology, Kharagpur 721302 (India); Pal, Tarasankar, E-mail: tpal@chem.iitkgp.ernet.in [Department of Chemistry, Indian Institute of Technology, Kharagpur 721302 (India)

    2015-12-30

    Graphical abstract: - Highlights: • Multiwalled carbon nanotube wrapped Co(OH){sub 2} nanoflakes has been fabricated. • It showed high supercapcitive performance with specific capacitance of 603 F/g. • The as-prepared composite material exhibited remarkable cycling stability. • It may be applied for the development of supercapacitor electrode material. - Abstract: The problem of poor electron conductivity is always associated with pseudocapacitive electrode material that deters full utilization of the active material. To have a viable solution to this problem, we report fabrication of a composite material bringing highly conductive carbon nanotube (CNT) wrapped pseudocapacitive with Co(OH){sub 2} nanoflakes. An in situ growth route evolves the supercapacitor via our laboratory developed modified hydrothermal reaction condition (MHT). An electrochemical investigation substantiates that the composite material electrode is highly active, which delivers a maximum specific capacitance of 603 F g{sup −1} (at 1 mV s{sup −1} scan rate), outstanding long-term cyclic stability with 96% retention at a constant current density of 1.5 A g{sup −1} after 1000 cycles of operation. Thus it offers almost an effortless approach to fabricate high-power and high-energy density supercapacitors. By virtue of having high-capacity of pseudocapacitive hydroxides and desirable conductivity of carbon-based materials, the as-synthesized material could be a promising candidate for the development of supercapacitor electrode material.

  15. Continuous carbon nanotube reinforced composites.

    Science.gov (United States)

    Ci, L; Suhr, J; Pushparaj, V; Zhang, X; Ajayan, P M

    2008-09-01

    Carbon nanotubes are considered short fibers, and polymer composites with nanotube fillers are always analogues of random, short fiber composites. The real structural carbon fiber composites, on the other hand, always contain carbon fiber reinforcements where fibers run continuously through the composite matrix. With the recent optimization in aligned nanotube growth, samples of nanotubes in macroscopic lengths have become available, and this allows the creation of composites that are similar to the continuous fiber composites with individual nanotubes running continuously through the composite body. This allows the proper utilization of the extreme high modulus and strength predicted for nanotubes in structural composites. Here, we fabricate such continuous nanotube polymer composites with continuous nanotube reinforcements and report that under compressive loadings, the nanotube composites can generate more than an order of magnitude improvement in the longitudinal modulus (up to 3,300%) as well as damping capability (up to 2,100%). It is also observed that composites with a random distribution of nanotubes of same length and similar filler fraction provide three times less effective reinforcement in composites.

  16. A low-frequency wave motion mechanism enables efficient energy transport in carbon nanotubes at high heat fluxes.

    Science.gov (United States)

    Zhang, Xiaoliang; Hu, Ming; Poulikakos, Dimos

    2012-07-11

    The great majority of investigations of thermal transport in carbon nanotubes (CNTs) in the open literature focus on low heat fluxes, that is, in the regime of validity of the Fourier heat conduction law. In this paper, by performing nonequilibrium molecular dynamics simulations we investigated thermal transport in a single-walled CNT bridging two Si slabs under constant high heat flux. An anomalous wave-like kinetic energy profile was observed, and a previously unexplored, wave-dominated energy transport mechanism is identified for high heat fluxes in CNTs, originated from excited low frequency transverse acoustic waves. The transported energy, in terms of a one-dimensional low frequency mechanical wave, is quantified as a function of the total heat flux applied and is compared to the energy transported by traditional Fourier heat conduction. The results show that the low frequency wave actually overtakes traditional Fourier heat conduction and efficiently transports the energy at high heat flux. Our findings reveal an important new mechanism for high heat flux energy transport in low-dimensional nanostructures, such as one-dimensional (1-D) nanotubes and nanowires, which could be very relevant to high heat flux dissipation such as in micro/nanoelectronics applications.

  17. A digital miniature x-ray tube with a high-density triode carbon nanotube field emitter

    International Nuclear Information System (INIS)

    Jeong, Jin-Woo; Kang, Jun-Tae; Choi, Sungyoul; Kim, Jae-Woo; Song, Yoon-Ho; Ahn, Seungjoon

    2013-01-01

    We have fabricated a digital miniature x-ray tube (6 mm in diameter and 32 mm in length) with a high-density triode carbon nanotube (CNT) field emitter for special x-ray applications. The triode CNT emitter was densely formed within a diameter of below 4 mm with the focusing-functional gate. The brazing process enables us to obtain and maintain a desired vacuum level for the reliable electron emission from the CNT emitters after the vacuum packaging. The miniature x-ray tube exhibited a stable and reliable operation over 250 h in a pulse mode at an anode voltage of above 25 kV.

  18. Driving High-Performance n- and p-type Organic Transistors with Carbon Nanotube/Conjugated Polymer Composite Electrodes Patterned Directly from Solution

    KAUST Repository

    Hellstrom, Sondra L.

    2010-07-12

    We report patterned deposition of carbon nanotube/conjugated polymer composites from solution with high nanotube densities and excellent feature resolution. Such composites are suited for use as electrodes in high-performance transistors of pentacene and C60, with bottom-contact mobilities of ?0.5 and ?1 cm2 V-1 s-1, respectively. This represents a clear step towards development of inexpensive, high-performance all-organic circuits. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. NiCoBP-doped carbon nanotube hybrid: A novel oxidase mimetic system for highly efficient electrochemical immunoassay

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Bing; He, Yu; Liu, Bingqian; Tang, Dianping, E-mail: dianping.tang@fzu.edu.cn

    2014-12-03

    Highlights: • We report a new oxidase mimetic system for highly efficient electrochemical immunoassay. • NiCoBP-doped carbon nanotube hybrids were used as the nanocatalysts. • NiCoBP-doped carbon nanotube hybrids were used as the mimic oxidase. - Abstract: NiCoBP-doped multi-walled carbon nanotube (NiCoBP–MWCNT) was first synthesized by using induced electroless-plating method and functionalized with the biomolecules for highly efficient electrochemical immunoassay of prostate-specific antigen (PSA, used as a model analyte). We discovered that the as-synthesized NiCoBP–MWCNT had the ability to catalyze the glucose oxidization with a stable and well-defined redox peak. The catalytic current increased with the increment of the immobilized NiCoBP–MWCNT on the electrode. Transmission electron microscope (TEM) and energy dispersive X-ray spectrometry (EDX) were employed to characterize the as-prepared NiCoBP–MWCNT. Using the NiCoBP–MWCNT-conjugated anti-PSA antibody as the signal-transduction tag, a new enzyme-free electrochemical immunoassay protocol could be designed for the detection of target PSA on the capture antibody-functionalized immunosensing interface. Experimental results revealed that the designed immunoassay system could exhibit good electrochemical responses toward target PSA, and allowed the detection of PSA at a concentration as low as 0.035 ng mL{sup −1}. More importantly, the NiCoBP-MWCNT-based oxidase mimetic system could be further extended for the monitoring of other low-abundance proteins or disease-related biomarkers by tuning the target antibody.

  20. High performance all-carbon composite transparent electrodes containing uniform carbon nanotube networks

    Energy Technology Data Exchange (ETDEWEB)

    Yun, Hyung Duk; Kwak, Jinsung; Kim, Se-Yang [School of Materials Science and Engineering & Low-Dimensional Carbon Materials Center, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919 (Korea, Republic of); Seo, Han; Bang, In Cheol; Kim, Sung Youb [School of Mechanical and Nuclear Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919 (Korea, Republic of); Kang, Seoktae [Department of Civil and Environmental Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141 (Korea, Republic of); Kwon, Soon-Yong, E-mail: sykwon@unist.ac.kr [School of Materials Science and Engineering & Low-Dimensional Carbon Materials Center, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919 (Korea, Republic of); School of Mechanical and Nuclear Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919 (Korea, Republic of)

    2016-08-05

    Indium tin oxide-free, flexible transparent electrodes (TEs) are crucial for the future commercialization of flexible and wearable electronics. While carbon-based TEs containing carbon nanotube (CNT) networks show promise, they usually exhibit poor dispersion properties, limiting their performance and practicality. In this study, we report a highly efficient and bending durable all-carbon composite TE (ac-TE) that employs uniform CNT networks on a monolayer graphene/polyethylene terephthalate (PET) substrate via a simple air spray deposition method. The air-sprayed CNT/graphene assembly was free-standing on solution, making a polymer-free transfer of carbon composites to target substrates possible. The excellent performance of the ac-TEs was attributed to the uniformly networked CNTs on the polycrystalline graphene with a well-controlled density, effectively bridging the line defects and filling the tears/voids or folds necessarily existing in the as-processed graphene. The sheet resistance of the ac-TEs was increased only 6% from its original value at a bending radius of 2.7 mm, while that of the pristine graphene/PET assembly increased 237%. Mechanical bending of the ac-TEs worsened the electrical performance by only ∼1.7% after 2000 bending cycles at a bending radius of 2.5 mm. Degradation of the performance by the bending was the result of line defects formation in the graphene, demonstrating the potential of the uniform CNT networks to achieve more efficient and flexible carbon-based TEs. Furthermore, the chemically-doped ac-TEs showed commercially suitable electronic and optical properties with much enhanced thermal stability, closer to practical TEs in flexible devices. - Highlights: • Highly efficient and bending durable all-carbon composite transparent electrodes (TEs) are designed. • The performance was strongly dependent on morphology of CNT networks on graphene. • The mechanism relies on the defect reductions in graphene by uniform CNT coating

  1. Non-Planar Nanotube and Wavy Architecture Based Ultra-High Performance Field Effect Transistors

    KAUST Repository

    Hanna, Amir

    2016-11-01

    This dissertation presents a unique concept for a device architecture named the nanotube (NT) architecture, which is capable of higher drive current compared to the Gate-All-Around Nanowire architecture when applied to heterostructure Tunnel Field Effect Transistors. Through the use of inner/outer core-shell gates, heterostructure NT TFET leverages physically larger tunneling area thus achieving higher driver current (ION) and saving real estates by eliminating arraying requirement. We discuss the physics of p-type (Silicon/Indium Arsenide) and n-type (Silicon/Germanium hetero-structure) based TFETs. Numerical TCAD simulations have shown that NT TFETs have 5x and 1.6 x higher normalized ION when compared to GAA NW TFET for p and n-type TFETs, respectively. This is due to the availability of larger tunneling junction cross sectional area, and lower Shockley-Reed-Hall recombination, while achieving sub 60 mV/dec performance for more than 5 orders of magnitude of drain current, thus enabling scaling down of Vdd to 0.5 V. This dissertation also introduces a novel thin-film-transistors architecture that is named the Wavy Channel (WC) architecture, which allows for extending device width by integrating vertical fin-like substrate corrugations giving rise to up to 50% larger device width, without occupying extra chip area. The novel architecture shows 2x higher output drive current per unit chip area when compared to conventional planar architecture. The current increase is attributed to both the extra device width and 50% enhancement in field effect mobility due to electrostatic gating effects. Digital circuits are fabricated to demonstrate the potential of integrating WC TFT based circuits. WC inverters have shown 2× the peak-to-peak output voltage for the same input, and ~2× the operation frequency of the planar inverters for the same peak-to-peak output voltage. WC NAND circuits have shown 2× higher peak-to-peak output voltage, and 3× lower high-to-low propagation

  2. High performance all-carbon composite transparent electrodes containing uniform carbon nanotube networks

    International Nuclear Information System (INIS)

    Yun, Hyung Duk; Kwak, Jinsung; Kim, Se-Yang; Seo, Han; Bang, In Cheol; Kim, Sung Youb; Kang, Seoktae; Kwon, Soon-Yong

    2016-01-01

    Indium tin oxide-free, flexible transparent electrodes (TEs) are crucial for the future commercialization of flexible and wearable electronics. While carbon-based TEs containing carbon nanotube (CNT) networks show promise, they usually exhibit poor dispersion properties, limiting their performance and practicality. In this study, we report a highly efficient and bending durable all-carbon composite TE (ac-TE) that employs uniform CNT networks on a monolayer graphene/polyethylene terephthalate (PET) substrate via a simple air spray deposition method. The air-sprayed CNT/graphene assembly was free-standing on solution, making a polymer-free transfer of carbon composites to target substrates possible. The excellent performance of the ac-TEs was attributed to the uniformly networked CNTs on the polycrystalline graphene with a well-controlled density, effectively bridging the line defects and filling the tears/voids or folds necessarily existing in the as-processed graphene. The sheet resistance of the ac-TEs was increased only 6% from its original value at a bending radius of 2.7 mm, while that of the pristine graphene/PET assembly increased 237%. Mechanical bending of the ac-TEs worsened the electrical performance by only ∼1.7% after 2000 bending cycles at a bending radius of 2.5 mm. Degradation of the performance by the bending was the result of line defects formation in the graphene, demonstrating the potential of the uniform CNT networks to achieve more efficient and flexible carbon-based TEs. Furthermore, the chemically-doped ac-TEs showed commercially suitable electronic and optical properties with much enhanced thermal stability, closer to practical TEs in flexible devices. - Highlights: • Highly efficient and bending durable all-carbon composite transparent electrodes (TEs) are designed. • The performance was strongly dependent on morphology of CNT networks on graphene. • The mechanism relies on the defect reductions in graphene by uniform CNT coating

  3. Unusually high dispersion of nitrogen-doped carbon nanotubes in DNA solution.

    Science.gov (United States)

    Kim, Jin Hee; Kataoka, Masakazu; Fujisawa, Kazunori; Tojo, Tomohiro; Muramatsu, Hiroyuki; Vega-Díaz, Sofía M; Tristán-López, F; Hayashi, Takuya; Kim, Yoong Ahm; Endo, Morinobu; Terrones, Mauricio; Dresselhaus, Mildred S

    2011-12-08

    The dispersibility in a DNA solution of bundled multiwalled carbon nanotubes (MWCNTs), having different chemical functional groups on the CNT sidewall, was investigated by optical spectroscopy. We observed that the dispersibility of nitrogen (N)-doped MWCNTs was significantly higher than that of pure MWCNTs and MWCNTs synthesized in the presence of ethanol. This result is supported by the larger amount of adsorbed DNA on N-doped MWCNTs, as well as by the higher binding energy established between nucleobases and the N-doped CNTs. Pure MWCNTs are dispersed in DNA solution via van der Waals and hydrophobic interactions; in contrast, the nitrogenated sites within N-doped MWCNTs provided additional sites for interactions that are important to disperse nanotubes in DNA solutions. © 2011 American Chemical Society

  4. Integrated high-efficiency Pt/carbon nanotube arrays for PEM fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Weimin; Minett, Andrew I.; Zhao, Jie; Razal, Joselito M.; Wallace, Gordon G.; Romeo, Tony; Chen, Jun [Intelligent Polymer Research Institute, AIIM Facility, Innovation Campus, University of Wollongong, NSW 2522 (Australia); Gao, Mei [Division of Materials Science and Engineering, CSIRO, Bayview Ave, Clayton, VIC 3168 (Australia)

    2011-07-15

    A facile strategy to deposit Pt nanoparticles with various metal-loading densities on vertically aligned carbon nanotube (ACNT) arrays as electrocatalysts for proton exchange membrane (PEM) fuel cells is described. The deposition is achieved by electrostatic adsorption of the Pt precursor on the positively charged polyelectrolyte functionalized ACNT arrays and subsequent reduction by L-ascorbic acid. The application of the aligned electrocatalysts in fuel cells is realized by transferring from a quartz substrate to nafion membrane using a hot-press procedure to fabricate the membrane electrode assembly (MEA). It is shown that the MEA with vertically aligned structured electrocatalysts provides better Pt utilization than that with Pt on conventional carbon nanotubes or carbon black, resulting in higher fuel cell performance. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  5. Highly stretchable carbon nanotube transistors enabled by buckled ion gel gate dielectrics

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Meng-Yin; Chang, Tzu-Hsuan; Ma, Zhenqiang [Department of Electrical and Computer Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); Zhao, Juan [School of Optoelectronic Information, University of Electronic Science and Technology of China, Chengdu 610054 (China); Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); Xu, Feng; Jacobberger, Robert M.; Arnold, Michael S., E-mail: michael.arnold@wisc.edu [Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States)

    2015-08-03

    Deformable field-effect transistors (FETs) are expected to facilitate new technologies like stretchable displays, conformal devices, and electronic skins. We previously demonstrated stretchable FETs based on buckled thin films of polyfluorene-wrapped semiconducting single-walled carbon nanotubes as the channel, buckled metal films as electrodes, and unbuckled flexible ion gel films as the dielectric. The FETs were stretchable up to 50% without appreciable degradation in performance before failure of the ion gel film. Here, we show that by buckling the ion gel, the integrity and performance of the nanotube FETs are extended to nearly 90% elongation, limited by the stretchability of the elastomer substrate. The FETs maintain an on/off ratio of >10{sup 4} and a field-effect mobility of 5 cm{sup 2} V{sup −1} s{sup −1} under elongation and demonstrate invariant performance over 1000 stretching cycles.

  6. Highly stretchable carbon nanotube transistors enabled by buckled ion gel gate dielectrics

    International Nuclear Information System (INIS)

    Wu, Meng-Yin; Chang, Tzu-Hsuan; Ma, Zhenqiang; Zhao, Juan; Xu, Feng; Jacobberger, Robert M.; Arnold, Michael S.

    2015-01-01

    Deformable field-effect transistors (FETs) are expected to facilitate new technologies like stretchable displays, conformal devices, and electronic skins. We previously demonstrated stretchable FETs based on buckled thin films of polyfluorene-wrapped semiconducting single-walled carbon nanotubes as the channel, buckled metal films as electrodes, and unbuckled flexible ion gel films as the dielectric. The FETs were stretchable up to 50% without appreciable degradation in performance before failure of the ion gel film. Here, we show that by buckling the ion gel, the integrity and performance of the nanotube FETs are extended to nearly 90% elongation, limited by the stretchability of the elastomer substrate. The FETs maintain an on/off ratio of >10 4 and a field-effect mobility of 5 cm 2 V −1 s −1 under elongation and demonstrate invariant performance over 1000 stretching cycles

  7. PT AND PT/NI "NEEDLE" ELETROCATALYSTS ON CARBON NANOTUBES WITH HIGH ACTIVITY FOR THE ORR

    Energy Technology Data Exchange (ETDEWEB)

    Colon-Mercado, H.

    2011-11-10

    Platinum and platinum/nickel alloy electrocatalysts supported on graphitized (gCNT) or nitrogen doped carbon nanotubes (nCNT) are prepared and characterized. Pt deposition onto carbon nanotubes results in Pt 'needle' formations that are 3.5 nm in diameter and {approx}100 nm in length. Subsequent Ni deposition and heat treatment results in PtNi 'needles' with an increased diameter. All Pt and Pt/Ni materials were tested as electrocatalysts for the oxygen reduction reaction (ORR). The Pt and Pt/Ni catalysts showed excellent performance for the ORR, with the heat treated PtNi/gCNT (1.06 mA/cm{sup 2}) and PtNi/nCNT (0.664 mA/cm{sup 2}) showing the highest activity.

  8. Realizing one-dimensional quantum and high-frequency transport features in aligned single-walled carbon nanotube ropes

    Energy Technology Data Exchange (ETDEWEB)

    Ncube, Siphephile; Chimowa, George; Chiguvare, Zivayi; Bhattacharyya, Somnath, E-mail: Somnath.Bhattacharyya@wits.ac.za [Nano-Scale Transport Physics Laboratory, School of Physics and DST/NRF Centre of Excellence in Strong Materials, University of the Witwatersrand, Private Bag 3, WITS 2050, Johannesburg (South Africa)

    2014-07-14

    The superiority of the electronic transport properties of single-walled carbon nanotube (SWNT) ropes over SWNT mats is verified from low temperature and frequency-dependent transport. The overall change of resistance versus in nanotube mats shows that 3D variable range hopping is the dominant conduction mechanism within the 2–300 K range. The magneto-resistance (MR) is found to be predominantly negative with a parabolic nature, which can also be described by the hopping model. Although the positive upturn of the MR at low temperatures establishes the contribution from quantum interference, the inherent quantum transport in individual tubes is suppressed at elevated temperatures. Therefore, to minimize multi-channel effects from inter-tube interactions and other defects, two-terminal devices were fabricated from aligned SWNT (extracted from a mat) for low temperature transport as well as high-frequency measurements. In contrast to the mat, the aligned ropes exhibit step-like features in the differential conductance within the 80–300 K temperature range. The effects of plasmon propagation, unique to one dimension, were identified in electronic transport as a non-universal power-law dependence of the differential conductance on temperature and source-drain voltage. The complex impedance showed high power transmission capabilities up to 65 GHz as well as oscillations in the frequency range up to 30 GHz. The measurements suggest that aligned SWNT ropes have a realistic potential for high-speed device applications.

  9. Realizing one-dimensional quantum and high-frequency transport features in aligned single-walled carbon nanotube ropes

    Science.gov (United States)

    Ncube, Siphephile; Chimowa, George; Chiguvare, Zivayi; Bhattacharyya, Somnath

    2014-07-01

    The superiority of the electronic transport properties of single-walled carbon nanotube (SWNT) ropes over SWNT mats is verified from low temperature and frequency-dependent transport. The overall change of resistance versus in nanotube mats shows that 3D variable range hopping is the dominant conduction mechanism within the 2-300 K range. The magneto-resistance (MR) is found to be predominantly negative with a parabolic nature, which can also be described by the hopping model. Although the positive upturn of the MR at low temperatures establishes the contribution from quantum interference, the inherent quantum transport in individual tubes is suppressed at elevated temperatures. Therefore, to minimize multi-channel effects from inter-tube interactions and other defects, two-terminal devices were fabricated from aligned SWNT (extracted from a mat) for low temperature transport as well as high-frequency measurements. In contrast to the mat, the aligned ropes exhibit step-like features in the differential conductance within the 80-300 K temperature range. The effects of plasmon propagation, unique to one dimension, were identified in electronic transport as a non-universal power-law dependence of the differential conductance on temperature and source-drain voltage. The complex impedance showed high power transmission capabilities up to 65 GHz as well as oscillations in the frequency range up to 30 GHz. The measurements suggest that aligned SWNT ropes have a realistic potential for high-speed device applications.

  10. Nafion titania nanotubes nanocomposite electrolytes for high-temperature direct methanol fuel cells

    CSIR Research Space (South Africa)

    Cele, NP

    2012-01-01

    Full Text Available electrolytes membranes. This promotes to study the Nafion/TNTs nanocomposite membranes behaviour with the aim to improve Nafion properties such as fuel permeability and thermal and mechanical stability. Nafion, whose primary structure consists of acid... membrane properties, further investigations were carried out. In this study, the effects of TiO2 nanotubes on Nafion properties such as water uptake, thermal stability, methanol (MeOH) permeability, and ion conductivity were investigated...

  11. High-performance silicon nanotube tunneling FET for ultralow-power logic applications

    KAUST Repository

    Fahad, Hossain M.; Hussain, Muhammad Mustafa

    2013-01-01

    To increase typically low output drive currents from tunnel field-effect transistors (FETs), we show a silicon vertical nanotube (NT) architecture-based FET's effectiveness. Using core (inner) and shell (outer) gate stacks, the silicon NT tunneling FET shows a sub-60 mV/dec subthreshold slope, ultralow off -state leakage current, higher drive current compared with gate-all-around nanowire silicon tunnel FETs. © 1963-2012 IEEE.

  12. High-performance silicon nanotube tunneling FET for ultralow-power logic applications

    KAUST Repository

    Fahad, Hossain M.

    2013-03-01

    To increase typically low output drive currents from tunnel field-effect transistors (FETs), we show a silicon vertical nanotube (NT) architecture-based FET\\'s effectiveness. Using core (inner) and shell (outer) gate stacks, the silicon NT tunneling FET shows a sub-60 mV/dec subthreshold slope, ultralow off -state leakage current, higher drive current compared with gate-all-around nanowire silicon tunnel FETs. © 1963-2012 IEEE.

  13. Transparent conducting oxide nanotubes

    Science.gov (United States)

    Alivov, Yahya; Singh, Vivek; Ding, Yuchen; Nagpal, Prashant

    2014-09-01

    Thin film or porous membranes made of hollow, transparent, conducting oxide (TCO) nanotubes, with high chemical stability, functionalized surfaces and large surface areas, can provide an excellent platform for a wide variety of nanostructured photovoltaic, photodetector, photoelectrochemical and photocatalytic devices. While large-bandgap oxide semiconductors offer transparency for incident light (below their nominal bandgap), their low carrier concentration and poor conductivity makes them unsuitable for charge conduction. Moreover, materials with high conductivity have nominally low bandgaps and hence poor light transmittance. Here, we demonstrate thin films and membranes made from TiO2 nanotubes heavily-doped with shallow Niobium (Nb) donors (up to 10%, without phase segregation), using a modified electrochemical anodization process, to fabricate transparent conducting hollow nanotubes. Temperature dependent current-voltage characteristics revealed that TiO2 TCO nanotubes, doped with 10% Nb, show metal-like behavior with resistivity decreasing from 6.5 × 10-4 Ωcm at T = 300 K (compared to 6.5 × 10-1 Ωcm for nominally undoped nanotubes) to 2.2 × 10-4 Ωcm at T = 20 K. Optical properties, studied by reflectance measurements, showed light transmittance up to 90%, within wavelength range 400 nm-1000 nm. Nb doping also improves the field emission properties of TCO nanotubes demonstrating an order of magnitude increase in field-emitter current, compared to undoped samples.

  14. Preparation high photocatalytic activity of CdS/halloysite nanotubes (HNTs) nanocomposites with hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Xing Weinan [School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013 (China); Ni Liang, E-mail: xingweinan3@126.com [School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013 (China); Huo Pengwei; Lu Ziyang; Liu Xinlin; Luo Yingying; Yan Yongsheng [School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013 (China)

    2012-10-15

    Highlights: Black-Right-Pointing-Pointer CdS/halloysite nanotubes (HNTs) were synthesized by hydrothermal method. Black-Right-Pointing-Pointer The CdS/HNTs had better photocatalytic activity for degradation of tetracycline. Black-Right-Pointing-Pointer The presence of halloysite nanotubes both improved its photocatalytic activity and stability. - Abstract: A novel nanocatalyst CdS/halloysite nanotubes (HNTs) was synthesized by hydrothermal method with direct growth of CdS nanoparticles on the surface of HNTs. The as-prepared photocatalysts had been characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), UV-vis diffuse reflectance spectra (UV-vis DRS), Fourier transform infrared (FT-IR) and the thermo gravimetric analysis (TGA). The photocatalytic activity of the sample was evaluated by the degradation of tetracycline (TC) under visible light irradiation. Benefit from the excellent properties of CdS and HNTs, the photocatalyst exhibited good photocatalytic activity and stability. In order to find out the optimum synthesis condition to obtain the best photocatalytic activity, a series of experiments were performed with different CdS loading capacity, different sources of sulfide and different hydrothermal temperatures, etc. The best photodegradation rate could reach 93% in 60 min under visible light irradiation. Therefore, the combination of CdS nanoparticles with HNTs endowed this material with a potential use in environmental treatments in industries.

  15. Preparation high photocatalytic activity of CdS/halloysite nanotubes (HNTs) nanocomposites with hydrothermal method

    International Nuclear Information System (INIS)

    Xing Weinan; Ni Liang; Huo Pengwei; Lu Ziyang; Liu Xinlin; Luo Yingying; Yan Yongsheng

    2012-01-01

    Highlights: ► CdS/halloysite nanotubes (HNTs) were synthesized by hydrothermal method. ► The CdS/HNTs had better photocatalytic activity for degradation of tetracycline. ► The presence of halloysite nanotubes both improved its photocatalytic activity and stability. - Abstract: A novel nanocatalyst CdS/halloysite nanotubes (HNTs) was synthesized by hydrothermal method with direct growth of CdS nanoparticles on the surface of HNTs. The as-prepared photocatalysts had been characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), UV–vis diffuse reflectance spectra (UV–vis DRS), Fourier transform infrared (FT-IR) and the thermo gravimetric analysis (TGA). The photocatalytic activity of the sample was evaluated by the degradation of tetracycline (TC) under visible light irradiation. Benefit from the excellent properties of CdS and HNTs, the photocatalyst exhibited good photocatalytic activity and stability. In order to find out the optimum synthesis condition to obtain the best photocatalytic activity, a series of experiments were performed with different CdS loading capacity, different sources of sulfide and different hydrothermal temperatures, etc. The best photodegradation rate could reach 93% in 60 min under visible light irradiation. Therefore, the combination of CdS nanoparticles with HNTs endowed this material with a potential use in environmental treatments in industries.

  16. Mechanical properties of carbon nanotubes

    Science.gov (United States)

    Salvetat, J.-P.; Bonard, J.-M.; Thomson, N. H.; Kulik, A. J.; Forró, L.; Benoit, W.; Zuppiroli, L.

    A variety of outstanding experimental results on the elucidation of the elastic properties of carbon nanotubes are fast appearing. These are based mainly on the techniques of high-resolution transmission electron microscopy (HRTEM) and atomic force microscopy (AFM) to determine the Young's moduli of single-wall nanotube bundles and multi-walled nanotubes, prepared by a number of methods. These results are confirming the theoretical predictions that carbon nanotubes have high strength plus extraordinary flexibility and resilience. As well as summarising the most notable achievements of theory and experiment in the last few years, this paper explains the properties of nanotubes in the wider context of materials science and highlights the contribution of our research group in this rapidly expanding field. A deeper understanding of the relationship between the structural order of the nanotubes and their mechanical properties will be necessary for the development of carbon-nanotube-based composites. Our research to date illustrates a qualitative relationship between the Young's modulus of a nanotube and the amount of disorder in the atomic structure of the walls. Other exciting results indicate that composites will benefit from the exceptional mechanical properties of carbon nanotubes, but that the major outstanding problem of load transfer efficiency must be overcome before suitable engineering materials can be produced.

  17. Sn doped TiO{sub 2} nanotube with oxygen vacancy for highly efficient visible light photocatalysis

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jinliang; Xu, Xingtao [Engineering Research Center for Nanophotonics & Advanced Instrument, Ministry of Education, Shanghai Key Laboratory of Magnetic Resonance, School of Physics and Materials Science, Department of Physics, East China Normal University, Shanghai 200062 (China); Liu, Xinjuan [Institute of Coordination Bond Metrology and Engineering, College of Materials Science and Engineering, China Jiliang University, Hangzhou 310018 (China); Yu, Caiyan; Yan, Dong; Sun, Zhuo [Engineering Research Center for Nanophotonics & Advanced Instrument, Ministry of Education, Shanghai Key Laboratory of Magnetic Resonance, School of Physics and Materials Science, Department of Physics, East China Normal University, Shanghai 200062 (China); Pan, Likun, E-mail: lkpan@phy.ecnu.edu.cn [Engineering Research Center for Nanophotonics & Advanced Instrument, Ministry of Education, Shanghai Key Laboratory of Magnetic Resonance, School of Physics and Materials Science, Department of Physics, East China Normal University, Shanghai 200062 (China)

    2016-09-15

    Sn doped TiO{sub 2} nanotube with oxygen vacancy (V{sub o}-Sn−TiO{sub 2}) was successfully synthesized via a facile hydrothermal process and subsequent annealing in nitrogen atmosphere. The morphology, structure and photocatalytic performance of V{sub o}-Sn−TiO{sub 2} in the degradation of nitrobenzene were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, UV–vis absorption spectroscopy, nitrogen adsorption-desorption and electrochemical impedance spectra, respectively. The inner diameter, outer diameter and specific surface area of V{sub o}-Sn−TiO{sub 2} are about 5 nm, 15 nm and 235.54 m{sup 2} g{sup −1}, respectively. The experimental results show that the V{sub o}-Sn−TiO{sub 2} exhibits excellent photocatalytic performance with a maximum degradation rate of 92% in 300 min for nitrobenzene and 94% in 100 min for Rhodamine B and corresponding mineralization rates of 68% and 70% under visible light irradiation. The improved photocatalytic performance is ascribed to the enhanced light absorption and specific surface area as well as the reduced electron-hole pair recombination with the presence of oxygen vacancy and Sn doping in the TiO{sub 2} nanotube. - Highlights: • Photocatalysis is an environmental-friendly technology for nitrobenzene removal. • Sn doped TiO{sub 2} nanotube with oxygen vacancy is fabricated for the first time. • It exhibits excellent photocatalytic performance in degradation of nitrobenzene. • A high degradation rate of 92% is achieved under visible light irradiation.

  18. High-resolution 13C nuclear magnetic resonance evidence of phase transition of Rb,Cs-intercalated single-walled nanotubes

    KAUST Repository

    Bouhrara, M.

    2011-09-06

    We present 13 C high-resolution magic-angle-turning (MAT) and magic angle spinning nuclear magnetic resonance data of Cs and Rb intercalated single walled carbon nanotubes. We find two distinct phases at different intercalation levels. A simple charge transfer is applicable at low intercalation level. The new phase at high intercalation level is accompanied by a hybridization of alkali (s) orbitals with the carbon (sp2) orbitals of the single walled nanotubes, which indicate bundle surface sites is the most probable alkali site.

  19. Highly efficient biosensors by using well-ordered ZnO/ZnS core/shell nanotube arrays

    Science.gov (United States)

    Tarish, Samar; Xu, Yang; Wang, Zhijie; Mate, Faten; Al-Haddad, Ahmed; Wang, Wenxin; Lei, Yong

    2017-10-01

    We have studied the fabrication of highly efficient glucose sensors using well-ordered heterogeneous ZnO/ZnS core/shell nanotube arrays (CSNAs). The modified electrodes exhibit a superior electrochemical response towards ferrocyanide/ferricyanide and in glucose sensing. Further, the fabricated glucose biosensor exhibited good performance over an acceptable linear range from 2.39 × 10-5 to 2.66 × 10-4 mM, with a sensitivity of 188.34 mA mM-1 cm-2, which is higher than that of the ZnO nanotube array counterpart. A low limit of detection was realized (24 μM), which is good compared with electrodes based on conventional structures. In addition, the enhanced direct electrochemistry of glucose oxidase indicates the fast electron transfer of ZnO/ZnS CSNA electrodes, with a heterogeneous electron transfer rate constant (K s) of 1.69 s-1. The fast electron transfer is attributed to the high conductivity of the modified electrodes. The presented ZnS shell can facilitate the construction of future sensors and enhance the ZnO surface in a biological environment.

  20. Study of the highly ordered TiO2 nanotubes physical properties prepared with two-step anodization

    Science.gov (United States)

    Pishkar, Negin; Ghoranneviss, Mahmood; Ghorannevis, Zohreh; Akbari, Hossein

    2018-06-01

    Highly ordered hexagonal closely packed titanium dioxide nanotubes (TiO2 NTs) were successfully grown by a two-step anodization process. The TiO2 NTs were synthesized by electrochemical anodization of titanium foils in an ethylene glycol based electrolyte solution containing 0.3 wt% NH4F and 2 vol% deionized (DI) water at constant potential (50 V) for 1 h at room temperature. Physical properties of the TiO2 NTs, which were prepared via one and two-step anodization, were investigated. Atomic Force Microscopy (AFM) analysis revealed that anodization and subsequently peeled off the TiO2 NTs caused to the periodic pattern on the Ti surface. In order To study the nanotubes morphology, Field Emission Scanning Electron Microscopy (FESEM) was used, which was revealed that the two-step anodization resulted highly ordered hexagonal TiO2 NTs. Crystal structures of the TiO2 NTs were mainly anatase, determined by X-ray diffraction analysis. Optical studies were performed by Diffuse Reflection Spectra (DRS) and Photoluminescence (PL) analysis showed that the band gap of TiO2 NTs prepared via two-step anodization was lower than the band gap of samples prepared by one-step anodization process.

  1. Processing real-world waste plastics by pyrolysis-reforming for hydrogen and high-value carbon nanotubes.

    Science.gov (United States)

    Wu, Chunfei; Nahil, Mohamad A; Miskolczi, Norbert; Huang, Jun; Williams, Paul T

    2014-01-01

    Producing both hydrogen and high-value carbon nanotubes (CNTs) derived from waste plastics is reported here using a pyrolysis-reforming technology comprising a two-stage reaction system, in the presence of steam and a Ni-Mn-Al catalyst. The waste plastics consisted of plastics from a motor oil container (MOC), commercial waste high density polyethylene (HDPE) and regranulated HDPE waste containing polyvinyl chloride (PVC). The results show that hydrogen can be produced from the pyrolysis-reforming process, but also carbon nanotubes are formed on the catalyst. However, the content of 0.3 wt.% polyvinyl chloride in the waste HDPE (HDPE/PVC) has been shown to poison the catalyst and significantly reduce the quantity and purity of CNTs. The presence of sulfur has shown less influence on the production of CNTs in terms of quantity and CNT morphologies. Around 94.4 mmol H2 g(-1) plastic was obtained for the pyrolysis-reforming of HDPE waste in the presence of the Ni-Mn-Al catalyst and steam at a reforming temperature of 800 °C. The addition of steam in the process results in an increase of hydrogen production and reduction of carbon yield; in addition, the defects of CNTs, for example, edge dislocations were found to be increased with the introduction of steam (from Raman analysis).

