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Sample records for mixed oxide nanocomposites

  1. Synthesis and Characterization of Mixed Metal Oxide Nanocomposite Energetic Materials

    Energy Technology Data Exchange (ETDEWEB)

    Gash, A; Pantoya, M; Jr., J S; Zhao, L; Shea, K; Simpson, R; Clapsaddle, B

    2003-11-18

    In the field of composite energetic materials, properties such as ingredient distribution, particle size, and morphology, affect both sensitivity and performance. Since the reaction kinetics of composite energetic materials are typically controlled by the mass transport rates between reactants, one would anticipate new and potentially exceptional performance from energetic nanocomposites. We have developed a new method of making nanostructured energetic materials, specifically explosives, propellants, and pyrotechnics, using sol-gel chemistry. A novel sol-gel approach has proven successful in preparing metal oxide/silicon oxide nanocomposites in which the metal oxide is the major component. Two of the metal oxides are tungsten trioxide and iron(III) oxide, both of which are of interest in the field of energetic materials. Furthermore, due to the large availability of organically functionalized silanes, the silicon oxide phase can be used as a unique way of introducing organic additives into the bulk metal oxide materials. As a result, the desired organic functionality is well dispersed throughout the composite material on the nanoscale. By introducing a fuel metal into the metal oxide/silicon oxide matrix, energetic materials based on thermite reactions can be fabricated. The resulting nanoscale distribution of all the ingredients displays energetic properties not seen in its microscale counterparts due to the expected increase of mass transport rates between the reactants. The synthesis and characterization of these metal oxide/silicon oxide nanocomposites and their performance as energetic materials will be discussed.

  2. Synthesis and Characterization of Mixed Metal Oxide Nanocomposite Energetic Materials

    Energy Technology Data Exchange (ETDEWEB)

    Clapsaddle, B; Gash, A; Plantier, K; Pantoya, M; Jr., J S; Simpson, R

    2004-04-27

    In the field of composite energetic materials, properties such as ingredient distribution, particle size, and morphology affect both sensitivity and performance. Since the reaction kinetics of composite energetic materials are typically controlled by the mass transport rates between reactants, one would anticipate new and potentially exceptional performance from energetic nanocomposites. We have developed a new method of making nanostructured energetic materials, specifically explosives, propellants, and pyrotechnics, using sol-gel chemistry. A novel sol-gel approach has proven successful in preparing metal oxide/silicon oxide nanocomposites in which the metal oxide is the major component. By introducing a fuel metal, such as aluminum, into the metal oxide/silicon oxide matrix, energetic materials based on thermite reactions can be fabricated. Two of the metal oxides are tungsten trioxide and iron(III) oxide, both of which are of interest in the field of energetic materials. In addition, due to the large availability of organically functionalized silanes, the silicon oxide phase can be used as a unique way of introducing organic additives into the bulk metal oxide materials. These organic additives can cause the generation of gas upon ignition of the materials, therefore resulting in a composite material that can perform pressure/volume work. Furthermore, the desired organic functionality is well dispersed throughout the composite material on the nanoscale with the other components, and is therefore subject to the same increased reaction kinetics. The resulting nanoscale distribution of all the ingredients displays energetic properties not seen in its microscale counterparts due to the expected increase of mass transport rates between the reactants. The synthesis and characterization of iron(III) oxide/organosilicon oxide nanocomposites and their performance as energetic materials will be discussed.

  3. Nanocomposites of polyimide and mixed oxide nanoparticles for high performance nanohybrid gate dielectrics in flexible thin film transistors

    Science.gov (United States)

    Kim, Ju Hyun; Hwang, Byeong-Ung; Kim, Do-Il; Kim, Jin Soo; Seol, Young Gug; Kim, Tae Woong; Lee, Nae-Eung

    2017-01-01

    Organic gate dielectrics in thin film transistors (TFTs) for flexible display have advantages of high flexibility yet have the disadvantage of low dielectric constant (low-k). To supplement low-k characteristics of organic gate dielectrics, an organic/inorganic nanocomposite insulator loaded with high-k inorganic oxide nanoparticles (NPs) has been investigated but high loading of high-k NPs in polymer matrix is essential. Herein, compositing of over-coated polyimide (PI) on self-assembled (SA) layer of mixed HfO2 and ZrO2 NPs as inorganic fillers was used to make dielectric constant higher and leakage characteristics lower. A flexible TFT with lower the threshold voltage and high current on/off ratio could be fabricated by using the hybrid gate dielectric structure of the nanocomposite with SA layer of mixed NPs on ultrathin atomic-layer deposited Al2O3.

  4. Mesoporous metal oxide graphene nanocomposite materials

    Science.gov (United States)

    Liu, Jun; Aksay, Ilhan A.; Kou, Rong; Wang, Donghai

    2016-05-24

    A nanocomposite material formed of graphene and a mesoporous metal oxide having a demonstrated specific capacity of more than 200 F/g with particular utility when employed in supercapacitor applications. A method for making these nanocomposite materials by first forming a mixture of graphene, a surfactant, and a metal oxide precursor, precipitating the metal oxide precursor with the surfactant from the mixture to form a mesoporous metal oxide. The mesoporous metal oxide is then deposited onto a surface of the graphene.

  5. Nanocomposite of graphene and metal oxide materials

    Science.gov (United States)

    Liu, Jun; Aksay, Ilhan A.; Choi, Daiwon; Wang, Donghai; Yang, Zhenguo

    2013-10-15

    Nanocomposite materials comprising a metal oxide bonded to at least one graphene material. The nanocomposite materials exhibit a specific capacity of at least twice that of the metal oxide material without the graphene at a charge/discharge rate greater than about 10 C.

  6. Sol-Gel/Hydrothermal Synthesis of Mixed Metal Oxide

    African Journals Online (AJOL)

    Mixed metal oxides of titanium and zinc nanocomposites were prepared through sol-gel method under hydrothermal ... the production of TiO -ZnO nanoparticles use. 2 either titanium ... involved using titanium sulphate and thioacetamide for ...

  7. Cellulose nanocrystal reinforced oxidized natural rubber nanocomposites.

    Science.gov (United States)

    Mariano, Marcos; El Kissi, Nadia; Dufresne, Alain

    2016-02-10

    Natural rubber (NR) latex particles were oxidized using KMnO4 as oxidant to promote the insertion of hydroxyl groups in the surface polyisoprene chains. Different degrees of oxidation were investigated. Both unoxidized and oxidized NR (ONR) latex were used to prepare nanocomposite films reinforced with cellulose nanocrystals (CNCs) by casting/evaporation. The oxidation of NR was carried out to promote chemical interactions between the hydroxyl groups of ONR with those of CNCs through hydrogen bonding. The effect of the degree of oxidation of the NR latex on the rheological behavior of CNC/NR and CNC/ONR suspensions, as well as on the mechanical, swelling and thermal properties of ensuing nanocomposites was investigated. Improved properties were observed for intermediate degrees of oxidation but they were found to degrade for higher oxidation levels.

  8. Graphene oxide - Polyvinyl alcohol nanocomposite based electrode material for supercapacitors

    Science.gov (United States)

    Pawar, Pranav Bhagwan; Shukla, Shobha; Saxena, Sumit

    2016-07-01

    Supercapacitors are high capacitive energy storage devices and find applications where rapid bursts of power are required. Thus materials offering high specific capacitance are of fundamental interest in development of these electrochemical devices. Graphene oxide based nanocomposites are mechanically robust and have interesting electronic properties. These form potential electrode materials efficient for charge storage in supercapacitors. In this perspective, we investigate low cost graphene oxide based nanocomposites as electrode material for supercapacitor. Nanocomposites of graphene oxide and polyvinyl alcohol were synthesized in solution phase by integrating graphene oxide as filler in polyvinyl alcohol matrix. Structural and optical characterizations suggest the formation of graphene oxide and polyvinyl alcohol nanocomposites. These nanocomposites were found to have high specific capacitance, were cyclable, ecofriendly and economical. Our studies suggest that nanocomposites prepared by adding 0.5% wt/wt of graphene oxide in polyvinyl alcohol can be used an efficient electrode material for supercapacitors.

  9. 3D Printing Biocompatible Polyurethane/Poly(lactic acid)/Graphene Oxide Nanocomposites: Anisotropic Properties.

    Science.gov (United States)

    Chen, Qiyi; Mangadlao, Joey Dacula; Wallat, Jaqueline; De Leon, Al; Pokorski, Jonathan K; Advincula, Rigoberto C

    2017-02-01

    Blending thermoplastic polyurethane (TPU) with poly(lactic acid) (PLA) is a proven method to achieve a much more mechanically robust material, whereas the addition of graphene oxide (GO) is increasingly applied in polymer nanocomposites to tailor further their properties. On the other hand, additive manufacturing has high flexibility of structure design which can significantly expand the application of materials in many fields. This study demonstrates the fused deposition modeling (FDM) 3D printing of TPU/PLA/GO nanocomposites and its potential application as biocompatible materials. Nanocomposites are prepared by solvent-based mixing process and extruded into filaments for FDM printing. The addition of GO largely enhanced the mechanical property and thermal stability of the nanocomposites. Interestingly, we found that the mechanical response is highly dependent on printing orientation. Furthermore, the 3D printed nanocomposites exhibit good biocompatibility with NIH3T3 cells, indicating promise as biomaterials scaffold for tissue engineering applications.

  10. Assessment of morphology and property of graphene oxide-hydroxypropylmethylcellulose nanocomposite films.

    Science.gov (United States)

    Ghosh, Tapas Kumar; Gope, Shirshendu; Mondal, Dibyendu; Bhowmik, Biplab; Mollick, Md Masud Rahaman; Maity, Dipanwita; Roy, Indranil; Sarkar, Gunjan; Sadhukhan, Sourav; Rana, Dipak; Chakraborty, Mukut; Chattopadhyay, Dipankar

    2014-05-01

    Graphene oxide (GO) was synthesized by Hummer's method and characterized by using Fourier transform infrared spectroscopy and Raman spectroscopy. The as synthesized GO was used to make GO/hydroxypropylmethylcellulose (HPMC) nanocomposite films by the solution mixing method using different concentrations of GO. The nanocomposite films were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and thermo-gravimetric analysis. Mechanical properties, water absorption property and water vapor transmission rate were also measured. XRD analysis showed the formation of exfoliated HPMC/GO nanocomposites films. The FESEM results revealed high interfacial adhesion between the GO and HPMC matrix. The tensile strength and Young's modulus of the nanocomposite films containing the highest weight percentage of GO increased sharply. The thermal stability of HPMC/GO nanocomposites was slightly better than pure HPMC. The water absorption and water vapor transmission rate of HPMC film was reduced with the addition of up to 1 wt% GO.

  11. Synthesis and characterization of Y2O3-reduced graphene oxide nanocomposites for photocatalytic applications

    Science.gov (United States)

    Saravanan, T.; Anandan, P.; Azhagurajan, M.; Arivanandhan, M.; Pazhanivel, K.; Hayakawa, Y.; Jayavel, R.

    2016-07-01

    Yittrium oxide (Y2O3)-reduced graphene oxide (rGO) nanocomposite was prepared by a low temperature solution process by mixing different weight ratios of chemically derived rGO and Y2O3. The structural properties of nanocomposite materials have been analyzed by x-ray diffraction. Laser Raman spectroscopic study further confirmed the formation of the nanocomposite materials. The morphology of the nanocomposite has been analyzed by field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) images. From the FE-SEM and TEM images, it was found that the nanocrystals of Y2O3 were interpolated in the graphene sheets. X-ray photoelectron spectroscopy (XPS) analysis confirmed that the rGO has a reasonable amount of C-O groups as the doublet was observed in the C 1s spectrum. Moreover, the O 1s peak illustrates the doublet peaks which confirms the presence of OH and other functional groups at the surfaces of rGO. Electrochemical behavior of the nanocomposite was studied by cyclic voltammetric studies. The nanocomposite with higher weight percent of rGO shows better photocatalytic performance compared to the samples with low weight percent of rGO. The photocatalytic characteristics of the nanocomposite have been discussed based on the XPS results. The presence of hydroxyl group in the rGO of nanocomposites increases the OH radical formation and suppresses the recombination of excitons, which is responsible for the rapid decomposition of dye molecules.

  12. Novel porous graphene oxide and hydroxyapatite nanosheets-reinforced sodium alginate hybrid nanocomposites for medical applications

    Energy Technology Data Exchange (ETDEWEB)

    Xiong, Guangyao [School of Mechanical and Electrical Engineering, East China Jiaotong University, Nanchang 330013 (China); Luo, Honglin [Research Institute of Biomaterials and Transportation, East China Jiaotong University, Nanchang 330013 (China); School of Materials Science and Engineering, Tianjin Key Laboratory of Composite and Functional Materials, Key Laboratory of Advanced Ceramics and Machining Technology, Ministry of Education, Tianjin University, Tianjin 300072 (China); Zuo, Guifu [Hebei Provincial Key Laboratory of Inorganic Nonmetallic Materials, College of Materials Science and Engineering, Hebei United University, Tangshan 063009 (China); Ren, Kaijing [Department of Joint Surgery, Tianjin Hospital, Tianjin 300211 (China); Wan, Yizao, E-mail: yzwantju@126.com [Research Institute of Biomaterials and Transportation, East China Jiaotong University, Nanchang 330013 (China); School of Materials Science and Engineering, Tianjin Key Laboratory of Composite and Functional Materials, Key Laboratory of Advanced Ceramics and Machining Technology, Ministry of Education, Tianjin University, Tianjin 300072 (China)

    2015-09-15

    Graphene oxide (GO) and hydroxyapatite (HAp) are frequently used as reinforcements in polymers to improve mechanical and biological properties. In this work, novel porous hybrid nanocomposites consisting of GO, HAp, and sodium alginate (SA) have been prepared by facile solution mixing and freeze drying in an attempt to obtain a scaffold with desirable mechanical and biological properties. The as-prepared porous GO/HAp/SA hybrid nanocomposites were characterized by SEM, XRD, FTIR, TGA, and mechanical testing. In addition, preliminary cell behavior was assessed by CCK8 assay. It is found that the GO/HAp/SA nanocomposites show improved compressive strength and modulus over neat SA and HAp/SA nanocomposites. CCK8 results reveal that the GO/HAp/SA nanocomposites show enhanced cell proliferation over neat SA and GO/SA nanocomposite. It has been demonstrated that GO/HAp20/SA holds promise in bone tissue engineering. - Graphical abstract: Display Omitted - Highlights: • Graphene oxide (GO), hydroxyapatite (HAp), and alginate (SA) nanocomposites were fabricated. • The novel porous composites were prepared by solution mixture and freeze drying. • The GO/HAp/SA had porous structure with porosity > 85% and pore size > 150 μm. • The GO/HAp/SA exhibited improved mechanical properties over HAp/SA counterparts. • The GO/HAp/SA showed enhanced cell proliferation over GO/SA counterparts.

  13. Electrorheological fluids of polypyrrole-tin oxide nanocomposite particles

    Science.gov (United States)

    Kim, Young Dae; Yoon, Dae Jeon

    2016-11-01

    The electrorheological (ER) response of polypyrrole(PPy)-tin oxide nanocomposite ER fluids increased with the increase in the tin oxide/pyrrole weight ratio, particle volume fraction, and electric field strength. The dielectric properties and direct current (dc) conductivity of PPy-tin oxide nanocomposite particles and the dielectric properties of PPy-tin oxide nanocomposite ER fluids agreed with the ER behaviors. The ER behavior of PPy-tin oxide nanocomposite ER fluids was well fitted to τ = 0.0248 ϕE 1.5 and showed a transition from that of the polarization model ( τ ˜ E 2) to that of the conduction model ( τ ˜ E 1.5) depending on the tin oxide/pyrrole weight ratio.

  14. Cure kinetics and chemorheology of EPDM/graphene oxide nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Allahbakhsh, Ahmad [Department of Polymer Engineering, Islamic Azad University, South Tehran Branch, 17776-13651 Tehran (Iran, Islamic Republic of); Mazinani, Saeedeh, E-mail: s.mazinani@aut.ac.ir [Amirkabir Nanotechnology Research Institute (ANTRI), Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Kalaee, Mohammad Reza [Department of Polymer Engineering, Islamic Azad University, South Tehran Branch, 17776-13651 Tehran (Iran, Islamic Republic of); Sharif, Farhad [Department of Polymer Engineering and Color Technology, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of)

    2013-07-10

    Graphical abstract: - Highlights: • Graphene oxide content and dispersion as effective parameters on cure kinetics. • Graphene oxide as an effective controlling factor of crosslink density. • Interaction of graphene oxide with curing system (ZnO) during curing process. - Abstract: In this study, the effect of graphene oxide on cure behavior of ethylene–propylene–diene rubber (EPDM) nanocomposite is studied. In this regard, the cure kinetics of nanocomposite is studied employing different empirical methods. The required activation energy of nth-order cure process shows about 160 kJ/mol increments upon 5 phr graphene oxide loading compared to 1 phr graphene oxide loading. However, the required activation energy is significantly reduced followed by incorporation of graphene oxide in nanocomposites compared to neat EPDM sample. Furthermore, the effect of graphene oxide on structural properties of nanocomposites during the cure process is studied using X-ray diffraction, scanning electron microscopy and Fourier transform infrared spectrometry techniques. As the results show, graphene oxide interestingly affects the structure of zinc oxide during the vulcanization process. This behavior could be probably related to high tendency of zinc oxide to react with oxidized surface of graphene oxide.

  15. Synthesis, Characteristics, and Material Properties Dataset of Bi:DyIG-Oxide Garnet-Type Nanocomposites

    Directory of Open Access Journals (Sweden)

    M. Nur-E-Alam

    2015-01-01

    Full Text Available The fabrication, annealing crystallization processes, and material properties of (Bi,Dy3(Fe,Ga5O12:Bi2O3 nanocomposites are investigated and summarized. The stoichiometry of these nanocomposites is optimized for magnetooptic applications using the approach of stoichiometry adjustment (implemented by means of varying RF power densities applied to the sputtering targets used to prepare the nanocomposite thin films. The crystallization processes for all developed batches of as-deposited films are carried out by annealing runs at different temperatures and process durations. This paper describes the methodologies used to optimize the compositions (by calculating the volumetric fractions of excess bismuth oxide to be mixed with the garnet-stoichiometry species during cosputtering processes and to obtain the optical and magnetooptical properties data and presents the materials properties summary of garnet-bismuth oxide thin film composites as well.

  16. Preparation and properties of poly(vinylidene fluoride nanocomposites blended with graphene oxide coated silica hybrids

    Directory of Open Access Journals (Sweden)

    Q. Fu

    2012-04-01

    Full Text Available Graphene oxide coated silica hybirds (SiO2-GO were fabricated through electrostatic assembly in this work, then blended with poly(vinylidene fluoride (PVDF by solution mixing to make PVDF nanocomposites. The interfacial interaction was investigated by scanning electron microscopy (SEM, polarized optical microscopy (POM and Fourier transform infrared spectroscopy (FTIR. The results showed that the interfacial interaction was enhanced by adding of SiO2-GO and strong hydrogen bonds were observed. The as-made nanocomposites were investigated using standard tensile test and dynamic mechanical analysis (DMA measurements, mechanical properties of PVDF with SiO2-GO hybrids showed limited improvement.

  17. Evaluation of reduced graphene oxide/ZnO effect on properties of PVDF nanocomposite films

    Science.gov (United States)

    Jaleh, B.; Jabbari, A.

    2014-11-01

    In this work, we report the preparation and characterization of PVDF/reduced graphene oxide (RGO)-ZnO nanocomposite films via synthesis of reduced graphene oxide-ZnO nanocomposite by solution casting method. Different weight ratios of RGO-ZnO nanocomposites were produced and compounded with PVDF by solution mixing. The compounding was followed by solution casting and drying to form nanocomposite films. Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction techniques (XRD), revealed an obvious α to β-phase transformation compared to pure PVDF which a maximum content of 83% for β-phase was calculated by using FTIR techniques. The morphology of the nanocomposites was investigated using scanning electron microscope (SEM). SEM micrographs showed a decrease in size of spherulitic crystal structure of PVDF/RGO-ZnO nanocomposites compared with pure PVDF which has an obvious relation with β-phase enhancement. The thermal behaviors of PVDF/RGO-ZnO nanocomposite films have been investigated by employing thermogravimetric analysis (TGA). Since the interface between PVDF and the nanoparticles has an important role in the nucleation of the polymer phase, thermogravimetric analysis was used in order to identify and quantify the interface region and to correlate it with the β-phase content. It is found that an intimate relation exists between the size of the interface region and the piezoelectric β-phase formation that depends on the RGO-ZnO content. The interface value and the β-phase content increase with increasing RGO-ZnO. The PVDF nanocomposites showed higher thermal stability than the pure polymer.

  18. Thermally reduced kaolin-graphene oxide nanocomposites for gas sensing

    Science.gov (United States)

    Zhang, Renyun; Alecrim, Viviane; Hummelgård, Magnus; Andres, Britta; Forsberg, Sven; Andersson, Mattias; Olin, Håkan

    2015-01-01

    Highly sensitive graphene-based gas sensors can be made using large-area single layer graphene, but the cost of large-area pure graphene is high, making the simpler reduced graphene oxide (rGO) an attractive alternative. To use rGO for gas sensing, however, require a high active surface area and slightly different approach is needed. Here, we report on a simple method to produce kaolin-graphene oxide (GO) nanocomposites and an application of this nanocomposite as a gas sensor. The nanocomposite was made by binding the GO flakes to kaolin with the help of 3-Aminopropyltriethoxysilane (APTES). The GO flakes in the nanocomposite were contacting neighboring GO flakes as observed by electron microscopy. After thermal annealing, the nanocomposite become conductive as showed by sheet resistance measurements. Based on the conductance changes of the nanocomposite films, electrical gas sensing devices were made for detecting NH3 and HNO3. These devices had a higher sensitivity than thermally annealed multilayer GO films. This kaolin-GO nanocomposite might be useful in applications that require a low-cost material with large conductive surface area including the demonstrated gas sensors.

  19. Effect of oxidation degree on the synthesis and adsorption property of magnetite/graphene nanocomposites

    Science.gov (United States)

    Luo, Kun; Mu, Yuanying; Wang, Peng; Liu, Xiaoteng

    2015-12-01

    A facile approach is demonstrated to synthesize a series of magnetite/graphene nanocomposites by solvothermal method, which can be easily collected after removal of pollutants without secondary pollution of graphene powders. Raman and FT-IR analyses show that the reduction of the mixing vapor of ammonia and hydrazine at different reaction periods generates the discrepancy of oxidation degree for reduced graphene oxide (rGO), which can be kept after the solvothermal synthesis of Fe3O4/rGO nanocomposites. Batch adsorption experiments indicate that the nanocomposite with maximum oxidation degree of rGO presents the largest magnetization of 35.4 emu g-1 and adsorption capacity of 59.2 mg g-1 for Cu2+, while the one with minimum oxidation degree exhibits the strongest adsorption of 39.0 mg g-1 for methylene blue accompanied with appropriate magnetization of 9.0 emu g-1, and only 23% of initial capacity was lost after seven recycling use. The adsorption kinetics of the both composites follows the pseudo-second-order model, suggestive of physical and chemical interactions between the pollutants and adsorbent. The results suggest that the oxidation degree of the rGO substrate can apparently influence both the structure and the adsorbing behavior of Fe3O4/rGO nanocomposites, which allows the control over the adsorbent performance according to the pollutant of interest.

  20. Elastomeric Nanocomposite Based on Exfoliated Graphene Oxide and Its Characteristics without Vulcanization

    Directory of Open Access Journals (Sweden)

    Nasser Abdullah Habib

    2017-01-01

    Full Text Available Rubber nanocomposites have emerged as one of the advanced materials in recent years. The aim of this work was to homogeneously disperse graphene oxide (GO sheets into Nitrile Butadiene Rubber (NBR and investigate the characteristics of GO/NBR nanocomposite without vulcanization. A suitable solvent was found to dissolve dry NBR while GO was exfoliated completely in an aqueous base solution using sonication. GO was dispersed into NBR at different loadings by solution mixing to produce unvulcanized GO/NBR nanocomposites. Scanning Electron Microscopy (SEM, Fourier-Transform Infrared Spectroscopy (FTIR, and X-Ray Diffraction (XRD were used to characterize the samples. Furthermore, mechanical and electrical properties of unvulcanized GO/NBR nanocomposites were carried out to determine the influence of GO on the NBR properties. The results showed that the modulus of GO/NBR nanocomposite at 1 wt% of GO was enhanced by about 238% compared with unfilled NBR. These results provide insight into the properties of unvulcanized GO/NBR nanocomposite for application as coatings or adhesives.

  1. Conjugated polymer/graphene oxide nanocomposite as thermistor

    Energy Technology Data Exchange (ETDEWEB)

    Joshi, Girish M., E-mail: varadgm@gmail.com; Deshmukh, Kalim [Polymer Nanocomposite Laboratory, Material Physics Division, School of Advanced Sciences, VIT University, Vellore - 632014, TN (India)

    2015-06-24

    We demonstrated the synthesis and measurement of temperature dependent electrical resistivity of graphene oxide (GO) reinforced poly (3, 4 - ethylenedioxythiophene) - tetramethacrylate (PEDOTTMA)/Polymethylmethacrylate (PMMA) based nanocomposites. Negative temperature coefficient (NTC) was observed for 0.5, 1 % GO loading and the positive temperature coefficient (PTC) was observed for 1.5 and 2 % Go loading in the temperature (40 to 120 °C). The GO inducted nanocomposite perform as an excellent thermistor and suitable for electronic and sensor domain.

  2. Methyltrimethoxysilane (MTMS)-based silica-iron oxide superhydrophobic nanocomposites.

    Science.gov (United States)

    Nadargi, Digambar; Gurav, Jyoti; Marioni, Miguel A; Romer, Sara; Matam, Santhosh; Koebel, Matthias M

    2015-12-01

    We report a facile synthesis of superhydrophobic silica-iron oxide nanocomposites via a co-precursor sol-gel process. The choice of the silica precursor (Methyltrimethoxysilane, MTMS) in combination with iron nitrate altered the pore structure dramatically. The influence of iron oxide doping on the structural properties of pristine MTMS aerogel is discussed.

  3. Chitosan–silver oxide nanocomposite film: Preparation and antimicrobial activity

    Indian Academy of Sciences (India)

    Shipra Tripathi; G K Mehrotra; P K Dutta

    2011-02-01

    The chitosan–silver oxide encapsulated nanocomposite film was prepared by solution casting method. The prepared film was characterized by FTIR, scanning electron microscopy (SEM), thermal studies, and UV-Vis spectroscopy. The elemental composition of the film was studied by energy dispersive X-ray analysis (EDAX). The antibacterial activity of the composite film against pathogenic bacteria viz. Escherichia coli, Staphylococcus aureus, Bacillus subtilis and Pseudomonas aeruginosa was measured by agar diffusion method. Our observations suggest that chitosan as biomaterial based nanocomposite film containing silver oxide has an excellent antibacterial ability for food packaging applications.

  4. Evaluation of reduced graphene oxide/ZnO effect on properties of PVDF nanocomposite films

    Energy Technology Data Exchange (ETDEWEB)

    Jaleh, B., E-mail: jaleh@basu.ac.ir; Jabbari, A.

    2014-11-30

    Highlights: • Synthesis of reduced graphene oxide (RGO)/ZnO with three weight ratios (1:1, 2:1, 4:1). • Fabrication and characterization of PVDF/RGO-ZnO nanocomposite films. • The amount of 83% β-phase can be achieved by only addition of 1 wt% RGO-ZnO. • Enhancement of thermal stability in PVDF/RGO-ZnO (4:1) 1 wt% compare with pure PVDF. - Abstract: In this work, we report the preparation and characterization of PVDF/reduced graphene oxide (RGO)-ZnO nanocomposite films via synthesis of reduced graphene oxide-ZnO nanocomposite by solution casting method. Different weight ratios of RGO-ZnO nanocomposites were produced and compounded with PVDF by solution mixing. The compounding was followed by solution casting and drying to form nanocomposite films. Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction techniques (XRD), revealed an obvious α to β-phase transformation compared to pure PVDF which a maximum content of 83% for β-phase was calculated by using FTIR techniques. The morphology of the nanocomposites was investigated using scanning electron microscope (SEM). SEM micrographs showed a decrease in size of spherulitic crystal structure of PVDF/RGO-ZnO nanocomposites compared with pure PVDF which has an obvious relation with β-phase enhancement. The thermal behaviors of PVDF/RGO-ZnO nanocomposite films have been investigated by employing thermogravimetric analysis (TGA). Since the interface between PVDF and the nanoparticles has an important role in the nucleation of the polymer phase, thermogravimetric analysis was used in order to identify and quantify the interface region and to correlate it with the β-phase content. It is found that an intimate relation exists between the size of the interface region and the piezoelectric β-phase formation that depends on the RGO-ZnO content. The interface value and the β-phase content increase with increasing RGO-ZnO. The PVDF nanocomposites showed higher thermal stability than the pure polymer.

  5. Graphene oxide-silica nanohybrids as fillers for PA6 based nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Maio, A. [Department of Civil, Environmental, Aerospace, Materials Engineering, University of Palermo, Viale delle Scienze, Ed. 6, 90128, Palermo, Italy and STEBICEF, Section of Biology and Chemistry, University of Palermo, Viale delle Scienze, Parco d' Orleans (Italy); Fucarino, R.; Khatibi, R. [Dipartimento di Ingegneria Chimica, Gestionale, Informatica, Meccanica, University of Palermo, Viale delle Scienze, Ed. 6, 90128, Palermo (Italy); Botta, L.; Scaffaro, R. [Department of Civil, Environmental, Aerospace, Materials Engineering, University of Palermo, Viale delle Scienze, Ed. 6, 90128, Palermo (Italy); Rosselli, S.; Bruno, M. [STEBICEF, Section of Biology and Chemistry, University of Palermo, Viale delle Scienze, Parco d' Orleans II, 90128 Palermo (Italy)

    2014-05-15

    Graphene oxide (GO) was prepared by oxidation of graphite flakes by a mixture of H{sub 2}SO{sub 4}/H{sub 3}PO{sub 4} and KMnO{sub 4} based on Marcano's method. Two different masterbatches containing GO (33.3%) and polyamide-6 (PA6) (66.7%) were prepared both via solvent casting in formic acid and by melt mixing in a mini-extruder (Haake). The two masterbatches were then used to prepare PA6-based nanocomposites with a content of 2% in GO. For comparison, a nanocomposite by direct mixing of PA6 and GO (2%) and PA6/graphite nanocomposites were prepared, too. The oxidation of graphite into GO was assessed by X-ray diffraction (XRD), Micro-Raman spectroscopy, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) analyses. All these techniques demonstrated the effectiveness of the graphite modification, since the results put into evidence that, after the acid treatment, interlayer distance, oxygen content and defects increased. SEM micrographs carried out on the nanocomposites, showed GO layers totally surrounded by polyamide-6, this feature is likely due to the strong interaction between the hydrophilic moieties located both on GO and on PA6. On the contrary, no interactions were observed when graphite was used as filler. Mechanical characterization, carried out by tensile and dynamic-mechanical tests, marked an improvement of the mechanical properties observed. Photoluminescence and EPR measurements were carried out onto nanoparticles and nanocomposites to study the nature of the interactions and to assess the possibility to use this class of materials as semiconductors or optical sensors.

  6. Effect of Nanodiamonds on Structure and Durability of Polyethylene Oxide-Based Nanocomposites

    Directory of Open Access Journals (Sweden)

    Rossella Arrigo

    2016-01-01

    Full Text Available Polymer-based nanocomposites containing nanodiamonds (NDs are attractive multifunctional materials with a growing range of applications. In this work, in the frame of developing completely biocompatible systems, nanocomposites based on polyethylene oxide (PEO and different amount of NDs have been formulated through melt mixing and fully characterized. In particular, the reinforcement effect of NDs in PEO has been probed through tensile tests, and the rheological response of PEO-based nanocomposites as a function of the nanoparticles amount has been investigated and discussed. The obtained results show that the presence of well-distributed NDs strengthens the mechanical performance of the nanocomposites and brings about an increase of the PEO crystallinity, suggesting a strong adhesion between NDs and polymer matrix. Furthermore, as a result of NDs adding, alterations of the rheological behaviour of neat PEO can be noticed, as NDs are able to significantly influence the long-range dynamics of PEO chains. Besides, accelerated aging tests demonstrate that NDs show a remarkable protective ability against PEO photodegradation, due to their ability to attenuate efficiently UV radiation. The latter opens up new avenues for the use of NDs as multifunctional nanofillers for polymer-based nanocomposites with enhanced photooxidative resistance.

  7. Synthesis and characterisation: Zinc oxide-sulfide nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Verma, Prinsa, E-mail: prinsa.verma@gmail.co [Nanophosphor Application Center, Allahabad University (India); Satish Dhawan Space Center, ISRO (India); Pandey, Avinash C. [Nanophosphor Application Center, Allahabad University (India); Bhargava, R.N. [Nanocrystal Technology, New York (United States)

    2009-11-15

    A novel synthesis method is presented for the preparation of nanosized-semiconductor zinc oxide-sulphide (ZnO/ZnS) core-shell nanocomposites, both formed sequentially from a single-source solid precursor. ZnO nanocrystals were synthesized by a simple co-precipitation method and ZnO/ZnS core-shell nanocomposites were successfully fabricated by sulfidation of ZnO nanocrystals via a facile chemical synthesis at room temperature. The as-obtained samples were characterized by X-ray diffraction and transmission electron microscopy. The results showed that the pure ZnO nanocrystals were hexagonal wurtzite crystal structures and the ZnS nanoparticles were sphalerite structure with the size of about 10 nm grown on the surface of the ZnO nanocrystals. Optical properties measured reveal that ZnO/ZnS core-shell nanocomposites have integrated the photoluminescent effect of ZnO and ZnS. Based on the results of the experiments, a possible formation mechanism of ZnO/ZnS core-shell nanocomposites was also suggested. This treatment is suggested to improve various properties of optoelectronically valuable ZnO/ZnS nanocomposites. These nanosized semiconductor nanocomposites can form a new class of luminescent materials for various applications.

  8. ZnO nanowire/reduced graphene oxide nanocomposites for significantly enhanced photocatalytic degradation of Rhodamine 6G

    Science.gov (United States)

    Zhang, Chao; Zhang, Jing; Su, Yanjie; Xu, Minghan; Yang, Zhi; Zhang, Yafei

    2014-02-01

    We have demonstrated a facile and low-cost approach to synthesize ZnO nanowire (NW)/reduced graphene oxide (RGO) nanocomposites, in which ZnO NWs and graphene oxide (GO) were produced in large scale separately and then hybridized into ZnO NW/RGO nanocomposites by mechanical mixing and low-temperature thermal reduction. Rhodamine 6G (Rh6G) was used as a model dye to evaluate the photocatalytic properties of ZnO NW/RGO nanocomposites. The obtained nanocomposites show significantly enhanced photocatalytic performance, which took only 10 min to decompose over 98% Rh6G. Finally the mechanism of the great enhancement about photocatalytic activity of ZnO NW/RGO nanocomposites is studied. It is mainly attributed to that RGO nanosheets can transfer the electrons of ZnO NWs excited by ultraviolet (UV) irradiation, increase electron migration efficiency, and then longer the lifetime of the holes in ZnO NWs. The high charge separation efficiency of photo-generated electron-hole pairs directly leads to the lower recombination rate of ZnO NW/RGO nanocomposites, makes more effective electrons and holes to participate the radical reactions with Rh6G, thus significantly improving the photocatalytic properties. The high degradation efficiency makes the ZnO NW/RGO nanocomposites promising candidates in the application of environmental pollutant and wastewater treatment.

  9. Electrodeposition of Polypyrrole/Reduced Graphene Oxide/Iron Oxide Nanocomposite as Supercapacitor Electrode Material

    Directory of Open Access Journals (Sweden)

    Y. C. Eeu

    2013-01-01

    Full Text Available Polypyrrole (PPy was reinforced with reduced graphene oxide (RGO and iron oxide to achieve electrochemical stability and enhancement. The ternary nanocomposite film was prepared using a facile one-pot chronoamperometry approach, which is inexpensive and experimentally friendly. The field emission scanning electron microscopy (FESEM image shows a layered morphology of the ternary nanocomposite film as opposed to the dendritic structure of PPy, suggesting hybridization of the three materials during electrodeposition. X-ray diffraction (XRD profile shows the presence of Fe2O3 in the ternary nanocomposite. Cyclic voltammetry (CV analysis illustrates enhanced current for the nanocomposite by twofold and fourfold compared to its binary (PPy/RGO and individual (PPy counterparts, respectively. The ternary nanocomposite film exhibited excellent specific capacitance retention even after 200 cycles of charge/discharge.

  10. Biosensor based on Prussian blue nanocubes/reduced graphene oxide nanocomposite for detection of organophosphorus pesticides

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Lin; Zhang, Aidong; Du, Dan; Lin, Yuehe

    2012-07-13

    We demonstrate a facile procedure to efficiently prepare Prussian blue nanocubes/reduced graphene oxide (PBNCs/rGO) nanocomposite by directly mixing Fe3+ and [Fe(CN)6]3 in the presence of GO in polyethyleneimine aqueous solution, resulting in a novel acetylcholinesterase (AChE) biosensor for detection of organophosphorus pesticides (OPs). The obtained nanocomposite was characterized by X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and energy dispersive X-ray (EDX) microanalysis. It was clearly observed that the nanosheet has been decorated with cubic PB nanoparticles and nearly all the nanoparticles are distributed uniformly only on the surface of the reduced GO. No isolated PB nanoparticles were observed, indicating the strong interaction between PB nanocubes and the reduced GO and the formation of PBNCs/rGO nanocomposite. The obtained PBNCs/rGO based AChE biosensor make the peak potential shift negatively to 220 mV. The AChE biosensor shows rapid response and high sensitivity for detection of monocrotophos. These results suggest that the PBNCs/rGO hybrids nanocomposite exhibited high electrocatalytic activity towards the oxidation of thiocholine, which lead to the sensitive detection of OP pesticides.

  11. Nickel Oxide/Carbon Nanotubes Nanocomposite for Electrochemical Capacitance

    Institute of Scientific and Technical Information of China (English)

    Kui LIANG; Kayhyeok AN; Younghee LEE

    2005-01-01

    A nanocomposite of nickel oxide/carbon nanotubes was prepared through a simple chemical precipitation followed by thermal annealing. The electrochemical capacitance of this electrode material was studied. When the mass fraction of CNTs (carbon nanotubes) in NiO/CNT composites increases, the electrical resistivity of nanocomposites decreases and becomes similar to that of pure CNTs when it reaches 30%. The specific surface area of composites increases with increasing CNT mass fraction and the specific capacitance reaches 160 F/g under 10 mA/g discharge current density at CNT mass fraction of 10%.

  12. Study of nanocomposites based on iron oxides and pectin

    Energy Technology Data Exchange (ETDEWEB)

    Chistyakova, Nataliya I., E-mail: nchistyakova@yandex.ru; Shapkin, Alexey A., E-mail: nchistyakova@yandex.ru; Sirazhdinov, Ruslan R., E-mail: nchistyakova@yandex.ru; Gubaidulina, Tatiana V., E-mail: nchistyakova@yandex.ru; Kiseleva, Tatiana Yu., E-mail: nchistyakova@yandex.ru; Kazakov, Alexander P., E-mail: nchistyakova@yandex.ru; Rusakov, Vyacheslav S., E-mail: nchistyakova@yandex.ru [M. V. Lomonosov Moscow State University, Faculty of Physics, Leninskie gory, 119991 Moscow (Russian Federation)

    2014-10-27

    Mössbauer and X-ray diffraction study of nanocomposites based on iron oxides and pectin (PC) was carried out involving magnetization measurements. The concentrations of PC in nanocomposites varied from 0 to 10%. Mössbauer investigations of nanocomposites were carried out in the temperature range from 5 to 300 K. Many-state superparamagnetic relaxation model was used for spectra fitting. The magnetization, M(T,H), was measured in the temperature interval of 80-300 K and magnetic field up to 10 kOe. Formation of the 'iron-polymer' interface was not observed. Particle sizes were estimated using the Mössbauer and X-ray powder diffraction data.

  13. Study of nanocomposites based on iron oxides and pectin

    Science.gov (United States)

    Chistyakova, Nataliya I.; Shapkin, Alexey A.; Sirazhdinov, Ruslan R.; Gubaidulina, Tatiana V.; Kiseleva, Tatiana Yu.; Kazakov, Alexander P.; Rusakov, Vyacheslav S.

    2014-10-01

    Mössbauer and X-ray diffraction study of nanocomposites based on iron oxides and pectin (PC) was carried out involving magnetization measurements. The concentrations of PC in nanocomposites varied from 0 to 10%. Mössbauer investigations of nanocomposites were carried out in the temperature range from 5 to 300 K. Many-state superparamagnetic relaxation model was used for spectra fitting. The magnetization, M(T,H), was measured in the temperature interval of 80-300 K and magnetic field up to 10 kOe. Formation of the "iron-polymer" interface was not observed. Particle sizes were estimated using the Mössbauer and X-ray powder diffraction data.

  14. Highly active Ce 1- xCu xO 2 nanocomposite catalysts for the low temperature oxidation of CO

    Science.gov (United States)

    Mai, Hailing; Zhang, Dengsong; Shi, Liyi; Yan, Tingting; Li, Hongrui

    2011-06-01

    A series of Ce 1- xCu xO 2 nanocomposite catalysts with various copper contents were synthesized by a simple hydrothermal method at low temperature without any surfactants, using mixed solutions of Cu(II) and Ce(III) nitrates as metal sources. These bimetal oxide nanocomposites were characterized by means of XRD, TEM, HRTEM, EDS, N 2 adsorption, H 2-TPR and XPS. The influence of Cu loading (5-25 mol%) and calcination temperature on the surface area, particle size and catalytic behavior of the nanocomposites have been discussed. The catalytic activity of Ce 1- xCu xO 2 nanocomposites was investigated using the test of CO oxidation reaction. The optimized performance was achieved for the Ce 0.80Cu 0.20O 2 nanocomposite catalyst, which exhibited superior reaction rate of 11.2 × 10 -4 mmol g -1 s -1 and high turnover frequency of 7.53 × 10 -2 s -1 (1% CO balanced with air at a rate of 40 mL min -1, at 90 °C). No obvious deactivation was observed after six times of catalytic reactions for Ce 0.80Cu 0.20O 2 nanocomposite catalyst.

  15. Chitosan-Iron Oxide Coated Graphene Oxide Nanocomposite Hydrogel: A Robust and Soft Antimicrobial Biofilm.

    Science.gov (United States)

    Konwar, Achyut; Kalita, Sanjeeb; Kotoky, Jibon; Chowdhury, Devasish

    2016-08-17

    We report a robust biofilm with antimicrobial properties fabricated from chitosan-iron oxide coated graphene oxide nanocomposite hydrogel. For the first time, the coprecipitation method was used for the successful synthesis of iron oxide coated graphene oxide (GIO) nanomaterial. After this, films were fabricated by the gel-casting technique aided by the self-healing ability of the chitosan hydrogel network system. Both the nanomaterial and the nanocomposite films were characterized by techniques such as scanning electron microscopy, FT-IR spectroscopy, X-ray diffraction, and vibrating sample magnetometry. Measurements of the thermodynamic stability and mechanical properties of the films indictaed a significant improvement in their thermal and mechanical properties. Moreover, the stress-strain profile indicated the tough nature of the nanocomposite hydrogel films. These improvements, therefore, indicated an effective interaction and good compatibility of the GIO nanomaterial with the chitosan hydrogel matrix. In addition, it was also possible to fabricate films with tunable surface properties such as hydrophobicity simply by varying the loading percentage of GIO nanomaterial in the hydrogel matrix. Fascinatingly, the chitosan-iron oxide coated graphene oxide nanocomposite hydrogel films displayed significant antimicrobial activities against both Gram-positive and Gram-negative bacterial strains, such as methicillin-resistant Staphylococcus aureus, Staphylococcus aureus, and Escherichia coli, and also against the opportunistic dermatophyte Candida albicans. The antimicrobial activities of the films were tested by agar diffusion assay and antimicrobial testing based on direct contact. A comparison of the antimicrobial activity of the chitosan-GIO nanocomposite hydrogel films with those of individual chitosan-graphene oxide and chitosan-iron oxide nanocomposite films demonstrated a higher antimicrobial activity for the former in both types of tests. In vitro hemolysis

  16. Polymer/Transitonal Metal Oxides Nanocomposites as Cathode Materials for Rechargeable Lithium/Lithium lon Batteries

    Institute of Scientific and Technical Information of China (English)

    Hui Kang Wu

    2000-01-01

    The synthesis and properties of polymer/transition metal oxides nanocomposite material were reviewed.The new nanocomposite material(PPY)0.5/MoO3 prepared by a new method is described.The application of the nanocomposite materials as cathode material in rechargeable lithium/lithium ion batteries was explored.

  17. Fabrication of ammonium perchlorate/copper-chromium oxides core-shell nanocomposites for catalytic thermal decomposition of ammonium perchlorate

    Energy Technology Data Exchange (ETDEWEB)

    Eslami, Abbas, E-mail: eslami@umz.ac.ir [Department of Inorganic Chemistry, Faculty of Chemistry, University of Mazandaran, P.O.Box 47416-95447, Babolsar (Iran, Islamic Republic of); Juibari, Nafise Modanlou [Department of Inorganic Chemistry, Faculty of Chemistry, University of Mazandaran, P.O.Box 47416-95447, Babolsar (Iran, Islamic Republic of); Hosseini, Seyed Ghorban [Department of Chemistry, Malek Ashtar University of Technology, P.O. Box 16765-3454, Tehran (Iran, Islamic Republic of)

    2016-09-15

    The ammonium perchlorate/Cu(II)-Cr(III)-oxides(AP/Cu-Cr-O) core-shell nanocomposites were in-situ prepared by deposition of copper and chromium oxides on suspended ammonium perchlorate particles in ethyl acetate as solvent. The results of differential scanning calorimetery (DSC) and thermal gravimetric analysis (TGA) experiments showed that the nanocomposites have excellent catalytic effect on the thermal decomposition of AP, so that the released heat increases up to about 3-fold over initial values, changing from 450 J/g for pure AP to 1510 J/g for most appropriate mixture. For better comparison, single metal oxide/AP core-shell nanocomposite have also been prepared and the results showed that they have less catalytic effect respect to mixed metal oxides system. Scanning electron microscopy (SEM) results revealed homogenous deposition of nanoparticles on the surface of AP and fabrication of core-shell structures. The kinetic parameters of thermal decomposition of both pure AP and AP/Cu-Cr-O samples have been calculated by Kissinger method and the results showed that the values of pre-exponential factor and activation energy are higher for AP/Cu-Cr-O nanocomposite. The better catalytic effect of Cu-Cr-O nanocomposites is probably attributed to the synergistic effect between Cu{sup 2+} and Cr{sup 3+} in the nanocomposites, smaller particle size and more crystal defect. - Highlights: • The Cu-Cr-O nanoparticles were synthesized by chemical liquid deposition method. • Then, the AP/Cu-Cr-O core-shell nanocomposites were prepared. • The core-shell samples showed high catalytic activity for AP decomposition. • Thermal decomposition of samples occurs at lower temperature range.

  18. Metal Oxide-Carbon Nanocomposites for Aqueous and Nonaqueous Supercapacitors Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This Small Business Innovation Research Phase I effort focuses on development of novel metal-oxide-carbon nanocomposites for application in pseudocapacitive...

  19. Optical waveguides using PDMS-metal oxide hybrid nanocomposites

    Science.gov (United States)

    Hosseinzadeh, Arash; Middlebrook, Christopher T.; Mullins, Michael E.

    2015-03-01

    Development of passive and active polymer based optical materials for high data rate waveguide routing and interconnects has gained increased attention because of their excellent properties such as low absorption, cost savings, and ease in fabrication. However, optical polymers are typically limited in the range of their refraction indices. Combining polymeric and inorganic optical materials provides advantages for as development of nano-composites with higher refractive indices with the possibility of being used as an active optical component. In this paper a new composite material is proposed based on polymer-metal oxide nano-composites for use as optical wave guiding structures and components. PDMS (Polydimethylsiloxane) is utilized for the polymer portion while the inorganic material is titanium dioxide. Refraction indices as high as 1.74 have been reported using these composites. For PDMS-TiO2 hybrids, the higher the ratio of titanium dioxide to PDMS, the higher the resulting refractive index. The index of refraction as a function of the PDMS:TiO2 ratio is reported with an emphasis on use as optical waveguide devices. Absorption spectrum of the nano-composites is measured showing low absorption at 850 nm and high absorption in the UV regime for direct UV laser/light curing. Prototype multimode waveguides are fabricated using soft imprint embossing that is compatible with the low viscosity nano-composite material. Cross dimensional shape and profile show the potential for full scale development utilizing the material set.

  20. Synthesis and characterization of fly ash-zinc oxide nanocomposite

    Directory of Open Access Journals (Sweden)

    Kunal Yeole

    2014-04-01

    Full Text Available Fly ash, generated in thermal power plants, is recognized as an environmental pollutant. Thus, measures are required to be undertaken to dispose it in an environmentally friendly method. In this paper an attempt is made to coat zinc oxide nano-particles on the surface of fly ash by a simple and environmentally friendly facile chemical method, at room temperature. Zinc oxide may serve as effective corrosion inhibitor by providing sacrificial protection. Concentration of fly ash was varied as 5, 10 and 15 (w/w % of zinc oxide. It was found that crystallinity increased, whereas particle size, specific gravity and oil absorption value decreased with increased concentration of fly ash in zinc oxide, which is attributed to the uniform distribution of zinc oxide on the surface of fly ash. These nanocomposites can potentially be used in commercial applications as additive for anticorrosion coatings.

  1. Synthesis and sintering of ceramic nanocomposites with high mixed conductivity

    Directory of Open Access Journals (Sweden)

    Zyryanov V.V.

    2005-01-01

    Full Text Available Metastable solid solutions of complex oxides with fluorite and perovskite structures are obtained by mechanosynthesis. Dense ceramics on the base of these metastable phases was obtained by thermal sintering of nanopowders due to kinetic stabilization. Different degrees of a chemical interaction (interdiffusion are observed during sintering of "perovskite+fluorite" and "perovskite+perovskite" composites. It is shown, that optimization of the composition, mixing conditions of individual phases and their sintering, preparation of ceramic composites with mixed conductivity for use in catalytic membrane reactors is possible. Unusual behavior of complex perovskites and fluorites is discovered during sintering, enabling determination of an optimum sintering temperature and time for which a qualitative explanation is given. It is established that rearrangement of fine crystalline particles as a whole plays a key role in shrinkage.

  2. Optimized Quality Factor of Graphene Oxide-Reinforced PVC Nanocomposite

    Science.gov (United States)

    Joshi, Girish M.; Deshmukh, Kalim

    2014-04-01

    Graphene oxide (GO)-reinforced polyvinyl chloride (PVC) composite films were prepared by solution blending. The homogeneity of GO dispersion with PVC was confirmed by an optical microscope. Quality factor ( Q-factor) as a function of temperature (40-150 °C) was measured within a broadband frequency range of 50-35 MHz. The controlled GO loading demonstrates a crucial impact on the optimization of the Q-factor, resonance frequency ( f 0) and wide bandwidth. This nanocomposite may be well suited for electronic applications. The further development of GO-reinforced polymer nanocomposites based on an optimized Q-factor may result in a material for electromagnetic frequency radiation shields for radar and communication towers/devices.

  3. DISPERSION OF GRAPHENE OXIDE AND ITS FLAME RETARDANCY EFFECT ON EPOXY NANOCOMPOSITES

    Institute of Scientific and Technical Information of China (English)

    Zhou Wang; Xiu-zhi Tang; Zhong-zhen Yu; Peng Guo; Huai-he Song; Xu-sheng Du

    2011-01-01

    Grraphene oxide was prepared by ultrasonication of completely oxidized graphite and used to improve the flame retardancy of epoxy. The epoxy/graphene oxide nanocomposite was studied in terms of exfoliation/dispersion, thermal stability and flame retardancy. X-ray diffraction and transmission electron microscopy confirmed the exfoliation of the graphene oxide nanosheets in epoxy matrix. Cone calorimeter measurements showed that the time to ignition of the epoxy/graphene oxide nanocomposite was longer than that of neat epoxy. The heat release rate curve of the nanocomposite was broadened compared to that of neat epoxy and the peak heat release rate decreased as well.

  4. Graphene oxide-MnO2 nanocomposite for supercapacitor application

    Science.gov (United States)

    Muhammed Shafi, P.; Vishal, Jose K.; Chandra Bose, A.

    2016-09-01

    Increased depletion of fossil fuels along with global warming and climate change made the society to think about alternate green and sustainable energy sources and better energy storage devices. Extensive research has been performed on the development of solar cells, fuel cells, Lithium- ion battery and supercapacitors to combat the green house effect and its consequences, and to meet the increased energy crisis. Supercapacitors, also known as electrochemical capacitors are gained a great attention because of their pulse power supply, long cycle life (>100,000), simple principle and high dynamic of charge propagation. Its greater power density than lithium- ion battery and much larger energy density than conventional capacitors brought super capacitors to a promising energy storage device to meet the increased energy demands. Here we demonstrate supercapacitor electrode materials with graphene oxide (electric double layer capacitor) and α-MnO2 nanomaterial (pseudo-capacitor), as well as composite of these materials, which means that the bulk of the material undergoes a fast redox reaction to provide the capacitive response and they exhibit superior specific energies in addition to the carbon-based supercapacitors (double-layer capacitors). A simple soft chemical route is utilized to synthesize graphene oxide, α-MnO2 and graphene oxide-MnO2 composite. The phase and the structure of the synthesized materials are studied using X-ray diffractometry (XRD). The functional group and the presence of impurities are understood from Fourier transform infrared (FTIR) spectra. The capacitive properties of the graphene oxide, graphene oxide - MnO2 nanocomposite and α-MnO2 are tested with the help of cyclic voltammetry (CV) and galvanostatic charge - discharge techniques using 1 M Na2SO4 in aqueous solution as electrolyte. It was found that graphene oxide - MnO2 nanocomposite shows better electrochemical behaviour compared to individual graphene oxide and α-MnO2 nanomaterial.

  5. Biopolymer-modified graphite oxide nanocomposite films based on benzalkonium chloride-heparin intercalated in graphite oxide

    Energy Technology Data Exchange (ETDEWEB)

    Meng Na; Zhou Ninglin; Shen Jian [Jiangsu Engineering Research Center for Biomedical Function Materials, Nanjing Normal University, Nanjing 210046 (China); Zhang Shuangquan, E-mail: zhouninglin@njnu.edu.cn, E-mail: jshen@njnu.edu.cn, E-mail: shuangquanz@yahoo.com [Jiangsu Province Key Laboratory for Molecular and Medical Biotechnology, Life Sciences College, Nanjing Normal University, Nanjing 210046 (China)

    2010-05-07

    Heparin is a potent anticoagulant agent that interacts strongly with antithrombin III to prevent the formation of fibrin clots. In the present work, poly(dimethylsiloxane)(PDMS)/graphite oxide-benzalkonium chloride-heparin (PDMS/modified graphite oxide) nanocomposite films were obtained by the solution intercalation technique as a possible drug delivery system. The heparin-benzalkonium chloride (BAC-HEP) was intercalated into graphite oxide (GO) layers to form GO-BAC-HEP (modified graphite oxide). Nanocomposite films were characterized by XRD, SEM, TEM, ATR-FTIR and TGA. The modified graphite oxide was observed to be homogeneously dispersed throughout the PDMS matrix. The effect of modified graphite oxide on the mechanical properties of the nanocomposite film was investigated. When the modified graphite oxide content was lower than 0.2 wt%, the nanocomposites showed excellent mechanical properties. Furthermore, nanocomposite films become delivery systems that release heparin slowly to make the nanocomposite films blood compatible. The in vitro studies included hemocompatibility testing for effects on platelet adhesion, platelet activation, plasma recalcification profiles, and hemolysis. Results from these studies showed that the anticoagulation properties of PDMS/GO-BCA-HEP nanocomposite films were greatly superior to those for no treated PDMS. Cell culture assay indicated that PDMS/GO-BCA-HEP nanocomposite films showed enhanced cell adhesion.

  6. Biopolymer-modified graphite oxide nanocomposite films based on benzalkonium chloride-heparin intercalated in graphite oxide

    Science.gov (United States)

    Meng, Na; Zhang, Shuang-Quan; Zhou, Ning-Lin; Shen, Jian

    2010-05-01

    Heparin is a potent anticoagulant agent that interacts strongly with antithrombin III to prevent the formation of fibrin clots. In the present work, poly(dimethylsiloxane)(PDMS)/graphite oxide-benzalkonium chloride-heparin (PDMS/modified graphite oxide) nanocomposite films were obtained by the solution intercalation technique as a possible drug delivery system. The heparin-benzalkonium chloride (BAC-HEP) was intercalated into graphite oxide (GO) layers to form GO-BAC-HEP (modified graphite oxide). Nanocomposite films were characterized by XRD, SEM, TEM, ATR-FTIR and TGA. The modified graphite oxide was observed to be homogeneously dispersed throughout the PDMS matrix. The effect of modified graphite oxide on the mechanical properties of the nanocomposite film was investigated. When the modified graphite oxide content was lower than 0.2 wt%, the nanocomposites showed excellent mechanical properties. Furthermore, nanocomposite films become delivery systems that release heparin slowly to make the nanocomposite films blood compatible. The in vitro studies included hemocompatibility testing for effects on platelet adhesion, platelet activation, plasma recalcification profiles, and hemolysis. Results from these studies showed that the anticoagulation properties of PDMS/GO-BCA-HEP nanocomposite films were greatly superior to those for no treated PDMS. Cell culture assay indicated that PDMS/GO-BCA-HEP nanocomposite films showed enhanced cell adhesion.

  7. Microwave sintered nanocomposite electrodes for solid oxide fuel cells.

    Science.gov (United States)

    Raza, Rizwan; Zhu, Bin

    2011-06-01

    Microwave sintering is a very interesting subject, which provides an alternative method to overcome problems faced with conventional sintering. This process is very efficient and only requires a few minutes. In this paper, nanocomposite electrodes (Cu0.15Ni0.85-GDC) were sintered at 700 degrees C for 10 mins in a single mode 2.45 GHz microwave oven by the solid state reaction method. The composition influence and the sintering methods on the as-obtained powder were characterized by XRD, SEM and TEM. It was observed that excellent sintering took place. Excellent fuel cell performance was achieved with microwave sintering compared tosamples sintered using conventional sintering. Electrochemical analysis was carried out using AC Impedance technique. This paper reports a new approach to develop a microwave sintered based nanocomposite material, which is more efficient on time and energy. This method can gain significant economical benefits compared to conventional sintered materials for applications in low temperature solid oxide fuel cells (LTSOFC).

  8. Osteogenic activity and antibacterial effect of zinc oxide/carboxylated graphene oxide nanocomposites: Preparation and in vitro evaluation.

    Science.gov (United States)

    Chen, Junyu; Zhang, Xin; Cai, He; Chen, Zhiqiang; Wang, Tong; Jia, Lingling; Wang, Jian; Wan, Qianbing; Pei, Xibo

    2016-11-01

    The aim of this study was to prepare nanocomposites of carboxylated graphene oxide (GO-COOH) sheets decorated with zinc oxide (ZnO) nanoparticles (NPs) and investigate their advantages in the field of bone tissue engineering. First, ZnO/GO-COOH nanocomposites were synthesized by facile reactions, including the carboxylation of graphene oxide (GO) and the nucleation of ZnO on GO-COOH sheets. The synthesized ZnO/GO-COOH nanocomposites were then characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectra, and transmission electron microscopy (TEM). The biocompatibility, osteogenic activity and antibacterial effect of ZnO/GO-COOH nanocomposites were further investigated. In the nanocomposites, ZnO nanoparticles with a size of approximately 12nm were uniformly decorated on GO-COOH sheets. Compared with GO-COOH and the control group, ZnO/GO-COOH nanocomposites significantly enhanced ALP activity, osteocalcin production and extracellular matrix mineralization as well as up-regulated osteogenic-related genes (ALP, OCN, and Runx2) in MG63 osteoblast-like cells. Moreover, ZnO/GO-COOH nanocomposites had an antibacterial effect against Streptococcus mutans. These results indicated that ZnO/GO-COOH nanocomposites exhibited both osteogenic activity and antibacterial effect and had great potential for designing new biomaterials in the field of bone tissue engineering.

  9. Preparation of uniform mixed metal oxide and superconductive oxides

    Energy Technology Data Exchange (ETDEWEB)

    Barder, T.J.

    1991-04-30

    This paper describes a method for producing a uniform mixed metal oxide. It includes dissolving metals as their salts of a carboxylic acid in an aliphatic alcohol in the substantial absence of water, the metals are in the same proportions as in the corresponding mixed metal oxide; co-precipitating the metals as their oxalates by mixing the alcohol solution with oxalic acid; separating the co-precipitated metal oxalates and calcining the oxalates in air or oxygen above about 500{degrees} C to convert the oxalates to the corresponding metal oxides.

  10. On the electrical arc interruption by using PMMA/iron oxide nanocomposites

    Science.gov (United States)

    Doddapaneni, Venkatesh; Saleemi, Mohsin; Ye, Fei; Gati, Rudolf; Toprak, Muhammet S.

    2016-10-01

    An experimental study is undertaken on the fabrication of poly (methyl methacrylate) (PMMA)/iron oxide nanocomposites to determine their potential use for electrical arc interruption in the electrical switching applications such as circuit breakers. Monodisperse iron oxide nanoparticles of average size ∼11 nm are synthesized via thermal decomposition method and then homogeneously dispersed in the PMMA matrix by in situ polymerization. PMMA/iron oxide nanocomposites with different nanoparticle loading have been fabricated to study the effect of loading content on the thermal energy absorption. Detailed physicochemical characterizations on synthesized material are performed using x-ray powder diffraction, scanning electron microscopy, TEM, thermogravimetric analysis and differential scanning calorimetry at different processing stages. A test-setup was designed to evaluate the quality of the nanocomposites for electric arc interruption capability. The results showed that PMMA/iron oxide nanocomposites have a clear impact on the electric arc interruption and therefore should be considered as promising candidates for electrical switching applications.

  11. Carbon nanotube/nickel oxide nanocomposite thin films for selective solar absorber

    CSIR Research Space (South Africa)

    Roro, Kittessa T

    2010-09-01

    Full Text Available Multi-walled carbon nanotube (MWCNT)/Nickel oxide nanocomposites were prepared on aluminum substrates for selective solar absorber applications. MWCNTs are functionalized in order to disperse in water and ethanol. Results from the characterization...

  12. Tunable room-temperature ferromagnet using an iron-oxide and graphene oxide nanocomposite

    KAUST Repository

    Lin, Aigu L.

    2015-06-23

    Magnetic materials have found wide application ranging from electronics and memories to medicine. Essential to these advances is the control of the magnetic order. To date, most room-temperature applications have a fixed magnetic moment whose orientation is manipulated for functionality. Here we demonstrate an iron-oxide and graphene oxide nanocomposite based device that acts as a tunable ferromagnet at room temperature. Not only can we tune its transition temperature in a wide range of temperatures around room temperature, but the magnetization can also be tuned from zero to 0.011 A m2/kg through an initialization process with two readily accessible knobs (magnetic field and electric current), after which the system retains its magnetic properties semi-permanently until the next initialization process. We construct a theoretical model to illustrate that this tunability originates from an indirect exchange interaction mediated by spin-imbalanced electrons inside the nanocomposite. © 2015 Scientific Reports.

  13. Mesoporous binary metal oxide nanocomposites: Synthesis, characterization and decontamination of sulfur mustard

    Energy Technology Data Exchange (ETDEWEB)

    Praveen Kumar, J., E-mail: praveenjella10@gmail.com; Prasad, G.K.; Ramacharyulu, P.V.R.K.; Singh, Beer; Gopi, T.; Krishna, R.

    2016-04-15

    Mesoporous MnO{sub 2}–ZnO, Fe{sub 2}O{sub 3}–ZnO, NiO–ZnO, and CeO{sub 2}–ZnO binary metal oxide nanocomposites were studied as sorbent decontaminants against sulfur mustard. They were synthesized by precipitation pyrolysis method and characterized by means of transmission electron microscopy, scanning electron microscopy coupled with energy dispersive analysis of X rays, X ray diffraction, and nitrogen adsorption techniques. The transmission electron microscopy and nitrogen adsorption data indicated the presence of pores with diameter ranging from 10 to 70 nm in the binary metal oxide nanocomposites and these materials exhibited surface area values in the range of 76–134 m{sup 2}/g. These binary metal oxide nanocomposites demonstrated large decontamination efficiencies against sulfur mustard when compared to their single component metal oxide nanoparticles. The binary metal oxide nanocomposites effectively decontaminated sulfur mustard into relatively non toxic products such as chloro ethyl vinyl sulfide, divinyl sulfide, 1,4-oxathiane, etc. The promising decontamination properties of binary metal oxide nanocomposites against sulfur mustard were attributed to the basic sites, Lewis acid sites, and the presence of these sites was confirmed by CO{sub 2} and NH{sub 3} temperature programmed desorption. - Graphical abstract: Mesoporous MnO{sub 2}–ZnO, Fe{sub 2}O{sub 3}–ZnO, NiO–ZnO, and CeO{sub 2}–ZnO binary metal oxide nanocomposites were studied as sorbent decontaminants against sulfur mustard. - Highlights: • Binary metal oxide nanocomposites were synthesized by co-precipitation method. • They were studied as sorbent decontaminants against sulfur mustard. • They decontaminated sulfur mustard into non toxic products. • MnO{sub 2}–ZnO and CeO{sub 2}–ZnO nanocomposites showed greater decontamination efficiency.

  14. Correlating crystallization and ionic conductivity of PEO/graphene oxide nanocomposite

    Science.gov (United States)

    Cheng, Shan; Smith, Derrick; Hsuan, Grace; Li, Christopher

    2012-02-01

    Polyethylene oxide (PEO) is one of the best candidates for solid state electrolyte due to its chemical stability and strong ability to form complex with lithium salts. Crystallization behavior of PEO directly affects the lithium ion transport, and in turn the ionic conductivity of the electrolyte. By adding two dimensional graphene oxide nanosheets into PEO matrix, mechanical property of the latter is significantly strengthened, while the crystallization behavior of PEO is also altered by the graphene oxide sheets. The crystallization of PEO/graphene oxide nanocomposites was studied by differential scanning calorimetry (DSC) and the orientations of graphene oxide and PEO crystal were studied by small angle X-ray scattering and wide angle X-ray diffraction. PEO/graphene oxide nanocomposite doped with lithium salt was further fabricated and characterized by electrochemical impedance spectroscopy. Anisotropic ionic conductivity was observed for the nanocomposite electrolyte due to the orientation of graphene oxide and directional growth of PEO crystals.

  15. Oxidation resistance of co-deposited Ni-SiC nanocomposite coating

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Ni-6.0%SiC (mass fraction) nanocomposite coating was prepared from a nickel sulfate bath by co-electrodeposition of Ni and SiC nanoparticles in an average size of 30 nm. The oxidation at 1 000 ℃ shows that the Ni-6.0%SiC nanocomposite coating has a superior oxidation resistance compared with the pure Ni film due to the formation of SiO2 oxide particles along grain boundaries,blocking the outward diffusion of Ni and changing the oxidation growth mechanism. The effect of SiC nanoparticles on the oxidation progress was discussed in detail.

  16. Striking multiple synergies created by combining reduced graphene oxides and carbon nanotubes for polymer nanocomposites

    Science.gov (United States)

    Song, Ping'an; Liu, Lina; Fu, Shenyuan; Yu, Youming; Jin, Chunde; Wu, Qiang; Zhang, Yan; Li, Qian

    2013-03-01

    The extraordinary properties of carbon nanotubes (CNTs) and graphene stimulate the development of advanced composites. Recently, several studies have reported significant synergies in the mechanical, electrical and thermal conductivity properties of polymer nanocomposites by incorporating their nanohybrids. In this work, we created polypropylene nanocomposites with homogeneous dispersion of CNTs and reduced graphene oxides via a facile polymer-latex-coating plus melt-mixing strategy, and investigated their synergistic effects in their viscoelastic, gas barrier, and flammability properties. Interestingly, the results show remarkable synergies, enhancing their melt modulus and viscosity, O2 barrier, and flame retardancy properties and respectively exhibiting a synergy percentage of 15.9%, 45.3%, and 20.3%. As previously reported, we also observed remarkable synergistic effects in their tensile strength (14.3%) and Young’s modulus (27.1%), electrical conductivity (32.3%) and thermal conductivity (34.6%). These impressive results clearly point towards a new strategy to create advanced materials by adding binary combinations of different types of nanofillers.

  17. Functional Iron Oxide-Silver Hetero-Nanocomposites: Controlled Synthesis and Antibacterial Activity

    Science.gov (United States)

    Trang, Vu Thi; Tam, Le Thi; Van Quy, Nguyen; Huy, Tran Quang; Thuy, Nguyen Thanh; Tri, Doan Quang; Cuong, Nguyen Duy; Tuan, Pham Anh; Van Tuan, Hoang; Le, Anh-Tuan; Phan, Vu Ngoc

    2017-02-01

    Iron oxide-silver nanocomposites are of great interest for their antibacterial and antifungal activities. We report a two-step synthesis of functional magnetic hetero-nanocomposites of iron oxide nanoparticles and silver nanoparticles (Fe3O4-Ag). Iron oxide nanoparticles were prepared first by a co-precipitation method followed by the deposition of silver nanoparticles via a hydrothermal route. The prepared Fe3O4-Ag hetero-nanocomposites were characterized by x-ray diffraction, transmission electron microscopy, high resolution transmission electron microscopy and vibrating sample magnetometry. Their antibacterial activities were investigated by using paper-disc diffusion and direct-drop diffusion methods. The results indicate that the Fe3O4-Ag hetero-nanocomposites exhibit excellent antibacterial activities against two Gram-negative bacterial strains (Salmonella enteritidis and Klebsiella pneumoniae).

  18. Green synthesis of Pd@graphene nanocomposite: Catalyst for the selective oxidation of alco

    Directory of Open Access Journals (Sweden)

    Abdulhadi H. Al-Marri

    2016-11-01

    Full Text Available Due to their excellent physicochemical properties and synergistic effect, graphene metallic NPs based nanocomposites have gained significant attention in various technological fields including catalysis. Here we demonstrate a single pot, facile and environmental friendly synthesis of catalytically active palladium(Pd@graphene nanocomposites (SP-HRG-Pd by the simultaneous reduction of graphene oxide (GRO and PdCl2 using Salvadora persica L. (miswak root extract (RE as bioreductant. The synthesis of SP-HRG-Pd was confirmed by various spectroscopic and microscopic techniques, including ultraviolet–visible (UV–vis, Fourier-transform infrared (FT-IR, Raman and X-ray photoelectron (XPS spectroscopy, X-ray powder diffraction (XRD and transmission electron microscopy (TEM. The polyphenolic (flavonoids and terpenoids rich contents of the miswak RE not only facilitated the reduction of graphene oxide and PdCl2 but also ensured the homogeneous binding of the Pd NPs on graphene, and through stabilization of the surface of SP-HRG-Pd nanocomposites. This also led to the enhanced dispersibility of as synthesized nanocomposites in aqueous solutions. The as-prepared SP-HRG-Pd nanocomposites also demonstrated excellent catalytic activity toward the selective oxidation of aromatic alcohols. Furthermore, in order to study the effect of calcination temperature and concentration of Pd NPs on the catalytic activities of nanocomposites, different samples of SP-HRG-Pd nanocomposites containing different amounts of Pd using various concentrations of Pd precursor were prepared and calcined at various temperatures.

  19. Novel Preparation of Calcium Borate/Graphene Oxide Nanocomposites and Their Tribological Properties in Oil

    Science.gov (United States)

    Li, Wei; Cheng, Zhi-Lin; Liu, Zan

    2017-01-01

    The calcium borate/graphene oxide (CB/GO) nanocomposites have been successfully prepared by a liquid phase-based ultrasonic-assisted stripping method, which were subsequently explored as lubricant additive. The structure and morphology of the as-prepared nanocomposites were characterized by FT-IR, XRD, Raman, TEM, EDS and TGA, revealing that CB nanoparticles were uniformly loaded on GO surfaces. The nanocomposites were highly dispersed into the base oil by sand milling. The tribological properties of CB/GO nanocomposites as lubricating oil additive were investigated using a four-ball machine, and the wear scar surfaces were observed by the 3D Laser Scanning Microscope. The results indicated that CB/GO nanocomposites were of excellent antifriction, antiwear ability and load-carrying capacity.

  20. Novel Preparation of Calcium Borate/Graphene Oxide Nanocomposites and Their Tribological Properties in Oil

    Science.gov (United States)

    Li, Wei; Cheng, Zhi-Lin; Liu, Zan

    2016-11-01

    The calcium borate/graphene oxide (CB/GO) nanocomposites have been successfully prepared by a liquid phase-based ultrasonic-assisted stripping method, which were subsequently explored as lubricant additive. The structure and morphology of the as-prepared nanocomposites were characterized by FT-IR, XRD, Raman, TEM, EDS and TGA, revealing that CB nanoparticles were uniformly loaded on GO surfaces. The nanocomposites were highly dispersed into the base oil by sand milling. The tribological properties of CB/GO nanocomposites as lubricating oil additive were investigated using a four-ball machine, and the wear scar surfaces were observed by the 3D Laser Scanning Microscope. The results indicated that CB/GO nanocomposites were of excellent antifriction, antiwear ability and load-carrying capacity.

