WorldWideScience

Sample records for nanotubes synthesis optical

  1. Synthesis and optical characterization of carbon nanotube arrays

    Energy Technology Data Exchange (ETDEWEB)

    Rahman, Md. Mahfuzur, E-mail: mrahman@masdar.ac.ae [Institute Centre for Energy (iEnergy), Mechanical and Materials Engineering Department, Masdar Institute of Science and Technology (MIST), P.O. Box 54224, Abu Dhabi (United Arab Emirates); Younes, Hammad [Institute Centre for Energy (iEnergy), Mechanical and Materials Engineering Department, Masdar Institute of Science and Technology (MIST), P.O. Box 54224, Abu Dhabi (United Arab Emirates); Ni, George [Department of Mechanical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge, MA 02139 (United States); Zhang, TieJun [Institute Centre for Energy (iEnergy), Mechanical and Materials Engineering Department, Masdar Institute of Science and Technology (MIST), P.O. Box 54224, Abu Dhabi (United Arab Emirates); Al Ghaferi, Amal, E-mail: aalghaferi@masdar.ac.ae [Institute Centre for Energy (iEnergy), Mechanical and Materials Engineering Department, Masdar Institute of Science and Technology (MIST), P.O. Box 54224, Abu Dhabi (United Arab Emirates)

    2016-05-15

    Highlights: • Controlling metallicity and vertical alignment of CNT forest by changing hydrogen catalyst annealing time and growth pressure. • Verifying metallicity using Raman spectroscopy of top CNT layer. • Optical characterization of CNT forest using UV–vis–NIR spectrophotometer. - Abstract: Catalyst annealing time and growth pressure play a crucial role in the chiral selective and high-efficiency growth of single-walled carbon nanotubes (SWCNTs) during low pressure chemical vapor deposition (LPCVD). We achieved a high growth rates for SWCNTs and a change the chiral distribution towards metallic (n, m) increasing the catalyst annealing time in hydrogen. A strong correlation is revealed between the catalyst annealing time at lower growth pressures and the shape of the G band, which indicates the metallic or semiconducting nature of the SWCNT and predict the chirality distribution. Under a 15 min annealing time and 10 mbar of growth pressure, the bottom of the G band is broadened with a sharp G{sup −} peak, and the G-band exhibited asymmetrical Breit–Wigner–Fano (BWF) shape. In addition, the growth of SWCNTs with smaller diameters and rich in metallic character is confirmed by the shift of the G-band to a smaller Raman frequency. Homogeneity and vertical alignment of as-grown SWCNT arrays are optically studied using UV/vis/NIR Spectrophotometer. Wavelength-independent and low reflectance resulted from the growth of uniform arrays of SWCNTs. Because of their tunable electronic and optical properties, selective growth of SWCNTs promises great application potential, particularly in electronics and solar industries.

  2. Synthesis and properties of Co-doped titanate nanotubes and their optical sensitization with methylene blue

    International Nuclear Information System (INIS)

    Ferreira, V.C.; Nunes, M.R.; Silvestre, A.J.; Monteiro, O.C.

    2013-01-01

    Here we report on a novel chemical route to synthesize homogenous cobalt-doped titanate nanotubes (CoTNT), using an amorphous Co-doped precursor. The influence of the synthesis temperature, autoclave dwell time and metal doping on the structural and microstructural as well as on the optical properties of the synthesized titanate nanotubes is studied and discussed. The optical band gaps of the CoTNT samples are red shifted in comparison with the values determined for the undoped samples, such red shifts bringing the absorption edge of the CoTNT samples into the visible region. CoTNT materials also demonstrate particular high adsorption ability for methylene blue, the amount of the adsorbed dye being higher than the one predictable for a monolayer formation. This suggests the possibility of intercalation of the dye molecule between the TiO 6 layers of the TNT structure. It is also shown that the methylene blue sensitized Co-doped nanostructures are highly stable under UV radiation and present a strong and broad absorption in the visible region. - Highlights: • New hydrothermal chemical route to synthesize cobalt-doped titanate nanotubes. • The Co-doping stabilizes the TNTs morphology in a temperature range of 160–200 °C. • Optical band gaps of CoTNTs are red shifted compared to the TNT samples. • Methylene blue sensitized CoTNTs are highly stable under UV–vis irradiation

  3. Synthesis and properties of Co-doped titanate nanotubes and their optical sensitization with methylene blue

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, V.C. [University of Lisbon, Faculty of Sciences, Department of Chemistry and Biochemistry and CQB, Campo Grande, 1749-016 Lisboa (Portugal); Nunes, M.R. [University of Lisbon, Faculty of Sciences, Department of Chemistry and Biochemistry and CCMM, Campo Grande, 1749-016 Lisboa (Portugal); Silvestre, A.J. [Instituto Superior de Engenharia de Lisboa, Department of Physics and ICEMS, R. Conselheiro Emídio Navarro 1, 1959-007 Lisboa (Portugal); Monteiro, O.C., E-mail: ocmonteiro@fc.ul.pt [University of Lisbon, Faculty of Sciences, Department of Chemistry and Biochemistry and CQB, Campo Grande, 1749-016 Lisboa (Portugal)

    2013-10-01

    Here we report on a novel chemical route to synthesize homogenous cobalt-doped titanate nanotubes (CoTNT), using an amorphous Co-doped precursor. The influence of the synthesis temperature, autoclave dwell time and metal doping on the structural and microstructural as well as on the optical properties of the synthesized titanate nanotubes is studied and discussed. The optical band gaps of the CoTNT samples are red shifted in comparison with the values determined for the undoped samples, such red shifts bringing the absorption edge of the CoTNT samples into the visible region. CoTNT materials also demonstrate particular high adsorption ability for methylene blue, the amount of the adsorbed dye being higher than the one predictable for a monolayer formation. This suggests the possibility of intercalation of the dye molecule between the TiO{sub 6} layers of the TNT structure. It is also shown that the methylene blue sensitized Co-doped nanostructures are highly stable under UV radiation and present a strong and broad absorption in the visible region. - Highlights: • New hydrothermal chemical route to synthesize cobalt-doped titanate nanotubes. • The Co-doping stabilizes the TNTs morphology in a temperature range of 160–200 °C. • Optical band gaps of CoTNTs are red shifted compared to the TNT samples. • Methylene blue sensitized CoTNTs are highly stable under UV–vis irradiation.

  4. Side-by-Side In(OH3 and In2O3 Nanotubes: Synthesis and Optical Properties

    Directory of Open Access Journals (Sweden)

    Tao Xiaojun

    2009-01-01

    Full Text Available Abstract A simple and mild wet-chemical approach was developed for the synthesis of one-dimensional (1D In(OH3 nanostructures. By calcining the 1D In(OH3 nanocrystals in air at 250 °C, 1D In2O3 nanocrystals with the same morphology were obtained. TEM results show that both 1D In(OH3 and 1D In2O3 are composed of uniform nanotube bundles. SAED and XRD patterns indicate that 1D In(OH3 and 1D In2O3 nanostructures are single crystalline and possess the same bcc crystalline structure as the bulk In(OH3 and In2O3, respectively. TGA/DTA analyses of the precursor In(OH3 and the final product In2O3 confirm the existence of CTAB molecules, and its content is about 6%. The optical absorption band edge of 1D In2O3 exhibits an evident blueshift with respect to that of the commercial In2O3 powders, which is caused by the increasing energy gap resulted from decreasing the grain size. A relatively strong and broad purple-blue emission band centered at 440 nm was observed in the room temperature PL spectrum of 1D In2O3 nanotube bundles, which was mainly attributed to the existence of the oxygen vacancies.

  5. Tunable synthesis of copper nanotubes

    International Nuclear Information System (INIS)

    Kaniukov, E; Yakimchuk, D; Kozlovsky, A; Shlimas, D; Zdorovets, M; Kadyrzhanov, K

    2016-01-01

    Simple method of tunable synthesis of copper nanotubes based on template synthesis was developed. A comprehensive study of the structural, morphological and electrical characteristics of the obtained nanostructures was carried out. Characterization of structural features was made by methods of scanning electron microscopy, energy dispersive spectroscopy and X-ray diffractometry analysis. Evaluation of wall thickness is made by methods of gas permeability. Electrical conductivity of nanotubes was define in the study of their current-voltage characteristics. The possibility to control of copper nanotubes physical properties by variation of the deposition parameters was shown. (paper)

  6. Conventional hydrothermal synthesis of titanate nanotubes: Systematic discussions on structural, optical, thermal and morphological properties

    Directory of Open Access Journals (Sweden)

    S. Muniyappan

    2017-12-01

    Full Text Available Titanate nanotubes were successfully synthesized by hydrothermal technique under acidic-base medium. The anatase and titanate phase of the starting TiO2 and tubular titanate was confirmed by powder XRD technique. The UV–vis-NIR spectroscopy was used to study the absorption nature of titanate nanotubes and the band gap was calculated as 3.3 eV. Infrared technique was employed to detect the presence of all the functional groups in the synthesized titanate nanotube material. Thermal properties of the title material were studied by TG-DTA analyses. The shrinkage of interlayer distance of TiO2 network confirms the nanotube formation. Morphology and size information about the synthesized material were carried out using FESEM and TEM analysis. Titanate nanotubes are having the maximum length of 2.24 µm and the average diameter of 169.73 nm. EDX analysis gives out the elemental composition of the as synthesized product. This report may fetch an efficient way to synthesize TiO2 nanotubes using TiO2 nanoparticles.

  7. Polymer nanotube nanocomposites: synthesis, properties, and applications

    National Research Council Canada - National Science Library

    Mittal, Vikas

    2010-01-01

    ... in these commercially important areas of polymer technology. It sums up recent advances in nanotube composite synthesis technology, provides basic introduction to polymer nanotubes nanocomposite technology for the readers new to this field, provides valuable...

  8. Synthesis of carbon nanotubes and nanotube forests on copper catalyst

    International Nuclear Information System (INIS)

    Kruszka, Bartosz; Terzyk, Artur P; Wiśniewski, Marek; Gauden, Piotr A; Szybowicz, Mirosław

    2014-01-01

    The growth of carbon nanotubes on bulk copper is studied. We show for the first time, that super growth chemical vapor deposition method can be successfully applied for preparation of nanotubes on copper catalyst, and the presence of hydrogen is necessary. Next, different methods of copper surface activation are studied, to improve catalyst efficiency. Among them, applied for the first time for copper catalyst in nanotubes synthesis, sulfuric acid activation is the most promising. Among tested samples the surface modified for 10 min is the most active, causing the growth of vertically aligned carbon nanotube forests. Obtained results have potential importance in application of nanotubes and copper in electronic chips and nanodevices. (paper)

  9. Optical properties of carbon nanotubes

    Science.gov (United States)

    Chen, Gugang

    This thesis addresses the optical properties of novel carbon filamentary nanomaterials: single-walled carbon nanotubes (SWNTs), double-walled carbon nanotubes (DWNTs), and SWNTs with interior C60 molecules ("peapods"). Optical reflectance spectra of bundled SWNTs are discussed in terms of their electronic energy band structure. An Effective Medium Model for a composite material was found to provide a reasonable description of the spectra. Furthermore, we have learned from optical absorption studies of DWNTs and C60-peapods that the host tube and the encapsulant interact weakly; small shifts in interband absorption structure were observed. Resonant Raman scattering studies on SWNTs synthesized via the HiPCO process show that the "zone-folding" approximation for phonons and electrons works reasonably well, even for small diameter (d effect, rather than the vdW interaction. Finally, we studied the chemical doping of DWNTs, where the dopant (Br anions) is chemically bound to the outside of the outer tube. The doped DWNT system is a model for a cylindrical molecular capacitor. We found experimentally that 90% of the positive charge resides on the outer tube, so that most of electric field on the inner tube is screened, i.e., we have observed a molecular Faraday cage effect. A self-consistent theoretical model in the tight-binding approximation with a classical electrostatic energy term is in good agreement with our experimental results.

  10. Facile Synthesis of Ternary Boron Carbonitride Nanotubes

    Directory of Open Access Journals (Sweden)

    Luo Lijie

    2009-01-01

    Full Text Available Abstract In this study, a novel and facile approach for the synthesis of ternary boron carbonitride (B–C–N nanotubes was reported. Growth occurred by heating simple starting materials of boron powder, zinc oxide powder, and ethanol absolute at 1150 °C under a mixture gas flow of nitrogen and hydrogen. As substrate, commercial stainless steel foil with a typical thickness of 0.05 mm played an additional role of catalyst during the growth of nanotubes. The nanotubes were characterized by SEM, TEM, EDX, and EELS. The results indicate that the synthesized B–C–N nanotubes exhibit a bamboo-like morphology and B, C, and N elements are homogeneously distributed in the nanotubes. A catalyzed vapor–liquid–solid (VLS mechanism was proposed for the growth of the nanotubes.

  11. Diameter grouping in bulk samples of single-walled carbon nanotubes from optical absorption spectroscopy

    NARCIS (Netherlands)

    Golden, M.S.; Fink, J.; Dunsch, L.; Bauer, H.-D.; Reibold, M.; Knupfer, M.; Friedlein, R.; Pichler, T.; Jost, O.

    1999-01-01

    The influence of the synthesis parameters on the mean characteristics of single-wall carbon nanotubes in soot produced by the laser vaporization of graphite has been analyzed using optical absorption spectroscopy. The abundance and mean diameter of the nanotubes were found to be most influenced by

  12. A carbon nanotube optical rectenna

    Science.gov (United States)

    Sharma, Asha; Singh, Virendra; Bougher, Thomas L.; Cola, Baratunde A.

    2015-12-01

    An optical rectenna—a device that directly converts free-propagating electromagnetic waves at optical frequencies to direct current—was first proposed over 40 years ago, yet this concept has not been demonstrated experimentally due to fabrication challenges at the nanoscale. Realizing an optical rectenna requires that an antenna be coupled to a diode that operates on the order of 1 PHz (switching speed on the order of 1 fs). Diodes operating at these frequencies are feasible if their capacitance is on the order of a few attofarads, but they remain extremely difficult to fabricate and to reliably couple to a nanoscale antenna. Here we demonstrate an optical rectenna by engineering metal-insulator-metal tunnel diodes, with a junction capacitance of ˜2 aF, at the tip of vertically aligned multiwalled carbon nanotubes (˜10 nm in diameter), which act as the antenna. Upon irradiation with visible and infrared light, we measure a d.c. open-circuit voltage and a short-circuit current that appear to be due to a rectification process (we account for a very small but quantifiable contribution from thermal effects). In contrast to recent reports of photodetection based on hot electron decay in a plasmonic nanoscale antenna, a coherent optical antenna field appears to be rectified directly in our devices, consistent with rectenna theory. Finally, power rectification is observed under simulated solar illumination, and there is no detectable change in diode performance after numerous current-voltage scans between 5 and 77 °C, indicating a potential for robust operation.

  13. Optical Characterization and Applications of Single Walled Carbon Nanotubes

    Science.gov (United States)

    Strano, Michael S.

    2005-03-01

    have a tunable n-IR emission that responds to changes in the local dielectric function but remains stable to permanent photobleaching. We report the synthesis and successful testing of solution phase, near-infrared sensors, with β-D-glucose sensing as a model system, using single walled carbon nanotubes that modulate their emission in response to the adsorption of specific biomolecules. New types of non-covalent functionalization using electron withdrawing molecules are shown to provide sites for transferring electrons in and out of the nanotube. We also show two distinct mechanisms of signal transduction -- fluorescence quenching and charge transfer. The results demonstrate new opportunities for nanoparticle optical sensors that operate in strongly absorbing media of relevance to medicine or biology.

  14. Optical properties of titanium dioxide nanotube arrays

    Energy Technology Data Exchange (ETDEWEB)

    Abdelmoula, Mohamed [Department of Physics, Northeastern University, Boston, Massachusetts 02115 (United States); Department of Materials Science, Carnegie Mellon University, Pittsburgh, PA 15213 (United States); Sokoloff, Jeffrey; Lu, Wen-Tao; Menon, Latika [Department of Physics, Northeastern University, Boston, Massachusetts 02115 (United States); Close, Thomas; Richter, Christiaan, E-mail: christiaan.richter@rit.edu [Department of Chemical Engineering, Rochester Institute of Technology, Rochester, New York, 14623 (United States)

    2014-01-07

    We present experimental measurements and a theoretical analysis of the near UV to NIR optical properties of free standing titania nanotube arrays. An improved understanding of the optical physics of this type of nanostructure is important to several next generation solar energy conversion technologies. We measured the transmission, reflection, and absorption of the electromagnetic spectrum from 300 nm to 1000 nm (UV to NIR) of titania nanotube arrays. We measured the total, specular, and diffuse reflection and transmission using both single point detection and an integrating sphere spectrometer. We find that the transmission, but not the reflection, of light (UV to NIR) through the nanotube array is well-explained by classic geometric optics using an effective medium model taking into account the conical geometry of the nanotubes. For wavelengths shorter than ∼500 nm, we find the surprising result that the reflection coefficient for light incident on the open side of the nanotube array is greater than the reflection coefficient for light incident on the closed “floor” of the nanotube array. We consider theoretical models based on the eikonal approximation, photonic crystal band theory, and a statistical treatment of scattering to explain the observed data. We attribute the fact that light with wavelengths shorter than 500 nm is more highly reflected from the open than the closed tube side as being due to disorder scattering inside the nanotube array.

  15. Optical trapping of carbon nanotubes and graphene

    Directory of Open Access Journals (Sweden)

    S. Vasi

    2011-09-01

    Full Text Available We study optical trapping of nanotubes and graphene. We extract the distribution of both centre-of-mass and angular fluctuations from three-dimensional tracking of these optically trapped carbon nanostructures. The optical force and torque constants are measured from auto and cross-correlation of the tracking signals. We demonstrate that nanotubes enable nanometer spatial, and femto-Newton force resolution in photonic force microscopy by accurately measuring the radiation pressure in a double frequency optical tweezers. Finally, we integrate optical trapping with Raman and photoluminescence spectroscopy demonstrating the use of a Raman and photoluminescence tweezers by investigating the spectroscopy of nanotubes and graphene flakes in solution. Experimental results are compared with calculations based on electromagnetic scattering theory.

  16. Synthesis, transfer printing, electrical and optical properties, and applications of materials composed of self-assembled, aligned single-walled carbon nanotubes

    Science.gov (United States)

    Pint, Cary L.

    Super growth of single-walled carbon nanotubes (SWNTs) has emerged as a unique method for synthesizing self-assembled, pristine, aligned SWNT materials composed of ultra-long (millimeter-long) nanotubes. This thesis focuses on novel routes of synthesizing such self-assembled SWNTs and the challenges that arise in integrating this material into next-generation applications. First of all, this work provides unique insight into growth termination of aligned SWNTs, emphasizing the mechanism that inhibits the growth of infinitely long nanotubes. Exhaustive real-time growth studies, combined with ex-situ and in-situ TEM characterization emphasizes that Ostwald ripening and subsurface diffusion of catalyst particles play a key role in growth termination. As a result, rational steps to solving this problem can enhance growth, and may ultimately lead to the meter or kilometer-long SWNTs that are necessary for a number of applications. In addition, other novel synthesis routes are discussed, such as the ability to form macroscopic fibrils of SWNTs, called "flying carpets" from 40 nm thick substrates, and the ability to achieve supergrowth of SWNTs that are controllably doped with nitrogen. In the latter case, molecular heterojunctions of doped and undoped sections in a single strand of ultralong SWNTs are demonstrated Secondly, as supergrowth is conducted on alumina coated SiO2 substrates, any applications will require that one can transfer the SWNTs to host surfaces with minimal processing. This work demonstrates a unique contact transfer route by which both patterned arrays of SWNTs, or homogenous SWNT carpets, can be transferred to any host surface. In the first case, the SWNTs are grown vertically aligned, and transferred in patterns of horizontally aligned SWNT. This transfer process relies on simple water-vapor etching of amorphous carbons at the catalyst following growth, and strong van der Waals adhesion of the high surface-area SWNT to host surfaces (gecko effect

  17. 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.

  18. Laser ablative synthesis of carbon nanotubes

    Science.gov (United States)

    Smith, Michael W.; Jordan, Kevin; Park, Cheol

    2010-03-02

    An improved method for the production of single walled carbon nanotubes that utilizes an RF-induction heated side-pumped synthesis chamber for the production of such. Such a method, while capable of producing large volumes of carbon nanotubes, concurrently permits the use of a simplified apparatus that allows for greatly reduced heat up and cool down times and flexible flowpaths that can be readily modified for production efficiency optimization. The method of the present invention utilizes a free electron laser operating at high average and peak fluence to illuminate a rotating and translating graphite/catalyst target to obtain high yields of SWNTs without the use of a vacuum chamber.

  19. In situ optical emission study on the role of C2 in the synthesis of singlewalled carbon nanotubes

    CSIR Research Space (South Africa)

    Motaung, DE

    2010-01-01

    Full Text Available applications. In this study, the authors have applied in situ optical emission spectroscopy (OES) to study the plasma in the laser-furnace method to synthesize SWCNTs. In particular, the authors have investigated the temporal and spatial behavior of C2 as well...

  20. Synthesis of Carbon Nanotube (CNT Composite Membranes

    Directory of Open Access Journals (Sweden)

    Dusan Losic

    2010-12-01

    Full Text Available Carbon nanotubes are attractive approach for designing of new membranes for advanced molecular separation because of their unique transport properties and ability to mimic biological protein channels. In this work the synthetic approach for fabrication of carbon nanotubes (CNTs composite membranes is presented. The method is based on growth of multi walled carbon nanotubes (MWCNT using chemical vapour deposition (CVD on the template of nanoporous alumina (PA membranes. The influence of experimental conditions including carbon precursor, temperature, deposition time, and PA template on CNT growth process and quality of fabricated membranes was investigated. The synthesis of CNT/PA composites with controllable nanotube dimensions such as diameters (30–150 nm, and thickness (5–100 µm, was demonstrated. The chemical composition and morphological characteristics of fabricated CNT/PA composite membranes were investigated by various characterisation techniques including scanning electron microscopy (SEM, energy-dispersive x-ray spectroscopy (EDXS, high resolution transmission electron microscopy (HRTEM and x-ray diffraction (XRD. Transport properties of prepared membranes were explored by diffusion of dye (Rose Bengal used as model of hydrophilic transport molecule.

  1. Synthesis of nano-carbon (nanotubes, nanofibres, graphene ...

    Indian Academy of Sciences (India)

    In the present study, we report the synthesis of carbon nanotubes (CNTs) using a new natural precursor: castor oil. The CNTs were synthesized by spray pyrolysis of castor oil–ferrocene solution at 850°C under an Ar atmosphere. We also report the synthesis of carbon nitrogen (C–N) nanotubes using castor ...

  2. Synthesis and characterization of boron nitrides nanotubes

    International Nuclear Information System (INIS)

    Ferreira, T.H.; Sousa, E.M.B.

    2010-01-01

    This paper presents a new synthesis for the production of boron nitride nanotubes (BNNT) from boron powder, ammonium nitrate and hematite tube furnace CVD method. The samples were subjected to some characterization techniques as infrared spectroscopy, thermal analysis, X-ray diffraction and scanning electron microscopy and transmission. By analyzing the results can explain the chemical reactions involved in the process and confirm the formation of BNNT with several layers and about 30 nanometers in diameter. Due to excellent mechanical properties and its chemical and thermal stability this material is promising for various applications. However, BNNT has received much less attention than carbon nanotubes, it is because of great difficulty to synthesize appreciable quantities from the techniques currently known, and this is one of the main reasons this work.(author)

  3. Apparatus for the laser ablative synthesis of carbon nanotubes

    Science.gov (United States)

    Smith, Michael W.; Jordan, Kevin

    2010-02-16

    An RF-induction heated side-pumped synthesis chamber for the production of carbon nanotubes. Such an apparatus, while capable of producing large volumes of carbon nanotubes, concurrently provides a simplified apparatus that allows for greatly reduced heat up and cool down times and flexible flowpaths that can be readily modified for production efficiency optimization.

  4. Doping of wide-bandgap titanium-dioxide nanotubes: optical, electronic and magnetic properties

    Science.gov (United States)

    Alivov, Yahya; Singh, Vivek; Ding, Yuchen; Cerkovnik, Logan Jerome; Nagpal, Prashant

    2014-08-01

    Doping semiconductors is an important step for their technological application. While doping bulk semiconductors can be easily achieved, incorporating dopants in semiconductor nanostructures has proven difficult. Here, we report a facile synthesis method for doping titanium-dioxide (TiO2) nanotubes that was enabled by a new electrochemical cell design. A variety of optical, electronic and magnetic dopants were incorporated into the hollow nanotubes, and from detailed studies it is shown that the doping level can be easily tuned from low to heavily-doped semiconductors. Using desired dopants - electronic (p- or n-doped), optical (ultraviolet bandgap to infrared absorption in co-doped nanotubes), and magnetic (from paramagnetic to ferromagnetic) properties can be tailored, and these technologically important nanotubes can be useful for a variety of applications in photovoltaics, display technologies, photocatalysis, and spintronic applications.Doping semiconductors is an important step for their technological application. While doping bulk semiconductors can be easily achieved, incorporating dopants in semiconductor nanostructures has proven difficult. Here, we report a facile synthesis method for doping titanium-dioxide (TiO2) nanotubes that was enabled by a new electrochemical cell design. A variety of optical, electronic and magnetic dopants were incorporated into the hollow nanotubes, and from detailed studies it is shown that the doping level can be easily tuned from low to heavily-doped semiconductors. Using desired dopants - electronic (p- or n-doped), optical (ultraviolet bandgap to infrared absorption in co-doped nanotubes), and magnetic (from paramagnetic to ferromagnetic) properties can be tailored, and these technologically important nanotubes can be useful for a variety of applications in photovoltaics, display technologies, photocatalysis, and spintronic applications. Electronic supplementary information (ESI) available: See DOI: 10.1039/c4nr02417f

  5. Designed synthesis of tunable amorphous carbon nanotubes (a ...

    Indian Academy of Sciences (India)

    Administrator

    Page 1. Electronic Supplementary Material. Graphical abstract. Designed synthesis of tunable amorphous carbon nanotubes (a-CNTs) by a novel route and their oxidation resistance properties by Longlong. Xu et al (pp 1397–1402).

  6. Synthesis of carbon nanotubes bridging metal electrodes

    International Nuclear Information System (INIS)

    Kotlar, M.; Vojs, M.; Marton, M.; Vesel, M.; Redhammer, R.

    2012-01-01

    In our work we demonstrate growth of carbon nanotubes that can conductively bridge the metal electrodes. The role of different catalysts was examined. Interdigitated metal electrodes are made from copper and we are using bimetal Al/Ni as catalyst for growth of carbon nanotubes. We are using this catalyst composition for growth of the single-walled carbon nanotube network. (authors)

  7. Carbon nanotubes from synthesis to in vivo biomedical applications.

    Science.gov (United States)

    Sajid, Muhammad Imran; Jamshaid, Usama; Jamshaid, Talha; Zafar, Nadiah; Fessi, H; Elaissari, Abdelhamid

    2016-03-30

    Owing to their unique and interesting properties, extensive research round the globe has been carried out on carbon nanotubes and carbon nanotubes based systems to investigate their practical usefulness in biomedical applications. The results from these studies demonstrate a great promise in their use in targeted drug delivery systems, diagnostic techniques and in bio-analytical applications. Although, carbon nanotubes possess quite interesting properties, which make them potential candidates in the biomedical science, but they also have some inherent properties which arise great concern regarding their biosafety. In this comprehensive review, we have discussed different aspects of carbon nanotubes and carbon nanotube based systems related to biomedical applications. In the beginning, a short historical account of these tiny yet powerful particles is given followed by discussion regarding their types, properties, methods of synthesis, large scale production method, purification techniques and characterization aspects of carbon nanotubes. In the second part of the review, the functionalization of carbon nanotubes is reviewed in detail, which is not only important to make them biocompatible and stable in biological systems but also render them a great property of loading various biomolecules, diagnostic and therapeutic moieties resulting in diversified applications. In the final part of the review, emphasis is given on the pharmacokinetic aspects of carbon nanotubes including administration routes, absorption mechanisms, distribution and elimination of carbon nanotubes based systems. Lastly, a comprehensive account about the potential biomedical applications has been given followed by insights into the future. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Synthesis and characterization of carbon nanotubes

    Science.gov (United States)

    Ritschel, Manfred; Bartsch, Karl; Leonhardt, Albrecht; Graff, Andreas; Täschner, Christine; Fink, Jörg

    2001-11-01

    The catalytic chemical vapor deposition (CCVD) is a very promising process with respect to large scale production of different kinds of carbon nanostructures. By modifying the deposition temperature, the catalyst material and the hydrocarbon nanofibers with herringbone structure, multi-walled nanotubes with tubular structure and single-walled nanotubes were deposited. Furthermore, layers of aligned multi-walled nanotubes could be obtained on oxidized silicon substrates coated with thin sputtered metal layers (Co, permalloy) as well as onto WC-Co hardmetals by using the microwave assisted plasma CVD process (MWCVD). The obtained carbon modifications were characterized by scanning (SEM) and transmission (TEM) electron microscopy. The hydrogen storage capability of the nanofibers and nanotubes and the electron field emission of the nanotube layers was investigated.

  9. Fine-Grained Targets for Laser Synthesis of Carbon Nanotubes

    Science.gov (United States)

    Smith, Michael W. (Inventor); Park, Cheol (Inventor)

    2017-01-01

    A mechanically robust, binder-free, inexpensive target for laser synthesis of carbon nanotubes and a method for making same, comprising the steps of mixing prismatic edge natural flake graphite with a metal powder catalyst and pressing the graphite and metal powder mixture into a mold having a desired target shape.

  10. Tunable Bandgap and Optical Properties of Black Phosphorene Nanotubes

    Directory of Open Access Journals (Sweden)

    Chunmei Li

    2018-02-01

    Full Text Available Black phosphorus (BP, a new two-dimensional material, has been the focus of scientists’ attention. BP nanotubes have potential in the field of optoelectronics due to their low-dimensional effects. In this work, the bending strain energy, electronic structure, and optical properties of BP nanotubes were investigated by using the first-principles method based on density functional theory. The results show that these properties are closely related to the rolling direction and radius of the BP nanotube. All the calculated BP nanotube properties show direct bandgaps, and the BP nanotubes with the same rolling direction express a monotone increasing trend in the value of bandgap with a decrease in radius, which is a stacking effect of the compression strain on the inner atoms and the tension strain on the outer atoms. The bending strain energy of the zigzag phosphorene nanotubes (zPNTs is higher than that of armchair phosphorene nanotubes (aPNT with the same radius of curvature due to the anisotropy of the BP’s structure. The imaginary part of the dielectric function, the absorption range, reflectivity, and the imaginary part of the refractive index of aPNTs have a wider range than those of zPNTs, with higher values overall. As a result, tunable BP nanotubes are suitable for optoelectronic devices, such as lasers and diodes, which function in the infrared and ultra-violet regions, and for solar cells and photocatalysis.

  11. Synthesis of Platinum Nanotubes and Nanorings via Simultaneous Metal Alloying and Etching

    KAUST Repository

    Huang, Zhiqi; Raciti, David; Yu, Shengnan; Zhang, Lei; Deng, Lin; He, Jie; Liu, Yijing; Khashab, Niveen M.; Wang, Chao; Gong, Jinlong; Nie, Zhihong

    2016-01-01

    Metallic nanotubes represent a class of hollow nanostructures with unique catalytic properties. However, the wet-chemical synthesis of metallic nanotubes remains a substantial challenge, especially for those with dimensions below 50 nm

  12. Template-mediated synthesis and bio-functionalization of flexible lignin-based nanotubes and nanowires

    Science.gov (United States)

    Caicedo, Hector M.; Dempere, Luisa A.; Vermerris, Wilfred

    2012-03-01

    Limitations of cylindrical carbon nanotubes based on the buckminsterfullerene structure as delivery vehicles for therapeutic agents include their chemical inertness, sharp edges and toxicological concerns. As an alternative, we have developed lignin-based nanotubes synthesized in a sacrificial template of commercially available alumina membranes. Lignin is a complex phenolic plant cell wall polymer that is generated as a waste product from paper mills and biorefineries that process lignocellulosic biomass into fuels and chemicals. We covalently linked isolated lignin to the inner walls of activated alumina membranes and then added layers of dehydrogenation polymer onto this base layer via a peroxidase-catalyzed reaction. By using phenolic monomers displaying different reactivities, we were able to change the thickness of the polymer layer deposited within the pores, resulting in the synthesis of nanotubes with a wall thickness of approximately 15 nm or nanowires with a nominal diameter of 200 nm. These novel nanotubes are flexible and can be bio-functionalized easily and specifically, as shown by in vitro assays with biotin and Concanavalin A. Together with their intrinsic optical properties, which can also be varied as a function of their chemical composition, these lignin-based nanotubes are expected to enable a variety of new applications including as delivery systems that can be easily localized and imaged after uptake by living cells.

  13. Template-mediated synthesis and bio-functionalization of flexible lignin-based nanotubes and nanowires

    International Nuclear Information System (INIS)

    Caicedo, Hector M; Vermerris, Wilfred; Dempere, Luisa A

    2012-01-01

    Limitations of cylindrical carbon nanotubes based on the buckminsterfullerene structure as delivery vehicles for therapeutic agents include their chemical inertness, sharp edges and toxicological concerns. As an alternative, we have developed lignin-based nanotubes synthesized in a sacrificial template of commercially available alumina membranes. Lignin is a complex phenolic plant cell wall polymer that is generated as a waste product from paper mills and biorefineries that process lignocellulosic biomass into fuels and chemicals. We covalently linked isolated lignin to the inner walls of activated alumina membranes and then added layers of dehydrogenation polymer onto this base layer via a peroxidase-catalyzed reaction. By using phenolic monomers displaying different reactivities, we were able to change the thickness of the polymer layer deposited within the pores, resulting in the synthesis of nanotubes with a wall thickness of approximately 15 nm or nanowires with a nominal diameter of 200 nm. These novel nanotubes are flexible and can be bio-functionalized easily and specifically, as shown by in vitro assays with biotin and Concanavalin A. Together with their intrinsic optical properties, which can also be varied as a function of their chemical composition, these lignin-based nanotubes are expected to enable a variety of new applications including as delivery systems that can be easily localized and imaged after uptake by living cells. (paper)

  14. Modifying the electronic and optical properties of carbon nanotubes

    Science.gov (United States)

    Kinder, Jesse M.

    The intrinsic electronic and optical properties of carbon nanotubes make them promising candidates for circuit elements and LEDs in nanoscale devices. However, applied fields and interactions with the environment can modify these intrinsic properties. This dissertation is a theoretical study of perturbations to an ideal carbon nanotube. It illustrates how transport and optical properties of carbon nanotubes can be adversely affected or intentionally modified by the local environment. The dissertation is divided into three parts. Part I analyzes the effect of a transverse electric field on the single-electron energy spectrum of semiconducting carbon nanotubes. Part II analyzes the effect of the local environment on selection rules and decay pathways relevant to dark excitons. Part III is a series of 26 appendices. Two different models for a transverse electric field are introduced in Part I. The first is a uniform field perpendicular to the nanotube axis. This model suggests the field has little effect on the band gap until it exceeds a critical value that can be tuned with strain or a magnetic field. The second model is a transverse field localized to a small region along the nanotube axis. The field creates a pair of exponentially localized bound states but has no effect on the band gap for particle transport. Part II explores the physics of dark excitons in carbon nanotubes. Two model calculations illustrate the effect of the local environment on allowed optical transitions and nonradiative recombination pathways. The first model illustrates the role of inversion symmetry in the optical spectrum. Broken inversion symmetry may explain low-lying peaks in the exciton spectrum of boron nitride nanotubes and localized photoemission around impurities and interfaces in carbon nanotubes. The second model in Part II suggests that free charge carriers can mediate an efficient nonradiative decay process for dark excitons in carbon nanotubes. The appendices in Part III

  15. Synthesis, model and stability of helically coiled carbon nanotubes

    DEFF Research Database (Denmark)

    Fejes, Dora; Raffai, Manuella; Hernadi, Klara

    2013-01-01

    . Our experiments focused on the production and development of catalysts for the synthesis of helically coiled CNTs (carbon nanotubes). The catalysts were tested in the decomposition of acetylene by CCVD (Catalytic Chemical Vapor Deposition) method. The carbon deposit was imaged by TEM (Transmission......Structural model of helically coiled carbon nanotubes is proposed. It is constructed by means of topological coordinate method. Relaxation and cohesive energy calculation are performed by molecular mechanics, using second-generation bond order potential for hydrocarbons introduced by D. W. Brenner...

  16. Boron Nitride Nanotube: Synthesis and Applications

    Science.gov (United States)

    Tiano, Amanda L.; Park, Cheol; Lee, Joseph W.; Luong, Hoa H.; Gibbons, Luke J.; Chu, Sang-Hyon; Applin, Samantha I.; Gnoffo, Peter; Lowther, Sharon; Kim, Hyun Jung; hide

    2014-01-01

    Scientists have predicted that carbon's immediate neighbors on the periodic chart, boron and nitrogen, may also form perfect nanotubes, since the advent of carbon nanotubes (CNTs) in 1991. First proposed then synthesized by researchers at UC Berkeley in the mid 1990's, the boron nitride nanotube (BNNT) has proven very difficult to make until now. Herein we provide an update on a catalyst-free method for synthesizing highly crystalline, small diameter BNNTs with a high aspect ratio using a high power laser under a high pressure and high temperature environment first discovered jointly by NASA/NIA JSA. Progress in purification methods, dispersion studies, BNNT mat and composite formation, and modeling and diagnostics will also be presented. The white BNNTs offer extraordinary properties including neutron radiation shielding, piezoelectricity, thermal oxidative stability (> 800 C in air), mechanical strength, and toughness. The characteristics of the novel BNNTs and BNNT polymer composites and their potential applications are discussed.

  17. Optical properties of armchair (7, 7) single walled carbon nanotubes

    International Nuclear Information System (INIS)

    Gharbavi, K.; Badehian, H.

    2015-01-01

    Full potential linearized augmented plane waves method with the generalized gradient approximation for the exchange-correlation potential was applied to calculate the optical properties of (7, 7) single walled carbon nanotubes. The both x and z directions of the incident photons were applied to estimate optical gaps, dielectric function, electron energy loss spectroscopies, optical conductivity, optical extinction, optical refractive index and optical absorption coefficient. The results predict that dielectric function, ε (ω), is anisotropic since it has higher peaks along z-direction than x-direction. The static optical refractive constant were calculated about 1.4 (z-direction) and 1.1 (x- direction). Moreover, the electron energy loss spectroscopy showed a sharp π electron plasmon peaks at about 6 eV and 5 eV for z and x-directions respectively. The calculated reflection spectra show that directions perpendicular to the tube axis have further optical reflection. Moreover, z-direction indicates higher peaks at absorption spectra in low range energies. Totally, increasing the diameter of armchair carbon nanotubes cause the optical band gap, static optical refractive constant and optical reflectivity to decrease. On the other hand, increasing the diameter cause the optical absorption and the optical conductivity to increase. Moreover, the sharp peaks being illustrated at optical spectrum are related to the 1D structure of CNTs which confirm the accuracy of the calculations

  18. Optical analogy. Synthesis report

    International Nuclear Information System (INIS)

    1965-01-01

    The authors report the study of conditions under which light attenuation (reflection, diffusion, absorption) and the attenuation of some radiations (notably thermal neutrons) can be described with analogical calculations. The analogy between light physical properties and neutron properties is not searched for, but the analogy between their attenuation characteristics. After having discussed this possible analogy, they propose a mathematical formulation of neutron and optical phenomena which could theoretically justify the optical analogy. The second part reports a more practical study of optics problems such as the study of simple optics materials and illumination measurements, or more precisely the study of angular distributions of optical reflections, a determination of such angular distributions, and an experimental determination of the albedo

  19. Indium telluride nanotubes: Solvothermal synthesis, growth mechanism, and properties

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Liyan [National Laboratory of Solid State Microstructures, School of Electronic Science and Engineering, Nanjing University, Nanjing 210093 (China); Yan, Shancheng, E-mail: yansc@njupt.edu.cn [National Laboratory of Solid State Microstructures, School of Electronic Science and Engineering, Nanjing University, Nanjing 210093 (China); School of Geography and Biological Information, Nanjing University of Posts and Telecommunications, Nanjing 210046 (China); Lu, Tao; Shi, Yi; Wang, Jianyu [National Laboratory of Solid State Microstructures, School of Electronic Science and Engineering, Nanjing University, Nanjing 210093 (China); Yang, Fan [School of Geography and Biological Information, Nanjing University of Posts and Telecommunications, Nanjing 210046 (China)

    2014-03-15

    A convenient solvothermal approach was applied for the first time to synthesize In{sub 2}Te{sub 3} nanotubes. The morphology of the resultant nanotubes was studied by scanning electron microscopy and transmission electron microscopy. Nanotubes with a relatively uniform diameter of around 500 nm, tube wall thickness of 50–100 nm, and average length of tens of microns were obtained. X-ray diffraction, X-ray photoelectron spectroscopy, and Raman spectroscopy were used to study the crystal structures, composition, and optical properties of the products. To understand the growth mechanism of the In{sub 2}Te{sub 3} nanotubes, we studied the influences of temperature, reaction time, and polyvinylpyrrolidone (PVP) and ethylene diamine (EDA) dosages on the final products. Based on the experimental results, a possible growth mechanism of In{sub 2}Te{sub 3} nanotubes was proposed. In this mechanism, TeO{sub 3}{sup −2} is first reduced to allow nucleation. Circumferential edges of these nucleated molecules attract further deposition, and nanotubes finally grow rapidly along the c-axis and relatively slowly along the circumferential direction. The surface area of the products was determined by BET and found to be 137.85 m{sup 2} g{sup −1}. This large surface area indicates that the nanotubes may be suitable for gas sensing and hydrogen storage applications. The nanotubes also showed broad light detection ranging from 300 nm to 1100 nm, which covers the UV–visible–NIR regions. Such excellent optical properties indicate that In{sub 2}Te{sub 3} nanotubes may enable significant advancements in new photodetection and photosensing applications. -- Graphical abstract: A convenient solvothermal approach was applied to synthesize In{sub 2}Te{sub 3} nanotubes, which has not been reported in the literature for our knowledge. Surface area of this material is 137.85 m{sup 2} g{sup −1} from the BET testing, and such a high value makes it probably suitable for gas sensing and

  20. New approach to synthesis of carbon nanotubes

    International Nuclear Information System (INIS)

    Ha, Jong Keun; Choi, Kyo Hong; Cho, Kwon Koo; Kim, Ki Won; Nam, Tae Hyun; Ahn, Hyo Jun; Ahn, Jou Hyun; Cho, Gyu Bong

    2007-01-01

    Carbon nanotubes (CNTs) have been synthesized through chemical vapor deposition in argon gas atmosphere using Fe-2.5%Mo alloyed nanoparticles as a catalyst and H 2 /CH 4 gas mixture as a reaction gas. Fe-2.5 wt.%Mo alloyed nanoparticles with average diameter of 7, 20, 45 and 85 nm are prepared by the chemical vapor condensation process using the pyrolysis of iron pentacarbonyl (Fe(CO) 5 ) and molybdenum hexacarbonyl (Mo(CO) 6 ). The morphologies of the CNTs are controlled by adjusting the nanoparticle size, reaction gas ratio and reaction temperature. With decreasing nanoparticle size under the same experimental conditions, the degree of crystalline perfection increases gradually and the morphologies of the carbon nanotubes vary from multi wall carbon nanotubes to single wall carbon nanotubes. Also, the ratio of reaction gas has an effect on the morphology and the degree of crystallinity of CNTs. In this work, it is suggested that morphology, diameter and degree of crystallinity of CNTs could be controlled by adjusting the reaction gas ratio, reaction temperature and catalyst size

  1. Cerium phosphate nanotubes: synthesis, characterization and biosensing

    Science.gov (United States)

    Meng, Ling; Yang, Lige; Zhou, Bo; Cai, Chenxin

    2009-01-01

    Cerium phosphate (CeP) nanotubes have been synthesized and confirmed by x-ray diffraction (XRD) and transmission electron microscopy (TEM). The 1D nanomaterial has a monoclinic crystal structure with a mean width of 15-20 nm and a length up to several micrometers. The nanotubes have been employed as electrode substrates for immobilization and direct electrochemistry of heme proteins/enzymes with myoglobin (Mb) as a model. The electrochemical characteristics of the Mb-CeP/GC electrode were studied by voltammetry. After being immobilized on the nanotubes, Mb can keep its natural structure and undergo effective direct electron transfer reaction with a pair of well-defined redox peaks at -(367 ± 3) mV (pH 7.5). The apparent electron transfer rate constant is (9.1 ± 1.4) s-1. The electrode displays good features in the electrocatalytic reduction of H2O2, and thus can be used as a biosensor for detecting the substrate with a low detection limit (0.5 ± 0.05 µM), a wide linear range (0.01-2 mM), high sensitivity (14.4 ± 1.2 µA mM-1), as well as good stability and reproducibility. CeP nanotubes can become a simple and effective biosensing platform for the integration of heme proteins/enzymes and electrodes, which can provide analytical access to a large group of enzymes for a wide range of bioelectrochemical applications.

  2. Cerium phosphate nanotubes: synthesis, characterization and biosensing

    International Nuclear Information System (INIS)

    Meng Ling; Yang Lige; Zhou Bo; Cai Chenxin

    2009-01-01

    Cerium phosphate (CeP) nanotubes have been synthesized and confirmed by x-ray diffraction (XRD) and transmission electron microscopy (TEM). The 1D nanomaterial has a monoclinic crystal structure with a mean width of 15-20 nm and a length up to several micrometers. The nanotubes have been employed as electrode substrates for immobilization and direct electrochemistry of heme proteins/enzymes with myoglobin (Mb) as a model. The electrochemical characteristics of the Mb-CeP/GC electrode were studied by voltammetry. After being immobilized on the nanotubes, Mb can keep its natural structure and undergo effective direct electron transfer reaction with a pair of well-defined redox peaks at -(367 ± 3) mV (pH 7.5). The apparent electron transfer rate constant is (9.1 ± 1.4) s -1 . The electrode displays good features in the electrocatalytic reduction of H 2 O 2 , and thus can be used as a biosensor for detecting the substrate with a low detection limit (0.5 ± 0.05 μM), a wide linear range (0.01-2 mM), high sensitivity (14.4 ± 1.2 μA mM -1 ), as well as good stability and reproducibility. CeP nanotubes can become a simple and effective biosensing platform for the integration of heme proteins/enzymes and electrodes, which can provide analytical access to a large group of enzymes for a wide range of bioelectrochemical applications.

  3. Temperature effects in an optical limiter using carbon nanotube suspensions

    International Nuclear Information System (INIS)

    Yu, Hyojung; Kim, Sokwon

    2005-01-01

    An optical limiter is an optical component that reduces the laser beam intensity for the protection of eyes and light sensors, and a carbon nanotube is known to be a highly efficient optical limiting material. However, the effects of heat generated by continuous use have not been studied yet. Therefore, in this work, the variation of optical limiting effect of multi-walled carbon-nanotube suspensions in several kinds of solvents such as distilled water, chloroform, ethanol and ethylene glycol, were measured in the temperature range from room temperature to the boiling point of each solvent. A pulsed Nd : YAG laser with a wavelength of 1064 nm and a pulse duration of 6 ns was used as the light source. The experimental result shows that the limiting efficiencies of all the suspensions were reduced as the temperature was increased and that a suspension with a solvent of lower boiling point, viscosity, and surface tension showed a higher efficiency.

  4. Optical Study of Liquid Crystal Doped with Multiwalled Carbon Nanotube

    Science.gov (United States)

    Gharde, Rita A.; Thakare, Sangeeta Y.

    2014-11-01

    Liquid crystalline materials have been useful for display devices i.e watches, calculators, automobile dashboards, televisions, multi media projectors etc. as well as in electro tunable lasers, optical fibers and lenses. Carbon nanotube is chosen as the main experimental factor in this study as it has been observed that Carbon Nano Tube influence the existing properties of liquid crystal host and with the doping of CNT can enhance1 the properties of LC. The combination of carbon nanotube (CNT) and liquid crystal (LC) materials show considerable interest in the scientific community due to unique physical properties of CNT in liquid crystal. Dispersion of CNTs in LCs can provide us a cheap, simple, versatile and effective means of controlling nanotube orientation on macroscopic scale with no restrictions on nanotube type. LCs have the long range orientational order rendering them to be anisotropic phases. If CNTs can be well dispersed in LC matrix, they will align with their long axes along the LC director to minimize distortions of the LC director field and the free energy. In this paper, we doped liquid crystal (Cholesteryl Nonanoate) by a small amount of multiwall carbon nanotube 0.05% and 0.1% wt. We found that by adding carbon nanotube to liquid crystals the melting point of the mixture is decreased but TNI is increased. It has been also observed that with incereas in concentration of carbon nanotube into liquid crystal shows conciderable effect on LC. The prepared samples were characterized using various techniques to study structural, thermal and optical properties i.e PMS, FPSS, UV-Vis spectroscopy, FT-IR measurements, and DTA.

  5. Synthesis of multi-walled carbon nanotubes and their application in resin based nanocomposites

    International Nuclear Information System (INIS)

    Ahmad, Shahid Nisar; Hakeem, Saira; Alvi, Rashid Ahmed; Farooq, Khawar; Farooq, Naveed; Yasmin, Farida; Saeed, Sadaf

    2013-01-01

    Multi-walled carbon nanotubes (MWCNTs) were synthesized by catalytic decomposition of hydrocarbon gas using chemical vapor deposition method. Synthesis was done at different growth temperatures and catalyst ratios. These MWCNTs were dispersed in epoxy resin (E-51) and their effect on mechanical strength of epoxy nanocomposites was studied. Increase in the mechanical strength of epoxy was observed with the addition of CNTs. The surface characterization was done by using optical microscope and scanning electron microscope (SEM). Mechanical properties were determined by the general tensile strength testing method.

  6. Synthesis and utilization of carbon nanotubes for fabrication of electrochemical biosensors

    International Nuclear Information System (INIS)

    Lawal, Abdulazeez T.

    2016-01-01

    Graphical abstract: Carbon nanotubes. - Highlights: • This review discusses synthesis and applications of carbon nanotubes sensors. • The review summarizes contributions of carbon nanotube to electrochemical biosensor. • Good electrical conductivity makes carbon nanotubes a good material for biosensors. • Carbon nanotubes promotes electron transfer that aids biosensing of biomolecules. - Abstract: This review summarizes the most recent contributions in the fabrication of carbon nanotubes-based electrochemical biosensors in recent years. It discusses the synthesis and application of carbon nanotubes to the assembly of carbon nanotube-based electrochemical sensors, its analytical performance and future expectations. An increasing number of reviews and publications involving carbon nanotubes sensors have been reported ever since the first design of carbon nanotube electrochemical biosensors. The large surface area and good electrical conductivity of carbon nanotubes allow them to act as “electron wire” between the redox center of an enzyme or protein and an electrode's surface, which make them very excellent material for the design of electrochemical biosensors. Carbon nanotubes promote the different rapid electron transfers that facilitate accurate and selective detection of cytochrome-c, β-nicotinamide adenine dinucleotide, hemoglobin and biomolecules, such as glucose, cholesterol, ascorbic acid, uric acid, dopamine pesticides, metals ions and hydrogen peroxide.

  7. Synthesis and utilization of carbon nanotubes for fabrication of electrochemical biosensors

    Energy Technology Data Exchange (ETDEWEB)

    Lawal, Abdulazeez T., E-mail: abdul.lawal@yahoo.com

    2016-01-15

    Graphical abstract: Carbon nanotubes. - Highlights: • This review discusses synthesis and applications of carbon nanotubes sensors. • The review summarizes contributions of carbon nanotube to electrochemical biosensor. • Good electrical conductivity makes carbon nanotubes a good material for biosensors. • Carbon nanotubes promotes electron transfer that aids biosensing of biomolecules. - Abstract: This review summarizes the most recent contributions in the fabrication of carbon nanotubes-based electrochemical biosensors in recent years. It discusses the synthesis and application of carbon nanotubes to the assembly of carbon nanotube-based electrochemical sensors, its analytical performance and future expectations. An increasing number of reviews and publications involving carbon nanotubes sensors have been reported ever since the first design of carbon nanotube electrochemical biosensors. The large surface area and good electrical conductivity of carbon nanotubes allow them to act as “electron wire” between the redox center of an enzyme or protein and an electrode's surface, which make them very excellent material for the design of electrochemical biosensors. Carbon nanotubes promote the different rapid electron transfers that facilitate accurate and selective detection of cytochrome-c, β-nicotinamide adenine dinucleotide, hemoglobin and biomolecules, such as glucose, cholesterol, ascorbic acid, uric acid, dopamine pesticides, metals ions and hydrogen peroxide.

  8. Synthesis-on” and “synthesis-off” modes of carbon arc operation during synthesis of carbon nanotubes

    International Nuclear Information System (INIS)

    Yatom, Shurik; Selinsky, Rachel S.

    2017-01-01

    Arc discharge synthesis of single-walled carbon nanotubes (SWCNTs) remains largely uncontrollable, due to incomplete understanding of the synthetic process itself. Here, we show that synthesis of SWCNTs by a carbon arc may not constitute a single continuous process, but may instead consist of two distinct modes. One of these, a “synthesis-on” mode, produces the majority of the nanomaterials. During the synthesis-on mode, proportionally more carbon nanotubes are collected than in another mode, a “synthesis-off” mode. Both synthesis-on and synthesis-off modes for a typical arc configuration, employing a hollow anode filled with a mixture of powdered metal catalyst and graphite, were characterized by using in situ electrical, imaging, and spectroscopic diagnostics, along with ex situ imaging and spectroscopy. The synthesis-on mode duration is rare compared to the total arc run-time, helping to explain the poor selectivity found in the final collected products, a known inadequacy of arc synthesis. Finally, the rarity of the synthesis on mode occurence may be due to the synthesis off mode being more favorable energetically.

  9. Linear Optical Response of Silicon Nanotubes Under Axial Magnetic Field

    Science.gov (United States)

    Chegel, Raad; Behzad, Somayeh

    2013-01-01

    We investigated the optical properties of silicon nanotubes (SiNTs) in the low energy region, E < 0.5 eV, and middle energy region, 1.8 eV < E < 2 eV. The dependence of optical matrix elements and linear susceptibility on radius and magnetic field, in terms of one-dimensional (1-d) wavevector and subband index, is calculated using the tight-binding approximation. It is found that, on increasing the nanotube diameter, the low-energy peaks show red-shift and their intensities are decreased. Also, we found that in the middle energy region all tubes have two distinct peaks, where the energy position of the second peak is approximately constant and independent of the nanotube diameter. Comparing the band structure of these tubes in different magnetic fields, several differences are clearly seen, such as splitting of degenerate bands, creation of additional band-edge states, and bandgap modification. It is found that applying the magnetic field leads to a phase transition in zigzag silicon hexagonal nanotubes (Si h-NTs), unlike in zigzag silicon gear-like nanotubes (Si g-NTs), which remain semiconducting in any magnetic field. We found that the axial magnetic field has two effects on the linear susceptibility spectrum, namely broadening and splitting. The axial magnetic field leads to the creation of a peak with energy less than 0.2 eV in metallic Si h-NTs, whereas in the absence of a magnetic field such a transition is not allowed.

  10. Synthesis of boron nitride nanotubes and their applications

    Directory of Open Access Journals (Sweden)

    Saban Kalay

    2015-01-01

    Full Text Available Boron nitride nanotubes (BNNTs have been increasingly investigated for use in a wide range of applications due to their unique physicochemical properties including high hydrophobicity, heat and electrical insulation, resistance to oxidation, and hydrogen storage capacity. They are also valued for their possible medical and biomedical applications including drug delivery, use in biomaterials, and neutron capture therapy. In this review, BNNT synthesis methods and the surface modification strategies are first discussed, and then their toxicity and application studies are summarized. Finally, a perspective for the future use of these novel materials is discussed.

  11. Optical absorption of zigzag single walled boron nitride nanotubes

    Science.gov (United States)

    Moradian, Rostam; Chegel, Raad; Behzad, Somayeh

    2010-11-01

    In a realistic three-dimensional model, optical matrix element and linear optical absorption of zigzag single walled boron nitride nanotubes (BNNTs) in the tight binding approximation are studied. In terms of absolute value of dipole matrix elements of the first three direct transitions at kz=0, we divided the zigzag BNNTs into three groups and investigated their optical absorption spectrum in energy ranges E7.5 eV. We found that in lower energies, E7.5 eV, their behaviors depend on their even or odd nanotube index. We also found that in the energy range 7nanotube diameter. We also found that increasing the tubes diameter leads to red shift for all peaks except ‘A’ peak where this peak moves to higher energies. Our results are in good agreement with the experimental results.

  12. Synthesis of ultra-long cadmium telluride nanotubes via combinational chemical transformation

    Energy Technology Data Exchange (ETDEWEB)

    Park, Kee-Ryung; Cho, Hong-Baek; Choa, Yong-Ho, E-mail: choa15@hanyang.ac.kr

    2017-03-01

    Synthesis of high-throughput cadmium telluride (CdTe) nanotubes with an ultra-long aspect ratio is presented via a combination process concept combined with electrospinning, electrodeposition, and cationic exchange reaction. Ultra-long sacrificial silver (Ag) nanofibers were synthesized by electrospinning involving two-step calcination, and were then electrodeposited to create silver telluride nanotubes. These nanotubes underwent cationic exchange reaction in cadmium nitrate tetrahydrate solution with the aid of a ligand, tributylphosphine (TBP). Analysis showed that ultra-long pure zinc blende CdTe nanotubes were obtained with controlled dimension and uniform morphology. The thermodynamic driving force induced by the coordination of methanol solvent and TBP attributed to overcome the kinetic barrier between Ag{sub 2}Te and CdTe nanotubes, facilitating the synthesis of CdTe nanotubes. This synthetic process involving a topotactic reaction route paves a way for high-throughput extended synthesis of new chalcogenide hollow nanotubes for application in photodetectors and solar cells. - Highlights: • High throughput synthetic route of hollow CdTe nanotubes with ultra-long aspect ratio. • Chemical combination of electrospinning, electrodeposition & cation exchange reaction. • Pure zinc blende CdTe by controlled dimension & structural variation of Ag nanofibers. • Potential for the high throughput synthesis of new exotic chalcogenide nanotubes.

  13. In situ Sn2+-incorporation synthesis of titanate nanotubes for photocatalytic dye degradation under visible light illumination

    International Nuclear Information System (INIS)

    Tsai, Chien-Cheng; Chen, Liang-Che; Yeh, Te-Fu; Teng, Hsisheng

    2013-01-01

    Highlights: ► Sn 2+ ions sensitize titanate nanotubes for photocatalysis under visible-light illumination. ► The Sn 5s orbital replaces the O 2p orbital as the top level of the valence band of titanates. ► The presence of Sn 2+ lifts the valence band of titanate nanotubes by approximately 0.9 eV. ► The doped Sn 2+ sites are active in donating photo-induced charges to dye degradation. - Abstract: Sn 2+ -incorporated titanate nanotubes, prepared by washing a layered sodium titanate with a SnCl 2 solution for tube formation, exhibit noticeable photocatalytic activity under visible light irradiation. This in situ synthesis results in a Sn/Ti ratio of approximately 0.6. Because of the introduction of Sn 2+ ions, the Sn 5s orbital replaces the O 2p orbital as the top level of the valence band of titanate nanotubes. Optical absorption analysis shows that Sn doping reduces the bandgap of titanate nanotubes from 3.5 to 2.6 eV. Oxidation of the Sn 2+ -incorporated titanate nanotubes leads to oxidation of Sn 2+ to Sn 4+ , hence, widening the bandgap. Under visible light irradiation, Sn 2+ -incorporated titanate nanotubes effectively degrade methylene blue in an aqueous solution, whereas the bare titanate nanotubes exhibit substantially lower photocatalytic activity. Photoluminescence analysis demonstrates that the induced charges from excitation of the Sn 2+ ions tend to be relaxed through chemical interactions, rather than irradiative recombination.

  14. Influence of Plasma Jet Temperature Profiles in Arc Discharge Methods of Carbon Nanotubes Synthesis.

    Science.gov (United States)

    Raniszewski, Grzegorz; Wiak, Slawomir; Pietrzak, Lukasz; Szymanski, Lukasz; Kolacinski, Zbigniew

    2017-02-23

    One of the most common methods of carbon nanotubes (CNTs) synthesis is application of an electric-arc plasma. However, the final product in the form of cathode deposit is composed of carbon nanotubes and a variety of carbon impurities. An assay of carbon nanotubes produced in arc discharge systems available on the market shows that commercial cathode deposits contain about 10% CNTs. Given that the quality of the final product depends on carbon-plasma jet parameters, it is possible to increase the yield of the synthesis by plasma jet control. Most of the carbon nanotubes are multiwall carbon nanotubes (MWCNTs). It was observed that the addition of catalysts significantly changes the plasma composition, effective ionization potential, the arc channel conductance, and in effect temperature of the arc and carbon elements flux. This paper focuses on the influence of metal components on plasma-jet forming containing carbon nanotubes cathode deposit. The plasma jet temperature control system is presented.

  15. Influence of Plasma Jet Temperature Profiles in Arc Discharge Methods of Carbon Nanotubes Synthesis

    Directory of Open Access Journals (Sweden)

    Grzegorz Raniszewski

    2017-02-01

    Full Text Available One of the most common methods of carbon nanotubes (CNTs synthesis is application of an electric-arc plasma. However, the final product in the form of cathode deposit is composed of carbon nanotubes and a variety of carbon impurities. An assay of carbon nanotubes produced in arc discharge systems available on the market shows that commercial cathode deposits contain about 10% CNTs. Given that the quality of the final product depends on carbon–plasma jet parameters, it is possible to increase the yield of the synthesis by plasma jet control. Most of the carbon nanotubes are multiwall carbon nanotubes (MWCNTs. It was observed that the addition of catalysts significantly changes the plasma composition, effective ionization potential, the arc channel conductance, and in effect temperature of the arc and carbon elements flux. This paper focuses on the influence of metal components on plasma-jet forming containing carbon nanotubes cathode deposit. The plasma jet temperature control system is presented.

  16. Synthesis and structural determination of twisted MoS2 nanotubes

    International Nuclear Information System (INIS)

    Santiago, P.; Schabes-Retchkiman, P.; Ascencio, J.A.; Mendoza, D.; Perez-Alvarez, M.; Espinosa, A.; Reza-SanGerman, C.; Camacho-Bragado, G.A.; Jose-Yacaman, M.

    2004-01-01

    In the present work we report the synthesis of MoS 2 nanotubes with diameters greater than 10 nm using a template method. The length and properties of these nanotubes are a direct result of the preparation method. High-resolution transmission electron microscopy is used to study the structure of these highly curved entities. Molecular dynamics simulations of MoS 2 nanotubes reveal that one of the stable forms of the nanotubes is a twisted one. The twisting of the nanotubes produces a characteristic contrast in the images, which is also studied using simulation methods. The analysis of the local contrast close to the perpendicular orientation shows geometrical arrays of dots in domain-like structures, which are demonstrated to be a product of the atomic overlapping of irregular curvatures in the nanotubes. The configuration of some of the experimentally obtained nanotubes is demonstrated to be twisted with a behavior suggesting partial plasticity. (orig.)

  17. Magnetic Field Effect on Ultrashort Two-dimensional Optical Pulse Propagation in Silicon Nanotubes

    Science.gov (United States)

    Konobeeva, N. N.; Evdokimov, R. A.; Belonenko, M. B.

    2018-05-01

    The paper deals with the magnetic field effect which provides a stable propagation of ultrashort pulses in silicon nanotubes from the viewpoint of their waveform. The equation is derived for the electromagnetic field observed in silicon nanotubes with a glance to the magnetic field for two-dimensional optical pulses. The analysis is given to the dependence between the waveform of ultrashort optical pulses and the magnetic flux passing through the cross-sectional area of the nanotube.

  18. Real-Time Observation of Carbon Nanotube Etching Process Using Polarized Optical Microscope.

    Science.gov (United States)

    Zhao, Qiuchen; Yao, Fengrui; Wang, Zequn; Deng, Shibin; Tong, Lianming; Liu, Kaihui; Zhang, Jin

    2017-08-01

    Controllable synthesis of carbon nanotubes (CNTs) is of great importance in its further application, which attracts broad attention. As growth and etching are the two sides in the process of material crystallography and the control of the competition between them forms the foundation for modern technology of materials design and manufacture, the understanding on etching process of carbon nanotubes is still very unclear because technically it is of great challenge to characterize the dynamics in such small one-dimensional (1D) scale. Here the real-time investigation on the etching process of CNTs is reported, by the hot-wall chemical reactor equipped with a polarized optical microscope. It is discovered that the CNT etching behavior in air is totally of random, including the etching sites, termination sites, and structure dependence. Combining with the dynamic simulation, it is revealed that the random behavior reflects the unique "self-termination" phenomenon. A structure-independent etching propagation barrier of 2.4 eV is also obtained, which indicates that the etching propagation process still follows the conventional Kinetic Wulff construction theory. The results represent the new knowledge on the etching process in carbon nanotube and can contribute to its selective enrichment. Furthermore, the "self-termination" phenomenon may be a universal behavior in 1D process. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Near-Field Scanning Optical Microscope for the Study of Polymer-Nanotube Interactions

    National Research Council Canada - National Science Library

    Carroll, David

    2000-01-01

    ... optical properties in comparison to the intrinsic polymers Recent absorption and luminescence studies of carbon nanotube composites based on electro-optic polymer hosts such as MEH-PPV, have revealed...

  20. Optical Excitation of Carbon Nanotubes Drives Localized Diazonium Reactions

    Science.gov (United States)

    2016-01-01

    Covalent chemistries have been widely used to modify carbon nanomaterials; however, they typically lack the precision and efficiency required to directly engineer their optical and electronic properties. Here, we show, for the first time, that visible light which is tuned into resonance with carbon nanotubes can be used to drive their functionalization by aryldiazonium salts. The optical excitation accelerates the reaction rate 154-fold (±13) and makes it possible to significantly improve the efficiency of covalent bonding to the sp2 carbon lattice. Control experiments suggest that the reaction is dominated by a localized photothermal effect. This light-driven reaction paves the way for precise nanochemistry that can directly tailor carbon nanomaterials at the optical and electronic levels. PMID:27588432

  1. Optical anisotropy in micromechanically rolled carbon nanotube forest

    Science.gov (United States)

    Razib, Mohd Asyraf bin Mohd; Rana, Masud; Saleh, Tanveer; Fan, Harrison; Koch, Andrew; Nojeh, Alireza; Takahata, Kenichi; Muthalif, Asan Gani Bin Abdul

    2017-09-01

    The bulk appearance of arrays of vertically aligned carbon nanotubes (VACNT arrays or CNT forests) is dark as they absorb most of the incident light. In this paper, two postprocessing techniques have been described where the CNT forest can be patterned by selective bending of the tips of the nanotubes using a rigid cylindrical tool. A tungsten tool was used to bend the vertical structure of CNTs with predefined parameters in two different ways as stated above: bending using the bottom surface of the tool (micromechanical bending (M2B)) and rolling using the side of the tool (micromechanical rolling (M2R)). The processed zone was investigated using a Field Emission Scanning Electron Microscope (FESEM) and optical setup to reveal the surface morphology and optical characteristics of the patterned CNTs on the substrate. Interestingly, the polarized optical reflection from the micromechanical rolled (M2R) sample was found to be significantly influenced by the rotation of the sample. It was observed that, if the polarization of the light is parallel to the alignment of the CNTs, the reflectance is at least 2 x higher than for the perpendicular direction. Furthermore, the reflectance varied almost linearly with good repeatability ( 10%) as the processed CNT forest sample was rotated from 0° to 90°. [Figure not available: see fulltext.

  2. Graphene and carbon nanotubes ultrafast relaxation dynamics and optics

    CERN Document Server

    Malic, Ermin

    2013-01-01

    The book introduces the reader into the ultrafast nanoworld of graphene and carbon nanotubes, including their microscopic tracks and unique optical finger prints. The author reviews the recent progress in this field by combining theoretical and experimental achievements. He offers a clear theoretical foundation by presenting transparently derived equations. Recent experimental breakthroughs are reviewed. By combining both theory and experiment as well as main results and detailed theoretical derivations, the book turns into an inevitable source for a wider audience from graduate students to researchers in physics, materials science, and electrical engineering who work on optoelectronic devices, renewable energies, or in the semiconductor industry.