  2. High-Purity Semiconducting Single-Walled Carbon Nanotubes: A Key Enabling Material in Emerging Electronics.

    Science.gov (United States)

    Lefebvre, Jacques; Ding, Jianfu; Li, Zhao; Finnie, Paul; Lopinski, Gregory; Malenfant, Patrick R L

    2017-10-17

    Semiconducting single-walled carbon nanotubes (sc-SWCNTs) are emerging as a promising material for high-performance, high-density devices as well as low-cost, large-area macroelectronics produced via additive manufacturing methods such as roll-to-roll printing. Proof-of-concept demonstrations have indicated the potential of sc-SWCNTs for digital electronics, radiofrequency circuits, radiation hard memory, improved sensors, and flexible, stretchable, conformable electronics. Advances toward commercial applications bring numerous opportunities in SWCNT materials development and characterization as well as fabrication processes and printing technologies. Commercialization in electronics will require large quantities of sc-SWCNTs, and the challenge for materials science is the development of scalable synthesis, purification, and enrichment methods. While a few synthesis routes have shown promising results in making near-monochiral SWCNTs, gram quantities are available only for small-diameter sc-SWCNTs, which underperform in transistors. Most synthesis routes yield mixtures of SWCNTs, typically 30% metallic and 70% semiconducting, necessitating the extraction of sc-SWCNTs from their metallic counterparts in high purity using scalable postsynthetic methods. Numerous routes to obtain high-purity sc-SWCNTs from raw soot have been developed, including density-gradient ultracentrifugation, chromatography, aqueous two-phase extraction, and selective DNA or polymer wrapping. By these methods (termed sorting or enrichment), >99% sc-SWCNT content can be achieved. Currently, all of these approaches have drawbacks and limitations with respect to electronics applications, such as excessive dilution, expensive consumables, and high ionic impurity content. Excess amount of dispersant is a common challenge that hinders direct inclusion of sc-SWCNTs into electronic devices. At present, conjugated polymer extraction may represent the most practical route to sc-SWCNTs. By the use of

  3. High-performance carbon-nanotube-based complementary field-effect-transistors and integrated circuits with yttrium oxide

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Shibo; Zhang, Zhiyong, E-mail: zyzhang@pku.edu.cn; Si, Jia; Zhong, Donglai; Peng, Lian-Mao, E-mail: lmpeng@pku.edu.cn [Key Laboratory for the Physics and Chemistry of Nanodevices, Department of Electronics, Peking University, Beijing 100871 (China)

    2014-08-11

    High-performance p-type carbon nanotube (CNT) transistors utilizing yttrium oxide as gate dielectric are presented by optimizing oxidization and annealing processes. Complementary metal-oxide-semiconductor (CMOS) field-effect-transistors (FETs) are then fabricated on CNTs, and the p- and n-type devices exhibit symmetrical high performances, especially with low threshold voltage near to zero. The corresponding CMOS CNT inverter is demonstrated to operate at an ultra-low supply voltage down to 0.2 V, while displaying sufficient voltage gain, high noise margin, and low power consumption. Yttrium oxide is proven to be a competitive gate dielectric for constructing high-performance CNT CMOS FETs and integrated circuits.

  4. Carbon nanotube filters

    Science.gov (United States)

    Srivastava, A.; Srivastava, O. N.; Talapatra, S.; Vajtai, R.; Ajayan, P. M.

    2004-09-01

    Over the past decade of nanotube research, a variety of organized nanotube architectures have been fabricated using chemical vapour deposition. The idea of using nanotube structures in separation technology has been proposed, but building macroscopic structures that have controlled geometric shapes, density and dimensions for specific applications still remains a challenge. Here we report the fabrication of freestanding monolithic uniform macroscopic hollow cylinders having radially aligned carbon nanotube walls, with diameters and lengths up to several centimetres. These cylindrical membranes are used as filters to demonstrate their utility in two important settings: the elimination of multiple components of heavy hydrocarbons from petroleum-a crucial step in post-distillation of crude oil-with a single-step filtering process, and the filtration of bacterial contaminants such as Escherichia coli or the nanometre-sized poliovirus (~25 nm) from water. These macro filters can be cleaned for repeated filtration through ultrasonication and autoclaving. The exceptional thermal and mechanical stability of nanotubes, and the high surface area, ease and cost-effective fabrication of the nanotube membranes may allow them to compete with ceramic- and polymer-based separation membranes used commercially.

  5. In situ synthesis of oriented NiS nanotube arrays on FTO as high-performance counter electrode for dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yan, E-mail: liyan-nwnu@163.com [Key Laboratory of Atomic and Molecular Physics & Functional Materials of Gansu Province, College of Physics and Electronic Engineering, Northwest Normal University, Lanzhou, 730070 (China); Chang, Yin [Key Laboratory of Atomic and Molecular Physics & Functional Materials of Gansu Province, College of Physics and Electronic Engineering, Northwest Normal University, Lanzhou, 730070 (China); Zhao, Yun [Laboratory of Clean Energy Chemistry and Materials, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, 730000 (China); Wang, Jian; Wang, Cheng-wei [Key Laboratory of Atomic and Molecular Physics & Functional Materials of Gansu Province, College of Physics and Electronic Engineering, Northwest Normal University, Lanzhou, 730070 (China)

    2016-09-15

    Oriented nickel sulfide (NiS) nanotube arrays were successfully in-situ fabricated on conductive glass substrate and used directly as counter electrode for dye-sensitized solar cells without any post-processing. Compared with Pt counter electrode, for the beneficial effect of electronic transport along the axial direction through the arrays to the substrate, oriented NiS nanotube arrays exhibit both higher electrocatalytic activity for I{sub 3}{sup −} reduction and better electrochemical stability, resulting in a significantly improved power conversion efficiency of 9.8%. Such in-situ grown oriented sulfide semiconductor nanotube arrays is expected to lead a new class structure of composites for highly efficient cathode materials. - Highlights: • In-situ synthesis strategy was proposed to construct oriented NiS nanotube arrays. • Such oriented tube nanostructure benefits the electronic transport along the axial direction of the arrays. • As CE of DSSCs, NiS nanotube arrays exhibit both higher efficiency (9.8%) and electrochemical stability than Pt.

  6. Facile fabrication of polyaniline nanotubes using the self-assembly behavior based on the hydrogen bonding: a mechanistic study and application in high-performance electrochemical supercapacitor electrode

    International Nuclear Information System (INIS)

    Wu, Wenling; Pan, Duo; Li, Yanfeng; Zhao, Guanghui; Jing, Lingyun; Chen, Suli

    2015-01-01

    At present, the in situ synthesis of polyaniline (PANI) nanotubes via self-assembly of organic dopant acid is a particularly charming task in supercapacitors. Herein, we report the formation of uniform PANI nanotubes doped with malic acid (MA) and other organic acids, such as propionic acid (PA), succinic acid (SA), tartaric acid (TA) and citric acid (CA), which simultaneously acts as a dopant acid as well as a structure-directing agent. The morphology, structure and thermal stability of PANI nanotubes were characterized by means of scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), Raman spectra, Ultraviolet-visible spectra (UV–vis), X-ray diffraction (XRD), thermogravimetric analysis (TGA). Meanwhile, the electrochemical performance of the fabricated electrodes was evaluated by cyclic voltammetry (CV), galvanostatic charge/discharge (GCD), and electrochemical impedance spectroscopy (EIS). Furthermore, the PANI-MA and PANI-CA nanotubes, with [aniline]/[acid] molar ratio of 4:1, possessed highest specific capacitance of 658 F/g and 617 F/g at the current density of 0.1 A/g in 1.0 M H 2 SO 4 electrolyte due to their unique nanotubular structures. It makes PANI nanotubes a promising electrode material for high performance supercapacitors

  7. Structural transformations of carbon chains inside nanotubes

    International Nuclear Information System (INIS)

    Warner, Jamie H.; Ruemmeli, Mark H.; Bachmatiuk, Alicja; Buechner, Bernd

    2010-01-01

    In situ aberration-corrected high-resolution transmission electron microscopy is used to examine the structural transformations of carbon chains that occur in the interior region of carbon nanotubes. We find electron-beam irradiation leads to the formation of two-dimensional carbon structures that are freely mobile inside the nanotube. The inner diameter of the nanotube influences the structural transformations of the carbon chains. As the diameter of the nanotube increases, electron-beam irradiation leads to curling of the chains and eventually the formation of closed looped structures. The closed looped structures evolve into spherical fullerenelike structures that exhibit translational motion inside the nanotubes and also coalesce to form larger nanotube structures. These results demonstrate the use of carbon nanotubes as test tubes for growing small carbon nanotubes within the interior by using only electron-beam irradiation at 80 kV.

  8. Synthesis of highly dispersed platinum particles on carbon nanotubes by an in situ vapor-phase method

    Energy Technology Data Exchange (ETDEWEB)

    Mercado-Zúñiga, C. [Depto. Ing. Metalurgia y Materiales, Instituto Politecnico Nacional, Mexico 07300 D.F. (Mexico); Vargas-García, J.R., E-mail: rvargasga@ipn.mx [Depto. Ing. Metalurgia y Materiales, Instituto Politecnico Nacional, Mexico 07300 D.F. (Mexico); Hernández-Pérez, M.A. [Depto. Ing. Metalurgia y Materiales, Instituto Politecnico Nacional, Mexico 07300 D.F. (Mexico); Figueroa-Torres, M.Z. [Depto. Eco-Materiales y Energia, Univ. Autonoma de Nuevo Leon, Nuevo Leon 66450 (Mexico); Cervantes-Sodi, F. [Depto. Fisica y Matematicas, Univ. Iberoamericana, Mexico 01209 D.F. (Mexico); Torres-Martínez, L.M. [Depto. Eco-Materiales y Energia, Univ. Autonoma de Nuevo Leon, Nuevo Leon 66450 (Mexico)

    2014-12-05

    Highlights: • Highly dispersed Pt nanoparticles were prepared on functionalized carbon nanotubes. • A simple and competitive vapor-phase method was employed. • Carbonyl groups were assumed to be responsible for assisted decomposition of Pt-acac. • Pt particles were highly dispersed because carbonyl groups served as reaction sites. • Particles of 2.3 nm in size were highly dispersed even the high loading (27 wt%Pt). - Abstract: Highly dispersed Pt nanoparticles were prepared on functionalized multi-walled carbon nanotubes (f-MWCNTs) using a simple in situ vapor-phase method. The method consisted in two-step procedure in which an initial mixture of Pt precursor (Pt-acac) and f-MWCNTs was heated in a quartz tube reactor, first at 180 °C and then at 400 °C. Fourier transform infrared spectroscopy (FTIR–ATR), thermal gravimetric analysis (TGA) and X-ray diffraction (XRD) were used to follow the chemical and structural transformations of mixture components during heating steps. The functionalization of MWCNTs with HNO{sub 3}/H{sub 2}SO{sub 4} solution resulted in formation of surface carbonyl groups. The FTIR–ATR and XRD results indicated that individual Pt-acac withstood heating at 180 °C, whereas it was dissociated when heated in contact with f-MWCNTs at the same temperature. Thus, the functional carbonyl groups were found to be responsible for assisted decomposition of Pt-acac at 180 °C. Since carbonyl groups served as reaction sites for decomposition of Pt-acac, the resulting particles were highly and homogeneously dispersed on the surface of MWCNTs even the relatively high metallic loading of 27 wt%. TEM observations revealed that crystalline Pt particles exhibit narrow size distribution with a mean size of 2.3 nm.

  9. Synthesis of highly dispersed platinum particles on carbon nanotubes by an in situ vapor-phase method

    International Nuclear Information System (INIS)

    Mercado-Zúñiga, C.; Vargas-García, J.R.; Hernández-Pérez, M.A.; Figueroa-Torres, M.Z.; Cervantes-Sodi, F.; Torres-Martínez, L.M.

    2014-01-01

    Highlights: • Highly dispersed Pt nanoparticles were prepared on functionalized carbon nanotubes. • A simple and competitive vapor-phase method was employed. • Carbonyl groups were assumed to be responsible for assisted decomposition of Pt-acac. • Pt particles were highly dispersed because carbonyl groups served as reaction sites. • Particles of 2.3 nm in size were highly dispersed even the high loading (27 wt%Pt). - Abstract: Highly dispersed Pt nanoparticles were prepared on functionalized multi-walled carbon nanotubes (f-MWCNTs) using a simple in situ vapor-phase method. The method consisted in two-step procedure in which an initial mixture of Pt precursor (Pt-acac) and f-MWCNTs was heated in a quartz tube reactor, first at 180 °C and then at 400 °C. Fourier transform infrared spectroscopy (FTIR–ATR), thermal gravimetric analysis (TGA) and X-ray diffraction (XRD) were used to follow the chemical and structural transformations of mixture components during heating steps. The functionalization of MWCNTs with HNO 3 /H 2 SO 4 solution resulted in formation of surface carbonyl groups. The FTIR–ATR and XRD results indicated that individual Pt-acac withstood heating at 180 °C, whereas it was dissociated when heated in contact with f-MWCNTs at the same temperature. Thus, the functional carbonyl groups were found to be responsible for assisted decomposition of Pt-acac at 180 °C. Since carbonyl groups served as reaction sites for decomposition of Pt-acac, the resulting particles were highly and homogeneously dispersed on the surface of MWCNTs even the relatively high metallic loading of 27 wt%. TEM observations revealed that crystalline Pt particles exhibit narrow size distribution with a mean size of 2.3 nm

  10. Direct electrodeposition of highly ordered gold nanotube arrays for use in non-enzymatic amperometric sensing of glucose

    International Nuclear Information System (INIS)

    Tian, Taolei; Dong, Junping; Xu, Jiaqiang

    2016-01-01

    The authors describe vertically aligned gold nanotube arrays (Au-NTAs) and gold nanowire arrays (Au-NWAs) that were directly grown in alumina oxide templates by galvanostatic deposition. The morphology of the gold arrays can be controlled by adjusting the pH value of the plating bath. Scanning electron microscopy shows the nanoarrays to be highly ordered (with an average length of around 2 μm), and the opening width of the gold nanotube arrays to be uniform (with diameters of around 50 nm). The electrocatalytic activities of the Au-NTAs and Au-NWAs deposited on a glassy carbon electrode toward glucose oxidation were compared by cyclic voltammetry and amperometry at pH 7.2. The Au-NTAs yield higher amperometric currents. The respective glucose sensor, when operated at a working potential of 0.25 V (vs. SCE), exhibits a linear range that extends from 5 μM to 16.4 mM concentrations of glucose, a sensitivity of 44.2 μA mM"−"1 cm"−"2, and a detection limit of 2.1 μM (at an S/N ratio of 3). The excellent sensing performance is attributed to the large surface area and the fast electron transfer rate for the one-dimensional gold nanoarrays (author)

  11. High utilization platinum deposition on single-walled carbon nanotubes as catalysts for direct methanol fuel cell

    International Nuclear Information System (INIS)

    Wang, J.J.; Yin, G.P.; Zhang, J.; Wang, Z.B.; Gao, Y.Z.

    2007-01-01

    This research aims to enhance the activity of Pt catalysts, thus to lower the loading of Pt metal in fuel cell. Highly dispersed platinum supported on single-walled carbon nanotubes (SWNTs) as catalyst was prepared by ion exchange method. The homemade Pt/SWNTs underwent a repetition of ion exchange and reduction process in order to achieve an increase of the metal loading. For comparison, the similar loading of Pt catalyst supported on carbon nanotubes was prepared by borohydride reduction method. The catalysts were characterized by using energy dispersive analysis of X-ray (EDAX), transmission electron micrograph (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectrum (XPS). Compared with the Pt/SWNTs catalyst prepared by borohydride method, higher Pt utilization was achieved on the SWNTs by ion exchange method. Furthermore, in comparison to the E-TEK 20 wt.% Pt/C catalyst with the support of carbon black, the results from electrochemical measurement indicated that the Pt/SWNTs prepared by ion exchange method displayed a higher catalytic activity for methanol oxidation and higher Pt utilization, while no significant increasing in the catalytic activity of the Pt/SWNTs catalyst obtained by borohydride method

  12. Highly purified, multi-wall carbon nanotubes induce light-chain 3B expression in human lung cells

    International Nuclear Information System (INIS)

    Tsukahara, Tamotsu; Matsuda, Yoshikazu; Usui, Yuki; Haniu, Hisao

    2013-01-01

    Highlights: •HTT2800-treated BEAS-2B cells induced LC3B in a time-dependent manner. •HTT2800-treated BEAS-2B cells showed decreased cell proliferation that was both time- and dose-dependent. •Addition of 3-MA, LC3B-II protein and mRNA levels were significantly decreased. •3-MA and E64-d + pepstatin A, but not brefeldin A, provided protection against HTT2800-induced cell death. •These results suggest that HTT2800 predominantly causes autophagy rather than apoptotic cell death in BEAS-2B cells. -- Abstract: Bronchial epithelial cells are targets of inhalation and play a critical role in the maintenance of mucosal integrity as mechanical barriers against various particles. Our previous result suggest that vapor-grown carbon fiber, HTT2800, which is one of the most highly purified multi-wall carbon nanotubes (MWCNT) showed cellular uptake of the carbon nanotube, increased cell death, enhanced DNA damage, and induced cytokine release. Increasing evidence suggests that autophagy may critically influence vital cellular processes such as apoptosis, cell proliferation and inflammation and thereby may play a critical role in pulmonary diseases. Autophagy was recently recognized as a critical cell death pathway, and autophagosome accumulation has been found to be associated with the exposure of various nanoparticles. In this study, the authors focus on the autophagic responses of HTT2800 exposure. The HTT2800-exposed cells induced LC3B expression and induced cell growth inhibition

  13. Highly purified, multi-wall carbon nanotubes induce light-chain 3B expression in human lung cells

    Energy Technology Data Exchange (ETDEWEB)

    Tsukahara, Tamotsu, E-mail: ttamotsu@kanazawa-med.ac.jp [Department of Hematology and Immunology, Kanazawa Medical University, 1-1 Daigaku, Uchinada, Ishikawa 920-0293 (Japan); Matsuda, Yoshikazu [Clinical Pharmacology Educational Center, Nihon Pharmaceutical University, Ina-machi, Saitama 362-0806 (Japan); Usui, Yuki [Research Center for Exotic Nanocarbons, Shinshu University, 4-17-1 Wakasato, Nagano-shi, Nagano 380-8553 (Japan); Haniu, Hisao [Department of Orthopaedic Surgery, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto, Nagano 390-8621 (Japan)

    2013-10-18

    Highlights: •HTT2800-treated BEAS-2B cells induced LC3B in a time-dependent manner. •HTT2800-treated BEAS-2B cells showed decreased cell proliferation that was both time- and dose-dependent. •Addition of 3-MA, LC3B-II protein and mRNA levels were significantly decreased. •3-MA and E64-d + pepstatin A, but not brefeldin A, provided protection against HTT2800-induced cell death. •These results suggest that HTT2800 predominantly causes autophagy rather than apoptotic cell death in BEAS-2B cells. -- Abstract: Bronchial epithelial cells are targets of inhalation and play a critical role in the maintenance of mucosal integrity as mechanical barriers against various particles. Our previous result suggest that vapor-grown carbon fiber, HTT2800, which is one of the most highly purified multi-wall carbon nanotubes (MWCNT) showed cellular uptake of the carbon nanotube, increased cell death, enhanced DNA damage, and induced cytokine release. Increasing evidence suggests that autophagy may critically influence vital cellular processes such as apoptosis, cell proliferation and inflammation and thereby may play a critical role in pulmonary diseases. Autophagy was recently recognized as a critical cell death pathway, and autophagosome accumulation has been found to be associated with the exposure of various nanoparticles. In this study, the authors focus on the autophagic responses of HTT2800 exposure. The HTT2800-exposed cells induced LC3B expression and induced cell growth inhibition.

  14. Highly efficient photoelectrochemical performance of SrTiO{sub 3}/TiO{sub 2} heterojunction nanotube array thin film

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Yan [Qingdao University, School of Chemistry, Chemical Engineering and Environments (China); Bu Yuyu [Chinese Academy of Sciences, National Engineering Center of Marine Corrosion Protection, Institute of Oceanology (China); Yu Jianqiang, E-mail: yjq@licp.cas.cn; Li Ping [Qingdao University, School of Chemistry, Chemical Engineering and Environments (China)

    2013-06-15

    SrTiO{sub 3}-TiO{sub 2} heterojunction thin-film nanotube arrays (SNTs, the average inner diameter is about 50 nm) was fabricated via electrochemical anodization followed by a hydrothermal treatment. The photo-to-current conversion properties and the photoelectrochemical performance for cathodic protection of carbon steel in 0.5 M of sodium chloride solution under white light illumination were investigated. The results showed that the highly ordered nanotube arrays could provide very excellent cathodic protection for carbon steel under white light irradiation.

  15. Carbon hybridized halloysite nanotubes for high-performance hydrogen storage capacities

    Science.gov (United States)

    Jin, Jiao; Fu, Liangjie; Yang, Huaming; Ouyang, Jing

    2015-01-01

    Hybrid nanotubes of carbon and halloysite nanotubes (HNTs) with different carbon:HNTs ratio were hydrothermally synthesized from natural halloysite and sucrose. The samples display uniformly cylindrical hollow tubular structure with different morphologies. These hybrid nanotubes were concluded to be promising medium for physisorption-based hydrogen storage. The hydrogen adsorption capacity of pristine HNTs was 0.35% at 2.65 MPa and 298 K, while that of carbon coated HNTs with the pre-set carbon:HNTs ratio of 3:1 (3C-HNTs) was 0.48% under the same condition. This carbon coated method could offer a new pattern for increasing the hydrogen adsorption capacity. It was also possible to enhance the hydrogen adsorption capacity through the spillover mechanism by incorporating palladium (Pd) in the samples of HNTs (Pd-HNTs) and 3C-HNTs (Pd-3C-HNTs and 3C-Pd-HNTs are the samples with different location of Pd nanoparticles). The hydrogen adsorption capacity of the Pd-HNTs was 0.50% at 2.65 MPa and 298 K, while those of Pd-3C-HNTs and 3C-Pd-HNTs were 0.58% and 0.63%, respectively. In particular, for this spillover mechanism of Pd-carbon-HNTs ternary system, the bidirectional transmission of atomic and molecular hydrogen (3C-Pd-HNTs) was concluded to be more effective than the unidirectional transmission (Pd-3C-HNTs) in this work for the first time. PMID:26201827

  16. High performance dye-sensitized solar cell based on hydrothermally deposited multiwall carbon nanotube counter electrode

    Science.gov (United States)

    Siriroj, Sumeth; Pimanpang, Samuk; Towannang, Madsakorn; Maiaugree, Wasan; Phumying, Santi; Jarernboon, Wirat; Amornkitbamrung, Vittaya

    2012-06-01

    Conductive glass was coated with multiwall carbon nanotubes (MWCNTs) by a hydrothermal method. MWCNTs films were subsequently used as dye-sensitized solar cell (DSSC) counter electrodes. The performance of hydrothermal MWCNT DSSC was ˜2.37%. After film annealing in an Ar atmosphere, annealed-hydrothermal MWCNT (AHT-CNT) DSSC efficiency was significantly increased to ˜7.66%, in comparison to ˜8.01% for sputtered-Pt DSSC. Improvement of AHT-CNT DSSC performance is attributed to a decrease in charge-transfer resistance from 1500 Ω to 30 Ω as observed by electrochemical impedance spectroscopy.

  17. Highly enhanced vapor sensing of multi-walled carbon nanotube network sensors by n-butylamine functionalization

    Czech Academy of Sciences Publication Activity Database

    Slobodian, P.; Říha, Pavel; Cavallo, P.; Barbero, C.A.; Cvelbar, U.; Benlikaya, R.; Petras, D.; Sáha, P.

    2014-01-01

    Roč. 2014, August (2014), Article ID 589627 ISSN 1687-4110 Grant - others:UTB Zlín(CZ) IGA/FT/2014/013; GA MŠk(CZ) ED2.1.00/03.0111; GA MŠk(CZ) 7AMB13AR019 Institutional support: RVO:67985874 Keywords : carbon nanotube (CNT) * multiwall carbon nanotube (MWCNT) * nanotube networks * volatile organic compounds (VOC) Subject RIV: BK - Fluid Dynamics Impact factor: 1.644, year: 2014

  18. Vertically Aligned Co9 S8 Nanotube Arrays onto Graphene Papers as High-Performance Flexible Electrodes for Supercapacitors.

    Science.gov (United States)

    Xiong, Dongbin; Li, Xifei; Bai, Zhimin; Li, Jianwei; Han, Yan; Li, Dejun

    2018-02-16

    Paper-like electrodes are emerging as a new category of advanced electrodes for flexible supercapacitors (SCs). Graphene, a promising two-dimensional material with high conductivity, can be easily processed into papers. Here, we report a rational design of flexible architecture with Co 9 S 8 nanotube arrays (NAs) grown onto graphene paper (GP) via a facile two-step hydrothermal method. When employed as flexible free-standing electrode for SCs, the proposed architectured Co 9 S 8 /GPs exhibits superior electrochemical performance with ultrahigh capacitance and outstanding rate capability (469 F g -1 at 10 A g -1 ). These results demonstrate that the new nanostructured Co 9 S 8 /GPs can be potentially applied in high performance flexible supercapacitors. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Analyses of residual iron in carbon nanotubes produced by camphor/ferrocene pyrolysis and purified by high temperature annealing

    Energy Technology Data Exchange (ETDEWEB)

    Antunes, E.F., E-mail: ericafa@las.inpe.br [Instituto Tecnologico de Aeronautica (ITA), Praca Marechal Eduardo Gomes, 50, CEP 12.228-900, Sao Jose dos Campos, SP (Brazil); Instituto Nacional de Pesquisas Espaciais (INPE), Av. dos Astronautas, 1758, CEP 12.227-010, Sao Jose dos Campos, SP (Brazil); Resende, V.G. de; Mengui, U.A. [Instituto Nacional de Pesquisas Espaciais (INPE), Av. dos Astronautas, 1758, CEP 12.227-010, Sao Jose dos Campos, SP (Brazil); Cunha, J.B.M. [Universidade Federal do Rio Grande do Sul (UFRGS), Av. Bento Goncalves, 9500, CEP 91.501-970, Porto Alegre, RS (Brazil); Corat, E.J.; Massi, M. [Instituto Nacional de Pesquisas Espaciais (INPE), Av. dos Astronautas, 1758, CEP 12.227-010, Sao Jose dos Campos, SP (Brazil)

    2011-07-01

    A detailed analysis of iron-containing phases in multiwall carbon nanotube (MWCNT) powder was carried out. The MWCNTs were produced by camphor/ferrocene and purified by high temperature annealing in an oxygen-free atmosphere (N{sub 2} or VC). Thermogravimetric analysis, Moessbauer spectroscopy, X-ray diffraction and X-ray photoelectron spectroscopy enabled the evaluation of the residual iron in MWCNTs after purification. The VC treatments provided MWCNTs with a purity degree higher than 99%. Moreover, Raman spectroscopy revealed a significant improvement in graphitic ordering after thermal annealing. A brief description of the mechanism of iron removal was included. We highlight the mobility of iron atoms through graphitic sheets and the large contact angle of iron clusters formed on MWCNT surfaces at high temperatures.

  20. Highly sensitive piezo-resistive graphite nanoplatelet-carbon nanotube hybrids/polydimethylsilicone composites with improved conductive network construction.

    Science.gov (United States)

    Zhao, Hang; Bai, Jinbo

    2015-05-13

    The constructions of internal conductive network are dependent on microstructures of conductive fillers, determining various electrical performances of composites. Here, we present the advanced graphite nanoplatelet-carbon nanotube hybrids/polydimethylsilicone (GCHs/PDMS) composites with high piezo-resistive performance. GCH particles were synthesized by the catalyst chemical vapor deposition approach. The synthesized GCHs can be well dispersed in the matrix through the mechanical blending process. Due to the exfoliated GNP and aligned CNTs coupling structure, the flexible composite shows an ultralow percolation threshold (0.64 vol %) and high piezo-resistive sensitivity (gauge factor ∼ 10(3) and pressure sensitivity ∼ 0.6 kPa(-1)). Slight motions of finger can be detected and distinguished accurately using the composite film as a typical wearable sensor. These results indicate that designing the internal conductive network could be a reasonable strategy to improve the piezo-resistive performance of composites.

  1. Synthesis of highly dispersed Pd nanoparticles supported on multi-walled carbon nanotubes and their excellent catalytic performance for oxidation of benzyl alcohol

    NARCIS (Netherlands)

    Shinde, V.M.; Skupien, E.; Makkee, M.

    2015-01-01

    Narrow sized and highly homogeneous dispersed Pd nanoparticles have been synthesized on nitric acid-functionalized multi-walled carbon nanotubes (CNTs) without a capping agent. The TEM images show that the extremely small Pd nanoparticles with an average size of about 1.5 nm were homogeneously

  2. Observation of high Tc one dimensional superconductivity in 4 angstrom carbon nanotube arrays

    KAUST Repository

    Zhang, Bing; Liu, Yang; Chen, Qihong; Lai, Zhiping; Sheng, Ping

    2017-01-01

    The only known approach to fabricate large, uniform arrays of 4-Å single wall carbon nanotubes (SWNTs) is by using zeolite crystals as the template, in which the nanotubes are formed by chemical vapor deposition inside the linear channels of the AlPO-5 (AFI for short) zeolite. However, up to now the pore filling factor has been very low, as evidenced by the weight percentage of carbon in thermal gravimetric analysis (TGA) measurements. In this work, we show that by using a new, micro-platelet AFI crystals as the template, combined with the use of a new CVD process, we can increase the TGA result to 22.5wt%, which translates to a pore filling factor of 91%. We have observed one dimensional (1D) superconductivity in such samples. The temperature dependence of resistance shows a smooth decreasing trend below 60 K, and the differential resistance displays a gap that disappears above the 1D superconducting initiation temperature. The observed behaviour is shown to agree very well with the theoretical predictions of 1D superconductivity.

  3. High-performance carbon nanotube-implanted mesoporous carbon spheres for supercapacitors with low series resistance

    Energy Technology Data Exchange (ETDEWEB)

    Yi, Bin [College of Materials Science and Engineering, Hunan University, Changsha 410082 (China); Chen, Xiaohua, E-mail: hudacxh62@yahoo.com.cn [College of Materials Science and Engineering, Hunan University, Changsha 410082 (China); Guo, Kaimin [College of Physics and Electronic Science, Changsha University of Science and Technology (China); Xu, Longshan [Department of Mechanical Engineering, Xiamen University of Technology, Xiamen 361024 (China); Chen, Chuansheng [College of Physics and Electronic Science, Changsha University of Science and Technology (China); Yan, Haimei; Chen, Jianghua [College of Materials Science and Engineering, Hunan University, Changsha 410082 (China)

    2011-11-15

    Research highlights: {yields} CNTs-implanted porous carbon spheres are prepared by using gelatin as soft template. {yields} Homogeneously distributed CNTs form a well-develop network in carbon spheres. {yields} CNTs act as a reinforcing backbone assisting the formation of pore structure. {yields} CNTs improve electrical conductivity and specific capacitance of supercapacitor. -- Abstract: Carbon nanotube-implanted mesoporous carbon spheres were prepared by an easy polymerization-induced colloid aggregation method using gelatin as a soft template. Scanning electron microscopy, transmission electron microscopy and nitrogen adsorption-desorption measurements reveal that the materials are mesoporous carbon spheres, with a diameter of {approx}0.5-1.0 {mu}m, a specific surface area of 284 m{sup 2}/g and average pore size of 3.9 nm. Using the carbon nanotube-implanted mesoporous carbon spheres as electrode material for supercapacitors in an aqueous electrolyte solution, a low equivalent series resistance of 0.83 {Omega} cm{sup 2} and a maximum specific capacitance of 189 F/g with a measured power density of 8.7 kW/kg at energy density of 6.6 Wh/kg are obtained.

  4. Observation of high Tc one dimensional superconductivity in 4 angstrom carbon nanotube arrays

    KAUST Repository

    Zhang, Bing

    2017-02-14

    The only known approach to fabricate large, uniform arrays of 4-Å single wall carbon nanotubes (SWNTs) is by using zeolite crystals as the template, in which the nanotubes are formed by chemical vapor deposition inside the linear channels of the AlPO-5 (AFI for short) zeolite. However, up to now the pore filling factor has been very low, as evidenced by the weight percentage of carbon in thermal gravimetric analysis (TGA) measurements. In this work, we show that by using a new, micro-platelet AFI crystals as the template, combined with the use of a new CVD process, we can increase the TGA result to 22.5wt%, which translates to a pore filling factor of 91%. We have observed one dimensional (1D) superconductivity in such samples. The temperature dependence of resistance shows a smooth decreasing trend below 60 K, and the differential resistance displays a gap that disappears above the 1D superconducting initiation temperature. The observed behaviour is shown to agree very well with the theoretical predictions of 1D superconductivity.

  5. Highly conductive carbon nanotube buckypapers with improved doping stability via conjugational cross-linking.

    Science.gov (United States)

    Chen, I-Wen Peter; Liang, Richard; Zhao, Haibo; Wang, Ben; Zhang, Chuck

    2011-12-02

    Carbon nanotube (CNT) sheets or buckypapers have demonstrated promising electrical conductivity and mechanical performance. However, their electrical conductivity is still far below the requirements for engineering applications, such as using as a substitute for copper mesh, which is currently used in composite aircraft structures for lightning strike protection. In this study, different CNT buckypapers were stretched to increase their alignment, and then subjected to conjugational cross-linking via chemical functionalization. The conjugationally cross-linked buckypapers (CCL-BPs) demonstrated higher electrical conductivity of up to 6200 S cm( - 1), which is more than one order increase compared to the pristine buckypapers. The CCL-BPs also showed excellent doping stability in over 300 h in atmosphere and were resistant to degradation at elevated temperatures. The tensile strength of the stretched CCL-BPs reached 220 MPa, which is about three times that of pristine buckypapers. We attribute these property improvements to the effective and stable conjugational cross-links of CNTs, which can simultaneously improve the electrical conductivity, doping stability and mechanical properties. Specifically, the electrical conductivity increase resulted from improving the CNT alignment and inter-tube electron transport capability. The conjugational cross-links provide effective 3D conductive paths to increase the mobility of electrons among individual nanotubes. The stable covalent bonding also enhances the thermal stability and load transfer. The significant electrical and mechanical property improvement renders buckypaper a multifunctional material for various applications, such as conducting composites, battery electrodes, capacitors, etc.

  6. Kramers-Kronig method for determination of optical properties of PZT nanotubes fabricated by sol-gel method and porous anodic alumina with high aspect ratio

    Science.gov (United States)

    Pakizeh, Esmaeil; Moradi, Mahmood

    2018-03-01

    Ferroelectric Pb(ZrTi)O3 (PZT) nanotubes were prepared by sol-gel method and porous anodic alumina (PAA) membrane using spin-coating technique. This method is based on filling-pyrolysis-filling process and the use of one-stage alumina membranes. One of the advantages of this method is its rapidity, which takes only 1 h time before the calcination step. The effect of repeated pores filling was investigated to get the required size of nanotubes. The field emission scanning electron microscope (FE-SEM) images were shown that the PZT nanotubes have inner diameters in the range of 65-90 nm and length of about 50-60 μm. This means that the samples have a significant aspect ratio (700-800). Also the FE-SEM image confirmed that the highly ordered, hexagonally distributed PAA membranes with the pore diameter about 140-150 nm were formed. The X-ray diffraction (XRD) results showed that the PZT nanotubes have a tetragonal structure. The metal oxide bands like ZrO6 and TiO6 of the final PZT nanotubes were detected by Fourier transform infrared (FT-IR) analysis and confirmed the formation of perovskite structure. By using FT-IR spectroscopy and Kramers-Kronig transformation method, the optical constants like real 𝜀1(ω) and imaginary 𝜀2(ω) parts of dielectric function, extinction coefficient k(ω) and refractive index n(ω) were determined. It was shown that the optical constants of PZT nanotubes are different from PZT nanoparticles.

  7. Structural properties of water around uncharged and charged carbon nanotubes

    International Nuclear Information System (INIS)

    Dezfoli, Amir Reza Ansari; Mehrabian, Mozaffar Ali; Rafsanjani, Hassan Hashemipour

    2013-01-01

    Studying the structural properties of water molecules around the carbon nanotubes is very important in a wide variety of carbon nanotubes applications. We studied the number of hydrogen bonds, oxygen and hydrogen density distributions, and water orientation around carbon nanotubes. The water density distribution for all carbon nanotubes was observed to have the same feature. In water-carbon nanotubes interface, a high-density region of water molecules exists around carbon nanotubes. The results reveal that the water orientation around carbon nanotubes is roughly dependent on carbon nanotubes surface charge. The water molecules in close distances to carbon nanotubes were found to make an HOH plane nearly perpendicular to the water-carbon nanotubes interface for carbon nanotubes with negative surface charge. For uncharged carbon nanotubes and carbon nanotubes with positive surface charge, the HOH plane was in tangential orientation with water-carbon nanotubes interface. There was also a significant reduction in hydrogen bond of water region around carbon nanotubes as compared with hydrogen bond in bulk water. This reduction was very obvious for carbon nanotubes with positive surface charge. In addition, the calculation of dynamic properties of water molecules in water-CNT interface revealed that there is a direct relation between the number of Hbonds and self-diffusion coefficient of water molecules

  8. Functionalized carbon nanotubes containing isocyanate groups

    International Nuclear Information System (INIS)

    Zhao Chungui; Ji Lijun; Liu Huiju; Hu Guangjun; Zhang Shimin; Yang Mingshu; Yang Zhenzhong

    2004-01-01

    Functionalized carbon nanotubes containing isocyanate groups can extend the nanotube chemistry, and may promote their many potential applications such as in polymer composites and coatings. This paper describes a facile method to prepare functionalized carbon nanotubes containing highly reactive isocyanate groups on its surface via the reaction between toluene 2,4-diisocyanate and carboxylated carbon nanotubes. Fourier-transformed infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) confirmed that reactive isocyanate groups were covalently attached to carbon nanotubes. The content of isocyanate groups were determined by chemical titration and thermogravimetric analysis (TGA)

  9. Synthesis of PbI(2) single-layered inorganic nanotubes encapsulated within carbon nanotubes.

    Science.gov (United States)

    Cabana, Laura; Ballesteros, Belén; Batista, Eudar; Magén, César; Arenal, Raúl; Oró-Solé, Judith; Rurali, Riccardo; Tobias, Gerard

    2014-04-02

    The template assisted growth of single-layered inorganic nanotubes is reported. Single-crystalline lead iodide single-layered nanotubes have been prepared using the inner cavities of carbon nanotubes as hosting templates. The diameter of the resulting inorganic nanotubes is merely dependent on the diameter of the host. This facile method is highly versatile opening up new horizons in the preparation of single-layered nanostructures. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. High-performance multi-functional reverse osmosis membranes obtained by carbon nanotube·polyamide nanocomposite

    Science.gov (United States)

    Inukai, Shigeki; Cruz-Silva, Rodolfo; Ortiz-Medina, Josue; Morelos-Gomez, Aaron; Takeuchi, Kenji; Hayashi, Takuya; Tanioka, Akihiko; Araki, Takumi; Tejima, Syogo; Noguchi, Toru; Terrones, Mauricio; Endo, Morinobu

    2015-01-01

    Clean water obtained by desalinating sea water or by purifying wastewater, constitutes a major technological objective in the so-called water century. In this work, a high-performance reverse osmosis (RO) composite thin membrane using multi-walled carbon nanotubes (MWCNT) and aromatic polyamide (PA), was successfully prepared by interfacial polymerization. The effect of MWCNT on the chlorine resistance, antifouling and desalination performances of the nanocomposite membranes were studied. We found that a suitable amount of MWCNT in PA, 15.5 wt.%, not only improves the membrane performance in terms of flow and antifouling, but also inhibits the chlorine degradation on these membranes. Therefore, the present results clearly establish a solid foundation towards more efficient large-scale water desalination and other water treatment processes. PMID:26333385

  11. Atomic layer deposition of ruthenium on plasma-treated vertically aligned carbon nanotubes for high-performance ultracapacitors.