  1. Effect of high shear mixing parameters and degassing temperature on the morphology of epoxy-clay nanocomposites

    KAUST Repository

    Al-Qadhi, Muneer

    2013-01-01

    Epoxy-clay nanocomposites were prepared by high shear mixing method using Nanomer I.30E nanoclay as nano-reinforcement in diglycidyl ether of bisphenol A (DGEBA). The effect of mixing speed and time on the nature and degree of clay dispersion were investigated by varying the mixing speed in the range of 500-8000 RPM and mixing time in the range of 15-90 minutes. The effect of degassing temperature on the morphology of the resultant nanocomposites was also studied. Scanning and transmission microscopy (SEM and TEM) along with x-ray diffraction (XRD) have been used to characterize the effect of shear mixing speed, mixing time and degassing temperature on the structure of the resultant nanocomposites. The SEM, TEM and XRD examinations demonstrated that the degree of clay dispersion was improved with increasing the high shear mixing speed and mixing time. The results showed that the optimum high shear mixing speed and mixing time were 6000 rpm and 60 min, respectively. It was observed that the structure of the nanocomposites that have been degassed at 65°C was dominated by ordered intercalated morphology while disordered intercalated with some exfoliated morphology was found for the sample degassed at 100°C for the first 2 hours of the degassing process. © (2013) Trans Tech Publications, Switzerland.

  2. Highly Efficient Near Infrared Photothermal Conversion Properties of Reduced Tungsten Oxide/Polyurethane Nanocomposites

    Directory of Open Access Journals (Sweden)

    Tolesa Fita Chala

    2017-07-01

    Full Text Available In this work, novel WO3-x/polyurethane (PU nanocomposites were prepared by ball milling followed by stirring using a planetary mixer/de-aerator. The effects of phase transformation (WO3 → WO2.8 → WO2.72 and different weight fractions of tungsten oxide on the optical performance, photothermal conversion, and thermal properties of the prepared nanocomposites were examined. It was found that the nanocomposites exhibited strong photoabsorption in the entire near-infrared (NIR region of 780–2500 nm and excellent photothermal conversion properties. This is because the particle size of WO3-x was greatly reduced by ball milling and they were well-dispersed in the polyurethane matrix. The higher concentration of oxygen vacancies in WO3-x contribute to the efficient absorption of NIR light and its conversion into thermal energy. In particular, WO2.72/PU nanocomposites showed strong NIR light absorption of ca. 92%, high photothermal conversion, and better thermal conductivity and absorptivity than other WO3/PU nanocomposites. Furthermore, when the nanocomposite with 7 wt % concentration of WO2.72 nanoparticles was irradiated with infrared light, the temperature of the nanocomposite increased rapidly and stabilized at 120 °C after 5 min. This temperature is 52 °C higher than that achieved by pure PU. These nanocomposites are suitable functional materials for solar collectors, smart coatings, and energy-saving applications.

  3. Facile hydrothermal preparation of titanium dioxide decorated reduced graphene oxide nanocomposite

    Science.gov (United States)

    Chang, Betty Yea Sze; Huang, Nay Ming; An’amt, Mohd Nor; Marlinda, Abdul Rahman; Norazriena, Yusoff; Muhamad, Muhamad Rasat; Harrison, Ian; Lim, Hong Ngee; Chia, Chin Hua

    2012-01-01

    A simple single-stage approach, based on the hydrothermal technique, has been introduced to synthesize reduced graphene oxide/titanium dioxide nanocomposites. The titanium dioxide nanoparticles are formed at the same time as the graphene oxide is reduced to graphene. The triethanolamine used in the process has two roles. It acts as a reducing agent for the graphene oxide as well as a capping agent, allowing the formation of titanium dioxide nanoparticles with a narrow size distribution (~20 nm). Transmission electron micrographs show that the nanoparticles are uniformly distributed on the reduced graphene oxide nanosheet. Thermogravimetric analysis shows the nanocomposites have an enhanced thermal stability over the original components. The potential applications for this technology were demonstrated by the use of a reduced graphene oxide/titanium dioxide nanocomposite-modified glassy carbon electrode, which enhanced the electrochemical performance compared to a conventional glassy carbon electrode when interacting with mercury(II) ions in potassium chloride electrolyte. PMID:22848166

  4. Processing, characterization and properties of oxide based nanocomposites

    Science.gov (United States)

    Bhaduri, Sutapa

    The synthesis, characterization and mechanical properties of oxide based nanocomposites are reported in this dissertation. Two binary systems are studied: Alsb2Osb3-MgO and Alsb2Osb3-ZrOsb2. Alsb2Osb3-MgO was chosen because of its relatively large field of solid solubilities at a moderate temperature. On the other hand, Alsb2Osb3-ZrOsb2 was chosen because it shows minimal solid solubility of the constituents. A novel "Auto Ignition" process using suitable fuels and oxidizers was utilized in the synthesis of nanocomposites and solid solutions. Thermodynamic calculations were carried out in predicting end point adiabatic temperatures (Tsbad) for each composition in both systems. Combustion temperatures were experimentally measured by means of a data acquisition system. Characterizations of the powders were carried out by x-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive analysis (EDAX) and differential thermal analysis (DTA). Heat treatment experiments were carried out to study the grain growth behavior. A hot isostatic pressing (HIP) model was developed for the present nanoceramics. Input parameters were carefully chosen for such nanomaterials. The as-synthesized nanocrystalline powders were consolidated to near theoretical density by hot isostatic pressing (HIPing) while retaining fine grain size. The experimental results were compared with the predictions of the model. Mechanical properties, such as room temperature toughness, low temperatures well as high temperature hardness, were determined for both systems. Room temperature hardness values were (2.89-7.79) GPa and fracture toughness was between 2.7 and 5.82 MPa.msp{1/2} for various compositions in the Alsb2Osb3-MgO system. Room temperature hardness values were between 5.33 and 8.71 GPa and fracture toughness values ranged from (5.3-9.62) MPa.msp{1/2} for various compositions in the Alsb2Osb3-ZrOsb2 system. Nanoindentation experiments were carried out to further explore the room

  5. Oxygen Barrier Properties and Melt Crystallization Behavior of Poly(ethylene terephthalate/Graphene Oxide Nanocomposites

    Directory of Open Access Journals (Sweden)

    Anna Szymczyk

    2015-01-01

    Full Text Available Poly(ethylene terephthalate nanocomposites with low loading (0.1–0.5 wt% of graphene oxide (GO have been prepared by using in situ polymerization method. TEM study of nanocomposites morphology has shown uniform distribution of highly exfoliated graphene oxide nanoplatelets in PET matrix. Investigations of oxygen permeability of amorphous films of nanocomposites showed that the nanocomposites had better oxygen barrier properties than the neat PET. The improvement of oxygen permeability for PET nanocomposite films over the neat PET is approximately factors of 2–3.3. DSC study on the nonisothermal crystallization behaviors proves that GO acts as a nucleating agent to accelerate the crystallization of PET matrix. The evolution of the lamellar nanostructure of nanocomposite and neat PET was monitored by SAXS during nonisothermal crystallization from the melt. It was found that unfilled PET and nanocomposite with the highest concentration of GO (0.5 wt% showed almost similar values of the long period (L=11.4 nm for neat PET and L=11.5 nm for PET/0.5GO.

  6. One-pot synthesis of cuprous oxide-reduced graphene oxide nanocomposite with enhanced photocatalytic and electrocatalytic performance

    Science.gov (United States)

    Han, Fugui; Li, Heping; Yang, Jun; Cai, Xiaodong; Fu, Li

    2016-03-01

    We report on the facile one-step synthesis of porous cuprous oxide nanoparticles on reduced graphene oxide (Cu2O-RGO) by synchronously reducing Cu2+ ions and GO with ethylene glycol. The basic chemical components, crystal structure and surface morphology of prepared nanocomposite was carefully characterized. The photocatalytic activities of the as-prepared nanocomposite was investigated by photodegrading methylene blue (MB) under visible light. The electrocatalytic property of the nanocomposite was investigated by electrocatalytic determination of acetaminophen. The results indicate that the corporation of RGO with Cu2O nanoparticles could high enhance the both photocatalytic and electrocatalytic properties. Moreover, we found that the content of RGO introduced into nanocomposite could highly affect the product properties.

  7. Synthesis of a novel biocompatible nanocomposite of graphene oxide and magnetic nanoparticles for drug delivery.

    Science.gov (United States)

    Aliabadi, Majid; Shagholani, Hamidreza; Yunessnia Lehi, Arash

    2017-05-01

    The combination of imaging and delivery systems through nanoscale material have been used to create new nanoparticle formulations for biological applications. Here, a magnetic nanocomposite consisting of superparamagnetic iron oxide nanoparticles (SPIONs), graphene oxide (GO), chitosan and poly(vinyl alcohol) (PVA) as biocompatible polymers was synthesized for applying in drug delivery and imaging agent. The nanocomposite was studied by various techniques including XRD, TEM, FE-SEM, FT-IR and VSM. SPIONs had an average diameter size about 10nm and showed superparamagnetic behavior. Also, TEM and SEM images showed that these nanoparticles successfully attached on the surface of GO sheets. Finally, 5-fu was loaded onto these nanocomposite particles in order to study of entrapment efficiency and drug release behavior of nanocomposite particles. They showed high drug entrapment efficiency and more and faster drug release in acidic pH. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Reduced Graphene Oxide/Au Nanocomposite for NO2 Sensing at Low Operating Temperature

    Directory of Open Access Journals (Sweden)

    Hao Zhang

    2016-07-01

    Full Text Available A reduced grapheme oxide (rGO/Au hybrid nanocomposite has been synthesized by hydrothermal treatment using graphite and HAuCl4 as the precursors. Characterization, including X-ray diffraction (XRD, Raman spectra, X-ray photoelecton spectroscopy (XPS and transmission electron microscopy (TEM, indicates the formation of rGO/Au. A gas sensor fabricated with rGO/Au nanocomposite was applied for NO2 detection at 50 °C. Compared with pure rGO, rGO/Au nanocomposite exhibits higher sensitivity, a more rapid response–recovery process and excellent reproducibility.

  9. Extrusion of polysaccharide nanocrystal reinforced polymer nanocomposites through compatibilization with poly(ethylene oxide).

    Science.gov (United States)

    Pereda, Mariana; El Kissi, Nadia; Dufresne, Alain

    2014-06-25

    Polysaccharide nanocrystals with a rodlike shape but with different dimensions and specific surface area were prepared from cotton and capim dourado cellulose, and with a plateletlike morphology from waxy maize starch granules. The rheological behavior of aqueous solutions of poly(ethylene oxide) (PEO) with different molecular weights when adding these nanoparticles was investigated evidencing specific interactions between PEO chains and nanocrystals. Because PEO also bears hydrophobic moieties, it was employed as a compatibilizing agent for the melt processing of polymer nanocomposites. The freeze-dried mixtures were used to prepare nanocomposite materials with a low density polyethylene matrix by extrusion. The thermal and mechanical behavior of ensuing nanocomposites was studied.

  10. Carbon-Nickel oxide nanocomposites: Preparation and charecterisation

    CSIR Research Space (South Africa)

    Tile, N

    2011-07-01

    Full Text Available Nanocomposite materials have wide range of applications in solar energy conversion. In this work, C-NiO nanocomposite coatings are prepared using sol-gel synthesis and deposited on aluminium substrates using a spin coater. The coatings are prepared...

  11. Mixed iron-manganese oxide nanoparticles

    NARCIS (Netherlands)

    Lai, Jriuan; Shafi, Kurikka V.P.M.; Ulman, Abraham; Loos, Katja; Yang, Nan-Loh; Cui, Min-Hui; Vogt, Thomas; Estournès, Claude; Locke, Dave C.

    2004-01-01

    Designing nanoparticles for practical applications requires knowledge and control of how their desired properties relate to their composition and structure. Here, we present a detailed systematic study of mixed iron-manganese oxide nanoparticles, showing that ultrasonication provides the high-energy

  12. A Novel Method of Mechanical Oxidation of CNT for Polymer Nanocomposite Application: Evaluation of Mechanical, Dynamic Mechanical, and Rheological Properties

    Directory of Open Access Journals (Sweden)

    Priyanka Pandey

    2014-01-01

    Full Text Available A new approach of oxidation of carbon nanotubes has been used to oxidize the CNTs. A comparative aspect of the mechanical oxidation and acid oxidation process has been established. FTIR analysis and titration method have shown the higher feasibility of the mechanical oxidation method to oxidize the CNTs. Comparatively less damage to the CNTs has been observed in case of mechanically oxidized as compared to acid oxidized CNTs. The mechanical properties of the nanocomposites reinforced with the acid oxidized CNT (ACNT and mechanically oxidized CNTs (McCNT were analyzed and relatively higher properties in the nanocomposites reinforced with McCNT were noticed. The less degree of entanglement in the McCNTs was noticed as compared to ACNTs. The dynamic mechanical analysis of the nanocomposites revealed much improved load transfer capability in the McCNT reinforced composites. Further, the rheological properties of the nanocomposites revealed the higher performance of McCNT reinforced composites.

  13. Syntheis and Photocurrent Performance of Graphene Oxide-CdTe/CdS Nanocomposite.

    Science.gov (United States)

    Ding, Liyun; Zhang, Bingyu; Li, Tao; Huang, Jun; Fan, Xiaochun

    2015-12-01

    Graphene with two-dimensional carbon nanostructures provides a potent strategy to enhance optoelectronic performance of semiconductor nanoparticles based light harvesting assemblies. Graphene oxide-CdTe/CdS (GO-CdTe/CdS) nanocomposites were successfully prepared by CdTe/CdS quantum dots (QDs) formed on the surface of graphene oxide sheets. The structure and optical properties of GO-CdTe/CdS nanocomposites were studied in detail. Photoluminescence measurements showed that the integration of CdTe/CdS QDs with graphene oxide significantly decreased its photoluminescence, which indicated effective transfer of photo-excited electrons from CdTe/CdS to graphene oxide. The generation of photocurrent on illumination of the GO-CdTe/CdS nanocomposite was studied. Significant enhancement in photocurrent induced by GO in CdTe/CdS QDs film had also been demonstrated due to increasing the charge separation and electron conduction.

  14. Preparation and mechanical properties of graphene oxide: cement nanocomposites.

    Science.gov (United States)

    Babak, Fakhim; Abolfazl, Hassani; Alimorad, Rashidi; Parviz, Ghodousi

    2014-01-01

    We investigate the performance of graphene oxide (GO) in improving mechanical properties of cement composites. A polycarboxylate superplasticizer was used to improve the dispersion of GO flakes in the cement. The mechanical strength of graphene-cement nanocomposites containing 0.1-2 wt% GO and 0.5 wt% superplasticizer was measured and compared with that of cement prepared without GO. We found that the tensile strength of the cement mortar increased with GO content, reaching 1.5%, a 48% increase in tensile strength. Ultra high-resolution field emission scanning electron microscopy (FE-SEM) used to observe the fracture surface of samples containing 1.5 wt% GO indicated that the nano-GO flakes were well dispersed in the matrix, and no aggregates were observed. FE-SEM observation also revealed good bonding between the GO surfaces and the surrounding cement matrix. In addition, XRD diffraction data showed growth of the calcium silicate hydrates (C-S-H) gels in GO cement mortar compared with the normal cement mortar.

  15. Fabrication of Bionic Superhydrophobic Manganese Oxide/Polystyrene Nanocomposite Coating

    Institute of Scientific and Technical Information of China (English)

    Xianghui Xu; Zhaozhu Zhang; Fang Guo; Jin Yang; Xiaotao Zhu; Xiaoyan Zhou; Qunji Xue

    2012-01-01

    A superhydrophobic manganese oxide/polystyrene (MnO2/PS) nanocomposite coating was fabricated by a facile spraying process.The mixture solution of MnO2/PS was poured into a spray gun,and then sprayed onto the copper substrate using 0.2 MPa nitrogen gas to construct superhydrophobic coating.The wettability of the composite coating was measured by sessile drop method.When the weight ratio of MnO2 to PS is 0.5:1,the maximum of contact angle (CA) (140°) is obtained at drying temperature of 180 ℃.As the content of MnO2 increases,the maximum of CA (155°) is achieved at 100 ℃.Surface morphologies and chemical composition were analyzed to understand the effect of the content of MnO2 nanorods and the drying temperature on CA.The results show that the wettability of the coating can be controlled by the content ofMnO2 nanorods and the drying temperature.Using the proposed method,the thickness of the coating can be controlled by the spraying times.If damaged,the coating can be repaired just by spraying the mixture solution again.

  16. Synthesizing mixed phase titania nanocomposites with enhanced photoactivity and redshifted photoresponse by reactive DC magnetron sputtering

    Science.gov (United States)

    Chen, Le

    Recent work points out the importance of the solid-solid interface in explaining the high photoactivity of mixed phase TiO2 catalysts. The goal of this research was to probe the synthesis-structure-function relationships of the solid-solid interfaces created by the reactive direct current (DC) magnetron sputtering of titanium dioxide. I hypothesize that the reactive DC magnetron sputtering is a useful method for synthesizing photo-catalysts with unique structure including solid-solid interfaces and surface defects that are associated with enhanced photoreactivity as well as a photoresponse shifted to longer wavelengths of light. I showed that sputter deposition provides excellent control of the phase and interface formation as well as the stoichiometry of the films. I explored the effects exerted by the process parameters of pressure, oxygen partial pressure, target power, substrate bias (RF), deposition incidence angle, and post annealing treatment on the structural and functional characteristics of the catalysts. I have successfully made pure and mixed phase TiO2 films. These films were characterized with UV-Vis, XPS, AFM, SEM, TEM, XRD and EPR, to determine optical properties, elemental stoichiometry, surface morphology, phase distribution and chemical coordination. Bundles of anatase-rutile nano-columns having high densities of dual-scale of interfaces among and within the columns are fabricated. Photocatalytic performance of the sputtered films as measured by the oxidation of the pollutant, acetaldehyde, and the reduction of CO2 for fuel (CH4) production was compared (normalized for surface area) to that of mixed phase TiO2 fabricated by other methods, including flame hydrolysis powders, and solgel deposited TiO 2 films. The sputtered mixed phase materials were far superior to the commercial standard (Degussa P25) and solgel TiO2 based on gas phase reaction of acetaldehyde oxidation under UV light and CO2 reduction under both UV and visible illuminations. The

  17. Size-dependent cytotoxicity and inflammatory responses of PEGylated silica-iron oxide nanocomposite size series

    Science.gov (United States)

    Injumpa, Wishulada; Ritprajak, Patcharee; Insin, Numpon

    2017-04-01

    Iron oxides nanoparticles have been utilized in biological systems and biomedical applications for many years because they are relatively safe and stable comparing to other magnetic nanomaterials. In some applications, iron oxide nanoparticles were modified with silica in order to be more stable in biological systems and able to be functionalized with various functional groups. Moreover, poly(ethylene glycol) (PEG) was one on the most used polymer to graft onto the nanoparticles in order to increase their biocompatibility, dispersibility and stability in aqueous solutions. Therefore, the nanocomposites comprising iron oxide nanoparticles, silica, and PEG could become multifunctional carriers combining superparamagnetic character, multi-functionality and high stability in biological environments. Herein, we reported the preparation of the nanocomposites and effects of their sizes on cytotoxicity and inflammatory responses. The PEGylated silica-iron oxide nanocomposites were prepared by coating of poly(poly(ethylene glycol) monomethyl ether methacrylate) (PPEGMA) on magnetic nanoparticle-silica nanocomposites via Atom Transfer Radical Polymerization (ATRP). The iron oxide nanoparticles were synthesized using a thermal decomposition method. The silica shells were then coated on iron oxides nanoparticles using reverse microemulsion and sol-gel methods. The size series of the nanocomposites with the diameter of 24.86±4.38, 45.24±5.00, 98.10±8.88 and 202.22±6.70 nm as measured using TEM were obtained. Thermogravimetric analysis (TGA) was used for the determination of % weight of PPEGMA on the nanocomposites showing the weight loss of ranging from 65% for smallest particles to 30% for largest particles. The various sizes (20, 40, 100, 200 nm) and concentrations (10, 100, 1000 μg/mL) of the nanocomposites were tested for their cytotoxicity in fibroblast and macrophage cell lines using MTT assay. The different sizes did not affect cell viability of fibroblast, albeit

  18. Synergistic effects of alkylated graphene oxide on the properties of polypropylene-based carbon nanocomposites.

    Science.gov (United States)

    Yun, Young Soo; Pyo, Hye-Ri; Lee, Jae Yun; Chin, In-Joo; Jin, Hyoung-Joon

    2013-10-01

    Polypropylene (PP)/carbon black (CB)-alkylated graphene oxide (AGO) hybrid nanocomposites were prepared via solution process and the synergistic effects of AGO on the properties of the PP/CB nanocomposites were investigated. AGO at a content of only 0.2 wt% formed an overlapped network structure in the PP matrix and affected the electrical, thermal and mechanical properties of the PP/CB nanocomposites. Specifically, PP/CB (5 wt%)-AGO (0.2 wt%) nanocomposites exhibited an electrical percolation threshold at lower CB contents than the PP/CB nanocomposites did, and the sheet resistance was decreased to 2.3 x 10(7) omega/sq. The thermal degradation temperature and recrystallization temperature of the PP/CB (10 wt%) nanocomposites were increased by 11.3 and 1.6 degrees C, respectively, by the addition of 0.2 wt% AGO. In addition, the Young's modulus of the PP/CB (10 wt%) nanocomposite was increased from 438.1 to 540.1 MPa.

  19. Preparation of Zinc Oxide-Starch Nanocomposite and Its Application on Coating

    Science.gov (United States)

    Ma, Jinxia; Zhu, Wenhua; Tian, Yajun; Wang, Zhiguo

    2016-04-01

    A new production method of zinc oxide (ZnO)-starch nanocomposite was invented in this study. Starch was dissolved in zinc chloride (ZnCl2) solution (65 wt%) at 80 °C. Then, ZnO-starch nanocomposite was achieved when the pH of the solution was adjusted to 8.4 by NaOH solution (15 wt%). ZnO nanoparticles were also obtained when the generated ZnO-starch nanocomposite was calcined at 575 °C. The properties of ZnO-starch nanocomposite and ZnO nanoparticle were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The results indicated that the sizes of ZnO-starch composite and ZnO particle were 40-60 nm. UV blocking effect was observed from both ZnO-starch nanocomposite and ZnO nanoparticle. The ZnO-starch nanocomposite was used to directly coat the surface of plain paper with a laboratory paper coater. The surface strength and smoothness of paper were improved by the coating of ZnO-starch nanocomposite. The antibacterial property was also identified from the coated paper.

  20. Preparation, characterization, and antibacterial activity of silver nanoparticle-decorated graphene oxide nanocomposite.

    Science.gov (United States)

    Shao, Wei; Liu, Xiufeng; Min, Huihua; Dong, Guanghui; Feng, Qingyuan; Zuo, Songlin

    2015-04-01

    In this work, we report a facile and green approach to prepare a uniform silver nanoparticles (AgNPs) decorated graphene oxide (GO) nanocomposite (GO-Ag). The nanocomposite was fully characterized by transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectra, ultraviolet-visible (UV-vis) absorption spectra, and X-ray photoelectron spectroscopy (XPS), which demonstrated that AgNPs with a diameter of approximately 22 nm were uniformly and compactly deposited on GO. To investigate the silver ion release behaviors, HEPES buffers with different pH (5.5, 7, and 8.5) were selected and the mechanism of release actions was discussed in detail. The cytotoxicity of GO-Ag nanocomposite was also studied using HEK 293 cells. GO-Ag nanocomposite displayed good cytocompatibility. Furthermore, the antibacterial properties of GO-Ag nanocomposite were studied using Gram-negative E. coli ATCC 25922 and Gram-positive S. aureus ATCC 6538 by both the plate count method and disk diffusion method. The nanocomposite showed excellent antibacterial activity. These results demonstrated that GO-Ag nanocomposite, as a kind of antibacterial material, had a great promise for application in a wide range of biomedical applications.

  1. Nickel Oxide and Nickel Co-doped Graphitic Carbon Nitride Nanocomposites and its Octylphenol Sensing Application

    KAUST Repository

    Gong, Wanyun

    2015-11-16

    Nickel oxide and nickel co-doped graphitic carbon nitride (NiO-Ni-GCN) nanocomposites were successfully prepared by thermal treatment of melamine and NiCl2 6H2O. NiO-Ni-GCN nanocomposites showed superior electrochemical catalytic activity for the oxidation of octylphenol to pure GCN. A detection method of octylphenol in environmental water samples was developed based at NiO-Ni-GCN nanocomposites modified electrode under infrared light irradiation. Differential pulse voltammetry was used as the analytic technique of octylphenol, exhibiting stable and specific concentration-dependent oxidation signal in the presence of octylphenol in the range of 10nM to 1μM and 1μM to 50μM, with a detection limit of 3.3nM (3S/N). © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Preparation, Characterization, and Properties of In Situ Formed Graphene Oxide/Phenol Formaldehyde Nanocomposites

    Directory of Open Access Journals (Sweden)

    Weihua Xu

    2013-01-01

    Full Text Available Graphene oxide (GO has shown great potential to be used as fillers to develop polymer nanocomposites for important applications due to their special 2D geometrical structure as well as their outstanding mechanical, thermal, and electrical properties. In this work, GO was incorporated into phenol formaldehyde (PF resin by in situ polymerization. The morphologies and structures of GO sheets were characterized by FTIR, XRD, and AFM methods. The structure and properties of the GO/PF nanocomposites were characterized using FTIR, XRD, DSC, and TGA methods. Effects of GO content, reactive conditions, and blending methods on the structure and properties of GO/PF nanocomposites were studied. It was found that due to the well dispersion of GO sheets in polymer matrix and the strong interfacial interaction between the GO sheets and PF matrix, the thermal stability and thermal mechanical properties of the GO/PF nanocomposites were greatly enhanced.

  3. Effect of various amounts of graphene oxide on the degradation characteristics of the ZnSe/graphene nanocomposites

    Science.gov (United States)

    Hsieh, S. H.; Chen, W. J.; Yeh, T. H.

    2015-12-01

    In this work, the graphene oxide (GO) sheets were synthesized by modified Hummers and Offeman's method. The GO was mixed with ZnSe that was prepared using various amounts of N2H4 at a ratio of (0.25-2):1 to form precursors. The ZnSe/graphene nanocomposites were synthesized under hydrothermal conditions (180 °C; 12 h) from the previous precursor. Obtained ZnSe/graphene photocatalysts were characterized by X-ray diffraction analysis (XRD), Fourier transform infrared (FTIR) spectroscopy, UV-vis diffuse reflection spectroscopy, transmission electron microscope, scanning electron microscope, Raman spectra and X-ray photoelectron spectroscopy (XPS). Photocatalytic activity under visible light is evaluated in methylene blue (MB) dye degradation reaction in aqueous phase. The results show that the formation of ZnSe/graphene nanocomposite is depend on ratio of the addition of GO to the amount of ZnSe-N2H4. The optimum degradation efficiency of the ZnSe/graphene nanocomposites on MB increases with increasing the ratio of the addition of GO to the amount of ZnSe-N2H4. When the amount of N2H4 increased from 5 ml to 7 ml, the ratio of the addition of GO to the amount of ZnSe-N2H4 increased from 1 to 1.25.

  4. Preparation and Property Study of Graphene Oxide Reinforced Epoxy Resin Insulation Nanocomposites with High Heat Conductivity

    Science.gov (United States)

    Shan, Xinran; Liu, Yongchang; Wu, Zhixiong; Liu, Huiming; Zhang, Zhong; Huang, Rongjin; Huang, Chuanjun; Liu, Zheng; Li, Laifeng

    2017-02-01

    In this paper, graphene oxide reinforced epoxy resin nanocomposites were successfully prepared. Compared with unmodified epoxy resin, the heat conductivity of the graphene oxide reinforced epoxy resin nanocomposites had been improved while keeping the insulation performance. The tensile strength was investigated at both room temperature (300 K) and liquid nitrogen temperature (77 K). And the fracture surfaces were examined by scanning electron microscopy (SEM). Results showed that the materials had excellent mechanical properties, which could be advantages for the applications as insulating layer in low temperature superconducting magnets.

  5. Phase change induced by polypyrrole in iron-oxide polypyrrole nanocomposite

    Indian Academy of Sciences (India)

    Komilla Suri; S Annapoorni; R P Tandon

    2001-12-01

    Nanocomposites of polypyrrole and iron oxide were prepared using simultaneous gelation and polymerization processes. Varied amounts of pyrrole monomer were added to a solution containing iron nitrate as precursor and 2-methoxy ethanol as solvent. The presence of oxide and polypyrrole was confirmed by using X-ray and FTIR techniques. Some of these nanocomposites exhibited magnetic behaviour. SEM studies of powders indicated presence of nanosized particles. Electrical conductivity studies of powders showed a slight variation in conductivity for lower concentration of pyrrole, with a sudden increase in conductivity at 15% of pyrrole concentration. A transition from a nonmagnetic to magnetic phase was also observed at the same concentration.

  6. Design and preliminary test of a fluidised bed photoreactor for ethylene oxidation on mesoporous mixed SiO2/TiO2 nanocomposites under UV-A illumination

    Directory of Open Access Journals (Sweden)

    Maria Lucia V. de Chiara

    2014-12-01

    Full Text Available Ethylene (C2H4 is a plant hormone that has numerous effects on many horticultural and ornamental crops. It accelerates senescence, stimulates chlorophyll loss, enhances excessive softening, promotes discoloration and browning during storage of fresh produce. Among the techniques used to remove or inhibit ethylene action during postharvest handling of fresh products (potassium-based system, high temperature catalytic oxidation, inhibition of ethylene receptors, the use of titanium oxide (TiO2-based materials with photocatalytic activity under ultraviolet (UV light is one of the most promising. A fluidised-bed photoreactor (FBP was designed to decompose ethylene in the storage room atmosphere, and the relative prototype was manufactured. Since TiO2 powder alone is not suitable for use within a fluidised bed, preliminary tests to select the best support were performed. Alumina microspheres showed a good fluidisation behavior; its functionality was tested with different kind of support material and actual photocatalytic activity was tested using SiO2/TiO2-coated alumina microspheres. A reduction of approximately 72% of ethylene concentration in the tested 40 ppm ethylene gas mixture was observed after 4.5 h of 36W UV light exposure. FBP resulted to be suitable to avoid the detrimental presence of C2H4 in the atmosphere surrounding fresh products within cold storage rooms.

  7. Selective propene oxidation on mixed metal oxide catalysts

    CERN Document Server

    James, D W

    2002-01-01

    Selective catalytic oxidation processes represent a large segment of the modern chemical industry and a major application of these is the selective partial oxidation of propene to produce acrolein. Mixed metal oxide catalysts are particularly effective in promoting this reaction, and the two primary candidates for the industrial process are based on iron antimonate and bismuth molybdate. Some debate exists in the literature regarding the operation of these materials and the roles of their catalytic components. In particular, iron antimonate catalysts containing excess antimony are known to be highly selective towards acrolein, and a variety of proposals for the enhanced selectivity of such materials have been given. The aim of this work was to provide a direct comparison between the behaviour of bismuth molybdate and iron antimonate catalysts, with additional emphasis being placed on the component single oxide phases of the latter. Studies were also extended to other antimonate-based catalysts, including coba...

  8. Constructing Ionic Liquid-Filled Proton Transfer Channels within Nanocomposite Membrane by Using Functionalized Graphene Oxide.

    Science.gov (United States)

    Wu, Wenjia; Li, Yifan; Chen, Pingping; Liu, Jindun; Wang, Jingtao; Zhang, Haoqin

    2016-01-13

    Herein, nanocomposite membranes are fabricated based on functionalized graphene oxides (FGOs) and sulfonated poly(ether ether ketone) (SPEEK), followed by being impregnated with imidazole-type ionic liquid (IL). The functional groups (acidic group or basic group) on FGOs generate strong interfacial interactions with SPEEK chains and then adjust their motion and stacking. As a result, the nanocomposite membranes possess tunable interfacial domains as determined by its free volume characteristic, which provides regulated location for IL storage. The stored ILs act as hopping sites for water-free proton conduction along the FGO-constructed interfacial channels. The microstructure at SPEEK-FGO interface governs the IL uptake and distribution in nanocomposite membrane. Different from GO and vinyl imidazole functionalized GO (VGO), the presence of acidic (-SO3H) groups confers the p-styrenesulfonic acid functionalized GO (SGO) incorporated nanocomposite membrane loose interface and strong electrostatic attraction with imidazole-type IL, imparting an enhanced IL uptake and anhydrous proton conductivity. Nanocomposite membrane containing 7.5% SGO attains the maximum IL uptake of 73.7% and hence the anhydrous conductivity of 21.9 mS cm(-1) at 150 °C, more than 30 times that of SPEEK control membrane (0.69 mS cm(-1)). In addition, SGOs generate electrostatic attractions to the ILs confined within SGO-SPEEK interface, affording the nanocomposite membrane enhanced IL retention ability.

  9. Nacre-inspired integrated strong and tough reduced graphene oxide-poly(acrylic acid) nanocomposites

    Science.gov (United States)

    Wan, Sijie; Hu, Han; Peng, Jingsong; Li, Yuchen; Fan, Yuzun; Jiang, Lei; Cheng, Qunfeng

    2016-03-01

    Inspired by the relationship between interface interactions and the high performance mechanical properties of nacre, a strong and tough nacre-inspired nanocomposite was demonstrated based on graphene oxide (GO) and polyacrylic acid (PAA) prepared via a vacuum-assisted filtration self-assembly process. The abundant hydrogen bonding between GO and PAA results in both high strength and toughness of the bioinspired nanocomposites, which are 2 and 3.3 times higher than that of pure reduced GO film, respectively. In addition, the effect of environmental relative humidity on the mechanical properties of bioinspired nanocomposites is also investigated, and is consistent with previous theoretical predictions. Moreover, this nacre-inspired nanocomposite also displays high electrical conductivity of 108.9 S cm-1. These excellent physical properties allow this type of nacre-inspired nanocomposite to be used in many applications, such as flexible electrodes, aerospace applications, and artificial muscles etc. This nacre-inspired strategy also opens an avenue for constructing integrated high performance graphene-based nanocomposites in the near future.

  10. Hybrid nanocomposite based on cellulose and tin oxide: growth, structure, tensile and electrical characteristics

    Directory of Open Access Journals (Sweden)

    Suresha K Mahadeva and Jaehwan Kim

    2011-01-01

    Full Text Available A highly flexible nanocomposite was developed by coating a regenerated cellulose film with a thin layer of tin oxide (SnO2 by liquid-phase deposition. Tin oxide was crystallized in solution and formed nanocrystal coatings on regenerated cellulose. The nanocrystalline layers did not exfoliate from cellulose. Transmission electron microscopy and energy dispersive x-ray spectroscopy suggest that SnO2 was not only deposited over the cellulose surface, but also nucleated and grew inside the cellulose film. Current–voltage characteristics of the nanocomposite revealed that its electrical resistivity decreases with deposition time, with the lowest value obtained for 24 h of deposition. The cellulose–SnO2 hybrid nanocomposite can be used for biodegradable and disposable chemical, humidity and biosensors.

  11. PREPARATION OF POLYSULFONAMIDE AND MODIFIED TITANIUM OXIDE NANOCOMPOSITES BY IN-SITU POLYMERIZATION

    Institute of Scientific and Technical Information of China (English)

    WANG Weitao; LIU Li; DENG Jie; WANG Xiaopeng; TANG Zhiyong

    2006-01-01

    A kind of new nano composite with ultraviolet (UV) ray resistance and high temperature stability was prepared by in-situ polymerization in low temperature. Polysulfonamide (PSA) was synthesized with 4, 4'-diaminodiphenyl sulfone (DDS) and terephthaloyl chloride (TPC) in the common solvent N, N-Dimethyl- -acetamide (DMAc). Nano filler is a certain nano titanium oxide modified by silicon oxide (TMS), which plays the role of UV resistance additives. Properties of the novel composite materials were characterized by Atomic Force microscopy (AFM), thermal gravimetric Analysis (TGA) and Ultraviolet Spectroscopy. AFM had showed the sizes and distributions of TMS particles in the nanocomposite. Ultraviolet Spectroscopy for the nanocomposites showed a large absorption in UV band. TGA showed the decomposition temperature was increased over ten degrees with 0.5% wt TMS for this nanocomposite compared with pure PSA.

  12. Integrated Chemical Systems: The Simultaneous Formation of Hybrid Nanocomposites of Iron Oxide and Organo Silsesquioxanes

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, L; Clapsaddle, B; Jr., J S; Schaefer, D; Shea, K

    2004-10-15

    A sol-gel approach for the synthesis of hybrid nanocomposites of iron oxide and bridged polysilsesquioxanes has been established. The procedures allow for the simultaneous formation of iron oxide and polysilsesquioxane networks in monolithic xerogels and aerogels. These hybrid nanocomposites are synthesized from FeCl{sub 3} {center_dot} 6H{sub 2}O and functionalized silsesquioxane monomers in a one-pot reaction using epoxides as a gelation agent. The porosity and microstructure of the materials has been determined by nitrogen porosimetry, electron microscopy and ultra small angle X-ray scattering (USAXS). The hybrid nanocomposites exhibit a uniform dispersion of both components with no evidence for phase separation at length scales > 5 nm. At this limit of resolution it is not possible to distinguish between two independent interpenetrating networks integrated at molecular length scales or a random copolymer or mixtures of both.

  13. Facile preparation of reduced graphene oxide - ruthenium oxide nanocomposite electrodes for high-performance supercapacitors

    Science.gov (United States)

    Amir, Fatima; Pham, Viet; Dickerson, James; Winthrop University Team; CFN-Brookhaven National Lab Team

    2015-03-01

    Herein we report a facile approach of synthesis of graphene oxide (GO) sheets modified with ruthenium oxide (RuO2) nanoparticles, followed by a reduction of graphene oxide in an alkaline medium. The as-prepared reduced graphene oxide (rGO)/ruthenium oxide (RuO2) nanocomposite was used for the fabrication of a symmetric supercapacitor. The specific capacitance and charge-discharge periods of the supercapacitor were found to be dependent on both the structural and morphological properties, and the electrolytes used. Surface morphology analysis using scanning electron microscopy (SEM) shows the RuO2 nanoparticles decorating rGO sheets, comprising a highly porous surface. Structural analysis obtained by x-ray diffraction (XRD) revealed an amorphous structure that is necessary to achieve a high cycling rate capability. The electrochemical properties of rGO/RuO2 were measured in a two electrodes system, using two different electrolytes: H2SO4andNa2SO4. The specific capacitance of rGO/RuO2 in H2SO4 was found to be 318 F/g, and is much higher than that of Na2SO4 (184 F/g).

  14. Enhanced photoluminescence in transparent thin films of polyaniline–zinc oxide nanocomposite prepared from oleic acid modified zinc oxide nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Sajimol Augustine, M., E-mail: sajimollazar@gmail.com [Department of Physics, St. Teresa' s College, Kochi-11, Kerala (India); Jeeju, P.P.; Varma, S.J.; Francis Xavier, P.A. [Division for Research in Advanced Materials, Department of Physics, Cochin University of Science and Technology, Kochi-22, Kerala (India); Jayalekshmi, S., E-mail: lakshminathcusat@gmail.com [Division for Research in Advanced Materials, Department of Physics, Cochin University of Science and Technology, Kochi-22, Kerala (India)

    2014-07-01

    Oleic acid capped zinc oxide (ZnO) nanoparticles have been synthesized by a wet chemical route. The chemical oxidative method is employed to synthesize polyaniline (PANI) and PANI/ZnO nanocomposites doped with four different dopants such as orthophosphoric acid (H{sub 3}PO{sub 4}), hydrochloric acid (HCl), naphthalene-2-sulphonic acid and camphor sulphonic acid (CSA). The samples have been structurally characterized by X-ray diffraction (XRD), field emission scanning electron microscopy and Fourier transform infrared (FT-IR) spectroscopic techniques. A comparison of the photoluminescence (PL) emission intensity of PANI and PANI/ZnO nanocomposites is attempted. The enhanced PL intensity in PANI/ZnO nanocomposites is caused by the presence of nanostructured and highly fluorescent ZnO in the composites. It has been observed that, among the composites, the H{sub 3}PO{sub 4} doped PANI/ZnO nanocomposite is found to exhibit the highest PL intensity because of the higher extent of (pi) conjugation and the more orderly arrangement of the benzenoid and quinonoid units. In the present work, transparent thin films of PANI and PANI/ZnO nanocomposite for which PL intensity is found to be maximum, have been prepared after re-doping with CSA by the spin-coating technique. The XRD pattern of the PANI/ZnO film shows exceptionally good crystallanity compared to that of pure PANI, which suggests that the addition of ZnO nanocrystals helps in enhancing the crystallanity of the PANI/ZnO nanocomposite. There is a significant increase in the PL emission intensity of the PANI/ZnO nanocomposite film making it suitable for the fabrication of optoelectronic devices. - Highlights: • Oleic acid capped zinc oxide nanoparticles are synthesized by wet chemical method. • Polyaniline/zinc oxide nanocomposites are prepared by in-situ polymerization. • Polyaniline and polyaniline/zinc oxide thin films are deposited using spin-coating. • Enhanced photoluminescence is observed in polyaniline

  15. Heterogeneous catalysis of mixed oxides perovskite and heteropoly catalysts

    CERN Document Server

    Misono, M

    2014-01-01

    Mixed oxides are the most widely used catalyst materials for industrial catalytic processes. The principal objective of this book is to describe systematically the mixed oxide catalysts, from their fundamentals through their practical applications.  After describing concisely general items concerning mixed oxide and mixed oxide catalysts, two important mixed oxide catalyst materials, namely, heteropolyacids and perovskites, are taken as typical examples and discussed in detail. These two materials have several advantages: 1. They are, respectively, typical examples of salts of oxoacids an

  16. Water oxidation catalysis by birnessite@iron oxide core-shell nanocomposites.

    Science.gov (United States)

    Elmaci, Gökhan; Frey, Carolin E; Kurz, Philipp; Zümreoğlu-Karan, Birgül

    2015-03-16

    In this work, magnetic nanocomposite particles were prepared for water oxidation reactions. The studied catalysts consist of maghemite (γ-Fe2O3), magnetite (Fe3O4), and manganese ferrite (MnFe2O4) nanoparticles as cores coated in situ with birnessite-type manganese oxide shells and were characterized by X-ray diffraction, transmission electron microscopy, scanning electron microscopy, thermal, chemical, and surface analyses, and magnetic measurements. The particles were found to be of nearly spherical core-shell architectures with average diameter of 150 nm. Water oxidation catalysis was examined using Ce(4+) as the sacrificial oxidant. All core-shell particles were found to be active water oxidation catalysts. However, the activity was found to depend on a variety of factors like the type of iron oxide core, the structure and composition of the shell, the coating characteristics, and the surface properties. Catalysts containing magnetite and manganese ferrite as core materials displayed higher catalytic activities per manganese ion (2650 or 3150 mmolO2 molMn(-1) h(-1)) or per mass than nanoiron oxides (no activity) or birnessite alone (1850 mmolO2 molMn(-1) h(-1)). This indicates synergistic effects between the MnOx shell and the FeOx core of the composites and proves the potential of the presented core-shell approach for further catalyst optimization. Additionally, the FeOx cores of the particles allow magnetic recovery of the catalyst and might also be beneficial for applications in water-oxidizing anodes because the incorporation of iron might enhance the overall conductivity of the material.

  17. Apoptosis inducing ability of silver decorated highly reduced graphene oxide nanocomposites in A549 lung cancer.

    Science.gov (United States)

    Khan, Merajuddin; Khan, Mujeeb; Al-Marri, Abdulhadi H; Al-Warthan, Abdulrahman; Alkhathlan, Hamad Z; Siddiqui, Mohammed Rafiq H; Nayak, Vadithe Lakshma; Kamal, Ahmed; Adil, Syed F

    2016-01-01

    Recently, graphene and graphene-based materials have been increasingly used for various biological applications due to their extraordinary physicochemical properties. Here, we demonstrate the anticancer properties and apoptosis-inducing ability of silver doped highly reduced graphene oxide nanocomposites synthesized by employing green approach. These nano composites (PGE-HRG-Ag) were synthesized by using Pulicaria glutinosa extract (PGE) as a reducing agent and were evaluated for their anticancer properties against various human cancer cell lines with tamoxifen as the reference drug. A correlation between the amount of Ag nanoparticles on the surface of highly reduced graphene oxide (HRG) and the anticancer activity of nanocomposite was observed, wherein an increase in the concentration of Ag nanoparticles on the surface of HRG led to the enhanced anticancer activity of the nanocomposite. The nanocomposite PGE-HRG-Ag-2 exhibited more potent cytotoxicity than standard drug in A549 cells, a human lung cancer cell line. A detailed investigation was undertaken and Fluorescence activated cell sorting (FACS) analysis demonstrated that the nanocomposite PGE-HRG-Ag-2 showed G0/G1 phase cell cycle arrest and induced apoptosis in A549 cells. Studies such as, measurement of mitochondrial membrane potential, generation of reactive oxygen species (ROS) and Annexin V-FITC staining assay suggested that this compound induced apoptosis in human lung cancer cells.

  18. Preparation and antibacterial activity of chitosan-based nanocomposites containing bentonite-supported silver and zinc oxide nanoparticles for water disinfection

    CSIR Research Space (South Africa)

    Motshekga, SC

    2015-07-01

    Full Text Available -assisted synthesis method. The resulting bentonite-supported silver and zinc oxide nanoparticles were dispersed in a chitosan biopolymer to prepare bentonite chitosan nanocomposites. The obtained bentonite chitosan nanocomposites were characterized with BET surface...

  19. Graphene-based transition metal oxide nanocomposites for the oxygen reduction reaction

    Science.gov (United States)

    Sun, Meng; Liu, Huijuan; Liu, Yang; Qu, Jiuhui; Li, Jinghong

    2015-01-01

    The development of low cost, durable and efficient nanocatalysts to substitute expensive and rare noble metals (e.g. Pt, Au and Pd) in overcoming the sluggish kinetic process of the oxygen reduction reaction (ORR) is essential to satisfy the demand for sustainable energy conversion and storage in the future. Graphene based transition metal oxide nanocomposites have extensively been proven to be a type of promising highly efficient and economic nanocatalyst for optimizing the ORR to solve the world-wide energy crisis. Synthesized nanocomposites exhibit synergetic advantages and avoid the respective disadvantages. In this feature article, we concentrate on the recent leading works of different categories of introduced transition metal oxides on graphene: from the commonly-used classes (FeOx, MnOx, and CoOx) to some rare and heat-studied issues (TiOx, NiCoOx and Co-MnOx). Moreover, the morphologies of the supported oxides on graphene with various dimensional nanostructures, such as one dimensional nanocrystals, two dimensional nanosheets/nanoplates and some special multidimensional frameworks are further reviewed. The strategies used to synthesize and characterize these well-designed nanocomposites and their superior properties for the ORR compared to the traditional catalysts are carefully summarized. This work aims to highlight the meaning of the multiphase establishment of graphene-based transition metal oxide nanocomposites and its structural-dependent ORR performance and mechanisms.

  20. Effect of the chemical nature of metal oxide on adhesion to the polyacrylate matrix in filled nanocomposites

    Science.gov (United States)

    Terziyan, T. V.; Safronov, A. P.; Petrov, A. V.; Volodina, N. S.; Beketov, I. V.

    2014-08-01

    The morphology, particle size, and thermochemical properties of the surface of oxides Al2O3, NiO, TiO2, ZnO, and ZrO2 obtained by the wire electroexplosion method were studied. The nanoparticles are spherical, with a mean diameter of 54-86 nm depending on the nature of the oxide. The hydrophilicity of the surface of metal oxide nanopowders was found to change in the series NiO-ZrO2-TiO2-ZnO-Al2O3. Nanocomposites with widely varied compositions were obtained from butyl methacrylate copolymer with 5 wt % methacrylic acid and the oxides under study. The enthalpies of dissolution of the composites in chloroform were determined by Calvet calorimetry. The enthalpies of copolymer mixing with oxides were calculated using the thermochemical cycle. The limiting enthalpies of copolymer adhesion to the oxide surface were calculated from the thermochemical data. The limiting adhesion enthalpy was shown to be negative for all oxides under study; these values decreased in magnitude as the surface hydrophilicity increased. The results were analyzed from the viewpoint of balance between the specific and dispersion interactions at the interface.

  1. Critical experiments with mixed oxide fuel

    Energy Technology Data Exchange (ETDEWEB)

    Harris, D.R. [Rensselaer Polytechnic Institute, Troy, NY (United States)

    1997-06-01

    This paper very briefly outlines technical considerations in performing critical experiments on weapons-grade plutonium mixed oxide fuel assemblies. The experiments proposed would use weapons-grade plutonium and Er{sub 2}O{sub 3} at various dissolved boron levels, and for specific fuel assemblies such as the ABBCE fuel assembly with five large water holes. Technical considerations described include the core, the measurements, safety, security, radiological matters, and licensing. It is concluded that the experiments are feasible at the Rensselaer Polytechnic Institute Reactor Critical Facility. 9 refs.

  2. Ultrasonic-assisted synthesis and magnetic studies of iron oxide/MCM-41 nanocomposite

    Energy Technology Data Exchange (ETDEWEB)

    Ursachi, Irina [Department of Physics ' Alexandru Ioan Cuza' University of Iasi, 11 Carol I Boulevard, 700506 Iasi (Romania); Vasile, Aurelia [Department of Chemistry, ' Alexandru Ioan Cuza' University of Iasi, 11 Carol I Boulevard, 700506 Iasi (Romania); Ianculescu, Adelina [Department of Oxide Materials and Engineering, Polytechnics University of Bucharest, 1-7 Gh. Polizu, 011061 Bucharest (Romania); Vasile, Eugeniu [METAV S.A., Research and Development, 31 C.A. Rosetti, 020011, Bucharest (Romania); Stancu, Alexandru, E-mail: alstancu@uaic.ro [Department of Physics ' Alexandru Ioan Cuza' University of Iasi, 11 Carol I Boulevard, 700506 Iasi (Romania)

    2011-11-01

    Highlights: {yields} A quick and facile route for the synthesis of iron oxide/MCM-41 nanocomposite. {yields} Magnetic nanoparticles were stabilized inside the pores of mesoporous silica MCM-41. {yields} The pore size of MCM-41 dictates the properties of iron oxide nanoparticles. {yields} The procedure provides a narrow size distribution of magnetic nanoparticles. - Abstract: Iron oxide nanoparticles were stabilized within the pores of mesoporous silica MCM-41 amino-functionalized by a sonochemical method. Formation of iron oxide nanoparticles inside the mesoporous channels of amino-functionalized MCM-41 was realized by wet impregnation using iron nitrate, followed by calcinations at 550 deg. C in air. The effect of functionalization level on structural and magnetic properties of obtained nanocomposites was studied. The resulting materials were characterized by powder X-ray diffraction (XRD), high-resolution transmission electron microscopy and selected area electron diffraction (HRTEM and SAED), vibrating sample and superconducting quantum interface magnetometers (VSM and SQUID) and nitrogen adsorption-desorption isotherms measurements. The HRTEM images reveal that the most of the iron oxide nanoparticles were dispersed inside the mesopores of silica matrix and the pore diameter of the amino-functionalized MCM-41 matrix dictates the particle size of iron oxide nanoparticles. The obtained material possesses mesoporous structure and interesting magnetic properties. Saturation magnetization value of magnetic iron oxide nanopatricles stabilized in MCM-41 amino-functionalized by in situ sonochemical synthesis was 1.84 emu g{sup -1}. An important finding is that obtained magnetic nanocomposite materials exhibit enhanced magnetic properties than those of iron oxide/MCM-41 nanocomposite obtained by conventional method. The described method is providing a rather short preparation time and a narrow size distribution of iron oxide nanoparticles.

  3. Preparation of copper (I) oxide nanohexagon decorated reduced graphene oxide nanocomposite and its application in electrochemical sensing of dopamine

    Energy Technology Data Exchange (ETDEWEB)

    Sivasubramanian, R., E-mail: rss@psgias.ac.in; Biji, P.

    2016-08-15

    Highlights: • Cu{sub 2}O nanohexagon–reduced graphene oxide (rGO) nanocomposite has been prepared by in-situ reduction method. • The rGO-Cu{sub 2}O/GCE exhibited excellent catalytic properties for dopamine due to the synergistic action of the nanocomposite. • The proposed sensor is highly selective toward dopamine in the presence of ascorbic acid and uric acid. - Graphical Abstract: - Abstract: An electrochemical sensor using copper (I) oxide nanostructure decorated reduced graphene oxide (rGO) nanocomposite has been proposed for selective detection of dopamine. The rGO–Cu{sub 2}O nanocomposite was synthesized by in-situ chemical reduction method and was characterized using Transmission Electron Microscope (TEM), Energy Dispersive X-ray (EDX) analysis, X-ray Diffraction (XRD) patterns, Fourier Transform Infrared (FTIR), UV–vis and Raman Spectroscopy, respectively. From Cyclic Voltammetric (CV) studies, it was inferred that rGO–Cu{sub 2}O/GCE exhibits excellent electrocatalytic activity toward dopamine, which is attributed to the enhanced conductivity as well as the synergistic effect of the nanocomposite. The sensing was carried out using Differential Pulse Voltammetry (DPV) wherefrom a Limit of Detection (LOD) of 50 nM with a linear range from 10 µM to 900 µM was estimated. The effect of potential interfering agents such as Uric Acid (UA), Ascorbic Acid (AA), glucose, K{sup +}, Na{sup +}, Cl{sup −}, and SO{sub 4}{sup −} ions toward sensing were investigated. The performance of the sensor toward the estimation of dopamine in human blood and urine samples were analyzed. The facile method for the preparation of a nanocomposite in conjunction with the low detection limit and the wide linear range for dopamine sensing is the advantage of this present study.

  4. Flexible Pressure Sensor Based on PVDF Nanocomposites Containing Reduced Graphene Oxide-Titania Hybrid Nanolayers

    Directory of Open Access Journals (Sweden)

    Aisha Al-Saygh

    2017-01-01

    Full Text Available A novel flexible nanocomposite pressure sensor with a tensile strength of about 47 MPa is fabricated in this work. Nanolayers of titanium dioxide (titania nanolayers, TNL synthesized by hydrothermal method are used to reinforce the polyvinylidene fluoride (PVDF by simple solution mixing. A hybrid composite is prepared by incorporating the TNL (2.5 wt % with reduced graphene oxide (rGO (2.5 wt % synthesized by improved graphene oxide synthesis to form a PVDF/rGO-TNL composite. A comparison between PVDF, PVDF/rGO (5 wt %, PVDF/TNL (5 wt % and PVDF/rGO-TNL (total additives 5 wt % samples are analyzed for their sensing, thermal and dielectric characteristics. The new shape of additives (with sharp morphology, good interaction and well distributed hybrid additives in the matrix increased the sensitivity by 333.46% at 5 kPa, 200.7% at 10.7 kPa and 246.7% at 17.6 kPa compared to the individual PVDF composite of TNL, confirming its possible application in fabricating low cost and light weight pressure sensing devices and electronic devices with reduced quantity of metal oxides. Increase in the β crystallinity percentage and removal of α phase for PVDF was detected for the hybrid composite and linked to the improvement in the mechanical properties. Tensile strength for the hybrid composite (46.91 MPa was 115% higher than that of the neat polymer matrix. Improvement in the wettability and less roughness in the hybrid composites were observed, which can prevent fouling, a major disadvantage in many sensor applications.

  5. Synthesis and characterization of nanocomposite powders of calcium phosphate/titanium oxide for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Delima, S.A.; Camargo, N.H.A.; Souza, J.C.P.; Gemelli, E., E-mail: sarahamindelima@hotmail.com, E-mail: dem2nhac@joinville.udesc.br, E-mail: souzajulio@joinville.udesc.br, E-mail: gemelli@joinville.udesc.br [Universidade do Estado de Santa Catarina (UDESC), Joinville, SC (Brazil). Centro de Ciencias Tecnologicas

    2009-07-01

    The nanostructured bioceramics of calcium phosphate are current themes of research and they are becoming important as bone matrix in regeneration of tissues in orthopedic and dental applications. Nanocomposite powders of calcium phosphate, reinforced with nanometric particles of titanium oxide, silica oxide and alumina oxid ealpha, are being widely studied because they offer new microstructures, nanostructures and interconnected microporosity with high superficial area of micropores that contribute to osteointegration and osteoinduction processes. This study is about the synthesis of nanocomposites powders of calcium phosphate reinforced with 1%, 2%, 3% and 5% in volume of titanium oxide and its characterization through the techniques of X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Differential Thermal Analysis (DTA), Thermogravimetry (TG) and Dilatometry. (author)

  6. Rational design of metal oxide nanocomposite anodes for advanced lithium ion batteries

    Science.gov (United States)

    Li, Yong; Yu, Shenglan; Yuan, Tianzhi; Yan, Mi; Jiang, Yinzhu

    2015-05-01

    Metal-oxide anodes represent a significant future direction for advanced lithium ion batteries. However, their practical applications are still seriously hampered by electrode disintegration and capacity fading during cycling. Here, we report a rational design of 3D-staggered metal-oxide nanocomposite electrode directly fabricated by pulsed spray evaporation chemical vapor deposition, where various oxide nanocomponents are in a staggered distribution uniformly along three dimensions and across the whole electrode. Such a special design of nanoarchitecture combines the advantages of nanoscale materials in volume change and Li+/electron conduction as well as uniformly staggered and compact structure in atom migration during lithiation/delithiation, which exhibits high specific capacity, good cycling stability and excellent rate capability. The rational design of metal-oxide nanocomposite electrode opens up new possibilities for high performance lithium ion batteries.

  7. Facile hydrothermal preparation of niobium pentaoxide decorated reduced graphene oxide nanocomposites for supercapacitor applications

    Science.gov (United States)

    Murugan, M.; Kumar, R. Mohan; Alsalme, Ali; Alghamdi, Abdulaziz; Jayavel, R.

    2016-04-01

    Facile synthesis of graphene-Nb2O5 composite has been reported. Graphene oxide was prepared by the modified Hummer's method. The metal oxide (Nb2O5) was introduced to the graphene to form the composite by the hydrothermal method. The prepared samples were characterized by X-ray diffraction, scanning electron microscopy, high resolution transmission electron microscopy, Fourier transform infrared (FTIR) and thermo gravimetric analysis (TGA). SEM and TEM results revealed that the metal oxide particles are uniformly dispersed on the surface of thin sheets of well-defined multilayered graphene structure. Thermal stability of the graphene metal oxide nanocomposites was also investigated. The CV measurements reveal a significant enhancement in the specific capacitance reaching 321 Fg-1 at a scan rate of 10 mV s-1. With promising electrochemical characteristics, Nb2O5 decorated graphene nanocomposite are explored as potential electrode material for supercapacitor applications.

  8. Anormalous Optical Absorption in Porous Al_2O3 Host Matrix---Nano-Oxide Particle Nanocomposites

    Science.gov (United States)

    Zhang, Lide; Zhang, Biao; Mo, Chimei

    1996-03-01

    Porous Al_2O3 host matrix---nano-γ-Fe_2O3 particle composites (porous nanocomposite) were prepared by pyrolysis of Fe(NO_3)_39H_2O in porous nano- Al_2O3 matrix at 250^0C. Comparing with simple nanocomposites formed by mixing nano-γ-Fe_2O3 and compacting at room temperature, followed by annealing at 250^0C, the following anomalous optical behaviors were observed: for porous nanocomposite containing 5% Fe_2O_3, the aborption edge shifts obviously from 827nm to 543nm, and with increasing dopping amount of Fe_2O3 from 5% to 70%, blue shift phenomina decreases. Namely, the absorption edge moves from 543nm to 710nm. The mechanism of shift of the absorption edge is discussed.

  9. effects of mixed of mixed of mixed alkaline earth oxides in potash ...

    African Journals Online (AJOL)

    eobe

    The aim of this work is to investigate the effects of mixed alkaline earth oxide. The aim of this ... been studied. As for the method used, raw materials were collected, batch calculations were made, and the batches ... This research work therefore ...

  10. Reduced Graphene Oxide Functionalized with Cobalt Ferrite Nanocomposites for Enhanced Efficient and Lightweight Electromagnetic Wave Absorption

    Science.gov (United States)

    Ding, Yi; Liao, Qingliang; Liu, Shuo; Guo, Huijing; Sun, Yihui; Zhang, Guangjie; Zhang, Yue

    2016-01-01

    In this paper, reduced graphene oxide functionalized with cobalt ferrite nanocomposites (CoFe@rGO) as a novel type of electromagnetic wave (EW) absorbing materials was successfully prepared by a three-step chemical method including hydrothermal synthesis, annealing process and mixing with paraffin. The effect of the sample thickness and the amount of paraffin on the EW absorption properties of the composites was studied, revealing that the absorption peaks shifted toward the low frequency regions with the increasing thickness while other conditions had little or no effect. It is found that the CoFe@rGO enhanced both dielectric losses and magnetic losses and had the best EW absorption properties and the wide wavelength coverage of the hole Ku-Band when adding only 5wt% composites to paraffin. Therefore, CoFe@rGO could be used as an efficient and lightweight EW absorber. Compared with the research into traditional absorbing materials, this figures of merit are typically of the same order of magnitude, but given the lightweight nature of the material and the high level of compatibility with mass production standards, making use of CoFe@rGO as an electromagnetic absorber material shows great potential for real product applications. PMID:27587001

  11. Green synthesis, characterization, and anticancer activity of hyaluronan/zinc oxide nanocomposite.

    Science.gov (United States)

    Namvar, Farideh; Azizi, Susan; Rahman, Heshu Sulaiman; Mohamad, Rosfarizan; Rasedee, Abdullah; Soltani, Mozhgan; Rahim, Raha Abdul

    2016-01-01

    The study describes an in situ green biosynthesis of zinc oxide nanocomposite using the seaweed Sargassum muticum water extract and hyaluronan biopolymer. The morphology and optical properties of the hyaluronan/zinc oxide (HA/ZnO) nanocomposite were determined by Fourier transform infrared spectroscopy, X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, and ultraviolet-vis analysis. Electron microscopy and X-ray diffraction analysis showed that the zinc oxide nanoparticles were polydispersed with a mean size of 10.2±1.5 nm. The nanoparticles were mostly hexagonal in crystalline form. The HA/ZnO nanocomposite showed the absorption properties in the ultraviolet zone that is ascribed to the band gap of zinc oxide nanocomposite. In the cytotoxicity study, cancer cells, pancreatic adenocarcinoma (PANC-1), ovarian adenocarcinoma (CaOV-3), colonic adenocarcinoma (COLO205), and acute promyelocytic leukemia (HL-60) cells were treated with HA/ZnO nanocomposite. At 72 hours of treatment, the half maximal inhibitory concentration (IC50) value via the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was 10.8±0.3 μg/mL, 15.4±1.2 μg/mL, 12.1±0.9 μg/mL, and 6.25±0.5 μg/mL for the PANC-1, CaOV-3, COLO-205, and HL-60 cells, respectively, showing that the composite is most toxic to the HL-60 cells. On the other hand, HA/ZnO nanocomposite treatment for 72 hours did not cause toxicity to the normal human lung fibroblast (MRC-5) cell line. Using fluorescent dyes and flow cytometry analysis, HA/ZnO nanocomposite caused G2/M cell cycle arrest and stimulated apoptosis-related increase in caspase-3 and -7 activities of the HL-60 cells. Thus, the study shows that the HA/ZnO nanocomposite produced through green synthesis has great potential to be developed into an efficacious therapeutic agent for cancers.

  12. "Raisin bun"-like nanocomposites of palladium clusters and porphyrin for superior formic acid oxidation.

    Science.gov (United States)

    Wang, Xiuxin; Yang, Jiandong; Yin, Huajie; Song, Rui; Tang, Zhiyong

    2013-05-21

    A novel "raisin bun"-like nanocomposite, where Pd clusters are embedded in porphyrin matrix, is developed as a promising electrocatalyst. Thanks to the synergy between the Pd clusters and the porphyrin matrix, this composite exhibits a low oxidation potential, high mass activity and excellent stability toward electrochemical oxidation of formic acid, which opens new routes for the design of high-performance catalysts in fuel cells. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Method of preparing graphene-sulfur nanocomposites for rechargeable lithium-sulfur battery electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Jun; Lemmon, John P; Yang, Zhenguo; Cao, Yuliang; Li, Xiaolin

    2015-04-07

    A method of preparing a graphene-sulfur nanocomposite for a cathode in a rechargeable lithium-sulfur battery comprising thermally expanding graphite oxide to yield graphene layers, mixing the graphene layers with a first solution comprising sulfur and carbon disulfide, evaporating the carbon disulfide to yield a solid nanocomposite, and grinding the solid nanocomposite to yield the graphene-sulfur nanocomposite. Rechargeable-lithium-sulfur batteries having a cathode that includes a graphene-sulfur nanocomposite can exhibit improved characteristics. The graphene-sulfur nanocomposite can be characterized by graphene sheets with particles of sulfur adsorbed to the graphene sheets. The sulfur particles have an average diameter of less than 50 nm.

  14. Preparation of graphene/vanadium oxide nanocomposite monolith and its electrochemical performance

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Lingjuan; Ma, Zhanying; Li, Xiaobo; Fan, Guang, E-mail: Chemfang@163.com

    2015-10-15

    Graphical Abstract: Graphene/V{sub 2}O{sub 5}(G/V{sub 2}O{sub 5}) nanocomposite monolith is prepared in a mixture of ammonium vanadate, acetic acid and graphite oxide by one-step hydrothermal technology. Owing to the novel structure of ultralong V{sub 2}O{sub 5} nanobelts interpenetrated between the G nanosheets, the G/V{sub 2}O{sub 5} nanocomposite electrode shows higher specific capacitances and better cycle stability than those of G and V{sub 2}O{sub 5} electrodes for supercapaciors and lithium ion battaries. - Highlights: • G/V{sub 2}O{sub 5} nanocomposite monolith is prepared by one-step hydrothermal technology. • G/V{sub 2}O{sub 5} nanocomposite electrode shows much excellent capacitive property. • G/V{sub 2}O{sub 5} nanocomposite exhibits more stable cycle performance. - Abstract: Graphene/vanadium oxide nanocomposite (G/V{sub 2}O{sub 5}) monolith is prepared via a simple hydrothermal process. Owing to the intimate contact between the V{sub 2}O{sub 5} nanobelts and graphene nanosheets in the monolith, the nanocomposite shows excellent electric conductivity, and therefore makes the electrode–electrolyte contact better and Li{sup +} diffusion faster. A high specific capacitance of 163 F g{sup −1} has been achieved for G/V{sub 2}O{sub 5} electrode in 0.5 mol L{sup −1} K{sub 2}SO{sub 4} solution. The G/V{sub 2}O{sub 5} nanocomposite exhibits excellent cyclic performance with nearly 80% capacity retention at a current density of 5 A g{sup −1} in a testing range of 1000 cycles. Moreover, G/V{sub 2}O{sub 5} nanocomposite exhibits excellent discharge properties and cycle stability as an anode material for lithium ion batteries. The initial capacity is 1100 mAh g{sup −1} and the reversible capacity of 530 mAh g{sup −1} is maintained after 100 cycles at a current density of 50 mA g{sup −1}.

  15. Reduced graphene oxide/CeO{sub 2} nanocomposite with enhanced photocatalytic performance

    Energy Technology Data Exchange (ETDEWEB)

    Kaur, Jasmeet, E-mail: jasmeet.dayal@gmail.com; Anand, Kanika; Singh, Gurpreet; Hastir, Anita; Virpal,; Singh, Ravi Chand [Laboratory For Sensors and Physics Education, Department of Physics, GND University, Amritsar-143005 (India); Anand, Kanica [Semiconductors Laboratory, Department of Physics, GND University, Amritsar– 143005 (India)

    2015-05-15

    In this work, reduced graphene oxide /cerium oxide (RGO/CeO{sub 2}) nanocomposite was synthesized by in situ reduction of cerium nitrate Ce(NO{sub 3}){sub 3}·6H{sub 2}O in the presence of graphene oxide by hydrazine hydrate (N{sub 2}H{sub 4}.H{sub 2}O). The intrinsic characteristics of as-prepared nanocomposite were studied using powder x-ray diffraction (XRD), Raman spectroscopy and field-emission scanning electron microscopy (FESEM). The photocatalytic degradation of methylene blue (MB) was employed as a model reaction to evaluate the photocatalytic activity of the RGO/CeO{sub 2} nanocomposite. The as-obtained RGO/CeO{sub 2} nanocomposite displays a significantly enhanced photocatalytic degradation of MB dye in comparison with bare CeO{sub 2} nanoparticles under sunlight irradiation, which can be attributed to the improved separation of electron-hole pairs and enhanced adsorption performance due to presence of RGO.

  16. Multifunctional zirconium oxide doped chitosan based hybrid nanocomposites as bone tissue engineering materials.

    Science.gov (United States)

    Bhowmick, Arundhati; Jana, Piyali; Pramanik, Nilkamal; Mitra, Tapas; Banerjee, Sovan Lal; Gnanamani, Arumugam; Das, Manas; Kundu, Patit Paban

    2016-10-20

    This paper reports the development of multifunctional zirconium oxide (ZrO2) doped nancomposites having chitosan (CTS), organically modified montmorillonite (OMMT) and nano-hydroxyapatite (HAP). Formation of these nanocomposites was confirmed by various characterization techniques such as Fourier transform infrared spectroscopy and powder X-ray diffraction. Scanning electron microscopy images revealed uniform distribution of OMMT and nano-HAP-ZrO2 into CTS matrix. Powder XRD study and TEM study revealed that OMMT has partially exfoliated into the polymer matrix. Enhanced mechanical properties in comparison to the reported literature were obtained after the addition of ZrO2 nanoparticle into the nanocomposites. In rheological measurements, CMZH I-III exhibited greater storage modulus (G') than loss modulus (G″). TGA results showed that these nanocomposites are thermally more stable compare to pure CTS film. Strong antibacterial zone of inhibition and the lowest minimum inhibition concentration (MIC) value of these nanocomposites against bacterial strains proved that these materials have the ability to prevent bacterial infection in orthopedic implants. Compatibility of these nanocomposites with pH and blood of human body was established. It was observed from the swelling study that the swelling percentage was increased with decreasing the hydrophobic OMMT content. Human osteoblastic MG-63 cell proliferations were observed on the nanocomposites and cytocompatibility of these nanocomposites was also established. Moreover, addition of 5wt% OMMT and 5wt% nano-HAP-ZrO2 into 90wt% CTS matrix provides maximum tensile strength, storage modulus, aqueous swelling and cytocompatibility along with strong antibacterial effect, pH and erythrocyte compatibility. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Electrochromic Performance of Nanocomposite Nickel Oxide Counter Electrodes Containing Lithium and Zirconium

    Energy Technology Data Exchange (ETDEWEB)

    Engtrakul, Chaiwat [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Lin, Feng [Formerly NREL; Colorado School of Mines; Montano, Manuel [Colorado School of Mines; Tian, Chixia [Colorado School of Mines; Ji, Yazhou [Colorado School of Mines; Nordlund, Dennis [SLAC National Accelerator Laboratory; Weng, Tsu-Chien [SLAC National Accelerator Laboratory; Moore, Rob G. [SLAC National Accelerator Laboratory; Gillaspie, Dane T. [Formerly NREL; Jones, Kim M. [Formerly NREL; Dillon, Anne C. [Formerly NREL; Richards, Ryan M. [Colorado School of Mines

    2013-12-02

    Nickel oxide materials are suitable for counter electrodes in complementary electrochromic devices. The state-of-the-art nickel oxide counter electrode materials are typically prepared with multiple additives to enhance peformance. Herein, nanocomposite nickel oxide counter electrodes were fabricated via RF magnetron co-sputtering from Ni-Zr alloy and Li2O ceramic targets. The as-deposited nanocomposite counter electrodes were characterized with inductively coupled plasma mass spectrometry (ICP-MS), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), and X-ray absorption spectroscopy (XAS). It was found that the stoichiometry, crystal structure and electronic structure of the nickel oxide-based materials could be readily tuned by varying the Li2O sputter deposition power level. Comprehensive electrochromic evaluation demonstrated that the performance of the nickel oxide-based materials was dependent on the overall Li stoichiometry. Overall, the nanocomposite nickel oxide counter electrode containing lithium and zirconium synthesized with a Li2O deposition power of 45 W exhibited the optimal performance with an optical modulation of 71% and coloration efficiency of 30 cm2/C at 670 nm in Li-ion electrolyte.

  18. Graphene oxides dispersing and hosting graphene sheets for unique nanocomposite materials.

    Science.gov (United States)

    Tian, Leilei; Anilkumar, Parambath; Cao, Li; Kong, Chang Yi; Meziani, Mohammed J; Qian, Haijun; Veca, L Monica; Thorne, Tim J; Tackett, Kenneth N; Edwards, Travis; Sun, Ya-Ping

    2011-04-26

    Graphene oxides (GOs), beyond their widely reported use as precursors for single-layer graphene sheets, are in fact excellent materials themselves (polymers in two-dimension, polyelectrolyte-like, aqueous solubility and biocompatibility, etc.). In this reported work we used aqueous GOs to effectively disperse few-layer graphene sheets (GNs) in suspension for facile wet-processing into nanocomposites of GNs embedded in GOs (as the polymeric matrix). The resulting lightweight and plastic-like nanocomposite materials remained mechanically flexible even at high loadings of GNs, and they were found to be highly efficient in thermal transport, with the experimentally determined thermal diffusivity competitive to those typically observed only in well-known thermally conductive metals such as aluminum and copper. As demonstrated, GOs apparently represent a unique class of two-dimensional polymeric materials for potentially "all-carbon" nanocomposites, among others, which may find technological applications independent of those widely proclaimed for graphene sheets.