  3. On the Synthesis of Carbon Nanotubes from Waste Solid Hydrocarbons

    Science.gov (United States)

    Zhuo, Chuanwei

    Carbon nanotubes (CNTs) are allotropes of carbon with a cylindrical nanostructure. They consist of coaxial tubular graphene sheets, with diameters in the order of nanometers (1 x 10-9 m) and lengths in the order of micrometers (1 x 10-6 m). The latter can now be extended into the order of meters. Carbon nanotubes (CNTs) have been studied for more than 20 years. CNTs possess superior electrical, mechanical, thermal, chemical, and structural properties, which make their potential applications nowadays overwhelmingly widespread. Now entering into the growth phase of product life cycle, increasing usage of CNTs in commercial products is part of the beginning of the nano-technological revolution. Expanding markets for CNTs' large volume applications place ever-increasing demands on lowering their production costs to the level acceptable by the end-user applications. It is estimated that the mass application of CNTs will be facilitated only when the price of CNTs approaches that of conductive carbon black. The synthesis of CNTs involves three elements: the carbonaceous feedstocks (raw materials), the catalysts, and the necessary process power consumption. Therefore, they jointly contribute to the major operation expenditures in CNT synthesis/production. Current technologies for large-scale production of CNTs (either chemical vapor deposition, CVD, or combustion synthesis) require intensive consumption of premium feedstocks and catalysts, and the CVD process requires high energy consumption. Therefore, there is a pressing need for resource-benign and energy-benign, cost-effective nano-manufacturing processes. In the search for sustainable alternatives, it would be prudent to explore renewable and/or replenishable low-cost feedstocks, such as those found in municipal, industrial, and agricultural recycling streams. In the search for low cost catalysts, stainless steels have been proposed as cost-effective dual purpose substrates and catalysts, as they contain transition

  4. Single-walled carbon nanotubes as near-infrared optical biosensors for life sciences and biomedicine.

    Science.gov (United States)

    Jain, Astha; Homayoun, Aida; Bannister, Christopher W; Yum, Kyungsuk

    2015-03-01

    Single-walled carbon nanotubes that emit photostable near-infrared fluorescence have emerged as near-infrared optical biosensors for life sciences and biomedicine. Since the discovery of their near-infrared fluorescence, researchers have engineered single-walled carbon nanotubes to function as an optical biosensor that selectively modulates its fluorescence upon binding of target molecules. Here we review the recent advances in the single-walled carbon nanotube-based optical sensing technology for life sciences and biomedicine. We discuss the structure and optical properties of single-walled carbon nanotubes, the mechanisms for molecular recognition and signal transduction in single-walled carbon nanotube complexes, and the recent development of various single-walled carbon nanotube-based optical biosensors. We also discuss the opportunities and challenges to translate this emerging technology into biomedical research and clinical use, including the biological safety of single-walled carbon nanotubes. The advances in single-walled carbon nanotube-based near-infrared optical sensing technology open up a new avenue for in vitro and in vivo biosensing with high sensitivity and high spatial resolution, beneficial for many areas of life sciences and biomedicine. Copyright © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Synthesis of Platinum Nanotubes and Nanorings via Simultaneous Metal Alloying and Etching

    KAUST Repository

    Huang, Zhiqi

    2016-04-19

    Metallic nanotubes represent a class of hollow nanostructures with unique catalytic properties. However, the wet-chemical synthesis of metallic nanotubes remains a substantial challenge, especially for those with dimensions below 50 nm. This communication describes a simultaneous alloying-etching strategy for the synthesis of Pt nanotubes with open ends by selective etching Au core from coaxial Au/Pt nanorods. This approach can be extended for the preparation of Pt nanorings when Saturn-like Au core/Pt shell nanoparticles are used. The diameter and wall thickness of both nanotubes and nanorings can be readily controlled in the range of 14-37 nm and 2-32 nm, respectively. We further demonstrated that the nanotubes with ultrathin side walls showed superior catalytic performance in oxygen reduction reaction. © 2016 American Chemical Society.

  6. Incorporation of TiO2 nanotubes in a polycrystalline zirconia: Synthesis of nanotubes, surface characterization, and bond strength.

    Science.gov (United States)

    Dos Santos, Angélica Feltrin; Sandes de Lucena, Fernanda; Sanches Borges, Ana Flávia; Lisboa-Filho, Paulo Noronha; Furuse, Adilson Yoshio

    2018-04-05

    Despite numerous advantages such as high strength, the bond of yttria-stabilized zirconia polycrystal (Y-TZP) to tooth structure requires improvement. The purpose of this in vitro study was to evaluate the incorporation of TiO 2 nanotubes into zirconia surfaces and the bond strength of resin cement to the modified ceramic. TiO 2 nanotubes were produced by alkaline synthesis, mixed with isopropyl alcohol (50 wt%) and applied on presintered zirconia disks. The ceramics were sintered, and the surfaces were characterized by confocal laser microscopy, scanning electron microscopy (SEM), and energy-dispersive x-ray spectroscopy (EDS) analysis. For bond strength, the following 6 groups (n=16) were evaluated: without TiO 2 and Single Bond Universal; with TiO 2 nanotubes and Single Bond Universal; without TiO 2 nanotubes and Z-prime; with TiO 2 nanotubes and Z-prime; without TiO 2 and Signum Zirconia Bond; with TiO 2 and Signum Zirconia Bond. After sintering, resin cement cylinders, diameter of 1.40 mm and 1 mm in height, were prepared and polymerized for 20 seconds. Specimens were stored in water at 37°C for 30 days and submitted to a shear test. Data were analyzed by 2-way ANOVA and Tukey honest significant difference (α=.05) tests. EDS analysis confirmed that nanoagglomerates were composed of TiO 2 . The shear bond strength showed statistically significant differences among bonding agents (P<.001). No significant differences were found with the application of nanotubes, regardless of the group analyzed (P=.682). The interaction among the bonding agent factors and addition of nanotubes was significant (P=.025). Nanotubes can be incorporated into zirconia surfaces. However, this incorporation did not improve bond strength. Copyright © 2017 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

  7. Synthesis of Single-walled Carbon Nanotubes Coated with Thiol-reactive Gel via Emulsion Polymerization.

    Science.gov (United States)

    Nagai, Yukiko; Tsutsumi, Yusuke; Nakashima, Naotoshi; Fujigaya, Tsuyohiko

    2018-06-15

    Single-walled carbon nanotubes (SWNTs) have unique near-infrared absorption and photoemission properties that are attractive for in vivo biological applications such as photothermal cancer treatment and bioimaging. Therefore, a smart functionalization strategy for SWNTs to create biocompatible surfaces and introduce various ligands to target active cancer cells without losing the unique optical properties of the SWNTs is strongly desired. This paper reports the de-sign and synthesis of a SWNT/gel hybrid containing maleimide groups, which react with various thiol compounds through Michael addition reactions. In this hybrid, the method called carbon nanotube micelle polymerization was used to non-covalently modify the surface of SWNTs with a cross-linked polymer gel layer. This method can form an extremely stable gel layer on SWNTs; such stability is essential for in vivo biological applications. The monomer used to form the gel layer contained a maleimide group, which was protected with furan in endo-form. The resulting hybrid was treated in water to induce deprotection via retro Diels-Alder reaction and then functionalized with thiol com-pounds through Michael addition. The functionalization of the hybrid was explored using a thiol-containing fluores-cent dye as a model thiol and the formation of the SWNT-dye conjugate was confirmed by energy transfer from the dye to SWNTs. Our strategy offers a promising SWNT-based platform for biological functionalization for cancer targeting, imaging, and treatment.

  8. Carbon nanotubes : their synthesis and integration into nanofabricated structures

    NARCIS (Netherlands)

    Druzhinina, Tamara

    2011-01-01

    The field of nanotechnology has experienced constantly increasing interest over the past decades both from industry and academy. Commonly used nanomaterials include: nanoparticles, nanowires, quantum dots, fullerenes, and carbon nanotubes. Carbon nanotubes, in particular, are promising building

  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. Method for synthesis of titanium dioxide nanotubes using ionic liquids

    Science.gov (United States)

    Qu, Jun; Luo, Huimin; Dai, Sheng

    2013-11-19

    The invention is directed to a method for producing titanium dioxide nanotubes, the method comprising anodizing titanium metal in contact with an electrolytic medium containing an ionic liquid. The invention is also directed to the resulting titanium dioxide nanotubes, as well as devices incorporating the nanotubes, such as photovoltaic devices, hydrogen generation devices, and hydrogen detection devices.

  11. 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.

  12. Applied Physics of Carbon Nanotubes Fundamentals of Theory, Optics and Transport Devices

    CERN Document Server

    Rotkin, Slava V

    2005-01-01

    The book describes the state-of-the-art in fundamental, applied and device physics of nanotubes, including fabrication, manipulation and characterization for device applications; optics of nanotubes; transport and electromechanical devices and fundamentals of theory for applications. This information is critical to the field of nanoscience since nanotubes have the potential to become a very significant electronic material for decades to come. The book will benefit all all readers interested in the application of nanotubes, either in their theoretical foundations or in newly developed characterization tools that may enable practical device fabrication.

  13. One-step synthesis of Zn doped titania nanotubes and investigation of their visible photocatalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Benjwal, Poonam [Advanced Nanoengineering Materials Laboratory, Materials Science Programme, Indian Institute of Technology Kanpur, Kanpur 208016 (India); Kar, Kamal K., E-mail: kamalkk@iitk.ac.in [Advanced Nanoengineering Materials Laboratory, Materials Science Programme, Indian Institute of Technology Kanpur, Kanpur 208016 (India); Advanced Nanoengineering Materials Laboratory, Department of Mechanical Engineering, Indian Institute of Technology Kanpur, Kanpur 208016 (India)

    2015-06-15

    Highly oriented undoped and Zn-doped titania (TiO{sub 2}) nanotubes were electrochemically fabricated by one-step anodization of titanium foil in a freshly prepared aqueous solution of zinc fluoride (ZnF{sub 2}) and ethylene glycol (EG). XRD and Raman spectroscopy unveiled the typical characteristic of anatase phase of TiO{sub 2} nanotube without any distinct dopant related peaks. SEM and AFM observation confirmed the formation of nanotubes and revealed that the Zn doping did not distort the tube morphology of TiO{sub 2}. The doping of Zn was confirmed by energy dispersive X-ray as well as X-ray photospectroscopy. Due to one-step anodization process, instead of surface doping, the Zn{sup 2+} ions were incorporated into the bulk of TiO{sub 2} nanotubes. With increasing Zn doping in nanotubes, a gradual decrease in the band gap of TiO{sub 2} (2.84 eV) was observed. Photoluminescence measurements revealed that the doping of Zn enhanced the number of charge carriers, which eventually boosted the photocatalytic activity of TiO{sub 2} nanotubes. Compared to undoped nanotubes, the as prepared Zn-doped TiO{sub 2}-nanotubes showed excellent photocatalytic activity for methylene blue degradation (reaction rate constant k = 0.19 min{sup −1}) under visible light irradiation. - Highlights: • A facile one-step anodization method is used for Zn doped TiO{sub 2}-nanotubes synthesis. • Zn{sup 2+} ions are doped into the bulk of TiO{sub 2} nanotubes. • Doped TiO{sub 2}-nanotubes unveil pure anatase phase and reduced band gap. • Compared to undoped, doped TiO{sub 2} nanotubes exhibit enhanced photocatalytic activity.

  14. Optical Performance of Carbon-Nanotube Electron Sources

    International Nuclear Information System (INIS)

    Jonge, Niels de; Allioux, Myriam; Oostveen, Jim T.; Teo, Kenneth B. K.; Milne, William I.

    2005-01-01

    The figure of merit for the electron optical performance of carbon-nanotube (CNT) electron sources is presented. This figure is given by the relation between the reduced brightness and the energy spread in the region of stable emission. It is shown experimentally that a CNT electron source exhibits a highly stable emission process that follows the Fowler-Nordheim theory for field emission, fixing the relationship among the energy spread, the current, and the radius. The performance of the CNT emitter under realistic operating conditions is compared with state-of-the-art electron point sources. It is demonstrated that the reduced brightness is a function of the tunneling parameter, a measure of the energy spread at low temperatures, only, independent of the geometry of the emitter

  15. The synthesis and filling of single-walled carbon nanotubes

    International Nuclear Information System (INIS)

    Friedrichs, Steffi

    2002-01-01

    This thesis is concerned with the synthesis, properties and application of single-walled carbon nanotubes (SWNTs). The two main objectives of the work were the development of a continuous-flow synthesis of SWNTs, using chemical vapour deposition (CVD) techniques, and the application of the hollow SWNTs as moulds for the study of the crystallisation behaviour of inorganic materials in the confined space of their inner cavity. The latter study was mainly performed by interpreting high-resolution transmission electron microscopy (HRTEM) images of the filled SWNTs. A so-called focal series restoration approach, which enhances the resolution of the images and thereby increases the information content, was employed where possible. Chapter I reviews the previous work in the field of SWNTs and introduces their basic structure, symmetry, physical and mechanical properties and the common methods of SWNT synthesis. The chapter ends with an overview of the techniques used in the present work for the characterisation of carbon nanotube samples by giving a description of the high-resolution transmission electron microscopy (HRTEM) techniques and the digital image processing method. Other physical measurement techniques used, such as Raman spectroscopy and thermogravimetric analysis (TGA), are discussed with reference to their application for the characterisation of carbon nanotubes. Chapter II describes the development of an improved synthesis strategy for SWNTs. A continuous-flow chemical vapour deposition (CVD) method was explored using carbon monoxide or mixtures of methane and hydrogen as the carbon feedstock gas and introducing various volatile organometallic compounds to catalyse the formation of SWNTs. In this study, a special water-cooled copper nozzle was designed and built so as to prevent the premature decompositiont (disproportionation) of the reactants (the carbon monoxide gas) and to allow their direct introduction into the centre of the hot reaction zone. A

  16. Non-damaging and scalable carbon nanotube synthesis on carbon fibres

    OpenAIRE

    De Luca, H; Anthony, DB; Qian, H; Greenhalgh, E; Bismarck, A; Shaffer, M

    2016-01-01

    The growth of carbon nanotubes (CNTs) on carbon fibres (CFs) to produce a hierarchical fibre with two differing reinforcement length scales, in this instance nanometre and micrometre respectively, is considered a route to improve current state-of-the-art fibre reinforced composites [1]. The scalable production of carbon nanotube-grafted-carbon fibres (CNT-g-CFs) has been limited due to high temperatures, the use of flammable gases and the requirement of inert conditions for CNT synthesis, whi...

  17. Novel Catalyst for the Chirality Selective Synthesis of Single Walled Carbon Nanotubes

    Science.gov (United States)

    2015-05-12

    Final 3. DATES COVERED (From - To) 03-April-2013 to 02-April-2015 4. TITLE AND SUBTITLE Novel Catalyst for the Chirality Selective...Distribution is unlimited. 13. SUPPLEMENTARY NOTES 14. ABSTRACT Chiral single walled carbon nanotubes (SWCNTs) are known to possess unique... chirality control in SWCNT synthesis. A model catalyst based on CoSO4/SiO2 was developed that showed good selectivity to (9,8) nanotubes. Remote plasma

  18. Fabrication of spintronics device by direct synthesis of single-walled carbon nanotubes from ferromagnetic electrodes

    Directory of Open Access Journals (Sweden)

    Mohd Ambri Mohamed, Nobuhito Inami, Eiji Shikoh, Yoshiyuki Yamamoto, Hidenobu Hori and Akihiko Fujiwara

    2008-01-01

    Full Text Available We describe an alternative method for realizing a carbon nanotube spin field-effect transistor device by the direct synthesis of single-walled carbon nanotubes (SWNTs on substrates by alcohol catalytic chemical vapor deposition. We observed hysteretic magnetoresistance (MR at low temperatures due to spin-dependent transport. In these devices, the maximum ratio in resistance variation of MR was found to be 1.8%.

  19. Carbon Nanotubes Advanced Topics in the Synthesis, Structure, Properties and Applications

    CERN Document Server

    Jorio, Ado; Dresselhaus, Mildred S

    2008-01-01

    The carbon nanotubes field has evolved substantially since the publication of the bestseller "Carbon Nanotubes: Synthesis, Structure, Properties and Applications". The present volume builds on the generic aspects of the aforementioned book, which emphasizes the fundamentals, with the new volume emphasizing areas that have grown rapidly since the first volume, guiding future directions where research is needed and highlighting applications. The volume also includes an emphasis on areas like graphene, other carbon-like and other tube-like materials because these fields are likely to affect and influence developments in nanotubes in the next 5 years.

  20. Ethanol flame synthesis of carbon nanotubes in deficient oxygen environments

    Science.gov (United States)

    Hu, Wei-Chieh; Lin, Ta-Hui

    2016-04-01

    In this study, carbon nanotubes (CNTs) were synthesized using ethanol diffusion flames in a stagnation-flow system composed of an upper oxidizer duct and a lower liquid pool. In the experiments, a gaseous mixture of oxygen and nitrogen flowed from the upper oxidizer duct, and then impinged onto the vertically aligned ethanol pool to generate a planar and steady diffusion flame in a deficient oxygen environment. A nascent nickel mesh was used as the catalytic metal substrate to collect deposited materials. The effect of low oxygen concentration on the formation of CNTs was explored. The oxygen concentration significantly influenced the flame environment and thus the synthesized carbon products. Lowering the oxygen concentration increased the yield, diameter, and uniformity of CNTs. The optimal operating conditions for CNT synthesis were an oxygen concentration in the range of 15%-19%, a flame temperature in the range of 460 °C-870 °C, and a sampling position of 0.5-1 mm below the upper edge of the blue flame front. It is noteworthy that the concentration gradient of C2 species and CO governed the CNT growth directly. CNTs were successfully fabricated in regions with uniform C2 species and CO distributions.

  1. Hydrothermal synthesis of sodium titanate nanotubes; Hydrotermalna synteza nanorurok titanatu sodneho

    Energy Technology Data Exchange (ETDEWEB)

    Miskoci, M.; Jesenak, K. [Univerzita Komenskeho, Prirodovedecka fakulta, Katedra anorganickej chemie, 84215 Bratislava (Slovakia); Caplovicova, M. [Univerzita Komenskeho, Prirodovedecka fakulta, Katedra loziskovej geologie, 84215 Bratislava (Slovakia)

    2013-04-16

    From suspension of nanoparticles TiO{sub 2} in concentrated water solution of NaOH were prepared by hydrothermal synthesis sodium titanates particles with different shapes. Influence of synthesis duration under temperature 180 grad C on the change of particles shapes was observed. The result of experiment showed that one day synthesis resulted to obtained product with high content of nanotubes, but the extension of this period led to the transformation of product's shape into stripes. From the results of experiment follows that as a precursor for TiO{sub 2} nanotubes preparation may be used only products of hydrothermal synthesis, which duration of pressure synthesis was not longer than 24 hours. (authors)

  2. Geometry, electronic structures and optical properties of phosphorus nanotubes

    International Nuclear Information System (INIS)

    Hu, Tao; Hashmi, Arqum; Hong, Jisang

    2015-01-01

    Using a first principles approach, we investigated the geometry, electronic structures, and optical properties of phosphorus nanotubes (PNTs). Two possible 1D configurations, the so-called α-PNTs and β-PNTs, are proposed, which are structurally related to blue and black phosphorus monolayers, respectively. Hereby, we predict that both armchair and zigzag geometries can be synthesized in α-PNTs, but the zigzag form of β-PNT is highly unfavorable because of large strain and conformation energies. The band gap of α-PNTs is expected to be ∼2.67 eV, and this is insensitive to the chirality when the tube’s inner diameter is larger than 1.3 nm, while the armchair β-PNTs have a much smaller band gap. Interestingly, we find nearly flat band structures in the zigzag α-PNT system. This may indicate that an excited particle–hole pair has a huge effective mass. We also find asymmetric optical properties with respect to the polarization direction. The armchair α-PNT for parallel polarization shows a large refractive index of 2.6 near the ultraviolet wavelength, and also we find that the refractive index can be even smaller than 1 in certain frequency ranges. The zigzag tubes show very weak reflectivity for parallel polarization, while the armchair tube displays high reflectivity. (paper)

  3. Ultrasensitive mass sensing with nonlinear optics in a doubly clamped suspended carbon nanotube resonator

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Hua-Jun; Zhu, Ka-Di [Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, 800 DongChuan Road, Shanghai 2 00240 (China)

    2013-12-07

    Nanomechanical resonator makes itself as an ideal system for ultrasensitive mass sensing due to its ultralow mass and high vibrational frequency. The mass sensing principle is due to the linear relationship of the frequency-shift and mass-variation. In this work, we will propose a nonlinear optical mass sensor based on a doubly clamped suspended carbon nanotube resonator in all-optical domain. The masses of external particles (such as nitric oxide molecules) landing onto the surface of carbon nanotube can be determined directly and accurately via using the nonlinear optical spectroscopy. This mass sensing proposed here may provide a nonlinear optical measurement technique in quantum measurements and environmental science.

  4. EFFECTS OF SYNTHESIS PARAMETERS ON THE STRUCTURE OF TITANIA NANOTUBES

    Directory of Open Access Journals (Sweden)

    M. NORANI MUTI

    2008-08-01

    Full Text Available Detection of hydrogen is crucial for industrial process control and medical applications where presence of hydrogen in breath indicates different type of health problems particularly in infants. A better performed sensor with high sensitivity, selectivity, reliability and faster response time would be critical and sought after especially for medical applications. Titanium dioxide nanotube structure is chosen as an active component in the gas sensor because of its highly sensitive electrical resistance to hydrogen over a wide range of concentrations. The objective of the work is to investigate the effect of the anodizing conditions on the structure of titania nanotubes produced by anodizing method. The anodizing parameters namely the ambient temperature and separation of electrodes are varied accordingly to find the optimum anodizing conditions for production of good quality titania nanotubes for enhanced properties based on their uniformity, coverage, pore size and crystallinity. Samples of nanotubes produced were subjected to annealing process at varying time and temperature in order to improve the crystallinity of the nanotubes. The highly ordered porous titania nanotubes produced by this method are of tabular shape and have good uniformity and alignment over large areas. The pore size of the titania nanotubes ranges from 47 to 94 nm, while the wall thickness is in the range of 17 to 26 nm. The length of the nanotubes was found to be about 280 nm. The structure of nanotubes changes from amorphous to crystalline after undergoing annealing treatment. Nanotubes have also shown to have better crystallinity if they were subjected to annealing treatment at higher temperature. The characteristics of nanotubes obtained are found to be agreeable to those that have been reported to show improved hydrogen gas sensing properties.

  5. Nitrogen doped carbon nanotubes : synthesis, characterization and catalysis

    NARCIS (Netherlands)

    van Dommele, S.

    2008-01-01

    Nitrogen containing Carbon Nanotubes (NCNT) have altered physical- and chemical properties with respect to polarity, conductivity and reactivity as compared to conventional carbon nanotubes (CNT) and have potential for use in electronic applications or catalysis. In this thesis the incorporation of

  6. Synthesis of self-organized TiO{sub 2} nanotube arrays: Microstructural, stereoscopic, and topographic studies

    Energy Technology Data Exchange (ETDEWEB)

    Quiroz, Heiddy P., E-mail: hpquirozg@unal.edu.co; Dussan, A., E-mail: adussanc@unal.edu.co [Department of Physis, Grupo de Materiales Nanoestructurados y sus Aplicaciones, Universidad Nacional de Colombia, Bogotá 11001 (Colombia)

    2016-08-07

    In this work, titanium dioxide nanotubes were prepared by using titanium foils via electrochemical anodization in ethylene glycol solutions containing different amounts of water and fluoride in the ranges of 1%–3% and 0.15%–0.5%, respectively, to determine their effects on morphology, optical, and crystalline structure properties. Annealing processes were performed on all samples in the range between 273 and 723 K. Morphology and structure properties of the samples were studied by scanning electron microscopy, X-ray diffraction (XRD), and transmission electron microscopy. Titanium dioxide (TiO{sub 2}) nanotubes, through anodization method, are strongly influenced by conditions, like fluoride concentration and applied voltages. Tube lengths between 2 and 7 μm were obtained, exhibiting different diameters and wall thicknesses. When alternating voltage was applied, the outer surface of the nanotubes exhibited evenly spaced ring-shaped regions, while smooth tubes were observed when constant voltage was applied. Reflection peaks, corresponding to Brookite, Anatase, and Rutile, of TiO{sub 2} phases, were observed from the XRD pattern. These phases were corroborated via μXRD measurements, and the Ti{sub 3}O{sub 5} phase was also observed in detail. Absorption coefficient (α), optical band gap (Eg), and extinction coefficient (ε) of TiO{sub 2} nanotubes were calculated by transmittance spectra in the UV–Vis range. Strong absorption was noted in the UV region from reflectance and absorbance measurements. A correlation between synthesis parameters and physical properties is presented.

  7. Rare-earth doped boron nitride nanotubes: Synthesis and characterization

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Wellington Marcos; Sousa, Edesia Martins Barros de, E-mail: wellingtonmarcos@yahoo.com.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2016-07-01

    Full text: Boron nitride is a heat and chemically resistant refractory compound of boron and nitrogen atoms with the chemical formula BN. This structure exists in various crystalline forms that are isoelectronic to a similarly structured carbon lattice. The hexagonal form (h-BN) corresponding to graphite is the most stable and soft among BN polymorph. However, boron nitride nanotubes (BNNTs) were first time synthesized in 1995 [1] and have a type of one-dimensional (1D) nanostructure. Recently the BNNTs have attracted significant interest for scientific and technological applications due to their Wide bandgap. The Wide-bandgap semiconductors doped with rare-earth are considered as a new type of luminescent material, combining special Wide bandgap semiconducting properties with the rare-earth luminescence feature. BNNTs have a stable wide bandgap of 5.5 eV and super thermal and chemical stabilities, which make BNNTs an ideal nanosized luminescent material [2]. In this study, we report a simple and efficient route for the synthesis of BNNTs doped with samarium and europium. High quality BNNTs doped was produced via CVD technique using NH{sub 3} and N{sub 2} gases as source. Boron amorphous, catalyst and oxides rare-earth powder were used as precursor. Detailed studies involving energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), Raman spectroscopy, Fourier-transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and transmission electron microscope (TEM) were performed in order to characterize the BNNTs as grown. [1] Chopra, N. G.; Luyken, R. J. et al. Science, v. 269, p. 966-967, 1995. [2] Chen, H.; Chen, Y. et al. Adv. Matter. v. 19, p. 1845-1848, 2007. (author)

  8. Rare-earth doped boron nitride nanotubes: Synthesis and characterization

    International Nuclear Information System (INIS)

    Silva, Wellington Marcos; Sousa, Edesia Martins Barros de

    2016-01-01

    Full text: Boron nitride is a heat and chemically resistant refractory compound of boron and nitrogen atoms with the chemical formula BN. This structure exists in various crystalline forms that are isoelectronic to a similarly structured carbon lattice. The hexagonal form (h-BN) corresponding to graphite is the most stable and soft among BN polymorph. However, boron nitride nanotubes (BNNTs) were first time synthesized in 1995 [1] and have a type of one-dimensional (1D) nanostructure. Recently the BNNTs have attracted significant interest for scientific and technological applications due to their Wide bandgap. The Wide-bandgap semiconductors doped with rare-earth are considered as a new type of luminescent material, combining special Wide bandgap semiconducting properties with the rare-earth luminescence feature. BNNTs have a stable wide bandgap of 5.5 eV and super thermal and chemical stabilities, which make BNNTs an ideal nanosized luminescent material [2]. In this study, we report a simple and efficient route for the synthesis of BNNTs doped with samarium and europium. High quality BNNTs doped was produced via CVD technique using NH 3 and N 2 gases as source. Boron amorphous, catalyst and oxides rare-earth powder were used as precursor. Detailed studies involving energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), Raman spectroscopy, Fourier-transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and transmission electron microscope (TEM) were performed in order to characterize the BNNTs as grown. [1] Chopra, N. G.; Luyken, R. J. et al. Science, v. 269, p. 966-967, 1995. [2] Chen, H.; Chen, Y. et al. Adv. Matter. v. 19, p. 1845-1848, 2007. (author)

  9. Electrochemical synthesis of self-organized TiO2 crystalline nanotubes without annealing

    Science.gov (United States)

    Giorgi, Leonardo; Dikonimos, Theodoros; Giorgi, Rossella; Buonocore, Francesco; Faggio, Giuliana; Messina, Giacomo; Lisi, Nicola

    2018-03-01

    This work demonstrates that upon anodic polarization in an aqueous fluoride-containing electrolyte, TiO2 nanotube array films can be formed with a well-defined crystalline phase, rather than an amorphous one. The crystalline phase was obtained avoiding any high temperature annealing. We studied the formation of nanotubes in an HF/H2O medium and the development of crystalline grains on the nanotube wall, and we found a facile way to achieve crystalline TiO2 nanotube arrays through a one-step anodization. The crystallinity of the film was influenced by the synthesis parameters, and the optimization of the electrolyte composition and anodization conditions (applied voltage and time) were carried out. For comparison purposes, crystalline anatase TiO2 nanotubes were also prepared by thermal treatment of amorphous nanotubes grown in an organic bath (ethylene glycol/NH4F/H2O). The morphology and the crystallinity of the nanotubes were studied by field emission gun-scanning electron microscopy (FEG-SEM) and Raman spectroscopy, whereas the electrochemical and semiconducting properties were analyzed by means of linear sweep voltammetry, impedance spectroscopy, and Mott-Schottky plots. X-ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS) allowed us to determine the surface composition and the electronic structure of the samples and to correlate them with the electrochemical data. The optimal conditions to achieve a crystalline phase with high donor concentration are defined.

  10. Facile and template-free method toward chemical synthesis of polyaniline film/nanotube structures

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Pei [Department of Electrical and Computer Engineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh Pennsylvania 15261; Zhu, Yisi [Materials Science Division, Argonne National Lab, Lemont Illinois 60439; Torres, Jorge [Department of Electrical and Computer Engineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh Pennsylvania 15261; Lee, Seung Hee [Department of BIN Fusion Technology, Chonbuk National University, Jeonju 561-786 Korea; Yun, Minhee [Department of Electrical and Computer Engineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh Pennsylvania 15261

    2017-09-05

    A facile and template-free method is reported to synthesize a new thin film structure: polyaniline (PANI) film/nanotubes (F/N) structure. The PANI F/N is a 100-nm thick PANI film embedded with PANI nanotubes. This well-controlled method requires no surfactant or organic acid as well as relatively low concentration of reagents. Synthesis condition studies reveal that aniline oligomers with certain structures are responsible for guiding the growth of the nanotubes. Electrical characterization also indicates that the PANI F/N possesses similar field-effect transistor characteristics to bare PANI film. With its 20% increased surface-area-to-volume (S/V) ratio contributed by surface embedded nanotubes and the excellent p-type semiconducting characteristic, PANI F/N shows clear superiority compared with bare PANI film. Such advantages guarantee the PANI F/N a promising future toward the development of ultra-high sensitivity and low-cost biosensors.

  11. Synthesis of CdTe QDs/single-walled aluminosilicate nanotubes hybrid compound and their antimicrobial activity on bacteria

    Science.gov (United States)

    Geraldo, Daniela A.; Arancibia-Miranda, Nicolás; Villagra, Nicolás A.; Mora, Guido C.; Arratia-Perez, Ramiro

    2012-12-01

    The use of molecular conjugates of quantum dots (nanocrystalline fluorophores) for biological purposes have received much attention due to their improved biological activity. However, relatively, little is known about the synthesis and application of aluminosilicate nanotubes decorated with quantum dots (QDs) for imaging and treatment of pathogenic bacteria. This paper describes for a first time, the use of single-walled aluminosilicate nanotubes (SWNT) (imogolite) as a one-dimensional template for the in situ growth of mercaptopropionic acid-capped CdTe QDs. This new nanohybrid hydrogel was synthesized by a simple reaction pathway and their enhanced optical properties were monitored by fluorescence and UV-Vis spectroscopy, confirming that the use of these nanotubes favors the confinement effects of net CdTe QDs. In addition, studies of FT-IR spectroscopy and transmission electron microscopy confirmed the non-covalent functionalization of SWNT. Finally, the antimicrobial activity of SWNT coated with CdTe QDs toward three opportunistic multi-resistant pathogens such as Salmonella typhimurium, Acinetobacter baumannii, and Pseudomonas aeruginosa were tested. Growth inhibition tests were conducted by exposing growing bacteria to CdTe QDs/SWNT hybrid compound showing that the new nano-structured composite is a potential antimicrobial agent for heavy metal-resistant bacteria.

  12. Synthesis of CdTe QDs/single-walled aluminosilicate nanotubes hybrid compound and their antimicrobial activity on bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Geraldo, Daniela A., E-mail: daniela.geraldo@unab.cl [Universidad Andres Bello, Departamento de Ciencias Quimicas (Chile); Arancibia-Miranda, Nicolas [CEDENNA, Center for the Development of Nanoscience and Nanotechnology (Chile); Villagra, Nicolas A. [Universidad Andres Bello, Laboratorio de Microbiologia, Facultad de Ciencias Biologicas (Chile); Mora, Guido C. [Universidad Andres Bello, Unidad de Microbiologia, Facultad de Medicina (Chile); Arratia-Perez, Ramiro [Universidad Andres Bello, Departamento de Ciencias Quimicas (Chile)

    2012-12-15

    The use of molecular conjugates of quantum dots (nanocrystalline fluorophores) for biological purposes have received much attention due to their improved biological activity. However, relatively, little is known about the synthesis and application of aluminosilicate nanotubes decorated with quantum dots (QDs) for imaging and treatment of pathogenic bacteria. This paper describes for a first time, the use of single-walled aluminosilicate nanotubes (SWNT) (imogolite) as a one-dimensional template for the in situ growth of mercaptopropionic acid-capped CdTe QDs. This new nanohybrid hydrogel was synthesized by a simple reaction pathway and their enhanced optical properties were monitored by fluorescence and UV-Vis spectroscopy, confirming that the use of these nanotubes favors the confinement effects of net CdTe QDs. In addition, studies of FT-IR spectroscopy and transmission electron microscopy confirmed the non-covalent functionalization of SWNT. Finally, the antimicrobial activity of SWNT coated with CdTe QDs toward three opportunistic multi-resistant pathogens such as Salmonella typhimurium, Acinetobacter baumannii, and Pseudomonas aeruginosa were tested. Growth inhibition tests were conducted by exposing growing bacteria to CdTe QDs/SWNT hybrid compound showing that the new nano-structured composite is a potential antimicrobial agent for heavy metal-resistant bacteria.

  13. Synthesis of CdTe QDs/single-walled aluminosilicate nanotubes hybrid compound and their antimicrobial activity on bacteria

    International Nuclear Information System (INIS)

    Geraldo, Daniela A.; Arancibia-Miranda, Nicolás; Villagra, Nicolás A.; Mora, Guido C.; Arratia-Perez, Ramiro

    2012-01-01

    The use of molecular conjugates of quantum dots (nanocrystalline fluorophores) for biological purposes have received much attention due to their improved biological activity. However, relatively, little is known about the synthesis and application of aluminosilicate nanotubes decorated with quantum dots (QDs) for imaging and treatment of pathogenic bacteria. This paper describes for a first time, the use of single-walled aluminosilicate nanotubes (SWNT) (imogolite) as a one-dimensional template for the in situ growth of mercaptopropionic acid-capped CdTe QDs. This new nanohybrid hydrogel was synthesized by a simple reaction pathway and their enhanced optical properties were monitored by fluorescence and UV–Vis spectroscopy, confirming that the use of these nanotubes favors the confinement effects of net CdTe QDs. In addition, studies of FT-IR spectroscopy and transmission electron microscopy confirmed the non-covalent functionalization of SWNT. Finally, the antimicrobial activity of SWNT coated with CdTe QDs toward three opportunistic multi-resistant pathogens such as Salmonella typhimurium, Acinetobacter baumannii, and Pseudomonas aeruginosa were tested. Growth inhibition tests were conducted by exposing growing bacteria to CdTe QDs/SWNT hybrid compound showing that the new nano-structured composite is a potential antimicrobial agent for heavy metal-resistant bacteria.

  14. Synthesis and Growth Mechanism of Ni Nanotubes and Nanowires

    Directory of Open Access Journals (Sweden)

    Wang Yiqian

    2009-01-01

    Full Text Available Abstract Highly ordered Ni nanotube and nanowire arrays were fabricated via electrodeposition. The Ni microstructures and the process of the formation were investigated using conventional and high-resolution transmission electron microscope. Herein, we demonstrated the systematic fabrication of Ni nanotube and nanowire arrays and proposed an original growth mechanism. With the different deposition time, nanotubes or nanowires can be obtained. Tubular nanostructures can be obtained at short time, while nanowires take longer time to form. This formation mechanism is applicable to design and synthesize other metal nanostructures and even compound nanostuctures via template-based electrodeposition.

  15. Design and optimization of carbon-nanotube-material/dielectric hybrid nonlinear optical waveguides

    International Nuclear Information System (INIS)

    Zhao, Xin; Zheng, Zheng; Lu, Zhiting; Zhu, Jinsong; Zhou, Tao

    2011-01-01

    The nonlinear optical characteristics of highly nonlinear waveguides utilizing carbon nanotube composite materials are investigated theoretically. The extremely high nonlinearity and relatively high loss of the carbon nanotube materials are shown to greatly affect the performance of such waveguides for nonlinear optical applications, in contrast to waveguides using conventional nonlinear materials. Different configurations based on applying the carbon nanotube materials to the popular ridge and buried waveguides are thoroughly studied, and the optimal geometries are derived through simulations. It is shown that, though the nonlinear coefficient is often huge for these waveguides, the loss characteristics can significantly limit the maximum achievable accumulated nonlinearity, e.g. the maximum nonlinear phase shift. Our results suggest that SOI-based high-index-contrast, carbon nanotube cladding waveguides, rather than the currently demonstrated low-contrast waveguides, could hold the promise of achieving significantly higher accumulated nonlinearity

  16. Alcohol detection using carbon nanotubes acoustic and optical sensors

    Science.gov (United States)

    Penza, M.; Cassano, G.; Aversa, P.; Antolini, F.; Cusano, A.; Cutolo, A.; Giordano, M.; Nicolais, L.

    2004-09-01

    We demonstrate the integration of single-walled carbon nanotubes (SWCNTs) onto quartz crystal microbalance (QCM) and standard silica optical fiber (SOF) sensor for alcohol detection at room temperature. Different transducing mechanisms have been used in order to outline the sensing properties of this class of nanomaterials, in particular the attention has been focused on two key parameters in sensing applications: mass and refractive index changes due to gas absorption. Here, Langmuir-Blodgett (LB) films consisting of tangled bundles of SWCNTs without surfactant molecules have been successfully transferred onto QCM and SOF. Mass-sensitive 10MHz QCM SWCNTs sensor exhibited a resonant frequency decreasing upon tested alcohols exposure; also the normalized optoelectronic signal (λ=1310nm) of the refractive index-sensitive SOF SWCNTs sensor was found to decrease upon alcohols ambient. Highly sensitive, repeatable and reversible responses of the QCM and SOF SWCNTs sensors indicate that the detection, at room temperature, in a wide mmHg vapor pressures range of alcohols and potentially other volatile organic compounds is feasible.

  17. Optical absorption and thermal transport of individual suspended carbon nanotube bundles.

    Science.gov (United States)

    Hsu, I-Kai; Pettes, Michael T; Bushmaker, Adam; Aykol, Mehmet; Shi, Li; Cronin, Stephen B

    2009-02-01

    A focused laser beam is used to heat individual single-walled carbon nanotube bundles bridging two suspended microthermometers. By measurement of the temperature rise of the two thermometers, the optical absorption of 7.4-10.3 nm diameter bundles is found to be between 0.03 and 0.44% of the incident photons in the 0.4 microm diameter laser spot. The thermal conductance of the bundle is obtained with the additional measurement of the temperature rise of the nanotubes in the laser spot from shifts in the Raman G band frequency. According to the nanotube bundle diameter determined by transmission electron microscopy, the thermal conductivity is obtained.

  18. Synthesis of Carbon Nanotube-Inorganic Hybrid Nanocomposites: An Instructional Experiment in Nanomaterials Chemistry

    Science.gov (United States)

    de Dios, Miguel; Salgueirino, Veronica; Perez-Lorenzo, Moises; Correa-Duarte, Miguel A.

    2012-01-01

    An experiment is described to introduce advanced undergraduate students to an exciting area of nanotechnology that incorporates nanoparticles onto carbon nanotubes to produce systems that have valuable technological applications. The synthesis of such material has been easily achieved through a simple three-step procedure. Students explore…

  19. Three-dimensional ultrashort optical Airy beams in an inhomogeneous medium with carbon nanotubes

    Science.gov (United States)

    Zhukov, Alexander V.; Bouffanais, Roland; Belonenko, Mikhail B.; Dvuzhilov, Ilya S.

    2017-03-01

    In this Letter, we consider the problem of the dynamics of propagation of three-dimensional optical pulses (a.k.a. light bullets) with an Airy profile through a heterogeneous environment of carbon nanotubes. We show numerically that such beams exhibit sustained and stable propagation. Moreover, we demonstrate that by varying the density modulation period of the carbon nanotubes one can indirectly control the pulse velocity, which is a particularly valuable feature for the design and manufacturing of novel pulse delay devices.

  20. Optically and biologically active mussel protein-coated double-walled carbon nanotubes.

    Science.gov (United States)

    Jung, Yong Chae; Muramatsu, Hiroyuki; Fujisawa, Kazunori; Kim, Jin Hee; Hayashi, Takuya; Kim, Yoong Ahm; Endo, Morinobu; Terrones, Mauricio; Dresselhaus, Mildred S

    2011-12-02

    A method of dispersing strongly bundled double-walled carbon nanotubes (DWNTs) via a homogeneous coating of mussel protein in an aqueous solution is presented. Optical activity, mechanical strength, as well as electrical conductivity coming from the nanotubes and the versatile biological activity from the mussel protein make mussel-coated DWNTs promising as a multifunctional scaffold and for anti-fouling materials. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Optical and photocatalytic properties of indium phosphide nanoneedles and nanotubes

    DEFF Research Database (Denmark)

    Yu, Yanlong; Yu, Cuiyan; Xu, Tao

    2017-01-01

    , and Ultraviolet-visible (UV–vis) spectroscopy. The room temperature photoluminescence (PL) measurements showed that the InP nanoneedles and nanotubes possessed a pronounced blue shift in contrast to the bulk counterpart, which was ascribed to the crystalline defects effect. Moreover, the InP nanotubes exhibited...

  2. Templated synthesis of metal nanorods in silica nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Yin, Yadong; Gao, Chuanbo

    2018-04-10

    A method of preparing a metal nanorod. The method includes seeding a metal nanoparticle within the lumen of a nanotube, and growing a metal nanorod from the seeded metal nanoparticle to form a metal nanorod-nanotube composite. In some cases, the nanotube includes metal binding ligands attached to the inner surface. Growing of the metal nanorod includes incubating the seeded nanotube in a solution that includes: a metal source for the metal in the metal nanorod, the metal source including an ion of the metal; a coordinating ligand that forms a stable complex with the metal ion; a reducing agent for reducing the metal ion, and a capping agent that stabilizes atomic monomers of the metal. Compositions derived from the method are also provided.

  3. Synthesis of carbon nanotubes by catalytic vapor decomposition ...

    Indian Academy of Sciences (India)

    Carbon nanotubes (CNTs); catalytic vapor decomposition; soap bubble mass flowmeter. ... [4,13,14], makes them an excellent candidate for use as a dielectric in supercapac- itors [15]. ... the change in liquid level in the scrubber. After the ...

  4. Synthesis of cadmium chalcogenide nanotubes at room temperature

    KAUST Repository

    Pan, Jun

    2012-10-01

    Cadmium chalcogenide (CdE, E=S, Se, Te) polycrystalline nanotubes have been synthesized from precursor of CdS/cadmium thiolate complex at room temperature. The precursor was hydrothermally synthesized at 180 °C using thioglycolic acid (TGA) and cadmium acetate as starting materials. The transformation from the rod-like precursor of CdS/cadmium thiolate complex to CdS, CdSe and CdTe nanotubes were performed under constant stirring at room temperature in aqueous solution containing S 2-, Se 2- and Te 2-, respectively. The nanotube diameter can be controlled from 150 to 400 nm related to the dimension of templates. The XRD patterns show the cadmium chalcogenide nanotubes all corresponding to face-centered cubic structure. © 2012 Elsevier B.V. All rights reserved.

  5. Synthesis of cadmium chalcogenide nanotubes at room temperature

    KAUST Repository

    Pan, Jun; Qian, Yitai

    2012-01-01

    Cadmium chalcogenide (CdE, E=S, Se, Te) polycrystalline nanotubes have been synthesized from precursor of CdS/cadmium thiolate complex at room temperature. The precursor was hydrothermally synthesized at 180 °C using thioglycolic acid (TGA) and cadmium acetate as starting materials. The transformation from the rod-like precursor of CdS/cadmium thiolate complex to CdS, CdSe and CdTe nanotubes were performed under constant stirring at room temperature in aqueous solution containing S 2-, Se 2- and Te 2-, respectively. The nanotube diameter can be controlled from 150 to 400 nm related to the dimension of templates. The XRD patterns show the cadmium chalcogenide nanotubes all corresponding to face-centered cubic structure. © 2012 Elsevier B.V. All rights reserved.

  6. Electronic structure and optical spectra of semiconducting carbon nanotubes functionalized by diazonium salts

    Science.gov (United States)

    Ramirez, Jessica; Mayo, Michael L.; Kilina, Svetlana; Tretiak, Sergei

    2013-02-01

    We report density functional (DFT) calculations on finite-length semiconducting carbon nanotubes covalently and non-covalently functionalized by aryl diazonium moieties and their chlorinated derivatives. For these systems, we investigate (i) an accuracy of different functionals and basis sets, (ii) a solvent effect, and (iii) the impact of the chemical functionalization on optical properties of nanotubes. In contrast to B3LYP, only long-range-corrected functionals, such as CAM-B3LYP and wB97XD, properly describe the ground and excited state properties of physisorbed molecules. We found that physisorbed cation insignificantly perturbs the optical spectra of nanotubes. In contrast, covalently bound complexes demonstrate strong redshifts and brightening of the lowest exciton that is optically dark in pristine nanotubes. However, the energy and oscillator strength of the lowest state are dictated by the position of the molecule on the nanotube. Thus, if controllable and selective chemical functionalization is realized, the PL of nanotubes could be improved.

  7. 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.

  8. Direct Synthesis of Polymer Nanotubes by Aqueous Dispersion Polymerization of a Cyclodextrin/Styrene Complex.

    Science.gov (United States)

    Chen, Xi; Liu, Lei; Huo, Meng; Zeng, Min; Peng, Liao; Feng, Anchao; Wang, Xiaosong; Yuan, Jinying

    2017-12-22

    A one-step synthesis of nanotubes by RAFT dispersion polymerization of cyclodextrin/styrene (CD/St) complexes directly in water is presented. The resulted amphiphilic PEG-b-PS diblock copolymers self-assemble in situ into nanoparticles with various morphologies. Spheres, worms, lamellae, and nanotubes were controllably obtained. Because of the complexation, the swelling degree of polystyrene (PS) blocks by free St is limited, resulting in limited mobility of PS chains. Consequently, kinetically trapped lamellae and nanotubes were obtained instead of spherical vesicles. During the formation of nanotubes, small vesicles first formed at the ends of the tape-like lamellae, then grew and fused into nanotubes with a limited chain rearrangement. The introduction of a host-guest interaction based on CDs enables the aqueous dispersion polymerization of water-immiscible monomers, and produces kinetically trapped nanostructures, which could be a powerful technique for nanomaterials synthesis. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Template-free synthesis of fully collapsed carbon nanotubes and graphene nanoribbons by chemical vapor deposition

    International Nuclear Information System (INIS)

    Zhang, Yong-Xing; Jia, Yong

    2015-01-01

    Highlights: • Commercial Fe 2 O 3 and Al 2 O 3 powders were chosen to prepare Fe 2 O 3 /Al 2 O 3 catalyst. • Fully collapsed carbon nanotubes and graphene nanoribbons were synthesized through the catalytic decomposition of methane at 900 °C. • The formation mechanism of the fully collapsed carbon nanotubes was revealed. - Abstract: Fe 2 O 3 /Al 2 O 3 catalyst was prepared by simply calcining the mixture of commercial Fe 2 O 3 and Al 2 O 3 powders at 1000 °C. The obtained Fe 2 O 3 /Al 2 O 3 catalyst shows high efficiency for the synthesis of fully collapsed carbon nanotubes and graphene nanoribbons through the catalytic decomposition of methane at 900 °C. The yield of the fully collapsed carbon nanotubes and graphene nanoribbons was 19.5 wt%. Field emission scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy and thermal gravimetric analysis were used to characterize the products. A tip-growth mechanism for the fully collapsed carbon nanotubes was suggested based on the SEM and TEM images of products produced at the initial stage. The break through of the catalyst particle from graphite layers resulted in the crack and then cut open of the fully collapsed carbon nanotubes, which further resulted in the formation of the graphene nanoribbons.

  10. Synthesis of boron nitride nanotubes by an oxide-assisted chemical method

    International Nuclear Information System (INIS)

    Singhal, S. K.; Srivastava, A. K.; Gupta, Anil K.; Chen, Z. G.

    2010-01-01

    We report a new method for the synthesis of boron nitride (BN) nanotubes employing a two-step process in which some oxides have found to catalyze the growth of BN nanotubes. In the first step, a precursor containing B-N-O-Fe/Mg was prepared by ball milling a mixture of B, B 2 O 3 , Fe 2 O 3 and MgO (1:7:2:1 mass ratio) in NH 3 for 3 h. BN nanotubes (diameter: 20-100 nm) were grown in the second step from this precursor by isothermal annealing at 1,350 o C in NH 3 for about 4 h. XRD, SEM and HR-TEM studies elucidated the spindle-like morphology of these nanotubes of hexagonal crystal structure. The Raman spectrum showed the peak broadening and shifts to higher frequency. The present method showed that some oxides assisted the growth of BN nanotubes. A possible reaction mechanism on the formation of BN nanotubes in the presence of these oxides is discussed.

  11. Nonlinear optical properties measurement of polypyrrole -carbon nanotubes prepared by an electrochemical polymerization method

    Directory of Open Access Journals (Sweden)

    Shahriari

    2017-02-01

    Full Text Available In this work, the optical properties dependence of Multi-Walled Carbon Nanotubes (MWNT on concentration was discussed. MWNT samples were prepared in polypyrrole by an electrochemical polymerization of monomers, in the presence of different concentrations of MWNTs, using Sodium Dodecyl-Benzen-Sulfonate (SDBS as surfactant at room temperature. The nonlinear refractive and nonlinear absorbtion indices were measured using a low power CW laser beam operated at 532 nm using z-scan method. The results show that nonlinear refractive and nonlinear absorbtion indices tend to be increased with increasing the concentration of carbon nanotubes. Optical properties of  carbone nanotubes indicate that they are good candidates for nonlinear optical devices

  12. Flame Synthesis of Single- and Multi-Walled Carbon Nanotubes and Nanofibers

    Science.gov (United States)

    VanderWal, R. L.; Ticich, Thomas M.

    2001-01-01

    Metal-catalyzed carbon nanotubes are highly sought for a diverse range of applications that include nanoelectronics, battery electrode material, catalysis, hydrogen storage media and reinforcing agents in polymer composites. These latter applications will require vast quantities of nanotubes at competitive prices to be economically feasible. Moreover, reinforcing applications may not require ultrahigh purity nanotubes. Indeed, functionalization of nanotubes to facilitate interfacial bonding within composites will naturally introduce defects into the tube walls, lessening their tensile strength. Current methods of aerosol synthesis of carbon nanotubes include laser ablation of composite targets of carbon and catalyst metal within high temperature furnaces and decomposition of a organometallics in hydrocarbons mixtures within a tube furnace. Common to each approach is the generation of particles in the presence of the reactive hydrocarbon species at elevated temperatures. In the laser-ablation approach, the situation is even more dynamic in that particles and nanotubes are borne during the transient cooling phase of the laser-induced plasma for which the temperature far exceeds that of the surrounding hot gases within the furnace process tube. A shared limitation is that more efficient methods of nanoparticle synthesis are not readily incorporated into these approaches. In contrast, combustion can quite naturally create nanomaterials such as carbon black. Flame synthesis is well known for its commercial scalability and energy efficiency. However, flames do present a complex chemical environment with steep gradients in temperature and species concentrations. Moreover, reaction times are limited within buoyant driven flows to tens of milliseconds. Therein microgravity can greatly lessen temperature and spatial gradients while allowing independent control of flame residence times. In preparation for defining the microgravity experiments, the work presented here focuses

  13. Synthesis and optical properties studies

    Directory of Open Access Journals (Sweden)

    N.A. El-Ghamaz

    2017-01-01

    Full Text Available 4-(4-Amino-1,5-dimethyl-2-phenyl-1,2-dihydro-pyrazol-3-ylideneamino-phenol (L1 and 4-(4-Amino-1,5-dimethyl-2-phenyl-1,2-dihydro-pyrazol-3-ylideneamino-benzoic acid (L2 have been synthesized by the condensation reaction of 4-aminoantipyrine (4-AAP and 4-aminophenol or 4-aminobenzoic acid in ethanolic solution and are characterized by various physico-chemical techniques. Thin films of L1 and L2 have been prepared by the conventional spin coating technique. X-ray diffraction patterns (XRD show an amorphous nature for both powder and thin films for L1 and L2 ligands. The optical absorption and refraction properties of L1 and L2 are investigated by spectrophotometric techniques at normal incidence of light in the wavelength range of 200–2500 nm. The absorption spectra show two peaks in the UV region which correspond to π → π∗ transition and a peak in UV–Vis region which may correspond to n → π∗ transition. The values of dispersion parameters Eo, Ed, εL, ε∞ and N/m* are calculated according to the single oscillator model. The presence of the OH group increases the value of ε∞ from 3.21 to 3.32 and the value of N/m* from 7.38 × 1053 to 2.08 × 1054 m−3Kg−1. The optical band transition is found to be indirect allowing fundamental energy gap values of 3.4 and 3.9 eV and onset energy gap values of 2.1 and 2.6 eV for L1 and L2, respectively.

  14. Synthesis of optimized indium phosphide/zinc sulfide core/shell nanocrystals and titanium dioxide nanotubes for quantum dot sensitized solar cells

    Science.gov (United States)

    Lee, Seungyong

    Synthesis of InP/ZnS core/shell nanocrystals and TiO 2 nanotubes and the optimization study to couple them together were explored for quantum dot sensitized solar cells. Its intrinsic nontoxicity makes the direct band gap InP/ZnS core/shell be one of the most promising semiconductor nanocrystals for optoelectric applications, with the advantage of tuning the optical absorption range in the desired solar spectrum region. Highly luminescent and monodisperse InP/ZnS nanocrystals were synthesized in a non-coordinating solvent. By varying the synthesis scheme, different size InP/ZnS nanocrystals with emission peaks ranging from 520 nm to 620 nm were grown. For the purpose of ensuring air stability, a ZnS shell was grown. The ZnS shell improves the chemical stability in terms of oxidation prevention. Transmission electron microscopy (TEM) image shows that the nanocrystals are highly crystalline and monodisperse. Free-standing TiO2 nanotubes were produced by an anodization method using ammonium fluoride. The free-standing nanotubes were formed under the condition that the chemical dissolution speed associated with fluoride concentration was faster than the speed of Ti oxidation. Highly ordered free-standing anatase form TiO2 nanotubes, which are transformed by annealing at the optimized temperature, are expected to be ideal for coupling with the prepared InP/ZnS nanocrystals. Electrophoretic deposition was carried out to couple the InP/ZnS nanocrystals with the TiO2 nanotubes. Under the adjusted applied voltage condition, the current during the electrophoretic deposition decreased continuously with time. The amount of the deposited nanocrystals was estimated by calculation and the evenly deposited nanocrystals on the TiO2 nanotubes were observed by TEM.

  15. Chirality-Controlled Synthesis and Applications of Single-Wall Carbon Nanotubes.

    Science.gov (United States)

    Liu, Bilu; Wu, Fanqi; Gui, Hui; Zheng, Ming; Zhou, Chongwu

    2017-01-24

    Preparation of chirality-defined single-wall carbon nanotubes (SWCNTs) is the top challenge in the nanotube field. In recent years, great progress has been made toward preparing single-chirality SWCNTs through both direct controlled synthesis and postsynthesis separation approaches. Accordingly, the uses of single-chirality-dominated SWCNTs for various applications have emerged as a new front in nanotube research. In this Review, we review recent progress made in the chirality-controlled synthesis of SWCNTs, including metal-catalyst-free SWCNT cloning by vapor-phase epitaxy elongation of purified single-chirality nanotube seeds, chirality-specific growth of SWCNTs on bimetallic solid alloy catalysts, chirality-controlled synthesis of SWCNTs using bottom-up synthetic strategy from carbonaceous molecular end-cap precursors, etc. Recent major progresses in postsynthesis separation of single-chirality SWCNT species, as well as methods for chirality characterization of SWCNTs, are also highlighted. Moreover, we discuss some examples where single-chirality SWCNTs have shown clear advantages over SWCNTs with broad chirality distributions. We hope this review could inspire more research on the chirality-controlled preparation of SWCNTs and equally important inspire the use of single-chirality SWCNT samples for more fundamental studies and practical applications.

  16. Synthesis of neodymium hydroxide nanotubes and nanorods by soft chemical process.

    Science.gov (United States)

    Shi, Weidong; Yu, Jiangbo; Wang, Haishui; Yang, Jianhui; Zhang, Hongjie

    2006-08-01

    A facile soft chemical approach using cetyltrimethylammonium bromide (CTAB) as template is successfully designed for synthesis of neodymium hydroxide nanotubes. These nanotubes have an average outer diameter around 20 nm, inner diameter around 2 nm, and length ranging from 100 to 120 nm, high BET surface area of 495.71 m(2) g(-1). We also find that neodymium hydroxide nanorods would be obtained when CTAB absented in reaction system. The Nd(OH)3 nanorods might act as precursors that are converted into Nd2O3 nanorods through dehydration at 550 degrees C. The nanorods could exhibit upconversion emission characteristic under excitation of 591 nm at room temperature.

  17. Synthesis of multiwalled carbon nanotube from different grades of carbon black using arc discharge method

    Energy Technology Data Exchange (ETDEWEB)

    Arora, Neha, E-mail: n4neha31@gmail.com [Department of Mechanical Engineering, Birla Institute of Technology and Science, Pilani (India); Sharma, N. N. [Department of Mechanical Engineering, Birla Institute of Technology and Science, Pilani (India); Director, School of Automobile, Mechanical & Mechatronics, Manipal University,Jaipur,India (India)

    2016-04-13

    This paper describes the synthesis of nanotube from different grades (Tread * A(non-ASTM), N134,N121,N660 and N330)of carbon black using DC arc discharge method at 40A current for 60sec. Carbon black samples of different grades were procured from industry (Aditya Birla Science and Technology Limited, India). Scanning Electron Micrographs (SEM) of the deposited carbon nanostructures suggests that MWCNTs are formed at 40A and for a minimal exposure time of 60sec.The result formed indicates the N330 grade of carbon black gets converted to MWCNTs (Multiwall Carbon nanotube) as compared to other grades.

  18. Synthesis and non-covalent functionalization of carbon nanotubes rings: new nanomaterials with lectin affinity

    International Nuclear Information System (INIS)

    Assali, Mohyeddin; Leal, Manuel Pernía; Khiar, Noureddine; Fernández, Inmaculada

    2013-01-01

    We present a mild and practical carbon nanotubes rings (CNRs) synthesis from non-covalent functionalized and water-soluble linear single-wall carbon nanotubes. The hemi-micellar–supramolecular self-organization of lactose-based glycolipid 1 on the ring surface, followed by photo-polymerization of the diacetylenic function triggered by UV light afforded the first water-soluble and biocompatible CNRs. The obtained donut-like nanoconstructs expose a high density of lactose moieties on their surface, and are able to engage specific interactions with Arachis hypogea lectin similar to glycoconjugates on the cell membrane. (paper)

  19. Optical spectroscopy of iodine-doped single-wall carbon nanotubes of different diameter

    International Nuclear Information System (INIS)

    Tonkikh, Alexander A.; Obraztsova, Elena D.; Pozharov, Anatolii S.; Obraztsova, Ekaterina A.; Belkin, Alexey V.

    2012-01-01

    Single-wall carbon nanotubes with polyiodide chains inside are interesting from two points of view. According to predictions, first, the iodine structure type inside the nanotube is determined by the nanotube geometry. Second, after iodination all nanotubes become metallic. In this work, we made an attempt to check both predictions. To study the diameter-dependent properties we have taken for a gas-phase iodination the pristine single-wall carbon nanotubes grown by three different techniques providing a different average diameter: a chemical vapor deposition with a Co/Mo catalyst (CoMoCat) with a diameter range (0.6-1.3) nm, a high-pressure CO decomposition (HiPCO) - a diameter range (0.8-1.5) nm, and an aerosol technique with Fe catalyst - a diameter range (1.3-2.0) nm. The Raman spectra have shown a complication of the polyiodide chain structure while the nanotube diameter increased. The optical spectroscopy data (a suppression of E 11 band in the UV-Vis-NIR absorption spectrum) have confirmed the theoretical prediction about transformation of all nanotubes into metallic phase after doping. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  20. Synthesis of polyaniline nanotubes through UV light catalytic method

    Directory of Open Access Journals (Sweden)

    Chuanyu Sun

    2015-03-01

    Full Text Available In this study, nitrocellulose (NC fiber blanket prepared by electrostatic spinning method has been used as a template, and copper nitrate (Cu(NO32 as an oxidant to synthesise polyaniline nanotubes doped with heteropolyacid (H4SiW12O40, SiW12 using UV light catalytic method. Infrared spectroscopy (IR, X-ray powder diffraction (XRD, scanning electron microscopy (SEM and transmission electron microscopy (TEM technologies were applied to characterize the prepared samples of polyaniline nanotubes. The results show that the external diameter of the tube is about 200 nm, and the internal diameter about 170 nm. We also give a reasonable speculation and explanation about the formation mechanism of the nanotubes.

  1. Carbon nanotubes: properties, synthesis, purification, and medical applications

    Science.gov (United States)

    2014-01-01

    Current discoveries of different forms of carbon nanostructures have motivated research on their applications in various fields. They hold promise for applications in medicine, gene, and drug delivery areas. Many different production methods for carbon nanotubes (CNTs) have been introduced; functionalization, filling, doping, and chemical modification have been achieved, and characterization, separation, and manipulation of individual CNTs are now possible. Parameters such as structure, surface area, surface charge, size distribution, surface chemistry, and agglomeration state as well as purity of the samples have considerable impact on the reactivity of carbon nanotubes. Otherwise, the strength and flexibility of carbon nanotubes make them of potential use in controlling other nanoscale structures, which suggests they will have a significant role in nanotechnology engineering. PMID:25170330

  2. Carbon nanotubes: properties, synthesis, purification, and medical applications

    Science.gov (United States)

    Eatemadi, Ali; Daraee, Hadis; Karimkhanloo, Hamzeh; Kouhi, Mohammad; Zarghami, Nosratollah; Akbarzadeh, Abolfazl; Abasi, Mozhgan; Hanifehpour, Younes; Joo, Sang Woo

    2014-08-01

    Current discoveries of different forms of carbon nanostructures have motivated research on their applications in various fields. They hold promise for applications in medicine, gene, and drug delivery areas. Many different production methods for carbon nanotubes (CNTs) have been introduced; functionalization, filling, doping, and chemical modification have been achieved, and characterization, separation, and manipulation of individual CNTs are now possible. Parameters such as structure, surface area, surface charge, size distribution, surface chemistry, and agglomeration state as well as purity of the samples have considerable impact on the reactivity of carbon nanotubes. Otherwise, the strength and flexibility of carbon nanotubes make them of potential use in controlling other nanoscale structures, which suggests they will have a significant role in nanotechnology engineering.

  3. Synthesis and Characterization Carbon Nanotubes Doped Carbon Aerogels

    Science.gov (United States)

    Xu, Yuelong; Yan, Meifang; Liu, Zhenfa

    2017-12-01

    Polycondensation of phloroglucinol, resorcinol and formaldehyde with carbon nanotube (CNT) as the additives, using sodium carbonate as the catalyst, leads to the formation of CNT - doped carbon aerogels. The structure of carbon aerogels (CAs) with carbon nanotubes (CNTs) were characterized by X-ray diffraction and scanning electron microscopy. The specific surface area, pore size distribution and pore volume were measured by surface area analyzer. The results show that when the optimum doping dosage is 5%, the specific surface area of CNT - doped carbon aerogel is up to 665 m2 g-1 and exhibit plentiful mesoporous.

  4. Synthesis of copper sulfide nanotube in the hydrogel system

    International Nuclear Information System (INIS)

    Tan Changhui; Zhu Yulan; Lu Ran; Xue Pengchong; Bao Chunyan; Liu Xinli; Fei Zhuping; Zhao Yingying

    2005-01-01

    This paper presents a novel method for the preparation of copper sulfide (CuS) nanotubes using hydrogel based on N-lauroylalanine as template under mild condition. The resulting samples are examined by transmission electron microscopy (TEM) FT-IR spectroscopy, X-ray powder diffraction (XRD), UV-vis absorption spectroscopy. It is found that the intermolecular hydrogen bonds play an important role on the formation of the hydrogel and the Cu 2+ coordination gel. The formation process of CuS nanotube is also discussed

  5. The third-order nonlinear optical susceptibility of C{sub 60}-derived nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Xiangang, Wan [Nanjing Univ. (China). National Lab. of Solid State Microstructures; [Center for Advanced Studies in Science and Technology of Microstructures, Nanjing (China); Jinming, Dong [Nanjing Univ. (China). National Lab. of Solid State Microstructures; [Center for Advanced Studies in Science and Technology of Microstructures, Nanjing (China); Jie, Jiang [Nanjing Univ., JS (China). Dept. of Physics; Xing, D Y [Nanjing Univ., JS (China). Dept. of Physics

    1997-02-01

    Using the extended Su-Schrieffer-Heeger (SSH) model and the sum-over-state (SOS) method, we have calculated the third-order nonlinear polarizability {gamma} and its dispersion spectra for C{sub 60}-derived nanotubes, which is one of the narrowest tubes. Our numerical calculations indicate that both symmetry and size of the nanotubes have great effect on the third-order nonlinear polarizability {gamma} spectra. We find that with increasing size, both static {gamma} values and dynamical response peak values increase. When the atom number of the C{sub 60}-derived nanotubes is 140, the static {gamma} value is about 65 times larger than that of C{sub 60}, and the highest peak value of {gamma} (at 3{omega} = 3.52 eV) is about three orders larger than that of C{sub 60}. So, C{sub 60}-derived nanotubes may become a kind of good nonlinear optical materials. (orig.)

  6. Synthesis and Evaluation of Porous Semiconductor Hexaniobate Nanotubes for Photolysis of Organic Dyes in Wastewater

    Directory of Open Access Journals (Sweden)

    Maryam Zarei-Chaleshtori

    2014-10-01

    Full Text Available We present the chemical synthesis of hexaniobate nanotubes using two routes, (1 starting material K4Nb6O17 and (2 parent material of H4Nb6O17 via ion exchange. The as-synthesized materials were exfoliated by adjusting the pH to 9–10 using tetra-n-butylammonioum hydroxide (TBA+OH−, leading to a formation of hexaniobate nanotubes. In order to understand morphology a full characterization was conducted using SEM, HRTEM, BET and powder-XRD. The photocatalytic activity was evaluated using photolysis method using Bromocresol Green (BG and Methyl Orange (MO as model contaminants. Results indicate a nanotube porous oxide with large porous and surface area; the photocatalytic activity is about 95% efficient when comparing with commercial TiO2.

  7. Carbon nanotube synthesis from propane decomposition on a pre ...

    Indian Academy of Sciences (India)

    Growth of carbon nanotubes (CNTs) was performed by atmospheric pressure chemical vapour deposition (APCVD) of propane on Si(111) with a pre-treated Ni overlayer acting as a catalyst. Prior to the growth of CNTs, a thin film of Ni was deposited on Si(111) substrate by evaporation and heat treated at 900°C. The growth ...

  8. Application of aromatization catalyst in synthesis of carbon nanotubes

    Indian Academy of Sciences (India)

    In a typical chemical vapour deposition (CVD) process for synthesizing carbon nanotubes (CNTs), it was found that the aromatization catalysts could promote effectively the formation of CNT. The essence of this phenomenon was attributed to the fact that the aromatization catalyst can accelerate the ...

  9. Improved synthesis of carbon nanotubes with junctions and of single ...

    Indian Academy of Sciences (India)

    Unknown

    Abstract. Pyrolysis of thiophene over nickel nanoparticles dispersed on silica is shown to yield Y- junction carbon nanotubes with smaller diameters than those obtained by the pyrolysis of organometallic- thiophene mixtures. In the presence of water vapour, the pyrolysis of organometallic-hydrocarbon mixtures.

  10. Synthesis of single walled carbon nanotubes by dual laser vaporization

    CSIR Research Space (South Africa)

    Moodley, MK et al.

    2006-02-27

    Full Text Available Single-walled carbon nanotubes were synthesised by the laser vaporisation of graphite composite targets in a tube furnace. Two pulsed Nd:YAG lasers operating at fundamental (1 064 nm) and 2nd harmonic (532 nm) were combined, focused and evaporated...

  11. Synthesis of Nitrogen-doped Carbon Nanotubes with Layered ...

    African Journals Online (AJOL)

    NICO

    Nitrogen-doped carbon nanotubes (CNx) were synthesized by the catalytic chemical vapour deposition ... dispersed metal nanoparticles over oxide matrices can be obtained ..... 18 S.Y. Kim, J. Lee, C.W. Na, J. Park, K. Seo and B. Kim, Chem.

  12. Synthesis of single walled carbon nanotubes by dual laser vaporization

    CSIR Research Space (South Africa)

    Moodley, MK

    2006-07-01

    Full Text Available Single walled carbon nanotubes were synthesized by the laser vaporization of graphite composite targets in a tube furnace. Two pulsed Nd:Yag lasers operating at fundamental (1064 nm) and 2 nd harmonic (532 nm) were combined, focused and evaporated...

  13. The Synthesis of Nitrogen-Doped Multiwalled Carbon Nanotubes ...

    African Journals Online (AJOL)

    ACVDmethod was used to prepare high-quality nitrogen-doped multiwalled carbon nanotubes (N-MWCNTs) using acetonitrile as the nitrogen and carbon source and acetylene as a carbon source over an Fe-Co/CaCO3 catalyst in the temperature range 700–850 °C. This represents a continuation of earlier work in which ...

  14. Sol-gel synthesis of Bi3.25La0.75Ti3O12 nanotubes

    International Nuclear Information System (INIS)

    Wang Wen; Ke Hua; Rao Jiancun; Feng Jinbiao; Feng Ming; Jia Dechang; Zhou Yu

    2011-01-01

    Research highlights: → One-dimensional (1D) ferroelectrics have been successfully synthesized. The sol-gel template synthesis is a versatile and inexpensive technique for producing nanostructures, and particularly facilitates the fabrication of complex oxide nanotubes or nanowires. Compared with the synthesis of the general nanotubes such as carbon nanotubes with simple crystal structure, the synthesis of ferroelectric compound is difficult due to the multielement and the complex crystal structures of these ferroelectrics. Herein, we report the synthesis of one-dimensional BLT nanotubes on anodic alumina (AAO) templates by immersing a template membrane in sol without polymeric additive. - Abstract: Ferroelectric Bi 3.25 La 0.75 Ti 3 O 12 (BLT) nanotubes were synthesized by sol-gel technique using nanochannel porous anodic aluminum oxide (AAO) templates, and were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and high resolution transmission electron microscopy (HRTEM). BLT nanotubes with diameter of around 240 nm and the wall thickness of about 25 nm exhibited a single orthorhombic perovskite structure and highly preferential crystal growth along the [1 1 7] orientation, which have smooth wall morphologies and well-defined diameters corresponding to the diameter of the applied template. The formation mechanism of BLT nanotubes was discussed.