    Science.gov (United States)

    Kim, Jun Woo; Kim, Byungwoo; Park, Suk Won; Kim, Woong; Shim, Joon Hyung

    2014-10-31

    It is challenging to realize a conformal metal coating by atomic layer deposition (ALD) because of the high surface energy of metals. In this study, ALD of ruthenium (Ru) on vertically aligned carbon nanotubes (CNTs) was carried out. To activate the surface of CNTs that lack surface functional groups essential for ALD, oxygen plasma was applied ex situ before ALD. X-ray photoelectron spectroscopy and Raman spectroscopy confirmed surface activation of CNTs by the plasma pretreatment. Transmission electron microscopy analysis with energy-dispersive x-ray spectroscopy composition mapping showed that ALD Ru grew conformally along CNTs walls. ALD Ru/CNTs were electrochemically oxidized to ruthenium oxide (RuOx) that can be a potentially useful candidate for use in the electrodes of ultracapacitors. Electrode performance of RuOx/CNTs was evaluated using cyclic voltammetry and galvanostatic charge-discharge measurements.

  12. Highly efficient growth of vertically aligned carbon nanotubes on Fe-Ni based metal alloy foils for supercapacitors

    Science.gov (United States)

    Amalina Raja Seman, Raja Noor; Asyadi Azam, Mohd; Ambri Mohamed, Mohd

    2016-12-01

    Supercapacitors are highly promising energy devices with superior charge storage performance and a long lifecycle. Construction of the supercapacitor cell, especially electrode fabrication, is critical to ensure good performance in applications. This work demonstrates direct growth of vertically aligned carbon nanotubes (CNTs) on Fe-Ni based metal alloy foils, namely SUS 310S, Inconel 600 and YEF 50, and their use in symmetric vertically aligned CNT supercapacitor electrodes. Alumina and cobalt thin film catalysts were deposited onto the foils, and then CNT growth was performed using alcohol catalytic chemical vapour deposition. By this method, vertically aligned CNTs were successfully grown and used directly as a binder-free supercapacitor electrode to deliver excellent electrochemical performance. The device showed relatively good specific capacitance, a superior rate capability and excellent cycle stability, maintaining about 96% capacitance up to 1000 cycles.

  13. Hollow Ag-Pd core–shell nanotubes as highly active catalysts for the electro-oxidation of formic acid

    International Nuclear Information System (INIS)

    Jiang Yuanyuan; Lu Yizhong; Han Dongxue; Zhang Qixian; Niu Li

    2012-01-01

    Ag nanowires are prepared as templates by a polyol reduction process. Then Ag nanotubes coated with a thin layer of Pd are synthesized through sequential reduction accompanied with the galvanic displacement reaction. The products show a hollow core–shell nanotubular structure, as demonstrated by detailed characterizations. The Ag-Pd can significantly improve the electrocatalytic activity towards the electro-oxidation of formic acid and enhance the stability of the Pd component. It is proposed that the enhanced electrochemically active surface area and modulated electron structure of Pd by Ag are responsible for the improvement of electrocatalytic activity and durability. The results obtained in this work are different from those previous reports, in which alloy walls with hollow interiors are usually formed. This work provides a new and simple method for synthesizing novel bimetallic core–shell structure with a hollow interior, which can be applied as high-performance catalysts for the electro-oxidation of formic acid. (paper)

  14. Electrochemical assisted photocatalytic degradation of salicylic acid with highly ordered TiO{sub 2} nanotube electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Qian [The State Key Laboratory of Multiphase Flow in Power Engineering, Xi’an Jiaotong University, Xi’an 710049 (China); Zhu, Jinwei [China Aerospace Science and Technology Corporation Fourty-fourth Research Institution (China); Wang, Ying; Feng, Jiangtao [Department of Environmental Science and Engineering, Xi’an Jiaotong University, Xi’an 710049 (China); Yan, Wei, E-mail: yanwei@mail.xjtu.edu.cn [The State Key Laboratory of Multiphase Flow in Power Engineering, Xi’an Jiaotong University, Xi’an 710049 (China); Department of Environmental Science and Engineering, Xi’an Jiaotong University, Xi’an 710049 (China); Xu, Hao, E-mail: xuhao@mail.xjtu.edu.cn [Department of Environmental Science and Engineering, Xi’an Jiaotong University, Xi’an 710049 (China)

    2014-07-01

    To explore the kinetics of photoelectrocatalytic degradation of salicylic acid, one of the important PPCPs, highly ordered TiO{sub 2} nanotube arrays (NTs) were prepared by the electrochemical anodization and characterized with scanning electron microscopy and X-ray diffraction techniques. The effect of TiO{sub 2} NTs properties, bias potential, initial salicylic acid concentration and solution pH on the degradation efficiency was studied and carefully analyzed. The results revealed that the salicylic acid degradation follows quasi-first order kinetics in the photoelectrocatalytic process, and the fastest decay kinetics was achieved in acidic environment (pH 2). The result was further interpreted through the electrochemical impedance spectroscopy. It is confirmed that the electrochemical assisted photocatalysis is a synergetic approach to combat stable organic substances with improved efficiency.

  15. Novel star-like surfactant as dispersant for multi-walled carbon nanotubes in aqueous suspensions at high concentration

    Science.gov (United States)

    Qiao, Min; Ran, Qianping; Wu, Shishan

    2018-03-01

    A kind of novel surfactant with star-like molecular structure and terminated sulfonate was synthesized, and it was used as the dispersant for multi-walled carbon nanotubes (CNTs) in aqueous suspensions compared with a traditional single-chained surfactant. The star-like surfactant showed good dispersing ability for multi-walled CNTs in aqueous suspensions. Surface tension analysis, total organic carbon analysis, X-ray photoelectron spectroscopy, zeta potential, dynamic light scattering and transmission electron microscopy were performed to research the effect of star-like surfactant on the dispersion of multi-walled CNTs in aqueous suspensions. With the assistance of star-like surfactant, the CNTs could disperse well in aqueous suspension at high concentration of 50 g/L for more than 30 days, while the CNTs precipitated completely in aqueous suspension after 1 day without any dispersant or after 10 days with sodium 4-dodecylbenzenesulfonic acid as dispersant.

  16. Accelerated reliability testing of highly aligned single-walled carbon nanotube networks subjected to DC electrical stressing.

    Science.gov (United States)

    Strus, Mark C; Chiaramonti, Ann N; Kim, Young Lae; Jung, Yung Joon; Keller, Robert R

    2011-07-01

    We investigate the electrical reliability of nanoscale lines of highly aligned, networked, metallic/semiconducting single-walled carbon nanotubes (SWCNTs) fabricated through a template-based fluidic assembly process. We find that these SWCNT networks can withstand DC current densities larger than 10 MA cm(-2) for several hours and, in some cases, several days. We develop test methods that show that the degradation rate, failure predictability and total device lifetime can be linked to the initial resistance. Scanning electron and transmission electron microscopy suggest that fabrication variability plays a critical role in the rate of degradation, and we offer an empirical method of quickly determining the long-term performance of a network. We find that well-fabricated lines subject to constant electrical stress show a linear accumulation of damage reminiscent of electromigration in metallic interconnects, and we explore the underlying physical mechanisms that could cause such behavior.

  17. Bioelectrochemistry of heme peptide at seamless three-dimensional carbon nanotubes/graphene hybrid films for highly sensitive electrochemical biosensing.

    Science.gov (United States)

    Komori, Kikuo; Terse-Thakoor, Trupti; Mulchandani, Ashok

    2015-02-18

    A seamless three-dimensional hybrid film consisting of carbon nanotubes grown at the graphene surface (CNTs/G) is a promising material for the application to highly sensitive enzyme-based electrochemical biosensors. The CNTs/G film was used as a conductive nanoscaffold for enzymes. The heme peptide (HP) was immobilized on the surface of the CNTs/G film for amperometric sensing of H2O2. Compared with flat graphene electrodes modified with HP, the catalytic current for H2O2 reduction at the HP-modified CNTs/G electrode increased due to the increase in the surface coverage of HP. In addition, microvoids in the CNTs/G film contributed to diffusion of H2O2 to modified HP, resulting in the enhancement of the catalytic cathodic currents. The kinetics of the direct electron transfer from the CNTs/G electrode to compound I and II of modified HP was also analyzed.

  18. Highly dispersed Pt-Ni nanoparticles on nitrogen-doped carbon nanotubes for application in direct methanol fuel cells.

    Science.gov (United States)

    Jiang, Shujuan; Ma, Yanwen; Tao, Haisheng; Jian, Guoqiang; Wang, Xizhang; Fan, Yining; Zhu, Jianmin; Hu, Zheng

    2010-06-01

    Binary Pt-Ni alloyed nanoparticles supported on nitrogen-doped carbon nanotubes (NCNTs) have been facilely constructed without pre-modification by making use of the active sites in NCNTs due to the N-participation. So-obtained binary Pt-Ni alloyed nanoparticles have been highly dispersed on the outer surface of the support with the size of about 3-4 nm. The electrochemical properties of the catalysts for methanol oxidation have been systematically evaluated. Binary Pt-Ni alloyed composites with molar ratio (Pt:Ni) of 3:2 and 3:1 present enhanced electrocatalytic activities and improved tolerance to CO poisoning as well as the similar stability, in comparison with the commercial Pt/C catalyst and the monometallic Pt/NCNTs catalysts. These results imply that so-constructed nanocomposite catalysts have the potential for applications in direct methanol fuel cells.

  19. Highly stable palladium-loaded TiO{sub 2} nanotube array electrode for the electrocatalytic hydrodehalogenation of polychlorinated biphenyls

    Energy Technology Data Exchange (ETDEWEB)

    Cui, Chunyue; Wu, Juan; Xin, Yanjun [Qingdao Agricultural University, Qingdao (China); Han, Yanhe [Beijing Institute of Petrochemical Technology, Beijing (China)

    2015-06-15

    Palladized TiO{sub 2} nanotube array electrode was prepared for the electrocatalytic hydrodehalogenation (HDH) of 2,4,5-trichlorobiphenyl (2,4,5-PCB). The TiO{sub 2} nanotube array electrode was successfully fabricated by anodic oxidation method, and Pd was loaded onto the TiO{sub 2} nanotubes by electrochemical deposition. The morphology and structure of the nanotube array electrodes with and without Pd catalysts were evaluated by scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The results showed that the diameters and lengths of the TiO{sub 2} nanotubes were 30-50 nm and 200-400 nm, respectively. The particle size of the Pd was about 12 nm. Electrocatalytic HDH of 2,4,5-PCB with the Pd/TiO{sub 2} nanotube array electrode was performed in H-cell reactor. Under a constant potential of -1.0 V, the HDH efficiency of 2,4,5-PCB was 90% and the biphenyl yield was 83% (15% current efficiency) within 180min at the Pd/TiO{sub 2} nanotube array electrode. Compared with the Pd/Ti electrode, the Pd/TiO{sub 2} nanotube array electrode exhibited higher HDH efficiency and stability. Additionally, the effect of the primary HDH factors was also investigated.

  20. Synthesis and Immobilization of Pt Nanoparticles on Amino-Functionalized Halloysite Nanotubes toward Highly Active Catalysts

    Directory of Open Access Journals (Sweden)

    Tingting Yang

    2015-02-01

    Full Text Available A simple and effective method for the preparation of platinum nanoparticles (Pt NPs grown on amino-func‐ tionalized halloysite nanotubes (HNTs was developed. The nanostructures were synthesized through the func‐ tionalization of the HNTs, followed by an in situ approach to generate Pt NPs with diameter of approximately 1.5 nm within the entire HNTs. The synthesis process, composition and morphology of the nanostructures were characterized. The results suggest PtNPs/NH2-HNTs nanostructures with ultrafine PtNPs were successfully synthesized by green chemically-reducing H2PtCl6 without the use of surfactant. The nanostructures exhibit promising catalytic properties for reducing potassium hexacyanoferrate(III to potassium hexacyanoferrate(II. The presented experiment for novel PtNPs/NH2-HNTs nanostructures is quite simple and environmentally benign, permitting it as a potential application in the future field of catalysts.

  1. High Current Emission from Patterned Aligned Carbon Nanotubes Fabricated by Plasma-Enhanced Chemical Vapor Deposition

    Science.gov (United States)

    Cui, Linfan; Chen, Jiangtao; Yang, Bingjun; Jiao, Tifeng

    2015-12-01

    Vertically, carbon nanotube (CNT) arrays were successfully fabricated on hexagon patterned Si substrates through radio frequency plasma-enhanced chemical vapor deposition using gas mixtures of acetylene (C2H2) and hydrogen (H2) with Fe/Al2O3 catalysts. The CNTs were found to be graphitized with multi-walled structures. Different H2/C2H2 gas flow rate ratio was used to investigate the effect on CNT growth, and the field emission properties were optimized. The CNT emitters exhibited excellent field emission performance (the turn-on and threshold fields were 2.1 and 2.4 V/μm, respectively). The largest emission current could reach 70 mA/cm2. The emission current was stable, and no obvious deterioration was observed during the long-term stability test of 50 h. The results were relevant for practical applications based on CNTs.

  2. Highly conductive, transparent flexible films based on open rings of multi-walled carbon nanotubes

    International Nuclear Information System (INIS)

    Ko, Wen-Yin; Su, Jun-Wei; Guo, Chian-Hua; Fu, Shu-Juan; Hsu, Chuen-Yuan; Lin, Kuan-Jiuh

    2011-01-01

    Open rings of multi-walled carbon nanotubes were stacked to form porous networks on a poly(ethylene terephthalate) substrate to form a flexible conducting film (MWCNT-PET) with good electrical conductivity and transparency by a combination of ultrasonic atomization and spin-coating technique. To enhance the electric flexibility, we spin-coated a cast film of poly(vinyl alcohol) onto the MWCNT-PET substrate, which then underwent a thermo-compression process. Field-emission scanning electron microscopy of the cross-sectional morphology illustrates that the film has a robust network with a thickness of ∼ 175 nm, and it remarkably exhibits a sheet resistance of approximately 370 Ω/sq with ∼ 77% transmittance at 550 nm even after 500 bending cycles. This electrical conductivity is much superior to that of other MWCNT-based transparent flexible films.

  3. Porous carbon nanotube/graphene composites for high-performance supercapacitors

    Science.gov (United States)

    Li, Jing; Tang, Jie; Yuan, Jinshi; Zhang, Kun; Yu, Xiaoliang; Sun, Yige; Zhang, Han; Qin, Lu-Chang

    2018-02-01

    Carbon nanotubes (CNTs) are an effective spacer to prevent the re-stacking of graphene layers. However, the aggregation of CNTs always reduces the specific surface area of resulting CNT/graphene composites. Meanwhile, different pores always have different contributions to the specific capacitance. In this study, CNT/graphene composites with different porous structures are synthesized by co-reduction of oxidized CNTs and graphene oxide with different mixing ratios. With an optimized CNT content of 20%, the CNT/graphene composite shows 206 F g-1 in 1-ethyl-3-methylimidazolium tetrafluoroborate electrolyte. It is found that pores larger than twice the size of electrolyte ions can make greater contributions to the specific capacitance.

  4. Covalently Bonded Graphene-Carbon Nanotube Hybrid for High-Performance Thermal Interfaces

    DEFF Research Database (Denmark)

    Chen, Jie; Walther, Jens H.; Koumoutsakos, Petros

    2015-01-01

    The remarkable thermal properties of graphene and carbon nanotubes (CNTs) have been the subject of intensive investigations for the thermal management of integrated circuits. However, the small contact area of CNTs and the large anisotropic heat conduction of graphene have hindered...... their applications as effective thermal interface materials (TIMs). Here, a covalently bonded graphene–CNT (G-CNT) hybrid is presented that multiplies the axial heat transfer capability of individual CNTs through their parallel arrangement, while at the same time it provides a large contact area for efficient heat...... extraction. Through computer simulations, it is demonstrated that the G-CNT outperforms few-layer graphene by more than 2 orders of magnitude for the c-axis heat transfer, while its thermal resistance is 3 orders of magnitude lower than the state-of-the-art TIMs. We show that heat can be removed from the G...

  5. Nafion Titania Nanotubes Nanocomposite Electrolytes for High-Temperature Direct Methanol Fuel Cells

    Directory of Open Access Journals (Sweden)

    Nonhlanhla Precious Cele

    2012-01-01

    Full Text Available Nafion-based nanocomposite membranes containing various amounts of titania nanotubes (TNTs as an inorganic filler have been prepared using melt-mixing method and have been investigated for proton exchange membrane applications. The one-dimensional TNTs have been prepared from potassium hydroxide using hydrothermal route and conventional heating. Nafion R1100 in a protonated form was used, and TNT contents were in a range of 0.5–2.0 wt%. The acid-treated composite membranes, at lowest inorganic additive content, exhibited improved properties in terms of thermal stability and methanol (MeOH permeability. The best performing nanocomposite was the membrane containing only 0.5 wt% TNTs showing ionic conductivity value of 7.2×10-2 S·cm-1 at 26°C and 100% of relative humidity.

  6. A flexible graphene/multiwalled carbon nanotube film as a high performance electrode material for supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Xiangjun, Lu [College of Material Science and Engineering, Nanjing University of Aeronautics and Astronautics, Yudao Street 29, Nanjing 210016, Jiangsu (China); Dou Hui, E-mail: dh_msc@nuaa.edu.cn [College of Material Science and Engineering, Nanjing University of Aeronautics and Astronautics, Yudao Street 29, Nanjing 210016, Jiangsu (China); Bo, Gao [College of Material Science and Engineering, Nanjing University of Aeronautics and Astronautics, Yudao Street 29, Nanjing 210016, Jiangsu (China); Changzhou, Yuan [School of Materials Science and Engineering, Anhui University of Technology, Maanshan 243002 (China); Yang, Sudong; Liang, Hao; Laifa, Shen [College of Material Science and Engineering, Nanjing University of Aeronautics and Astronautics, Yudao Street 29, Nanjing 210016, Jiangsu (China); Zhang Xiaogang, E-mail: azhangxg@nuaa.edu.cn [College of Material Science and Engineering, Nanjing University of Aeronautics and Astronautics, Yudao Street 29, Nanjing 210016, Jiangsu (China)

    2011-05-30

    Highlights: > A flexible graphene/multiwalled carbon nanotube (GN/MWCNT) film fabricated by flow-directed assembly and hydrazine to reduce. > The MWCNTs in the obtained composite film not only efficiently increase the basal spacing but also bridge the defects for electron transfer between GN sheets. > The freestanding GN/MWCNT film has a potential application in flexible energy storage devices. - Abstract: A flexible graphene/multiwalled carbon nanotube (GN/MWCNT) film has been fabricated by flow-directed assembly from a complex dispersion of graphite oxide (GO) and pristine MWCNTs followed by the use of gas-based hydrazine to reduce the GO into GN sheets. The GN/MWCNT (16 wt.% MWCNTs) film characterized by Fourier transformation infrared spectra, X-ray diffraction and scanning electron microscope has a layered structure with MWCNTs uniformly sandwiched between the GN sheets. The MWCNTs in the obtained composite film not only efficiently increase the basal spacing but also bridge the defects for electron transfer between GN sheets, increasing electrolyte/electrode contact area and facilitating transportation of electrolyte ion and electron into the inner region of electrode. Electrochemical data demonstrate that the GN/MWCNT film possesses a specific capacitance of 265 F g{sup -1} at 0.1 A g{sup -1} and a good rate capability (49% capacity retention at 50 A g{sup -1}), and displays an excellent specific capacitance retention of 97% after 2000 continuous charge/discharge cycles. The results of electrochemical measurements indicate that the freestanding GN/MWCNT film has a potential application in flexible energy storage devices.

  7. A flexible graphene/multiwalled carbon nanotube film as a high performance electrode material for supercapacitors

    International Nuclear Information System (INIS)

    Lu Xiangjun; Dou Hui; Gao Bo; Yuan Changzhou; Yang, Sudong; Hao Liang; Shen Laifa; Zhang Xiaogang

    2011-01-01

    Highlights: → A flexible graphene/multiwalled carbon nanotube (GN/MWCNT) film fabricated by flow-directed assembly and hydrazine to reduce. → The MWCNTs in the obtained composite film not only efficiently increase the basal spacing but also bridge the defects for electron transfer between GN sheets. → The freestanding GN/MWCNT film has a potential application in flexible energy storage devices. - Abstract: A flexible graphene/multiwalled carbon nanotube (GN/MWCNT) film has been fabricated by flow-directed assembly from a complex dispersion of graphite oxide (GO) and pristine MWCNTs followed by the use of gas-based hydrazine to reduce the GO into GN sheets. The GN/MWCNT (16 wt.% MWCNTs) film characterized by Fourier transformation infrared spectra, X-ray diffraction and scanning electron microscope has a layered structure with MWCNTs uniformly sandwiched between the GN sheets. The MWCNTs in the obtained composite film not only efficiently increase the basal spacing but also bridge the defects for electron transfer between GN sheets, increasing electrolyte/electrode contact area and facilitating transportation of electrolyte ion and electron into the inner region of electrode. Electrochemical data demonstrate that the GN/MWCNT film possesses a specific capacitance of 265 F g -1 at 0.1 A g -1 and a good rate capability (49% capacity retention at 50 A g -1 ), and displays an excellent specific capacitance retention of 97% after 2000 continuous charge/discharge cycles. The results of electrochemical measurements indicate that the freestanding GN/MWCNT film has a potential application in flexible energy storage devices.

  8. High adhesion transparent conducting films using graphene oxide hybrid carbon nanotubes

    International Nuclear Information System (INIS)

    Da, Shi-Xun; Wang, Jie; Geng, Hong-Zhang; Jia, Song-Lin; Xu, Chun-Xia; Li, Lin-Ge; Shi, Pei-Pei; Li, Guangfen

    2017-01-01

    Graphical abstract: The GO hybrid CNTs to fabricate TCFs could dramatically enhance the conductivity, adhesion, flatness, and wettability of the films, all these improvements are advantageous for optoelectronic applications. - Highlights: • TCFs were fabricated using GO/CNT hybrid inks by a simple spray method. • Conductivity of TCFs was improved through the hybrid of GO/CNT, sheet resistance of TCFs was 146 Ω/sq at the transmittance of 86.0% when the ratio of GO/CNT got 1.5:1.0. • The flatness and wettability of TCFs were improved dramatically, which is advantageous for the solution-based processing of organic electronics for spraying and printing. • The adhesion of the TCFs increased dramatically with the raise of the ratio GO/CNT hybrid. - Abstract: Flexible transparent conducting films (TCFs) with carbon nanotubes (CNTs) have attracted more and more attention for their wide range of potential applications. While, there are still some problems to be solved on several aspects. In this study, a graphene oxide/carbon nanotube (GO/CNT) hybrid TCF was fabricated through the simple spray coating method. GO sheets were introduced to form new electron transporting channels. It was found that the best optoelectronic property films were fabricated when the ratio of GO/CNT is 1.5:1.0, which the sheet resistance of the film was found to be 146 Ω/sq at the transmittance of 86.0%. Due to the two-dimensional structure and the oxidation groups of GO sheets, flatness and wettability of the electrode surface was improved obviously. Adhesion factor of the TCFs was calculated by the change of transparent and sheet resistance after trial test, the addition of GO sheets enhanced the adhesion dramatically and the mechanism was analyzed. Improvements of conductivity, flatness, wettability and adhesion above are all advantageous for the solution-based processing of organic electronics for spraying and printing.

  9. High adhesion transparent conducting films using graphene oxide hybrid carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Da, Shi-Xun; Wang, Jie; Geng, Hong-Zhang, E-mail: genghz@tjpu.edu.cn; Jia, Song-Lin; Xu, Chun-Xia; Li, Lin-Ge; Shi, Pei-Pei; Li, Guangfen

    2017-01-15

    Graphical abstract: The GO hybrid CNTs to fabricate TCFs could dramatically enhance the conductivity, adhesion, flatness, and wettability of the films, all these improvements are advantageous for optoelectronic applications. - Highlights: • TCFs were fabricated using GO/CNT hybrid inks by a simple spray method. • Conductivity of TCFs was improved through the hybrid of GO/CNT, sheet resistance of TCFs was 146 Ω/sq at the transmittance of 86.0% when the ratio of GO/CNT got 1.5:1.0. • The flatness and wettability of TCFs were improved dramatically, which is advantageous for the solution-based processing of organic electronics for spraying and printing. • The adhesion of the TCFs increased dramatically with the raise of the ratio GO/CNT hybrid. - Abstract: Flexible transparent conducting films (TCFs) with carbon nanotubes (CNTs) have attracted more and more attention for their wide range of potential applications. While, there are still some problems to be solved on several aspects. In this study, a graphene oxide/carbon nanotube (GO/CNT) hybrid TCF was fabricated through the simple spray coating method. GO sheets were introduced to form new electron transporting channels. It was found that the best optoelectronic property films were fabricated when the ratio of GO/CNT is 1.5:1.0, which the sheet resistance of the film was found to be 146 Ω/sq at the transmittance of 86.0%. Due to the two-dimensional structure and the oxidation groups of GO sheets, flatness and wettability of the electrode surface was improved obviously. Adhesion factor of the TCFs was calculated by the change of transparent and sheet resistance after trial test, the addition of GO sheets enhanced the adhesion dramatically and the mechanism was analyzed. Improvements of conductivity, flatness, wettability and adhesion above are all advantageous for the solution-based processing of organic electronics for spraying and printing.

  10. Adhered Supported Carbon Nanotubes

    International Nuclear Information System (INIS)

    Johnson, Dale F.; Craft, Benjamin J.; Jaffe, Stephen M.

    2001-01-01

    Carbon nanotubes (NTs) in excess of 200 μm long are grown by catalytic pyrolysis of hydrocarbon vapors. The nanotubes grow continuously without the typical extinction due to catalyst encapsulation. A woven metal mesh supports the nanotubes creating a metal supported nanotube (MSNT) structure. The 140 μm wide mesh openings are completely filled by 70 nm diameter multiwalled nanotubes (MWNTs). The MWNTs are straight, uniform and highly crystalline. Their wall thickness is about 10 nm (30 graphite layers). The adherent NTs are not removed from the support in a Scotch tape pull test. A 12.5 cm 2 capacitor made from two MSNT structures immersed in 1 M KCl has a capacitance of 0.35 F and an equivalent series resistance of 0.18 Ω. Water flows through the MSNT at a flow velocity of 1 cm/min with a pressure drop of 15 inches of water. With the support removed, the MWNTs naturally form a carbon nanocomposite (CNC) paper with a specific area of 80 m 2 /gm, a bulk density of 0.21 g/cm 3 , an open pore fraction of 0.81, and a resistivity of 0.16 Ω-cm

  11. Ball-milling synthesis of ZnO@sulphur/carbon nanotubes and Ni(OH)_2@sulphur/carbon nanotubes composites for high-performance lithium-sulphur batteries

    International Nuclear Information System (INIS)

    Gu, Xingxing; Tong, Chuan-jia; Wen, Bo; Liu, Li-min; Lai, Chao; Zhang, Shanqing

    2016-01-01

    Highlights: • Metal oxides or hydroxides coating sulfur-based composite are successfully prepared. • Large-scale synthesis can be realized via the facile wet ball-milling strategy. • Density functional theory (DFT) calculation is applied to calculate adsorption energy. • ZnO exhibits a higher adsorption energy for Li_2S_8 than that Ni(OH)_2. • ZnO@sulphur/carbon nanotubes composite show excellent cycle and discharge performance. - Abstract: Zinc oxide wrapped sulphur/carbon nanotubes (ZnO@S/CNT) and nickel hydroxide wrapped sulphur/carbon nanotubes (Ni(OH)_2@S/CNT) nanocomposites are prepared using a simple, low cost and scalable ball-milling method. As the cathodes in Li-S batteries, the as-prepared ZnO@S/CNT composite illustrates a superior high initial capacity of 1663 mAh g"−"1 at a charge/discharge rate of 160 mA g"−"1, and maintains a reversible capacity at approximately 942 mAh g"−"1 after 70 cycles. While for Ni(OH)_2@S/CNT composites, its initial capacity is also as high as 1331 mAh g"−"1, but a poorer cycling stability is presented. When the charge/discharge current is increased to 1600 mA g"−"1, a high reversible capacity of 698 mAh g"−"1 after 200 cycles still can be obtained for the ZnO@S/CNT composite, far better than that of Ni(OH)_2@S/CNT composites. The better cycling performance and high discharge capacity can be attributed to the strong interactions between ZnO and S_x"2"− species, which is verified by the density functional theory (DFT) calculation result that the ZnO exhibits a higher adsorption energy for Li_2S_8 than the Ni(OH)_2.

  12. High-performance and renewable supercapacitors based on TiO2 nanotube array electrodes treated by an electrochemical doping approach

    International Nuclear Information System (INIS)

    Wu, Hui; Li, Dongdong; Zhu, Xufei; Yang, Chunyan; Liu, Dongfang; Chen, Xiaoyuan; Song, Ye; Lu, Linfeng

    2014-01-01

    Although one-dimensional anodic TiO 2 nanotube arrays have shown promise as supercapacitor electrode materials, their poor electronic conductivity embarrasses the practical applications. Here, we develop a simple electrochemical doping method to significantly improve the electronic conductivity and the electrochemical performances of TiO 2 nanotube electrodes. These TiO 2 nanotube electrodes treated by the electrochemical hydrogenation doping (TiO 2 -H) exhibit a very high average specific capacitance of 20.08 mF cm −2 at a current density of 0.05 mA cm −2 , ∼20 times more than the pristine TiO 2 nanotube electrodes. The improved electrochemical performances can be attributed to ultrahigh conductivity of TiO 2 -H due to the introduction of interstitial hydrogen ions and oxygen vacancies by the doping. The supercapacitor device assembled by the doped electrodes delivers a specific capacitance of 5.42 mF cm −2 and power density of 27.66 mW cm −2 , on average, at the current density of 0.05 mA cm −2 . The device also shows an outstanding rate capability with 60% specific capacitance retained when the current density increases from 0.05 to 4.00 mA cm −2 . More interestingly, the electrochemical performances of the supercapacitor after cycling can be recovered by the same doping process. This strategy boosts the performances of the supercapacitor, especially cycling stability

  13. Large-Area High-Performance Flexible Pressure Sensor with Carbon Nanotube Active Matrix for Electronic Skin.

    Science.gov (United States)

    Nela, Luca; Tang, Jianshi; Cao, Qing; Tulevski, George; Han, Shu-Jen

    2018-03-14

    Artificial "electronic skin" is of great interest for mimicking the functionality of human skin, such as tactile pressure sensing. Several important performance metrics include mechanical flexibility, operation voltage, sensitivity, and accuracy, as well as response speed. In this Letter, we demonstrate a large-area high-performance flexible pressure sensor built on an active matrix of 16 × 16 carbon nanotube thin-film transistors (CNT TFTs). Made from highly purified solution tubes, the active matrix exhibits superior flexible TFT performance with high mobility and large current density, along with a high device yield of nearly 99% over 4 inch sample area. The fully integrated flexible pressure sensor operates within a small voltage range of 3 V and shows superb performance featuring high spatial resolution of 4 mm, faster response than human skin (<30 ms), and excellent accuracy in sensing complex objects on both flat and curved surfaces. This work may pave the road for future integration of high-performance electronic skin in smart robotics and prosthetic solutions.

  14. High-Performance Complementary Transistors and Medium-Scale Integrated Circuits Based on Carbon Nanotube Thin Films.

    Science.gov (United States)

    Yang, Yingjun; Ding, Li; Han, Jie; Zhang, Zhiyong; Peng, Lian-Mao

    2017-04-25

    Solution-derived carbon nanotube (CNT) network films with high semiconducting purity are suitable materials for the wafer-scale fabrication of field-effect transistors (FETs) and integrated circuits (ICs). However, it is challenging to realize high-performance complementary metal-oxide semiconductor (CMOS) FETs with high yield and stability on such CNT network films, and this difficulty hinders the development of CNT-film-based ICs. In this work, we developed a doping-free process for the fabrication of CMOS FETs based on solution-processed CNT network films, in which the polarity of the FETs was controlled using Sc or Pd as the source/drain contacts to selectively inject carriers into the channels. The fabricated top-gated CMOS FETs showed high symmetry between the characteristics of n- and p-type devices and exhibited high-performance uniformity and excellent scalability down to a gate length of 1 μm. Many common types of CMOS ICs, including typical logic gates, sequential circuits, and arithmetic units, were constructed based on CNT films, and the fabricated ICs exhibited rail-to-rail outputs because of the high noise margin of CMOS circuits. In particular, 4-bit full adders consisting of 132 CMOS FETs were realized with 100% yield, thereby demonstrating that this CMOS technology shows the potential to advance the development of medium-scale CNT-network-film-based ICs.

  15. Highly reliable field electron emitters produced from reproducible damage-free carbon nanotube composite pastes with optimal inorganic fillers

    Science.gov (United States)

    Kim, Jae-Woo; Jeong, Jin-Woo; Kang, Jun-Tae; Choi, Sungyoul; Ahn, Seungjoon; Song, Yoon-Ho

    2014-02-01

    Highly reliable field electron emitters were developed using a formulation for reproducible damage-free carbon nanotube (CNT) composite pastes with optimal inorganic fillers and a ball-milling method. We carefully controlled the ball-milling sequence and time to avoid any damage to the CNTs, which incorporated fillers that were fully dispersed as paste constituents. The field electron emitters fabricated by printing the CNT pastes were found to exhibit almost perfect adhesion of the CNT emitters to the cathode, along with good uniformity and reproducibility. A high field enhancement factor of around 10 000 was achieved from the CNT field emitters developed. By selecting nano-sized metal alloys and oxides and using the same formulation sequence, we also developed reliable field emitters that could survive high-temperature post processing. These field emitters had high durability to post vacuum annealing at 950 °C, guaranteeing survival of the brazing process used in the sealing of field emission x-ray tubes. We evaluated the field emitters in a triode configuration in the harsh environment of a tiny vacuum-sealed vessel and observed very reliable operation for 30 h at a high current density of 350 mA cm-2. The CNT pastes and related field emitters that were developed could be usefully applied in reliable field emission devices.

  16. High-performance Supercapacitors Based on Electrochemical-induced Vertical-aligned Carbon Nanotubes and Polyaniline Nanocomposite Electrodes

    Science.gov (United States)

    Wu, Guan; Tan, Pengfeng; Wang, Dongxing; Li, Zhe; Peng, Lu; Hu, Ying; Wang, Caifeng; Zhu, Wei; Chen, Su; Chen, Wei

    2017-03-01

    Supercapacitors, which store electrical energy through reversible ion on the surface of conductive electrodes have gained enormous attention for variously portable energy storage devices. Since the capacitive performance is mainly determined by the structural and electrochemical properties of electrodes, the electrodes become more crucial to higher performance. However, due to the disordered microstructure and low electrochemical activity of electrode for ion tortuous migration and accumulation, the supercapacitors present relatively low capacitance and energy density. Here we report a high-performance supercapacitor based on polyaniline/vertical-aligned carbon nanotubes (PANI/VA-CNTs) nanocomposite electrodes where the vertical-aligned-structure is formed by the electrochemical-induction (0.75 V). The supercapacitor displays large specific capacitance of 403.3 F g-1, which is 6 times higher than disordered CNTs in HClO4 electrolyte. Additionally, the supercapacitor can also present high specific capacitance (314.6 F g-1), excellent cycling stability (90.2% retention after 3000 cycles at 4 A g-1) and high energy density (98.1 Wh kg-1) in EMIBF4 organic electrolyte. The key to high-performance lies in the vertical-aligned-structure providing direct path channel for ion faster diffusion and high electrochemical capacitance of polyaniline for ion more accommodation.

  17. High-performance Supercapacitors Based on Electrochemical-induced Vertical-aligned Carbon Nanotubes and Polyaniline Nanocomposite Electrodes.