  19. Photoluminescent zinc oxide polymer nanocomposites fabricated using picosecond laser ablation in an organic solvent

    Science.gov (United States)

    Wagener, Philipp; Faramarzi, Shamsolzaman; Schwenke, Andreas; Rosenfeld, Rupert; Barcikowski, Stephan

    2011-06-01

    Nanocomposites made of ZnO nanoparticles dispersed in thermoplastic polyurethane were synthesized using picosecond laser ablation of zinc in a polymer-doped solution of tetrahydrofuran. The pre-added polymer stabilizes the ZnO nanoparticles in situ during laser ablation by forming a polymer shell around the nanoparticles. This close-contact polymer shell has a layer thickness up to 30 nm. Analysis of ZnO polyurethane nanocomposites using optical spectroscopy, high resolution transmission electron microscopy and X-ray diffraction revealed that oxidized and crystalline ZnO nanoparticles were produced. Those nanocomposites showed a green photoluminescence emission centred at 538 nm after excitation at 350 nm, which should be attributed to oxygen defects generated during the laser formation mechanism of the monocrystalline nanoparticles. Further, the influence of pulse energy and polymer concentration on the production rate, laser fluence and energy-specific mass productivity was investigated.

  20. Hierarchical Nanocomposites of Polyaniline Nanowire Arrays on Reduced Graphene Oxide Sheets for Supercapacitors

    Science.gov (United States)

    Wang, Li; Ye, Yinjian; Lu, Xingping; Wen, Zhubiao; Li, Zhuang; Hou, Haoqing; Song, Yonghai

    2013-01-01

    Here we reported a novel route to synthesize a hierarchical nanocomposite (PANI-frGO) of polyaniline (PANI) nanowire arrays covalently bonded on reduced graphene oxide (rGO). In this strategy, nitrophenyl groups were initially grafted on rGO via C-C bond, and then reduced to aminophenyl to act as anchor sites for the growth of PANI arrays on rGO. The functionalized process was confirmed by atomic force microscopy, scanning electron microscopy, Fourier transform infrared spectroscopy, Raman spectroscopy and thermogravimetric analysis. The electrochemical properties of the PANI-frGO as supercapacitor materials were investigated. The PANI-frGO nanocomposites showed high capacitance of 590 F g−1 at 0.1 A g−1, and had no loss of capacitance after 200 cycles at 2 A g−1. The improved electrochemical performance suggests promising application of the PANI-frGO nanocomposites in high-performance supercapacitors. PMID:24356535

  1. Water-processable laponite/polyaniline/graphene oxide nanocomposites for energy applications.

    Science.gov (United States)

    Ramphal, Isaac A; Hagerman, Michael E

    2015-02-03

    Graphene-polyaniline (GP) nanocomposites have demonstrated remarkable ability as supercapacitive materials and are typically synthesized via chemical reduction of graphene oxide/polyaniline (GOP) precursors. We report the formation of novel nanomaterials combining GOP nanocomposites with Laponite nanodisks. Host-guest interactions within GOP systems were studied with and without Laponite nanoparticle templating agents. Incorporating Laponite clay into the composite synthesis enhances aqueous dispersibility as well as facilitates the casting of homogeneous films. Structural and morphological characterization confirmed porous heterointerfaces and control of polymer and nanoclay loading. These results may enable the development of flexible supercapacitive and solar nanocomposites with improved device utility, water dispersibility, and film processability. We demonstrate that these films can be easily cast and that the composites maintain their electrical transport properties.

  2. Lithium Insertion in Poly (ethylene oxide)/MoO3 Xerogel Nanocomposite Films

    Institute of Scientific and Technical Information of China (English)

    HU Yong-sheng; CHEN Wen; XU Qing; YUAN Run-zhang

    2002-01-01

    The nanocomposite films were prepared by direct intercalation of poly ( ethylene oxide ) and PEO into MoO3 xerogel via sol-gel route. The electrochromic behavior and the chemical conditions of Li + ions were investigated by cyclic voltammograms, UV-visible spectral transmittance and XPS. The results show that the cycling efficiency and the reversibility of insertion/extraction of Li+ ins in (PEO)1MoO3·nH2O nanocomposite film were improved. The intercalation of PEO into MoO3 xerogel modulated the wavelength range of electrochromism and enhanced the electrochromic efficiency. Two different chemical conditions of Li + ions existing in the interlayer and interstitial positions of MoO3 lattice were observed in MoO3 xerogel and (PEO)1 MoO3·nH2O nanocomposite films.

  3. Heterogeneous nanocomposites of silver selenide and hollow platinum nanoparticles toward methanol oxidation reaction

    Science.gov (United States)

    Cui, Penglei; He, Hongyan; Liu, Hui; Zhang, Suojiang; Yang, Jun

    2016-09-01

    Making use of the electronic coupling between different domains in composite nanomaterials is an effective way to enhance the activity of electrocatalysts. Herein, we demonstrate the preparation of nanocomposites consisting of silver selenide (Ag2Se) and platinum (Pt) nanoparticles with a hollow interior by combining the inside-out diffusion of Ag in core-shell Ag-Pt nanoparticles with the synthesis of highly active hydrophobic Se species. In specific, the Ag2Se-hPt nanocomposites are found to have superior activity and stability for methanol oxidation reaction in an acidic condition due to the strong electronic coupling effect between semiconductor and metal domains. This strategy may provide a greener and less expensive way to the large-scale synthesis of Pt-based nanocomposites, and might be used to generate other heterogeneous nanomaterials with technological importance.

  4. Graphene-zinc oxide (G-ZnO nanocomposite for electrochemical supercapacitor applications

    Directory of Open Access Journals (Sweden)

    Murugan Saranya

    2016-12-01

    Full Text Available Graphene-ZnO nanocomposites (G-ZnO were prepared by a facile solvothermal approach. Well, crystalline ZnO nanoparticles with size in the range of 30–70 nm are uniformly deposited on the graphene sheets, as evidenced by different techniques. The electrochemical properties of the prepared nanocomposites were examined by measuring the specific capacitance in 6 M KOH solution using cyclic voltammetry and galvanostatic charge–discharge techniques. G-ZnO nanocomposites showed a good capacitive behavior with a specific capacitance of 122.4 F/g as compared to graphene oxide (2.13 F/g and rGO (102.5 F/g at 5 mV/s scan rate. Results demonstrated that such hybrid materials are promising electrode materials for high-performance supercapacitor applications.

  5. Reduced Graphene Oxide/Tin-Antimony Nanocomposites as Anode Materials for Advanced Sodium-Ion Batteries.

    Science.gov (United States)

    Ji, Liwen; Zhou, Weidong; Chabot, Victor; Yu, Aiping; Xiao, Xingcheng

    2015-11-11

    Reduced graphene oxides loaded with tin-antimony alloy (RGO-SnSb) nanocomposites were synthesized through a hydrothermal reaction and the subsequent thermal reduction treatments. Transmission electron microscope images confirm that SnSb nanoparticles with an average size of about 20-30 nm are uniformly dispersed on the RGO surfaces. When they were used as anodes for rechargeable sodium (Na)-ion batteries, these as-synthesized RGO-SnSb nanocomposite anodes delivered a high initial reversible capacity of 407 mAh g(-1), stable cyclic retention for more than 80 cycles and excellent cycle stability at ultra high charge/discharge rates up to 30C. The significantly improved performance of the synthesized RGO-SnSb nanocomposites as Na-ion battery anodes can be attributed to the synergetic effects of RGO-based flexible framework and the nanoscale dimension of the SnSb alloy particles (batteries.

  6. Graphitic carbon nitride/graphene oxide/reduced graphene oxide nanocomposites for photoluminescence and photocatalysis

    Science.gov (United States)

    Aleksandrzak, Malgorzata; Kukulka, Wojciech; Mijowska, Ewa

    2017-03-01

    The study presents a modification of graphitic carbon nitride (g-C3N4) with graphene oxide (GO) and reduced graphene oxide (rGO) and investigation of photoluminescent and photocatalytic properties. The influence of GO and rGO lateral sizes used for the modification was investigated. The nanomaterials were characterized with atomic force microscopy (AFM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), diffuse reflectance UV-vis spectroscopy (DR-UV-vis) and photoluminescence spectroscopy (PL). PL revealed that pristine graphitic carbon nitride and its nanocomposites with GO and rGO emitted up-converted photoluminescence (UCPL) which could contribute to the improvement of photocatalytic activity of the materials. The photoactivity was evaluated in a process of phenol decomposition under visible light. A hybrid composed of rGO nanoparticles (rGONPs, 4-135 nm) exhibited the highest photoactivity compared to rGO with size of 150 nm-7.2 μm and graphene oxide with the corresponding sizes. The possible reason of the superior photocatalytic activity is the most enhanced UCPL of rGONPs, contributing to the emission of light with higher energy than the incident light, resulting in improved photogeneration of electron-hole pairs.

  7. Development of bone-like zirconium oxide nanoceramic modified chitosan based porous nanocomposites for biomedical application.

    Science.gov (United States)

    Bhowmick, Arundhati; Pramanik, Nilkamal; Jana, Piyali; Mitra, Tapas; Gnanamani, Arumugam; Das, Manas; Kundu, Patit Paban

    2017-02-01

    Here, zirconium oxide nanoparticles (ZrO2 NPs) were incorporated for the first time in organic-inorganic hybrid composites containing chitosan, poly(ethylene glycol) and nano-hydroxypatite (CS-PEG-HA) to develop bone-like nanocomposites for bone tissue engineering application. These nanocomposites were characterized by FT-IR, XRD, TEM combined with SAED. SEM images and porosity measurements revealed highly porous structure having pore size of less than 1μm to 10μm. Enhanced water absorption capacity and mechanical strengths were obtained compared to previously reported CS-PEG-HA composite after addition of 0.1-0.3wt% of ZrO2 NPs into these nanocomposites. The mechanical strengths and porosities were similar to that of human spongy bone. Strong antimicrobial effects against gram-negative and gram-positive bacterial strains were also observed. Along with getting low alkalinity pH (7.4) values, similar to the pH of human plasma, hemocompatibility and cytocompatibility with osteoblastic MG-63 cells were also established for these nanocomposites. Addition of 15wt% HA-ZrO2 (having 0.3wt% ZrO2 NPs) into CS-PEG (55:30wt%) composite resulted in greatest mechanical strength, porosity, antimicrobial property and cytocompatibility along with suitable water absorption capacity and compatibility with human pH and blood. Thus, this nanocomposite could serve as a potential candidate to be used for bone tissue engineering.

  8. Crystallization and unusual rheological behavior in poly(ethylene oxide)–clay nanocomposites

    KAUST Repository

    Kelarakis, Antonios

    2011-05-01

    We report a systematic study of the crystallization and rheological behavior of poly(ethylene oxide) (PEO)-clay nanocomposites. To that end a series of nanocomposites based on PEOs of different molecular weight (103 < MW < 105 g/mol) and clay surface modifier was synthesized and characterized. Incorporation of organoclays with polar (MMT-OH) or aromatic groups (MMT-Ar) suppresses the crystallization of polymer chains in low MW PEO, but does not significantly affect the crystallization of high MW matrices. In addition, the relative complex viscosity of the nanocomposites based on low MW PEO increases significantly, but the effect is less pronounced at higher MWs. The viscosity increases in the series MMT-Alk < MMT-OH < MMT-Ar. In contrast to the neat PEO which exhibits a monotonic decrease of viscosity with temperature, all nanocomposites show an increase after a certain temperature. This is the first report of such dramatic enhancements in the viscoelasticity of nanocomposites, which are reversible, are based on a simple polymer matrix and are true in a wide temperature range. © 2011 Elsevier Ltd. All rights reserved.

  9. Design and development of anisotropic inorganic/polystyrene nanocomposites by surface modification of zinc oxide nanoparticles.

    Science.gov (United States)

    Han, Xiao; Huang, Shiming; Wang, Yilong; Shi, Donglu

    2016-07-01

    Anisotropic yolk/shell or Janus inorganic/polystyrene nanocomposites were prepared by combining miniemulsion polymerization and sol-gel reaction. The morphologies of the anisotropic composites were found to be greatly influenced by surface modification of zinc oxide (ZnO) nanoparticle seeds. Two different types of the oleic acid modified ZnO nanoparticles (OA-ZnO) were prepared by post-treatment of commercial ZnO powder and homemade OA-ZnO nanoparticles. The morphologies and properties of the nanocomposites were investigated by transmission electron microscope (TEM), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), dynamic light scattering (DLS), and energy dispersive X-ray spectroscopy (EDX). It was found that both post-treated OA-ZnO and in-situ prepared OA-ZnO nanoparticles resulted in the yolk-shell and Janus structure nanocomposites, but with varied size and morphology. These nanocomposites showed stable and strong fluorescence by introducing quantum dots as the co-seeds. The fluorescent anisotropic nanocomposites were decorated separately with surface carboxyl and hydroxyl groups. These composites with unique anisotropic properties will have high potential in biomedical applications, particularly in bio-detection.

  10. Synthesis of chitosan/graphene oxide nanocomposites for methylene blue adsorption

    Science.gov (United States)

    Huyen, Nguyen Thi My; Trang, Pham Thi Thuy; Dat, Nguyen Minh; Hieu, Nguyen Huu

    2017-09-01

    In this paper, chitosan (CTS) with molecular weight (Mw) ˜810 kDa and degree of deacetylation (DDA) ˜83% was synthesized from prawns shell. Graphene oxide (GO) was prepared by improved Hummers method. CTS/GO nanocomposites were lyophilized using aldehyde formic as a cross-linked to obtain the hydrogels. The hydrogels were freeze dried to make CTS/GO nanocomposite. Characterizations of the CTS/GO nanocomposites were performed by Fourier transform infrared spectroscopy, transmission electron microscopy, X-ray diffraction, and Brunauer-Emmett-Teller specific surface area. Additionally, the effects of pH, contact time, and initial concentration on adsorption for methylene blue (MB) were investigated. The results showed that the CTS/GO nanocomposites were found to be good adsorbent for MB with a maximum adsorption capacity of 662.25 mg/g according to the Langmuir isotherm model. The adsorption data could be well described by pseudo-second-order model. After the adsorption, CTS/GO nanocomposite was easily recovered by filtration or low speed centrifugation. Accordingly, this study demonstrates potential CTS/GO adsorbent for the removal of MB from aqueous solution.

  11. Understanding the adsorptive and photoactivity properties of Ag-graphene oxide nanocomposites.

    Science.gov (United States)

    Martínez-Orozco, R D; Rosu, H C; Lee, Soo-Wohn; Rodríguez-González, V

    2013-12-15

    Nanocomposites of graphene oxide (GO) and silver nanoparticles (AgNPs) were synthetized using a practical photochemical silver functionalization. Their photocatalytic activities were evaluated with two dyes, Rhodamine B and Indigo Carmine, under visible-light irradiation. The prepared nanocomposites were characterized by HRTEM, FESEM, XRD, Raman, FTIR and UV-vis absorption spectroscopy. These nanocomposites present new defect domains of sp(3) type in combination with several graphitic functional groups that act as nucleation sites for anchoring AgNPs, while the sp(2)-sp(3) edge defects domains of GO generate the photoactivity. Furthermore, their photocatalytic performances are governed by their large adsorption capacity, and strong interaction with dye chromophores. A comprehensive photocatalytic way underlying the importance of adsorption is suggested to explain the low visible-light responsive photoactivity of the AgNPs-GO nanocomposites and the possible binding-site saturation. Then, the usage of H2SO4 allows the production of ionic species and helps to confirm the strong adsorption of both dyes. The ability to synthesize AgNPs-GO nanocomposites with extensive adsorptive capacity is certainly of interest for the efficient removal of hazardous materials.

  12. Facile hydrothermal preparation of titanium dioxide decorated reduced graphene oxide nanocomposite

    Directory of Open Access Journals (Sweden)

    Chang BYS

    2012-07-01

    Full Text Available Betty Yea Sze Chang,1 Nay Ming Huang,1 Mohd Nor An' amt,2 Abdul Rahman Marlinda,1 Yusoff Norazriena,1 Muhamad Rasat Muhamad,3 Ian Harrison,4 Hong Ngee Lim,5 Chin Hua Chia61Low Dimensional Materials Research Center, Physics Department, University of Malaya, Kuala Lumpur; 2Faculty of Agro Industry and Natural Resources (FASA, Universiti Malaysia Kelantan, Kota Bharu, Kelantan; 3The Chancellery Building, Multimedia University, Persiaran Multimedia, Cyberjaya, Selangor; 4School of Chemical and Environmental Engineering, The University of Nottingham Malaysia Campus, Semenyih, Selangor; 5Department of Chemistry, Faculty of Science, Universiti Putra Malaysia, Serdang, Selangor, Malaysia; 6School of Applied Physics, Universiti Kebangsaan Malaysia, Bangi, Selangor, MalaysiaAbstract: A simple single-stage approach, based on the hydrothermal technique, has been introduced to synthesize reduced graphene oxide/titanium dioxide nanocomposites. The titanium dioxide nanoparticles are formed at the same time as the graphene oxide is reduced to graphene. The triethanolamine used in the process has two roles. It acts as a reducing agent for the graphene oxide as well as a capping agent, allowing the formation of titanium dioxide nanoparticles with a narrow size distribution (~20 nm. Transmission electron micrographs show that the nanoparticles are uniformly distributed on the reduced graphene oxide nanosheet. Thermogravimetric analysis shows the nanocomposites have an enhanced thermal stability over the original components. The potential applications for this technology were demonstrated by the use of a reduced graphene oxide/titanium dioxide nanocomposite-modified glassy carbon electrode, which enhanced the electrochemical performance compared to a conventional glassy carbon electrode when interacting with mercury(II ions in potassium chloride electrolyte.Keywords: graphene oxide, titanium oxide, hydrothermal, nanocomposite

  13. Apoptosis inducing ability of silver decorated highly reduced graphene oxide nanocomposites in A549 lung cancer

    Directory of Open Access Journals (Sweden)

    Khan M

    2016-03-01

    Full Text Available Merajuddin Khan,1 Mujeeb Khan,1 Abdulhadi H Al-Marri,1 Abdulrahman Al-Warthan,1 Hamad Z Alkhathlan,1 Mohammed Rafiq H Siddiqui,1 Vadithe Lakshma Nayak,2 Ahmed Kamal,2 Syed F Adil1 1Department of Chemistry, College of Science, King Saud University, Riyadh, Kingdom of Saudi Arabia; 2Department of Medicinal Chemistry and Pharmacology, CSIR – Indian Institute of Chemical Technology, Hyderabad, India Abstract: Recently, graphene and graphene-based materials have been increasingly used for various biological applications due to their extraordinary physicochemical properties. Here, we demonstrate the anticancer properties and apoptosis-inducing ability of silver doped highly reduced graphene oxide nanocomposites synthesized by employing green approach. These nano­composites (PGE-HRG-Ag were synthesized by using Pulicaria glutinosa extract (PGE as a reducing agent and were evaluated for their anticancer properties against various human cancer cell lines with tamoxifen as the reference drug. A correlation between the amount of Ag nanoparticles on the surface of highly reduced graphene oxide (HRG and the anticancer activity of nanocomposite was observed, wherein an increase in the concentration of Ag nanoparticles on the surface of HRG led to the enhanced anticancer activity of the nanocomposite. The nanocomposite PGE-HRG-Ag-2 exhibited more potent cytotoxicity than standard drug in A549 cells, a human lung cancer cell line. A detailed investigation was undertaken and Fluorescence activated cell sorting (FACS analysis demonstrated that the nanocomposite PGE-HRG-Ag-2 showed G0/G1 phase cell cycle arrest and induced apoptosis in A549 cells. Studies such as, measurement of mitochondrial membrane potential, generation of reactive oxygen species (ROS and Annexin V-FITC staining assay suggested that this compound induced apoptosis in human lung cancer cells. Keywords: plant extract, graphene/silver nanocomposites, anticancer, apoptosis

  14. Hydrothermal preparation of reduced graphene oxide-silver nanocomposite using Plectranthus amboinicus leaf extract and its electrochemical performance.

    Science.gov (United States)

    Zheng, Yuhong; Wang, Aiwu; Cai, Wen; Wang, Zhong; Peng, Feng; Liu, Zhong; Fu, Li

    2016-12-01

    Graphene based nanocomposites are receiving increasing attention in many fields such as material chemistry, environmental science and pharmaceutical science. In this study, a facial synthesis of a reduced graphene oxide-silver nanocomposite (RGO-Ag) was carried out from Plectranthus amboinicus leaf extract. The synthesized nanocomposite was characterized by using X-ray diffraction, scanning electron microscope, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscope and UV-vis spectroscopy for structural confirmation. The reduction of graphene oxide and silver ions was achieved simultaneously due to the reducibility of the Plectranthus amboinicus leaf extract. We further investigated the electrochemical properties of the biosynthesized RGO-Ag nanocomposite. A nonenzymatic H2O2 electrochemical sensor was shown to be successfully fabricated by using biosynthesized RGO-Ag nanocomposite. Moreover, the fabricated electrochemical sensor also showed good selectivity.

  15. Impedance spectroscopy studies in cobalt ferrite-reduced graphene oxide nanocomposite

    Energy Technology Data Exchange (ETDEWEB)

    Supriya, Sweety, E-mail: sweety@iitp.ac.in; Kumar, Sunil, E-mail: sunil.pph13@iitp.ac.in; Kar, Manoranjan, E-mail: mano@iitp.ac.in [Department of Physics, Indian Institute of Technology Patna, Bihta-801103 (India)

    2016-05-06

    (1-x)Cobalt ferrite-(x)reduced graphene oxidenanocomposites with x=0, 0.1, 0.2 and 0.3 were prepared by the ultrasonic method. The crystal symmetry modification due to reduced graphene oxide and cobalt ferrite interaction has been studied by employing the X-ray diffraction technique. Morphology of the samples was studied by the Field emission scanning electron microscopy (FE-SEM). Study on electrical properties of the cobalt ferrite-reduced graphene oxide nanocomposites explores the possible application of these composites as anode material. Impedance decreases with an increase in frequency as well as temperature, which supports an increase in ac electrical conductivity. The modified Debye relaxation model can explain the behavior of impedance in cobalt ferrite-reduced graphene oxide nanocomposites.

  16. Liquid crystalline polymer nanocomposites reinforced with in-situ reduced graphene oxide

    Directory of Open Access Journals (Sweden)

    D. Pedrazzoli

    2015-08-01

    Full Text Available In this work liquid-crystalline polymer (LCP nanocomposites reinforced with in-situ reduced graphene oxide are investigated. Graphene oxide (GO was first synthesized by the Hummers method, and the kinetics of its thermal reduction was assessed. GO layers were then homogeneously dispersed in a thermotropic liquid crystalline polymer matrix (Vectran®, and an in-situ thermal reduction of GO into reduced graphene oxide (rGO was performed. Even at low rGO amount, the resulting nanocomposites exhibited an enhancement of both the mechanical properties and the thermal stability. Improvements of the creep stability and of the thermo-mechanical behavior were also observed upon nanofiller incorporation. Furthermore, in-situ thermal reduction of the insulating GO into the more electrically conductive rGO led to an important surface resistivity decrease in the nanofilled samples.

  17. Evaluation of poly (vinyl alcohol) based cryogel–zinc oxide nanocomposites for possible applications as wound dressing materials

    Energy Technology Data Exchange (ETDEWEB)

    Chaturvedi, Archana [Bose Memorial Research Laboratory, Department of Chemistry, Government Autonomous Science College Jabalpur (India); Bajpai, Anil K., E-mail: akbmrl@yahoo.co.in [Bose Memorial Research Laboratory, Department of Chemistry, Government Autonomous Science College Jabalpur (India); Bajpai, Jaya [Bose Memorial Research Laboratory, Department of Chemistry, Government Autonomous Science College Jabalpur (India); Singh, Sunil K. [Department of Chemistry, Guru Ghasidas University, Bilaspur, CG (India)

    2016-08-01

    In this investigation cryogels composed of poly (vinyl alcohol) (PVA) were prepared by repeated freeze thaw method followed by in situ precipitation of zinc oxide nanoparticles within the cryogel networks. Fourier transformed infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD), Energy dispersive X-ray spectroscopy (EDX) were used to characterize the nanocomposites. The morphologies of native PVA cryogels and PVA cryogel-ZnO nanocomposites were observed by scanning electron microscopy (SEM), transmission electron microscopy (TEM) techniques. The SEM analysis suggested that cryogels show a well-defined porous morphology whereas TEM micrographs revealed the presence of nearly spherical and well separated zinc oxide nanoparticles with diameter < 100 nm. XRD results showed all relevant Bragg's reflections for crystal structure of zinc oxide nanoparticles. Thermo gravimetric-differential thermal analysis (TG-DTA) was conducted to evaluate thermal stability of the nanocomposites. Mechanical properties of nanocomposites were determined in terms of tensile strength and percent elongation. Biocompatible nature was ascertained by anti-haemolytic activity, bovine serum albumin (blood protein) adsorption and in vitro cytotoxicity tests. The prepared nanocomposites were also investigated for swelling and deswelling behaviours. The results revealed that both the swelling and deswelling process depend on the chemical composition of the nanocomposites, number of freeze-thaw cycles, pH and temperature of the swelling medium. The developed biocompatible PVA cryogel-ZnO nanocomposites were also tested for antibacterial activities against both Gram-negative and Gram-positive bacteria. - Highlights: • PVA–zinc oxide nanocomposites have been prepared with no chemical crosslinking. • The nanocomposites are completely biocompatible. • They also show antibacterial property. • The nanocomposites

  18. Development of bimetal oxide doped multifunctional polymer nanocomposite for water treatment

    Science.gov (United States)

    Saxena, Swati; Saxena, Umesh

    2016-08-01

    Bimetal oxide doped polymer nanocomposite was developed using Alumina and Iron (III) Oxide as nanoparticles with Nylon 6, 6 and Poly (sodium-4-styrenesulphonate) as polymer matrix for removal of pollutants from water. The blend sample of polymers was prepared by well established solution blending technique and their nanocomposite samples were prepared through dispersion technique during the solution casting of blend sample. The fabricated composites were characterized adopting FTIR, XRD, FESEM and EDX techniques. XRD and FESEM were used for morphological characterization of nano phase, while FTIR and EDX analysis were adopted for characterization of chemical moieties in composites. In the study of pollutant removal capacities of prepared composites, 6 % nanocomposite provided the best results. It exhibited the maximum removal of all parameters. The removal of total alkalinity was 66.67 %, total hardness 42.85 %, calcium 66.67 %, magnesium 25 %, chloride 58.66 %, nitrate 34.78 %, fluoride 63.85 %, TDS 41.27 % and EC was up to the level of 41.37 % by this composite. The study is a step towards developing multifunctional, cost-effective polymer nanocomposites for water remediation applications.

  19. A Facile Route to Metal Oxides/Single-Walled Carbon Nanotube Macrofilm Nanocomposites for Energy Storage

    Directory of Open Access Journals (Sweden)

    Zeyuan eCao

    2015-05-01

    Full Text Available Nanocomposites consisting of transition-metal oxides and carbon nanomaterials with a desired size and structure are highly demanded for high performance energy storage devices. Here, a facile two-step and cost-efficient approach relying on directly thermal treatment of chemical-vapor-deposition products is developed as a general synthetic method to prepare a family of metal oxides (MxOy (M=Fe, Co, Ni/single-walled carbon nanotube (SWNT macrofilm nanocomposites. The MxOy nanoparticles obtained are of 3-17 nm in diameter and homogeneously anchor on the free-standing SWNT macrofilms. NiO/SWNT also exhibits a high specific capacitance of 400 F g-1 and fast charge-transfer Faradaic redox reactions to achieve asymmetric supercapacitors with a high power and energy density. All MxOy/SWNT nanocomposites could deliver a high capacity beyond 1000 mAh g-1 and show excellent cycling stability for lithium-ion batteries. The impressive results demonstrate the promise for energy storage devices and the general approach may pave the way to synthesize other functional nanocomposites.

  20. Analytical chemistry methods for mixed oxide fuel, March 1985

    Energy Technology Data Exchange (ETDEWEB)

    1985-03-01

    This standard provides analytical chemistry methods for the analysis of materials used to produce mixed oxide fuel. These materials are ceramic fuel and insulator pellets and the plutonium and uranium oxides and nitrates used to fabricate these pellets.

  1. Polyurethane Nanocomposites Containing Reduced Graphene Oxide, FTIR, Raman, and XRD Studies

    Directory of Open Access Journals (Sweden)

    Michał Strankowski

    2016-01-01

    Full Text Available Recently, graphene and other graphene-based materials have become an essential part of composite science and technology. Their unique properties are not only restricted to graphene but also shared with derivative compounds like graphene oxide, reduced graphene oxide, functionalized graphene, and so forth. One of the most structurally important materials, graphene oxide (GO, is prepared by the oxidation of graphite. Though removal of the oxide groups can create vacancies and structural defects, reduced graphene oxide (rGO is used in composites as effective filler similar to GO. Authors developed a new polyurethane nanocomposite using a derivative of grapheme, thermally reduced graphene oxide (rGO, to modify the matrix of polyurethane elastomers, by rGO.

  2. Morphology, thermal, mechanical, and barrier properties of graphene oxide/poly(lactic acid) nanocomposite films

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seong Woo; Choi, Hyun Muk [Kyonggi University, Suwon (Korea, Republic of)

    2016-01-15

    To improve the physical and gas barrier properties of biodegradable poly(lactic acid) (PLA) film, two graphene nanosheets of highly functionalized graphene oxide (0.3 wt% to 0.7 wt%) and low-functionalized graphene oxide (0.5 wt%) were incorporated into PLA resin via solution blending method. Subsequently, we investigated the effects of material parameters such as loading level and degree of functionalization for the graphene nanosheets on the morphology and properties of the resultant nanocomposites. The highly functionalized graphene oxide (GO) caused more exfoliation and homogeneous dispersion in PLA matrix as well as more sustainable suspensions in THF, compared to low-functionalized graphene oxide (LFGO). When loaded with GO from 0.3 wt% to 0.7 wt%, the glass transition temperature, degree of crystallinity, tensile strength and modulus increased steadily. The GO gave rise to more pronounced effect in the thermal and mechanical reinforcement, relative to LFGO. In addition, the preparation of fairly transparent PLA-based nanocomposite film with noticeably improved barrier performance achieved only when incorporated with GO up to 0.7wt%. As a result, GO may be more compatible with hydrophilic PLA resin, compared to LFGO, resulting in more prominent enhancement of nanocomposites properties.

  3. Dielectric Properties of Reduced Graphene Oxide/Copper Phthalocyanine Nanocomposites Fabricated Through π- π Interaction

    Science.gov (United States)

    Wang, Zicheng; Wei, Renbo; Liu, Xiaobo

    2017-01-01

    Reduced graphene oxide/copper phthalocyanine nanocomposites are successfully prepared through a simple and effective two-step method, involving preferential reduction of graphene oxide and followed by self-assembly with copper phthalocyanine. The results of photographs, ultraviolet visible, x-ray diffraction, x-ray photoelectron spectroscopy, and scanning electron microscopy show that the in situ blending method can effectively facilitate graphene sheets to disperse homogenously in the copper phthalocyanine matrix through π- π interactions. As a result, the reduction of graphene oxide and restoration of the sp 2 carbon sites in graphene can enhance the dielectric properties and alternating current conductivity of copper phthalocyanine effectively.

  4. Graphite oxide incorporated crosslinked polyvinyl alcohol and sulfonated styrene nanocomposite membrane as separating barrier in single chambered microbial fuel cell

    Science.gov (United States)

    Rudra, Ruchira; Kumar, Vikash; Pramanik, Nilkamal; Kundu, Patit Paban

    2017-02-01

    Different membranes with varied molar concentrations of graphite oxide (GO), 'in situ' polymerized sulfonated polystyrene (SS) and glutaraldehyde (GA) cross linked polyvinyl alcohol (PVA), have been analyzed as an effective and low cost nanocomposite barrier in single chambered microbial fuel cells (MFCs). The synthesized composite membranes, namely GO0.2, GO0.4 and GO0.6 exhibited comparatively better results with reduced water uptake (WU) and swelling ratios (SR) over the native PVA. The variation in properties is illustrated with membrane analyses, where GO0.4 showed an increased proton conductivity (PC) and ion exchange capacity (IEC) of 0.128 S cm-1 and 0.33 meq g-1 amongst all of the used membranes. In comparison, reduced oxygen diffusivity with lower water uptake showed a two-fold decrease in GO0.4 over pure PVA membrane (∼2.09 × 10-4 cm s-1). A maximum power density of 193.6 mW m-2 (773.33 mW m-3) with a current density of 803.33 mA m-2 were observed with GO0.4 fitted MFC, where ∼81.89% of chemical oxygen demand (COD) was removed using mixed firmicutes, as biocatalyst, in 25 days operation. In effect, the efficacy of GO incorporated crosslinked PVA and SS nanocomposite membrane has been evaluated as a polymer electrolyte membrane for harnessing bio-energy from single chambered MFCs.

  5. A Controllable Synthetic Route for Preparing Graphene-Cu and Graphene-Cu2O Nanocomposites Using Graphene Oxide-CuO as a Precursor

    Institute of Scientific and Technical Information of China (English)

    CHEN Li; ZHU Junwu; BI Huiping; MENG Xiaoqian; YAO Pengcheng; HAN Qiaofeng

    2015-01-01

    The development of convenient method to obtain graphene-based nanocomposites is a key issue for their application. Herein, we described a facile route for synthesizing graphene-Cu and graphene-Cu2O nanocomposites using graphene oxide-CuO as a precursor. Remarkably, the different nanocomposites could be formed just by varying the reaction temperature and time. This work provides a feasible route for the preparation of graphene-based nanocomposites with various constituents.

  6. Critical Enhancement of Photothermal Effect by Integrated Nanocomposites of Gold Nanorods and Iron Oxide on Graphene Oxide

    Energy Technology Data Exchange (ETDEWEB)

    Yun, Kumhee; Seo, Sunhwa; Kim, Bomi; Joe, Ara; Han, Hyowon; Jang, Euesoon [Kumoh National Institute of Technology, Gumi (Korea, Republic of); Kim, Jongyoung [Korea Institute of Ceramic Engineering and Technology, Icheon (Korea, Republic of)

    2013-09-15

    Irradiation of gold nanorods (GNRs) with laser light corresponding to the longitudinal surface plasmon oscillation results in rapid conversion of electromagnetic energy into heat, a phenomenon commonly known as the photothermal effect of GNRs. Herein, we propose a facile strategy for increasing the photothermal conversion efficiency of GNRs by integration to form graphene oxide (GO) nanocomposites. Moreover, conjugation of iron oxide (IO) with the GO-GNR nanohybrid allowed magnetic enrichment at a specific target site and the separated GO-IO-GNR assembly was rapidly heated by laser irradiation. The present GO-IO-GNR nanocomposites hold great promise for application in various biomedical fields, including surface enhanced Raman spectroscopy imaging, photoacoustic tomography imaging, magnetic resonance imaging, and photothermal cancer therapy.

  7. Pulicaria glutinosa extract: a toolbox to synthesize highly reduced graphene oxide-silver nanocomposites.

    Science.gov (United States)

    Al-Marri, Abdulhadi H; Khan, Mujeeb; Khan, Merajuddin; Adil, Syed F; Al-Warthan, Abdulrahman; Alkhathlan, Hamad Z; Tremel, Wolfgang; Labis, Joselito P; Siddiqui, Mohammed Rafiq H; Tahir, Muhammad N

    2015-01-05

    A green, one-step approach for the preparation of graphene/Ag nanocomposites (PE-HRG-Ag) via simultaneous reduction of both graphene oxide (GRO) and silver ions using Pulicaria glutinosa plant extract (PE) as reducing agent is reported. The plant extract functionalizes the surfaces of highly reduced graphene oxide (HRG) which helps in conjugating the Ag NPs to HRG. Increasing amounts of Ag precursor enhanced the density of Ag nanoparticles (NPs) on HRG. The preparation of PE-HRG-Ag nanocomposite is monitored by using ultraviolet-visible (UV-Vis) spectroscopy, powder X-ray diffraction (XRD), and energy dispersive X-ray (EDX). The as-prepared PE-HRG-Ag nanocomposities display excellent surface-enhanced Raman scattering (SERS) activity, and significantly increased the intensities of the Raman signal of graphene.

  8. Pulicaria glutinosa Extract: A Toolbox to Synthesize Highly Reduced Graphene Oxide-Silver Nanocomposites

    Directory of Open Access Journals (Sweden)

    Abdulhadi H. Al-Marri

    2015-01-01

    Full Text Available A green, one-step approach for the preparation of graphene/Ag nanocomposites (PE-HRG-Ag via simultaneous reduction of both graphene oxide (GRO and silver ions using Pulicaria glutinosa plant extract (PE as reducing agent is reported. The plant extract functionalizes the surfaces of highly reduced graphene oxide (HRG which helps in conjugating the Ag NPs to HRG. Increasing amounts of Ag precursor enhanced the density of Ag nanoparticles (NPs on HRG. The preparation of PE-HRG-Ag nanocomposite is monitored by using ultraviolet–visible (UV-Vis spectroscopy, powder X-ray diffraction (XRD, and energy dispersive X-ray (EDX. The as-prepared PE-HRG-Ag nanocomposities display excellent surface-enhanced Raman scattering (SERS activity, and significantly increased the intensities of the Raman signal of graphene.

  9. Evaluation of dosimetric characteristics of graphene oxide/PVC nanocomposite for gamma radiation applications

    Energy Technology Data Exchange (ETDEWEB)

    Feizi, Shahzad; Malekie, Shahryar; Ziaie, Farhood [Nuclear Science and Technology Research Institute (NSTRI), Karaj (Iran, Islamic Republic of). Radiation Application Research School; Rahighi, Reza; Tayyebi, Ahmad [Univ. of Technology, Tehran (Iran, Islamic Republic of). Dept. of Physics

    2017-04-01

    Graphene oxide-polyvinyl chloride composite was prepared using tetrahydrofuran solvent-assisted dispersion of characterized nano flakes of graphene oxide in polymer matrix. Electrical percolation threshold of GO/PVC nanocomposite was determined via a finite element simulation method with a 2D model and compared with experimental results. A conductive cell with two silver coated walls was designed and fabricated for exploring dosimetric properties of the composite. Some characteristics of the new nanocomposite such as linearity of dose response, repeatability, sensitivity and angular dependence are investigated. According to 2D proposed method, obtained data associated to electrical conductivity of the GO/polymer composite for PVC matrix plotted in different GO weight percentages and had good compatibility (validity) with experimental data. The dose response is linear in the 17-51 mGy dose range and it can be introduced for gamma radiation dosimetry in diagnostic activities.

  10. Graphene oxide-silver nanocomposite as a promising biocidal agent against methicillin-resistant Staphylococcus aureus.

    Science.gov (United States)

    de Moraes, Ana Carolina Mazarin; Lima, Bruna Araujo; de Faria, Andreia Fonseca; Brocchi, Marcelo; Alves, Oswaldo Luiz

    2015-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) has been responsible for serious hospital infections worldwide. Nanomaterials are an alternative to conventional antibiotic compounds, because bacteria are unlikely to develop microbial resistance against nanomaterials. In the past decade, graphene oxide (GO) has emerged as a material that is often used to support and stabilize silver nanoparticles (AgNPs) for the preparation of novel antibacterial nanocomposites. In this work, we report the synthesis of the graphene-oxide silver nanocomposite (GO-Ag) and its antibacterial activity against relevant microorganisms in medicine. GO-Ag nanocomposite was synthesized through the reduction of silver ions (Ag(+)) by sodium citrate in an aqueous GO dispersion, and was extensively characterized using ultraviolet-visible absorption spectroscopy, X-ray diffraction, thermogravimetric analysis, X-ray photoelectron spectroscopy, and transmission electron microscopy. The antibacterial activity was evaluated by microdilution assays and time-kill experiments. The morphology of bacterial cells treated with GO-Ag was investigated via transmission electron microscopy. AgNPs were well distributed throughout GO sheets, with an average size of 9.4±2.8 nm. The GO-Ag nanocomposite exhibited an excellent antibacterial activity against methicillin-resistant S. aureus, Acinetobacter baumannii, Enterococcus faecalis, and Escherichia coli. All (100%) MRSA cells were inactivated after 4 hours of exposure to GO-Ag sheets. In addition, no toxicity was found for either pristine GO or bare AgNPs within the tested concentration range. Transmission electronic microscopy images offered insights into how GO-Ag nanosheets interacted with bacterial cells. Our results indicate that the GO-Ag nanocomposite is a promising antibacterial agent against common nosocomial bacteria, particularly antibiotic-resistant MRSA. Morphological injuries on MRSA cells revealed a likely loss of viability as a result of the

  11. Design of a new nanocomposite between bismuth nanoparticles and graphene oxide for development of electrochemical sensors.

    Science.gov (United States)

    Bindewald, Eduardo H; Schibelbain, Arthur F; Papi, Maurício A P; Neiva, Eduardo G C; Zarbin, Aldo J G; Bergamini, Márcio F; Marcolino-Júnior, Luiz H

    2017-10-01

    This study describes a new route for preparation of a nanocomposite between graphene oxide (GO) and bismuth nanoparticles (BiNPs) and its evaluation as modifier electrode for development of electrochemical sensors. BiNPs were synthesized under ultrasound conditions using Bi(NO3)3 as metal precursor and ascorbic acid (AA) as reducing agent/passivating. Some experimental parameters of BiNPs synthesis such as Bi(3+):AA molar ratio and reaction time were conducted aiming the best voltammetric performance of the sensor. Glassy carbon electrodes (GCE) were modified by drop-casting with the BiNPs dispersions and anodic stripping voltammetry measurements were performed and revealed an improvement in the sensitivityfor determination of Cd(II) and Pb(II) compared to an unmodified electrode. The best electrochemical response was obtained for a BiNPs synthesis with Bi(3+):AA molar ratio of 1:6 and reaction time of 10min, which yielded Bi metallic nanoparticles with average size of 5.4nm confirmed by XRD and TEM images, respectively. GO was produced by graphite oxidation using potassium permanganate and exfoliated with an ultrasound tip. GO-BiNPs nanocomposite was obtained by a simple mixture of GO and BiNPs dispersions in water and kept under ultrasonic bath for 1h. GCE were modified with a nanocomposite suspension containing 0.3 and 1.5mgmL(-1) of GO and BiNPs in water, respectively. Under optimized conditions, the proposed nanocomposite was evaluated on the voltammetric determination of Pb (II) and Cd (II), leading to a linear response range between 0.1 and 1.4μmolL(-1) for both cations, with limit of detection of 30 and 27nmolL(-1), respectively. These results indicate the great potential of the GO-BiNPs nanocomposite for improving the sensitivity of voltammetric procedures. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Reduced aggregation and cytotoxicity of amyloid peptides by graphene oxide/gold nanocomposites prepared by pulsed laser ablation in water.

    Science.gov (United States)

    Li, Jingying; Han, Qiusen; Wang, Xinhuan; Yu, Ning; Yang, Lin; Yang, Rong; Wang, Chen

    2014-11-12

    A novel and convenient method to synthesize the nanocomposites combining graphene oxides (GO) with gold nanoparticles (AuNPs) is reported and their applications to modulate amyloid peptide aggregation are demonstrated. The nanocomposites produced by pulsed laser ablation (PLA) in water show good biocompatibility and solubility. The reduced aggregation of amyloid peptides by the nanocomposites is confirmed by Thioflavin T fluorescence and atomic force microscopy. The cell viability experiments reveals that the presence of the nanocomposites can significantly reduce the cytotoxicity of the amyloid peptides. Furthermore, the depolymerization of peptide fibrils and inhibition of their cellular cytotoxicity by GO/AuNPs is also observed. These observations suggest that the nanocomposites combining GO and AuNPs have a great potential for designing new therapeutic agents and are promising for future treatment of amyloid-related diseases.

  13. Effect of mixing sequence on the curing of amine-hardened epoxy/ alumina nanocomposites as assessed by optical refractometry

    Directory of Open Access Journals (Sweden)

    2008-08-01

    Full Text Available High performance refractometry has been proven to be a useful tool to elucidate the isothermal curing process of nanocomposites. As a model system an amine-hardening epoxy filled with non-surface-treated alumina nanoparticles was selected. The tremendous resolution of this experimental technique is used to study morphological changes within nanocomposites via the refractive index. It is shown that these morphological changes are not simply due to the curing process but also depend on the sequence of mixing the nanoparticles either first into the resin or first into the hardener. Independent of the resin/hardener composition, the type of the mixing sequence discriminates systematically between two distinct refractive index curves produced by the curing process. The difference between the two refractive index curves increases monotonically with curing time, which underlines the importance of the initial molecular environment of the nanoparticles.

  14. Antimicrobial Bamboo Materials Functionalized with ZnO and Graphene Oxide Nanocomposites

    OpenAIRE

    Junyi Zhang; Bo Zhang; Xiufang Chen; Bingbing Mi; Penglian Wei; Benhua Fei; Xindong Mu

    2017-01-01

    Bamboo materials with improved antibacterial performance based on ZnO and graphene oxide (GO) were fabricated by vacuum impregnation and hydrothermal strategies. The Zn2+ ions and GO nanosheets were firstly infiltrated into the bamboo structure, followed by dehydration and crystallization upon hydrothermal treatment, leading to the formation of ZnO/GO nanocomposites anchored in the bulk bamboo. The bamboo composites were characterized by several techniques including scanning electron microsco...

  15. Cathodoluminescence and photoluminescence of swift ion irradiation modified zinc oxide-porous silicon nanocomposite

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Yogesh [CIICAp, UAEM, Av. Univ. 1001, Col. Chamilpa, Cuer., Mor., C.P. 62209 (Mexico); CIMAV, Av. Miguel de Cervantes 120, Compl. Indus. Chih., Chih., C.P. 31109 (Mexico); Herrera, Manuel [CNyN-UNAM, Ensenada Apdo. Postal 14, CP. 22800, Ensenada, B.C. (Mexico); Singh, Fouran [Inter University Accelarator Centre, Aruna Asaf Ali Marg, New Delhi-110067 (India); Olive-Mendez, S.F. [CIMAV, Av. Miguel de Cervantes 120, Compl. Indus. Chih., Chih., C.P. 31109 (Mexico); Kanjilal, D.; Kumar, Shiv [Inter University Accelarator Centre, Aruna Asaf Ali Marg, New Delhi-110067 (India); Agarwal, V., E-mail: vagarwal@uaem.mx [CIICAp, UAEM, Av. Univ. 1001, Col. Chamilpa, Cuer., Mor., C.P. 62209 (Mexico)

    2012-09-20

    We report the room temperature cathodoluminescence and photoluminescence of swift ion irradiated (130 MeV Nickel ion) porous silicon zinc oxide nanocomposites. The evolution of a broad and flat emission band from 1.5 to 3.5 eV is demonstrated. Annealing effect of irradiation is found to result in a relative increase in the band edge emission. Emission wavelength can be tuned in the complete visible range by changing the substrate characteristics.

  16. Green synthesis, characterization, and anticancer activity of hyaluronan/zinc oxide nanocomposites

    Directory of Open Access Journals (Sweden)

    Namvar F

    2016-07-01

    Full Text Available Farideh Namvar,1,2 Susan Azizi,3 Heshu Sulaiman Rahman,4–6 Rosfarizan Mohamad,1,3 Abdullah Rasedee,4 Mozhgan Soltani,2 Raha Abdul Rahim71Institute of Tropical Forestry and Forest Products (INTROP, Universiti Putra Malaysia, UPM Serdang, Selangor, Malaysia; 2Research Center for Animal Development Applied Biology, Mashhad Branch, Islamic Azad University, Mashhad, Iran; 3Department of Bioprocess Technology, Faculty of Biotechnology and Biomolecular Sciences, 4Department of Veterinary Laboratory Diagnosis, Faculty of Veterinary Medicine, Universiti Putra Malaysia, UPM Serdang, Selangor, Malaysia; 5Department of Clinic and Internal Medicine, College of Veterinary Medicine, University of Sulaimani, 6Department of Laboratory Medical Sciences, Komar University of Science and Technology, Sulaimani City, Kurdistan Region, Northern Iraq; 7Department of Cell and Molecular Biology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, UPM Serdang, Selangor, Malaysia Abstract: The study describes an in situ green biosynthesis of zinc oxide nanocomposite using the seaweed Sargassum muticum water extract and hyaluronan biopolymer. The morphology and optical properties of the hyaluronan/zinc oxide (HA/ZnO nanocomposite were determined by Fourier transform infrared spectroscopy, X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, and ultraviolet–vis analysis. Electron microscopy and X-ray diffraction analysis showed that the zinc oxide nanoparticles were polydispersed with a mean size of 10.2±1.5 nm. The nanoparticles were mostly hexagonal in crystalline form. The HA/ZnO nanocomposite showed the absorption properties in the ultraviolet zone that is ascribed to the band gap of zinc oxide nanocomposite. In the cytotoxicity study, cancer cells, pancreatic adenocarcinoma (PANC-1, ovarian adenocarcinoma (CaOV-3, colonic adenocarcinoma (COLO205, and acute promyelocytic leukemia (HL-60 cells

  17. Graphene oxide-silver nanocomposite as a promising biocidal agent against methicillin-resistant Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    de Moraes ACM

    2015-11-01

    Full Text Available Ana Carolina Mazarin de Moraes,1 Bruna Araujo Lima,2 Andreia Fonseca de Faria,1 Marcelo Brocchi,2 Oswaldo Luiz Alves1 1Laboratory of Solid State Chemistry, Institute of Chemistry, University of Campinas, Campinas, São Paulo, Brazil; 2Department of Genetics, Evolution and Bioagents, Institute of Biology, University of Campinas, Campinas, São Paulo, Brazil Background: Methicillin-resistant Staphylococcus aureus (MRSA has been responsible for serious hospital infections worldwide. Nanomaterials are an alternative to conventional antibiotic compounds, because bacteria are unlikely to develop microbial resistance against nanomaterials. In the past decade, graphene oxide (GO has emerged as a material that is often used to support and stabilize silver nanoparticles (AgNPs for the preparation of novel antibacterial nanocomposites. In this work, we report the synthesis of the graphene-oxide silver nanocomposite (GO-Ag and its antibacterial activity against relevant microorganisms in medicine. Materials and methods: GO-Ag nanocomposite was synthesized through the reduction of silver ions (Ag+ by sodium citrate in an aqueous GO dispersion, and was extensively characterized using ultraviolet-visible absorption spectroscopy, X-ray diffraction, thermogravimetric analysis, X-ray photoelectron spectroscopy, and transmission electron microscopy. The antibacterial activity was evaluated by microdilution assays and time-kill experiments. The morphology of bacterial cells treated with GO-Ag was investigated via transmission electron microscopy. Results: AgNPs were well distributed throughout GO sheets, with an average size of 9.4±2.8 nm. The GO-Ag nanocomposite exhibited an excellent antibacterial activity against methicillin-resistant S. aureus, Acinetobacter baumannii, Enterococcus faecalis, and Escherichia coli. All (100% MRSA cells were inactivated after 4 hours of exposure to GO-Ag sheets. In addition, no toxicity was found for either pristine GO or bare Ag

  18. Efficient One-Pot Synthesis of Colloidal Zirconium Oxide Nanoparticles for High-Refractive-Index Nanocomposites.

    Science.gov (United States)

    Liu, Chao; Hajagos, Tibor Jacob; Chen, Dustin; Chen, Yi; Kishpaugh, David; Pei, Qibing

    2016-02-01

    Zirconium oxide nanoparticles are promising candidates for optical engineering, photocatalysis, and high-κ dielectrics. However, reported synthetic methods for the colloidal zirconium oxide nanoparticles use unstable alkoxide precursors and have various other drawbacks, limiting their wide application. Here, we report a facile one-pot method for the synthesis of colloidally stable zirconium oxide nanoparticles. Using a simple solution of zirconium trifluoroacetate in oleylamine, highly stable zirconium oxide nanoparticles have been synthesized with high yield, following a proposed amidization-assisted sol-gel mechanism. The nanoparticles can be readily dispersed in nonpolar solvents, forming a long-term stable transparent solution, which can be further used to fabricate high-refractive-index nanocomposites in both monolith and thin-film forms. In addition, the same method has also been extended to the synthesis of titanium oxide nanoparticles, demonstrating its general applicability to all group IVB metal oxide nanoparticles.

  19. Surface Oxidation of Al2O3/SiC Nanocomposite: Phase Transformation and Microstructure

    Institute of Scientific and Technical Information of China (English)

    Cai Shu; Peng Zhenzhen; Feng Jie; Lu Feng

    2005-01-01

    The surface oxidation behavior of pressureless sintered Al2O3/SiC nanocomposite was studied from 1000 to 1400 ℃ for more than 10 h in air. Weight gain during the process of heat treatment was measured by TG analysis. Phase transformation and microstructure changes of these specimens due to oxidation were investigated with X-ray diffraction (XRD), SEM and EDX technology. Thermogravimetric analysis show that the weight gain as a result of oxidation of SiC become significant above 1200 ℃. In the range of 1000~1300 ℃, the SiC grits are usually coated with a layer of amorphous silica after oxidation. Above 1300 ℃, the amorphous silica reacted with alumina matrix and formed mullite or crystallized into cristobalite. The rate of oxidation depends on the formation of dense cristobalite film. Large amount of needle-like mullite and alumina crystals are formed on the surface after oxidation at 1400 ℃.

  20. Transparent luminescent hyperbranched epoxy/carbon oxide dot nanocomposites with outstanding toughness and ductility.

    Science.gov (United States)

    De, Bibekananda; Voit, Brigitte; Karak, Niranjan

    2013-10-23

    A luminescent transparent hyperbranched epoxy nanocomposite with previously unachieved outstanding toughness and elasticity has been created by incorporation of a very small amount of carbon oxide nanodots. The nanocomposites of the hyperbranched epoxy with carbon oxide dots at different dose levels (0.1, 0.5, and 1.0 wt %) have been prepared by an ex situ solution technique followed by curing with poly(amido-amine) at 100 °C. Different characterizations and evaluations of mechanical and optical properties of the nanocomposites have been performed. The toughness (area under the stress-strain curve) of the pristine system has been improved dramatically by 750% with only 0.5 wt % carbon oxide dots. The tensile strength has been enhanced from 38 to 46 MPa, whereas the elongation at break improved noticeably from 15 to 45%. Excellent adhesive strength combined with transparency and photoluminescent behavior renders these materials highly interesting as functional films in optical devices like light-emitting diodes and UV light detection systems as well as in anticounterfeiting applications.

  1. GRAPHENE BASED METAL AND METAL OXIDE NANOCOMPOSITES: SYNTHESIS, PROPERTIES AND THEIR APPLICATIONS

    KAUST Repository

    Khan, Mujeeb

    2015-06-11

    Graphene, an atomically thin two-dimensional carbonaceous material, has attracted tremendous attention in the scientific community, due to its exceptional electronic, electrical, and mechanical properties. Indeed, with the recent explosion of methods for a large-scale synthesis of graphene, the number of publications related to graphene and other graphene based materials have increased exponentially. Particularly the easy preparation of graphene like materials, such as, highly reduced graphene oxide (HRG) via reduction of graphite oxide (GO), offers a wide range of possibilities for the preparation of graphene based inorganic nanocomposites by the incorporation of various functional nanomaterials for a variety of applications. In this review, we discuss the current development of graphene based metal and metal oxide nanocomposites, with a detailed account of their synthesis and properties. Specifically, much attention has been given to their wide range of applications in various fields, including, electronics, electrochemical and electrical fields. Overall, by the inclusion of various references, this review covers in detail aspects of the graphene-based inorganic nanocomposites.

  2. Photocatalytic synthesis of TiO(2) and reduced graphene oxide nanocomposite for lithium ion battery.

    Science.gov (United States)

    Qiu, Jingxia; Zhang, Peng; Ling, Min; Li, Sheng; Liu, Porun; Zhao, Huijun; Zhang, Shanqing

    2012-07-25

    In this work, we synthesized graphene oxide (GO) using the improved Hummers' oxidation method. TiO2 nanoparticles can be anchored on the GO sheets via the abundant oxygen-containing functional groups such as epoxy, hydroxyl, carbonyl, and carboxyl groups on the GO sheets. Using the TiO2 photocatalyst, the GO was photocatalytically reduced under UV illumination, leading to the production of TiO2-reduced graphene oxide (TiO2-RGO) nanocomposite. The as-prepared TiO2, TiO2-GO, and TiO2-RGO nanocomposite were used to fabricate lithium ion batteries (LIBs) as the active anode materials and their corresponding lithium ion insertion/extraction performance was evaluated. The resultant LIBs of the TiO2-RGO nanocomposite possesses more stable cyclic performance, larger reversible capacity, and better rate capability, compared with that of the pure TiO2 and TiO2-GO samples. The electrochemical and materials characterization suggest that the graphene network provides efficient pathways for electron transfer, and the TiO2 nanoparticles prevent the restacking of the graphene nanosheets, resulting in the improvement in both electric conductivity and specific capacity, respectively. This work suggests that the TiO2 based photocatalytic method could be a simple, low-cost, and efficient approach for large-scale production of anode materials for lithium ion batteries.

  3. Synthesis, Characterization, and Microwave Absorption Properties of Reduced Graphene Oxide/Strontium Ferrite/Polyaniline Nanocomposites.

    Science.gov (United States)

    Luo, Juhua; Shen, Pan; Yao, Wei; Jiang, Cuifeng; Xu, Jianguang

    2016-12-01

    Strontium ferrite nanoparticles were prepared by a coprecipitation method, and reduced graphene oxide/strontium ferrite/polyaniline (R-GO/SF/PANI) ternary nanocomposites were prepared by in situ polymerization method. The morphology, structure, and magnetic properties of the ternary nanocomposites were investigated by X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), TEM, Raman, and VSM. The microwave-absorbing properties of the composites were measured by a vector network analyzer. The XRD patterns show the single phase of strontium hexaferrite without other intermediate phases. TEM photographs reveal that strontium ferrite nanoparticles are uniformly dispersed on the surfaces of R-GO sheets. The R-GO/SF/PANI nanocomposite exhibited the best absorption property with the optimum matching thickness of 1.5 mm in the frequency of 2-18 GHz. The value of the maximum RL was -45.00 dB at 16.08 GHz with the 5.48-GHz bandwidth. The excellent absorption properties of R-GO/SF/PANI nanocomposites indicated their great potential as microwave-absorbing materials.

  4. Thermal, Mechanical, and Electrical Properties of Graphene Nanoplatelet/Graphene Oxide/ Polyurethane Hybrid Nanocomposite.

    Science.gov (United States)

    Pokharel, Pashupati; Lee, Sang Hyub; Lee, Dai Soo

    2015-01-01

    Hybrid nanocomposites of polyurethane (PU) were prepared by in-situ polymerization of 4,4'- diphenyl methane diisocyanate (MDI) with mixture of graphene oxide (GO) and graphene nanoplatelet (GNP) dispersed in a poly(tetramethylene ether glycol) (PTMEG). Effects of the fillers, GO and GNP, on the thermal, mechanical, and electrical properties of the nanocomposites of PU were investigated. Sonication of the hybrid of GNP and GO with PTMEG enabled effective dispersion of the fillers in the solution than the sonication of GNP alone. The addition of PTMEG in the solution prevented the GNPs from the restacking during the drying process. It was observed that the electrical conductivity and mechanical property of the nanocomposites based on the hybrid of GO and GNP were superior to the nanocomposite based on GNP alone at the same loading of the filler. At the loading of the 3 wt% hybrid filler in PU, we observed the improvement of Young's modulus -200% and the surface resistivity of 10(9.5) ohm/sq without sacrificing the elongation at break.

  5. Preparation, characterization and dye adsorption of Au nanoparticles/ZnAl layered double oxides nanocomposites

    Science.gov (United States)

    Zhang, Yu Xin; Hao, Xiao Dong; Kuang, Min; Zhao, Han; Wen, Zhong Quan

    2013-10-01

    In this work, Au/ZnAl-layer double oxides (LDO) nanocomposties were prepared through a facile calcination process of AuCl4- intercalated ZnAl-layered double hydroxides (LDHs) nanocomposites. The morphology and crystal structure of these nanocomposites were characterized by Scanning electron microscopy (SEM), transmission electron microscopy (TEM), powder X-ray diffraction (XRD), and N2 sorption analysis. By tailoring the process parameter, such as calcination temperature, heating time and the component composition, the adsorption properties of methyl orange (MO) on the Au/ZnAl-LDO nanocomposites were investigated in this work. In a typical adsorption process, it was found that 0.985 mg of MO (0.01 g L-1, 100 mL, 1 mg of MO in total) can be removed in 60 min by utilizing only 2.5 mg of Au/ZnAl-LDO (Au content, 1%) as adsorbents. Our adsorption data obtained from the Langmuir model also gave good values of the determination coefficient, and the saturated adsorption capacity of Au/ZnAl-LDO nanocomposites for MO was found to be 627.51 mg/g under ambient condition (e.g., room temperature, 1 atm). In principle, these hybrid nanostructures with higher adsorption abilities could be very promising adsorbents for wastewater treatment.

  6. Synthesis of Silver-Doped Zinc Oxide Nanocomposite by Pulse Mode Ultrasonication and Its Characterization Studies

    Directory of Open Access Journals (Sweden)

    T. Siva Vijayakumar

    2013-01-01

    Full Text Available The synthesis of silver-doped zinc oxide (Ag:ZnO nanocomposite material was achieved using a simple chemical coprecipitation method, in which 0.2 M zinc chloride and 0.001 M silver nitrate coprecipitated with 25% ammonia solution by pulse mode dispersion using ultrasonicator. The obtained silvery white precipitate was dried overnight at 110°C in hot air oven, and the powder was collected. The resulted Ag:ZnO nanocomposite was structurally and optically characterized using various techniques. The X-ray diffraction (XRD pattern clearly showed the presence of crystalline Ag:ZnO particles. Further, UV-Vis spectrophotometer and fourier transform infrared spectroscopy (FT-IR results showed the presence of Ag:ZnO nanocomposite at specific wavelengths. The scanning electron microscopy (SEM and transmission electron microscopy (TEM analysis confirm that the synthesized Ag:ZnO nanocomposite material was truncated nanorod in shape and has 48 to 226 nm size in diameter.

  7. Enhanced Stability and Reusability of Alcohol Dehydrogenase Covalently Immobilized on Magnetic Graphene Oxide Nanocomposites.

    Science.gov (United States)

    Liu, Liangliang; Yu, Jingang; Chen, Xiaoqing

    2015-02-01

    Graphene oxide (GO) has a unique planar structure and contains many functional groups. As a functional material, it can be functionalized with biomolecules and nanomaterials for various applications. In this study, Magnetic GO (MGO) nanocomposites were synthesized according to covalent binding of amino Fe3O4 nanoparticles onto the GO surface and the as-made nanocomposites were successfully applied as supports for the immobilization of alcohol dehydrogenase (ADH). Compared with free ADH and Fe3O4 nanoparticles immobilized ADH (MNP-ADH), the MGO immobilized ADH (MGO-ADH) exhibited a wider pH stability range and a better thermal stability. Furthermore, the MGO-ADH exhibited better storage stability and reusability than MNP-ADH after recovered by magnetic separations. The MGO-ADH maintained 35.1% activity after 20 days storage and lost about 20.4% activity after ten times usage. The Michaelis constant (Km) of MGO-ADH was close to that of free ADH. The results showed the MGO nanocomposites were appropriate for the immobilization of enzyme. As a novel support, MGO nanocomposites effectively increased the stability of enzyme, allowed the reuse or continuous use of enzymes and therefore improved the potential use in practical.

  8. An organic indicator functionalized graphene oxide nanocomposite-based colorimetric assay for the detection of sarcosine.

    Science.gov (United States)

    Xue, Zhonghua; Yin, Bo; Wang, Hui; Li, Mengqian; Rao, Honghong; Liu, Xiuhui; Zhou, Xinbin; Lu, Xiaoquan

    2016-03-14

    Rapid detection of sarcosine is a key requirement for both diagnosis and treatment of disease. We report here a simple yet sensitive colorimetric nanocomposite platform for rapid detection of sarcosine in alkaline media. The approach exploited the benefits of a rapid color-producing reaction between an organic indicator, 1,2-naphthoquinone-4-sulphonic acid sodium salt (NQS), and the analyte of sarcosine species as well as the good catalytic ability of graphene oxide (GO) to the formation of highly colored products due to its good water dispersibility, extremely large surface area and facile surface modification. As a result, a NQS functionalized GO nanocomposite through π-π stacking has been demonstrated to be useful as a highly efficient catalyst system for the selective and sensitive colorimetric determination of sarcosine by providing a nanocomposite-amplified colorimetric response. Meanwhile, the strategy offered excellent selectivity toward sarcosine species against other amino acids as well as a satisfying detection limit of 0.73 μM. More importantly, by using an electrochemical method, a credible sensing mechanism of GO nanocomposite-based colorimetric platform for a special analyte determination can be easily verified and elucidated, which also provides an attractive alternative to conventional characterization strategies.

  9. Manganese hexacyanoferrate derived Mn3O4 nanocubes-reduced graphene oxide nanocomposites and their charge storage characteristics in supercapacitors.

    Science.gov (United States)

    Subramani, K; Jeyakumar, D; Sathish, M

    2014-03-14

    Mn3O4-reduced graphene oxide (RGO) nanocomposites were prepared by chemical decomposition of the manganese hexacyanoferrate (MnHCF) complex directly on the graphene surface. XRD studies revealed the formation of crystalline hausmannite Mn3O4 nanocubes in the as-prepared nanocomposites without any heat treatment. The FE-SEM images showed the formation of Mn3O4 nanocubes on the graphene surface in the as-prepared nanocomposites. HR-TEM studies confirmed the homogeneous dispersion of ∼25 nm Mn3O4 nanocubes on graphene nanosheets. The amount of Mn3O4 nanocubes and graphene in the nanocomposites was estimated using TGA analysis from room temperature to 800 °C in air. The FT-IR and Raman spectroscopic analysis confirmed the functional groups in the nanocomposites and defects in graphene nanosheets in the nanocomposites. Cyclic voltammetry and galvanostatic charge-discharge experiments demonstrated a high specific capacitance of 131 F g(-1) in 1 M Na2SO4 electrolyte at a current density of 0.5 A g(-1) for the RGM-0.5 nanocomposite. A capacitance retention of 99% was observed for 500 charge-discharge cycles at a current density of 5 A g(-1), which conformed the excellent stability of the RGM electrodes. The prepared Mn3O4-RGO nanocomposites are promising for electrochemical energy storage.

  10. Electrical conductivity of activated carbon-metal oxide nanocomposites under compression: a comparison study.

    Science.gov (United States)

    Barroso-Bogeat, A; Alexandre-Franco, M; Fernández-González, C; Macías-García, A; Gómez-Serrano, V

    2014-12-01

    From a granular commercial activated carbon (AC) and six metal oxide (Al2O3, Fe2O3, SnO2, TiO2, WO3 and ZnO) precursors, two series of AC-metal oxide nanocomposites were prepared by wet impregnation, oven-drying at 120 °C, and subsequent heat treatment at 200 or 850 °C in an inert atmosphere. Here, the electrical conductivity of the resulting products was studied under moderate compression. The influence of the applied pressure, sample volume, mechanical work, and density of the hybrid materials was thoroughly investigated. The DC electrical conductivity of the compressed samples was measured at room temperature by the four-probe method. Compaction assays suggest that the mechanical properties of the nanocomposites are largely determined by the carbon matrix. Both the decrease in volume and the increase in density were relatively small and only significant at pressures lower than 100 kPa for AC and most nanocomposites. In contrast, the bulk electrical conductivity of the hybrid materials was strongly influenced by the intrinsic conductivity, mean crystallite size, content and chemical nature of the supported phases, which ultimately depend on the metal oxide precursor and heat treatment temperature. The supported nanoparticles may be considered to act as electrical switches either hindering or favouring the effective electron transport between the AC cores of neighbouring composite particles in contact under compression. Conductivity values as a rule were lower for the nanocomposites than for the raw AC, all of them falling in the range of semiconductor materials. With the increase in heat treatment temperature, the trend is toward the improvement of conductivity due to the increase in the crystallite size and, in some cases, to the formation of metals in the elemental state and even metal carbides. The patterns of variation of the electrical conductivity with pressure and mechanical work were slightly similar, thus suggesting the predominance of the pressure

  11. Swift heavy ion induced modification in morphological and physico-chemical properties of tin oxide nanocomposites

    Science.gov (United States)

    Jaiswal, Manoj Kumar; Kanjilal, D.; Kumar, Rajesh

    2013-11-01

    Nanocomposite thin films of tin oxide (SnO2)/titanium oxide (TiO2) were grown on silicon (1 0 0) substrates by electron beam evaporation deposition technique using sintered nanocomposite pellet of SnO2/TiO2 in the percentage ratio of 95:5. Sintering of the nanocomposite pellet was done at 1300 °C for 24 h. The thicknesses of these films were measured to be 100 nm during deposition using piezo-sensor attached to the deposition chamber. TiO2 doped SnO2 nanocomposite films were irradiated by 100 MeV Au8+ ion beam at fluence range varying from 1 × 1011 ions/cm2 to 5 × 1013 ions/cm2 at Inter University Accelerator Center (IUAC), New Delhi, India. Chemical properties of pristine and ion irradiation modified thin films were characterized by Fourier Transform Infrared (FTIR) spectroscopy. FTIR peak at 610 cm-1 confirms the presence of O-Sn-O bridge of tin (IV) oxide signifying the composite nature of pristine and irradiated thin films. Atomic Force Microscope (AFM) in tapping mode was used to study the surface morphology and grain growth due to swift heavy ion irradiation at different fluencies. Grain size calculations obtained from sectional analysis of AFM images were compared with results obtained from Glancing Angle X-ray Diffraction (GAXRD) measurements using Scherrer’s formulae. Phase transformation due to irradiation was observed from Glancing Angle X-ray Diffraction (GAXRD) results. The prominent 2θ peaks observed in GAXRD spectrum are at 30.67°, 32.08°, 43.91°, 44.91° and 52.35° in the irradiated films.

  12. Digital laser printing of metal/metal-oxide nano-composites with tunable electrical properties

    Science.gov (United States)

    Zenou, M.; Sa'ar, A.; Kotler, Z.

    2016-01-01

    We study the electrical properties of aluminum structures printed by the laser forward transfer of molten, femtoliter droplets in air. The resulting printed material is an aluminum/aluminum-oxide nano-composite. By controlling the printing conditions, and thereby the droplet volume, its jetting velocity and duration, it is possible to tune the electrical resistivity to a large extent. The material resistivity depends on the degree of oxidation which takes place during jetting and on the formation of electrical contact points as molten droplets impact the substrate. Evidence for these processes is provided by FIB cross sections of printed structures.

  13. Graphene Oxide as Reinforcement in Epoxy Based Nanocomposites.

    OpenAIRE

    Svendsen, Elizabeth Martine

    2014-01-01

    Graphene oxide has received much attention in recent years because of its many promising properties. Graphene oxide can be used to produce graphene in large quantities, and in addition graphene oxide has many promising properties itself, such as its high level of dispersion in polar solvents, and good compatibility with various polymers. Addition of nanoparticles in composite materials have been tested for many years, and in recent years carbon nanotubes have been in focus as a reinforcement....

  14. Titanium–vanadium oxide nanocomposite thin films: Synthesis, characterization and antibacterial activity

    Energy Technology Data Exchange (ETDEWEB)

    Wren, A.W.; Adams, B.M.; Pradhan, D.; Towler, M.R.; Mellott, N.P., E-mail: mellott@alfred.edu

    2014-04-01

    A sol–gel based deposition method was successfully developed to produce a series of crack-free, spatially homogeneous undoped/silver doped titania–vanadia oxide nanocomposite thin films. Thin films were characterized using Glancing Incidence X-ray Diffraction (GIXRD), X-ray Photoelectron Spectroscopy (XPS), and Ultraviolet Visible Spectroscopy (UV–Vis). It was determined via both XRD and XPS that when calcined at 450 °C the nanocomposite crystallinity was a function of sol composition. Additionally, it was determined via GIXRD that upon silver doping, silver was incorporated into the vanadia structure or present in silver oxide form in crystalline films. A red shift within the UV–Vis spectra was observed with an increase of vanadia concentration from 0 to 100% respectively. Antibacterial analysis conducted on Escherichia coli and Staphylococcus epidermidis demonstrated that films exposed to light showed greater antibacterial properties. - Highlights: • Nanocomposite crystallinity was a function of sol composition. • Silver was incorporated into the vanadia structure. • A red shift was observed with an increase of vanadia concentration. • Antibacterial analysis conducted on Escherichia coli and Staphylococcus epidermidis.

  15. Thermal and mechanical properties of reduced graphene oxide/polyurethane nanocomposite.

    Science.gov (United States)

    Pokharel, Pashupati; Lee, Dai Soo

    2014-08-01

    Reduced graphene oxide (RGO) based polyurethane (PU) nanocomposites have been successfully prepared without using solvent by in-situ polymerization. RGO was derived from microwave (MW) irradiation of graphite oxide (GO) powder prepared by a modified Hummer's method. A minimum amount of poly(tetramethylene glycol) (PTMEG) was added during the dispersion of RGO in a solvent to stabilize the graphene sheets and to prevent RGO from the restacking after the removal of the solvent. After the reaction of RGO with 4,4'-diphenylmethane diisocyanate (MDI), we obtained the concentrate of RGO in MDI with a minimum amount of PTMEG. Our method facilitated the fine dispersion of RGO in PU elastomers and improved the interfacial strength between RGO and PU. With the incorporation of 2.0 wt% of RGO, the tensile strength and Young's modulus of the PU nanocomposites increased by 30% and 50%, respectively without sacrificing the elongation at break. It was found that the crystalline portion of hard segments of the PU was lowered by the RGO in the nanocomposites.