  15. synthesis and optical characterization of acid-doped polyaniline thin

    African Journals Online (AJOL)

    HOD

    SYNTHESIS AND OPTICAL CHARACTERIZATION OF ACID-DOPED. POLYANILINE THIN .... MATERIALS AND METHODS .... Characterization of Se Doped Polyaniline”,Current. Applied ... with Silver Nanoparticles”, Advances in Materials.

  16. Synthesis of Carbon Nanotubes in Thermal Plasma Reactor at Atmospheric Pressure

    Directory of Open Access Journals (Sweden)

    Lukasz Szymanski

    2017-02-01

    Full Text Available In this paper, a novel approach to the synthesis of the carbon nanotubes (CNTs in reactors operating at atmospheric pressure is presented. Based on the literature and our own research results, the most effective methods of CNT synthesis are investigated. Then, careful selection of reagents for the synthesis process is shown. Thanks to the performed calculations, an optimum composition of gases and the temperature for successful CNT synthesis in the CVD (chemical vapor deposition process can be chosen. The results, having practical significance, may lead to an improvement of nanomaterials synthesis technology. The study can be used to produce CNTs for electrical and electronic equipment (i.e., supercapacitors or cooling radiators. There is also a possibility of using them in medicine for cancer diagnostics and therapy.

  17. Synthesis of optical holograms of rotating objects

    International Nuclear Information System (INIS)

    Bogdanova, T.V.; Titar', V.P.; Tomchuk, E.Ya.

    1998-01-01

    A method of synthesis of rotating objects is analyzed and its advantages over the previously known methods and restrictions caused by the nonlinear character of motion of objects being studied are determined. Numerical simulation is used to study properties of synthesized holograms and the images reconstructed with their help. The resolving power of synthesized holograms is determined. The pulsed response of the system used for the synthesis of rotating objects is studied and its isoplanar sections are determined. It is shown that in the optical range, in contrast to the radio-frequency range, one can synthesize holograms and reconstruct visual images not only of rotating objects, but of vibrating objects as well. For small angles of object rotation (0.0025 rad), an image with a high resolution power (0.0004 m) can be obtained

  18. Control of Pre-treatment for Carbon Nanotube Synthesis Using Proton Ion Beam Irradiation

    International Nuclear Information System (INIS)

    Kim, Y. H.; Kim, D. W.; Lee, S. M.; Kim, W. J.

    2008-04-01

    The carbon nanotubes are the next generation material in fuel storage system, the gas sensor, the life science sensor or the nano-size transistor, the stiffener and the heat dissipation field. For use at appropriate position in various field, it must be developed that control technique makes carbon nanotubes with high performance synthesized at appropriate location. The density of the carbon nanotube is 1 - 2g/cm3 with aluminum (2 - 3g/cm3) to be light, the elastic modulus is the level where as many of as 30 - 50 times of iron's elastic modulus and thermal conductivity is similar to the diamond, electric conductivity is high as well above the metal. Generally, many researchers have tried to synthesize the carbon nanotubes of mm length unit using the hydrogen and porous substrate, which play a role of more activating the catalyst. The proton beam which consist of H+ was able to directly inject the hydrogen into target materials such as Ni, Co, Fe as well as transfer high activation energy to them. so we were able to carry out feasibility of controlling the porosity of thin film and substrate to synthesize carbon nanotubes. The pre-treatment method of existing which is used generally heat treatment and the ammonia controls has generated island of catalyst which has increased the surface to react the hydrocarbon. However, pre-treatment method of existing caused the random nuclear creation so it was hard to control the island size of catalyst. It was not enough to understand the porous effect against synthesis of carbon nanotubes deduced from altering various substrates. In this report, it is possible investigate how hydrogen and the porous effect influence on growth of carbon nanotubes through controlling the nuclear creation of catalysts directly and the porosity of them using proton beam

  19. Synthesis and photocatalytic properties of Sn-doped TiO{sub 2} nanotube arrays

    Energy Technology Data Exchange (ETDEWEB)

    Tu Yafang; Huang Shengyou [Department of Physics, Wuhan University, Wuhan 430072 (China); Sang Jianping, E-mail: jpsang@acc-lab.whu.edu.c [Department of Physics, Wuhan University, Wuhan 430072 (China); Department of Physics, Jianghan University, Wuhan 430056 (China); Zou Xianwu [Department of Physics, Wuhan University, Wuhan 430072 (China)

    2009-08-12

    TiO{sub 2} nanotube arrays doped by Sn up to 12 at% have been prepared using template-based liquid phase deposition method. Their morphologies, structures and optical properties have been investigated by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, UV-vis absorption spectroscopy and photoluminescence spectroscopy. The photocatalytic properties of the samples were evaluated with the degradation of methylene blue under UV irradiation. The result shows that doping an appropriate amount of Sn can effectively improve the photocatalytic activity of TiO{sub 2} nanotube arrays, and the optimum dopant amount is found to be 5.6 at% in our experiments.

  20. Length-dependent optical properties of single-walled carbon nanotube samples

    International Nuclear Information System (INIS)

    Naumov, Anton V.; Tsyboulski, Dmitri A.; Bachilo, Sergei M.; Weisman, R. Bruce

    2013-01-01

    Highlights: ► Length-independent absorption per atom in single-walled carbon nanotubes. ► Reduced fluorescence quantum yield for short nanotubes. ► Exciton quenching at nanotube ends, sidewall defects probably limits quantum yield. - Abstract: Contradictory findings have been reported on the length dependence of optical absorption cross sections and fluorescence quantum yields in single-walled carbon nanotubes (SWCNTs). To clarify these points, studies have been made on bulk SWCNT dispersions subjected to length fractionation by electrophoretic separation or by ultrasonication-induced scission. Fractions ranged from ca. 120 to 760 nm in mean length. Samples prepared by shear-assisted dispersion were subsequently shortened by ultrasonic processing. After accounting for processing-induced changes in the surfactant absorption background, SWCNT absorption was found constant within ±11% as average nanotube length changed by a factor of 3.8. This indicates that the absorption cross-section per carbon atom is not length dependent. By contrast, in length fractions prepared by both methods, the bulk fluorescence efficiency or average quantum yield increased with SWCNT average length and approached an apparent asymptotic limit near 1 μm. This result is interpreted as reflecting the combined contributions of exciton quenching by sidewall defects and by the ends of shorter nanotubes

  1. Proton radiation effects on the optical properties of vertically aligned carbon nanotubes

    Science.gov (United States)

    Kuhnhenn, J.; Khavrus, V.; Leonhardt, A.; Eversheim, D.; Noll, C.; Hinderlich, S.; Dahl, A.

    2017-11-01

    This paper discusses proton-induced radiation effects in vertically aligned carbon nanotubes (VA-CNT). VACNTs exhibit extremely low optical reflectivity which makes them interesting candidates for use in spacecraft stray light suppression. Investigating their behavior in space environment is a precondition for the implementation on a satellite.

  2. Electronic and optical properties of finite carbon nanotubes in an electric field

    International Nuclear Information System (INIS)

    Chen, R B; Lee, C H; Chang, C P; Lin, M F

    2007-01-01

    The effects, caused by the geometric structure and an electric field (E), on the electronic and optical properties of quasi-zero-dimensional finite carbon nanotubes are explored by employing the tight-binding model coupled with curvature effects. Electronic properties (state energies, symmetry of electronic states, energy spacing and state degeneracy) are significantly affected by the magnitude and the direction of the electric field and the geometric structure (radius, length and chirality). The electric field, by lowering the symmetry of finite carbon nanotubes, modifies the electronic properties. Thus, the optical excitation spectra, excited by electric polarization parallel to the nanotube axis, exhibit rich delta-function-like peaks, which reveal the characteristics of the electronic properties. Therefore it follows that geometric structure and E influence the low-energy absorption spectra, i.e. the change of frequency of the first peak, the alternation of the peak height and the production of the new peaks. There are more absorption peaks when E is oriented closer to the cross-section plane. Moreover, the very complicated optical absorption spectra are characteristic for the individual chiral carbon nanotube due to its specific geometric structure. Above all, the predicted absorption spectra and the associated electronic properties could be verified by optical measurements

  3. The effect of alkaline doped catalysts on the CVD synthesis of carbon nanotubes

    DEFF Research Database (Denmark)

    Nemeth, Krisztian; Nemeth, Zoltan; Fejes, Dora

    2011-01-01

    The aim of this work was to develop new doped catalysts for chemical vapour deposition (CVD) synthesis in order to increase the quantity and quality of carbon nanotubes (CNTs). Doping compounds such as CsBr, CsCl, KBr and KCl were used to reach higher carbon deposit and carbon yield. The amount o...... of the dopant alkali compounds varied from 1 to 5%. As prepared CNTs were characterized by transmission electron microscopy (TEM), X‐ray diffraction (XRD) and Raman microscopy. Results revealed that both carbon yield and deposit could be increased over doped catalysts.......The aim of this work was to develop new doped catalysts for chemical vapour deposition (CVD) synthesis in order to increase the quantity and quality of carbon nanotubes (CNTs). Doping compounds such as CsBr, CsCl, KBr and KCl were used to reach higher carbon deposit and carbon yield. The amount...

  4. Macrokinetics of carbon nanotubes synthesis by the chemical vapor deposition method

    Science.gov (United States)

    Rukhov, Artem; Dyachkova, Tatyana; Tugolukov, Evgeny; Besperstova, Galina

    2017-11-01

    A new approach to studying and developing basic processes which take place on the surface of a metal catalyst during the thermal decomposition of carbonaceous substances in the carbon nanotubes synthesis by the chemical vapor deposition method was proposed. In addition, an analysis was made of the interrelationships between these thermal, diffusion, hydrodynamic and other synthesis processes. A strong effect of the catalyst regeneration stage on the stage of nanotube formation has been shown. Based on the developed approach, a mathematical model was elaborated. Comparison of the calculation and the experiment carried out with the NiO-MgO catalyst at propane flow rate of 50 mL/min (standard conditions) and ethanol flow rate 0.3 mL/min (liq.) has revealed a discrepancy of less than 10%.

  5. Synthesis of single and multi-shell carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Lambert, J M [Groupe de Dynamique des Phases Condensees, Univ. de Montpellier 2, 34 Montpellier (France); Ajayan, P M [Lab. de Physique des Solides, Univ. Paris-Sud, 91 Orsay (France); Bernier, P [Groupe de Dynamique des Phases Condensees, Univ. de Montpellier 2, 34 Montpellier (France)

    1995-03-15

    We report here interesting growth morphologies produced during the electric arc-discharge between a graphite cathode and different composite metal-graphite anodes: when the metal is pure cobalt powder, we obtain, under certain conditions of pressure and cobalt content in the electrode, many single-shell carbon nanotubes of 1-2 nm diameter which appear in the soot, webs, threads (in the reactor chamber) and also on a collaret that forms around the conventional deposit containing multi-shell nanotubes. When the metal is pure manganese powder, we obtain multi-layer hollow carbon fibers in the soot similar to the carbon fibers grown by catalytic chemical vapor deposition. Furthermore, many fibers have a good portion of the length filled with metal. We present here high-resolution transmission electron microscopy images of these structures. (orig.)

  6. Synthesis of bulk quantity BN nanotubes with uniform morphology

    International Nuclear Information System (INIS)

    Wen, G.; Zhang, T.; Huang, X.X.; Zhong, B.; Zhang, X.D.; Yu, H.M.

    2010-01-01

    Bulk quantity hexagonal BN nanotubes (h-BNNTs) with uniform morphology were synthesized via an improved ball-milling and annealing method. The sample was characterized by X-ray photoelectron spectrometry, electron energy loss spectroscopy, X-ray diffraction, scanning electron microscopy, conventional transmission electron microscopy (TEM) and high-resolution TEM. The results show that the fabricated BNNTs have a uniform diameter ranging from 80 to 100 nm and a length of about 50-60 μm.

  7. Fabrication and characterization of nanocomposites reinforced by carbon nanotubes - (1) synthesis of carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Hseuh Hsiangming; Tai Nyanhwa; Perng Tongping [Dept. of Material Science, National Tsing-Hwa Univ., TW (China); Chyou Sander [Taiwan Power Research Inst., Taiwan Power Co., Taipei (China)

    2003-07-01

    Multi-walled carbon nanotubes (MWCNTs) produced by floating catalyst method were used for reinforcing material in polymeric nanocomposites. Five different kinds of carbon sources (benzene, toluene, xylene, cyclo-hexane, n-hexane) were used as precursors in the thermal chemical vapor deposition process. The products were collected and examined by Raman, HRTEM, and FESEM. The differences in microstructure and morphologies among these products are analyzed and discussed. (orig.)

  8. Tuning the optical properties of carbon nanotube solutions using amphiphilic self-assembly

    Science.gov (United States)

    Arnold, Michael S.; Stupp, Samuel I.; Hersam, Mark C.

    2003-07-01

    Recently it has been shown that aqueous solutions of sodium dodecyl sulfate (SDS) encapsulated and polymer wrapped single-walled carbon nanotubes (SWNTs) fluoresce in the near infrared (NIR) in the regime of the E11 van Hove transitions for semiconducting SWNTs. For bundled SWNTs, fluorescence is observed to be quenched along with a shift and broadening of the absorbance spectrum. Here, we study two other commercially available surfactants, BRIJ-97 and Triton-X-100, by analysis of carbon nanotube fluorescence and absorptivity in the NIR. It is found that changing the surfactant alters the corresponding optical properties of the solubilized carbon nanotubes. The NIR absorbance spectra of BRIJ-97 and Triton-X-100 carbon nanotube solutions are also compared with the absorbance spectrum of NaCl destabilized SDS-SWNT solutions. By controlling the amount of NaCl added to an aqueous solution of SDS-SWNTs, the optical absorbance spectrum can be made to match that of BRIJ-97 and Triton-X-100 solutions. Lastly, a correlation is drawn between the amount of shift in the absorbance spectrum and the fluorescence intensity, independent of surfactant used. This shift and decrease in fluorescence intensity may be due to carbon nanotube bundling.

  9. Synthesis and characterization of covalent diphenylalanine nanotube-folic acid conjugates

    DEFF Research Database (Denmark)

    León, John Jairo Castillo; Rindzevicius, Tomas; Wu, Kaiyu

    2014-01-01

    Herein, we describe the synthesis and characterization of a covalent nanoscale assembly formed between diphenylalanine micro/nanotubes (PNT) and folic acid (FA). The conjugate was obtained via chemical functionalization through coupling of amine groups of PNTs and carboxylic groups of FA. The sur...... for applications in the detection and diagnosis of cancer or tropical diseases such as leishmaniasis and as a carrier nanosystem delivering drugs to malignant tumors that overexpress folate receptors....

  10. Synthesis and characterization of conducting polyaniline 5-sulfosalicylate nanotubes

    International Nuclear Information System (INIS)

    Janosevic, Aleksandra; Ciric-Marjanovic, Gordana; Marjanovic, Budimir; Holler, Petr; Trchova, Miroslava; Stejskal, Jaroslav

    2008-01-01

    Conducting polyaniline 5-sulfosalicylate nanotubes and nanorods were synthesized by the template-free oxidative polymerization of aniline in aqueous solution of 5-sulfosalicylic acid, using ammonium peroxydisulfate as an oxidant. The effect of the molar ratio of 5-sulfosalicylic acid to aniline on the molecular structure, molecular weight distribution, morphology, and conductivity of polyaniline 5-sulfosalicylate was investigated. The nanotubes, which have a typical outer diameter of 100-250 nm, with an inner diameter of 10-60 nm, and a length extending from 0.4 to 1.5 μm, and the nanorods, with a diameter of 80-110 nm and a length of 0.5-0.7 μm, were observed by scanning and transmission electron microscopies. The presence of branched structures and phenazine units besides the ordinary polyaniline structural features was revealed by infrared and Raman spectroscopies. The stacking of low-molecular-weight substituted phenazines appears to play a major role in the formation of polyaniline nanorods. The precipitation-dissolution of oligoaniline templates as a key element in the formation of polyaniline nanotubes is proposed to explain the crucial influence of the initial pH of the reaction mixture and its decrease during the course of polymerization

  11. Synthesis and characterization of conducting polyaniline 5-sulfosalicylate nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Janosevic, Aleksandra; Ciric-Marjanovic, Gordana [Faculty of Physical Chemistry, University of Belgrade, Studentski Trg 12-16, 11001 Belgrade (Serbia); Marjanovic, Budimir [Centrohem, Vuka Karadzica bb, 22300 Stara Pazova (Serbia); Holler, Petr; Trchova, Miroslava; Stejskal, Jaroslav [Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, 162 06 Prague 6 (Czech Republic)], E-mail: gordana@ffh.bg.ac.yu

    2008-04-02

    Conducting polyaniline 5-sulfosalicylate nanotubes and nanorods were synthesized by the template-free oxidative polymerization of aniline in aqueous solution of 5-sulfosalicylic acid, using ammonium peroxydisulfate as an oxidant. The effect of the molar ratio of 5-sulfosalicylic acid to aniline on the molecular structure, molecular weight distribution, morphology, and conductivity of polyaniline 5-sulfosalicylate was investigated. The nanotubes, which have a typical outer diameter of 100-250 nm, with an inner diameter of 10-60 nm, and a length extending from 0.4 to 1.5 {mu}m, and the nanorods, with a diameter of 80-110 nm and a length of 0.5-0.7 {mu}m, were observed by scanning and transmission electron microscopies. The presence of branched structures and phenazine units besides the ordinary polyaniline structural features was revealed by infrared and Raman spectroscopies. The stacking of low-molecular-weight substituted phenazines appears to play a major role in the formation of polyaniline nanorods. The precipitation-dissolution of oligoaniline templates as a key element in the formation of polyaniline nanotubes is proposed to explain the crucial influence of the initial pH of the reaction mixture and its decrease during the course of polymerization.

  12. Synthesis of Fe2O3/TiO2 nanorod-nanotube arrays by filling TiO2 nanotubes with Fe

    International Nuclear Information System (INIS)

    Mohapatra, Susanta K; Banerjee, Subarna; Misra, Mano

    2008-01-01

    Synthesis of hematite (α-Fe 2 O 3 ) nanostructures on a titania (TiO 2 ) nanotubular template is carried out using a pulsed electrodeposition technique. The TiO 2 nanotubes are prepared by the sonoelectrochemical anodization method and are filled with iron (Fe) by pulsed electrodeposition. The Fe/TiO 2 composite is then annealed in an O 2 atmosphere to convert it to Fe 2 O 3 /TiO 2 nanorod-nanotube arrays. The length of the Fe 2 O 3 inside the TiO 2 nanotubes can be tuned from 50 to 550 nm by changing the deposition time. The composite material is characterized by scanning electron microscopy, transmission electron microscopy and diffuse reflectance ultraviolet-visible studies to confirm the formation of one-dimensional Fe 2 O 3 /TiO 2 nanorod-nanotube arrays. The present approach can be used for designing variable one-dimensional metal oxide heterostructures

  13. Acoustical characterisation of carbon nanotube-loaded polydimethylsiloxane used for optical ultrasound generation

    OpenAIRE

    Alles, E. J.; Heo, J.; Noimark, S.; Colchester, R.; Parkin, I.; Baac, H. W.; Desjardins, A.

    2017-01-01

    An optical ultrasound generator was used to perform broadband (2-35 MHz) acoustical characterisation measurements of a nanocomposite comprising carbon nanotubes (CNT) and polydimethylsiloxane (PDMS), a composite that is commonly used as optical ultrasound generator. Samples consisting of either pure PDMS or CNT-loaded PDMS were characterised to determine the influence of CNTs on the speed of sound and power-law acoustic attenuation parameters. A small weight fraction (

  14. Optical absorption of charged excitons in semiconducting carbon nanotubes

    DEFF Research Database (Denmark)

    Rønnow, Troels Frimodt; Pedersen, Thomas Garm; Cornean, Horia

    2012-01-01

    In this article we examine the absorption coefficient of charged excitons in carbon nanotubes. We investigate the temperature and damping dependence of the absorption spectra. We show that the trion peak in the spectrum is asymmetric for temperatures greater than approximately 1 K whereas...

  15. Carbon nanotubes on carbon fibers: Synthesis, structures and properties

    Science.gov (United States)

    Zhang, Qiuhong

    The interface between carbon fibers (CFs) and the resin matrix in traditional high performance composites is characterized by a large discontinuity in mechanical, electrical, and thermal properties which can cause inefficient energy transfer. Due to the exceptional properties of carbon nanotubes (CNTs), their growth at the surface of carbon fibers is a promising approach to controlling interfacial interactions and achieving the enhanced bulk properties. However, the reactive conditions used to grow carbon nanotubes also have the potential to introduce defects that can degrade the mechanical properties of the carbon fiber (CF) substrate. In this study, using thermal chemical vapor deposition (CVD) method, high density multi-wall carbon nanotubes have been successfully synthesized directly on PAN-based CF surface without significantly compromising tensile properties. The influence of CVD growth conditions on the single CF tensile properties and carbon nanotube (CNT) morphology was investigated. The experimental results revealed that under high temperature growth conditions, the tensile strength of CF was greatly decreased at the beginning of CNT growth process with the largest decrease observed for sized CFs. However, the tensile strength of unsized CFs with CNT was approximately the same as the initial CF at lower growth temperature. The interfacial shear strength of CNT coated CF (CNT/CF) in epoxy was studied by means of the single-fiber fragmentation test. Results of the test indicate an improvement in interfacial shear strength with the addition of a CNT coating. This improvement can most likely be attributed to an increase in the interphase yield strength as well as an improvement in interfacial adhesion due to the presence of the nanotubes. CNT/CF also offers promise as stress and strain sensors in CF reinforced composite materials. This study investigates fundamental mechanical and electrical properties of CNT/CF using nanoindentation method by designed

  16. Optical and electrical characterizations of nanocomposite film of titania adsorbed onto oxidized multiwalled carbon nanotubes

    International Nuclear Information System (INIS)

    Feng Wei; Feng Yiyu; Wu Zigang; Fujii, Akihiko; Ozaki, Masanori; Yoshino, Katsumi

    2005-01-01

    Composite film containing titania electrostatically linked to oxidized multiwalled carbon nanotubes (TiO 2 -s-MWNTs) was prepared from a suspension of TiO 2 nanoparticles in soluble carbon nanotubes. The structure of the film was analysed principally by Fourier transform infrared spectroscopy, scanning electron micrography and x-ray diffraction. The optical and electrical characterizations of the film were investigated by UV-vis spectrum, photoluminescence and photoconductivity. The enhancement of photocurrent in the TiO 2 -s-MWNT film is discussed by taking the photoinduced charge transfer between the MWNT and TiO 2 into consideration

  17. Progammed synthesis of magnetic mesoporous silica coated carbon nanotubes for organic pollutant adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Tong, Yue; Zhang, Min, E-mail: congmingyang123@163.com; Xia, Peixiong; Wang, Linlin; Zheng, Jing; Li, Weizhen; Xu, Jingli, E-mail: xujingli@sues.edu.cn

    2016-05-15

    Magnetic mesoporous silica coated carbon nanotubes were produced from hydrophilic monodisperse magnetic nanoparticles decorated carbon nanotubes using well controlled programmed synthesis method and were characterized by TEM, XRD, FTIR, TGA, N{sub 2} adsorption–desorption and VSM. The well-designed mesoporous magnetic nanotubes had a large specific area, a highly open mesoporous structure and high magnetization. Firstly, SiO{sub 2}-coated maghemite/CNTs nanoparticles (CNTs/Fe{sub 3}O{sub 4}@SiO{sub 2} composites) were synthesized by the combination of high temperature decomposition process and an sol–gel method, in which the iron acetylacetonate as well as TEOS acted as the precursor for maghemite and SiO{sub 2}, respectively. The CNTs/Fe{sub 3}O{sub 4}@SiO{sub 2} composites revealed a core–shell structure, Then, CNTs/Fe{sub 3}O{sub 4}@mSiO{sub 2} was obtained by extracting cetyltrimethylammonium bromide (CTAB) via an ion-exchange procedure. The resulting composites show not only a magnetic response to an externally applied magnetic field, but also can be a good adsorbent for the organic pollutant in the ambient temperature. - Graphical abstract: Magnetic mesoporous silica coated carbon nanotubes were produced from hydrophilic monodisperse magnetic nanoparticles decorated carbon nanotubes using well controlled programmed synthesis, which can be a good adsorbent for the organic pollutant in the ambient temperature. - Highlights: • The surface of CNTs/Fe{sub 3}O{sub 4} is hydrophilic, which facilitates the silica coating. • The CNTs/Fe{sub 3}O{sub 4}@mSiO{sub 2} was synthesized by a facile method. • The CNTs/Fe{sub 3}O{sub 4}@mSiO{sub 2} can be a good adsorbent for the organic pollutant.

  18. Synthesis, Characterization and Utility of Carbon Nanotube Based Hybrid Sensors in Bioanalytical Applications

    Science.gov (United States)

    Badhulika, Sushmee

    The detection of gaseous analytes and biological molecules is of prime importance in the fields of environmental pollution control, food and water - safety and analysis; and medical diagnostics. This necessitates the development of advanced and improved technology that is reliable, inexpensive and suitable for high volume production. The conventional sensors are often thin film based which lack sensitivity due to the phenomena of current shunting across the charge depleted region when an analyte binds with them. One dimensional (1-D) nanostructures provide a better alternative for sensing applications by eliminating the issue of current shunting due to their 1-D geometries and facilitating device miniaturization and low power operations. Carbon nanotubes (CNTs) are 1-D nanostructures that possess small size, high mechanical strength, high electrical and thermal conductivity and high specific area that have resulted in their wide spread applications in sensor technology. To overcome the issue of low sensitivity of pristine CNTs and to widen their scope, hybrid devices have been fabricated that combine the synergistic properties of CNTs along with materials like metals and conducting polymers (CPs). CPs exhibit electronic, magnetic and optical properties of metals and semiconductors while retaining the processing advantages of polymers. Their high chemical sensitivity, room temperature operation and tunable charge transport properties has made them ideal for use as transducing elements in chemical sensors. In this dissertation, various CNT based hybrid devices such as CNT-conducting polymer and graphene-CNT-metal nanoparticles based sensors have been developed and demonstrated towards bioanalytical applications such as detection of volatile organic compounds (VOCs) and saccharides. Electrochemical polymerization enabled the synthesis of CPs and metal nanoparticles in a simple, cost effective and controlled way on the surface of CNT based platforms thus resulting in

  19. Template-free synthesis of fully collapsed carbon nanotubes and graphene nanoribbons by chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yong-Xing [School of Physics and Electronic Information, Huaibei Normal University, Huaibei 235000 (China); Jia, Yong, E-mail: yjiaahedu@163.com [School of Pharmacy, Anhui University of Chinese Medicine, Hefei 230012 (China)

    2015-12-01

    Highlights: • Commercial Fe{sub 2}O{sub 3} and Al{sub 2}O{sub 3} powders were chosen to prepare Fe{sub 2}O{sub 3}/Al{sub 2}O{sub 3} catalyst. • Fully collapsed carbon nanotubes and graphene nanoribbons were synthesized through the catalytic decomposition of methane at 900 °C. • The formation mechanism of the fully collapsed carbon nanotubes was revealed. - Abstract: Fe{sub 2}O{sub 3}/Al{sub 2}O{sub 3} catalyst was prepared by simply calcining the mixture of commercial Fe{sub 2}O{sub 3} and Al{sub 2}O{sub 3} powders at 1000 °C. The obtained Fe{sub 2}O{sub 3}/Al{sub 2}O{sub 3} catalyst shows high efficiency for the synthesis of fully collapsed carbon nanotubes and graphene nanoribbons through the catalytic decomposition of methane at 900 °C. The yield of the fully collapsed carbon nanotubes and graphene nanoribbons was 19.5 wt%. Field emission scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy and thermal gravimetric analysis were used to characterize the products. A tip-growth mechanism for the fully collapsed carbon nanotubes was suggested based on the SEM and TEM images of products produced at the initial stage. The break through of the catalyst particle from graphite layers resulted in the crack and then cut open of the fully collapsed carbon nanotubes, which further resulted in the formation of the graphene nanoribbons.

  20. Synthesis of carbon nanotubes by gasification of petroleum coke

    International Nuclear Information System (INIS)

    Abdullayeva, S.H.; Musayeva, N.N.; Jabbarov, R.B.; Abdullayeva, S.H.; Musayeva, N.N.; Jabbarov, R.B.; Matsuda, T.

    2013-01-01

    Carbon nanotubes have been synthesized by using petroleum coke (PC) as carbon source. Different positions of the PC in the reactor chamber and some other factors markedly increase quantity of the synthesized CNTs and lead to changing of their characteristics such as crystallinity, diameter, straight and etc. confirmed by scanning electron microscope (SEM), transmission electron microscope (TEM) studies.The thickness of the Fe catalyst deposited on Si and SiO 2 substrates strongly influence to the quality, quantity and uniformity of the grown CNTs. Wet-coated thin films of FeCl 2 works well as catalyst, which can be profitable for mass production of CNTs

  1. Synthesis of carbon nanotubes using natural carbon precursor: Castor oil

    Science.gov (United States)

    Raziah, A. Z.; Junizah, A. R.; Saifuddin, N.

    2012-09-01

    Castor oil has long been an article of commerce due to its versatility as it is widely used as a starting material for many industrial chemical products because of its unique structure. In this study, carbon nanotubes has been synthesized by thermal decomposition of castor oil in nitrogen atmosphere at 300-400δC using custom-made microwave processing unit. The precursor material was catalyzed by iron clusters originating from the addition of ferrocene. The morphology and characterization of the CNTs were studied and discussed by transmission electron microscopy (TEM).

  2. Fiber Optic Chemical Nanosensors Based on Engineered Single-Walled Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    M. Consales

    2008-01-01

    Full Text Available In this contribution, a review of the development of high-performance optochemical nanosensors based on the integration of carbon nanotubes with the optical fiber technology is presented. The paper first provide an overview of the amazing features of carbon nanotubes and their exploitation as highly adsorbent nanoscale materials for gas sensing applications. Successively, the attention is focused on the operating principle, fabrication, and characterization of fiber optic chemosensors in the Fabry-Perot type reflectometric configuration, realized by means of the deposition of a thin layer of single-walled carbon nanotubes (SWCNTs upon the distal end of standard silica optical fibers. This is followed by an extensive review of the excellent sensing capabilities of the realized SWCNTs-based chemical nanosensors against volatile organic compounds and other pollutants in different environments (air and water and operating conditions (room temperature and cryogenic temperatures. The experimental results reported here reveal that ppm and sub-ppm chemical detection limits, low response times, as well as fast and complete recovery of the sensor responses have been obtained in most of the investigated cases. This evidences the great potentialities of the proposed photonic nanosensors based on SWCNTs to be successfully employed for practical environmental monitoring applications both in liquid and vapor phase as well as for space. Furthermore, the use of novel SWCNTs-based composites as sensitive fiber coatings is proposed to enhance the sensing performance and to improve the adhesion of carbon nanotubes to the fiber surface. Finally, new advanced sensing configurations based on the use of hollow-core optical fibers coated and partially filled by carbon nanotubes are also presented.

  3. Metal-filled carbon nanotube based optical nanoantennas: bubbling, reshaping, and in situ characterization.

    Science.gov (United States)

    Fan, Zheng; Tao, Xinyong; Cui, Xudong; Fan, Xudong; Zhang, Xiaobin; Dong, Lixin

    2012-09-21

    Controlled fabrication of metal nanospheres on nanotube tips for optical antennas is investigated experimentally. Resembling soap bubble blowing using a straw, the fabrication process is based on nanofluidic mass delivery at the attogram scale using metal-filled carbon nanotubes (m@CNTs). Two methods have been investigated including electron-beam-induced bubbling (EBIB) and electromigration-based bubbling (EMBB). EBIB involves the bombardment of an m@CNT with a high energy electron beam of a transmission electron microscope (TEM), with which the encapsulated metal is melted and flowed out from the nanotube, generating a metallic particle on a nanotube tip. In the case where the encapsulated materials inside the CNT have a higher melting point than what the beam energy can reach, EMBB is an optional process to apply. Experiments show that, under a low bias (2.0-2.5 V), nanoparticles can be formed on the nanotube tips. The final shape and crystallinity of the nanoparticles are determined by the cooling rate. Instant cooling occurs with a relatively large heat sink and causes the instant shaping of the solid deposit, which is typically similar to the shape of the molten state. With a smaller heat sink as a probe, it is possible to keep the deposit in a molten state. Instant cooling by separating the deposit from the probe can result in a perfect sphere. Surface and volume plasmons characterized with electron energy loss spectroscopy (EELS) prove that resonance occurs between a pair of as-fabricated spheres on the tip structures. Such spheres on pillars can serve as nano-optical antennas and will enable devices such as scanning near-field optical microscope (SNOM) probes, scanning anodes for field emitters, and single molecule detectors, which can find applications in bio-sensing, molecular detection, and high-resolution optical microscopy.

  4. Fabrication of Vertically Aligned Carbon Nanotube or Zinc Oxide Nanorod Arrays for Optical Diffraction Gratings.

    Science.gov (United States)

    Kim, Jeong; Kim, Sun Il; Cho, Seong-Ho; Hwang, Sungwoo; Lee, Young Hee; Hur, Jaehyun

    2015-11-01

    We report on new fabrication methods for a transparent, hierarchical, and patterned electrode comprised of either carbon nanotubes or zinc oxide nanorods. Vertically aligned carbon nanotubes or zinc oxide nanorod arrays were fabricated by either chemical vapor deposition or hydrothermal growth, in combination with photolithography. A transparent conductive graphene layer or zinc oxide seed layer was employed as the transparent electrode. On the patterned surface defined using photoresist, the vertically grown carbon nanotubes or zinc oxides could produce a concentrated electric field under applied DC voltage. This periodic electric field was used to align liquid crystal molecules in localized areas within the optical cell, effectively modulating the refractive index. Depending on the material and morphology of these patterned electrodes, the diffraction efficiency presented different behavior. From this study, we established the relationship between the hierarchical structure of the different electrodes and their efficiency for modulating the refractive index. We believe that this study will pave a new path for future optoelectronic applications.

  5. Electrochemical method for rapid synthesis of Zinc Pentacyanonitrosylferrate Nanotubes

    Directory of Open Access Journals (Sweden)

    Rogaieh Bargeshadi

    2014-10-01

    Full Text Available In this paper, a rapid and simple approach was developed for the preparation of zinc pentacyanonitrosylferrate nanotubes (ZnPCNF NTs within the cylindrical pores of anodic aluminum oxide (AAO template by electrochemical method. The AAO was fabricated in two steps anodizing from aluminum foil. The first anodization of aluminum foil was performed in 0.2 mol L-1 H2C2O4 followed by removal of the formed porous oxide film by a solution of 6 wt% of phosphoric acid. The second anodization step was then performed using the same conditions as the previous step. Scanning electron microscope (SEM and X-ray diffraction (XRD method were employed to characterize the resulting highly oriented uniform hollow tube array which its diameter was in the range of 25-75 nm depending on the applied voltage and the length of nanotubes was equal to the thickness of AAO which was about 2 m. The growth properties of the ZnPCNF NTs array film can be achieved by controlling the structure of the template and applied potential across the cell.

  6. Synthesis and properties of Fe/Ni nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Kozlovskiy, A. L., E-mail: artem88sddt@mail.ru; Zdorovets, M. V. [Institute of Nuclear Physics (Kazakhstan); Kadyrzhanov, K. K. [Eurasian National University (Kazakhstan)

    2016-09-15

    Fe/Ni nanotubes were formed in pores of polyethylenterephtalate-based template matrices by electrochemical deposition. The inner diameter, wall height, and thickness of the nanostructures, as well as the elemental and phase compositions, can be controlled by varying the deposition conditions. The volume deposition rate constants have been determined for each potential difference, due to which the nanostructure growth could be controlled. An X-ray diffraction analysis of the samples obtained at a potential difference of 1-1.6 V has revealed their composition to correspond to the substitutional solid solution, with an iron atom replaced by a nickel atom and dominance of the bcc a-Fe phase. The samples obtained at a potential difference of 1.8–2 V contain the bcc a-Fe phase and fcc Ni phase; the fcc phase dominates in the sample obtained at a potential difference of 2 V, which can be related to the high Ni content in nanotubes.

  7. Influence of synthesis parameters on CCVD growth of vertically aligned carbon nanotubes over aluminum substrate.

    Science.gov (United States)

    Szabó, Anna; Kecsenovity, Egon; Pápa, Zsuzsanna; Gyulavári, Tamás; Németh, Krisztián; Horvath, Endre; Hernadi, Klara

    2017-08-25

    In the past two decades, important results have been achieved in the field of carbon nanotube (CNT) research, which revealed that carbon nanotubes have extremely good electrical and mechanical properties The range of applications widens more, if CNTs form a forest-like, vertically aligned structure (VACNT) Although, VACNT-conductive substrate structure could be very advantageous for various applications, to produce proper system without barrier films i.e. with good electrical contact is still a challenge. The aim of the current work is to develop a cheap and easy method for growing carbon nanotubes forests on conductive substrate with the CCVD (Catalytic Chemical Vapor Deposition) technique at 640 °C. The applied catalyst contained Fe and Co and was deposited via dip coating onto an aluminum substrate. In order to control the height of CNT forest several parameters were varied during the both catalyst layer fabrication (e.g. ink concentration, ink composition, dipping speed) and the CCVD synthesis (e.g. gas feeds, reaction time). As-prepared CNT forests were investigated with various methods such as scanning electron microscopy, Raman spectroscopy, and cyclic voltammetry. With such an easy process it was possible to tune both the height and the quality of carbon nanotube forests.

  8. Template directed synthesis of plasmonic gold nanotubes with tunable IR absorbance.

    Science.gov (United States)

    Bridges, Colin R; Schon, Tyler B; DiCarmine, Paul M; Seferos, Dwight S

    2013-04-01

    A nearly parallel array of pores can be produced by anodizing aluminum foils in acidic environments. Applications of anodic aluminum oxide (AAO) membranes have been under development since the 1990's and have become a common method to template the synthesis of high aspect ratio nanostructures, mostly by electrochemical growth or pore-wetting. Recently, these membranes have become commercially available in a wide range of pore sizes and densities, leading to an extensive library of functional nanostructures being synthesized from AAO membranes. These include composite nanorods, nanowires and nanotubes made of metals, inorganic materials or polymers. Nanoporous membranes have been used to synthesize nanoparticle and nanotube arrays that perform well as refractive index sensors, plasmonic biosensors, or surface enhanced Raman spectroscopy (SERS) substrates, as well as a wide range of other fields such as photo-thermal heating, permselective transport, catalysis, microfluidics, and electrochemical sensing. Here, we report a novel procedure to prepare gold nanotubes in AAO membranes. Hollow nanostructures have potential application in plasmonic and SERS sensing, and we anticipate these gold nanotubes will allow for high sensitivity and strong plasmon signals, arising from decreased material dampening.

  9. Effect of synthesis parameters on morphology of polyaniline (PANI) and field emission investigation of PANI nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Bankar, Prashant K.; More, Mahendra A., E-mail: mam@physics.unipune.ac.in [Center for Advanced Studies in Materials Science and Condensed Matter Physics, Department of Physics, University of Pune, Pune-411007 (India); Patil, Sandip S. [Department of Physics, Modern College of Arts, Science and Commerce, Shivajinagar, Pune-411005. India (India)

    2015-06-24

    Polyaniline (PANI) nanostructures have been synthesized by simple chemical oxidation route at different monomer concentration along with variation in synthesis temperature. The effect of variation of synthesis parameters has been revealed using different characterization techniques. The structural and morphological characterization of the synthesized PANI nanostructures was carried out by scanning electron microscopy (SEM), transmission electron microscopy (TEM), whereas Fourier Transform Infrared spectroscopy (FTIR) has been used to reveal the chemical properties. With the variation in the synthesis temperature and monomer concentration, various morphologies characterized by formation of PANI nanoparticles, nanofibres, nanotubes and nanospheres, are revealed from the SEM analysis. The FTIR analysis reveals the formation of conducting state of PANI under prevailing experimental conditions. The field emission investigation of the conducting PANI nanotubes was performed in all metal UHV system at base pressure of 1x10{sup −8} mbar. The turn on field required to draw emission of 1 nA current was observed to be ∼ 2.2 V/μm and threshold field (corresponding to emission current density of 1 µA/cm2) was found to be 3.2 V/μm. The emission current was observed to be stable for more than three hours at a preset value 1 µA. The simple synthesis route and good field emission characteristics indicate potential of PANI nanofibres as a promising emitter for field emission based micro/nano devices.

  10. Titanate nanotubes sensitized with silver nanoparticles: Synthesis, characterization and in-situ pollutants photodegradation

    Energy Technology Data Exchange (ETDEWEB)

    Barrocas, B.; Nunes, C.D. [Centro de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa (Portugal); Carvalho, M.L. [LIBPhys-UNL, Laboratório de Instrumentação, Engenharia Biomédica e Física da Radiação and Departamento de Física da Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Monteiro, O.C., E-mail: ocmonteiro@ciencias.ulisboa.pt [Centro de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa (Portugal)

    2016-11-01

    Highlights: • Combination of titanate nanotubes with crystalline silver nanoparticles is described. • AgHTNT demonstrated high photocatalytic activity for hydroxyl radical production. • AgHTNT exhibits the best photocatalytic activity for phenol removal. • Recycling does not affect AgHTNT photocatalytic performance. • Silver nanoparticles growth continues during several irradiation cycles. - Abstract: In this work, titanate nanotubes were modified with silver nanoparticles to produce new nanocomposite materials with enhanced photocatalytic activity for phenol removal. The TNTs were produced using a hydrothermal approach and, after being submitted to an Ag{sup +} exchange process, metallic Ag nanoparticles were obtained over the nanotubes surface. The prepared materials were structural, morphological and optical characterized by X-ray powder diffraction, micro X-ray fluorescence, transmission electron microscopy, diffused reflectance spectroscopy and X-ray photoelectron spectroscopy. The characterization results indicate that Ag{sup +} was immobilized not only in the nanotubes external surface but mainly in the TiO{sub 6} interlayers space. The application of this new nanocomposite material on photocatalytic degradation of pollutants was investigated. First, the evaluation of hydroxyl radical formation, using the terephthalic acid as a probe was studied. The photocatalytic activity of the sensitized materials for phenol degradation was afterwards evaluated. The results show that the nanocomposite sample is the best catalyst, achieving 98.0% photodegradation efficiency of a 0.2 mM phenol solution within 20 min under UV–vis radiation. The reusability of the prepared samples as photocatalysts was evaluated in four successive degradation assays, using fresh phenol solutions. The sensitized sample demonstrated excellent catalytic reusability ability, without loss of photochemical stability. The structural and morphological characterization during these

  11. Optical nanoparticles: synthesis and biomedical application

    International Nuclear Information System (INIS)

    Nhung Tran, Hong; Lien Nghiem, Thi Ha; Duong Vu, Thi Thuy; Ha Chu, Viet; Hoa Do, Quang; Vu, Duong; Nghia Nguyen, Trong; Tan Pham, Minh; Son Vu, Van; Nguyen, Thi Thuy; Ngoc Nguyen, Thi Bich; Duc Tran, Anh; Trinh, Thi Thuong; Huan Le, Quang; Thuan Tong, Kim; Thuy Tran, Thanh; Hoang, Thi My Nhung; Thanh Nguyen, Lai; Nguyen Duong, Cao; Minh Pham, Duc

    2015-01-01

    This paper presents a summary of our results on studies of synthesis and biomedical application of optical nanoparticles. Gold, dye-doped silica based and core–shell multifunctional multilayer (SiO_2/Au, Fe_3O_4/SiO_2, Fe_3O_4/SiO_2/Au) water-monodispersed nanoparticles were synthesized by chemical route and surface modified with proteins and biocompatible chemical reagents. The particles were conjugated with antibody or aptamer for specific detecting and imaging bacteria and cancer cells. The photothermal effects of gold nanoshells (SiO_2/Au and Fe_3O_4/SiO_2/Au) on cells and tissues were investigated. The nano silver substrates were developed for surface enhanced Raman scattering (SERS) spectroscopy to detect melamine. (review)

  12. Carbon-coated SnO2 nanotubes: template-engaged synthesis and their application in lithium-ion batteries

    Science.gov (United States)

    Wu, Ping; Du, Ning; Zhang, Hui; Yu, Jingxue; Qi, Yue; Yang, Deren

    2011-02-01

    This paper reports the synthesis of carbon-coated SnO2 (SnO2-C) nanotubes through a simple glucose hydrothermal and subsequent carbonization approach by using Sn nanorods as sacrificial templates. The as-synthesized SnO2-C nanotubes have been applied as anode materials for lithium-ion batteries, which exhibit improved cyclic performance compared to pure SnO2 nanotubes. The hollow nanostructure, together with the carbon matrix which has good buffering effect and high electronic conductivity, can be responsible for the improved cyclic performance.

  13. Application of carbon nanotubes to topographical resolution enhancement of tapered fiber scanning near field optical microscopy probes

    Science.gov (United States)

    Huntington, S. T.; Jarvis, S. P.

    2003-05-01

    Scanning near field optical microscopy (SNOM) probes are typically tapered optical fibers with metallic coatings. The tip diameters are generally in excess of 300 nm and thus provide poor topographical resolution. Here we report on the attachment multiwalled carbon nanotubes to the probes in order to substantially enhance the topographical resolution, without adversely affecting the optical resolution.

  14. Characterization of electrosynthesized conjugated polymer-carbon nanotube composite: optical nonlinearity and electrical property.

    Science.gov (United States)

    Bahrami, Afarin; Talib, Zainal Abidin; Shahriari, Esmaeil; Yunus, Wan Mahmood Mat; Kasim, Anuar; Behzad, Kasra

    2012-01-01

    The effects of multi-walled carbon nanotube (MWNT) concentration on the structural, optical and electrical properties of conjugated polymer-carbon nanotube composite are discussed. Multi-walled carbon nanotube-polypyrrole nanocomposites were synthesized by electrochemical polymerization of monomers in the presence of different amounts of MWNTs using sodium dodecylbenzensulfonate (SDBS) as surfactant at room temperature and normal pressure. Field emission scanning electron microscopy (FESEM) indicates that the polymer is wrapped around the nanotubes. Measurement of the nonlinear refractive indices (n(2)) and the nonlinear absorption (β) of the samples with different MWNT concentrations measurements were performed by a single Z-scan method using continuous wave (CW) laser beam excitation wavelength of λ = 532 nm. The results show that both nonlinear optical parameters increased with increasing the concentration of MWNTs. The third order nonlinear susceptibilities were also calculated and found to follow the same trend as n(2) and β. In addition, the conductivity of the composite film was found to increase rapidly with the increase in the MWNT concentration.

  15. Polyaniline/carbon nanotube/CdS quantum dot composites with enhanced optical and electrical properties

    Energy Technology Data Exchange (ETDEWEB)

    Goswami, Mrinmoy [Department of Physics, National Institute of Technology, Durgapur, 713209 (India); Ghosh, Ranajit, E-mail: ghosh.ranajit@gmail.com [CSIR-Central Mechanical Engineering Research Institute, Durgapur, 713209 (India); Maruyama, Takahiro [Department of Applied Chemistry, Meijo University, Nagoya, 4688502 (Japan); Meikap, Ajit Kumar [Department of Physics, National Institute of Technology, Durgapur, 713209 (India)

    2016-02-28

    Graphical abstract: - Highlights: • A new kind of polyaniline/carbon nanotube/CdS quantum dot composites have been synthesized via in-situ polymerization of aniline monomer. • A degree of increase in conductivity. • Size-dependent optical properties of CdS quantum dots have been observed. - Abstract: A new kind of polyaniline/carbon nanotube/CdS quantum dot composites have been developed via in-situ polymerization of aniline monomer in the presence of dispersed CdS quantum dots (size: 2.7–4.8 nm) and multi-walled carbon nanotubes (CNT), which exhibits enhanced optical and electrical properties. The existences of 1st order, 2nd order, and 3rd order longitudinal optical phonon modes, strongly indicate the high quality of synthesized CdS quantum dots. The occurrence of red shift of free exciton energy in photoluminescence is due to size dependent quantum confinement effect of CdS. The conductivity of the composites (for example PANI/CNT/CdS (2 wt.% CdS)) is increased by about 7 of magnitude compared to that of pure PANI indicating a charge transfer between CNT and polymer via CdS quantum dots. This advanced material has a great potential for high-performance of electro-optical applications.

  16. Effective synthesis of silicon carbide nanotubes by microwave heating of blended silicon dioxide and multi-walled carbon nanotube

    Energy Technology Data Exchange (ETDEWEB)

    Tony, Voo Chung Sung; Voon, Chun Hong; Lee, Chang Chuan and others, E-mail: chvoon@unimap.edu.my [Institute of Nano Electronic Engineering, University Malaysia (Malaysia)

    2017-11-15

    Silicon carbide nanotube (SiCNTs) has been proven as a suitable material for wide applications in high power, elevated temperature and harsh environment. For the first time, we reported in this article an effective synthesis of SiCNTs by microwave heating of SiO{sub 2} and MWCNTs in molar ratio of 1:1, 1:3, 1:5 and 1:7. Blend of SiO{sub 2} and MWCNTs in the molar ratio of 1:3 was proven to be the most suitable for the high yield synthesis of β-SiCNTs as confirmed by X-ray diffraction pattern. Only SiCNTs were observed from the blend of MWCNTs and SiO{sub 2} in the molar ratio of 1:3 from field emission scanning electron microscopy imaging. High magnification transmission electron microscopy showed that tubular structure of MWCNT was preserved with the inter-planar spacing of 0.25 nm. Absorption bands of Si-C bond were detected at 803 cm-1 in Fourier transform infrared spectrum. Thermal gravimetric analysis revealed that SiCNTs from ratio of 1:3 showed the lowest weight loss. Thus, our synthetic process indicates high yield conversion of SiO{sub 2} and MWCNTs to SiCNTs was achieved for blend of SiO{sub 2} and MWCNTs in molar ratio of 1:3. (author)

  17. Laser ablation for the synthesis of carbon nanotubes

    Science.gov (United States)

    Holloway, Brian C.; Eklund, Peter C.; Smith, Michael W.; Jordan, Kevin C.; Shinn, Michelle

    2010-04-06

    Single walled carbon nanotubes are produced in a novel apparatus by the laser-induced ablation of moving carbon target. The laser used is of high average power and ultra-fast pulsing. According to various preferred embodiments, the laser produces an output above about 50 watts/cm.sup.2 at a repetition rate above about 15 MHz and exhibits a pulse duration below about 10 picoseconds. The carbon, carbon/catalyst target and the laser beam are moved relative to one another and a focused flow of "side pumped", preheated inert gas is introduced near the point of ablation to minimize or eliminate interference by the ablated plume by removal of the plume and introduction of new target area for incidence with the laser beam. When the target is moved relative to the laser beam, rotational or translational movement may be imparted thereto, but rotation of the target is preferred.

  18. Laser ablation for the synthesis of carbon nanotubes

    Science.gov (United States)

    Holloway, Brian C. (Inventor); Eklund, Peter C. (Inventor); Smith, Michael W. (Inventor); Jordan, Kevin C. (Inventor); Shinn, Michelle (Inventor)

    2012-01-01

    Single walled carbon nanotubes are produced in a novel apparatus by the laser-induced ablation of moving carbon target. The laser used is of high average power and ultra-fast pulsing. According to various preferred embodiments, the laser produces and output above about 50 watts/cm.sup.2 at a repetition rate above about 15 MHz and exhibits a pulse duration below about 10 picoseconds. The carbon, carbon/catalyst target and the laser beam are moved relative to one another and a focused flow of "side pumped", preheated inert gas is introduced near the point of ablation to minimize or eliminate interference by the ablated plume by removal of the plume and introduction of new target area for incidence with the laser beam. When the target is moved relative to the laser beam, rotational or translational movement may be imparted thereto, but rotation of the target is preferred.

  19. Green Synthesis and Characterization of Carbon Nanotubes/Polyaniline Nanocomposites

    Directory of Open Access Journals (Sweden)

    Van Hoa Nguyen

    2015-01-01

    Full Text Available Carbon nanotubes/polyaniline (CNT/PANI nanocomposites were synthesized by the interfacial polymerization of aniline in the presence of CNTs using two green solvents, water and an ionic liquid (1-butyl-3-methylimidazolium tetrafluoroborate, [bmim][BF4], as the two phases. The formation and incorporation of PANI on the surface of the CNTs were confirmed by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy ultraviolet-visible spectroscopy, and X-ray photoelectron spectroscopy. The analyses showed that the surface of the CNTs was coated with different morphologies of thin PANI layers depending on whether a HCl or HNO3 solution was used. The thermal stability of the composites was much better than that of the bare CNTs and pure PANI. The as-prepared composites were also used to modify the nickel foam electrodes for characterization of the electrochemical properties.

  20. Synthesis and luminescence properties for europium oxide nanotubes

    International Nuclear Information System (INIS)

    Mo Zunli; Deng Zhepeng; Guo Ruibin; Fu Qiangang; Feng Chao; Liu Pengwei; Sun Yu

    2012-01-01

    Highlights: ► A novel high temperature sensitive fluorescent CNTs/Eu 2 O 3 nanocomposite was fabricated. ► The nanocomposite showed strong fluorescent emission peaks at around 540 and 580 nm after calcined beyond 620 °C for 4 h. ► The ultrahigh fluorescence intensity of the nanocomposites resulted from a synergetic effect of CNTs and europium oxide. ► We also discovered that CNTs had an effect of fluorescence quenching. - Abstract: A novel high temperature sensitive fluorescent nanocomposite has been successfully synthesized by an economic hydrothermal method using carbon nanotubes (CNTs), europium oxide, and sodium dodecyl benzene sulfonate (SDBS). To our great interest, the nanocomposites show high temperature sensitivity after calcinations at various temperatures, suggesting a synergetic effect of CNTs and europium oxide which leads to ultrahigh fluorescence intensity of europium oxide nanotubes. When the novel high temperature sensitive fluorescent nanocomposites were calcined beyond 620 °C for 4 h, the obtained nanocomposites have a strong emission peak at around 540 and 580 nm, due to the 5 D 0 → 7 F j (j = 0, 1) forced electric dipole transition of Eu 3+ ions. In turn, the emission spectra showed a slight blue shift. The intensity of this photoluminescence (PL) band is remarkably temperature-dependent and promotes strongly beyond 620 °C. This novel feature is attributed to the thermally activated carrier transfer process from nanocrystals and charged intrinsic defects states to Eu 3+ energy levels. The novel high temperature sensitive fluorescent nanocomposite has potential applications in high temperature warning materials, sensors and field emission displays. It is also interesting to discover that CNTs have the effect of fluorescence quenching.

  1. Ferromagnetic filled carbon nanotubes and nanoparticles: synthesis and lipid-mediated delivery into human tumor cells

    International Nuclear Information System (INIS)

    Moench, I.; Meye, A.; Leonhardt, A.; Kraemer, K.; Kozhuharova, R.; Gemming, T.; Wirth, M.P.; Buechner, B.

    2005-01-01

    We describe the synthesis and the properties of Fe-filled multi-walled carbon nanotubes (MWNTs) and nanoparticles (NP) produced by chemical vapor deposition (CVD). We have employed ferrocene as a starting substance and oxidized Si-wafers as substrates. The magnetic properties and the interaction of the material with bladder cancer cells were determined. After the addition of NP suspensions to cultured cells, no adhesion of the nanoparticles/nanotubes (NT/NP) to the cell membrane and also no cellular uptake were observed. However, the preincubation of the (NT/NP) suspension with cationic lipid caused an efficient delivery of the lipid-nanostructure complexes into the cytoplasm within 2 h after adding to the culture medium

  2. Synthesis of carbon nanotubes by pyrolysis of solid Ni(dmg)2

    International Nuclear Information System (INIS)

    Kordatos, K.; Vlasopoulos, A.D.; Strikos, S.; Ntziouni, A.; Gavela, S.; Trasobares, S.; Kasselouri-Rigopoulou, V.

    2009-01-01

    We describe the high yield synthesis of multi-walled carbon nanotubes (MWCNTs) and the determination of the optimum production conditions. The method involves the catalytic pyrolysis of solid Ni(dmg) 2 under an Ar atmosphere. The obtained materials were characterized by scanning electron microscopy (SEM), energy dispersive X-ray (EDX) analysis, high resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), Raman spectroscopy and thermogravimetry analysis (TGA). The data revealed the formation of MWCNTs surrounded by a varying quantity of byproducts such as amorphous carbon and metallic particles, depending mainly on the reaction temperature. Pyrolysis of Ni(dmg) 2 at 900 deg. C results in the production of nanotube material with the highest degree of crystallinity

  3. Single Molecule Detection in Living Biological Cells using Carbon Nanotube Optical Probes

    Science.gov (United States)

    Strano, Michael

    2009-03-01

    Nanoscale sensing elements offer promise for single molecule analyte detection in physically or biologically constrained environments. Molecular adsorption can be amplified via modulation of sharp singularities in the electronic density of states that arise from 1D quantum confinement [1]. Single-walled carbon nanotubes (SWNT), as single molecule optical sensors [2-3], offer unique advantages such as photostable near-infrared (n-IR) emission for prolonged detection through biological media, single-molecule sensitivity and, nearly orthogonal optical modes for signal transduction that can be used to identify distinct classes of analytes. Selective binding to the SWNT surface is difficult to engineer [4]. In this lecture, we will briefly review the immerging field of fluorescent diagnostics using band gap emission from SWNT. In recent work, we demonstrate that even a single pair of SWNT provides at least four optical modes that can be modulated to uniquely fingerprint chemical agents by the degree to which they alter either the emission band intensity or wavelength. We validate this identification method in vitro by demonstrating detection and identification of six genotoxic analytes, including chemotherapeutic drugs and reactive oxygen species (ROS), which are spectroscopically differentiated into four distinct classes. We also demonstrate single-molecule sensitivity in detecting hydrogen peroxide, one of the most common genotoxins and an important cellular signal. Finally, we employ our sensing and fingerprinting method of these analytes in real time within live 3T3 cells, demonstrating the first multiplexed optical detection from a nanoscale biosensor and the first label-free tool to optically discriminate between genotoxins. We will also discuss our recent efforts to fabricate biomedical sensors for real time detection of glucose and other important physiologically relevant analytes in-vivo. The response of embedded SWNT in a swellable hydrogel construct to

  4. Facile radiolytic synthesis of ruthenium nanoparticles on graphene oxide and carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Rojas, J.V., E-mail: jvrojas@vcu.edu [Mechanical and Nuclear Engineering Department, Virginia Commonwealth University, 401 West Main Street, Richmond, Virginia, 23284 (United States); Toro-Gonzalez, M.; Molina-Higgins, M.C. [Mechanical and Nuclear Engineering Department, Virginia Commonwealth University, 401 West Main Street, Richmond, Virginia, 23284 (United States); Castano, C.E., E-mail: cecastanolond@vcu.edu [Nanomaterials Core Characterization Facility, Chemical and Life Science Engineering Department, Virginia Commonwealth University, 601 West Main Street, Richmond, Virginia, 23284 (United States)

    2016-03-15

    Graphical abstract: - Highlights: • Facile radiolytic synthesis of Ru nanoparticles on graphene oxide and carbon nanotubes. • Homogeneously distributed Rh nanoparticles on supports are ∼2.5 nm in size. • Simultaneous reduction of graphene oxide and Ru ions occurs during the synthesis. • Ru-O bonds evidenced the interaction of the nanoparticles with the support. - Abstract: Ruthenium nanoparticles on pristine (MWCNT) and functionalized carbon nanotubes (f-MWCNT), and graphene oxide have been prepared through a facile, single step radiolytic method at room temperature, and ambient pressure. This synthesis process relies on the interaction of high energy gamma rays from a {sup 60}Co source with the water in the aqueous solutions containing the Ru precursor, leading to the generation of highly reducing species that further reduce the Ru metal ions to zero valence state. Transmission electron microscopy and X-Ray diffraction revealed that the nanoparticles were homogeneously distributed on the surface of the supports with an average size of ∼2.5 nm. X-ray Photoelectron spectroscopy analysis showed that the interaction of the Ru nanoparticles with the supports occurred through oxygenated functionalities, creating metal-oxygen bonds. This method demonstrates to be a simple and clean approach to produce well dispersed nanoparticles on the aforementioned supports without the need of any hazardous chemical.

  5. Facile radiolytic synthesis of ruthenium nanoparticles on graphene oxide and carbon nanotubes

    International Nuclear Information System (INIS)

    Rojas, J.V.; Toro-Gonzalez, M.; Molina-Higgins, M.C.; Castano, C.E.

    2016-01-01

    Graphical abstract: - Highlights: • Facile radiolytic synthesis of Ru nanoparticles on graphene oxide and carbon nanotubes. • Homogeneously distributed Rh nanoparticles on supports are ∼2.5 nm in size. • Simultaneous reduction of graphene oxide and Ru ions occurs during the synthesis. • Ru-O bonds evidenced the interaction of the nanoparticles with the support. - Abstract: Ruthenium nanoparticles on pristine (MWCNT) and functionalized carbon nanotubes (f-MWCNT), and graphene oxide have been prepared through a facile, single step radiolytic method at room temperature, and ambient pressure. This synthesis process relies on the interaction of high energy gamma rays from a "6"0Co source with the water in the aqueous solutions containing the Ru precursor, leading to the generation of highly reducing species that further reduce the Ru metal ions to zero valence state. Transmission electron microscopy and X-Ray diffraction revealed that the nanoparticles were homogeneously distributed on the surface of the supports with an average size of ∼2.5 nm. X-ray Photoelectron spectroscopy analysis showed that the interaction of the Ru nanoparticles with the supports occurred through oxygenated functionalities, creating metal-oxygen bonds. This method demonstrates to be a simple and clean approach to produce well dispersed nanoparticles on the aforementioned supports without the need of any hazardous chemical.

  6. Carbon Nanotube Membranes: Synthesis, Properties, and Future Filtration Applications

    Directory of Open Access Journals (Sweden)

    Md. Harun-Or Rashid

    2017-05-01

    Full Text Available Over the course of the past decade, there has been growing interest in the development of different types of membranes composed of carbon nanotubes (CNTs, including buckypapers and composite materials, for an ever-widening range of filtration applications. This article provides an overview of how different types of CNT membranes are prepared and the results obtained from investigations into their suitability for different applications. The latter involve the removal of small particles from air samples, the filtration of aqueous solutions containing organic compounds and/or bacteria, and the separation of individual liquids present in mixtures. A growing number of reports have demonstrated that the incorporation of CNTs into composite membranes confers an improved resistance to fouling caused by biomacromolecules and bacteria. These results are discussed, along with evidence that demonstrates it is possible to further reduce fouling by taking advantage of the inherent conductivity of composite membranes containing CNTs, as well as by using different types of electrochemical stimuli.

  7. Synthesis and characterization of new optically active poly(amide ...

    African Journals Online (AJOL)

    Synthesis and characterization of new optically active poly(amide-imide)s based on N -trimellitimido- ... Bulletin of the Chemical Society of Ethiopia ... (DMAc), dimethyl sulfoxide (DMSO) and N-methyl-2-pyrrolidone (NMP) at room temperature.

  8. Optical properties of spray coated layers with carbon nanotubes and graphene nanoplatelets

    Science.gov (United States)

    Lorenc, Zofia; Krzeminski, Jakub; Wroblewski, Grzegorz; Salbut, Leszek

    2016-04-01

    Carbon nanotubes as well as graphene are allotropic forms of carbon. Graphene is a two dimensional (2D) form of atomic-scale, hexagonal lattice, while carbon nanotube is a cylindrical nanostructure composed of a rolled sheet of graphene lattice at specific and discrete angles. Both of discussed materials have a high potential for modern engineering, especially in organic and printed electronics. High transparency in the visible part of the electromagnetic spectrum and low electrical resistance are desirable features in various applications and may be fulfilled with studied carbon nanomaterials. They have chances to become an important technological improvement in customers electronic devices by applying them to electrodes production in flexible screens and light sources. Graphene end carbon nanotubes are conceptually similar. However, characteristic properties of these two substances are different. In the article authors present the results of the transmission in visible electromagnetic spectrum characteristics of different samples. This parameter and the resistance of electrodes are tested, analysed and compared. Characteristics of optical transmittance against resistance with the optimal point of that relationship are presented in paper. Moreover, dependency of graphene nanoplatelets agglomerates arrangement against type of nano-fillers is shown. Two groups of tested inks contain graphene nanoplatelets with different fillers diameters. The third group contains carbon nanotubes. Described parameters are important for production process and results of analysis can be used by technologists working with elastic electronics.

  9. Direct synthesis of nitrogen-containing carbon nanotubes on carbon paper for fuel cell electrode

    Science.gov (United States)

    Yin, Wong Wai; Daud, Wan Ramli Wan; Mohamad, Abu Bakar; Kadhum, Abdul Amir Hassan; Majlan, Edy Herianto; Shyuan, Loh Kee

    2012-06-01

    Organic catalyst has recently been identified as the potential substitution for expensive platinum electrocatalyst for fuel cell application. Numerous studies have shown that the nitrogen-containing carbon nanotubes (N-CNT) can be synthesized through spray pyrolysis or floating chemical vapor deposition (CVD) technique using various type of organometallic as precursors. This paper presents the method of synthesis and the initial findings of the growth of N-CNT directly on carbon paper using a modified CVD technique. In this research, nickel (II) phthalocyanines (Ni-Pc) as precursor was dissolved in ethanol solvent, stirred and sonicated to become homogenized. The solution was poured into a bubbler and heated up to allow the mixture to vaporize. Subsequently, the solution vapor was flowed into the tubical reactor maintained at 900°C. Carbon paper sputtered with nickel nanoparticles was used as the substrate. The synthesized sample was examined through Field Emission Scanning Electron Microscopy (FESEM), Atomic Force Microscopy (AFM) and Fourier Transform Infra-Red (FTIR). Long, entangled and compartmentalized nanotubes with tube diameter ranging 23-27 nm were found covered the carbon paper surface with approximate of 5.5-6.0 μm in thickness. EDX analysis has successfully showed the presence of nitrogen in the carbon nanotube. FTIR analysis showed the presence of the C-N bond on CNT.

  10. Synthesis and characterization of carbon nanotube from coconut shells activated carbon

    Science.gov (United States)

    Melati, A.; Hidayati, E.

    2016-03-01

    Carbon nanotubes (CNTs) have been explored in almost every single cancer treatment modality, including drug delivery, lymphatic targeted chemotherapy, photodynamic therapy, and gene therapy. They are considered as one of the most promising nanomaterial with the capability of both detecting the cancerous cells and delivering drugs or small therapeutic molecules to the cells. CNTs have unique physical and chemical properties such as high aspect ratio, ultralight weight, high mechanical strength, high electrical conductivity, and high thermal conductivity. Coconut Shell was researched as active carbon source on 500 - 600°C. These activated carbon was synthesized becomes carbon nanotube and have been proposed as a promising tool for detecting the expression of indicative biological molecules at early stage of cancer. Clinically, biomarkers cancer can be detected by CNT Biosensor. We are using pyrolysis methods combined with CVD process or Wet Chemical Process on 600°C. Our team has successfully obtained high purity, and aligned MWCNT (Multi Wall Nanotube) bundles on synthesis CNT based on coconut shells raw materials. CNTs can be used to cross the mammalian cell membrane by endocytosis or other mechanisms. SEM characterization of these materials have 179 nm bundles on phase 83° and their materials compound known by using FTIR characterization.

  11. Synthesis of Carbon Nanotubes of Few Walls Using Aliphatic Alcohols as a Carbon Source

    Directory of Open Access Journals (Sweden)

    Francisco Espinosa-Magaña

    2013-06-01

    Full Text Available Carbon nanotubes with single and few walls are highly appreciated for their technological applications, regardless of the limited availability due to their high production cost. In this paper we present an alternative process that can lead to lowering the manufacturing cost of CNTs of only few walls by means of the use of the spray pyrolysis technique. For this purpose, ferrocene is utilized as a catalyst and aliphatic alcohols (methanol, ethanol, propanol or butanol as the carbon source. The characterization of CNTs was performed by scanning electron microscopy (SEM and transmission electron microscopy (TEM. The study of the synthesized carbon nanotubes (CNTs show important differences in the number of layers that constitute the nanotubes, the diameter length, the quantity and the quality as a function of the number of carbons employed in the alcohol. The main interest of this study is to give the basis of an efficient synthesis process to produce CNTs of few walls for applications where small diameter is required.

  12. Carbon nanotubes/magnetite hybrids prepared by a facile synthesis process and their magnetic properties

    International Nuclear Information System (INIS)

    Zhang Li; Ni, Qing-Qing; Natsuki, Toshiaki; Fu Yaqin

    2009-01-01

    In this paper, a facile synthesis process is proposed to prepare multiwalled carbon nanotubes/magnetite (MWCNTs/Fe 3 O 4 ) hybrids. The process involves two steps: (1) water-soluble CNTs are synthesized by one-pot modification using potassium persulfate (KPS) as oxidant. (2) Fe 3 O 4 is assembled along the treated CNTs by employing a facile hydrothermal process with the presence of hydrazine hydrate as the mineralizer. The treated CNTs can be easily dispersed in aqueous solvent. Moreover, X-ray photoelectron spectroscopy (XPS) analysis reveals that several functional groups such as potassium carboxylate (-COOK), carbonyl (-C=O) and hydroxyl (-C-OH) groups are formed on the nanotube surfaces. The MWCNTs/Fe 3 O 4 hybrids are characterized with respect to crystal structure, morphology, element composition and magnetic property by X-ray diffraction (XRD), transmission electron microscopy (TEM), XPS and superconducting quantum interference device (SQUID) magnetometer. XRD and TEM results show that the Fe 3 O 4 nanoparticles with diameter in the range of 20-60 nm were firmly assembled on the nanotube surface. The magnetic property investigation indicated that the CNTs/Fe 3 O 4 hybrids exhibit a ferromagnetic behavior and possess a saturation magnetization of 32.2 emu/g. Further investigation indicates that the size of assembled Fe 3 O 4 nanoparticles can be turned by varying experiment factors. Moreover, a probable growth mechanism for the preparation of CNTs/Fe 3 O 4 hybrids was discussed.