    Science.gov (United States)

    Wu, Guan; Tan, Pengfeng; Wang, Dongxing; Li, Zhe; Peng, Lu; Hu, Ying; Wang, Caifeng; Zhu, Wei; Chen, Su; Chen, Wei

    2017-03-08

    Supercapacitors, which store electrical energy through reversible ion on the surface of conductive electrodes have gained enormous attention for variously portable energy storage devices. Since the capacitive performance is mainly determined by the structural and electrochemical properties of electrodes, the electrodes become more crucial to higher performance. However, due to the disordered microstructure and low electrochemical activity of electrode for ion tortuous migration and accumulation, the supercapacitors present relatively low capacitance and energy density. Here we report a high-performance supercapacitor based on polyaniline/vertical-aligned carbon nanotubes (PANI/VA-CNTs) nanocomposite electrodes where the vertical-aligned-structure is formed by the electrochemical-induction (0.75 V). The supercapacitor displays large specific capacitance of 403.3 F g -1 , which is 6 times higher than disordered CNTs in HClO 4 electrolyte. Additionally, the supercapacitor can also present high specific capacitance (314.6 F g -1 ), excellent cycling stability (90.2% retention after 3000 cycles at 4 A g -1 ) and high energy density (98.1 Wh kg -1 ) in EMIBF 4 organic electrolyte. The key to high-performance lies in the vertical-aligned-structure providing direct path channel for ion faster diffusion and high electrochemical capacitance of polyaniline for ion more accommodation.

  18. Plasma Treatment of Carbon Nanotubes Applied to Improve the High Performance of Carbon Nanofiber Supercapacitors

    International Nuclear Information System (INIS)

    Chang, Wei-Min; Wang, Cheng-Chien; Chen, Chuh-Yung

    2015-01-01

    Graphical abstract: This article focused on improving conductivity of carbon nanofibers (CNFs) by added plasma-treatment carbon nanotubes (CNTs). The plasma modification method avoided the destruction of the length and structure of the CNTs and maintained their good electrical properties. Through this method, the relation between conductivity and surface activity site of CNFs was investigated. The results shown that he CNTs-MA added to the CNFs successfully maintained the activity sites on the surface of the CNFs and provide a good electric network to enhance the supercapacitor performance of the CNFs. - Highlights: • The plasma modification method avoided the destruction of the length and structure of the CNTs and maintained their good electrical properties. • The highest conductivity of the CNTs-MA/CNF was 5.2 s/cm at 2.5 wt.% of CNTs-MA addition. It was increased to 8.7 time. • The CNTs-MA added to the CNFs successfully maintained the activity sites on the surface of the CNFs and provide a good electric network to enhance the supercapacitor performance of the CNFs. The highest capacitance was 382 F/g. - Abstract: Plasma-treatment carbon nanotubes (CNTs) grafted with maleic anhydride (MA) were embedded in polyacryonitrile nanofibers via electrospinning and subsequently carbonizated at 800 °C to fabricate carbon nanofibers (CNFs). The grafted degree of MA on CNTs (CNTs-MA) was determined via Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The morphology, surface composition and conductivity of the CNTs-MA/CNF were characterized using electron microscopy, X-ray photoelectron and electrochemical impedance spectroscopy, respectively. CNTs-MA not only affected the conductivity of the CNFs but also the types of the nitrogen functional groups that could be represented as active sites on the CNFs to enhance the performance of the supercapacitors. When 2.5 wt.% CNTs-MA was embedded in the CNFs, the highest conductivity was obtained at

  19. Ag2S/CdS/TiO2 Nanotube Array Films with High Photocurrent Density by Spotting Sample Method

    OpenAIRE

    Sun, Hong; Zhao, Peini; Zhang, Fanjun; Liu, Yuliang; Hao, Jingcheng

    2015-01-01

    Ag2S/CdS/TiO2 hybrid nanotube array films (Ag2S/CdS/TNTs) were prepared by selectively depositing a narrow-gap semiconductor—Ag2S (0.9 eV) quantum dots (QDs)—in the local domain of the CdS/TiO2 nanotube array films by spotting sample method (SSM). The improvement of sunlight absorption ability and photocurrent density of titanium dioxide (TiO2) nanotube array films (TNTs) which were obtained by anodic oxidation method was realized because of modifying semiconductor QDs. The CdS/TNTs, Ag2S/TNT...

  20. Nitrogen doped carbon derived from polyimide/multiwall carbon nanotube composites for high performance flexible all-solid-state supercapacitors

    Science.gov (United States)

    Kim, Dae Kyom; Kim, Nam Dong; Park, Seung-Keun; Seong, Kwang-dong; Hwang, Minsik; You, Nam-Ho; Piao, Yuanzhe

    2018-03-01

    Flexible all-solid-state supercapacitors are desirable as potential energy storage systems for wearable technologies. Herein, we synthesize aminophenyl multiwall carbon nanotube (AP-MWCNT) grafted polyimide precursor by in situ polymerization method as a nitrogen-doped carbon precursor. Flexible supercapacitor electrodes are fabricated via a coating of carbon precursor on carbon cloth surface and carbonization at high temperature directly. The as-obtained electrodes, which can be directly used without any binders or additives, can deliver a high specific capacitance of 333.4 F g-1 at 1 A g-1 (based on active material mass) and excellent cycle stability with 103% capacitance retention after 10,000 cycles in a three-electrode system. The flexible all-solid-state supercapacitor device exhibits a high volumetric capacitance of 3.88 F cm-3 at a current density of 0.02 mA cm-3. And also the device can deliver a maximum volumetric energy density of 0.50 mWh cm-3 and presents good cycling stability with 85.3% capacitance retention after 10,000 cycles. This device cell can not only show extraordinary mechanical flexibilities allowing folding, twisting, and rolling but also demonstrate remarkable stable electrochemical performances under their forms. This work provides a novel approach to obtain carbon textile-based flexible supercapacitors with high electrochemical performance and mechanical flexibility.

  1. A monolithic functional film of nanotubes/cellulose/ionic liquid for high performance supercapacitors

    Science.gov (United States)

    Basiricò, Lucia; Lanzara, Giulia

    2014-12-01

    A novel monolithic, pre-fabricated, fully functional film made of a nanostructured free-standing layer is presented for a new and competitive class of easy-to-assemble flexible supercapacitors whose design is in-between the all solid state and the traditional liquid electrolyte. The film is made of two vertically aligned multi-walled carbon nanotube (VANT) electrodes that store ions, embedded-in, and monolithically interspaced by a solution of microcrystalline cellulose in a room temperature ionic liquid (RTIL) electrolyte (1-ethyl-3-methylimidazolium acetate-EMIM Ac). The fine tuning of VANTs length and electrolyte/cellulose amount leads, in a sole and continuous block, to ions storage and physical separation between the electrodes without the need of the additional separator layer that is typically used in supercapacitors. Thus, physical discontinuities that can induce disturbances to ions mobility, are fully eliminated significantly reducing the equivalent series resistance and increasing the knee frequency, hence outclassing the best supercapacitors based on VANTs and non-aqueous electrolytes. The excellent electrochemical response can also be addressed to the chosen electrolyte that, not only has the advantage of leading to a significantly simpler and more affordable fabrication procedure, but has higher ionic conductivity, lower viscosity and higher ions mobility than other electrolytes capable of dissolving cellulose.

  2. Polyaniline modified graphene and carbon nanotube composite electrode for asymmetric supercapacitors of high energy density

    Science.gov (United States)

    Cheng, Qian; Tang, Jie; Shinya, Norio; Qin, Lu-Chang

    2013-11-01

    Graphene and single-walled carbon nanotube (CNT) composites are explored as the electrodes for supercapacitors by coating polyaniline (PANI) nano-cones onto the graphene/CNT composite to obtain graphene/CNT-PANI composite electrode. The graphene/CNT-PANI electrode is assembled with a graphene/CNT electrode into an asymmetric pseudocapacitor and a highest energy density of 188 Wh kg-1 and maximum power density of 200 kW kg-1 are achieved. The structure and morphology of the graphene/CNT composite and the PANI nano-cone coatings are characterized by both scanning electron microscopy and transmission electron microscopy. The excellent performance of the assembled supercapacitors is also discussed and it is attributed to (i) effective utilization of the large surface area of the three-dimensional network structure of graphene-based composite, (ii) the presence of CNT in the composite preventing graphene from re-stacking, and (ii) uniform and vertically aligned PANI coating on graphene offering increased electrical conductivity.

  3. Microwave pumped high-efficient thermoacoustic tumor therapy with single wall carbon nanotubes.

    Science.gov (United States)

    Wen, Liewei; Ding, Wenzheng; Yang, Sihua; Xing, Da

    2016-01-01

    The ultra-short pulse microwave could excite to the strong thermoacoustic (TA) shock wave and deeply penetrate in the biological tissues. Based on this, we developed a novel deep-seated tumor therapy modality with mitochondria-targeting single wall carbon nanotubes (SWNTs) as microwave absorbing agents, which act efficiently to convert ultra-short microwave energy into TA shock wave and selectively destroy the targeted mitochondria, thereby inducing apoptosis in cancer cells. After the treatment of SWNTs (40 μg/mL) and ultra-short microwave (40 Hz, 1 min), 77.5% of cancer cells were killed and the vast majority were caused by apoptosis that initiates from mitochondrial damage. The orthotopic liver cancer mice were established as deep-seated tumor model to investigate the anti-tumor effect of mitochondria-targeting TA therapy. The results suggested that TA therapy could effectively inhibit the tumor growth without any observable side effects, while it was difficult to achieve with photothermal or photoacoustic therapy. These discoveries implied the potential application of TA therapy in deep-seated tumor models and should be further tested for development into a promising therapeutic modality for cancer treatment. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Preparation high photocatalytic activity of CdS/halloysite nanotubes (HNTs) nanocomposites with hydrothermal method

    Science.gov (United States)

    Xing, Weinan; Ni, Liang; Huo, Pengwei; Lu, Ziyang; Liu, Xinlin; Luo, Yingying; Yan, Yongsheng

    2012-10-01

    A novel nanocatalyst CdS/halloysite nanotubes (HNTs) was synthesized by hydrothermal method with direct growth of CdS nanoparticles on the surface of HNTs. The as-prepared photocatalysts had been characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), UV-vis diffuse reflectance spectra (UV-vis DRS), Fourier transform infrared (FT-IR) and the thermo gravimetric analysis (TGA). The photocatalytic activity of the sample was evaluated by the degradation of tetracycline (TC) under visible light irradiation. Benefit from the excellent properties of CdS and HNTs, the photocatalyst exhibited good photocatalytic activity and stability. In order to find out the optimum synthesis condition to obtain the best photocatalytic activity, a series of experiments were performed with different CdS loading capacity, different sources of sulfide and different hydrothermal temperatures, etc. The best photodegradation rate could reach 93% in 60 min under visible light irradiation. Therefore, the combination of CdS nanoparticles with HNTs endowed this material with a potential use in environmental treatments in industries.

  5. Thermal conductivity of high performance carbon nanotube yarn-like fibers

    Energy Technology Data Exchange (ETDEWEB)

    Mayhew, Eric; Prakash, Vikas, E-mail: vikas.prakash@case.edu [Department of Mechanical and Aerospace Engineering, Case Western Reserve University, Cleveland, Ohio 44106-7222 (United States)

    2014-05-07

    In the present paper, we present results of thermal conductivity measurements in free standing carbon nanotube (CNT) yarn-like fibers. The measurements are made using a T-type experimental configuration utilizing a Wollaston-wire hot probe inside a scanning electron microscope. In this technique, a suspended platinum wire is used both as a heater and a thermal sensor. A low frequency alternating current source is used to heat the probe wire while the third harmonic voltage across the wire is measured by a lock-in amplifier. The conductivity is deduced from an analytical model that relates the drop in the spatially averaged temperature of the wire to that of the sample. The average thermal conductivity of the neat CNT fibers and the CNT –polymer composite fibers is found to be 448 W/m-K and 225 W/m-K, respectively. These values for conductivity are amongst the highest measured for CNT yarn-like fibers fabricated using a dry spinning process from vertically aligned CNT arrays. The enhancement in thermal conductivity is understood to be due to an increase in the CNT fiber elastic stiffness during the draw and twist operations, lower CNT thermal contact resistance due to increase in CNT contact area, and better alignment of the CNT fibrils along the length of the fiber.

  6. Highly transparent and conductive thin films fabricated with nano-silver/double-walled carbon nanotube composites.

    Science.gov (United States)

    Lee, Shie-Heng; Teng, Chih-Chun; Ma, Chen-Chi M; Wang, Ikai

    2011-12-01

    This study develops a technique for enhancing the electrical conductivity and optical transmittance of transparent double-walled carbon nanotube (DWNT) film. Silver nanoparticles were modified with a NH(2)(CH(2))(2)SH self-assembled monolayer terminated by amino groups and subsequent surface condensation that reacted with functionalized DWNTs. Ag nanoparticles were grafted on the surface of the DWNTs. The low sheet resistance of the resulting thin conductive film on a polyethylene terephthalate (PET) substrate was due to the increased contact areas between DWNTs and work function by grafting Ag nanoparticles on the DWNT surfaces. Increasing the contact area between DWNTs and work function improved the conductivity of the DWNT-Ag thin films. The prepared DWNT-Ag thin films had a sheet resistance of 53.4 Ω/sq with 90.5% optical transmittance at a 550 nm wavelength. After treatment with HNO(3) and annealing at 150 °C for 30 min, a lower sheet resistance of 45.8 Ω/sq and a higher transmittance of 90.4% could be attained. The value of the DC conductivity to optical conductivity (σ(DC)/σ(OP)) ratio is 121.3. Copyright © 2011 Elsevier Inc. All rights reserved.

  7. A metallization and bonding approach for high performance carbon nanotube thermal interface materials

    International Nuclear Information System (INIS)

    Cross, Robert; Graham, Samuel; Cola, Baratunde A; Fisher, Timothy; Xu Xianfan; Gall, Ken

    2010-01-01

    A method has been developed to create vertically aligned carbon nanotube (VACNT) thermal interface materials that can be attached to a variety of metallized surfaces. VACNT films were grown on Si substrates using standard CVD processing followed by metallization using Ti/Au. The coated CNTs were then bonded to metallized substrates at 220 deg. C. By reducing the adhesion of the VACNTs to the growth substrate during synthesis, the CNTs can be completely transferred from the Si growth substrate and used as a die attachment material for electronic components. Thermal resistance measurements using a photoacoustic technique showed thermal resistances as low as 1.7 mm 2 K W -1 for bonded VACNT films 25-30 μm in length and 10 mm 2 K W -1 for CNTs up to 130 μm in length. Tensile testing demonstrated a die attachment strength of 40 N cm -2 at room temperature. Overall, these metallized and bonded VACNT films demonstrate properties which are promising for next-generation thermal interface material applications.

  8. Silver/carbon nanotube hybrids: A novel conductive network for high-rate lithium ion batteries

    International Nuclear Information System (INIS)

    Zhou, Fangdong; Qiu, Kehui; Peng, Gongchang; Xia, Li

    2015-01-01

    LiNi 1/3 Co 1/3 Mn 1/3 O 2 /Ag composite cathodes are synthesized by a thermal decomposition method and multi-walled carbon nanotubes are uniformly introduced into the composites through ball mixing. A composite electrically conductive network consisting of CNTs and Ag is obtained to improve the conductivity of LiNi 1/3 Co 1/3 Mn 1/3 O 2 material. By comparing with the pure LiNi 1/3 Co 1/3 Mn 1/3 O 2 and cathode modified by CNTs or Ag, the as-obtained LiNi 1/3 Co 1/3 Mn 1/3 O 2 –CNT/Ag electrode exhibits the best rate capability (120.6 mAh/g at 5C) and cycle performance (134.2 mAh/g at 1C with a capacity retention of 94.4% over 100 cycles). With the construction of 3D spatial conductive network, the novel hybrid CNT/Ag demonstrates itself a promising strategy to improve Li storage performance for lithium ion batteries

  9. High photoactive and visible-light responsive graphene/titanate nanotubes photocatalysts: preparation and characterization.

    Science.gov (United States)

    Qianqian, Zhai; Tang, Bo; Guoxin, Hu

    2011-12-30

    A series of graphene/titanate nanotubes (TNTs) photocatalysts using graphene and nanoscale TiO(2) or P25 as original materials were fabricated by hydrothermal method. Both low hydrothermal temperature and proper amount of graphene are propitious to better photoactivity. The photocatalytic activities of these nanocomposites far exceed that of P25, pure TNTs and reported TiO(2)-based nanocomposites for the degradation of Rhodamine-B under visible-light irradiation. These prepared photocatalysts were characterized by TEM, XRD, XPS, BET, FTIR and UV-vis diffuse reflection spectra, and the results indicate that the outstanding photoactivities in visible-light region result from sensitization effect of graphene rather than impurity level in the band gap of TNTs. Furthermore, large BET surface areas of these photocatalysts (almost 10 times larger than that of previously reported graphene/TiO(2) nanoparticles) evidently enhance their absorption abilities and photocatalytic performances (the rate constants of degrading Rhodamine-B are at least 5 times higher than that of previously reported photocatalysts). These photocatalysts show good stability, and their photoactivities do not obviously decrease after four times of repeated uses. A detailed photocatalytic mechanism is suggested, as well. Copyright © 2011 Elsevier B.V. All rights reserved.

  10. Synthesis of carbon-coated TiO 2 nanotubes for high-power lithium-ion batteries

    Science.gov (United States)

    Park, Sang-Jun; Kim, Young-Jun; Lee, Hyukjae

    Carbon-coated TiO 2 nanotubes are prepared by a simple one-step hydrothermal method with an addition of glucose in the starting powder, and are characterized by morphological analysis and electrochemical measurement. A thin carbon coating on the nanotube surface effectively suppresses severe agglomeration of TiO 2 nanotubes during hydrothermal reaction and post calcination. This action results in better ionic and electronic kinetics when applied to lithium-ion batteries. Consequently, carbon-coated TiO 2 nanotubes deliver a remarkable lithium-ion intercalation/deintercalation performance, such as reversible capacities of 286 and 150 mAh g -1 at 250 and 7500 mA g -1, respectively.

  11. When Al-Doped Cobalt Sulfide Nanosheets Meet Nickel Nanotube Arrays: A Highly Efficient and Stable Cathode for Asymmetric Supercapacitors.

    Science.gov (United States)

    Huang, Jun; Wei, Junchao; Xiao, Yingbo; Xu, Yazhou; Xiao, Yujuan; Wang, Ying; Tan, Licheng; Yuan, Kai; Chen, Yiwang

    2018-03-27

    Although cobalt sulfide is a promising electrode material for supercapacitors, its wide application is limited by relative poor electrochemical performance, low electrical conductivity, and inefficient nanostructure. Here, we demonstrated that the electrochemical activity of cobalt sulfide could be significantly improved by Al doping. We designed and fabricated hierarchical core-branch Al-doped cobalt sulfide nanosheets anchored on Ni nanotube arrays combined with carbon cloth (denoted as CC/H-Ni@Al-Co-S) as an excellent self-standing cathode for asymmetric supercapacitors (ASCs). The combination of structural and compositional advantages endows the CC/H-Ni@Al-Co-S electrode with superior electrochemical performance with high specific capacitance (1830 F g -1 /2434 F g -1 at 5 mV s -1 /1 A g -1 ) and excellent rate capability (57.2%/72.3% retention at 1000 mV s -1 /100 A g -1 ). The corresponding all-solid-state ASCs with CC/H-Ni@Al-Co-S and multilayer graphene/CNT film as cathode and anode, respectively, achieve a high energy density up to 65.7 W h kg -1 as well as superb cycling stability (90.6% retention after 10 000 cycles). Moreover, the ASCs also exhibit good flexibility and stability under different bending conditions. This work provides a general, effective route to prepare high-performance electrode materials for flexible all-solid-state energy storage devices.

  12. A facile approach to prepare porous cup-stacked carbon nanotube with high performance in adsorption of methylene blue.

    Science.gov (United States)

    Gong, Jiang; Liu, Jie; Jiang, Zhiwei; Wen, Xin; Mijowska, Ewa; Tang, Tao; Chen, Xuecheng

    2015-05-01

    Novel porous cup-stacked carbon nanotube (P-CSCNT) with special stacked morphology consisting of many truncated conical graphene layers was synthesized by KOH activating CSCNT from polypropylene. The morphology, microstructure, textural property, phase structure, surface element composition and thermal stability of P-CSCNT were investigated by field-emission scanning electron microscope, transmission electron microscope (TEM), high-resolution TEM, N2 sorption, X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy and thermal gravimetric analysis. A part of oblique graphitic layers were etched by KOH, and many holes with a diameter of several to a doze of nanometers connecting inner tube with outside were formed, which endowed P-CSCNT with high specific surface area (558.7 m(2)/g), large pore volume (1.993 cm(3)/g) and abundant surface functional groups. Subsequently, P-CSCNT was used for adsorption of methylene blue (MB) from wastewater. Langmuir model closely fitted the adsorption results, and the maximum adsorption capacity of P-CSCNT was as high as 319.1mg/g. This was ascribed to multiple adsorption mechanisms including pore filling, hydrogen bonding, π-π and electrostatic interactions. Pseudo second-order kinetic model was more valid to describe the adsorption behavior. Besides, P-CSCNT showed good recyclablity and reusability. These results demonstrated that P-CSCNT had potential application in wastewater treatment. Copyright © 2015 Elsevier Inc. All rights reserved.

  13. Cellulose nanofibril/reduced graphene oxide/carbon nanotube hybrid aerogels for highly flexible and all-solid-state supercapacitors.

    Science.gov (United States)

    Zheng, Qifeng; Cai, Zhiyong; Ma, Zhenqiang; Gong, Shaoqin

    2015-02-11

    A novel type of highly flexible and all-solid-state supercapacitor that uses cellulose nanofibril (CNF)/reduced graphene oxide (RGO)/carbon nanotube (CNT) hybrid aerogels as electrodes and H2SO4/poly(vinyl alcohol) (PVA) gel as the electrolyte was developed and is reported here. These flexible solid-state supercapacitors were fabricated without any binders, current collectors, or electroactive additives. Because of the porous structure of the CNF/RGO/CNT aerogel electrodes and the excellent electrolyte absorption properties of the CNFs present in the aerogel electrodes, the resulting flexible supercapacitors exhibited a high specific capacitance (i.e., 252 F g(-1) at a discharge current density of 0.5 A g(-1)) and a remarkable cycle stability (i.e., more than 99.5% of the capacitance was retained after 1000 charge-discharge cycles at a current density of 1 A g(-1)). Furthermore, the supercapacitors also showed extremely high areal capacitance, areal power density, and energy density (i.e., 216 mF cm(-2), 9.5 mW cm(-2), and 28.4 μWh cm(-2), respectively). In light of its excellent electrical performance, low cost, ease of large-scale manufacturing, and environmental friendliness, the CNF/RGO/CNT aerogel electrodes may have a promising application in the development of flexible energy-storage devices.

  14. Heating-Rate-Triggered Carbon-Nanotube-based 3-Dimensional Conducting Networks for a Highly Sensitive Noncontact Sensing Device

    KAUST Repository

    Tai, Yanlong

    2016-01-28

    Recently, flexible and transparent conductive films (TCFs) are drawing more attention for their central role in future applications of flexible electronics. Here, we report the controllable fabrication of TCFs for moisture-sensing applications based on heating-rate-triggered, 3-dimensional porous conducting networks through drop casting lithography of single-walled carbon nanotube (SWCNT)/poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate (PEDOT:PSS) ink. How ink formula and baking conditions influence the self-assembled microstructure of the TCFs is discussed. The sensor presents high-performance properties, including a reasonable sheet resistance (2.1 kohm/sq), a high visible-range transmittance (>69%, PET = 90%), and good stability when subjected to cyclic loading (>1000 cycles, better than indium tin oxide film) during processing, when formulation parameters are well optimized (weight ratio of SWCNT to PEDOT:PSS: 1:0.5, SWCNT concentration: 0.3 mg/ml, and heating rate: 36 °C/minute). Moreover, the benefits of these kinds of TCFs were verified through a fully transparent, highly sensitive, rapid response, noncontact moisture-sensing device (5 × 5 sensing pixels).

  15. Carbon nanotube/metal-sulfide composite flexible electrodes for high-performance quantum dot-sensitized solar cells and supercapacitors.

    Science.gov (United States)

    Muralee Gopi, Chandu V V; Ravi, Seenu; Rao, S Srinivasa; Eswar Reddy, Araveeti; Kim, Hee-Je

    2017-04-19

    Carbon nanotubes (CNT) and metal sulfides have attracted considerable attention owing to their outstanding properties and multiple application areas, such as electrochemical energy conversion and energy storage. Here we describes a cost-effective and facile solution approach to the preparation of metal sulfides (PbS, CuS, CoS, and NiS) grown directly on CNTs, such as CNT/PbS, CNT/CuS, CNT/CoS, and CNT/NiS flexible electrodes for quantum dot-sensitized solar cells (QDSSCs) and supercapacitors (SCs). X-ray photoelectron spectroscopy, X-ray diffraction, and transmission electron microscopy confirmed that the CNT network was covered with high-purity metal sulfide compounds. QDSSCs equipped with the CNT/NiS counter electrode (CE) showed an impressive energy conversion efficiency (η) of 6.41% and remarkable stability. Interestingly, the assembled symmetric CNT/NiS-based polysulfide SC device exhibited a maximal energy density of 35.39 W h kg -1 and superior cycling durability with 98.39% retention after 1,000 cycles compared to the other CNT/metal-sulfides. The elevated performance of the composites was attributed mainly to the good conductivity, high surface area with mesoporous structures and stability of the CNTs and the high electrocatalytic activity of the metal sulfides. Overall, the designed composite CNT/metal-sulfide electrodes offer an important guideline for the development of next level energy conversion and energy storage devices.

  16. Properties of single-walled carbon nanotube-based aerogels as a function of nanotube loading

    International Nuclear Information System (INIS)

    Worsley, Marcus A.; Pauzauskie, Peter J.; Kucheyev, Sergei O.; Zaug, Joseph M.; Hamza, Alex V.; Satcher, Joe H.; Baumann, Theodore F.

    2009-01-01

    Here, we present the synthesis and characterization of low-density single-walled carbon nanotube-based aerogels (SWNT-CA). Aerogels with varying nanotube loading (0-55 wt.%) and density (20-350 mg cm -3 ) were fabricated and characterized by four-probe method, electron microscopy, Raman spectroscopy and nitrogen porosimetry. Several properties of the SWNT-CAs were highly dependent upon nanotube loading. At nanotube loadings of 55 wt.%, shrinkage of the aerogel monoliths during carbonization and drying was almost completely eliminated. Electrical conductivities are improved by an order of magnitude for the SWNT-CA (55 wt.% nanotubes) compared to those of foams without nanotubes. Surface areas as high as 184 m 2 g -1 were achieved for SWNT-CAs with greater than 20 wt.% nanotube loading.

  17. Hybrid membrane using polyethersulfone-modification of multiwalled carbon nanotubes with silane agent to enhance high performance oxygen separation

    Directory of Open Access Journals (Sweden)

    Tutuk Djoko Kusworo

    2014-04-01

    Full Text Available Mixed matrix membrane comprising carbon nanotubes embedded in polymer matrix have become one of the emerging technologies. This study was investigated in order to study the effect of silane agent modification towards carbon nanotubes (CNT surface at different concentration on oxygen enrichment performances of asymmetric mixed matrix membrane. The modified carbon nanotubes were prepared by treating the carbon nanotubes with chemical modification using Dynasylan Ameo (DA silane agent to allow PES chains to be grafted on carbon nanotubes surface. The results from the FESEM, DSC and FTIR analysis confirmed that chemical modification on carbon nanotubes surface had taken place. Sieve-in-a-cage’ morphology observed shows the poor adhesion between polymer and unmodified CNT. The gas separation performance of the asymmetric flat sheet mixed matrix membranes with modified CNT were relatively higher compared to the unmodified CNT. Hence, coated hollow fiber mixed matrix membrane with chemical modification on CNT surface using (3-aminopropyl-triethoxy methyl silane agent can potentially enhance the gas separation performance of O2 and N2.

  18. First-principles study of high-conductance DNA sequencing with carbon nanotube electrodes

    KAUST Repository

    Chen, X.

    2012-03-26

    Rapid and cost-effective DNA sequencing at the single nucleotide level might be achieved by measuring a transverse electronic current as single-stranded DNA is pulled through a nanometer-sized pore. In order to enhance the electronic coupling between the nucleotides and the electrodes and hence the current signals, we employ a pair of single-walled close-ended (6,6) carbon nanotubes (CNTs) as electrodes. We then investigate the electron transport properties of nucleotides sandwiched between such electrodes by using first-principles quantum transport theory. In particular, we consider the extreme case where the separation between the electrodes is the smallest possible that still allows the DNA translocation. The benzene-like ring at the end cap of the CNT can strongly couple with the nucleobases and therefore it can both reduce conformational fluctuations and significantly improve the conductance. As such, when the electrodes are closely spaced, the nucleobases can pass through only with their base plane parallel to the plane of CNT end caps. The optimal molecular configurations, at which the nucleotides strongly couple to the CNTs, and which yield the largest transmission, are first identified. These correspond approximately to the lowest energy configurations. Then the electronic structures and the electron transport of these optimal configurations are analyzed. The typical tunneling currents are of the order of 50 nA for voltages up to 1 V. At higher bias, where resonant transport through the molecular states is possible, the current is of the order of several μA. Below 1 V, the currents associated to the different nucleotides are consistently distinguishable, with adenine having the largest current, guanine the second largest, cytosine the third and, finally, thymine the smallest. We further calculate the transmission coefficient profiles as the nucleotides are dragged along the DNA translocation path and investigate the effects of configurational variations

  19. A highly-deformable composite composed of an entangled network of electrically-conductive carbon-nanotubes embedded in elastic polyurethane

    Czech Academy of Sciences Publication Activity Database

    Slobodian, P.; Říha, Pavel; Sáha, P.

    2012-01-01

    Roč. 50, č. 10 (2012), s. 3446-3453 ISSN 0008-6223 Grant - others:OP VaVpI(XE) CZ.1.05/2.1.00/03.0111 Institutional research plan: CEZ:AV0Z20600510 Keywords : carbon nanotubes * polyurethane * high deformation * strain sensor * resistance * biomechanics Subject RIV: JB - Sensor s, Measurment, Regulation Impact factor: 5.868, year: 2012

  20. A highly-deformable composite composed of an entangled network of electrically-conductive carbon-nanotubes embedded in elastic polyurethane

    Czech Academy of Sciences Publication Activity Database

    Slobodian, P.; Říha, Pavel; Sáha, P.

    2012-01-01

    Roč. 50, č. 10 (2012), s. 3446-3453 ISSN 0008-6223 Grant - others:OP VaVpI(XE) CZ.1.05/2.1.00/03.0111 Institutional research plan: CEZ:AV0Z20600510 Keywords : carbon nanotubes * polyurethane * high deformation * strain sensor * resistance * biomechanics Subject RIV: JB - Sensors, Measurment, Regulation Impact factor: 5.868, year: 2012

  1. CoFe2O4/carbon nanotube aerogels as high performance anodes for lithium ion batteries

    Directory of Open Access Journals (Sweden)

    Xin Sun

    2017-04-01

    Full Text Available High-performance lithium ion batteries (LIBs require electrode material to have an ideal electrode construction which provides fast ion transport, short solid-state ion diffusion, large surface area, and high electric conductivity. Herein, highly porous three-dimensional (3D aerogels composed of cobalt ferrite (CoFe2O4, CFO nanoparticles (NPs and carbon nanotubes (CNTs are prepared using sustainable alginate as the precursor. The key feature of this work is that by using the characteristic egg-box structure of the alginate, metal cations such as Co2+ and Fe3+ can be easily chelated via an ion-exchange process, thus binary CFO are expected to be prepared. In the hybrid aerogels, CFO NPs interconnected by the CNTs are embedded in carbon aerogel matrix, forming the 3D network which can provide high surface area, buffer the volume expansion and offer efficient ion and electron transport pathways for achieving high performance LIBs. The as-prepared hybrid aerogels with the optimum CNT content (20 wt% delivers excellent electrochemical properties, i.e., reversible capacity of 1033 mAh g−1 at 0.1 A g−1 and a high specific capacity of 874 mAh g−1 after 160 cycles at 1 A g−1. This work provides a facile and low cost route to fabricate high performance anodes for LIBs. Keywords: Alginate, Aerogels, Cobalt ferrite, Anode, Lithium-ion battery

  2. Stannous sulfide/multi-walled carbon nanotube hybrids as high-performance anode materials of lithium-ion batteries

    International Nuclear Information System (INIS)

    Li, Shuankui; Zuo, Shiyong; Wu, Zhiguo; Liu, Ying; Zhuo, Renfu; Feng, Juanjuan; Yan, De; Wang, Jun; Yan, Pengxun

    2014-01-01

    A hybrid of multi-walled carbon nanotubes (MWCNTs) anchored with SnS nanosheets is synthesized through a simple solvothermal method for the first time. Interestingly, SnS can be controllably deposited onto the MWCNTs backbone in the shape of nanosheets or nanoparticles to form two types of SnS/MWCNTs hybrids, SnS NSs/MWCNTs and SnS NPs/MWCNTs. When evaluated as an anode material for lithium-ion batteries, the hybrids exhibit higher lithium storage capacities and better cycling performance compared to pure SnS. It is found that the SnS NSs/MWCNTs hybrid exhibits a large reversible capacity of 620mAhg −1 at a current of 100mAg −1 as an anode material for lithium-ion batteries, which is better than SnS NPs/MWCNTs. The improved performance may be attributed to the ultrathin nanosheet subunits possess short distance for Li + ions diffusion and large electrode-electrolyte contact area for high Li + ions flux across the interface. It is believed that the structural design of electrodes demonstrated in this work will have important implications on the fabrication of high-performance electrode materials for lithium-ion batteries

  3. Electrical and Self-Sensing Properties of Ultra-High-Performance Fiber-Reinforced Concrete with Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Ilhwan You

    2017-10-01

    Full Text Available This study examined the electrical and self-sensing capacities of ultra-high-performance fiber-reinforced concrete (UHPFRC with and without carbon nanotubes (CNTs. For this, the effects of steel fiber content, orientation, and pore water content on the electrical and piezoresistive properties of UHPFRC without CNTs were first evaluated. Then, the effect of CNT content on the self-sensing capacities of UHPFRC under compression and flexure was investigated. Test results indicated that higher steel fiber content, better fiber orientation, and higher amount of pore water led to higher electrical conductivity of UHPFRC. The effects of fiber orientation and drying condition on the electrical conductivity became minor as sufficiently high amount of steel fibers, 3% by volume, was added. Including only steel fibers did not impart UHPFRC with piezoresistive properties. Addition of CNTs substantially improved the electrical conductivity of UHPFRC. Under compression, UHPFRC with a CNT content of 0.3% or greater had a self-sensing ability that was activated by the formation of cracks, and better sensing capacity was achieved by including greater amount of CNTs. Furthermore, the pre-peak flexural behavior of UHPFRC was precisely simulated with a fractional change in resistivity when 0.3% CNTs were incorporated. The pre-cracking self-sensing capacity of UHPFRC with CNTs was more effective under tensile stress state than under compressive stress state.

  4. Special structures and properties of hydrogen nanowire confined in a single walled carbon nanotube at extreme high pressure

    Directory of Open Access Journals (Sweden)

    Yueyuan Xia

    2012-06-01

    Full Text Available Extensive ab initio molecular dynamics simulations indicate that hydrogen can be confined in single walled carbon nanotubes to form high density and high pressure H2 molecular lattice, which has peculiar shell and axial structures depending on the density or pressure. The band gap of the confined H2 lattice is sensitive to the pressure. Heating the system at 2000K, the H2 lattice is firstly melted to form H2 molecular liquid, and then some of the H2 molecules dissociate accompanied by drastic molecular and atomic reactions, which have essential effect on the electronic structure of the hydrogen system. The liquid hydrogen system at 2000K is found to be a particular mixed liquid, which consists of H2 molecules, H atoms, and H-H-H trimers. The dissociated H atoms and the trimers in the liquid contribute resonance electron states at the Fermi energy to change the material properties substantially. Rapidly cooling the system from 2000K to 0.01 K, the mixed liquid is frozen to form a mixed solid melt with a clear trend of band gap closure. It indicates that this solid melt may become a superconducting nanowire when it is further compressed.

  5. Symmetrical MnO2-carbon nanotube-textile nanostructures for wearable pseudocapacitors with high mass loading

    KAUST Repository

    Hu, Liangbing; Chen, Wei; Xie, Xing; Liu, Nian; Yang, Yuan; Wu, Hui; Yao, Yan; Pasta, Mauro; Alshareef, Husam N.; Cui, Yi

    2011-01-01

    While MnO2 is a promising material for pseudocapacitor applications due to its high specific capacity and low cost, MnO2 electrodes suffer from their low electrical and ionic conductivities. In this article, we report a structure where MnO2 nanoflowers were conformally electrodeposited onto carbon nanotube (CNT)-enabled conductive textile fibers. Such nanostructures effectively decrease the ion diffusion and charge transport resistance in the electrode. For a given areal mass loading, the thickness of MnO2 on conductive textile fibers is much smaller than that on a flat metal substrate. Such a porous structure also allows a large mass loading, up to 8.3 mg/cm2, which leads to a high areal capacitance of 2.8 F/cm2 at a scan rate of 0.05 mV/s. Full cells were demonstrated, where the MnO2-CNT-textile was used as a positive electrode, reduced MnO2-CNT-textile as a negative electrode, and 0.5 M Na2SO4 in water as the electrolyte. The resulting pseudocapacitor shows promising results as a low-cost energy storage solution and an attractive wearable power. © 2011 American Chemical Society.

  6. Highly selective electrodeposition of sub-10 nm crystalline noble metallic nanorods inside vertically aligned multiwall carbon nanotubes

    Science.gov (United States)

    Wang, Xuyang; Wang, Ranran; Wu, Qiang; Zhang, Xiaohua; Yang, Zhaohui; Guo, Jun; Chen, Muzi; Tang, Minghua; Cheng, Yajun; Chu, Haibin

    2016-07-01

    In this paper crystalline noble metallic nanorods including Au and Ag with sub-10 nm diameter, are encapsulated within prealigned and open-ended multiwall carbon nanotubes (MWCNTs) through an electrodeposition method. As the external surface of CNTs has been insulated by the epoxy the CNT channel becomes the only path for the mass transport as well as the nanoreactor for the metal deposition. Highly crystallized Au and Ag2O nanorods parallel to the radial direction of CNTs are confirmed by high-resolution transmission electron microscopy, energy dispersive x-ray spectroscopy and x-ray powder diffraction spectroscopy. The Ag2O nanorods are formed by air oxidation on the Ag metals and show a single crystalline structure with (111) planes. The Au nanorods exhibit a complex crystalline structure including twin-crystal and lattice dislocation with (111) and (200) planes. These crystalline noble metallic nanostructures may have important applications for nanocatalysts for fuel cells as well as nanoelectronic and nanophotonic devices. This method is deemed to benefit the precise deposition of other crystalline nanostructures inside CNTs with a small diameter.