  16. Li2S-reduced graphene oxide nanocomposites as cathode material for lithium sulfur batteries

    Science.gov (United States)

    Han, Kai; Shen, Jingmei; Hayner, Cary M.; Ye, Hongqi; Kung, Mayfair C.; Kung, Harold H.

    2014-04-01

    A lithium sulfide-reduced graphene oxide nanocomposite (Li2S-rGO) was synthesized and evaluated as the cathode material and Li source for the assembly of Li-S batteries. The composite, with a unique 3-D pocket structure, was synthesized by a combination of facile solution chemistry and thermal treatment. The as-prepared Li2S-rGO nanocomposites were characterized by X-ray photoelectron spectroscopy, X-ray diffraction and scanning electron microscopy, which showed 20-40 nm Li2S particles homogeneously dispersed between reduced graphene oxide sheets. Li2S contents as high as ∼66% could be obtained. When used with an electrolyte containing LiNO3 and polysulfide, the Li2S-rGO nanocomposites exhibited a high initial capacity of 982 mAh g-1 Li2S. However, there was noticeable capacity fade in subsequent cycles, probably due to polysulfide dissolution and the shuttle mechanism, but a capacity of 315 mAh g-1 could still be obtained after 100 cycles, with 90-95% coulomb efficiency. The effect of polysulfide additive in the electrolyte on the activation of Li2S in the first delithiation step was discussed.

  17. Ionic liquid-modified metal sulfides/graphene oxide nanocomposites for photoelectric conversion

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yu; Zhang, Yù; Pei, Qi; Feng, Ting; Mao, Hui; Zhang, Wei; Wu, Shuyao; Liu, Daliang; Wang, Hongyu; Song, Xi-Ming, E-mail: songlab@lnu.edu.cn

    2015-08-15

    Graphical abstract: - Highlights: • Metal sulfide (CdS, ZnS, Ag{sub 2}S)/GO nanocomposites were prepared by electrostatic adherence. • Ionic liquid was used to link the metal sulfide and GO in the electrostatic adherence process. • The as-prepared samples showed enhanced photocurrent and highly efficient photocatalytic activity under visible light irradiation. - Abstract: Ionic liquid-modified metal sulfides/graphene oxide nanocomposites are prepared via a facile electrostatic adsorption. Ionic liquid (IL) is firstly used as surface modifier and structure-directing agent of metal sulfide (MS) crystallization process, obtaining ionic liquid modified-MS (IL-MS) nanoparticles with positive charges on surface. IL-MS/GO is obtained by electrostatic adherence between positively charged IL-MS and negatively charged graphene oxide (GO). The as-prepared sample shows enhanced photocurrent and highly efficient photocatalytic activity under visible light irradiation, indicating IL-MS/GO nanocomposites greatly promoted the separation of photogenerated electron–hole pairs.

  18. Enhancement of the thermo-mechanical properties and efficacy of mixing technique in the preparation of graphene/PVC nanocomposites compared to carbon nanotubes/PVC

    Institute of Scientific and Technical Information of China (English)

    Mudassir Hasan; Moonyong Lee

    2014-01-01

    Thin films of poly vinyl chloride (PVC)/multiwalled carbon nanotubes (MWCNT) and PVC/graphene (GN) nanocomposites were prepared by mixing in the presence of different quantities of nanoparticles. Film casting was performed using tetrahydrofuran as a solvent. The as-prepared PVC/MWCNT and PVC/GN nanocomposites were characterized by scanning electron microscopy, Raman spectroscopy, X-ray diffraction, thermogravimetric analysis, differential scanning calorimetry, dynamic mechanical analysis, and diffused reflectance spectroscopy. Only the PVC/GN nanocomposite films were evaluated further for detailed mechanical analysis because of the poor dispersion of MWCNTs in PVC. The PVC/GN nanocomposite films were thermo-mechanically more stable than the PVC films. These nanocomposites have potential as a replacement material for PVC and PVC/MWCNT owing to their better dispersion and high stability.

  19. Enhancement of the thermo-mechanical properties and efficacy of mixing technique in the preparation of graphene/PVC nanocomposites compared to carbon nanotubes/PVC

    Directory of Open Access Journals (Sweden)

    Mudassir Hasan

    2014-12-01

    Full Text Available Thin films of poly vinyl chloride (PVC/multiwalled carbon nanotubes (MWCNT and PVC/graphene (GN nanocomposites were prepared by mixing in the presence of different quantities of nanoparticles. Film casting was performed using tetrahydrofuran as a solvent. The as-prepared PVC/MWCNT and PVC/GN nanocomposites were characterized by scanning electron microscopy, Raman spectroscopy, X-ray diffraction, thermogravimetric analysis, differential scanning calorimetry, dynamic mechanical analysis, and diffused reflectance spectroscopy. Only the PVC/GN nanocomposite films were evaluated further for detailed mechanical analysis because of the poor dispersion of MWCNTs in PVC. The PVC/GN nanocomposite films were thermo-mechanically more stable than the PVC films. These nanocomposites have potential as a replacement material for PVC and PVC/MWCNT owing to their better dispersion and high stability.

  20. Chitosan-iron oxide nanocomposite based electrochemical aptasensor for determination of malathion.

    Science.gov (United States)

    Prabhakar, Nirmal; Thakur, Himkusha; Bharti, Anu; Kaur, Navpreet

    2016-10-05

    An electrochemical aptasensor based on chitosan-iron oxide nanocomposite (CHIT-IO) film deposited on fluorine tin Oxide (FTO) was developed for the detection of malathion. Iron oxide nanoparticles were prepared by co-precipitation method and characterized by Transmission electron microscopy and UV-Visible spectroscopy. The biotinylated DNA aptamer sequence specific to the malathion was immobilized onto the iron oxide doped-chitosan/FTO electrode by using streptavidin as linking molecule. Various characterization studies like Field Emission-Scanning Electron Microscopy (FE-SEM), Fourier Transform Infrared Spectroscopy (FT-IR), and Electrochemical studies were performed to attest the successful fabrication of bioelectrodes. Experimental parameters like aptamer concentration, response time, stability of electrode and reusability studies were optimized. Aptamer immobilized chitosan-iron oxide nanocomposite (APT/SA/CHIT-IO/FTO) bioelectrodes exhibited LOD of about 0.001 ng/mL within 15 min and spike-in studies revealed about 80-92% recovery of malathion from the lettuce leaves and soil sample. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Manufacturing and characterisation of PMMA-graphene oxide (GO nanocomposite sandwich films with electrospun nano-fibre core

    Directory of Open Access Journals (Sweden)

    D. Bhattacharyya

    2012-12-01

    Full Text Available Purpose: Nanocomposite materials, comprising of polymer matrices and nano-sized reinforcements, exhibit significantly enhanced mechanical and functional properties at extremely low filler loading. In recent years, graphene oxide (GO has emerged as a new class of low cost nano-filler with high mechanical strength and stiffness, and alterable electrical properties. For nano-fillers with layered structure like GO, complete exfoliation and uniform dispersion of filler in the polymer matrices is essential to enhance the matrix-filler interaction and in turn the mechanical and/or functional property improvement. Conventional nanocomposite manufacturing methods including in-situ polymerisation and solvent processing encounter the problem of agglomeration of GO films. Additionally, its low bulk density presents difficulties in handling, and the energy requirement for mechanical mixing and extrusion processes is very high. In this work, we report manufacturing of poly(methyl methacrylate–graphene oxide (PMMA-GO nano-fibre mat using relatively novel approach of employing electrospinning technique. The manufactured electrospun core was inserted between plain polymer layers to prepare a robust and easy to handle sandwich film. Morphology and structure of the PMMA-GO nano-fibre cores was evaluated with scanning and transmission electron microscopy and X-ray diffractometry. The manufactured nano-fibre mat samples exhibited uniform diameter and dispersion. The functional parameters including thermal stability and gas barrier were evaluated with differential scanning calorimetry and oxygen permeation testing, and these functional properties were observed to be superior to that of monolithic polymer counterparts.

  2. Optical Band Gap and Thermal Diffusivity of Polypyrrole-Nanoparticles Decorated Reduced Graphene Oxide Nanocomposite Layer

    Directory of Open Access Journals (Sweden)

    Amir Reza Sadrolhosseini

    2016-01-01

    Full Text Available A polypyrrole-nanoparticles reduced graphene oxide nanocomposite layer was prepared using electrochemical method. The prepared samples were characterized using Fourier transform infrared spectroscopy, field emission scanning electron microscopy, and UV-visible spectroscopy. The band gap of nanocomposite layers was calculated from UV-visible spectra and the thermal diffusivity of layers was measured using a photoacoustic technique. As experimental results, the optical band gap was in the range between 3.580 eV and 3.853 eV, and thermal diffusivity was increased with increasing the layer thickness from 2.873 cm2/s to 12.446 cm2/s.

  3. Label-free amino acid detection based on nanocomposites of graphene oxide hybridized with gold nanoparticles.

    Science.gov (United States)

    Zhang, Qian; Zhang, Diming; Lu, Yanli; Xu, Gang; Yao, Yao; Li, Shuang; Liu, Qingjun

    2016-03-15

    Nanocomposites of graphene oxide and gold nanoparticles (GO/GNPs) were synthesized for label-free detections of amino acids. Interactions between the composites and amino acids were investigated by both naked-eye observation and optical absorption spectroscopy. The GO/GNPs composites displayed apparent color changes and absorption spectra changes in presences of amino acids including glutamate, aspartate, and cysteine. The interaction mechanisms of the composites and amino acids were discussed and explored with sulfhydryl groups and non-α-carboxylic groups on the amino acids. Sensing properties of the composites were tested, while pure gold particles were used as the control. The results suggested that the GO/GNPs composites had better linearity and stability in dose-dependent responses to the amino acids than those of the particles, especially in detections for acidic amino acids. Therefore, the nanocomposites platform can provide a convenient and efficient approach for label-free optical detections of important molecules such as amino acids.

  4. Phytic acid/graphene oxide nanocomposites modified electrode for electrochemical sensing of dopamine.

    Science.gov (United States)

    Wang, Donglei; Xu, Fei; Hu, Jiajie; Lin, Meng

    2017-02-01

    An electrochemical sensor for determining dopamine was developed by modifying phytic acid/graphene oxide (PA/GO) nanocomposites onto a glassy carbon electrode (GCE). PA functionalized GO was prepared by an ultra-sonication method. Subsequently, the PA/GO nanocomposites were drop-casted on a glassy carbon substrate. The structural feature of the PA/GO modified GCE was confirmed by attenuated total reflection infrared (ATR-IR) spectroscopy. The proposed electrochemical sensor was applied to detect various concentrations of DA by differential pulse voltammetry (DPV). The PA/GO/GCE was considered to be highly sensitive to DA in the range of 0.05-10μM. In addition, the PA/GO/GCE demonstrated high electrochemical selectivity toward DA in the presence of ascorbic acid (AA) and uric acid (UA). The prepared electrochemical DA sensor was applied for detection of DA in dopamine hydrochloride injection and spiked samples of human urine with satisfactory results.

  5. New strain states and radical property tuning of metal oxides using a nanocomposite thin film approach

    Directory of Open Access Journals (Sweden)

    Judith MacManus-Driscoll

    2015-06-01

    Full Text Available Auxetic-like strain states were generated in self-assembled nanocomposite thin films of (Ba0.6Sr0.4TiO31−x − (Sm2O3x(BSTO − SmO. A switch from auxetic-like to elastic-like strain behavior was observed for x > 0.50, when the SmO switched from being nanopillars in the BSTO matrix to being the matrix with BSTO nanopillars embedded in it. A simple model was adopted to explain how in-plane strain varies with x. At high x (0.75, strongly enhanced ferroelectric properties were obtained compared to pure BSTO films. The nanocomposite method represents a powerful new way to tune the properties of a wide range of strongly correlated metal oxides whose properties are very sensitive to strain.

  6. Comparision between different metal oxide nanostructures and nanocomposites for sensing, energy generation, and energy harvesting

    Science.gov (United States)

    Willander, Magnus; Alnoor, Hatim; Elhag, Sami; Ibupoto, Zafar Hussain; Nour, Eiman Satti; Nur, Omer

    2016-02-01

    Highlights from research on different nanocomposites and nanostructures for sensing and other energy related applications will be presented. The synthesized nanostructures and nanocomposites presented here were all obtained using the low temperature (textile and paper. We here present results from different metal oxide nanostructures employed for chemical sensing and some innovative energy related applications. Efficient sensitive and selective sensing of dopamine, melamine, and glucose are presented as some examples of self-powered sensors utilizing the electrochemical phenomenon i.e. transferring chemical energy into electrical signal. Further the use of nanomaterials for developing selfpowered devices utilizing mechanical ambient energy is presented via piezoelectric and triboelectric effects. Here the self-powered devices and systems were relying on utilizing the electormechanical phenomenon i.e. transferring ambient mechanical energy into useful electrical energy. Finally the visibility of nanomaterials prepared by the low temperature chemical synthesis as possible low cost replacement of Pt electrodes for hydrogen production is briefly presented and discussed.

  7. Photodegradation of odorous 2-mercaptobenzoxazole through zinc oxide/hydroxyapatite nanocomposite

    DEFF Research Database (Denmark)

    Buazar, Foad; Alipouryan, S.; Kroushawi, Feisal

    2015-01-01

    In this study, ZnO/HAP nanocomposite with excellent photocatalytic activities was successfully synthesized by sol–gel method and used for degradation of 2-mercaptobenzoxazole (MBO) as model of odorous mercaptan compound in water. To optimize the performance of ZnO/HAP photocatalytic capabilities......, ZnO/HAP loading (0.05–0.3 g/L), irradiation time (15–180 min), pH (3–11) and initial concentration of MBO (10–100 ppm) were investigated. At neutral pH of 7, the highest amount of the MBO (99.45 %) was degraded by ZnO/HAP nanocomposite through photocatalytic oxidation process within 2 h...

  8. Surface characterization of Laponite-Poly(ethylene oxide) nanocomposite films

    Science.gov (United States)

    Stefanescu, Eduard A.; Negulescu, Ioan I.; Daly, William H.; Donose, Bogdan C.; Nguyen, Anh V.

    2008-03-01

    The aim of the present work is to understand how ionic strength of precursor polymer-clay gels influences the final structure of multilayered nanocomposite films fabricated from such gels. We have prepared three aqueous precursor gels containing 3wt% LRD, 2wt% PEO and 95wt% water, in which the salt concentrations were kept at 0X, 1X and 3X with X = 5.57 * 10^- 5 g NaCl/mL. The Laponite (LRD) - PEO multilayered films (LRD60%-PEO40%) were fabricated by manually spreading and drying each gel on a glass slide. Prior to the AFM measurements the polymer-clay composite films where freeze-dried by immersion in liquid nitrogen until they were totally degassed. Frozen samples where then fractured and left for additional drying for 24 hours in a desiccator. The imaging procedure employed here was tapping-mode AFM. Distinct features were identified on the layered transversal surface of the films, and were attributed to the different salt concentrations in the samples. Addition of salt increases the adhesion and compactness properties of the nanoparticles, as a more uniform side surface can be observed after freeze-fracturing the materials.

  9. Nanoclay embedded mixed matrix PVDF nanocomposite membrane: Preparation, characterization and biofouling resistance

    Energy Technology Data Exchange (ETDEWEB)

    Rajabi, Hamid [Membrane Research Centre, Department of Chemical Engineering, Razi University, Tagh Bostan, 67149 Kermanshah (Iran, Islamic Republic of); Department of Civil Engineering, Razi University, 67149 Kermanshah (Iran, Islamic Republic of); Ghaemi, Negin, E-mail: negin_ghaemi@kut.ac.ir [Department of Chemical Engineering, Kermanshah University of Technology, 67178 Kermanshah (Iran, Islamic Republic of); Madaeni, Sayed S. [Membrane Research Centre, Department of Chemical Engineering, Razi University, Tagh Bostan, 67149 Kermanshah (Iran, Islamic Republic of); Daraei, Parisa [Department of Chemical Engineering, Kermanshah University of Technology, 67178 Kermanshah (Iran, Islamic Republic of); Khadivi, Mohammad Ali [Friedrich-Alexander University, Erlangen-Nuremberg, Egerland Strasse 3, D-91058 Erlangen (Germany); Falsafi, Monir [Department of Chemistry, Faculty of Science, Razi University, 67149 Kermanshah (Iran, Islamic Republic of)

    2014-09-15

    Highlights: • Nanocomposite membranes were prepared by addition of OMMT to PVDF membrane. • Addition of nanoclay considerably increased the hydrophilicity of PVDF membrane. • Nanocomposite membranes had higher water flux and antifouling properties. • Fouling of membranes blended with nanoclay (<4 wt.%) reduced. - Abstract: In this paper, nanocomposite PVDF/nanoclay membranes were prepared with addition of different concentrations of organically modified montmorillonite (OMMT) into the polymeric casting solution using combination of solution dispersion and phase inversion methods. Membranes were characterized by use of X-ray diffraction (XRD), water contact angle, scanning electron microscopy (SEM) and atomic force microscopy (AFM), and their performances were evaluated in terms of pure water flux and fouling parameters. The surface hydrophilicity of all nanocomposites markedly improved compared to nascent PVDF. In addition, XRD patterns revealed the formation of intercalated layers of mineral clays in PVDF matrix. SEM and AFM images showed that addition of OMMT resulted in nanocomposite membranes with thinner skin layer and higher porosity rather than PVDF membranes. Pure water flux of PVDF/OMMT membranes increased significantly (particularly for fabricated membranes by 4 and 6 wt.% OMMT) compared to that of PVDF membrane. Moreover, nanocomposite membranes showed the elevated antifouling properties, and flux recovery of nascent PVDF membranes increased from 51 to 72% with addition of 2 wt.% OMMT nanoparticles. These nanocomposite membranes also offered a remarkable reusability and durability against biofouling.

  10. Graphite oxide-intercalated anionic clay and its decomposition to graphene-inorganic material nanocomposites.

    Science.gov (United States)

    Nethravathi, C; Rajamathi, Jacqueline T; Ravishankar, N; Shivakumara, C; Rajamathi, Michael

    2008-08-05

    A graphite oxide-intercalated anionic clay (nickel zinc hydroxysalt) has been prepared using the aqueous colloidal dispersions of negatively charged graphite oxide sheets and aminobenzoate-intercalated anionic clay layers as precursors. When the two colloidal dispersions are reacted, the interlayer aminobenzoate ions are displaced from the anionic clay and the negatively charged graphite oxide sheets are intercalated between the positively charged layers of the anionic clay. The thermal decomposition of the intercalated solid at different temperatures yields graphene-metal oxide/metal nanocomposites. Electron microscopic analysis of the composites indicates that the nanoparticles are intercalated between the layers of graphite in many regions of these solids although the graphite layers are largely exfoliated and not stacked well together.

  11. Preparation of novel polymer–metal oxide nanocomposites with nanophase separated hierarchical structure

    Indian Academy of Sciences (India)

    K Nam; Y Tsutsumi; C Yoshikawa; Y Tanaka; R Fukaya; T Kimura; H Kobayashi; T Hanawa; A Kishida

    2011-12-01

    This article deals with preparation of nanocomposite which comprised of nanophase separated structure of polymer chains and metal oxide. By grafting poly(hydroxyethyl methacrylate), poly(HEMA) on the surface of titanium which is covered by passive titanium oxide by atom transfer radical polymerization (ATRP) and executing anodic polarization, hierarchy nanophase separated structure with controlled thickness can be obtained. The titanium ions would be cationically charged and completely filled up the unoccupied binding sites of the polymer chains via electrochemical reaction, eventually covering the polymer chains with titanium oxide. However, this structure can be obtained when the anodic polarization is executed at initial applied voltage exceeding 10 VSCE. The control of thickness is possible by controlling the initial applied voltage. These results prove that the conventional polymer can form composite structure with metal oxide without using fillers or special polymers designed for composite.

  12. Metal oxide blended ZSM-5 nanocomposites as ethanol sensors

    Indian Academy of Sciences (India)

    MADHURI LAKHANE; RAJENDRA KHAIRNAR; MEGHA MAHABOLE

    2016-10-01

    Nano-ZSM-5 is synthesized without organic template via microwave-assisted hydrothermal technique. The synthesized nano-ZSM-5 zeolite is blended with metal oxides (ZnO and TiO$_2$) to have novel composites as ethanol sensors. The composites are characterized by X-ray diffraction (XRD) and Fourier transform infrared (FTIR) techniques. A study on ethanol sensing behaviour of metal oxide blended composite screen-printed thick films is carried out and the effect of metal oxide concentration on various ethanol sensing features, specifically operating temperature, response/recovery time and active region of the sensor, are investigated. XRD and FTIR confirm the blending of metal oxides in ZSM-5 matrix. Both, ZnO and TiO$_2$ blended, composite films are sensitive to ethanol. It can be concluded that metal oxide blending improves the preformance of sensor for ethanol detection. The response/recovery time and active sensing regions depend upon the concentration of metal oxide in host zeolite. The ZnO/ZSM-5 and TiO$_2$/ZSM-5 composite films are the excellent ethanol sensors.

  13. Synthesis and characterization of graphene oxide modified AgBr nanocomposites with enhanced photocatalytic activity and stability under visible light

    Science.gov (United States)

    Zhang, Du; Tang, Hua; Wang, Yuqi; Wu, Kongqiang; Huang, Hong; Tang, Guogang; Yang, Jin

    2014-11-01

    Novel visible-light-driven graphene oxide (GO)/AgBr nanocomposites were synthesized by a facile solution method. The GO/AgBr nanocomposites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoemission spectroscopy (XPS) analysis, UV-vis diffuse reflectance spectroscopy (DRS), Fourier transform infrared spectra (FTIR), and Raman spectra. The results indicated that AgBr nanoparticles were evenly distributed on the surface of GO and the heterostructures were formed. The photocatalytic activity of the as-prepared nanocomposites was evaluated by using Rhodamine B (RhB), Methylene blue (MB) and Methyl orange (MO) as target organic pollutants. The nanocomposites exhibit excellent photocatalytic activity for all of three dyes. Compared with bare AgBr particles, the GO/AgBr nanocomposites show better photocatalytic properties toward RhB pollutants. Additionally, the radical scavengers experiment indicated that O2rad - radicals was the main reactive species for the RhB degradation under visible light. The increased photocatalytic activity of the GO/AgBr nanocomposites was attributed to the strong coupling between GO and AgBr, which facilitated interfacial charge transfer and inhibited electron-hole recombination. A photocatalytic mechanism of GO/AgBr nanocomposites was also proposed.

  14. Polyaniline silver nanoparticle coffee waste extracted porous graphene oxide nanocomposite structures as novel electrode material for rechargeable batteries

    Science.gov (United States)

    Sundriyal, Poonam; Bhattacharya, Shantanu

    2017-03-01

    The exploration of new and advanced electrode materials are required in electronic and electrical devices for power storage applications. Also, there has been a continuous endeavour to formulate strategies for extraction of high performance electrode materials from naturally obtained waste products. In this work, we have developed an in situ hybrid nanocomposite from coffee waste extracted porous graphene oxide (CEPG), polyaniline (PANI) and silver nanoparticles (Ag) and have found this novel composite to serve as an efficient electrode material for batteries. The successful interaction among the three phases of the nano-composite i.e. CEPG-PANI-Ag have been thoroughly understood through RAMAN, Fourier transform infrared and x-ray diffraction spectroscopy, morphological studies through field emission scanning electron microscope and transmission electron microscope. Thermo-gravimetric analysis of the nano-composite demonstrates higher thermal stability up-to a temperature of 495 °C. Further BET studies through nitrogen adsorption-desorption isotherms confirm the presence of micro/meso and macro-pores in the nanocomposite sample. The cyclic-voltammetry (CV) analysis performed on CEPG-PANI-Ag nanocomposite exhibits a purely faradic behaviour using nickel foam as a current collector thus suggests the prepared nanocomposite as a battery electrode material. The nanocomposite reports a maximum specific capacity of 1428 C g-1 and excellent cyclic stability up-to 5000 cycles.

  15. Effects of natural zeolite and ferric oxide to electromagnetic and reflection loss properties of polyurethane nanocomposite

    Science.gov (United States)

    Gultom, G.; Wirjosentono, B.; Ginting, M.; Sebayang, K.

    2017-07-01

    Microwave-absorptive polymeric composite materials are becoming important to protect interference of any communication systems due to increasing use of microwave-inducing devices. In this work, the microwave-absorptive polyurethane nanocomposites were prepared using natural zeolites of Sarulla North Sumatra and commercial ferric oxide as fillers. Weight ratios of the polyurethane to natural zeolite and ferric oxide were varied (90%:6%:4%; 80%:12%:8%; 70%:24%:6%) by weight. The fillers were prepared using ball milling technique and characterized for their particle size distributions using Particle Size Analyzer. The nanocomposites, prepared using in-situ reaction of polyethylene glycol, toluene diisocyanate and fillers. The complex permittivity (ε’and ε”) and complex permeability (μ’ and μ”) as electromagnetic properties were calculated using NRW method after collecting real and imaginary S parameter using Vector Network Analyzer measurement at X band frequency. Results show ratio of the fillers will affect the permeability, permittivity and reflection loss of the materials. The best reflection loss was shown -40.588 dB (>99 % absorption) at ratio for polyurethane : nanozeolite : ferric oxide (80%:12%:8%) by weight observed at 10.92 GHz. According to the measurement and calculation was shown the polyurethane filled with natural nanozeolite and ferric oxide is a good electromagnetic wave attenuation material.

  16. Enhanced disinfection efficiency of mechanically mixed oxidants with free chlorine.

    Science.gov (United States)

    Son, Hyunju; Cho, Min; Kim, Jaeeun; Oh, Byungtaek; Chung, Hyenmi; Yoon, Jeyong

    2005-02-01

    To the best of our knowledge, this study is the first investigation to be performed into the potential benefits of mechanically mixed disinfectants in controlling bacterial inactivation. The purpose of this study was to evaluate the disinfection efficiency of mechanically mixed oxidants with identical oxidant concentrations, which were made by adding small amounts of subsidiary oxidants, namely ozone (O3), chlorine dioxide (ClO2), hydrogen peroxide (H2O2) and chlorite (ClO2(-)), to free available chlorine (Cl2), using Bacillus subtilis spores as the indicator microorganisms. The mechanically mixed oxidants containing Cl2/O3, Cl2/ClO2 and Cl2/ClO2(-) showed enhanced efficiencies (of up to 52%) in comparison with Cl2 alone, whereas no significant difference was observed between the mixed oxidant, Cl2/H2O2, and Cl2 alone. This enhanced disinfection efficiency can be explained by the synergistic effect of the mixed oxidant itself and the effect of intermediates such as ClO2(-)/ClO2, which are generated from the reaction between an excess of Cl2 and a small amount of O3/ClO2(-). Overall, this study suggests that mechanically mixed oxidants incorporating excess chlorine can constitute a new and moderately efficient method of disinfection.

  17. Enhancement of the thermo-mechanical properties and efficacy of mixing technique in the preparation of graphene/PVC nanocomposites compared to carbon nanotubes/PVC

    OpenAIRE

    Mudassir Hasan; Moonyong Lee

    2014-01-01

    Thin films of poly vinyl chloride (PVC)/multiwalled carbon nanotubes (MWCNT) and PVC/graphene (GN) nanocomposites were prepared by mixing in the presence of different quantities of nanoparticles. Film casting was performed using tetrahydrofuran as a solvent. The as-prepared PVC/MWCNT and PVC/GN nanocomposites were characterized by scanning electron microscopy, Raman spectroscopy, X-ray diffraction, thermogravimetric analysis, differential scanning calorimetry, dynamic mechanical analysis, and...

  18. Colloidal titania-silica-iron oxide nanocomposites and the effect from silica thickness on the photocatalytic and bactericidal activities

    Science.gov (United States)

    Chanhom, Padtaraporn; Charoenlap, Nisanart; Tomapatanaget, Boosayarat; Insin, Numpon

    2017-04-01

    New types of colloidal multifunctional nanocomposites that combine superparamagnetic character and high photocatalytic activity were synthesized and investigated. The superparamagnetic nanocomposites composed of anatase titania, silica, and iron oxide nanoparticles (TSI) were synthesized using thermal decomposition method followed by microemulsion method, without calcination at high temperature. Different techniques including X-ray diffraction (XRD) and transmission electron microscope (TEM) were used to characterize and confirm the structure of the nanocomposites. These nanocomposites showed high photocatalytic activity when used in the photodegradation of methylene blue under irradiation with a black light lamp. Moreover, the nanocomposites exhibited high antibacterial properties. From our study, the nanocomposites can be useful in various applications such as removal of pollutants with readily separation from the environment using an external magnetic field. These composites could effectively photo-degrade the dye at least three cycles without regeneration. The effects of silica shell thickness on the photocatalytic activity was investigated, and the thickness of 6 nm of the silica interlayer is enough for the inhibition of electron translocation between titania and iron oxide nanoparticles and maintaining the efficiency of photocatalytic activity of titania nanoparticles.

  19. Pulse electrodeposited nickel-indium tin oxide nanocomposite as an electrocatalyst for non-enzymatic glucose sensing

    Energy Technology Data Exchange (ETDEWEB)

    Sivasakthi, P.; Ramesh Bapu, G.N.K., E-mail: rameshbapugnk@cecri.res.in; Chandrasekaran, Maruthai

    2016-01-01

    Nickel and nickel-ITO nanocomposite on mild steel substrate were prepared by pulse electrodeposition method from nickel sulphamate electrolyte and were examined as electrocatalysts for non-enzymatic glucose sensing. The surface morphology, chemical composition, preferred orientation and oxidation states of the nickel metal ion in the deposits were characterized by SEM, EDAX, XRD and XPS. Electrochemical sensing of glucose was studied by cyclic voltammetry and amperometry. The modified Ni-ITO nanocomposite electrode showed higher electrocatalytic activity for the oxidation of glucose in alkaline medium and exhibited a linear range from 0.02 to 3.00 mM with a limit of detection 3.74 μM at a signal-to-noise ratio of 3. The higher selectivity, longer stability and better reproducibility of this electrode compared to nickel in the sensing of glucose are pointers for exploitation in practical clinical applications. - Highlights: • Ni-ITO nanocomposites are prepared by pulse electrocodeposition method from nickel sulphamate solutions. • Ni-ITO nanocomposites are characterized using SEM, EDAX, XRD and XPS. • Electrochemical characteristics of the Ni and Ni-ITO nanocomposite deposits are studied by CV and amperometry techniques. • Ni-ITO nanocomposite electrode could be used as sensing material for detection of glucose in practical condition.

  20. Processable conductive graphene/polyethylene nanocomposites: Effects of graphene dispersion and polyethylene blending with oxidized polyethylene on rheology and microstructure

    Energy Technology Data Exchange (ETDEWEB)

    Iqbal, Muhammad Z.; Abdala, Ahmed A.; Mittal, Vikas; Seifert, Sӧnke; Herring, Andrew M.; Liberatore, Matthew W.

    2016-08-01

    Poor dispersion of graphene in non-polar polymer matrices creates composites with limited applications. A method to improve the dispersion of graphene in polyethylene (PE) via blending PE with oxidized PE (OPE) is examined. Graphene was produced by simultaneous thermal exfoliation and reduction of graphite oxide. Nanocomposites of graphene with PE as well as graphene with PE/OPE-blends were prepared by solvent blending. Improved dispersion of graphene in PE/OPE blends substantially decreases percolation from both rheological (0.3 vol%) and electrical (0.13 vol%) measurements compared to neat PE nanocomposites (1 and 0.29 vol%), respectively. A universal Brownian dispersion of graphene in polymers was concluded similar to that of nanotubes, following the Doi-Edwards theory. Micromechanical models, such as Mori-Tanaka and Halpin-Tsai models, modeled the mechanical properties of the nanocomposites. The nanocomposites microstructure, studied by small angle x-ray scattering, confirmed better dispersion of graphene at lower loadings and the formation of surface fractals in the blend/graphene nanocomposites; whereas only mass fractals were observed in neat PE/graphene nanocomposites.

  1. On the elastic properties of single-walled carbon nanotubes/poly(ethylene oxide) nanocomposites using molecular dynamics simulations.

    Science.gov (United States)

    Rouhi, S; Alizadeh, Y; Ansari, R

    2016-01-01

    Molecular dynamics simulations are used to study the physical and mechanical properties of single-walled carbon nanotubes/poly(ethylene oxide) nanocomposites. The effects of nanotube atomic structure, diameter, and volume fraction on the polymer density distribution, polymer atom distribution, stress-strain curves of nanocomposites and Young's, and shear moduli of single-walled carbon nanotubes/poly(ethylene oxide) nanocomposites are explored. It is shown that the density of polymer, surrounding the nanotube surface, has a peak near the nanotube surface. However, increasing distance leads to dropping it to the value near the density of pure polymer. It is seen that for armchair nanotubes, the average polymer atoms distances from the single-walled carbon nanotubes are larger than the polymer atom distance from zigzag nanotubes. It further is shown that zigzag nanotubes are better candidates to reinforce poly (ethylene oxide) than their armchair counterparts.

  2. Amperometric Determination of Ascorbic Acid in Pharmaceutical Formulations by a Reduced Graphene Oxide-cobalt Hexacyanoferrate Nanocomposite

    Science.gov (United States)

    Heli, Hossein

    2015-01-01

    Investigation of the redox properties of drugs and their determination are performed by electrochemical techniques. Data obtained from electrochemical techniques are often correlated with molecular structure and pharmacological activity of drugs. In this regard, different modified electrodes were applied as sensors for quantification of different drugs. A nanocomposite of reduced graphene oxide-cobalt hexacyanoferrate was synthesized by a simple precipitation route. Scanning electron microscopy revealed that the nanocomposite comprised nanoparticles of cobalt hexacyanoferrate attached to the reduced graphene oxide nanosheets. A nanocomposite-modified carbon paste electrode was then fabricated. It represented prominent activity toward the electrocatalytic oxidation of ascorbic acid, and the kinetics of the electrooxidation process was evaluated. Finally, an amperometric method was developed for the quantification of ascorbic acid in different pharmaceutical formulations. PMID:25901152

  3. Polystyrene-graphene oxide (GO) nanocomposite synthesized by interfacial interactions between RAFT modified GO and core-shell polymeric nanoparticles.

    Science.gov (United States)

    Yeole, Niranjan; Kutcherlapati, S N Raju; Jana, Tushar

    2015-04-01

    Here we report simple and robust one-pot method for the preparation of polystyrene (PS)/graphene oxide (GO) nanocomposite using reversible addition fragmentation chain transfer (RAFT) modified GO in surfactant free emulsion polymerization (SFEP). The results suggested that ionic comonomer, styrene sulfonate sodium salt (SS-Na), concentration plays vital role in forming PS/GO nanocomposite. X-ray and electron diffraction studies suggest that there is no recombination of GO sheets when moderate SS-Na concentration is used, resulting complete exfoliation of GO sheets in the PS/GO nanocomposite. The formation of core-shell particles in which PS is the core and polystyrene sulfonate sodium salt (PSS-Na) is the shell, and the specific interactions between functional groups of GO and PSS-Na are attributed as the driving forces for the PS/GO nanocomposite formation.

  4. ZnO microspheres-reduced graphene oxide nanocomposite for photocatalytic degradation of methylene blue dye

    Science.gov (United States)

    Qin, Jiaqian; Zhang, Xinyu; Yang, Chengwu; Cao, Meng; Ma, Mingzhen; Liu, Riping

    2017-01-01

    In this work, ZnO microspheres-reduced graphene oxide (rGO) nanocomposites were synthesized via a simple solution method and used for the photodegradation of methylene blue (MB) dye from water under UV light. The SEM and TEM observations demonstrate that the microsphere morphologies of the ZnO microspheres-rGO nanocomposite is composed of ZnO microspheres anchored on rGO sheets, confirming the formation of ZnO microspheres-rGO composites. Raman spectra and X-ray photoelectron spectroscopy reveal that both of the reduction of GO tight contact between ZnO and rGO are achieved during the high temperature calcination process. During the photocatalytic test, in comparison with ZnO microspheres and P25 TiO2, the ZnO microspheres-rGO nanocomposite shows improved photodegradation of MB dye, because the rGO sheets could reduce the charge recombination in electron-transfer processes. According to the scavenger experiments, the possible MB degradation mechanism is contributed mainly to the generation of active species induced by the photogenerated holes (h+) and superoxide radicals (rad O2-).

  5. Attapulgite-CeO2/MoS2 ternary nanocomposite for photocatalytic oxidative desulfurization

    Science.gov (United States)

    Li, Xiazhang; Zhang, Zuosong; Yao, Chao; Lu, Xiaowang; Zhao, Xiaobing; Ni, Chaoying

    2016-02-01

    Novel attapulgite(ATP)-CeO2/MoS2 ternary nanocomposites were synthesized by microwave assisted assembly method. The structures of the nanocomposites were characterized by XRD, FT-IR, UV-vis, XPS and in situ TEM. The photocatalytic activities of ATP-CeO2/MoS2 composites were investigated by degradating dibenzothiophene (DBT) in gasoline under visible light irradiation. The effect of the mass ratio of CeO2 to MoS2 on photocatalytic activity was investigated. The results indicate that the three-dimensional network structure is firmly constructed by ATP skeleton, CeO2 particles and MoS2 nanosheet which effectively increase the surface area of the composites and promote the separation of electrons and holes by resulting electronic transmission channels of multi-channel in space. The degradation rate of DBT can reach 95% under 3 h irradiation when the mass ratio of CeO2/MoS2 is 4/10. A plausible mechanism for the photocatalytic oxidative desulfurization of this nanocomposite is put forward.

  6. Preparation and antibacterial properties of Ag@polydopamine/graphene oxide sheet nanocomposite

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Hao [Key Laboratory of Carbon Fiber and Functional Polymers of Ministry of Education, College of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029 (China); Liu, Yunfang, E-mail: liuyunfang@mail.buct.edu.cn [Key Laboratory of Carbon Fiber and Functional Polymers of Ministry of Education, College of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029 (China); Chi, Weidong [Key Laboratory of Carbon Fiber and Functional Polymers of Ministry of Education, College of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029 (China); Yu, Changyuan [College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029 (China); Yu, Yingjie [Department of Materials Science and Engineering, State University of New York, Stony Brook, NY 11794-2275 (United States)

    2013-10-01

    Immobilization of silver nanoparticles (Ag NPs) on poly-dopamine (PDA) functionalized graphene oxide sheets (GOSs) were carried out by an easy in situ reduction method. The PDA layer was coated on the surface of the GOSs via the self-polymerization of dopamine under atmosphere condition. The PDA layer not only works as the chemisorption and reduction sites for silver ions to form Ag NPs but also stabilizes them. High-resolution transmission electron microscopy observation shows that the average size of the Ag NPs anchored on the PDA/GOS composite is about 2.8 nm. The inhibition zone diameter of the Ag@PDA/GOS nanocomposite is about 23.7 mm, whereas said diameter of the Ag NPs is only 18.5 mm. The minimum bactericidal concentration of the Ag@PDA/GOS nanocomposite is about 25 μg/ml that is only half of said concentration of the Ag NPs. The Ag@PDA/GOS nanocomposite exhibits an excellent antibacterial property.

  7. Preparation of RHA-silica/graphene oxide nanocomposite for removal of nickel ions from water

    Science.gov (United States)

    Tien, Tran Thi Thuy; Tu, Tran Hoang; Thao, Huynh Nguyen Phuong; Hieu, Nguyen Huu

    2017-09-01

    In this study, silica was synthesized from rice husk ash (RHA-SiO2) by precipitation method. Graphene oxide (GO) was prepared by modified Hummers method. RHA-SiO2/GO nanocomposite was fabricated by in-situ one-step method using 3-Aminopropyltriethoxysilane (APS) as a coupling agent. The nanocomposite was characterized by using X-ray Fluorescence, X-ray diffraction, transmission electron microscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, and Brunauer-Emmett-Teller (BET) specific surface area. The adsorption of RHA-SiO2/GO for Ni2+ ions from water was investigated and compared with the precursors. Ultraviolet-visible (UV-Vis) spectroscopy was used to quantify the amount of the initial and the residual Ni2+ concentration. The maximum adsorption capacity of the nanocomposite for Ni2+ calculated from Langmuir isotherm model, which was 256.4 mg/g. In addition, the adsorption data were well-fitted to the pseudo-second-order kinetic equation. Accordingly, this study demonstrated that RHA-SiO2/GO could be used as a highly efficient adsorbent for removal Ni2+ ions from aqueous solution.

  8. Novel synthesis of tin oxide/graphene aerogel nanocomposites as anode materials for lithium ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Zheyu [College of Material Science and Engineering, Liaoning Technical University, Fuxin 123000 (China); Energy & Materials Engineering Centre, College of Physics and Materials Science, Tianjin Normal University, Tianjin 300387 (China); Li, Xifei, E-mail: xfli2011@hotmail.com [Energy & Materials Engineering Centre, College of Physics and Materials Science, Tianjin Normal University, Tianjin 300387 (China); Tai, Limin, E-mail: tailimin@163.com [College of Material Science and Engineering, Liaoning Technical University, Fuxin 123000 (China); Song, Haoze; Zhang, Yiyan; Yan, Bo; Fan, Linlin; Shan, Hui [Energy & Materials Engineering Centre, College of Physics and Materials Science, Tianjin Normal University, Tianjin 300387 (China); Li, Dejun, E-mail: dli1961@126.com [Energy & Materials Engineering Centre, College of Physics and Materials Science, Tianjin Normal University, Tianjin 300387 (China)

    2015-10-15

    A novel method of mechanical exfoliation followed by hydrothermal approach was proposed to synthesize the tin oxide/graphene aerogels (SnO{sub 2}/GAs) nanocomposites. Homogeneous distribution of SnO{sub 2} nanocrystals on GAs was confirmed by SEM, XRD and TEM characterization. It was found that optimized exfoliation of the SnS{sub 2} is the key factor to obtain high electrochemical lithiation/delithiation performance of the anodes. The as-prepared SnO{sub 2}/GA nanocomposites exhibited high reversible capacity (up to 1086.7 mAh g{sup −1} after 100 cycles) and excellent cycling stability. The improved rate capability was also obtained, for instance, the reversible capacity at a current density of 800 mA g{sup −1} is over 447.9 mAh g{sup −1}, and then recovered to as high as 784.4 mAh g{sup −1} at a current density of 100 mA g{sup −1}. - Highlights: • A novel approach was employed to synthesize the SnO{sub 2}/GA nanocomposites. • The designed SnO{sub 2}/GAs exhibited high reversible capacity and excellent cycling stability. • The volume change challenge of SnO{sub 2} was markedly alleviated by the GA matrix. • The novel synthesis method can be extended for other materials in lithium ion batteries.

  9. An organic indicator functionalized graphene oxide nanocomposite-based colorimetric assay for the detection of sarcosine

    Science.gov (United States)

    Xue, Zhonghua; Yin, Bo; Wang, Hui; Li, Mengqian; Rao, Honghong; Liu, Xiuhui; Zhou, Xinbin; Lu, Xiaoquan

    2016-03-01

    Rapid detection of sarcosine is a key requirement for both diagnosis and treatment of disease. We report here a simple yet sensitive colorimetric nanocomposite platform for rapid detection of sarcosine in alkaline media. The approach exploited the benefits of a rapid color-producing reaction between an organic indicator, 1,2-naphthoquinone-4-sulphonic acid sodium salt (NQS), and the analyte of sarcosine species as well as the good catalytic ability of graphene oxide (GO) to the formation of highly colored products due to its good water dispersibility, extremely large surface area and facile surface modification. As a result, a NQS functionalized GO nanocomposite through π-π stacking has been demonstrated to be useful as a highly efficient catalyst system for the selective and sensitive colorimetric determination of sarcosine by providing a nanocomposite-amplified colorimetric response. Meanwhile, the strategy offered excellent selectivity toward sarcosine species against other amino acids as well as a satisfying detection limit of 0.73 μM. More importantly, by using an electrochemical method, a credible sensing mechanism of GO nanocomposite-based colorimetric platform for a special analyte determination can be easily verified and elucidated, which also provides an attractive alternative to conventional characterization strategies.Rapid detection of sarcosine is a key requirement for both diagnosis and treatment of disease. We report here a simple yet sensitive colorimetric nanocomposite platform for rapid detection of sarcosine in alkaline media. The approach exploited the benefits of a rapid color-producing reaction between an organic indicator, 1,2-naphthoquinone-4-sulphonic acid sodium salt (NQS), and the analyte of sarcosine species as well as the good catalytic ability of graphene oxide (GO) to the formation of highly colored products due to its good water dispersibility, extremely large surface area and facile surface modification. As a result, a NQS

  10. Graphenated tantalum(IV) oxide and poly(4-styrene sulphonic acid)-doped polyaniline nanocomposite as cathode material in an electrochemical capacitor

    CSIR Research Space (South Africa)

    Njomo, N

    2014-05-01

    Full Text Available Nanostructured poly(4-styrene sulphonic acid) and tantalum (IV) oxide-doped polyaniline nanocomposite were synthesised and their electro-conductive properties were determined. The oxide was synthesized using a modified sol-gel method...

  11. Synthesis and characterization of composites of mixed oxides of iron and neodymium in polymer matrix of aniline–formaldehyde

    Indian Academy of Sciences (India)

    Sajdha; H N Sheikh; B L Kalsotra; N Kumar; S Kumar

    2011-07-01

    Nanocomposites of mixed oxides of iron and neodymium in polymer matrix of anilineformaldehyde are reported. The composites have been obtained by treating the aqueous solution of aniline, hydrochloric acid and formaldehyde with halide of iron and neodymium oxide. The infra-red spectra show broad peaks at ∼ 590 cm-1 and at ∼ 610 cm-1 due to the presence of oxides of both iron and neodymium. In heated samples, the absorption peaks due to metal oxides are better resolved. A broad and strong peak in XRD spectra at 2 value of 35.69920 corresponds to spinel -Fe2O3. 57Fe Mössbauer spectrum for unheated sample gives Mössbauer parameters, i.e. isomer shift (), quadrupole splitting ( ) and effective magnetic field (Heff). Transmission electron microscopy (TEM) micrographs reveal well dispersed particles at different magnifications. Vibrating sample magnetometry (VSM) studies indicate that the ferrite nanoparticles exhibit characteristics of ferromagnetism.

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

    Directory of Open Access Journals (Sweden)

    Wenkun Zhu

    2017-05-01

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

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

    Science.gov (United States)

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

    2017-01-01

    This study was inspired by the unique multi-scale and multi-level ‘brick-and-mortar’ (B&M) structure of nacre layers. We prepared the B&M, environmentally-friendly graphene oxide-carrageenan (GO-Car) nanocomposite films using the following steps. A natural polyhydroxy polymer, carrageenan, was absorbed on the surface of monolayer GO nanosheets through hydrogen-bond interactions. Following this, a GO-Car hybridized film was produced through a natural drying process. We conducted structural characterization in addition to analyzing mechanical properties and cytotoxicity of the films. Scanning electron microscope (SEM) and X-ray diffraction (XRD) analyses showed that the nanocomposite films had a similar morphology and structure to nacre. Furthermore, the results from Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and Thermogravimetric (TG/DTG) were used to explain the GO-Car interaction. Analysis from static mechanical testers showed that GO-Car had enhanced Young’s modulus, maximum tensile strength and breaking elongation compared to pure GO. The GO-Car nanocomposite films, containing 5% wt. of Car, was able to reach a tensile strength of 117 MPa. The biocompatibility was demonstrated using a RAW264.7 cell test, with no significant alteration found in cellular morphology and cytotoxicity. The preparation process for GO-Car films is simple and requires little time, with GO-Car films also having favorable biocompatibility and mechanical properties. These advantages make GO-Car nanocomposite films promising materials in replacing traditional petroleum-based plastics and tissue engineering-oriented support materials. PMID:28772897

  14. One-Pot Synthesis of Copper Sulfide Nanowires/Reduced Graphene Oxide Nanocomposites with Excellent Lithium-Storage Properties as Anode Materials for Lithium-Ion Batteries.

    Science.gov (United States)

    Feng, Caihong; Zhang, Le; Yang, Menghuan; Song, Xiangyun; Zhao, Hui; Jia, Zhe; Sun, Kening; Liu, Gao

    2015-07-29

    Copper sulfide nanowires/reduced graphene oxide (CuSNWs/rGO) nanocompsites are successfully synthesized via a facile one-pot and template-free solution method in a dimethyl sulfoxide (DMSO)-ethyl glycol (EG) mixed solvent. It is noteworthy that the precursor plays a crucial role in the formation of the nanocomposites structure. SEM, TEM, XRD, IR and Raman spectroscopy are used to investigate the morphological and structural evolution of CuSNWs/rGO nanocomposites. The as-fabricated CuSNWs/rGO nanocompsites show remarkably improved Li-storage performance, excellent cycling stability as well as high-rate capability compared with pristine CuS nanowires. It obtains a reversible capacity of 620 mAh g(-1) at 0.5C (1C = 560 mA g(-1)) after 100 cycles and 320 mAh g(-1) at a high current rate of 4C even after 430 cycles. The excellent lithium storage performance is ascribed to the synergistic effect between CuS nanowires and rGO nanosheets. The as-formed CuSNWs/rGO nanocomposites can effectively accommodate large volume changes, supply a 2D conducting network and trap the polysulfides generated during the conversion reaction of CuS.

  15. Characterization of magnetization-induced second harmonic generation in iron oxide polymer nanocomposites.

    Science.gov (United States)

    Vandendriessche, Stefaan; Valev, Ventsislav K; Verbiest, Thierry

    2012-01-10

    We have measured the magnetization-induced second harmonic generation (MSHG) of a nanocomposite consisting of iron oxide nanoparticles in a polymer film. The existing theoretical framework is extended to include DC magnetic fields in order to characterize the MSHG signal and analyze the measurements. Additionally, magnetic hysteresis loops are measured for four principal polarizer-analyzer configurations, revealing the P(IN)-P(OUT) and S(IN)-P(OUT) polarizer-analyzer configurations to be sensitive to the transverse magnetic field. These results demonstrate the use of MSHG and the applied formalism as a tool to study magnetic nanoparticles and their magnetic properties.

  16. Self-Assembled Epitaxial Au-Oxide Vertically Aligned Nanocomposites for Nanoscale Metamaterials.

    Science.gov (United States)

    Li, Leigang; Sun, Liuyang; Gomez-Diaz, Juan Sebastian; Hogan, Nicki L; Lu, Ping; Khatkhatay, Fauzia; Zhang, Wenrui; Jian, Jie; Huang, Jijie; Su, Qing; Fan, Meng; Jacob, Clement; Li, Jin; Zhang, Xinghang; Jia, Quanxi; Sheldon, Matthew; Alù, Andrea; Li, Xiaoqin; Wang, Haiyan

    2016-06-01

    Metamaterials made of nanoscale inclusions or artificial unit cells exhibit exotic optical properties that do not exist in natural materials. Promising applications, such as super-resolution imaging, cloaking, hyperbolic propagation, and ultrafast phase velocities have been demonstrated based on mostly micrometer-scale metamaterials and few nanoscale metamaterials. To date, most metamaterials are created using costly and tedious fabrication techniques with limited paths toward reliable large-scale fabrication. In this work, we demonstrate the one-step direct growth of self-assembled epitaxial metal-oxide nanocomposites as a drastically different approach to fabricating large-area nanostructured metamaterials. Using pulsed laser deposition, we fabricated nanocomposite films with vertically aligned gold (Au) nanopillars (∼20 nm in diameter) embedded in various oxide matrices with high epitaxial quality. Strong, broad absorption features in the measured absorbance spectrum are clear signatures of plasmon resonances of Au nanopillars. By tuning their densities on selected substrates, anisotropic optical properties are demonstrated via angular dependent and polarization resolved reflectivity measurements and reproduced by full-wave simulations and effective medium theory. Our model predicts exotic properties, such as zero permittivity responses and topological transitions. Our studies suggest that these self-assembled metal-oxide nanostructures provide an exciting new material platform to control and enhance optical response at nanometer scales.

  17. Green synthesis and photo-catalytic performances for ZnO-reduced graphene oxide nanocomposites.

    Science.gov (United States)

    Li, Xueshan; Wang, Qian; Zhao, Yibo; Wu, Wei; Chen, Jianfeng; Meng, Hong

    2013-12-01

    The zinc oxide (ZnO)-reduced graphene oxide (RGO) nanocomposites were greenly synthesized by one-step hydrothermal reaction with ZnCl2 and graphite oxide (GO) as precursors without extra reductant. The photo-catalytic performances consisting of the photo-degradation of Rhodamine B (RhB) and the photo-reduction of CO2 under the illumination of simulated solar light at ambient temperature were investigated. It was validated that the ZnO spherical particles assembled by ZnO nanorods with an average diameter of 150nm are uniformly deposited on the RGO sheets. Meanwhile, due to the introduction of RGO, the light adsorption scope of ZnO is enlarged, the size of ZnO is decreased, the degree of crystallinity is improved and the self-aggregation of the ZnO particles is effectively prevented. Comparing with the pure ZnO particles, the efficiency of the nanocomposites for the photo-degradation of RhB is increased by 39% and the yield of methanol from the reduction of CO2 is improved by 75%. The mechanisms that may explain the enhanced properties of as-synthesized ZnO-RGO for both the photo-degradation of RhB and the reduction of CO2 were also proposed.

  18. The tunable plasma synthesis of Pt-reduced graphene oxide nanocomposites

    Directory of Open Access Journals (Sweden)

    Yulong Ma

    2017-06-01

    Full Text Available Herein, we have developed Pt-plasma reduced graphene oxide (Pt/P-rGO catalysts displaying high overpotentials for methanol oxidation reaction (MOR through facile and tunable plasma treatments. We provide insight into the improved performance of these catalysts by combining electrochemical measurements with microscopic and spectroscopic characterization techniques. The analysis results showed that the Pt nanoparticles (NPs were successfully deposited on P-rGO. The deposition and uniformity of Pt NPs were influenced by tuning the discharge power of the plasma. The catalytic performance towards the methanol oxidation reaction is investigated. The Pt/P-rGO NPs composites under 100 W show the best electrocatalytic activity. These results were vital to the further application of graphene-based metal nanocomposites synthesized by plasma technology.

  19. Photoelectrocatalytic Oxidation of Formic Acid at Titania@Polyoxometalate/Gold Nanocomposite Material Modified Electrode.

    Science.gov (United States)

    Pandiyarajan, Chinnappan; Pandikumar, Alagarsamy; Ramaraj, Ramasamy

    2015-09-01

    Amine functionalized silicate sol-gel stabilized titania (P25)-polyoxometalate (PTA)-gold (Au) nanocomposite materials (APS/(P25-PTA-Au)(NCM)) were prepared by a simple chemical reduction method and were used to fabricate modified photoelectrode for the photoelectrocatalytic oxidation of formic acid. The APS/(P25-PTA-Au)(NCM) photoelectrode showed synergistic photoelectrocatalytic behavior towards the oxidation of formic acid. The photoresponse of the APS/(P25-PTA-Au)(NCM) modified photoelectrode was found to be higher when compared to the controlled photoelectrodes. The present study shows that the loading of Au(nps) on APS/P25-PTA is more beneficial to enhance the photoinduced interfacial charge transfer process, which leads to increased photocurrent generation. The present study concludes that the photoelectrocatalytic oxidation of formic acid at the APS/(P25-PTA-Au)(NCM) photoelectrode will boost the formic acid fuel cell performance.

  20. Gold Nanoparticle-Graphene Oxide Nanocomposites That Enhance the Device Performance of Polymer Solar Cells

    Directory of Open Access Journals (Sweden)

    Ming-Kai Chuang

    2014-01-01

    Full Text Available Metal nanoparticle-decorated graphene oxides are promising materials for use in various optoelectronic applications because of their unique plasmonic properties. In this paper, a simple, environmentally friendly method for the synthesis of gold nanoparticle-decorated graphene oxide that can be used to improve the efficiency of organic photovoltaic devices (OPVs is reported. Here, the amino acid glycine is employed as an environmentally friendly reducing reagent for the reduction of gold ions in the graphene oxide solutions. Transmission electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy, UV-Vis spectroscopy, and Raman spectroscopy are used to characterize the material properties of the resulting nanomaterials. Furthermore, these nanocomposites are employed as the anode buffer layer in OPVs to trigger surface plasmonic resonance, which improved the efficiency of the OPVs. The results indicate that such nanomaterials appear to have great potential for application in OPVs.

  1. Natural Fiber-Reinforced Hybrid Polymer Nanocomposites: Effect of Fiber Mixing and Nanoclay on Physical, Mechanical, and Biodegradable Properties

    Directory of Open Access Journals (Sweden)

    Md. Saiful Islam

    2015-01-01

    Full Text Available Combining two kinds of fibers is a potential way to improve the essential properties of natural fiber-reinforced hybrid polymer composites. Biocomposites produced from natural resources are experiencing an increase in interest due to their high demand in the market for manufacturing, in addition to environmental and sustainability issues. In this study, natural fiber-reinforced hybrid polymer nanocomposites were prepared from coir fiber, wood fiber, polypropylene, and montmorillonite nanoclay using a hot press technique. The effects of fiber mixing and montmorillonite on their physico-mechanical and biodegradable properties were subsequently investigated. Before being used, both the wood and the coir fibers were alkali-treated to reduce their hydrophilicity. The mechanical properties of the fabricated composites were measured using a universal tensile testing machine and found to be enhanced after fiber mixing and nanoclay incorporation. Fourier transform infrared spectra indicated that the characteristic peaks of the composites shifted after fiber mixing. A new peak around 470 cm-1 was observed in the case of the nanocomposites, which confirmed the interaction between the fiber, polymer, and montmorillonite (MMT. Scanning electron microscopic analysis revealed that MMT strongly improved the adhesion and compatibility between the fiber and polymer matrix. The combining of fibers improved the biodegradability and water absorption properties, while MMT addition had the reverse effect on the same properties of the composites.

  2. Integrated Ternary Bioinspired Nanocomposites via Synergistic Toughening of Reduced Graphene Oxide and Double-Walled Carbon Nanotubes.

    Science.gov (United States)

    Gong, Shanshan; Cui, Wei; Zhang, Qi; Cao, Anyuan; Jiang, Lei; Cheng, Qunfeng

    2015-12-22

    With its synergistic toughening effect and hierarchical micro/nanoscale structure, natural nacre sets a "gold standard" for nacre-inspired materials with integrated high strength and toughness. We demonstrated strong and tough ternary bioinspired nanocomposites through synergistic toughening of reduced graphene oxide and double-walled carbon nanotube (DWNT) and covalent bonding. The tensile strength and toughness of this kind of ternary bioinspired nanocomposites reaches 374.1 ± 22.8 MPa and 9.2 ± 0.8 MJ/m(3), which is 2.6 and 3.3 times that of pure reduced graphene oxide film, respectively. Furthermore, this ternary bioinspired nanocomposite has a high conductivity of 394.0 ± 6.8 S/cm and also shows excellent fatigue-resistant properties, which may enable this material to be used in aerospace, flexible energy devices, and artificial muscle. The synergistic building blocks with covalent bonding for constructing ternary bioinspired nanocomposites can serve as the basis of a strategy for the construction of integrated, high-performance, reduced graphene oxide (rGO)-based nanocomposites in the future.

  3. Graphene oxide/MnO2 nanocomposite as destructive adsorbent of nerve-agent simulants in aqueous media

    Science.gov (United States)

    Šťastný, Martin; Tolasz, Jakub; Štengl, Václav; Henych, Jiří; Žižka, David

    2017-08-01

    Graphene oxide/MnO2 nanocomposite was prepared by thermal hydrolysis of potassium permanganate (KMnO4) and 2-chloroacetamide aqueous solutions with graphene oxide (GO) suspension. The synthesized samples were characterized by specific surface area (BET) and porosity determination (BJH), X-ray Diffraction (XRD) and high-resolution electron microscopes (HRSEM, HRTEM). These nanocomposites were used in an experimental evaluation of their adsorption activity with nerve agent simulants dimethyl methyl phosphonate (DMMP) and triethyl phosphate (TEP) in aqueous media. The nanocomposites exhibited enhanced adsorptive degradation ability compared to pure manganese oxide (MnO2) and GO. The GO amount in the nanocomposites affected their degradation activity substantially. The best adsorption efficiency was observed for samples with moderate GO amount. Three methods were used to observe the mechanism of the nerve-agent simulants deactivation: Gas chromatography with mass spectrometry (GC-MS), High-Performance Liquid Chromatography (HPLC) and in situ Infrared spectroscopy (FTIR). It was shown that the hydrolysis on the surface of prepared nanocomposites yields volatile primary alcohols (methanol and ethanol) as the main hydrolysis products.

  4. Synthesis and characterization of sulfur-titanium dioxide nanocomposites for photocatalytic oxidation of cyanide using visible light irradiation

    Institute of Scientific and Technical Information of China (English)

    E.S.Baeissa

    2015-01-01

    A sol-gel method was used to prepare TiO2and sulfur-TiO2(S-TiO2)nanocomposites, which were characterized by N2 adsorption-desorption, X-ray diffraction, X-ray photoelectron spectroscopy, photoluminescene, ultraviolet visible and transmission electron microscopy measurements. The photocatalytic performance of TiO2 and S-TiO2nanocomposites, with respect to the photocatalytic oxidation of cyanide under visible light irradiation, was determined. The results reveal that S is well dispersed on the surface of TiO2 nanoparticles. Additionally, the surface area of the S-TiO2nano-composites was observed to be smaller than that of the TiO2nanoparticles because of blocked pores caused by doping with S. The S-TiO2nanocomposite (0.3 wt% S) exhibited the lowest band gap and the highest photocatalytic activity in the oxidation of cyanide. The photocatalytic performance of S-TiO2(0.3 wt% S) nanocomposites was stable, even after the fifth reuse of the nanoparticles for the oxidation of cyanide.

  5. Optical and electrical studies of cerium mixed oxides

    Science.gov (United States)

    Sherly, T. R.; Raveendran, R.

    2014-10-01

    The fast development in nanotechnology makes enthusiastic interest in developing nanomaterials having tailor made properties. Cerium mixed oxide materials have received great attention due to their UV absorption property, high reactivity, stability at high temperature, good electrical property etc and these materials find wide applications in solid oxide fuel cells, solar control films, cosmetics, display units, gas sensors etc. In this study cerium mixed oxide compounds were prepared by co-precipitation method. All the samples were doped with Zn (II) and Fe (II). Preliminary characterizations such as XRD, SEM / EDS, TEM were done. UV - Vis, Diffuse reflectance, PL, FT-IR, Raman and ac conductivity studies of the samples were performed.

  6. Optical and electrical studies of cerium mixed oxides

    Energy Technology Data Exchange (ETDEWEB)

    Sherly, T. R., E-mail: trsherly@gmail.com [Post Graduate Department of Physics, Sanathana Dharma College, Alappuzha, Kerala (India); Raveendran, R. [Nanoscience Research Laboratory, Sree Narayana College, Kollam, Kerala 691001 (India)

    2014-10-15

    The fast development in nanotechnology makes enthusiastic interest in developing nanomaterials having tailor made properties. Cerium mixed oxide materials have received great attention due to their UV absorption property, high reactivity, stability at high temperature, good electrical property etc and these materials find wide applications in solid oxide fuel cells, solar control films, cosmetics, display units, gas sensors etc. In this study cerium mixed oxide compounds were prepared by co-precipitation method. All the samples were doped with Zn (II) and Fe (II). Preliminary characterizations such as XRD, SEM / EDS, TEM were done. UV - Vis, Diffuse reflectance, PL, FT-IR, Raman and ac conductivity studies of the samples were performed.

  7. Electrospun mixed oxide photocatalysts to decompose dyes in water

    Science.gov (United States)

    Divya, Sherlyn

    In this work, four catalysts have been studied for their photocatalytic efficiency by testing each with methylene blue dye solution. Three catalysts were synthesized by the electrospinning method and then compared with the fourth commercially available catalyst for their photocatalytic activity. The basic metal oxide studied was titanium dioxide. Nanocomposite mats of pure titania, copper doped titania and copper doped degussa P25 titania, were synthesized using the electrospinning method. The pure titania and copper doped titania nanocomposites possessed the anatase phase which was obtained by annealing the as-spun nanocomposites at 4500C. All the catalysts were analyzed for their photocatalytic activity both under ultra-violet light and under visible light. The aim of this work was to synthesize titania photocatalysts, demonstrate their photocatalytic activity with methylene blue solution under UV-light and visible light and compare their activities with the commercial titanium dioxide (degussa P25). It is important to synthesize visible light active photocatalysts as these could be activated under a wide spectrum of natural sunlight unlike the degussa titanium dioxide. Doping was incorporated in order to narrow the band gap energy of the photocatalyst for achieving higher efficiency especially under visible light irradiation. The morphology and size of the synthesized photocatalysts were studied by characterizing them with Scanning Electron Microscopy, Energy Dispersive X-Ray Spectroscopy, Transmission Electron Microscopy and X-Ray Diffraction. The photocatalytic activity tests were carried out using UV-Vis Spectroscopy. It was found that the electrospun pure titania and copper doped titania fibers were activated under the visible light spectrum unlike the degussa titanium dioxide. The copper doped titania provided to be the most efficient photocatalyst under visible light radiation and the importance of this finding can be extended for treating industrial

  8. Facile synthesis of pectin-stabilized magnetic graphene oxide Prussian blue nanocomposites for selective cesium removal from aqueous solution.

    Science.gov (United States)

    Kadam, Avinash A; Jang, Jiseon; Lee, Dae Sung

    2016-09-01

    This work focused on the development of pectin-stabilized magnetic graphene oxide Prussian blue (PSMGPB) nanocomposites for removal of cesium from wastewater. The PSMGPB nanocomposite showed an improved adsorption capacity of 1.609mmol/g for cesium, compared with magnetic graphene oxide Prussian blue, magnetic pectin Prussian blue, and magnetic Prussian blue nanocomposites, which exhibited adsorption capacities of 1.230, 0.901, and 0.330mmol/g, respectively. Increased adsorption capacity of PSMGPB nanocomposites was attributed to the pectin-stabilized separation of graphene oxide sheets and enhanced distribution of magnetites on the graphene oxide surface. Scanning electron microscopy images showed the effective separation of graphene oxide sheets due to the incorporation of pectin. The optimum temperature and pH for adsorption were 30°C and 7.0, respectively. A thermodynamic study indicated the spontaneous and the exothermic nature of cesium adsorption. Based on non-linear regression, the Langmuir isotherm fitted the experimental data better than the Freundlich and Tempkin models. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Synthesis and Electrochemical Properties of Nitrogen-Doped Graphene (NG)/Nickle Oxide (NiO) Nanocomposite for Supercapacitor.

    Science.gov (United States)

    Chen, C N; Ma, T; Zhang, Q; Fan, W; Fu, X W; Wang, Z B

    2015-12-01

    A novel nitrogen-doped graphene (NG)/nickle oxide (NiO) nanocomposite was synthesized by a facile two-step method, where NiO particles were dispersed on the surface of NG. The NG/NiO nanocomposite is characterized by using field-emission scanning electron microscopy (FE-SEM), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and Raman spectroscopy. The electrochemical properties of NG/NiO nanocomposite have been studied using cyclic voltammetry (CV), galvanostatic charge/discharge and electrochemical impedance spectroscopy (EIS) techniques. Compared with the nitrogen-doped graphene, the electrode prepared by NG/NiO nanocomposite has a mass specific capacitance of 342 F g(-1) at scan rate of 5 mV s(-1), which is much higher than that of nitrogen-doped graphene (NG). The galvanostatic charge/discharge results show this new kind nanocomposite has high specific capacitance with 320 F g(-1) in the range of 0.1-0.5 V at a current density of 1 A g(-1). The enhanced supercapacitive performance of NG/NiO nanocomposite suggesting its promising potential in supercapacitors.

  10. Ferroferric oxide/polystyrene (Fe3O4/PS superparamagnetic nanocomposite via facile in situ bulk radical polymerization

    Directory of Open Access Journals (Sweden)

    2010-03-01

    Full Text Available Organo-modified ferroferric oxide superparamagnetic nanoparticles, synthesized by the coprecipitation of superparamagnetic nanoparticles in presence of oleic acid (OA, were incorporated in polystyrene (PS by the facile in situ bulk radical polymerization by using 2,2-azobisisobutyronitrile (AIBN as initiator. The transmission electron microscopy (TEM analysis of the resultant uniform ferroferric oxide/polystyrene superparamagnetic nanocomposite (Fe3O4/PS showed that the superparamagnetic nanoparticles had been dispersed homogeneously in the polymer matrix due to the surface grafted polystyrene, confirmed by Fourier transform infrared (FT-IR spectroscopy and thermogravimetric analysis (TGA. The superparamagnetic property of the Fe3O4/PS nanocomposite was testified by the vibrating sample magnetometer (VSM analysis. The strategy developed is expected to be applied for the large-scale industrial manufacturing of the superparamagnetic polymer nanocomposite.

  11. Graphene Oxide Reinforced Polycarbonate Nanocomposite Films with Antibacterial Properties

    Directory of Open Access Journals (Sweden)

    R. Mahendran

    2016-01-01

    Full Text Available The incorporation of carbonaceous nanofillers into polymers can result in significant materials with improved physicochemical properties and novel composite functionalities. In this study, we have fabricated antibacterial, lightweight, transparent, and flexible graphene oxide (GO reinforced polycarbonate thin films by a facile and low-cost methodology. Solution blending is employed to get a homogeneous mixture of PC-GO composites at various loading of GO, and the thin films are prepared by dry-wet phase inversion technique. Thermal studies and micrographs of the films revealed the incorporation of GO in PC matrix. Microstructure of the thin films showed the homogeneous dispersion of GO at micro- and nanoscales; however, at higher loading of GO (0.7%, significant agglomeration is observed. More importantly, PC-GO composite films exhibited excellent antibacterial activities against E. coli and S. aureus, owing to the antibacterial nature of GO nanoparticles.

  12. Synthesis and characterization of graphene oxide modified AgBr nanocomposites with enhanced photocatalytic activity and stability under visible light

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Du [School of Materials Science and Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013 (China); Tang, Hua, E-mail: tanghua@mail.ujs.edu.cn [School of Materials Science and Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013 (China); Wang, Yuqi; Wu, Kongqiang; Huang, Hong [School of Materials Science and Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013 (China); Tang, Guogang [Department of Chemical Engineering, Zhenjiang College, Zhenjiang, Jiangsu 212003 (China); Yang, Jin [School of Materials Science and Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013 (China)

    2014-11-15

    Highlights: • GO/AgBr nanocomposites were prepared successfully. • There exists some synergistic effect between components in the composites. • The composites show high photocatalytic activity toward RhB, MB and MO degradation under visible light. - Abstract: Novel visible-light-driven graphene oxide (GO)/AgBr nanocomposites were synthesized by a facile solution method. The GO/AgBr nanocomposites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoemission spectroscopy (XPS) analysis, UV–vis diffuse reflectance spectroscopy (DRS), Fourier transform infrared spectra (FTIR), and Raman spectra. The results indicated that AgBr nanoparticles were evenly distributed on the surface of GO and the heterostructures were formed. The photocatalytic activity of the as-prepared nanocomposites was evaluated by using Rhodamine B (RhB), Methylene blue (MB) and Methyl orange (MO) as target organic pollutants. The nanocomposites exhibit excellent photocatalytic activity for all of three dyes. Compared with bare AgBr particles, the GO/AgBr nanocomposites show better photocatalytic properties toward RhB pollutants. Additionally, the radical scavengers experiment indicated that O{sub 2}·{sup −} radicals was the main reactive species for the RhB degradation under visible light. The increased photocatalytic activity of the GO/AgBr nanocomposites was attributed to the strong coupling between GO and AgBr, which facilitated interfacial charge transfer and inhibited electron-hole recombination. A photocatalytic mechanism of GO/AgBr nanocomposites was also proposed.

  13. Synthesis of Polyaniline-Coated Graphene Oxide@SrTiO3 Nanocube Nanocomposites for Enhanced Removal of Carcinogenic Dyes from Aqueous Solution

    Directory of Open Access Journals (Sweden)

    Syed Shahabuddin

    2016-09-01

    Full Text Available The present investigation highlights the synthesis of polyaniline (PANI-coated graphene oxide doped with SrTiO3 nanocube nanocomposites through facile in situ oxidative polymerization method for the efficient removal of carcinogenic dyes, namely, the cationic dye methylene blue (MB and the anionic dye methyl orange (MO. The presence of oxygenated functional groups comprised of hydroxyl and epoxy groups in graphene oxide (GO and nitrogen-containing functionalities such as imine groups and amine groups in polyaniline work synergistically to impart cationic and anionic nature to the synthesised nanocomposite, whereas SrTiO3 nanocubes act as spacers aiding in segregation of GO sheets, thereby increasing the effective surface area of nanocomposite. The synthesised nanocomposites were characterised by field emission scanning electron microscopy (FESEM, transmission electron microscopy (TEM, thermogravimetric analysis (TGA, X-ray diffraction (XRD, and Fourier transform infrared spectroscopy (FTIR. The adsorption efficiencies of graphene oxide (GO, PANI homopolymer, and SrTiO3 nanocubes-doped nanocomposites were assessed by monitoring the adsorption of methylene blue and methyl orange dyes from aqueous solution. The adsorption efficiency of nanocomposites doped with SrTiO3 nanocubes were found to be of higher magnitude as compared with undoped nanocomposite. Moreover, the nanocomposite with 2 wt % SrTiO3 with respect to graphene oxide demonstrated excellent adsorption behaviour with 99% and 91% removal of MB and MO, respectively, in a very short duration of time.