  13. Synthesis of Patterned Vertically Aligned Carbon Nanotubes by PECVD Using Different Growth Techniques: A Review.

    Science.gov (United States)

    Gangele, Aparna; Sharma, Chandra Shekhar; Pandey, Ashok Kumar

    2017-04-01

    Immense development has been taken place not only to increase the bulk production, repeatability and yield of carbon nanotubes (CNTs) in last 25 years but preference is also given to acknowledge the basic concepts of nucleation and growth methods. Vertically aligned carbon nanotubes (VAC-NTs) are forest of CNTs accommodated perpendicular on a substrate. Their exceptional chemical and physical properties along with sequential arrangement and dense structure make them suitable in various fields. The effect of different type of selected substrate, carbon precursor, catalyst and their physical and chemical status, reaction conditions and many other key parameters have been thoroughly studied and analysed. The aim of this paper is to specify the trend and summarize the effect of key parameters instead of only presenting all the experiments reported till date. The identified trends will be compared with the recent observations on the growth of different types of patterned VACNTs. In this review article, we have presented a comprehensive analysis of different techniques to precisely determine the role of different parameters responsible for the growth of patterned vertical aligned carbon nanotubes. We have covered various techniques proposed in the span of more than two decades to fabricate the different structures and configurations of carbon nanotubes on different types of substrates. Apart from a detailed discussion of each technique along with their specific process and implementation, we have also provided a critical analysis of the associated constraints, benefits and shortcomings. To sum it all for easy reference for researchers, we have tabulated all the techniques based on certain main key factors. This review article comprises of an exhaustive discussion and a handy reference for researchers who are new in the field of synthesis of CNTs or who wants to get abreast with the techniques of determining the growth of VACNTs arrays.

  14. Plasma-chemical synthesis of carbon nanotubes and fullerenes to create frost-resistant composite building materials

    International Nuclear Information System (INIS)

    Semenov, A P; Smirnyagina, N N; Tsyrenov, B O; Dasheev, D E; Khaltarov, Z M

    2017-01-01

    This paper considers a method of synthesis fullerenes and carbon nanotubes at atmospheric pressure. Carbon evaporates into the plasma arc. The paper discusses the method of synthesis of helium at a pressure of 10 5 Pa. We show the dependence yield of fullerenes and carbon nanotubes from the buffer gas pressure. It has been found that the fullerene yield increased with increasing pressure. The obtained fullerenes and nanotubes find their application in the modification of construction materials. The use of carbon nanomodifiers in the modification of the construction is promising since their introduction significantly improves the physico-mechanical properties using a small quantity of additives. With the introduction of the carbon nanomodifier decrease the porosity of cement stone, which leads to high strength and frost-resistant indicators of the modified cement. (paper)

  15. Study of the Reaction Rate of Gold Nanotube Synthesis from Sacrificial Silver Nanorods through the Galvanic Replacement Method

    Directory of Open Access Journals (Sweden)

    Sunil Kwon

    2010-01-01

    Full Text Available An investigation was carried out about the gold nanotube synthesis via a galvanic replacement reaction. The progress of the gold nanotube synthesis was investigated using electron microscopy and UV-Vis spectroscopy. In addition, the reaction rates of gold nanotube formation in the early stage of the reaction were studied. The chlorine ion concentration linearly increased with the gold precursor concentration but deviated from the stoichiometric amounts. This deviation was probably due to AgCl precipitates formed by the reaction of chlorine ions with dissolved silver ions. The replacement reaction was promoted with increased temperature and was nonlinearly proportional to the gold ion concentration. The outcomes of this research will enhance the current understanding of the galvanic replacement reaction.

  16. Synthesis of carbon nanotubes using the cobalt nanocatalyst by thermal chemical vapor deposition technique

    Energy Technology Data Exchange (ETDEWEB)

    Madani, S.S. [Department of Chemistry, Science and Research Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Zare, K. [Department of Chemistry, Science and Research Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Department of Chemistry, Shahid Beheshti University, Tehran (Iran, Islamic Republic of); Ghoranneviss, M. [Plasma Physics Research Center, Science and Research Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Salar Elahi, A., E-mail: Salari_phy@yahoo.com [Plasma Physics Research Center, Science and Research Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of)

    2015-11-05

    The three main synthesis methods of Carbon nanotubes (CNTs) are the arc discharge, the laser ablation and the chemical vapour deposition (CVD) with a special regard to the latter one. CNTs were produced on a silicon wafer by Thermal Chemical Vapor Deposition (TCVD) using acetylene as a carbon source, cobalt as a catalyst and ammonia as a reactive gas. The DC-sputtering system was used to prepare cobalt thin films on Si substrates. A series of experiments was carried out to investigate the effects of reaction temperature and deposition time on the synthesis of the nanotubes. The deposition time was selected as 15 and 25 min for all growth temperatures. Energy Dispersive X-ray (EDX) measurements were used to investigate the elemental composition of the Co nanocatalyst deposited on Si substrates. Atomic Force Microscopy (AFM) was used to characterize the surface topography of the Co nanocatalyst deposited on Si substrates. The as-grown CNTs were characterized under Field Emission Scanning Electron Microscopy (FESEM) to study the morphological properties of CNTs. Also, the grown CNTs have been investigated by High Resolution Transmission Electron Microscopy (HRTEM) and Raman spectroscopy. The results demonstrated that increasing the temperature leads to increasing the diameter of CNTs. The ideal reaction temperature was 850 °C and the deposition time was 15 min. - Graphical abstract: FESEM images of CNTs grown on the cobalt catalyst at growth temperatures of (a) 850 °C, (b) 900 °C, (c) 950 °C and (d) 1000 °C during the deposition time of 15 min. - Highlights: • Carbon nanotubes (CNTs) were produced on a silicon wafer by TCVD technique. • EDX and AFM were used to investigate the elemental composition and surface topography. • FESEM was used to study the morphological properties of CNTs. • The grown CNTs have been investigated by HRTEM and Raman spectroscopy.

  17. Long-chain amine-templated synthesis of gallium sulfide and gallium selenide nanotubes

    Science.gov (United States)

    Seral-Ascaso, A.; Metel, S.; Pokle, A.; Backes, C.; Zhang, C. J.; Nerl, H. C.; Rode, K.; Berner, N. C.; Downing, C.; McEvoy, N.; Muñoz, E.; Harvey, A.; Gholamvand, Z.; Duesberg, G. S.; Coleman, J. N.; Nicolosi, V.

    2016-06-01

    We describe the soft chemistry synthesis of amine-templated gallium chalcogenide nanotubes through the reaction of gallium(iii) acetylacetonate and the chalcogen (sulfur, selenium) using a mixture of long-chain amines (hexadecylamine and dodecylamine) as a solvent. Beyond their role as solvent, the amines also act as a template, directing the growth of discrete units with a one-dimensional multilayer tubular nanostructure. These new materials, which broaden the family of amine-stabilized gallium chalcogenides, can be tentatively classified as direct large band gap semiconductors. Their preliminary performance as active material for electrodes in lithium ion batteries has also been tested, demonstrating great potential in energy storage field even without optimization.We describe the soft chemistry synthesis of amine-templated gallium chalcogenide nanotubes through the reaction of gallium(iii) acetylacetonate and the chalcogen (sulfur, selenium) using a mixture of long-chain amines (hexadecylamine and dodecylamine) as a solvent. Beyond their role as solvent, the amines also act as a template, directing the growth of discrete units with a one-dimensional multilayer tubular nanostructure. These new materials, which broaden the family of amine-stabilized gallium chalcogenides, can be tentatively classified as direct large band gap semiconductors. Their preliminary performance as active material for electrodes in lithium ion batteries has also been tested, demonstrating great potential in energy storage field even without optimization. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr01663d

  18. Synthesis and Investigation of Millimeter-Scale Vertically Aligned Boron Nitride Nanotube Arrays

    Science.gov (United States)

    Tay, Roland; Li, Hongling; Tsang, Siu Hon; Jing, Lin; Tan, Dunlin; Teo, Edwin Hang Tong

    Boron nitride nanotubes (BNNTs) have shown potential in a wide range of applications due to their superior properties such as exceptionally high mechanical strength, excellent chemical and thermal stabilities. However, previously reported methods to date only produced BNNTs with limited length/density and insufficient yield at high temperatures. Here we present a facile and effective two-step synthesis route involving template-assisted chemical vapor deposition at a relatively low temperature of 900 degree C and subsequent annealing process to fabricate vertically aligned (VA) BN coated carbon nanotube (VA-BN/CNT) and VA-BNNT arrays. By using this method, we achieve the longest VA-BN/CNTs and VA-BNNTs to date with lengths of over millimeters (exceeding two orders of magnitude longer than the previously reported length of VA-BNNTs). In addition, the morphology, chemical composition and microstructure of the resulting products, as well as the mechanism of coating process are systematically investigated. This versatile BN coating technique and the synthesis of millimeter-scale BN/CNT and BNNT arrays pave a way for new applications especially where the aligned geometry of the NTs is essential such as for field-emission, interconnects and thermal management.

  19. Properties, synthesis, and growth mechanisms of carbon nanotubes with special focus on thermal chemical vapor deposition.

    Science.gov (United States)

    Nessim, Gilbert D

    2010-08-01

    Carbon nanotubes (CNTs) have been extensively investigated in the last decade because their superior properties could benefit many applications. However, CNTs have not yet made a major leap into industry, especially for electronic devices, because of fabrication challenges. This review provides an overview of state-of-the-art of CNT synthesis techniques and illustrates their major technical difficulties. It also charts possible in situ analyses and new reactor designs that might enable commercialization. After a brief description of the CNT properties and of the various techniques used to synthesize substrate-free CNTs, the bulk of this review analyzes chemical vapor deposition (CVD). This technique receives special attention since it allows CNTs to be grown in predefined locations, provides a certain degree of control of the types of CNTs grown, and may have the highest chance to succeed commercially. Understanding the primary growth mechanisms at play during CVD is critical for controlling the properties of the CNTs grown and remains the major hurdle to overcome. Various factors that influence CNT growth receive a special focus: choice of catalyst and substrate materials, source gases, and process parameters. This review illustrates important considerations for in situ characterization and new reactor designs that may enable researchers to better understand the physical growth mechanisms and to optimize the synthesis of CNTs, thus contributing to make carbon nanotubes a manufacturing reality.

  20. 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.

  1. The catalystic asymmetric synthesis of optically active epoxy ketones

    NARCIS (Netherlands)

    Marsman, Bertha Gerda

    1981-01-01

    In this thesis the use of catalytic asymmetric synthesis to prepare optically active epoxy ketones is described. This means that the auxiliary chirality, necessary to obtain an optically active product, is added in a catalytic quantity . In principle this is a very efficient way to make opticlly

  2. Three-dimensional ultrashort optical Airy beams in an inhomogeneous medium with carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Zhukov, Alexander V., E-mail: alex.zhukov@outlook.sg [Singapore University of Technology & Design, 8 Somapah Road, 487372 Singapore (Singapore); Bouffanais, Roland [Singapore University of Technology & Design, 8 Somapah Road, 487372 Singapore (Singapore); Belonenko, Mikhail B. [Laboratory of Nanotechnology, Volgograd Institute of Business, 400048 Volgograd (Russian Federation); Volgograd State University, 400062 Volgograd (Russian Federation); Dvuzhilov, Ilya S. [Volgograd State University, 400062 Volgograd (Russian Federation)

    2017-03-11

    In this Letter, we consider the problem of the dynamics of propagation of three-dimensional optical pulses (a.k.a. light bullets) with an Airy profile through a heterogeneous environment of carbon nanotubes. We show numerically that such beams exhibit sustained and stable propagation. Moreover, we demonstrate that by varying the density modulation period of the carbon nanotubes one can indirectly control the pulse velocity, which is a particularly valuable feature for the design and manufacturing of novel pulse delay devices. - Highlights: • Propagation of Airy pulses in CNTs with modulated density. • Light bullets propagate stably. • Influence of Airy parameter is revealed. • Modulation period results in an increase of the pulse velocity.

  3. Electro-optical memory of a nematic liquid crystal doped by multi-walled carbon nanotubes

    Directory of Open Access Journals (Sweden)

    L. Dolgov

    2012-10-01

    Full Text Available A pronounced irreversible electro-optical response (memory effect has been recently observed for nematic liquid crystal (LC EBBA doped by multi-walled carbon nanotubes (MWCNTs near the percolation threshold of the MWCNTs (0.02÷0.05 wt. %. It is caused by irreversible homeotropic-to-planar reorientation of LC in an electric field. This feature is explained by electro-hydrodynamically stimulated dispergation of MWCNTs in LC and by the formation of a percolation MWCNT network which acts as a spatially distributed surface stabilizing the planar state of the LC. This mechanism is confirmed by the absence of memory in the EBBA/MWCNT composites, whose original structure is fixed by a polymer. The observed effect suggests new operation modes for the memory type and bistable LC devices, as well as a method for in situ dispergation of carbon nanotubes in LC cells.

  4. Growth, Structural and Optical Characterization of ZnO Nanotubes on Disposable-Flexible Paper Substrates by Low-Temperature Chemical Method

    Directory of Open Access Journals (Sweden)

    M. Y. Soomro

    2012-01-01

    Full Text Available We report the synthesis of vertically aligned ZnO nanotubes (NTs on paper substrates by low-temperature hydrothermal method. The growth of ZnO NTs on the paper substrate is discussed; further, the structural and optical properties are investigated by scanning electron microscope (SEM, transmission electron microscopy (TEM, X-ray diffraction (XRD, energy-dispersive X-ray spectroscopy (EDS, and cathodoluminescence (CL, and it was found that the ZnO NTs on paper substrate fulfill the structural and optical properties of ZnO NTs grown on other conventional substrates. This will be more beneficial in future usage of ZnO NTs in different fields and applications. Particularly, this approach opens the ways in research and development for high volume manufacturing of low-cost, flexible optoelectronics devices on disposable paper substrates and can be used in the future miniaturization trends.

  5. Strategic Functionalization of Single Walled Carbon Nanotubes to Manipulate Their Electronic and Optical Properties

    Science.gov (United States)

    Gifford, Brendan Joel

    Single-walled carbon nanotubes (SWCNTs) are unique materials that exhibit chirality-specific properties due to their one-dimensional confinement. As a result, they are explored for a wide range of applications including single-photon sources in communications devices. Despite progress in this area, SWCNTs still suffer from a relatively narrow range of energies of emission features that fall short of the 1500 nm desired for long-distance lossless data transfer. One approach that is frequently used to resolve this involves chemical functionalization with aryl groups. However, this approach is met with a number of fundamental issues. First, chirality-specific SWCNTs must be acquired for subsequent functionalization. Synthesis of such samples has thus far eluded experimental efforts. As such, post-synthetic non-covalent functionalization is required to break bundles and create disperse SWCNTs that can undergo further separation, processing, and functionalization. Second, a number of low-energy emission features are introduced upon functionalization across a 200 nm range. The origin of such diverse emission features remains unknown. The research presented here focuses on computationally addressing these issues. A series of polyfluorene polymers possessing sidechains of varying length are explored using molecular mechanics to determine the impact of alkyl sidechains on SWCNT-conjugated polymer interaction strength and morphology. Additionally, density functional theory (DFT) and linear-response time-dependent DFT (TDDFT) are used to explore the effect of functionalization on emission features. A prerequisite to these calculations involves constructing finite-length SWCNT systems with similar electronic structure to their infinite counterparts: a methodological approach for the formation of such systems is presented. The optical features for aryl-functionalized SWCNTs are then explored. It is shown that the predominant effect on the energies of emission features involves

  6. Synthesis of Carbon Nanotubes and Nanospheres from Coconut Fibre and the Role of Synthesis Temperature on Their Growth

    Science.gov (United States)

    Adewumi, Gloria A.; Inambao, Freddie; Eloka-Eboka, Andrew; Revaprasadu, Neerish

    2018-04-01

    Carbon nanotubes (CNT) and carbon nanospheres were successfully synthesized from coconut fibre-activated carbon. The biomass was first carbonized then physically activated, followed by treatment using ethanol vapor at 700°C to 1100°C at 100°C intervals. The effect of synthesis temperature on the formation of the nanomaterials was studied using scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive x-ray spectrometry, x-ray diffraction (XRD), Fourier transform infrared microscopy (FTIR) and thermogravimetric analysis. SEM analysis revealed that nanospheres were formed at higher temperatures of 1000°C and 1100°C, while lower temperatures of 800°C and 900°C favored the growth of CNT. At 700°C, however, no tubes or spheres were formed. TEM and FTIR were used to observe spectral features, such as the peak positions, intensity and bandwidth, which are linked to some structural properties of the samples investigated. All these observations provided facts on the nanosphere and nanotube dimensions, vibrational modes and the degree of purity of the obtained samples. The TEM results show spheres of diameter in the range 50 nm to 250 nm while the tubes had diameters between 50 nm to 100 nm. XRD analysis reveals the materials synthesized are amorphous in nature with a hexagonal graphite structure.

  7. Morphology-Controlled Synthesis of Hematite Nanocrystals and Their Optical, Magnetic and Electrochemical Performance

    Science.gov (United States)

    Li, Bangquan; Sun, Qian; Fan, Hongsheng; Cheng, Ming; Shan, Aixian; Cui, Yimin; Wang, Rongming

    2018-01-01

    A series of α-Fe2O3 nanocrystals (NCs) with fascinating morphologies, such as hollow nanoolives, nanotubes, nanospindles, and nanoplates, were prepared through a simple template-free hydrothermal synthesis process. The results showed that the morphologies could be easily controlled by SO42− and H2PO4−. Physical property analysis showed that the α-Fe2O3 NCs exhibited shape- and size-dependent ferromagnetic and optical behaviors. The absorption band peak of the α-Fe2O3 NCs could be tuned from 320 to 610 nm. Furthermore, when applied as electrode material for supercapacitor, the hollow olive-structure exhibited the highest capacitance (285.9 F·g−1) and an excellent long-term cycling stability (93% after 3000 cycles), indicating that it could serve as a candidate electrode material for a supercapacitor. PMID:29342929

  8. Linear optical response of carbon nanotubes under axial magnetic field

    Science.gov (United States)

    Moradian, Rostam; Chegel, Raad; Behzad, Somayeh

    2010-04-01

    We considered single walled carbon naotubes (SWCNTs) as real three dimensional (3D) systems in a cylindrical coordinate. The optical matrix elements and linear susceptibility, χ(ω), in the tight binding approximation in terms of one-dimensional wave vector, kz and subband index, l are calculated. In an external axial magnetic field optical frequency dependence of linear susceptibility are investigated. We found that axial magnetic field has two effects on the imaginary part of the linear susceptibility spectrum, in agreement with experimental results. The first effect is broadening and the second, splitting. Also we found that for all metallic zigzag and armchair SWCNTs, the axial magnetic field leads to the creation of a peak with energy less than 1.5 eV, contrary to what is observed in the absence of a magnetic field.

  9. Manipulation and light-induced agglomeration of carbon nanotubes through optical trapping of attached silver nanoparticles

    International Nuclear Information System (INIS)

    Shi Chao; Zhang Yi; Gu, Claire; Seballos, Leo; Zhang, Jin Z

    2008-01-01

    A simple experimental method has been demonstrated for manipulating multi-walled carbon nanotube (MWCNT) bundles through the optical trapping of attached silver nanoparticles (SNPs). In our experiments, without the SNPs, the MWCNTs cannot be trapped due to their irregular shapes and large aspect ratio. However, when mixed with SNPs, the MWCNTs can be successfully trapped along with the SNPs using a TEM 00 mode laser at 532 nm. This is attributed to the optical trapping of the SNPs and attractive interaction or binding between the SNPs and MWCNTs due to electrostatic and van der Waals forces. Therefore, optical manipulation of MWCNT bundles is achieved through the manipulation of the attached silver nanoparticles/aggregates. In addition, we have observed the phenomenon of light-induced further agglomeration of SNPs/MWCNTs which could potentially be exploited for fabricating patterned MWCNT films for future nanoscale devices and other applications

  10. Polyaniline/carbon nanotube/CdS quantum dot composites with enhanced optical and electrical properties

    Science.gov (United States)

    Goswami, Mrinmoy; Ghosh, Ranajit; Maruyama, Takahiro; Meikap, Ajit Kumar

    2016-02-01

    A new kind of polyaniline/carbon nanotube/CdS quantum dot composites have been developed via in-situ polymerization of aniline monomer in the presence of dispersed CdS quantum dots (size: 2.7-4.8 nm) and multi-walled carbon nanotubes (CNT), which exhibits enhanced optical and electrical properties. The existences of 1st order, 2nd order, and 3rd order longitudinal optical phonon modes, strongly indicate the high quality of synthesized CdS quantum dots. The occurrence of red shift of free exciton energy in photoluminescence is due to size dependent quantum confinement effect of CdS. The conductivity of the composites (for example PANI/CNT/CdS (2 wt.% CdS)) is increased by about 7 of magnitude compared to that of pure PANI indicating a charge transfer between CNT and polymer via CdS quantum dots. This advanced material has a great potential for high-performance of electro-optical applications.

  11. Analytic Study of Optical, Electro-optical and Magnetooptical Properties of Cabon Nanotubes

    DEFF Research Database (Denmark)

    Zarifi, Abbas

    Multi-wall and single-wall carbon nanotubes (SWCNs) have attracted considerable amount of attention in nanoscience due to their unique physical properties and great potential for nanotechnology applications. The SWCNs are more fundamental and had been the basis for a large body of theoretical...

  12. Recent Trends in the Microwave-Assisted Synthesis of Metal Oxide Nanoparticles Supported on Carbon Nanotubes and Their Applications

    Directory of Open Access Journals (Sweden)

    Sarah C. Motshekga

    2012-01-01

    Full Text Available The study of coating carbon nanotubes with metal/oxides nanoparticles is now becoming a promising and challenging area of research. To optimize the use of carbon nanotubes in various applications, it is necessary to attach functional groups or other nanostructures to their surface. The combination of the distinctive properties of carbon nanotubes and metal/oxides is expected to be applied in field emission displays, nanoelectronic devices, novel catalysts, and polymer or ceramic reinforcement. The synthesis of these composites is still largely based on conventional techniques, such as wet impregnation followed by chemical reduction of the metal nanoparticle precursors. These techniques based on thermal heating can be time consuming and often lack control of particle size and morphology. Hence, there is interest in microwave technology recently, where using microwaves represents an alternative way of power input into chemical reactions through dielectric heating. This paper covers the synthesis and applications of carbon-nanotube-coated metal/oxides nanoparticles prepared by a microwave-assisted method. The reviewed studies show that the microwave-assisted synthesis of the composites allows processes to be completed within a shorter reaction time with uniform and well-dispersed nanoparticle formation.

  13. Stable optical soliton in the ring-cavity fiber system with carbon nanotube as saturable absorber

    Science.gov (United States)

    Li, Bang-Qing; Ma, Yu-Lan; Yang, Tie-Mei

    2018-01-01

    Main attention focuses on the theoretical study of the ring-cavity fiber laser system with carbon nanotubes (CNT) as saturable absorber (SA). The system is modelled as a non-standard Schrödinger equation with the coefficients blended real and imaginary numbers. New stable exact soliton solution is constructed by the bilinear transformation method for the system. The influences of the key parameters related to CNTs and SA on the optical pulse soliton are discussed in simulation. The soliton amplitude and phase can be tuned by choosing suitable parameters.

  14. Extremely short optical pulse in a system of nanotubes with adsorbed hydrogen

    International Nuclear Information System (INIS)

    Belonenko, Mikhail B.; Popov, Alexander S.; Lebedev, Nikolay G.; Pak, Anastasia V.; Zhukov, Alexander V.

    2011-01-01

    In this Letter we address the system of carbon nanotubes with adsorbed hydrogen, which is a problem of particular practical importance. Based on the periodic Anderson model we describe the electronic subsystem in such a system, so that employing the method of Green functions allowed us to obtain the dispersion law for electrons. In the low-temperature limit we investigated a joint dynamics of electrons and electromagnetic field. The effective equation, which describes the propagation of ultrashort optical pulses, has been derived. We analyze the solutions of this equation and their dependence on the parameters of the problem for a two-dimensional CNT system.

  15. Illuminating the future of silicon photonics: optical coupling of carbon nanotubes to microrings

    International Nuclear Information System (INIS)

    Kato, Y K

    2015-01-01

    Advances in carbon nanotube material quality and processing techniques have led to an increased interest in nanotube photonics. In particular, emission in the telecommunication wavelengths makes nanotubes compatible with silicon photonics. Noury et al (2014 Nanotechnology 25 215201) have reported on carbon nanotube photoluminescence coupled to silicon microring resonators, underscoring the advantage of combining carbon nanotube emitters with silicon photonics. Their results open up the possibility of using nanotubes in other waveguide-based devices, taking advantage of well-established technologies. (viewpoint)

  16. Multifractal characterization of single wall carbon nanotube thin films surface upon exposure to optical parametric oscillator laser irradiation

    International Nuclear Information System (INIS)

    Ţălu, Ştefan; Marković, Zoran; Stach, Sebastian; Todorović Marković, B.; Ţălu, Mihai

    2014-01-01

    This study presents a multifractal approach, obtained with atomic force microscopy analysis, to characterize the structural evolution of single wall carbon nanotube thin films upon exposure to optical parametric oscillator laser irradiation at wavelength of 430 nm. Microstructure and morphological changes of carbon nanotube films deposited on different substrates (mica and TGX grating) were recorded by atomic force microscope. A detailed methodology for surface multifractal characterization, which may be applied for atomic force microscopy data, was presented. Multifractal analysis of surface roughness revealed that carbon nanotube films surface has a multifractal geometry at various magnifications. The generalized dimension D q and the singularity spectrum f(α) provided quantitative values that characterize the local scale properties of carbon nanotube films surface morphology at nanometer scale. Multifractal analysis provides different yet complementary information to that offered by traditional surface statistical parameters.

  17. Spontaneous and controlled-diameter synthesis of single-walled and few-walled carbon nanotubes

    Science.gov (United States)

    Inoue, Shuhei; Lojindarat, Supanat; Kawamoto, Takahiro; Matsumura, Yukihiko; Charinpanitkul, Tawatchai

    2018-05-01

    In this study, we explored the spontaneous and controlled-diameter growth of carbon nanotubes. We evaluated the effects of catalyst density, reduction time, and a number of catalyst coating on the substrate (for multi-walled carbon nanotubes) on the diameter of single-walled carbon nanotubes and the number of layers in few-walled carbon nanotubes. Increasing the catalyst density and reduction time increased the diameters of the carbon nanotubes, with the average diameter increasing from 1.05 nm to 1.86 nm for single-walled carbon nanotubes. Finally, we succeeded in synthesizing a significant double-walled carbon nanotube population of 24%.

  18. Synthesis and characterization of cobaltite nanotubes for solid-oxide fuel cell cathodes

    Energy Technology Data Exchange (ETDEWEB)

    Napolitano, F; Baque, L; Troiani, H; Granada, M; Serquis, A, E-mail: aserquis@cab.cnea.gov.a [Instituto Balseiro-Centro Atomico Bariloche and CONICET, San Carlos de Bariloche (Argentina)

    2009-05-01

    La{sub 1-x}Sr{sub x}Co{sub 1-y}FeyO{sub 3-d}elta oxides are good candidates for solid oxide fuel cell (SOFC) cathodes because these materials present high ionic and electronic conductivity, and compatibility with Cerium Gadolinium Oxide (CGO) electrolytes allowing a lower operation temperature. In this work, we report the synthesis of La{sub 0.4}Sr{sub 0.6}Co{sub 0.8}Fe{sub 0.2}O{sub 3-d}elta (LSCF) nanotubes prepared by a porous polycarbonate membrane approach, obtaining different microstructures depending on sintering conditions. The structure and morphology of the nanotubes and deposited films were characterized by X-ray diffraction, transmission and scanning microscopy. Finally, we obtained nanostructured films of vertically aligned LSCF tubes deposited over the whole surface of CGO pellets with diameter up to 2.5cm in a direct and single step process.

  19. The pulmonary inflammatory response to multiwalled carbon nanotubes is influenced by gender and glutathione synthesis

    Directory of Open Access Journals (Sweden)

    Megan M. Cartwright

    2016-10-01

    Full Text Available Inhalation of multiwalled carbon nanotubes (MWCNTs during their manufacture or incorporation into various commercial products may cause lung inflammation, fibrosis, and oxidative stress in exposed workers. Some workers may be more susceptible to these effects because of differences in their ability to synthesize the major antioxidant and immune system modulator glutathione (GSH. Accordingly, in this study we examined the influence of GSH synthesis and gender on MWCNT-induced lung inflammation in C57BL/6 mice. GSH synthesis was impaired through genetic manipulation of Gclm, the modifier subunit of glutamate cysteine ligase, the rate-limiting enzyme in GSH synthesis. Twenty-four hours after aspirating 25 µg of MWCNTs, all male mice developed neutrophilia in their lungs, regardless of Gclm genotype. However, female mice with moderate (Gclm heterozygous and severe (Gclm null GSH deficiencies developed significantly less neutrophilia. We found no indications of MWCNT-induced oxidative stress as reflected in the GSH content of lung tissue and epithelial lining fluid, 3-nitrotyrosine formation, or altered mRNA or protein expression of several redox-responsive enzymes. Our results indicate that GSH-deficient female mice are rendered uniquely susceptible to an attenuated neutrophil response. If the same effects occur in humans, GSH-deficient women manufacturing MWCNTs may be at greater risk for impaired neutrophil-dependent clearance of MWCNTs from the lung. In contrast, men may have effective neutrophil-dependent clearance, but may be at risk for lung neutrophilia regardless of their GSH levels.

  20. Stable synthesis of few-layered boron nitride nanotubes by anodic arc discharge.

    Science.gov (United States)

    Yeh, Yao-Wen; Raitses, Yevgeny; Koel, Bruce E; Yao, Nan

    2017-06-08

    Boron nitride nanotubes (BNNTs) were successfully synthesized by a dc arc discharge using a boron-rich anode as synthesis feedstock in a nitrogen gas environment at near atmospheric pressure. The synthesis was achieved independent of the cathode material suggesting that under such conditions the arc operates in so-called anodic mode with the anode material being consumed by evaporation due to the arc heating. To sustain the arc current by thermionic electron emission, the cathode has to be at sufficiently high temperature, which for a typical arc current density of ~100 A/cm 2 , is above the boron melting point (2350 K). With both electrodes made from the same boron-rich alloy, we found that the arc operation unstable due to frequent sticking between two molten electrodes and formation of molten droplets. Stable and reliable arc operation and arc synthesis were achieved with the boron-rich anode and the cathode made from a refractory metal which has a melting temperature above the melting point of boron. Ex-situ characterization of synthesized BNNTs with electron microscopy and Raman spectroscopy revealed that independent of the cathode material, the tubes are primarily single and double walled. The results also show evidence of root-growth of BNNTs produced in the arc discharge.

  1. Controllable synthesis of spongy carbon nanotube blocks with tunable macro- and microstructures

    International Nuclear Information System (INIS)

    Gui Xuchun; Lin Zhiqiang; Zeng Zhiping; Tang Zikang; Wang Kunlin; Wu Dehai

    2013-01-01

    Macroscopic carbon nanotubes (CNTs) with uniform structures are in great demand for use in composites and environmental materials. Here we demonstrate the controlled synthesis of spongy CNT blocks with isotropic properties and flexible, freestanding structures. The formation mechanism of the isotropic CNT sponges is discussed, based on its open-ended structure and initial formation in the vapor phase. The microstructure of the CNT sponges can be tuned by changing the flow rate of the carrier gas, resulting in CNT sponges with diameters ranging from 30.2 to 47.8 nm and wall thicknesses from 7 to 16 nm. The bulk density (5–25 mg cm −3 ), mechanical strength of the CNT sponges, and filling rate of ferromagnetic catalyst in the CNT sponges can also be modulated by controlling the supply rate of the carbon source, suggesting potential applications in mechanical energy absorption and environmental materials. (paper)

  2. 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.

  3. Synthesis and Magnetic Properties of Maghemite (γ-Fe2O3 Short-Nanotubes

    Directory of Open Access Journals (Sweden)

    Xiao XH

    2010-01-01

    Full Text Available Abstract We report a rational synthesis of maghemite (γ-Fe2O3 short-nanotubes (SNTs by a convenient hydrothermal method and subsequent annealing process. The structure, shape, and magnetic properties of the SNTs were investigated. Room-temperature and low-temperature magnetic measurements show that the as-fabricated γ-Fe2O3 SNTs are ferromagnetic, and its coercivity is nonzero when the temperature above blocking temperature (TB. The hysteresis loop was operated to show that the magnetic properties of γ-Fe2O3 SNTs are strongly influenced by the morphology of the crystal. The unique magnetic behaviors were interpreted by the competition of the demagnetization energy of quasi-one-dimensional nanostructures and the magnetocrystalline anisotropy energy of particles in SNTs.

  4. The Synthesis of Peculiar Structure of Springlike Multiwall Carbon Nanofibers/Nanotubes via Mechanothermal Method

    Directory of Open Access Journals (Sweden)

    Sahebali Manafi

    2012-01-01

    Full Text Available Mechanothermal (MT method is one of the methods used for large-scale production of carbon nanotubes/nanofibers. The different peculiar morphologies of carbon allotropes are introduced with an extraordinary structure for the first time by MT method. In this paper, the influence of milling time and annealing temperature on the crystallinity and morphology of the synthesized nanopowders was investigated. Surprisingly, in this investigation, we report the synthesis of springlike multiwalled carbon nanofibers (S-MWCNFs by a two-step annealing of milled graphite in an Ar atmosphere. On the other hand, the MT method could be used for the preparation of suitable structures with applications in nanocomposite materials, which is an important task in the era of nanotechnology.

  5. Simple Microwave-Assisted Synthesis of Carbon Nanotubes Using Polyethylene as Carbon Precursor

    Directory of Open Access Journals (Sweden)

    N. Kure

    2017-01-01

    Full Text Available In this work, a quick and effective method to synthesize carbon nanotubes (CNTs is reported; a commercial microwave oven of 600 W at 2.45 GHz was utilized to synthesize CNTs from plasma catalytic decomposition of polyethylene. Polyethylene and silicon substrate coated with iron (III nitrate were placed in the reaction chamber to form the synthesis stock. The CNTs were synthesized at 750°C under atmospheric pressure of 0.81 mbar. Raman spectroscopy and field emission scanning electron microscope revealed the quality and entangled bundles of mixed CNTs from which the diameters of the CNTs were calculated to be between 1.03 and 25.00 nm. High resolution transmission electron microscope further showed that the CNTs obtained by this method are graphitized. Energy dispersive X-ray analysis and thermogravimetric analysis revealed above 98% carbon purity.

  6. Synthesis and analytical applications of molecularly imprinted polymers on the surface of carbon nanotubes: a review

    International Nuclear Information System (INIS)

    Dai, Hao; Xiao, Deli; Li, Hui; Yuan, Danhua; Zhang, Chan; He, Hua

    2015-01-01

    This review (with 142 references) summarize the state of the art in molecularly imprinting technology as applied to the surface of carbon nanotubes (CNTs) which result in so-called CNTs-MIPs. These nanomaterials offer a remedy to the flaws of traditional MIPs, such as poor site accessibility for templates, slow mass transfer and template leakage. They also are flexible in that different materials can be integrated with CNTs. Given the advantages of using CNT-MIPs, this technology has experienced rapid expansion, not the least because CNT-MIPs can be produced at low cost and by a variety of synthetic approaches. We summarize methods of, and recent advances in the synthesis of CNT-MIPs, and then highlight some representative applications. We also comment on their potential future developments and research directions. (author)

  7. Immobilised carbon nanotubes as carrier for Co-Fischer-Tropsch synthesis catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Thiessen, J.; Rose, A.; Kiendl, I.; Jess, A. [Bayreuth Univ. (Germany). Dept. of Chemical Engineering; Curulla-Ferre, D. [Total S.A., Gas and Power, Paris La Defense (France)

    2011-07-01

    A possibility to immobilise carbon nanotubes (CNT) to make them applicable in a technical scale fixed bed reactor is studied. The approach to fabricate millimetre scale composites containing CNT presented in this work is to confine the nano-carbon in macro porous ceramic particles. Thus CNT were grown on the inner surface of silica and alumina pellets and spheres, respectively. Cobalt nano particles were successfully deposited on the carbon surface inside the two types of ceramic carriers and the systems were tested in Fischer - Tropsch synthesis (FTS). The cobalt mass related activity of these novel catalysts is similar to a conventional system. The selectivities of the Co/CNT/ceramic composites were compared with non supported CNT and carbon nanofibres (CNF). (orig.)

  8. Amine functionalized TiO2-carbon nanotube composite: synthesis, characterization and application to glucose biosensing

    Science.gov (United States)

    Tasviri, Mahboubeh; Rafiee-Pour, Hossain-Ali; Ghourchian, Hedayatollah; Gholami, Mohammad Reza

    2011-12-01

    The synthesis of amine functionalized TiO2-coated multiwalled carbon nanotubes (NH2-TiO2-CNTs) using sol-gel method was investigated. The synthesized nanocomposite was characterized with XRD, FTIR spectroscopy, BET test and SEM imaging. The results demonstrated a unique nanostructure with no destruction of the CNTs' shape. In addition, the presence of amine groups on the composite surface was confirmed by FTIR. This nanocomposite was used for one-step immobilization of glucose oxidase (GOx) to sense glucose. The result of cyclic voltammetry showed a pair of well-defined and quasi-reversible peaks for direct electron transfer of GOx in the absence of glucose. Also, the result of electrochemical impedance spectroscopy indicated that GOx was successfully immobilized on the surface of NH2-TiO2-CNTs. Furthermore, good amperometric response showed that immobilized GOx on the NH2-TiO2-CNTs exhibits exceptional bioelectrocatalytic activity toward glucose oxidation.

  9. Sol-gel synthesis of Bi{sub 3.25}La{sub 0.75}Ti{sub 3}O{sub 12} nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Wang Wen, E-mail: wangwen@hit.edu.cn [Institute for Advanced Ceramics, School of Materials Science and Engineering, Harbin Institute of Technology, No. 92 West Da-Zhi Street, Harbin 150001, Heilongjiang (China); Hua, Ke; Jiancun, Rao; Jinbiao, Feng; Ming, Feng; Dechang, Jia; Yu, Zhou [Institute for Advanced Ceramics, School of Materials Science and Engineering, Harbin Institute of Technology, No. 92 West Da-Zhi Street, Harbin 150001, Heilongjiang (China)

    2011-04-07

    Research highlights: > One-dimensional (1D) ferroelectrics have been successfully synthesized. The sol-gel template synthesis is a versatile and inexpensive technique for producing nanostructures, and particularly facilitates the fabrication of complex oxide nanotubes or nanowires. Compared with the synthesis of the general nanotubes such as carbon nanotubes with simple crystal structure, the synthesis of ferroelectric compound is difficult due to the multielement and the complex crystal structures of these ferroelectrics. Herein, we report the synthesis of one-dimensional BLT nanotubes on anodic alumina (AAO) templates by immersing a template membrane in sol without polymeric additive. - Abstract: Ferroelectric Bi{sub 3.25}La{sub 0.75}Ti{sub 3}O{sub 12} (BLT) nanotubes were synthesized by sol-gel technique using nanochannel porous anodic aluminum oxide (AAO) templates, and were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and high resolution transmission electron microscopy (HRTEM). BLT nanotubes with diameter of around 240 nm and the wall thickness of about 25 nm exhibited a single orthorhombic perovskite structure and highly preferential crystal growth along the [1 1 7] orientation, which have smooth wall morphologies and well-defined diameters corresponding to the diameter of the applied template. The formation mechanism of BLT nanotubes was discussed.

  10. On the optical properties of carbon nanotubes. Part I. A general formula for the dynamical optical conductivity

    Energy Technology Data Exchange (ETDEWEB)

    Rasmussen, Morten Grud, E-mail: morteng@math.aau.dk [Department of Mathematical Sciences, Aalborg University, Fredrik Bajers Vej 7G, 9220 Aalborg (Denmark); Ricaud, Benjamin, E-mail: benjamin.ricaud@epfl.ch [Laboratoire de Traitement des Signaux 2, École Polytechnique Fédérale de Lausanne, Lausanne, Vaud (Switzerland); Savoie, Baptiste, E-mail: baptiste.savoie@gmail.com [Dublin Institute for Advanced Studies, School of Theoretical Physics, 10 Burlington Road, Dublin 04 (Ireland)

    2016-02-15

    This paper is the first one in a series of two articles in which we revisit the optical properties of single-walled carbon nanotubes (SWNTs). Produced by rolling up a graphene sheet, SWNTs owe their intriguing properties to their cylindrical quasi-one-dimensional (quasi-1D) structure (the ratio length/radius is experimentally of order of 10{sup 3}). We model SWNT by circular cylinders of small diameters on the surface of which the conduction electron gas is confined by the electric field generated by the fixed carbon ions. The pair-interaction potential considered is the 3D Coulomb potential restricted to the cylinder. To reflect the quasi-1D structure, we introduce a 1D effective many-body Hamiltonian which is the starting-point of our analysis. To investigate the optical properties, we consider a perturbation by a uniform time-dependent electric field modeling an incident light beam along the longitudinal direction. By using Kubo’s method, we derive within the linear response theory an asymptotic expansion in the low-temperature regime for the dynamical optical conductivity at fixed density of particles. The leading term only involves the eigenvalues and associated eigenfunctions of the (unperturbed) 1D effective many-body Hamiltonian and allows us to account for the sharp peaks observed in the optical absorption spectrum of SWNT.

  11. Electrochemical synthesis of 1D core-shell Si/TiO2 nanotubes for lithium ion batteries

    Science.gov (United States)

    Kowalski, Damian; Mallet, Jeremy; Thomas, Shibin; Nemaga, Abirdu Woreka; Michel, Jean; Guery, Claude; Molinari, Michael; Morcrette, Mathieu

    2017-09-01

    Silicon negative electrode for lithium ion battery was designed in the form of self-organized 1D core-shell nanotubes to overcome shortcomings linked to silicon volume expansion upon lithiation/delithiation typically occurring with Si nanoparticles. The negative electrode was formed on TiO2 nanotubes in two step electrochemical synthesis by means of anodizing of titanium and electrodeposition of silicon using ionic liquid electrolytes. Remarkably, it was found that the silicon grows perpendicularly to the z-axis of nanotube and therefore its thickness can be precisely controlled by the charge passed in the electrochemical protocol. Deposited silicon creates a continuous Si network on TiO2 nanotubes without grain boundaries and particle-particle interfaces, defining its electrochemical characteristics under battery testing. In the core-shell system the titania nanotube play a role of volume expansion stabilizer framework holding the nanostructured silicon upon lithiation/delithiation. The nature of Si shell and presence of titania core determine stable performance as negative electrode tested in half cell of CR2032 coin cell battery.

  12. 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.

  13. 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.

  14. Synthesis and characterization of RuO(2)/poly(3,4-ethylenedioxythiophene) composite nanotubes for supercapacitors.

    Science.gov (United States)

    Liu, Ran; Duay, Jonathon; Lane, Timothy; Bok Lee, Sang

    2010-05-07

    We report the synthesis of composite RuO(2)/poly(3,4-ethylenedioxythiophene) (PEDOT) nanotubes with high specific capacitance and fast charging/discharging capability as well as their potential application as electrode materials for a high-energy and high-power supercapacitor. RuO(2)/PEDOT nanotubes were synthesized in a porous alumina membrane by a step-wise electrochemical deposition method, and their structures were characterized using electron microscopy. Cyclic voltammetry was used to qualitatively characterize the capacitive properties of the composite RuO(2)/PEDOT nanotubes. Their specific capacitance, energy density and power density were evaluated by galvanostatic charge/discharge cycles at various current densities. The pseudocapacitance behavior of these composite nanotubes originates from ion diffusion during the simultaneous and parallel redox processes of RuO(2) and PEDOT. We show that the energy density (specific capacitance) of PEDOT nanotubes can be remarkably enhanced by electrodepositing RuO(2) into their porous walls and onto their rough internal surfaces. The flexible PEDOT prevents the RuO(2) from breaking and detaching from the current collector while the rigid RuO(2) keeps the PEDOT nanotubes from collapsing and aggregating. The composite RuO(2)/PEDOT nanotube can reach a high power density of 20 kW kg(-1) while maintaining 80% energy density (28 Wh kg(-1)) of its maximum value. This high power capability is attributed to the fast charge/discharge of nanotubular structures: hollow nanotubes allow counter-ions to readily penetrate into the composite material and access their internal surfaces, while a thin wall provides a short diffusion distance to facilitate ion transport. The high energy density originates from the RuO(2), which can store high electrical/electrochemical energy intrinsically. The high specific capacitance (1217 F g(-1)) which is contributed by the RuO(2) in the composite RuO(2)/PEDOT nanotube is realized because of the high

  15. Synthesis and photocatalytic activity of Ce-doped TiO2 and TiO2 nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Arruda, L.B.; Pereira, E.A.; Paula, F.R.; Lisboa Filho, P.N. [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), SP (Brazil)

    2016-07-01

    Full text: One-dimensional nanostructures have been intensively studied, from the point of view of their synthesis and mechanisms of formation, as well as their applications in photonics, solar energy conversion, environmental and photocatalysis, since their properties due high surface area, electrical conductivity and light dispersion effects. Titanium dioxide (TiO2) nanoparticles have been demonstrated to be an effective multifunctional material especially when the particle size is less than 50 nm exhibit photoinduced activities that originate from the semiconductor band gap. TiO2 is semiconductor more used in photocatalysis, for this reason various properties have been thoroughly investigated in order to show that the photocatalytic activity and TiO2 reaction mechanism are influenced by structure, defects and impurities, surface morphology. and interfaces in addition to the concentration of dopants, such as rare-earth elements. Cerium ions, for example, vary between Ce4+ and Ce3 + oxidation state making the cerium oxide appear as CeO2 and Ce2O3 under oxidation and reduction conditions. These different electronic structures of Ce3+ (4f15d0) and Ce4+ (4f05d0) provide different catalytic and optical properties at the TiO2. In this work, samples of Ce-doped TiO2 and TiO2 were synthesized by alkali route, and its photocatalytic activity analyzed in order to create a relationship between the response obtained and the structure and morphology of each sample. Alkali route consists in submitting TiO2 (anatase) powder directly in medium of the NaOH (10M) and maintained at 120°C/20 hours by a glycerin bath with subsequent washed with water and HCl (0.1M) until reaching the desired pH. The synthesized samples were then studied by X-ray diffraction (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The photocatalytic decomposition of rhodamine B (Rh.B) it was performed under UV irradiation and visible light in air. For the obtained

  16. Synthesis and photocatalytic activity of Ce-doped TiO2 and TiO2 nanotubes

    International Nuclear Information System (INIS)

    Arruda, L.B.; Pereira, E.A.; Paula, F.R.; Lisboa Filho, P.N.

    2016-01-01

    Full text: One-dimensional nanostructures have been intensively studied, from the point of view of their synthesis and mechanisms of formation, as well as their applications in photonics, solar energy conversion, environmental and photocatalysis, since their properties due high surface area, electrical conductivity and light dispersion effects. Titanium dioxide (TiO2) nanoparticles have been demonstrated to be an effective multifunctional material especially when the particle size is less than 50 nm exhibit photoinduced activities that originate from the semiconductor band gap. TiO2 is semiconductor more used in photocatalysis, for this reason various properties have been thoroughly investigated in order to show that the photocatalytic activity and TiO2 reaction mechanism are influenced by structure, defects and impurities, surface morphology. and interfaces in addition to the concentration of dopants, such as rare-earth elements. Cerium ions, for example, vary between Ce4+ and Ce3 + oxidation state making the cerium oxide appear as CeO2 and Ce2O3 under oxidation and reduction conditions. These different electronic structures of Ce3+ (4f15d0) and Ce4+ (4f05d0) provide different catalytic and optical properties at the TiO2. In this work, samples of Ce-doped TiO2 and TiO2 were synthesized by alkali route, and its photocatalytic activity analyzed in order to create a relationship between the response obtained and the structure and morphology of each sample. Alkali route consists in submitting TiO2 (anatase) powder directly in medium of the NaOH (10M) and maintained at 120°C/20 hours by a glycerin bath with subsequent washed with water and HCl (0.1M) until reaching the desired pH. The synthesized samples were then studied by X-ray diffraction (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The photocatalytic decomposition of rhodamine B (Rh.B) it was performed under UV irradiation and visible light in air. For the obtained

  17. Synthesis, structural and optical properties of nanoparticles (Al, V ...

    Indian Academy of Sciences (India)

    The synthesis by the sol–gel method, structural and optical properties of ZnO, Zn0.99Al0.01O (AlZ),. Zn0.9V0.1O (VZ) ... drops of the resulting suspension containing the synthesized .... ZnO films on silicon substrate, they thought that this emis-.

  18. Synthesis and Photocatalytic Activity of Anatase TiO2 Nanoparticles-coated Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Xie Yi

    2009-01-01

    Full Text Available Abstract A simple and straightforward approach to prepare TiO2-coated carbon nanotubes (CNTs is presented. Anatase TiO2 nanoparticles (NPs with the average size ~8 nm were coated on CNTs from peroxo titanic acid (PTA precursor even at low temperature of 100 °C. We demonstrate the effects of CNTs/TiO2 molar ratio on the adsorption capability and photocatalytic efficiency under UV–visible irradiation. The samples showed not only good optical absorption in visible range, but also great adsorption capacity for methyl orange (MO dye molecules. These properties facilitated the great enhancement of photocatalytic activity of TiO2 NPs-coated CNTs photocatalysts. The TiO2 NPs-coated CNTs exhibited 2.45 times higher photocatalytic activity for MO degradation than that of pure TiO2.

  19. Synthesis and Characterizations of Poly(3-hexylthiophene and Modified Carbon Nanotube Composites

    Directory of Open Access Journals (Sweden)

    Mohammad Rezaul Karim

    2012-01-01

    Full Text Available Poly(3-hexylthiophene and modified (functionalized and silanized multiwall carbon nanotube (MWNT nanocomposites have been prepared through in situ polymerization process in chloroform medium with FeCl3 oxidant at room temperature. The composites are characterized through Fourier transfer infrared spectroscopy (FT-IR, Raman, and X-ray diffraction (XRD measurements to probe the nature of interaction between the moieties. Optical properties of the composites are measured from ultraviolet-visible (UV-Vis and photoluminescence (PL spectroscopy. Conductivity of the composites is followed by four probe techniques to understand the conduction mechanism. The change (if any in C=C symmetric and antisymmetric stretching frequencies in FT-IR, the shift in G band frequencies in Raman, any alterations in λmax of UV-Vis, and PL spectroscopic measurements are monitored with modified MWNT loading in the polymer matrix.

  20. 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.

  1. Synthesis of polyetherimide / halloysite nanotubes (PEI/HNTs) based nanocomposite membrane towards hydrogen storage

    Science.gov (United States)

    Muthu, R. Naresh; Rajashabala, S.; Kannan, R.

    2018-04-01

    Even though hydrogen is considered as green and clean energy sources of future, the blooming of hydrogen economy mainly relies on the development of safe and efficient hydrogen storage medium. The present work is aimed at the synthesis and characterization of polyetherimide/acid treated halloysite nanotubes (PEI/A-HNTs) nanocomposite membranes for solid state hydrogen storage medium, where phase inversion technique was adopted for the synthesis of nanocomposite membrane. The synthesized PEI/A-HNTs nanocomposite membranes were characterized by XRD, FTIR, SEM, EDX, CHNS elemental analysis and TGA. Hydrogenation studies were performed using a Sievert's-like hydrogenation setup. The important conclusions arrived from the present work are the PEI/A-HNTs nanocomposite membranes have better performance with a maximum hydrogen storage capacity of 3.6 wt% at 100 °C than pristine PEI. The adsorbed hydrogen possesses the average binding energy of 0.31 eV which lies in the recommended range of US- DOE 2020 targets. Hence it is expected that the PEI/A-HNTs nanocomposite membranes may have bright extent in the scenario of hydrogen fuel cell applications.

  2. 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

  3. Preparation of Monodispersed Fe-Mo Nanoparticles as the Catalyst for CVD Synthesis of Carbon Nanotubes

    National Research Council Canada - National Science Library

    Li, Yan; Liu, Jie; Wang, Yongqian; Wang, Zhong L

    2001-01-01

    ...particles were systematically studied. The prepared nanoparticles were used as catalysts for single-walled carbon nanotube growth and the results indicate that there is an upper limit for the size of the catalyst particles to nucleate singlewalled carbon nanotubes.

  4. A bench arc-furnace facility for fullerene and single-wall nanotubes synthesis

    Directory of Open Access Journals (Sweden)

    Huber John G

    2001-01-01

    Full Text Available A metallic-sample arc-furnace was modified to synthesize fullerenes and nanotubes. The (reversible changes and the process for producing single-wall nanotubes (SWNTs are described.

  5. Aperture Synthesis Methods and Applications to Optical Astronomy

    CERN Document Server

    Saha, Swapan Kumar

    2011-01-01

    Over the years long baseline optical interferometry has slowly gained in importance and today it is a powerful tool. This timely book sets out to highlight the basic principles of long baseline optical interferometry. The book addresses the fundamentals of stellar interferometry with emphasis on aperture synthesis using an array of telescopes particularly at optical/IR wavelengths. It discusses the fundamentals of electromagnetic fields, wave optics, interference, diffraction, and imaging at length. There is a chapter dedicated to radio and intensity interferometry corroborating with basic mathematical steps. The basic principle of optical interferometry and its requirements, its limitations and the technical challenges it poses, are also covered in depth. Assisted by illustrations and footnotes, the book examines the basic tricks of the trade, current trends and methods, and it points to the potential of true interferometry both from the ground and space.

  6. Thermal transport of carbon nanotubes and graphene under optical and electrical heating measured by Raman spectroscopy

    Science.gov (United States)

    Hsu, I.-Kai

    This thesis presents systematic studies of thermal transport in individual single walled carbon nanotubes (SWCNTs) and graphene by optical and electrical approaches using Raman spectroscopy. In the work presented from Chapter 2 to Chapter 6, individual suspended CNTs are preferentially measured in order to explore their intrinsic thermal properties. Moreover, the Raman thermometry is developed to detect the temperature of the carbon nanotube (CNT). A parabolic temperature profile is observed in the suspended region of the CNT while a heating laser scans across it, providing a direct evidence of diffusive thermal transport in an individual suspended CNT. Based on the curvature of the temperature profile, we can solve for the ratio of thermal contact resistance to the thermal resistance of the CNT, which spans the range from 0.02 to 17. The influence of thermal contact resistance on the thermal transport in an individual suspended CNT is also studied. The Raman thermometry is carried out in the center of a CNT, while its contact length is successively shortened by an atomic force microscope (AFM) tip cutting technique. By investigating the dependence of the CNT temperature on its thermal contact length, the temperature of a CNT is found to increase dramatically as the contact length is made shorter. This work reveals the importance of manipulating the CNT thermal contact length when adopting CNT as a thermal management material. In using a focused laser to induce heating in a suspended CNT, one open question that remains unanswered is how many of the incident photons are absorbed by the CNT of interest. To address this question, micro-fabricated platinum thermometers, together with micro-Raman spectroscopy are used to quantify the optical absorption of an individual CNT. The absorbed power in the CNT is equal to the power detected by two thermometers at the end of the CNT. Our result shows that the optical absorption lies in the range between 0.03 to 0.44%. In

  7. 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.

  8. 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.

  9. The pulmonary inflammatory response to multiwalled carbon nanotubes is influenced by gender and glutathione synthesis.

    Science.gov (United States)

    Cartwright, Megan M; Schmuck, Stefanie C; Corredor, Charlie; Wang, Bingbing; Scoville, David K; Chisholm, Claire R; Wilkerson, Hui-Wen; Afsharinejad, Zahra; Bammler, Theodor K; Posner, Jonathan D; Shutthanandan, Vaithiyalingam; Baer, Donald R; Mitra, Somenath; Altemeier, William A; Kavanagh, Terrance J

    2016-10-01

    Inhalation of multiwalled carbon nanotubes (MWCNTs) during their manufacture or incorporation into various commercial products may cause lung inflammation, fibrosis, and oxidative stress in exposed workers. Some workers may be more susceptible to these effects because of differences in their ability to synthesize the major antioxidant and immune system modulator glutathione (GSH). Accordingly, in this study we examined the influence of GSH synthesis and gender on MWCNT-induced lung inflammation in C57BL/6 mice. GSH synthesis was impaired through genetic manipulation of Gclm, the modifier subunit of glutamate cysteine ligase, the rate-limiting enzyme in GSH synthesis. Twenty-four hours after aspirating 25µg of MWCNTs, all male mice developed neutrophilia in their lungs, regardless of Gclm genotype. However, female mice with moderate (Gclm heterozygous) and severe (Gclm null) GSH deficiencies developed significantly less neutrophilia. We found no indications of MWCNT-induced oxidative stress as reflected in the GSH content of lung tissue and epithelial lining fluid, 3-nitrotyrosine formation, or altered mRNA or protein expression of several redox-responsive enzymes. Our results indicate that GSH-deficient female mice are rendered uniquely susceptible to an attenuated neutrophil response. If the same effects occur in humans, GSH-deficient women manufacturing MWCNTs may be at greater risk for impaired neutrophil-dependent clearance of MWCNTs from the lung. In contrast, men may have effective neutrophil-dependent clearance, but may be at risk for lung neutrophilia regardless of their GSH levels. Copyright © 2016. Published by Elsevier B.V.

  10. Effects of antifreezes and bundled material on the stability and optical limiting in aqueous suspensions of carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Vlasov, Andrey Yu.; Venediktova, Anastasia V.; Sokolova, Ekaterina P. [Department of Chemistry, St. Petersburg State University, Universitetsky Pr. 26, St. Petersburg 198504 (Russian Federation); Videnichev, Dmitry A. [S.I. Vavilov State Optical Institute, Birzhevaya line 12, St. Petersburg 199034 (Russian Federation); St. Petersburg National Research University ITMO, Kronverksky pr. 49, St. Petersburg 197101 (Russian Federation); Lasers and Optical Systems JSC, Birzhevaya line 12, St. Petersburg 199034 (Russian Federation); Kislyakov, Ivan M. [S.I. Vavilov State Optical Institute, Birzhevaya line 12, St. Petersburg 199034 (Russian Federation); St. Petersburg National Research University ITMO, Kronverksky pr. 49, St. Petersburg 197101 (Russian Federation); Obraztsova, Elena D. [A.M. Prokhorov Institute of General Physics, Russian Academy of Sciences, Vavilov Str. 38, Moscow 119991 (Russian Federation)

    2012-12-15

    This work gives data on the stability of dispersions of single wall carbon nanotubes stabilized by sodium dodecylbenzenesulfonate in binary polar solvents ''water + antifreeze'' (glycerol, polyethyleneglycole) with eutectic compositions. The absorption spectra of the suspensions demonstrate no changes during 1-year storage with temperature spanning from -40 to +40 C. The systems provide relevant optical power limiting properties, the one with glycerol showing good resistance to optical bleaching effects. We also demonstrate that aqueous dispersions of nanotubes exhibit considerable enhancement of optical limiting parameters alongside an increase of the bundled material populace. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  11. Electronic structure and optical properties of boron nitride nanotube bundles from first principles

    Science.gov (United States)

    Behzad, Somayeh

    2015-06-01

    The electronic and optical properties of bundled armchair and zigzag boron nitride nanotubes (BNNTs) are investigated by using density functional theory. Owing to the inter-tube coupling, the dispersions along the tube axis and in the plane perpendicular to the tube axis of BNNT bundles are significantly varied, which are characterized by the decrease of band gap, the splitting of the doubly degenerated states, the expansions of valence and conduction bands. The calculated dielectric functions of the armchair and zigzag bundles are similar to that of the isolated tubes, except for the appearance of broadened peaks, small shifts of peak positions about 0.1 eV and increasing of peak intensities.

  12. Simultaneous synthesis of single-walled carbon nanotubes and graphene in a magnetically-enhanced arc plasma.

    Science.gov (United States)

    Li, Jian; Shashurin, Alexey; Kundrapu, Madhusudhan; Keidar, Michael

    2012-02-02

    Carbon nanostructures such as single-walled carbon nanotubes (SWCNT) and graphene attract a deluge of interest of scholars nowadays due to their very promising application for molecular sensors, field effect transistor and super thin and flexible electronic devices(1-4). Anodic arc discharge supported by the erosion of the anode material is one of the most practical and efficient methods, which can provide specific non-equilibrium processes and a high influx of carbon material to the developing structures at relatively higher temperature, and consequently the as-synthesized products have few structural defects and better crystallinity. To further improve the controllability and flexibility of the synthesis of carbon nanostructures in arc discharge, magnetic fields can be applied during the synthesis process according to the strong magnetic responses of arc plasmas. It was demonstrated that the magnetically-enhanced arc discharge can increase the average length of SWCNT (5), narrow the diameter distribution of metallic catalyst particles and carbon nanotubes (6), and change the ratio of metallic and semiconducting carbon nanotubes (7), as well as lead to graphene synthesis (8). Furthermore, it is worthwhile to remark that when we introduce a non-uniform magnetic field with the component normal to the current in arc, the Lorentz force along the J×B direction can generate the plasmas jet and make effective delivery of carbon ion particles and heat flux to samples. As a result, large-scale graphene flakes and high-purity single-walled carbon nanotubes were simultaneously generated by such new magnetically-enhanced anodic arc method. Arc imaging, scanning electron microscope (SEM), transmission electron microscope (TEM) and Raman spectroscopy were employed to analyze the characterization of carbon nanostructures. These findings indicate a wide spectrum of opportunities to manipulate with the properties of nanostructures produced in plasmas by means of controlling the

  13. Hetero-junctions of Boron Nitride and Carbon Nanotubes: Synthesis and Characterization

    Energy Technology Data Exchange (ETDEWEB)

    Yap, Yoke Khin

    2013-03-14

    Hetero-junctions of boron nitride nanotubes (BNNTs) and carbon nanotubes (CNTs) are expected to have appealing new properties that are not available from pure BNNTs and CNTs. Theoretical studies indicate that BNNT/CNT junctions could be multifunctional and applicable as memory, spintronic, electronic, and photonics devices with tunable band structures. This will lead to energy and material efficient multifunctional devices that will be beneficial to the society. However, experimental realization of BNNT/CNT junctions was hindered by the absent of a common growth technique for BNNTs and CNTs. In fact, the synthesis of BNNTs was very challenging and may involve high temperatures (up to 3000 degree Celsius by laser ablation) and explosive chemicals. During the award period, we have successfully developed a simple chemical vapor deposition (CVD) technique to grow BNNTs at 1100-1200 degree Celsius without using dangerous chemicals. A series of common catalyst have then been identified for the synthesis of BNNTs and CNTs. Both of these breakthroughs have led to our preliminary success in growing two types of BNNT/CNT junctions and two additional new nanostructures: 1) branching BNNT/CNT junctions and 2) co-axial BNNT/CNT junctions, 3) quantum dots functionalized BNNTs (QDs-BNNTs), 4) BNNT/graphene junctions. We have started to understand their structural, compositional, and electronic properties. Latest results indicate that the branching BNNT/CNT junctions and QDs-BNNTs are functional as room-temperature tunneling devices. We have submitted the application of a renewal grant to continue the study of these new energy efficient materials. Finally, this project has also strengthened our collaborations with multiple Department of Energy's Nanoscale Science Research Centers (NSRCs), including the Center for Nanophase Materials Sciences (CNMS) at Oak Ridge National Laboratory, and the Center for Integrated Nanotechnologies (CINTs) at Sandia National Laboratories and Los

  14. DNA-templated synthesis of Pt nanoparticles on single-walled carbon nanotubes.

    Science.gov (United States)

    Dong, Lifeng

    2009-11-18

    A series of electron microscopy characterizations demonstrate that single-stranded deoxyribonucleic acid (ssDNA) can bind to nanotube surfaces and disperse bundled single-walled carbon nanotubes (SWCNTs) into individual tubes. The ssDNA molecules on the nanotube surfaces demonstrate various morphologies, such as aggregated clusters and spiral wrapping around a nanotube with different pitches and spaces, indicating that the morphology of the SWCNT/DNA hybrids is not related solely to the base sequence of the ssDNA or the chirality or the diameter of the nanotubes. In addition to serving as a non-covalent dispersion agent, the ssDNA molecules bonded to the nanotube surface can provide addresses for localizing Pt(II) complexes along the nanotubes. The Pt nanoparticles obtained by a reduction of the Pt2+-DNA adducts are crystals with a size of direct ethanol/methanol fuel cells and nanoscale electronics.

  15. Conductivity and optical studies of plasticized solid polymer electrolytes doped with carbon nanotube

    Energy Technology Data Exchange (ETDEWEB)

    Ibrahim, Suriani, E-mail: sue_83@um.edu.my [Advanced Materials Research Laboratory, Department of Mechanical Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia); Ahmad, Roslina; Johan, Mohd Rafie [Advanced Materials Research Laboratory, Department of Mechanical Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia)

    2012-01-15

    Solid polymer electrolyte films based on Poly(ethylene oxide) (PEO) complexed with lithium hexafluorophosphate (LiPF{sub 6}), ethylene carbonate (EC) and amorphous carbon nanotube ({alpha}CNTs) were prepared by the solution cast technique. The conductivity increases from 10{sup -10} to 10{sup -5} Scm{sup -1} upon the addition of salt. The incorporation of EC and {alpha}CNTs to the salted polymer enhances the conductivity significantly to 10{sup -4} and 10{sup -3} Scm{sup -1}. The complexation of doping materials with polymer were confirmed by X-ray diffraction and infrared studies. Optical properties like direct band gap and indirect band gap were investigated for pure and doped polymer films in the wavelength range 200-400 nm. It was found that the energy gaps and band edge values shifted to lower energies on doping. - Highlights: > Optical band gap values show the decreasing trend with an increasing dopant concentration. > It is also observed that the absorption edge shifted to longer wavelength on doping. > Results of the optical measurements indicate the presence of a well-defined {pi}{yields}{pi}* transition associated with the formation of a conjugated C=O and/or C=O electronic structure.

  16. Conductivity and optical studies of plasticized solid polymer electrolytes doped with carbon nanotube

    International Nuclear Information System (INIS)

    Ibrahim, Suriani; Ahmad, Roslina; Johan, Mohd Rafie

    2012-01-01

    Solid polymer electrolyte films based on Poly(ethylene oxide) (PEO) complexed with lithium hexafluorophosphate (LiPF 6 ), ethylene carbonate (EC) and amorphous carbon nanotube (αCNTs) were prepared by the solution cast technique. The conductivity increases from 10 -10 to 10 -5 Scm -1 upon the addition of salt. The incorporation of EC and αCNTs to the salted polymer enhances the conductivity significantly to 10 -4 and 10 -3 Scm -1 . The complexation of doping materials with polymer were confirmed by X-ray diffraction and infrared studies. Optical properties like direct band gap and indirect band gap were investigated for pure and doped polymer films in the wavelength range 200-400 nm. It was found that the energy gaps and band edge values shifted to lower energies on doping. - Highlights: → Optical band gap values show the decreasing trend with an increasing dopant concentration. → It is also observed that the absorption edge shifted to longer wavelength on doping. → Results of the optical measurements indicate the presence of a well-defined π→π* transition associated with the formation of a conjugated C=O and/or C=O electronic structure.

  17. Polarized excitons and optical activity in single-wall carbon nanotubes

    Science.gov (United States)

    Chang, Yao-Wen; Jin, Bih-Yaw

    2018-05-01

    The polarized excitons and optical activity of single-wall carbon nanotubes (SWNTs) are studied theoretically by π -electron Hamiltonian and helical-rotational symmetry. By taking advantage of the symmetrization, the single-particle energy and properties of a SWNT are characterized with the corresponding helical band structure. The dipole-moment matrix elements, magnetic-moment matrix elements, and the selection rules can also be derived. Based on different selection rules, the optical transitions can be assigned as the parallel-polarized, left-handed circularly-polarized, and right-handed circularly-polarized transitions, where the combination of the last two gives the cross-polarized transition. The absorption and circular dichroism (CD) spectra are simulated by exciton calculation. The calculated results are well comparable with the reported measurements. Built on the foundation, magnetic-field effects on the polarized excitons and optical activity of SWNTs are studied. Dark-bright exciton splitting and interband Faraday effect in the CD spectrum of SWNTs under an axial magnetic field are predicted. The Faraday rotation dispersion can be analyzed according to the selection rules of circular polarizations and the helical band structure.

  18. Sol–gel synthesis of tantalum oxide and phosphonic acid-modified carbon nanotubes composite coatings on titanium surfaces

    International Nuclear Information System (INIS)

    Maho, Anthony; Detriche, Simon; Delhalle, Joseph; Mekhalif, Zineb

    2013-01-01

    Carbon nanotubes used as fillers in composite materials are more and more appreciated for the outstanding range of accessible properties and functionalities they generate in numerous domains of nanotechnologies. In the framework of biological and medical sciences, and particularly for orthopedic applications and devices (prostheses, implants, surgical instruments, …), titanium substrates covered by tantalum oxide/carbon nanotube composite coatings have proved to constitute interesting and successful platforms for the conception of solid and biocompatible biomaterials inducing the osseous regeneration processes (hydroxyapatite growth, osteoblasts attachment). This paper describes an original strategy for the conception of resistant and homogeneous tantalum oxide/carbon nanotubes layers on titanium through the introduction of carbon nanotubes functionalized by phosphonic acid moieties (-P(=O)(OH) 2 ). Strong covalent C-P bonds are specifically inserted on their external sidewalls with a ratio of two phosphonic groups per anchoring point. Experimental results highlight the stronger “tantalum capture agent” effect of phosphonic-modified nanotubes during the sol–gel formation process of the deposits compared to nanotubes bearing oxidized functions (-OH, -C=O, -C(=O)OH). Particular attention is also paid to the relative impact of the rate of functionalization and the dispersion degree of the carbon nanotubes in the coatings, as well as their wrapping level by the tantalum oxide matrix material. The resulting effect on the in vitro growth of hydroxyapatite is also evaluated to confirm the primary osseous bioactivity of those materials. Chemical, structural and morphological features of the different composite deposits described herein are assessed by X-ray photoelectron spectroscopy (XPS), scanning (SEM) and transmission (TEM) electronic microscopies, energy dispersive X-rays analysis (EDX) and peeling tests. Highlights: ► Formation of tantalum/carbon nanotube

  19. Sol–gel synthesis of tantalum oxide and phosphonic acid-modified carbon nanotubes composite coatings on titanium surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Maho, Anthony [Laboratory of Chemistry and Electrochemistry of Surfaces, University of Namur (FUNDP), Rue de Bruxelles 61, B-5000 Namur (Belgium); Fonds pour la Formation à la Recherche dans l' Industrie et dans l' Agriculture (FRIA), Rue d' Egmont 5, B-1000 Bruxelles (Belgium); Detriche, Simon; Delhalle, Joseph [Laboratory of Chemistry and Electrochemistry of Surfaces, University of Namur (FUNDP), Rue de Bruxelles 61, B-5000 Namur (Belgium); Mekhalif, Zineb, E-mail: zineb.mekhalif@fundp.ac.be [Laboratory of Chemistry and Electrochemistry of Surfaces, University of Namur (FUNDP), Rue de Bruxelles 61, B-5000 Namur (Belgium)

    2013-07-01

    /carbon nanotube composite coatings on titanium plates by sol–gel co-deposition. ► Synthesis and incorporation of MWCNTs bearing bisphosphonic acid moieties. ► Stronger “tantalum capture agent” effect of phosphonic-modified MWCNTs comparing to oxidized ones. ► Bioactivity of the resulting biomaterial qualitatively assessed by in vitro growth tests of hydroxyapatite.