  7. Influence of high-energy electron irradiation on field emission properties of multi-walled carbon nanotubes (MWCNTs) films

    Energy Technology Data Exchange (ETDEWEB)

    Patil, Sandip S. [Center for Advanced Studies in Material Science and Condensed Matter Physics, Department of Physics, University of Pune, Pune 411007 (India); Koinkar, Pankaj M. [Center for International Cooperation in Engineering Education (CICEE), University of Tokushima, 2-1 Minami-Josanjima-Cho, Tokushima 770-8506 (Japan); Dhole, Sanjay D. [Center for Advanced Studies in Material Science and Condensed Matter Physics, Department of Physics, University of Pune, Pune 411007 (India); More, Mahendra A., E-mail: mam@physics.unipune.ac.i [Center for Advanced Studies in Material Science and Condensed Matter Physics, Department of Physics, University of Pune, Pune 411007 (India); Murakami, Ri-ichi, E-mail: murakami@me.tokushima-u.ac.j [Department of Mechanical Engineering, University of Tokushima, 2-1 Minami-Josanjima-Cho, Tokushima 770-8506 (Japan)

    2011-04-15

    The effect of very high energy electron beam irradiation on the field emission characteristics of multi-walled carbon nanotubes (MWCNTs) has been investigated. The MWCNTs films deposited on silicon (Si) substrates were irradiated with 6 MeV electron beam at different fluence of 1x10{sup 15}, 2x10{sup 15} and 3x10{sup 15} electrons/cm{sup 2}. The irradiated films were characterized using scanning electron microscope (SEM) and micro-Raman spectrometer. The SEM analysis clearly revealed a change in surface morphology of the films upon irradiation. The Raman spectra of the irradiated films show structural damage caused by the interaction of high-energy electrons. The field emission studies were carried out in a planar diode configuration at the base pressure of {approx}1x10{sup -8} mbar. The values of the threshold field, required to draw an emission current density of {approx}1 {mu}A/cm{sup 2}, are found to be {approx}0.52, 1.9, 1.3 and 0.8 V/{mu}m for untreated, irradiated with fluence of 1x10{sup 15}, 2x10{sup 15} and 3x10{sup 15} electrons/cm{sup 2}. The irradiated films exhibit better emission current stability as compared to the untreated film. The improved field emission properties of the irradiated films have been attributed to the structural damage as revealed from the Raman studies.

  8. Flexible Transparent Films Based on Nanocomposite Networks of Polyaniline and Carbon Nanotubes for High-Performance Gas Sensing.

    Science.gov (United States)

    Wan, Pengbo; Wen, Xuemei; Sun, Chaozheng; Chandran, Bevita K; Zhang, Han; Sun, Xiaoming; Chen, Xiaodong

    2015-10-28

    A flexible, transparent, chemical gas sensor is assembled from a transparent conducting film of carbon nanotube (CNT) networks that are coated with hierarchically nanostructured polyaniline (PANI) nanorods. The nanocomposite film is synthesized by in-situ, chemical oxidative polymerization of aniline in a functional multiwalled CNT (FMWCNT) suspension and is simultaneously deposited onto a flexible polyethylene terephthalate (PET) substrate. An as-prepared flexible transparent chemical gas sensor exhibits excellent transparency of 85.0% at 550 nm using the PANI/FMWCNT nanocomposite film prepared over a reaction time of 8 h. The sensor also shows good flexibility, without any obvious decrease in performance after 500 bending/extending cycles, demonstrating high-performance, portable gas sensing at room temperature. This superior performance could be attributed to the improved electron transport and collection due to the CNTs, resulting in reliable and efficient sensing, as well as the high surface-to-volume ratio of the hierarchically nanostructured composites. The excellent transparency, improved sensing performance, and superior flexibility of the device, may enable the integration of this simple, low-cost, gas sensor into handheld flexible transparent electronic circuitry and optoelectronic devices. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Nanodiamond decorated liposomes as highly biocompatible delivery vehicles and a comparison with carbon nanotubes and graphene oxide.

    Science.gov (United States)

    Wang, Feng; Liu, Juewen

    2013-12-21

    Studying interactions between nano-carbons and lipid membranes is important for multiplexed drug delivery, device fabrication and for understanding toxicity. Herein, we report that nanodiamond (ND, sp(3) carbon) forms a complex with highly biocompatible zwitterionic liposomes based on hydrogen bonding, which is confirmed by pH-dependent and urea-dependent assays. Despite such weak interaction, the complex is highly stable. Comparisons were made with two sp(2) carbons: nanoscale graphene oxide (NGO) and carbon nanotubes (CNTs), where CNT adsorption is the weakest. Adsorption of the nano-carbons does not induce liposome leakage or affect lipid phase transition temperature. Therefore, the potential toxicity of nano-carbons is unlikely to be related to direct membrane damage. ND facilitates cellular uptake of liposomes and co-delivery of negatively charged calcein and positively charged doxorubicin has been demonstrated. ND has the lowest toxicity, while CNTs and NGO are slightly more toxic. The effect of introducing fusogenic lipids and cholesterol was further studied to understand the effect of lipid formulation.

  10. Symmetrical MnO2-carbon nanotube-textile nanostructures for wearable pseudocapacitors with high mass loading

    KAUST Repository

    Hu, Liangbing

    2011-11-22

    While MnO2 is a promising material for pseudocapacitor applications due to its high specific capacity and low cost, MnO2 electrodes suffer from their low electrical and ionic conductivities. In this article, we report a structure where MnO2 nanoflowers were conformally electrodeposited onto carbon nanotube (CNT)-enabled conductive textile fibers. Such nanostructures effectively decrease the ion diffusion and charge transport resistance in the electrode. For a given areal mass loading, the thickness of MnO2 on conductive textile fibers is much smaller than that on a flat metal substrate. Such a porous structure also allows a large mass loading, up to 8.3 mg/cm2, which leads to a high areal capacitance of 2.8 F/cm2 at a scan rate of 0.05 mV/s. Full cells were demonstrated, where the MnO2-CNT-textile was used as a positive electrode, reduced MnO2-CNT-textile as a negative electrode, and 0.5 M Na2SO4 in water as the electrolyte. The resulting pseudocapacitor shows promising results as a low-cost energy storage solution and an attractive wearable power. © 2011 American Chemical Society.

  11. Self-supporting activated carbon/carbon nanotube/reduced graphene oxide flexible electrode for high performance supercapacitor

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xing; Tang, Yao; Song, Junhua; Yang, Wei; Wang, Mingshan; Zhu, Chengzhou; Zhao, Wengao; Zheng, Jianming; Lin, Yuehe

    2018-04-30

    A self-supporting and flexible activated carbon/carbon nanotube/reduced graphene oxide (AC/CNT/RGO) film has been rationally designed for constructing high- performance supercapacitor. The AC/CNT/RGO film is prepared by anchoring the AC particles with a 3D and porous framework built by hierarchically weaving the 1 D CNT and 2D RGO using their intrinsic van der Waals force. The CNT network is beneficial for improving the electronic conductivity of the electrode, while the AC particles could effectively suppress the aggregation of RGO and CNT due to their blocking effect. The synergistic effects among the AC, CNT and RGO validate the AC/CNT/RGO as a promising electrode for supercapacitor, exhibiting greatly enhanced electrochemical performances in comparison with the pure RGO film, pure CNT film and AC electrode. The AC/CNT/RGO electrode delivers a high specific capacitance of 101 F g-1 at the current density of 0.2 A g-1, offering a maximum energy density of 30.0 W h kg-1 in organic electrolyte at the cut-off voltage range of 0.001~3.0 V. The findings of this work open a new avenue for the design of self-supporting electrodes for the development of flexible and light weight energy storage supercapacitor.

  12. Electrical and Self-Sensing Properties of Ultra-High-Performance Fiber-Reinforced Concrete with Carbon Nanotubes.

    Science.gov (United States)

    You, Ilhwan; Yoo, Doo-Yeol; Kim, Sooho; Kim, Min-Jae; Zi, Goangseup

    2017-10-29

    This study examined the electrical and self-sensing capacities of ultra-high-performance fiber-reinforced concrete (UHPFRC) with and without carbon nanotubes (CNTs). For this, the effects of steel fiber content, orientation, and pore water content on the electrical and piezoresistive properties of UHPFRC without CNTs were first evaluated. Then, the effect of CNT content on the self-sensing capacities of UHPFRC under compression and flexure was investigated. Test results indicated that higher steel fiber content, better fiber orientation, and higher amount of pore water led to higher electrical conductivity of UHPFRC. The effects of fiber orientation and drying condition on the electrical conductivity became minor as sufficiently high amount of steel fibers, 3% by volume, was added. Including only steel fibers did not impart UHPFRC with piezoresistive properties. Addition of CNTs substantially improved the electrical conductivity of UHPFRC. Under compression, UHPFRC with a CNT content of 0.3% or greater had a self-sensing ability that was activated by the formation of cracks, and better sensing capacity was achieved by including greater amount of CNTs. Furthermore, the pre-peak flexural behavior of UHPFRC was precisely simulated with a fractional change in resistivity when 0.3% CNTs were incorporated. The pre-cracking self-sensing capacity of UHPFRC with CNTs was more effective under tensile stress state than under compressive stress state.

  13. Morphological control of three-dimensional carbon nanotube anode for high-capacity lithium-ion battery

    Science.gov (United States)

    Kang, Chiwon; Lee, Hoo-Jeong

    2018-05-01

    In this paper, we report the results of modulating the processing conditions (mainly, temperature) of a two-step method consisting of sputtering deposition of a Ni catalytic layer and chemical vapor deposition (CVD) of carbon nanotubes (CNTs) on a three-dimensional (3D)-structured Cu mesh to control the morphology of CNTs for advanced Li-ion battery (LIB) applications. We disclosed that CNT growth at a low temperature (700 °C) produced small-diameter CNTs (CNT_S) with an average diameter of ∼20 nm, while that at a high temperature (750 °C) produced large-diameter CNTs (CNT_L) with an average diameter of 200–300 nm. The high-resolution transmission electron microscopy (HR-TEM) and Raman analyses manifested poorly crystalline CNTs for both samples. CNTS showed a specific capacity of 476 mAh g‑1, which is ∼176% superior to that of CNTL (271 mAh g‑1) and ∼128% higher than the theoretical capacity of the state-of-the-art graphites and recently reported nanostructured carbon-based anode materials.

  14. Constructing Dense SiO x @Carbon Nanotubes versus Spinel Cathode for Advanced High-Energy Lithium-Ion Batteries

    KAUST Repository

    Ming, Hai

    2017-02-09

    A newly designed dense SiOx@carbon nanotubes (CNTs) composite with a high conductivity of 3.5 S cm−1 and tap density of 1.13 g cm−3 was prepared, in which the CNTs were stripped by physical energy crushing and then coated on SiOx nanoparticles. The composite exhibits high capacities of 835 and 687 mAh g−1 at current densities of 100 and 200 mA g−1, which can be finely persevered over 100 cycles. Benefiting from this promising anode, two new full cells of SiOx@CNTs/LiMn2O4 and SiOx@CNTs/LiNi0.5Mn1.5O4 with high energy densities of 2273 and 2747 Wh kganode−1 (i. e. 413 and 500 Wh kgcathode−1), respectively, were successfully assembled and can cycle more than 400 cycles. Even with further cycling at the elevated temperature of 45 °C, the cells can still deliver relatively high capacities of 568 and 465 mAh ganode−1, respectively, over 100 cycles. Such desired high-energy lithium-ion batteries with working voltages over 4.0 V can be widely developed for diverse applications (e. g. in handheld devices, electric vehicles, and hybrid electric vehicles). The easy extension of the presented synthetic strategy and the configuration of high-energy battery system would be significant in materials synthesis and energy-storage devices.

  15. High-performance thin-film-transistors based on semiconducting-enriched single-walled carbon nanotubes processed by electrical-breakdown strategy

    Energy Technology Data Exchange (ETDEWEB)

    Aïssa, B., E-mail: aissab@emt.inrs.ca [Centre Énergie, Matériaux et Télécommunications, INRS, 1650, boulevard Lionel-Boulet, Varennes, Quebec J3X 1S2 (Canada); Qatar Environment and Energy Research Institute (QEERI), Qatar Foundation, P.O. Box 5825, Doha (Qatar); Nedil, M. [Telebec Wireless Underground Communication Laboratory, UQAT, 675, 1" è" r" e Avenue, Val d’Or, Québec J9P 1Y3 (Canada); Habib, M.A. [Computer Sciences and Engineering Department, Yanbu University College, P.O. Box 30031 (Saudi Arabia); Abdul-Hafidh, E.H. [High Energy Physics Department, Yanbu University College, P.O. Box 30031 (Saudi Arabia); Rosei, F. [Centre Énergie, Matériaux et Télécommunications, INRS, 1650, boulevard Lionel-Boulet, Varennes, Quebec J3X 1S2 (Canada)

    2015-02-15

    Highlights: • We selectively burn metallic single wall carbon nanotubes (SWCNT) by electrical breakdown. • We successfully achieve a semiconducting enriched-SWCNT in TFT configuration. • High performance, like On/Off of 10{sup 5} and a subthreshold swing of 165 mV/decades were obtained. • After PMMA coating, the SWCNT–TFTs were found stables for more than 4 months. - Abstract: Over the past two decades, among remarkable variety of nanomaterials, single-walled carbon nanotubes (SWCNTs) remain the most intriguing and uniquely well suited materials for applications in high-performance electronics. The most advanced technologies require the ability to form purely semiconducting SWCNTs. Here, we report on our strategy based on the well known progressive electrical breakdown process that offer this capability and serves as highly efficient means for selectively removing metallic carbon nanotubes from electronically heterogeneous random networks, deposited on silicon substrates in a thin film transistor (TFT) configuration. We demonstrate the successful achievement of semiconducting enriched-SWCNT networks in TFT scheme that reach On/Off switching ratios of ∼100,000, on-conductance of 20 μS, and a subthreshold swing of less than 165 mV/decades. The obtained TFT devices were then protected with thin film poly(methyl methacrylate) (PMMA) to keep the percolation level of the SWCNTs network spatially and temporally stable, while protecting it from atmosphere exchanges. TFT devices were found to be air-stable and maintained their excellent characteristics in ambient atmosphere for more than 4 months. This approach could work as a platform for future nanotube-based nanoelectronics.

  16. 3D NANOTUBE FIELD EFFECT TRANSISTORS FOR HYBRID HIGH-PERFORMANCE AND LOW-POWER OPERATION WITH HIGH CHIP-AREA EFFICIENCY

    KAUST Repository

    Fahad, Hossain M.

    2014-03-01

    scaling on silicon, the amount of current generated per device has to be increased while keeping short channel effects and off-state leakage at bay. The objective of this doctoral thesis is the investigation of an innovative vertical silicon based architecture called the silicon nanotube field effect transistor (Si NTFET). This topology incorporates a dual inner/outer core/shell gate stack strategy to control the volume inversion properties in a hollow silicon 1D quasi-nanotube under a tight electrostatic configuration. Together with vertically aligned source and drain, the Si NTFET is capable of very high on-state performance (drive current) in an area-efficient configuration as opposed to arrays of gate-all-around nanowires, while maintaining leakage characteristics similar to a single nanowire. Such a device architecture offsets the need of device arraying that is needed with fin and nanowire architectures. Extensive simulations are used to validate the potential benefits of Si NTFETs over GAA NWFETs on a variety of platforms such as conventional MOSFETs, tunnel FETs, junction-less FETs. This thesis demonstrates a novel CMOS compatible process flow to fabricate vertical nanotube transistors that offer a variety of advantages such as lithography-independent gate length definition, integration of epitaxially grown silicon nanotubes with spacer based gate dielectrics and abrupt in-situ doped source/drain junctions. Experimental measurement data will showcase the various materials and processing challenges in fabricating these devices. Finally, an extension of this work to topologically transformed wavy channel FinFETs is also demonstrated keeping in line with the theme of area efficient high-performance electronics.

  17. Use of alkali metal salts to prepare high purity single-walled carbon nanotube solutions and thin films

    Science.gov (United States)

    Ashour, Rakan F.

    Single-walled carbon nanotubes (SWCNTs) display interesting electronic and optical properties desired for many advanced thin film applications, such as transparent conductive electrodes or thin-film transistors. Large-scale production of SWCNTs generally results in polydispersed mixtures of nanotube structures. Since SWCNT electronic character (conducting or semiconducting nature) depends on the nanotube structure, application performance is being held back by this inability to discretely control SWCNT synthesis. Although a number of post-production techniques are able to separate SWCNTs based on electronic character, diameter, or chirality, most still suffer from the disadvantage of high costs of materials, equipment, or labor intensity to be relevant for large-scale production. On the other hand, chromatographic separation has emerged as a method that is compatible with large scale separation of metallic and semiconducting SWCNTs. In this work, SWCNTs, in an aqueous surfactant suspension of sodium dodecyl sulfate (SDS), are separated by their electronic character using a gel chromatography process. Metallic SWCNTs (m-SWCNTs) are collected as initial fractions since they show minimum interaction with the gel medium, whereas, semiconducting SWCNTs (sc- SWCNTs) remain adsorbed to the gel. The process of sc-SWCNT retention in the gel is found to be driven by the packing density of SDS around the SWCNTs. Through a series of separation experiments, it is shown that sc-SWCNTs can be eluted from the gel simply by disturbing the configuration of the SDS/SWCNT micellar structure. This is achieved by either introducing a solution containing a co-surfactant, such as sodium cholate (SC), or solutions of alkali metal ionic salts. Analysis of SWCNT suspensions by optical absorption provides insights into the effect of changing the metal ion (M+ = Li+, Na+, and K+) in the eluting solution. Salts with smaller metal ions (e.g. Li+) require higher concentrations to achieve

  18. Gold(I)-Alkanethiolate Nanotubes

    KAUST Repository

    Zhang, Yu Xin; Zeng, Hua Chun

    2009-01-01

    (Figure Presented) A solution approach to assembling Au(I) - alkanethiolates into nanotube structures at room temperature is presented, in which Au(I) cations and alkanethiolate ligands are coordinated into thin platelet forms that then evolve into an open tubular configuration (see figure). The organic-inorganic hybrid nature of the nanotubes, their ability to be modified, and their high stability make them of interest for practical applications. © 2009 WILEY-VCH Verlag GmbH & Co. KGaA.

  19. Gold(I)-Alkanethiolate Nanotubes

    KAUST Repository

    Zhang, Yu Xin

    2009-12-28

    (Figure Presented) A solution approach to assembling Au(I) - alkanethiolates into nanotube structures at room temperature is presented, in which Au(I) cations and alkanethiolate ligands are coordinated into thin platelet forms that then evolve into an open tubular configuration (see figure). The organic-inorganic hybrid nature of the nanotubes, their ability to be modified, and their high stability make them of interest for practical applications. © 2009 WILEY-VCH Verlag GmbH & Co. KGaA.

  20. Thermally Stable and Electrically Conductive, Vertically Aligned Carbon Nanotube/Silicon Infiltrated Composite Structures for High-Temperature Electrodes.

    Science.gov (United States)

    Zou, Qi Ming; Deng, Lei Min; Li, Da Wei; Zhou, Yun Shen; Golgir, Hossein Rabiee; Keramatnejad, Kamran; Fan, Li Sha; Jiang, Lan; Silvain, Jean-Francois; Lu, Yong Feng

    2017-10-25

    Traditional ceramic-based, high-temperature electrode materials (e.g., lanthanum chromate) are severely limited due to their conditional electrical conductivity and poor stability under harsh circumstances. Advanced composite structures based on vertically aligned carbon nanotubes (VACNTs) and high-temperature ceramics are expected to address this grand challenge, in which ceramic serves as a shielding layer protecting the VACNTs from the oxidation and erosive environment, while the VACNTs work as a conductor. However, it is still a great challenge to fabricate VACNT/ceramic composite structures due to the limited diffusion of ceramics inside the VACNT arrays. In this work, we report on the controllable fabrication of infiltrated (and noninfiltrated) VACNT/silicon composite structures via thermal chemical vapor deposition (CVD) [and laser-assisted CVD]. In laser-assisted CVD, low-crystalline silicon (Si) was quickly deposited at the VACNT subsurfaces/surfaces followed by the formation of high-crystalline Si layers, thus resulting in noninfiltrated composite structures. Unlike laser-assisted CVD, thermal CVD activated the precursors inside and outside the VACNTs simultaneously, which realized uniform infiltrated VACNT/Si composite structures. The growth mechanisms for infiltrated and noninfiltrated VACNT/ceramic composites, which we attributed to the different temperature distributions and gas diffusion mechanism in VACNTs, were investigated. More importantly, the as-farbicated composite structures exhibited excellent multifunctional properties, such as excellent antioxidative ability (up to 1100 °C), high thermal stability (up to 1400 °C), good high velocity hot gas erosion resistance, and good electrical conductivity (∼8.95 Sm -1 at 823 K). The work presented here brings a simple, new approach to the fabrication of advanced composite structures for hot electrode applications.

  1. Flexible Black-Phosphorus Nanoflake/Carbon Nanotube Composite Paper for High-Performance All-Solid-State Supercapacitors.

    Science.gov (United States)

    Yang, Bingchao; Hao, Chunxue; Wen, Fusheng; Wang, Bochong; Mu, Congpu; Xiang, Jianyong; Li, Lei; Xu, Bo; Zhao, Zhisheng; Liu, Zhongyuan; Tian, Yongjun

    2017-12-27

    We proposed a simple route for fabrication of the flexible BP nanoflake/carbon nanotube (CNT) composite paper as flexible electrodes in all-solid-state supercapacitors. The highly conductive CNTs not only play a role as active materials but also increase conductivity of the hybrid electrode, enhance electrolyte shuttling and prevent the restacking between BP nanoflakes. The fabricated flexible all-solid-state supercapacitor (ASSP) device at the mass proportion of BP/CNTs 1:4 was found to deliver the highest volumetric capacitance of up to 41.1 F/cm 3 at 0.005 V/s, superior to the ASSP based on the bare graphene or BP. The BP/CNTs (1:4) device delivers a rapid charging/discharging up to 500 V/s, which exhibits the characteristic of a high power density of 821.62 W/cm 3 , while having outstanding mechanical flexibility and high cycling stability over 10 000 cycles (91.5% capacitance retained). Moreover the BP/CNTs (1:4) ASSP device still retains large volumetric capacitance (35.7 F/cm 3 at the scan rate of 0.005 V/s) even after 11 months. In addition, the ASSP of BP/CNTs (1:4) exhibits high energy density of 5.71 mWh/cm 3 and high power density of 821.62 W/cm 3 . As indicated in our work, the strategy of assembling stacked-layer composites films will open up novel possibility for realizing BP and CNTs in new-concept thin-film energy storage devices.

  2. Carbon nanotube network film directly grown on carbon cloth for high-performance solid-state flexible supercapacitors

    International Nuclear Information System (INIS)

    Zhou, Cheng; Liu, Jinping

    2014-01-01

    Carbon nanotubes (CNTs) have received increasing attention as electrode materials for high-performance supercapacitors. We herein present a straightforward method to synthesize CNT films directly on carbon cloths as electrodes for all-solid-state flexible supercapacitors (AFSCs). The as-made highly conductive electrodes possess a three-dimensional (3D) network architecture for fast ion diffusion and good flexibility, leading to an AFSC with a specific capacitance of 106.1 F g −1 , an areal capacitance of 38.75 mF cm −2 , an ultralong cycle life of 100 000 times (capacitance retention: 99%), a good rate capability (can scan at 1000 mV s −1 , at which the capacitance is still ∼37.8% of that at 5 mV s −1 ), a high energy density (2.4 μW h cm −2 ) and a high power density (19 mW cm −2 ). Moreover, our AFSC maintains excellent electrochemical attributes even with serious shape deformation (bending, folding, etc), high mechanical pressure (63 kPa) and a wide temperature window (up to 100 ° C). After charging for only 5 s, three such AFSC devices connected in series can efficiently power a red round LED for 60 s. Our work could pave the way for the design of practical AFSCs, which are expected to be used for various flexible portable/wearable electronic devices in the future. (paper)

  3. Functional materials based on carbon nanotubes: Carbon nanotube actuators and noncovalent carbon nanotube modification

    Science.gov (United States)

    Fifield, Leonard S.

    Carbon nanotubes have attractive inherent properties that encourage the development of new functional materials and devices based on them. The use of single wall carbon nanotubes as electromechanical actuators takes advantage of the high mechanical strength, surface area and electrical conductivity intrinsic to these molecules. The work presented here investigates the mechanisms that have been discovered for actuation of carbon nanotube paper: electrostatic, quantum chemical charge injection, pneumatic and viscoelastic. A home-built apparatus for the measurement of actuation strain is developed and utilized in the investigation. An optical fiber switch, the first demonstrated macro-scale device based on the actuation of carbon nanotubes, is described and its performance evaluated. Also presented here is a new general process designed to modify the surface of carbon nanotubes in a non-covalent, non-destructive way. This method can be used to impart new functionalities to carbon nanotube samples for a variety of applications including sensing, solar energy conversion and chemical separation. The process described involves the achievement of large degrees of graphitic surface coverage with polycyclic aromatic hydrocarbons through the use of supercritical fluids. These molecules are bifunctional agents that anchor a desired chemical group to the aromatic surface of the carbon nanotubes without adversely disrupting the conjugated backbone that gives rise the attractive electronic and physical properties of the nanotubes. Both the nanotube functionalization work and the actuator work presented here emphasize how an understanding and control of nanoscale structure and phenomena can be of vital importance in achieving desired performance for active materials. Opportunities for new devices with improved function over current state-of-the-art can be envisioned and anticipated based on this understanding and control.

  4. Gel spinning of PVA composite fibers with high content of multi-walled carbon nanotubes and graphene oxide hybrids

    International Nuclear Information System (INIS)

    Wei, Yizhe; Lai, Dengpan; Zou, Liming; Ling, Xinlong; Lu, Hongwei; Xu, Yongjing

    2015-01-01

    In this report, poly (vinyl alcohol) (PVA) composite fibers with high content of multi-walled carbon nanotubes and graphene oxide (MWCNTs-GO) hybrids were prepared by gel spinning, and were characterized by TGA, DSC, SEM, XL-2 yarn strength tester and electrical conductivity measurement. The total content of MWCNTs-GO hybrids in the PVA composite fibers, which is up to 25 wt%, was confirmed by TGA analysis. The DSC measurement shows that the melting and crystallization peaks decreased after the addition of nano-fillers. This is due to the reason that the motion of PVA chains is completely confined by strong hydrogen bonding interaction between PVA and nano-fillers. After the addtion of GO, the dispersibility of MWCNTs in composite fibers improved slightly. And the tensile strength and Young's modulus increased by 38% and 67%, respectively. This is caused by the increased hydrogen bonding interaction and synergistic effect through hybridization of MWCNTs and GO. More significantly, the electrical conductivity of PVA/MWCNTs/GO composite fibers enhanced by three orders of magnitude with the addition of GO. (paper)

  5. High methanol oxidation activity of electrocatalysts supported by directly grown nitrogen-containing carbon nanotubes on carbon cloth

    International Nuclear Information System (INIS)

    Wang, C.-H.; Shih, H.-C.; Tsai, Y.-T.; Du, H.-Y.; Chen, L.-C.; Chen, K.-H.

    2006-01-01

    The microstructure and electrochemical activity of the Pt-Ru supported by nitrogen-containing carbon nanotubes (CN x NTs) directly grown on the carbon cloth have been investigated. The CN x NTs directly grown on the carbon cloth (CN x NTs-carbon cloth composite electrode) were synthesized using microwave-plasma-enhanced chemical vapour deposition first and then use as the template to support the Pt-Ru nanoclusters subsequently sputtered on. The ferricyanide/ferrocyanide redox reaction in cyclic voltammetry (CV) measurements showed a faster electron transfer on the CN x NTs-carbon cloth composite electrode than the one with carbon cloth alone. Comparing their methanol oxidation abilities, it is found that the Pt-Ru nanoclusters supported by the CN x NTs-carbon cloth composite electrode have considerably higher electrocatalytic activity than the carbon cloth counterpart. This result suggests high performance of the CN x NTs-carbon cloth composite electrode, and demonstrates its suitability for direct methanol fuel cell applications

  6. Simple and cost-effective method of highly conductive and elastic carbon nanotube/polydimethylsiloxane composite for wearable electronics.

    Science.gov (United States)

    Kim, Jeong Hun; Hwang, Ji-Young; Hwang, Ha Ryeon; Kim, Han Seop; Lee, Joong Hoon; Seo, Jae-Won; Shin, Ueon Sang; Lee, Sang-Hoon

    2018-01-22

    The development of various flexible and stretchable materials has attracted interest for promising applications in biomedical engineering and electronics industries. This interest in wearable electronics, stretchable circuits, and flexible displays has created a demand for stable, easily manufactured, and cheap materials. However, the construction of flexible and elastic electronics, on which commercial electronic components can be mounted through simple and cost-effective processing, remains challenging. We have developed a nanocomposite of carbon nanotubes (CNTs) and polydimethylsiloxane (PDMS) elastomer. To achieve uniform distributions of CNTs within the polymer, an optimized dispersion process was developed using isopropyl alcohol (IPA) and methyl-terminated PDMS in combination with ultrasonication. After vaporizing the IPA, various shapes and sizes can be easily created with the nanocomposite, depending on the mold. The material provides high flexibility, elasticity, and electrical conductivity without requiring a sandwich structure. It is also biocompatible and mechanically stable, as demonstrated by cytotoxicity assays and cyclic strain tests (over 10,000 times). We demonstrate the potential for the healthcare field through strain sensor, flexible electric circuits, and biopotential measurements such as EEG, ECG, and EMG. This simple and cost-effective fabrication method for CNT/PDMS composites provides a promising process and material for various applications of wearable electronics.

  7. High methanol oxidation activity of electrocatalysts supported by directly grown nitrogen-containing carbon nanotubes on carbon cloth

    Energy Technology Data Exchange (ETDEWEB)

    Wang, C.-H. [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu, Taiwan (China); Shih, H.-C. [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu, Taiwan (China); Institue of Materials Science and Nano Technology, Chinese Culture University, Taipei, Taiwan (China); Tsai, Y.-T. [Institue of Materials Science and Nano Technology, Chinese Culture University, Taipei, Taiwan (China); Du, H.-Y. [Institue of Materials Science and Nano Technology, Chinese Culture University, Taipei, Taiwan (China); Chen, L.-C. [Center for Condensed Matter Sciences, National Taiwan University, Taipei, Taiwan (China); Chen, K.-H. [Center for Condensed Matter Sciences, National Taiwan University, Taipei, Taiwan (China) and Institue of Atomic and Molecular Science, Academia Sinica, Taipei, Taiwan (China)]. E-mail: chenkh@pub.iams.sinica.edu.tw

    2006-12-01

    The microstructure and electrochemical activity of the Pt-Ru supported by nitrogen-containing carbon nanotubes (CN {sub x} NTs) directly grown on the carbon cloth have been investigated. The CN {sub x} NTs directly grown on the carbon cloth (CN {sub x} NTs-carbon cloth composite electrode) were synthesized using microwave-plasma-enhanced chemical vapour deposition first and then use as the template to support the Pt-Ru nanoclusters subsequently sputtered on. The ferricyanide/ferrocyanide redox reaction in cyclic voltammetry (CV) measurements showed a faster electron transfer on the CN {sub x} NTs-carbon cloth composite electrode than the one with carbon cloth alone. Comparing their methanol oxidation abilities, it is found that the Pt-Ru nanoclusters supported by the CN {sub x} NTs-carbon cloth composite electrode have considerably higher electrocatalytic activity than the carbon cloth counterpart. This result suggests high performance of the CN {sub x} NTs-carbon cloth composite electrode, and demonstrates its suitability for direct methanol fuel cell applications.

  8. Highly Selective and Sensitive Detection of Acetylcholine Using Receptor-Modified Single-Walled Carbon Nanotube Sensors

    Science.gov (United States)

    Xu, Shihong; Kim, Byeongju; Song, Hyun Seok; Jin, Hye Jun; Park, Eun Jin; Lee, Sang Hun; Lee, Byung Yang; Park, Tai Hyun; Hong, Seunghun

    2015-03-01

    Acetylcholine (ACh) is a neurotransmitter in a human central nervous system and is related to various neural functions such as memory, learning and muscle contractions. Dysfunctional ACh regulations in a brain can induce several neuropsychiatric diseases such as Alzheimer's disease, Parkinson's disease and myasthenia gravis. In researching such diseases, it is important to measure the concentration of ACh in the extracellular fluid of the brain. Herein, we developed a highly sensitive and selective ACh sensor based on single-walled carbon nanotube-field effect transistors (swCNT-FETs). In our work, M1 mAChR protein, an ACh receptor, was expressed in E.coli and coated on swCNT-FETs with lipid membranes. Here, the binding of ACh onto the receptors could be detected by monitoring the change of electrical currents in the underlying swCNT-FETs, allowing the real-time detection of ACh at a 100 pM concentration. Furthermore, our sensor could selectively detect ACh from other neurotransmitters. This is the first report of the real-time sensing of ACh utilizing specific binding between the ACh and M1 mAChR, and it may lead to breakthroughs in various biomedical applications such as drug screening and disease diagnosis.

  9. Effect of cooling rate on the properties of high density polyethylene/multi-walled carbon nanotube composites

    Energy Technology Data Exchange (ETDEWEB)

    Xiang, Dong; Harkin-Jones, Eileen [School of Mechanical and Aerospace Engineering, Queen’s University Belfast, BT9 5AH (United Kingdom); Linton, David [School of Electronics, Electrical Engineering and Computer Science, Queen’s University Belfast, BT9 5AH (United Kingdom)

    2015-05-22

    High density polyethylene (HDPE)/multi-walled carbon nanotube (MWCNT) nanocomposites were prepared by melt mixing using twin-screw extrusion. The extruded pellets were compression moulded at 200°C for 5min followed by cooling at different cooling rates (20°C/min and 300°C/min respectively) to produce sheets for characterization. Scanning electron microscopy (SEM) shows that the MWCNTs are uniformly dispersed in the HDPE. At 4 wt% addition of MWCNTs composite modulus increased by over 110% compared with the unfilled HDPE (regardless of the cooling rate). The yield strength of both unfilled and filled HDPE decreased after rapid cooling by about 10% due to a lower crystallinity and imperfect crystallites. The electrical percolation threshold of composites, irrespective of the cooling rate, is between a MWCNT concentration of 1∼2 wt%. Interestingly, the electrical resistivity of the rapidly cooled composite with 2 wt% MWCNTs is lower than that of the slowly cooled composites with the same MWCNT loading. This may be due to the lower crystallinity and smaller crystallites facilitating the formation of conductive pathways. This result may have significant implications for both process control and the tailoring of electrical conductivity in the manufacture of conductive HDPE/MWCNT nanocomposites.

  10. Effect of cooling rate on the properties of high density polyethylene/multi-walled carbon nanotube composites

    International Nuclear Information System (INIS)

    Xiang, Dong; Harkin-Jones, Eileen; Linton, David

    2015-01-01

    High density polyethylene (HDPE)/multi-walled carbon nanotube (MWCNT) nanocomposites were prepared by melt mixing using twin-screw extrusion. The extruded pellets were compression moulded at 200°C for 5min followed by cooling at different cooling rates (20°C/min and 300°C/min respectively) to produce sheets for characterization. Scanning electron microscopy (SEM) shows that the MWCNTs are uniformly dispersed in the HDPE. At 4 wt% addition of MWCNTs composite modulus increased by over 110% compared with the unfilled HDPE (regardless of the cooling rate). The yield strength of both unfilled and filled HDPE decreased after rapid cooling by about 10% due to a lower crystallinity and imperfect crystallites. The electrical percolation threshold of composites, irrespective of the cooling rate, is between a MWCNT concentration of 1∼2 wt%. Interestingly, the electrical resistivity of the rapidly cooled composite with 2 wt% MWCNTs is lower than that of the slowly cooled composites with the same MWCNT loading. This may be due to the lower crystallinity and smaller crystallites facilitating the formation of conductive pathways. This result may have significant implications for both process control and the tailoring of electrical conductivity in the manufacture of conductive HDPE/MWCNT nanocomposites

  11. Current-Fluctuation Mechanism of Field Emitters Using Metallic Single-Walled Carbon Nanotubes with High Crystallinity

    Directory of Open Access Journals (Sweden)

    Norihiro Shimoi

    2017-12-01

    Full Text Available Field emitters can be used as a cathode electrode in a cathodoluminescence device, and single-walled carbon nanotubes (SWCNTs that are synthesized by arc discharge are expected to exhibit good field emission (FE properties. However, a cathodoluminescence device that uses field emitters radiates rays whose intensity considerably fluctuates at a low frequency, and the radiant fluctuation is caused by FE current fluctuation. To solve this problem, is very important to obtain a stable output for field emitters in a cathodoluminescence device. The authors consider that the electron-emission fluctuation is caused by Fowler–Nordheim electron tunneling and that the electrons in the Fowler–Nordheim regime pass through an inelastic potential barrier. We attempted to develop a theoretical model to analyze the power spectrum of the FE current fluctuation using metallic SWCNTs as field emitters, owing to their electrical conductivity by determining their FE properties. Field emitters that use metallic SWCNTs with high crystallinity were successfully developed to achieve a fluctuating FE current from field emitters at a low frequency by employing inelastic electron tunneling. This paper is the first report of the successful development of an inelastic-electron-tunneling model with a Wentzel–Kramers–Brillouin approximation for metallic SWCNTs based on the evaluation of FE properties.