  14. Amine functionalized graphene oxide/CNT nanocomposite for ultrasensitive electrochemical detection of trinitrotoluene.

    Science.gov (United States)

    Sablok, Kavita; Bhalla, Vijayender; Sharma, Priyanka; Kaushal, Roohi; Chaudhary, Shilpa; Suri, C Raman

    2013-03-15

    Binding of electron-deficient trinitrotoluene (TNT) to the electron rich amine groups on a substrate form specific charge-transfer Jackson-Meisenheimer (JM) complex. In the present work, we report formation of specific JM complex on amine functionalized reduced graphene oxide/carbon nanotubes- (a-rGO/CNT) nanocomposite leading to sensitive detection of TNT. The CNT were dispersed using graphene oxide that provides excellent dispersion by attaching to CNT through its hydrophobic domains and solubilizes through the available OH and COOH groups on screen printed electrode (SPE). The GO was reduced electrochemically to form reduced graphene that remarkably increases electrochemical properties owing to the intercalation of high aspect CNT on graphene flakes as shown by TEM micrograph. The surface amine functionalization of dropcasted and rGO/CNT was carried out using a bi-functional cross linker ethylenediamine. The extent of amine functionalization on modified electrodes was confirmed using energy dispersive X-ray (EDX), X-ray photoelectron spectroscopy (XPS) and confocal microscopy. The FTIR and Raman spectra further suggested the formation of JM complex between amine functionalized electrodes and TNT leading to a shift in peak intensity together with peak broadening. The a-rGO/CNT nanocomposite prepared electrode surface leads to ultra-trace detection of TNT upto 0.01 ppb with good reproducibility (n=3). The a-rGO/CNT sensing platform could be an alternate for sensitive detection of TNT explosive for various security and environmental applications.

  15. A Room Temperature Nitric Oxide Gas Sensor Based on a Copper-Ion-Doped Polyaniline/Tungsten Oxide Nanocomposite

    Science.gov (United States)

    Wang, Shih-Han; Shen, Chi-Yen; Su, Jian-Ming; Chang, Shiang-Wen

    2015-01-01

    The parts-per-billion-level nitric oxide (NO) gas sensing capability of a copper-ion-doped polyaniline/tungsten oxide nanocomposite (Cu2+/PANI/WO3) film coated on a Rayleigh surface acoustic wave device was investigated. The sensor developed in this study was sensitive to NO gas at room temperature in dry nitrogen. The surface morphology, dopant distribution, and electric properties were characterized using scanning electron microscopy, energy-dispersive X-ray spectroscopy mapping, and Hall effect measurements, respectively. The Cu2+/PANI/WO3 film exhibited high NO gas sensitivity and selectivity as well as long-term stability. At 1 ppb of NO, a signal with a frequency shift of 4.3 ppm and a signal-to-noise ratio of 17 was observed. The sensor exhibited distinct selectivity toward NO gas with no substantial response to O2, NH3 and CO2 gases. PMID:25811223

  16. A Room Temperature Nitric Oxide Gas Sensor Based on a Copper-Ion-Doped Polyaniline/Tungsten Oxide Nanocomposite

    Directory of Open Access Journals (Sweden)

    Shih-Han Wang

    2015-03-01

    Full Text Available The parts-per-billion-level nitric oxide (NO gas sensing capability of a copper-ion-doped polyaniline/tungsten oxide nanocomposite (Cu2+/PANI/WO3 film coated on a Rayleigh surface acoustic wave device was investigated. The sensor developed in this study was sensitive to NO gas at room temperature in dry nitrogen. The surface morphology, dopant distribution, and electric properties were characterized using scanning electron microscopy, energy-dispersive X-ray spectroscopy mapping, and Hall effect measurements, respectively. The Cu2+/PANI/WO3 film exhibited high NO gas sensitivity and selectivity as well as long-term stability. At 1 ppb of NO, a signal with a frequency shift of 4.3 ppm and a signal-to-noise ratio of 17 was observed. The sensor exhibited distinct selectivity toward NO gas with no substantial response to O2, NH3 and CO2 gases.

  17. A room temperature nitric oxide gas sensor based on a copper-ion-doped polyaniline/tungsten oxide nanocomposite.

    Science.gov (United States)

    Wang, Shih-Han; Shen, Chi-Yen; Su, Jian-Ming; Chang, Shiang-Wen

    2015-03-24

    The parts-per-billion-level nitric oxide (NO) gas sensing capability of a copper-ion-doped polyaniline/tungsten oxide nanocomposite (Cu(2+)/PANI/WO3) film coated on a Rayleigh surface acoustic wave device was investigated. The sensor developed in this study was sensitive to NO gas at room temperature in dry nitrogen. The surface morphology, dopant distribution, and electric properties were characterized using scanning electron microscopy, energy-dispersive X-ray spectroscopy mapping, and Hall effect measurements, respectively. The Cu(2+)/PANI/WO3 film exhibited high NO gas sensitivity and selectivity as well as long-term stability. At 1 ppb of NO, a signal with a frequency shift of 4.3 ppm and a signal-to-noise ratio of 17 was observed. The sensor exhibited distinct selectivity toward NO gas with no substantial response to O2, NH3 and CO2 gases.

  18. Effects of the alkylamine functionalization of graphene oxide on the properties of polystyrene nanocomposites

    Science.gov (United States)

    2014-01-01

    Alkylamine-functionalized graphene oxides (FGOs) have superior dispersibility in low-polar solvents and, as a result, they interact with low-polar polymers such as polystyrene. In this work, the functionalization of graphene oxide using three types of alkylamines, octylamine (OA), dodecylamine (DDA), and hexadecylamine (HDA), was performed, and nanocomposites of polystyrene (PS) and FGOs were prepared via solution blending. Different dispersions of FGOs over PS were obtained for the three alkylamines, and the properties of the PS composites were influenced by the length of the alkylamine. A better thermal stability was observed with a longer chain length of the alkylamine. On the other hand, functionalization with the shortest chain length alkylamine resulted in the highest increase in the storage modulus (3,640 MPa, 140%) at a 10 wt.% loading of FGO. PMID:24936163

  19. Synthesis, characterization and photocatalytic activity of visible-light-driven reduced graphene oxide-CeO2 nanocomposite

    Science.gov (United States)

    Kaur, J.; Anand, K.; Anand, K.; Thangaraj, R.; Singh, R. C.

    2016-10-01

    Reduced graphene oxide (RGO) and CeO2 nanocomposite fabricated by a facile hydrothermal method was studied as a photocatalyst for the degradation of methylene blue (MB) under natural sunlight. The reduction of graphene oxide and decoration of CeO2 nanocubes was accomplished simultaneously in one hydrothermal step. The structural, optical and photocatalytic properties of synthesized samples were probed by X-ray diffraction, Raman spectroscopy, field-emission scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, UV-Vis diffuse reflectance spectra and photoluminescence spectra. RGO/CeO2 nanocomposite exhibited distinctive structural features comprising well-dispersed CeO2 nanocubes on the RGO surface without any agglomeration. RGO/CeO2 nanocomposite displayed a great MB absorptivity, significant band gap narrowing and photoluminescence quenching phenomenon concurrently, which was ascribed to unique properties of RGO sheets. The photocatalytic activity results revealed that there was a remarkable enhancement in reaction rate with RGO/CeO2 nanocomposite in comparison to its counterparts (Blank CeO2 and CNT/CeO2 nanocomposite). The degradation efficiency of RGO/CeO2, CNT/CeO2 and CeO2 was found to be 91.2, 75 and 64 % within 180 min respectively.

  20. Development of glucose biosensors based on plasma polymerization-assisted nanocomposites of polyaniline, tin oxide, and three-dimensional reduced graphene oxide

    Science.gov (United States)

    Wu, Shide; Su, Fangfang; Dong, Xiaodong; Ma, Chuang; Pang, Long; Peng, Donglai; Wang, Minghua; He, Linghao; Zhang, Zhihong

    2017-04-01

    A biosensor based on the plasma polyaniline (pPANI)-modified tin oxide and 3D reduced graphene oxide (SnO2@3D-rGO) nanocomposite was fabricated to detect glucose. The SnO2@3D-rGO nanocomposite was synthesized by simultaneously reducing 3D graphene oxide (3D-GO) and translating SnCl4 into SnO2, followed by pPANI modification. The content of amino groups in the SnO2@3D-rGO@pPANI nanocomposites depended on the plasma input powers used in plasma deposition. The SnO2@3D-rGO nanocomposite was important in the electrochemical biosensor to detect glucose. The fabricated biosensor exhibited a much higher sensitivity than that formed from individual components, namely, SnO2@3D-rGO and pPANI. This biosensor demonstrated a low detection limit of 0.047 ng mL-1 (0.26 nM) (S/N = 3) within the concentration range of 0.1 ng mL-1 to 5 μg mL-1. The selectivity, stability, and practicality of the SnO2@3D-rGO@pPANI-based biosensor were observed. In conclusion, the plasma surface-modified nanocomposite is a promising candidate as biosensor for glucose detection and biological diagnosis.

  1. Straightforward synthesis of hyperbranched polymer/graphene nanocomposites from graphite oxide via in situ grafting from approach

    Indian Academy of Sciences (India)

    Qiuhong Xu; Yiwen Gong; Yuan Fang; Guohua Jiang; Yin Wang; Xinke Sun; Rijing Wang

    2012-10-01

    The grafting of graphite oxide (GO) with cyclic ether monomers, directly affords grafting with hyperbranched polymers. The resulting nanocomposites show good solubility in the solvents of polymers, exfoliation of graphene in the polymer matrix and excellent mechanical properties and robustness under bending.

  2. Supercapacitive properties of symmetry and the asymmetry two electrode coin type supercapacitor cells made from MWCNTS/nickel oxide nanocomposite

    CSIR Research Space (South Africa)

    Adekunle, AS

    2011-10-01

    Full Text Available Supercapacitive properties of synthesised nickel oxides (NiO) nanoparticles integrated with multi-walled carbon nanotubes (MWCNT) in a two-electrode coin cell type supercapacitor were investigated. Successful formation of the MWCNT-NiO nanocomposite...

  3. Simultaneous electrochemical determination of dopamine and paracetamol on multiwalled carbon nanotubes/graphene oxide nanocomposite-modified glassy carbon electrode.

    Science.gov (United States)

    Cheemalapati, Srikanth; Palanisamy, Selvakumar; Mani, Veerappan; Chen, Shen-Ming

    2013-12-15

    In the present study, multiwalled carbon nanotubes (MWCNT)/graphene oxide (GO) nanocomposite was prepared by homogenous dispersion of MWCNT and GO and used for the simultaneous voltammetric determination of dopamine (DA) and paracetamol (PA). The TEM results confirmed that MWCNT walls were wrapped well with GO sheets. The MWCNT/GO nanocomposite showed superior electrocatalytic activity towards the oxidation of DA and PA, when compared with either pristine MWCNT or GO. The major reason for the efficient simultaneous detection of DA and PA at nanocomposite was the synergistic effect between MWCNT and GO. The electrochemical oxidation of DA and PA was investigated by cyclic voltammetry, differential pulse voltammetry and amperometry. The nanocomposite modified electrode showed electrocatalytic oxidation of DA and PA in the linear response range from 0.2 to 400 µmol L(-1) and 0.5 to 400 µmol L(-1) with the detection limit of 22 nmol L(-1) and 47 nmol L(-1) respectively. The proposed sensor displayed good selectivity, sensitivity, stability with appreciable consistency and precision.

  4. Preparation and characterizations of BiVO₄/reduced graphene oxide nanocomposites with higher visible light reduction activities.

    Science.gov (United States)

    Wang, Aolan; Shen, Song; Zhao, Yibo; Wu, Wei

    2015-05-01

    Bismuth vanadate/reduced graphene oxide (BiVO4/RGO) composites were synthesized by one-step hydrothermal method with graphite oxide, Bi(NO3)3 and NH4VO3 as precursors. The as-synthesized nanocomposites were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, UV-Vis spectroscopy (UV), fluorescence spectroscopy (FL) and electrochemical impedance spectroscopy (EIS). The reduced graphene oxide sheets were decorated by butterfly-like BiVO4 lamellas. Such combination not only alleviated the agglomeration of BiVO4 particles but also restrained the restacking of reduced graphene oxide. A preliminary study on the photo-reductions of Cr (VI) and CO2 under the illumination of simulated sunlight with as-synthesized BiVO4/RGO nanocomposites as catalyst was carried out. The nanocomposites showed better photo-catalytic activity than the conventional BiVO4 particles. The photo-reduction efficiency of BiVO4/RGO nanocomposites increased about 50.1% and the ethanol yield improved about 15.4 μmol/g-cat comparing with pure BiVO4. The enhancements of the photo-catalytic activities were attributed to the effective charge transfer of photo-generated electron from BiVO4 to RGO and improved absorption performance.

  5. The effect of material composition of 3-dimensional graphene oxide and self-doped polyaniline nanocomposites on DNA analytical sensitivity.

    Science.gov (United States)

    Yang, Tao; Chen, Huaiyin; Yang, Ruirui; Wang, Xinxing; Nan, Fuxin; Jiao, Kui

    2015-09-01

    Until now, morphology effects of 2-dimensional or 3-dimensional graphene nanocomposites and the effect of material composition on the biosensors have been rarely reported. In this paper, the various nanocomposites based on graphene oxide and self-doped polyaniline nanofibres for studying the effect of morphology and material composition on DNA sensitivity were directly reported. The isolation and dispersion of graphene oxide were realized via intercalated self-doped polyaniline and ultrasonication, where the ultrasonication prompts the aggregates of graphite oxide to break up and self-doped polyaniline to diffuse into the stacked graphene oxide. Significant electrochemical enhancement has been observed due to the existence of self-doped polyaniline, which bridges the defects for electron transfer and, in the mean time, increases the basal spacing between graphene oxide sheets. Different morphologies can result in different ssDNA surface density, which can further influence the hybridization efficiency. Compared with 2-dimensional graphene oxide, self-doped polyaniline and other morphologies of nanocomposites, 3-dimensional graphene oxide-self-doped polyaniline nanowalls exhibited the highest surface density and hybridization efficiency. Furthermore, the fabricated biosensors presented the broad detection range with the low detection limit due to the specific surface area, a large number of electroactive species, and open accessible space supported by nanowalls.

  6. Synthesis and Study of Optical properties of MgO based TM oxide (TM=Cu, Mn and Zn) nanocomposites

    Science.gov (United States)

    Tamizh Selvi, K.; Alamelumangai, K.; Priya, M.; Rathnakumari, M.; Kumar, P. Suresh; Sagadevan, Suresh

    2016-11-01

    A nanocomposite of MgO based transition metal (TM) oxide (TM=Zn, Mn, and Cu) was synthesized using sol-gel method. The powder x-ray diffraction confirmed the phase purity and particle size. The surface morphology and elemental composition were examined by High resolution scanning electron microscopy and energy-dispersive x-ray spectroscopy. The change in optical band gap of the synthesized nanocomposites, by increasing the Mg content was determined using UV-vis spectra and the luminescent properties were analyzed using photoluminescence spectra.

  7. FACILE REGULATION OF GLUTARALDEHYDE-MODIFIED GRAPHENE OXIDE FOR PREPARING FREE-STANDING PAPERS AND NANOCOMPOSITE FILMS

    Institute of Scientific and Technical Information of China (English)

    Ye-qiang Tan; Yi-hu Song; Qiang Zheng

    2013-01-01

    Colloidal suspensions of glutaraldehyde (GA) crosslinked or grafted graphene oxide (GO) sheets were fabricated by simply tailoring the feed sequence.The different structures were confirmed by Fourier transform infrared spectra and X-ray diffraction.As demonstration of the utilities,the different colloidal suspensions were used to prepare free-standing papers by flow-directed filtration and poly(vinyl alcohol) (PVA)-based nanocomposite films by casting.Free-standing papers from GA crosslinked GO sheets exhibited better mechanical properties than unmodified GO paper,while nanocomposite films from GA grafted GO exhibit higher tensile strength and Young's modulus.

  8. Influences of graphene oxide support on the electrochemical performances of graphene oxide-MnO2 nanocomposites

    Directory of Open Access Journals (Sweden)

    Xi Lifei

    2011-01-01

    Full Text Available Abstract MnO2 supported on graphene oxide (GO made from different graphite materials has been synthesized and further investigated as electrode materials for supercapacitors. The structure and morphology of MnO2-GO nanocomposites are characterized by X-ray diffraction, X-ray photoemission spectroscopy, scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, and Nitrogen adsorption-desorption. As demonstrated, the GO fabricated from commercial expanded graphite (denoted as GO(1 possesses more functional groups and larger interplane gap compared to the GO from commercial graphite powder (denoted as GO(2. The surface area and functionalities of GO have significant effects on the morphology and electrochemical activity of MnO2, which lead to the fact that the loading amount of MnO2 on GO(1 is much higher than that on GO(2. Elemental analysis performed via inductively coupled plasma optical emission spectroscopy confirmed higher amounts of MnO2 loading on GO(1. As the electrode of supercapacitor, MnO2-GO(1 nanocomposites show larger capacitance (307.7 F g-1 and better electrochemical activity than MnO2-GO(2 possibly due to the high loading, good uniformity, and homogeneous distribution of MnO2 on GO(1 support.

  9. Preferable removal of phosphate from water using hydrous zirconium oxide-based nanocomposite of high stability.

    Science.gov (United States)

    Chen, Liang; Zhao, Xin; Pan, Bingcai; Zhang, Weixian; Hua, Ming; Lv, Lu; Zhang, Weiming

    2015-03-02

    In this study, we employed a new nanocomposite adsorbent HZO-201, which featured high stability under varying solution chemistry, for preferable removal of phosphate from synthetic solution and a real effluent. An anion exchange resin (D-201) was employed as the host of HZO-201, where nano-hydrous zirconium oxide (HZO) was encapsulated as the active species. D-201 binds phosphate through nonspecific electrostatic affinity, whereas the loaded HZO nanoparticles capture phosphate through formation of the inner-sphere complexes. Quantitative contribution of both species to phosphate adsorption was predicted based on the double-Langmuir model. Preferable removal of phosphate by HZO-201 was observed in the presence of the competing anions at higher levels (Cl(-), NO3(-), SO4(2-), HCO3(-)). Fixed-bed adsorption indicated that the effective volume capacity of a synthetic water (2.0 mg P-PO4(3-)/L) by using HZO-201 was ∼1600 BV in the first run (<0.5mg P-PO4(3-)/L), comparable to Fe(III)-based nanocomposite HFO-201 (∼1500 BV) and much larger than D-201 (<250 BV). The exhausted HZO-201 can be in situ regenerated by using a binary NaOH-NaCl solution for cyclic runs, whether fed with the synthetic solution or real effluent. In general, HZO-201 is a promising alternative to Fe(III)-based adsorbents for trace phosphate removal from effluent particularly at acidic pH.

  10. Surface Coating of Oxide Powders: A New Synthesis Method to Process Biomedical Grade Nano-Composites

    Directory of Open Access Journals (Sweden)

    Paola Palmero

    2014-07-01

    Full Text Available Composite and nanocomposite ceramics have achieved special interest in recent years when used for biomedical applications. They have demonstrated, in some cases, increased performance, reliability, and stability in vivo, with respect to pure monolithic ceramics. Current research aims at developing new compositions and architectures to further increase their properties. However, the ability to tailor the microstructure requires the careful control of all steps of manufacturing, from the synthesis of composite nanopowders, to their processing and sintering. This review aims at deepening understanding of the critical issues associated with the manufacturing of nanocomposite ceramics, focusing on the key role of the synthesis methods to develop homogeneous and tailored microstructures. In this frame, the authors have developed an innovative method, named “surface-coating process”, in which matrix oxide powders are coated with inorganic precursors of the second phase. The method is illustrated into two case studies; the former, on Zirconia Toughened Alumina (ZTA materials for orthopedic applications, and the latter, on Zirconia-based composites for dental implants, discussing the advances and the potential of the method, which can become a valuable alternative to the current synthesis process already used at a clinical and industrial scale.

  11. Cobalt oxide magnetic nanoparticles-chitosan nanocomposite based electrochemical urea biosensor

    Science.gov (United States)

    Ali, A.; Israr-Qadir, M.; Wazir, Z.; Tufail, M.; Ibupoto, Z. H.; Jamil-Rana, S.; Atif, M.; Khan, S. A.; Willander, M.

    2015-04-01

    In this study, a potentiometric urea biosensor has been fabricated on glass filter paper through the immobilization of urease enzyme onto chitosan/cobalt oxide (CS/Co3O4) nanocomposite. A copper wire with diameter of 500 µm is attached with nanoparticles to extract the voltage output signal. The shape and dimensions of Co3O4 magnetic nanoparticles are investigated by scanning electron microscopy and the average diameter is approximately 80-100 nm. Structural quality of Co3O4 nanoparticles is confirmed from X-ray powder diffraction measurements, while the Raman spectroscopy has been used to understand the chemical bonding between different atoms. The magnetic measurement has confirmed that Co3O4 nanoparticles show ferromagnetic behavior, which could be attributed to the uncompensated surface spins and/or finite size effects. The ferromagnetic order of Co3O4 nanoparticles is raised with increasing the decomposition temperature. A physical adsorption method is adopted to immobilize the surface of CS/Co3O4 nanocomposite. Potentiometric sensitivity curve has been measured over the concentration range between 1 × 10-4 and 8 × 10-2 M of urea electrolyte solution revealing that the fabricated biosensor holds good sensing ability with a linear slope curve of 45 mV/decade. In addition, the presented biosensor shows good reusability, selectivity, reproducibility and resistance against interferers along with the stable output response of 12 s.

  12. Hyperbranched polysiloxane functionalized graphene oxide for dicyclopentadiene bisphenol dicyanate ester nanocomposites with high performance

    Directory of Open Access Journals (Sweden)

    H. X. Yan

    2014-06-01

    Full Text Available We report an efficient and novel method to functionalize graphene oxide (GO with hyperbranched polysiloxane and successfully compound them with dicyclopentadiene bisphenol dicyanate ester (DCPDCE to prepare nanocomposites. X-ray photoelectron spectroscopy (XPS and Fourier-transform infrared spectra (FT-IR were employed to examine the surface functionalization of GO. The effects of functionalized GO on the curing reaction, mechanical, dielectric and thermal properties of DCPDCE resin were investigated systematically. Results of DSC show that the addition of modified GO can facilitate the curing reaction of DCPDCE and decrease the curing temperature of DCPDCE. Compared with pure DCPDCE resin, the impact and flexural strengths of the nanocomposite materials are improved markedly with up to 66 and 50% increasing magnitude, respectively. Meanwhile, the modified GO/DCPDCE systems exhibit lower dielectric constant and loss than pure DCPDCE resin over the testing frequency from 10 to 60 MHz. In addition, the thermal stability and moisture resistance of modified GO/DCPDCE nanocomposties are also superior to that of pure DCPDCE resin.

  13. Development of a nanocomposite ultrafiltration membrane based on polyphenylsulfone blended with graphene oxide

    Science.gov (United States)

    Shukla, Arun Kumar; Alam, Javed; Alhoshan, Mansour; Dass, Lawrence Arockiasamy; Muthumareeswaran, M. R.

    2017-02-01

    In the present study, graphene oxide (GO) was incorporated as a nanoadditive into a polyphenylsulfone (PPSU) to develop a PPSU/GO nanocomposite membrane with enhanced antifouling properties. A series of membranes containing different concentrations (0.2, 0.5 and 1.0 wt.%) of GO were fabricated via the phase inversion method, using N-methyl pyrrolidone (NMP) as the solvent, deionized water as the non-solvent, and polyvinylpyrrolidone (PVP) as a pore forming agent. The prepared nanocomposite membranes were characterized using scanning electron microscopy (SEM) and atomic force microscopy (AFM), and were also characterized with respect to contact angle, zeta potential and porosity, mean pore radius, tortuosity and molecular weight cut-off (MWCO). Thermogravimetric analysis (TGA) and tensile testing were used to measure thermal and mechanical properties. The membrane performance was evaluated by volumetric flux and rejection of proteins, and antifouling properties. According to the results, the optimum addition of 0.5 wt% GO resulted in a membrane with an increased flux of 171 ± 3 Lm‑2h‑1 with a MWCO of ~40 kDa. In addition, the GO incorporation efficiently inhibited the interaction between proteins and the membrane surface, thereby improving the fouling resistance ability by approximately 58 ± 3%. Also, the resulting membranes showed a significant improvement in mechanical and thermal properties.

  14. Low-temperature processing of transparent conductive indium tin oxide nanocomposites using polyvinyl derivatives

    Energy Technology Data Exchange (ETDEWEB)

    Maksimenko, Ilja, E-mail: ilja.maksimenko@ww.uni-erlangen.de; Wellmann, Peter J.

    2011-12-01

    We report on the influence of additives on the electrical, optical, morphological and mechanical properties of transparent conductive indium tin oxide (In{sub 2}O{sub 3}:Sn; ITO) nanoparticle films by the use of polymers as matrix material. Key issues to fabricate layers suitable for use in electronic device applications are presented. Polyvinyl derivatives polyvinyl acetate, polyvinyl alcohol (PVA) and polyvinyl butyral were applied and their suitability to form transparent conductive ITO nanocomposite coatings at a maximum process temperature of 130 Degree-Sign C was investigated. A low-temperature treatment with UV-light has been developed to provide the possibility of curing ITO thin films deposited on substrates which do not withstand high process temperatures. Compared to best pure ITO layers (0.2 {Omega}{sup -1} cm{sup -1}), the ITO-PVA nanocomposite coatings show a conductance value of 4.1 {Omega}{sup -1} cm{sup -1} and 5.9 {Omega}{sup -1} cm{sup -1} after reducing in forming gas. Sheet resistance of ca. 1200 {Omega}/{open_square} with coexistent transmittance of 85% at 550 nm for a layer thickness of about 1.45 {mu}m was achieved. The conductance enhancement is a consequence of nanoparticulate ITO network densification due to the acting shrinkage forces caused by the polymer matrix during film drying and additionally UV-induced crosslinking of PVA.

  15. Chitosan-zinc oxide nanocomposite coatings for the prevention of marine biofouling.

    Science.gov (United States)

    Al-Naamani, Laila; Dobretsov, Sergey; Dutta, Joydeep; Burgess, J Grant

    2017-02-01

    Marine biofouling is a worldwide problem affecting maritime industries. Global concerns about the high toxicity of antifouling paints have highlighted the need to develop less toxic antifouling coatings. Chitosan is a natural polymer with antimicrobial, antifungal and antialgal properties that is obtained from partial deacetylation of crustacean waste. In the present study, nanocomposite chitosan-zinc oxide (chitosan-ZnO) nanoparticle hybrid coatings were developed and their antifouling activity was tested. Chitosan-ZnO nanoparticle coatings showed anti-diatom activity against Navicula sp. and antibacterial activity against the marine bacterium Pseudoalteromonas nigrifaciens. Additional antifouling properties of the coatings were investigated in a mesocosm study using tanks containing natural sea water under controlled laboratory conditions. Each week for four weeks, biofilm was removed and analysed by flow cytometry to estimate total bacterial densities on the coated substrates. Chitosan-ZnO hybrid coatings led to better inhibition of bacterial growth in comparison to chitosan coatings alone, as determined by flow cytometry. This study demonstrates the antifouling potential of chitosan-ZnO nanocomposite hybrid coatings, which can be used for the prevention of biofouling. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Zinc Oxide-Multi Walled Carbon Nanotubes Nanocomposites for Carbon Monoxide Gas Sensor Application.

    Science.gov (United States)

    Alharbi, Najlaa D; Ansari, M Shahnawaze; Salah, Numan; Khayyat, Suzan A; Khan, Zishan H

    2016-01-01

    Zinc oxide (ZnO)/multi walled carbon nanotubes (MWCNTs) composites based sensors with different ZnO concentrations were fabricated to improve carbon monoxide (CO) gas sensing properties in comparison to the sensors based on bare MWCNTs. To study the structure, morphology and elemental composition of the resultant products, X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM) and Energy dispersive X-ray spectroscopy (EDS) were carried out. It has been observed that as the concentration of ZnO is increased more and more ZnO nanoparticles in the form of nodes get attached to MWCNTs resulting the reduction in average diameter of MWCNTs. The typical response of ZnO/MWCNTs composites based gas sensors for different CO concentrations (40, 100, 140 and 200 ppm) was studied by using very advanced sensing setup attached to I-V measurement system. Different sensing parameters such as: resistive response, sensitivity and response time were estimated at room temperature for all the fabricated sensors. The results indicated that the sensor based on nanocomposite which has 30 mg ZnO dispersed on 20 mg MWCNTs showing highest sensitivity and fastest response. All the sensors showed response times ranging from 8 to 23 seconds. The sensing mechanism behind the sensors based on ZnO/MWCNTs nanocomposites for CO gas at room temperature is also discussed in the present report.

  17. Development of a nanocomposite ultrafiltration membrane based on polyphenylsulfone blended with graphene oxide

    Science.gov (United States)

    Shukla, Arun Kumar; Alam, Javed; Alhoshan, Mansour; Dass, Lawrence Arockiasamy; Muthumareeswaran, M. R.

    2017-01-01

    In the present study, graphene oxide (GO) was incorporated as a nanoadditive into a polyphenylsulfone (PPSU) to develop a PPSU/GO nanocomposite membrane with enhanced antifouling properties. A series of membranes containing different concentrations (0.2, 0.5 and 1.0 wt.%) of GO were fabricated via the phase inversion method, using N-methyl pyrrolidone (NMP) as the solvent, deionized water as the non-solvent, and polyvinylpyrrolidone (PVP) as a pore forming agent. The prepared nanocomposite membranes were characterized using scanning electron microscopy (SEM) and atomic force microscopy (AFM), and were also characterized with respect to contact angle, zeta potential and porosity, mean pore radius, tortuosity and molecular weight cut-off (MWCO). Thermogravimetric analysis (TGA) and tensile testing were used to measure thermal and mechanical properties. The membrane performance was evaluated by volumetric flux and rejection of proteins, and antifouling properties. According to the results, the optimum addition of 0.5 wt% GO resulted in a membrane with an increased flux of 171 ± 3 Lm−2h−1 with a MWCO of ~40 kDa. In addition, the GO incorporation efficiently inhibited the interaction between proteins and the membrane surface, thereby improving the fouling resistance ability by approximately 58 ± 3%. Also, the resulting membranes showed a significant improvement in mechanical and thermal properties. PMID:28155882

  18. Antimicrobial Bamboo Materials Functionalized with ZnO and Graphene Oxide Nanocomposites

    Directory of Open Access Journals (Sweden)

    Junyi Zhang

    2017-02-01

    Full Text Available Bamboo materials with improved antibacterial performance based on ZnO and graphene oxide (GO were fabricated by vacuum impregnation and hydrothermal strategies. The Zn2+ ions and GO nanosheets were firstly infiltrated into the bamboo structure, followed by dehydration and crystallization upon hydrothermal treatment, leading to the formation of ZnO/GO nanocomposites anchored in the bulk bamboo. The bamboo composites were characterized by several techniques including scanning electron microscopy (SEM, Fourier transform infrared spectra (FTIR, and X-ray diffraction (XRD, which confirmed the existence of GO and ZnO in the composites. Antibacterial performances of bamboo samples were evaluated by the bacteriostatic circle method. The introduction of ZnO/GO nanocomposites into bamboo yielded ZnO/GO/bamboo materials which exhibited significant antibacterial activity against Escherichia coli (E. coli, Gram-negative and Bacillus subtilis (B. subtilis, Gram-positive bacteria and high thermal stability. The antimicrobial bamboo would be expected to be a promising material for the application in the furniture, decoration, and construction industry.

  19. Functional porous carbon/nickel oxide nanocomposites as binder-free electrodes for supercapacitors.

    Science.gov (United States)

    Madhu, Rajesh; Veeramani, Vediyappan; Chen, Shen-Ming; Veerakumar, Pitchaimani; Liu, Shang-Bin

    2015-05-26

    High-surface-area, guava-leaf-derived, heteroatom-containing activated carbon (GHAC) materials were synthesized by means of a facile chemical activation method with KOH as activating agent and exploited as catalyst supports to disperse nickel oxide (NiO) nanocrystals (average size (2.0±0.1) nm) through a hydrothermal process. The textural and structural properties of these GHAC/NiO nanocomposites were characterized by various physicochemical techniques, namely, field-emission SEM, high-resolution TEM, elemental analysis, X-ray diffraction, X-ray photoelectron spectroscopy, thermogravimetric analysis, and Raman spectroscopy. The as-synthesized GHAC/NiO nanocomposites were employed as binder-free electrodes, which exhibited high specific capacitance (up to 461 F g(-1) at a current density of 2.3 A g(-1)) and remarkable cycling stability, which may be attributed to the unique properties of GHAC and excellent electrochemical activity of the highly dispersed NiO nanocrystals. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Optical properties of P3HT:tributylphosphine oxide-capped CdSe nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Benchaabane, A. [Faculte des Sciences d' Amiens, Laboratoire de Physique de la Matiere Condensee, Amiens (France); Universite Tunis El-Manar, Laboratoire de Materiaux avances et phenomenes quantiques, Faculte des Sciences de Tunis El Manar, Tunis (Tunisia); Universite Arabe des Sciences, Ecole Superieure d' Ingenieurs et des Etudes Technologiques, Tunis (Tunisia); Ben Hamed, Z.; Kouki, F.; Bouchriha, H. [Universite Tunis El-Manar, Laboratoire de Materiaux avances et phenomenes quantiques, Faculte des Sciences de Tunis El Manar, Tunis (Tunisia); Lahmar, A.; Zellama, K.; Zeinert, A. [Faculte des Sciences d' Amiens, Laboratoire de Physique de la Matiere Condensee, Amiens (France); Sanhoury, M.A. [Laboratoire de Chimie Organique Structurale, Synthese et Etudes Physicochimiques, Tunis (Tunisia)

    2016-08-15

    The optical properties of nanocomposite layers prepared by incorporation of tributylphosphine oxide (TBPO)-capped CdSe nanocrystals (NCs) in a P3HT polymer matrix are studied using different nanocrystal concentrations. Reflection spectra analyzed through Kim oscillator model lead to the determination of optical constants such as refractive index n, extinction coefficient k, dielectric permittivity ε and absorption coefficient α. Using the common Cauchy, Drude-Lorentz, Tauc and single-effective-oscillator theoretical models, we have determined the values of static refractive index n{sub s} and permittivity ε{sub s}, plasma frequency ω{sub p}, carrier density N, optical band gap E{sub g} and oscillator and dispersion energies E{sub 0} and E{sub d}, respectively. It is found that TBPO-capped CdSe NCs concentration affects the optoelectronic parameters of the nanocomposite thin films. Moreover, the disorder of this hybrid system is also studied by the determination of Urbach energy, which increases with TBPO-capped CdSe concentration. (orig.)

  1. Active sensing and damage detection using piezoelectric zinc oxide-based nanocomposites.

    Science.gov (United States)

    Meyers, Frederick N; Loh, Kenneth J; Dodds, John S; Baltazar, Arturo

    2013-05-10

    This study investigated the design and performance of piezoelectric nanocomposite-based interdigitated transducers (IDTs) for active sensing and damage detection. First, thin films that are highly piezoelectric and mechanically flexible were designed by embedding zinc oxide (ZnO) nanoparticles in a poly(vinylidene fluoride-trifluoroethylene) (PVDF-TrFE) piezo-polymer matrix. Second, the suspended nanoparticle solutions were then spin coated onto patterned comb electrodes to fabricate the IDTs. The films were then poled to align their electric domains and to increase their permanent piezoelectricity. Upon IDT fabrication, its sensing and actuation of Lamb waves on an aluminum pipe was validated. These results were also compared to data obtained from commercial Macro Fiber Composite IDT transducers. In the last phase of this work, damage detection was demonstrated by mounting these nanocomposite sensors and actuators (using a pitch-catch setup) onto an aluminum pipe and plate. Damage was simulated by tightening a band clamp around the pipe and by drilling holes in the plate. A damage index calculation was used to compare results corresponding to different levels of damage applied to the plate (i.e., different drilled hole depths), and good correlation was observed. Thus, ZnO/PVDF-TrFE transducers were shown to have the potential for use as piezoelectric transducers for structural health monitoring and damage detection.

  2. Smart nanocomposite hydrogels based on azo crosslinked graphene oxide for oral colon-specific drug delivery

    Science.gov (United States)

    Hou, Lin; Shi, Yuyang; Jiang, Guixiang; Liu, Wei; Han, Huili; Feng, Qianhua; Ren, Junxiao; Yuan, Yujie; Wang, Yongchao; Shi, Jinjin; Zhang, Zhenzhong

    2016-08-01

    A safe and efficient nanocomposite hydrogel for colon cancer drug delivery was synthesized using pH-sensitive and biocompatible graphene oxide (GO) containing azoaromatic crosslinks as well as poly (vinyl alcohol) (PVA) (GO-N=N-GO/PVA composite hydrogels). Curcumin (CUR), an anti-cancer drug, was encapsulated successfully into the hydrogel through a freezing and thawing process. Fourier transform infrared spectroscopy, scanning electron microscopy and Raman spectroscopy were performed to confirm the formation and morphological properties of the nanocomposite hydrogel. The hydrogels exhibited good swelling properties in a pH-sensitive manner. Drug release studies under conditions mimicking stomach to colon transit have shown that the drug was protected from being released completely into the physiological environment of the stomach and small intestine. In vivo imaging analysis, pharmacokinetics and a distribution of the gastrointestinal tract experiment were systematically studied and evaluated as colon-specific drug delivery systems. All the results demonstrated that GO-N=N-GO/PVA composite hydrogels could protect CUR well while passing through the stomach and small intestine to the proximal colon, and enhance the colon-targeting ability and residence time in the colon site. Therefore, CUR loaded GO-N=N-GO/PVA composite hydrogels might potentially provide a theoretical basis for the treatment of colon cancer with high efficiency and low toxicity.

  3. Design of Magnetic Gelatine/Silica Nanocomposites by Nanoemulsification: Encapsulation versus in Situ Growth of Iron Oxide Colloids

    Directory of Open Access Journals (Sweden)

    Joachim Allouche

    2014-07-01

    Full Text Available The design of magnetic nanoparticles by incorporation of iron oxide colloids within gelatine/silica hybrid nanoparticles has been performed for the first time through a nanoemulsion route using the encapsulation of pre-formed magnetite nanocrystals and the in situ precipitation of ferrous/ferric ions. The first method leads to bi-continuous hybrid nanocomposites containing a limited amount of well-dispersed magnetite colloids. In contrast, the second approach allows the formation of gelatine-silica core-shell nanostructures incorporating larger amounts of agglomerated iron oxide colloids. Both magnetic nanocomposites exhibit similar superparamagnetic behaviors. Whereas nanocomposites obtained via an in situ approach show a strong tendency to aggregate in solution, the encapsulation route allows further surface modification of the magnetic nanocomposites, leading to quaternary gold/iron oxide/silica/gelatine nanoparticles. Hence, such a first-time rational combination of nano-emulsion, nanocrystallization and sol-gel chemistry allows the elaboration of multi-component functional nanomaterials. This constitutes a step forward in the design of more complex bio-nanoplatforms.

  4. In situ polymerization and performance of alicyclic polyimide/graphene oxide nanocomposites derived from 6FAPB and CBDA

    Science.gov (United States)

    Lu, Yunhua; Hao, Jican; Xiao, Guoyong; Zhao, Hongbin; Hu, Zhizhi; Wang, Tonghua

    2017-02-01

    A series of alicyclic polyimide/graphene oxide(PI/GO) nanocomposites were successfully prepared by in situ polymerization of 1,4-bis(4-amino-2-trifluoromethylphenoxy)benzene(6FAPB) and 1,2,3,4-cyclobutanetetracarboxylic dianhydride(CBDA) as well as GO, followed by thermal imidization. The effect of GO on the thermal stability, optical properties, mechanical properties, water absorption and water surface contact angle of the PI-based nanocomposites was investigated. The optical properties of the pure alicyclic PI and corresponding PI-based nanocomposite films showed that the addition of GO reduced the transparency of PI films in the range of 200-800 nm obviously. With the increase of GO loading, the mechanical and thermal properties of alicyclic PI-based nanocomposites were enhanced. For the PI-1.0%GO nanocomposite films, the tensile strength was increased from 96 MPa (pure PI) to 109 MPa, and the Young's modulus was improved from 2.41 GPa (pure PI) to 3.83 GPa. The 10 wt% decomposition temperature for PI-1.0%GO nanocomposite films was increased from 464 (pure PI) to 481 °C, while the glass transition temperature (Tg) of PI/GO was slightly increased. In addition, the water surface contact angle of PI/GO enhanced from 71° to 82.5°, and the water uptake of PI/GO decreased from 2.58% to 1.48% with increasing the GO loadings. The uniform dispersion of GO in PI matrix was proved, and the pure PI and PI/GO nanocomposite films were amorphous.

  5. Multifunctional Fe{sub 3}O{sub 4}/graphene oxide nanocomposites for magnetic resonance imaging and drug delivery

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Guangshuo [School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024 (China); Chen, Guangyi [School of Automotive Engineering, Dalian University of Technology, Dalian 116024 (China); Wei, Zhiyong, E-mail: zywei@dlut.edu.cn [School of Automotive Engineering, Dalian University of Technology, Dalian 116024 (China); Dong, Xufeng [School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024 (China); Qi, Min, E-mail: minqi@dlut.edu.cn [School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024 (China)

    2013-09-16

    It is significant interest in developing novel multifunctional nanocarrier with complementary roles in recent years. Magnetic Fe{sub 3}O{sub 4}/graphene oxide (GO) nanocomposites with integrated characteristics of magnetic resonance imaging (MRI) and controlled drug delivery were prepared by an inverse co-precipitation method. The microstructure and physical properties of Fe{sub 3}O{sub 4}/GO nanocomposites were investigated by transmission electron microscope, wide-angle X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, thermogravimetric analyzer and superconducting quantum interference device magnetometer. The obtained nanocomposites exhibited superparamagnetic property with the saturation magnetization of 63.3 Am{sup 2} kg{sup −1} at room temperature. In vitro MRI experiments revealed that Fe{sub 3}O{sub 4}/GO nanocomposites possessed an excellent MRI enhancement effect. 5-Fluorouracil (5-FU) as an anti-tumor model drug was loaded onto the surface of Fe{sub 3}O{sub 4}/GO nanocomposites. The drug loading capacity of this nanocarrier was as high as 0.37 mg mg{sup −1} and the drug release behavior showed pH-dependence. The results suggested that the as-prepared Fe{sub 3}O{sub 4}/GO nanocomposites showed great potential as an effective multifunctional nanoplatform for MRI and controlled drug delivery. - Highlights: • Fe{sub 3}O{sub 4}/GO nanocomposites were prepared by inverse co-precipitation method. • Dual-functional characteristics with complimentary roles of MRI characteristic and drug delivery. • In vitro MRI: excellent MRI enhancement effect. • Drug delivery: high drug loading capacity and pH-sensitive controlled release.

  6. Synthesis and characterization of Zinc (II)-loaded Zeolite/Graphene oxide nanocomposite as a new drug carrier.

    Science.gov (United States)

    Khatamian, M; Divband, B; Farahmand-Zahed, F

    2016-09-01

    Current research has focused on the preparation of Zinc-clinoptilolite/Graphene Oxide (Zn-Clin/GO) hybrid nanostructure and investigating its biocompatibility for the first time. As prepared samples were characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM), Thermo gravimetric analysis (TGA) and Fourier transform infrared (FT-IR). In order to use it as a drug carrier two important factors were investigated: cytocompatibility of nanocomposites and their drug loading capacity. The results showed that the prepared nanocomposite is cytocompatible and its high loading capacity and slow release performance for Doxorubicin (DOX), as a cancer drug, proved that it can be used as a drug carrier. At last in-vitro toxicity of DOX loaded nanocomposite was compared with pure DOX.

  7. Effect of various amounts of graphene oxide on the degradation characteristics of the ZnSe/graphene nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Hsieh, S.H. [Department of Materials Science and Engineering, National Formosa University, 64, Wunhua Road, Huwei, Yunlin 632, Taiwan (China); Chen, W.J., E-mail: chenwjau@yuntech.edu.tw [Graduate School of Materials Science, National Yunlin University of Science and Technology, 123 University Road, Section 3, Douliou, Yunlin 64002, Taiwan (China); Yeh, T.H. [Graduate School of Materials Science, National Yunlin University of Science and Technology, 123 University Road, Section 3, Douliou, Yunlin 64002, Taiwan (China)

    2015-12-15

    Graphical abstract: When the ratio of the addition of GO to the amount of ZnSe–N{sub 2}H{sub 4} increases from 0.25 to 1, the degradation effect of GN–5 ml ZnSe on MB increases with increasing GO; the degradation efficiency of GN–ZnSe for MB increased from 35.4% to 99.6% after 6 h of visible light irradiation, which was the optimum degradation efficiency obtained in the present study. When the ratio of the addition of GO to the amount of ZnSe–N{sub 2}H{sub 4} increased from 1 to 2, the degradation efficiency of GN–5 ml ZnSe for MB decreased with the increasing addition of GO; the degradation efficiency of GN–5 ml ZnSe (2) only slightly decreased to 95.3% after 6 h of visible light irradiation. - Highlights: • The ZnSe/graphene nanocomposite was prepared using hydrothermal methods. • The ZnSe–N{sub 2}H{sub 4} reacted with different amount of GO and formed a ZnSe/graphene. • The degradation efficiency of the ZnSe/graphene depends on the amount of GO. • The photocatalytic activity was measured by the degradation of methylene blue. - Abstract: In this work, the graphene oxide (GO) sheets were synthesized by modified Hummers and Offeman's method. The GO was mixed with ZnSe that was prepared using various amounts of N{sub 2}H{sub 4} at a ratio of (0.25–2):1 to form precursors. The ZnSe/graphene nanocomposites were synthesized under hydrothermal conditions (180 °C; 12 h) from the previous precursor. Obtained ZnSe/graphene photocatalysts were characterized by X-ray diffraction analysis (XRD), Fourier transform infrared (FTIR) spectroscopy, UV–vis diffuse reflection spectroscopy, transmission electron microscope, scanning electron microscope, Raman spectra and X-ray photoelectron spectroscopy (XPS). Photocatalytic activity under visible light is evaluated in methylene blue (MB) dye degradation reaction in aqueous phase. The results show that the formation of ZnSe/graphene nanocomposite is depend on ratio of the addition of GO to the amount of

  8. Hydrothermal synthesis of graphene oxide/multiwalled carbon nanotube/Fe3O4 ternary nanocomposite for removal of Cu (II) and methylene blue

    Science.gov (United States)

    Long, Zhihang; Zhan, Yingqing; Li, Fei; Wan, Xinyi; He, Yi; Hou, Chunyan; Hu, Hai

    2017-09-01

    In this work, highly activated graphene oxide/multiwalled carbon nanotube/Fe3O4 ternary nanocomposite adsorbent was prepared from a simple hydrothermal route by using ferrous sulfate as precursor. For this purpose, the graphene oxide/multiwalled carbon nanotube architectures were formed through the π-π attractions between them, followed by attaching Fe3O4 nanoparticles onto their surface. The structure and composition of as-prepared ternary nanocomposite were characterized by XRD, FTIR, XPS, SEM, TEM, Raman, TGA, and BET. It was found that the resultant porous graphene oxide/multiwalled carbon nanotube/Fe3O4 ternary nanocomposite with large surface area could effectively prevent the π-π stacking interactions between graphene oxide nanosheets and greatly improve sorption sites on the surfaces. Thus, owing to the unique ternary nanocomposite architecture and synergistic effect among various components, as-prepared ternary nanocomposite exhibited high separation efficiency when they were used to remove the Cu (II) and methylene blue from aqueous solutions. Furthermore, the adsorption isotherms of ternary nanocomposite structures for Cu (II) and methylene blue removal fitted the Langmuir isotherm model. This work demonstrated that the graphene oxide/multiwalled carbon nanotube/Fe3O4 ternary nanocomposite was promising as an efficient adsorbent for heavy metal ions and organic dye removal from wastewater in low concentration.

  9. Synthesized chitosan/ iron oxide nanocomposite and shrimp shell in removal of nickel, cadmium and lead from aqueous solution

    Directory of Open Access Journals (Sweden)

    M. Keshvardoostchokami

    2017-09-01

    Full Text Available In this study, an easy synthesized method for preparation of chitosan/iron oxide nanocomposite as a bio-sorbent has been applied. Analytical techniques such as Fourier transform infrared spectroscopy, X-ray diffraction; Field emission scanning electron microscopy and transmission electron microscopy were utilized to survey of morphological structure and the functional groups characterization. The histogram of frequency of particle size confirmed that medium size of the synthesized nanoparticles was 50 nm. Beside the obtained nanocomposite, application of chitosan as the precursor and shrimp shell as natural chitin and a natural polymer were assessed as adsorbents for decontamination of Ni2+, Cd2+ and Pb2+ as examples of heavy metals from drinking water. Batch studies were performed for adsorption experiments by changing variables such as pH, contact time and adsorbent dose. Based on the experimental sorption capacities, 58, 202 and 12 mg of Ni, Cd and Pb per g of Chitosan-Fe2O3 nanocomposite as adsorbent respectively, confirm that combination of Fe2O3 nanoparticles with chitosan makes a more efficient adsorbent than chitosan and chitin. Adsorbents in uptake of the mentioned heavy metals are in the order of Chitosan-Fe2O3 nanocomposite > chitosan> chitin. In addition, the kinetics and isotherm investigations were surveyed. Moreover, it has been shown that the synthesized nanocomposite significantly reduces the amount of the mentioned ions from the real wastewater sample.

  10. Direct electrochemistry and electrocatalysis of glucose oxidase immobilized on reduced graphene oxide and silver nanoparticles nanocomposite modified electrode.

    Science.gov (United States)

    Palanisamy, Selvakumar; Karuppiah, Chelladurai; Chen, Shen-Ming

    2014-02-01

    The direct electrochemistry of glucose oxidase (GOx) was successfully realized on electrochemically reduced graphene oxide and silver nanoparticles (RGO/Ag) nanocomposite modified electrode. The fabricated nanocomposite was characterized by field emission scanning electron microscope and energy dispersive spectroscopy. The GOx immobilized nanocomposite modified electrode showed a pair of well-defined redox peaks with a formal potential (E°) of -0.422 V, indicating that the bioactivity of GOx was retained. The heterogeneous electron transfer rate constant (Ks) of GOx at the nanocomposite was calculated to be 5.27 s(-1), revealing a fast direct electron transfer of GOx. The GOx immobilized RGO/Ag nanocomposite electrode exhibited a good electrocatalytic activity toward glucose over a linear concentration range from 0.5 to 12.5 mM with a detection limit of 0.16 mM. Besides, the fabricated biosensor showed an acceptable sensitivity and selectivity for glucose. Copyright © 2013 Elsevier B.V. All rights reserved.

  11. Effects of graphene oxide concentration on optical properties of ZnO/RGO nanocomposites and their application to photocurrent generation

    Energy Technology Data Exchange (ETDEWEB)

    Azarang, Majid, E-mail: azarangmajid@gmail.com, E-mail: azarang@phys.usb.ac.ir [Low Dimensional Materials Research Center, Department of Physics, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia); Department of Physics, University of Sistan and Baluchestan, 98135-674 Zahedan (Iran, Islamic Republic of); Shuhaimi, Ahmad; Sookhakian, M. [Low Dimensional Materials Research Center, Department of Physics, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia); Yousefi, Ramin, E-mail: Yousefi.ramin@gmail.com, E-mail: raminyousefi@iaumis.ac.ir [Department of Physics, Masjed-Soleiman Branch, Islamic Azad University (I.A.U), Masjed-Soleiman (Iran, Islamic Republic of)

    2014-08-28

    The effects of different concentrations of graphene oxide (GO) on the structure and optical properties of ZnO nanoparticles (NPs) were investigated. The nanocomposites were synthesized via the sol-gel method in a gelatin medium. X-ray diffraction patterns (XRD) and Fourier transform infrared spectroscopy indicated that the GO sheets were reduced and changed to reduced GO (RGO) during the calcination of the nanocomposites at 400 °C. In addition, the XRD patterns of the NPs indicated a hexagonal (wurtzite) structure for all the products. Microscopic studies showed that the NPs were decorated and dispersed on the RGO sheets very well. However, these studies revealed that the RGO concentration had an effect on the crystal growth process for the ZnO NPs. Furthermore, these studies showed that the NPs could be grown with a single crystal quality in an optimum RGO concentration. According to the XRD results that were obtained from pure ZnO NPs, the calcinations temperature was decreased by the RGO. UV–vis and room temperature photoluminescence studies showed that the optical properties of the ZnO/RGO nanocomposite were affected by the RGO concentration. Finally, the obtained ZnO/RGO nanocomposite was used to generate a photocurrent. Observations showed that the photocurrent intensity of the nanocomposite was significantly increased by increasing the RGO, with an optimum RGO concentration.

  12. Magnetic graphene oxide-polystyrene and magnetic activated carbon-polystyrene nanocomposites as sorbents for bisphenol A.

    Science.gov (United States)

    Rekos, Kyriazis; Kampouraki, Zoi Christina; Samanidou, Victoria; Deliyanni, Eleni

    2016-04-01

    Magnetic graphene oxide-polystyrene and magnetic activated carbon-polystyrene nanocomposites as sorbents for bisphenol A. Kyriazis Rekos1, Zoi Christina Kampouraki1, Victoria Samanidou2, Eleni Deliyanni1 1 Laboratory of General and Inorganic Chemical Technology, Department of Chemistry, Aristotle University of Thessaloniki, GR-541 24 Thessaloniki, Greece 2 Laboratory of Analytical Chemistry, Department of Chemistry, Aristotle University of Thessaloniki, GR-541 24 Thessaloniki, Greece The aim of this work was to prepare and characterize novel composites of magnetic activated carbon or magnetic graphene oxide with polystyrene (GO/PSm), through one step simple and effective route. Μagnetite nanoparticles, prepared in the laboratory, were dispersed in the presence of activated carbon (C) or graphene oxide (GO) in a polystyrene (PS) solution in dimethylformamide, at elevated temperature, for the fabrication of the magnetite-Carbon-PS (C-PSm) and magnetite- Graphene Oxide-PS (GO-PSm) hybrid-nanoparticles. For comparison, C-PS and GO-PS composites were also prepared in the same route. The nanocomposites were tested for their sorption ability for an endocrine disruptor, bisphenol A. The effect of solution pH, initial concentration, contact time and temperature were examined. The magnetic graphite oxide-polystyrene presented higher adsorption capacity (100 mg/g) than the non magnetic composites (70 mg/g), as well as than initial graphite oxide (20 mg/g). FTIR, XRD, BET, TGA, VSM and SEM were performed in order to investigate the role of the PS on the better adsorption performance of the mGO-PS nanocomposites. The characterization with these techniques revealed the possible interactions of the surface functional groups of activated carbon and/or graphite oxide with polystyrene that resulted in the better performance of the magnetic nanocomposites for bisphenol A adsorption.

  13. Pd-Cu/poly(o-Anisidine) nanocomposite as an efficient catalyst for formaldehyde oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Hosseini, Sayed Reza, E-mail: r.hosseini@umz.ac.ir [Nanochemistry Research Laboratory, Faculty of Chemistry, University of Mazandaran, 47416-95447 Babolsar (Iran, Islamic Republic of); Raoof, Jahan-Bakhsh [Department of Analytical Chemistry, Faculty of Chemistry, University of Mazandaran, 47416-95447 Babolsar (Iran, Islamic Republic of); Ghasemi, Shahram; Gholami, Zahra [Nanochemistry Research Laboratory, Faculty of Chemistry, University of Mazandaran, 47416-95447 Babolsar (Iran, Islamic Republic of)

    2016-08-15

    Highlights: • o-Anisidine monomer was electro-polymerized at the pCPE surface in acid medium. • Palladium/copper NPs were prepared by galvanic replacement method at the POA/pCPE. • Pd-Cu NPs showed excellent electrocatalytic activity towards formaldehyde oxidation. • The bimetallic Pd-Cu NPs/POA nanocomposite showed satisfactory long-term stability. - Abstract: In this work, for the first time, the electrocatalytic oxidation of formaldehyde in 0.5 M sulfuric acid solution at spherical bimetallic palladium-copper nanoparticles (Pd-Cu NPs) deposited on the poly (o-Anisidine) film modified electrochemically pretreated carbon paste electrode (POA/pCPE) has been investigated. Highly porous POA film prepared by electropolymerization onto the pCPE was used as a potent support for deposition of the Pd-Cu NPs. The Pd-Cu NPs were prepared through spontaneous and irreversible reaction via galvanic replacement between Pd{sup II} ions and the Cu{sup 0} particles. The prepared Pd-Cu NPs were characterized by scanning electron microscopy, energy dispersive spectroscopy and electrochemical methods. The obtained results showed that the utilization of Cu nanoparticles and pretreatment technique enhances the electrocatalytic activity of the modified electrode towards formaldehyde oxidation. The influence of several parameters on formaldehyde oxidation as well as stability of the Pd-Cu/POA/pCPE has been investigated.

  14. Mechanochemical production of nanocomposites of metal/oxide and intermetallic/oxide systems

    Energy Technology Data Exchange (ETDEWEB)

    Grigoryeva, T F; Barinova, A P; Ancharov, A I; Vorsina, I A; Lyakhov, N Z [Institute of Solid State Chemistry and Mechanochemistry, SB RAS, Novosibirsk (Russian Federation); Novakova, A A; Kiseleva, T Yu [M.V. Lomonosov Moscow State University, Moscow (Russian Federation); Talako, T L [Institute of Powder Metallurgy, NAS of Belarus, Minsk (Belarus); Becker, K D; Sepelak, V [Institute of Physical and Theoretical Chemistry, Braunschweig University of Technology, Braunschweig (Germany); Tsybulya, S V; Bulavchenko, O A, E-mail: grig@solid.nsc.r [G.K. Boreskov Institute of Catalysts, SB RAS, Novosibirsk (Russian Federation)

    2009-01-01

    Addition of nanosized intermetallic or metallic phases into corundum considerably raises mechanical behavior of the material. In this work, the nanocomposites of alpha-Al{sup 2}O{sup 3}/intermetallic and alpha-Al{sup 2}O{sup 3}/metal systems were obtained by mechanochemical reduction of alpha-Fe{sup 2}O{sup 3} by Al (and by solid solution of Al in Fe). The mechanochemical reduction process of hematite by various amount of metal-reducer was studied by IR and Moessbauer spectroscopies, and by X-ray synchrotron radiation diffraction technique.

  15. Photocatalytical Antibacterial Activity of Mixed-Phase TiO2 Nanocomposite Thin Films against Aggregatibacter actinomycetemcomitans.

    Science.gov (United States)

    Yeniyol, Sinem; Mutlu, Ilven; He, Zhiming; Yüksel, Behiye; Boylan, Robert Joseph; Ürgen, Mustafa; Karabuda, Zihni Cüneyt; Basegmez, Cansu; Ricci, John Lawrence

    2015-01-01

    Mixed-phase TiO2 nanocomposite thin films consisting of anatase and rutile prepared on commercially pure Ti sheets via the electrochemical anodization and annealing treatments were investigated in terms of their photocatalytic activity for antibacterial use around dental implants. The resulting films were characterized by scanning electron microscopy (SEM), and X-ray diffraction (XRD). The topology was assessed by White Light Optical Profiling (WLOP) in the Vertical Scanning Interferometer (VSI) mode. Representative height descriptive parameters of roughness R a and R z were calculated. The photocatalytic activity of the resulting TiO2 films was evaluated by the photodegradation of Rhodamine B (RhB) dye solution. The antibacterial ability of the photocatalyst was examined by Aggregatibacter actinomycetemcomitans suspensions in a colony-forming assay. XRD showed that anatase/rutile mixed-phase TiO2 thin films were predominantly in anatase and rutile that were 54.6 wt% and 41.9 wt%, respectively. Craters (2-5 µm) and protruding hills (10-50 µm) on Ti substrates were produced after electrochemical anodization with higher R a and R z surface roughness values. Anatase/rutile mixed-phase TiO2 thin films showed 26% photocatalytic decolorization toward RhB dye solution. The number of colonizing bacteria on anatase/rutile mixed-phase TiO2 thin films was decreased significantly in vitro. The photocatalyst was effective against A. actinomycetemcomitans colonization.

  16. Photocatalytical Antibacterial Activity of Mixed-Phase TiO2 Nanocomposite Thin Films against Aggregatibacter actinomycetemcomitans

    Directory of Open Access Journals (Sweden)

    Sinem Yeniyol

    2015-01-01

    Full Text Available Mixed-phase TiO2 nanocomposite thin films consisting of anatase and rutile prepared on commercially pure Ti sheets via the electrochemical anodization and annealing treatments were investigated in terms of their photocatalytic activity for antibacterial use around dental implants. The resulting films were characterized by scanning electron microscopy (SEM, and X-ray diffraction (XRD. The topology was assessed by White Light Optical Profiling (WLOP in the Vertical Scanning Interferometer (VSI mode. Representative height descriptive parameters of roughness Ra and Rz were calculated. The photocatalytic activity of the resulting TiO2 films was evaluated by the photodegradation of Rhodamine B (RhB dye solution. The antibacterial ability of the photocatalyst was examined by  Aggregatibacter actinomycetemcomitans suspensions in a colony-forming assay. XRD showed that anatase/rutile mixed-phase TiO2 thin films were predominantly in anatase and rutile that were 54.6 wt% and 41.9 wt%, respectively. Craters (2–5 µm and protruding hills (10–50 µm on Ti substrates were produced after electrochemical anodization with higher Ra and Rz surface roughness values. Anatase/rutile mixed-phase TiO2 thin films showed 26% photocatalytic decolorization toward RhB dye solution. The number of colonizing bacteria on anatase/rutile mixed-phase TiO2 thin films was decreased significantly in vitro. The photocatalyst was effective against A. actinomycetemcomitans colonization.

  17. Selective oxidation of isobutane on V–Mo–O mixed oxide catalysts

    Directory of Open Access Journals (Sweden)

    GHEORGHITA MITRAN

    2008-01-01

    Full Text Available Four V–Mo–O mixed metal oxides were prepared, characterized and tested for the selective oxidation of isobutane in the temperature range 350–550 °C, at atmospheric pressure. Isobutane was mainly oxidized to iso-butene and carbon oxides. The systems with low vanadium contents showed low activities but high isobutene selectivities, while the systems with high vanadium contents showed high activities with high carbon oxides selectivities. The effects of temperature, contact time and the molar ratio iso-butane to oxygen on the conversion of isobutane and the selectivity of the oxidation were studied.

  18. Electrophoretic deposition and electrochemical behavior of novel graphene oxide-hyaluronic acid-hydroxyapatite nanocomposite coatings

    Science.gov (United States)

    Li, Ming; Liu, Qian; Jia, Zhaojun; Xu, Xuchen; Shi, Yuying; Cheng, Yan; Zheng, Yufeng; Xi, Tingfei; Wei, Shicheng

    2013-11-01

    Novel ternary graphene oxide-hyaluronic acid-hydroxyapatite (GO-HY-HA) nanocomposite coatings were prepared on Ti substrate using anodic electrophoretic deposition (EPD). Hyaluronic acid was employed as charging additive and dispersion agent during EPD. The kinetics and mechanism of the deposition, and the microstructure of the coated samples were investigated using scanning electron microscopy, X-ray diffraction, Raman spectrum, thermo-gravimetric analysis, and microscopic Fourier transform infrared analysis. The results showed that the addition of GO sheets into the HY-HA suspensions could increase the deposition rate and inhibit cracks creation and propagation in the coatings. The corrosion resistant of the resulting samples were evaluated using potentiodynamic polarization method in simulated body fluid, and the GO-HY-HA coatings could effectively improve the anti-corrosion property of the Ti substrate.

  19. Evidence of interfacial charge trapping mechanism in polyaniline/reduced graphene oxide nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Islam, Rakibul; Brun, Jean-François; Roussel, Frederick, E-mail: frederick.roussel@univ-lille1.fr [University of Lille, Sciences & Technologies, Unité Matériaux et Transformations (UMET), UMR CNRS 8207, U.F.R. de Physique, P5, 59655 Villeneuve d' Ascq Cedex (France); COMUE Lille Nord de France, BP 50458-59658 Villeneuve d' Ascq Cedex (France); Papathanassiou, Anthony N. [Physics Department, Solid State Physics Section, University of Athens, Panepistimiopolis, GR15784 Zografos, Athens (Greece); Chan Yu King, Roch [Science Division, University of Science and Arts of Oklahoma, Chickasha, Oklahoma 73018 (United States)

    2015-08-03

    Relaxation mechanisms in polyaniline (PANI)/Reduced Graphene Oxide (RGO) nanocomposites are investigated using broad band dielectric spectroscopy. The multilayered nanostructural features of the composites and the intimate interactions between PANI and RGO are evidenced by field emission scanning electron microscopy, transmission electron microscopy, and Raman spectroscopy. Increasing the RGO fraction in the composites results in a relaxation process observed at a frequency of ca. 5 kHz. This mechanism is associated with an electrical charge trapping phenomenon occurring at the PANI/RGO interfaces. The dielectric relaxation processes are interpreted according to the Sillars approach and the results are consistent with the presence of conducting prolate spheroids (RGO) embedded into a polymeric matrix (PANI). Dielectric permittivity data are analyzed within the framework of the Kohlrausch-William-Watts model, evidencing a Debye-like relaxation process.

  20. Mechanochemical Synthesis of TiO2 Nanocomposites as Photocatalysts for Benzyl Alcohol Photo-Oxidation

    Directory of Open Access Journals (Sweden)

    Weiyi Ouyang

    2016-05-01

    Full Text Available TiO2 (anatase phase has excellent photocatalytic performance and different methods have been reported to overcome its main limitation of high band gap energy. In this work, TiO2-magnetically-separable nanocomposites (MAGSNC photocatalysts with different TiO2 loading were synthesized using a simple one-pot mechanochemical method. Photocatalysts were characterized by a number of techniques and their photocatalytic activity was tested in the selective oxidation of benzyl alcohol to benzaldehyde. Extension of light absorption into the visible region was achieved upon titania incorporation. Results indicated that the photocatalytic activity increased with TiO2 loading on the catalysts, with moderate conversion (20% at high benzaldehyde selectivity (84% achieved for 5% TiO2-MAGSNC. These findings pointed out a potential strategy for the valorization of lignocellulosic-based biomass under visible light irradiation using designer photocatalytic nanomaterials.

  1. Mechanochemical Synthesis of TiO2 Nanocomposites as Photocatalysts for Benzyl Alcohol Photo-Oxidation

    Science.gov (United States)

    Ouyang, Weiyi; Kuna, Ewelina; Yepez, Alfonso; Balu, Alina M.; Romero, Antonio A.; Colmenares, Juan Carlos; Luque, Rafael

    2016-01-01

    TiO2 (anatase phase) has excellent photocatalytic performance and different methods have been reported to overcome its main limitation of high band gap energy. In this work, TiO2-magnetically-separable nanocomposites (MAGSNC) photocatalysts with different TiO2 loading were synthesized using a simple one-pot mechanochemical method. Photocatalysts were characterized by a number of techniques and their photocatalytic activity was tested in the selective oxidation of benzyl alcohol to benzaldehyde. Extension of light absorption into the visible region was achieved upon titania incorporation. Results indicated that the photocatalytic activity increased with TiO2 loading on the catalysts, with moderate conversion (20%) at high benzaldehyde selectivity (84%) achieved for 5% TiO2-MAGSNC. These findings pointed out a potential strategy for the valorization of lignocellulosic-based biomass under visible light irradiation using designer photocatalytic nanomaterials. PMID:28335221

  2. Preparation and corrosion resistance of a nanocomposite plasma electrolytic oxidation coating on Mg-1%Ca alloy formed in aluminate electrolyte containing titania nano-additives

    DEFF Research Database (Denmark)

    Daroonparvar, Mohammadreza; Yajid, M. A. M.; Yusof, N. M.

    2016-01-01

    Titania nanoparticles were utilized as suspension in alkaline aluminate electrolyte to form nanocomposite coatings on magnesium alloy containing 1 wt% calcium by plasma electrolytic oxidation process. Microhardness, wettability, potentiodynamic polarization, wettability, electrochemical impedance...

  3. Tuning the mechanical properties of graphene oxide paper and its associated polymer nanocomposites by controlling cooperative intersheet hydrogen bonding.

    Science.gov (United States)

    Compton, Owen C; Cranford, Steven W; Putz, Karl W; An, Zhi; Brinson, L Catherine; Buehler, Markus J; Nguyen, SonBinh T

    2012-03-27

    The mechanical properties of pristine graphene oxide paper and paper-like films of polyvinyl alcohol (PVA)-graphene oxide nanocomposite are investigated in a joint experimental-theoretical and computational study. In combination, these studies reveal a delicate relationship between the stiffness of these papers and the water content in their lamellar structures. ReaxFF-based molecular dynamics (MD) simulations elucidate the role of water molecules in modifying the mechanical properties of both pristine and nanocomposite graphene oxide papers, as bridge-forming water molecules between adjacent layers in the paper structure enhance stress transfer by means of a cooperative hydrogen-bonding network. For graphene oxide paper at an optimal concentration of ~5 wt % water, the degree of cooperative hydrogen bonding within the network comprising adjacent nanosheets and water molecules was found to optimally enhance the modulus of the paper without saturating the gallery space. Introducing PVA chains into the gallery space further enhances the cooperativity of this hydrogen-bonding network, in a manner similar to that found in natural biomaterials, resulting in increased stiffness of the composite. No optimal water concentration could be found for the PVA-graphene oxide nanocomposite papers, as dehydration of these structures continually enhances stiffness until a final water content of ~7 wt % (additional water cannot be removed from the system even after 12 h of annealing).

  4. Immunosensor based on nanocomposite of nanostructured zirconium oxide and gelatin-A.

    Science.gov (United States)

    Bagbi, Yana; Sharma, Anshu; Bohidar, H B; Solanki, Pratima R

    2016-01-01

    We have reported the studies related to the fabrication of a nanocomposite, comprising of sol-gel derived inorganic zirconium oxide nanoparticles (ZrO2 NPs) and organic biopolymer gelatin-A (GA), deposited on indium-tin-oxide (ITO) coated glass substrate by drop casting method. The GA-ZrO2/ITO electrode was used for immobilization of monoclonal antibodies (Ab) specific to antigen Vibrio cholerae (Vc) followed by bovine serum albumin (BSA) for antigen Vc detection using electrochemical techniques. The structural and morphological behaviour of these ZrO2 NPs, GA-ZrO2/ITO electrode and BSA/Ab/GA-ZrO2/ITO immunosensor was characterized by scanning electron microscopy and Fourier transform infrared spectroscopy techniques. The transmission electron microscopy study exhibited a spherical shape ZrO2 NPs. The average crystalline size of ZrO2 NPs was obtained as 10.3 ± 1 nm from X-ray diffraction measurement and 72 nm hydrodynamic radius measured by dynamic light scattering. GA-ZrO2 nanocomposite provides a porous structure which assists to higher loading of Ab on the matrix surface that improved the biosensing properties. The electrochemical response studies of the fabricated BSA/Ab/GA-ZrO2/ITO immunosensor exhibited good linearity in the range of 50-400 ng mL(-1), low limit of detection of 0.74 ng/mL, sensitivity as 0.03 Ω ng(-1)mL(-1)cm(-2) and reproducibility more than 10 times.

  5. Photochemical oxidation: A solution for the mixed waste dilemma

    Energy Technology Data Exchange (ETDEWEB)

    Prellberg, J.W.; Thornton, L.M.; Cheuvront, D.A. [Vulcan Peroxidation Systems, Inc., Tucson, AZ (United States)] [and others

    1995-12-31

    Numerous technologies are available to remove organic contamination from water or wastewater. A variety of techniques also exist that are used to neutralize radioactive waste. However, few technologies can satisfactorily address the treatment of mixed organic/radioactive waste without creating unacceptable secondary waste products or resulting in extremely high treatment costs. An innovative solution to the mixed waste problem is on-site photochemical oxidation. Liquid-phase photochemical oxidation has a long- standing history of successful application to the destruction of organic compounds. By using photochemical oxidation, the organic contaminants are destroyed on-site leaving the water, with radionuclides, that can be reused or disposed of as appropriate. This technology offers advantages that include zero air emissions, no solid or liquid waste formation, and relatively low treatment cost. Discussion of the photochemical process will be described, and several case histories from recent design testing, including cost analyses for the resulting full-scale installations, will be presented as examples.

  6. A metallic metal oxide (Ti5O9)-metal oxide (TiO2) nanocomposite as the heterojunction to enhance visible-light photocatalytic activity.

    Science.gov (United States)

    Li, L H; Deng, Z X; Xiao, J X; Yang, G W

    2015-01-26

    Coupling titanium dioxide (TiO2) with other semiconductors is a popular method to extend the optical response range of TiO2 and improve its photon quantum efficiency, as coupled semiconductors can increase the separation rate of photoinduced charge carriers in photocatalysts. Differing from normal semiconductors, metallic oxides have no energy gap separating occupied and unoccupied levels, but they can excite electrons between bands to create a high carrier mobility to facilitate kinetic charge separation. Here, we propose the first metallic metal oxide-metal oxide (Ti5O9-TiO2) nanocomposite as a heterojunction for enhancing the visible-light photocatalytic activity of TiO2 nanoparticles and we demonstrate that this hybridized TiO2-Ti5O9 nanostructure possesses an excellent visible-light photocatalytic performance in the process of photodegrading dyes. The TiO2-Ti5O9 nanocomposites are synthesized in one step using laser ablation in liquid under ambient conditions. The as-synthesized nanocomposites show strong visible-light absorption in the range of 300-800 nm and high visible-light photocatalytic activity in the oxidation of rhodamine B. They also exhibit excellent cycling stability in the photodegrading process. A working mechanism for the metallic metal oxide-metal oxide nanocomposite in the visible-light photocatalytic process is proposed based on first-principle calculations of Ti5O9. This study suggests that metallic metal oxides can be regarded as partners for metal oxide photocatalysts in the construction of heterojunctions to improve photocatalytic activity.