  20. Synthesis of Vertically Aligned Carbon Nanotubes on Silicalite-1 Monolayer-Supported Substrate

    Directory of Open Access Journals (Sweden)

    Wei Zhao

    2014-01-01

    Full Text Available Monodisperse magnetic Fe3O4 nanoparticles (NPs with the size of ca. 3.5 nm were prepared and used as the catalysts for the synthesis of vertically aligned carbon nanotube (VACNT arrays. A silicalite-1 microcrystal monolayer was used as the support layer between catalyst NPs and the silicon substrate. Compared to our previous report which used radio-frequency- (rf- sputtered Fe2O3 film as the catalyst, Fe3O4 NPs that were synthesized by wet chemical method showed an improved catalytic ability with less agglomeration. The silicalite-1 crystal monolayer acted as an effective “buffer” layer to prevent the catalyst NPs from agglomerating during the reaction process. It is believed that this is the first report that realizes the vertical alignment of CNTs over the zeolite monolayer, namely, silicalite-1 microcrystal monolayer, instead of using the intermediate anodic aluminum oxide (AAO scaffold to regulate the growth direction of CNT products.

  1. Synthesis of benzimidazole-grafted graphene oxide/multi-walled carbon nanotubes composite for supercapacitance application

    Energy Technology Data Exchange (ETDEWEB)

    Srivastava, Rajesh Kr., E-mail: r05bhu@gmail.com [Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 637371 Singapore (Singapore); Xingjue, Wang [Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 637371 Singapore (Singapore); Kumar, Vinod [Department of Zoology, Banaras Hindu University, Varanasi (India); Srivastava, Anchal [Department of Physics, Banaras Hindu University, Varanasi (India); Singh, Vidya Nand [CSIR-National Physical Laboratory, New Delhi (India)

    2014-11-05

    Highlights: • We are reporting supercapacitance performance of BI-GO/MWCNTs composite. • The specific capacitance of BI-GO/MWCNTs is 275 and 460 F/g at 200 and 5 mV/s scan rate. • This composite has shown 224 F/g capacitance after 1300 cycles at 200 mV/s scan rate. - Abstract: We are reporting the fabrication, characterizations and supercapacitance performance of benzimidazole-grafted graphene oxide/multi-walled carbon nanotubes (BI-GO/MWCNTs) composite. The synthesis of BI-GO materials involves cyclization reaction of carboxylic groups on GO among the hydroxyl and amino groups on o-phenylenediamine. The BI-GO/MWCNTs composite has been fabricated via in situ reduction of BI-GO using hydrazine in presence of MWCNTs. Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), Raman spectroscopy, X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) have been used to characterize its surface and elemental composition. The uniform dispersion of MWCNTs with BI-GO helps to improve the charge transfer reaction during electrochemical process. The specific capacitance of BI-GO/MWCNTs composite is 275 and 460 F/g at 200 and 5 mV/s scan rate in 1 mol/L aqueous solution of H{sub 2}SO{sub 4}. This BI-GO/MWCNTs composite has shown 224 F/g capacitance after 1300 cycles at 200 mV/s scan rate, which represents its good electrochemical stability.

  2. Synthesis of benzimidazole-grafted graphene oxide/multi-walled carbon nanotubes composite for supercapacitance application

    International Nuclear Information System (INIS)

    Srivastava, Rajesh Kr.; Xingjue, Wang; Kumar, Vinod; Srivastava, Anchal; Singh, Vidya Nand

    2014-01-01

    Highlights: • We are reporting supercapacitance performance of BI-GO/MWCNTs composite. • The specific capacitance of BI-GO/MWCNTs is 275 and 460 F/g at 200 and 5 mV/s scan rate. • This composite has shown 224 F/g capacitance after 1300 cycles at 200 mV/s scan rate. - Abstract: We are reporting the fabrication, characterizations and supercapacitance performance of benzimidazole-grafted graphene oxide/multi-walled carbon nanotubes (BI-GO/MWCNTs) composite. The synthesis of BI-GO materials involves cyclization reaction of carboxylic groups on GO among the hydroxyl and amino groups on o-phenylenediamine. The BI-GO/MWCNTs composite has been fabricated via in situ reduction of BI-GO using hydrazine in presence of MWCNTs. Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), Raman spectroscopy, X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) have been used to characterize its surface and elemental composition. The uniform dispersion of MWCNTs with BI-GO helps to improve the charge transfer reaction during electrochemical process. The specific capacitance of BI-GO/MWCNTs composite is 275 and 460 F/g at 200 and 5 mV/s scan rate in 1 mol/L aqueous solution of H 2 SO 4 . This BI-GO/MWCNTs composite has shown 224 F/g capacitance after 1300 cycles at 200 mV/s scan rate, which represents its good electrochemical stability

  3. Liquid-phase synthesis of vertically aligned carbon nanotubes and related nanomaterials on preheated alloy substrates

    Science.gov (United States)

    Yamagiwa, Kiyofumi

    2018-02-01

    Carbon nanotubes (CNTs) and related nanocarbons were selectively synthesized on commercially available alloy substrates by a simple liquid-phase technique. Fe- and Ni-rich stainless-steel (JIS SUS316L and Inconel®600, respectively) and Ni-Cu alloy (Monel®400) substrates were used for the synthesis, and each substrate was preheated in air to promote the self-formation of catalyst nanolayers on the surface. The substrates were resistance heated in ethanol without any addition of catalysts to grow CNTs. The yield of the CNTs effectively increased when the preheating process was employed. Highly aligned CNT arrays grew on the SUS316L substrate, while non-aligned CNTs and distinctive twisted fibers were observed on the other substrates. An Fe oxide layer was selectively formed on the preheated SUS316L substrate promoting the growth of the CNT arrays. Characterizations including cyclic voltammetry for the arrays revealed that the CNTs possess a comparatively defect-rich surface, which is a desirable characteristic for its application such as electrode materials for capacitors.

  4. Synthesis and Electrochemical Performance of SiOC-Carbon Nanotube Composite Coatings

    Science.gov (United States)

    Bhandavat, Romil; Cologna, Marco; Raj, Rishi; Singh, Gurpreet

    2012-02-01

    Rechargeable battery anodes made from crystalline Si-based nanostructures have been shown to possess high experimental first cycle capacities (3000 mAh/g), but face challenges in sustaining these capacities beyond initial cycles mainly due to large volume expansion (400 percent) and chemical degradation (pulverization). Polymer-derived ceramic SiOC due to its high thermodynamic stability and nano domain structure could present a viable alternative. Additionally, functionalization of SiOC with carbon nanotubes could result in increased electronic and ionic conductivities in the ceramic. Here, we demonstrate synthesis and electrochemical characterization of SiOC-CNT composite coatings for use in Li-ion battery anode. Materials characterization performed using electron microscopy, Infrared (FT-IR), and X-ray photoelectron spectroscopy suggests non-covalent functionalization of CNT with oxygen moieties in SiOC. Sustained battery capacities of over 700 mAh/g and first cycle columbic efficiencies of about 75 percent were achieved. Future work will involve determination of lithium ion intercalation sites characterized by electron microscopy whereas cyclic voltammetry analysis will access the sequential change in anode chemistry.

  5. Multiwalled Carbon Nanotube Synthesis Using Arc Discharge with Hydrocarbon as Feedstock

    Directory of Open Access Journals (Sweden)

    K. T. Chaudhary

    2013-01-01

    Full Text Available Synthesis of multiwalled carbon nanotube (MWCNT by arc discharge process is investigated with methane (CH4 as background and feedstock gas. The arc discharge is carried out between two graphite electrodes for ambient pressures 100, 300, and 500 torr and arc currents 50, 70, and 90 A. Plasma kinetics such as the density and temperature for arc discharge carbon plasma is determined to find out the contribution of physical parameters as arc current and ambient pressure on the plasma dynamics and growth of MWCNT. With increase in applied arc current and ambient pressure, an increase in plasma temperature and density is observed. The synthesized samples of MWCNT at different experimental conditions are characterized by transmission electron microscopy, scanning electron microscopy, Raman spectroscopy, Fourier transform infrared spectroscopy, and X-ray diffraction. A decrease in the diameter and improvement in structure quality and growth of MWCNT are observed with increase in CH4 ambient pressure and arc current. For CH4 ambient pressure 500 torr and arc current 90 A, the well-aligned and straight MWCNT along with graphene stakes are detected.

  6. Synthesis of polymer-derived ceramic Si(B)CN-carbon nanotube composite by microwave-induced interfacial polarization.

    Science.gov (United States)

    Bhandavat, R; Kuhn, W; Mansfield, E; Lehman, J; Singh, G

    2012-01-01

    We demonstrate synthesis of a polymer-derived ceramic (PDC)-multiwall carbon nanotube (MWCNT) composite using microwave irradiation at 2.45 GHz. The process takes about 10 min of microwave irradiation for the polymer-to-ceramic conversion. The successful conversion of polymer coated carbon nanotubes to ceramic composite is chemically ascertained by Fourier transform-infrared and X-ray photoelectron spectroscopy and physically by thermogravimetric analysis and transmission electron microscopy characterization. Frequency dependent dielectric measurements in the S-Band (300 MHz to 3 GHz) were studied to quantify the extent of microwave-CNT interaction and the degree of selective heating available at the MWCNT-polymer interface. Experimentally obtained return loss of the incident microwaves in the specimen explains the reason for heat generation. The temperature-dependent permittivity of polar molecules further strengthens the argument of internal heat generation. © 2011 American Chemical Society

  7. Synthesis of suspended carbon nanotubes on silicon inverse-opal structures by laser-assisted chemical vapour deposition

    International Nuclear Information System (INIS)

    Shi, J; Lu, Y F; Wang, H; Yi, K J; Lin, Y S; Zhang, R; Liou, S H

    2006-01-01

    Suspended single-walled carbon nanotubes (SWNTs) have been synthesized on Si inverse-opal structures by laser-assisted chemical vapour deposition (LCVD). A CW CO 2 laser at 10.6 μm was used to directly irradiate the substrates during the LCVD process. At a laser power density of 14.3 MW m -2 , suspended SWNT networks were found predominantly rooted at the sharp edges in the Si inverse-opal structures. Raman spectroscopy indicated that the SWNT networks were composed of high-quality defect-free SWNTs with an average diameter of 1.3 nm. At a lower laser power density (6.4 MW m -2 ), multi-walled carbon nanotubes (MWNTs) were grown on the entire surface of the substrates. The preference for the synthesis of SWNTs or MWNTs was attributed to the difference in the catalyst sizes as well as the growth temperature in the LCVD process

  8. 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.

  9. Large-scale aligned silicon carbonitride nanotube arrays: Synthesis, characterization, and field emission property

    International Nuclear Information System (INIS)

    Liao, L.; Xu, Z.; Liu, K. H.; Wang, W. L.; Liu, S.; Bai, X. D.; Wang, E. G.; Li, J. C.; Liu, C.

    2007-01-01

    Large-scale aligned silicon carbonitride (SiCN) nanotube arrays have been synthesized by microwave-plasma-assisted chemical vapor deposition using SiH 4 , CH 4 , and N 2 as precursors. The three elements of Si, C, and N are chemically bonded with each other and the nanotube composition can be adjusted by varying the SiH 4 concentration, as revealed by electron energy loss spectroscopy and x-ray photoelectron spectroscopy. The evolution of microstructure of the SiCN nanotubes with different Si concentrations was characterized by high-resolution transmission electron microscopy and Raman spectroscopy. The dependence of field emission characteristics of the SiCN nanotubes on the composition has been investigated. With the increasing Si concentration, the SiCN nanotube exhibits more favorable oxidation resistance, which suggests that SiCN nanotube is a promising candidate as stable field emitter

  10. Study on the effect of the metal–support (Fe-MgO and Pt-MgO) interaction in alcohol-CVD synthesis of carbon nanotubes

    International Nuclear Information System (INIS)

    Steplewska, Anna; Borowiak-Palen, Ewa

    2011-01-01

    This study presents the effect of the metal–support interaction in two systems: (1) iron particle, and (2) platinum particles, being supported on magnesium oxide (MgO) nanopowder in alcohol-CVD process for carbon nanotubes (CNTs) growth. The employment of the different metals but the same substrate (with equal molar ratio) resulted in the synthesis of single-walled CNTs (SWCNTs) or double-walled CNTs (DWCNTs), using iron and platinum, respectively. Furthermore, along with the prolongation of the process time, the decrease of the mean nanotubes diameter in case of iron-catalyzed materials was detected. Interestingly, the extention of the growth time in the synthesis using Pt/MgO resulted in the synthesis of the thicker mean nanotubes diameter. However, for both applied catalytic systems the reduction of the diameter distribution of the tubes and the increase of relative purity of the samples upon the growth time increase were detected.

  11. Study on the effect of the metal-support (Fe-MgO and Pt-MgO) interaction in alcohol-CVD synthesis of carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Steplewska, Anna, E-mail: asteplewska@zut.edu.pl; Borowiak-Palen, Ewa [West Pomeranian University of Technology, Centre of Knowledge Based Nanomaterials and Technologies, Institute of Chemical and Environment Engineering (Poland)

    2011-05-15

    This study presents the effect of the metal-support interaction in two systems: (1) iron particle, and (2) platinum particles, being supported on magnesium oxide (MgO) nanopowder in alcohol-CVD process for carbon nanotubes (CNTs) growth. The employment of the different metals but the same substrate (with equal molar ratio) resulted in the synthesis of single-walled CNTs (SWCNTs) or double-walled CNTs (DWCNTs), using iron and platinum, respectively. Furthermore, along with the prolongation of the process time, the decrease of the mean nanotubes diameter in case of iron-catalyzed materials was detected. Interestingly, the extention of the growth time in the synthesis using Pt/MgO resulted in the synthesis of the thicker mean nanotubes diameter. However, for both applied catalytic systems the reduction of the diameter distribution of the tubes and the increase of relative purity of the samples upon the growth time increase were detected.

  12. Synthesis of gold nanoclusters: a fluorescent marker for water-soluble TiO2 nanotubes

    International Nuclear Information System (INIS)

    Ratanatawanate, Chalita; Yu Jing; Zhou Chen; Zheng Jie; Balkus, Kenneth J Jr

    2011-01-01

    The first example of a water-soluble wrapped titania nanotube (TNT) decorated with fluorescent gold nanoparticles has been prepared. Gold nanoparticles ∼ 1.6 nm in diameter were grown on the TiO 2 nanotubes using a thiolactic acid linker to control the size. The gold clusters emit at 660 nm in water and were imaged using confocal microscopy. The gold decorated TNTs were suspended in water by wrapping the nanotubes with poly-L-arginine.

  13. TiO2 Nanotubes: Recent Advances in Synthesis and Gas Sensing Properties

    Directory of Open Access Journals (Sweden)

    Giorgio Sberveglieri

    2013-10-01

    Full Text Available Synthesis—particularly by electrochemical anodization-, growth mechanism and chemical sensing properties of pure, doped and mixed titania tubular arrays are reviewed. The first part deals on how anodization parameters affect the size, shape and morphology of titania nanotubes. In the second part fabrication of sensing devices based on titania nanotubes is presented, together with their most notable gas sensing performances. Doping largely improves conductivity and enhances gas sensing performances of TiO2 nanotubes

  14. In situ preparation of composite from conjugated polyschiff bases and multiwalled carbon nanotube: Synthesis, electrochromic, acidochromic properties

    International Nuclear Information System (INIS)

    Ma Lina; Cai Jiwei; Zhao Ping; Niu Haijun; Wang Cheng; Bai Xuduo; Wang Wen

    2012-01-01

    Graphical abstract: The introduction of carbon nanotubes greatly improves the photochromic property of the composites. Highlights: ► MWNTs/PSB composite was prepared by in situ polymerization with a new type of PSB. ► The introduction of carbon nanotubes greatly improves the photochromic property of the composites. ► The composites exhibited excellent thermal stability and reversible electrochemical behavior. - Abstract: Polyschiff base (PSB) which has the structure of C=N double bond is well known as conducting material with high thermal resistance, chemical and electrical properties. Recently, it was used as hole transporting material in organic light emitting diode (OLED), chemical sensor and electrochromic materials. Carbon nanotubes (CNTs) with excellent properties such as unique electrical, mechanical, optical and chemical properties are promising reinforcing materials for polymer composites which improve the comprehensive properties of polymers. In this paper, conjugated PSB-grafted multiwalled carbon nanotubes (MWNTs) composite was prepared by in situ polymerization. The resultant composites were characterized by thermogravimetric (TGA), scanning electron microscopy (SEM), UV–vis absorption, photoluminescence (PL), cyclic voltammograms (CV), infrared spectroscopy (IR) and Raman spectroscopy. The composites exhibited high thermal stability and excellent reversibilities of electrochromic, photochromic, acidochromic characteristics, with the color change from the light yellow to blue.

  15. Optical transmission of nematic liquid crystal 5CB doped by single-walled and multi-walled carbon nanotubes.

    Science.gov (United States)

    Lisetski, L N; Fedoryako, A P; Samoilov, A N; Minenko, S S; Soskin, M S; Lebovka, N I

    2014-08-01

    Comparative studies of optical transmission of single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs), dispersed in nematic liquid crystal matrix 5CB, were carried out. The data evidence violations of Beer-Lambert-Bouguer (BLB) law both in cell thickness and concentration dependencies. The most striking is the fact that optical transmission dependencies for SWCNTs and MWCNTs were quite different in the nematic phase, but they were practically indistinguishable in the isotropic phase. Monte Carlo simulations of the impact of aggregation on direct transmission and violation of BLB law were also done. The results were discussed accounting for the tortuous shape of CNTs, their physical properties and aggregation, as well as strong impact of perturbations of the nematic 5CB structure inside coils and in the vicinity of CNT aggregates.

  16. pH-dependence of the optical bio-sensor based on DNA-carbon nanotube

    International Nuclear Information System (INIS)

    Vu Thuy Huong; Quach Kha Quang; Tran Thanh Thuy; Phan Duc Anh; Ngo Van Thanh; Nguyen Ai Viet

    2010-01-01

    In 2006, Daniel A. Heller et al. [1] demonstrated that carbon nanotubes (CNNTs) wrapped with DNA can be placed inside living cells and detect trace amounts of harmful contaminants using near infrared light. This discovery could lead to new types of optical sensors and biomarkers at the sub cellular level. The working principle of this optical bio-sensor from DNA and CNNTs can be explained by a simple theoretical model which was introduced in [3]. In this paper, the pH-dependence of DNA and the pH-dependence of solution around CNNTs are shown by using data analysis method. By substituting them into the same model, the pH-dependence of DNA-wrapped CNNTs was elicited in this paper. The range of parameters for workable conditions of this bio-sensor was indicated that the solution should have pH from 6 to 9 and the concentration of ions should be more than a critical value. These results are according to the experimental data and the deduction about pH and salt concentration in solution. They are very useful as using such a new bio-sensor like this in living environment. (author)

  17. Carbon Nanotube Networks Reinforced by Silver Nanowires with Improved Optical Transparency and Conductivity

    Science.gov (United States)

    Martine, Patricia; Fakhimi, Azin; Lin, Ling; Jurewicz, Izabela; Dalton, Alan; Zakhidov, Anvar A.; Baughman, Ray H.

    2015-03-01

    We have fabricated highly transparent and conductive free-standing nanocomposite thin film electrodes by adding silver nanowires (AgNWs) to dry-spun Multiwall Carbon Nanotube (MWNT) aerogels. This nanocomposite exhibits desirable properties such as high optical transmittance, excellent flexibility and enhanced electrical conductivity. The incorporation of the AgNWs to the MWNT aerogels was accomplished by using a spray coating method. The optical transparency and sheet resistance of the nanocomposite was tuned by adjusting the concentration of AgNWs, back pressure and nozzle distance of the spray gun to the MWNT aerogel during deposition. As the solvent evaporated, the aerogel MWNT bundles densified via surface tension which caused the MWNT bundles to collapse. This adjustable process was responsible in forming well defined apertures that increased the nanocomposite's transmittance up to 90 percent. Via AgNWs percolation and random interconnections between separate MWNT bundles in the aerogel matrix, the sheet resistance decreased from 1 K ohm/sq to less than 100 ohm/sq. Alan G. MacDiarmid NanoTech Institute

  18. Optical detection of CO and CO2 temperature dependent desorption from carbon nanotube clusters

    International Nuclear Information System (INIS)

    Chistiakova, M V; Armani, A M

    2014-01-01

    The development of new materials relies on high precision methods to quantify adsorption/desorption of gases from surfaces. One commonly used approach is temperature programmed desorption spectroscopy. While this approach is very accurate, it requires complex instrumentation, and it is limited to performing experiments under high vacuum, thus restricting experimental scope. An alternative approach is to integrate the surface of interest directly onto a detector face, creating an active substrate. One surface that has applications in numerous areas is the carbon nanotube (CNT). As such, an active substrate that integrates a CNT surface on a sensor and is able to perform measurements in ambient environments will have significant impact. In the present work, we have developed an active substrate that combines an optical sensor with a CNT cluster substrate. The optical sensor is able to accurately probe the temperature dependent desorption of carbon monoxide and carbon dioxide gases from the CNT cluster surface. This active substrate will enable a wide range of temperature dependent desorption measurements to be performed from a scientifically interesting material system. (paper)

  19. Low temperature synthesis of polyaniline-crystalline TiO2-halloysite composite nanotubes with enhanced visible light photocatalytic activity.

    Science.gov (United States)

    Li, Cuiping; Wang, Jie; Guo, Hong; Ding, Shujiang

    2015-11-15

    A series of one-dimensional polyaniline-crystalline TiO2-halloysite composite nanotubes with different mass ratio of polyaniline to TiO2 are facilely prepared by employing the low-temperature synthesis of crystalline TiO2 on halloysite nanotubes. The halloysite nanotubes can adsorb TiO2/polyaniline precursors and induce TiO2 nanocrystals/polyaniline to grow on the support in situ simultaneously. By simply adjusting the acidity of reaction system, PANI-crystalline TiO2-HA composite nanotubes composed of anatase, a mixed phase TiO2 and different PANI redox state are obtained. The XRD and UV-vis results show that the surface polyaniline sensitization has no effect on the crystalline structure of halloysite and TiO2 and the light response of TiO2 is extended to visible-light regions. Photocatalysis test results reveal the photocatalytic activity will be affected by the pH value and the volume ratio of ANI to TTIP. The highest photocatalytic activity is achieved with the composite photocatalysts prepared at pH 0.5 and 1% volume ratio of ANI and TTIP owing to the sensitizing effect of polyaniline and the charge transfer from the photoexcited PANI sensitizer to TiO2. Moreover, the PANI-TiO2-HA composite nanotubes synthesized by one-step at pH 0.5 with 1% volume ratio of ANI to TTIP exhibit higher visible light photocatalytic activity than those synthesized by the two-step. Heterogeneous PANI-TiO2-HA composite nanotubes prepared at pH 0.5 exhibit a higher degradation activity than that prepared at pH 1.5. The redoped experiment proves that the PANI redox state plays the main contribution to the enhanced visible light catalytic degradation efficiency of PANI-TiO2-HA prepared at pH 0.5. Furthermore, the heterogeneous PANI-crystalline TiO2-HA nanotubes have good photocatalytic stability and can be reused four times with only gradual loss of activity under visible light irradiation. Copyright © 2015 Elsevier Inc. All rights reserved.

  20. Novelty of Dynamic Process in the Synthesis of Biocompatible Silica Nanotubes by Biomimetic Glycyldodecylamide as a Soft Template.

    Science.gov (United States)

    Choi, Hyejung; Kim, Joong-Jo; Mo, Yong-Hwan; Reddy, Benjaram M; Park, Sang-Eon

    2017-10-10

    A dynamic process in the synthesis of silica nanotubes (SNTs) by utilizing glycyldodecylamide (GDA) as a soft template was thoroughly investigated. The morphological evolution from GDA to SNTs was deeply explored to elucidate the formation mechanism for optimizing the synthesis procedure. Various analytical tools, namely, XRD, FTIR, SEM, TEM, Z-potential, and N 2 adsorption/desorption isotherms, were employed during the synthesis procedure. The interactive structure of GDA was also investigated using TEM-EDX as a function of aging time. These studies revealed the stepwise morphology of nanograin, nanofiber, curved plate, and nanotube in the ethanol/water solution when aged at room temperature. The supramolecular GDA molded the vesicle type nanostructure which was surrounded by silica and facilitated the formation of uniform SNTs. The stimulus for GDA to be curved into a vesicle was the intermolecular hydrogen bonding between adjacent amide groups of the template molecules. This was illustrated by FTIR spectra of GDA-silica intermediate by detecting the transition of amide I peak from 1678 to 1635 cm -1 . The effect of hydrogen bonding became stronger when the sample was aged.

  1. Preparation, optical properties of ZnO, ZnO:Al nanorods and Y(OH)3:Eu nanotube

    International Nuclear Information System (INIS)

    Tran Kim Anh; Dinh Xuan Loc; Lam thi Kieu Giang; Le Quoc Minh; Strek, Wieslaw

    2009-01-01

    ZnO, ZnO:Al nanorods and Y(OH) 3 nanotubes have been prepared by the chemical vapor deposition and liquid phase synthesis. ZnO nanorods with diameter of 50 - 100 nm and length of 5 μm have been obtained by the CVD method. ZnO:Al nanorods were synthesized by the hydrothermal method from ZnSO 4. and Al 2 (SO 4 ) 3 . Nanorods and nanotubes of Y(OH) 3 with diameter of 200 nm and length of several micrometers were prepared by the soft template method. The crystal structure and morphology of rods and tubes were analyzed by the X-Ray diffraction and FE-SEM. The influence of fabrication conditions and Al, Eu concentration have been discussed.

  2. Preparation, optical properties of ZnO, ZnO:Al nanorods and Y(OH){sub 3}:Eu nanotube

    Energy Technology Data Exchange (ETDEWEB)

    Tran Kim Anh; Dinh Xuan Loc; Lam thi Kieu Giang; Le Quoc Minh [Institute of Materials Science, Vietnamese Academy of Science and Technology 18 Hoang Quoc Viet, Nghia Do, Cau Giay, Hanoi (Viet Nam); Strek, Wieslaw [Institute of Low Temperature and Structure Research, PAN, 2 Okolna, Wroclaw (Poland)], E-mail: kimanh1949@gmail.com

    2009-01-01

    ZnO, ZnO:Al nanorods and Y(OH){sub 3} nanotubes have been prepared by the chemical vapor deposition and liquid phase synthesis. ZnO nanorods with diameter of 50 - 100 nm and length of 5 {mu}m have been obtained by the CVD method. ZnO:Al nanorods were synthesized by the hydrothermal method from ZnSO{sub 4.} and Al{sub 2}(SO{sub 4}){sub 3}. Nanorods and nanotubes of Y(OH){sub 3} with diameter of 200 nm and length of several micrometers were prepared by the soft template method. The crystal structure and morphology of rods and tubes were analyzed by the X-Ray diffraction and FE-SEM. The influence of fabrication conditions and Al, Eu concentration have been discussed.

  3. Polypyrrole nanotubes and their carbonized analogs: synthesis, characterization, gas sensing properties

    Czech Academy of Sciences Publication Activity Database

    Kopecká, J.; Mrlík, M.; Olejník, R.; Kopecký, D.; Vrňata, M.; Prokeš, J.; Bober, Patrycja; Morávková, Zuzana; Trchová, Miroslava; Stejskal, Jaroslav

    2016-01-01

    Roč. 16, č. 11 (2016), s. 1-13, č. článku 1917. ISSN 1424-8220 R&D Projects: GA ČR(CZ) GA16-02787S Institutional support: RVO:61389013 Keywords : polypyrrole nanotube * carbon nanotube * carbonization Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.677, year: 2016

  4. Carbon nanotubes decorated with palladium nanoparticles : Synthesis, characterization, and catalytic activity

    NARCIS (Netherlands)

    Karousis, Nikolaos; Tsotsou, Georgia-Eleni; Evangelista, Fabrizio; Rudolf, Petra; Ragoussis, Nikitas; Tagmatarchis, Nikos

    2008-01-01

    In this article, the in situ preparation of palladium nanoparticles, as mediated by the self-regulated reduction of palladium acetate with the aid of sodium dodecyl sulfate (SDS), followed by subsequent deposition onto single-walled carbon nanotubes and multimalled carbon nanotubes (MWCNTs), is

  5. 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.

  6. Theoretical exploration of structural, electro-optical and magnetic properties of gallium-doped silicon carbide nanotubes

    Science.gov (United States)

    Behzad, Somayeh; Chegel, Raad; Moradian, Rostam; Shahrokhi, Masoud

    2014-09-01

    The effects of gallium doping on the structural, electro-optical and magnetic properties of (8,0) silicon carbide nanotube (SiCNT) are investigated by using spin-polarized density functional theory. It is found from the calculation of the formation energies that gallium substitution for silicon atom is preferred. Our results show that gallium substitution at either single carbon or silicon atom site in SiCNT could induce spontaneous magnetization. The optical studies based on dielectric function indicate that new transition peaks and a blue shift are observed after gallium doping.

  7. Synthesis of uniform carbon at silica nanocables and luminescent silica nanotubes with well controlled inner diameters

    International Nuclear Information System (INIS)

    Qian Haisheng; Yu Shuhong; Ren Lei; Yang Yipeng; Zhang Wei

    2006-01-01

    Uniform carbon at silica nanocables and silica nanotubes with well-controlled inner diameters can be synthesized in an easy way by a sacrificial templating method. This was performed using carbon nanofibres as hard templates that were synthesized previously by a hydrothermal carbonization process. Silica nanotubes with well-controlled inner diameters were synthesized from carbon at silica core-shell nanostructures by removal of the core carbon component. The inner diameters of the as-prepared silica nanotubes can be well controlled from several nanometres to hundreds of nanometres by adjusting the diameters of the carbon nanofibres. The silica nanotubes synthesized by this method display strong photoluminescence in ultraviolet at room temperature. Such uniform silica nanotubes might find potential applications in many fields such as encapsulation, catalysis, chemical/biological separation, and sensing

  8. 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.

  9. 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.

  10. Tailoring crystallinity and configuration of silica nanotubes by electron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Taguchi, Tomitsugu, E-mail: taguchi.tomitsugu@jaea.go.jp; Yamaguchi, Kenji

    2015-05-01

    Highlights: •Single-crystal SiO{sub 2} nanotubes were successfully synthesized for the first time. •The single-crystal SiO{sub 2} was α-crystobalite. •Desired area of single-crystal nanotube can be changed to amorphous by electron irradiation. •The configuration of nanotube can be controlled using the focused electron irradiation technique. -- Abstract: SiO{sub 2} nanotubes show potential in applications such as nanoscale electronic and optical devices, bioseparation, biocatalysis, and nanomedicine. As-grown SiO{sub 2} nanotubes in the previous studies always have an amorphous wall, and here we demonstrate the successful synthesis of single-crystal nanotubes for the first time by the heat treatment of SiC nanotubes at 1300 °C for 10 h under low-vacuum conditions. According to TEM observations, the single-crystal SiO{sub 2} was α-cristobalite. We also demonstrate that single-crystal SiO{sub 2} nanotubes can be transformed into amorphous SiO{sub 2} nanotubes by electron beam irradiation. Moreover, we synthesized a crystalline/amorphous SiO{sub 2} composite nanotube, in which crystalline and amorphous SiO{sub 2} coexisted in different localized regions. In addition, for biomedical applications such as drug delivery systems, controlling the configuration of the open end, the diameter, and capsulation of SiO{sub 2} nanotubes is crucial. We can also obturate, capsulate, and cut a SiO{sub 2} nanotube, as well as modify the inner diameter of the nanotube at a specific, nanometer-sized region using the focused electron beam irradiation technique.

  11. Functionalization of carbon nanotubes with silver clusters

    International Nuclear Information System (INIS)

    Cveticanin, Jelena; Krkljes, Aleksandra; Kacarevic-Popovic, Zorica; Mitric, Miodrag; Rakocevic, Zlatko; Trpkov, Djordje; Neskovic, Olivera

    2010-01-01

    In this paper, an advanced method of one-step functionalization of single and multi walled carbon nanotubes (SWCNTs and MWCNTs) using γ-irradiation was described. Two synthesis procedures, related with different reduction species, were employed. For the first time, poly(vinyl alcohol) PVA is successfully utilized as a source to reduce silver (Ag) metal ions without having any additional reducing agents to obtain Ag nanoparticles on CNTs. The decoration of carbon nanotubes with Ag nanoparticles takes place through anchoring of (PVA) on nanotube's surface. Optical properties of as-prepared samples and mechanism responsible for the functionalization of carbon nanotubes were investigated using UV-vis and FTIR spectroscopy, respectively. Decorated carbon nanotubes were visualized using microscopic techniques: transmission electron microscopy and scanning tunneling microscopy. Also, the presence of Ag on the nanotubes was confirmed using energy dispersive X-ray spectroscopy. This simple and effective method of making a carbon nanotube type of composites is of interest not only for an application in various areas of technology and biology, but for investigation of the potential of radiation technology for nanoengineering of materials.

  12. Separation of methane-nitrogen mixtures using synthesis vertically aligned carbon nanotube membranes

    Science.gov (United States)

    Gilani, Neda; Daryan, Jafar Towfighi; Rashidi, Alimorad; Omidkhah, Mohammad Reza

    2012-03-01

    In this paper, capabilities of carbon nanotube (CNT) membranes fabricated in cylindrical pores of anodic aluminum oxide (AAO) substrate to separate the binary mixtures of CH4/N2 are studied experimentally. For this purpose, the permeability and selectivity of three CNT/AAO membranes with different growth time as 6 h, 12 h and 18 h are investigated. CNTs are grown vertically through holes of AAO with average pore diameter of 45 nm by chemical vapor deposition (CVD) of acetylene gas. CNT/AAO membranes with the same CNTs' outer diameters and different inner diameters are synthesized. The AAO are characterized by SEM analysis. In addition, SEM, TEM, BET N2 adsorption analysis and Raman spectroscopy are employed to characterize aligned CNTs. Study on permeability and selectivity of membranes for three binary mixtures of CH4/N2 showed that when the CNT inner diameters are 34 nm and 24 nm, viscous flow is the governing mechanism and insignificant selectivities of 1.2-1.24 are achieved. However, the membrane with CNT inner diameter and wall thickness of 8 nm and 16 nm respectively is considerably selective for CH4 over N2. It was also found that CH4 mole fraction in the feed and upstream feed pressure have major effect on permeability and selectivity. The membrane with 18 h synthesis time showed the selectivity is in the range of 1.8-3.85. The enhancement factor for N2 single gas diffusivity was also found to be about three times larger than that predicted by Knudsen diffusion model.

  13. 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.

  14. Optical Aperture Synthesis Object's Information Extracting Based on Wavelet Denoising

    International Nuclear Information System (INIS)

    Fan, W J; Lu, Y

    2006-01-01

    Wavelet denoising is studied to improve OAS(optical aperture synthesis) object's Fourier information extracting. Translation invariance wavelet denoising based on Donoho wavelet soft threshold denoising is researched to remove Pseudo-Gibbs in wavelet soft threshold image. OAS object's information extracting based on translation invariance wavelet denoising is studied. The study shows that wavelet threshold denoising can improve the precision and the repetition of object's information extracting from interferogram, and the translation invariance wavelet denoising information extracting is better than soft threshold wavelet denoising information extracting

  15. Batch fabrication of optical actuators using nanotube-elastomer composites towards refreshable Braille displays

    Science.gov (United States)

    Camargo, C. J.; Campanella, H.; Marshall, J. E.; Torras, N.; Zinoviev, K.; Terentjev, E. M.; Esteve, J.

    2012-07-01

    This paper reports an opto-actuable device fabricated using micro-machined silicon moulds. The actuating component of the device is made from a composite material containing carbon nanotubes (CNTs) embedded in a liquid crystal elastomer (LCE) matrix. We demonstrate the fabrication of a patterned LCE-CNT film by a combination of mechanical stretching and thermal cross-linking. The resulting poly-domain LCE-CNT film contains ‘blister-shaped’ mono-domain regions, which reversibly change their shape under light irradiation and hence can be used as dynamic Braille dots. We demonstrate that blisters with diameters of 1.0 and 1.5 mm, and wall thickness 300 µm, will mechanically contract under irradiation by a laser diode with optical power up to 60 mW. The magnitude of this contraction was up to 40 µm, which is more than 10% of their height in the ‘rest’ state. The stabilization time of the material is less than 6 s for both actuation and recovery. We also carried out preliminary tests on the repeatability of this photo-actuation process, observing no material or performance degradation. This manufacturing approach establishes a starting point for the design and fabrication of wide-area tactile actuators, which are promising candidates for the development of new Braille reading applications for the visually impaired.

  16. Production of carbon nanotubes: Chemical vapor deposition synthesis from liquefied petroleum gas over Fe-Co-Mo tri-metallic catalyst supported on MgO

    Energy Technology Data Exchange (ETDEWEB)

    Setyopratomo, P., E-mail: puguh-sptm@yahoo.com; Wulan, Praswasti P. D. K., E-mail: wulanmakmur@gmail.com; Sudibandriyo, M., E-mail: msudib@che.ui.ac.id [Chemical Engineering Department, University of Indonesia, Depok Campus, Depok 16424 (Indonesia)

    2016-06-03

    Carbon nanotubes were produced by chemical vapor deposition method to meet the specifications for hydrogen storage. So far, the various catalyst had been studied outlining their activities, performances, and efficiencies. In this work, tri-metallic catalyst consist of Fe-Co-Mo supported on MgO was used. The catalyst was prepared by wet-impregnation method. Liquefied Petroleum Gas (LPG) was used as carbon source. The synthesis was conducted in atmospheric fixed bed reactor at reaction temperature range 750 – 850 °C for 30 minutes. The impregnation method applied in this study successfully deposed metal component on the MgO support surface. It found that the deposited metal components might partially replace Mg(OH){sub 2} or MgO molecules in their crystal lattice. Compare to the original MgO powder; it was significant increases in pore volume and surface area has occurred during catalyst preparation stages. The size of obtained carbon nanotubes is ranging from about 10.83 nm OD/4.09 nm ID up to 21.84 nm OD/6.51 nm ID, which means that multiwall carbon nanotubes were formed during the synthesis. Yield as much as 2.35 g.CNT/g.catalyst was obtained during 30 minutes synthesis and correspond to carbon nanotubes growth rate of 0.2 μm/min. The BET surface area of the obtained carbon nanotubes is 181.13 m{sup 2}/g and around 50 % of which is contributed by mesopores. Micropore with half pore width less than 1 nm contribute about 10% volume of total micro and mesopores volume of the carbon nanotubes. The existence of these micropores is very important to increase the hydrogen storage capacity of the carbon nanotubes.

  17. A Review of Double-Walled and Triple-Walled Carbon Nanotube Synthesis and Applications

    Directory of Open Access Journals (Sweden)

    Kazunori Fujisawa

    2016-04-01

    Full Text Available Double- and triple-walled carbon nanotubes (DWNTs and TWNTs consist of coaxially-nested two and three single-walled carbon nanotubes (SWNTs. They act as the geometrical bridge between SWNTs and multi-walled carbon nanotubes (MWNTs, providing an ideal model for studying the coupling interactions between different shells in MWNTs. Within this context, this article comprehensively reviews various synthetic routes of DWNTs’ and TWNTs’ production, such as arc discharge, catalytic chemical vapor deposition and thermal annealing of pea pods (i.e., SWNTs encapsulating fullerenes. Their structural features, as well as promising applications and future perspectives are also discussed.

  18. Understanding the mechanism of nanotube synthesis for controlled production of specific (n,m) structures

    Energy Technology Data Exchange (ETDEWEB)

    Resasco, Daniel E.

    2010-02-11

    This report shows the extensive research on the mechanism responsible for the formation of single walled carbon nanotubes in order to get control over their structural parameters (diameter and chirality). Catalyst formulations, pre-treatment conditions, and reaction conditions are described in detail as well as mechanisms to produce nanotubes structures of specific arrays (vertical forest, nanotube pillars). Applications of SWNT in different fields are also described in this report. In relation to this project five students have graduated (3 PhD and 2 MS) and 35 papers have been published.

  19. Analysis of nanoparticles with an optical sensor based on carbon nanotubes

    Science.gov (United States)

    Stäb, J.; Furin, D.; Fechner, P.; Proll, G.; Soriano-Dotor, L. M.; Ruiz-Palomero, C.; Valcárcel, M.; Gauglitz, G.

    2017-05-01

    Nanomaterials play an important role in science and in every day products. This is due to their varied and specific properties, whereby especially engineered nanoparticles (ENPs) have shown various beneficial properties for a wide range of application in consumables (e.g. cosmetics, drinks, food and food packaging). Silver nanoparticles for instance are hidden in meat packaging materials or in deodorants. Reasons for this can be found in the antibacterial effect of silver, which leads to high applicability in consumer products. However, ENPs are under permanent discussion due to their unforeseen hazards and an unknown disposition in living organisms and the environment. So far, there is a lack of methods, which allows for the fast and effective characterization and quantification of such nanoparticles in complex matrices (e.g. creams, fruit juice), since matrix components can impede a specific detection of the analyte. It was the objective of project INSTANT to address this topic and compose a method to detect nanoparticles as a first step. Therefore, the development of a sensor system with an upstream sample preparation for the characterization and quantification of specific nanoparticles in complex matrices using a label free optical sensor array in combination with novel recognition elements was developed. The promising optical technology iRIfS (imaging reflectometric interference sensor) was used for this purpose. As a recognition element, functionalized carbon nanotubes can be effectively used. Owing to their excellent electronical, mechanical and chemical properties, CNTs have already been used for extracting ENPs from complex matrices as sorbent material by filtration. After successful immobilization of CNTs on microscope glass slides e.g. the detection of stabilized silver nanoparticles extracted by a sample preparation unit using the iRIfS technology was performed.

  20. Importance of the alignment of polar π conjugated molecules inside carbon nanotubes in determining second-order non-linear optical properties.

    Science.gov (United States)

    Yumura, Takashi; Yamamoto, Wataru

    2017-09-20

    We employed density functional theory (DFT) calculations with dispersion corrections to investigate energetically preferred alignments of certain p,p'-dimethylaminonitrostilbene (DANS) molecules inside an armchair (m,m) carbon nanotube (n × DANS@(m,m)), where the number of inner molecules (n) is no greater than 3. Here, three types of alignments of DANS are considered: a linear alignment in a parallel fashion and stacking alignments in parallel and antiparallel fashions. According to DFT calculations, a threshold tube diameter for containing DANS molecules in linear or stacking alignments was found to be approximately 1.0 nm. Nanotubes with diameters smaller than 1.0 nm result in the selective formation of linearly aligned DANS molecules due to strong confinement effects within the nanotubes. By contrast, larger diameter nanotubes allow DANS molecules to align in a stacking and linear fashion. The type of alignment adopted by the DANS molecules inside a nanotube is responsible for their second-order non-linear optical properties represented by their static hyperpolarizability (β 0 values). In fact, we computed β 0 values of DANS assemblies taken from optimized n × DANS@(m,m) structures, and their values were compared with those of a single DANS molecule. DFT calculations showed that β 0 values of DANS molecules depend on their alignment, which decrease in the following order: linear alignment > parallel stacking alignment > antiparallel stacking alignment. In particular, a linear alignment has a β 0 value more significant than that of the same number of isolated molecules. Therefore, the linear alignment of DANS molecules, which is only allowed inside smaller diameter nanotubes, can strongly enhance their second-order non-linear optical properties. Since the nanotube confinement determines the alignment of DANS molecules, a restricted nanospace can be utilized to control their second-order non-linear optical properties. These DFT findings can assist in the

  1. Gas phase synthesis of non-bundled, small diameter single-walled carbon nanotubes with near-armchair chiralities

    Energy Technology Data Exchange (ETDEWEB)

    Mustonen, K.; Laiho, P.; Kaskela, A.; Zhu, Z.; Reynaud, O.; Houbenov, N.; Tian, Y.; Jiang, H.; Kauppinen, E. I., E-mail: esko.kauppinen@aalto.fi [Department of Applied Physics, Aalto University School of Science, P.O. Box 15100, FI-00076 Aalto (Finland); Susi, T. [Faculty of Physics, University of Vienna, Boltzmanngasse 5, A-1090 Vienna (Austria); Nasibulin, A. G. [Department of Applied Physics, Aalto University School of Science, P.O. Box 15100, FI-00076 Aalto (Finland); Skolkovo Institute of Science and Technology, Nobel str. 3, 143026 (Russian Federation); Saint-Petersburg State Polytechnical University, 29 Polytechniheskaya st., St. Petersburg, 195251 (Russian Federation)

    2015-07-06

    We present a floating catalyst synthesis route for individual, i.e., non-bundled, small diameter single-walled carbon nanotubes (SWCNTs) with a narrow chiral angle distribution peaking at high chiralities near the armchair species. An ex situ spark discharge generator was used to form iron particles with geometric number mean diameters of 3–4 nm and fed into a laminar flow chemical vapour deposition reactor for the continuous synthesis of long and high-quality SWCNTs from ambient pressure carbon monoxide. The intensity ratio of G/D peaks in Raman spectra up to 48 and mean tube lengths up to 4 μm were observed. The chiral distributions, as directly determined by electron diffraction in the transmission electron microscope, clustered around the (n,m) indices (7,6), (8,6), (8,7), and (9,6), with up to 70% of tubes having chiral angles over 20°. The mean diameter of SWCNTs was reduced from 1.10 to 1.04 nm by decreasing the growth temperature from 880 to 750 °C, which simultaneously increased the fraction of semiconducting tubes from 67% to 80%. Limiting the nanotube gas phase number concentration to ∼10{sup 5 }cm{sup −3} prevented nanotube bundle formation that is due to collisions induced by Brownian diffusion. Up to 80% of 500 as-deposited tubes observed by atomic force and transmission electron microscopy were individual. Transparent conducting films deposited from these SWCNTs exhibited record low sheet resistances of 63 Ω/□ at 90% transparency for 550 nm light.

  2. The DNA hybridization assay using single-walled carbon nanotubes as ultrasensitive, long-term optical labels

    International Nuclear Information System (INIS)

    Hwang, Eung-Soo; Cao, Chengfan; Hong, Sanghyun; Jung, Hye-Jin; Cha, Chang-Yong; Choi, Jae-Boong; Kim, Young-Jin; Baik, Seunghyun

    2006-01-01

    Single walled carbon nanotubes (SWNTs) exhibit strong Raman signals as well as fluorescence emissions in the near infrared region. Such signals do not blink or photobleach under prolonged excitation, which is an advantage in optical nano-biomarker applications. In this paper, we present single-stranded DNA conjugated SWNT probes to locate a particular sequence of DNA within a complex genome. Chromosomal DNAs of human fibroblasts and Escherichia coli are used as a target and a control, respectively. Southern blotting, which uses photostable Raman signals of nanotubes instead of fluorescent dyes, demonstrates excellent sensitivity and specificity of the probes. The results show that SWNTs may be used as generic nano-biomarkers for the precise detection of specific kinds of genes

  3. Spectral tuning of optical coupling between air-mode nanobeam cavities and individual carbon nanotubes

    Science.gov (United States)

    Machiya, Hidenori; Uda, Takushi; Ishii, Akihiro; Kato, Yuichiro K.

    Air-mode nanobeam cavities allow for high efficiency coupling to air-suspended carbon nanotubes due to their unique mode profile that has large electric fields in air. Here we utilize heating-induced energy shift of carbon nanotube emission to investigate the cavity quantum electrodynamics effects. In particular, we use laser-induced heating which causes a large blue-shift of the nanotube photoluminescence as the excitation power is increased. Combined with a slight red-shift of the cavity mode at high powers, detuning of nanotube emission from the cavity can be controlled. We estimate the spontaneous emission coupling factor β at different spectral overlaps and find an increase of β factor at small detunings, which is consistent with Purcell enhancement of nanotube emission. Work supported by JSPS (KAKENHI JP26610080, JP16K13613), Asahi Glass Foundation, Canon Foundation, and MEXT (Photon Frontier Network Program, Nanotechnology Platform).

  4. Hydrothermal synthesis of cobalt sulfide nanotubes: The size control and its application in supercapacitors

    Science.gov (United States)

    Wan, Houzhao; Ji, Xiao; Jiang, Jianjun; Yu, Jingwen; Miao, Ling; Zhang, Li; Bie, Shaowei; Chen, Haichao; Ruan, Yunjun

    2013-12-01

    Cobalt sulfide nanotubes are synthesized by hydrothermal method. The precursor is characterized by XRD, FTIR and SEM. We study the influence of temperature on the evolution of this special coarse shape nanostructure and analyze relationship between the sizes of cobalt sulfide nanotubes and the capacitive properties of active materials. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) are used to study the effects of microstructure and morphology of the samples on their capacitance and conductivity. The specific capacitance of cobalt sulfide nanotubes (obtained in 80 °C) electrode exhibits a capacitance of 285 F g-1 at the current density of 0.5 A g-1 as well as rather good cycling stability. Moreover, during the cycling process, the coulombic efficiency remains 99%. The as-prepared cobalt sulfide nanotubes electrode exhibits excellent electrochemical performance as electrode materials for supercapacitors.

  5. Synthesis of carbon nanotube-TiO(2) nanotubular material for reversible hydrogen storage.

    Science.gov (United States)

    Mishra, Amrita; Banerjee, Subarna; Mohapatra, Susanta K; Graeve, Olivia A; Misra, Mano

    2008-11-05

    A material consisting of multi-walled carbon nanotubes (MWCNTs) and larger titania (TiO(2)) nanotube arrays has been produced and found to be efficient for reversible hydrogen (H(2)) storage. The TiO(2) nanotube arrays (diameter ∼60 nm and length ∼2-3 µm) are grown on a Ti substrate, and MWCNTs a few µm in length and ∼30-60 nm in diameter are grown inside these TiO(2) nanotubes using chemical vapor deposition with cobalt as a catalyst. The resulting material has been used in H(2) storage experiments based on a volumetric method using the pressure, composition, and temperature relationship of the storage media. This material can store up to 2.5 wt% of H(2) at 77 K under 25 bar with more than 90% reversibility.

  6. Synthesis of carbon nanotube-TiO2 nanotubular material for reversible hydrogen storage

    International Nuclear Information System (INIS)

    Mishra, Amrita; Banerjee, Subarna; Mohapatra, Susanta K; Graeve, Olivia A; Misra, Mano

    2008-01-01

    A material consisting of multi-walled carbon nanotubes (MWCNTs) and larger titania (TiO 2 ) nanotube arrays has been produced and found to be efficient for reversible hydrogen (H 2 ) storage. The TiO 2 nanotube arrays (diameter ∼60 nm and length ∼2-3 μm) are grown on a Ti substrate, and MWCNTs a few μm in length and ∼30-60 nm in diameter are grown inside these TiO 2 nanotubes using chemical vapor deposition with cobalt as a catalyst. The resulting material has been used in H 2 storage experiments based on a volumetric method using the pressure, composition, and temperature relationship of the storage media. This material can store up to 2.5 wt% of H 2 at 77 K under 25 bar with more than 90% reversibility.

  7. Synthesis of Large Arrays of Well-Aligned Carbon Nanotubes on Glass

    Energy Technology Data Exchange (ETDEWEB)

    Bush, P. Siegal, M.P.; Huang, Z.P.; Provencio, P.N.; Ren, Z.F.; Wang, J.H.; Xu, J.W.

    1998-11-10

    Free-standing aligned carbon nanotubes have previously been grown above 7000C on mesoporous silica embedded with iron nanoparticles. Here, carbon nanotubes aligned over areas up to several square centimeters were grown on nickel-coated glass below 666oC by plasma-enhanced hot filament chemical vapor deposition. Acetylene (C2H2) gas was used as the carbon source and ammonia (NH3) gas was used as a catalyst and dilution gas. Nanotubes with controllable diameters from 20 to 400 nanometers and lengths from 0.1 to 50 micrometers were obtained. Using this method, large panels of aligned carbon nanotubes can be made under conditions that are suitable for device fabrication.

  8. 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.

  9. New carbon materials. Recent advances in the synthesis of fullerenes and carbon nanotubes; Shin tanso zairyo. Furaren, kabon nanochubu no gosei no saikin no shinpo

    Energy Technology Data Exchange (ETDEWEB)

    Yumura, M [National Inst. of Materials and Chemical Research, Tsukuba (Japan)

    1996-01-01

    Arc synthesis method, which is now the center for the synthesis of new carbon compounds such as carbon nanocapsules and carbon nanotubes, is introduced together with its current status. Many new carbon compounds are synthesized by DC arc discharge heating method (arc discharge method) in which a graphite bar is used as the electrode. C70 and higher order fullerenes having larger carbon numbers are found one after another in the soot produced by the arc discharge method, and the structures of C76, C78, C84, C90, C94, and others have been clarified. It is considered in the arc discharge method that the processes of a large amount of carbon evaporation by high temperature and the succeeding quenching cause to produce various kinds of new carbon compounds. In connection with other synthesis methods, synthesis of fullerenes by incomplete combustion, synthesis of nanotubes by the vapor phase thermal decomposition method, and the synthesis of nanotubes using casting molds are discussed. 24 refs., 6 figs.

  10. Synthesis of gold nano-catalysts supported on carbon nanotubes by using electroless plating technique

    International Nuclear Information System (INIS)

    Ma Xicheng; Li Xia; Lun Ning; Wen Shulin

    2006-01-01

    Gold nanoparticles supported on carbon nanotubes were prepared by using electroless plating technique. High-resolution transmission electron microscopy (HRTEM) has shown that spherical gold nanoparticles were homogeneously dispersed on the surfaces of the carbon nanotubes with a distribution of particle sizes sharply at around 3-4 nm in diameter. The results presented in this work will probably provide new catalysts with better performances

  11. Synthesis of Photochromic Oligophenylenimines: Optical and Computational Studies

    Directory of Open Access Journals (Sweden)

    Armando I. Martínez Pérez

    2015-03-01

    Full Text Available Phenyleneimine oligomers 4,4'-(((1E,1'E-(((1E,1'E-(1,4-phenylenebis-(azanylylidenebis(methanylylidenebis(2,5-bis(octyloxy-4,1-phenylenebis(methanylyl-idene-bis(azanylylidenedianiline (OIC1MS and 7,7'-(((1E,1'E-(((1E,1'E-((9H-fluorene-2,7-diylbis(azanylylidenebis(methanylylidenebis(2,5-bis(octyloxy-4,1phenylenebis- (methanylylidenebis(azanylylidenebis(9H-fluoren-2-amine (OIC2MS were prepared by means of conventional and mechanochemical synthesis and characterized by FT-IR, 1H- and 13C-NMR techniques. The optical properties of the compounds were studied in solution by using UV-visible spectroscopy, and the optical effects were analyzed as a function of solvent. The results show that OIC2MS exhibits interesting photochromic properties. Furthermore, the structural and electronic properties of the compounds were analyzed by TD-DFT. It was found that the mechanosynthesis is an efficient method for the synthesis of both tetraimines.

  12. Rapid synthesis of Co, Ni co-doped ZnO nanoparticles: Optical and electrochemical properties

    Energy Technology Data Exchange (ETDEWEB)

    Romeiro, Fernanda C.; Marinho, Juliane Z.; Lemos, Samantha C.S. [Instituto de Química, Universidade Federal de Uberlândia, 38400-902 Uberlândia, MG (Brazil); Moura, Ana P. de [LIEC, Instituto de Química, Universidade Estadual Paulista, 14800-900 Araraquara, SP (Brazil); Freire, Poliana G. [Instituto de Química, Universidade Federal de Uberlândia, 38400-902 Uberlândia, MG (Brazil); Silva, Luis F. da; Longo, Elson [LIEC, Instituto de Química, Universidade Estadual Paulista, 14800-900 Araraquara, SP (Brazil); Munoz, Rodrigo A.A. [Instituto de Química, Universidade Federal de Uberlândia, 38400-902 Uberlândia, MG (Brazil); Lima, Renata C., E-mail: rclima@iqufu.ufu.br [Instituto de Química, Universidade Federal de Uberlândia, 38400-902 Uberlândia, MG (Brazil)

    2015-10-15

    We report for the first time a rapid preparation of Zn{sub 1−2x}Co{sub x}Ni{sub x}O nanoparticles via a versatile and environmentally friendly route, microwave-assisted hydrothermal (MAH) method. The Co, Ni co-doped ZnO nanoparticles present an effect on photoluminescence and electrochemical properties, exhibiting excellent electrocatalytic performance compared to undoped ZnO sample. Photoluminescence spectroscopy measurements indicated the reduction of the green–orange–red visible emission region after adding Co and Ni ions, revealing the formation of alternative pathways for the generated recombination. The presence of these metallic ions into ZnO creates different defects, contributing to a local structural disorder, as revealed by Raman spectra. Electrochemical experiments revealed that the electrocatalytic oxidation of dopamine on ZnO attached to multi-walled carbon nanotubes improved significantly in the Co, Ni co-doped ZnO samples when compared to pure ZnO. - Graphical abstract: Rapid synthesis of Co, Ni co-doped ZnO nanoparticles: optical and electrochemical properties. Co, Ni co-doped ZnO hexagonal nanoparticles with optical and electrocatalytic properties were successfully prepared for the first time using a microwave hydrothermal method at mild conditions. - Highlights: • Co{sup 2+} and Ni{sup 2+} into ZnO lattice obtained a mild and environmentally friendly process. • The heating method strongly influences in the growth and shape of the particles. • Short-range defects generated by the ions insertion affects the photoluminescence. • Doped ZnO nanoparticles improve the electrocatalytic properties of pure oxide.

  13. Fast synthesis of multilayer carbon nanotubes from camphor oil as an energy storage material.

    Science.gov (United States)

    TermehYousefi, Amin; Bagheri, Samira; Shinji, Kawasaki; Rouhi, Jalal; Rusop Mahmood, Mohamad; Ikeda, Shoichiro

    2014-01-01

    Among the wide range of renewable energy sources, the ever-increasing demand for electricity storage represents an emerging challenge. Utilizing carbon nanotubes (CNTs) for energy storage is closely being scrutinized due to the promising performance on top of their extraordinary features. In this work, well-aligned multilayer carbon nanotubes were successfully synthesized on a porous silicon (PSi) substrate in a fast process using renewable natural essential oil via chemical vapor deposition (CVD). Considering the influx of vaporized multilayer vertical carbon nanotubes (MVCNTs) to the PSi, the diameter distribution increased as the flow rate decreased in the reactor. Raman spectroscopy results indicated that the crystalline quality of the carbon nanotubes structure exhibits no major variation despite changes in the flow rate. Fourier transform infrared (FT-IR) spectra confirmed the hexagonal structure of the carbon nanotubes because of the presence of a peak corresponding to the carbon double bond. Field emission scanning electron microscopy (FESEM) images showed multilayer nanotubes, each with different diameters with long and straight multiwall tubes. Moreover, the temperature programmed desorption (TPD) method has been used to analyze the hydrogen storage properties of MVCNTs, which indicates that hydrogen adsorption sites exist on the synthesized multilayer CNTs.

  14. Fast Synthesis of Multilayer Carbon Nanotubes from Camphor Oil as an Energy Storage Material

    Directory of Open Access Journals (Sweden)

    Amin TermehYousefi

    2014-01-01

    Full Text Available Among the wide range of renewable energy sources, the ever-increasing demand for electricity storage represents an emerging challenge. Utilizing carbon nanotubes (CNTs for energy storage is closely being scrutinized due to the promising performance on top of their extraordinary features. In this work, well-aligned multilayer carbon nanotubes were successfully synthesized on a porous silicon (PSi substrate in a fast process using renewable natural essential oil via chemical vapor deposition (CVD. Considering the influx of vaporized multilayer vertical carbon nanotubes (MVCNTs to the PSi, the diameter distribution increased as the flow rate decreased in the reactor. Raman spectroscopy results indicated that the crystalline quality of the carbon nanotubes structure exhibits no major variation despite changes in the flow rate. Fourier transform infrared (FT-IR spectra confirmed the hexagonal structure of the carbon nanotubes because of the presence of a peak corresponding to the carbon double bond. Field emission scanning electron microscopy (FESEM images showed multilayer nanotubes, each with different diameters with long and straight multiwall tubes. Moreover, the temperature programmed desorption (TPD method has been used to analyze the hydrogen storage properties of MVCNTs, which indicates that hydrogen adsorption sites exist on the synthesized multilayer CNTs.

  15. Fast Synthesis of Multilayer Carbon Nanotubes from Camphor Oil as an Energy Storage Material

    Science.gov (United States)

    TermehYousefi, Amin; Bagheri, Samira; Shinji, Kawasaki; Rouhi, Jalal; Rusop Mahmood, Mohamad; Ikeda, Shoichiro

    2014-01-01

    Among the wide range of renewable energy sources, the ever-increasing demand for electricity storage represents an emerging challenge. Utilizing carbon nanotubes (CNTs) for energy storage is closely being scrutinized due to the promising performance on top of their extraordinary features. In this work, well-aligned multilayer carbon nanotubes were successfully synthesized on a porous silicon (PSi) substrate in a fast process using renewable natural essential oil via chemical vapor deposition (CVD). Considering the influx of vaporized multilayer vertical carbon nanotubes (MVCNTs) to the PSi, the diameter distribution increased as the flow rate decreased in the reactor. Raman spectroscopy results indicated that the crystalline quality of the carbon nanotubes structure exhibits no major variation despite changes in the flow rate. Fourier transform infrared (FT-IR) spectra confirmed the hexagonal structure of the carbon nanotubes because of the presence of a peak corresponding to the carbon double bond. Field emission scanning electron microscopy (FESEM) images showed multilayer nanotubes, each with different diameters with long and straight multiwall tubes. Moreover, the temperature programmed desorption (TPD) method has been used to analyze the hydrogen storage properties of MVCNTs, which indicates that hydrogen adsorption sites exist on the synthesized multilayer CNTs. PMID:25258714

  16. 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.

  17. TiO{sub 2}-based nanotubes modified with nickel: synthesis, properties, and improved photocatalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Qamar, M; Ganguli, A K [Department of Chemistry, Indian Institute of Technology, Hauz Khas, New Delhi 110016 (India); Kim, S J, E-mail: sjkim1@sejong.ac.k, E-mail: ashok@chemistry.iitd.ac.i [Department of Nano Science and Technology, Sejong Advanced Institute of Nano Technologies, Sejong University, 98, Gunja-dong, Gwangjin-gu, Seoul 143-747 (Korea, Republic of)

    2009-11-11

    Titanate nanotubes containing 2.5 wt% Ni were synthesized from TiO{sub 2} sol using alkali hydrothermal treatment followed by a simple ion-exchange process. The changes in phase, shape and morphology, surface area, and photocatalytic activity of these nanotubes have been explored as a function of calcination temperature. The samples were characterized using standard techniques, including x-ray diffraction, transmission electron microscopy, scanning electron microscopy, inductively coupled plasma spectrometry, energy dispersive x-ray spectroscopy, and Brauner-Emmett-Teller surface area analysis. The study revealed that the titanate phase containing Ni ions can be converted to the anatase phase after certain heat treatments but, at the same time, the tubular morphology was partially lost. Investigation of photocatalytic properties demonstrated that the as-prepared Ni-titanate nanotubes were photocatalytically inactive, but when heated at temperatures below 500 {sup 0}C their activity was significantly enhanced with the change in phase. The calcined nanotube samples carrying nickel ion showed better photocatalytic activity than calcined nanotube samples containing protons. The hydrogen adsorption capacity of these titanates has also been measured, and it was found that Ni-titanate nanotubes can adsorb more hydrogen than its counterpart Na-titanate.

  18. Co-doping as a tool for tuning the optical properties of singlewalled carbon nanotubes: A first principles study

    Science.gov (United States)

    Sharma, Deepa; Jaggi, Neena

    2017-07-01

    This paper presents a first principles study on the effect of co-doping on various optical spectra of a zigzag single-walled carbon nanotube (SWCNT). Optical spectra of a pristine SWCNT, SWCNT co-doped with Aluminum (Al) & Phosphorus (P) and another one co-doped with Al, P and Nitrogen (N) have been calculated using density functional theory (DFT).The theory has been implemented using the Cambridge sequential total energy package (CASTEP) code available as a userfriendly module with the software 'Material Studio'. Polarized and unpolarized light as well as light through polycrystalline media have been considered. The dependence of various spectra on the status of incident light presents a clear evidence of anisotropicity in the optical properties. Analysis of the simulated spectra involves calculation and comparison of different optical properties like dielectric function, reflectivity, refractive index, conductivity and loss function for the pristine and co-doped SWCNTs. Noticeable variations are observed in the optical properties on simultaneously doping the SWCNT with Al and P and then further introducing N atom into the structure so that it can be concluded that co-doping (simultaneous doping with different combinations of dopants) can be evolved as a novel and effective tool for tailoring the optical properties of SWCNTs as per the requirements while designing an optical device. It will prove to be highly significant for effective designing of SWCNT based sensitive optical devices for a variety of technological applications.

  19. En route to controlled catalytic CVD synthesis of densely packed and vertically aligned nitrogen-doped carbon nanotube arrays

    Directory of Open Access Journals (Sweden)

    Slawomir Boncel

    2014-03-01

    Full Text Available The catalytic chemical vapour deposition (c-CVD technique was applied in the synthesis of vertically aligned arrays of nitrogen-doped carbon nanotubes (N-CNTs. A mixture of toluene (main carbon source, pyrazine (1,4-diazine, nitrogen source and ferrocene (catalyst precursor was used as the injection feedstock. To optimize conditions for growing the most dense and aligned N-CNT arrays, we investigated the influence of key parameters, i.e., growth temperature (660, 760 and 860 °C, composition of the feedstock and time of growth, on morphology and properties of N-CNTs. The presence of nitrogen species in the hot zone of the quartz reactor decreased the growth rate of N-CNTs down to about one twentieth compared to the growth rate of multi-wall CNTs (MWCNTs. As revealed by electron microscopy studies (SEM, TEM, the individual N-CNTs (half as thick as MWCNTs grown under the optimal conditions were characterized by a superior straightness of the outer walls, which translated into a high alignment of dense nanotube arrays, i.e., 5 × 108 nanotubes per mm2 (100 times more than for MWCNTs grown in the absence of nitrogen precursor. In turn, the internal crystallographic order of the N-CNTs was found to be of a ‘bamboo’-like or ‘membrane’-like (multi-compartmental structure morphology. The nitrogen content in the nanotube products, which ranged from 0.0 to 3.0 wt %, was controlled through the concentration of pyrazine in the feedstock. Moreover, as revealed by Raman/FT-IR spectroscopy, the incorporation of nitrogen atoms into the nanotube walls was found to be proportional to the number of deviations from the sp2-hybridisation of graphene C-atoms. As studied by XRD, the temperature and the [pyrazine]/[ferrocene] ratio in the feedstock affected the composition of the catalyst particles, and hence changed the growth mechanism of individual N-CNTs into a ‘mixed base-and-tip’ (primarily of the base-type type as compared to the purely

  20. En route to controlled catalytic CVD synthesis of densely packed and vertically aligned nitrogen-doped carbon nanotube arrays.