  12. A highly sensitive hydrogen peroxide amperometric sensor based on MnO2-modified vertically aligned multiwalled carbon nanotubes.

    Science.gov (United States)

    Xu, Bin; Ye, Min-Ling; Yu, Yu-Xiang; Zhang, Wei-De

    2010-07-26

    In this report, a highly sensitive amperometric sensor based on MnO(2)-modified vertically aligned multiwalled carbon nanotubes (MnO(2)/VACNTs) for determination of hydrogen peroxide (H(2)O(2)) was fabricated by electrodeposition. The morphology of the nanocomposite was characterized by scanning electron microscopy, energy-dispersive X-ray spectrometer and X-ray diffraction. Cyclic voltammetry, chronoamperometry and electrochemical impedance spectroscopy were applied to investigate the electrochemical properties of the MnO(2)/VACNTs nanocomposite electrode. The mechanism for the electrochemical reaction of H(2)O(2) at the MnO(2)/VACNTs nanocomposite electrode was also discussed. In borate buffer (pH 7.8, 0.20 M), the MnO(2)/VACNTs nanocomposite electrode exhibits a linear dependence (R=0.998) on the concentration of H(2)O(2) from 1.2 x 10(-6)M to 1.8 x 10(-3)M, a high sensitivity of 1.08 x 10(6) microA M(-1) cm(-2) and a detection limit of 8.0 x 10(-7) M (signal/noise=3). Meanwhile, the MnO(2)/VACNTs nanocomposite electrode is also highly resistant towards typical inorganic salts and some biomolecules such as acetic acid, citric acid, uric acid and D-(+)-glucose, etc. In addition, the sensor based on the MnO(2)/VACNTs nanocomposite electrode was applied for the determination of trace of H(2)O(2) in milk with high accuracy, demonstrating its potential for practical application. Copyright 2010 Elsevier B.V. All rights reserved.

  13. Electrochemical biosensing based on polypyrrole/titania nanotube hybrid

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Yibing, E-mail: ybxie@seu.edu.cn; Zhao, Ye

    2013-12-01

    The glucose oxidase (GOD) modified polypyrrole/titania nanotube enzyme electrode is fabricated for electrochemical biosensing application. The titania nanotube array is grown directly on a titanium substrate through an anodic oxidation process. A thin film of polypyrrole is coated onto titania nanotube array to form polypyrrole/titania nanotube hybrid through a normal pulse voltammetry process. GOD-polypyrrole/titania nanotube enzyme electrode is prepared by the covalent immobilization of GOD onto polypyrrole/titania nanotube hybrid via the cross-linker of glutaraldehyde. The morphology and microstructure of nanotube electrodes are characterized by field emission scanning electron microscopy and Fourier transform infrared analysis. The biosensing properties of this nanotube enzyme electrode have been investigated by means of cyclic voltammetry and chronoamperometry. The hydrophilic polypyrrole/titania nanotube hybrid provides highly accessible nanochannels for GOD encapsulation, presenting good enzymatic affinity. As-formed GOD-polypyrrole/titania nanotube enzyme electrode well conducts bioelectrocatalytic oxidation of glucose, exhibiting a good biosensing performance with a high sensitivity, low detection limit and wide linear detection range. - Graphical abstract: The schematic diagram presents the fabrication of glucose oxidase modified polypyrrole/titania (GOD-PPy/TiO{sub 2}) nanotube enzyme electrode for biosensing application. - Highlights: • Hydrophilic polypyrrole/titania nanotube hybrid is well used as biosensing substrate. • Polypyrrole promotes GOD immobilization on titania nanotubes via glutaraldehyde. • GOD-polypyrrole/titania enzyme electrode shows good bioelectrocatalytic reactivity.

  14. Electrochemical biosensing based on polypyrrole/titania nanotube hybrid

    International Nuclear Information System (INIS)

    Xie, Yibing; Zhao, Ye

    2013-01-01

    The glucose oxidase (GOD) modified polypyrrole/titania nanotube enzyme electrode is fabricated for electrochemical biosensing application. The titania nanotube array is grown directly on a titanium substrate through an anodic oxidation process. A thin film of polypyrrole is coated onto titania nanotube array to form polypyrrole/titania nanotube hybrid through a normal pulse voltammetry process. GOD-polypyrrole/titania nanotube enzyme electrode is prepared by the covalent immobilization of GOD onto polypyrrole/titania nanotube hybrid via the cross-linker of glutaraldehyde. The morphology and microstructure of nanotube electrodes are characterized by field emission scanning electron microscopy and Fourier transform infrared analysis. The biosensing properties of this nanotube enzyme electrode have been investigated by means of cyclic voltammetry and chronoamperometry. The hydrophilic polypyrrole/titania nanotube hybrid provides highly accessible nanochannels for GOD encapsulation, presenting good enzymatic affinity. As-formed GOD-polypyrrole/titania nanotube enzyme electrode well conducts bioelectrocatalytic oxidation of glucose, exhibiting a good biosensing performance with a high sensitivity, low detection limit and wide linear detection range. - Graphical abstract: The schematic diagram presents the fabrication of glucose oxidase modified polypyrrole/titania (GOD-PPy/TiO 2 ) nanotube enzyme electrode for biosensing application. - Highlights: • Hydrophilic polypyrrole/titania nanotube hybrid is well used as biosensing substrate. • Polypyrrole promotes GOD immobilization on titania nanotubes via glutaraldehyde. • GOD-polypyrrole/titania enzyme electrode shows good bioelectrocatalytic reactivity

  15. High-performance Li-ion Sn anodes with enhanced electrochemical properties using highly conductive TiN nanotubes array as a 3D multifunctional support

    Science.gov (United States)

    Pu, Jun; Du, Hongxiu; Wang, Jian; Wu, Wenlu; Shen, Zihan; Liu, Jinyun; Zhang, Huigang

    2017-08-01

    High capacity electrodes are demanded to increase the energy and power density of lithium ion batteries. However, the cycling and rate properties are severely affected by the large volume changes caused by the lithium insertion and extraction. Structured electrodes with mechanically stable scaffolds are widely developed to mitigate the adverse effects of volume changes. Tin, as a promising anode material, receives great attentions because of its high theoretic capacity. There is a critical value of tin particle size above which tin anodes readily crack, leading to low cyclability. The electrode design using mechanical scaffolds must retain tin particles below the critical size and concurrently enable high volumetric capacity. It is a challenge to guarantee the critical size for high cyclability and space utilization for high volumetric capacity. This study provides a highly conductive TiN nanotubes array with submicron diameters, which enable thin tin coating without sacrificing the volumetric capacity. Such a structured electrode delivers a capacity of 795 mAh gSn-1 (Sn basis) and 1812 mAh cmel-3 (electrode basis). The long-term cycling shows only 0.04% capacity decay per cycle.

  16. Synthesis of highly aligned carbon nanotubes by one-step liquid-phase process: Effects of carbon sources on morphology of carbon nanotubes

    Science.gov (United States)

    Yamagiwa, Kiyofumi; Kuwano, Jun

    2017-06-01

    This paper describes a unique and innovative synthesis technique for carbon nanotubes (CNTs) by a one-step liquid-phase process under ambient pressure. Vertically aligned multi-walled CNT arrays with a maximum height of 100 µm are prepared on stainless steel substrates, which are submerged and electrically heated in straight-chain primary alcohols with n C = 1-4 (n C: number of C atoms in the molecule) containing an appropriate amount of cobalt-based organometallic complex as a catalyst precursor. Structural isomers of butanol were also used for the synthesis to examine the effects of structural factors on the morphology of the deposited products. Notably, 2-methyl-2-propanol, which is a tertiary alcohol, produced only a small amount of low-crystallinity carbonaceous deposits, whereas vertically aligned CNTs were grown from the other isomers of butanol. These results suggest that the presence or absence of β-hydrogen in the molecular structure is a key factor for understanding the dissociation behavior of the carbon source molecules on the catalyst.

  17. High resolution stationary digital breast tomosynthesis using distributed carbon nanotube x-ray source array.

    Science.gov (United States)

    Qian, Xin; Tucker, Andrew; Gidcumb, Emily; Shan, Jing; Yang, Guang; Calderon-Colon, Xiomara; Sultana, Shabana; Lu, Jianping; Zhou, Otto; Spronk, Derrek; Sprenger, Frank; Zhang, Yiheng; Kennedy, Don; Farbizio, Tom; Jing, Zhenxue

    2012-04-01

    The purpose of this study is to investigate the feasibility of increasing the system spatial resolution and scanning speed of Hologic Selenia Dimensions digital breast tomosynthesis (DBT) scanner by replacing the rotating mammography x-ray tube with a specially designed carbon nanotube (CNT) x-ray source array, which generates all the projection images needed for tomosynthesis reconstruction by electronically activating individual x-ray sources without any mechanical motion. The stationary digital breast tomosynthesis (s-DBT) design aims to (i) increase the system spatial resolution by eliminating image blurring due to x-ray tube motion and (ii) reduce the scanning time. Low spatial resolution and long scanning time are the two main technical limitations of current DBT technology. A CNT x-ray source array was designed and evaluated against a set of targeted system performance parameters. Simulations were performed to determine the maximum anode heat load at the desired focal spot size and to design the electron focusing optics. Field emission current from CNT cathode was measured for an extended period of time to determine the stable life time of CNT cathode for an expected clinical operation scenario. The source array was manufactured, tested, and integrated with a Selenia scanner. An electronic control unit was developed to interface the source array with the detection system and to scan and regulate x-ray beams. The performance of the s-DBT system was evaluated using physical phantoms. The spatially distributed CNT x-ray source array comprised 31 individually addressable x-ray sources covering a 30 angular span with 1 pitch and an isotropic focal spot size of 0.6 mm at full width at half-maximum. Stable operation at 28 kV(peak) anode voltage and 38 mA tube current was demonstrated with extended lifetime and good source-to-source consistency. For the standard imaging protocol of 15 views over 14, 100 mAs dose, and 2 × 2 detector binning, the projection

  18. Quantum conductance of carbon nanotube peapods

    International Nuclear Information System (INIS)

    Yoon, Young-Gui; Mazzoni, Mario S.C.; Louie, Steven G.

    2003-01-01

    We present a first-principles study of the quantum conductance of hybrid nanotube systems consisting of single-walled carbon nanotubes (SWCNTs) encapsulating either an isolated single C60 molecule or a chain of C60 molecules (nanotube peapods). The calculations show a rather weak bonding interaction between the fullerenes and the SWCNTs. The conductance of a (10,10) SWCNT with a single C60 molecule is virtually unaffected at the Fermi level, but exhibits quantized resonant reductions at the molecular levels. The nanotube peapod arrangement gives rise to high density of states for the fullerene highest occupied molecular orbital and lowest unoccupied molecular orbital bands

  19. Sustainable design of high-performance microsized microbial fuel cell with carbon nanotube anode and air cathode

    KAUST Repository

    Mink, Justine E.

    2013-08-27

    Microbial fuel cells (MFCs) are a promising alternative energy source that both generates electricity and cleans water. Fueled by liquid wastes such as wastewater or industrial wastes, the microbial fuel cell converts waste into energy. Microsized MFCs are essentially miniature energy harvesters that can be used to power on-chip electronics, lab-on-a-chip devices, and/or sensors. As MFCs are a relatively new technology, microsized MFCs are also an important rapid testing platform for the comparison and introduction of new conditions or materials into macroscale MFCs, especially nanoscale materials that have high potential for enhanced power production. Here we report a 75 μL microsized MFC on silicon using CMOS-compatible processes and employ a novel nanomaterial with exceptional electrochemical properties, multiwalled carbon nanotubes (MWCNTs), as the on-chip anode. We used this device to compare the usage of the more commonly used but highly expensive anode material gold, as well as a more inexpensive substitute, nickel. This is the first anode material study done using the most sustainably designed microsized MFC to date, which utilizes ambient oxygen as the electron acceptor with an air cathode instead of the chemical ferricyanide and without a membrane. Ferricyanide is unsustainable, as the chemical must be continuously refilled, while using oxygen, naturally found in air, makes the device mobile and is a key step in commercializing this for portable technology such as lab-on-a-chip for point-of-care diagnostics. At 880 mA/m2 and 19 mW/m2 the MWCNT anode outperformed the others in both current and power densities with between 6 and 20 times better performance. All devices were run for over 15 days, indicating a stable and high-endurance energy harvester already capable of producing enough power for ultra-low-power electronics and able to consistently power them over time. © 2013 American Chemical Society.

  20. Facile synthesis of high quality multi-walled carbon nanotubes on novel 3D KIT-6: application in high performance dye-sensitized solar cells

    Science.gov (United States)

    Balamurugan, Jayaraman; Pandurangan, Arumugam; Kim, Nam Hoon; Lee, Joong Hee

    2014-12-01

    A novel hard templating strategy for the synthesis of high quality multi-walled carbon nanotubes (MWCNTs) with a uniform diameter was developed. MWCNTs were successfully synthesized through chemical vapour deposition (CVD) using acetylene by employing 3D bicontinuous mesoporous silica (KIT-6) as a hard template and used as the counter electrode in dye-sensitized solar cells (DSSCs). Here, we report that Ni-Cr-KIT-6 and Co-Cr-KIT-6 systems are the most suitable catalysts for the growth of MWCNTs. Raman spectroscopy and TEM analysis revealed that the synthesized MWCNTs were of high quality and well graphitized. Impressively, DSSCs with a MWCNT counter electrode demonstrated high power conversion efficiencies (PCEs) of up to 10.53%, which was significantly higher than that of 9.87% obtained for a DSSC with a conventional Pt counter electrode. Moreover, MWCNTs had a charge transfer resistance (Rct) of only 0.74 Ω cm2 towards the I3-/I- electrolyte commonly applied in DSSCs, which is several orders of magnitude lower than that of a typical Pt electrode (2.78 Ω cm2). These results indicate that the synthesized MWCNT counter electrodes are versatile candidates that can increase the power conversion efficiency (PCE) of DSSCs.A novel hard templating strategy for the synthesis of high quality multi-walled carbon nanotubes (MWCNTs) with a uniform diameter was developed. MWCNTs were successfully synthesized through chemical vapour deposition (CVD) using acetylene by employing 3D bicontinuous mesoporous silica (KIT-6) as a hard template and used as the counter electrode in dye-sensitized solar cells (DSSCs). Here, we report that Ni-Cr-KIT-6 and Co-Cr-KIT-6 systems are the most suitable catalysts for the growth of MWCNTs. Raman spectroscopy and TEM analysis revealed that the synthesized MWCNTs were of high quality and well graphitized. Impressively, DSSCs with a MWCNT counter electrode demonstrated high power conversion efficiencies (PCEs) of up to 10.53%, which was

  1. Thermal performance analysis of a flat heat pipe working with carbon nanotube-water nanofluid for cooling of a high heat flux heater

    Science.gov (United States)

    Arya, A.; Sarafraz, M. M.; Shahmiri, S.; Madani, S. A. H.; Nikkhah, V.; Nakhjavani, S. M.

    2018-04-01

    Experimental investigation on the thermal performance of a flat heat pipe working with carbon nanotube nanofluid is conducted. It is used for cooling a heater working at high heat flux conditions up to 190 kW/m2. The heat pipe is fabricated from aluminium and is equipped with rectangular fin for efficient cooling of condenser section. Inside the heat pipe, a screen mesh was inserted as a wick structure to facilitate the capillary action of working fluid. Influence of different operating parameters such as heat flux, mass concentration of carbon nanotubes and filling ratio of working fluid on thermal performance of heat pipe and its thermal resistance are investigated. Results showed that with an increase in heat flux, the heat transfer coefficient in evaporator section of the heat pipe increases. For filling ratio, however, there is an optimum value, which was 0.8 for the test heat pipe. In addition, CNT/water enhanced the heat transfer coefficient up to 40% over the deionized water. Carbon nanotubes intensified the thermal performance of wick structure by creating a fouling layer on screen mesh structure, which changes the contact angle of liquid with the surface, intensifying the capillary forces.

  2. A novel extraction technique based on carbon nanotubes reinforced hollow fiber solid/liquid microextraction for the measurement of piroxicam and diclofenac combined with high performance liquid chromatography.

    Science.gov (United States)

    Song, Xin-Yue; Shi, Yan-Ping; Chen, Juan

    2012-10-15

    A novel design of carbon nanotubes reinforced hollow fiber solid/liquid phase microextraction (CNTs-HF-SLPME) was developed to determine piroxicam and diclofenac in different real water samples. Functionalized multi-walled carbon nanotubes (MWCNTs) were held in the pores of hollow fiber with sol-gel technology. The pores and lumen of carbon nanotubes reinforced hollow fiber were subsequently filled with a μL volume of organic solvent (1-octanol), and then the whole assembly was used for the extraction of the target analytes in direct immersion sampling mode. The target analytes were extracted from the sample by two extractants, one of which is organic solvent placed inside the pores and lumen of hollow fiber and the other one is CNTs held in the pores of hollow fiber. After extraction, the analytes were desorbed in acetonitrile and analyzed using high performance liquid chromatography. This novel extraction mode showed more excellent extraction performance in comparison with conventional hollow fiber liquid microextraction (without adding CNTs) and carbon nanotubes reinforced hollow fiber solid microextraction (CNTs held in the pores of hollow fiber, but no organic solvents placed inside the lumen of hollow fiber) under the respective optimum conditions. This method provided 47- and 184-fold enrichment factors for piroxicam and diclofenac, respectively, good inter-fiber repeatability and batch-to-batch reproducibility. Linearity was observed in the range of 20-960 μg L(-1) for piroxicam, and 10-2560 μg L(-1) for diclofenac, with correlation coefficients of 0.9985 and 0.9989, respectively. The limits of detection were 4.58 μg L(-1) for piroxicam and 0.40 μg L(-1) for diclofenac. Copyright © 2012 Elsevier B.V. All rights reserved.

  3. Layer-by-layer assembled polyaniline nanofiber/multiwall carbon nanotube thin film electrodes for high-power and high-energy storage applications.

    Science.gov (United States)

    Hyder, Md Nasim; Lee, Seung Woo; Cebeci, Fevzi Ç; Schmidt, Daniel J; Shao-Horn, Yang; Hammond, Paula T

    2011-11-22

    Thin film electrodes of polyaniline (PANi) nanofibers and functionalized multiwall carbon nanotubes (MWNTs) are created by layer-by-layer (LbL) assembly for microbatteries or -electrochemical capacitors. Highly stable cationic PANi nanofibers, synthesized from the rapid aqueous phase polymerization of aniline, are assembled with carboxylic acid functionalized MWNT into LbL films. The pH-dependent surface charge of PANi nanofibers and MWNTs allows the system to behave like weak polyelectrolytes with controllable LbL film thickness and morphology by varying the number of bilayers. The LbL-PANi/MWNT films consist of a nanoscale interpenetrating network structure with well developed nanopores that yield excellent electrochemical performance for energy storage applications. These LbL-PANi/MWNT films in lithium cell can store high volumetric capacitance (~238 ± 32 F/cm(3)) and high volumetric capacity (~210 mAh/cm(3)). In addition, rate-dependent galvanostatic tests show LbL-PANi/MWNT films can deliver both high power and high energy density (~220 Wh/L(electrode) at ~100 kW/L(electrode)) and could be promising positive electrode materials for thin film microbatteries or electrochemical capacitors. © 2011 American Chemical Society

  4. Hierarchically structured Ni(3)S(2)/carbon nanotube composites as high performance cathode materials for asymmetric supercapacitors.

    Science.gov (United States)

    Dai, Chao-Shuan; Chien, Pei-Yi; Lin, Jeng-Yu; Chou, Shu-Wei; Wu, Wen-Kai; Li, Ping-Hsuan; Wu, Kuan-Yi; Lin, Tsung-Wu

    2013-11-27

    The Ni3S2 nanoparticles with the diameters ranging from 10 to 80 nm are grown on the backbone of conductive multiwalled carbon nanotubes (MWCNTs) using a glucose-assisted hydrothermal method. It is found that the Ni3S2 nanoparticles deposited on MWCNTs disassemble into smaller components after the composite electrode is activated by the consecutive cyclic voltammetry scan in a 2 M KOH solution. Therefore, the active surface area of the Ni3S2 nanoparticles is increased, which further enhances the capacitive performance of the composite electrode. Because the synergistic effect of the Ni3S2 nanoparticles and MWCNTs on the capacitive performance of the composite electrode is pronounced, the composite electrode shows a high specific capacitance of 800 F/g and great cycling stability at a current density of 3.2 A/g. To examine the capacitive performance of the composite electrode in a full-cell configuration, an asymmetric supercapacitor device was fabricated by using the composite of Ni3S2 and MWCNTs as the cathode and activated carbon as the anode. The fabricated device can be operated reversibly between 0 and 1.6 V, and obtain a high specific capacitance of 55.8 F/g at 1 A/g, which delivers a maximum energy density of 19.8 Wh/kg at a power density of 798 W/kg. Furthermore, the asymmetric supercapacitor shows great stability based on the fact that the device retains 90% of its initial capacitance after a consecutive 5000 cycles of galvanostatic charge-discharge performed at a current density of 4 A/g.

  5. Transition metal doped poly(aniline-co-pyrrole)/multi-walled carbon nanotubes nanocomposite for high performance supercapacitor electrode materials

    International Nuclear Information System (INIS)

    Dhibar, Saptarshi; Bhattacharya, Pallab; Hatui, Goutam; Das, C.K.

    2015-01-01

    Highlights: • The CuCl 2 doped copolymer (PANI and PPy)/MWCNTs nanocomposite was prepared. • The nanocomposite achieved highest specific capacitance of 383 F/g at a 0.5 A/g. • Nanocomposite exhibits better energy density as well as power density. • The nanocomposite also showed better electrical conductivity at room temperature. • The nanocomposite can be used as promising electrode materials for supercapacitor. - Abstract: In this present communication, copolymer of polyaniline (PANI) and polypyrrole (PPy) that is poly(aniline-co-pyrrole) [poly(An-co-Py)], copper chloride (CuCl 2 ) doped poly(aniline-co-pyrrole) [poly(An-co-Py) Cu], and CuCl 2 doped poly(aniline-co-pyrrole)/multi walled carbon nanotubes (MWCNTs) [poly(An-co-Py) Cu CNT] nanocomposite have been prepared by a simple and inexpensive in-situ chemical oxidative polymerization method, using ammonium persulfate (APS) as oxidant and hydrochloric acid (HCl) as dopant and investigated as high performance supercapacitor electrode materials. The possible interaction between CuCl 2 with copolymers and MWCNTs was investigated by Fourier transform infrared spectroscopy (FTIR) and UV–visible spectroscopy analysis. The morphological characteristic of all the electrode materials were analyzed by Field emission scanning electron microscopy (FESEM) and Transmission electron microscopy (TEM) study. The electrochemical characterizations of all the electrode materials were carried out by three electrode probe method where, standard calomel electrode and platinum were used as reference and counter electrodes, respectively. Among all the electrode materials, poly(An-co-Py) Cu CNT nanocomposite achieved highest specific capacitance value of 383 F/g at 0.5 A/g scan rate. The nanocomposite showed better electrical conductivity at room temperature and also attained nonlinear current–voltage characteristic. Based on the superior electrochemical as well as other properties the as prepared nanocomposite can be used

  6. Transition metal doped poly(aniline-co-pyrrole)/multi-walled carbon nanotubes nanocomposite for high performance supercapacitor electrode materials

    Energy Technology Data Exchange (ETDEWEB)

    Dhibar, Saptarshi; Bhattacharya, Pallab; Hatui, Goutam; Das, C.K., E-mail: chapal12@yahoo.co.in

    2015-03-15

    Highlights: • The CuCl{sub 2} doped copolymer (PANI and PPy)/MWCNTs nanocomposite was prepared. • The nanocomposite achieved highest specific capacitance of 383 F/g at a 0.5 A/g. • Nanocomposite exhibits better energy density as well as power density. • The nanocomposite also showed better electrical conductivity at room temperature. • The nanocomposite can be used as promising electrode materials for supercapacitor. - Abstract: In this present communication, copolymer of polyaniline (PANI) and polypyrrole (PPy) that is poly(aniline-co-pyrrole) [poly(An-co-Py)], copper chloride (CuCl{sub 2}) doped poly(aniline-co-pyrrole) [poly(An-co-Py) Cu], and CuCl{sub 2} doped poly(aniline-co-pyrrole)/multi walled carbon nanotubes (MWCNTs) [poly(An-co-Py) Cu CNT] nanocomposite have been prepared by a simple and inexpensive in-situ chemical oxidative polymerization method, using ammonium persulfate (APS) as oxidant and hydrochloric acid (HCl) as dopant and investigated as high performance supercapacitor electrode materials. The possible interaction between CuCl{sub 2} with copolymers and MWCNTs was investigated by Fourier transform infrared spectroscopy (FTIR) and UV–visible spectroscopy analysis. The morphological characteristic of all the electrode materials were analyzed by Field emission scanning electron microscopy (FESEM) and Transmission electron microscopy (TEM) study. The electrochemical characterizations of all the electrode materials were carried out by three electrode probe method where, standard calomel electrode and platinum were used as reference and counter electrodes, respectively. Among all the electrode materials, poly(An-co-Py) Cu CNT nanocomposite achieved highest specific capacitance value of 383 F/g at 0.5 A/g scan rate. The nanocomposite showed better electrical conductivity at room temperature and also attained nonlinear current–voltage characteristic. Based on the superior electrochemical as well as other properties the as prepared

  7. Charge stabilization by reaction center protein immobilized to carbon nanotubes functionalized by amine groups and poly(3-thiophene acetic acid) conducting polymer

    Energy Technology Data Exchange (ETDEWEB)

    Szabo, T.; Magyar, M.; Nagy, L. [Department of Medical Physics and Informatics, University of Szeged, H-6720 Szeged (Hungary); Nemeth, Z.; Hernadi, K. [Department of Applied and Environmental Chemistry, University of Szeged, H-6720 Szeged (Hungary); Endrodi, B.; Bencsik, G.; Visy, Cs. [Department of Physical Chemistry and Materials Science, University of Szeged, H-6720 Szeged (Hungary); Horvath, E.; Magrez, A.; Forro, L. [Institute of Physics of Complex Matter, Ecole Polytechnique Federale de Lausanne, CH-1015 Lausanne (Switzerland)

    2012-12-15

    A large number of studies have indicated recently that photosynthetic reaction center proteins (RC) bind successfully to nanostructures and their functional activity is largely retained. The major goal of current research is to find the most efficient systems and conditions for the photoelectric energy conversion and for the stability of this bio-nanocomposite. In our studies, we immobilized the RC protein on multiwalled carbon nanotubes (MWNT) through specific chemical binding to amine functional groups and through conducting polymer (poly(3-thiophene acetic acid), PTAA). Both structural (TEM, AFM) and functional (absorption change and conductivity) measurements has shown that RCs could be bound effectively to functionalized CNTs. The kinetics of the light induced absorption change indicated that RCs were still active in the composite and there was an interaction between the protein cofactors and the CNTs. The light generated photocurrent was measured in an electrochemical cell with transparent CNT electrode designed specially for this experiment. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  8. Large-scale synthesis of high-purity well-aligned carbon nanotubes using pyrolysis of iron(II) phthalocyanine and acetylene

    Science.gov (United States)

    Liu, B. C.; Lee, T. J.; Lee, S. H.; Park, C. Y.; Lee, C. J.

    2003-08-01

    Well-aligned carbon nanotubes (CNTs) with high purity have been produced by pyrolysis of iron(II) phthalocyanine and acetylene at 800 °C. The synthesized CNTs have a length of 75 μm and diameters ranging from 20 to 60 nm. The CNTs have a bamboo-like structure and exhibit good crystallinity of graphite sheets. The growth rate of the CNTs was rapidly increased with adding C 2H 2. Our results demonstrate that the proposed growth method is suitable to large-scale synthesis of high-purity well-aligned CNTs on various substrates.

  9. Co(OH)2/RGO/NiO sandwich-structured nanotube arrays with special surface and synergistic effects as high-performance positive electrodes for asymmetric supercapacitors.

    Science.gov (United States)

    Xu, Han; Zhang, Chi; Zhou, Wen; Li, Gao-Ren

    2015-10-28

    High power density, high energy density and excellent cycling stability are the main requirements for high-performance supercapacitors (SCs) that will be widely used for portable consumer electronics and hybrid electric vehicles. Here we investigate novel types of hybrid Co(OH)2/reduced graphene oxide (RGO)/NiO sandwich-structured nanotube arrays (SNTAs) as positive electrodes for asymmetric supercapacitors (ASCs). The synthesized Co(OH)2/RGO/NiO SNTAs exhibit a significantly improved specific capacity (∼1470 F g(-1) at 5 mV s(-1)) and excellent cycling stability with ∼98% Csp retention after 10 000 cycles because of the fast transport and short diffusion paths for electroactive species, the high utilization rate of electrode materials, and special synergistic effects among Co(OH)2, RGO, and NiO. The high-performance ASCs are assembled using Co(OH)2/RGO/NiO SNTAs as positive electrodes and active carbon (AC) as negative electrodes, and they exhibit a high energy density (115 Wh kg(-1)), a high power density (27.5 kW kg(-1)) and an excellent cycling stability (less 5% Csp loss after 10 000 cycles). This study shows an important breakthrough in the design and fabrication of multi-walled hybrid nanotube arrays as positive electrodes for ASCs.

  10. Flexible graphene/carbon nanotube hybrid papers chemical-reduction-tailored by gallic acid for high-performance electrochemical capacitive energy storages

    Science.gov (United States)

    Yao, Lu; Zhou, Chao; Hu, Nantao; Hu, Jing; Hong, Min; Zhang, Liying; Zhang, Yafei

    2018-03-01

    Mechanically robust graphene papers with both high gravimetric and volumetric capacitances are desired for high-performance energy storages. However, it's still a challenge to tailor the structure of graphene papers in order to meet this requirement. In this work, a kind of chemical-reduction-tailored mechanically-robust reduced graphene oxide/carbon nanotube hybrid paper has been reported for high-performance electrochemical capacitive energy storages. Gallic acid (GA), as an excellent reducing agent, was used to reduce graphene oxide. Through vacuum filtration of gallic acid reduced graphene oxide (GA-rGO) and carboxylic multiwalled carbon nanotubes (MWCNTs) aqueous suspensions, mechanically robust GA-rGO/MWCNTs hybrid papers were obtained. The resultant hybrid papers showed high gravimetric capacitance of 337.6 F g-1 (0.5 A g-1) and volumetric capacitance of 151.2 F cm-3 (0.25 A cm-3). In addition, the assembled symmetric device based on the hybrid papers exhibited high gravimetric capacitance of 291.6 F g-1 (0.5 A g-1) and volumetric capacitance of 136.6 F cm-3 (0.25 A cm-3). Meanwhile, it exhibited excellent rate capability and cycling stability. Above all, this chemical reduction tailoring technique and the resultant high-performance GA-rGO/MWCNTs hybrid papers give an insight for designing high-performance electrodes and hold a great potential in the field of energy storages.

  11. Carbon nanotube network varactor

    International Nuclear Information System (INIS)

    Generalov, A A; Anoshkin, I V; Lioubtchenko, D V; Räisänen, A V; Erdmanis, M; Ovchinnikov, V; Nasibulin, A G

    2015-01-01

    Microelectromechanical system (MEMS) varactors based on a freestanding layer of single-walled carbon nanotube (SWCNT) films were designed, fabricated and tested. The freestanding SWCNT film was employed as a movable upper patch in the parallel plate capacitor of the MEMS. The measurements of the SWCNT varactors show very high tunability, nearly 100%, of the capacitance with a low actuation voltage of 10 V. The functionality of the varactor is improved by implementing a flexible nanocellulose aerogel filling. (paper)

  12. Carbon nanotube composite materials

    Science.gov (United States)

    O'Bryan, Gregory; Skinner, Jack L; Vance, Andrew; Yang, Elaine Lai; Zifer, Thomas

    2015-03-24

    A material consisting essentially of a vinyl thermoplastic polymer, un-functionalized carbon nanotubes and hydroxylated carbon nanotubes dissolved in a solvent. Un-functionalized carbon nanotube concentrations up to 30 wt % and hydroxylated carbon nanotube concentrations up to 40 wt % can be used with even small concentrations of each (less than 2 wt %) useful in producing enhanced conductivity properties of formed thin films.

  13. The influence of surface roughness and high pressure torsion on the growth of anodic titania nanotubes on pure titanium

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Nan; Gao, Nong, E-mail: N.Gao@soton.ac.uk; Starink, Marco J.

    2016-11-30

    Highlights: • HPT has substantially improved the UTS and Hv of pure Ti. • TNT layers was fabricated on UFG Ti made by HPT. • Influence of sample preparation on TNT layers was systematically studied. • Oxide dissolution was accelerated when TNTs formed on the HPT sample. - Abstract: Anodic titanium dioxide nanotube (TNT) arrays have wide applications in photocatalytic, catalysis, electronics, solar cells and biomedical implants. When TNT coatings are combined with severe plastic deformation (SPD), metal processing techniques which efficiently improve the strength of metals, a new generation of biomedical implant is made possible with both improved bulk and surface properties. This work investigated the effect of processing by high pressure torsion (HPT) and different mechanical preparations on the substrate and subsequently on the morphology of TNT layers. HPT processing was applied to refine the grain size of commercially pure titanium samples and substantially improved their strength and hardness. Subsequent anodization at 30 V in 0.25 wt.% NH{sub 4}F for 2 h to form TNT layers on sample surfaces prepared with different mechanical preparation methods was carried out. It appeared that the local roughness of the titanium surface on a microscopic level affected the TNT morphology more than the macroscopic surface roughness. For HPT-processed sample, the substrate has to be pre-treated by a mechanical preparation finer than 4000 grit for HPT to have a significant influence on TNTs. During the formation of TNT layers the oxide dissolution rate was increased for the ultrafine-grained microstructure formed due to HPT processing.

  14. Atomic layer deposition for coating of high aspect ratio TiO.sub.2./sub. nanotube layers

    Czech Academy of Sciences Publication Activity Database

    Zazpe, R.; Knaut, M.; Sopha, H.; Hromádko, L.; Albert, M.; Přikryl, J.; Gärtnerová, Viera; Bartha, J.W.; Macák, J. M.

    2016-01-01

    Roč. 32, č. 41 (2016), s. 10551-10558 ISSN 0743-7463 Institutional support: RVO:68378271 Keywords : aluminum * aluminum coatings * aspect ratio * coatings * nanotubes Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.833, year: 2016

  15. Energy dissipation and high-strain rate dynamic response of E-glass fiber composites with anchored carbon nanotubes

    Science.gov (United States)

    This study explores the mechanical properties of an E-glass fabric composite reinforced with anchored multi-walled carbon nanotubes (CNTs). The CNTs were grown on the E-glass fabric using a floating catalyst chemical vapor deposition procedure. The E-glass fabric with attached CNTs was then incorpor...

  16. A vertically aligned carbon nanotube-based impedance sensing biosensor for rapid and high sensitive detection of cancer cells.

    Science.gov (United States)

    Abdolahad, Mohammad; Taghinejad, Mohammad; Taghinejad, Hossein; Janmaleki, Mohsen; Mohajerzadeh, Shams

    2012-03-21

    A novel vertically aligned carbon nanotube based electrical cell impedance sensing biosensor (CNT-ECIS) was demonstrated for the first time as a more rapid, sensitive and specific device for the detection of cancer cells. This biosensor is based on the fast entrapment of cancer cells on vertically aligned carbon nanotube arrays and leads to mechanical and electrical interactions between CNT tips and entrapped cell membranes, changing the impedance of the biosensor. CNT-ECIS was fabricated through a photolithography process on Ni/SiO(2)/Si layers. Carbon nanotube arrays have been grown on 9 nm thick patterned Ni microelectrodes by DC-PECVD. SW48 colon cancer cells were passed over the surface of CNT covered electrodes to be specifically entrapped on elastic nanotube beams. CNT arrays act as both adhesive and conductive agents and impedance changes occurred as fast as 30 s (for whole entrapment and signaling processes). CNT-ECIS detected the cancer cells with the concentration as low as 4000 cells cm(-2) on its surface and a sensitivity of 1.7 × 10(-3)Ω cm(2). Time and cell efficiency factor (TEF and CEF) parameters were defined which describe the sensor's rapidness and resolution, respectively. TEF and CEF of CNT-ECIS were much higher than other cell based electrical biosensors which are compared in this paper.

  17. Dominant factors governing the rate capability of a TiO2 nanotube anode for high power lithium ion batteries.

    Science.gov (United States)

    Han, Hyungkyu; Song, Taeseup; Lee, Eung-Kwan; Devadoss, Anitha; Jeon, Yeryung; Ha, Jaehwan; Chung, Yong-Chae; Choi, Young-Min; Jung, Yeon-Gil; Paik, Ungyu

    2012-09-25

    Titanium dioxide (TiO(2)) is one of the most promising anode materials for lithium ion batteries due to low cost and structural stability during Li insertion/extraction. However, its poor rate capability limits its practical use. Although various approaches have been explored to overcome this problem, previous reports have mainly focused on the enhancement of both the electronic conductivity and the kinetic associated with lithium in the composite film of active material/conducting agent/binder. Here, we systematically explore the effect of the contact resistance between a current collector and a composite film of active material/conducting agent/binder on the rate capability of a TiO(2)-based electrode. The vertically aligned TiO(2) nanotubes arrays, directly grown on the current collector, with sealed cap and unsealed cap, and conventional randomly oriented TiO(2) nanotubes electrodes were prepared for this study. The vertically aligned TiO(2) nanotubes array electrode with unsealed cap showed superior performance with six times higher capacity at 10 C rate compared to conventional randomly oriented TiO(2) nanotubes electrode with 10 wt % conducting agent. On the basis of the detailed experimental results and associated theoretical analysis, we demonstrate that the reduction of the contact resistance between electrode and current collector plays an important role in improving the electronic conductivity of the overall electrode system.