  7. Heterogeneous Partial (ammOxidation and Oxidative Dehydrogenation Catalysis on Mixed Metal Oxides

    Directory of Open Access Journals (Sweden)

    Jacques C. Védrine

    2016-01-01

    Full Text Available This paper presents an overview of heterogeneous partial (ammoxidation and oxidative dehydrogenation (ODH of hydrocarbons. The review has been voluntarily restricted to metal oxide-type catalysts, as the partial oxidation field is very broad and the number of catalysts is quite high. The main factors of solid catalysts for such reactions, designated by Grasselli as the “seven pillars”, and playing a determining role in catalytic properties, are considered to be, namely: isolation of active sites (known to be composed of ensembles of atoms, Me–O bond strength, crystalline structure, redox features, phase cooperation, multi-functionality and the nature of the surface oxygen species. Other important features and physical and chemical properties of solid catalysts, more or less related to the seven pillars, are also emphasized, including reaction sensitivity to metal oxide structure, epitaxial contact between an active phase and a second phase or its support, synergy effect between several phases, acid-base aspects, electron transfer ability, catalyst preparation and activation and reaction atmospheres, etc. Some examples are presented to illustrate the importance of these key factors. They include light alkanes (C1–C4 oxidation, ethane oxidation to ethylene and acetic acid on MoVTe(SbNb-O and Nb doped NiO, propene oxidation to acrolein on BiMoCoFe-O systems, propane (ammoxidation to (acrylonitrile acrylic acid on MoVTe(SbNb-O mixed oxides, butane oxidation to maleic anhydride on VPO: (VO2P2O7-based catalyst, and isobutyric acid ODH to methacrylic acid on Fe hydroxyl phosphates. It is shown that active sites are composed of ensembles of atoms whose size and chemical composition depend on the reactants to be transformed (their chemical and size features and the reaction mechanism, often of Mars and van Krevelen type. An important aspect is the fact that surface composition and surface crystalline structure vary with reaction on stream until

  8. Thermo-mechanical properties of mixed-matrix membranes encompassing zeolitic imidazolate framework-90 and polyvinylidine difluoride: ZIF-90/PVDF nanocomposites

    Science.gov (United States)

    Flyagina, Irina S.; Mahdi, E. M.; Titov, Kirill; Tan, Jin-Chong

    2017-08-01

    Mixed-matrix membranes are contemporary nanocomposite materials with many potential applications, from liquid and gas separations to chemical sensors and biomedicine. We report fabrication of a metal-organic framework (MOF)-based nanocomposite, combining polyvinylidene difluoride (PVDF) polymer as the matrix and ZIF-90 nanocrystals of up to 30 wt. % filler content. The focus is to establish the processing—microstructure—mechanical property relationships. We reveal the importance for quantifying salient effects of the filler contents: (i) tensile strength degrades beyond 10 wt. % and (ii) mechanical toughness declines due to membrane embrittlement. These are vital mechanical aspects but widely overlooked in the emergent field of MOF membranes and composites.

  9. Reduced graphene oxide/PAMAM-silver nanoparticles nanocomposite modified electrode for direct electrochemistry of glucose oxidase and glucose sensing.

    Science.gov (United States)

    Luo, Zhimin; Yuwen, Lihui; Han, Yujie; Tian, Jing; Zhu, Xingrong; Weng, Lixing; Wang, Lianhui

    2012-01-01

    Reduced graphene oxide/PAMAM-silver nanoparticles nanocomposite (RGO-PAMAM-Ag) was synthesized by self-assembly of carboxyl-terminated PAMAM dendrimer (PAMAM-G3.5) on graphene oxide (GO) as growing template, and in-situ reduction of both AgNO(3) and GO under microwave irradiation. The RGO-PAMAM-Ag nanocomposite was used as a novel immobilization matrix for glucose oxidase (GOD) and exhibited excellent direct electron transfer properties for GOD with the rate constant (K(s)) of 8.59 s(-1). The fabricated glucose biosensor based on GOD electrode modified with RGO-PAMAM-Ag nanocomposite displayed satisfactory analytical performance including high sensitivity (75.72 μA mM(-1) cm(-2)), low detection limit (4.5 μM), an acceptable linear range from 0.032 mM to 1.89 mM, and also preventing the interference of some interfering species usually coexisting with glucose in human blood at the work potential of -0.25 V. These results indicated that RGO-PAMAM-Ag nanocomposite is a promising candidate material for high-performance glucose biosensors.

  10. Synthesis and characterization of Zinc (II)-loaded Zeolite/Graphene oxide nanocomposite as a new drug carrier

    Energy Technology Data Exchange (ETDEWEB)

    Khatamian, M. [Inorganic Chemistry Department, Faculty of Chemistry, University of Tabriz, C.P. 51664 Tabriz (Iran, Islamic Republic of); Divband, B., E-mail: baharakdivband@yahoo.com [Research Center for Pharmaceutical Nanotechnology, Tabriz University of Medical Sciences, Tabriz (Iran, Islamic Republic of); Inorganic Chemistry Department, Faculty of Chemistry, University of Tabriz, C.P. 51664 Tabriz (Iran, Islamic Republic of); Farahmand-zahed, F. [Inorganic Chemistry Department, Faculty of Chemistry, University of Tabriz, C.P. 51664 Tabriz (Iran, Islamic Republic of)

    2016-09-01

    Current research has focused on the preparation of Zinc-clinoptilolite/Graphene Oxide (Zn-Clin/GO) hybrid nanostructure and investigating its biocompatibility for the first time. As prepared samples were characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM), Thermo gravimetric analysis (TGA) and Fourier transform infrared (FT-IR). In order to use it as a drug carrier two important factors were investigated: cytocompatibility of nanocomposites and their drug loading capacity. The results showed that the prepared nanocomposite is cytocompatible and its high loading capacity and slow release performance for Doxorubicin (DOX), as a cancer drug, proved that it can be used as a drug carrier. At last in-vitro toxicity of DOX loaded nanocomposite was compared with pure DOX. - Graphical abstract: Biocompatible Zn-clinoptilolite/Graphene oxide hybrid nanostructure as in vitro drug delivery systems (DDS) was able to store and release substantial amounts of doxorubicin to the lung cancer cell lines. Display Omitted - Highlights: • Zn-Clin/GO nanocomposite as a new in vitro drug carrier with high loading capacity is synthesized. • Two synthesis methods (Microwave assisted hydrothermal method and Reflux method) are used. • All of the carriers (Zn-Clin, Zn-Clin/GO, GO) showed high biocompatibility.

  11. Radiation synthesis of CdS/reduced graphene oxide nanocomposites for visible-light-driven photocatalytic degradation of organic contaminant

    Science.gov (United States)

    Fu, Xiaoyang; Zhang, Youwei; Cao, Pengfei; Ma, Huiling; Liu, Pinggui; He, Lihua; Peng, Jing; Li, Jiuqiang; Zhai, Maolin

    2016-06-01

    CdS/reduced graphene oxide (CdS/RGO) nanocomposites were successfully synthesized via a one-step gamma-ray radiation-induced reduction method. The composition and structure of the prepared nanocomposites were characterized by thermal gravimetric analysis, micro FTIR spectroscopy, UV-vis spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy and transmission electron microscopy. It was found that increasing dose could improve the degree of reduction of graphite oxide (GO), and the feed ratio of GO to CdCl2·2.5H2O significantly influenced the size and dispersion of the CdS nanoparticles. The nanocomposites prepared under dose of 300 kGy and the feed ratio of GO to CdCl2·2.5H2O 1.0 wt% exhibited high visible-light photocatalytic performance for the degradation of Rhodamine B with degradation efficiency of 93%. This work provides a novel and facile method to produce the nanocomposites as efficient photocatalysts for the removal of organic contaminants from aqueous solution.

  12. Simultaneous Determination of Adenine and Guanine Using Cadmium Selenide Quantum Dots-Graphene Oxide Nanocomposite Modified Electrode.

    Science.gov (United States)

    Kalaivani, Arumugam; Narayanan, Sangilimuthu Sriman

    2015-06-01

    A novel electrochemical sensor was fabricated by immobilizing Cadmium Selenide Quantum Dots (CdSe QDs)-Graphene Oxide (GO) nanocomposite on a paraffin wax impregnated graphite electrode (PIGE) and was used for the simultaneous determination of adenine and guanine. The CdSe QDs-GO nanocomposite was prepared by ultrasonication and was characterized with spectroscopic and microscopic techniques. The nanocomposite modified electrode was characterized by cyclic voltammetry (CV). The modified electrode showed excellent electrocatalytic activity towards the oxidative determination of adenine and guanine with a good peak separation of 0.31 V. This may be due to the high surface area and fast electron transfer kinetics of the nanocomposite. The modified electrode exhibited wide linear ranges from 0.167 μM to 245 μM for Guanine and 0.083 μM to 291 μM for Adenine with detection limits of 0.055 μM Guanine and 0.028 μM of Adenine (S/N = 3) respectively. Further, the modified electrode was used for the quantitative determination of adenine and guanine in herring sperm DNA with satisfactory results. The modified electrode showed acceptable selectivity, reproducibility and stability under optimal conditions.

  13. Development of Piezoelectric Zinc Oxide Nanoparticle-Poly(Vinylidene Fluoride) Nanocomposites for Sensing and Actuation

    Science.gov (United States)

    Dodds, John Steven

    Structural health monitoring (SHM) is vital for detecting the onset of damage and for preventing catastrophic failure of civil infrastructure systems. In particular, piezoelectric transducers have the ability to excite and actively interrogate structures (e.g., using surface waves) while measuring their response for damage detection. In fact, piezoelectric transducers such as lead zirconate titanate (PZT) and poly(vinylidene fluoride) (PVDF) have been used for various laboratory and field tests and have demonstrated significant advantages as compared to visual inspection and vibration-based methods, to name a few. However, PZTs are inherently brittle, and PVDF films do not possess high piezoelectricity, thereby limiting each of these devices to certain specific applications. Piezoelectric nanocomposites, which enjoy a combination of the best properties of these material types, are at the forefront of emerging SHM technologies. The objective of this study is to design, characterize, and validate piezoelectric nanocomposites consisting of zinc oxide (ZnO) nanoparticles assembled in a PVDF copolymer matrix for sensing and actuation. It will be shown that these films provide greater mechanical flexibility as compared to PZTs, yet possess enhanced piezoelectricity as compared to pristine PVDF copolymers. The results obtained from this research will be crucial for future SHM applications using these piezoelectric nanocomposites. This study began with spin coating dispersed ZnO-based solutions for piezoelectric nanocomposite fabrication. The concentration of ZnO nanoparticles was varied from 0 to 20 wt.% (in 5% increments) to determine their influence on bulk film piezoelectricity. Second, their electric polarization responses were obtained for quantifying thin film remnant polarization, which is directly correlated to piezoelectricity. Based on these results, the films were poled at 50 MV-m-1 to permanently align film electrical domains and to enhance bulk film

  14. Green Preparation of Epoxy/Graphene Oxide Nanocomposites Using a Glycidylamine Epoxy Resin as the Surface Modifier and Phase Transfer Agent of Graphene Oxide.

    Science.gov (United States)

    Tang, Xinlei; Zhou, Yang; Peng, Mao

    2016-01-27

    In studies of epoxy/graphene oxide (GO) nanocomposites, organic solvents are commonly used to disperse GO, and vigorous mechanical processes and complicated modification of GO are usually required, increasing the cost and hindering the development and application of epoxy nanocomposites. Here, we report a green, facile, and efficient method of preparing epoxy/GO nanocomposites. When triglycidyl para-aminophenol (TGPAP), a commercially available glycidyl amine epoxy resin with one tertiary amine group per molecule, is used as both the surface modifier and phase transfer agent of GO, GO can be directly and rapidly transferred from water to diglycidyl ether of bisphenol A and other types of epoxy resins by manual stirring under ambient conditions, whereas GO cannot be transferred to these epoxy resins in the absence of TGPAP. The interaction between TGPAP and GO and the effect of the TGPAP content on the dispersion of GO in the epoxy matrix were investigated systematically. Superior dispersion and exfoliation of GO nanosheets and remarkably improved mechanical properties, including tensile and flexural properties, toughness, storage modulus, and microhardness, of the epoxy/GO nanocomposites with a suitable amount of TGPAP were demonstrated. This method is organic-solvent-free and technically feasible for large-scale preparation of high-performance nanocomposites; it opens up new opportunities for exploiting the unique properties of graphene or even other nanofillers for a wide range of applications.

  15. Methanol oxidation at carbon paste electrodes modified with (Pt–Ru)/carbon aerogels nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Fort, Carmen I., E-mail: iladiu@chem.ubbcluj.ro [Laboratory of Electrochemical Research and Nonconventional Materials, Babes-Bolyai University, Arany Janos 11, RO-400028, Cluj-Napoca (Romania); Cotet, Liviu C. [Laboratory of Electrochemical Research and Nonconventional Materials, Babes-Bolyai University, Arany Janos 11, RO-400028, Cluj-Napoca (Romania); Vasiliu, Florin [The National Institute of Materials Physics, Atomistilor str. 105 bis, PO Box MG. 7, Magurele, RO 077125, Bucharest (Romania); Marginean, Petre [National Institute for Research and Development of Isotopic and Molecular Technologies, RO 400293, Cluj-Napoca (Romania); Danciu, Virginia; Popescu, Ionel C. [Laboratory of Electrochemical Research and Nonconventional Materials, Babes-Bolyai University, Arany Janos 11, RO-400028, Cluj-Napoca (Romania)

    2016-04-01

    Mesoporous carbon aerogels (CAs) impregnated with (Pt–Ru) nanoparticles were prepared, incorporated into carbon paste electrodes (CPEs) and investigated as electrocatalysts for CH{sub 3}OH electro-oxidation. The sol–gel method, followed by supercritical drying with liquid CO{sub 2} and thermal pyrolysis in an inert atmosphere, was used to obtain high mesoporous CAs. (Pt–Ru)/CAs nanocomposites with various (Pt–Ru) loading were prepared by using Ru(AcAc){sub 3} and H{sub 2}PtCl{sub 6} as metal precursors and the impregnation method. The morpho-structural peculiarities of the so prepared (Pt–Ru)/CAs electrocatalysts were examined by using elemental analysis, N{sub 2} adsorption-desorption isotherms, transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), energy dispersive X-ray (EDX) and selected area electron diffraction (SAED). Cyclic voltammetry measurements, carried out at (Pt–Ru)/CA-CPEs incorporating nanocomposites with various Pt–Ru loading and different specific surface areas, showed that CA with the highest specific surface area (843 m{sup 2}/g) and impregnated with 6% (w/w) (Pt–Ru) nanoparticles exhibit the best CH{sub 3}OH electro-oxidation efficiency. The Michaelis–Menten formalism was used to describe the dependence of the oxidation peak current on the CH{sub 3}OH concentration, allowing the estimation of the modified electrodes sensitivities. Thus, for (Pt–Ru, 10%)/CA{sub 535}-CPE was observed the highest sensitivity (12.5 ± 0.8 mA/M) and, at the same time, the highest maximum current density ever reported (153.1 mA/cm{sup 2} for 2 M CH{sub 3}OH and an applied potential of 600 mV vs. SHE). - Highlights: • (Pt–Ru) nanoparticles were deposited on high mesoporous carbon aerogels (CAs). • (Pt–Ru)/CAs were characterized by TEM, EDX, SAED and N{sub 2} adsorption-desorption. • Carbon paste electrodes modified with (Pt–Ru)/CA were used for CH{sub 3}OH oxidation. • (Pt–Ru, 10

  16. Electrosynthesized polytyramine-copper oxalate nanocomposite on copper electrode for electrocatalytic oxidation of methanol in alkaline medium

    Institute of Scientific and Technical Information of China (English)

    Robab Abbasi a; Khalil Farhadi a; Sepideh Banisaeid a; Nader Nowroozi Pesyan a; Arezu Jamali a; Fatemeh Rahmani b

    2014-01-01

    A polytyramine-copper oxalate nanocomposite modified copper (PTCOxNMC) electrode prepared by electropolymerization was examined for electrocatalytic activity towards the oxidation of meth-anol in alkaline solution using cyclic voltammetry and impedance spectroscopy. The prepared PTCOxNMC electrode showed a significantly high response for adsorbed methanol oxidation. The effects of various parameters such as potential scan rate and methanol concentration on the elec-trocatalytic oxidation at the surface of the PTCOxNMC electrode were investigated. Spectrometry techniques such as Fourier transform infrared spectroscopy and scanning electron microscopy were used to determine the surface physical characteristics of the modified electrode and revealed that the polytyramine-copper oxalate nanocomposite particles were highly dispersed on the surface of the copper electrode with a narrow size up to 40 nm. The very high current density obtained for the catalytic oxidation may have resulted from the high electrode surface area caused by modifica-tion with the poly-tyramine-copper oxalate nanocomposite.

  17. Photodegradation of basic dyes using nanocomposite (Ag-zinc oxide-copper oxide and kinetic studies

    Directory of Open Access Journals (Sweden)

    Nasrin Khorshidi

    2016-05-01

    Full Text Available In this paper, Ag/ZnO/CuO nanocomposite (AZCN synthesized and its dye degradation ability in the presence of UV irradiation from colored wastewater was studied. The characteristics of AZCN were investigated using Fourier transform infrared (FTIR, scanning electron microscope (SEM and X-ray diffraction (XRD. The photocatalytic activity was evaluated by photodegradation of Basic Red 18 (BR18 and Basic Violet 16 (BV16 as a model contaminant. The effects of AZCN dosage, initial dye concentration and salt on dye degradation were investigated. Kinetics analysis indicated that the dye degradation rates could be approximated at pseudo-first order model. The results indicated that AZCN as a photocatalyst could be used to degrade dyes from wastewater.

  18. A non-enzymatic amperometric hydrogen peroxide sensor based on iron nanoparticles decorated reduced graphene oxide nanocomposite.

    Science.gov (United States)

    Amanulla, Baishnisha; Palanisamy, Selvakumar; Chen, Shen-Ming; Velusamy, Vijayalakshmi; Chiu, Te-Wei; Chen, Tse-Wei; Ramaraj, Sayee Kannan

    2017-02-01

    A simple and facile green process was used for the synthesis of iron nanoparticles (FeNPs) decorated reduced graphene oxide (rGO) nanocomposite by using Ipomoea pes-tigridis leaf extract as a reducing and stabilizing agent. The as-prepared rGO/FeNPs nanocomposite was characterized by transmission electron microscopy, X-ray spectroscopy and Fourier transform infrared spectroscopy. The nanocomposite was further modified on the glassy carbon electrode and used for non-enzymatic sensing of hydrogen peroxide (H2O2). Cyclic voltammetry results reveal that rGO/FeNPs nanocomposite has excellent electro-reduction behavior to H2O2 when compared to the response of FeNPs and rGO modified electrodes. Furthermore, the nanocomposite modified electrode shows 9 and 6 folds enhanced reduction current response to H2O2 than that of rGO and FeNPs modified electrodes. Amperometric method was further used to quantify the H2O2 using rGO/FeNPs nanocomposite, and the response was linear over the concentration ranging from 0.1μM to 2.15mM. The detection limit and sensitivity of the sensor were estimated as 0.056μM and 0.2085μAμM(-1)cm(-2), respectively. The fabricated sensor also utilized for detection of H2O2 in the presence of potentially active interfering species, and found high selectivity towards H2O2. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. 3D Flower-like β-MnO2/Reduced Graphene Oxide Nanocomposites for Catalytic Ozonation of Dichloroacetic Acid

    Science.gov (United States)

    Li, Gang; Li, Kezheng; Liu, Aijuan; Yang, Ping; Du, Yukou; Zhu, Mingshan

    2017-03-01

    Considering the potential use of manganese oxide based nanocomposite in catalytic ozonation of water contaminant, we report unique three-dimensional (3D) nanoarchitectures composed of β-MnO2 and reduced graphene oxide (RGO) for catalytic ozonation of dichloroacetic acid (DCAA) from drinking water. The catalytic results show that the 3D β-MnO2/RGO nanocomposites (FMOG) can be used as efficient and stable ozonation catalysts to eliminate DCAA from water. The probable mechanism of catalytic ozonation was also proposed by detecting intermediates using gas chromatography-mass spectrometry. This result likely paves a facile avenue and initiates new opportunities for the exploration of heterogeneous catalysts for the removal of disinfection by-products from drinking water.

  20. Pulse electrodeposited nickel-indium tin oxide nanocomposite as an electrocatalyst for non-enzymatic glucose sensing.

    Science.gov (United States)

    Sivasakthi, P; Ramesh Bapu, G N K; Chandrasekaran, Maruthai

    2016-01-01

    Nickel and nickel-ITO nanocomposite on mild steel substrate were prepared by pulse electrodeposition method from nickel sulphamate electrolyte and were examined as electrocatalysts for non-enzymatic glucose sensing. The surface morphology, chemical composition, preferred orientation and oxidation states of the nickel metal ion in the deposits were characterized by SEM, EDAX, XRD and XPS. Electrochemical sensing of glucose was studied by cyclic voltammetry and amperometry. The modified Ni-ITO nanocomposite electrode showed higher electrocatalytic activity for the oxidation of glucose in alkaline medium and exhibited a linear range from 0.02 to 3.00 mM with a limit of detection 3.74 μM at a signal-to-noise ratio of 3. The higher selectivity, longer stability and better reproducibility of this electrode compared to nickel in the sensing of glucose are pointers for exploitation in practical clinical applications.

  1. Exceptional oxygen barrier performance of pullulan nanocomposites with ultra-low loading of graphene oxide

    Science.gov (United States)

    Uysal Unalan, Ilke; Wan, Chaoying; Figiel, Łukasz; Olsson, Richard T.; Trabattoni, Silvia; Farris, Stefano

    2015-07-01

    Polymer nanocomposites are increasingly important in food packaging sectors. Biopolymer pullulan is promising in manufacturing packaging films or coatings due to its excellent optical clarity, mechanical strength, and high water-solubility as compared to other biopolymers. This work aims to enhance its oxygen barrier properties and overcome its intrinsic brittleness by utilizing two-dimensional planar graphene oxide (GO) nanoplatelets. It has been found that the addition of only 0.2 wt% of GO enhanced the tensile strength, Young’s modulus, and elongation at break of pullulan films by about 40, 44 and 52%, respectively. The light transmittance at 550 nm of the pullulan/GO films was 92.3% and haze values were within 3.0% threshold, which meets the general requirement for food packaging materials. In particular, the oxygen permeability coefficient of pullulan was reduced from 6337 to 2614 mL μm m-2 (24 h-1) atm-1 with as low as 0.05 wt% of GO loading and further to 1357 mL μm m-2 (24 h-1) atm-1 when GO concentration reached 0.3 wt%. The simultaneous improvement of the mechanical and oxygen barrier properties of pullulan was ascribed to the homogeneous distribution and prevalent unidirectional alignment of GO nanosheets, as determined from the characterization and theoretical modelling results. The exceptional oxygen barrier properties of pullulan/GO nanocomposites with enhanced mechanical flexibility and good optical clarity will add new values to high performance food packaging materials.

  2. Design and synthesis of mixed oxides nanoparticles for biofuel applications

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Senniang [Iowa State Univ., Ames, IA (United States)

    2010-05-15

    The work in this dissertation presents the synthesis of two mixed metal oxides for biofuel applications and NMR characterization of silica materials. In the chapter 2, high catalytic efficiency of calcium silicate is synthesized for transesterfication of soybean oil to biodisels. Chapter 3 describes the synthesis of a new Rh based catalyst on mesoporous manganese oxides. The new catalyst is found to have higher activity and selectivity towards ethanol. Chapter 4 demonstrates the applications of solid-state Si NMR in the silica materials.

  3. Development of advanced mixed oxide fuels for plutonium management

    Energy Technology Data Exchange (ETDEWEB)

    Eaton, S.; Beard, C.; Buksa, J.; Butt, D.; Chidester, K.; Havrilla, G.; Ramsey, K.

    1997-06-01

    A number of advanced Mixed Oxide (MOX) fuel forms are currently being investigated at Los Alamos National Laboratory that have the potential to be effective plutonium management tools. Evolutionary Mixed Oxide (EMOX) fuel is a slight perturbation on standard MOX fuel, but achieves greater plutonium destruction rates by employing a fractional nonfertile component. A pure nonfertile fuel is also being studied. Initial calculations show that the fuel can be utilized in existing light water reactors and tailored to address different plutonium management goals (i.e., stabilization or reduction of plutonium inventories residing in spent nuclear fuel). In parallel, experiments are being performed to determine the feasibility of fabrication of such fuels. Initial EMOX pellets have successfully been fabricated using weapons-grade plutonium.

  4. Novel Electrospun Polylactic Acid Nanocomposite Fiber Mats with Hybrid Graphene Oxide and Nanohydroxyapatite Reinforcements Having Enhanced Biocompatibility

    OpenAIRE

    Chen Liu; Hoi Man Wong; Kelvin Wai Kwok Yeung; Sie Chin Tjong

    2016-01-01

    Graphene oxide (GO) and a nanohydroxyapatite rod (nHA) of good biocompatibility were incorporated into polylactic acid (PLA) through electrospinning to form nanocomposite fiber scaffolds for bone tissue engineering applications. The preparation, morphological, mechanical and thermal properties, as well as biocompatibility of electrospun PLA scaffolds reinforced with GO and/or nHA were investigated. Electron microscopic examination and image analysis showed that GO and nHA nanofillers refine t...

  5. Synthesis of fullerene-, carbon nanotube-, and graphene-TiO₂ nanocomposite photocatalysts for selective oxidation: a comparative study.

    Science.gov (United States)

    Yang, Min-Quan; Zhang, Nan; Xu, Yi-Jun

    2013-02-01

    A series of TiO(2)-graphene (GR), -carbon nanotube (CNT), and -fullerene (C(60)) nanocomposite photocatalysts with different weight addition ratios of carbon contents are synthesized via a combination of sol-gel and hydrothermal methods. Their structures and properties are determined by the X-ray diffraction (XRD), UV-vis diffuse reflectance spectra (DRS), transmission electron microscopy (TEM), nitrogen adsorption-desorption, and photoelectrochemical measurements. Photocatalytic selective oxidation of benzyl alcohol to benzaldehyde is employed as a model reaction to evaluate the photocatalytic activity of the TiO(2)-carbon (GR, CNT, and C(60)) nanocomposites under visible light irradiation. The results reveal that incorporating TiO(2) with carbon materials can extend the adsorption edge of all the TiO(2)-carbon nanocomposites to the visible light region. For TiO(2)-GR, TiO(2)-CNT, and TiO(2)-C(60) nanocomposites, the photocatalytic activities of the composites with optimum ratios, TiO(2)-0.1% GR, TiO(2)-0.5% CNT, and TiO(2)-1.0% C(60), are very close to each other along with the irradiation time. Furthermore, the underlying reaction mechanism for the photocatalytic selective oxidation of benzyl alcohol to benzaldehyde over TiO(2)-carbon nanocomposites has been explored using different radical scavenger techniques, suggesting that TiO(2)-carbon photocatalysts follow the analogous oxidation mechanism toward selective oxidation of benzyl alcohol. The addition of different carbon materials has no significant influence on the crystal phase, particle size, and the morphology of TiO(2). Therefore, it can be concluded, at least for nanocomposites of TiO(2)-carbon (GR, CNT, and C(60)) obtained by the present approach, that there is no much difference in essence on affecting the photocatalytic performance of semiconductor TiO(2) among these three different carbon allotropes, GR, CNT, and C(60). Our findings point to the importance of a comparative study of semiconductor

  6. Structure Characterization of Semiconducting Tin and Tungsten Mixed Oxides

    Science.gov (United States)

    Solis, J. L.; Frantti, J.; Lantto, V.; Häggström, L.; Wikner, M.

    Mixed-oxide powders of tin and tungsten were made by heating various mixtures of SnO and WO3 powders, corresponding to the nominal formula SnxWO3+x with x between 0.5 and 2.0, in an argon atmosphere at 600°C for 15 hours. The α-SnWO4 phase was the result of heating of an equi-molar mixture of SnO and WO3 powders. In addition to 119Sn Mössbauer experiments, X-ray diffraction and Raman spectroscopy were used to study the phase structures of the mixed-oxide powders. Mössbauer spectra from all samples show a small peak at ∽0mm/s from phase(s) like rutile SnO2, and a larger peak doublet centred at ∽3.4mm/s from the α-SnWO4 phase, where tin is in the form Sn4+ and Sn2+, respectively. Another peak doublet centred at ∽3.0mm/s was needed to obtain reasonable fits for samples with x≥1.3. This doublet originates from an undocumented phase where tin is also in the divalent form Sn2+. 119Sn Mössbauer spectroscopy made it possible to reveal the relative amounts of the two valence states of tin in the mixed-oxide structures. Raman spectroscopy as the other probe for ``local'' structures was insensitive to reveal the changes in the phase structures between different mixed-oxide samples up to x=1.72, but an extra peak at ∽890cm-1 in the Raman spectrum from the sample with x=2.0 indicates also the presence of the undocumented phase.

  7. Microstructure and thermophysical characterization of mixed oxide fuels

    Energy Technology Data Exchange (ETDEWEB)

    Freibert, Franz J [Los Alamos National Laboratory; Salich, Tarik A [Los Alamos National Laboratory; Schwartz, Daniel S [Los Alamos National Laboratory; Hampel, Fred G [Los Alamos National Laboratory; Mitchell, Jeremy N [Los Alamos National Laboratory; Davis, Charles C [Los Alamos National Laboratory; Neuman, Angelique D [Los Alamos National Laboratory; Willson, Steve P [Los Alamos National Laboratory; Dunwoody, John T [Los Alamos National Laboratory

    2009-01-01

    Pre-irradiated thermodynamic and microstructural properties of nuclear fuels form the necessary set of data against which to gauge fuel performance and irradiation damage evolution. This paper summarizes recent efforts in mixed-oxide and minor actinide-bearing mixed-oxide ceramic fuels fabrication and characterization at Los Alamos National Laboratory. Ceramic fuels (U{sub 1-x-y-z}u{sub x}Am{sub y}Np{sub z})O{sub 2} fabricated in the compositional ranges of 0.19 {le} x {le} 0.3 Pu, 0 {le} y {le} 0.05 Am, and O {le} z {le} O.03 Np exhibited a uniform crystalline face-centered cubic phase with an average grain size of 14{micro}m; however, electron microprobe analysis revealed segregation of NpO{sub 2} in minor actinide-bearing fuels. Immersion density and porosity analysis demonstrated an average density of 92.4% theoretical for mixed-oxide fuels and an average density of 89.5 % theoretical density for minor actinide-bearing mixed-oxide fuels. Examined fuels exhibited mean thermal expansion value of 12.56 x 10{sup -6} C{sup -1} for temperature range (100 C < T < 1500 C) and ambient temperature Young's modulus and Poisson's ratio of 169 GPa and of 0.327, respectively. Internal dissipation as determined from mechanical resonances of these ceramic fuels has shown promise as a tool to gauge microstructural integrity and to interrogate fundamental properties.

  8. Controlled oxidative synthesis of Bi nanoparticles and emission centers in bismuth glass nanocomposites for photonic application

    Science.gov (United States)

    Singh, Shiv Prakash; Karmakar, Basudeb

    2011-09-01

    Here we demonstrate an oxidative process to control metallic bismuth (Bi 0) nanoparticles (NPs) creation in bismuth glass nanocomposites by using K 2S 2O 8 as oxidant and enhanced transparency of bismuth glasses. Formation of Bi 0 NPs has been monitored by their distinct surface plasmon resonance (SPR) band at 460 nm in the UV-visible absorption spectra. It is further confirmed by the transmission electron microscopy (TEM) images which disclose the formation of spherical Bi 0 NPs whereas the selected area electron diffraction (SAED) pattern reveals their crystalline rhombohedral phase. These glasses are found to exhibit visible and near infrared (NIR) luminescence bands at 630 and 843 nm respectively on excitation at 460 nm of the SPR band. It is realized that the luminescence center of bismuth species is an uncertain issue, however, it is reasonable to consider that the emission band at 630 nm is due to the combination of 2D 5/2 → 4S 3/2 of Bi 0 and 2P 3/2 (1) → 2P 1/2 of Bi 2+ transitions, and that of NIR emission band at 843 nm is attributed to the 2D 3/2 → 4S 3/2 of Bi 0 transition.

  9. Reversible wettability conversion of electrodeposited graphene oxide/titania nanocomposite coating: Investigation of surface structures

    Energy Technology Data Exchange (ETDEWEB)

    Naghdi, Samira; Jaleh, Babak, E-mail: bkjaleh@yahoo.com; Shahbazi, Nima

    2016-04-15

    Graphical abstract: - Highlights: • Electrophoretic deposition of Graphene oxide/titania on aluminum surface. • Superhydrophilicity of the GO/TiO{sub 2} coating (WCA ≈ 5°). • Wettability switching of the coating via thermal annealing to superhyrophobic. • The superhydrophobic coating was changed to superhydrophilic due to UV irradiance. • The GO/TiO{sub 2} coating has reversible wettability. - Abstract: Graphene oxide/titania (GO/TiO{sub 2}) nanocomposite have been successfully prepared by a simple method and deposited on the surface of aluminum (Al) by the electrophoretic deposition method. The effect of thermal annealing on wettability of GO/TiO{sub 2} coating has been investigated. According to the obtained results, the water contact angle (WCA) increased with an increase in annealing temperature which may be attributed to the regulation of coating from superhydrophilic (WCA ≈ 5°) to superhydrophobic (WCA ≈ 148°) via thermal annealing. Moreover, the superhydrophobic coating was changed to a superhydrophilic one by using ultraviolet irradiation and this effect was reversible by heat treatment.

  10. Metal oxide/polyaniline nanocomposites: Cluster size and composition dependent structural and magnetic properties

    Indian Academy of Sciences (India)

    Raksha Sharma; Rakesh Malik; Subhalakshmi Lamba; S Annapoorni

    2008-06-01

    Nanocomposites of iron oxide with conducting polymer in the form of powders of varying compositions have been studied to understand the effects of particle size, cluster size and magnetic inter-particle interactions. The sizes of the nanoparticles were estimated to be ∼ 10–20 nm from the X-ray diffraction (XRD) and the transmission electron micrographs (TEM). XRD shows a single crystalline phase for the -Fe2O3. The presence of conducting polymer was confirmed through Fourier transform infrared (FTIR) spectroscopy. The amount of polymer present in the composite, the transition temperature of iron oxide and the thermal stability of polymer was determined through thermogravimetric and differential thermal analysis (TGA–DTA). The room temperature magnetic hysteresis measurements show reduction in saturation magnetization with increasing polymer concentrations. A low value of coercivity was observed for low polymer composites. On increasing the polymer concentration, the coercivity and remanence become negligible indicating a superparamagnetic phase at room temperature. Beyond a certain composition, the system shows paramagnetic behaviour which is also confirmed through zero field cooled–field cooled (ZFC–FC) measurements. We also report preliminary results on the magnetic properties of self standing sheets prepared using -Fe2O3 and NiFe2O4 nanoparticles and conducting polymers.

  11. Near-Infrared Light-Responsive Poly(N-isopropylacrylamide)/Graphene Oxide Nanocomposite Hydrogels with Ultrahigh Tensibility.

    Science.gov (United States)

    Shi, Kun; Liu, Zhuang; Wei, Yun-Yan; Wang, Wei; Ju, Xiao-Jie; Xie, Rui; Chu, Liang-Yin

    2015-12-16

    Novel near-infrared (NIR) light-responsive poly(N-isopropylacrylamide)/graphene oxide (PNIPAM-GO) nanocomposite hydrogels with ultrahigh tensibility are prepared by incorporating sparse chemical cross-linking of small molecules with physical cross-linking of graphene oxide (GO) nanosheets. Combination of the GO nanosheets and thermoresponsive poly(N-isopropylacrylamide) (PNIPAM) polymeric networks provides the hydrogels with an excellent NIR light-responsive property. The ultrahigh tensibility of PNIPAM-GO nanocomposite hydrogels is achieved by simply using a very low concentration of N,N'-methylenebis(acrylamide) (BIS) molecules as chemical cross-linkers to generate a relatively homogeneous structure with flexible long polymer chains and rare chemically cross-linked dense clusters. Moreover, the oxidized groups of GO nanosheets enable the formation of a hydrogen bond interaction with the amide groups of PNIPAM chains, which could physically cross-link the PNIPAM chains to increase the toughness of the hydrogel networks. The prepared PNIPAM-GO nanocomposite hydrogels with ultrahigh tensibility exhibit rapid, reversible, and repeatable NIR light-responsive properties, which are highly promising for fabricating remote light-controlled devices, smart actuators, artificial muscles, and so on.

  12. Chitosan/zinc oxide-polyvinylpyrrolidone (CS/ZnO-PVP) nanocomposite for better thermal and antibacterial activity.

    Science.gov (United States)

    Karpuraranjith, M; Thambidurai, S

    2017-03-06

    A new biopolymer based ZnO-PVP nanocomposite was successfully synthesized by single step in situ precipitation method using chitosan as biosurfactant, zinc chloride as a source material, PVP as stabilizing agent and sodium hydroxide as precipitating agent. The chemical bonding and crystalline behaviors of chitosan, zinc oxide and PVP were confirmed by FT-IR and XRD analysis. The biopolymer connected ZnO particles intercalated PVP matrix was layer and rod like structure appeared in nanometer range confirmed by HR-SEM and TEM analysis. The surface topography image of CS/ZnO-PVP nanocomposite was obtained in the average thickness of 12nm was confirmed by AFM analysis. Thermal stability of cationic biopolymer based ZnO intercalated PVP has higher stability than CS-PVP and chitosan. Consequently, antimicrobial activity of chitosan/ZnO-PVP matrix acts as a better microbial inhibition activity than PVP-ZnO nanocomposite. The obtained above results demonstrate that CS and ZnO intercalated PVP matrix has better reinforced effect than other components. Therefore, Chitosan/ZnO-PVP nanocomposite may be a promising material for the biomedical applications.

  13. Surfactant-assisted hydrothermal synthesis of TiO2/reduced graphene oxide nanocomposites and their photocatalytic performances

    Science.gov (United States)

    Hu, Ju; Li, Hansheng; Muhammad, Sohail; Wu, Qin; Zhao, Yun; Jiao, Qingze

    2017-09-01

    Titanium dioxide/reduced graphene oxide nanocomposites (TiO2/RGO-X, X=S, T or C, was denoted sodium dodecyl benzene sulfonate, Triton X-100 and cetyl trimethyl ammonium bromide, respectively) were synthesized using a one-step surfactant-assisted hydrothermal method. The characterization of phase structure and morphology of the as-obtained nanocomposites reveals that TiO2 in the TiO2/RGO-X exhibits the morphologies of nanoparticles, nanowires and array-like nanowires on the surface of RGO, respectively. Compared with the control TiO2/RGO nanocomposite, TiO2/RGO-X presents an excellent photocatalytic activity. With uniform array-like TiO2 nanowires on the surface of RGO, the TiO2/RGO-C shows a significant enhancement in the photocatalytic efficiency. Besides, a deeper insight into the growth mechanism of TiO2/RGO nanocomposites is put forward. This work indicates that the surfactant-assisted hydrothermal method is an effective approach to improve the structure, morphology and photocatalytic performance of TiO2/RGO composites. Moreover, the surfactants with various types can interact with the precursors of TiO2 and RGO in different ways.

  14. Preparation of the Pt nanoparticles decorated poly(N-acetylaniline)/MWNTs nanocomposite and its electrocatalytic oxidation toward formaldehyde

    Energy Technology Data Exchange (ETDEWEB)

    Jiang Chunming; Chen Hui; Yu Cheng; Zhang Song; Liu Baohong [Department of Chemistry, Fudan University, Shanghai, 200433 (China); Kong Jilie [Department of Chemistry, Fudan University, Shanghai, 200433 (China); Institutes of Biomedical Science, Fudan University, Shanghai, 200433 (China); Research Center for Analysis and Measurement, Fudan University, Shanghai, 200433 (China)], E-mail: jlkong@fudan.edu.cn

    2009-01-01

    In this work, a novel 3D nanocomposite is presented, which is consisted of poly(N-acetylaniline) (PAANI)/multi-walled carbon nanotubes (MWNTs) nanorods (in which the inner layer was comprised of MWNTs and the outer layer was PAANI, forming a core-shell structure) and the decorated Pt nanoparticles. Electrochemical techniques (such as electrochemical impedance spectroscopy (EIS)), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), X-ray diffraction (XRD) and transmission electron microscopy (TEM) are used to characterize the nanocomposite. The resulting Pt/PAANI/MWNTs nanocomposite can be served as a higher efficient catalyst for the electrochemical oxidation of formaldehyde at 0.41 V with the catalytic current of 0.73 mA, which was accompanied with about 45 mV potential negative shifts and two-fold increase in peak current comparison to the Pt/PAANI. These results reveal that the Pt/PAANI/MWNTs nanocomposite film is quite promising in the fuel cell applications.

  15. Hierarchical nanocomposites of vanadium oxide thin film anchored on graphene as high-performance cathodes in li-ion batteries.

    Science.gov (United States)

    Li, Zhe-Fei; Zhang, Hangyu; Liu, Qi; Liu, Yadong; Stanciu, Lia; Xie, Jian

    2014-11-12

    Hierarchical nanocomposites of V2O5 thin film anchored on graphene sheets were prepared by slow hydrolysis of vanadyl triisobutoxide on graphene oxide followed by thermal treatment. The nanocomposite possessed a hierarchical structure of thin V2O5 film uniformly grown on graphene, leading to a high specific surface area and a good electronic/ionic conducting path. When used as the cathode material, the graphene/V2O5 nanosheet nanocomposites exhibit higher specific capacity, better rate performance, and longer cycle life, as compared to the pure V2O5. The nanocomposite cathode was able to deliver a specific capacity of 243 mAh/g, 191 mAh/g, and 86 mAh/g at a current density of 50 mA/g, 500 mA/g, and 15 A/g, respectively. Even after 300 cycles at 500 mA/g, the composite electrode still exhibited a specific capacity of ∼ 122 mAh/g, which corresponds to ∼ 64% of its initial capacity. This enhanced electrochemical performance can be attributed to facile electron transport between graphene and V2O5, fast Li-ion diffusion within the electrode, the high surface area of the composites, and a pore structure that can accommodate the volume change during lithiation/delithiation, which results from the unique hierarchical nanostructure of the V2O5 anchored on graphene.

  16. Facile preparation of polypyrrole/graphene oxide nanocomposites with large areal capacitance using electrochemical codeposition for supercapacitors

    Science.gov (United States)

    Zhou, Haihan; Han, Gaoyi; Xiao, Yaoming; Chang, Yunzhen; Zhai, Hua-Jin

    2014-10-01

    A simple and low-cost electrochemical codeposition method has been introduced to fabricate polypyrrole/graphene oxide (PPy/GO) nanocomposites and the areal capacitance of conducting polymer/GO composites is reported for the first time. Fourier transform infrared spectroscopy (FTIR), Transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD) are implemented to determine the PPy/GO nanocomposites are successfully prepared and the interaction between PPy and GO. The as-prepared PPy/GO nanocomposites show the curly sheet-like morphology, superior capacitive behaviors and cyclic stability. Furthermore, the varying deposition time is implemented to investigate the impact of the loading amount on electrochemical behavior of the composites, and a high areal capacitance of 152 mF cm-2 is achieved at 10 mV s-1 CV scan. However, the thicker films caused by the long deposition time would result in larger diffusion resistance of electrolyte ions, consequently exhibit the relatively lower capacitance value at the high current density. The GCD tests indicate moderate deposition time is more suitable for the fast charge/discharge. Considering the very simple and effective synthetic process, the PPy/GO nanocomposites with relatively high areal capacitance are competitive candidate for supercapacitor application, and its capacitive performances can be easily tuned by varying the deposition time.

  17. Novel Electrospun Polylactic Acid Nanocomposite Fiber Mats with Hybrid Graphene Oxide and Nanohydroxyapatite Reinforcements Having Enhanced Biocompatibility

    Directory of Open Access Journals (Sweden)

    Chen Liu

    2016-08-01

    Full Text Available Graphene oxide (GO and a nanohydroxyapatite rod (nHA of good biocompatibility were incorporated into polylactic acid (PLA through electrospinning to form nanocomposite fiber scaffolds for bone tissue engineering applications. The preparation, morphological, mechanical and thermal properties, as well as biocompatibility of electrospun PLA scaffolds reinforced with GO and/or nHA were investigated. Electron microscopic examination and image analysis showed that GO and nHA nanofillers refine the diameter of electrospun PLA fibers. Differential scanning calorimetric tests showed that nHA facilitates the crystallization process of PLA, thereby acting as a nucleating site for the PLA molecules. Tensile test results indicated that the tensile strength and elastic modulus of the electrospun PLA mat can be increased by adding 15 wt % nHA. The hybrid nanocomposite scaffold with 15 wt % nHA and 1 wt % GO fillers exhibited higher tensile strength amongst the specimens investigated. Furthermore, nHA and GO nanofillers enhanced the water uptake of PLA. Cell cultivation, 3-(4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide (MTT and alkaline phosphatase tests demonstrated that all of the nanocomposite scaffolds exhibit higher biocompatibility than the pure PLA mat, particularly for the scaffold with 15 wt % nHA and 1 wt % GO. Therefore, the novel electrospun PLA nanocomposite scaffold with 15 wt % nHA and 1 wt % GO possessing a high tensile strength and modulus, as well as excellent cell proliferation is a potential biomaterial for bone tissue engineering applications.

  18. Mixed metal oxide crystalline powders and method for the synthesis thereof

    Energy Technology Data Exchange (ETDEWEB)

    Joyce, I.H.; Blonski, R.P.; Maloney, J.J.; Welch, J.J.; Pipoly, R.A.; Byrne, C.J.

    1993-07-20

    A method is described for the solid state synthesis of mixed metal oxide crystalline powders comprising the steps of: preparing a raw material mixture containing at least two different metal cations; adding a template material to said mixture and blending it therewith; initiating formation of a mixed metal oxide by calcination of said mixture and said template material, whereby particles of the mixed metal oxides are formed in powder form; and thereafter recovering said mixed metal oxide particles.

  19. Selective oxidation of benzylic alcohols using copper-manganese mixed oxide nanoparticles as catalyst

    Directory of Open Access Journals (Sweden)

    Roushown Ali

    2015-07-01

    Full Text Available The catalytic activity of copper-manganese (CuMn2 mixed oxide nanoparticles (Cu/Mn = 1:2 has been studied for the selective oxidation of benzylic alcohols to the corresponding aldehydes using molecular oxygen as an oxidizing agent. The CuMn2 mixed oxide showed excellent catalytic activity for the oxidation of benzylic alcohols to the corresponding aldehydes with high selectivity (>99%. The complete conversion (100% of all the benzylic alcohols to the corresponding aldehydes is achieved within a short reaction period at 102 °C. The catalytic performance is obtained to be dependent on the electronic and steric effects of the substituents present on the phenyl ring. Electron withdrawing and bulky groups attached to the phenyl ring required longer reaction time for a complete conversion of the benzylic alcohols.

  20. A comparative study of silver-graphene oxide nanocomposites as a recyclable catalyst for the aerobic oxidation of benzyl alcohol: Support effect

    Energy Technology Data Exchange (ETDEWEB)

    Zahed, Bahareh; Hosseini-Monfared, Hassan, E-mail: monfared@znu.ac.ir

    2015-02-15

    Graphical abstract: - Highlights: • Characteristics of three different graphene oxide (GO) are studied as a support for Ag nanoparticles. • The required conditions for a best support are determined. • For the first time the silver nanoparticles decorated GO as catalyst for aerobic oxidation of benzyl alcohol and the effects of the degree of reduction of GO on AgNPs on GO are reported. - Abstract: Three different nanocomposites of silver and graphene oxide, namely silver nanoparticles (AgNPs) immobilized on reduced graphene oxide (AgNPs/rGO), partially reduced graphene oxide (AgNPs/GO) and thiolated partially reduced graphene oxide (AgNPs/GOSH), were synthesized in order to compare their properties. Characterizations were carried out by infrared and UV–Vis and Raman spectroscopy, ICP, X-ray diffraction, SEM and TEM, confirming both the targeted chemical modification and the composite formation. The nanocomposites were successfully employed in the aerobic oxidation of benzyl alcohol at atmospheric pressure. AgNPs/GOSH is stable and recyclable catalyst which showed the highest activity in the aerobic oxidation of benzyl alcohol in the presence of N-hydroxyphthalimide (NHPI) to give benzaldehyde with 58% selectivity in 24 h at 61% conversion. The favorite properties of AgNPs/GOSH are reasonably attributed to the stable and well distributed AgNPs over GOSH due to strong adhesion between AgNPs and GOSH.

  1. 40 CFR 721.10147 - Acrylate derivative of alkoxysilylalkane ester and mixed metal oxides (generic).

    Science.gov (United States)

    2010-07-01

    ... alkoxysilylalkane ester and mixed metal oxides (generic). 721.10147 Section 721.10147 Protection of Environment... alkoxysilylalkane ester and mixed metal oxides (generic). (a) Chemical substance and significant new uses subject to... ester and mixed metal oxides (PMN P-07-198) is subject to reporting under this section for...

  2. 40 CFR 721.5315 - Nickel, cobalt mixed metal oxide (generic).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Nickel, cobalt mixed metal oxide... Specific Chemical Substances § 721.5315 Nickel, cobalt mixed metal oxide (generic). (a) Chemical substance... nickel, cobalt mixed metal oxide. (PMN P-02-90) is subject to reporting under this section for the...

  3. Flexible Electronics Powered by Mixed Metal Oxide Thin Film Transistors

    Science.gov (United States)

    Marrs, Michael

    A low temperature amorphous oxide thin film transistor (TFT) and amorphous silicon PIN diode backplane technology for large area flexible digital x-ray detectors has been developed to create 7.9-in. diagonal backplanes. The critical steps in the evolution of the backplane process include the qualification and optimization of the low temperature (200 °C) metal oxide TFT and a-Si PIN photodiode process, the stability of the devices under forward and reverse bias stress, the transfer of the process to flexible plastic substrates, and the fabrication and assembly of the flexible detectors. Mixed oxide semiconductor TFTs on flexible plastic substrates suffer from performance and stability issues related to the maximum processing temperature limitation of the polymer. A novel device architecture based upon a dual active layer improves both the performance and stability. Devices are directly fabricated below 200 ºC on a polyethylene naphthalate (PEN) substrate using mixed metal oxides of either zinc indium oxide (ZIO) or indium gallium zinc oxide (IGZO) as the active semiconductor. The dual active layer architecture allows for adjustment to the saturation mobility and threshold voltage stability without the requirement of high temperature annealing, which is not compatible with flexible plastic substrates like PEN. The device performance and stability is strongly dependent upon the composition of the mixed metal oxide; this dependency provides a simple route to improving the threshold voltage stability and drive performance. By switching from a single to a dual active layer, the saturation mobility increases from 1.2 cm2/V-s to 18.0 cm2/V-s, while the rate of the threshold voltage shift decreases by an order of magnitude. This approach could assist in enabling the production of devices on flexible substrates using amorphous oxide semiconductors. Low temperature (200°C) processed amorphous silicon photodiodes were developed successfully by balancing the tradeoffs

  4. Properties of solid solutions, doped film, and nanocomposite structures based on zinc oxide

    Science.gov (United States)

    Lashkarev, G. V.; Shtepliuk, I. I.; Ievtushenko, A. I.; Khyzhun, O. Y.; Kartuzov, V. V.; Ovsiannikova, L. I.; Karpyna, V. A.; Myroniuk, D. V.; Khomyak, V. V.; Tkach, V. N.; Timofeeva, I. I.; Popovich, V. I.; Dranchuk, N. V.; Khranovskyy, V. D.; Demydiuk, P. V.

    2015-02-01

    A study of the properties of materials based on the wide bandgap zinc oxide semiconductor, which are promising for application in optoelectronics, photovoltaics and nanoplasmonics. The structural and optical properties of solid solution Zn1-xCdxO films with different cadmium content, are studied. The samples are grown using magnetron sputtering on sapphire backing. Low-temperature photoluminescence spectra revealed emission peaks associated with radiative recombination processes in those areas of the film that have varying amounts of cadmium. X-ray phase analysis showed the presence of a cadmium oxide cubic phase in these films. Theoretical studies of the solid solution thermodynamic properties allowed for a qualitative interpretation of the observed experimental phenomena. It is established that the growth of the homogeneous solid solution film is possible only at high temperatures, whereas regions of inhomogeneous composition can be narrowed through elastic deformation, caused by the mismatch of the film-backing lattice constants. The driving forces of the spinodal decomposition of the Zn1-xCdxO system are identified. Fullerene-like clusters of Znn-xCdxOn are used to calculate the bandgap and the cohesive energy of ZnCdO solid solutions. The properties of transparent conductive ZnO films, doped with Group III donor impurities (Al, Ga, In), are examined. It is shown that oxygen vacancies are responsible for the hole trap centers in the zinc oxide photoconductivity process. We also examine the photoluminescence properties of metal-ZnO nanocomposite structures, caused by surface plasmons.

  5. Mussel-Inspired Architecture of High-Flux Loose Nanofiltration Membrane Functionalized with Antibacterial Reduced Graphene Oxide-Copper Nanocomposites.

    Science.gov (United States)

    Zhu, Junyong; Wang, Jing; Uliana, Adam Andrew; Tian, Miaomiao; Zhang, Yiming; Zhang, Yatao; Volodin, Alexander; Simoens, Kenneth; Yuan, Shushan; Li, Jian; Lin, Jiuyang; Bernaerts, Kristel; Van der Bruggen, Bart

    2017-08-30

    Graphene-based nanocomposites have a vast potential for wide-ranging antibacterial applications due to the inherently strong biocidal activity and versatile compatibility of such nanocomposites. Therefore, graphene-based functional nanomaterials can introduce enhanced antibiofouling and antimicrobial properties to polymeric membrane surfaces. In this study, reduced graphene oxide-copper (rGOC) nanocomposites were synthesized as newly robust biocides via in situ reduction. Inspired by the emerging method of bridging ultrafiltration membrane surface cavities, loose nanofiltration (NF) membranes were designed using a rapid (2 h) bioinspired strategy in which rGOC nanocomposites were firmly codeposited with polydopamine (PDA) onto an ultrafiltration support. A series of analyses (SEM, EDS, XRD, XPS, TEM, and AFM) confirmed the successful synthesis of the rGO-Cu nanocomposites. The secure loading of rGOC composites onto the membrane surfaces was also confirmed by SEM and AFM images. Water contact angle results display a high surface hydrophilicity of the modified membranes. The PDA-rGOC functionalization layer facilitated a high water permeability (22.8 L m(-2) h(-1) bar(-1)). The PDA-rGOC modification additionally furnished the membrane with superior separation properties advantageous for various NF applications such as dye purification or desalination, as ultrahigh (99.4% for 0.5 g L(-1) reactive blue 2) dye retention and high salt permeation (7.4% for 1.0 g L(-1) Na2SO4, 2.5% for 1.0 g L(-1) NaCl) was achieved by the PDA-rGOC-modified membranes. Furthermore, after 3 h of contact with Escherichia coli (E. coli) bacteria, the rGOC-functionalized membranes exhibited a strong antibacterial performance with a 97.9% reduction in the number of live E. coli. This study highlights the use of rGOC composites for devising loose NF membranes with strong antibacterial and separation performance.

  6. Antimicrobial and Controlled Release Studies of a Novel Nystatin Conjugated Iron Oxide Nanocomposite

    Directory of Open Access Journals (Sweden)

    Samer Hasan Hussein-Al-Ali

    2014-01-01

    Full Text Available Nystatin is a tetraene diene polyene antibiotic showing a broad spectrum of antifungal activity. In the present study, we prepared a nystatin nanocomposite (Nyst-CS-MNP by loading nystatin (Nyst on chitosan (CS coated magnetic nanoparticles (MNPs. The magnetic nanocomposites were characterized by X-ray powder diffraction (XRD, Fourier transform infrared spectroscopy (FT-IR, thermogravimetry analysis (TGA, vibrating sample magnetometer (VSM, and scanning electron microscopy (SEM. The XRD results showed that the MNPs and nanocomposite are pure magnetite. The FTIR analysis confirmed the binding of CS on the surface of the MNPs and also the loading of Nyst in the nanocomposite. The Nyst drug loading was estimated using UV-Vis instrumentation and showing a 14.9% loading in the nanocomposite. The TEM size image of the MNPs, CS-MNP, and Nyst-CS-MNP was 13, 11, and 8 nm, respectively. The release profile of the Nyst drug from the nanocomposite followed a pseudo-second-order kinetic model. The antimicrobial activity of the as-synthesized Nyst and Nyst-CS-MNP nanocomposite was evaluated using an agar diffusion method and showed enhanced antifungal activity against Candida albicans. In this manner, this study introduces a novel nanocomposite that can decrease fungus activity on-demand for numerous medical applications.

  7. Preparation and characterization of carbon/nickel oxide nanocomposite coatings for solar absorber applications

    CSIR Research Space (South Africa)

    Roro, Kittessa T

    2012-04-01

    Full Text Available Nanocomposite materials have wide range of applications in solar energy conversion. In this work, C/NiO nanocomposite solar energy absorbing surfaces were prepared using sol-gel synthesis and deposited on aluminium substrates using a spin coater...

  8. Evolution of microstructure, strain and physical properties in oxide nanocomposite films.

    Science.gov (United States)

    Chen, Aiping; Weigand, Marcus; Bi, Zhenxing; Zhang, Wenrui; Lü, Xuejie; Dowden, Paul; MacManus-Driscoll, Judith L; Wang, Haiyan; Jia, Quanxi

    2014-06-24

    We, using LSMO:ZnO nanocomposite films as a model system, have studied the effect of film thickness on the physical properties of nanocomposites. It shows that strain, microstructure, as well as magnetoresistance strongly rely on film thickness. The magnetotransport properties have been fitted by a modified parallel connection channel model, which is in agreement with the microstructure evolution as a function of film thickness in nanocomposite films on sapphire substrates. The strain analysis indicates that the variation of physical properties in nanocomposite films on LAO is dominated by strain effect. These results confirm the critical role of film thickness on microstructures, strain states, and functionalities. It further shows that one can use film thickness as a key parameter to design nanocomposites with optimum functionalities.

  9. Modified hydrothermal synthesis and characterization of reduced graphene oxide-silver selenide nanocomposites with enhanced reactive oxygen species generation

    Institute of Scientific and Technical Information of China (English)

    Lei Zhu; Shu Ye; Asghar Ali; Kefayat Ulla; Kwang Youn Cho; Won-Chun Oh

    2015-01-01

    A visible‐light photocatalyst containing Ag2Se and reduced graphene oxide (RGO) was synthesized by a facile sonochemical‐assisted hydrothermal method. X‐ray diffraction, scanning electron mi‐croscopy with energy‐dispersive X‐ray analysis, and ultraviolet‐visible diffuse reflectance spectros‐copy results indicated that the RGO‐Ag2Se nanocomposite contained small crystalline Ag2Se nano‐particles dispersed over graphene nanosheets and absorbed visible light. The high crystallinity of the nanoparticles increased photocatalytic activity by facilitating charge transport. N2 adsorp‐tion‐desorption measurements revealed that the RGO‐Ag2Se nanocomposite contained numerous pores with an average diameter of 9 nm, which should allow reactant molecules to readily access the Ag2Se nanoparticles. The RGO‐Ag2Se nanocomposite exhibited higher photocatalytic activity than bulk Ag2Se nanoparticles to degrade organic pollutant rhodamine B and industrial dye Texbrite BA‐L under visible‐light irradiation (λ>420 nm). The generation of reactive oxygen spe‐cies in RGO‐Ag2Se was evaluated through its ability to oxidize 1,5‐diphenylcarbazide to 1,5‐diphenylcarbazone. The small size of the Ag2Se nanoparticles in RGO‐Ag2Se was related to the use of ultrasonication during their formation, revealing that this approach is attractive to form po‐rous RGO‐Ag2Se materials with high photocatalytic activity under visible light.

  10. One-step sonochemical synthesis of a graphene oxide-manganese oxide nanocomposite for catalytic glycolysis of poly(ethylene terephthalate).

    Science.gov (United States)

    Park, Gle; Bartolome, Leian; Lee, Kyoung G; Lee, Seok Jae; Kim, Do Hyun; Park, Tae Jung

    2012-07-07

    Ultrasound-assisted synthesis of a graphene oxide (GO)-manganese oxide nanocomposite (GO-Mn(3)O(4)) was conducted without further modification of GO or employing secondary materials. With the GO nanoplate as a support, potassium permanganate oxidizes the carbon atoms in the GO support and gets reduced to Mn(3)O(4). An intensive ultrasound method could reduce the number of reaction steps and temperature, enhance the reaction rate and furthermore achieve a Mn(3)O(4) phase. The composite was characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). The coverage and crystallinity of Mn(3)O(4) were controlled by changing the ratio of permanganate to GO dispersion. The synthesized nanocomposite was used as a catalyst for poly(ethylene terephthalate) (PET) depolymerization into its monomer, bis(2-hydroxylethyl) terephthalate (BHET). The highest monomer yield of 96.4% was obtained with the nanocomposite containing the lowest amount of Mn(3)O(4), while PET glycolysis with the Mn(3)O(4) without GO yielded 82.7% BHET.

  11. Direct chemical oxidation of mixed or toxic wastes

    Energy Technology Data Exchange (ETDEWEB)

    Balazs, G B; Cooper, J F; Farmer, J C; Lewis, P

    1999-05-01

    Direct Chemical Oxidation (DCO) is an ambient-pressure, low-temperature (<100 C), and aqueous-based process for general-purpose destruction of the organic fraction of hazardous or mixed waste. It uses the peroxydisulfate anion (S{sub 2}O{sub 8}{sup 2{minus}}) in acid or base solutions. The byproduct of the oxidation reaction, typically sodium or ammonium hydrogen sulfate, may be recycled electrolytically to produce the oxidant. The oxidation kinetic reaction is first order with respect to the peroxydisulfate concentration, expressed in equivalents. The rate constant is constant for nearly all dissolved organic compounds: k{sub a} = 0.01 {+-} 0.005 min{sup {minus}1}. This reflects a common rate-determining step, which is the decomposition of the peroxydisulfate anion into the chemically active derivative, the sulfate radical anion, SO{sub 4}{sup {minus}}. This decomposition is promoted in DCO by raising the operating temperature into the range of 80-100 C. Rates are given for approximately 30 substances with diverse functional groups at low concentrations, and for a number of solid and liquid wastes typical of nuclear and chemical industries. The process has been scale up for treatment studies on chlorinated hydrocarbons, in which the hydrolysis of solvent mixtures was followed by oxidation of products in a series of stirred tank reactors. Cost estimates, safety considerations, and a comprehensive bibliography are given.

  12. In vitro and in vivo evaluation of a new nanocomposite, containing high density polyethylene, tricalcium phosphate, hydroxyapatite, and magnesium oxide nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Pourdanesh, Fereydoun [Dental Research Center, Research Institute of Dental Sciences, Shahid Beheshti University of Medical Sciences, Tehran 8916733754 (Iran, Islamic Republic of); Jebali, Ali, E-mail: alijebal2011@gmail.com [Department of Medical Physics and Biomedical Engineering, Shahid Beheshti University of Medical Sciences, Tehran (Iran, Islamic Republic of); Hekmatimoghaddam, Seyedhossein [Department of Laboratory Sciences, School of Paramedicine, Shahid Sadoughi University of Medical Sciences, Yazd (Iran, Islamic Republic of); Allaveisie, Azra [Department of Genetics, Research and Clinical Center for Infertility, Shahid Sadoughi University of Medical Sciences, Yazd (Iran, Islamic Republic of)

    2014-07-01

    In this study, a new nanocomposite, which contained high density polyethylene (HDPE), tricalcium phosphate (Ca{sub 3}(PO{sub 4}){sub 2}) nanoparticles (TCP NPs), hydroxyapatite nanoparticles (HA NPs), and magnesium oxide nanoparticles (MgO NPs) was prepared. As in vitro experiment, human osteoblasts (HOB) cells were exposed to pristine HDPE and its nanocomposite for a period of 1, 4, and 7 days at 37 °C, and then different assays were carried out, including osteoblast cell proliferation, Trypan blue staining, cell viability, alkaline phosphatase (ALP), and cell adhesion. Antibacterial property of pristine HDPE and its nanocomposite was evaluated, and also their mechanical properties were measured after 2 and 4 months. As in vivo experiment, pristine HDPE and its nanocomposite were separately implanted on calvarium bone of rabbits, and tissue inflammation and osteogenesis were investigated after 2, 4, and 6 months. In case of HOB cells treated with HDPE or nanocomposite, as incubation time was increased, cell proliferation, live/dead ratio, and cell viability were decreased. But, the ALP activity and cell adhesion of HOB cells which treated with nanocomposite were raised after increase of incubation time. This study demonstrated that although the mechanical properties of nanocomposite were similar to HDPE sheet, but their antibacterial property was not similar. The in vivo experiment showed that both pristine HDPE and its nanocomposite had same inflammation responses. Interestingly, osteogenesis was observed after 2 months at bone/nanocomposite interface, and was highly increased after 4 and 6 months. It must be noted that such pattern was not seen at bone/HDPE interface. - Highlights: • The effect of various nanoparticles like as Ca{sub 3}(PO{sub 4}){sub 2}, hydroxyapatite, and MgO was studied. • HDPE/TCP/HA/MgO nanocomposite was biocompatible. • The effect of nanoparticles showed high antibacterial property.

  13. High electrocatalytic performance of nitrogen-doped carbon nanofiber-supported nickel oxide nanocomposite for methanol oxidation in alkaline medium

    Science.gov (United States)

    Al-Enizi, Abdullah M.; Elzatahry, Ahmed A.; Abdullah, Aboubakr M.; Vinu, Ajayan; Iwai, Hideo; Al-Deyab, Salem S.

    2017-04-01

    Nitrogen-Doped Carbon Nanofiber (N-CNF)-supported NiO composite was prepared by electrospinning a sol-gel mixture of graphene and polyaniline (PANi) with aqueous solutions of Polyvinylpyrrolidone (PVP) followed by a high-temperature annealing process. The electrospun was stabilized for 2 h at 280 °C, carbonized for 5 h at 1200 °C then loaded by 10% NiO. The electrocatalytic activities of the produced nanocomposite have been studied using cyclic voltammetry, and chronoamperometry. Also, N-CNF was characterized by X-ray diffraction (XRD), thermogravimetric analysis (TGA), surface area (BET), X-ray photoelectron spectroscopy (XPS), transmission electron microscope (TEM), and scanning-electron microscopy (SEM). The obtained N-doped carbon nanofiber was found to have a nitrogen content of 2.6 atomic% with a diameter range of (140-160) nm, and a surface area (393.3 m2 g-1). In addition, it showed a high electrocatalytic behavior towards methanol oxidation reaction in alkaline medium and high stability and resistivity to the adsorption of intermediates.

  14. A facile synthesis of zinc oxide/multiwalled carbon nanotube nanocomposite lithium ion battery anodes by sol-gel method

    Science.gov (United States)

    Köse, Hilal; Karaal, Şeyma; Aydın, Ali Osman; Akbulut, Hatem

    2015-11-01

    Free standing zinc oxide (ZnO) and multiwalled carbon nanotube (MWCNT) nanocomposite materials are prepared by a sol gel technique giving a new high capacity anode material for lithium ion batteries. Free-standing ZnO/MWCNT nanocomposite anodes with two different chelating agent additives, triethanolamine (TEA) and glycerin (GLY), yield different electrochemical performances. Field emission gun scanning electron microscopy (FEG-SEM), energy dispersive X-ray spectrometer (EDS), high resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD) analyses reveal the produced anode electrodes exhibit a unique structure of ZnO coating on the MWCNT surfaces. Li-ion cell assembly using a ZnO/MWCNT/GLY free-standing anode and Li metal cathode possesses the best discharge capacity, remaining as high as 460 mAh g-1 after 100 cycles. This core-shell structured anode can offer increased energy storage and performance over conventional anodes in Li-ion batteries.

  15. Fabrication of a Biomass-Based Hydrous Zirconium Oxide Nanocomposite for Preferable Phosphate Removal and Recovery.

    Science.gov (United States)

    Qiu, Hui; Liang, Chen; Zhang, Xiaolin; Chen, Mindong; Zhao, Yunxia; Tao, Tao; Xu, Zhengwen; Liu, Gang

    2015-09-23

    Advanced removal of phosphate by low-cost adsorbents from municipal wastewater or industrial effluents is an effective and economic way to prevent the occurrence of eutrophication. Here, we proposed a novel method to immobilize hydrous zirconium oxide nanoparticle within quaternary-aminated wheat straw, and obtained an inexpensive, eco-friendly nanocomposite Ws-N-Zr. The biomass-based Ws-N-Zr exhibited higher preference toward phosphate than commercial anion exchanger IRA-900 when competing sulfate ions coexisted at relatively high levels. Such excellent performance of Ws-N-Zr resulted from its specific hybrid structure, the quaternary ammonium groups bonded on the host favor the preconcentration of phosphate ions inside the wheat straw based on Donnan effect, and the encapsulated HZO nanoparticle exhibits preferable sequestration of phosphate ions through specific interaction, as further demonstrated by FTIR and X-ray photoelectron spectroscopy. Cycle adsorption and regeneration experiments demonstrated that Ws-N-Zr could be employed for repeated use without significant capacity loss, when the binary NaOH-NaCl solution was employed as the regenerant. The influence of solution pH and contact time was also examined. The results suggested that Ws-N-Zr has a great potential in efficient removal of phosphate in contaminated waters.

  16. Magnetite/graphene oxide nano-composite for enhancement of hydrogen production from gelatinaceous wastewater.

    Science.gov (United States)

    Mostafa, Alsayed; El-Dissouky, Ali; Fawzy, Amal; Farghaly, Ahmed; Peu, Pascal; Dabert, Patrick; Le Roux, Sophie; Tawfik, Ahmed

    2016-09-01

    The effect of substrate to inoculum (So/Xo) ratio and supplementation of magnetite/graphene oxide (MGO) nano-composite material on hydrogen production from gelatinaceous wastewater via dark fermentation process was investigated. Results demonstrated that optimum So/Xo ratio of 1.0gCOD/gVSS achieved maximal hydrogen yield (HY) of 79.2±11.9mL H2/gCOD removed. Supplementation of anaerobes with 100mg/L MGO promoted HY up to 112.4±10.5mL H2/gCOD removed. Moreover, the degradation efficiency of carbohydrates, proteins and lipids was improved to 80.8±7.6, 34.4±2.3 and 31.4±2.2%, respectively. Acetate (HAc) and butyrate (HBu) concentrations increased from 102±6.8 to 125.3±6.3 and from 31.1±1.5 to 48.8±3.5mg/gVSS, respectively. However, propionate (HPr) concentration dropped from 35.9±2.7 to 15±1.3mg/gVSS. Hydrogenase enzyme activity increased 9-folds and the anaerobes elongated from ca. 1.8-2.9 to ca. 2.5-5.1μm with MGO addition. Moreover, Proteobacteria, Firmicutes, Clostridia and Bacilli were detected with the batches supplemented with MGO.

  17. Fullerenol/doxorubicin nanocomposite mitigates acute oxidative stress and modulates apoptosis in myocardial tissue

    Science.gov (United States)

    Seke, Mariana; Petrovic, Danijela; Djordjevic, Aleksandar; Jovic, Danica; Labudovic Borovic, Milica; Kanacki, Zdenko; Jankovic, Milan

    2016-12-01

    Fullerenol (C60(OH)24) is present in aqueous solutions in the form of polyanion nanoparticles with particles’ size distribution within the range from 15 to 42 nm. In this research it is assumed that these features could enable fullerenol nanoparticles (FNPs) to bind positively charged molecules like doxorubicin (DOX) and serve as drug carriers. Considering this, fullerenol/doxorubicin nanocomposite (FNP/DOX) is formed and characterized by ultra-performance liquid chromatography tandem mass spectrometry, dynamic light scattering, atomic force microscopy and transmission electron microscopy. Measurements have shown that DOX did not significantly affect particle size (23 nm). It is also assumed that FNP/DOX could reduce the acute cardiotoxic effects of DOX in vivo (Wistar rats treated i.p.). In this study, quantitative real time polymerase chain reaction results have shown that treatment with DOX alone caused significant increase in mRNA levels of catalase (p cell resistance to apoptosis. Moreover, ultrastructural analysis has shown the absence of myelin figures within the mitochondria in the heart tissue with FNP/DOX treatment, indicating reduction of oxidative stress. Hence, our results have implied that FNP/DOX is generally less harmful to the heart compared to DOX.