    Science.gov (United States)

    Boncel, Slawomir; Pattinson, Sebastian W; Geiser, Valérie; Shaffer, Milo S P; Koziol, Krzysztof K K

    2014-01-01

    The catalytic chemical vapour deposition (c-CVD) technique was applied in the synthesis of vertically aligned arrays of nitrogen-doped carbon nanotubes (N-CNTs). A mixture of toluene (main carbon source), pyrazine (1,4-diazine, nitrogen source) and ferrocene (catalyst precursor) was used as the injection feedstock. To optimize conditions for growing the most dense and aligned N-CNT arrays, we investigated the influence of key parameters, i.e., growth temperature (660, 760 and 860 °C), composition of the feedstock and time of growth, on morphology and properties of N-CNTs. The presence of nitrogen species in the hot zone of the quartz reactor decreased the growth rate of N-CNTs down to about one twentieth compared to the growth rate of multi-wall CNTs (MWCNTs). As revealed by electron microscopy studies (SEM, TEM), the individual N-CNTs (half as thick as MWCNTs) grown under the optimal conditions were characterized by a superior straightness of the outer walls, which translated into a high alignment of dense nanotube arrays, i.e., 5 × 10(8) nanotubes per mm(2) (100 times more than for MWCNTs grown in the absence of nitrogen precursor). In turn, the internal crystallographic order of the N-CNTs was found to be of a 'bamboo'-like or 'membrane'-like (multi-compartmental structure) morphology. The nitrogen content in the nanotube products, which ranged from 0.0 to 3.0 wt %, was controlled through the concentration of pyrazine in the feedstock. Moreover, as revealed by Raman/FT-IR spectroscopy, the incorporation of nitrogen atoms into the nanotube walls was found to be proportional to the number of deviations from the sp(2)-hybridisation of graphene C-atoms. As studied by XRD, the temperature and the [pyrazine]/[ferrocene] ratio in the feedstock affected the composition of the catalyst particles, and hence changed the growth mechanism of individual N-CNTs into a 'mixed base-and-tip' (primarily of the base-type) type as compared to the purely 'base'-type for undoped

  1. Single crystalline Co3O4: Synthesis and optical properties

    International Nuclear Information System (INIS)

    Hosny, Nasser Mohammed

    2014-01-01

    Crystals of Co 3 O 4 have been prepared from thermal decomposition of molecular precursors derived from salicylic acid and cobalt (II) acetate or chloride at 500 °C. A cubic phase Co 3 O 4 micro- and nanocrystals have been obtained. The as-synthesized products were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM). The images of electron microscopes showed octahedral crystals of Co 3 O 4 . The volume and polarizability of the optimized structures of molecular precursors have been calculated and related to the particle size. The optical band gap of the obtained crystals has been measured. The results indicated two optical band gaps with values 2.65 and 2.95 eV for (E g1 ) (E g2 ), respectively. - Highlights: • Synthesis of Co 3 O 4 nanocrystals by decomposition of cobalt salicylic acid precursor. • Characterization of the isolated nanocrystals by using XRD, SEM and HRTEM. • The optical band gap has been measured

  2. Fiber-optic anemometer based on single-walled carbon nanotube coated tilted fiber Bragg grating.

    Science.gov (United States)

    Zhang, Yang; Wang, Fang; Liu, Zigeng; Duan, Zhihui; Cui, Wenli; Han, Jie; Gu, Yiying; Wu, Zhenlin; Jing, Zhenguo; Sun, Changsen; Peng, Wei

    2017-10-02

    In this work, a novel and simple optical fiber hot-wire anemometer based on single-walled carbon nanotubes (SWCNTs) coated tilted fiber Bragg grating (TFBG) is proposed and demonstrated. For the hot-wire wind speed sensor design, TFBG is an ideal in-fiber sensing structure due to its unique features. It is utilized as both light coupling and temperature sensing element without using any geometry-modified or uncommon fiber, which simplifies the sensor structure. To further enhance the thermal conversion capability, SWCNTs are coated on the surface of the TFBG instead of traditional metallic materials, which have excellent thermal characteristics. When a laser light is pumped into the sensor, the pump light propagating in the core will be easily coupled into cladding of the fiber via the TFBG and strongly absorbed by the SWCNTs thin film. This absorption acts like a hot-wire raising the local temperature of the fiber, which is accurately detected by the TFBG resonance shift. In the experiments, the sensor's performances were investigated and controlled by adjusting the inherent angle of the TFBG, the thickness of SWCNTs film, and the input power of the pump laser. It was demonstrated that the developed anemometer exhibited significant light absorption efficiency up to 93%, and the maximum temperature of the local area on the fiber was heated up to 146.1°C under the relatively low pump power of 97.76 mW. The sensitivity of -0.3667 nm/(m/s) at wind speed of 1.0 m/s was measured with the selected 12° TFBG and 1.6 μm film.

  3. Microstructural and optical properties of nanocrystalline ZnO deposited onto vertically aligned carbon nanotubes by physical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Borkar, Tushar [Department of Materials Science and Engineering and Center for Advanced Research and Technology, University of North Texas, Denton 76203 (United States); Chang, Won Seok [Korea Institute of Machinery and Materials, 104 Sinseongno, Yuseong-gu, Daejeon 305-343 (Korea, Republic of); Hwang, Jun Yeon, E-mail: Junyeon.Hwang@kist.re.kr [Department of Materials Science and Engineering and Center for Advanced Research and Technology, University of North Texas, Denton 76203 (United States); Institute of Advanced Composite Materials, Korea Institute of Science and Technology, Jeonbuk 565-902 (Korea, Republic of); Shepherd, Nigel D.; Banerjee, Rajarshi [Department of Materials Science and Engineering and Center for Advanced Research and Technology, University of North Texas, Denton 76203 (United States)

    2012-10-15

    Nanocrystalline ZnO films with thicknesses of 5 nm, 10 nm, 20 nm, and 50 nm were deposited via magnetron sputtering onto the surface of vertically aligned multi-walled carbon nanotubes (MWCNTs). The ZnO/CNTs heterostructures were characterized by scanning electron microscopy, high resolution transmission electron microscopy, and X-ray diffraction studies. No structural degradation of the CNTs was observed and photoluminescence (PL) measurements of the nanostructured ZnO layers show that the optical properties of these films are typical of ZnO deposited at low temperatures. The results indicate that magnetron sputtering is a viable technique for growing heterostructures and depositing functional layers onto CNTs.

  4. Systematic study on synthesis and purification of double-walled carbon nanotubes synthesized via CVD

    Science.gov (United States)

    Jedrzejewska, A.; Kalenczuk, R. J.; Mijowska, E.

    2011-12-01

    Carbon nanotubes have unique properties, such as thermal and electrical conductance, which could be useful in the fields of aerospace, microelectronics and biotechnology. However, these properties may vary widely depending on the dimensions, uniformity and purity of the nanotube. Nanotube samples typically contain a significant percentage of more allotropes forms of carbon as well as metal particles left over from catalysts used in manufacturing. Purity characterization of double-walled carbon nanotubes (DWCNTs) is an increasingly popular topic in the field of carbon nanotechnology. In this study, DWCNTs were synthesized in a catalytic reaction, using Fe:MgO as catalyst and methane or methane/ethanol as carbon feedstock for chemical vapor deposition (CVD). The addition of ethanol as carbon feedstock allowed to investigate the influence of oxygen on the sample quality. The purification of the as-produced material from the metallic particles and the catalyst support was performed by sonication in an acid solution. The influence of the duration of the acid treatment using ultrasound on the sample purity was investigated, and the optimal value of this parameter was found. Transmission electron microscopy (TEM) images confirmed the removal of impurities and served to elucidate the morphology of the samples. The purity of carbon nanotubes was analyzed using thermal gravimetric analysis (TGA). The Raman spectra of the samples, as a measure of the concentration of defects, were also reported.

  5. The facile synthesis of hierarchical NiCoO2 nanotubes comprised ultrathin nanosheets for supercapacitors

    Science.gov (United States)

    Xu, Xin; Zhou, Han; Ding, Shujiang; Li, Jun; Li, Beibei; Yu, Demei

    2014-12-01

    Hierarchical NiCoO2 nanosheets nanotubes are successfully prepared by a mild solution method based on the template of polymeric nanotubes (PNT) followed by a thermal annealing treatment. The microstructure and chemical composition of NiCoO2 nanosheets nanotubes are characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET) analyzer, X-ray diffraction (XRD) and Thermogravimetric analysis (TGA). When evaluated as an electrode material for supercapacitors, the results of electrochemical test show that the unique NiCoO2 nanosheets nanotubes exhibit relatively high specific capacitance of 1468, 1352, 1233, 1178, 1020 and 672 F g-1 at the discharge current densities of 2, 4, 8, 10, 20 and 40 A g-1, respectively. They also reveal an excellent cycling stability of 99.2% retention after 3000 cycles at 10 A g-1. The smart nanostructures of the NiCoO2 nanosheets nanotubes make a prominent contribution to the excellent electrochemical performance.

  6. Synthesis of Stacked-Cup Carbon Nanotubes in a Metal Free Low Temperature System

    Science.gov (United States)

    Kimura, Yuki; Nuth, Joseph A.; Johnson, Natasha M.; Farmer, Kevin D.; Roberts, Kenneth P.; Hussaini, Syed R.

    2011-01-01

    Stacked-cup carbon nanotubes were formed by either Fischer-Tropsch type or Haber Bosch type reactions in a metal free system. Graphite particles were used as the catalyst. The samples were heated at 600 C in a gas mixture of CO 75 Torr, N2 75 Torr and H2 550 Torr for three days. Trans mission electron microscope analysis of the catalyst surface at the completion of the experiment recognized the growth of nanotubes. They were 10-50 nm in diameter and approximately 1 micrometer in length. They had a hollow channel of 5-20 nm in the center. The nanotubes may have grown on graphite surfaces by the CO disproportionation reaction and the surface tension of the carbon nucleus may have determined the diameter. Although, generally, the diameter of a carbon nanotube depends on the size of the cataly1ic particles, the diameter of the nanotubes on graphite particles was independent of the particle size and significantly confined within a narrow range compared with that produced using catalytic amorphous iron-silicate nanoparticles. Therefore, they must have an unknown formation process that is different than the generally accepted mechanism.

  7. Synthesis and mechanical behavior of carbon nanotube-magnesium composites hybridized with nanoparticles of alumina

    International Nuclear Information System (INIS)

    Thakur, Sanjay Kumar; Srivatsan, T.S.; Gupta, Manoj

    2007-01-01

    Carbon nanotubes reinforced magnesium based composites were prepared with diligence and care using the powder metallurgy route coupled with rapid microwave sintering. Nanometer-sized particles of alumina were used to hybridize the carbon nanotubes reinforcement in the magnesium matrix so as to establish the intrinsic influence of hybridization on mechanical behavior of the resultant composite material. The yield strength, tensile strength and strain-to-failure of the carbon nanotubes-magnesium composites were found to increase with the addition of nanometer-sized alumina particles to the composite matrix. Scanning electron microscopy observations of the fracture surfaces of the samples deformed and failed in uniaxial tension revealed the presence of cleavage-like features on the fracture surface indicative of the occurrence of locally brittle fracture mechanism in the composite microstructure

  8. Solution-phase synthesis of chromium-functionalized single-walled carbon nanotubes

    KAUST Repository

    Kalinina, Irina V.

    2015-03-01

    The solution phase reactions of single-walled carbon nanotubes (SWNTs) with Cr(CO)6 and benzene-Cr(CO)3 can lead to the formation of small chromium clusters. The cluster size can be varied from less than 1 nm to about 4 nm by increasing the reaction time. TEM images suggest that the clusters are deposited predominantly on the exterior walls of the nanotubes. TGA analysis was used to obtain the Cr content and carbon to chromium ratio in the Cr-complexed SWNTs. It is suggested that the carbon nanotube benzenoid structure templates the condensation of chromium atoms and facilitates the loss of carbon monoxide leading to well defined metal clusters.

  9. Synthesis and characterization of semiconductor zinc sulfide nanotubes by soft-template method

    Institute of Scientific and Technical Information of China (English)

    Lü Ruitao; CAO Chuanbao; ZHAI Huazhang; ZHU Hesun

    2004-01-01

    ZnS nanotubes have been successfully synthesized from solutions containing a surfactant, Triton X-100 (t-octyl-(OCH2CH2)xOH, x=9, 10). X-ray diffraction (XRD), transmission electron microscope (TEM) and selected area electron diffraction (SAED) are employed to characterize the structure and morphology of as-synthesized product. XRD and SAED pattern indicate that as-obtained products consist of pure polycrystalline cubic-phase ZnS structures. TEM images reveal that most of the products are tubular structures, with diameters ranging between 37-52 nm and lengths up to 3 μm. The wall thickness of as-obtained ZnS nanotube is around 9 nm. The growth mechanism of ZnS nanotubes has also be proposed.

  10. Synthesis and characteristics of Fe-filled multi-walled carbon nanotubes for biomedical application

    Energy Technology Data Exchange (ETDEWEB)

    Moench, I [Leibniz Institute of Solid State and Materials Research Dresden, IFW-Dresden, Helmholtzstr. 20, D-01069 Dresden (Germany); Leonhardt, A [Leibniz Institute of Solid State and Materials Research Dresden, IFW-Dresden, Helmholtzstr. 20, D-01069 Dresden (Germany); Meye, A [Department of Urology, Technical University Dresden, Fetscherstrasse 74, D-01062 Dresden (Germany); Hampel, S [Leibniz Institute of Solid State and Materials Research Dresden, IFW-Dresden, Helmholtzstr. 20, D-01069 Dresden (Germany); Kozhuharova-Koseva, R [Leibniz Institute of Solid State and Materials Research Dresden, IFW-Dresden, Helmholtzstr. 20, D-01069 Dresden (Germany); Elefant, D [Leibniz Institute of Solid State and Materials Research Dresden, IFW-Dresden, Helmholtzstr. 20, D-01069 Dresden (Germany); Wirth, M P [Department of Urology, Technical University Dresden, Fetscherstrasse 74, D-01062 Dresden (Germany); Buechner, B [Leibniz Institute of Solid State and Materials Research Dresden, IFW-Dresden, Helmholtzstr. 20, D-01069 Dresden (Germany)

    2007-04-15

    Multifunctional nanocontainers can be produced based on partially filled Fe-multi walled carbon nanotubes (MWCNTs). Using thermal decomposition ferrocene filled nanotubes can be grown aligned on substrates. The encapsulated metal nanowires have diameters of 5-30 nm and a length up to few microns. They consist of single-crystalline of {alpha} and {gamma}-Fe- phases. Using heat treatment, it is possible to transform {gamma}-Fe into {alpha}-Fe. With the aid of wet chemical methods the nanotubes can be opened and additionally filled with an agent, e.g., therapeutic agents (carboplatin) or other metals (copper). Initial studies do not show a high toxicity over a period of 440 days. These materials can be used for drug delivery and hyperthermia. The specific absorption rate (SAR) is greater than 100W/(g-{alpha}-Fe) in a magnetic field of 18kA/m (f = 250kHz)

  11. Solution-phase synthesis of chromium-functionalized single-walled carbon nanotubes

    KAUST Repository

    Kalinina, Irina V.; Al-Hadeethi, Yas Fadel; Bekyarova, Elena; Zhao, Chao; Wang, Qingxiao; Zhang, Xixiang; Al-Zahrani, Ali; Al-Agel, Faisal Abdulaziz M; Al-Marzouki, Fahad M.; Haddon, Robert C.

    2015-01-01

    The solution phase reactions of single-walled carbon nanotubes (SWNTs) with Cr(CO)6 and benzene-Cr(CO)3 can lead to the formation of small chromium clusters. The cluster size can be varied from less than 1 nm to about 4 nm by increasing the reaction time. TEM images suggest that the clusters are deposited predominantly on the exterior walls of the nanotubes. TGA analysis was used to obtain the Cr content and carbon to chromium ratio in the Cr-complexed SWNTs. It is suggested that the carbon nanotube benzenoid structure templates the condensation of chromium atoms and facilitates the loss of carbon monoxide leading to well defined metal clusters.

  12. Template assisted synthesis and optical properties of gold nanoparticles.

    Science.gov (United States)

    Fodor, Petru; Lasalvia, Vincenzo

    2009-03-01

    A hybrid nanofabrication method (interference lithography + self assembly) was explored for the fabrication of arrays of gold nanoparticles. To ensure the uniformity of the nanoparticles, a template assisted synthesis was used in which the gold is electrodeposited in the pores of anodized aluminum membranes. The spacing between the pores and their ordering is controlled in the first fabrication step of the template in which laser lithography and metal deposition are used to produce aluminum films with controlled strain profiles. The diameter of the pores produced after anodizing the aluminum film in acidic solution determines the diameter of the gold particles, while their aspect ratio is controlled through the deposition time. Optical absorbance spectroscopy is used to evaluate the ability to tune the nanoparticles plasmon resonance spectra through control over their size and aspect ratio.

  13. Facile Synthesis of Novel Networked Ultralong Cobalt Sulfide Nanotubes and Its Application in Supercapacitors.

    Science.gov (United States)

    Liu, Sangui; Mao, Cuiping; Niu, Yubin; Yi, Fenglian; Hou, Junke; Lu, Shiyu; Jiang, Jian; Xu, Maowen; Li, Changming

    2015-11-25

    Ultralong cobalt sulfide (CoS(1.097)) nanotube networks are synthesized by a simple one-step solvothermal method without any surfactant or template. A possible formation mechanism for the growth processes is proposed. Owing to the hollow structure and large specific area, the novel CoS(1.097) materials present outstanding electrochemical properties. Electrochemical measurements for supercapacitors show that the as-prepared ultralong CoS(1.097) nanotube networks exhibit high specific capacity, good capacity retention, and excellent Coulombic efficiency.

  14. Microwave-assisted synthesis of carbon nanotubes from tannin, lignin, and derivatives

    Science.gov (United States)

    Viswanathan, Tito

    2014-06-17

    A method of synthesizing carbon nanotubes. In one embodiment, the method includes the steps of: (a) dissolving a first amount of a first transition-metal salt and a second amount of a second transition-metal salt in water to form a solution; (b) adding a third amount of tannin to the solution to form a mixture; (c) heating the mixture to a first temperature for a first duration of time to form a sample; and (d) subjecting the sample to a microwave radiation for a second duration of time effective to produce a plurality of carbon nanotubes.

  15. Enhancement of the optical response in a biodegradable polymer/azo-dye film by the addition of carbon nanotubes

    International Nuclear Information System (INIS)

    Costanzo, Guadalupe Díaz; Ledesma, Silvia; Ribba, Laura; Goyanes, Silvia

    2014-01-01

    A new biodegradable photoresponsive material was developed using poly(lactic acid) (PLA) as the matrix material and Disperse Orange 3 (DO3) as photoisomerizable azo-dye. It was observed that the addition of multi-walled carbon nanotubes (MWCNTs) leads to a new phenomenon consisting of an enhancement of the optical anisotropy in a wide range of temperatures. In particular, the optical anisotropy increases 100% at room temperature. Moreover, the material containing MWCNTs shows a faster optical response that is evidenced as an increase in the growth rate of optical anisotropy. Spectroscopic data is provided to study the interaction among DO3, MWCNTs and PLA. The enhancement of optical anisotropy obtained with the addition of MWCNTs was related to the glass transition temperature (T g ) of each material. Maximum optical anisotropy was obtained 15 °C below the T g for both materials. Results are interpreted in terms of the interactions among DO3, MWCNTs and PLA and the packing density of the dye into the polymer chains. (paper)

  16. Parametric study of waste chicken fat catalytic chemical vapour deposition for controlled synthesis of vertically aligned carbon nanotubes

    Science.gov (United States)

    Suriani, A. B.; Dalila, A. R.; Mohamed, A.; Rosmi, M. S.; Mamat, M. H.; Malek, M. F.; Ahmad, M. K.; Hashim, N.; Isa, I. M.; Soga, T.; Tanemura, M.

    2016-12-01

    High-quality vertically aligned carbon nanotubes (VACNTs) were synthesised using ferrocene-chicken oil mixture utilising a thermal chemical vapour deposition (TCVD) method. Reaction parameters including vaporisation temperature, catalyst concentration and synthesis time were examined for the first time to investigate their influence on the growth of VACNTs. Analysis via field emission scanning electron microscopy and micro-Raman spectroscopy revealed that the growth rate, diameter and crystallinity of VACNTs depend on the varied synthesis parameters. Vaporisation temperature of 570°C, catalyst concentration of 5.33 wt% and synthesis time of 60 min were considered as optimum parameters for the production of VACNTs from waste chicken fat. These parameters are able to produce VACNTs with small diameters in the range of 15-30 nm and good quality (ID/IG 0.39 and purity 76%) which were comparable to those synthesised using conventional carbon precursor. The low turn on and threshold fields of VACNTs synthesised using optimum parameters indicated that the VACNTs synthesised using waste chicken fat are good candidate for field electron emitter. The result of this study therefore can be used to optimise the growth and production of VACNTs from waste chicken fat in a large scale for field emission application.

  17. Preferential synthesis of (6,4) single-walled carbon nanotubes by controlling oxidation degree of Co catalyst.

    Science.gov (United States)

    Xu, Bin; Kaneko, Toshiro; Shibuta, Yasushi; Kato, Toshiaki

    2017-09-11

    Chirality-selective synthesis of single-walled carbon nanotubes (SWNTs) has been a research goal for the last two decades and is still challenging due to the difficulty in controlling the atomic structure in the one-dimensional material. Here, we develop an optimized approach for controlling the chirality of species by tuning the oxidation degree of Co catalyst. Predominant synthesis of (6,4) SWNTs is realized for the first time. The detailed mechanism is investigated through a systematic experimental study combined with first-principles calculations, revealing that the independent control of tube diameter and chiral angle achieved by changing the binding energy between SWNTs (cap and tube edge) and catalyst causes a drastic transition of chirality of SWNTs from (6,5) to (6,4). Since our approach of independently controlling the diameter and chiral angle can be applied to other chirality species, our results can be useful in achieving the on-demand synthesis of specific-chirality SWNTs.

  18. Chemical and Electrochemical Synthesis of Polypyrrole Using Carrageenan as a Dopant: Polypyrrole/Multi-Walled Carbon Nanotube Nanocomposites

    Directory of Open Access Journals (Sweden)

    Mostafizur Rahaman

    2018-06-01

    Full Text Available In this article, iota-carrageenan (IC and kappa-carrageenan (KC are used as dopants for the chemical and electrochemical synthesis of polypyrrole (PPy. The composites of chemically synthesized PPy with multi-walled carbon nanotubes (MWNTs were prepared using an in situ technique. Both the dialyzed and non-dialyzed IC and KC were used as dopants for electrochemical polymerization of pyrrole. Chemically synthesized PPy and PPy/MWNTs composites were studied by ultraviolet visible (UV-vis absorption spectra to investigate the effect of the concentration and the incorporation of MWNTs. In addition, the electrical, thermal, mechanical, and microscopic characterizations of these films were performed to examine the effect of the dopants and MWNTs on these properties, along with their surface morphology. The films of electrochemically polymerized PPy were characterized using UV-vis absorption spectra, scanning electron microscopy, and cyclic voltammetry (CV. The results were then compared with the chemical polymerized PPy.

  19. Using Converter Dust to Produce Low Cost Cementitious Composites by in situ Carbon Nanotube and Nanofiber Synthesis

    Directory of Open Access Journals (Sweden)

    Péter Ludvig

    2011-03-01

    Full Text Available Carbon nanotubes (CNTs and nanofibers (CNFs were synthesized on clinker and silica fume particles in order to create a low cost cementitious nanostructured material. The synthesis was carried out by an in situ chemical vapor deposition (CVD process using converter dust, an industrial byproduct, as iron precursor. The use of these materials reduces the cost, with the objective of application in large-scale nanostructured cement production. The resulting products were analyzed by scanning electron microscopy (SEM, transmission electron microscopy (TEM and thermogravimetric analysis (TGA and were found to be polydisperse in size and to have defective microstructure. Some enhancement in the mechanical behavior of cement mortars was observed due to the addition of these nano-size materials. The contribution of these CNTs/CNFs to the mechanical strength of mortar specimens is similar to that of high quality CNTs incorporated in mortars by physical mixture.

  20. Synthesis of Single-Walled Carbon Nanotubes: Effects of Active Metals, Catalyst Supports, and Metal Loading Percentage

    Directory of Open Access Journals (Sweden)

    Wei-Wen Liu

    2013-01-01

    Full Text Available The effects of active metals, catalyst supports, and metal loading percentage on the formation of single-walled carbon nanotubes (SWNTs were studied. In particular, iron, cobalt, and nickel were investigated for SWNTs synthesis. Iron was found to grow better-quality SWNTs compared to cobalt and nickel. To study the effect of catalyst supports, magnesium oxide, silicon oxide, and aluminium oxide were chosen for iron. Among the studied supports, MgO was identified to be a suitable support for iron as it produced SWNTs with better graphitisation determined by Raman analysis. Increasing the iron loading decreased the quality of SWNTs due to extensive agglomeration of the iron particles. Thus, lower metal loading percentage is preferred to grow better-quality SWNTs with uniform diameters.

  1. In situ synthesis of carbon nanotubes decorated with palladium nanoparticles using arc-discharge in solution method

    International Nuclear Information System (INIS)

    Bera, Debasis; Kuiry, Suresh C.; McCutchen, Matthew; Seal, Sudipta; Heinrich, Helge; Slane, Grady C.

    2004-01-01

    A unique, simple, inexpensive, and one-step synthesis route to produce carbon nanotubes (CNTs) decorated with palladium nanoparticles using a simplified dc arc-discharge in solution is reported. Zero-loss energy filtered transmission electron microscopy and scanning transmission electron microscopy confirm the presence of 3 nm palladium nanoparticles. Such palladium nanoparticles form during the reduction of palladium tetra-chloro-square-planar complex. The deconvoluted x-ray photoelectron spectroscopy envelope shows the presence of palladium on the decorated CNTs. The energy dispersive spectroscopy suggests no functionalization of atomic chlorine to the sidewall of the CNTs. The presence of dislodged graphene sheets with wavy morphology supports the formation of CNTs through the 'scroll mechanism'

  2. Using hydrocarbon as a carbon source for synthesis of carbon nanotube by electric field induced needle-pulsed plasma

    International Nuclear Information System (INIS)

    Kazemi Kia, Kaveh; Bonabi, Fahimeh

    2013-01-01

    In this work different hydrocarbons are used as the carbon source, in the production of carbon nanotubes (CNTs) and nano onions. An electric field induced needle pulse arc-discharge reactor is used. The influence of starting carbon on the synthesis of CNTs is investigated. The production efficiency is compared for Acetone, Isopropanol and Naphthalene as simple hydrocarbons. The hydrocarbons are preheated and then pretreated by electric field before being exposed to plasma. The hydrocarbon vapor is injected into plasma through a graphite spout in the cathode assembly. The pulsed plasma takes place between two graphite rods while a strong electric field has been already established alongside the electrodes. The pulse width is 0.3 μs. Mechanism of precursor decomposition is discussed by describing three forms of energy that are utilized to disintegrate the precursor molecules: thermal energy, electric field and kinetic energy of plasma. Molecular polarity of a hydrocarbon is one of the reasons for choosing carbon raw material as a precursor in an electric field induced low power pulsed-plasma. The results show that in order to obtain high quality carbon nanotubes, Acetone is preferred to Isopropanol and Naphthalene. Scanning probe microscopy techniques are used to investigate the products. - Highlights: • We synthesized CNTs (carbon nano tubes) by needle pulsed plasma. • We use different hydrocarbons as carbon source in the production of CNTs. • We investigated the influence of starting carbon on the synthesis of CNTs. • Thermal energy, electric field and kinetic energy are used to break carbon bonds. • Polar hydrocarbon molecules are more efficient than nonpolar ones in production

  3. Plasma synthesis and HPHT consolidation of BN nanoparticles, nanospheres, and nanotubes to produce nanocrystalline cubic boron nitride

    Science.gov (United States)

    Stout, Christopher

    Plasma methods offer a variety of advantages to nanomaterials synthesis. The process is robust, allowing varying particle sizes and phases to be generated simply by modifying key parameters. The work here demonstrates a novel approach to nanopowder synthesis using inductively-coupled plasma to decompose precursor, which are then quenched to produce a variety of boron nitride (BN)-phase nanoparticles, including cubic phase, along with short-range-order nanospheres (e.g., nano-onions) and BN nanotubes. Cubic BN (c-BN) powders can be generated through direct deposition onto a chilled substrate. The extremely-high pyrolysis temperatures afforded by the equilibrium plasma offer a unique particle growth environment, accommodating long deposition times while exposing resulting powders to temperatures in excess of 5000K without any additional particle nucleation and growth. Such conditions can yield short-range ordered amorphous BN structures in the form of 20nm diameter nanospheres. Finally, when introducing a rapid-quenching counter-flow gas against the plasma jet, high aspect ratio nanotubes are synthesized, which are collected on substrate situated radially. The benefits of these morphologies are also evident in high-pressure/high-temperature consolidation experiments, where nanoparticle phases can offer a favorable conversion route to super-hard c-BN while maintaining nanocrystallinity. Experiments using these morphologies are shown to begin to yield c-BN conversion at conditions as low as 2.0 GPa and 1500°C when using micron sized c-BN seeding to create localized regions of high pressures due to Hertzian forces acting on the nanoparticles.

  4. Industrial Scale Synthesis of Carbon Nanotubes Via Fluidized Bed Chemical Vapor Deposition: A Senior Design Project

    Science.gov (United States)

    Smith, York R.; Fuchs, Alan; Meyyappan, M.

    2010-01-01

    Senior year chemical engineering students designed a process to produce 10 000 tonnes per annum of single wall carbon nanotubes (SWNT) and also conducted bench-top experiments to synthesize SWNTs via fluidized bed chemical vapor deposition techniques. This was an excellent pedagogical experience because it related to the type of real world design…

  5. Synthesis and Characterization of Self-assembled polyaniline nanotubes/silica nanocomposites

    Czech Academy of Sciences Publication Activity Database

    Ciric-Marjanovic, G.; Dragičevic, L.; Milojevic, M.; Mojovic, M.; Mentus, S.; Dojčinovic, B.; Marjanovic, B.; Stejskal, Jaroslav

    2009-01-01

    Roč. 113, č. 20 (2009), s. 7116-7127 ISSN 1520-6106 R&D Projects: GA AV ČR IAA400500905 Institutional research plan: CEZ:AV0Z40500505 Keywords : polyaniline * conducting polymer * nanotubes Subject RIV: CD - Macromolecular Chemistry Impact factor: 3.471, year: 2009

  6. Synthesis of dark brown single-walled carbon nanotubes and their

    Indian Academy of Sciences (India)

    We report here a simple and effective approach to the covalent attachment of single-walled carbon nanotubes (SWCNTs) and azo compounds. The functionalized SWCNTs prepared (through a radical mechanism) have been used for a diazonium coupling reaction. The results showed that the chemical method used has ...

  7. Synthesis of dark brown single-walled carbon nanotubes and their ...

    Indian Academy of Sciences (India)

    Abstract. We report here a simple and effective approach to the covalent attachment of single-walled carbon nanotubes (SWCNTs) and azo compounds. The functionalized SWCNTs prepared (through a radical mecha- nism) have been used for a diazonium coupling reaction. The results showed that the chemical method ...

  8. Synthesis and characterization of titania nanotubes by anodizing of titanium in fluoride containing electrolytes

    Science.gov (United States)

    Ahmad, Akhlaq; Haq, Ehsan Ul; Akhtar, Waseem; Arshad, Muhammad; Ahmad, Zubair

    2017-11-01

    Titania nanotubular structure was prepared by anodizing titanium metal in the fluoride containing electrolytes and studied for hydrogen reduction using photo electrochemical cell. Potentiodynamic scan was performed before actual anodizing to optimize the anodizing conditions. The morphology of the TiO2 nanotubes was investigated by SEM and the presence of TiO2 nanotubes was confirmed. Raman spectroscopy was done to confirm the different phases present. Hydrogen generation capability was revealed by electrochemical testing in three-electrode system in dark and in visible light at 200 W power using Gamry Potentiostat. The corrosion potential of TiO2 nanotubes produced was found to be more active side in potassium hydroxide solution under visible light than in the dark condition. Cathodic polarization behavior of specimens in the presence of light showed more activity towards hydrogen generation than in dark condition. In comparison, the hydrogen generation capability of specimen anodized in 2H15 electrolyte was higher than specimens anodized in other electrolytes. Electrochemical impedance spectroscopy was used to study the charge transfer resistance of the nanotubes produced. The results showed that TiO2 nanotubular structure is a promising material for photoelectrochemical cell. Low-charge transfer resistance also depicts that it can be efficiently used to harvest solar energy.

  9. Self-combustion synthesis and oxygen storage properties of mesoporous gadolinia-doped ceria nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Yang Tao [College of Environmental and Energy Engineering, Beijing University of Technology (BUT-CEEE), Chaoyang District 100124, Beijing (China); Xia Dingguo, E-mail: yangtaophoenix@yahoo.com.cn [College of Environmental and Energy Engineering, Beijing University of Technology (BUT-CEEE), Chaoyang District 100124, Beijing (China)

    2010-10-01

    Ethyl glycol and citric acid, along with metal nitrates have been used to prepare Ce{sub 0.9}Gd{sub 0.1}O{sub 2-x} nanotubes directed at the anodic alumina oxide (AAO) template by combustion route. The tubes produced by the self-combustion route do not need any further calcination step. XRD patterns show the doped-ceria tubes have the flurite-type structure and no impurities are detected. The specific surface area of the tube is 112.7 m{sup 2} g{sup -1} and N{sub 2} adsorption-desorption profiles of the BET measurement shows the tubes are mesoporous. The largest aspect ratio of a nanotube reaches 20:1 and the TEM observation reveals the hollow structure. The Ce:Gd molar ratio calculated from the EDS and ICP-AES is 9:1 and the selected area electron diffraction confirms the flurite-type structure from the XRD characterization. The combined thermogravimetry-differential thermal analysis has been carried out to study the combustion reactions in the tube-forming process. The thermal stability of the nanotubes under both reductive and oxidative atmospheres is tested using the dynamic reduction/reoxidation reactions. At last, the oxygen storage capacity (OSC) of the nanotubes is calculated to be 695 {mu}mol-O{sup 2} g{sup -1} from the temperature-programed reduction reaction.

  10. Polypyrrole-coated halloysite nanotube clay nanocomposite: synthesis, characterization and Cr(VI) adsorption behaviour

    CSIR Research Space (South Africa)

    Ballav, N

    2014-12-01

    Full Text Available A polypyrrole-coated halloysite nanotube nanocomposite (PPy-HNTs NC) was prepared via in situ polymerization of pyrrole (Py) in the dispersion of HNTs and assessed for the removal of toxic Cr(VI) from aqueous solutions. ATR-FTIR and XRD results...

  11. Synthesis, characterization, and electrochemistry of nanotubular polypyrrole and polypyrrole-derived carbon nanotubes

    Czech Academy of Sciences Publication Activity Database

    Ciric-Marjanovic, G.; Mentus, S.; Pašti, I.; Gavrilov, N.; Krstic, J.; Travas-Sejdic, J.; Strover, L. T.; Kopecká, J.; Morávková, Zuzana; Trchová, Miroslava; Stejskal, Jaroslav

    2014-01-01

    Roč. 118, č. 27 (2014), s. 14770-14784 ISSN 1932-7447 R&D Projects: GA ČR GAP205/12/0911; GA ČR(CZ) GA13-00270S Institutional support: RVO:61389013 Keywords : polypyrrole * conductive polymer * nanotubes Subject RIV: CD - Macromolecular Chemistry Impact factor: 4.772, year: 2014

  12. Synthesis of photoactuating acrylic thermoplastic elastomers containing diblock copolymer-grafted carbon nanotubes

    Czech Academy of Sciences Publication Activity Database

    Ilčíková, M.; Mrlík, M.; Sedláček, T.; Šlouf, Miroslav; Zhigunov, Alexander; Koynov, K.; Mosnáček, J.

    2014-01-01

    Roč. 3, č. 10 (2014), s. 999-1003 ISSN 2161-1653 R&D Projects: GA TA ČR TE01020118 Institutional support: RVO:61389013 Keywords : photoactuating nanocomposite * carbon nanotubes * copolymer Subject RIV: CD - Macromolecular Chemistry Impact factor: 5.764, year: 2014

  13. Aqueous synthesis of porous platinum nanotubes at room temperature and their intrinsic peroxidase-like activity.

    Science.gov (United States)

    Cai, Kai; Lv, Zhicheng; Chen, Kun; Huang, Liang; Wang, Jing; Shao, Feng; Wang, Yanjun; Han, Heyou

    2013-07-11

    Platinum nanotubes (PtNTs) exhibiting high porosity were constructed by sacrificing the exterior of tellurium nanowires (TeNWs) and disintegrating the inner part spontaneously in aqueous solution at room temperature, in which the Kirkendall effect may play an important role. The present PtNTs exhibited intrinsic peroxidase-like activity in the presence of H2O2.

  14. Facile and large-scale synthesis and characterization of carbon nanotube/silver nanocrystal nanohybrids

    International Nuclear Information System (INIS)

    Gao Chao; Li Wenwen; Jin Yizheng; Kong Hao

    2006-01-01

    A facile and efficient aqueous phase-based strategy to synthesize carbon nanotube (CNT)/silver nanocrystal nanohybrids at room temperature is reported. In the presence of carboxyl group functionalized or poly(acrylic acid)- (PAA-) grafted CNTs, silver nanoparticles were in situ generated from AgNO 3 aqueous solution, without any additional reducing agent or irradiation treatment, and readily attached to the CNT convex surfaces, leading to the CNT/Ag nanohybrids. The produced silver nanoparticles were determined to be face-centred cubic silver nanocrystals by scanning transmission electron microscopy (STEM), electron diffraction (ED) and x-ray powder diffraction (XRD) analyses. Detailed experiments showed that this strategy can also be applied to different CNTs, including single-walled carbon nanotubes (SWNTs), double-walled carbon nanotubes (DWNTs), multiwalled carbon nanotubes (MWNTs), and polymer-functionalized CNTs. The nanoparticle sizes can be controlled from 2 nm to 10-20 nm and the amount of metal deposited on CNT surfaces can be as high as 82 wt%. Furthermore, large-scale (10 g or more) CNT/Ag nanohybrids can be prepared via this approach without the decrease of efficiency and quality. This approach can also be extended to prepare Au single crystals by CNTs. The facile, efficient and large-scale availability of the nanohybrids makes their tremendous potential realizable and developable

  15. Plasma synthesis of rare earth doped integrated optical waveguides

    Energy Technology Data Exchange (ETDEWEB)

    Raoux, S.; Anders, S.; Yu, K.M.; Brown, I.G. [Lawrence Berkeley Lab., CA (United States); Ivanov, I.C. [Charles Evans & Associates, Redwood City, CA (United States)

    1995-03-01

    We describe a novel means for the production of optically active planar waveguides. The makes use of a low energy plasma deposition. Cathodic-arc-produced metal plasmas the metallic components of the films and gases are added to form compound films. Here we discuss the synthesis of Al{sub 2{minus}x}ER{sub x}O{sub 3} thin films. The erbium concentration (x) can vary from 0 to 100% and the thickness of the film can be from Angstroms to microns. In such material, at high active center concentration (x=l% to 20%), erbium ions give rise to room temperature 1.53{mu}m emission which has minimum loss in silica-based optical fibers. With this technique, multilayer integrated planar waveguide structures can be grown, such as Al{sub 2}O{sub 3}/Al{sub 2{minus}x}Er{sub x}O{sub 3}/Al{sub 2}O{sub 3}/Si, for example.

  16. Optical properties of TiO2 nanotube arrays fabricated by the electrochemical anodization method

    International Nuclear Information System (INIS)

    Ly, Ngoc Tai; Nguyen, Van Chien; Dao, Thi Hoa; Hoang To, Le Hong; Pham, Duy Long; Do, Hung Manh; Vu, Dinh Lam; Le, Van Hong

    2014-01-01

    Perpendicularly self-aligned TiO 2 nanotube samples of size of 3 × 5 cm 2 were fabricated by the electrochemical anodization method using a solution containing NH 4 F. Influences of the technological conditions such as NH 4 F concentration and anodization voltage were studied. It was found that NH 4 F concentration in the solution and anodization voltage significantly affect the diameter and length of a TiO 2 nanotube. The diameter and the length of a TiO 2 nanotube were observed and estimated by using scanning electron microscopy. It has shown that the largest diameter and the longest length of about 80 nm and 20 μm, respectively, were obtained for the sample anodized in a solution containing 0.4% of NH 4 F, under a voltage of 48 V. Photoluminescence spectra excited by laser lights having wavelengths of 325 and 442 nm (having energies higher and lower than the band gap energy of TiO 2 ) was recorded at room temperature for the TiO 2 nanotube arrays. An abnormal luminescence result was observed. It is experimental evidence that the manufactured TiO 2 nanotube array is an expected material for hydrogen splitting from water by photochemical effect under sunlight as well as for the nano solar cells. (paper)

  17. Synthesis of carbon nanotubes by CVD method using iron and molybdenum-based catalysts supported on ceramic matrices

    International Nuclear Information System (INIS)

    Teixeira, Ana Paula de Carvalho

    2010-01-01

    Molybdenum is known for its synergistic effect in the synthesis of carbon nanotubes (CNs) by chemical vapor deposition (CVD method). When added to typical catalysts like iron, nickel, and cobalt, even in small quantities, it is increases the yield of these nanostructures. The presence of Mo also has an influence on the type and number of CN walls formed. Although this effect is widely documented in the literature, there is not yet a consensus about the mechanism of action of molybdenum in catalytic systems. The objective of the present work is to study the influence of molybdenum on the catalytic activity of iron nanoparticle-based catalysts supported on magnesium oxide (Fe/MgO system) in the synthesis of carbon nanotubes by the CVD method. The Mo concentration was systematically varied from null to molar ratio values four times greater than the quantity of Fe, and the obtained material (catalysts and carbon nanotubes) were broadly characterized by different techniques. In order to also study the influence of the preparation method on the final composition of the catalytic system phases, the catalytic systems (Fe/MgO e FeMo x /MgO) were synthesized by two different methods: co-precipitation and impregnation. The greatest CN yields were observed for the catalysts prepared by coprecipitation. The difference was attributed to better dispersion of the Fe and Mo phases in the catalyst ceramic matrix. In the precipitation stage, it was observed the formation of layered double hydroxides whose concentration increased with the Mo content up to the ratio of Mo/Fe equal to 0.2. This phase is related to a better distribution of Fe and Mo in this concentration range. Another important characteristic observed is that the ceramic matrix is not inert. It can react both with Fe and Mo and form the iron solid solution in the magnesium oxide and the phases magnesium-ferrite (MgFe 2 0 4 ) and magnesium molybdate (MgMo0 4 ). The MgFe 2 0 4 phase is observed in all catalytic systems

  18. Synthesis of calcium-phosphorous doped TiO2 nanotubes by anodization and reverse polarization: A promising strategy for an efficient biofunctional implant surface

    International Nuclear Information System (INIS)

    Alves, Sofia A.; Patel, Sweetu B.; Sukotjo, Cortino; Mathew, Mathew T.; Filho, Paulo N.; Celis, Jean-Pierre

    2017-01-01

    Highlights: • A new surface modification methodology for bio-functionalization of TiO2 NTs is addressed • Bone-like structured TiO2 nanotubular surfaces containing Ca and P were synthesized. • Ca/P-doped TiO2 NTs enhanced adhesion and proliferation of osteoblastic-like cells. • The bio-functionalization granted improved bio-electrochemical stability to TiO2 NTs. - Abstract: The modification of surface features such as nano-morphology/topography and chemistry have been employed in the attempt to design titanium oxide surfaces able to overcome the current dental implants failures. The main goal of this study is the synthesis of bone-like structured titanium dioxide (TiO 2 ) nanotubes enriched with Calcium (Ca) and Phosphorous (P) able to enhance osteoblastic cell functions and, simultaneously, display an improved corrosion behavior. To achieve the main goal, TiO 2 nanotubes were synthetized and doped with Ca and P by means of a novel methodology which relied, firstly, on the synthesis of TiO 2 nanotubes by anodization of titanium in an organic electrolyte followed by reverse polarization and/or anodization, in an aqueous electrolyte. Results show that hydrophilic bone-like structured TiO 2 nanotubes were successfully synthesized presenting a highly ordered nano-morphology characterized by non-uniform diameters. The chemical analysis of such nanotubes confirmed the presence of CaCO 3 , Ca 3 (PO 4 ) 2 , CaHPO 4 and CaO compounds. The nanotube surfaces submitted to reverse polarization, presented an improved cell adhesion and proliferation compared to smooth titanium. Furthermore, these surfaces displayed a significantly lower passive current in artificial saliva, and so, potential to minimize their bio-degradation through corrosion processes. This study addresses a very simple and promising multidisciplinary approach bringing new insights for the development of novel methodologies to improve the outcome of osseointegrated implants.

  19. A Comparative Study of the Effect of MgO and CaCO3 as Support Materials in the Synthesis of Carbon Nanotubes with Fe/Co as Catalyst

    Directory of Open Access Journals (Sweden)

    Ezekiel D. Dikio

    2014-01-01

    Full Text Available A comparative study of the effect of magnesium oxide and calcium carbonate as support material in the synthesis of carbon nanotubes using the catalyst Fe/Co is presented. The synthesized carbon nanotubes were characterized with Raman spectroscopy, scanning electron spectroscopy (SEM, high-resolution transmission electron microscopy (HRTEM, X-ray diffraction spectroscopy (XRD, and energy dispersive spectroscopy (EDS. The morphology of the carbon nanotubes synthesized with magnesium oxide as support material gives rise to carbon nanotubes with consistent and well-defined structure unlike that synthesized with calcium carbonate. The ID/IG ratio of synthesized carbon nanotubes (CNTs was 0.8544 for magnesium oxide supported compared to 0.8501 for calcium carbonate supported carbon nanotube.

  20. Nonlinear optical and optical limiting properties of fullerene, multi-walled carbon nanotubes, graphene and their derivatives with oxygen-containing functional groups

    International Nuclear Information System (INIS)

    Zhang, Xiao-Liang; Li, Xiao-Chun; Liu, Zhi-Bo; Yan, Xiao-Qing; Tian, Jian-Guo; Chen, Yong-Sheng

    2015-01-01

    Nonlinear optical properties (NLO) and optical limiting effect of fullerene (C 60 ), multi-walled carbon nanotubes (MWNTs), reduced graphene oxide (RGO) and their oxygenated derivatives were investigated by open-aperture Z-scan technique with nanosecond pulses at 532 nm. C 60 functionalized by oxygen-containing functional groups exhibits weaker NLO properties than that of pristine C 60 . Graphene oxide (GO) with many oxygen-containing functional groups also shows weaker NLO properties than that of RGO. That can be attributed to the disruption of conjugative structures of C 60 and graphene by oxygen-containing functional groups. However, MWNTs and their oxygenated derivatives exhibit comparable NLO properties due to the small weight ratio of these oxygen-containing groups. To investigate the correlation between structures and NLO response for these carbon nanomaterials with different dimensions, nonlinear scattered signal spectra versus input fluence were also measured. (paper)

  1. Optical excitation of carbon nanotubes drives stoichiometric reaction with diazonium salts

    Science.gov (United States)

    Powell, Lyndsey; Piao, Yanmei; Wang, Yuhuang; YuHuang Wang Research Group Team

    Covalent chemistry is known to lack the precision required to tailor the physical properties of carbon nanostructures. Here we show that, for the first time, light can be used to drive a typically inefficient reaction with single-walled carbon nanotubes in a more stoichiometric fashion. Specifically, our experimental results suggest that light can enhance the reaction rate of diazonium salt with carbon nanotubes by as much as 35-fold, making possible stoichiometric control of the covalent bonding of a functional group to the sp2 carbon lattice. This light-controlled reaction paves the way for the possibility of highly selective and precise chemistry on single-walled carbon nanotubes and other graphitic nanostructures.

  2. 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.

  3. Synthesis of Hollow Nanotubes of Zn2SiO4 or SiO2: Mechanistic Understanding and Uranium Adsorption Behavior.

    Science.gov (United States)

    Tripathi, Shalini; Bose, Roopa; Roy, Ahin; Nair, Sajitha; Ravishankar, N

    2015-12-09

    We report a facile synthesis of Zn2SiO4 nanotubes using a two-step process consisting of a wet-chemical synthesis of core-shell ZnO@SiO2 nanorods followed by thermal annealing. While annealing in air leads to the formation of hollow Zn2SiO4, annealing under reducing atmosphere leads to the formation of SiO2 nanotubes. We rationalize the formation of the silicate phase at temperatures much lower than the temperatures reported in the literature based on the porous nature of the silica shell on the ZnO nanorods. We present results from in situ transmission electron microscopy experiments to clearly show void nucleation at the interface between ZnO and the silica shell and the growth of the silicate phase by the Kirkendall effect. The porous nature of the silica shell is also responsible for the etching of the ZnO leading to the formation of silica nanotubes under reducing conditions. Both the hollow silica and silicate nanotubes exhibit good uranium sorption at different ranges of pH making them possible candidates for nuclear waste management.

  4. Synthesis of carbon nanotube using camphor with SS 316 as catalytic substrate via oxidative heat treatment preparation method

    Science.gov (United States)

    Wulan, Praswasti Pembangun Dyah Kencana; Angelina, Dian

    2017-11-01

    Carbon nanotube (CNT) is a material that now often become the topic in nanotechnology research. CNT is widely used in the electronics industry especially for TV and computer flat panel displays, devices, automotives for car components, and batteries. Also for defense industries as well as other industries such as sports equipment. Camphor (C10H16O), a botanical hydrocarbon, can be used as a renewable and low cost carbon source for CNT synthesis. Synthesis was performed with stainless steel-316 (SS 316) as substrate, argon as carrier gas, and hydrogen as co-reactant. Preparation of the SS 316 was through a pretreatment by oxidative heat treatment method at a temperature of 850oC for 30 minutes, to remove the layer of chrome and make a rough surface as a growth media for CNT. The operating temperature of the synthesis used was 800oC with a reaction time of 60 minutes. Reactor, which made from stainless steel 316 (SS 316), was used for synthesis CNTs with maximum camphor mass of 20 grams. This research was conducted by varying the number of camphor mass by 5, 7, 10, 12, and 15 grams. The results showed that camphor decomposed into three compounds which are 40% benzene, 8% toluene, and 52% xylene. CNT grows on the surface of the SS 316 plate for each variation. CNTs have grown by follow tips growth model with deformations like buckling growth model and continuous growth model were also founded. The results of XRD showed that CNT were found in every camphor mass variation with high intensity at 2θ angle of 26° and 43°. The best quality and yield of CNT was obtained at camphor mass of 15 grams with carbon percentage of 87,1% and diameter 33 - 44 nm.

  5. Synthesis and Characterization of RuO2/poly (3,4-ethylenedioxythiophene) (PEDOT) Composite Nanotubes for Supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Ran [Univ. of Maryland, College Park, MD (United States); Duay, Jonathon [Univ. of Maryland, College Park, MD (United States); Lane, Timothy [Univ. of Maryland, College Park, MD (United States); Lee, Sang Bok [Univ. of Maryland, College Park, MD (United States); Korea Advance Inst. of Science and Technology, Daejeon (Korea)

    2010-01-18

    We report the synthesis of composite RuO2/poly(3,4-ethylenedioxythiophene) (PEDOT) nanotubes with high specific capacitance and fast charging/discharging capability as well as their potential application as electrode materials for a high-energy and high-power supercapacitor. RuO2/PEDOT nanotubes were synthesized in a porous alumina membrane by a step-wise electrochemical deposition method, and their structures were characterized using electron microscopy. Cyclic voltammetry was used to qualitatively characterize the capacitive properties of the composite RuO2/PEDOT nanotubes. Their specific capacitance, energy density and power density were evaluated by galvanostatic charge/discharge cycles at various current densities. The pseudocapacitance behavior of these composite nanotubes originates from ion diffusion during the simultaneous and parallel redox processes of RuO2 and PEDOT. We show that the energy density (specific capacitance) of PEDOT nanotubes can be remarkably enhanced by electrodepositing RuO2 into their porous walls and onto their rough internal surfaces. The flexible PEDOT prevents the RuO2 from breaking and detaching from the current collector while the rigid RuO2 keeps the PEDOT nanotubes from collapsing and aggregating. The composite RuO2/PEDOT nanotube can reach a high power density of 20 kW kg-1 while maintaining 80% energy density (28 Wh kg-1) of its maximum value. This high power capability is attributed to the fast charge/discharge of nanotubular structures: hollow nanotubes allow counter-ions to readily penetrate into the composite material and access their internal surfaces, while a thin wall provides a short diffusion distance to facilitate ion transport. The high energy density originates from the RuO2, which can store high electrical/electrochemical energy intrinsically. The high specific capacitance (1217 Fg-1

  6. EDITORIAL: Focus on Carbon Nanotubes

    Science.gov (United States)

    2003-09-01

    The study of carbon nanotubes, since their discovery by Iijima in 1991, has become a full research field with significant contributions from all areas of research in solid-state and molecular physics and also from chemistry. This Focus Issue in New Journal of Physics reflects this active research, and presents articles detailing significant advances in the production of carbon nanotubes, the study of their mechanical and vibrational properties, electronic properties and optical transitions, and electrical and transport properties. Fundamental research, both theoretical and experimental, represents part of this progress. The potential applications of nanotubes will rely on the progress made in understanding their fundamental physics and chemistry, as presented here. We believe this Focus Issue will be an excellent guide for both beginners and experts in the research field of carbon nanotubes. It has been a great pleasure to edit the many excellent contributions from Europe, Japan, and the US, as well from a number of other countries, and to witness the remarkable effort put into the manuscripts by the contributors. We thank all the authors and referees involved in the process. In particular, we would like to express our gratitude to Alexander Bradshaw, who invited us put together this Focus Issue, and to Tim Smith and the New Journal of Physics staff for their extremely efficient handling of the manuscripts. Focus on Carbon Nanotubes Contents Transport theory of carbon nanotube Y junctions R Egger, B Trauzettel, S Chen and F Siano The tubular conical helix of graphitic boron nitride F F Xu, Y Bando and D Golberg Formation pathways for single-wall carbon nanotube multiterminal junctions Inna Ponomareva, Leonid A Chernozatonskii, Antonis N Andriotis and Madhu Menon Synthesis and manipulation of carbon nanotubes J W Seo, E Couteau, P Umek, K Hernadi, P Marcoux, B Lukic, Cs Mikó, M Milas, R Gaál and L Forró Transitional behaviour in the transformation from active end

  7. Facile Synthesis of Polyaniline Nanotubes with Square Capillary Using Urea as Template

    Directory of Open Access Journals (Sweden)

    Shuhua Pang

    2017-10-01

    Full Text Available Polyaniline nanotubes were successfully synthesized by a facile in situ chemical oxidative polymerization method using urea as soft template. When the urea/aniline molar ratio is 3:1, the as-prepared nanotubular polyaniline (PANI-3 shows regular and uniform square capillaries, which provides a high electrode/electrolyte contact, easy ion diffusion and enhanced electroactive regions during the electrochemical process, leading to weak internal resistance and improved electrochemical performance. The PANI-3 sample exhibits a high specific capacitance of 405 F/g at current density of 0.2 A/g, and PANI only has a specific capacitance of 263 F/g. At current density of 1 A/g, the capacitance of PANI-3 is still 263 F/g (64.9% of the capacitance at 0.2 A/g. Such a PANI-3 nanotube, with regular and uniform capillary, is a promising electrode material for high-performance supercapacitors.

  8. CVD-grown horizontally aligned single-walled carbon nanotubes: synthesis routes and growth mechanisms.

    Science.gov (United States)

    Ibrahim, Imad; Bachmatiuk, Alicja; Warner, Jamie H; Büchner, Bernd; Cuniberti, Gianaurelio; Rümmeli, Mark H

    2012-07-09

    Single-walled carbon nanotubes (SWCNTs) have attractive electrical and physical properties, which make them very promising for use in various applications. For some applications however, in particular those involving electronics, SWCNTs need to be synthesized with a high degree of control with respect to yield, length, alignment, diameter, and chirality. With this in mind, a great deal of effort is being directed to the precision control of vertically and horizontally aligned nanotubes. In this review the focus is on the latter, horizontally aligned tubes grown by chemical vapor deposition (CVD). The reader is provided with an in-depth review of the established vapor deposition orientation techniques. Detailed discussions on the characterization routes, growth parameters, and growth mechanisms are also provided. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Optimal Synthesis of Horizontally Aligned Single-Walled Carbon Nanotubes and Their Biofunctionalization for Biosensing Applications

    Directory of Open Access Journals (Sweden)

    Dawoon Jung

    2016-01-01

    Full Text Available As an influential candidate for highly sensitive biomolecule sensor, which can capture disease related biomolecules, carbon nanotube is useful material due to its unique properties. To adopt as a sensing platform, it is strongly needed to find optimal refined synthetic condition. In order to find the optimal synthetic conditions of horizontally aligned CNT, we performed quantity control of the mixed gases of H2 and CH4 injected. We successfully find that the formation of amorphous-like carbon was critically affected by some gas condition such as the flow rate of injected gases and ratios of gas mixture. Moreover, it should be noted that our horizontally aligned carbon nanotube array platform developed would offer another potential in developing nanoscale light source, where light emission results from electron-hole carrier recombination.

  10. Synthesis of Au nanotubes with SiOx nanowires as sacrificial templates

    International Nuclear Information System (INIS)

    Lu, M.Y.; Chang, Y.C.; Chen, L.J.

    2006-01-01

    Gold nanotubes with SiO x nanowires as sacrificial templates have been synthesized. SiO x nanowires were functionalized by 3-aminopropyl trimethoxysilane that generates a charged surface. The attachment of negatively charged Au nanoparticles was followed. The coverage of Au nanoparticles was initially less than 30%. Further coverage was achieved by the reduction of gold hydroxide to grow the continuous nanoshell on Au nanoparticles, which serve as nucleation sites. The final coverage of Au nanoshells on SiO x nanowires depends strongly on the relative amount of SiO x nanowires in gold hydroxide solution. Both transmission electron microscope and scanning electron microscope images revealed the formation of Au nanotubes with the removal of SiO x nanowires by etching in a dilute HF solution

  11. Synthesis of boron nitride nanotubes with SiC nanowire as template

    International Nuclear Information System (INIS)

    Zhong, B.; Song, L.; Huang, X.X.; Wen, G.W.; Xia, L.

    2011-01-01

    Highlights: → Boron nitride nanotubes (BNNTs) have been fabricated using SiC nanowires as template. → SiC nanowires could be effectively etched out by the vapors decomposed from ammonia borane, leading to the formation of BNNTs. → A template self-sacrificing mechanism is responsible for the formation of BNNTs. -- Abstract: A novel template method for the preparation of boron nitride nanotubes (BNNTs) using SiC nanowire as template and ammonia borane as precursor is reported. We find out that the SiC nanowires could be effectively etched out by the vapors decomposed from ammonia borane, leading to the formation of BNNTs. The as-prepared products are well characterized by means of complementary analytical techniques. A possible formation mechanism is disclosed. The method developed here paves the way for large scale production of BNNTs.

  12. Water-dispersed thermo-responsive boron nitride nanotubes: synthesis and properties

    Czech Academy of Sciences Publication Activity Database

    Kalay, S.; Stetsyshyn, Y.; Lobaz, Volodymyr; Harhay, K.; Ohar, H.; Ҫulha, M.

    2016-01-01

    Roč. 27, č. 3 (2016), 035703_1-035703_8 ISSN 0957-4484 R&D Projects: GA ČR(CZ) GA13-08336S; GA MPO(CZ) FR-TI4/625 Institutional support: RVO:61389013 Keywords : boron nitride nanotubes * thermo-responsive polymer brushes * poly(N-isopropylacrylamide) Subject RIV: CA - Inorganic Chemistry Impact factor: 3.440, year: 2016

  13. Synthesis and investigation of PMMA films with homogeneously dispersed multiwalled carbon nanotubes

    International Nuclear Information System (INIS)

    Pantoja-Castro, M.A.; Pérez-Robles, J.F.; González-Rodríguez, H.; Vorobiev-Vasilievitch, Y.; Martínez-Tejada, H.V.; Velasco-Santos, C.

    2013-01-01

    Multiwalled carbon nanotubes (MWNT) modified by 2.2′-azoiso-butyronitrile (AIBN) were incorporated into methyl methacrylate (MMA) by sonochemistry method, resulting in homogenous dispersion of MWNT, which makes possible to obtain flexible conductive polymer-matrix nanocomposites films of PMMA, with MWNT concentrations ranging from 0 to 0.5 wt%. Modified MWNT (AIBN-MWNT) were studied by Fourier transform infrared (FT-IR), Raman spectroscopy, X-ray Photoelectron Spectroscopy (XPS) and through visual observations in order to compare the dispersion in 2-propanone and toluene with that of pristine MWNT. Synthesized PMMA-AIBN-MWNT films were studied by FT-IR and Raman spectroscopy. Using FT-IR for the AIBN-MWNT it was not possible to identify any group or groups attached to the nanotubes. Raman spectroscopy shows a small modification in the Lorentzian peaks ratio I D/G of AIBN-MWNT, meanwhile XPS showed that atomic compositions does not change for AIBN-MWNT compared to the pristine nanotubes. Also by impedance it was analyzed the conductivity of PMMA-MWNT films and the results showed a threshold percolation at 0.5 wt%. FT-IR and Raman analyses for PMMA-AIBN-MWNT composite indicate a covalent bonding between PMMA and MWNT due to the opening of π-bonds of the nanotubes, which is related with a possible proposed reaction scheme. - Graphical abstract: Display Omitted - Highlights: • We used sonochemistry-in situ polymerization to disperse MWNT very soon in PMMA. • A high and homogenous dispersion of MWNT in PMMA was achieved. • The modification of MWNT by AIBN was analyzed using Raman. • A covalent bonding between PMMA and MWNT was analyzed by FT-IR and Raman. • According to the results of PMMA-MWNT it was proposed a scheme reaction

  14. Synthesis of PMMA-co-PMAA copolymer brush on multi-wall carbon nanotubes

    Czech Academy of Sciences Publication Activity Database

    Slobodian, P.; Svoboda, P.; Říha, Pavel; Bořuta, R.; Sáha, P.

    2012-01-01

    Roč. 2, č. 3 (2012), s. 221-226 ISSN 2161-4881 Grant - others:OP VaVpI(XE) CZ.1.05/2.1.00/03.0111; UTB Zlín(CZ) IGA/FT/2012/ 022 Institutional research plan: CEZ:AV0Z20600510 Keywords : carbon nanotubes * functionalization * PMMA * PMAA * polymer brush Subject RIV: JI - Composite Materials

  15. Encapsulating Reactive Nanoparticles in Carbon Nanotubes Using Flame-Based Synthesis

    Science.gov (United States)

    2008-12-22

    Nanoparticles, Nanotubes, and Nanowires,” Corning /Rutgers Research Symposium, Corning , NY, Feb 25, 2008. Zak, A., D’Esposito, C., and Tse, S.D., Premixed...configuration, there is excellent control of pyrolysis effects. By mounting a substrate probe to a linear translation stage, CNT growth and...are largely comprised of pyrolysis vapors that have not passed through the oxidation zone. As such, soot formation processes, which compete with CNT

  16. Synthesis and investigation of PMMA films with homogeneously dispersed multiwalled carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Pantoja-Castro, M.A., E-mail: m_pantojaq@yahoo.com.mx [Facultad de Ingeniería Química, Universidad Michoacana de San Nicolás de Hidalgo, Av. J. Múgica S/N Col., Villa Universidad, CP 58040 Morelia, Michoacán (Mexico); Pérez-Robles, J.F. [Centro de Investigación y de Estudios Avanzados del IPN, Unidad Querétaro, Libramiento Norponiente #2000, Fracc. Real de Juriquilla, CP 76230 Querétaro (Mexico); González-Rodríguez, H. [Facultad de Ingeniería Química, Universidad Michoacana de San Nicolás de Hidalgo, Av. J. Múgica S/N Col., Villa Universidad, CP 58040 Morelia, Michoacán (Mexico); Vorobiev-Vasilievitch, Y. [Centro de Investigación y de Estudios Avanzados del IPN, Unidad Querétaro, Libramiento Norponiente #2000, Fracc. Real de Juriquilla, CP 76230 Querétaro (Mexico); Martínez-Tejada, H.V. [Instituto de Energía, Materiales y Medio Ambiente, Universidad Pontificia Bolivariana, Circular 1 No. 70-01, Bloque 22, Medellín (Colombia); Velasco-Santos, C. [Centro de Física Aplicada y Tecnología Avanzada, Universidad Autónoma de México, Av. Boulevard Juriquilla, No. 3001 Juriquilla, CP 76230 Querétaro (Mexico)

    2013-07-15

    Multiwalled carbon nanotubes (MWNT) modified by 2.2′-azoiso-butyronitrile (AIBN) were incorporated into methyl methacrylate (MMA) by sonochemistry method, resulting in homogenous dispersion of MWNT, which makes possible to obtain flexible conductive polymer-matrix nanocomposites films of PMMA, with MWNT concentrations ranging from 0 to 0.5 wt%. Modified MWNT (AIBN-MWNT) were studied by Fourier transform infrared (FT-IR), Raman spectroscopy, X-ray Photoelectron Spectroscopy (XPS) and through visual observations in order to compare the dispersion in 2-propanone and toluene with that of pristine MWNT. Synthesized PMMA-AIBN-MWNT films were studied by FT-IR and Raman spectroscopy. Using FT-IR for the AIBN-MWNT it was not possible to identify any group or groups attached to the nanotubes. Raman spectroscopy shows a small modification in the Lorentzian peaks ratio I{sub D/G} of AIBN-MWNT, meanwhile XPS showed that atomic compositions does not change for AIBN-MWNT compared to the pristine nanotubes. Also by impedance it was analyzed the conductivity of PMMA-MWNT films and the results showed a threshold percolation at 0.5 wt%. FT-IR and Raman analyses for PMMA-AIBN-MWNT composite indicate a covalent bonding between PMMA and MWNT due to the opening of π-bonds of the nanotubes, which is related with a possible proposed reaction scheme. - Graphical abstract: Display Omitted - Highlights: • We used sonochemistry-in situ polymerization to disperse MWNT very soon in PMMA. • A high and homogenous dispersion of MWNT in PMMA was achieved. • The modification of MWNT by AIBN was analyzed using Raman. • A covalent bonding between PMMA and MWNT was analyzed by FT-IR and Raman. • According to the results of PMMA-MWNT it was proposed a scheme reaction.

  17. Ferromagnetic resonance of cobalt nanoparticles used as a catalyst for the carbon nanotubes synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Duraia, El-Shazly M. [Suez Canal University, Faculty of Science, Physics Department, Ismailia (Egypt); Al-Farabi Kazakh National University, Almaty (Kazakhstan); Institute of Physics and Technology, Almaty (Kazakhstan)], E-mail: duraia_physics@yahoo.com; Abdullin, Kh.A. [Institute of Physics and Technology, Almaty (Kazakhstan)

    2009-12-15

    Catalyst is considered to be the most crucial parameter for the growth of carbon nanotubes. In this work we study the ferromagnetic resonance (FMR) spectra of the catalyst nanoclusters. Moreover we report for the first time the angle FMR studies of catalyst particles with and without CNT layer. The dependencies of the FMR spectra, X-ray diffraction (XRD) patterns, Raman spectra and morphology of the CNT layers on the growth conditions are discussed.

  18. Corrigendum to "Synthesis of hydroxyapatite/multi-walled carbon nanotubes for the removal of fluoride ions from solution" [Appl. Surf. Sci. 412 (2017) 578-590

    Science.gov (United States)

    Ruan, Zhongyuan; Tian, Yaxi; Ruan, Jifu; Cui, Guijia; Iqbal, Kanwal; Iqbal, Anam; Ye, Herui; Yang, Zhangzhong; Yan, Shiqiang

    2018-04-01

    In our recent paper [1], we reported the synthesis of hydroxyapatite/multi-walled carbon nanotubes (HA-MWCNTs) and studied their performance for the removal of fluoride ions from solution. However, we have made some writing mistakes, especially in the section on adsorption kinetics analysis. Our mistakes were spotted by Prof. Yuandong Huang, who graciously noticed these errors. We are grateful to him, and have decided to write a "Corrigendum".

  19. Sol-gel auto-combustion synthesis of hydroxyapatite nanotubes array in porous alumina template

    International Nuclear Information System (INIS)

    Yuan Yuan; Liu Changsheng; Zhang Yuan; Shan Xiaoqian

    2008-01-01

    In this paper, an array of highly ordered hydroxyapatite (HAP) nanotubes was synthesized by sol-gel auto-combustion method with porous anodic aluminum oxide (AAO) template for the first time. Based on thermogravimetry (DTA/TG), Fourier transform infrared (FTIR) and X-ray diffraction (XRD), the dried gel, derived from the sol solution with Ca(NO 3 ) 2 .4H 2 O and PO(CH 3 O) 3 as precursors and ethylene glycol as the polymeric matrix, exhibited a typical self-propagating combustion behavior at low temperature, directly resulting in hexagonal crystalline HAP materials. The resultant HAP arrays fabricated from the above sol-gel in the AAO template were uniformly distributed, highly ordered nanotubes with uniform length and diameter according to the observations of scanning electron microscopy (SEM) and transmission electron microscope (TEM). The electron diffraction (ED), XRD and X-ray photoelectron spectroscopy (XPS) survey proved the formation of HAP phase with polycrystalline structure in the AAO template. Based on these results, a potential mechanism of 'an auto-combustion from dried gel to nanoparticles and a subsequent in situ reaction from nanoparticles to nanotubes' was proposed

  20. Synthesis of carbon nanotubes from palm oil on stacking and non-stacking substrate by thermal-CVD method

    Science.gov (United States)

    Robaiah, M.; Rusop, M.; Abdullah, S.; Khusaimi, Z.; Azhan, H.; Fadzlinatul, M. Y.; Salifairus, M. J.; Asli, N. A.

    2018-05-01

    Palm oil has been used as the carbon source to synthesize carbon nanotubes (CNTs) on silicon substrates using the thermal chemical vapor deposition (CVD) method. Meanwhile, silicon has been applied using two techniques, which are stacked technique and non-stacked technique. The CNTs were grown at the constant time of 30 minutes with various synthesis temperatures of 750 °C, 850 °C and 950 °C. The CNTs were characterized using micro-Raman spectroscopy and field emission scanning electron microscopy (FESEM). It was found that the density, growth rate, diameter and length of the CNTs produced were affected by the synthesis temperature. Moreover, the structure slightly changes were observed between CNTs obtained in SS and NSS. The synthesize temperature of 750 °C was considered as the suitable temperature for the production of CNTs due to low ID/IG ratio, which for stacked is 0.89 and non-stacked are 0.90. The possible explanation for the different morphology of the produced CNTs was also discussed.

  1. Study of optical properties of vacuum evaporated carbon nanotube containing Se80Te16Cu4 thin films

    Science.gov (United States)

    Upadhyay, A. N.; Tiwari, R. S.; Singh, Kedar

    2016-08-01

    Thin films of Se80Te16Cu4 glassy alloy and 3 wt.% of carbon nanotubes (CNTs) containing Se80Te16Cu4 glassy composite were deposited on clean glass substrate by thermal evaporation technique. The scanning electron microscope and energy dispersive x-ray analysis were performed to investigate the surface morphology and elemental composition of as synthesised samples. The reflectance and transmittance spectra of as-deposited thin films were recorded (200-1100 nm) by using UV/VIS/NIR spectrophotometer. The optical band gap and optical constants such as absorption coefficient (α), refractive index (n) and extinction coefficient (k) of Se80Te16Cu4 and 3 wt.% CNTs-Se80Te16Cu4 glassy composite thin films were calculated. It is observed that optical properties alter due to CNTs incorporation in Se80Te16Cu4 glassy alloy. Effect on optical properties due to CNTs incorporation can be explained in terms of concentration of unsaturated bonds/defects in the localised states.

  2. Optical trapping of cold neutral atoms using a two-color evanescent light field around a carbon nanotube

    International Nuclear Information System (INIS)

    Nga, Do Thi; Viet, Nguyen Ai; Nga, Dao Thi Thuy; Lan, Nguyen Thi Phuong

    2014-01-01

    We suggest a new schema of trapping cold atoms using a two-color evanescent light field around a carbon nanotube. The two light fields circularly polarized sending through a carbon nanotube generates an evanescent wave around this nanotube. By evanescent effect, the wave decays away from the nanotube producing a set of trapping minima of the total potential in the transverse plane as a ring around the nanotube. This schema allows capture of atoms to a cylindrical shell around the nanotube. We consider some possible boundary conditions leading to the non-trivial bound state solution. Our result will be compared to some recent trapping models and our previous trapping models.