  18. In situ polymerization and characterization of grafted poly (3,4-ethylenedioxythiophene)/multiwalled carbon nanotubes composite with high electrochemical performances

    International Nuclear Information System (INIS)

    Bai, Xiaoxia; Hu, Xiujie; Zhou, Shuyun; Yan, Jun; Sun, Chenghua; Chen, Ping; Li, Laifeng

    2013-01-01

    Graphical abstract: The homogeneously grafted PEDOT/MWCNTs containing numerous whorl fingerprint-like open ends endows with excellent electrochemical performances. Highlights: ► A ternary phase system with the surfactant AOT is utilized to efficiently solve the problem of the aggregation of MWCNTs. ► The homogenously grafted PEDOT/MWCNTs composite is synthesized by in situ chemical polymerization in the ternary phase system. ► The core–shell nanotubes contain many whorl fingerprint-like open ends that are greatly favorable for the transportation of the electrons and ions. ► The energy density of grafted PEDOT/MWCNTs has been enhanced by a factor of four comparing to that of native MWCNTs. ► The grafted PEDOT/MWCNTs composite manifests better cycle durability than both the constituents. - Abstract: The homogenously grafted composite of poly (3,4-ethylenedioxythiophene)/multiwalled carbon nanotubes (PEDOT/MWCNTs) is synthesized by in situ chemical polymerization in a ternary phase system. When carbon nanotubes are dispersed in this system containing sodium bis(2-ethylhexyl) sulfosuccinate (AOT), the surfactant AOT can efficiently hinter the aggregation of MWCNTs by absorbing and arranging regularly on the MWCNT surface. It is greatly advantageous to the stabilization of MWCNTs, which leads to the equally grafted composite. Its morphology was observed by scanning and transmission electron microscopes. Especially, the core–shell nanotubes contain many whorl fingerprint-like open ends that are efficiently favorable for the transportation of the electrons and ions. Such grafted PEDOT/MWCNTs composite nanotubes manifest enhanced electrochemical performances. We investigate the application of PEDOT/MWCNTs as a high-property supercapacitor and test its capacitive performance by cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance spectroscopy. The energy density of grafted composite, 11.3 Wh kg −1 , has been enhanced by a factor

  19. Glucose oxidase immobilization onto carbon nanotube networking

    International Nuclear Information System (INIS)

    Karachevtsev, V.A.; Glamazda, A.Yu.; Zarudnev, E.S.; Karachevtsev, M.V.; Leontiev, V.S.; Linnik, A.S.; Plokhotnichenko, A.M.; Stepanian, S.G.; Lytvyn, O.S.

    2012-01-01

    The efficient immobilization of GOX onto a carbon nanotube network through the molecular interface formed by PSE is carried out. This conclusion is based on the analysis of AFM images of the network with the adsorbed enzyme, whose globules locate mainly along a nanotube. The band corresponding to the high-frequency component of the G mode in the RR spectrum of the nanotube with adsorbed PSE is downshifted by 0.7 cm -1 relative to this band in the spectrum of pristine nanotubes. The analysis of the intensities of bands assigned to the RBM of nanotubes with adsorbed PSE in comparison with the spectrum of pristine SWNTs revealed the intensity transformation, which can be explained by a change of the resonance condition with variation of the laser energy. Thus, we concluded that PSE molecules create nanohybrids with SWNTs, which ensures the further enzyme immobilization. As the RR spectrum of an SWNT:PSE:GOX film does not essentially differ from SWNT:PSE ones, this indicates that the molecular interface (PSE) isolates the enzyme from nanotubes strongly enough. Our studies on the conductive properties of a single walled carbon nanotube network sprayed onto a quartz substrate from a solution of nanotubes in dichlorobenzene demonstrated that the I(U) dependence has nonlinear character. Most likely, the nonlinearity is related to Schottky barriers, which originate on the contact between nanotubes and the gold electrode, as well as between nanotubes with different conductivities. The deposition of bioorganic compounds (PSE and GOX) on the carbon nanotube network is accompanied by a decrease of their conductivity. Most probably, such a decrease is caused by adsorbed PSE molecules, which induce the appearance of scattering centers for charge carriers on the nanotube surface. The following GOX adsorption has practically no effect on the conductivity of the nanotube network that evidences the reliable isolation of the nanotube surface from the enzyme by means of the molecular

  20. Nickel cobaltite nanograss grown around porous carbon nanotube-wrapped stainless steel wire mesh as a flexible electrode for high-performance supercapacitor application

    International Nuclear Information System (INIS)

    Wu, Mao-Sung; Zheng, Zhi-Bin; Lai, Yu-Sheng; Jow, Jiin-Jiang

    2015-01-01

    Graphical abstract: Nickel cobaltite nanograss with bimodal pore size distribution is grown around the carbon nanotube-wrapped stainless steel wire mesh as a high capacitance and stable electrode for high-performance and flexible supercapacitors. - Highlights: • NiCo 2 O 4 nanograss with bimodal pore size distribution is hydrothermally prepared. • Carbon nanotubes (CNTs) wrap around stainless steel (SS) wire mesh as a scaffold. • NiCo 2 O 4 grown on CNT-wrapped SS mesh shows excellent capacitive performance. • Porous CNT layer allows for rapid transport of electron and electrolyte. - Abstract: Nickel cobaltite nanograss with bimodal pore size distribution (small and large mesopores) is grown on various electrode substrates by one-pot hydrothermal synthesis. The small pores (<5 nm) in the nanograss of individual nanorods contribute to large surface area, while the large pore channels (>20 nm) between nanorods offer fast transport paths for electrolyte. Carbon nanotubes (CNTs) with high electrical conductivity wrap around stainless steel (SS) wire mesh by electrophoresis as an electrode scaffold for supporting the nickel cobaltite nanograss. This unique electrode configuration turns out to have great benefits for the development of supercapacitors. The specific capacitance of nickel cobaltite grown around CNT-wrapped SS wire mesh reaches 1223 and 1070 F g −1 at current densities of 1 and 50 A g −1 , respectively. CNT-wrapped SS wire mesh affords porous and conductive networks underneath the nanograss for rapid transport of electron and electrolyte. Flexible CNTs connect the nanorods to mitigate the contact resistance and the volume expansion during cycling test. Thus, this tailored electrode can significantly reduce the ohmic resistance, charge-transfer resistance, and diffusive impedance, leading to high specific capacitance, prominent rate performance, and good cycle-life stability.

  1. Template-based fabrication of nanowire-nanotube hybrid arrays

    International Nuclear Information System (INIS)

    Ye Zuxin; Liu Haidong; Schultz, Isabel; Wu Wenhao; Naugle, D G; Lyuksyutov, I

    2008-01-01

    The fabrication and structure characterization of ordered nanowire-nanotube hybrid arrays embedded in porous anodic aluminum oxide (AAO) membranes are reported. Arrays of TiO 2 nanotubes were first deposited into the pores of AAO membranes by a sol-gel technique. Co nanowires were then electrochemically deposited into the TiO 2 nanotubes to form the nanowire-nanotube hybrid arrays. Scanning electron microscopy and transmission electron microscopy measurements showed a high nanowire filling factor and a clean interface between the Co nanowire and the TiO 2 nanotube. Application of these hybrids to the fabrication of ordered nanowire arrays with highly controllable geometric parameters is discussed

  2. Nano assembly of N-doped graphene quantum dots anchored Fe3O4/halloysite nanotubes for high performance supercapacitor

    International Nuclear Information System (INIS)

    Ganganboina, Akhilesh Babu; Chowdhury, Ankan Dutta; Doong, Ruey-an

    2017-01-01

    Highlights: •Halloysite coated Fe 3 O 4 is served as the framework for supporting graphene quantum dots. •GQDs can be well distributed onto Fe 3 O 4 /HNTs to prevent structural failure. •High specific capacitance of 418 F g −1 in 1 M Na 2 SO 4 neutral electrolyte is observed. •The composites show excellent electrochemical performance with energy density of 10.4–29.0 Wh kg −1 . -- Abstract: The development of robust and low cost electrode materials with superior electrochemical properties has been a subject of focus on energy storage devices. Herein, the development of N-doped graphene quantum dots (N-GQDs) deposited on Fe 3 O 4 -halloysite nanotubes (Fe 3 O 4 -HNTs) as active anode materials has been established for supercapacitor applications. The Fe 3 O 4 nanoparticles synthesised by coprecipitation have been in-situ deposited on HNT surfaces following by the coating of (3-aminopropyl)-triexthoxysilane to anchor 4–10 nm N-GQDs via the formation of amide linkage. The N-GQD@Fe 3 O 4 -HNTs exhibits a high specific capacitance of 418 F g −1 and maintains good rate capability in neutral electrolyte solutions. In addition, the anode materials show excellent electrochemical performance with energy and power densities of 10.4–29 W h kg −1 and 0.25–5.2 kW kg −1 , respectively. Such excellent electrochemical features can be attributed to the synergistic contribution from individual components. The Fe 3 O 4 -HNTs provide 1-dimensional matrix to shorten the diffusion path of electrons and electrolyte ions as well as to absorb the mechanical stress during cycling along with excess sites for charge storage, while N-GQDs offer abundantly accessible electroactive sites for rapid electrons and electrolyte ions transport as well as enhance electrical conductivity of Fe 3 O 4 -HNTs. Results obtained in this study clearly demonstrate that metal oxide-HNTs are promising support to anchor N-GQDs nanomaterials as the high performance anode materials for next

  3. Supported noble metals on hydrogen-treated TiO2 nanotube arrays as highly ordered electrodes for fuel cells.

    Science.gov (United States)

    Zhang, Changkun; Yu, Hongmei; Li, Yongkun; Gao, Yuan; Zhao, Yun; Song, Wei; Shao, Zhigang; Yi, Baolian

    2013-04-01

    Hydrogen-treated TiO2 nanotube (H-TNT) arrays serve as highly ordered nanostructured electrode supports, which are able to significantly improve the electrochemical performance and durability of fuel cells. The electrical conductivity of H-TNTs increases by approximately one order of magnitude in comparison to air-treated TNTs. The increase in the number of oxygen vacancies and hydroxyl groups on the H-TNTs help to anchor a greater number of Pt atoms during Pt electrodeposition. The H-TNTs are pretreated by using a successive ion adsorption and reaction (SIAR) method that enhances the loading and dispersion of Pt catalysts when electrodeposited. In the SIAR method a Pd activator can be used to provide uniform nucleation sites for Pt and leads to increased Pt loading on the H-TNTs. Furthermore, fabricated Pt nanoparticles with a diameter of 3.4 nm are located uniformly around the pretreated H-TNT support. The as-prepared and highly ordered electrodes exhibit excellent stability during accelerated durability tests, particularly for the H-TNT-loaded Pt catalysts that have been annealed in ultrahigh purity H2 for a second time. There is minimal decrease in the electrochemical surface area of the as-prepared electrode after 1000 cycles compared to a 68 % decrease for the commercial JM 20 % Pt/C electrode after 800 cycles. X-ray photoelectron spectroscopy shows that after the H-TNT-loaded Pt catalysts are annealed in H2 for the second time, the strong metal-support interaction between the H-TNTs and the Pt catalysts enhances the electrochemical stability of the electrodes. Fuel-cell testing shows that the power density reaches a maximum of 500 mWcm(-2) when this highly ordered electrode is used as the anode. When used as the cathode in a fuel cell with extra-low Pt loading, the new electrode generates a specific power density of 2.68 kWg(Pt) (-1) . It is indicated that H-TNT arrays, which have highly ordered nanostructures, could be used as ordered electrode supports

  4. In Situ High-Resolution Transmission Electron Microscopy (TEM) Observation of Sn Nanoparticles on SnO2 Nanotubes Under Lithiation.

    Science.gov (United States)

    Cheong, Jun Young; Chang, Joon Ha; Kim, Sung Joo; Kim, Chanhoon; Seo, Hyeon Kook; Shin, Jae Won; Yuk, Jong Min; Lee, Jeong Yong; Kim, Il-Doo

    2017-12-01

    We trace Sn nanoparticles (NPs) produced from SnO2 nanotubes (NTs) during lithiation initialized by high energy e-beam irradiation. The growth dynamics of Sn NPs is visualized in liquid electrolytes by graphene liquid cell transmission electron microscopy. The observation reveals that Sn NPs grow on the surface of SnO2 NTs via coalescence and the final shape of agglomerated NPs is governed by surface energy of the Sn NPs and the interfacial energy between Sn NPs and SnO2 NTs. Our result will likely benefit more rational material design of the ideal interface for facile ion insertion.

  5. Silicon-Carbon Nanotube Coaxial Sponge as Li-Ion Anodes with High Areal Capacity

    KAUST Repository

    Hu, Liangbing; Wu, Hui; Gao, Yifan; Cao, Anyuan; Li, Hongbian; McDough, James; Xie, Xing; Zhou, Min; Cui, Yi

    2011-01-01

    Highly porous, conductive Si-CNT sponge-like structures with a large areal mass loading are demonstrated as effective Li-ion battery anode materials. Nano-pore formation and growth in the Si shell has been identified as the primary failure mode

  6. A Photodetector Based on p-Si/n-ZnO Nanotube Heterojunctions with High Ultraviolet Responsivity

    KAUST Repository

    Flemban, Tahani H.; Haque, Mohammed; Ajia, Idris A.; Alwadai, Norah Mohammed Mosfer; Mitra, Somak; Wu, Tao; Roqan, Iman S.

    2017-01-01

    properties on a p-type Si(100) substrate are successfully fabricated by pulsed laser deposition (PLD) to produce a UV PD with high responsivity, for the first time. We measure the current–voltage characteristics of the device under dark and illuminated

  7. Direct growth of vanadium nitride nanosheets on carbon nanotube fibers as novel negative electrodes for high-energy-density wearable fiber-shaped asymmetric supercapacitors

    Science.gov (United States)

    Guo, Jiabin; Zhang, Qichong; Sun, Juan; Li, Chaowei; Zhao, Jingxin; Zhou, Zhenyu; He, Bing; Wang, Xiaona; Man, Ping; Li, Qiulong; Zhang, Jun; Xie, Liyan; Li, Mingxing; Yao, Yagang

    2018-04-01

    Significant efforts have been recently devoted to constructing high-performance fiber-shaped asymmetric supercapacitors. However, it is still a paramount challenge to develop high-energy-density fiber-shaped asymmetric supercapacitors for practical applications in portable and wearable electronics. This work reports a simple and efficient method to directly grow vanadium nitride nanosheets on carbon nanotube fibers as advanced negative electrodes with a high specific capacitance of 188 F/cm3 (564 mF/cm2). Taking advantage of their attractive structure, we successfully fabricated a fiber-shaped asymmetric supercapacitor device with a maximum operating voltage of 1.6 V by assembling the vanadium nitride/carbon nanotube fiber negative electrode with the Zinc-Nickel-Cobalt ternary oxides nanowire arrays positive electrode. Due to the excellent synergistic effects between positive and negative electrodes, a remarkable specific capacitance of 50 F/cm3 (150 mF/cm2) and an outstanding energy density of 17.78 mWh/cm3 (53.33 μWh/cm2) for our fiber-shaped asymmetric supercapacitor can be achieved. Furthermore, the as-assembled fiber-shaped asymmetric supercapacitor device has excellent mechanical flexibility in that 91% of the capacitance retained after bending 90° for 3000 times. Thus, this work exploits a pathway to construct high-energy-density fiber-shaped asymmetric supercapacitor for next-generation portable and wearable electronics.

  8. High Efficiency Flexible Battery Based on Graphene-carbon Nanotube Hybrid Structure

    Science.gov (United States)

    2015-02-26

    Choi, Carbon 77 1065(2014) 2. Hierarchical NiCo2O4@nickel-sulfide nanoplate arrays for high-performance supercapacitors , Chu Q, Wang W, Wang X...Graphene:Synthesis and Applications, CRC Press ISBN-10: 1439861870 | ISBN-13: 978-1439861875 | Publication Date: October 11, 2011 Handbook of Nanomaterials ...Properties, Carbon Nanomaterials : a review, Nitin Choudhary, Sookhyun Hwang, Wonbong Choi, Springer (2013) 15. Santanu Das and Wonbong Choi, Graphene

  9. Highly Conductive, Transparent Flexible Films Based on Metal Nanoparticle-Carbon Nanotube Composites

    Directory of Open Access Journals (Sweden)

    Wen-Yin Ko

    2013-01-01

    Full Text Available Metallic nanoparticles decorated on MWCNTs based transparent conducting thin films (TCFs show a cheap and efficient option for the applications in touch screens and the replacement of the ITO film because of their interesting properties of electrical conductivity, mechanical property, chemical inertness, and other unique properties, which may not be accessible by their individual components. However, a great challenge that always remains is to develop effective ways to prepare junctions between metallic nanoparticles and MWCNTs for the improvement of high-energy barriers, high contact resistances, and weak interactions which could lead to the formation of poor conducting pathways and result in the CNT-based devices with low mechanical flexibility. Herein, we not only discuss recent progress in the preparation of MNP-CNT flexible TCFs but also describe our research studies in the relevant areas. Our result demonstrated that the MNP-CNT flexible TCFs we prepared could achieve a highly electrical conductivity with the sheet resistance of ~100 ohm/sq with ~80% transmittance at 550 nm even after being bent 500 times. This electrical conductivity is much superior to the performances of other MWCNT-based transparent flexible films, making it favorable for next-generation flexible touch screens and optoelectronic devices.

  10. Silicon-Carbon Nanotube Coaxial Sponge as Li-Ion Anodes with High Areal Capacity

    KAUST Repository

    Hu, Liangbing

    2011-07-01

    Highly porous, conductive Si-CNT sponge-like structures with a large areal mass loading are demonstrated as effective Li-ion battery anode materials. Nano-pore formation and growth in the Si shell has been identified as the primary failure mode of the Si-CNT sponge anode, and the formation of such nanopores can be minimized by tuning the cutoff voltages. In conjunction with experiments, a theoretical analysis was carried out to explain the pore formation mechanism. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. High content of pyridinic- and pyrrolic-nitrogen-modified carbon nanotubes derived from blood biomass for the electrocatalysis of oxygen reduction reaction in alkaline medium

    International Nuclear Information System (INIS)

    Zheng, Jie; Guo, Chaozhong; Chen, Chunyan; Fan, Mingzhi; Gong, Jianping; Zhang, Yanfang; Zhao, Tianxin; Sun, Yuelin; Xu, Xiaofan; Li, Mengmeng; Wang, Ran; Luo, Zhongli; Chen, Changguo

    2015-01-01

    Graphical abstract: Display Omitted -- Highlights: •An ORR electrocatalyst was fabricated from blood biomass and carbon nanotube. •The N-CNT catalyst exhibits good ORR activity, methanol resistance and stability. •The pyrolysis process produces high contents of pyridinic and pyrrolic N species. •The pyridinic-N group may play more important role in the active sites for ORR. -- Abstract: Here we present a facile synthetic route to design nitrogen-doped nanostructured carbon-based electrocatalyst for oxygen reduction reaction (ORR) by the copyrolysis of blood biomass from pig and carbon nanotubes (CNTs) at high temperatures. The nitrogen-doped CNTs obtained at 800 °C not only results in excellent ORR activity with four-electron transfer selectivity in alkaline medium, but also exhibits superior methanol-tolerant property and long-term stability. It is confirmed that high-temperature pyrolysis processes can facilitate to produce higher contents of pyridinic- and pyrrolic-N binding groups in electrocatalysts, contributing to the enhancement of ORR performance in terms of onset potential, half-wave potential, and limited current density. We also propose that the planar-N configuration may be the active site that is responsible for the improved ORR electrocatalytic performance. The straight-forward and cheap synthesis of the active and stable electrocatalyst makes it a promising candidate for electrochemical power sources such as fuel cells or metal-air batteries

  12. Polyaniline/single-wall carbon nanotube (PANI/SWCNT) composites for high performance supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, Vinay; Miura, Norio [Art, Science and Technology Center for Cooperative Research, Kyushu University, Kasuga-shi, Fukuoka 816-8580 (Japan)

    2006-12-01

    PANI/SWCNT composites were prepared by electrochemical polymerisation of polyaniline onto SWCNTs and their capacitive performance was evaluated by means of cyclic voltammetry and charge-discharge cycling in 1M H{sub 2}SO{sub 4} electrolyte. The PANI/SWCNT composites single electrode showed much higher specific capacitance, specific energy and specific power than pure PANI and SWCNTs. The highest specific capacitance, specific power and specific energy values of 485F/g, 228Wh/kg and 2250W/kg were observed for 73wt.% PANI deposited onto SWCNTs. PANI/SWCNT composites also showed long cyclic stability. Based upon the variations in the surface morphologies and specific capacitance of the composite, a mechanism is proposed to explain enhancement in the capacitive characteristics. The PANI/SWCNT composites have demonstrated the potential as excellent electrode materials for application in high performance supercapacitors. (author)

  13. Water surface assisted synthesis of large-scale carbon nanotube film for high-performance and stretchable supercapacitors.

    Science.gov (United States)

    Yu, Minghao; Zhang, Yangfan; Zeng, Yinxiang; Balogun, Muhammad-Sadeeq; Mai, Kancheng; Zhang, Zishou; Lu, Xihong; Tong, Yexiang

    2014-07-16

    A kind of multiwalled carbon-nanotube (MWCNT)/polydimethylsiloxane (PDMS) film with excellent conductivity and mechanical properties is developed using a facile and large-scale water surface assisted synthesis method. The film can act as a conductive support for electrochemically active PANI nano fibers. A device based on these PANI/MWCNT/PDMS electrodes shows good and stable capacitive behavior, even under static and dynamic stretching conditions. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Highly Stable and Flexible Pressure Sensors with Modified Multi-Walled Carbon Nanotube/Polymer Composites for Human Monitoring.

    Science.gov (United States)

    He, Yin; Ming, Yue; Li, Wei; Li, Yafang; Wu, Maoqi; Song, Jinzhong; Li, Xiaojiu; Liu, Hao

    2018-04-26

    A facile method for preparing an easy processing, repeatable and flexible pressure sensor was presented via the synthesis of modified multi-walled carbon nanotubes (m-MWNTs) and polyurethane (PU) films. The surface modification of multi-walled carbon nanotubes (MWNTs) simultaneously used a silane coupling agent (KH550) and sodium dodecyl benzene sulfonate (SDBS) to improve the dispersibility and compatibility of the MWNTs in a polymer matrix. The electrical property and piezoresistive behavior of the m-MWNT/PU composites were compared with raw multi-walled carbon nanotube (raw MWNT)/PU composites. Under linear uniaxial pressure, the m-MWNT/PU composite exhibited 4.282%kPa −1 sensitivity within the pressure of 1 kPa. The nonlinear error, hysteresis error and repeatability error of the piezoresistivity of m-MWNT/PU decreased 9%, 16.72% and 54.95% relative to raw MWNT/PU respectively. Therefore, the piezoresistive response of m-MWNT/PU had better stability than that of raw MWNT/PU composites. The m-MWNT/PU sensors could be utilized in wearable devices for body movement detection, monitoring of respiration and pressure detection in garments.

  15. Decorating Mg/Fe oxide nanotubes with nitrogen-doped carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Cao Yong, E-mail: caoyangel@126.com [Institute of Environment and Municipal Engineering, North China Institute of Water Conservancy and Hydroelectric Power, Zhengzhou 450011 (China); Jiao Qingze, E-mail: jiaoqz@bit.edu.cn [School of Chemical Engineering and the Environment, Beijing Institute of Technology, Beijing 100081 (China); Zhao Yun [School of Chemical Engineering and the Environment, Beijing Institute of Technology, Beijing 100081 (China); Dong Yingchao [Materials and Surface Science Institute (MSSI), University of Limerick, Limerick (Ireland)

    2011-09-22

    Graphical abstract: Highlights: > Mg/Fe oxide nanotubes arrayed parallel to each other were prepared by an AAO template method. > The Mg/Fe oxide nanotubes decorated with CN{sub x} were realized by CVD of ethylenediamine on the outer surface of oxide nanotubes. > The magnetic properties of Mg/Fe oxide nanotubes were highly improved after being decorated. - Abstract: Mg/Fe oxide nanotubes decorated with nitrogen-doped carbon nanotubes (CN{sub x}) were fabricated by catalytic chemical vapor deposition of ethylenediamine on the outer surface of oxide nanotubes. Mg/Fe oxide nanotubes were prepared using a 3:1 molar precursor solution of Mg(NO{sub 3}){sub 2} and Fe(NO{sub 3}){sub 3} and anodic aluminum oxide as the substrate. The obtained samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and vibrating sample magnetometer (VSM). The XRD pattern shows that the oxide nanotubes are made up of MgO and Fe{sub 2}O{sub 3}. TEM and SEM observations indicate the oxide nanotubes are arrayed roughly parallel to each other, and the outer surface of oxide nanotubes are decorated with CN{sub x}. XPS results show the nitrogen-doped level in CN{sub x} is about 7.3 at.%. Magnetic measurements with VSM demonstrate the saturated magnetization, remanence and coercivity of oxide nanotubes are obvious improved after being decorated with CN{sub x}.

  16. Hydroxyapatite electrodeposition on anodized titanium nanotubes for orthopedic applications

    Science.gov (United States)

    Parcharoen, Yardnapar; Kajitvichyanukul, Puangrat; Sirivisoot, Sirinrath; Termsuksawad, Preecha

    2014-08-01

    Nanotubes modification for orthopedic implants has shown interesting biological performances (such as improving cell adhesion, cell differentiation, and enhancing osseointegration). The purpose of this study is to investigate effect of titanium dioxide (TiO2) nanotube feature on performance of hydroxyapatite-coated titanium (Ti) bone implants. TiO2 nanotubes were prepared by anodization using ammonium fluoride electrolyte (NH4F) with and without modifiers (PEG400 and Glycerol) at various potential forms, and times. After anodization, the nanotubes were subsequently annealed. TiO2 nanotubes were characterized by scanning electron microscope and X-ray diffractometer. The amorphous to anatase transformation due to annealing was observed. Smooth and highly organized TiO2 nanotubes were found when high viscous electrolyte, NH4F in glycerol, was used. Negative voltage (-4 V) during anodization was confirmed to increase nanotube thickness. Length of the TiO2 nanotubes was significantly increased by times. The TiO2 nanotube was electrodeposited with hydroxyapatite (HA) and its adhesion was estimated by adhesive tape test. The result showed that nanotubes with the tube length of 560 nm showed excellent adhesion. The coated HA were tested for biological test by live/dead cell straining. HA coated on TiO2 nanotubes showed higher cells density, higher live cells, and more spreading of MC3T3-E1 cells than that growing on titanium plate surface.

  17. In situ growth of NiCo2S4 nanotube arrays on Ni foam for supercapacitors: Maximizing utilization efficiency at high mass loading to achieve ultrahigh areal pseudocapacitance

    Science.gov (United States)

    Chen, Haichao; Jiang, Jianjun; Zhang, Li; Xia, Dandan; Zhao, Yuandong; Guo, Danqing; Qi, Tong; Wan, Houzhao

    2014-05-01

    Self-standing NiCo2S4 nanotube arrays have been in situ grown on Ni foam by the anion-exchange reaction and directly used as the electrode for supercapacitors. The NiCo2S4 nanotube in the arrays effectively reduces the inactive material and increases the electroactive surface area because of the ultrathin wall, which is quite competent to achieve high utilization efficiency at high electroactive materials mass loading. The NiCo2S4 nanotube arrays hybrid electrode exhibits an ultrahigh specific capacitance of 14.39 F cm-2 at 5 mA cm-2 with excellent rate performance (67.7% retention for current increases 30 times) and cycling stability (92% retention after 5000 cycles) at a high mass loading of 6 mg cm-2. High areal capacitance (4.68 F cm-2 at 10 mA cm-2), high energy density (31.5 Wh kg-1 at 156.6 W kg-1) and high power density (2348.5 W kg-1 at 16.6 Wh kg-1) can be achieved by assembling asymmetric supercapacitor with reduced graphene oxide at a total active material mass loading as high as 49.5 mg. This work demonstrates that NiCo2S4 nanotube arrays structure is a superior electroactive material for high-performance supercapacitors even at a mass loading of potential application-specific scale.

  18. Tantalum electrodes modified with well-aligned carbon nanotube-Au nanoparticles: application to the highly sensitive electrochemical determination of cefazolin.

    Science.gov (United States)

    Fayazfar, Haniyeh; Afshar, Abdollah; Dolati, Abolghasem

    2014-07-01

    Carbon nanotube/nanoparticle hybrid materials have been proven to exhibit high electrocatalytic activity suggesting broad potential applications in the field of electroanalysis. For the first time, modification of Ta electrode with aligned multi-walled carbon nanotubes/Au nanoparticles introduced for the sensitive determination of the antibiotic drug, cefazolin (CFZ). The electrochemical response characteristics of the modified electrode toward CFZ were investigated by means of cyclic and linear sweep voltammetry. The modified electrode showed an efficient catalytic activity for the reduction of CFZ, leading to a remarkable decrease in reduction overpotential and a significant increase of peak current. Under optimum conditions, the highly sensitive modified electrode showed a wide linear range from 50 pM to 50 μM with a sufficiently low detection limit of 1 ± 0.01 pM (S/N = 3). The results indicated that the prepared electrode presents suitable characteristics in terms of sensitivity (458.2 ± 2.6 μAcm(-2)/μM), accuracy, repeatability (RSD of 1.8 %), reproducibility (RSD of 2.9 %), stability (14 days), and good catalytic activity in physiological conditions. The method was successfully applied for accurate determination of trace amounts of CFZ in pharmaceutical and clinical preparations without the necessity for samples pretreatment or any time-consuming extraction or evaporation steps prior to the analysis.

  19. DNA-assisted assembly of carbon nanotubes and MnO2 nanospheres as electrodes for high-performance asymmetric supercapacitors.

    Science.gov (United States)

    Guo, Chun Xian; Chitre, Amey Anil; Lu, Xianmao

    2014-03-14

    A DNA-assisted assembly approach is developed to fabricate a capacitor-type electrode material, DNA-functionalized carbon nanotubes (CNTs@DNA), and a battery-type electrode material, DNA@CNTs-bridged MnO2 spheres (CNTs@DNA-MnO2), for asymmetric supercapacitors. An energy density of 11.6 W h kg(-1) is achieved at a power density of 185.5 W kg(-1) with a high MnO2 mass loading of 4.2 mg cm(-2). It is found that DNA assembly plays a critical role in the enhanced supercapacitor performance. This is because while DNA molecules functionalize carbon nanotubes (CNTs) via π-π stacking, their hydrophilic sugar-phosphate backbones also promote the dispersion of CNTs. The resultant CNTs@DNA chains can link multiple MnO2 spheres to form a networked architecture that facilitates charge transfer and effective MnO2 utilization. The improved performance of the asymmetric supercapacitors indicates that DNA-assisted assembly offers a promising approach to the fabrication of high-performance energy storage devices.

  20. Carbon nanotube network-silicon oxide non-volatile switches.

    Science.gov (United States)

    Liao, Albert D; Araujo, Paulo T; Xu, Runjie; Dresselhaus, Mildred S

    2014-12-08

    The integration of carbon nanotubes with silicon is important for their incorporation into next-generation nano-electronics. Here we demonstrate a non-volatile switch that utilizes carbon nanotube networks to electrically contact a conductive nanocrystal silicon filament in silicon dioxide. We form this device by biasing a nanotube network until it physically breaks in vacuum, creating the conductive silicon filament connected across a small nano-gap. From Raman spectroscopy, we observe coalescence of nanotubes during breakdown, which stabilizes the system to form very small gaps in the network~15 nm. We report that carbon nanotubes themselves are involved in switching the device to a high resistive state. Calculations reveal that this switching event occurs at ~600 °C, the temperature associated with the oxidation of nanotubes. Therefore, we propose that, in switching to a resistive state, the nanotube oxidizes by extracting oxygen from the substrate.

  1. Co(OH)2/RGO/NiO sandwich-structured nanotube arrays with special surface and synergistic effects as high-performance positive electrodes for asymmetric supercapacitors

    Science.gov (United States)

    Xu, Han; Zhang, Chi; Zhou, Wen; Li, Gao-Ren

    2015-10-01

    High power density, high energy density and excellent cycling stability are the main requirements for high-performance supercapacitors (SCs) that will be widely used for portable consumer electronics and hybrid electric vehicles. Here we investigate novel types of hybrid Co(OH)2/reduced graphene oxide (RGO)/NiO sandwich-structured nanotube arrays (SNTAs) as positive electrodes for asymmetric supercapacitors (ASCs). The synthesized Co(OH)2/RGO/NiO SNTAs exhibit a significantly improved specific capacity (~1470 F g-1 at 5 mV s-1) and excellent cycling stability with ~98% Csp retention after 10 000 cycles because of the fast transport and short diffusion paths for electroactive species, the high utilization rate of electrode materials, and special synergistic effects among Co(OH)2, RGO, and NiO. The high-performance ASCs are assembled using Co(OH)2/RGO/NiO SNTAs as positive electrodes and active carbon (AC) as negative electrodes, and they exhibit a high energy density (115 Wh kg-1), a high power density (27.5 kW kg-1) and an excellent cycling stability (less 5% Csp loss after 10 000 cycles). This study shows an important breakthrough in the design and fabrication of multi-walled hybrid nanotube arrays as positive electrodes for ASCs.High power density, high energy density and excellent cycling stability are the main requirements for high-performance supercapacitors (SCs) that will be widely used for portable consumer electronics and hybrid electric vehicles. Here we investigate novel types of hybrid Co(OH)2/reduced graphene oxide (RGO)/NiO sandwich-structured nanotube arrays (SNTAs) as positive electrodes for asymmetric supercapacitors (ASCs). The synthesized Co(OH)2/RGO/NiO SNTAs exhibit a significantly improved specific capacity (~1470 F g-1 at 5 mV s-1) and excellent cycling stability with ~98% Csp retention after 10 000 cycles because of the fast transport and short diffusion paths for electroactive species, the high utilization rate of electrode materials, and

  2. 3D well-interconnected NiO–graphene–carbon nanotube nanohybrids as high-performance anode materials for Li-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Zhifeng; Zhang, Xia; You, Xiaolong; Zhang, Mengyuan; Walle, Maru Dessie [Central South University, College of Chemistry and Chemical Engineering (China); Wang, Juan [State Grid Information & Telecommunication Group Co., Ltd. (China); Li, Yajuan, E-mail: yajuanli@csu.edu.cn; Liu, You-Nian [Central South University, College of Chemistry and Chemical Engineering (China)

    2016-08-15

    3D carbon scaffold built from carbon nanotubes (CNTs) and graphene exhibits the synergistic effects in electronic conductivity and buffers the structural strain of materials. In this paper, NiO–graphene–carbon nanotubes (NiO–G–CNTs) nanohybrids were prepared via a facile hydrothermal–thermal decomposition process. The as-prepared ternary component nanohybrids exhibit high reversible specific capacity, improved cycling stability, and excellent rate capability, compared to those of NiO–graphene hybrids and pure NiO. The NiO–G–CNT electrode reveals a specific capacity of 858.1 mA h g{sup −1} after 50 cycles at a current density of 100 mA g{sup −1}. At a higher current density of 1000 mA g{sup −1}, it still reveals a specific capacity of 676 mA h g{sup −1} after 40 cycles. This outstanding electrochemical performance is attributed to its special 3D network structures, where the NiO nanoparticles are well distributed on the surface of graphene sheets, with the CNTs interwoven between individual graphene sheets. This special structure effectively prevents the restacking of graphene sheets and affords an easy route for the transport of electrons and ions.Graphical abstract.

  3. A strategy for achieving low percolation and high electrical conductivity in melt-blended polycarbonate (PC/multiwall carbon nanotube (MWCNT nanocomposites: Electrical and thermo-mechanical properties

    Directory of Open Access Journals (Sweden)

    B. B. Khatua

    2013-06-01

    Full Text Available In this work, polycarbonate (PC/multiwall carbon nanotube (MWCNT nanocomposites were prepared by simple melt mixing at a temperature (~350°C well above the processing temperature of PC, followed by compression molding, that exhibited percolation threshold as low as of 0.11 wt% and high electrical conductivity of 1.38x10–3 S•cm–1 at only 0.5 wt% MWCNT loading. Due to the lower interfacial energy between MWCNT and PC, the carbon nanotubes are excellently dispersed and formed continuous conductive network structure throughout the host polymer. AC electrical conductivity and dielectric permittivity of PC/MWCNT nanocomposites were characterized in a broad frequency range, 101–107 Hz. Low percolation threshold (pc of 0.11 wt% and the critical exponent (t of ~3.38 was resulted from scaling law equation. The linear plot of logσDC vs. p–1/3 supported the presence of tunneling conduction among MWCNTs. The thermal property and storage modulus of PC were increased with the incorporation of little amount of MWCNTs. Transmission electron microscopy (TEM and field emission scanning electron microscopy (FESEM confirmed the homogeneous dispersion and distribution of MWCNTs throughout the matrix phase.

  4. A Universal Strategy for Hollow Metal Oxide Nanoparticles Encapsulated into B/N Co-Doped Graphitic Nanotubes as High-Performance Lithium-Ion Battery Anodes.