  18. Simultaneous Reduction and Functionalization of Graphene Oxide by 4-Hydrazinobenzenesulfonic Acid for Polymer Nanocomposites

    Directory of Open Access Journals (Sweden)

    Song-Jie Qiao

    2016-02-01

    Full Text Available Graphene oxide (GO was functionalized and reduced simultaneously by a new reductant, 4-hydrazinobenzenesulfonic acid (HBS, with a one-step and environmentally friendly process. The hydrophilic sulfonic acid group in HBS was grafted onto the surface of GO through a covalent bond. The successful preparation of HBS reduced GO (HBS-rGO was testified by scanning electron microscope (SEM, X-ray diffraction (XRD, Raman spectroscopy, Fourier transform infrared spectra (FTIR, X-ray photoelectron spectroscopic (XPS and thermogravimetric analysis (TGA. The interlayer space of HBS-rGO was increased to 1.478 nm from 0.751 nm for GO, resulting in a subdued Van der Waals’ force between layers and less possibility to form aggregations. The aqueous dispersibility of graphene was improved to 13.49 mg/mL from 0.58 mg/mL after the functionalization. The viscosity of the epoxy resin based HBS-rGO composite could be regulated by an adjustment of the content of HBS-rGO. This study provides a new and applicable approach for the preparation of hydrophilic functionalized graphene, and makes it possible for the application of graphene in some functional polymer nanocomposites, such as specialty water-based coatings.

  19. Synthesis of Oxide Nanoparticles in Hybrid Nanocomposite Coatings as Nanoreservoirs of Corrosion Inhibitors

    Science.gov (United States)

    Pirhady Tavandashti, Nahid; Sanjabi, Sohrab

    Nanostructured hybrid silica/epoxy films containing boehmite nanoparticles were investigated in the present work as pretreatments for AA2024 alloy. To produce the nanocomposite sol-gel films, boehmite nanoparticles prepared from hydrolysis/condensation of aluminum isopropoxide (AlI) were doped into another hybrid organosiloxane sol. The produced oxide nanoparticles have the capability to act as nanoreservoirs of corrosion inhibitors, releasing them controllably to protect the metallic substrate from corrosion. For this purpose the corrosion inhibitor, cerium nitrate, was introduced into the sol-gel system via loading the nanoparticles. The morphology and the structure of the hybrid sol-gel films were studied by Scanning Electron Microscopy (SEM). The corrosion protection properties of the films were investigated by Potentiodynamic Scanning (PDS) and Electrochemical Impedance Spectroscopy (EIS). The results show that the presence of boehmite nanoparticles highly improved the corrosion protection performance of the silica/epoxy coatings. Moreover, they can act as nanoreservoirs of corrosion inhibitors and provide prolonged release of cerium ions, offering a self-healing property to the film.

  20. Reduced-mobility layers with high internal mobility in poly(ethylene oxide)-silica nanocomposites

    Science.gov (United States)

    Golitsyn, Yury; Schneider, Gerald J.; Saalwächter, Kay

    2017-05-01

    A series of poly(ethylene oxide) nanocomposites with spherical silica was studied by proton NMR spectroscopy, identifying and characterizing reduced-mobility components arising from either room-temperature lateral adsorption or possibly end-group mediated high-temperature bonding to the silica surface. The study complements earlier neutron-scattering results for some of the samples. The estimated thickness of a layer characterized by significant internal mobility resembling backbone rotation ranges from 2 nm for longer (20 k) chains adsorbed on 42 nm diameter particles to 0.5 nm and below for shorter (2 k) chains on 13 nm particles. In the latter case, even lower adsorbed amounts are found when hydroxy endgroups are replaced by methyl endgroups. Both heating and water addition do not lead to significant changes of the observables, in contrast to other systems such as acrylate polymers adsorbed to silica, where temperature- and solvent-induced softening associated with a glass transition temperature gradient was evidenced. We highlight the actual agreement and complementarity of NMR and neutron scattering results, with the earlier ambiguities mainly arising from different sensitivities to the component fractions and the details of their mobility.

  1. Mutual solubility of scandium oxide-hematite magnetic nanocomposites: Mössbauer spectroscopy investigation

    Science.gov (United States)

    Allwes, Mark; Mekaoui, Mehdi; Sorescu, Monica

    2017-08-01

    xSc2O3-(1-x)α-Fe2O3 (x = 0.1, 0.3 and 0.5) nanocomposite systems were successfully synthesized by mechanochemical activation of Sc2O3 and α-Fe2O3 mixtures for 0-12 h of ball milling time. Mössbauer investigations were performed to study the structural and magnetic properties of xSc2O3-(1-x)α-Fe2O3 nanoparticle systems during the mechanochemical activation treatment. The Mössbauer studies showed that the spectrum of the mechanochemically activated composites evolved from a sextet for hematite to sextets and a doublet upon duration of the milling process with scandium oxide. Mutual solubility was achieved at the nanoscopic level only. A comprehensive Mössbauer study was performed by recording the recoilless fraction f as function of the ball milling time using our dual absorber method. The results obtained indicate that prolonged ball milling times favor formation of the Fe:Sc2O3 non-magnetic phase and decrease of the grain sizes for both magnetic and non-magnetic components, leading to a maximum in the recoilless fraction followed by its decay.

  2. DEVELOPMENT OF THIN FILM NANOCOMPOSITE EMBEDDED WITH GRAPHENE OXIDE FOR MgSO4 REMOVAL

    Directory of Open Access Journals (Sweden)

    I. WAN AZELEE

    2016-07-01

    Full Text Available Thin film nanocomposite (TFN membrane with graphene oxide (GO embedded into the polyamide (PA selective top layer has been developed for salt removal. 0.1 wt% of GO were dispersed in the trimesoyl chloride (TMC organic solution and incorporated into the PA layer during interfacial polymerization with piperazine. The fabricated TFN membrane was characterized in terms of the membrane morphological structure and surface hydrophilicity. The divalent magnesium sulfate (MgSO4 salt removal performance of the TFN was evaluated and compared with the thin film composite (TFC counterpart. The surface morphology of the TFN membranes was altered and the surface hydrophilicity was increased with the presence of GO. The incorporation of GO has improved the permeate water flux, in which maximum improvement of 140% compared to that of TFC has been obtained, without sacrificing much on the salt rejection properties. Although further investigation is required, this study has experimentally verified the potential application of GO to heighten the salt separation performance of TFN membranes.

  3. Fullerenol/doxorubicin nanocomposite mitigates acute oxidative stress and modulates apoptosis in myocardial tissue.

    Science.gov (United States)

    Seke, Mariana; Petrovic, Danijela; Djordjevic, Aleksandar; Jovic, Danica; Borovic, Milica Labudovic; Kanacki, Zdenko; Jankovic, Milan

    2016-12-02

    Fullerenol (C60(OH)24) is present in aqueous solutions in the form of polyanion nanoparticles with particles' size distribution within the range from 15 to 42 nm. In this research it is assumed that these features could enable fullerenol nanoparticles (FNPs) to bind positively charged molecules like doxorubicin (DOX) and serve as drug carriers. Considering this, fullerenol/doxorubicin nanocomposite (FNP/DOX) is formed and characterized by ultra-performance liquid chromatography tandem mass spectrometry, dynamic light scattering, atomic force microscopy and transmission electron microscopy. Measurements have shown that DOX did not significantly affect particle size (23 nm). It is also assumed that FNP/DOX could reduce the acute cardiotoxic effects of DOX in vivo (Wistar rats treated i.p.). In this study, quantitative real time polymerase chain reaction results have shown that treatment with DOX alone caused significant increase in mRNA levels of catalase (p FNP/DOX (p FNP/DOX was applied, suggesting cell resistance to apoptosis. Moreover, ultrastructural analysis has shown the absence of myelin figures within the mitochondria in the heart tissue with FNP/DOX treatment, indicating reduction of oxidative stress. Hence, our results have implied that FNP/DOX is generally less harmful to the heart compared to DOX.

  4. Nanocomposites of graphene oxide and upconversion rare-earth nanocrystals with superior optical limiting performance

    KAUST Repository

    Wei, Wei

    2012-04-20

    Upconversion rare-earth nanomaterials (URENs) possess highly efficient near-infrared (NIR), e.g., 980 nm, laser absorption and unique energy upconversion capabilities. On the other hand, graphene and its derivatives, such as graphene oxide (GO), show excellent performance in optical limiting (OL); however, the wavelengths of currently used lasers for OL studies mainly focus on either 532 or 1064 nm. To design new-generation OL materials working at other optical regions, such as the NIR, a novel nanocomposites, GO-URENs, which combines the advantages of both its components, is synthesized by a one-step chemical reaction. Transmission electron microscopy, X-ray diffraction, infrared spectroscopy, and fluorescence studies prove that the α-phase URENs uniformly attach on the GO surface via covalent chemical bonding, which assures highly efficient energy transfer between URENs and GO, and also accounts for the significantly improved OL performance compared to either GO or URENs. The superior OL effect is also observed in the proof-of-concept thin-film product, suggesting immediate applications in making high-performance laser-protecting products and optoelectronic devices. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Fabrication and mechanical evaluation of hydroxyapatite/oxide nano-composite materials.

    Science.gov (United States)

    Mohamed, Khaled R; Beherei, Hanan H; El Bassyouni, Gehan T; El Mahallawy, Nahed

    2013-10-01

    In the current study, the semiconducting metal oxides such as nano-ZnO and SiO2 powders were prepared via sol-gel technique and conducted on nano-hydroxyapatite (nHA) which was synthesized by chemical precipitation. The properties of fabricated nano-structured composites containing different ratios of HA, ZnO and SiO2 were examined using X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscope (SEM) and transmission electron microscope (TEM) techniques. The effect of the variation of ratios between the three components on mechanical, microstructure and in-vitro properties was assessed to explore the possibility of enhancing these properties. The results proved that the mechanical properties exhibited an increment with increasing the ZnO content at the extent of HA. In-vitro study proved the formation and nucleation of apatite onto the surface of the fabricated composites after one week of immersion. It is concluded that HA composites containing SiO2 or SiO2/ZnO content had a suitable mechanical properties and ability to form apatite particles onto the composite surface. Based on bioactivity behavior, Si-HA is more bioactive than pure hydroxyapatite and nano-arrangements will provide an interface for better bone formation. Therefore, these nano-composites will be promising as bone substitutes especially in load bearing sites.

  6. Facile synthesis of manganese ferrite/graphene oxide nanocomposites for controlled targeted drug delivery

    Science.gov (United States)

    Wang, Guangshuo; Ma, Yingying; Zhang, Lina; Mu, Jingbo; Zhang, Zhixiao; Zhang, Xiaoliang; Che, Hongwei; Bai, Yongmei; Hou, Junxian

    2016-03-01

    In this study, manganese ferrite/graphene oxide (MnFe2O4/GO) nanocomposites as controlled targeted drug delivery were prepared by a facile sonochemical method. It was found that GO nanosheets were fully exfoliated and decorated with MnFe2O4 nanoparticles having diameters of 5-13 nm. The field-dependent magnetization curve indicated superparamagnetic behavior of the obtained MnFe2O4/GO with saturation magnetization of 34.9 emu/g at room temperature. The in vitro cytotoxicity testing exhibited negligible cytotoxicity of as-prepared MnFe2O4/GO even at the concentration as high as 150 μg/mL. Doxorubicin hydrochloride (DOX) as an anti-tumor model drug was utilized to explore the application potential of MnFe2O4/GO for controlled drug delivery. The drug loading capacity of this nanocarrier was as high as 0.97 mg/mg and the drug release behavior showed a sustained and pH-responsive way.

  7. Mixed protonic and electronic conductors hybrid oxide synaptic transistors

    Science.gov (United States)

    Fu, Yang Ming; Zhu, Li Qiang; Wen, Juan; Xiao, Hui; Liu, Rui

    2017-05-01

    Mixed ionic and electronic conductor hybrid devices have attracted widespread attention in the field of brain-inspired neuromorphic systems. Here, mixed protonic and electronic conductor (MPEC) hybrid indium-tungsten-oxide (IWO) synaptic transistors gated by nanogranular phosphorosilicate glass (PSG) based electrolytes were obtained. Unique field-configurable proton self-modulation behaviors were observed on the MPEC hybrid transistor with extremely strong interfacial electric-double-layer effects. Temporally coupled synaptic plasticities were demonstrated on the MPEC hybrid IWO synaptic transistor, including depolarization/hyperpolarization, synaptic facilitation and depression, facilitation-stead/depression-stead behaviors, spiking rate dependent plasticity, and high-pass/low-pass synaptic filtering behaviors. MPEC hybrid synaptic transistors may find potential applications in neuron-inspired platforms.

  8. Attapulgite-CeO{sub 2}/MoS{sub 2} ternary nanocomposite for photocatalytic oxidative desulfurization

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xiazhang, E-mail: lixiazhang509@163.com [Jiangsu Key Laboratory of Advanced Catalytic Materials and Technology, School of Petrochemical Engineering, Changzhou University, Changzhou 213164 (China); Jiangsu Key Laboratory for Environment Functional Materials, Suzhou University of Science and Technology, Suzhou 215009 (China); W.M.Keck Center for Advanced Microscopy and Microanalysis, University of Delaware, Newark, DE 19716 (United States); Zhang, Zuosong [School of Materials Science and Engineering, Changzhou University, Changzhou 213164 (China); Yao, Chao [Jiangsu Key Laboratory of Advanced Catalytic Materials and Technology, School of Petrochemical Engineering, Changzhou University, Changzhou 213164 (China); Lu, Xiaowang [School of Materials Science and Engineering, Changzhou University, Changzhou 213164 (China); Zhao, Xiaobing [School of Materials Science and Engineering, Changzhou University, Changzhou 213164 (China); Jiangsu Key Laboratory for Environment Functional Materials, Suzhou University of Science and Technology, Suzhou 215009 (China); Ni, Chaoying [W.M.Keck Center for Advanced Microscopy and Microanalysis, University of Delaware, Newark, DE 19716 (United States)

    2016-02-28

    Graphical abstract: - Highlights: • Novel attapulgite(ATP)-CeO{sub 2}/MoS{sub 2} ternary nanocomposites were fabricated. • ATP possessed outstanding adsorption property and enhanced the stability of the network structure. • CeO{sub 2}/MoS{sub 2} couples facilitated the separation of photo-induced electrons and holes. • Mass ratio of CeO{sub 2}/MoS{sub 2} influenced the photocatalytic oxidation desulfurization. - Abstract: Novel attapulgite(ATP)-CeO{sub 2}/MoS{sub 2} ternary nanocomposites were synthesized by microwave assisted assembly method. The structures of the nanocomposites were characterized by XRD, FT-IR, UV–vis, XPS and in situ TEM. The photocatalytic activities of ATP-CeO{sub 2}/MoS{sub 2} composites were investigated by degradating dibenzothiophene (DBT) in gasoline under visible light irradiation. The effect of the mass ratio of CeO{sub 2} to MoS{sub 2} on photocatalytic activity was investigated. The results indicate that the three-dimensional network structure is firmly constructed by ATP skeleton, CeO{sub 2} particles and MoS{sub 2} nanosheet which effectively increase the surface area of the composites and promote the separation of electrons and holes by resulting electronic transmission channels of multi-channel in space. The degradation rate of DBT can reach 95% under 3 h irradiation when the mass ratio of CeO{sub 2}/MoS{sub 2} is 4/10. A plausible mechanism for the photocatalytic oxidative desulfurization of this nanocomposite is put forward.

  9. Fabrication of highly catalytic silver nanoclusters/graphene oxide nanocomposite as nanotag for sensitive electrochemical immunoassay

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jiamian; Wang, Xiuyun; Wu, Shuo, E-mail: wushuo@dlut.edu.cn; Song, Jie; Zhao, Yanqiu; Ge, Yanqiu; Meng, Changgong

    2016-02-04

    Silver nanoclusters and graphene oxide nanocomposite (AgNCs/GRO) is synthesized and functionalized with detection antibody for highly sensitive electrochemical sensing of carcinoembryonic antigen (CEA), a model tumor marker involved in many cancers. AgNCs with large surface area and abundant amount of low-coordinated sites are synthesized with DNA as template and exhibit high catalytic activity towards the electrochemical reduction of H{sub 2}O{sub 2}. GRO is employed to assemble with AgNCs because it has large specific surface area, super electronic conductivity and strong π-π stacking interaction with the hydrophobic bases of DNA, which can further improve the catalytic ability of the AgNCs. Using AgNCs/GRO as signal amplification tag, an enzyme-free electrochemical immunosensing protocol is designed for the highly sensitive detection of CEA on the capture antibody functionalized immunosensing interface. Under optimal conditions, the designed immunosensor exhibits a wide linear range from 0.1 pg mL{sup −1} to 100 ng mL{sup −1} and a low limit of detection of 0.037 pg mL{sup −1}. Practical sample analysis reveals the sensor has good accuracy and reproducibility, indicating the great application prospective of the AgNCs/GRO in fabricating highly sensitive immunosensors, which can be extended to the detection of various kinds of low abundance disease related proteins. - Highlights: • An enzyme-free electrochemical immunosensor is reported for detecting proteins. • A silver nanocluster/graphene oxide composite is synthesized as nanotag. • The nanotags exhibit highly catalytic activity to the electro-reduction of H{sub 2}O{sub 2}. • The as-fabricated immunosensor could detect protein in serum samples.

  10. Facile synthesis of manganese ferrite/graphene oxide nanocomposites for controlled targeted drug delivery

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Guangshuo, E-mail: wgs8136@163.com; Ma, Yingying; Zhang, Lina; Mu, Jingbo; Zhang, Zhixiao; Zhang, Xiaoliang; Che, Hongwei; Bai, Yongmei; Hou, Junxian

    2016-03-01

    In this study, manganese ferrite/graphene oxide (MnFe{sub 2}O{sub 4}/GO) nanocomposites as controlled targeted drug delivery were prepared by a facile sonochemical method. It was found that GO nanosheets were fully exfoliated and decorated with MnFe{sub 2}O{sub 4} nanoparticles having diameters of 5–13 nm. The field-dependent magnetization curve indicated superparamagnetic behavior of the obtained MnFe{sub 2}O{sub 4}/GO with saturation magnetization of 34.9 emu/g at room temperature. The in vitro cytotoxicity testing exhibited negligible cytotoxicity of as-prepared MnFe{sub 2}O{sub 4}/GO even at the concentration as high as 150 μg/mL. Doxorubicin hydrochloride (DOX) as an anti-tumor model drug was utilized to explore the application potential of MnFe{sub 2}O{sub 4}/GO for controlled drug delivery. The drug loading capacity of this nanocarrier was as high as 0.97 mg/mg and the drug release behavior showed a sustained and pH-responsive way. - Highlights: • Manganese ferrite/graphene oxide (MnFe{sub 2}O{sub 4}/GO) were prepared by a facile sonochemical method. • GO nanosheets were fully exfoliated and decorated homogeneously with MnFe{sub 2}O{sub 4} nanoparticles. • MnFe{sub 2}O{sub 4}/GO exhibited superparamagnetic behavior with saturation magnetization of 34.9 emu/g. • The in vitro cytotoxicity testing showed negligible cytotoxicity of the obtained MnFe{sub 2}O{sub 4}/GO. • Drug loading capacity was as high as 0.97 mg/mg and drug release showed pH-sensitive feature.

  11. Synthesis and characterization of mixed melilite-type oxides

    Science.gov (United States)

    Granata, V.; Ubaldini, A.; Fittipaldi, R.; Rocco, L.; Pace, S.; Vecchione, A.

    2017-01-01

    The melilite-type oxides are potential targets for exploring interesting magnetic and electronic properties as well as multiferroicity and magnetoelectric effects. Polycrystalline samples of Ba2Cu1-xMnxGe2O7 have been synthesized by solid state reaction method. The morphology and chemical composition of the samples have been investigated by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). By using powder X-ray diffraction, the phase composition of the synthesized compounds and the evolution of their crystallographic axes as a function of the doping have been systematically studied. The synthesis of the polycrystalline compounds reported in this work is a prerequisite for the growth of high quality single crystals of mixed melilite-type oxides essential for the investigations of the complex magnetic phase diagram of these non-centrosymmetric systems.

  12. Ceria doped mixed metal oxide nanoparticles as oxidation catalysts: Synthesis and their characterization

    Directory of Open Access Journals (Sweden)

    S.S.P. Sultana

    2015-11-01

    Full Text Available Mixed metal nanoparticles (NPs have attracted significant attention as catalysts for various organic transformations. In this study, we have demonstrated the preparation of nickel–manganese mixed metal oxide NPs doped with X% nano cerium oxide (X = 1, 3, 5 mol% by a facile co-precipitation technique using surfactant and surfactant free methodologies. The as-synthesized materials were calcined at different temperatures (300 °C, 400 °C, and 500 °C, and were characterized using various spectroscopic techniques, including, FTIR and XRD. SEM analysis, TEM analysis and TGA were employed to evaluate the structural properties of the as-prepared catalyst. These were evaluated for their catalytic behaviour towards the conversion of benzyl alcohol to benzaldehyde, which was used as a model reaction with molecular oxygen as oxidant. Furthermore, the effect of the variation of the percentage of nano ceria doping and the calcination temperature on the performance of as-prepared mixed metal catalysts was also evaluated. The kinetic studies of the reactions performed employing gas chromatographic technique have revealed that the mixed metal oxide catalyst doped with 5% nano ceria displayed excellent catalytc activity, among various catalysts synthesized.

  13. Temperature dependence of dc electrical conductivity of activated carbon-metal oxide nanocomposites. Some insight into conduction mechanisms

    Science.gov (United States)

    Barroso-Bogeat, Adrián; Alexandre-Franco, María; Fernández-González, Carmen; Sánchez-González, José; Gómez-Serrano, Vicente

    2015-12-01

    From a commercial activated carbon (AC) and six metal oxide (Al2O3, Fe2O3, SnO2, TiO2, WO3 and ZnO) precursors, two series of AC-metal oxide nanocomposites are prepared by wet impregnation, oven-drying at 120 °C, and subsequent heat treatment at 200 or 850 °C in inert atmosphere. The temperature-dependent dc electrical conductivity of AC and the as-prepared nanocomposites is measured from room temperature up to ca. 200 °C in air atmosphere by the four-probe method. The decrease in conductivity for the hybrid materials as compared to AC is the result of a complex interplay between several factors, including not only the intrinsic conductivity, crystallite size, content and chemical nature of the supported nanoparticles, which ultimately depend on the precursor and heat treatment temperature, but also the adsorption of oxygen and water from the surrounding atmosphere. The conductivity data are discussed in terms of a thermally activated process. In this regard, both AC and the prepared nanocomposites behave as semiconductors, and the temperature-dependent conductivity data have been interpreted on the basis of the classical model proposed by Mott and Davis. Because of its high content of heteroatoms, AC may be considered as a heavily doped semiconductor, so that conduction of thermally excited carriers via acceptor or donor levels is expected to be the dominant mechanism. The activation energies for the hybrid materials suggest that the supported metal oxide nanoparticles strongly modify the electronic band structure of AC by introducing new trap levels in different positions along its band gap. Furthermore, the thermally activated conduction process satisfies the Meyer-Neldel rule, which is likely connected with the shift of the Fermi level due to the introduction of the different metal oxide nanoparticles in the AC matrix.

  14. Facile general route toward tunable Magnéli nanostructures and their use as thermoelectric metal oxide/carbon nanocomposites.

    Science.gov (United States)

    Portehault, David; Maneeratana, Vasana; Candolfi, Christophe; Oeschler, Niels; Veremchuk, Igor; Grin, Yuri; Sanchez, Clément; Antonietti, Markus

    2011-11-22

    Engineering nanoscale interfaces is a requisite for harnessing electrical and thermal transports within nanostructured materials, especially those destined for thermoelectric applications requiring an unusual combination of low thermal conductivity and electrical resistivity. Nanocomposites open up possibilities in this area, but are still bound to a very narrow range of materials. Here, we report a new approach combining the sol-gel process toward hybrid materials with spark plasma sintering (SPS) to yield functional nanocomposites based on substoichiometric titanium oxides Ti(n)O(2n-1), so-called Magnéli phases. The potential of this new approach is demonstrated by three results. First, multiple Ti(n)O(2n-1) compounds (n = 3, 4, 5, 6, 8) are obtained for the first time as sole nano-Magnéli crystalline phases with controlled specific surface areas from 55 to 300 m(2)·g(-1), classified as potential thermoelectric n-type metal oxides and paving the way toward advanced systems for energy-harvesting devices and optoelectronics. Second, this work combines the use of sol-gel and SPS processes to yield percolated nanocomposites based on metal oxide nanoparticles embedded in a carbon matrix with low electrical resistivity (2 × 10(-4) Ω·m for a Ti(4)O(7) compound) and reduced thermal conductivity (1 W·m(-1)·K(-1)) with respect to bulk phases. Finally, the discovered materials are reliable with thermoelectric figures of merit (ZT = 0.08) relatively high for n-type Ti-O-based systems and metal oxides. Thereby this study represents a proof of concept for the development of promising, cheaper, and more efficient thermoelectric conversion devices.

  15. Preparation of uniform nanoparticles of ultra-high purity metal oxides, mixed metal oxides, metals, and metal alloys

    Science.gov (United States)

    Woodfield, Brian F.; Liu, Shengfeng; Boerio-Goates, Juliana; Liu, Qingyuan; Smith, Stacey Janel

    2012-07-03

    In preferred embodiments, metal nanoparticles, mixed-metal (alloy) nanoparticles, metal oxide nanoparticles and mixed-metal oxide nanoparticles are provided. According to embodiments, the nanoparticles may possess narrow size distributions and high purities. In certain preferred embodiments, methods of preparing metal nanoparticles, mixed-metal nanoparticles, metal oxide nanoparticles and mixed-metal nanoparticles are provided. These methods may provide tight control of particle size, size distribution, and oxidation state. Other preferred embodiments relate to a precursor material that may be used to form nanoparticles. In addition, products prepared from such nanoparticles are disclosed.

  16. Microwave assisted facile synthesis of reduced graphene oxide-silver (RGO-Ag) nanocomposite and their application as active SERS substrate

    Energy Technology Data Exchange (ETDEWEB)

    Wadhwa, Heena, E-mail: heenawadhwa1988@gmail.com; Kumar, Devender, E-mail: devkumsaroha@kuk.ac.in; Mahendia, Suman, E-mail: mahendia@gmail.com; Kumar, Shyam, E-mail: profshyam@gmail.com

    2017-06-15

    The present paper represents the facile and rapid synthesis of reduced graphene oxide-silver (RGO-Ag) nanocomposite with the help of microwave irradiation. The graphene oxide (GO) solution has been prepared in bulk using Hummer's method followed by microwave assisted in-situ reduction of GO and silver nitrate (AgNO{sub 3}) by hydrazine hydrate in a short spam of 5 min. The prepared nanocomposite has been characterized using Transmission Electron Microscopy (TEM), X-Ray Diffraction (XRD) Scanning Electron Microscopy (SEM) and UV–Visible spectroscopy. TEM analysis shows that Ag nanoparticles with average size 32 nm are uniformly entangled with in RGO layers. The UV–Visible absorption spectrum of nanocomposite depicts the reduction of GO to RGO along with the formation of Ag nanoparticles with the presence of characteristic surface Plasmon resonance (SPR) peak of Ag nanoparticles at 422 nm. The performance of prepared nanocomposite has been tested as the active Surface Enhanced Raman Scattering (SERS) substrate for Rhodamine 6G with detection limit 0.1 μM. - Highlights: • The RGO and RGO-Ag nanocomposite were synthesized with microwave irradiation. • Ag nanoparticles of average size 32 nm are uniformly entangled within RGO layers. • RGO itself is a florescence quencher with SERS detection limit 1 μM for R6G. • RGO-Ag nanocomposite show good SERS activity for R6G with detection limit 0.1 μM.

  17. Synthesis of iron(II,III) oxide/zinc oxide/copper(II) oxide (Fe3O4/ZnO/CuO) nanocomposites and their photosonocatalytic property for organic dye removal.

    Science.gov (United States)

    Taufik, Ardiansyah; Saleh, Rosari

    2017-04-01

    A facile sol-gel method was adopted to synthesize iron(II,III) oxide/zinc oxide/copper(II) oxide (Fe3O4/ZnO/CuO) nanocomposites with various CuO loadings at a low temperature. The prepared nanocomposites were characterized by X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, UV-Vis spectroscopy, vibrating sample magnetometry, and Brunauer-Emmett-Teller (BET) surface area analyses. The photosonocatalytic properties of the nanocomposites were tested by methylene blue removal in aqueous solutions under the combination of UV or visible light and ultrasound. The catalyst with the lowest CuO loading exhibited the highest photosonocatalytic performance under UV light, while the fastest degradation under visible light was achieved at the highest CuO loading. Overall, the photosonocatalytic process with light and ultrasound irradiation led to more complete degradation compared to using light alone. According to the experiments performed with radical scavengers, the holes and OH radicals are the dominant oxidative species. The nanocomposites can be easily separated from the treated solution using an external magnetic field, and the samples remain very stable after 4 cycles. These results indicate that these materials have great potential for treating organic pollutants in wastewaters.

  18. Scanning and transmission electron microscopy investigation of multiwall carbon nanotube/nickel oxide nanocomposite thin films

    CSIR Research Space (South Africa)

    Roro, Kittessa T

    2011-12-01

    Full Text Available Owing to their unique electronic and optical properties, nanocomposite thin films are widely used for converting solar radiation therapy into other conventional energy forms, such as heat and electricity. Carbon nanotube-based composites which can...

  19. Influence of expanded graphite (EG and graphene oxide (GO on physical properties of PET based nanocomposites

    Directory of Open Access Journals (Sweden)

    Paszkiewicz Sandra

    2014-12-01

    Full Text Available This work is the continuation and refinement of already published communications based on PET/EG nanocomposites prepared by in situ polymerization1, 2. In this study, nanocomposites based on poly(ethylene terephthalate with expanded graphite were compared to those with functionalized graphite sheets (GO. The results suggest that the degree of dispersion of nanoparticles in the PET matrix has important effect on the structure and physical properties of the nanocomposites. The existence of graphene sheets nanoparticles enhances the crystallization rate of PET. It has been confirmed that in situ polymerization is the effective method for preparation nanocomposites which can avoid the agglomeration of nanoparticles in polymer matrices and improve the interfacial interaction between nanofiller and polymer matrix. The obtained results have shown also that due to the presence of functional groups on GO surface the interactions with PET matrix can be stronger than in the case of exfoliated graphene (EG and matrix.

  20. Nickel oxide/carbon nanotube/polyaniline nanocomposite as bifunctional anode catalyst for high-performance Shewanella-based dual-chamber microbial fuel cell.

    Science.gov (United States)

    Nourbakhsh, Fatemeh; Mohsennia, Mohsen; Pazouki, Mohammad

    2017-08-01

    A novel nickel oxide/carbon nanotube/polyaniline (NCP) nanocomposite has been prepared and used to modify the electrocatalytic properties of carbon cloth anode in fabricating dual-chamber MFC. The prepared nanocomposite was characterized by scanning electron microscopy, X-ray diffraction, and fourier transform infrared spectroscopy. The carbon cloth coated with the NCP nanocomposite showed the enhanced electrochemical performance as compared to bare carbon cloth anode. The electrochemical properties of the fabricated MFC with the modified anode have been investigated by linear sweep voltammetry and electrochemical impedance spectroscopy. The maximum power density of the MFC using the novel NCP nanocomposite-carbon cloth anode increased by 61.88% compared to that of the bare carbon cloth anode. In comparison to the bare carbon cloth anode, the new composite anode showed 26.8% enhancement of current density output which it can be due to the enhancement of the charge transfer capability.

  1. Ultrasonic-assisted synthesis of Pd-Pt/carbon nanotubes nanocomposites for enhanced electro-oxidation of ethanol and methanol in alkaline medium.

    Science.gov (United States)

    Yang, Guohai; Zhou, Yazhou; Pan, Horng-Bin; Zhu, Chengzhou; Fu, Shaofang; Wai, Chien M; Du, Dan; Zhu, Jun-Jie; Lin, Yuehe

    2016-01-01

    Herein, a facile ultrasonic-assisted strategy was proposed to fabricate the Pd-Pt alloy/multi-walled carbon nanotubes (Pd-Pt/CNTs) nanocomposites. A good number of Pd-Pt alloy nanoparticles with an average of 3.4 ± 0.5 nm were supported on sidewalls of CNTs with uniform distribution. The composition of the Pd-Pt/CNTs nanocomposites could also be easily controlled, which provided a possible approach for the preparation of other architectures with anticipated properties. The Pd-Pt/CNTs nanocomposites were extensively studied by electron microscopy, induced coupled plasma atomic emission spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy, and applied for the ethanol and methanol electro-oxidation reaction in alkaline medium. The electrochemical results indicated that the nanocomposites had better electrocatalytic activities and stabilities, showing promising applications for fuel cells. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. Microwave-assisted synthesis of Mn{sub 3}O{sub 4} nanoparticles@reduced graphene oxide nanocomposites for high performance supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    She, Xiao; Zhang, Xinmin; Liu, Jingya [School of Materials Science and Engineering, Wuhan Institute of Technology, Wuhan 430073 (China); Li, Liang, E-mail: msell08@163.com [School of Materials Science and Engineering, Wuhan Institute of Technology, Wuhan 430073 (China); Yu, Xianghua; Huang, Zhiliang [School of Materials Science and Engineering, Wuhan Institute of Technology, Wuhan 430073 (China); Shang, Songmin, E-mail: shang.songmin@polyu.edu.hk [Institute of Textiles and Clothing, The Hong Kong Polytechnic University, Hong Kong (China)

    2015-10-15

    Highlights: • Mn{sub 3}O{sub 4}@rGO nanocomposites were prepared by one-step microwave-assisted method. • The growth of Mn{sub 3}O{sub 4} and the reduction of graphene oxide occurred simultaneously. • Specific capacitance of the nanocomposite is higher than those of rGO and Mn{sub 3}O{sub 4}. • The nanocomposites have good rate capability and cycling stability. - ABSTRACT: One-step microwave-assisted synthetic route for the fabrication of Mn{sub 3}O{sub 4} nanoparticles@reduced graphene oxide (Mn{sub 3}O{sub 4}@rGO) nanocomposites has been demonstrated. The morphological structures of the nanocomposites are characterized by Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, X-ray diffraction (XRD), thermogravimetric analyses (TGA), and scanning electron microscopy (SEM), respectively. All of the results indicate that the microwave-assisted synthesis results in the growth of Mn{sub 3}O{sub 4} and the reduction of graphene oxide simultaneously in ethylene glycol-water system. The specific capacitance of the as-prepared Mn{sub 3}O{sub 4}@rGO nanocomposite is higher than those of rGO and pure Mn{sub 3}O{sub 4}, which indicates the synergetic interaction between rGO and Mn{sub 3}O{sub 4}. The nanocomposites also have good rate capability and cycling stability in electrochemical experiments. This facile technique may be extended to the large scale and cost effective production of other composites based on graphene and metal oxide for many applications.

  3. Effects of reducibility of graphene oxide nanosheets on preparation of AgNPs/GO nanocomposites and their electrocatalytic performance

    Energy Technology Data Exchange (ETDEWEB)

    Dou, Yanpeng; Peng, Junjun, E-mail: john-peng@whu.edu.cn; Li, Wei; Li, Ming; Liu, Huihong; Zhang, Hanmin [Wuhan Textile University, College of Chemistry and Chemical Engineering (China)

    2015-12-15

    Silver nanoparticles/graphene oxide (AgNPs/GO) nanocomposites were prepared in a solution of AgNO{sub 3} and GO. The GO serves not only as a reductant but also as a substrate to support the as-reduced silver nanoparticles. The reducibility of GO was investigated by analyzing the influence factors such as pH, duration, the reaction temperature, and the weight ratio of AgNO{sub 3} and GO in the AgNP/GO nanocomposite mixture, which were evaluated by the UV–vis absorption spectroscopy. The results demonstrated that Ag nanoparticles with an average diameter of 5–10 nm were uniformly dispersed on the surface of GO nanosheets under the optimum synthesis conditions of pH between 8 and 11, weight ratio of AgNO{sub 3} and GO between 55 % and 60 %, and at 80 °C for 6 h. Moreover, the obtained AgNPs/GO nanocomposites exhibit good electrocatalytic activity for the reduction of p-nitrophenol to 4-(hydroxyamino) phenol.

  4. Device level optimization of poly(vinylidene fluoride-trifluoroethylene)–zinc oxide polymer nanocomposite thin films for ferroelectric applications

    Energy Technology Data Exchange (ETDEWEB)

    C K, Subash, E-mail: cksubash08@gmail.com; Valiyaneerilakkal, Uvais; Varghese, Soney [Nanomaterials and Device Research Laboratory, School of Nano Science and Technology, National Institute of Technology Calicut, Calicut, Kerala 673601 (India); Singh, Kulwant [Nanomaterials and Device Research Laboratory, School of Nano Science and Technology, National Institute of Technology Calicut, Calicut, Kerala 673601 (India); Department of ECE, B.K. Birla Institute of Engineering and Technology, Pilani, Rajasthan 333031 (India)

    2015-11-28

    Polymer nanocomposite was prepared using poly(vinylidene fluoride-trifluoroethylene) and zinc oxide (ZnO) nanopowder, which are ferroelectric in nature. Nanocomposite was prepared in various concentrations(0.2, 0.4, 0.8, and 1 wt. %) using probe ultra-sonication, followed by spin coating and annealing at 120 °C for 2 h to improve the formation of β-phase. Metal-ferroelectric-metal capacitor was fabricated using this optimized thin film as a ferroelectric layer. Device level optimization was carried out by polarization-electric field (P-E) hysteresis studies of this film, which shows polarization enhancement of composite. Various characterization techniques like atomic force microscopy, Fourier transform infra-red spectroscopy (FT-IR), Differential scanning calorimetry, and X-ray diffraction were used to study the β-phase formation of nancomposite. The capacitance–voltage (C-V) and current-voltage (I-V) characteristics were studied through varying frequency and temperature. C-V measurements show an increase of 79% in the capacitance of polymer nanocomposite, which can be used for the fabrication of ferroelectric devices.

  5. Zeolitic Imidazolate Framework/Graphene Oxide Hybrid Nanosheets Functionalized Thin Film Nanocomposite Membrane for Enhanced Antimicrobial Performance.

    Science.gov (United States)

    Wang, Jing; Wang, Yuanming; Zhang, Yatao; Uliana, Adam; Zhu, Junyong; Liu, Jindun; Van der Bruggen, Bart

    2016-09-28

    Inspired by the rational design concept, a novel antimicrobial agent zeolitic imidazolate framework-8 (ZIF-8)/graphene oxide (GO) was synthesized and utilized as a novel and efficient bactericidal agent to fabricate antimicrobial thin film nanocomposite (TFN) membranes via interfacial polymerization. The resultant hybrid nanosheets not only integrates the merits of both ZIF-8 and GO but also yields a uniform dispersion of ZIF-8 onto GO nanosheets simultaneously, thus effectively eliminating the agglomeration of ZIF-8 in the active layer of membranes. A ZIF-8/GO thin film nanocomposite (TFN-ZG) membrane with typical water permeability (40.63 L m(-2) h(-1) MPa(-1)) allows for efficient bivalent salt removal (rejections of Na2SO4 and MgSO4 were 100% and 77%, respectively). Furthermore, the synthesized ZIF-8/GO nanocomposites were verified to have an optimal antimicrobial activity (MIC,128 μg/mL) in comparison with ZIF-8 and GO separately, which sufficiently endowed the TFN-ZG membrane with excellent antimicrobial activity (84.3% for TFN-ZG3). Besides, the antimicrobial mechanisms of ZIF-8/GO hybrid nanosheets and TFN-ZG membranes were proposed. ZIF-8/GO functionalized membrane with high antimicrobial activity and salt retention denoted its great potential in water desalination, and we suggest that ZIF-8 based crystal may offer a new pathway for the synthesis of a multifunctional bactericide.

  6. Structure and Catalytic Behavior of CuO-ZrO-CeO2 Mixed Oxides

    Institute of Scientific and Technical Information of China (English)

    王恩过; 陈诵英

    2002-01-01

    The effect of doping CuO on the structure and properties of zirconia-ceria mixed oxide was studied. The results show that addition of CuO decreases the reduction temperature of ceria, and stabilizes the cubic structure of mixed oxides, and enhances catalytic activity of CuO-ZrO-CeO2 mixed oxides for CO oxidation. Increasing ceria content in the mixed oxides can enhance the catalytic activity, but some impurities such as sulfate make catalytic activity falling. There is little effect of calcination temperature on catalytic activities, implying that these catalysts are effective with good thermal stability.

  7. In vitro and in vivo evaluation of a new nanocomposite, containing high density polyethylene, tricalcium phosphate, hydroxyapatite, and magnesium oxide nanoparticles.

    Science.gov (United States)

    Pourdanesh, Fereydoun; Jebali, Ali; Hekmatimoghaddam, Seyedhossein; Allaveisie, Azra

    2014-07-01

    In this study, a new nanocomposite, which contained high density polyethylene (HDPE), tricalcium phosphate (Ca3(PO4)2) nanoparticles (TCP NPs), hydroxyapatite nanoparticles (HA NPs), and magnesium oxide nanoparticles (MgO NPs) was prepared. As in vitro experiment, human osteoblasts (HOB) cells were exposed to pristine HDPE and its nanocomposite for a period of 1, 4, and 7 days at 37 °C, and then different assays were carried out, including osteoblast cell proliferation, Trypan blue staining, cell viability, alkaline phosphatase (ALP), and cell adhesion. Antibacterial property of pristine HDPE and its nanocomposite was evaluated, and also their mechanical properties were measured after 2 and 4 months. As in vivo experiment, pristine HDPE and its nanocomposite were separately implanted on calvarium bone of rabbits, and tissue inflammation and osteogenesis were investigated after 2, 4, and 6 months. In case of HOB cells treated with HDPE or nanocomposite, as incubation time was increased, cell proliferation, live/dead ratio, and cell viability were decreased. But, the ALP activity and cell adhesion of HOB cells which treated with nanocomposite were raised after increase of incubation time. This study demonstrated that although the mechanical properties of nanocomposite were similar to HDPE sheet, but their antibacterial property was not similar. The in vivo experiment showed that both pristine HDPE and its nanocomposite had same inflammation responses. Interestingly, osteogenesis was observed after 2 months at bone/nanocomposite interface, and was highly increased after 4 and 6 months. It must be noted that such pattern was not seen at bone/HDPE interface.

  8. Comparison study on photocatalytic oxidation of pharmaceuticals by TiO2-Fe and TiO2-reduced graphene oxide nanocomposites immobilized on optical fibers.

    Science.gov (United States)

    Lin, Lu; Wang, Huiyao; Jiang, Wenbin; Mkaouar, Ahmed Radhi; Xu, Pei

    2017-03-08

    Incorporating reduced graphene oxide (rGO) or Fe(3+) ions in TiO2 photocatalyst could enhance photocatalytic degradation of organic contaminants in aqueous solutions. This study characterized the photocatalytic activities of TiO2-Fe and TiO2-rGO nanocomposites immobilized on optical fibers synthesized by polymer assisted hydrothermal deposition method. The photocatalysts presented a mixture phase of anatase and rutile in the TiO2-rGO and TiO2-Fe nanocomposites. Doping Fe into TiO2 particles (2.40eV) could reduce more band gap energy than incorporating rGO (2.85eV), thereby enhancing utilization efficiency of visible light. Incorporating Fe and rGO in TiO2 decreased significantly the intensity of TiO2 photoluminescence signals and enhanced the separation rate of photo-induced charge carriers. Photocatalytic performance of the synthesized nanocomposites was measured by the degradation of three pharmaceuticals under UV and visible light irradiation, including carbamazepine, ibuprofen, and sulfamethoxazole. TiO2-rGO exhibited higher photocatalytic activity for the degradation of pharmaceuticals under UV irradiation, while TiO2-Fe demonstrated more suitable for visible light oxidation. The results suggested that the enhanced photocatalytic performance of TiO2-rGO could be attributed to reduced recombination rate of photoexcited electrons-hole pairs, but for TiO2-Fe nanocomposite, narrower band gap would contribute to increased photocatalytic activity.

  9. Novel ZnO:Ag nanocomposites induce significant oxidative stress in human fibroblast malignant melanoma (Ht144 cells

    Directory of Open Access Journals (Sweden)

    Syeda Arooj

    2015-02-01

    Full Text Available The use of photoactive nanoparticles (NPs such as zinc oxide (ZnO and its nanocomposites has become a promising anticancer strategy. However, ZnO has a low photocatalytic decomposition rate and the incorporation of metal ions such as silver (Ag improves their activity. Here different formulations of ZnO:Ag (1, 3, 5, 10, 20 and 30% Ag were synthesized by a simple co-precipitation method and characterized by powder X-ray diffraction, scanning electron microscopy, Rutherford back scattering and diffuse reflectance spectroscopy for their structure, morphology, composition and optical band gap. The NPs were investigated with regard to their different photocatalytic cytotoxic effects in human malignant melanoma (HT144 and normal (HCEC cells. The ZnO:Ag nanocomposites killed cancer cells more efficiently than normal cells under daylight exposure. Nanocomposites having higher Ag content (10, 20 and 30% were more toxic compared to low Ag content (1, 3 and 5%. For HT144, under daylight exposure, the IC50 values were ZnO:Ag (10%: 23.37 μg/mL, ZnO:Ag (20%: 19.95 μg/mL, and ZnO:Ag (30%: 15.78 μg/mL. ZnO:Ag (30% was toxic to HT144 (IC50: 23.34 μg/mL in dark as well. The three nanocomposites were further analyzed with regard to their ability to generate reactive oxygen species (ROS and induce lipid peroxidation. The particles led to an increase in levels of ROS at cytotoxic concentrations, but only HT144 showed strongly induced MDA level. Finally, NPs were investigated for the ROS species they generated in vitro. A highly significant increase of 1O2 in the samples exposed to daylight was observed. Hydroxyl radical species, HO•, were also generated to a lesser extent. Thus, the incorporation of Ag into ZnO NPs significantly improves their photo-oxidation capabilities. ZnO:Ag nanocomposites could provide a new therapeutic option to selectively target cancer cells.

  10. Mass transport in mixed conducting perovskite related oxides

    CERN Document Server

    Shaw, C K M

    2001-01-01

    mechanical and chemical stability of LSCN under practical operating temperatures have been measured and related to long term stability in typical SOFC assemblies. The phase stability and the effect of preparation conditions under different atmospheres on La sub 2 Ni sub 1 sub - sub x Co sub x O sub 4 sub + subdelta compounds were examined using high temperature X-ray diffraction. Fast oxygen uptake at low temperatures was observed in these studies indicating rapid oxygen diffusion, which was confirmed by isotope exchange investigations. The oxygen diffusion and surface exchange data obtained from IEDP-SIMS measurements of La sub 2 Ni sub 0 sub . sub 8 Co sub 0 sub . sub 2 O sub 4 sub + subdelta have enabled suppositions to be made regarding the reduction process and aided further interpretation of the defect model for these oxides. Mixed ionic electronic conducting oxides of the perovskite structure have attracted great interest in the field of solid oxide electrochemical devices. Their ability to allow poten...

  11. Electrochromic and electrochemical capacitive properties of tungsten oxide and its polyaniline nanocomposite films obtained by chemical bath deposition method

    CSIR Research Space (South Africa)

    Nwanya, AC

    2014-05-01

    Full Text Available Kenneth I. Ozoemena Fabian I. EzemaISE student member.ISE member. PII: S0013...-mail address: fiezema@yahoo.com 1 ISE student member 2 ISE member Page 2 of 31 Ac ce pte d M an us cri pt 2 Polyanine and its nanocomposite WO3/PANI films were deposited on Fluorine doped tin oxide (FTO) glass slides by simple Chemical Bath Deposition Method...

  12. Laser synthesis of a copper-single-walled carbon nanotube nanocomposite via molecular-level mixing and non-equilibrium solidification

    Science.gov (United States)

    Tu, Jay F.; Rajule, Nilesh; Molian, Pal; Liu, Yi

    2016-12-01

    A copper-single-walled carbon nanotube (Cu-SWCNT) metal nanocomposite could be an ideal material if it can substantially improve the strength of copper while preserving the metal’s excellent thermal and electrical properties. However, synthesis of such a nanocomposite is highly challenging, because copper and SWCNTs do not form intermetallic compounds and are insoluble; as a result, there are serious issues regarding wettability and fine dispersion of SWCNTs within the copper matrix. In this paper we present a novel wet process, called the laser surface implantation process (LSI), to synthesize Cu-SWCNT nanocomposites by mixing SWCNTs into molten copper. The LSI process includes drilling several microholes on a copper substrate, filling the microholes with SWCNTs suspended in solution, and melting the copper substrate to create a micro-well of molten copper. The molten copper advances radially outward to engulf the microholes with pre-deposited SWCNTs to form the Cu-SWCNT implant upon solidification. Rapid and non-equilibrium solidification is achieved due to copper’s excellent heat conductivity, so that SWCNTs are locked in position within the copper matrix without agglomerating into large clusters. This wet process is very different from the typical dry processes used in powder metallurgy. Very high hardness improvement, up to 527% over pure copper, was achieved, confirmed by micro-indentation tests, with only a 0.23% SWCNT volume fraction. The nanostructure of the nanocomposite was characterized by TEM imaging, energy-dispersive x-ray spectroscopy mapping and spectroscopy measurements. The SWCNTs were found to be finely dispersed within the copper matrix with cluster sizes in the range of nanometers, achieving the goal of molecular-level mixing.

  13. High-Performance All-Solid-State Lithium-Sulfur Battery Enabled by a Mixed-Conductive Li2S Nanocomposite.

    Science.gov (United States)

    Han, Fudong; Yue, Jie; Fan, Xiulin; Gao, Tao; Luo, Chao; Ma, Zhaohui; Suo, Liumin; Wang, Chunsheng

    2016-07-13

    All-solid-state lithium-sulfur batteries (ASSLSBs) using highly conductive sulfide-based solid electrolytes suffer from low sulfur utilization, poor cycle life, and low rate performance due to the huge volume change of the electrode and the poor electronic and ionic conductivities of S and Li2S. The most promising approach to mitigate these challenges lies in the fabrication of a sulfur nanocomposite electrode consisting of a homogeneous distribution of nanosized active material, solid electrolyte, and carbon. Here, we reported a novel bottom-up method to synthesize such a nanocomposite by dissolving Li2S as the active material, polyvinylpyrrolidone (PVP) as the carbon precursor, and Li6PS5Cl as the solid electrolyte in ethanol, followed by a coprecipitation and high-temperature carbonization process. Li2S active material and Li6PS5Cl solid electrolyte with a particle size of ∼4 nm were uniformly confined in a nanoscale carbon matrix. The homogeneous nanocomposite electrode consisting of different nanoparticles with distinct properties of lithium storage capability, mechanical reinforcement, and ionic and electronic conductivities enabled a mechanical robust and mixed conductive (ionic and electronic conductive) sulfur electrode for ASSLSB. A large reversible capacity of 830 mAh/g (71% utilization of Li2S) at 50 mA/g for 60 cycles with a high rate performance was achieved at room temperature even at a high loading of Li2S (∼3.6 mg/cm(2)). This work provides a new strategy to design a mechanically robust, mixed conductive nanocomposite electrode for high-performance all-solid-state lithium sulfur batteries.

  14. Oxidation control of fluxes for mixed-valent inorganic oxide materials synthesis

    Science.gov (United States)

    Schrier, Marc David

    This dissertation is concerned with controlling the flux synthesis and ensuing physical properties of mixed-valence metal oxides. Molten alkali metal nitrates and hydroxides have been explored to determine and exploit their variable redox chemistries for the synthesis of mixed-valent oxide materials. Cationic and anionic additives have been utilized in these molten salts to control the relative concentrations of the redox-active species present to effectively tune and cap the electrochemical potential of the flux. Atoms like bismuth, copper, and manganese are capable of providing different numbers of electrons for bonding. With appropriate doping near the metal-insulator transition, many of these mixed-valent inorganic metal oxides exhibit extraordinary electronic and magnetic properties. Traditionally, these materials have been prepared by classical high temperature solid state routes where microscopic homogeneity is hard to attain. In these routes, the starting composition dictates the doping level, and in turn, the formal oxidation state achieved. Molten flux syntheses developed in this work have provided the potential for preparing single-phase, homogeneous, and crystalline materials. The redox-active fluxes provide a medium for enhanced doping and mixed-valency control in which the electrochemical potential adjusts the formal oxidation state, and the doping takes place to maintain charge neutrality. The two superconductor systems investigated are: (1) the potassium-doped barium bismuth oxides, and (2) the alkali metal- and alkaline earth metal-doped lanthanum copper oxides. Controlled oxidative doping has been achieved in both systems by two different approaches. The superconducting properties of these materials have been assessed, and the materials have been characterized by powder X-ray diffraction and e-beam microprobe elemental analyses. In the course of these studies, several other materials have been identified. Analysis of these materials, and the

  15. Influence of the chemical treatment in sodium clay on barrier property of propylene nanocomposites obtained by melt mixing;Influencia do tratamento quimico em argila sodica na propriedade de barreira de nanocompositos de polipropileno obtidos por mistura no fundido

    Energy Technology Data Exchange (ETDEWEB)

    Araujo, Sabina B.N. de; Marques, Maria de Fatima V., E-mail: fmarques@ima.ufrj.b [Universidade Federal do Rio de Janeiro (IMA/UFRJ), RJ (Brazil). Inst. de Macromoleculas Profa. Eloisa Mano

    2009-07-01

    In this work, the influence of the chemical treatment in sodium clay on the barrier property of polypropylene nanocomposites was evaluated. Nanocomposites of PP/clay were obtained by melting intercalation using two different chemically treated clays and the original one was mixed to PP for comparison. The change in the clay structure caused by the chemical treatment was evaluated by X-ray diffractometry. The influence of this modification on the barrier property of the obtained PP nanocomposites was evaluated by analysis of oxygen permeability. (author)

  16. Perovskite-type Mixed Oxides Catalyst for Complete Oxidation of Acetone

    Institute of Scientific and Technical Information of China (English)

    DUAN; ZhiYing

    2001-01-01

    The catalytic oxidation of VOCs (volatile organic compounds) is an attractive subject in the field of environmental protection now. Furthermore, most countries have made out regulations m controlling the maximum content of VOCs in some places. Presently, the leading way of domestic and foreign means to eliminate VOCs is to completely oxidize VOCs into carbon dioxide and water in presence of noble metal catalyst. But noble metal is expensive for lack of resource[2]. So it is insistent to research a low-cost catalyst for removal of VOCs. In this work, we have used some base metals (such as La, Sr, Ce, Ni, Cu) to synthesize mixed oxides catalyst supported on γ-A12O3. We have investigated the catalytic properties in the complete oxidation of acetone over the catalyst prepared and achieved an exciting result.……

  17. Perovskite-type Mixed Oxides Catalyst for Complete Oxidation of Acetone

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@ The catalytic oxidation of VOCs (volatile organic compounds) is an attractive subject in the field of environmental protection now. Furthermore, most countries have made out regulations m controlling the maximum content of VOCs in some places. Presently, the leading way of domestic and foreign means to eliminate VOCs is to completely oxidize VOCs into carbon dioxide and water in presence of noble metal catalyst. But noble metal is expensive for lack of resource[2]. So it is insistent to research a low-cost catalyst for removal of VOCs. In this work, we have used some base metals (such as La, Sr, Ce, Ni, Cu) to synthesize mixed oxides catalyst supported on γ-A12O3. We have investigated the catalytic properties in the complete oxidation of acetone over the catalyst prepared and achieved an exciting result.

  18. Properties of mixed molybdenum oxide iridium oxide thin films synthesized by spray pyrolysis

    Science.gov (United States)

    Patil, P. S.; Kawar, R. K.; Sadale, S. B.; Inamdar, A. I.; Deshmukh, H. P.

    2006-09-01

    Molybdenum-doped iridium oxide thin films have been deposited onto corning glass- and fluorine-doped tin oxide coated corning glass substrates at 350 °C by using a pneumatic spray pyrolysis technique. An aqueous solution of 0.01 M ammonium molybdate was mixed with 0.01 M iridium trichloride solution in different volume proportions and the resultant solution was used as a precursor solution for spraying. The as-deposited samples were annealed at 600 °C in air medium for 1 h. The structural, electrical and optical properties of as-deposited and annealed Mo-doped iridium oxide were studied and values of room temperature electrical resistivity, and thermoelectric power were estimated. The as-deposited samples with 2% Mo doping exhibit more pronounced electrochromism than other samples, including pristine Ir oxide.

  19. Platinum-Niobium(V Oxide/Carbon Nanocomposites Prepared By Microwave Synthesis For Ethanol Oxidation

    Directory of Open Access Journals (Sweden)

    Virginija KEPENIENĖ

    2016-05-01

    Full Text Available In the present work, Pt nanoparticles were deposited by means of microwave synthesis on the primary carbon supported Nb2O5 composite which was prepared in two different ways: (A by dispersion of Nb2O5 and carbon with the mass ratio equal to 1:1 in a 2-propanol solution by ultrasonication for 30 min. with further desiccation of the mixture and (B by heating the Nb2O5/C composite obtained according to the procedure (A at 500 °C for 2 h. The transmission electron microscopy was used to determine the shape and the size of catalyst particles. X-ray diffraction and inductively coupled plasma optical emission spectroscopy were employed to characterize the structure and composition of the synthesized catalysts. The electrocatalytic activity of the synthesized catalysts towards the oxidation of ethanol in an alkaline medium was investigated by means of cyclic voltammetry.DOI: http://dx.doi.org/10.5755/j01.ms.22.2.8609

  20. Investigation of space charge distribution of low-density polyethylene/GO-GNF (graphene oxide from graphite nanofiber) nanocomposite for HVDC application.

    Science.gov (United States)

    Kim, Yoon Jin; Ha, Son-Tung; Lee, Gun Joo; Nam, Jin Ho; Ryu, Ik Hyun; Nam, Su Hyun; Park, Cheol Min; In, Insik; Kim, Jiwan; Han, Chul Jong

    2013-05-01

    This paper reported a research on space charge distribution in low-density polyethylene (LDPE) nanocomposites with different types of graphene and graphene oxide (GO) at low filler content (0.05 wt%) under high DC electric field. Effect of addition of graphene oxide or graphene, its dispersion in LDPE polymer matrix on the ability to suppress space charge generation will be investigated and compared with MgO/LDPE nanocomposite at the same filler concentration. At an applied electric field of 80 kV/mm, a positive packet-like charge was observed in both neat LDPE, MgO/LDPE, and graphene/LDPE nanocomposites, whereas only little homogenous space charge was observed in GO/LDPE nanocomposites, especially with GO synthesized from graphite nano fiber (GNF) which is only -100 nm in diameter. Our research also suggests that dispersion of graphene oxide particles on the polymer matrix plays a significant role to the performance of nanocomposites on suppressing packet-like space charge. From these results, it is expected that nano-sized GO synthesized from GNF can be a promising filler material to LDPE composite for HVDC applications.

  1. Characterization of manganese-gallium mixed oxide powders

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez Escribano, V.; Fernandez Lopez, E.; Sanchez Huidobro, P. [Universidad de Salamanca, Dept. de Quimica Inorganica (Spain); Panizza, M.; Resini, C.; Busca, G. [UNiversita di Genova, Dipt. di Ingegneria Chimica e di Processo, Genova (Italy); Resini, C. [Istituto Nazionale di Fisica della Materia, INFM (Spain); Gallardo- Amores, J.M. [Universidad Complutense, Dept. de Quimica Inorganica, Lab. Complutense de Altas Presiones, Madrid (Spain)

    2003-12-01

    Mn-Ga mixed oxides have been prepared by coprecipitation of the corresponding oxo-hydroxides as powders and have been characterized in relation to their structural and optical properties. The materials have been characterized by XRD, TG-DTA, skeletal IR and UV-visible-NIR spectroscopies. Large solubility of Mn in the diaspore type {alpha}-GaOOH oxo-hydroxide has been found. The spinel related structures of hausmannite Mn{sub 3}O{sub 4} and of {beta}-gallia present large reciprocal solubilities at least in a metastable form. At high temperature also bixbyite-type {alpha}-Mn{sub O3} solid solutions containing up to 20% at. Ga have been observed. (authors)

  2. Formation of stable nanocomposite clays from small peptides reacted with montmorillonite and illite-smectite mixed layer clays

    Science.gov (United States)

    Block, K. A.; Katz, A.; LeBlanc, J.; Peña, S.; Gottlieb, P.

    2015-12-01

    Understanding how organic compounds interact with clay minerals and which functional groups result in the strongest bonds is pivotal to achieving a better understanding of how mineral composition affects the residence time of carbon and nitrogen in soils. In this work, we describe how small peptides derived from tryptone casein digest are dissolved and suspended with clay minerals to examine the nature of OM adsorption to mineral surfaces and the resulting effect on clay mineral structure. XRD analyses indicate that peptides intercalation results in expansion of the d001 spacing of montmorillonite (Mt) and the smectite component of a 70-30 illite-smectite mixed layer clay (I-S) and poorer crystallinity overall as a result of exfoliation of tactoids. Peptide adsorption is concentration-dependent, however, surface adsorption appears to mediate interlayer adsorption in Mt reaching a maximum of 16% of the mass of the organoclay complex, indicating that at a critical concentration, peptide intercalation will supersede surface adsorption resulting in a more stable attachment. In I-S the degree of surface adsorption and intercalation is proportional to concentration, however, surface adsorption is not a priming mechanism for interlayer adsorption. Thermogravimetric analysis of the organoclay complexes determined by TGA coupled to GC-MS indicate that the most prominent product species measured was 1-(1-Trimethylsiloxyethenyl)-3-trimethylsiloxy-benzene, likely from tryptophan monomer decomposition. The compound was detected over a broad temperature range, greater than 300 oC, during pyrolysis and suggests a carbon-silicon covalent bond formed between the peptide and tetrahedral layers in the clay. An additional silicon-bearing VOC detected at lower pyrolysis temperature by GC was N,N-Diethyl-1-(trimethylsilyl)-9,10-didehydroergoline-8-carboxamide, likely derived from a lysine-bearing peptide derivative. We hypothesize that hydrophobic (non-ionic) peptides react with silanol

  3. Yttrium bismuth titanate pyrochlore mixed oxides for photocatalytic hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Merka, Oliver

    2012-10-18

    In this work, the sol-gel synthesis of new non-stoichiometric pyrochlore titanates and their application in photocatalytic hydrogen production is reported. Visible light response is achieved by introducing bismuth on the A site or by doping the B site by transition metal cations featuring partially filled d orbitals. This work clearly focusses on atomic scale structural changes induced by the systematical introduction of non-stoichiometry in pyrochlore mixed oxides and the resulting influence on the activity in photocatalytic hydrogen production. The materials were characterized in detail regarding their optical properties and their atomic structure. The pyrochlore structure tolerates tremendous stoichiometry variations. The non-stoichiometry in A{sub 2}O{sub 3} rich compositions is compensated by distortions in the cationic sub-lattice for the smaller Y{sup 3+} cation and by evolution of a secondary phase for the larger Bi{sup 3+} cation on the A site. For TiO{sub 2} rich compositions, the non-stoichiometry leads to a special vacancy formation in the A and optionally O' sites. It is shown that pyrochlore mixed oxides in the yttrium bismuth titanate system represent very active and promising materials for photocatalytic hydrogen production, if precisely and carefully tuned. Whereas Y{sub 2}Ti{sub 2}O{sub 7} yields stable hydrogen production rates over time, the bismuth richer compounds of YBiTi{sub 2}O{sub 7} and Bi{sub 2}Ti{sub 2}O{sub 7} are found to be not stable under irradiation. This drawback is overcome by applying a special co-catalyst system consisting of a precious metal core and a Cr{sub 2}O{sub 3} shell on the photocatalysts.

  4. Calculational Benchmark Problems for VVER-1000 Mixed Oxide Fuel Cycle

    Energy Technology Data Exchange (ETDEWEB)

    Emmett, M.B.

    2000-03-17

    Standard problems were created to test the ability of American and Russian computational methods and data regarding the analysis of the storage and handling of Russian pressurized water reactor (VVER) mixed oxide fuel. Criticality safety and radiation shielding problems were analyzed. Analysis of American and Russian multiplication factors for fresh fuel storage for low-enriched uranium (UOX), weapons- (MOX-W) and reactor-grade (MOX-R) MOX differ by less than 2% for all variations of water density. For shielding calculations for fresh fuel, the ORNL results for the neutron source differ from the Russian results by less than 1% for UOX and MOX-R and by approximately 3% for MOX-W. For shielding calculations for fresh fuel assemblies, neutron dose rates at the surface of the assemblies differ from the Russian results by 5% to 9%; the level of agreement for gamma dose varies depending on the type of fuel, with UOX differing by the largest amount. The use of different gamma group structures and instantaneous versus asymptotic decay assumptions also complicate the comparison. For the calculation of dose rates from spent fuel in a shipping cask, the neutron source for UOX after 3-year cooling is within 1% and for MOX-W within 5% of one of the Russian results while the MOX-R difference is the largest at over 10%. These studies are a portion of the documentation required by the Russian nuclear regulatory authority, GAN, in order to certify Russian programs and data as being acceptably accurate for the analysis of mixed oxide fuels.

  5. The Preparation, Characterization and Photocatalytic Activity of Mixed P25/CeO2 Nanocomposites

    Science.gov (United States)

    Liu, I.-Tsan; Hon, Min-Hsiung; Teoh, Lay Gaik

    2017-01-01

    This study uses the wet chemical method to synthesize P25 (TiO2)/CeO2 composites by mixing P25 and Ce(NO3)3·6H2O at different volumetric concentrations. X-ray diffraction, transmission electron microscopy and ultraviolet-visible diffuse reflectance spectroscopy are used to analyze the structure, morphology, optical properties and photocatalytic activity of the TiO2/CeO2 composites with different compositions. The pollutant, methylene blue solution, was used for analysis. The results show that the photocatalytic activity of the composite catalysts is greater than that of pure TiO2 or pure CeO2. The catalyst, TiO2 55%/CeO2 (v/v), exhibits the greatest level of photocatalytic activity.

  6. Preparation and characterization of polyaniline/indium(III) oxide (PANi/In2O3) nanocomposite thin film

    Science.gov (United States)

    Yan, Xiaolei; Xie, Guangzhong; Du, Xiaosong; Tai, Huiling; Jiang, Yadong

    2009-05-01

    In the last few decades, conductive polymers such as polyaniline, polypyrrole, and polythiophene have been widely investigated as effective sensitive materials for chemical gas sensors. Among them, polyaniline (PANI) is frequently used because of its ease and cheap of synthesis, environmental stability and intrinsic redox reaction. However, problems with these conductive polymers include their low processing ability, poor mechanical strength and chemical stability. There are tremendous approaches for the enhancement of mechanical strength and chemical stability of organic materials by combining organic materials with inorganic counterparts in nano-size to form composite materials..which would optimize the characteristics of gas sensors. In the paper, polyaniline/Indium(III) Oxide(PANi/In2O3) nanocomposite thin films was prepared on a quartz substrate by combination techniques of electrostatic self-assembly and in situ chemical oxidation polymerization at 10°C. Infrared spectrum analysis (IR) of the composite and scanning electron microscope(SEM) of nanocomposite thin films were performed. PANi/In2O3 nanocomposite thin film gas sensor was fabricated on AT-Cut quartz crystal microbalance(QCM) of Ag electrodes, and the sensitive properties of gas sensor to CH4 and CO are characterized and analyzed. The results indicate that PANi/In2O3 thin film gas sensor has good linear sensitive property to CH4 and CO, and is more sensitive to CH4, i.e., the sensitivity is 0.386Hz per ppm when the sensor is exposed to 500 ppm CH4 while only 0.16Hz per ppm to the same concentration of CO. Such sensitive properties of gas sensor in the constant concentration of CH4 at different temperature are also characterized. The result shows that temperature would affect the sensitive property of gas sensor.

  7. Dielectric tunability of vertically aligned ferroelectric-metal oxide nanocomposite films controlled by out-of-plane misfit strain

    Science.gov (United States)

    Wu, Huaping; Ma, Xuefu; Zhang, Zheng; Zhu, Jun; Wang, Jie; Chai, Guozhong

    2016-04-01

    A nonlinear thermodynamic model based on the vertically aligned nanocomposite (VAN) thin films of ferroelectric-metal oxide system has been developed to investigate the physical properties of the epitaxial Ba0.6Sr0.4TiO3 (BST) films containing vertical Sm2O3 (SmO) nanopillar arrays on the SrTiO3 substrate. The phase diagrams of out-of-plane lattice mismatch vs. volume fraction of SmO are calculated by minimizing the total free energy. It is found that the phase transformation and dielectric response of BST-SmO VAN systems are extremely dependent on the in-plane misfit strain, the out-of-plane lattice mismatch, the volume fraction of SmO phase, and the external electric field applied to the nanocomposite films at room temperature. In particular, the BST-SmO VAN systems exhibit higher dielectric properties than pure BST films. Giant dielectric response and maximum tunability are obtained near the lattice mismatch where the phase transition occurs. Under the in-plane misfit strain of umf=0.3 % and the out-of-plane lattice mismatch of u3=0.002 , the dielectric tunability can be dramatically enhanced to 90% with the increase of SmO volume fraction, which is well consistent with previous experimental results. This work represents an approach to further understand the dependence of physical properties on the lattice mismatch (in-plane and out-of-plane) and volume fraction, and to manipulate or optimize functionalities in the nanocomposite oxide thin films.

  8. Synthesis of a novel supermagnetic iron oxide nanocomposite hydrogel based on graft copolymerization of poly((2-dimethylamino)ethyl methacrylate) onto salep for controlled release of drug

    Energy Technology Data Exchange (ETDEWEB)

    Bardajee, Ghasem Rezanejade, E-mail: rezanejad@pnu.ac.ir; Hooshyar, Zari; Asli, Maryam Jahanbakhsh; Shahidi, Fatemeh Emamjome; Dianatnejad, Nastaran

    2014-03-01

    In this research, a novel supermagnetic iron oxide nanocomposite hydrogel was prepared using simultaneous in situ formation of iron oxide nanoparticles (IONs) and three-dimensional cross-linked polymer networks based on graft copolymerization of poly((2-dimethylamino)ethyl methacrylate) (PDMA) onto salep (PDMA-g-salep). The prepared ION–PDMA-g-salep hydrogel was systematically characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy with energy dispersive X-ray analysis (SEM–EDAX), transmission electron microscopy (TEM), thermal gravimetric analysis (TGA), X-ray diffraction (XRD), and vibrating sample magnetometer (VSM). In addition, the ION–PDMA-g-salep hydrogel exhibits favorable swelling properties that are sensitive to temperature, pH, and external magnetic field (EMF). The drug release behavior of the prepared hydrogel under EMF, different temperatures and pHs was also studied for the evaluation of the release mechanism and determination of diffusion coefficients. Finally, the antibacterial activity and cytotoxicity studies of the prepared hydrogel were examined. These results suggested that the ION–PDMA-g-salep hydrogel could be a promising candidate for biological dressing applications. - Highlights: • We introduce a novel biocompatible magnetic iron oxide nanocomposite hydrogel for controlled drug release. • We use a facile method to biocompatible magnetic iron oxide nanocomposite hydrogel. • We prepare magnetic iron oxide nanocomposite hydrogel with high pH, temperature, and magnetic field-sensitivity.

  9. The Influence of Irradiation and Accelerated Aging on the Mechanical and Tribological Properties of the Graphene Oxide/Ultra-High-Molecular-Weight Polyethylene Nanocomposites

    Directory of Open Access Journals (Sweden)

    Guodong Huang

    2016-01-01

    Full Text Available Graphene oxide/ultra-high-molecular-weight polyethylene (GO/UHMWPE nanocomposite is a potential and promising candidate for artificial joint applications. However, after irradiation and accelerated aging, the mechanical and tribological behaviors of the nanocomposites are still unclear and require further investigation. GO/UHMWPE nanocomposites were successfully fabricated using ultrasonication dispersion, ball-milling, and hot-pressing process. Then, the nanocomposites were irradiated by gamma ray at doses of 100 kGy. Finally, GO/UHMWPE nanocomposites underwent accelerated aging at 80°C for 21 days in air. The mechanical and tribological properties of GO/UHMWPE nanocomposites have been evaluated after irradiation and accelerated aging. The results indicated that the incorporation of GO could enhance the mechanical, wear, and antiscratch properties of UHMWPE. After irradiation, these properties could be further enhanced, compared to unirradiated ones. After accelerated aging, however, these properties have been significantly reduced when compared to unirradiated ones. Moreover, GO and irradiation can synergistically enhance these properties.

  10. Electrical and optical properties of reduced graphene oxide and multi-walled carbon nanotubes based nanocomposites: A comparative study

    Science.gov (United States)

    Goumri, Meryem; Lucas, Bruno; Ratier, Bernard; Baitoul, Mimouna

    2016-10-01

    Graphene and multi-walled carbon nanotubes have attracted interest for a number of potential applications. One of the most actively pursued applications uses graphene and carbon nanotubes as a transparent conducting electrode in solar cells, displays or touch screens. In this work, in situ reduced graphene oxide/Poly (vinyl alcohol) and multi-walled carbon nanotubes/Sodium Dodecyl Sulfate/Poly (vinyl alcohol) composites were prepared by water dispersion and different reduction treatments. Comparative studies were conducted to explore the electrical and optical properties of nanocomposites based on graphene and multi-walled carbon nanotubes. A thermal reduction of graphene oxide was more effective, producing films with sheet resistances as low as 102-103 Ω/square with 80% transmittance for 550 nm light. The percolation threshold of the thermally reduced graphene oxide composites (0.35 vol%) was much lower than that of the chemically reduced graphene oxide composites (0.57 vol%), and than that of the carbon nanotubes composites (0.47 vol%). The Seebeck coefficient of graphene oxide films changes from about 40 μV/K to -30 μV/K after an annealing of three hours at 200 °C. The optical absorption of the nanocomposites showed a high absorbance in near UV regions and the photoluminescence enhancement was achieved at 1 wt% graphene loading, while the carbon nanotubes based composite presents a significant emission at 0.7 wt% followed with a photoluminescence quenching at higher fraction of the nanofillers 1.6 wt% TRGO and 1 wt% MWCNTs.