  3. Synthesis and characterizations of Cu2ZnSnS4 nanoparticles/carbon nanotube composite as an efficient absorber material for solar cell application

    Science.gov (United States)

    Das, S.; Sa, K.; Alam, I.; Mahakul, P. C.; Raiguru, J.; Subramanyam, B. V. R. S.; Mahanandia, P.

    2018-05-01

    In this energy crisis era, the urgent calls for clean energy converter realizes the importance of photovoltaic device, which offers the highest probability of delivering a sustainable way of harvesting solar energy. The active absorber layer has its significance towards the performance of photovoltaic device by absorbing solar light and creating electron-hole pair inside layer. Being a direct p-type semiconductor, Cu2ZnSnS4 generally referred as CZTS has emerged as potential absorber towards photovoltaics application in recent decades as it offers the advantage of tunable band gap near optimal region ˜1.45-1.65 eV favorably match the solar spectrum and a high absorption coefficient ˜104 cm-1. The further improvement in the performance of CZTS based photovoltaics has involved the use of carbon nanotubes (CNTs). Semiconductors hybridized with carbonaceous materials (CNTs) have been the center of attraction in the scientific community with beneficial contribution in enhancing optoelectronic properties. The incorporation of CNTs shows effectiveness in charge carrier transfer pathways which ultimately could enhance the photo conversion efficiency (PCE) of photovoltaic device cell (PVC). Here, a facile hydrothermal one-pot synthesis of CZTS nanoparticles and MWCNTs composite towards photovoltaics application is reported. The phase and structural analysis of CZTS nanoparticles as well as CZTS/MWCNTs composite is done by XRD. From FERSEM and TEM (LRTEM & HRTEM) analysis the CZTS nanoparticles decorated over the surface of MWCNTs is confirmed. The optical band gap of CZTS/MWCNTs composite is estimated to be 1.62 eV from UV-Visible spectra.

  4. Optical absorption of carbon nanotube diodes: Strength of the electronic transitions and sensitivity to the electric field polarization

    Science.gov (United States)

    Mencarelli, Davide; Pierantoni, Luca; Rozzi, Tullio

    2008-03-01

    Aim of this work is to model electrostatically doped carbon nanotubes (CNT), which have recently proved to perform as ideal PN diodes, also showing photovoltaic properties. The new model is able to predict the optical absorption of semiconducting CNT as function of size and chirality. We justify theoretically, for the first time, the experimentally observed capability of CNTs to detect and select not only a well defined set of frequencies, as resulting from their discrete band structure, but also the polarization of the incident radiation. The analysis develops from an approach proposed in a recent contribution. The periodic structure of CNTs is formally modeled as a photonic crystal, that is characterized by means of numerical simulators. Longitudinal and transverse components of the electric field are shown to excite distinct interband transitions between well defined energy levels. Equivalently, for a given energy of the incident radiation, absorption may show polarization ratios strongly exceeding unity.

  5. A Facile Synthesis of a Palladium-Doped Polyaniline-Modified Carbon Nanotube Composites for Supercapacitors

    Science.gov (United States)

    Giri, Soumen; Ghosh, Debasis; Malas, Asish; Das, Chapal Kumar

    2013-08-01

    Supercapacitors have evolved as the premier choice of the era for storing huge amounts of charge in the field of energy storage devices, but it is still necessary to enhance their performance to meet the increasing requirements of future systems. This could be achieved either through advancing the interfaces of the material at the nanoscale or by using novel material compositions. We report a high-performance material composition prepared by combining a transition metal (palladium)-doped conductive polymer with multiwalled carbon nanotubes (MWCNTs). MWCNTs/palladium-doped polyaniline (MWCNTs/Pd/PANI) composites and multiwalled carbon nanotube/polyaniline (MWCNTs/PANI) composites (for comparison) were prepared via in situ oxidative polymerization of aniline monomer. The reported composites were characterized by Fourier-transform infrared (FTIR), x-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM) studies. FESEM and TEM studies indicated the narrow size distribution of the π-conjugated polymer-protected palladium nanoparticles on the surface of the carbon nanotubes. All the electrochemical characterizations were executed using a three-electrode system in 1 M H2SO4 electrolyte. Cyclic voltammetry (CV) analysis was performed to observe the capacitive performance and redox behavior of the composites. The ion transfer behavior and cyclic stability of the composites were investigated by electrochemical impedance spectroscopy (EIS) analysis and cyclic charge-discharge (CCD) testing, respectively. The MWCNTs/Pd/PANI composite was found to exhibit an especially high specific capacitance value of 920 F/g at scan rate of 2 mV/s.

  6. The synthesis and application involving regulation of the insoluble drug release from mesoporous silica nanotubes

    International Nuclear Information System (INIS)

    Li, Jia; Wang, Yan; Zheng, Xin; Zhang, Ying; Sun, Changshan; Gao, Yikun; Jiang, Tongying; Wang, Siling

    2015-01-01

    Highlights: • Mesoporous silica nanotubes (SNT) were synthesized by using CNT as hard template, and the formation of the SNT shows that CTAB played a significant effect on the coating process. • The tube mesoporous silica materials which were seldom reported were applied in the drug delivery system to improve the loading amount and the drug dissolution. • The release rate could be controlled by the gelatin layer on the silica surface and the mechanism was illustrated. - Abstract: Mesoporous silica nanotubes (SNT) were synthesized using hard template carbon nanotubes (CNT) with the aid of cetyltrimethyl ammonium bromide (CTAB) in a method, which was simple and inexpensive. Scanning electron microscopy, transmission electron microscopy and specific surface area analysis were employed to characterize the morphology and structure of SNT, and the formation mechanism of SNT was also examined by Fourier transform infrared spectroscopy. There are few published reports of the mesoporous SNT with large specific surface area applied in the drug delivery systems to improve the amount of drug loading. In addition, the structure of SNT allows investigators to control the drug particle size in the pore channels and significantly increase the drug dissolution rate. The insoluble drug, cilostazol, was chosen as a model drug to be loaded into SNT and we developed a simple and efficient method for regulating the drug release by using a gelatin coating with different thicknesses around the SNT. The release rate was adjusted by the amount of gelatin surrounding the SNT, with an increased barrier leading to a reduction in the release rate. A model developed on the basis of the Weibull modulus was established to fit the release results

  7. Optical properties of graphene nanoribbons encapsulated in single-walled carbon nanotubes.

    Science.gov (United States)

    Chernov, Alexander I; Fedotov, Pavel V; Talyzin, Alexandr V; Suarez Lopez, Inma; Anoshkin, Ilya V; Nasibulin, Albert G; Kauppinen, Esko I; Obraztsova, Elena D

    2013-07-23

    We report the photoluminescence (PL) from graphene nanoribbons (GNRs) encapsulated in single-walled carbon nanotubes (SWCNTs). New PL spectral features originating from GNRs have been detected in the visible spectral range. PL peaks from GNRs have resonant character, and their positions depend on the ribbon geometrical structure in accordance with the theoretical predictions. GNRs were synthesized using confined polymerization and fusion of coronene molecules. GNR@SWCNTs material demonstrates a bright photoluminescence both in infrared (IR) and visible regions. The photoluminescence excitation mapping in the near-IR spectral range has revealed the geometry-dependent shifts of the SWCNT peaks (up to 11 meV in excitation and emission) after the process of polymerization of coronene molecules inside the nanotubes. This behavior has been attributed to the strain of SWCNTs induced by insertion of the coronene molecules.

  8. 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.

  9. Surprising synthesis of nanodiamond from single-walled carbon nanotubes by the spark plasma sintering process

    Science.gov (United States)

    Mirzaei, Ali; Ham, Heon; Na, Han Gil; Kwon, Yong Jung; Kang, Sung Yong; Choi, Myung Sik; Bang, Jae Hoon; Park, No-Hyung; Kang, Inpil; Kim, Hyoun Woo

    2016-10-01

    Nanodiamond (ND) was successfully synthesized using single-walled carbon nanotubes (SWCNTs) as a pure solid carbon source by means of a spark plasma sintering process. Raman spectra and X-ray diffraction patterns revealed the generation of the cubic diamond phase by means of the SPS process. Lattice-resolved TEM images confirmed that diamond nanoparticles with a diameter of about ˜10 nm existed in the products. The NDs were generated mainly through the gas-phase nucleation of carbon atoms evaporated from the SWCNTs. [Figure not available: see fulltext.

  10. 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.

  11. Electronic structures and optical properties of GaN nanotubes with MgGa–ON co-doping

    International Nuclear Information System (INIS)

    Yang, Mao; Shi, Jun-jie; Zhang, Min; Zhang, Shuai; Bao, Zhi-qiang; Luo, Shao-jun; Zhou, Tie-Cheng; Zhu, Tian-cong; Li, Xiang; Li, Jia

    2013-01-01

    Both the electronic structures and the optical properties of single-walled zigzag GaN nanotubes (NTs) with Mg Ga –O N co-doping are investigated using first-principles calculations. We find that the Mg Ga –O N defect complex can exist stably in GaN NTs. The direct band gap width of the GaN NTs can be reduced by means of the Mg Ga –O N co-doping. The electrons of the valence band maximum (VBM) state are localized around the N atoms bonded with the Mg atom. The imaginary part ε 2 of the complex dielectric function of GaN NTs with Mg Ga –O N co-doping has a sharp peak closely related to the optical transitions between the VBM and conduction band minimum states. - Highlights: ► The Mg Ga –O N defect complex can exist stably in GaN NTs. ► The band gap of the GaN NTs can be reduced due to the Mg Ga –O N co-doping. ► The VBM states are localized around the N atoms bonded with the Mg atom. ► The ε 2 -plot has a peak related to the optical transition from the VBM to CBM state

  12. Photothermal optical coherence tomography for depth-resolved imaging of mesenchymal stem cells via single wall carbon nanotubes

    Science.gov (United States)

    Subhash, Hrebesh M.; Connolly, Emma; Murphy, Mary; Barron, Valerie; Leahy, Martin

    2014-03-01

    The progress in stem cell research over the past decade holds promise and potential to address many unmet clinical therapeutic needs. Tracking stem cell with modern imaging modalities are critically needed for optimizing stem cell therapy, which offers insight into various underlying biological processes such as cell migration, engraftment, homing, differentiation, and functions etc. In this study we report the feasibility of photothermal optical coherence tomography (PT-OCT) to image human mesenchymal stem cells (hMSCs) labeled with single-walled carbon nanotubes (SWNTs) for in vitro cell tracking in three dimensional scaffolds. PT-OCT is a functional extension of conventional OCT with extended capability of localized detection of absorbing targets from scattering background to provide depth-resolved molecular contrast imaging. A 91 kHz line rate, spectral domain PT-OCT system at 1310nm was developed to detect the photothermal signal generated by 800nm excitation laser. In general, MSCs do not have obvious optical absorption properties and cannot be directly visualized using PT-OCT imaging. However, the optical absorption properties of hMSCs can me modified by labeling with SWNTs. Using this approach, MSC were labeled with SWNT and the cell distribution imaged in a 3D polymer scaffold using PT-OCT.

  13. 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.

  14. Synthesis of Co-Electrospun Lead Selenide Nanostructures within Anatase Titania Nanotubes for Advanced Photovoltaics

    Directory of Open Access Journals (Sweden)

    Evan K. Wujcik

    2015-06-01

    Full Text Available Inorganic nano-scale heterostructures have many advantages over hybrid organic-inorganic dye-sensitized solar cells (DSSC or Grätzel cells, including their resistance to photo-bleaching, thermal stability, large specific surface areas, and general robustness. This study presents a first-of-its-kind low-cost all-inorganic lead selenide-anatase titania (PbSe/TiO2 nanotube heterostructure material for photovoltaic applications. Herein, PbSe nanostructures have been co-electrospun within a hollow TiO2 nanotube with high connectivity for highly efficient charge carrier flow and electron-hole pair separation. This material has been characterized by transmission electron microscopy (TEM, electron diffraction, energy dispersive X-ray spectroscopy (EDX to show the morphology and material composition of the synthesized nanocomposite. Photovoltaic characterization has shown this newly synthesized proof-of-concept material can easily produce a photocurrent under solar illumination, and, with further refinement, could reveal a new direction in photovoltaic materials.

  15. Hydrothermal synthesis and processing of hydrogen titanate nanotubes for nicotine electrochemical sensing

    Science.gov (United States)

    Mersal, Gaber A. M.; Mostafa, Nasser Y.; Omar, Abd-Elkader H.

    2017-08-01

    Hydrogen titanate nanotubes (HTNT) were prepared via acid washing of hydrothermally synthesized sodium titantate nanotube. HTNTs with diameters in the range 7-9 nm and length of several hundred nanometers were annealed at different temperatures and used to modify carbon paste electrode (CPE). Cyclic and square wave voltammetric techniques were used to investigate the behavior of nicotine at HTNT modified carbon paste electrode (HTNTCPE). The nicotine-oxidation reaction over HTNTCPE was irreversible and adsorption process is the rate determining step. HTNTs annealed at 500 °C showed the best response to nicotine. The nicotine concentration was determined at the ideal conditions by square wave voltammetry (SWV). The calibration was linear from 0.1 to 500.0 µmol l-1 with a correlation coefficient of 0.995. The detection limits were found to be 0.005 µmol l-1. The present HTNTCPE was used to the determination of nicotine in two cigarette brands and it showed outstanding performance with respect to detection limit and sensitivity.

  16. Scalable synthesis of aligned carbon nanotubes bundles using green natural precursor: neem oil

    Directory of Open Access Journals (Sweden)

    Kumar Rajesh

    2011-01-01

    Full Text Available Abstract Practical application of aligned carbon nanotubes (ACNTs would have to be determined by a matter of its economical and large-scale preparation. In this study, neem oil (also named Margoaa oil, extracted from the seeds of the neem--Azadirachta indica was used as carbon source to fabricate the bundles of ACNTs. ACNTs have been synthesized by spray pyrolysis of neem oil and ferrocene mixture at 825°C. The major components of neem oil are hydrocarbon with less amount of oxygen, which provided the precursor species in spray pyrolysis growth of CNTs. The bundles of ACNTs have been grown directly inside the quartz tube. The as-grown ACNTs have been characterized through Raman spectroscopy, scanning and transmission electron microscopic (SEM/TEM techniques. SEM images reveal that the bundles of ACNTs are densely packed and are of several microns in length. High-resolution TEM analysis reveals these nanotubes to be multi-walled CNTs. These multi-walled CNTs were found to have inner diameter between 15 and 30 nm. It was found that present technique gives high yield with high density of bundles of ACNTs.

  17. Large-scale synthesis of coiled-like shaped carbon nanotubes using bi-metal catalyst

    Science.gov (United States)

    Krishna, Vemula Mohana; Somanathan, T.; Manikandan, E.; Umar, Ahmad; Maaza, M.

    2018-02-01

    Carbon nanomaterials (CNMs), especially carbon nanotubes (CNTs) with coiled structure exhibit scientifically fascinating. They may be projected as an innovative preference to future technological materials. Coiled carbon nanotubes (c-CNTs) on a large-scale were successfully synthesized with the help of bi-metal substituted α-alumina nanoparticles catalyst via chemical vapor deposition (CVD) technique. Highly spring-like carbon nanostructures were observed by field emission scanning electron microscope (FESEM) examination. Furthermore, the obtained material has high purity, which correlates the X-ray photoelectron spectroscopy (XPS) and energy dispersive X-ray spectroscopy (EDX) analysis. Raman spectroscopy reveals that the carbon multi layers are well graphitized and crystalline, even if they have defects in its structure due to coiled morphology. High-resolution transmission electron microscope (HRTEM) describes internal structure and dia of the product. Ultimately, results support the activity of bi-metal impregnated α-alumina nanoparticles catalyst to determine the high yield, graphitization and internal structure of the material. We have also studied the purified c-CNTs magnetic properties at room temperature and will be an added advantage in several applications.

  18. 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.

  19. 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)

  20. Anisotropic nanomaterials: Synthesis, optical and magnetic properties, and applications

    Science.gov (United States)

    Banholzer, Matthew John

    As nanoscience and nanotechnology mature, anisotropic metal nanostructures are emerging in a variety of contexts as valuable class of nanostructures due to their distinctive attributes. With unique properties ranging from optical to magnetic and beyond, these structures are useful in many new applications. Chapter two discusses the nanodisk code: a linear array of metal disk pairs that serve as surface-enhanced Raman scattering substrates. These multiplexing structures employ a binary encoding scheme, perform better than previous nanowires designs (in the context of SERS) and are useful for both convert encoding and tagging of substrates (based both on spatial disk position and spectroscopic response) as well as biomolecule detection (e.g. DNA). Chapter three describes the development of improved, silver-based nanodisk code structures. Work was undertaken to generate structures with high yield and reproducibility and to reoptimize the geometry of each disk pair for maximum Raman enhancement. The improved silver structures exhibit greater enhancement than Au structures (leading to lower DNA detection limits), convey additional flexibility, and enable trinary encoding schemes where far more unique structures can be created. Chapter four considers the effect of roughness on the plasmonic properties of nanorod structures and introduces a novel method to smooth the end-surfaces of nanorods structures. The smoothing technique is based upon a two-step process relying upon diffusion control during nanowires growth and selective oxidation after each step of synthesis is complete. Empirical and theoretical work show that smoothed nanostructures have superior and controllable optical properties. Chapter five concerns silica-encapsulated gold nanoprisms. This encapsulation allows these highly sensitive prisms to remain stable and protected in solution, enabling their use as class-leading sensors. Theoretical study complements the empirical work, exploring the effect of

  1. The double-edged effects of annealing MgO underlayers on the efficient synthesis of single-wall carbon nanotube forests.

    Science.gov (United States)

    Tsuji, Takashi; Hata, Kenji; Futaba, Don N; Sakurai, Shunsuke

    2017-11-16

    Recently, the millimetre-scale, highly efficient synthesis of single-wall carbon nanotube (SWCNT) forests from Fe catalysts has been reported through the annealing of the magnesia (MgO) underlayer. Here, we report the double-edged effects of underlayer annealing on the efficiency and structure of the SWCNT forest synthesis through a temperature-dependent examination. Our results showed that the efficiency of the SWCNT forests sharply increased with increased underlayer annealing temperatures from 600 °C up to 900 °C due to a temperature-dependent structural modification, characterized by increased grain size and reduced defects, of the MgO underlayer. Beyond this temperature, the SWCNT fraction also decreased as a result of further structural modification of the MgO underlayer. This exemplifies the double-edged effects of annealing. Specifically, for underlayer annealing below 600 °C, the catalyst subsurface diffusion was found to limit the growth efficiency, and for excessively high underlayer annealing temperatures (>900 °C), catalyst coalescence/ripening led to the formation of double-wall carbon nanotubes. As a result, three distinct regions of synthesis were observed: (i) a "low yield" region below a threshold temperature (∼600 °C); (ii) an "increased yield" region from 600 to 900 °C, and (iii) a "saturation" region above 900 °C. The efficient SWCNT forest synthesis could only occur within a specific annealing temperature window as a result of this double-edged effects of underlayer annealing.

  2. Carbon nanotube array actuators

    International Nuclear Information System (INIS)

    Geier, S; Mahrholz, T; Wierach, P; Sinapius, M

    2013-01-01

    Experimental investigations of highly vertically aligned carbon nanotubes (CNTs), also known as CNT-arrays, are the main focus of this paper. The free strain as result of an active material behavior is analyzed via a novel experimental setup. Previous test experiences of papers made of randomly oriented CNTs, also called Bucky-papers, reveal comparably low free strain. The anisotropy of aligned CNTs promises better performance. Via synthesis techniques like chemical vapor deposition (CVD) or plasma enhanced CVD (PECVD), highly aligned arrays of multi-walled carbon nanotubes (MWCNTs) are synthesized. Two different types of CNT-arrays are analyzed, morphologically first, and optically tested for their active characteristics afterwards. One type of the analyzed arrays features tube lengths of 750–2000 μm with a large variety of diameters between 20 and 50 nm and a wave-like CNT-shape. The second type features a maximum, almost uniform, length of 12 μm and a constant diameter of 50 nm. Different CNT-lengths and array types are tested due to their active behavior. As result of the presented tests, it is reported that the quality of orientation is the most decisive property for excellent active behavior. Due to their alignment, CNT-arrays feature the opportunity to clarify the actuation mechanism of architectures made of CNTs. (paper)

  3. Facile Synthesis of Quasi-One-Dimensional Au/PtAu Heterojunction Nanotubes and Their Application as Catalysts in an Oxygen-Reduction Reaction.

    Science.gov (United States)

    Cai, Kai; Liu, Jiawei; Zhang, Huan; Huang, Zhao; Lu, Zhicheng; Foda, Mohamed F; Li, Tingting; Han, Heyou

    2015-05-11

    An intermediate-template-directed method has been developed for the synthesis of quasi-one-dimensional Au/PtAu heterojunction nanotubes by the heterogeneous nucleation and growth of Au on Te/Pt core-shell nanostructures in aqueous solution. The synthesized porous Au/PtAu bimetallic nanotubes (PABNTs) consist of porous tubular framework and attached Au nanoparticles (AuNPs). The reaction intermediates played an important role in the preparation, which fabricated the framework and provided a localized reducing agent for the reduction of the Au and Pt precursors. The Pt7 Au PABNTs showed higher electrocatalytic activity and durability in the oxygen-reduction reaction (ORR) in 0.1 M HClO4 than porous Pt nanotubes (PtNTs) and commercially available Pt/C. The mass activity of PABNTs was 218 % that of commercial Pt/C after an accelerated durability test. This study demonstrates the potential of PABNTs as highly efficient electrocatalysts. In addition, this method provides a facile strategy for the synthesis of desirable hetero-nanostructures with controlled size and shape by utilizing an intermediate template. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Process Parameters for Successful Synthesis of Carbon Nanotubes by Chemical Vapor Deposition: Implications for Chemical Mechanisms and Life-cycle Assessment

    Science.gov (United States)

    Xue, Ke

    Manufacturing of carbon nanotubes (CNTs) via chemical vapor deposition (CVD) calls for thermal treatment associated with gas-phase rearrangement and catalyst deposition to achieve high cost efficiency and limited influence on environmental impact. Taking advantage of higher degree of structure control and economical efficiency, catalytic chemical vapor deposition (CCVD) has currently become the most prevailing synthesis approach for the synthesis of large-scale pure CNTs in past years. Because the synthesis process of CNTs dominates the potential ecotoxic impacts, materials consumption, energy consumption and greenhouse gas emissions should be further limited to efficiently reduce life cycle ecotoxicity of carbon naotubes. However, efforts to reduce energy and material requirements in synthesis of CNTs by CCVD are hindered by a lack of mechanistic understanding. In this thesis, the effect of operating parameters, especially the temperature, carbon source concentration, and residence time on the synthesis were studied to improve the production efficiency in a different angle. Thus, implications on the choice of operating parameters could be provided to help the synthesis of carbon nanotubes. Here, we investigated the typical operating parameters in conditions that have yielded successful CNT production in the published academic literature of over seventy articles. The data were filtered by quality of the resultant product and deemed either "successful" or "unsuccessful" according to the authors. Furthermore, growth rate data were tabulated and used as performance metric for the process whenever possible. The data provided us an opportunity to prompt possible and common methods for practioners in the synthesis of CNTs and motivate routes to achieve energy and material minimization. The statistical analysis revealed that methane and ethylene often rely on thermal conversion process to form direct carbon precursor; further, methane and ethylene could not be the direct

  5. Synthesis and utilization of a novel carbon nanotubes supported nanocables for the adsorption of dyes from aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Wei; Jiang, Xinyu [School of Chemistry and Chemical Engineering, Central South University, Changsha 410083 (China); Chen, Xiaoqing, E-mail: xqchen@csu.edu.cn [School of Chemistry and Chemical Engineering, Central South University, Changsha 410083 (China); Collaborative Innovation Center of Resource-conserving & Environment-friendly Society and Ecological Civilization (China)

    2015-09-15

    Using multiwalled carbon nanotubes(MWCNTs) as mechanical support and glucose as carbon resource, a hydrothermal carbonization route was designed for the synthesis of MWCNTs@carbon nanocables with tunable diameter and length. MWCNTs are firstly used as templates for the formation of carbon-rich composite nanocables, and the diameter of the nanocables could be tailored through adjusting the hydrothermal time or the ratio of MWCNTs and glucose. Owing to abundant superficial oxygen-containing functional groups, porous surface and remarkable reactivity, the as-synthesized nanocables are capable of efficiently adsorbing cationic dye methylene blue (MB) and crystal violet (CV). Furthermore, the optimum adsorption conditions, kinetics, adsorption isotherms and adsorption thermodynamics of dyes were studied systematically. Additionally, the maximum adsorption capacities calculated from data analysis (298.5 mg/g for MB and 228.3 mg/g for CV) are significant higher than those of raw MWCNTs and some other adsorbents reported previously, which provides strong evidence for using MWCNTs@carbon nanocables as adsorbent to remove dyes from aqueous solutions. - Graphical abstract: MWCNTs@carbon nanocables has been successfully fabricated by a hydrothermal carbonization method. The as-synthesized novel samples were used as adsorbents and exhibited high adsorption capacity on MB and CV. - Highlights: • A simple, cost-effective and “green” method for the synthesis of the material. • The diameter and length of the material are relatively easy to control. • The surface has large oxygen-containing groups and preferable chemical reactivity. • Compared with raw MWCNTs and some other adsorbents, the adsorption capacity is much high.

  6. Synthesis of Fe3O4/Pt Nanoparticles Decorated Carbon Nanotubes and Their Use as Magnetically Recyclable Catalysts

    Directory of Open Access Journals (Sweden)

    Hongkun He

    2011-01-01

    Full Text Available We report a facile approach to prepare Fe3O4/Pt nanoparticles decorated carbon nanotubes (CNTs. The superparamagnetic Fe3O4 nanoparticles with average size of 4∼5 nm were loaded on the surfaces of carboxyl groups functionalized CNTs via a high-temperature solution-phase hydrolysis method from the raw material of FeCl3. The synthesis process of magnetic CNTs is green and readily scalable. The loading amounts of Fe3O4 nanopartilces and the magnetizations of the resulting magnetic CNTs show good tunability. The Pt nanopaticles with average size of 2.5 nm were deposited on the magnetic CNTs through a solution-based method. It is demonstrated that the Fe3O4/Pt nanoparticles decorated CNTs have high catalytic activity in the reduction reaction of 4-nitrophenol and can be readily recycled by a magnet and reused in the next reactions with high efficiencies for at least fifteen successive cycles. The novel CNTs-supported magnetically recyclable catalysts are promising in heterogeneous catalysis applications.

  7. A facile synthesis of palladium nanoparticles supported on functional carbon nanotubes and its novel catalysis for ethanol electrooxidation.

    Science.gov (United States)

    Chen, Xiao-mei; Lin, Zhi-jie; Jia, Tian-tian; Cai, Zhi-min; Huang, Xiao-li; Jiang, Ya-qi; Chen, Xi; Chen, Guo-nan

    2009-09-14

    In this study, a novel material, palladium nanoparticles-carboxylic functional carbon nanotubes (PdNPs-CFCNTs), based on PdNPs supported on CFCNTs was synthesized by a facile spontaneous redox method. The material reveals high electrochemical activity and excellent catalytic characteristic for alcohol electrooxidation on a glassy carbon electrode (GCE) in an alkaline medium. The preparation mechanism was studied by the galvanic cell effect between PdCl(4)(2-) and functional defect sites on CFCNTs. Results from UV-visible absorption spectroscopy and electrochemical impedance spectroscopy revealed that the reduction of PdCl(4)(2-) to metallic Pd was successfully achieved. Morphologies of PdNPs supporting on CFCNTs (PdNPs-CFCNTs) were also characterized by transmission electron micrograph. PdNPs-CFCNTs with the best electrocatalytic characteristics were obtained under the condition as: the weight ratio of Pd to CFCNTs was kept at 2:1, the temperature was kept at 70 degrees C in the synthesis, and the scan rate of the applied potential was selected at 60 mV s(-1). The results indicate that PdNPs-CFCNTs could be a great potential material in direct ethanol fuel cells and ethanol sensors.

  8. AuPd Bimetallic Nanocrystals Embedded in Magnetic Halloysite Nanotubes: Facile Synthesis and Catalytic Reduction of Nitroaromatic Compounds

    Directory of Open Access Journals (Sweden)

    Lei Jia

    2017-10-01

    Full Text Available In this research, a facile and effective approach was developed for the preparation of well-designed AuPd alloyed catalysts supported on magnetic halloysite nanotubes (HNTs@Fe3O4@AuPd. The microstructure and the magnetic properties of HNTs@Fe3O4@AuPd were confirmed by transmission electron microscopy (TEM, high resolution TEM (HRTEM, energy-dispersive X-ray spectroscopy (EDS, and vibrating sample magnetometry (VSM analyses. The catalysts, fabricated by a cheap, environmentally friendly, and simple surfactant-free formation process, exhibited high activities during the reduction of 4-nitrophenol and various other nitroaromatic compounds. Moreover, the catalytic activities of the HNTs@Fe3O4@AuPd nanocatalysts were tunable via adjusting the atomic ratio of AuPd during the synthesis. As compared with the monometallic nanocatalysts (HNTs@Fe3O4@Au and HNTs@Fe3O4@Pd, the bimetallic alloyed HNTs@Fe3O4@AuPd nanocatalysts exhibited excellent catalytic activities toward the reduction of 4-nitrophenol (4-NP to 4-aminophenol. Furthermore, the as-obtained HNTs@Fe3O4@AuPd can be recycled several times, while retaining its functionality due to the stability and magnetic separation property.

  9. A facile synthesis of palladium nanoparticles supported on functional carbon nanotubes and its novel catalysis for ethanol electrooxidation

    International Nuclear Information System (INIS)

    Chen Xiaomei; Lin Zhijie; Jia Tiantian; Cai Zhimin; Huang Xiaoli; Jiang Yaqi; Chen Xi; Chen Guonan

    2009-01-01

    In this study, a novel material, palladium nanoparticles-carboxylic functional carbon nanotubes (PdNPs-CFCNTs), based on PdNPs supported on CFCNTs was synthesized by a facile spontaneous redox method. The material reveals high electrochemical activity and excellent catalytic characteristic for alcohol electrooxidation on a glassy carbon electrode (GCE) in an alkaline medium. The preparation mechanism was studied by the galvanic cell effect between PdCl 4 2- and functional defect sites on CFCNTs. Results from UV-visible absorption spectroscopy and electrochemical impedance spectroscopy revealed that the reduction of PdCl 4 2- to metallic Pd was successfully achieved. Morphologies of PdNPs supporting on CFCNTs (PdNPs-CFCNTs) were also characterized by transmission electron micrograph. PdNPs-CFCNTs with the best electrocatalytic characteristics were obtained under the condition as: the weight ratio of Pd to CFCNTs was kept at 2:1, the temperature was kept at 70 o C in the synthesis, and the scan rate of the applied potential was selected at 60 mV s -1 . The results indicate that PdNPs-CFCNTs could be a great potential material in direct ethanol fuel cells and ethanol sensors.

  10. A facile synthesis of palladium nanoparticles supported on functional carbon nanotubes and its novel catalysis for ethanol electrooxidation

    Energy Technology Data Exchange (ETDEWEB)

    Chen Xiaomei; Lin Zhijie; Jia Tiantian; Cai Zhimin; Huang Xiaoli; Jiang Yaqi [Department of Chemistry and Key Laboratory of Analytical Sciences of the Ministry of Education, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005 (China); Chen Xi, E-mail: xichen@xmu.edu.cn [Department of Chemistry and Key Laboratory of Analytical Sciences of the Ministry of Education, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005 (China); State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen 361005 (China); Chen Guonan [Key Laboratory of Analysis and Detection Technology for Food Safety (Fuzhou University), Ministry of Education, Department of Chemistry, Fuzhou University, Fuzhou, Fujian, 350002 (China)

    2009-09-14

    In this study, a novel material, palladium nanoparticles-carboxylic functional carbon nanotubes (PdNPs-CFCNTs), based on PdNPs supported on CFCNTs was synthesized by a facile spontaneous redox method. The material reveals high electrochemical activity and excellent catalytic characteristic for alcohol electrooxidation on a glassy carbon electrode (GCE) in an alkaline medium. The preparation mechanism was studied by the galvanic cell effect between PdCl{sub 4}{sup 2-} and functional defect sites on CFCNTs. Results from UV-visible absorption spectroscopy and electrochemical impedance spectroscopy revealed that the reduction of PdCl{sub 4}{sup 2-} to metallic Pd was successfully achieved. Morphologies of PdNPs supporting on CFCNTs (PdNPs-CFCNTs) were also characterized by transmission electron micrograph. PdNPs-CFCNTs with the best electrocatalytic characteristics were obtained under the condition as: the weight ratio of Pd to CFCNTs was kept at 2:1, the temperature was kept at 70 {sup o}C in the synthesis, and the scan rate of the applied potential was selected at 60 mV s{sup -1}. The results indicate that PdNPs-CFCNTs could be a great potential material in direct ethanol fuel cells and ethanol sensors.

  11. Synthesis and characterization of hydrotalcite-hydroxyapatite material doped with carbon nanotubes and its application in catalysis of transesterification reaction

    International Nuclear Information System (INIS)

    Rodrigues, E.; Barros, T.; Pereira, C.; Almeida, O.; Brasil, H.; Reis, M.A L. dos

    2018-01-01

    The aim of this study was to synthesize and characterize hydrotalcite-hydroxyapatite (HTHAp) material doped with three different proportions (1, 5 and 15% w/w) of carbon nanotubes (NTC) in order to evaluate its potential as a heterogeneous catalyst in the soybean oil methanolysis reaction. The synthesis of the HTHAp material was performed by the co-precipitation method (10≤pH≤ 11) with ultrasonic homogenization and hydrothermal treatment at 80 °C. XRD, SEM/EDS, FT-IR, Raman, N 2 physisorption and TG/DTA were the characterization techniques performed. The sample HTHAp1NTC, doped at 1% w/w, was tested as a catalyst under two temperature conditions (180 and 240 °C), 4 h reaction time, 2.5% catalyst loading and alcohol:oil ratio of 12:1. Doping contributed to improve structural, morphological and thermal stability properties of HTHAp material. The yield results achieved 35.2% (180 °C) and 40.5% (240 °C) qualifying the HTHAp material doped with CNT as a potential catalyst in the transesterification reaction. (author)

  12. Controlled synthesis of 2D Au nanostructure assembly with the assistance of sulfonated polyaniline nanotubes

    International Nuclear Information System (INIS)

    Yuan Junhua; Wang Zhijuan; Zhang Qixian; Han, Dongxue; Zhang Yuanjian; Shen Yanfei; Niu Li

    2006-01-01

    A wet chemical approach is used successfully to produce nanostructured Au material by the reduction of sulfonated polyaniline (SPANI) nanotubes. The Au nanostructures obtained are composed of single crystal Au nanoplates, which are aggregated layer-by-layer into stacks or edge-on-face into clusters at various conditions. The Au nanoplate diameter and thickness can be conveniently controlled in the range of 100 nm to 2 μm and 10 to 30 nm, respectively, with no accompanying single Au nanoparticles being observed. The formation of the Au nanostructures was controlled by the degradation of SPANI. The gradually and slowly released segments of SPANI served as the reductant during the growth of the 2D Au nanostructures

  13. Effect of growth pressure on the synthesis of vertically aligned carbon nanotubes and their growth termination.

    Science.gov (United States)

    Park, Sangeun; Song, Wooseok; Kim, Yooseok; Song, Inkyung; Kim, Sung Hwan; Lee, Su Il; Jang, Sung Won; Parkl, Chong-Yun

    2014-07-01

    When vertically aligned carbon nanotubes (VACNTs) are synthesized by thermal chemical vapor deposition (TCVD), their structural features such as height and density can be determined by TCVD growth conditions. In this study we investigated the effect of growth pressure on the structural features of VACNTs. Changes in growth pressure significantly affected the height, density, and crystalinity of synthesized VACNTs. In addition, we suggest that the growth termination of VACNTs could be due to the lack of carbon feedstock supply to the center of the VACNT film induced by the pressure-dependent adsorption of amorphous carbon at the edge of the VACNT film. In addition, the field emission characteristics of the VACNT film were carried out. The turn-on voltage of the VACNT film was 1.62 V/microm and the field enhancement factor (beta) was 2478. These results provide useful information for practical applications of VACNTs, such as field emission display and X-ray source.

  14. Synthesis and Characterization of Multiwalled Carbon Nanotubes/Poly(HEMA-co-MMA) by Utilizing Click Chemistry.

    Science.gov (United States)

    Bach, Long Giang; Cao, Xuan Thang; Islam, Md Rafiqul; Jeong, Yeon Tae; Kim, Jong Su; Lim, Kwon Taek

    2016-03-01

    The hybrid material consisting of multi walled carbon nanotubes (MWNTs) and poly(2-hydroxyethylmethacrylate-co-methylmethacrylate) [poly(HEMA-co-MMA)] was synthesized by a combination of RAFT and Click chemistry. In the primary stage, the copolymer poly(HEMA-co-MMA) was prepared by applying RAFT technique. Alkynyl side groups were incorporated onto the poly(HEMA-co-MMA) backbone by esterification reaction. Then, MWNTs-N3 was prepared by treating MWNTs with 4-azidobutylamine. The click coupling reaction between azide-functionalized MWNTs (MWNTs-N3) and the alkyne-functionalized random copolymer ((HEMA-co-MMA)-Alkyne) with the Cu(I)-catalyzed [3+2] Huisgen cycloaddition afforded the hybrid compound. The structure and properties of poly(MMA-co-HEMA)-g-MWNTs were investigated by FT-IR, EDX and TGA measurements. The copolymer brushes were observed to be immobilized onto the functionalized MWNTs by SEM and TEM analysis.

  15. Nanosized Magnesium Electrochemically Deposited on a Carbon Nanotubes Suspension: Synthesis and Hydrogen Storage

    Directory of Open Access Journals (Sweden)

    Chaoqi Shen

    2017-10-01

    Full Text Available Herein, we report on a novel method for deposition of magnesium (Mg nanoparticles at the surface of carbon materials. Through the suspension of carbon nanotubes (CNTs in an electrolyte containing di-n-butylmagnesium as a precursor, Mg nanoparticles were effectively deposited at the surface of the CNTs as soon as these touched the working electrode. Through this process, CNTs supported Mg particles as small as 1 nm were synthesized and the distribution of the nanoparticles was found to be influenced by the concentration of the CNTs in the electrolyte. Hydrogenation of these nanoparticles at 100°C was found to lead to low temperature hydrogen release starting at 150°C, owing to shorter diffusion paths and higher hydrogen mobility in small Mg particles. However, these hydrogen properties drastically degraded as soon as the hydrogenation temperature exceeded 200°C and this may be related to the low melting temperature of ultrasmall Mg particles.

  16. A new method synthesis polyaniline/multi-walled carbon nanotube composites for supercapacitor electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Pan, J.; Wei, X.; Zhou, S.P. [Shandong Univ. of Technology, Zibo (China). School of Chemical Engineering

    2010-07-01

    A series of polyaniline multi-walled nanotube (PANIMWNT) composite films were prepared using an in situ polymerization technique. Scanning electron microscopy (SEM) was used to characterize the morphology and microstructure of the samples. Cyclic voltammetry (CV), impedance spectroscopy, and galvanostatic charge/discharge analyses were used to determine the electrochemical properties of the PANIMWNT films in a 3-electrode system. The electrochemical performance of PANI, PANIMWNT, and MWNT film performances was then compared. Results of the study showed that the PANI electrodes showed a much higher capacitance than the MWNT and PANIMWNT electrodes. Both the PANI and PANIMWNT nanocomposites showed good electrochemical capacitance. The improved performance of the electrodes was attributed to the presence of sodium hypochlorite (NaClO). 5 refs.

  17. Nanosized Magnesium Electrochemically Deposited on a Carbon Nanotubes Suspension: Synthesis and Hydrogen Storage

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Chaoqi; Aguey-Zinsou, Kondo-Francois, E-mail: f.aguey@unsw.edu.au [MERLin, School of Chemical Engineering, The University of New South Wales, Sydney, NSW (Australia)

    2017-10-17

    Herein, we report on a novel method for deposition of magnesium (Mg) nanoparticles at the surface of carbon materials. Through the suspension of carbon nanotubes (CNTs) in an electrolyte containing di-n-butylmagnesium as a precursor, Mg nanoparticles were effectively deposited at the surface of the CNTs as soon as these touched the working electrode. Through this process, CNTs supported Mg particles as small as 1 nm were synthesized and the distribution of the nanoparticles was found to be influenced by the concentration of the CNTs in the electrolyte. Hydrogenation of these nanoparticles at 100°C was found to lead to low temperature hydrogen release starting at 150°C, owing to shorter diffusion paths and higher hydrogen mobility in small Mg particles. However, these hydrogen properties drastically degraded as soon as the hydrogenation temperature exceeded 200°C and this may be related to the low melting temperature of ultrasmall Mg particles.

  18. Templated Synthesis of Single-Walled Carbon Nanotubes with Specific Structure.

    Science.gov (United States)

    Yang, Feng; Wang, Xiao; Li, Meihui; Liu, Xiyan; Zhao, Xiulan; Zhang, Daqi; Zhang, Yan; Yang, Juan; Li, Yan

    2016-04-19

    Single-walled carbon nanotubes (SWNTs) have shown great potential in various applications attributed to their unique structure-dependent properties. Therefore, the controlled preparation of chemically and structurally pristine SWNTs is a crucial issue for their advanced applications (e.g., nanoelectronics) and has been a great challenge for two decades. Epitaxial growth from well-defined seeds has been shown to be a promising strategy to control the structure of SWNTs. Segments of carbon nanotubes, including short pipes from cutting of preformed nanotubes and caps from opening of fullerenes or cyclodehydrogenation of polycyclic hydrocarbon precursors, have been used as the seeds to grow SWNTs. Single-chirality SWNTs were obtained with both presorted chirality-pure SWNT segments and end caps obtained from polycyclic hydrocarbon molecules with designed structure. The main challenges of nanocarbon-segment-seeded processes are the stability of the seeds, yield, and efficiency. Catalyst-mediated SWNT growth is believed to be more efficient. The composition and morphology of the catalyst nanoparticles have been widely reported to affect the chirality distribution of SWNTs. However, chirality-specific SWNT growth is hard to achieve by alternating catalysts. The specificity of enzyme-catalyzed reactions brings us an awareness of the essentiality of a unique catalyst structure for the chirality-selective growth of SWNTs. Only catalysts with the desired atomic arrangements in their crystal planes can act as structural templates for chirality-specific growth of SWNTs. We have developed a new family of catalysts, tungsten-based intermetallic compounds, which have high melting points and very special crystal structures, to facilitate the growth of SWNTs with designed chirality. By the use of W6Co7 catalysts, (12,6) SWNTs were directly grown with purity higher than 92%. Both high-resolution transmission electron microscopy measurements and density functional theory simulations

  19. Synthesis of carbon nanotubes by CCVD of natural gas using hydrotreating catalysts

    Directory of Open Access Journals (Sweden)

    Ahmed E. Awadallah

    2012-12-01

    Full Text Available Carbon nanotubes have been successfully synthesized using the catalytic chemical vapor deposition (CCVD technique over typical refining hydrotreating catalysts (hydrodesulfurization and hydrodenitrogenation containing Ni–Mo and Co–Mo supported on Al2O3 catalysts at 700°C in a fixed bed horizontal reactor using natural gas as a carbon source. The catalysts and the as-grown CNTs were characterized by transmission electron microscopy, HRTEM, X-ray diffraction patterns, EDX and TGA–DTG. The obtained data clarified that the Ni–Mo catalyst gives higher yield, higher purity and selectivity for CNTs compared to Co–Mo catalyst. XRD, TEM and TGA reveal also that the Ni–Mo catalyst produces mostly CNTs with different diameters whereas the Co–Mo catalyst produces largely amorphous carbon.

  20. The effect of synthesis conditions on the formation of titanate nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Qamar, M.; Yoon, C. R.; Oh, H. J.; Kim, S. J. [Sejong University, Seoul (Korea, Republic of); Kim, D. H.; Lee, K. S. [Hanyang University, Seoul (Korea, Republic of); Lee, H. G. [Korea Polytechnic University, Siheung (Korea, Republic of)

    2006-10-15

    The TiO{sub 2} sol was prepared hydrothermally in an autoclave from aqueous TiOCl{sub 2} solutions as a starting precursor. Hollow fibers were obtained when the sol-gel-derived TiO{sub 2} sol was treated chemically with a NaOH solution and subsequently heated in the autoclave under various conditions. A systematic analysis of the influence of different NaOH concentrations on the formation of nanotubes was carried out. The details of the nanotubular structure were investigated by using transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), Brauner-Emmett-Teller (BET) surface area, and photoluminescence (PL) measurements. From the TEM images, the outer and the inner diameters of the tubes were measured to be about 8 and 4 nm, respectively, the lengths were measured to be several hundreds of nanometers.

  1. Low temperature synthesis of coiled carbon nanotubes and their magnetic properties

    Science.gov (United States)

    Krishna, Vemula Mohana; Somanathan, T.; Manikandan, E.

    2018-04-01

    In this paper, coiled like structure of carbon nanotubes (c-CNTs) have been effectively grown on bi-metal substituted α-alumina nanoparticles catalyst by chemical vapor deposition (CVD) system. Highly graphitized and dense bundles of carbon product were attained at a low temperature of 550 °C. The coiled carbon nanostructures in very longer lengths were noticed by field emission scanning electron microscope (FESEM) observation. Furthermore, high purity material was achieved, which correlates the energy dispersive x-ray spectroscopy (EDX) analysis. High resolution transmission electron microscope (HRTEM) revealed the diameter and graphitization of coiled structures. The superparamagnetic like behavior was observed at room temperature for the as-synthesized product, which was found by VSM investigation.

  2. Selective optical switching of interface-coupled relaxation dynamics in carbon nanotube-Si heterojunctions

    KAUST Repository

    Ponzoni, Stefano

    2014-10-16

    By properly tuning the photon energy of a femtosecond laser pump, we disentangle, in carbon nanotube-Si (CNT/Si) heterojunctions, the fast relaxation dynamics occurring in CNT from the slow repopulation dynamics due to hole charge transfer at the junction. In this way we are able to track the transfer of the photogenerated holes from the Si depletion layer to the CNT layer, under the action of the built-in heterojunction potential. This also clarifies that CNT play an active role in the junction and do not act only as channels for charge collection and transport.

  3. Selective optical switching of interface-coupled relaxation dynamics in carbon nanotube-Si heterojunctions

    KAUST Repository

    Ponzoni, Stefano; Galimberti, Gianluca; Sangaletti, L.; Castrucci, Paola; Del Gobbo, Silvano; Morbidoni, Maurizio; Scarselli, Manuela A.; Pagliara, Stefania

    2014-01-01

    By properly tuning the photon energy of a femtosecond laser pump, we disentangle, in carbon nanotube-Si (CNT/Si) heterojunctions, the fast relaxation dynamics occurring in CNT from the slow repopulation dynamics due to hole charge transfer at the junction. In this way we are able to track the transfer of the photogenerated holes from the Si depletion layer to the CNT layer, under the action of the built-in heterojunction potential. This also clarifies that CNT play an active role in the junction and do not act only as channels for charge collection and transport.

  4. Synthesis of MnO{sub 2}/short multi-walled carbon nanotube nanocomposite for supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jinhui; Wang, Yanhui; Zang, Jianbing, E-mail: diamondzjb@163.com; Xin, Guoxiang; Ji, Huiying; Yuan, Yungang

    2014-01-15

    Multi-walled carbon nanotubes (MWNTs) were selectively etched in molten nitrate to produce short MWNTs (s-MWNTs). MnO{sub 2}/s-MWNT nanocomposite was synthesized by a reduction of potassium permanganate under microwave irradiation. For comparative purpose, MnO{sub 2}/MWNT nanocomposite was also synthesized and investigated for its physical and electrochemical performance. Uniform and conformal MnO{sub 2} coatings were more easily formed on the surfaces of individual s-MWNTs. MnO{sub 2}/s-MWNT nanocomposite estimated by cyclic voltammetry (CV) in 0.5 M Na{sub 2}SO{sub 4} aqueous solution had the specific capacitance as high as 392.1 F g{sup −1} at 2 mV s{sup −1}. This value was more than 48.9% larger than MnO{sub 2}/s-MWNT nanocomposite. In addition, MnO{sub 2}/s-MWNT nanocomposite was also examined by repeating the CV test at a scan rate of 50 mV s{sup −1}, exhibiting an excellent cycling stability along with 99.2% specific capacitance retained after 1000 cycles. Therefore, MnO{sub 2}/s-MWNT nanocomposite is a promising electrode material in the supercapacitors. - Highlights: • Multi-walled carbon nanotubes are etched in molten nitrate to produce short MWNTs. • S-MWNTs can form more stable suspensions than did the pristine MWNTs. • Nano-scaled MnO{sub 2} is more effectively dispersed on the surface of the s-MWNTs. • This microstructure promotes the electrical conductivity of the electrode. • The electrode exhibits high specific capacitance and a cycle stability.

  5. Fourier synthesis of asymmetrical optical potentials for atoms

    International Nuclear Information System (INIS)

    Ritt, G.

    2007-01-01

    In this work a dissipationless asymmetrical optical potential for cold atoms was produced. In a first step a new type of optical lattice was generated, whose spatial periodicity only corresponds to a quarter of the wavelength of the light used for the generation. This corresponds to the half of the periodicity of a conventional optical lattice, which is formed by the light of the same wavelength. The generation of this new type of optical lattice was reached by the use of two degenerated raman transitions. Virtual processes occur, in which four photons are involved. In conventional optical lattices however virtual two-photon processes occur. By spatially superimposing this optical lattice with a conventional optical lattice an asymmetrical optical potential could be formed. By diffraction of a Bose Einstein condensate of rubidium atoms at the transient activated asymmetrical potential the asymmetrical structure was proven. (orig.)

  6. Measurement of carbon nanotube microstructure relative density by optical attenuation and observation of size-dependent variations.

    Science.gov (United States)

    Park, Sei Jin; Schmidt, Aaron J; Bedewy, Mostafa; Hart, A John

    2013-07-21

    Engineering the density of carbon nanotube (CNT) forest microstructures is vital to applications such as electrical interconnects, micro-contact probes, and thermal interface materials. For CNT forests on centimeter-scale substrates, weight and volume can be used to calculate density. However, this is not suitable for smaller samples, including individual microstructures, and moreover does not enable mapping of spatial density variations within the forest. We demonstrate that the relative mass density of individual CNT microstructures can be measured by optical attenuation, with spatial resolution equaling the size of the focused spot. For this, a custom optical setup was built to measure the transmission of a focused laser beam through CNT microstructures. The transmittance was correlated with the thickness of the CNT microstructures by Beer-Lambert-Bouguer law to calculate the attenuation coefficient. We reveal that the density of CNT microstructures grown by CVD can depend on their size, and that the overall density of arrays of microstructures is affected significantly by run-to-run process variations. Further, we use the technique to quantify the change in CNT microstructure density due to capillary densification. This is a useful and accessible metrology technique for CNTs in future microfabrication processes, and will enable direct correlation of density to important properties such as stiffness and electrical conductivity.

  7. Synthesis of calcium-phosphorous doped TiO{sub 2} nanotubes by anodization and reverse polarization: A promising strategy for an efficient biofunctional implant surface

    Energy Technology Data Exchange (ETDEWEB)

    Alves, Sofia A., E-mail: sofiafonso@msn.com [CMEMS – Center of MicroElectroMechanical Systems, Department of Mechanical Engineering, University of Minho, 4800-058 Guimarães (Portugal); IBTN/US – American Branch of the Institute of Biomaterials, Tribocorrosion and Nanomedicine, UIC College of Dentistry, 60612 Chicago, IL (United States); Patel, Sweetu B. [IBTN/US – American Branch of the Institute of Biomaterials, Tribocorrosion and Nanomedicine, UIC College of Dentistry, 60612 Chicago, IL (United States); Department of Mechanical Engineering, Michigan Technological University, 49931 Houghton, MI (United States); Sukotjo, Cortino [IBTN/US – American Branch of the Institute of Biomaterials, Tribocorrosion and Nanomedicine, UIC College of Dentistry, 60612 Chicago, IL (United States); Departmenmt of Restorative Dentistry, University of Illinois at Chicago, 60612 Chicago, IL (United States); Mathew, Mathew T. [IBTN/US – American Branch of the Institute of Biomaterials, Tribocorrosion and Nanomedicine, UIC College of Dentistry, 60612 Chicago, IL (United States); Department of Orthopedic Surgery, Rush University Medical Center, 60612 Chicago, IL (United States); Department of Biomedical Science, UIC School of Medicine at Rockford, 61107 Rockford, IL (United States); Filho, Paulo N. [IBTN/Br – Brazilian Branch of the Institute of Biomaterials, Tribocorrosion and Nanomedicine, UNESP – Universidade Estadual Paulista, Faculdade de Ciências, 17033-360 Bauru, São Paulo (Brazil); Faculdade de Ciências, Departamento de Física, UNESP - Universidade Estadual Paulista, 17033-360 Bauru, São Paulo (Brazil); Celis, Jean-Pierre [Department of Materials Engineering, KU Leuven, 3001 Leuven (Belgium); and others

    2017-03-31

    Highlights: • A new surface modification methodology for bio-functionalization of TiO2 NTs is addressed • Bone-like structured TiO2 nanotubular surfaces containing Ca and P were synthesized. • Ca/P-doped TiO2 NTs enhanced adhesion and proliferation of osteoblastic-like cells. • The bio-functionalization granted improved bio-electrochemical stability to TiO2 NTs. - Abstract: The modification of surface features such as nano-morphology/topography and chemistry have been employed in the attempt to design titanium oxide surfaces able to overcome the current dental implants failures. The main goal of this study is the synthesis of bone-like structured titanium dioxide (TiO{sub 2}) nanotubes enriched with Calcium (Ca) and Phosphorous (P) able to enhance osteoblastic cell functions and, simultaneously, display an improved corrosion behavior. To achieve the main goal, TiO{sub 2} nanotubes were synthetized and doped with Ca and P by means of a novel methodology which relied, firstly, on the synthesis of TiO{sub 2} nanotubes by anodization of titanium in an organic electrolyte followed by reverse polarization and/or anodization, in an aqueous electrolyte. Results show that hydrophilic bone-like structured TiO{sub 2} nanotubes were successfully synthesized presenting a highly ordered nano-morphology characterized by non-uniform diameters. The chemical analysis of such nanotubes confirmed the presence of CaCO{sub 3}, Ca{sub 3}(PO{sub 4}){sub 2}, CaHPO{sub 4} and CaO compounds. The nanotube surfaces submitted to reverse polarization, presented an improved cell adhesion and proliferation compared to smooth titanium. Furthermore, these surfaces displayed a significantly lower passive current in artificial saliva, and so, potential to minimize their bio-degradation through corrosion processes. This study addresses a very simple and promising multidisciplinary approach bringing new insights for the development of novel methodologies to improve the outcome of osseointegrated

  8. Synthesis of stable TiO2 nanotubes: effect of hydrothermal treatment, acid washing and annealing temperature.

    Science.gov (United States)

    López Zavala, Miguel Ángel; Lozano Morales, Samuel Alejandro; Ávila-Santos, Manuel

    2017-11-01

    Effect of hydrothermal treatment, acid washing and annealing temperature on the structure and morphology of TiO 2 nanotubes during the formation process was assessed. X-ray diffraction, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy analysis were conducted to describe the formation and characterization of the structure and morphology of nanotubes. Hydrothermal treatment of TiO 2 precursor nanoparticles and acid washing are fundamental to form and define the nanotubes structure. Hydrothermal treatment causes a change in the crystallinity of the precursor nanoparticles from anatase phase to a monoclinic phase, which characterizes the TiO 2 nanosheets structure. The acid washing promotes the formation of high purity nanotubes due to Na + is exchanged from the titanate structure to the hydrochloric acid (HCl) solution. The annealing temperature affects the dimensions, structure and the morphology of the nanotubes. Annealing temperatures in the range of 400 °C and 600 °C are optimum to maintain a highly stable tubular morphology of nanotubes. Additionally, nanotubes conserve the physicochemical properties of the precursor Degussa P25 nanoparticles. Temperatures greater than 600 °C alter the morphology of nanotubes from tubular to an irregular structure of nanoparticles, which are bigger than those of the precursor material, i.e., the crystallinity turn from anatase phase to rutile phase inducing the collapse of the nanotubes.

  9. Hydrothermal synthesis of TiO2 Nanotubes: Microwave heating versus conventional heating

    CSIR Research Space (South Africa)

    Sikhwivhilu, LM

    2010-01-01

    Full Text Available The influence of the method of synthesis in the properties of the tubular structures derived from TiO2 was investigated using XRD, SEM and BET analysis. The use of microwave irradiation resulted in the formation of TiO2 tubes comprising anatase...

  10. Microwave synthesis of Titanium Dioxide nanotubes for use in water treatment

    CSIR Research Space (South Africa)

    Sikhwivhilu, L

    2010-09-01

    Full Text Available various methods have been used to synthesise Titanium Dioxide (TiO2) (also known as Titania) nanoparticles hydrothermal synthesis in the presence of a base solution, has proved to be an effective approach to prepare 1D nanostructures of TiO2...

  11. Co9S8 nanotubes: facile synthesis and application in the catalytic ...

    Indian Academy of Sciences (India)

    spectrometry and scanning electron microscopy. The result displays that the ... research interest due to their potential applications in cata- lysis, optical, electronic ... for catalysts, supercapacitors and Li-ion batteries [5–8]. In recent years, cobalt ...

  12. Synthesis of hydroxyapatite/multi-walled carbon nanotubes for the removal of fluoride ions from solution

    International Nuclear Information System (INIS)

    Ruan, Zhongyuan; Tian, Yaxi; Ruan, Jifu; Cui, Guijia; Iqbal, Kanwal; Iqbal, Anam; Ye, Herui; Yang, Zhangzhong; Yan, Shiqiang

    2017-01-01

    Graphical abstract: Hydroxyapatite nucleated and grown on Multi-walled carbon nanotubes (HA-MWCNTs) showed enhanced fluoride removal performance. - Highlights: • Noval HA nanoparticles and HA-MWCNTs composites were successfully synthesized for the first time. • The synthesized HA-MWCNTs composites exhibited a higher defluoridation capacity of 39.22 mg g"−"1. • It could reduced the fluoride concentration of the real waste water from 8.79 mg L"−"1 to approximately 0.25 mg L"−"1. - Abstract: A novel composite material, hydroxyapatite (HA)-multi-walled carbon nanotubes (MWCNTs), was prepared using a simple in-situ sol-gel method, and was used for the first time to remove fluoride from water. The novel HA-MWCNTs were characterized using TEM, FT-IR, BET and XRD analysis. The TEM and SAED results revealed that the MWCNTs were uniformly encapsulated by hydroxyapatite nanoparticles. The synthesized HA-MWCNTs had a high specific surface area (180.504 m"2 g"−"1), with an average pore width (14.607 nm) and pore volume (0.774 cm"3 g"−"1), which produced a defluoridation capacity (DC) of 30.22 mgF"− g"−"1. This value was greater than unmodified hydroxyapatite (HA), which exhibited a larger specific surface area (172.233 m"2 g"−"1) and an excellent DC of 17.80 mgF"− g"−"1. A number of pertinent parameters that could affect the defluoridation performance of the HA/MWCNTs including weight ratios of the two key materials, solution pH and competing anions were carefully and comprehensively examined. It was found that the adsorption results followed the Langmuir and Freundlich isotherm model, and the sorption kinetics of the F"− appeared to exhibit a pseudo second order. Moreover, the adsorption reaction was spontaneous and endothermic and appeared to exhibit a higher initial adsorption rate. This reaction appeared to occur result from both anion exchange and electrostatic interactions. When the HA-MWCNTs (MH6) were at an adsorbent dose of 2.0 g L"−"1

  13. Synthesis of hydroxyapatite/multi-walled carbon nanotubes for the removal of fluoride ions from solution

    Energy Technology Data Exchange (ETDEWEB)

    Ruan, Zhongyuan; Tian, Yaxi [College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000 (China); Ruan, Jifu [Chemistry Teaching and Research Group, No.1 Middle School of Queshan, Henan 463200 (China); Cui, Guijia; Iqbal, Kanwal; Iqbal, Anam [College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000 (China); Ye, Herui; Yang, Zhangzhong [Northwest Regional Office of Nuclear and Radiation Safety, Ministry of Environmental Protection, Lanzhou 730000 (China); Yan, Shiqiang, E-mail: yansq@lzu.edu.cn [College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000 (China)

    2017-08-01

    Graphical abstract: Hydroxyapatite nucleated and grown on Multi-walled carbon nanotubes (HA-MWCNTs) showed enhanced fluoride removal performance. - Highlights: • Noval HA nanoparticles and HA-MWCNTs composites were successfully synthesized for the first time. • The synthesized HA-MWCNTs composites exhibited a higher defluoridation capacity of 39.22 mg g{sup −1}. • It could reduced the fluoride concentration of the real waste water from 8.79 mg L{sup −1} to approximately 0.25 mg L{sup −1}. - Abstract: A novel composite material, hydroxyapatite (HA)-multi-walled carbon nanotubes (MWCNTs), was prepared using a simple in-situ sol-gel method, and was used for the first time to remove fluoride from water. The novel HA-MWCNTs were characterized using TEM, FT-IR, BET and XRD analysis. The TEM and SAED results revealed that the MWCNTs were uniformly encapsulated by hydroxyapatite nanoparticles. The synthesized HA-MWCNTs had a high specific surface area (180.504 m{sup 2} g{sup −1}), with an average pore width (14.607 nm) and pore volume (0.774 cm{sup 3} g{sup −1}), which produced a defluoridation capacity (DC) of 30.22 mgF{sup −} g{sup −1}. This value was greater than unmodified hydroxyapatite (HA), which exhibited a larger specific surface area (172.233 m{sup 2} g{sup −1}) and an excellent DC of 17.80 mgF{sup −} g{sup −1}. A number of pertinent parameters that could affect the defluoridation performance of the HA/MWCNTs including weight ratios of the two key materials, solution pH and competing anions were carefully and comprehensively examined. It was found that the adsorption results followed the Langmuir and Freundlich isotherm model, and the sorption kinetics of the F{sup −} appeared to exhibit a pseudo second order. Moreover, the adsorption reaction was spontaneous and endothermic and appeared to exhibit a higher initial adsorption rate. This reaction appeared to occur result from both anion exchange and electrostatic interactions. When the

  14. A new ion exchange behavior of protonated titanate nanotubes after deprotonation and the study on their morphology and optical properties

    International Nuclear Information System (INIS)

    Zhang Huibin; Cao Lixin; Liu Wei; Su Ge

    2012-01-01

    Graphical abstract: The morphological transformation of protonated titanate nanotubes under alkali solution before ion exchange (a) and after ion exchange (b). Highlights: ► A novel ion exchange behavior of protonated titanate nanotubes after deprotonation. ► The exchangeability of protonated titanate nanotubes are not as inert as past reported. ► The tube walls of H 2 Ti 3 O 7 nanotubes is observed to get loosened after ion exchange. ► The paper proves a new and easy way to modify protonated titanate nanotubes. - Abstract: After the deprotonation of protonated titanate nanotubes (H 2 Ti 3 O 7 ), we observed a novel ion exchange behavior on them. In the past literatures, protonated titanate nanotubes prepared via hydrothermal method have been reported with a poor exchangeability which may due to the chemical bonding of interlayer protons to nearby oxygen atoms. However, in this experiment under alkali environment (pH > 10), protonated titanate nanotubes exhibited a vast ion exchange capacity toward [Co(NH 3 ) 6 ] 2+ . This interesting phenomenon is contrary to the past reports which found protonated titanate nanotubes hardly could be ionexchanged by objective cations. This paper proves the deprotonation process on H 2 Ti 3 O 7 nanotubes sufficiently facilitates the diffusion of metal complex cations into protonated titanate nanotubes and significantly changes their ion exchange capacity. As a consequence of cabalt intercalting via ion exchange, the tube wall of H 2 Ti 3 O 7 nanotubes is observed to get loosened. Additionally, the exciton concentrations corresponding to the nanotube surface states are discussed in the paper.

  15. Synthesis and optical properties of biphenylene ethynylene co ...

    Indian Academy of Sciences (India)

    The absorption and photoluminescence spectra of the polymers, P1, P2 and P5 showed .... Microanalyses were performed at the ... signals were passed through a second monochromator .... 3.1 Synthesis and characterization of polymers and.

  16. Substrate bias induced synthesis of flowered-like bunched carbon nanotube directly on bulk nickel

    Energy Technology Data Exchange (ETDEWEB)

    Bisht, Atul [Polymorphic Carbon Thin Films Group, Physics of Energy Harvesting Division, CSIR-National Physical Laboratory, Dr. K. S. Krishnan Marg, New Delhi 110012 (India); Academy of Scientific and Innovative Research (AcSIR), CSIR Campus, New Delhi 110012 (India); Chockalingam, S. [Polymorphic Carbon Thin Films Group, Physics of Energy Harvesting Division, CSIR-National Physical Laboratory, Dr. K. S. Krishnan Marg, New Delhi 110012 (India); Panwar, O.S., E-mail: ospanwar@mail.nplindia.ernet.in [Polymorphic Carbon Thin Films Group, Physics of Energy Harvesting Division, CSIR-National Physical Laboratory, Dr. K. S. Krishnan Marg, New Delhi 110012 (India); Academy of Scientific and Innovative Research (AcSIR), CSIR Campus, New Delhi 110012 (India); Kesarwani, A.K. [Polymorphic Carbon Thin Films Group, Physics of Energy Harvesting Division, CSIR-National Physical Laboratory, Dr. K. S. Krishnan Marg, New Delhi 110012 (India); Academy of Scientific and Innovative Research (AcSIR), CSIR Campus, New Delhi 110012 (India); Singh, B.P. [Physics and Engineering of Carbon Materials, Division of Materials Physics and Engineering, CSIR-National Physical Laboratory, Dr. K. S. Krishnan Marg, New Delhi 110012 (India); Academy of Scientific and Innovative Research (AcSIR), CSIR Campus, New Delhi 110012 (India); Singh, V.N. [Electron and Ion Microscopy, Sophisticated and Analytical Instruments, CSIR-National Physical Laboratory, Dr. K. S. Krishnan Marg, New Delhi 110012 (India); Academy of Scientific and Innovative Research (AcSIR), CSIR Campus, New Delhi 110012 (India)

    2016-02-15

    Highlights: • Flowered-like bunched MWCNTs have been synthesized by MW PECVD technique. • Effect of substrate bias on the properties of MWCNT has been studied. • Minimum E{sub T} = 1.9 V/μm with β = 4770 has been obtained in the film deposited at −350 V. - Abstract: This paper reports the effect of substrate bias on the multiwalled carbon nanotube (MWCNT) deposited on nickel foil by microwave plasma enhanced chemical vapor deposition technique. The MWCNTs have been characterized by the scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), Raman spectroscopy, field emission and current–voltage characteristic of the heterojunction diode. The SEM images exhibit unique hierarchical flowered-like bunched and conformally coated MWCNTs. Substrate bias induced ion bombardment helps in the enhancement of hydrocarbon dissociation and is responsible for flowered-like MWCNTs growth. The HRTEM micrographs show the base growth mechanism for MWCNTs. The value of turn on field for emission decreases from 5.5 to 1.9 V/μm and field enhancement factor increases from 927 to 4770, respectively, with the increase of substrate bias. The diode ideality factor of CNT/ n-Si heterojunction is evaluated as 2.4 and the on/off current ratio is found to be 7 at ±2 V, respectively.

  17. Synthesis of ZnO coated multi-walled carbon nanotubes and their antibacterial activities

    Energy Technology Data Exchange (ETDEWEB)

    Sui, Minghao, E-mail: suiminghao.sui@gmail.com; Zhang, Lingdian, E-mail: 970864427@qq.com; Sheng, Li, E-mail: shengli1971@gmail.com; Huang, Shuhang, E-mail: hsh880813@qq.com; She, Lei, E-mail: selery1989@163.com

    2013-05-01

    ZnO coated multi-walled carbon nanotubes (ZnO/MWCNTs) were prepared and evaluated for their application potentials as an antimicrobial material for simultaneous concentrating and inactivating pathogenic bacteria. X-ray energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), and X-ray photoelectron spectra (XPS) were used to characterize the ZnO/MWCNTs. Escherichia coli (E. coli) was employed as the target bacterium. Comparing with the raw and the purified MWCNTs (r-MWCNTs and p-MWCNTs), which have been reported to possess antibacterial activity towards E. coli, ZnO/MWCNTs exhibited stronger antibacterial ability. The deposited ZnO was suggested to play an important role in the bactericidal action of ZnO/MWCNTs, while, the r-MWCNTs and p-MWCNTs served as more like adsorbing materials for E. coli. - Highlights: ► ZnO/MWCNTs were prepared and characterized. ► ZnO/MWCNTs were evaluated for the application potential as disinfection material. ► ZnO/MWCNTs exhibited strong antibacterial ability towards E. coli. ► ZnO seems to play an important role in the bactericidal action of ZnO/MWCNTs. ► MWCNTs served as more like adsorbing materials for E. coli.