    Science.gov (United States)

    Tabassum, Hassina; Zou, Ruqiang; Mahmood, Asif; Liang, Zibin; Wang, Qingfei; Zhang, Hao; Gao, Song; Qu, Chong; Guo, Wenhan; Guo, Shaojun

    2018-02-01

    Yolk-shell nanostructures have received great attention for boosting the performance of lithium-ion batteries because of their obvious advantages in solving the problems associated with large volume change, low conductivity, and short diffusion path for Li + ion transport. A universal strategy for making hollow transition metal oxide (TMO) nanoparticles (NPs) encapsulated into B, N co-doped graphitic nanotubes (TMO@BNG (TMO = CoO, Ni 2 O 3 , Mn 3 O 4 ) through combining pyrolysis with an oxidation method is reported herein. The as-made TMO@BNG exhibits the TMO-dependent lithium-ion storage ability, in which CoO@BNG nanotubes exhibit highest lithium-ion storage capacity of 1554 mA h g -1 at the current density of 96 mA g -1 , good rate ability (410 mA h g -1 at 1.75 A g -1 ), and high stability (almost 96% storage capacity retention after 480 cycles). The present work highlights the importance of introducing hollow TMO NPs with thin wall into BNG with large surface area for boosting LIBs in the terms of storage capacity, rate capability, and cycling stability. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Highly enhanced electrochemical activity of Ni foam electrodes decorated with nitrogen-doped carbon nanotubes for non-aqueous redox flow batteries

    Science.gov (United States)

    Lee, Jungkuk; Park, Min-Sik; Kim, Ki Jae

    2017-02-01

    Nitrogen-doped carbon nanotubes (NCNTs) are directly grown on the surface of a three-dimensional (3D) Ni foam substrate by floating catalytic chemical vapor deposition (FCCVD). The electrochemical properties of the 3D NCNT-Ni foam are thoroughly examined as a potential electrode for non-aqueous redox flow batteries (RFBs). During synthesis, nitrogen atoms can be successfully doped onto the carbon nanotube (CNT) lattices by forming an abundance of nitrogen-based functional groups. The 3D NCNT-Ni foam electrode exhibits excellent electrochemical activities toward the redox reactions of [Fe (bpy)3]2+/3+ (in anolyte) and [Co(bpy)3]+/2+ (in catholyte), which are mainly attributed to the hierarchical 3D structure of the NCNT-Ni foam electrode and the catalytic effect of nitrogen atoms doped onto the CNTs; this leads to faster mass transfer and charge transfer during operation. As a result, the RFB cell assembled with 3D NCNT-Ni foam electrodes exhibits a high energy efficiency of 80.4% in the first cycle; this performance is maintained up to the 50th cycle without efficiency loss.

  6. A bamboo-inspired hierarchical nanoarchitecture of Ag/CuO/TiO_2 nanotube array for highly photocatalytic degradation of 2,4-dinitrophenol

    International Nuclear Information System (INIS)

    Zhang, Xuhong; Wang, Longlu; Liu, Chengbin; Ding, Yangbin; Zhang, Shuqu; Zeng, Yunxiong; Liu, Yutang; Luo, Shenglian

    2016-01-01

    Highlights: • Bamboo-like architecture of ternary photocatalyst. • High simulated solar light photocatalytic activity. • Integration of p-n heterojunction and Schottky junction. • Excellent stable recycling performance. - Abstract: The optimized geometrical configuration of muitiple active materials into hierarchical nanoarchitecture is essential for the creation of photocatalytic degradation system that can mimic natural photosynthesis. A bamboo-like architecture, CuO nanosheets and Ag nanoparticles co-decorated TiO_2 nanotube arrays (Ag/CuO/TiO_2), was fabricated by using simple solution-immersion and electrodeposition process. Under simulated solar light irradiation, the 2,4-dinitrophenol (2,4-DNP) photocatalytic degradation rate over Ag/CuO/TiO_2 was about 2.0, 1.5 and 1.2 times that over TiO_2 nanotubes, CuO/TiO_2 and Ag/TiO_2, respectively. The enhanced photocatalytic activity of ternary Ag/CuO/TiO_2 photocatalyst was ascribed to improved light absorption, reduced carrier recombination and more exposed active sites. Moreover, the excellent stability and reliability of the Ag/CuO/TiO_2 photocatalyst demonstrated a promising application for organic pollutant removal from water.

  7. A bamboo-inspired hierarchical nanoarchitecture of Ag/CuO/TiO{sub 2} nanotube array for highly photocatalytic degradation of 2,4-dinitrophenol

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xuhong; Wang, Longlu [State Key Laboratory of Chemo/Biosensing and Chemometrics, Hunan University, Changsha 410082 (China); Liu, Chengbin, E-mail: chem_cbliu@hnu.edu.cn [State Key Laboratory of Chemo/Biosensing and Chemometrics, Hunan University, Changsha 410082 (China); Ding, Yangbin; Zhang, Shuqu; Zeng, Yunxiong [State Key Laboratory of Chemo/Biosensing and Chemometrics, Hunan University, Changsha 410082 (China); Liu, Yutang, E-mail: liuyutang@126.com [Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082 (China); Luo, Shenglian [State Key Laboratory of Chemo/Biosensing and Chemometrics, Hunan University, Changsha 410082 (China)

    2016-08-05

    Highlights: • Bamboo-like architecture of ternary photocatalyst. • High simulated solar light photocatalytic activity. • Integration of p-n heterojunction and Schottky junction. • Excellent stable recycling performance. - Abstract: The optimized geometrical configuration of muitiple active materials into hierarchical nanoarchitecture is essential for the creation of photocatalytic degradation system that can mimic natural photosynthesis. A bamboo-like architecture, CuO nanosheets and Ag nanoparticles co-decorated TiO{sub 2} nanotube arrays (Ag/CuO/TiO{sub 2}), was fabricated by using simple solution-immersion and electrodeposition process. Under simulated solar light irradiation, the 2,4-dinitrophenol (2,4-DNP) photocatalytic degradation rate over Ag/CuO/TiO{sub 2} was about 2.0, 1.5 and 1.2 times that over TiO{sub 2} nanotubes, CuO/TiO{sub 2} and Ag/TiO{sub 2}, respectively. The enhanced photocatalytic activity of ternary Ag/CuO/TiO{sub 2} photocatalyst was ascribed to improved light absorption, reduced carrier recombination and more exposed active sites. Moreover, the excellent stability and reliability of the Ag/CuO/TiO{sub 2} photocatalyst demonstrated a promising application for organic pollutant removal from water.

  8. Nanotubes and nanowires

    Indian Academy of Sciences (India)

    Unknown

    junction nanotubes by the pyrolysis of appropriate organic precursors. ... By making use of carbon nanotubes, nanowires of metals, metal ..... The use of activated carbon in place of ..... required for the complete removal of the carbon template.

  9. Carbon nanotube nanoelectrode arrays

    Science.gov (United States)

    Ren, Zhifeng; Lin, Yuehe; Yantasee, Wassana; Liu, Guodong; Lu, Fang; Tu, Yi

    2008-11-18

    The present invention relates to microelectode arrays (MEAs), and more particularly to carbon nanotube nanoelectrode arrays (CNT-NEAs) for chemical and biological sensing, and methods of use. A nanoelectrode array includes a carbon nanotube material comprising an array of substantially linear carbon nanotubes each having a proximal end and a distal end, the proximal end of the carbon nanotubes are attached to a catalyst substrate material so as to form the array with a pre-determined site density, wherein the carbon nanotubes are aligned with respect to one another within the array; an electrically insulating layer on the surface of the carbon nanotube material, whereby the distal end of the carbon nanotubes extend beyond the electrically insulating layer; a second adhesive electrically insulating layer on the surface of the electrically insulating layer, whereby the distal end of the carbon nanotubes extend beyond the second adhesive electrically insulating layer; and a metal wire attached to the catalyst substrate material.

  10. Hydroxyapatite electrodeposition on anodized titanium nanotubes for orthopedic applications

    Energy Technology Data Exchange (ETDEWEB)

    Parcharoen, Yardnapar [Department of Biological Engineering, Faculty of Engineering, King Mongkut' s University of Technology Thonburi, Bangkok (Thailand); Kajitvichyanukul, Puangrat [Center of Excellence on Environmental Research and Innovation, Faculty of Engineering, Naresuan University, Phitsanulok (Thailand); Sirivisoot, Sirinrath [Department of Biological Engineering, Faculty of Engineering, King Mongkut' s University of Technology Thonburi, Bangkok (Thailand); Termsuksawad, Preecha, E-mail: preecha.ter@kmutt.ac.th [Division of Materials Technology, School of Energy, Environment and Materials, King Mongkut' s University of Technology Thonburi, 126 Pracha Uthit Rd., Bang Mod, ThungKhru, Bangkok 10140 (Thailand)

    2014-08-30

    Highlights: • We found that different anodization time of titanium significantly effects on nanotube length which further impacts adhesion strength of hydroxyapatite coating layers. • Adhesion strength of Hydroxyapatite (HA) coated on titanium dioxide nanotubes is better than that of HA coated on titanium plate. • Hydroxyapatite coated on titanium dioxide nanotubes showed higher cell density and better spreading of MC3T3-E1 cells (bone-forming cells) than that coated on titanium plate surface. - Abstract: Nanotubes modification for orthopedic implants has shown interesting biological performances (such as improving cell adhesion, cell differentiation, and enhancing osseointegration). The purpose of this study is to investigate effect of titanium dioxide (TiO{sub 2}) nanotube feature on performance of hydroxyapatite-coated titanium (Ti) bone implants. TiO{sub 2} nanotubes were prepared by anodization using ammonium fluoride electrolyte (NH{sub 4}F) with and without modifiers (PEG400 and Glycerol) at various potential forms, and times. After anodization, the nanotubes were subsequently annealed. TiO{sub 2} nanotubes were characterized by scanning electron microscope and X-ray diffractometer. The amorphous to anatase transformation due to annealing was observed. Smooth and highly organized TiO{sub 2} nanotubes were found when high viscous electrolyte, NH{sub 4}F in glycerol, was used. Negative voltage (−4 V) during anodization was confirmed to increase nanotube thickness. Length of the TiO{sub 2} nanotubes was significantly increased by times. The TiO{sub 2} nanotube was electrodeposited with hydroxyapatite (HA) and its adhesion was estimated by adhesive tape test. The result showed that nanotubes with the tube length of 560 nm showed excellent adhesion. The coated HA were tested for biological test by live/dead cell straining. HA coated on TiO{sub 2} nanotubes showed higher cells density, higher live cells, and more spreading of MC3T3-E1 cells than that

  11. SnS2 nanoflakes decorated multiwalled carbon nanotubes as high performance anode materials for lithium-ion batteries

    International Nuclear Information System (INIS)

    Sun, Hongyu; Ahmad, Mashkoor; Luo, Jun; Shi, Yingying; Shen, Wanci; Zhu, Jing

    2014-01-01

    Graphical abstract: The synthesized SnS 2 nanoflakes decorated multiwalled carbon nanotubes hybrid structures exhibit large reversible capacity, superior cycling performance, and good rate capability as compared to pure SnS 2 nanoflakes. - Highlights: • Synthesis of SnS 2 nanoflakes decorated multiwalled carbon nanotubes hybrid structures. • Simple solution-phase approach. • Morphology feature of SnS 2 . • Enhanced performance as Li-ion batteries. - Abstract: SnS 2 nanoflakes decorated multiwalled carbon nanotubes (MWCNTs) hybrid structures are directly synthesized via a simple solution-phase approach. The as-prepared SnS 2 /MWCNTs structures are investigated as anode materials for Li-ion batteries as compared with SnS 2 nanoflakes. It has been found that the composite structure exhibit excellent lithium storage performance with a large reversible capacity, superior cycling performance, and good rate capability as compared to pure SnS 2 nanoflakes. The first discharge and charge capacities have been found to be 1416 and 518 mA h g −1 for SnS 2 /MWCNTs composite electrodes at a current density of 100 mA g −1 between 5 mV and 1.15 V versus Li/Li + . A stable reversible capacity of ∼510 mA h g −1 is obtained for 50 cycles. The improved electrochemical performance may be attributed to the flake-morphology feature of SnS 2 and the addition of MWCNTs that can hinder the agglomeration of the active materials and improve the conductivity of the composite electrode simultaneously

  12. SnS{sub 2} nanoflakes decorated multiwalled carbon nanotubes as high performance anode materials for lithium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Hongyu [Beijing National Center for Electron Microscopy, The State Key Laboratory of New Ceramics and Fine Processing, Department of Material Science and Engineering, Tsinghua University, Beijing 100084 (China); Ahmad, Mashkoor, E-mail: mashkoorahmad2003@yahoo.com [Nanomaterials Research Group (NRG), Physics Division, PINSTECH, P.O. Nilore, Islamabad (Pakistan); Luo, Jun [Beijing National Center for Electron Microscopy, The State Key Laboratory of New Ceramics and Fine Processing, Department of Material Science and Engineering, Tsinghua University, Beijing 100084 (China); Shi, Yingying; Shen, Wanci [Laboratory of Advanced Materials, Department of Material Science and Engineering, Tsinghua University, Beijing 100084 (China); Zhu, Jing, E-mail: jzhu@mail.tsinghua.edu.cn [Beijing National Center for Electron Microscopy, The State Key Laboratory of New Ceramics and Fine Processing, Department of Material Science and Engineering, Tsinghua University, Beijing 100084 (China)

    2014-01-01

    Graphical abstract: The synthesized SnS{sub 2} nanoflakes decorated multiwalled carbon nanotubes hybrid structures exhibit large reversible capacity, superior cycling performance, and good rate capability as compared to pure SnS{sub 2} nanoflakes. - Highlights: • Synthesis of SnS{sub 2} nanoflakes decorated multiwalled carbon nanotubes hybrid structures. • Simple solution-phase approach. • Morphology feature of SnS{sub 2}. • Enhanced performance as Li-ion batteries. - Abstract: SnS{sub 2} nanoflakes decorated multiwalled carbon nanotubes (MWCNTs) hybrid structures are directly synthesized via a simple solution-phase approach. The as-prepared SnS{sub 2}/MWCNTs structures are investigated as anode materials for Li-ion batteries as compared with SnS{sub 2} nanoflakes. It has been found that the composite structure exhibit excellent lithium storage performance with a large reversible capacity, superior cycling performance, and good rate capability as compared to pure SnS{sub 2} nanoflakes. The first discharge and charge capacities have been found to be 1416 and 518 mA h g{sup −1} for SnS{sub 2}/MWCNTs composite electrodes at a current density of 100 mA g{sup −1} between 5 mV and 1.15 V versus Li/Li{sup +}. A stable reversible capacity of ∼510 mA h g{sup −1} is obtained for 50 cycles. The improved electrochemical performance may be attributed to the flake-morphology feature of SnS{sub 2} and the addition of MWCNTs that can hinder the agglomeration of the active materials and improve the conductivity of the composite electrode simultaneously.

  13. Ag2S/CdS/TiO2 Nanotube Array Films with High Photocurrent Density by Spotting Sample Method.

    Science.gov (United States)

    Sun, Hong; Zhao, Peini; Zhang, Fanjun; Liu, Yuliang; Hao, Jingcheng

    2015-12-01

    Ag2S/CdS/TiO2 hybrid nanotube array films (Ag2S/CdS/TNTs) were prepared by selectively depositing a narrow-gap semiconductor-Ag2S (0.9 eV) quantum dots (QDs)-in the local domain of the CdS/TiO2 nanotube array films by spotting sample method (SSM). The improvement of sunlight absorption ability and photocurrent density of titanium dioxide (TiO2) nanotube array films (TNTs) which were obtained by anodic oxidation method was realized because of modifying semiconductor QDs. The CdS/TNTs, Ag2S/TNTs, and Ag2S/CdS/TNTs fabricated by uniformly depositing the QDs into the TNTs via the successive ionic layer adsorption and reaction (SILAR) method were synthesized, respectively. The X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectrum (XPS) results demonstrated that the Ag2S/CdS/TNTs prepared by SSM and other films were successfully prepared. In comparison with the four films of TNTs, CdS/TNTs, Ag2S/TNTs, and Ag2S/CdS/TNTs by SILAR, the Ag2S/CdS/TNTs prepared by SSM showed much better absorption capability and the highest photocurrent density in UV-vis range (320~800 nm). The cycles of local deposition have great influence on their photoelectric properties. The photocurrent density of Ag2S/CdS/TNTs by SSM with optimum deposition cycles of 6 was about 37 times that of TNTs without modification, demonstrating their great prospective applications in solar energy utilization fields.

  14. A highly sensitive BTX sensor based on electrochemically derived wall connected TiO{sub 2} nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Dutta, K. [Nano-Thin Films and Solid State Gas Sensor Devices Laboratory, Department of Electronics and Telecommunication Engineering, Indian Institute of Engineering Science and Technology, Shibpur, Howrah 711103 (India); Chattopadhyay, P.P. [Department of Metallurgy and Materials Engineering, Indian Institute of Engineering Science and Technology, Shibpur, Howrah 711103 (India); Lu, Chia-Wei [Graduate Institute of Photonics and Optoelectronics, National Taiwan University, Taipei 10617, Taiwan (China); Ho, Mon-Shu [Department of Physics, National Chung Hsing University, Taichung 40227, Taiwan (China); Bhattacharyya, P., E-mail: pb_etc_besu@yahoo.com [Nano-Thin Films and Solid State Gas Sensor Devices Laboratory, Department of Electronics and Telecommunication Engineering, Indian Institute of Engineering Science and Technology, Shibpur, Howrah 711103 (India)

    2015-11-01

    Highlights: • Electrochemically synthesized TiO{sub 2} nanotube array for sensing benzene, toluene, and xylene (BTX) with enhanced sensitivity at relatively low temperature is reported. • Structural characterizations (XRD, FESEM, and AFM), have revealed that variation of the H{sub 2}O concentrations in mixed electrolyte comprising ethylene glycol and ammonium fluoride (NH{sub 4}F + EG) resulted in the formation of four distinct TiO{sub 2} nanoforms. • Photo luminescence spectra (PL spectra) analysis has revealed distinctly different stoichiometry of the four anodized sample. • Among the various nanoforms, the wall connected TiO{sub 2} nanotube array has been found to be the most efficient one for BTX sensing in the concentration range 20–400 ppm at relatively lower operating temperature (50–200 °C). • Among the three target species, benzene was found to offer the highest response magnitude followed by toluene and xylene at all the concentrations. - Abstract: This paper concerns development of electrochemically synthesized titanium dioxide (TiO{sub 2}) nanotube array for sensing the carcinogenic aromatic hydrocarbons like benzene, toluene, and xylene (BTX) with enhanced sensitivity achievable at relatively low temperature. Structural characterizations (XRD, FESEM), revealed that variation of the H{sub 2}O concentrations (1%, 2%, 5%, 8%, 10%, and 100% by volume) in mixed electrolyte, comprising of ethylene glycol (EG) and ammonium fluoride (NH{sub 4}F), resulted in the formation of six distinctly different TiO{sub 2} nanoforms. Photo luminescence spectra (PL spectra) analysis authenticated different stoichiometry of these six samples. Besides, the X-ray photoelectron spectroscopy (XPS) was carried out to investigate the defect states. The XPS study enables to correlate the oxygen vacancy concentration with the anodization parameters. Among the various nanoforms, the wall connected TiO{sub 2} nanotube array was found to be the most efficient one for BTX

  15. Stretchable Fiber Supercapacitors with High Volumetric Performance Based on Buckled MnO2 /Oxidized Carbon Nanotube Fiber Electrodes.

    Science.gov (United States)

    Li, Mingyang; Zu, Mei; Yu, Jinshan; Cheng, Haifeng; Li, Qingwen

    2017-03-01

    A stretchable fiber supercapacitor (SC) based on buckled MnO 2 /oxidized carbon nanotube (CNT) fiber electrode is fabricated by a simple prestraining-then-buckling method. The prepared stretchable fiber SC has a specific volumetric capacitance up to 409.4 F cm -3 , which is 33 times that of the pristine CNT fiber based SC, and shows the outstanding stability and repeatability in performance as a stretchable SC. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Thermophoresis of water droplets inside carbon nanotubes

    DEFF Research Database (Denmark)

    Zambrano, Harvey; Walther, Jens Honore; Oyarzua, Elton

    2016-01-01

    Carbon Nanotubes(CNTs) offer unique possibilities as fluid conduits with applications ranging from lab on a chip devices to encapsulation media for drug delivery. CNTs feature high mechanical strength, chemical and thermalstability and biocompatibility therefore they are promising candidates...

  17. The study of explosive emission from carbon nanotubes

    International Nuclear Information System (INIS)

    Korenev, Sergey

    2002-01-01

    The carbon nanotubes (CNT) found applications for high density current electron emitters. The main interest for forming of high current electron beams using CNT is high concentration of electrical field on the nanotubes and high value of yield by electrons for field emission. The experimental results for time processes of forming cathode plasma and extraction of electron beam are presented in the report

  18. Silicon nanotube field effect transistor with core-shell gate stacks for enhanced high-performance operation and area scaling benefits

    KAUST Repository

    Fahad, Hossain M.

    2011-10-12

    We introduce the concept of a silicon nanotube field effect transistor whose unique core-shell gate stacks help achieve full volume inversion by giving a surge in minority carrier concentration in the near vicinity of the ultrathin channel and at the same time rapid roll-off at the source and drain junctions constituting velocity saturation-induced higher drive current-enhanced high performance per device with efficient real estate consumption. The core-shell gate stacks also provide superior short channel effects control than classical planar metal oxide semiconductor field effect transistor (MOSFET) and gate-all-around nanowire FET. The proposed device offers the true potential to be an ideal blend for quantum ballistic transport study of device property control by bottom-up approach and high-density integration compatibility using top-down state-of-the-art complementary metal oxide semiconductor flow. © 2011 American Chemical Society.

  19. Silicon nanotube field effect transistor with core-shell gate stacks for enhanced high-performance operation and area scaling benefits

    KAUST Repository

    Fahad, Hossain M.; Smith, Casey; Rojas, Jhonathan Prieto; Hussain, Muhammad Mustafa

    2011-01-01

    We introduce the concept of a silicon nanotube field effect transistor whose unique core-shell gate stacks help achieve full volume inversion by giving a surge in minority carrier concentration in the near vicinity of the ultrathin channel and at the same time rapid roll-off at the source and drain junctions constituting velocity saturation-induced higher drive current-enhanced high performance per device with efficient real estate consumption. The core-shell gate stacks also provide superior short channel effects control than classical planar metal oxide semiconductor field effect transistor (MOSFET) and gate-all-around nanowire FET. The proposed device offers the true potential to be an ideal blend for quantum ballistic transport study of device property control by bottom-up approach and high-density integration compatibility using top-down state-of-the-art complementary metal oxide semiconductor flow. © 2011 American Chemical Society.

  20. Possible High Thermoelectric Power in Semiconducting Carbon Nanotubes ˜A Case Study of Doped One-Dimensional Semiconductors˜

    Science.gov (United States)

    Yamamoto, Takahiro; Fukuyama, Hidetoshi

    2018-02-01

    We have theoretically investigated the thermoelectric properties of impurity-doped one-dimensional semiconductors, focusing on nitrogen-substituted (N-substituted) carbon nanotubes (CNTs), using the Kubo formula combined with a self-consistent t-matrix approximation. N-substituted CNTs exhibit extremely high thermoelectric power factor (PF) values originating from a characteristic of one-dimensional materials where decrease in the carrier density increase both the electrical conductivity and the Seebeck coefficient in the low-N regime. The chemical potential dependence of the PF values of semiconducting CNTs has also been studied as a field-effect transistor and it turns out that the PF values show a noticeable maximum in the vicinity of the band edges. This result demonstrates that "band-edge engineering" will be crucial for solid development of high-performance thermoelectric materials.

  1. Carbon nanotube-supported Au-Pd alloy with cooperative effect of metal nanoparticles and organic ketone/quinone groups as a highly efficient catalyst for aerobic oxidation of amines.

    Science.gov (United States)

    Deng, Weiping; Chen, Jiashu; Kang, Jincan; Zhang, Qinghong; Wang, Ye

    2016-05-21

    Functionalised carbon nanotube (CNT)-supported Au-Pd alloy nanoparticles were highly efficient catalysts for the aerobic oxidation of amines. We achieved the highest turnover frequencies (>1000 h(-1)) for the oxidative homocoupling of benzylamine and the oxidative dehydrogenation of dibenzylamine. We discovered a cooperative effect between Au-Pd nanoparticles and ketone/quinone groups on CNTs.

  2. Scalable Fabrication of High-Performance Transparent Conductors Using Graphene Oxide-Stabilized Single-Walled Carbon Nanotube Inks

    Directory of Open Access Journals (Sweden)

    Linxiang He

    2018-04-01

    Full Text Available Recent development in liquid-phase processing of single-walled carbon nanotubes (SWNTs has revealed rod-coating as a promising approach for large-scale production of SWNT-based transparent conductors. Of great importance in the ink formulation is the stabilizer having excellent dispersion stability, environmental friendly and tunable rheology in the liquid state, and also can be readily removed to enhance electrical conductivity and mechanical stability. Herein we demonstrate the promise of graphene oxide (GO as a synergistic stabilizer for SWNTs in water. SWNTs dispersed in GO is formulated into inks with homogeneous nanotube distribution, good wetting and rheological properties, and compatible with industrial rod coating practice. Microwave treatment of rod-coated films can reduce GOs and enhance electro-optical performance. The resultant films offer a sheet resistance of ~80 Ω/sq at 86% transparency, along with good mechanical flexibility. Doping the films with nitric acid can further decrease the sheet resistance to ~25 Ω/sq. Comparing with the films fabricated from typical surfactant-based SWNT inks, our films offer superior adhesion as assessed by the Scotch tape test. This study provides new insight into the selection of suitable stabilizers for functional SWNT inks with strong potential for printed electronics.

  3. Non-carbon titanium cobalt nitride nanotubes supported platinum catalyst with high activity and durability for methanol oxidation reaction

    Science.gov (United States)

    Chen, Xiaoxiang; Li, Wuyi; Pan, Zhanchang; Xu, Yanbin; Liu, Gen; Hu, Guanghui; Wu, Shoukun; Li, Jinghong; Chen, Chun; Lin, Yingsheng

    2018-05-01

    Titanium cobalt nitride nanotubes (Ti0.95Co0.05N NTs) hybrid support, a novel robust non-carbon support material prepared by solvothermal and post-nitriding processes, is further decorated with Pt nanoparticles for the electrooxidation of methanol. The catalyst is characterized by X-ray diffraction (XRD), nitrogen adsorption/desorption, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and electrochemical measurements. The morphology, structure and composition of the synthesized Ti0.95Co0.05N NTs suggest that the nanotube wall is porous and consists of homogeneous cohesively attached nitrides nanocube particles. Notable, Ti0.95Co0.05N NTs supported Pt catalyst exhibits significantly improved catalytic activity and durability for methanol electrooxidation compared with the conventional JM Pt/C catalyst. The experimental data indicate that enhanced catalytic activity and stability of Pt/Ti0.95Co0.05N NTs towards methanol electrooxidation might be mainly attributed to the tubular nanostructures and synergistic effect introduced by the Co doping. Both of them are playing an important role in improving the activity and durability of the Ti0.95Co0.05N NTs catalyst.

  4. Preparation of N-doped ZnO-loaded halloysite nanotubes catalysts with high solar-light photocatalytic activity.

    Science.gov (United States)

    Cheng, Zhi-Lin; Sun, Wei

    2015-01-01

    N-doped ZnO nanoparticles were successfully assembled into hollow halloysite nanotubes (HNTs) by using the impregnation method. The catalysts based on N-doped ZnO-loaded HNTs nanocomposites (N-doped ZnO/HNTs) were characterized by X-ray diffraction (XRD), transmission electron microscopy-energy dispersive X-ray (TEM-EDX), scanning electron microscopy-energy dispersive X-ray (SEM-EDX), UV-vis and Fourier transform infrared spectroscopy (FT-IR) techniques. The XRD pattern showed ZnO nanoparticles with hexagonal structure loaded on HNTs. The TEM-EDX analysis indicated ZnO particles with the crystal size of ca.10 nm scattered in hollow structure of HNTs, and furthermore the concentration of N atom in nanocomposites was up to 2.31%. The SEM-EDX verified most of N-ZnO nanoparticles existing in hollow nanotubes of HNTs. Besides containing an obvious ultraviolet absorbance band, the UV-vis spectra of the N-doped ZnO/HNTs catalysts showed an available visible absorbance band by comparing to HNTs and non-doped ZnO/HNTs. The photocatalytic activity of the N-doped ZnO/HNTs catalysts was evaluated by the degradation of methyl orange (MO) solution with the concentration of 20 mg/L under the simulated solar-light irradiation. The result showed that the N-doped ZnO/HNTs catalyst exhibited a desirable solar-light photocatalytic activity.

  5. A compact multi-wavelength optoacoustic system based on high-power diode lasers for characterization of double-walled carbon nanotubes (DWCNTs) for biomedical applications

    Science.gov (United States)

    Leggio, Luca; de Varona, Omar; Escudero, Pedro; Carpintero del Barrio, Guillermo; Osiński, Marek; Lamela Rivera, Horacio

    2015-06-01

    During the last decade, Optoacoustic Imaging (OAI), or Optoacoustic Tomography (OAT), has evolved as a novel imaging technique based on the generation of ultrasound waves with laser light. OAI may become a valid alternative to techniques currently used for the detection of diseases at their early stages. It has been shown that OAI combines the high contrast of optical imaging techniques with high spatial resolution of ultrasound systems in deep tissues. In this way, the use of nontoxic biodegradable contrast agents that mark the presence of diseases in near-infrared (NIR) wavelengths range (0.75-1.4 um) has been considered. The presence of carcinomas and harmful microorganisms can be revealed by means of the fluorescence effect exhibited by biopolymer nanoparticles. A different approach is to use carbon nanotubes (CNTs) which are a contrast agent in NIR range due to their absorption characteristics in the range between 800 to 1200 nm. We report a multi-wavelength (870 and 905 nm) laser diode-based optoacoustic (OA) system generating ultrasound signals from a double-walled carbon nanotubes (DWCNTs) solution arranged inside a tissue-like phantom, mimicking the scattering of a biological soft tissue. Optoacoustic signals obtained with DWCNTs inclusions within a tissue-like phantom are compared with the case of ink-filled inclusions, with the aim to assess their absorption. These measurements are done at both 870 and 905 nm, by using high power laser diodes as light sources. The results show that the absorption is relatively high when the inclusion is filled with ink and appreciable with DWCNTs.

  6. Ballistic resistance capacity of carbon nanotubes

    International Nuclear Information System (INIS)

    Mylvaganam, Kausala; Zhang, L C

    2007-01-01

    Carbon nanotubes have high strength, light weight and excellent energy absorption capacity and therefore have great potential applications in making antiballistic materials. By examining the ballistic impact and bouncing-back processes on carbon nanotubes, this investigation shows that nanotubes with large radii withstand higher bullet speeds and the ballistic resistance is the highest when the bullet hits the centre of the CNT; the ballistic resistance of CNTs will remain the same on subsequent bullet strikes if the impact is after a small time interval

  7. Methods for producing reinforced carbon nanotubes

    Science.gov (United States)

    Ren, Zhifen [Newton, MA; Wen, Jian Guo [Newton, MA; Lao, Jing Y [Chestnut Hill, MA; Li, Wenzhi [Brookline, MA

    2008-10-28

    Methods for producing reinforced carbon nanotubes having a plurality of microparticulate carbide or oxide materials formed substantially on the surface of such reinforced carbon nanotubes composite materials are disclosed. In particular, the present invention provides reinforced carbon nanotubes (CNTs) having a plurality of boron carbide nanolumps formed substantially on a surface of the reinforced CNTs that provide a reinforcing effect on CNTs, enabling their use as effective reinforcing fillers for matrix materials to give high-strength composites. The present invention also provides methods for producing such carbide reinforced CNTs.

  8. Carbon Nanotubes as Optical Sensors in Biomedicine.

    Science.gov (United States)

    Farrera, Consol; Torres Andón, Fernando; Feliu, Neus

    2017-11-28

    Single-walled carbon nanotubes (SWCNTs) have become potential candidates for a wide range of medical applications including sensing, imaging, and drug delivery. Their photophysical properties (i.e., the capacity to emit in the near-infrared), excellent photostability, and fluorescence, which is highly sensitive to the local environment, make SWCNTs promising optical probes in biomedicine. In this Perspective, we discuss the existing strategies for and challenges of using carbon nanotubes for medical diagnosis based on intracellular sensing as well as discuss also their biocompatibility and degradability. Finally, we highlight the potential improvements of this nanotechnology and future directions in the field of carbon nanotubes for biomedical applications.

  9. Carbon nanotube: the inside story.

    Science.gov (United States)

    Ando, Yoshinori

    2010-06-01

    Carbon nanotubes (CNTs) were serendipitously discovered as a byproduct of fullerenes by direct current (DC) arc discharge; and today this is the most-wanted material in the nanotechnology research. In this brief review, I begin with the history of the discovery of CNTs and focus on CNTs produced by arc discharge in hydrogen atmosphere, which is little explored outside my laboratory. DC arc discharge evaporation of pure graphite rod in pure hydrogen gas results in multi-walled carbon nanotubes (MWCNTs) of high crystallinity in the cathode deposit. As-grown MWCNTs have very narrow inner diameter. Raman spectra of these MWCNTs show high-intensity G-band, unusual high-frequency radial breathing mode at 570 cm(-1), and a new characteristic peak near 1850 cm(-1). Exciting carbon nanowires (CNWs), consisting of a linear carbon chain in the center of MWCNTs are also produced. Arc evaporation of graphite rod containing metal catalysts results in single-wall carbon nanotubes (SWCNTs) in the whole chamber like macroscopic webs. Two kinds of arc method have been developed to produce SWCNTs: Arc plasma jet (APJ) and Ferrum-Hydrogen (FH) arc methods. Some new purification methods for as-produced SWCNTs are reviewed. Finally, double-walled carbon nanotubes (DWCNTs) are also described.

  10. Soluble organic nanotubes for catalytic systems

    Science.gov (United States)

    Xiong, Linfeng; Yang, Kunran; Zhang, Hui; Liao, Xiaojuan; Huang, Kun

    2016-03-01

    In this paper, we report a novel method for constructing a soluble organic nanotube supported catalyst system based on single-molecule templating of core-shell bottlebrush copolymers. Various organic or metal catalysts, such as sodium prop-2-yne-1-sulfonate (SPS), 1-(2-(prop-2-yn-1-yloxy)ethyl)-1H-imidazole (PEI) and Pd(OAc)2 were anchored onto the tube walls to functionalize the organic nanotubes via copper-catalyzed azide-alkyne cycloaddition (CuAAC) reaction. Depending on the ‘confined effect’ and the accessible cavity microenvironments of tubular structures, the organic nanotube catalysts showed high catalytic efficiency and site-isolation features. We believe that the soluble organic nanotubes will be very useful for the development of high performance catalyst systems due to their high stability of support, facile functionalization and attractive textural properties.

  11. Soluble organic nanotubes for catalytic systems.

    Science.gov (United States)

    Xiong, Linfeng; Yang, Kunran; Zhang, Hui; Liao, Xiaojuan; Huang, Kun

    2016-03-18

    In this paper, we report a novel method for constructing a soluble organic nanotube supported catalyst system based on single-molecule templating of core–shell bottlebrush copolymers. Various organic or metal catalysts, such as sodium prop-2-yne-1-sulfonate (SPS), 1-(2-(prop-2-yn-1-yloxy)ethyl)-1H-imidazole (PEI) and Pd(OAc)2 were anchored onto the tube walls to functionalize the organic nanotubes via copper-catalyzed azide-alkyne cycloaddition (CuAAC) reaction. Depending on the 'confined effect' and the accessible cavity microenvironments of tubular structures, the organic nanotube catalysts showed high catalytic efficiency and site-isolation features. We believe that the soluble organic nanotubes will be very useful for the development of high performance catalyst systems due to their high stability of support, facile functionalization and attractive textural properties.

  12. Vertically aligned multiwalled carbon nanotubes as electronic interconnects

    Science.gov (United States)

    Gopee, Vimal Chandra

    The drive for miniaturisation of electronic circuits provides new materials challenges for the electronics industry. Indeed, the continued downscaling of transistor dimensions, described by Moore’s Law, has led to a race to find suitable replacements for current interconnect materials to replace copper. Carbon nanotubes have been studied as a suitable replacement for copper due to its superior electrical, thermal and mechanical properties. One of the advantages of using carbon nanotubes is their high current carrying capacity which has been demonstrated to be three orders of magnitude greater than that of copper. Most approaches in the implementation of carbon nanotubes have so far focused on the growth in vias which limits their application. In this work, a process is described for the transfer of carbon nanotubes to substrates allowing their use for more varied applications. Arrays of vertically aligned multiwalled carbon nanotubes were synthesised by photo-thermal chemical vapour deposition with high growth rates. Raman spectroscopy was used to show that the synthesised carbon nanotubes were of high quality. The carbon nanotubes were exposed to an oxygen plasma and the nature of the functional groups present was determined using X-ray photoelectron spectroscopy. Functional groups, such as carboxyl, carbonyl and hydroxyl groups, were found to be present on the surface of the multiwalled carbon nanotubes after the functionalisation process. The multiwalled carbon nanotubes were metallised after the functionalisation process using magnetron sputtering. Two materials, solder and sintered silver, were chosen to bind carbon nanotubes to substrates so as to enable their transfer and also to make electrical contact. The wettability of solder to carbon nanotubes was investigated and it was demonstrated that both functionalisation and metallisation were required in order for solder to bond with the carbon nanotubes. Similarly, functionalisation followed by metallisation

  13. Review on properties, dispersion and toxicology of carbon nanotubes

    International Nuclear Information System (INIS)

    Saeed, K.

    2010-01-01

    Carbon nanotubes (CNTs) have the most intensely studied nano structures because of their unique properties. There are two types of carbon nanotubes CNTs, single-walled carbon nanotubes (SWNTs) and multi-walled carbon nanotubes (MWNTs), prepared by chemical-vapour deposition (CVD), plasma enhanced chemical-vapour deposition, thermal chemical vapour deposition, Vapour phase growth, Arc discharge and Lasser ablation. Both single-walled carbon nanotubes (SWNTs) and multi-walled carbon nanotubes (MWNTs) possess high mechanical and electrical conductivity, ultra-light weight, high aspect ratio and have excellent chemical and thermal stabilities. They also possess semi- and metallic-conductive properties depending upon their chirality. This review focuses on progress toward functionalization (not only dispersed nano tube but also dramatically improve their solubility), preparation and purification, composites and the toxicity of the carbon nanotubes (CNTs). The functional groups attached to carbon nanotubes (CNTs) should react with polymers a