  18. Green synthesis of halloysite nanotubes supported Ag nanoparticles for photocatalytic decomposition of methylene blue

    International Nuclear Information System (INIS)

    Zou Meiling; Zhu Han; Xu Congsheng; Du Mingliang; Fu Yaqin

    2012-01-01

    Using tea polyphenols (TPs) as a reductant, Ag nanoparticles (AgNPs) supported on halloysite nanotubes (HNTs) were simply and greenly synthesized for the photocatalytic decomposition of methylene blue (MB). HNTs were initially functionalized by N-β-aminoethyl-γ-aminopropyl trimethoxysilane (AEAPTMS) to introduce amino groups to form N-HNTs to fasten the AgNPs; then AgNPs were synthesized and ‘anchored’ on the surface of the HNTs. Fourier transform infrared spectroscopy was employed to testify the amino groups on the surface of the HNTs. Transmission electron microscopy, field-emission scanning electron microscopy and x-ray diffraction were utilized to characterize the structure and morphology of the synthesized HNTs supported by the AgNPs (AgNPs-N-HNTs). The results showed that the AgNPs had been synthesized and ‘anchored’ onto the surface of the HNTs with a diameter of about 20-30 nm. X-ray photoelectron spectroscopy analysis revealed the chelating interaction between the AgNPs and N atoms together with the TP molecular. The photocatalytic activity of the as-prepared AgNPs-N-HNTs catalyst was evaluated by decomposition of MB; the results showed that the prepared catalyst exhibited excellent catalytic activity and high adsorption capability to MB. (paper)

  19. Selective synthesis of double helices of carbon nanotube bundles grown on treated metallic substrates

    Energy Technology Data Exchange (ETDEWEB)

    Cervantes-Sodi, Felipe; Iniguez-Rabago, Agustin; Rosas-Melendez, Samuel; Ballesteros-Villarreal, Monica [Departamento de Fisica y Matematicas, Universidad Iberoamericana, Prolongacion Paseo de la Reforma 880, Lomas de Santa Fe (Mexico); Vilatela, Juan J. [IMDEA Materials Institute, E.T.S. de Ingenieros de Caminos, Madrid (Spain); Reyes-Gutierrez, Lucio G.; Jimenez-Rodriguez, Jose A. [Ingenieria Industrial, Grupo JUMEX, Ecatepec de Morelos, Estado de Mexico (Mexico); Palacios, Eduardo [Lab. de Microscopia Electronica de Ultra Alta Resolucion, Instituto Mexicano del Petroleo, San Bartolo Atepehuacan (Mexico); Terrones, Mauricio [Department of Physics, Department of Materials Science and Engineering and Materials Research Institute, Pennsylvania State University, University Park, PA (United States); Research Center for Exotic Nanocarbons (JST), Shinshu University, Nagano (Japan)

    2012-12-15

    Double-helix microstructures consisting of two parallel strands of hundreds of multi-walled carbon nanotubes (MWCNTs) have been synthesized by chemical vapour deposition of ferrocene/toluene vapours on metal substrates. Growth of coiled carbon nanostructures with site selectivity is achieved by varying the duration of thermochemical pretreatment to deposit a layer of SiO{sub x} on the metallic substrate. Production of multibranched structures of MWCNTs converging in SiO{sub x} microstructure is also reported. In the abstract figure, panel (a) shows a coloured micrograph of a typical double-helix coiled microstructure of MWCNTs grown on SiO{sub x} covered steel substrate. Green and blue show each of the two individual strands of MWCNTs. Panel (b) is an amplification of a SiO{sub x} microparticle (white) on the tip of the double-stranded coil (green and blue). The microparticle guides the collective growth of hundreds of MWCNTs to form the coiled structure. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  20. 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.

  1. Synthesis of Fe nanoparticles on polyaniline covered carbon nanotubes for oxygen reduction reaction

    Science.gov (United States)

    Hu, Tian-Hang; Yin, Zhong-Shu; Guo, Jian-Wei; Wang, Cheng

    2014-12-01

    Fe nanoparticles immobilized on polyaniline-covered carbon nanotube (CNT) surfaces (Fe NPs-PANI/CNT) are prepared by reducing FeCl3 in the mixing solution of aniline and CNT. Significantly, the structure of such composites can be effectively optimized by pretreating FeCl3 with sodium citrate (CA). In the absence of CNTs, we found these two routes have large differences in reduction behaviors and different PANI states with varied conductivities. Therefore, the self-assembly mechanism in the preparation is proposed and the controlled self-assembly manner in the pretreating route is disclosed. Under acid condition, both catalysts demonstrate high oxygen reduction reaction (ORR) activity with four-electron pathway, and high electrochemical durability, revealing a promising application in the proton exchange membrane fuel cells. However, the high Tafel slopes relating to the surface red-ox couple and porous conductivity are still the main obstacles to improve their ORR dynamic, and more efforts on these aspects are needed to drive non-noble catalyst application in future.

  2. Synthesis and Properties of Carbon Nanotube-Grafted Silica Nanoarchitecture-Reinforced Poly(Lactic Acid

    Directory of Open Access Journals (Sweden)

    Yao-Wen Hsu

    2017-07-01

    Full Text Available A novel nanoarchitecture-reinforced poly(lactic acid (PLA nanocomposite was prepared using multi-walled carbon nanotube (MWCNT-grafted silica nanohybrids as reinforcements. MWCNT-grafted silica nanohybrids were synthesized by the generation of silica nanoparticles on the MWCNT surface through the sol-gel technique. This synthetic method involves organo-modified MWCNTs that are dispersed in tetrahydrofuran, which incorporates tetraethoxysilane that undergoes an ultrasonic sol-gel process. Gelation yielded highly dispersed silica on the organo-modified MWCNTs. The structure and properties of the nanohybrids were established using 29Si nuclear magnetic resonance, Raman spectroscopy, wide-angle X-ray diffraction, thermogravimetric analysis, and transmission electron microscopy. The resulting MWCNT nanoarchitectures were covalently assembled into silica nanoparticles, which exhibited specific and controllable morphologies and were used to reinforce biodegradable PLA. The tensile strength and the heat deflection temperature (HDT of the PLA/MWCNT-grafted silica nanocomposites increased when the MWCNT-grafted silica was applied to the PLA matrix; by contrast, the surface resistivity of the PLA/MWCNT-grafted silica nanocomposites appeared to decline as the amount of MWCNT-grafted silica in the PLA matrix increased. Overall, the reinforcement of PLA using MWCNT-grafted silica nanoarchitectures was efficient and improved its mechanical properties, heat resistance, and electrical resistivity.

  3. Controllable synthesis of organic-inorganic hybrid MoOx/polyaniline nanowires and nanotubes.

    Science.gov (United States)

    Wang, Sinong; Gao, Qingsheng; Zhang, Yahong; Gao, Jing; Sun, Xuhui; Tang, Yi

    2011-02-01

    A novel chemical oxidative polymerization approach has been proposed for the controllable preparation of organic-inorganic hybrid MoO(x)/polyaniline (PANI) nanocomposites based on the nanowire precursor of Mo(3)O(10)(C(6)H(8)N)(2)·2H(2)O with sub-nanometer periodic structures. The nanotubes, nanowires, and rambutan-like nanoparticles of MoO(x)/PANI were successfully obtained through simply modulating the pH values to 2.5-3.5, ≈2.0 and ≈1.0, respectively. Through systematic physicochemical characterization, such as scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, and so forth, the composition and structure of MoO(x)/PANI hybrid nanocomposites are well confirmed. It is found that the nanowire morphology of the precursor is the key to achieve the one-dimensional (1D) structures of final products. A new polymerization-dissolution mechanism is proposed to explain the formation of such products with different morphologies, in which the match between polymerization and dissolution processes of the precursor plays the important role. This approach will find a new way to controllably prepare various organic-inorganic hybrid 1D nanomaterials especially for polymer-hybrid nanostructures. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Synthesis and Characterization of Hexahapto-Chromium Complexes of Single-Walled Carbon Nanotubes

    KAUST Repository

    Kalinina, Irina

    2016-12-17

    This chapter employs purified pristine single-walled carbon nanotubes (SWNTs) and octadecylaminefunctionalized-SWNTs. These SWNTs are employed for investigate the potential of the SWNT sidewall to function as a hexahapto ligand for chromium (Cr), with in-depth characterization of the products using some of the techniques, such as thermogravimetric analysis (TGA), transmission electron microscopy (TEM), x-ray photoelectron spectroscopy (XPS). Purified electric arc (EA)-produced SWNTs (P2-SWNT) and octadecylaminefunctionalized SWNTs were obtained from Carbon Solutions, Inc. The TEM images show the removal of the Cr particles from the outer surface of the SWNT bundles in the SWNT-Cr complexes after decomplexation; Cr attachment to the surface of the as-prepared complexes (η6-SWNT)Cr(CO)3 and (η6-SWNT-CONH(CH2)17CH3)Cr(CO)3 is clearly evident. The positions of the bands in the Raman spectra of SWNTs are sensitive to doping and thus the chapter examines the effect of complexation of the Cr(CO)3 and Cr(η6-benzene) units on the position of the G and 2D bands in the (η6-SWNT)Cr(CO)3 and (η6-SWNT)Cr(η6-benzene) complexes.

  5. Synthesis and properties of platinum on multiwall carbon nanotube modified by chitosan

    Science.gov (United States)

    Fikriyyah, A. K.; Chaldun, E. R.; Indriyati

    2018-03-01

    Platinum nanoparticles on multiwall carbon nanotubes (Pt/MWCNT) play an important role in fuel cell to convert the chemical energy from a fuel into electricity. In this study, Pt/MWCNT electrocatalysts were prepared by chemical reduction of the metal salts in chitosan as the support. Firstly, commercial MWCNTs were functionalized by oxidative process using a mixture of nitric acid and sulfuric acid. Then, functionalized MWCNTs were mixed with chitosan-acetic acid solution to conduct grafting reaction with NH2 groups in chitosan by solution polymerization method. Platinum nanoparticles were loaded onto the surface of the MWCNTs after hexachloroplatinic acid was reduced by sodium hydroxide solution. The result showed that Pt was attached on MWCNT based on analysis from EDS, XRD, and UV Vis Spectroscopy. UV Vis analysis indicates the plasmon absorbance band of Pt nanoparticles in Pt/MWCNT, while XRD analysis confirmed the size of Pt particle in nanometer. This elucidates the potential procedure to synthesize Pt/MWCNT using chitosan.

  6. Ferric oxide nanoparticles decorated carbon nanotubes and carbon nanofibers: From synthesis to enhanced removal of phenol

    Directory of Open Access Journals (Sweden)

    Hamza A. Asmaly

    2015-09-01

    Full Text Available In this work, ferric oxide nanoparticle decorated carbon fibers and carbon nanotubes (CNF/Fe2O3 and CNT/Fe2O3 were synthesized and characterized by scanning electron microscopy (SEM, thermogravimetric analysis (TGA, energy dispersive X-ray spectroscopy (EDS, transmission electron microscopy (TEM, X-ray diffraction (XRD, zeta potential and BET surface area analyzer. The prepared nanocomposites were evaluated or the removal of phenol ions from aqueous solution. The effects of experimental parameters, such as shaking speed, pH, contact time, adsorbent dosage and initial concentration, were evaluated for the phenol removal efficiency. The adsorption experimental data were represented by both the Langmuir and Freundlich isotherm models. The Langmuir isotherm model best fitted the data on the adsorption of phenol, with a high correlation coefficient. The adsorption capacities, as determined by the Langmuir isotherm model were 0.842, 1.098, 1.684 and 2.778 mg/g for raw CNFs, raw CNTs, CNF–Fe2O3 and CNT–Fe2O3, respectively.

  7. Synthesis and characterisation of epoxy resins reinforced with carbon nanotubes and nanofibers.

    Science.gov (United States)

    Prolongo, S G; Gude, M R; Ureña, A

    2009-10-01

    Epoxy nanocomposites were fabricated using two kinds of nanofiller, amino-functionalized multi-walled carbon nanotubes (CNTs) and non-treated long carbon nanofibers (CNFs). The non-cured mixtures were analysed through viscosity measurements. The effect of the nanoreinforcement on the curing process was determined by differential scanning calorimetry. Finally, the characterisation of cured nanocomposites was carried out studying their thermo-mechanical and electrical behaviour. At room temperature, the addition of CNTs causes a viscosity increase of epoxy monomer much more marked than the introduction of CNFs due to their higher specific area. It was probed that in that case exists chemical reaction between amino-functionalized CNTs and the oxirane rings of epoxy monomer. The presence of nanoreinforcement induces a decrease of curing reaction rate and modifies the epoxy conversion reached. The glass transition temperature of the nanocomposites decreases with the contents of CNTs and CNFs added, which could be related to plasticization phenomena of the nanoreinforcements. The storage modulus of epoxy resin significantly increases with the addition of CNTs and CNFs. This augment is higher with amino-functionalized CNTs due, between other reasons, to the stronger interaction with the epoxy matrix. The electrical conductivity is greatly increased with the addition of CNTs and CNFs. In fact, the percolation threshold is lower than 0.25 wt% due to the high aspect ratio of the used nanoreinforcements.

  8. Controllable synthesis of single-walled carbon nanotube framework membranes and capsules.

    Science.gov (United States)

    Song, Changsik; Kwon, Taeyun; Han, Jae-Hee; Shandell, Mia; Strano, Michael S

    2009-12-01

    Controlling the morphology of membrane components at the nanometer scale is central to many next-generation technologies in water purification, gas separation, fuel cell, and nanofiltration applications. Toward this end, we report the covalent assembly of single-walled carbon nanotubes (SWNTs) into three-dimensional framework materials with intertube pores controllable by adjusting the size of organic linker molecules. The frameworks are fashioned into multilayer membranes possessing linker spacings from 1.7 to 3.0 nm, and the resulting framework films were characterized, including transport properties. Nanoindentation measurements by atomic force microscopy show that the spring constant of the SWNT framework film (22.6 +/- 1.2 N/m) increased by a factor of 2 from the control value (10.4 +/- 0.1 N/m). The flux ratio comparison in a membrane-permeation experiment showed that larger spacer sizes resulted in larger pore structures. This synthetic method was equally efficient on silica microspheres, which could then be etched to create all-SWNT framework, hollow capsules approximately 5 mum in diameter. These hollow capsules are permeable to organic and inorganic reagents, allowing one to form inorganic nanoparticles, for example, that become entrapped within the capsule. The ability to encapsulate functional nanomaterials inside perm-selective SWNT cages and membranes may find applications in new adsorbents, novel catalysts, and drug delivery vehicles.

  9. Synthesis of carbon nanotubes and porous carbons from printed circuit board waste pyrolysis oil

    International Nuclear Information System (INIS)

    Quan Cui; Li Aimin; Gao Ningbo

    2010-01-01

    The possibility and feasibility of using pyrolysis oil from printed circuit board (PCB) waste as a precursor for advanced carbonaceous materials is presented. The PCB waste was first pyrolyzed in a laboratory scale fixed bed reactor at 600 deg. C to prepare pyrolysis oil. The analysis of pyrolysis oil by gas chromatography-mass spectroscopy indicated that it contained a very high proportion of phenol and phenol derivatives. It was then polymerized in formaldehyde solution to synthesize pyrolysis oil-based resin which was used as a precursor to prepare carbon nanotubes (CNTs) and porous carbons. Scanning electron microscopy and transmission microscopy investigation showed that the resulting CNTs had hollow cores with outer diameter of ∼338 nm and wall thickness of ∼86 nm and most of them were filled with metal nanoparticles or nanorods. X-ray diffraction reveals that CNTs have an amorphous structure. Nitrogen adsorption isotherm analysis indicated the prepared porous carbons had a Brunauer-Emmett-Teller surface area of 1214 m 2 /g. The mechanism of the formation of the CNTs and porous carbons was discussed.

  10. Free fall plasma-arc reactor for synthesis of carbon nanotubes in microgravity

    International Nuclear Information System (INIS)

    Alford, J. M.; Mason, G. R.; Feikema, D. A.

    2006-01-01

    High temperatures inside the plasma of a carbon arc generate strong buoyancy driven convection which has an effect on the growth and morphology of the single-walled carbon nanotubes (SWNTs). To study the effect of buoyancy on the arc process, a miniature carbon arc apparatus was designed and developed to synthesize SWNTs in a microgravity environment substantially free from buoyant convective flows. An arc reactor was operated in the 2.2 and 5.18 s drop towers at the NASA Glenn Research Center. The apparatus employed a 4 mm diameter anode and was powered by a portable battery pack capable of providing in excess of 300 A at 30 V to the arc for the duration of a 5 s drop. However, the principal result is that no dramatic difference in sample yield or composition was noted between normal gravity and 2.2 and 5 s long microgravity runs. Much longer duration microgravity time is required for SWNT's growth such as the zero-G aircraft, but more likely will need to be performed on the international space station or an orbiting spacecraft

  11. Effects of axial magnetic field on the electronic and optical properties of boron nitride nanotube

    Science.gov (United States)

    Chegel, Raad; Behzad, Somayeh

    2011-07-01

    The splitting of band structure and absorption spectrum, for boron nitride nanotubes (BNNTs) under axial magnetic field, is studied using the tight binding approximation. It is found that the band splitting ( ΔE) at the Γ point is linearly proportional to the magnetic field ( Φ/Φ0). Our results indicate that the splitting rate νii, of the two first bands nearest to the Fermi level, is a linear function of n -2 for all (n,0) zigzag BNNTs. By investigation of the dependence of band structure and absorption spectrum to the magnetic field, we found that absorption splitting is equal to band splitting and the splitting rate of band structure can be used to determine the splitting rate of the absorption spectrum.

  12. Developing polymer composite materials: carbon nanotubes or graphene?

    Science.gov (United States)

    Sun, Xuemei; Sun, Hao; Li, Houpu; Peng, Huisheng

    2013-10-04

    The formation of composite materials represents an efficient route to improve the performances of polymers and expand their application scopes. Due to the unique structure and remarkable mechanical, electrical, thermal, optical and catalytic properties, carbon nanotube and graphene have been mostly studied as a second phase to produce high performance polymer composites. Although carbon nanotube and graphene share some advantages in both structure and property, they are also different in many aspects including synthesis of composite material, control in composite structure and interaction with polymer molecule. The resulting composite materials are distinguished in property to meet different applications. This review article mainly describes the preparation, structure, property and application of the two families of composite materials with an emphasis on the difference between them. Some general and effective strategies are summarized for the development of polymer composite materials based on carbon nanotube and graphene. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. 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.

  14. Synthesis and Characterization of Hierarchical Structured TiO2 Nanotubes and Their Photocatalytic Performance on Methyl Orange

    Directory of Open Access Journals (Sweden)

    Kai Liu

    2015-01-01

    Full Text Available Hierarchical structured TiO2 nanotubes were prepared by mechanical ball milling of highly ordered TiO2 nanotube arrays grown by electrochemical anodization of titanium foil. Scanning electron microscopy, transmission electron microscopy, X-ray diffraction, specific surface area analysis, UV-visible absorption spectroscopy, photocurrent measurement, photoluminescence spectra, electrochemical impedance spectra, and photocatalytic degradation test were applied to characterize the nanocomposites. Surface area increased as the milling time extended. After 5 h ball milling, TiO2 hierarchical nanotubes exhibited a corn-like shape and exhibited enhanced photoelectrochemical activity in comparison to commercial P25. The superior photocatalytic activity is suggested to be due to the combined advantages of high surface area of nanoparticles and rapid electron transfer as well as collection of the nanotubes in the hierarchical structure. The hierarchical structured TiO2 nanotubes could be applied into flexible applications on solar cells, sensors, and other photoelectrochemical devices.

  15. Effects of single-walled carbon nanotubes on the optical and photo-conductive properties of their composite films with regio-regular poly(3-hexylthiophene)

    International Nuclear Information System (INIS)

    Bakour, Anass; Geschier, Frédéric; Baitoul, Mimouna; Mbarek, Mohamed; El-Hadj, Karim; Duvail, Jean-Luc; Lefrant, Serge; Faulques, Eric; Massuyeau, Florian; Wery-Venturini, Jany

    2014-01-01

    The effect of a small admixture of single-walled carbon nanotubes (SWNTs) HiPCO (high pressure carbon monoxide) (from 0.5 to 2 wt%) on the supramolecular structure in regio-regular poly(3-hexylthiophene) (RR-P3HT) thin films is studied and their optical and photoconductivity properties are investigated. It is demonstrated that the presence of such small amounts of nanotubes improves the structural organization in the films as evidenced by X-ray diffraction (XRD) studies. This is confirmed by UV–visible optical absorption investigations which clearly show a better conjugation of P3HT in the presence of nanotubes. In Raman spectra of composites, changes in intensities and frequencies of the radial breathing modes are observed upon addition of nanotubes. This can be rationalized by a modification of the resonance conditions caused by a selective dispersion and wrapping of SWNTs via π-interaction (π-stacking). As a consequence of these interactions, a dramatic photoluminescence (PL) quenching is observed which becomes more and more pronounced with increasing the nanotube content. This implies a fast photo-induced electron transfer favoured by a large area of the SWNTs/P3HT interface and strong interactions between these two components. An increase in the composite photocurrent by at least one-order of magnitude, as compared to the case of pure P3HT film, is the most pronounced effect of this electron transfer. These two effects are of crucial importance for the application of the investigated composites in bulk hetero-junction photovoltaic cells (BHJPCs) and organic photo-detectors (OPDs). - Highlights: • Optical properties of single-walled carbon nanotubes/P3HT films are investigated. • The insertion of SWNTs leads to an improvement of structural organization. • Composite films shows photoluminescence quenching at low SWNTs concentration. • Existence of a fast photo-induced electron transfer between SWNTs and P3HT. • These two effects are of crucial

  16. Effects of single-walled carbon nanotubes on the optical and photo-conductive properties of their composite films with regio-regular poly(3-hexylthiophene)

    Energy Technology Data Exchange (ETDEWEB)

    Bakour, Anass [University Sidi Mohammed Ben Abdellah, Faculty of Sciences, Dhar El Mahraz, Laboratory of Solid State Physics, Group Polymers and Nanomaterials, PO Box 1796, Atlas, Fes 30000 (Morocco); Geschier, Frédéric [Institut des Matériaux Jean Rouxel, Université de Nantes, CNRS, UMR 6502, 2 rue de la Houssinière, PO Box 3229, 44322 Nantes cedex (France); Baitoul, Mimouna, E-mail: baitoul@yahoo.fr [University Sidi Mohammed Ben Abdellah, Faculty of Sciences, Dhar El Mahraz, Laboratory of Solid State Physics, Group Polymers and Nanomaterials, PO Box 1796, Atlas, Fes 30000 (Morocco); Mbarek, Mohamed [Institut des Matériaux Jean Rouxel, Université de Nantes, CNRS, UMR 6502, 2 rue de la Houssinière, PO Box 3229, 44322 Nantes cedex (France); Unité de Recherche, Matériaux Nouveaux et Dispositifs Electroniques Organiques, Faculté des Sciences, Université de Monastir, 5000 Monastir (Tunisia); El-Hadj, Karim; Duvail, Jean-Luc; Lefrant, Serge; Faulques, Eric; Massuyeau, Florian; Wery-Venturini, Jany [Institut des Matériaux Jean Rouxel, Université de Nantes, CNRS, UMR 6502, 2 rue de la Houssinière, PO Box 3229, 44322 Nantes cedex (France)

    2014-02-14

    The effect of a small admixture of single-walled carbon nanotubes (SWNTs) HiPCO (high pressure carbon monoxide) (from 0.5 to 2 wt%) on the supramolecular structure in regio-regular poly(3-hexylthiophene) (RR-P3HT) thin films is studied and their optical and photoconductivity properties are investigated. It is demonstrated that the presence of such small amounts of nanotubes improves the structural organization in the films as evidenced by X-ray diffraction (XRD) studies. This is confirmed by UV–visible optical absorption investigations which clearly show a better conjugation of P3HT in the presence of nanotubes. In Raman spectra of composites, changes in intensities and frequencies of the radial breathing modes are observed upon addition of nanotubes. This can be rationalized by a modification of the resonance conditions caused by a selective dispersion and wrapping of SWNTs via π-interaction (π-stacking). As a consequence of these interactions, a dramatic photoluminescence (PL) quenching is observed which becomes more and more pronounced with increasing the nanotube content. This implies a fast photo-induced electron transfer favoured by a large area of the SWNTs/P3HT interface and strong interactions between these two components. An increase in the composite photocurrent by at least one-order of magnitude, as compared to the case of pure P3HT film, is the most pronounced effect of this electron transfer. These two effects are of crucial importance for the application of the investigated composites in bulk hetero-junction photovoltaic cells (BHJPCs) and organic photo-detectors (OPDs). - Highlights: • Optical properties of single-walled carbon nanotubes/P3HT films are investigated. • The insertion of SWNTs leads to an improvement of structural organization. • Composite films shows photoluminescence quenching at low SWNTs concentration. • Existence of a fast photo-induced electron transfer between SWNTs and P3HT. • These two effects are of crucial

  17. Rebar graphene from functionalized boron nitride nanotubes.

    Science.gov (United States)

    Li, Yilun; Peng, Zhiwei; Larios, Eduardo; Wang, Gunuk; Lin, Jian; Yan, Zheng; Ruiz-Zepeda, Francisco; José-Yacamán, Miguel; Tour, James M

    2015-01-27

    The synthesis of rebar graphene on Cu substrates is described using functionalized boron nitride nanotubes (BNNTs) that were annealed or subjected to chemical vapor deposition (CVD) growth of graphene. Characterization shows that the BNNTs partially unzip and form a reinforcing bar (rebar) network within the graphene layer that enhances the mechanical strength through covalent bonds. The rebar graphene is transferrable to other substrates without polymer assistance. The optical transmittance and conductivity of the hybrid rebar graphene film was tested, and a field effect transistor was fabricated to explore its electrical properties. This method of synthesizing 2D hybrid graphene/BN structures should enable the hybridization of various 1D nanotube and 2D layered structures with enhanced mechanical properties.

  18. Scalable synthesis of hierarchically structured carbon nanotube-graphene fibres for capacitive energy storage

    Science.gov (United States)

    Yu, Dingshan; Goh, Kunli; Wang, Hong; Wei, Li; Jiang, Wenchao; Zhang, Qiang; Dai, Liming; Chen, Yuan

    2014-07-01

    Micro-supercapacitors are promising energy storage devices that can complement or even replace batteries in miniaturized portable electronics and microelectromechanical systems. Their main limitation, however, is the low volumetric energy density when compared with batteries. Here, we describe a hierarchically structured carbon microfibre made of an interconnected network of aligned single-walled carbon nanotubes with interposed nitrogen-doped reduced graphene oxide sheets. The nanomaterials form mesoporous structures of large specific surface area (396 m2 g-1) and high electrical conductivity (102 S cm-1). We develop a scalable method to continuously produce the fibres using a silica capillary column functioning as a hydrothermal microreactor. The resultant fibres show a specific volumetric capacity as high as 305 F cm-3 in sulphuric acid (measured at 73.5 mA cm-3 in a three-electrode cell) or 300 F cm-3 in polyvinyl alcohol (PVA)/H3PO4 electrolyte (measured at 26.7 mA cm-3 in a two-electrode cell). A full micro-supercapacitor with PVA/H3PO4 gel electrolyte, free from binder, current collector and separator, has a volumetric energy density of ~6.3 mWh cm-3 (a value comparable to that of 4 V-500 µAh thin-film lithium batteries) while maintaining a power density more than two orders of magnitude higher than that of batteries, as well as a long cycle life. To demonstrate that our fibre-based, all-solid-state micro-supercapacitors can be easily integrated into miniaturized flexible devices, we use them to power an ultraviolet photodetector and a light-emitting diode.

  19. Synthesis and characterization of poly lactic acid and multiwall carbon nano-tubes mixtures

    Science.gov (United States)

    Kumar LG, Santhosh; del A. Cardona, Rocío; Berríos-Soto, Melvin; Santiago-Avilés, Jorge J.

    2011-10-01

    The motivation for this study is to reproduce processing conditions which lead to the formation of photo or photoinduced thermal actuation, combined with inexpensive, environmentally friendly (easily degradable) materials. Commercially available polymer, poly lactic acid (PLA), was used in our studies. PLA is a well know biodegradable polymer naturally obtained from corn. PLA was received as a solid resin in pellet form and dissolved in 1:3 acetone/chloroform solutions, to achieve the proper electrospinning kinematic viscosity. Once in the liquid phase, the material was mixed with commercially available multi-walled carbon nanotubes (MWCNTs) at varying concentrations and dispersed by severe sonication. The mixtures was electrospun at room temperature using a home built electrospinning apparatus capable of depositing randomly oriented fiber mats or oriented fibers onto different substrates, ranging from oxidized silicon wafers, alumina squares or glass microscope slides. The fibers diameters and lengths are statistically distributed following a log-normal distribution and the mean and dispersion are controlled by spinning parameters. Once the fibers were electrospun, they were compositionally, morphologically and structurally characterized by thermal and gravimetric analysis (TGA/DTA), rheology, imaging using a focused Ion Beam Scanning Electron Microscope (IBSEM), and IR /Raman methodologies. These studies can be used to explore PLA-MWCNTs mixtures suitability in applications such as super-capacitor technology, which would enable us to pursue further research in this field, while focusing on improving the electro spinning conditions so as to be able to better anticipate fiber morphology to generate a consistent regime of fibers.

  20. Synthesis of hydroxyapatite/multi-walled carbon nanotubes for the removal of fluoride ions from solution

    Science.gov (United States)

    Ruan, Zhongyuan; Tian, Yaxi; Ruan, Jifu; Cui, Guijia; Iqbal, Kanwal; Iqbal, Anam; Ye, Herui; Yang, Zhangzhong; Yan, Shiqiang

    2017-08-01

    A novel composite material, hydroxyapatite (HA)-multi-walled carbon nanotubes (MWCNTs), was prepared using a simple in-situ sol-gel method, and was used for the first time to remove fluoride from water. The novel HA-MWCNTs were characterized using TEM, FT-IR, BET and XRD analysis. The TEM and SAED results revealed that the MWCNTs were uniformly encapsulated by hydroxyapatite nanoparticles. The synthesized HA-MWCNTs had a high specific surface area (180.504 m2 g-1), with an average pore width (14.607 nm) and pore volume (0.774 cm3 g-1), which produced a defluoridation capacity (DC) of 30.22 mgF- g-1. This value was greater than unmodified hydroxyapatite (HA), which exhibited a larger specific surface area (172.233 m2 g-1) and an excellent DC of 17.80 mgF- g-1. A number of pertinent parameters that could affect the defluoridation performance of the HA/MWCNTs including weight ratios of the two key materials, solution pH and competing anions were carefully and comprehensively examined. It was found that the adsorption results followed the Langmuir and Freundlich isotherm model, and the sorption kinetics of the F- appeared to exhibit a pseudo second order. Moreover, the adsorption reaction was spontaneous and endothermic and appeared to exhibit a higher initial adsorption rate. This reaction appeared to occur result from both anion exchange and electrostatic interactions. When the HA-MWCNTs (MH6) were at an adsorbent dose of 2.0 g L-1, they were able to decrease the fluoride concentration of actual nuclear industry wastewater from 8.79 mg L-1 to about 0.25 mg L-1 (97.15% removal efficiency). The experimental results of this study showed that the HA-MWCNTs composites have application potential for the removal of fluoride ions from wastewater.

  1. Synthesis and wear behavior of aluminum 6061 alloy reinforced with carbon nanotubes

    Science.gov (United States)

    Khalil, Abdullah

    In the present work, Al6061 alloy was uniformly reinforced with 0.5, 0.75, 1 and 2 wt. % Carbon Nanotubes (CNTs) using two way dispersion method. For consolidation, Spark Plasma Sintering (SPS) was used which resulted in very high densification for the matrix as well as composite. Results showed that addition of CNTs lead to increased hardness of the material and maximum hardness was found for 1 wt. % CNTs. So this composition was selected for detailed wear analysis. Pin-on-disk wear tests were conducted for the monolithic Al6061 and the composite at a constant speed of 0.5 m/s with varying load from 5 N to 30 N under dry sliding conditions using AISI 4140 steel disk as a counterface. The composite displayed lower wear rate and friction coefficient at lower levels of applied stress (0.175 to 0.525 MPa). Under higher stresses (0.700 to 1.050 MPa), the increased brittleness and porosity of the composite caused severe fracturing and delamination resulting in excessive wear rate and friction coefficient for the composite as compared to monolithic Al6061. The transition from mild to severe wear regime in composite occurred also at lower stress as compared to monolith. Analysis of the worn surfaces revealed abrasion as the dominant wear mechanism for both the materials at lower stresses. At higher stress levels, adhesion was found to be dominant in monolithic Al6061 whereas in composite, excessive sub-surface fracturing and delamination was mainly observed.

  2. Synthesis and characterization of carbon nanotubes on clay minerals and its application to a hydrogen peroxide biosensor

    International Nuclear Information System (INIS)

    Hsu, H.-L.; Jehng, J.-M.

    2009-01-01

    In this study, we demonstrate the synthesis of carbon nanotubes (CNTs) on clay minerals, and the development of biosensors based on Nafion-CNT/Clay-Au and Nafion-CNT/Clay-Au-Glucose oxidase (GOD) composite films for the detection of hydrogen peroxide (H 2 O 2 ) and glucose, respectively. The CNTs are synthesized on nickel cation exchanged clay mineral platelets. From field-emission scanning electron microscope images, X-ray diffraction, Fourier transfer infrared and thermogravimetric analysis results, the clay layers are exfoliated and delaminated after the growth of CNTs on them. The mixed hybrid film of Nafion, CNT/Clay, Au particles and GOD is coated on the glassy carbon (GC) electrode to detect H 2 O 2 or glucose. This film exhibits a detection limit of 5.0 x 10 -5 M for H 2 O 2 with a sensitivity of 280 nA mM -1 . In addition, the amperometric response for glucose containing 2.0 mg mL -1 GOD in the Nafion-CNT/Clay-Au-GOD modified GC electrode exhibits a sensitivity of 620 nA mM -1 with a linear range up to 1850 μM. A higher sensitivity and shorter response time are observed with increasing GOD content in the composite matrix film. Besides, the highest sensitivity of 2032 nA mM -1 is obtained with the addition of the 10.0 mg mL -1 GOD in the composite film. Consequently, the CNT/Clay/Nafion medium can probably be a useful electrode for the development of sensors due to its high sensitivity and applicability

  3. Effect of nitrogen doping on the microstructure and visible light photocatalysis of titanate nanotubes by a facile cohydrothermal synthesis via urea treatment

    International Nuclear Information System (INIS)

    Hu, Cheng-Ching; Hsu, Tzu-Chien; Lu, Shan-Yu

    2013-01-01

    A facile one-step cohydrothermal synthesis via urea treatment has been adopted to prepare a series of nitrogen-doped titanate nanotubes with highly efficient visible light photocatalysis of rhodamine B, in an effect to identify the effect of nitrogen doping on the photodegradation efficiency. The morphology and microstructure of the thus-prepared N-doped titanates were characterized by nitrogen adsorption/desorption isotherms, transmission electron microscopy, and scanning electron microscopy. With increasing urea loadings, the N-doped titanates change from a porous multi-layer and nanotube-shaped to a dense and aggregated particle-shaped structure, accompanied with reduced specific surface area and pore volume and enhanced pore diameter. Interstitial linkage to titanate via Ti-O-N and Ti-N-O is confirmed by X-ray photoelectron spectroscopy. Factors governing the photocatalytic degradation such as the specific surface area of the catalyst and the degradation pathway are analyzed, a mechanistic illustration on the photodegradation is provided, and a 3-stage degradation mechanism is identified. The synergistic contribution due to the enhanced deethylation and chromophore cleavage on rhodamine B molecules and the reduced band gap on the catalyst TiO 2 by interstitial nitrogen-doping has been accounted for the high photodegradation efficiency of the N-doped titanate nanotubes.

  4. Synthesis of free-standing carbon nanohybrid by directly growing carbon nanotubes on air-sprayed graphene oxide paper and its application in supercapacitor

    International Nuclear Information System (INIS)

    Wei, Li; Jiang, Wenchao; Yuan, Yang; Goh, Kunli; Yu, Dingshan; Wang, Liang; Chen, Yuan

    2015-01-01

    We report the synthesis of a free-standing two dimensional carbon nanotube (CNT)-reduced graphene oxide (rGO) hybrid by directly growing CNTs on air-sprayed GO paper. As a result of the good integration between CNTs and thermally reduced GO film during chemical vapor deposition, excellent electrical conductivity (2.6×10 4 S/m), mechanical flexibility (electrical resistance only increases 1.1% after bent to 90° for 500 times) and a relatively large surface area (335.3 m 2 /g) are achieved. Two-electrode supercapacitor assembled using the CNT–rGO hybrids in ionic liquid electrolyte (1-ethyl-3-methylimidazolium tetrafluoroborate) shows excellent stability upon 500 bending cycles with the gravimetric energy density measuring 23.7 Wh/kg and a power density of 2.0 kW/kg. Furthermore, it shows an impedance phase angle of −64.4° at a frequency of 120 Hz, suggesting good potentials for 120 Hz alternating current line filtering applications. - Graphical abstract: Flexible and highly conductive carbon nanotube-reduced graphene oxide nanohybrid. - Highlights: • Direct growth of carbon nanotubes by chemical vapor deposition on air-sprayed graphene oxide paper. • Two-dimensional carbon nanohybrid with excellent conductivity and mechanical flexibility. • Supercapacitor with excellent performance stability upon mechanical deformation for flexible electronics applications. • Supercapacitor with high impedance phase angle for 120 Hz alternating current line filtering applications

  5. A short designed semi-aromatic organic nanotubesynthesis, chiroptical characterization, and host properties

    DEFF Research Database (Denmark)

    Wixe, Torbjörn; Christensen, Niels Johan; Lidin, Sven

    2014-01-01

    to molecular dynamics simulations in chloroform). The synthesis of the tube, a heptamer, is based on a series of Friedländer condensations and the use of pyrido[3,2-d]pyrimidine units as masked 2-amino aldehydes, as a general means to propagate organic tubular structures and the introduction of a methoxy group...... for modification toward solubility and functionalization are described. The electronic CD spectra of the tube and molecular intermediates are correlated with theoretical spectra calculated with time-dependent density functional theory to characterize the chirality of the tube. Both experimental (NMR...

  6. Determination of the Absolute Enantiomeric Excess of the Carbon Nanotube Ensemble by Symmetry Breaking Using the Optical Titration Method.

    Science.gov (United States)

    Sim, Jinsook; Kim, Somin; Jang, Myungsu; Park, Minsuk; Oh, Hyunkyu; Ju, Sang-Yong

    2017-10-17

    Symmetry breaking of single-walled carbon nanotubes (SWNTs) has profound effects on their optoelectronic properties that are essential for fundamental study and applications. Here, we show that isomeric SWNTs that exhibit identical photoluminescence (PL) undergo symmetry breaking by flavin mononucleotide (FMN) and exhibit dual PLs and different binding affinities (K a ). Increasing the FMN concentration leads to systematic PL shifts of SWNTs according to structural modality and handedness due to symmetry breaking. Density gradient ultracentrifugation using a FMN-SWNT dispersion displays PL shifts and different densities according to SWNT handedness. Using the optical titration method to determine the PL-based K a of SWNTs against an achiral surfactant as a titrant, left- and right-handed SWNTs display two-step PL inflection corresponding to respective K a values with FMN, which leads to the determination of the enantiomeric excess (ee) of the SWNT ensemble that was confirmed by circular dichroism measurement. Decreasing the FMN concentration for the SWNT dispersion leads to enantiomeric selection of SWNTs. The titration-based ee determination of the widely used sodium cholate-based SWNT dispersion was also demonstrated by using FMN as a cosurfactant.

  7. Synthesis and characterization of titania nanotubes and gold nanoparticles nanocomposites for hydrogen production improvement

    Energy Technology Data Exchange (ETDEWEB)

    Galvao, Rhauane Almeida, E-mail: rhaugalvao@hotmail.com [Universidade Federal de Pernambuco (UFPE), Recife, PE(Brazil); Silva, Germana Michelle Medeiros e; Machado, Giovanna [Centro de Tecnologias Estrategicas do Nordeste, Recife, PE (Brazil)

    2016-07-01

    Full text: In the New Policies Scenario, world electricity demand increases by almost 80% over the period 2012-2040. According to this, the world will need to increase energy supply and cleanly-generated electricity. Besides renewable energy sources such as solar energy have a high cost, it can provide clean power. Because of this, it is of great interest to create new devices capable to absorb and convert solar into electrical energy. Titanium dioxide (TiO{sub 2}) is a great searched semiconductor for solar energy conversion because of its great stability and low cost, besides its low solar energy absorption (± 5% of solar spectrum). Sensitization with nanoparticles, such as gold (Au), is a good alternative to increase its efficiency. Using architectures such as nanotubes (NTs) and nanoparticles (NPs) is of interesting because of the unique properties achieved at these dimensions. To bind Au Nps into TiO{sub 2} NTs is a great challenge. Using self assembled thin films is a good option because of its operability. On this study, amorphous TiO{sub 2} NTs were synthesized by anodization of a Ti foil using an organic electrolyte with a set potential during 30 minutes. After this, the self-assembly method was used on the tubes using Poly(Allylamine Hydrochloride) (PAH) as polycation and Poly(Acrilic Acid) (PAA) as polyanion, completing 10 and 10.5. Then, the samples were immersed in a solution of Tetrachloroauric acid (HAuCl{sub 4}) at different pHs during 2 hours, lightly washed and submitted to UV-radiation during 24 hours. In order to make a comparison, it has been prepared samples without binds. At last, the samples were heat treated at 400°C during 3 hours to obtain TiO2 anatase phase. X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Diffuse Reflectance Spectroscopy characterized the samples. Finally, the hydrogen production was evaluated using a solar simulator and gas chromatography. The results show that the use of a bind is greatly favorable to

  8. Synthesis and optical spectroscopy of (hetero)-nanocrystals: An exciting interplay between Chemistry and Physics

    NARCIS (Netherlands)

    Groeneveld, E.

    2012-01-01

    This thesis describes the synthesis and study of the optical properties of various colloidal semiconductor (hetero)nanocrystals ((H)NCs). Before the experimental results are discussed in detail, the essential theoretical background on the chemical and physical aspects of this work is provided in

  9. 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.

  10. Optical properties of ordered vertical arrays of multi-walled carbon nanotubes from FDTD simulations.

    Science.gov (United States)

    Bao, Hua; Ruan, Xiulin; Fisher, Timothy S

    2010-03-15

    A finite-difference time-domain (FDTD) method is used to model thermal radiative properties of vertical arrays of multi-walled carbon nanotubes (MWCNT). Individual CNTs are treated as solid circular cylinders with an effective dielectric tensor. Consistent with experiments, the results confirm that CNT arrays are highly absorptive. Compared with the commonly used Maxwell-Garnett theory, the FDTD calculations generally predict larger reflectance and absorbance, and smaller transmittance, which are attributed to the diffraction and scattering within the cylinder array structure. The effects of volume fraction, tube length, tube distance, and incident angle on radiative properties are investigated systematically. Low volume fraction and long tubes are more favorable to achieve low reflectance and high absorbance. For a fixed volume fraction and finite tube length, larger periodicity results in larger reflectance and absorbance. The angular dependence studies reveal an optimum incident angle at which the reflectance can be minimized. The results also suggest that an even darker material could be achieved by using CNTs with good alignment on the top surface.

  11. Optical absorption of zigzag single walled boron nitride nanotubes in axial magnetic field

    Science.gov (United States)

    Chegel, Raad; Behzad, Somayeh

    2013-11-01

    We have investigated the effect of axial magnetic field on the band structure, dipole matrix elements and absorption spectrum in different energy ranges, using tight binding approximation. It is found that magnetic field breaks the degeneracy in the band structure and creates new allowed transitions in the dipole matrix which leads to creation of new peaks in the absorption spectrum. It is found that, unlike to CNTs which show metallic-semiconductor transition, the BNNTs remain semiconductor in any magnetic field strength. By calculation the diameter dependence of peak positions, we found that the positions of three first peaks in the lower energy region (E <5.3 eV) are proportional to n-2. In the middle energy region (7 < E < 7.5 eV) all (n, 0) zigzag BNNTs, with even and odd nanotube index, have two distinct peaks in the absence of magnetic field which these peaks may be used to identify zigzag BNNTs from other tube chiralities. For odd (even) tubes, in the middle energy region, applying the magnetic field leads to splitting of these two peaks into three (five) distinct peaks.

  12. Controlling Structural Characteristics of Single-Walled Carbon Nanotubes (SWNT) by Tailoring Catalyst Composition and Synthesis Conditions

    International Nuclear Information System (INIS)

    Resasco, Daniel E.

    2010-01-01

    This report shows the extensive research on the mechanism responsible for the formation of single walled carbon nanotubes in order to get control over their structural parameters (diameter and chirality). Catalyst formulations, pre-treatment conditions, and reaction conditions are described in detail as well as mechanisms to produce nanotubes structures of specific arrays (vertical forest, nanotube pillars). Applications of SWNT in different fields are also described in this report. In relation to this project five students have graduated (3 PhD and 2 MS) and 35 papers have been published.

  13. A simple approach for synthesis of TiO{sub 2} nanotubes with through-hole morphology

    Energy Technology Data Exchange (ETDEWEB)

    Kant, Krishna; Losic, Dusan [University of South Australia, Ian Wark Research Institute, Mawson lakes, SA (Australia)

    2009-07-15

    The present work reports a simple approach for fabrication of self-standing titania (TiO{sub 2}) nanotube membranes with through-hole morphology. The method is hydrofluoric acid free and the pore opening of TiO{sub 2}nanotubes is performed by electrochemical thinning of the oxide barrier layer. A reduction of anodization voltage was applied at the end of the anodization process to cause a successful removal of the remaining barrier layer from the TiO{sub 2} nanotubes during their detachment from the underlying titanium substrate. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  14. Catalyst Design Using Nanoporous Iron for the Chemical Vapor Deposition Synthesis of Single-Walled Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Tarek M. Abdel-Fattah

    2013-01-01

    Full Text Available Single-walled carbon nanotubes (SWNTs have been synthesized via a novel chemical vapor deposition (CVD approach utilizing nanoporous, iron-supported catalysts. Stable aqueous dispersions of the CVD-grown nanotubes using an anionic surfactant were also obtained. The properties of the as-produced SWNTs were characterized through atomic force microscopy and Raman spectroscopy and compared with purified SWNTs produced via the high-pressure CO (HiPCO method as a reference, and the nanotubes were observed with greater lengths than those of similarly processed HiPCO SWNTs.

  15. TiO2/carbon nanotube hybrid nanostructures: Solvothermal synthesis and their visible light photocatalytic activity

    International Nuclear Information System (INIS)

    Tian Lihong; Ye Liqun; Deng Kejian; Zan Ling

    2011-01-01

    MWCNT/TiO 2 hybrid nanostructures were prepared via solvothermal synthesis and sol-gel method with benzyl alcohol as a surfactant. As-prepared hybrid materials were characterized by X-ray diffraction, transmission electron microscopy, UV-vis diffuse reflectance spectra and X-ray photoelectron spectroscopy. The results showed that MWCNTs were uniformly decorated with anatase nanocrystals in solvothermal condition, but MWCNTs were embedded in a majority of TiO 2 nanoparticles by sol-gel method. When the weight ratio of MWCNTs to TiO 2 was 20%, MWCNT/TiO 2 hybrid nanostructures prepared by solvothermal synthesis exhibited higher visible-light-driven photocatalytic activity than that prepared by sol-gel method. Post-annealing of MWCNT/TiO 2 nanostructures at 400 deg. C resulted in the formation of the carbonaceous Ti-C bonds on the interface between TiO 2 and MWCNTs, which enhanced the photoabsorbance of the hybrid materials in the visible light region and improved the visible-light degradation efficiency of methylene blue. - Graphical abstract: MWCNT/TiO 2 nanostructures have been prepared by solvothermal method, which exhibited higher visible-light-driven photocatalytic activity than that prepared by sol-gel method. The carbonaceous Ti-C bonds on the interface between TiO 2 and MWCNTs enhanced the photoabsorbance of the hybrid materials in the visible light region. Highlights: → Anatase TiO 2 nanoparticles were anchored on CNTs surface uniformly via solvothermal method → The morphology facilitated the electron transfer between CNTs and TiO 2 → Ti-C bonds extended the absorption of MWCNT/TiO 2 to the whole visible light region. → The hybrid nanostructures showed enhanced visible-light induced photocatalytic activity.

  16. Control of growth mode of multiwalled carbon nanotubes

    International Nuclear Information System (INIS)

    Nguyen Hong Quang; Kim, Do-Hyung

    2009-01-01

    We have conducted an experimental study to investigate the synthesis of multi-walled carbon nanotubes (CNTs) by a dc plasma-enhanced chemical vapour deposition (PECVD) technique. The synthesis of base and tip-type of CNTs was selectively controlled by changing the catalyst size, catalyst film thickness correlated with altering the NH 3 pretreatment plasma current. These types of CNT showed distinctive properties in nanotube structure, growth rate and vertical alignment, which were confirmed by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and in situ optical interference measurement. The vertically aligned behaviour of CNT was systematically studied by using a fine-patterned catalyst layer with diverse critical dimensions. Freestanding single CNT was successfully realized by optimum tip-type CNT growth, conventional photolithography and wet-etch process.

  17. Atomic Layer Deposition of Pd Nanoparticles on TiO₂ Nanotubes for Ethanol Electrooxidation: Synthesis and Electrochemical Properties.

    Science.gov (United States)

    Assaud, Loïc; Brazeau, Nicolas; Barr, Maïssa K S; Hanbücken, Margrit; Ntais, Spyridon; Baranova, Elena A; Santinacci, Lionel

    2015-11-11

    Palladium nanoparticles are grown on TiO2 nanotubes by atomic layer deposition (ALD), and the resulting three-dimensional nanostructured catalysts are studied for ethanol electrooxidation in alkaline media. The morphology, the crystal structure, and the chemical composition of the Pd particles are fully characterized using scanning and transmission electron microscopies, X-ray diffraction, and X-ray photoelectron spectroscopy. The characterization revealed that the deposition proceeds onto the entire surface of the TiO2 nanotubes leading to the formation of well-defined and highly dispersed Pd nanoparticles. The electrooxidation of ethanol on Pd clusters deposited on TiO2 nanotubes shows not only a direct correlation between the catalytic activity and the particle size but also a steep increase of the response due to the enhancement of the metal-support interaction when the crystal structure of the TiO2 nanotubes is modified by annealing at 450 °C in air.

  18. 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.

  19. Synthesis and optical properties of novel organic-inorganic hybrid nanolayer structure semiconductors

    International Nuclear Information System (INIS)

    Zhang Sanjun; Lanty, Gaetan; Lauret, Jean-Sebastien; Deleporte, Emmanuelle; Audebert, Pierre; Galmiche, Laurent

    2009-01-01

    We report on the synthesis of some novel organic-inorganic hybrid 2D perovskite semiconductors (R-(CH 2 ) n NH 3 ) 2 PbX 4 . These semiconductors are self-assembled intercalation nanolayers and have a multi-quantum-well energy level structure. We systematically vary the characteristic of organic groups (R-(CH 2 ) n NH 3 + ) to study the relationship between their structures and the optical properties of (R-(CH 2 ) n NH 3 ) 2 PbX 4 . From optical absorption and photoluminescence spectroscopy experiments performed on series of samples, we find some trends of choosing the organic groups to improve the optical performance of (R-(CH 2 ) n NH 3 ) 2 PbX 4 . A new organic group, which allows synthesis of nanolayer perovskite semiconductors with quite high photoluminescence efficiency and better long-term stability, has been found.

  20. Synthesis of chemically bonded graphene/carbon nanotube composites and their application in large volumetric capacitance supercapacitors.

    Science.gov (United States)

    Jung, Naeyoung; Kwon, Soongeun; Lee, Dongwook; Yoon, Dong-Myung; Park, Young Min; Benayad, Anass; Choi, Jae-Young; Park, Jong Se

    2013-12-17

    Chemically bonded graphene/carbon nanotube composites as flexible supercapacitor electrode materials are synthesized by amide bonding. Carbon nanotubes attached along the edges and onto the surface of graphene act as spacers to increase the electrolyte-accessible surface area. Our lamellar structure electrodes demonstrate the largest volumetric capacitance (165 F cm(-3) ) ever shown by carbon-based electrodes. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Self-assembling Synthesis of Vanadium Oxide Nanotubes and Simple Determination of the Content of Ⅴ(Ⅳ)

    Institute of Scientific and Technical Information of China (English)

    MAI Li-qiang; CHEN Wen; XU Qing; ZHU Quan-yao; HAN Chun-hua; PENG Jun-feng

    2003-01-01

    High-yielding low-cost vanadium oxide nanotubes were prepared by the hydrothermal self-assembling process from vanadium pentoxide and organic molecules as structure-directing templates. Moreover, a new method was discovered for determining the content of V (Ⅳ) in vanadium oxide nanotubes by thermogravimetric analysis ( TGA ). This method is simple, precise and feasible and can be extended to determine the content of low oxidation state in the other transition metal oxide nanomaterials.

  2. Plasma-induced synthesis of Pt nanoparticles supported on TiO2 nanotubes for enhanced methanol electro-oxidation

    Science.gov (United States)

    Su, Nan; Hu, Xiulan; Zhang, Jianbo; Huang, Huihong; Cheng, Jiexu; Yu, Jinchen; Ge, Chao

    2017-03-01

    A Pt/C/TiO2 nanotube composite catalyst was successfully prepared for enhanced methanol electro-oxidation. Pt nanoparticles with a particle size of 2 nm were synthesized by plasma sputtering in water, and anatase TiO2 nanotubes with an inner diameter of approximately 100 nm were prepared by a simple two-step anodization method and annealing process. Field-emission scanning electron microscopy images indicated that the different morphologies of TiO2 synthesized on the surface of Ti foils were dependent on the different anodization parameters. The electrochemical performance of Pt/C/TiO2 catalysts for methanol oxidation showed that TiO2 nanotubes were more suitable for use as Pt nanoparticle support materials than irregular TiO2 short nanorods due to their tubular morphology and better electronic conductivity. X-ray photoelectron spectroscopy characterization showed that the binding energies of the Pt 4f of the Pt/C/TiO2 nanotubes exhibited a slightly positive shift caused by the relatively strong interaction between Pt and the TiO2 nanotubes, which could mitigate the poisoning of the Pt catalyst by COads, and further enhance the electrocatalytic performance. Thus, the as-obtained Pt/C/TiO2 nanotubes composites may become a promising catalyst for methanol electro-oxidation.

  3. Synthesis and characterization of optically transparent epoxy matrix nanocomposites

    International Nuclear Information System (INIS)

    Esposito Corcione, C.; Manera, M.G.; Maffezzoli, A.; Rella, R.

    2009-01-01

    In this work optically transparent nanocomposites were prepared and characterized from an optical and morphological point of view. An organically modified boehmite was added at different concentrations in a diglycidyl ether of bisphenol A (DGEBA) epoxy matrix, hardened with a polyether diamine. Nanocomposites were characterized structurally by X-ray diffraction (XRD), optically by UV-Vis-NIR spectrophotometry and their morphology was investigated by Atomic Force Microscopy (AFM). Morphological investigation reveals the presence of boehmite particles dispersed in the epoxy matrix in different dimensions ranging from ten to hundreds of nanometers; some aggregation in the particles is the tendency noticed in the AFM images. The acquisition of multiple AFM images in different areas of the sample was used for a statistical analysis of the volumetric distribution of boehmite aggregates. The obtained result, (3.6 ± 0.3)%vol, is well comparable to thermogravimetric analysis.

  4. Lanthanides-clay nanocomposites: Synthesis, characterization and optical properties

    International Nuclear Information System (INIS)

    Celedon, Salvador; Quiroz, Carolina; Gonzalez, Guillermo; Sotomayor Torres, Clivia M.; Benavente, Eglantina

    2009-01-01

    Complexes of Europium(III) and Terbium(III) with 2,2-bipyridine and 1,10-phenanthroline were inserted into Na-bentonite by ion exchange reactions at room temperature. The products display interlaminar distances and stoichiometries in agreement with the ion exchange capacity and the interlayer space available in the clay. The optical properties of the intercalates, being qualitatively similar to those of the free complexes, are additionally improved with respect to exchange processes with the medium, especially in a moist environment. The protection again hydrolysis, together with the intensity of the optical transition 5 D 0 - 5 F 2 observed in the nanocomposite, makes these products promising for the development of novel optical materials

  5. NONLINEAR OPTICAL MOLECULAR CRYSTAL BASED ON 2,6-DIAMINOPYRIDINE: SYNTHESIS AND CHARACTERIZATION

    Directory of Open Access Journals (Sweden)

    I. M. Pavlovetc

    2014-05-01

    Full Text Available The paper deals with investigation of a new nonlinear optical material based on nonlinear optical chromophore (4-Nitrophenol and aminopyridine (2,6-Diaminopyridine. Calculation results are presented for molecular packing in the crystalline compound, based on the given components. According to these results the finite material must have a noncentrosymmetric lattice, which determines the presence of the second order nonlinear optical response. Investigations carried out in this work confirm these calculations. Results of experiments are given describing the co-crystallization of these components and the following re-crystallization of the obtained material. In order to get a monocrystal form, the optimal conditions for the synthesis of molecular crystals based on these components are determined. Sufficiently large homogeneous crystals are obtained, that gave the possibility to record their spectra in the visible and near infrared parts of the spectrum, to determine their nonlinear optical properties and the level of homogeneity. Their optical (optical transmission and optical laser damage threshold and nonlinear optical properties are presented. For observation and measurement of the nonlinear optical properties an installation was built which implements the comparative method for measurements of nonlinear optical properties. A potassium titanyl oxide phosphate crystal was used as a sample for comparison. Results are given for the conversion efficiency of the primary laser radiation in the second optical harmonic relative to the signal obtained on the potassium titanyl oxide phosphate crystal. Obtained results show that the molecular co-crystal based on 2,6-Diaminopyridine is a promising nonlinear optical material for generating the second optical harmonic on the Nd: YAG laser (532 nm.

  6. Near infrared optical biosensor based on peptide functionalized single-walled carbon nanotubes hybrids for 2,4,6-trinitrotoluene (TNT) explosive detection.

    Science.gov (United States)

    Wang, Jin

    2018-06-01

    A near infrared (NIR) optical biosensor based on peptide functionalized single-walled carbon nanotubes (SWCNTs) hybrids for 2,4,6-trinitrotoluene (TNT) explosive detection was developed. The TNT binding peptide was directly anchored on the sidewall of the SWCNTs using the π-π interaction between the aromatic amino acids and SWCNTs, forming the peptide-SWCNTs hybrids for near infrared absorption spectra measurement. The evidence of the morphology of peptide-SWCNTs hybrids was obtained using atomic force microscopy (AFM). The results demonstrated that peptide-SWCNTs hybrids based NIR optical biosensor exhibited sensitive and highly selective for TNT explosive determination, addressing a promising optical biosensor for security application. Copyright © 2018. Published by Elsevier Inc.

  7. Study towards diversity oriented synthesis of optically active ...

    Indian Academy of Sciences (India)

    oxidation procedures, all the reactions were carried out either in argon or nitrogen .... ring solution of alcohol 9a (300mg, 0.70mmol) dis- solved in 20 mL of DCM ..... In summary, diversity-oriented approach for the synthe- sis of optically active, ...

  8. Barium titanate inverted opals-synthesis, characterization, and optical properties

    Energy Technology Data Exchange (ETDEWEB)

    Soten, I.; Miguez, H.; Yang, S.M.; Petrov, S.; Coombs, N.; Tetreault, N.; Ozin, G.A. [Toronto Univ., ON (Canada). Dept. of Chemistry; Matsuura, N.; Ruda, H.E. [Toronto Univ., ON (Canada). Dept. of Metallurgy and Materials Science

    2002-01-01

    The engineering of cubic or tetragonal polymorphs of nanocrystalline barium titanate inverted opals has been achieved by thermally induced transformations. Optical characterization demonstrated photonic crystal behavior of the opals. The tuning of the ferroelectric-paraelectric transition around the Curie temperature is shown in this paper. (orig.)

  9. Synthesis of coupled resonator optical waveguides by cavity aggregation.

    Science.gov (United States)

    Muñoz, Pascual; Doménech, José David; Capmany, José

    2010-01-18

    In this paper, the layer aggregation method is applied to coupled resonator optical waveguides. Starting from the frequency transfer function, the method yields the coupling constants between the resonators. The convergence of the algorithm developed is examined and the related parameters discussed.

  10. Synthesis and characterization of new optically active poly(amide

    African Journals Online (AJOL)

    Preferred Customer

    Six new optically active poly(amide-imide)s (8a-f) were synthesized through the direct ... polyimides are widely used in the semiconductor and electronic packaging ... chiral polymers is of particular interest from the viewpoint of material science ...

  11. Optical materials

    International Nuclear Information System (INIS)

    Poker, D.B.; Ortiz, C.

    1989-01-01

    This book reports on: Diamond films, Synthesis of optical materials, Structure related optical properties, Radiation effects in optical materials, Characterization of optical materials, Deposition of optical thin films, and Optical fibers and waveguides

  12. Synthesis and optical properties of CdS/PVA nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Khanna, P K [Nanomaterials Laboratory, Centre for Materials for Electronics Technology (C-MET), Panchawati, Off Pashan Road, Pune 411008 (India); Gokhale, R R [Nanomaterials Laboratory, Centre for Materials for Electronics Technology (C-MET), Panchawati, Off Pashan Road, Pune 411008 (India); Subbarao, V V.V.S. [Nanomaterials Laboratory, Centre for Materials for Electronics Technology (C-MET), Panchawati, Off Pashan Road, Pune 411008 (India); Singh, Narendra [Nanomaterials Laboratory, Centre for Materials for Electronics Technology (C-MET), Panchawati, Off Pashan Road, Pune 411008 (India); Jun, K -W [Korea Research Institute of Chemical Technology, P.O. Box 107, Yuseong, Daejeon 305-600 (Korea, Republic of); Das, B K [Nanomaterials Laboratory, Centre for Materials for Electronics Technology (C-MET), Panchawati, Off Pashan Road, Pune 411008 (India)

    2005-12-15

    Yellow and orange light emission from nanoparticles of cadmium sulphide embedded in polyvinyl alcohol (PVA) has been observed as thin films. The synthesis of CdS embedded in PVA has been performed via two different routes at room temperature and the composite films have been prepared by vacuum evaporation of solvent on a glass surface. The absorption spectra show a blue shift of more than 80 nm as compared to bulk CdS band-gap. The photoluminescence studies indicate the air stable light emission from the films. Bright light emission at 515 nm (2.41 eV) has been observed without using PVA.

  13. All carbon nanotubes are not created equal

    International Nuclear Information System (INIS)

    Geohegan, David B.; Puretzky, Alexander A.; Rouleau, Christopher M.

    2010-01-01

    This chapter presents the various factors that enter into consideration when choosing the source of carbon nanotubes for a specific application. Carbon nanotubes are giant molecules made of pure carbon. They have captured the imagination of the scientific community by the unique structure that provides superior physical, chemical, and electrical properties. However, a surprisingly wide disparity exists between the intrinsic properties determined under ideal conditions and the properties that carbon nanotubes exhibit in real world situations. The lack of uniformity in carbon nanotube properties is likely to be the main obstacle holding back the development of carbon nanotube applications. This tutorial addresses the nonuniformity of carbon nanotube properties from the synthesis standpoint. This synthesis-related nonuniformity is on top of the intrinsic chirality distribution that gives the ∼1:2 ratio of metallic to semiconducting nanotubes. From the standpoint of carbon bonding chemistry the variation in the quality and reproducibility of carbon nanotube materials is not unexpected. It is an intrinsic feature that is related to the metastability of carbon structures. The extent to which this effect is manifested in carbon nanotube formation is governed by the type and the kinetics of the carbon nanotube synthesis reaction. Addressing this variation is critical if nanotubes are to live up to the potential already demonstrated by their phenomenal physical properties.

  14. Interfacial Polycondensation Synthesis of Optically Sensitive Polyurea Microcapsule

    Directory of Open Access Journals (Sweden)

    Weidong Lai

    2014-01-01

    Full Text Available TMPTA prepolymer resin and photoinitiators of ITX/TPO had been encapsulated in core-shell structured microcapsules as optical responding ingredients based on interfacial polycondensation method, and polyurea structured microcapsule shell had been formed on the sheared O/W interface. The synthesized microcapsule had regular core-shell structure with the diameter of about 0.455 μm and shell thickness of about 40 nm. UV-visible absorption spectra indicated that the encapsulated ITX and TPO photoinitiators could efficiently absorb UV irradiation. Under exposure, the C=C bonds absorbance of the microencapsulated TMPTA decreased rapidly and then nearly unchanged during further exposure after 30 s. This implied that the optical response was achieved by C=C bond cleavage of TMPTA monomer initiated by the photoinitiator radicals, to form network polymers in microcapsules. The relative crosslinking rate was about 50%. Due to core polymer formation, the thermal phase change temperature of exposed microcapsules was narrowed and ranged from 105 to 205°C, compared with that from 125 to 260°C of unexposed microcapsules. Furthermore, the image density decrease at longer irradiation time had also verified the optical responding function of the synthesized microcapsules in macroscopic viewpoint.

  15. Synthesis and property of novel MnO2@polypyrrole coaxial nanotubes as electrode material for supercapacitors

    Science.gov (United States)

    Yao, Wei; Zhou, Hui; Lu, Yun

    2013-11-01

    Novel MnO2@polypyrrole (PPy) coaxial nanotubes have been prepared via a simple and green approach without any surfactant and additional oxidant. Under the acidic condition, MnO2 nanotubes act as both template and oxidant to initiate the polymerization of pyrrole monomers on its fresh-activated surface. Fourier transform infrared spectra (FT-IR), X-ray diffraction patterns (XRD), thermo-gravimetric analysis data (TG) and X-ray photoelectron spectra (XPS) suggest the formation of composite structure of MnO2@PPy. Also, FESEM and TEM images intuitively confirm that the PPy shell is coated uniformly on the surface of MnO2 nanotubes. Adjusting the concentrations of sulfuric acid or adding oxidant can modulate the morphology of the products accordingly. Due to the synergic effect between MnO2 core and PPy shell, the MnO2@PPy coaxial nanotubes possess better rate capability, larger specific capacitance of 380 F g-1, doubling the specific capacitance of MnO2 nanotubes, and good capacitance retention of 90% for its initial capacitance after 1000 cycles.

  16. Synthesis, Optical Properties and Applications for New Trianguleniums Derivatives

    DEFF Research Database (Denmark)

    Santella, Marco

    The development of new types of emissive organic dyes is an exciting area of research due to the applicability of these compounds in a wide range of disciplines. Cationic triangulenium salts are highly stable carbenium ions with a planar conformation. The convenient and versatile synthetic proced...... focused on the synthesis of thioether para substituted dyes, where the reactivity of various para-methoxy substituted propeller shaped cations towards different alkyl thiols was examined. Furthermore, ringclosure reactions of these thioether bearing propellers in order to obtain trioxa...... structures. These dyes possess excellent emissive properties with possible applications as cell staining agents or as fluorescent probes. Lastly, I focused on the use of triangulenes as binding group for molecular electronics. It has been shown that TATA can form self-assembled monolayers (SAMs) on a gold...

  17. Effects of an electric field on the electronic and optical properties of zigzag boron nitride nanotubes

    Science.gov (United States)

    Chegel, Raad; Behzad, Somayeh

    2011-02-01

    We have investigated the electro-optical properties of zigzag BNNTs, under an external electric field, using the tight binding approximation. It is found that an electric field modifies the band structure and splits the band degeneracy. Also the large electric strength leads to coupling the neighbor subbands which these effects reflect in the DOS and JDOS spectrum. It has been shown that, unlike CNTs, the band gap of BNNTs can be reduced linearly by applying a transverse external electric field. Also we show that the larger diameter tubes are more sensitive than small ones. The semiconducting metallic transition can be achieved through increasing the applied fields. The number and position of peaks in the JDOS spectrum are dependent on electric field strength. It is found that at a high electric field, the two lowest subbands are oscillatory with multiple nodes at the Fermi level.

  18. Gold icosahedral nanocages: Facile synthesis, optical properties, and fragmentation under ultrasonication

    Science.gov (United States)

    Yang, Xuan; Gilroy, Kyle D.; Vara, Madeline; Zhao, Ming; Zhou, Shan; Xia, Younan

    2017-09-01

    Because of their unique optical properties, gold nanocages are excellent candidates for biomedical applications. Traditionally, they are prepared using a method that involves the galvanic replacement reaction between Ag nanocubes and HAuCl4. Here we demonstrate a different approach for the facile synthesis of Au icosahedral nanocages containing twin boundaries, as well as a compact size below 15 nm and ultrathin walls of only a few atomic layers thick. Their optical properties could be tuned by simply controlling the etching time, a result that was also validated by computational modeling. We further evaluated the feasibility of fragmenting the nanocages using ultrasonication.

  19. Semiconductor nanoparticles with spatial separation of charge carriers: synthesis and optical properties

    International Nuclear Information System (INIS)

    Vasiliev, Roman B; Dirin, Dmitry N; Gaskov, Alexander M

    2011-01-01

    The results of studies on core/shell semiconductor nanoparticles with spatial separation of photoexcited charge carriers are analyzed and generalized. Peculiarities of the electronic properties of semiconductor/semiconductor heterojunctions formed inside such particles are considered. Data on the effect of spatial separation of charge carriers on the optical properties of nanoparticles including spectral shifts of the exciton bands, absorption coefficients and electron–hole pair recombination times are presented. Methods of synthesis of core/shell semiconductor nanoparticles in solutions are discussed. Specific features of the optical properties of anisotropic semiconductor nanoparticles with the semiconductor/semiconductor junctions are noted. The bibliography includes 165 references.

  20. High-yield synthesis and optical response of gold nanostars

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Pandian Senthil [Departamento de Quimica Fisica and Unidad Asociada CSIC-Universidade de Vigo, 36310 Vigo (Spain); Pastoriza-Santos, Isabel [Departamento de Quimica Fisica and Unidad Asociada CSIC-Universidade de Vigo, 36310 Vigo (Spain); RodrIguez-Gonzalez, Benito [Departamento de Quimica Fisica and Unidad Asociada CSIC-Universidade de Vigo, 36310 Vigo (Spain); Abajo, F Javier GarcIa de [Instituto de Optica-CSIC, Serrano 121, 28006 Madrid (Spain); Liz-Marzan, Luis M [Departamento de Quimica Fisica and Unidad Asociada CSIC-Universidade de Vigo, 36310 Vigo (Spain)

    2008-01-09

    Multipod Au nanoparticles (nanostars) with single crystalline tips were synthesized in extremely high yield through the reduction of HAuCl{sub 4} in a concentrated solution of poly(vinylpyrrolidone) (PVP) in N,N-dimethylformamide (DMF), in the presence of preformed Au nanoparticle seeds, but with no need for external energy sources. Nanostar dispersions display a well-defined optical response, which was found (through theoretical modeling) to comprise a main mode confined within the tips and a secondary mode confined in the central body. Calculations of the surface enhanced Raman scattering (SERS) response additionally show that this morphology will be relevant for sensing applications.