  11. Green synthesis of layered 1T-MoS2/reduced graphene oxide nanocomposite with excellent catalytic performances for 4-nitrophenol reduction

    Science.gov (United States)

    Meng, Nannan; Cheng, Jian; Zhou, Yifeng; Nie, Wangyan; Chen, Pengpeng

    2017-02-01

    A green and facile process was developed to prepare layered octahedral phase MoS2/reduced graphene oxide (1T-MoS2/RGO) nanocomposite by a Vitamin C-assisted self-assemble method, in which graphene oxide (GO) and LiMoS2 were used as starting materials. Catalytic performances of 1T-MoS2/RGO were evaluated by hydrogenation of 4-nitrophenol (4-NP). It was demonstrated that the prepared 1T-MoS2/RGO nanocomposite presented excellent catalytic performance and cycling stability for 4-NP reduction, which made it a promising noble-metal-free catalyst. Additionally, broadening work suggested some other RGO-based metal nanocomposite with well-defined porous structure could be also generated via this facile self-assembly method.

  12. Applications of Metal/Mixed Metal Oxides as Photocatalyst: (A Review

    Directory of Open Access Journals (Sweden)

    Avnish Kumar Arora

    2016-08-01

    Full Text Available Metal oxides/ Mixed metal oxides have wide applications as catalyst, Adsorbents, Superconductors, semiconductors, ceramics, antifungal agents and also have spacious applications in medicines. This review article is focused on their applications as photocatalyst in various organic reactions.

  13. Methane combustion over lanthanum-based perovskite mixed oxides

    Energy Technology Data Exchange (ETDEWEB)

    Arandiyan, Hamidreza [New South Wales Univ., Sydney (Australia). School of Chemical Engineering

    2015-11-01

    This book presents current research into the catalytic combustion of methane using perovskite-type oxides (ABO{sub 3}). Catalytic combustion has been developed as a method of promoting efficient combustion with minimum pollutant formation as compared to conventional catalytic combustion. Recent theoretical and experimental studies have recommended that noble metals supported on (ABO{sub 3}) with well-ordered porous networks show promising redox properties. Three-dimensionally ordered macroporous (3DOM) materials with interpenetrated and regular mesoporous systems have recently triggered enormous research activity due to their high surface areas, large pore volumes, uniform pore sizes, low cost, environmental benignity, and good chemical stability. These are all highly relevant in terms of the utilization of natural gas in light of recent catalytic innovations and technological advances. The book is of interest to all researchers active in utilization of natural gas with novel catalysts. The research covered comes from the most important industries and research centers in the field. The book serves not only as a text for researcher into catalytic combustion of methane, 3DOM perovskite mixed oxide, but also explores the field of green technologies by experts in academia and industry. This book will appeal to those interested in research on the environmental impact of combustion, materials and catalysis.

  14. Biodiesel production from waste cooking oil using copper doped zinc oxide nanocomposite as heterogeneous catalyst.

    Science.gov (United States)

    Gurunathan, Baskar; Ravi, Aiswarya

    2015-01-01

    A novel CZO nanocomposite was synthesized and used as heterogeneous catalyst for transesterification of waste cooking oil into biodiesel using methanol as acyl acceptor. The synthesized CZO nanocomposite was characterized in FESEM with an average size of 80 nm as nanorods. The XRD patterns indicated the substitution of ZnO in the hexagonal lattice of Cu nanoparticles. The 12% (w/w) nanocatalyst concentration, 1:8 (v:v) O:M ratio, 55 °C temperature and 50 min of reaction time were found as optimum for maximum biodiesel yield of 97.71% (w/w). Hence, the use of CZO nanocomposite can be used as heterogeneous catalyst for biodiesel production from waste cooking oil. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Immobilization of glucoamylase on triazine-functionalized Fe3O4/graphene oxide nanocomposite: Improved stability and reusability.

    Science.gov (United States)

    Amirbandeh, Mahkameh; Taheri-Kafrani, Asghar

    2016-12-01

    Immobilization of an enzyme can enhance its catalytic activity, depending on the properties of the enzyme and the matrix. Graphene oxide is a nontoxic material and selective modulator for enzyme activity and is also a thermostable molecule that is important in large-scale nanostructure sheet applications. Herein, we have successfully developed a strategy for preparing a nanocomposite for enzyme immobilization model with high loading capacity. Nanostructures of hybrid graphene oxide-Fe3O4-cyanuric chloride (GO/MNP-CC) have adjustable surface chemistry that is an excellent candidate for covalent immobilization of enzymes. The morphology, structure and properties of GO/MNP-CC nanocomposite were investigated through different analytical tools. Glucoamylase, an important enzyme in industrial food products, was immobilized on GO/MNP-CC and exhibited excellent catalytic activity at pH 6.5 and 60°C. The results of this study indicated that the catalytic activity, reusability and stability of immobilized enzyme have been obviously improved compared to the free enzyme. The apparent Km and νmax for free and immobilized glucoamylase were also determined. These properties make them a good candidate to improve the practicality and further the development of the capacity enzyme attachment. Thus, the synthesized matrix has the potential for practical applications in other and binary enzyme immobilization and would have a wide prospect for their applications in bio-industry and biosensing.

  16. Aloe vera mediated hydrothermal synthesis of reduced graphene oxide decorated ZnO nanocomposite: Luminescence and antioxidant properties

    Science.gov (United States)

    Kavyashree, D.; Nagabhushana, H.; Ananda Kumari, R.; Basavaraj, R. B.; Suresh, D.; Daruka Prasad, B.; Sharma, S. C.

    2016-05-01

    A zinc oxide/reduced graphene oxide (ZnO/rGO) nanocomposite was fabricated by facile hydrothermal route using Aloe vera gel as surfactant. The PL emission spectrum of the ZnO/rGO composite consists of four peaks at around 380, 394, 449 and 465nm. The PL intensity is found to diminish in ZnO-rGO composites rather than in pure ZnO, which was attributed to electron transfer from ZnO to rGO. A single intense glow curve was recorded in rGo-ZnO for a dose range of 1-8kGy. The TL response curve of rGO-ZnO is found to be a simple glow curve structure, linear dependence over a dose range of 1-8kGy. The obtained ZnO/rGO composite could provide a facile and eco-friendly method for the development of graphene-based nanocomposites with promising applications in radiation dosimetry and antioxidant activities.

  17. Melting behavior of mixed U-Pu oxides under oxidizing conditions

    Science.gov (United States)

    Strach, Michal; Manara, Dario; Belin, Renaud C.; Rogez, Jacques

    2016-05-01

    In order to use mixed U-Pu oxide ceramics in present and future nuclear reactors, their physical and chemical properties need to be well determined. The behavior of stoichiometric (U,Pu)O2 compounds is relatively well understood, but the effects of oxygen stoichiometry on the fuel performance and stability are often still obscure. In the present work, a series of laser melting experiments were carried out to determine the impact of an oxidizing atmosphere, and in consequence the departure from a stoichiometric composition on the melting behavior of six mixed uranium plutonium oxides with Pu content ranging from 14 to 62 wt%. The starting materials were disks cut from sintered stoichiometric pellets. For each composition we have performed two laser melting experiments in pressurized air, each consisting of four shots of different duration and intensity. During the experiments we recorded the temperature at the surface of the sample with a pyrometer. Phase transitions were qualitatively identified with the help of a reflected blue laser. The observed phase transitions occur at a systematically lower temperature, the lower the Pu content of the studied sample. It is consistent with the fact that uranium dioxide is easily oxidized at elevated temperatures, forming chemical species rich in oxygen, which melt at a lower temperature and are more volatile. To our knowledge this campaign is a first attempt to quantitatively determine the effect of O/M on the melting temperature of MOX.

  18. Melting behavior of mixed U–Pu oxides under oxidizing conditions

    Energy Technology Data Exchange (ETDEWEB)

    Strach, Michal [CEA, DEN, DTEC, SECA, LCC, Cadarache F-13108, Saint-Paul-Lez-Durance (France); IM2NP, UMR CNRS 7334 – Aix Marseille University, Case 251, Avenue Escadrille Normandie Niemen, 13397 Marseille Cedex 20 (France); Manara, Dario [European Commission, Joint Research Centre, Institute for Transuranium Elements, P.O. Box 2340, 76125 Karlsruhe (Germany); Belin, Renaud C. [CEA, DEN, DTEC, SECA, LCC, Cadarache F-13108, Saint-Paul-Lez-Durance (France); Rogez, Jacques [IM2NP, UMR CNRS 7334 – Aix Marseille University, Case 251, Avenue Escadrille Normandie Niemen, 13397 Marseille Cedex 20 (France)

    2016-05-01

    In order to use mixed U–Pu oxide ceramics in present and future nuclear reactors, their physical and chemical properties need to be well determined. The behavior of stoichiometric (U,Pu)O{sub 2} compounds is relatively well understood, but the effects of oxygen stoichiometry on the fuel performance and stability are often still obscure. In the present work, a series of laser melting experiments were carried out to determine the impact of an oxidizing atmosphere, and in consequence the departure from a stoichiometric composition on the melting behavior of six mixed uranium plutonium oxides with Pu content ranging from 14 to 62 wt%. The starting materials were disks cut from sintered stoichiometric pellets. For each composition we have performed two laser melting experiments in pressurized air, each consisting of four shots of different duration and intensity. During the experiments we recorded the temperature at the surface of the sample with a pyrometer. Phase transitions were qualitatively identified with the help of a reflected blue laser. The observed phase transitions occur at a systematically lower temperature, the lower the Pu content of the studied sample. It is consistent with the fact that uranium dioxide is easily oxidized at elevated temperatures, forming chemical species rich in oxygen, which melt at a lower temperature and are more volatile. To our knowledge this campaign is a first attempt to quantitatively determine the effect of O/M on the melting temperature of MOX.

  19. Electrical and optical studies in polyaniline nanofibre–SnO2 nanocomposites

    Indian Academy of Sciences (India)

    Smritimala Sarmah; A Kumar

    2013-02-01

    Polyaniline nanofibre–tin oxide (PAni-SnO2) nanocomposites are synthesized and mixed with polyvinyl alcohol (PVA) as stabilizer to cast free-standing films. Composite films are characterized by X-ray diffraction studies (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), photoluminescence spectroscopy (PL) and UV-visible spectroscopy. XRD confirms the formation of PAni nanofibre–SnO2 nanocomposite. From TEM images, diameter of the polyaniline nanofibre and SnO2 nanoparticles in the PAni-SnO2 nanocomposite are found to be 20–60 nm. SEM results show fibrous morphology of the PAni nanofibre and spherical morphology of polyaniline-SnO2 composites. The nanocomposites exhibit high relative photoluminescence intensity in violet as well as green–yellow region of visible spectrum. From electrical conductivity measurement, it is confirmed that PAni nanofibre–SnO2 nanocomposite follows Mott’s one-dimensional variable range hopping (VRH) model.

  20. Ag-Ag2S/reduced graphene oxide hybrids used as long-wave UV radiation emitting nanocomposites

    Science.gov (United States)

    Li, Wenyao; Xu, Ruoyu; Ling, Min; He, Guanjie

    2017-10-01

    We report a facile thermal decomposition approach to synthesize Ag-Ag2S/reduced graphene oxide (Ag-Ag2S/rGO), the Ag-Ag2S nanoparticles uniformly dispersed on reduced graphene oxide with diameters of 10-20 nm. The photoluminescence spectra of Ag-Ag2S/rGO showed two obvious emission peaks at 327 and 339 nm with the excitation wavelength at 287 nm. Compared with Ag-Ag2S heterostructured clusters with two peaks at 407 and 430 nm, it showed a big blue shift and higher intensity, which makes it a novel candidate for long-wave UV radiation emitting nanocomposite.

  1. Non-electrolytic synthesis of copper oxide/carbon nanocomposite by surface plasma in super-dehydrated ethanol

    Science.gov (United States)

    Kozak, Dmytro S.; Sergiienko, Ruslan A.; Shibata, Etsuro; Iizuka, Atsushi; Nakamura, Takashi

    2016-02-01

    Electrolytic processes are widely used to synthesize different nanomaterials and it does not depend on what kind of the method has been applied (wet-chemistry, sonochemistry, plasma chemistry, electrolysis and so on). Generally, the reactions in the electrolyte are considered to be reduction/oxidation (REDOX) reactions between chemical reagents or the deposition of matter on the electrodes, in line with Faraday’s law. Due to the presence of electroconductive additives in any electrolyte, the polarization effect of polar molecules conducting an electrical current disappears, when external high-strength electric field is induced. Because initially of the charge transfer always belongs of electroconductive additive and it does not depend on applied voltage. The polarization of ethanol molecules has been applied to conduct an electric current by surface plasma interaction for the synthesis of a copper oxide/carbon nanocomposite material.

  2. Greener Route for Synthesis of aryl and alkyl-14H-dibenzo [a.j] xanthenes using Graphene Oxide-Copper Ferrite Nanocomposite as a Recyclable Heterogeneous Catalyst

    Science.gov (United States)

    Kumar, Aniket; Rout, Lipeeka; Achary, Lakkoji Satish Kumar; Dhaka, Rajendra. S.; Dash, Priyabrat

    2017-01-01

    A facile, efficient and environmentally-friendly protocol for the synthesis of xanthenes by graphene oxide based nanocomposite (GO-CuFe2O4) has been developed by one-pot condensation route. The nanocomposite was designed by decorating copper ferrite nanoparticles on graphene oxide (GO) surface via a solution combustion route without the use of template. The as-synthesized GO-CuFe2O4 composite was comprehensively characterized by XRD, FTIR, Raman, SEM, EDX, HRTEM with EDS mapping, XPS, N2 adsorption-desorption and ICP-OES techniques. This nanocomposite was then used in an operationally simple, cost effective, efficient and environmentally benign synthesis of 14H-dibenzo xanthene under solvent free condition. The present approach offers several advantages such as short reaction times, high yields, easy purification, a cleaner reaction, ease of recovery and reusability of the catalyst by a magnetic field. Based upon various controlled reaction results, a possible mechanism for xanthene synthesis over GO-CuFe2O4 catalyst was proposed. The superior catalytic activity of the GO-CuFe2O4 nanocomposite can be attributed to the synergistic interaction between GO and CuFe2O4 nanoparticles, high surface area and presence of small sized CuFe2O4 NPs. This versatile GO-CuFe2O4 nanocomposite synthesized via combustion method holds great promise for applications in wide range of industrially important catalytic reactions. PMID:28233832

  3. Greener Route for Synthesis of aryl and alkyl-14H-dibenzo [a.j] xanthenes using Graphene Oxide-Copper Ferrite Nanocomposite as a Recyclable Heterogeneous Catalyst

    Science.gov (United States)

    Kumar, Aniket; Rout, Lipeeka; Achary, Lakkoji Satish Kumar; Dhaka, Rajendra. S.; Dash, Priyabrat

    2017-02-01

    A facile, efficient and environmentally-friendly protocol for the synthesis of xanthenes by graphene oxide based nanocomposite (GO-CuFe2O4) has been developed by one-pot condensation route. The nanocomposite was designed by decorating copper ferrite nanoparticles on graphene oxide (GO) surface via a solution combustion route without the use of template. The as-synthesized GO-CuFe2O4 composite was comprehensively characterized by XRD, FTIR, Raman, SEM, EDX, HRTEM with EDS mapping, XPS, N2 adsorption-desorption and ICP-OES techniques. This nanocomposite was then used in an operationally simple, cost effective, efficient and environmentally benign synthesis of 14H-dibenzo xanthene under solvent free condition. The present approach offers several advantages such as short reaction times, high yields, easy purification, a cleaner reaction, ease of recovery and reusability of the catalyst by a magnetic field. Based upon various controlled reaction results, a possible mechanism for xanthene synthesis over GO-CuFe2O4 catalyst was proposed. The superior catalytic activity of the GO-CuFe2O4 nanocomposite can be attributed to the synergistic interaction between GO and CuFe2O4 nanoparticles, high surface area and presence of small sized CuFe2O4 NPs. This versatile GO-CuFe2O4 nanocomposite synthesized via combustion method holds great promise for applications in wide range of industrially important catalytic reactions.

  4. Structural investigation of SiSn/(reduced graphene oxide) nanocomposite powder for Li-ion battery anode applications

    Science.gov (United States)

    Kawasaki, Masahiro; Laokawee, Viratchara; Sarakonsri, Thapanee; Hashizume, Takashi; Shiojiri, Makoto

    2016-11-01

    We synthesized SiSn/(reduced graphene oxide (rGO)) nanocomposite powder for a Li-ion battery material and characterized the structure by transmission electron microscopy (TEM) and analytical scanning transmission electron microscopy (STEM). Graphene oxide was prepared by Hummers method. The graphene oxide powder processed by heat treatment was added together with Si powder into a solution of SnCl2 ṡ 2(H2O) dissolved in N2 bubbled ethylene glycol, and the solution was reacted with NaBH4. The product had a nominal atomic ratio of Si: Sn: C = 14: 3.5: 100. High-resolution TEM/STEM analysis revealed that the powder consisted of crystalline particles of Sn, Si, and SiO as well as thin reduced graphene oxide (rGO) lamellae of amorphous-like graphite with distorted lattices that were often found in areas as local as a few nm2. The aggregated Si and SiO particles grew up to several hundred nm across. Sn particles grew as large as a few tens of nm while those as small as a few nm were scattered on the (0001) rGO surface with some epitaxial relations. Si, SiO, and Sn particles were found hanging on at the edges of the rGO lamellae. An electrochemical test was performed for this nanocomposite powder. The result suggested that the SiSn/rGO powder would be a promising anode material for lithium-ion batteries with high capacity.

  5. Efficiency Enhancement in Bulk Heterojunction Polymer Photovoltaic Cells Using ZrTiO4/Bi2O3 Metal-Oxide Nanocomposites

    DEFF Research Database (Denmark)

    Abdul Jabbar, Mohammed Hussain; Neppolian, B.; Shim, Hee-Sang

    2010-01-01

    We report the effect of metal-oxide nanocomposites on the performance of bulk heterojunction polymer solar cells. A photoactive layer composed of poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) was blended with a newly developed ZrTiO4/Bi2O3 (BITZ) metal...

  6. Solar absorption and thermal emission properties of multiwall carbon nanotube/nickel oxide nanocomposite thin films synthesized by sol-gel process

    CSIR Research Space (South Africa)

    Roro, Kittessa T

    2012-05-01

    Full Text Available Multiwall carbon nanotubes (MWCNTs)/nickel oxide (NiO) nanocomposites were successfully prepared by a sol–gel process and coated on an aluminium substrate. The MWCNTs were chemically functionalized and then added into NiO alcogels, and magnetic...

  7. High-performance towards removal of toxic hexavalent chromium from aqueous solution using graphene oxide-alpha cyclodextrin-polypyrrole nanocomposites

    CSIR Research Space (South Africa)

    Chauke, VP

    2015-07-01

    Full Text Available Graphene oxide (GO) was functionalized with alpha cyclodextrin (aCD) through a covalent bond to form GO-aCD nanocomposites (NC). GO-aCD NC was further modified with polypyrrole (PPY) to afford an advanced GO-aCD-PPY NC for the removal of highly...

  8. Rare earth ions doped polyaniline/cobalt ferrite nanocomposites via a novel coordination-oxidative polymerization-hydrothermal route: Preparation and microwave-absorbing properties

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Chunming; Jiang, Junjun; Liu, Xiaohua; Yin, Chengjie; Deng, Cuifen

    2016-04-15

    Polyaniline/CoRE{sub x}Fe{sub 2−x}O{sub 4} (RE=La, Ce, Y, x=0.05–0.25) nanocomposites were successfully synthesized by a novel coordination-oxidative polymerization-hydrothermal method, and doped by sulfosalicylic acid. The resultant nanocomposites were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), vibrating sample magnetometer (VSM) and electromagnetic measurements. The composites mainly showed nanofibers with a diameter of ca. 70 nm and a length longer than 2 μm. The surface of composites was uniformly covered with numerous nanoparticles with an average size of ca. 10–20 nm. Microwave absorption properties of polyaniline/CoRE{sub x}Fe{sub 2−x}O{sub 4} nanocomposites doped with La ion were found to be better than those doped with Ce and Y ions. For the polyaniline/CoLa{sub x}Fe{sub 2−x}O{sub 4} nanocomposite, the optimal microwave absorption performance is at x=0.15, that is, the mass ratio of La in CoLa{sub x}Fe{sub 2−x}O{sub 4} is 7.5%, with the conductivity of the composite about 0.833 S/cm. Furthermore, when the layer thickness is 2 mm, the maximum reflection loss achieves the maximum number of −42.65 dB at 15.91 GHz with a bandwidth of 6.14 GHz above −10 dB loss, suggesting that these nanocomposites are excellent in microwave absorbing capacity. - Graphical abstract: Scheme PAn/CoRE{sub x}Fe{sub 2−x}O{sub 4} nanocomposites prepared via a novel coordination-oxidative polymerization-hydrothermal route. - Highlights: • An organic–inorganic hybrid―polyaniline/CoRE{sub x}Fe{sub 2−x}O{sub 4} (RE=La, Ce, Y, x=0.05–0.25) nanocomposites was prepared via a novel coordination-oxidative polymerization-hydrothermal route. • The as-prepared polyaniline/CoRE{sub x}Fe{sub 2−x}O{sub 4} nanocomposites exhibit excellent microwave absorbing performance compared with the composites prepared by using conventional method. • The novel method reported in this work could

  9. Highly stable, mesoporous mixed lanthanum-cerium oxides with tailored structure and reducibility

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Shuang; Broitman, Esteban; Wang, Yanan; Cao, Anmin; Veser, Goetz

    2011-05-01

    Pure and mixed lanthanum and cerium oxides were synthesized via a reverse microemulsion-templated route. This approach yields highly homogeneous and phase-stable mixed oxides with high surface areas across the entire range of La:Ce ratios from pure lanthana to pure ceria. Surprisingly, all mixed oxides show the fluorite crystal structure of ceria, even for lanthanum contents as high as 90%. Varying the La:Ce ratio not only allows tailoring of the oxide morphology (lattice parameter, pore structure, particle size, and surface area), but also results in a fine-tuning of the reducibility of the oxide which can be explained by the creation of oxygen vacancies in the ceria lattice upon La addition. Such finely controlled syntheses, which enable the formation of stable, homogeneous mixed oxides across the entire composition range, open the path towards functional tailoring of oxide materials, such as rational catalyst design via fine-tuning of redox activity.

  10. Thermal Stability and Oxidation Resistance of Nanocomposite TiC/a-C Protective Coatings

    NARCIS (Netherlands)

    Martinez-Martinez, Diego; Lopez-Cartes, Carlos; Gago, Raul; Fernandez, Asuncion; Carlos Sanchez-Lopez, Juan

    2009-01-01

    Nanocomposite films composed by small crystallites of hard phases embedded in an amorphous lubricant matrix have been extensively studied as protective coatings. These kinds of coatings have often to work in extreme environments, exposed to high temperatures (above 800-900 degrees C), and/or oxidizi

  11. Manufacturing of multilayer graphene oxide/poly(ethylene terephthalate) nanocomposites with tunable crystallinity, chain orientations and thermal transitions

    Energy Technology Data Exchange (ETDEWEB)

    Seyyed Monfared Zanjani, Jamal [Faculty of Engineering and Natural Sciences, Sabanci University, Orhanli, 34956 Tuzla, Istanbul (Turkey); Saner Okan, Burcu, E-mail: bsanerokan@sabanciuniv.edu [Sabanci University Nanotechnology Research and Application Center, SUNUM, Orhanli, 34956 Tuzla, Istanbul (Turkey); Nanografen Nanotechnological Products Limited Company, GOSB Teknopark, Gebze 41430, Kocaeli (Turkey); Menceloglu, Yusuf [Faculty of Engineering and Natural Sciences, Sabanci University, Orhanli, 34956 Tuzla, Istanbul (Turkey); Nanografen Nanotechnological Products Limited Company, GOSB Teknopark, Gebze 41430, Kocaeli (Turkey)

    2016-06-15

    Thermally exfoliated graphene oxide (TEGO) reinforced polyethylene terephthalate (PET) nanocomposites with controlled crystallinity, chain conformations and thermo-mechanical properties were produced with very low TEGO weight fractions by a twin-screw compounding extruder. Tensile modulus was found to increase by 52% by the addition of 1 wt% TEGO. This significant increase in mechanical properties of PET nanocomposites was explained by well intercalation of PET chains through multi-layer graphene sheets and complete coverage of graphene surface by electrostatic interactions. An increase in the ratio of gauche and trans conformations in PET chains indicated that PET nanocomposites became more crystalline by increasing TEGO amount. Transmission electron microscopy observations showed the favorable interaction between TEGO sheets and PET matrix facilitating the dispersion and flattening of graphene sheets into polymeric matrix during elongation. The integration of 1 wt% TEGO sheets into PET matrix enhanced heat distortion temperature from 71 °C for neat specimen upto 91.6 °C at the constant stress of 0.45 MPa, and increased Vicat softening point from 76 °C upto 95 °C. Therefore, the failures of PET considerably reduced by improving short-term heat resistance and its softening properties between glass transition temperature and melting temperature by the incorporation of TEGO sheets. - Highlights: • 52% modulus improvement by the addition of 1 wt% graphene in PET. • Well-intercalation of PET chains through graphene sheets during compounding process. • Homogeneous graphene dispersion by favorable interactions between graphene and PET. • Enhancement in Heat distortion temperature and Vicat softening point of PET composite. • Considerable reduction in failures of PET by improving short-term heat resistance.

  12. Polyaniline–bismuth oxide nanocomposite sensor for quantification of anti-parkinson drug pramipexole in solubilized system

    Energy Technology Data Exchange (ETDEWEB)

    Jain, Rajeev, E-mail: rajeevjain54@yahoo.co.in [School of Studies in Chemistry, Jiwaji University, Gwalior, 474011 (India); Tiwari, Dinesh Chandra [School of Studies in Physics, Jiwaji University, Gwalior, 474011 (India); Shrivastava, Swati [School of Studies in Chemistry, Jiwaji University, Gwalior, 474011 (India)

    2014-07-01

    Graphical abstract: - Highlights: • PANI–Bi{sub 2}O{sub 3} nanocomposite has been synthesized first time and effectively used for the electrochemical studies. • PANI–Bi{sub 2}O{sub 3}/GCE modified sensors have a large surface area greatly enhancing the sensitivity of electroactive species. • Modified sensor was successfully used for the detection of pramipexole utilizing enhancement effect of surfactant. • The reported method showed very good stability as well as reproducibility for the voltammetric analysis of pramipexole. - Abstract: In this study, a new sensor polyaniline–bismuth oxide (PANI–Bi{sub 2}O{sub 3}) nanocomposite has been fabricated and characterized by cyclic voltammetry (CV), scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS). SEM was used to provide information about the morphology of the PANI–Bi{sub 2}O{sub 3} nanocomposite. Cyclic voltammetric studies of electroactive species i.e. K{sub 3}Fe(CN){sub 6} demonstrate almost reversible electrochemical behaviour, with diffusion controlled mass transfer process in the double layer region of the electrode. EIS studies revealed that PANI–Bi{sub 2}O{sub 3}/GCE having lower charge transfer resistance which leads to higher electrocatalytic activity. This modified electrode was successfully used for the detection of pramipexole in pharmaceutical formulation in sodium lauryl sulphate (SLS) in Britton Robinson (BR) buffer at pH 4.5. The ease of fabrication, excellent electrochemical performance and high electroactive surface area are the promising features of the fabricated sensor.

  13. Selective oxidation of propane to acrylic acid over mixed metal oxide catalysts

    Institute of Scientific and Technical Information of China (English)

    Wei Zheng; Zhenxing Yu; Ping Zhang; Yuhang Zhang; Hongying Fu; Xiaoli Zhang; Qiquan Sun; Xinguo Hu

    2008-01-01

    The effects of metal atomic ratio, water content, oxygen content, and calcination temperature on the catalytic perfor-mances of MoVTeNbO mixed oxide catalyst system for the selective oxidation of propane to acrylic acid have been investigated and discussed. Among the catalysts studied, it was found that the MoVTeNbO catalyst calcined at a temperature of 600 ℃ showed the best performance in terms of propane conversion and selectivity for acrylic acid under an atmosphere of nitrogen. An effective MoVTeNbO oxide catalyst for propane selective oxidation to acrylic acid was obtained with a combination of a preferred metal atomic ratio (Mo1 V0.31Te0.23Nb0.12). The optimum reaction condition for the selective oxidation of propane was the molar ratio of C3H81 :O2 : H2O : N1 = 4.4 : 12.8 : 15.3 : 36.9. Under such conditions, the conversion of propane and the maximum yield of acrylic acid reached about 50% and 21%, respectively.

  14. Different Abilities of Eight Mixed Cultures of Methane-oxidizing Bacteria to Degrade TCE

    DEFF Research Database (Denmark)

    Broholm, Kim; Christensen, Thomas Højlund; Jensen, Bjørn K.

    1993-01-01

    The ability of eight mixed cultures of methane-oxidizing bacteria to degrade trichloroethylene (TCE) was examined in laboratory batch experiments. This is one of the first reported works studying TCE degradation by mixed cultures of methane-oxidizing bacteria at 10°C, a common temperature for soils...

  15. 76 FR 65544 - Standard Format and Content of License Applications for Mixed Oxide Fuel Fabrication Facilities

    Science.gov (United States)

    2011-10-21

    ... issuance of the guide (74 FR 36780). The comment period closed on September 21, 2009. The staff's responses... COMMISSION Standard Format and Content of License Applications for Mixed Oxide Fuel Fabrication Facilities... Format and Content of License Applications for Mixed Oxide Fuel Fabrication Facilities.'' This...

  16. Incorporation, oxidation and pyrolysis of ferrocene into porous silica glass: a route to different silica/carbon and silica/iron oxide nanocomposites.

    Science.gov (United States)

    Schnitzler, Mariane C; Mangrich, Antônio S; Macedo, Waldemar A A; Ardisson, José D; Zarbin, Aldo J G

    2006-12-25

    This work reports the incorporation of ferrocene into a porous silica glass under ambient temperature and atmosphere. After or during the ferrocene incorporation, the spontaneous formation of ferricinium ions was observed by electron paramagnetic resonance (EPR), UV-visible, X-ray absorption near-edge structure (XANES), and 57Fe Mössbauer measurements. It was shown that the oxidation of ferrocene molecules to ferricinium ions was promoted by air and that the Si-O- groups on the surface of the pores act as counteranions. Pyrolysis of the porous glass/ferricinium material under argon atmosphere and variable temperature yields different glass/carbon nanocomposites, which were subsequently treated with an HF solution in order to remove the glassy fraction. The resulting insoluble carbon materials were characterized by transmission electron microscopy (TEM), Raman, and EPR spectroscopy and consisted of amorphous carbon when the pyrolysis was carried out at 900 or 1000 degrees C and of a mixture of carbon nanotubes and carbonaceous materials at a pyrolysis temperature of 1100 degrees C. When the pyrolysis was conducted under air, the incorporated ferricinium forms alpha-Fe2O3, and the resulting material is a transparent and highly homogeneous glass/iron oxide nanocomposite.

  17. Understanding the electrochemical mechanism of the core-shell ceria-LiZnO nanocomposite in a low temperature solid oxide fuel cell

    OpenAIRE

    2014-01-01

    Ceria based solid solutions have been considered some of the best candidates to develop intermediate/low temperature solid oxide fuel cells (IT/LT-SOFCs, 600-800 degrees C). However, the barrier to commercialization has not been overcome even after numerous research activities due to its inherent electronic conduction in a reducing atmosphere and inadequate ionic conductivity at low temperatures. The present work reports a new type of all-oxide nanocomposite electrolyte material based on a se...

  18. Co-Al Mixed Oxides Prepared via LDH Route Using Microwaves or Ultrasound: Application for Catalytic Toluene Total Oxidation

    Directory of Open Access Journals (Sweden)

    Eric Genty

    2015-05-01

    Full Text Available Co6Al2HT hydrotalcite-like compounds were synthesized by three different methods: co-precipitation, microwaves-assisted and ultrasound-assisted methods. The mixed oxides obtained after calcination were studied by several techniques: XRD, TEM, H2-TPR and XPS. They were also tested as catalysts in the reaction of total oxidation of toluene. The physico-chemical studies revealed a modification of the structural characteristics (surface area, morphology as well as of the reducibility of the formed mixed oxides. The solid prepared by microwaves-assisted synthesis was the most active. Furthermore, a relationship between the ratio of Co2+ on the surface, the reducibility of the Co-Al mixed oxide and the T50 in toluene oxidation was demonstrated. This suggests a Mars Van Krevelen mechanism for toluene total oxidation on these catalysts.

  19. Novel mesoporous mixed Nb-M (M = V, Mo, and Sb) oxides for oxidative dehydrogenation of propane.

    Science.gov (United States)

    Yuan, Li; Bhatt, Salil; Beaucage, Gregory; Guliants, Vadim V; Mamedov, Sergey; Soman, Rajiv S

    2005-12-15

    Novel thermally stable mesoporous mixed metal Nb-M (M = V, Mo and Sb) oxides were synthesized in the presence of a nonionic Pluronic P123 surfactant. These oxides displayed promising pore structures and chemical compositions for selective oxidative functionalization of propane: high surface areas (up to 200 m2/g), large pore sizes (5-14 nm), and high pore volumes (up to 0.46 cm3/g). The oxidative dehydrogenation of propane to propylene over mesoporous mixed metal Nb-M oxides employed as a probe reaction suggested that the M component was dispersed as the molecular surface species and also formed a solid solution with NbOx in the inorganic walls of these mesoporous mixed metal oxides.

  20. Ag-loaded TiO2/reduced graphene oxide nanocomposites for enhanced visible-light photocatalytic activity

    Science.gov (United States)

    Vasilaki, E.; Georgaki, I.; Vernardou, D.; Vamvakaki, M.; Katsarakis, N.

    2015-10-01

    In this work, Ag nanoparticles were loaded by chemical reduction onto TiO2 P25 under different loadings ranging from 1 up to 4 wt% and hydrothermally deposited on reduced graphene oxide sheets. Chemical reduction was determined to be an effective preparation approach for Ag attachment to titania, leading to the formation of small silver nanoparticles with an average diameter of 4.2 nm. The photocatalytic performance of the hybrid nanocomposite materials was evaluated via methylene blue (MB) dye removal under visible-light irradiation. The rate of dye decolorization was found to depend on the metal loading, showing an increase till a threshold value of 3 wt%, above which the rate drops. Next, the as prepared sample of TiO2/Ag of better photocatalytic response, i.e., at a 3 wt% loading value, was hydrothermally deposited on a platform of reduced graphene oxide (rGO) of tunable content (mass ratio). TiO2/Ag/rGO coupled nanocomposite presented significantly enhanced photocatalytic activity compared to the TiO2/Ag, TiO2/rGO composites and bare P25 titania semiconductor photocatalysts. In particular, after 45 min of irradiation almost complete decolorization of the dye was observed for the TiO2/Ag/rGO nanocatalyst, while the respective removal efficiency was 92% for TiO2/Ag, 93% for TiO2/rGO and only 80% for the bare TiO2 nanoparticles. This simple step by step preparation strategy allows for optimum exploitation of the advanced properties of metal plasmonic effect and reduced graphene oxide as the critical host for boosting the overall photocatalytic activity towards visible-light.

  1. Preparation of Mixed Perovskite Oxides for Blue-Green Lasers

    Science.gov (United States)

    1984-02-01

    higher for oxide or fluoride . 𔃽. A high radiative lifetime and high fluorescent quantum yield for Ce or the rare earth are desirable. 3 + 4...for all of our single crystal -4- preparations are lanthanum oxide (La„0 ), aluminum oxide (Al^O^) , scandium oxide (Sc„0-.) , and cerium oxide (Ce...crystal material is highly important. Ideally, oxides should be grown in O2, fluorides in ?„, and so forth in order to prevent defects such as

  2. Characterisation of Fe-Cr-Al mixed oxides

    Energy Technology Data Exchange (ETDEWEB)

    Gallardo Amores, J.M. [Universidad Complutense de Madrid (Spain). Dept. de Quimica Inorg.; Sanchez Escribano, V. [Departamento de Quimica Inorganica, Universidad, Salamanca (Spain); Busca, G. [Istituto di Chimica, Facolta di Ingegneria, Universita, P.le J.F. Kennedy, I-16129, Genova (Italy)

    1999-08-16

    Several samples of iron chromium aluminium mixed oxides with different composition have been prepared by coprecipitation at controlled pH starting from the corresponding nitrate salts and following dried at 393 K and calcination at 673 K for 3 h and 1173 K for 3 h. The powders have been characterised by XRD, FT-IR and DR UV-Vis spectroscopies, DTA-TG thermal analyses and measurements of BET surface area. It has been found alumina is soluble into {alpha}-FeCrO{sub 3} phase up to near 20%. These samples are stable at 1243 K with a relative high specific surface area. The {gamma},{theta}{yields}{alpha} phase transition is shifted towards higher temperatures by increasing Al content, being not detectable when {alpha}-FeCrO{sub 3} phase is the main phase. Surface chromates species are identified by the different techniques used and their amount seem to depend directly on the specific surface area of each sample. (orig.) 36 refs.

  3. Carbon nanotubes-ionic liquid nanocomposites sensing platform for NADH oxidation and oxygen, glucose detection in blood.

    Science.gov (United States)

    Bai, Lu; Wen, Dan; Yin, Jianyuan; Deng, Liu; Zhu, Chengzhou; Dong, Shaojun

    2012-03-15

    An excellent electrochemical sensing platform has been designed by combining the huge specific surface area of carbon nanotubes (CNTs) and the remarkable conductivity of ionic liquid (IL). IL can easily untangle CNTs bundles and disperse CNTs by itself under grinding condition due to the π-π interaction between CNTs and IL. The resulting nanocomposites showed an augmentation on the voltammetric and amperometric behaviors of electrocatalytic activity toward O(2) and NADH. Therefore, such an efficient platform was developed to fabricate mediator-free oxygen sensor and glucose biosensor based on glucose dehydrogenase (GDH). O(2) could be determined in the range of zero to one hundred percent of O(2) content with the detection limit of 126 μg L(-1) (S/N=3). The glucose biosensor which was constructed by entrapping GDH into chitosan on the nanocomposites modified glassy carbon electrode surface, exhibited good electrocatalytic oxidation toward glucose with a detection limit of 9 μM in the linear range of 0.02-1mM. We also applied the as-prepared sensors to detect oxygen and glucose in real blood samples and acquired satisfied results. Copyright © 2012 Elsevier B.V. All rights reserved.

  4. Controlling interlayer interactions in vanadium pentoxide-poly(ethylene oxide) nanocomposites for enhanced magnesium-ion charge transport and storage

    Science.gov (United States)

    Perera, Sanjaya D.; Archer, Randall B.; Damin, Craig A.; Mendoza-Cruz, Rubén; Rhodes, Christopher P.

    2017-03-01

    Rechargeable magnesium batteries provide the potential for lower cost and improved safety compared with lithium-ion batteries, however obtaining cathode materials with highly reversible Mg-ion capacities is hindered by the high polarizability of divalent Mg-ions and slow solid-state Mg-ion diffusion. We report that incorporating poly(ethylene oxide) (PEO) between the layers of hydrated vanadium pentoxide (V2O5) xerogels results in significantly improved reversible Mg-ion capacities. X-ray diffraction and high resolution transmission electron microscopy show that the interlayer spacing between V2O5 layers was increased by PEO incorporation. Vibrational spectroscopy supports that the polymer interacts with the V2O5 lattice. The V2O5-PEO nanocomposite exhibited a 5-fold enhancement in Mg-ion capacity, improved stability, and improved rate capabilities compared with V2O5 xerogels. The Mg-ion diffusion coefficient of the nanocomposite was increased compared with that of V2O5 xerogels which is attributed to enhanced Mg-ion mobility due to the shielding interaction of PEO with the V2O5 lattice. This study shows that beyond only interlayer spacing, the nature of interlayer interactions of Mg-ions with V2O5, PEO, and H2O are key factors that affect Mg-ion charge transport and storage in layered materials. The design of layered materials with controlled interlayer interactions provides a new approach to develop improved cathodes for magnesium batteries.

  5. Electrophoretic-deposited novel ternary silk fibroin/graphene oxide/hydroxyapatite nanocomposite coatings on titanium substrate for orthopedic applications

    Science.gov (United States)

    Li, Ming; Xiong, Pan; Mo, Maosong; Cheng, Yan; Zheng, Yufeng

    2016-09-01

    The combination of graphene oxide (GO) with robust mechanical property, silk fibroin (SF) with fascinating biological effects and hydroxyapatite (HA) with superior osteogenic activity is a competitive approach to make novel coatings for orthopedic applications. Herein, the feasibility of depositing ternary SF/GO/HA nanocomposite coatings on Ti substrate was firstly verified by exploiting electrophoretic nanotechnology, with SF being used as both a charging additive and a dispersion agent. The surface morphology, microstructure and composition, in vitro hemocompatibility and in vitro cytocompatibility of the resulting coatings were investigated by SEM, Raman, FTIR spectra and biocompatibility tests. Results demonstrated that GO, HA and SF could be co-deposited with a uniform, smooth thin-film morphology. The hemolysis rate analysis and the platelet adhesion test indicated good blood compatibility of the coatings. The human osteosarcoma MG63 cells displayed well adhesion and proliferation behaviors on the prepared coatings, with enhanced ALP activities. The present study suggested that SF/GO/HA nanocomposite coatings could be a promising candidate for the surface functionalization of biomaterials, especially as orthopedic implant coating.

  6. A novel nonenzymatic biosensor for evaluation of oxidative stress based on nanocomposites of graphene blended with CuI.

    Science.gov (United States)

    Li, Changhui; Liu, Xiaoli; Zhang, Yuanyuan; Chen, Yun; Du, Tianyu; Jiang, Hui; Wang, Xuemei

    2016-08-24

    A high-sensitive nonenzymatic hydrogen peroxide (H2O2) biosensor based on cuprous iodide and graphene (CuI/Gr) composites has been explored for the detection of H2O2 released by living cells and monitoring the oxidative stress of cells under excellular stimulation. The biosensor properties were evaluated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), amperometric i-t curve, and the redox-competition mode of scanning electrochemical microscopy (SECM). Our observations demonstrate that the CuI/Gr nanocomposites modified glassy carbon electrode (GCE) exhibits excellent catalytic activity for H2O2 with relatively low detection limit and a wide linear range from 0.5 μM to 3 mM. Moreover, the redox-competition mode of SECM imaging study further illustrates the improved electrochemical catalytic capability for H2O2 reduction with CuI/Gr nanocomposites deposited on graphite electrode. Hence, the as-prepared nonenzymatic H2O2 biosensor could be used to detect H2O2 release from different kinds of living cells under stimulation while eliminating the interference of ascorbic acid.

  7. Comparison study on photocatalytic oxidation of pharmaceuticals by TiO{sub 2}-Fe and TiO{sub 2}-reduced graphene oxide nanocomposites immobilized on optical fibers

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Lu; Wang, Huiyao, E-mail: huiyao@nmsu.edu; Jiang, Wenbin; Mkaouar, Ahmed Radhi; Xu, Pei, E-mail: pxu@nmsu.edu

    2017-07-05

    Highlights: • Incorporating rGO or Fe{sup 3+} ions in TiO{sub 2} photocatalyst could enhance photocatalysis. • TiO{sub 2}-rGO exhibited higher photocatalytic activity under UV irradiation. • TiO{sub 2}-Fe demonstrated more suitable for visible light irradiation. • Reduced recombination rate contributed to enhanced photocatalysis of TiO{sub 2}-rGO. • Narrower band gap accounted for increased photocatalytic activity of TiO{sub 2}-Fe. - Abstract: Incorporating reduced graphene oxide (rGO) or Fe{sup 3+} ions in TiO{sub 2} photocatalyst could enhance photocatalytic degradation of organic contaminants in aqueous solutions. This study characterized the photocatalytic activities of TiO{sub 2}-Fe and TiO{sub 2}-rGO nanocomposites immobilized on optical fibers synthesized by polymer assisted hydrothermal deposition method. The photocatalysts presented a mixture phase of anatase and rutile in the TiO{sub 2}-rGO and TiO{sub 2}-Fe nanocomposites. Doping Fe into TiO{sub 2} particles (2.40 eV) could reduce more band gap energy than incorporating rGO (2.85 eV), thereby enhancing utilization efficiency of visible light. Incorporating Fe and rGO in TiO{sub 2} decreased significantly the intensity of TiO{sub 2} photoluminescence signals and enhanced the separation rate of photo-induced charge carriers. Photocatalytic performance of the synthesized nanocomposites was measured by the degradation of three pharmaceuticals under UV and visible light irradiation, including carbamazepine, ibuprofen, and sulfamethoxazole. TiO{sub 2}-rGO exhibited higher photocatalytic activity for the degradation of pharmaceuticals under UV irradiation, while TiO{sub 2}-Fe demonstrated more suitable for visible light oxidation. The results suggested that the enhanced photocatalytic performance of TiO{sub 2}-rGO could be attributed to reduced recombination rate of photoexcited electrons-hole pairs, but for TiO{sub 2}-Fe nanocomposite, narrower band gap would contribute to increased photocatalytic

  8. NIR Light-, Temperature-, pH-, and Redox-Responsive Polymer-Modified Reduced Graphene Oxide/Mesoporous Silica Sandwich-Like Nanocomposites for Controlled Release.

    Science.gov (United States)

    Wang, Panjun; Chen, Shuo; Cao, Ziquan; Wang, Guojie

    2017-08-30

    Here a novel quadruple-responsive nanocarrier based on reduced graphene oxide/mesoporous silica sandwich-like nanocomposites (rGO@MS) modified by pH- and temperature-responsive poly(N,N-dimethylaminoethyl methacrylate) (PDMAEMA) with a linker of disulfide was constructed via surface-initiated atom transfer radical polymerization. The polymer chains would be used as gatekeepers to control the release of the loaded cargo molecules under pH, temperature, NIR light and redox stimuli. The cargo molecules (rhodamine B) were demonstrated to release from the polymer-modified nanocomposites triggered by the quadruple-stimuli. It is noted that the release of the loaded rhodamine B from the nanocarriers could be enhanced greatly under the synergistic effect of multiple stimuli. The prepared quadruple-responsive polymer-modified nanocomposites show a bright prospect in the field of smart nanocarriers for controlled release.

  9. Superior electrochemical properties of manganese dioxide/reduced graphene oxide nanocomposites as anode materials for high-performance lithium ion batteries

    Science.gov (United States)

    Lee, Suk-Woo; Lee, Chang-Wook; Yoon, Seung-Beom; Kim, Myeong-Seong; Jeong, Jun Hui; Nam, Kyung-Wan; Roh, Kwang Chul; Kim, Kwang-Bum

    2016-04-01

    MnO2/reduced graphene oxide (rGO) nanocomposites were synthesized via a simple solution method at room temperature for use in Li-ion batteries. Owing to the mesoporous features as well as the high electrical conductivity of rGO, the overall electronic and ionic conductivities of the nanocomposite were increased, resulting in improved electrochemical properties in terms of specific capacity, rate capability, and cyclability. In particular, as-prepared nanocomposites showed 222 and 115 mAh g-1 at a current density of as high as 5 and 10 A g-1, and the specific capacitance was well maintained after 400 cycles. In addition, MnO2, via composite formation with rGO, permitted the additional conversion reaction between MnO and Mn3O4, resulting in the reduction of the initial irreversible capacity despite the high first discharge capacity caused by the large specific surface area.

  10. Dielectric properties and structural dynamics of melt compounded hot-pressed poly(ethylene oxide)–organophilic montmorillonite clay nanocomposite films

    Indian Academy of Sciences (India)

    R J Sengwa; Shobhna Choudhary

    2012-02-01

    The dielectric properties of melt compounded hot-pressed nanocomposite films consisting of a poly(ethylene oxide) (PEO) and organophilic montmorillonite (OMMT) clay surface modified with trimethyl stearyl ammonium as filler with increasing amount up to 20 wt.% OMMT were investigated in a frequency range of 20 Hz–1 MHz at 30 °C. The predominance of OMMT exfoliated structures in PEO–OMMT nanocomposites were recognized by a decrease of the real part of complex dielectric function. OMMT concentration dependent dielectric and electric modulus relaxation times have revealed that the interactions compatibility between PEO molecules and dispersed OMMT nano-platelets in PEO matrix governs the PEO segmental dynamics. A.C. conductivity of these nanocomposites increases by two orders of magnitude in the experimental frequency range.

  11. Sol-gel derived oxides and mixed oxides catalysts with narrow mesoporous distribution

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A novel sol-gel process for preparing oxides and mixed oxides sols from precipitation and peptization process is reported in this article. Inorganic salts are used as raw materials in this study. It is found that the amount of acid has great influence on the stability and particle diameter distribution of the precursor sols. Ultrasonic treatment is used to prepare alumina sol at room temperature. The result of 27Al NMR shows that there exist Al137+ species in the sol. By controlling the sol particles with narrow particle diameter distribution, alumina, titania and silica-alumina (SA) materials with narrow mesoporous distribution are formed by regular packing of sol particles during gelation without using any templates. The results also show that the structure and particle diameter distribution of precursor sol determine the final materials' texture.

  12. Investigation of the Carbon Monoxide Gas Sensing Characteristics of Tin Oxide Mixed Cerium Oxide Thin Films

    Directory of Open Access Journals (Sweden)

    Muhammad B. Haider

    2012-02-01

    Full Text Available Thin films of tin oxide mixed cerium oxide were grown on unheated substrates by physical vapor deposition. The films were annealed in air at 500 °C for two hours, and were characterized using X-ray photoelectron spectroscopy, atomic force microscopy and optical spectrophotometry. X-ray photoelectron spectroscopy and atomic force microscopy results reveal that the films were highly porous and porosity of our films was found to be in the range of 11.6–21.7%. The films were investigated for the detection of carbon monoxide, and were found to be highly sensitive. We found that 430 °C was the optimum operating temperature for sensing CO gas at concentrations as low as 5 ppm. Our sensors exhibited fast response and recovery times of 26 s and 30 s, respectively.

  13. A novel high-performance supercapacitor based on high-quality CeO2/nitrogen-doped reduced graphene oxide nanocomposite

    Science.gov (United States)

    Heydari, Hamid; Gholivand, Mohammad Bagher

    2017-03-01

    In this work, we have developed a novel nanocomposite via deposition of ceria (CeO2) on nitrogen-doped reduced graphene (CeO2/NRGO). NRGO was synthesized through a facile, safe, and scalable method to achieve simultaneous thermal reduction along with nitrogen doping of graphene oxide (GO) in air at much lower reaction temperature. CeO2/NRGO was prepared via a sonochemical method in which ceria nanoparticles were uniformly distributed on NRGO sheets. The structure and morphology of CeO2/NRGO nanocomposites were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR), and Raman spectroscopy. Electrochemical properties of the proposed nanocomposite electrodes were investigated by cyclic voltammetry (CV), galvanostatic charge/discharge, continuous cyclic voltammetry (CCV), and electrochemical impedance spectroscopy (EIS) measurements. CeO2-NRGO nanocomposite electrodes showed excellent supercapacitive behavior, including much higher specific capacitance (230 F g-1 at 2 mV s-1) and higher rate capability compared to pure N-graphene. The cycling stability of the electrodes was measured by continues cyclic voltammetry (CCV) technique. The CCV showed that the specific capacitance of the CeO2/NRGO and NRGO nanocomposite maintained at 94.1 and 93.2% after 4000 cycles. The results suggest its promising potential as efficient electrode material for supercapacitors.

  14. Catalytic wet air oxidation with Ni- and Fe-doped mixed oxides derived from hydrotalcites.

    Science.gov (United States)

    Ovejero, G; Rodríguez, A; Vallet, A; Gómez, P; García, J

    2011-01-01

    Catalytic wet air oxidation of Basic Yellow 11 (BY11), a basic dye, was studied in a batch reactor. Layered double hydroxides with the hydrotalcite-like structure containing nickel or iron cations have been prepared by coprecipitation and subsequently calcined leading to Ni- and Fe-doped mixed oxides, respectively. Compared with the results in the wet air oxidation of BY11, these catalysts showed high activity for total organic carbon (TOC), toxicity and dye removal at 120 degrees C and 50 bars after 120 min. It has been demonstrated that the activity depended strongly on the presence of catalyst. The results show that catalysts containing nickel provide a higher extent of oxidation of the dye whereas the reaction carried out with the iron catalyst is faster. The Ni and Fe dispersion determined from the TPR results was higher for the catalysts with a lower Ni or Fe content and decreased for higher Ni or Fe contents. On the basis of activity and selectivity, the Ni containing catalyst with the medium (3%) Ni content was found to be the best catalyst. Finally, a relationship between metal content of the catalyst and reaction rate has been established.

  15. Synthesis and characterization of cobalt oxide nanocomposite based on the Co3O4-zeolite Y

    Science.gov (United States)

    Davar, Fatemeh; Fereshteh, Zeinab; Shoja Razavi, Hadi; Razavi, Reza Shoja; Loghman-Estarki, Mohammad Reza

    2014-02-01

    The Co3O4 nanocomposite was synthesized by an ion-exchange of cobalt ions and Y zeolite in the presence of sodium hydroxide and calcination treatment. The products were characterized by X-ray diffraction (XRD), Raman analysis, scanning electron microscope (SEM), transmission electron microscope (TEM), BET, Energy-dispersive X-ray spectroscopy (EDX) and Fourier transform infrared (FTIR) spectroscopy. The sizes of the migrated Co3O4 particles out of Y zeolite super cage were in the range of 29 ± 5 nm. Finally, the magnetic property of as-obtained product was investigated in a vibrating sample magnetometer (VSM). This nanocomposite showed a paramagnetic behavior at room temperature.

  16. Green synthesis of AgI-reduced graphene oxide nanocomposites: Toward enhanced visible-light photocatalytic activity for organic dye removal

    Energy Technology Data Exchange (ETDEWEB)

    Reddy, D. Amaranatha; Lee, Seunghee; Choi, Jiha; Park, Seonhwa; Ma, Rory; Yang, Haesik; Kim, Tae Kyu, E-mail: tkkim@pusan.ac.kr

    2015-06-30

    Graphical abstract: - Highlights: • A novel green synthesis of AgI-RGO nanocomposites. • Significant improvement of the photocatalytic activity in RGO wrapped composites. • Additive promoted photocatalytic performance in AgI-RGO composites. • AgI-RGO nanocomposites may find applications in luminescent and catalytic devices. - Abstract: Novel reduced graphene oxide (RGO) enwrapped AgI nanocomposites were successfully fabricated by a facile template-free ultrasound-assisted method at room temperature. The structural, morphological, and optical studies demonstrate that the obtained nanostructures have good crystallinity and that the graphene nanosheets are decorated densely with AgI nanostructures. The photocatalytic activity of the composite was evaluated by the degradation of an organic dye, Rhodamine B (RhB), under visible-light irradiation. The results indicate that AgI with incorporated graphene exhibited much higher photocatalytic activity than the pure AgI due to the improved separation efficiency of the photogenerated carriers and that it prolonged the lifetime of the electron–hole pairs due to the chemical bonding between AgI and graphene. AgI (0.4 mg mL{sup −1} of graphene oxide) nanocomposites displayed the highest photocatalytic degradation efficiency and the corresponding catalytic efficiencies within 70 min were ∼96%. Moreover, with the assistance of H{sub 2}O{sub 2} the photocatalytic ability of the as-obtained AgI-RGO nanocomposites was enhanced. The corresponding catalytic efficiencies within 30 min were ∼96.8% (for 1 mL H{sub 2}O{sub 2}) under the same irradiation conditions. The excellent visible-light photocatalytic efficiency and luminescence properties make the AgI-RGO nanocomposites promising candidates for the removal of organic dyes for water purification and enable their application in near-UV white LEDs.

  17. Efficient phosphate sequestration for water purification by unique sandwich-like MXene/magnetic iron oxide nanocomposites

    Science.gov (United States)

    Zhang, Qingrui; Teng, Jie; Zou, Guodong; Peng, Qiuming; Du, Qing; Jiao, Tifeng; Xiang, Jianyong

    2016-03-01

    Rationally tailored intercalation for two-dimensional (2D) layered MXene materials has aroused extraordinary enthusiasm for broadening their applications. Herein, a novel sandwiched structural 2D MXene-iron oxide (MXI) material, prepared by selectively exfoliating an Al layer followed by magnetic ferric oxide intercalation, exhibits remarkable applicability to trace phosphate sequestration in the environmental remediation realm. Compared with commercial adsorbents, the resultant MXI nanocomposite exhibits a fast separation in 120 s together with the superior treatment capacities of 2100 kg and 2400 kg per kg in simulated and real phosphate wastewater applications, respectively. Such efficient sequestration is ascribed to the formation of a unique nano-ferric oxide morphology. The ultrafine nano-Fe2O3 particles can intercalate into the interior layers of MXene, widening the layer distance, and stimulating the available overlapping activated layers; while the efficient phosphate removal can be achieved by the strong complexation onto the embedded magnetic nano-Fe3O4 with a unique sandwich-structure as well as the stimulated Ti-O terminal within MXene. Apart from the fact that this approach suggests a complementary means for environmental remediation, it opens a new trajectory to achieve the functionalization of MXene.Rationally tailored intercalation for two-dimensional (2D) layered MXene materials has aroused extraordinary enthusiasm for broadening their applications. Herein, a novel sandwiched structural 2D MXene-iron oxide (MXI) material, prepared by selectively exfoliating an Al layer followed by magnetic ferric oxide intercalation, exhibits remarkable applicability to trace phosphate sequestration in the environmental remediation realm. Compared with commercial adsorbents, the resultant MXI nanocomposite exhibits a fast separation in 120 s together with the superior treatment capacities of 2100 kg and 2400 kg per kg in simulated and real phosphate wastewater

  18. Polyol mediated nano size zinc oxide and nanocomposites with poly(methyl methacrylate

    Directory of Open Access Journals (Sweden)

    2011-07-01

    Full Text Available Organophilic nano ZnO particles have been synthesized in various diols (ethylene glycol – EG, 1,2 propane diol – PD, 1,4 butane diol – BD and tetra(ethylene glycol – TEG in the presence of p-toluenesulfonic acid, p-TsOH, as an end capping agent. The addition of p-TsOH reduces the ZnO particle size and increases its crystallite size. With increasing diol main chain length the ZnO particle size increases (EG (32 nm < PD (33 nm < BD (72 nm < TEG (86 nm. Using the assynthesized and unmodified ZnO nanocomposites with poly(methyl methacrylate, PMMA, matrix have been prepared by the in-situ bulk polymerization of methyl methacrylate, MMA. The addition of surface modifiers is avoided which is an advantage for the application since they can influence other properties of the material. ZnO particles, especially those with smaller particle sizes (EG – 32 nm, PD – 33 nm showed enhanced effect on the thermal stability of PMMA, ultraviolet, UV, absorption and transparency for visible light. Transparent materials with high UV absorption and with enhanced resistance to sunlight were obtained by optimizing the nanocomposite preparation procedure using ZnO particles of about 30 nm size in concentrations between 0.05 and 0.1 wt%. The reported nanocomposite preparation procedure is compatible with the industrial process of PMMA sheet production.

  19. Multiwalled carbon nanotubes-zinc oxide nanocomposites as low temperature toluene gas sensor

    Science.gov (United States)

    Septiani, Ni Luh Wulan; Yuliarto, Brian; Nugraha; Dipojono, Hermawan Kresno

    2017-03-01

    The performance of nanocomposite MWCNT-ZnO thin films was investigated as toluene gas sensor. The nanocomposites MWCNT-ZnO thin films were synthesized by reflux method with the variation of MWCNT:ZnO ratio on 1:0, 3:1, 1:1, 1:3, and 0:1. Crystallinity and morphology characterization show that the crystal structure was not influenced by the presence of MWCNT, and the presence of MWCNTs could prevent the agglomeration of ZnO nanostructure. The dynamic response curve of nanocomposites MWCNT-ZnO thin films shows two different patterns at low temperature region and high temperature region. At low temperature region, the sensor response decreases as the increasing operating temperature and increasing the concentration of ZnO. On the other hand, at high temperature region, the sensor response increases as the increasing operating temperature and increasing the concentration of ZnO. Moreover, the variation concentration of MWCNT and ZnO can decrease the operating temperature of the sensors. The sensor with the ratio of MWCNT:ZnO at 1:3 show highest sensor response that reaches 17% at 150 °C of operating temperature, while the pure MWCNTs and pure ZnO show no response at that temperature.

  20. Polyol-Mediated Synthesis of Zinc Oxide Nanorods and Nanocomposites with Poly(methyl methacrylate

    Directory of Open Access Journals (Sweden)

    Alojz Anžlovar

    2012-01-01

    Full Text Available ZnO nanorods (length 30–150 nm were synthesized in di(ethylene glycol using Zn(CH3COO2 as a precursor and para-toluene sulphonic acid, p-TSA, as an end-capping agent. Increasing the concentration of p-TSA above 0.1 M causes the reduction of the ZnO length. Nanocomposites with poly(methyl methacrylate were prepared using unmodified nanorods. They enhanced the UV absorption of nanocomposites (∼98% at low ZnO concentrations (0.05–0.1 wt.%, while visible light transparency was high. At concentrations of 1 wt.% and above, nanorods enhanced the thermal stability of nanocomposites. At low concentrations (0.05–0.1 wt.%, they increased the storage modulus of material and shifted Tg towards higher temperatures as shown by dynamic mechanical analysis, DMA, while at higher concentrations (1.0 wt.% this effect was deteriorated. DMA also showed that spherical ZnO particles have a more pronounced effect on the storage modulus and Tg than nanorods.

  1. Oxidative stabilization of mixed mayonnaises made with linseed oil and saturated medium-chain triglyceride oil

    DEFF Research Database (Denmark)

    Raudsepp, Piret; Brüggemann, Dagmar A.; Lenferink, Aufried;

    2014-01-01

    Mayonnaises, made with either saturated medium chain triglyceride (MCT) oil or unsaturated purified linseed oil (LSO), were mixed. Raman confocal microspectrometry demonstrated that lipid droplets in mixed mayonnaise remained intact containing either MCT oil or LSO. Peroxide formation during stor...... simply diluting unsaturated triglycerides with saturated triglycerides is causing the oxidative stabilization observed for mixed mayonnaise and mixed oil mayonnaise. © 2013 Elsevier Ltd. All rights reserved.......Mayonnaises, made with either saturated medium chain triglyceride (MCT) oil or unsaturated purified linseed oil (LSO), were mixed. Raman confocal microspectrometry demonstrated that lipid droplets in mixed mayonnaise remained intact containing either MCT oil or LSO. Peroxide formation during...... storage was lower in mixed mayonnaise compared to LSO mayonnaise, while in mixed oil mayonnaise the level of peroxides was constantly low. Mixed oil mayonnaise had a lower rate of oxygen consumption than mixed mayonnaise, LSO mayonnaise having the highest rate. The decay of water-soluble nitroxyl radicals...

  2. Graphene oxide-enhanced sol-gel transition sensitivity and drug release performance of an amphiphilic copolymer-based nanocomposite.

    Science.gov (United States)

    Hu, Huawen; Wang, Xiaowen; Lee, Ka I; Ma, Kaikai; Hu, Hong; Xin, John H

    2016-08-19

    We report the fabrication of a highly sensitive amphiphilic copolymer-based nanocomposite incorporating with graphene oxide (GO), which exhibited a low-intensity UV light-triggered sol-gel transition. Non-cytotoxicity was observed for the composite gels after the GO incorporation. Of particular interest were the microchannels that were formed spontaneously within the GO-incorporated UV-gel, which expedited sustained drug release. Therefore, the present highly UV-sensitive, non-cytotoxic amphiphilic copolymer-based composites is expected to provide enhanced photothermal therapy and chemotherapy by means of GO's unique photothermal properties, as well as through efficient passive targeting resulting from the sol-gel transition characteristic of the copolymer-based system with improved sensitivity, which thus promises the enhanced treatment of patients with cancer and other diseases.

  3. Preparation of MoS₂-polyvinylpyrrolidone nanocomposites for flexible nonvolatile rewritable memory devices with reduced graphene oxide electrodes.

    Science.gov (United States)

    Liu, Juqing; Zeng, Zhiyuan; Cao, Xiehong; Lu, Gang; Wang, Lian-Hui; Fan, Qu-Li; Huang, Wei; Zhang, Hua

    2012-11-19

    A facile method for exfoliation and dispersion of molybdenum disulfide (MoS2) with the aid of polyvinylpyrrolidone (PVP) is proposed. The resultant PVP-coated MoS2 nanosheets, i.e., MoS2-PVP nanocomposites, are well dispersed in the low-boiling ethanol solvent, facilitating their thin film preparation and the device fabrication by solution processing technique. As a proof of concept, a flexible memory diode with the configuration of reduced graphene oxide (rGO)/MoS2-PVP/Al exhibited a typical bistable electrical switching and nonvolatile rewritable memory effect with the function of flash. These experimental results prove that the electrical transition is due to the charge trapping and detrapping behavior of MoS2 in the PVP dielectric material. This study paves a way of employing two-dimensional nanomaterials as both functional materials and conducting electrodes for the future flexible data storage.

  4. Graphene oxide-enhanced sol-gel transition sensitivity and drug release performance of an amphiphilic copolymer-based nanocomposite

    Science.gov (United States)

    Hu, Huawen; Wang, Xiaowen; Lee, Ka I.; Ma, Kaikai; Hu, Hong; Xin, John H.

    2016-08-01

    We report the fabrication of a highly sensitive amphiphilic copolymer-based nanocomposite incorporating with graphene oxide (GO), which exhibited a low-intensity UV light-triggered sol-gel transition. Non-cytotoxicity was observed for the composite gels after the GO incorporation. Of particular interest were the microchannels that were formed spontaneously within the GO-incorporated UV-gel, which expedited sustained drug release. Therefore, the present highly UV-sensitive, non-cytotoxic amphiphilic copolymer-based composites is expected to provide enhanced photothermal therapy and chemotherapy by means of GO’s unique photothermal properties, as well as through efficient passive targeting resulting from the sol-gel transition characteristic of the copolymer-based system with improved sensitivity, which thus promises the enhanced treatment of patients with cancer and other diseases.

  5. Nanocomposite Films of V2O5-MoO3 Xerogel with Poly Ethylene Oxide Intercalation

    Institute of Scientific and Technical Information of China (English)

    ZHENG Jin-xia; CHEN Wen; JIANG Cong-sheng; XU Qing; KE Man-zhu

    2003-01-01

    Poly ethylene oxide(PEO)x-V2O5-MoO3(x=0,0.5,1) films were prepared by the sol-gel method.The synthesis and structure of the films were investigated by XRD,TG-DTA,FTIR,etc.The results show that V2O5-MoO3 xerogel has a layered structure and its interlayer space increased from 1.3181nm at x=0 to 1.7898nm at x=1 after the nanocomposite films were dried,and PEO in the interlayer changes the interface structure by forming hydrogen bonds with V=O bands.CV measurement indicates that the intercalation of PEO improves insertion/extration properties of Li+ ions in the interlayer.

  6. Construction of spongy antimony-doped tin oxide/graphene nanocomposites using commercially available products and its excellent electrochemical performance

    Science.gov (United States)

    Zhao, Xiaowei; Zhang, Jingwei; Zhang, Jiwei; Gong, Chunhong; Gu, Xiufang; Ma, Zhihua; Zhou, Jingfang; Yu, Laigui; Zhang, Zhijun

    2015-10-01

    We construct successfully a porous antimony-doped tin oxide (ATO)/nitrogen-doped graphene 3-dimensional (3D) frameworks (denoted as ATO/NG/TEPA; TEPA refers to tetraethylenepentamine) by a one-pot hydrothermal process, with which TEPA aqueous solution is adopted to easily re-disperse commercial ATO precursor forming a transparent hydrosol. The results show that TEPA plays a key role in the construction of ATO/NG/TEPA, not only acting as a peptization reagent to re-disperse ATO precursor nanoparticles, and as a linker to combine ATO with graphene sheets. The as-fabricated ATO/NG/TEPA hybrid as the negative electrode of lithium ion batteries exhibits excellent lithium storage capacity and cycling stability. With the advantage of easily re-dispersing commercial ATO, the present synthetic route may be put into use for the large-scale production of the titled nanocomposites as the anode material of lithium ion batteries.

  7. Reduced Graphene Oxide-Cu0.5Ni0.5Fe2O4-Polyaniline Nanocomposite: Preparation, Characterization and Microwave Absorption Properties

    Science.gov (United States)

    Dat, Tran Quang; Ha, Nguyen Tran; Hung, Do Quoc

    2017-02-01

    Reduced graphene oxide-Cu0.5Ni0.5Fe2O4-polyaniline nanocomposite (RGO-CNF-PANI) was synthesized by a three-step method. The morphology, structure and magnetic properties of composite samples were characterized by scanning electron microscopy, x-ray diffraction, Fourier transform infrared spectroscopy, Raman spectroscopy (RAMAN) and vibrating sample magnetometer. It was found that reduced graphene oxide was exfoliated and decorated homogeneously with ferrite nanoparticles having diameters between 11 nm and 21 nm. The polyaniline was coated by an in situ chemical oxidation polymerization. The measurement of magnetic properties found the remanence (Mr) and coercive field (Hc) were near zero, indicating that the obtained material was superparamagnetic. The microwave measurements found that the nanocomposite exhibited a good absorption property with the optimum matching thickness of 3 mm in the frequency of 8-12 GHz. The value of the maximum RL was -40.7 dB at 9.8 GHz.

  8. Highly Sensitive Electrochemical Biosensor for Evaluation of Oxidative Stress Based on the Nanointerface of Graphene Nanocomposites Blended with Gold, Fe3O4, and Platinum Nanoparticles.

    Science.gov (United States)

    Wang, Le; Zhang, Yuanyuan; Cheng, Chuansheng; Liu, Xiaoli; Jiang, Hui; Wang, Xuemei

    2015-08-26

    High levels of H2O2 pertain to high oxidative stress and are associated with cancer, autoimmune, and neurodegenerative disease, and other related diseases. In this study, a sensitive H2O2 biosensor for evaluation of oxidative stress was fabricated on the basis of the reduced graphene oxide (RGO) nanocomposites decorated with Au, Fe3O4, and Pt nanoparticles (RGO/AuFe3O4/Pt) modified glassy carbon electrode (GCE) and used to detect the released H2O2 from cancer cells and assess the oxidative stress elicited from H2O2 in living cells. Electrochemical behavior of RGO/AuFe3O4/Pt nanocomposites exhibits excellent catalytic activity toward the relevant reduction with high selection and sensitivity, low overpotential of 0 V, low detection limit of ∼0.1 μM, large linear range from 0.5 μM to 11.5 mM, and outstanding reproducibility. The as-prepared biosensor was applied in the measurement of efflux of H2O2 from living cells including healthy normal cells and tumor cells under the external stimulation. The results display that this new nanocomposites-based biosensor is a promising candidate of nonenzymatic H2O2 sensor which has the possibility of application in clinical diagnostics to assess oxidative stress of different kinds of living cells.

  9. An ultrasensitive electrochemical DNA biosensor based on a copper oxide nanowires/single-walled carbon nanotubes nanocomposite

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Mei [Key Laboratory of Biorheology Science and Technology, Ministry of Education, College of Bioengineering, Chongqing University, Chongqing 400044 (China); Hou, Changjun, E-mail: houcj@cqu.edu.cn [Key Laboratory of Biorheology Science and Technology, Ministry of Education, College of Bioengineering, Chongqing University, Chongqing 400044 (China); National Key Laboratory of Fundamental Science of Micro/Nano-Device and System Technology, Chongqing University, Chongqing 400044 (China); Huo, Danqun [Key Laboratory of Biorheology Science and Technology, Ministry of Education, College of Bioengineering, Chongqing University, Chongqing 400044 (China); National Key Laboratory of Fundamental Science of Micro/Nano-Device and System Technology, Chongqing University, Chongqing 400044 (China); Yang, Mei [Key Laboratory of Biorheology Science and Technology, Ministry of Education, College of Bioengineering, Chongqing University, Chongqing 400044 (China); Fa, Huanbao [College of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400044 (China)

    2016-02-28

    Graphical abstract: A novel and sensitive electrochemical biosensor based on hybrid nanocomposite consisting of copper oxide nanowires (CuO NWs) and carboxyl-functionalized single-walled carbon nanotubes (SWCNTs-COOH) was first developed for the detection of the specific-sequence target DNA. This schematic represents the fabrication procedure of our DNA biosensor. - Highlights: • An ultrasensitive DNA electrochemical biosensor was developed. • CuO NWs entangled with the SWCNTs formed a mesh structure with good conductivity. • It is the first time use of CuONWs-SWCNTs hybrid nanocomposite for DNA detection. • The biosensor is simple, selective, stable, and sensitive. • The biosensor has great potential for use in analysis of real samples. - Abstract: Here, we developed a novel and sensitive electrochemical biosensor to detect specific-sequence target DNA. The biosensor was based on a hybrid nanocomposite consisting of copper oxide nanowires (CuO NWs) and carboxyl-functionalized single-walled carbon nanotubes (SWCNTs-COOH). The resulting CuO NWs/SWCNTs layers exhibited a good differential pulse voltammetry (DPV) current response for the target DNA sequences, which we attributed to the properties of CuO NWs and SWCNTs. CuO NWs and SWCNTs hybrid composites with highly conductive and biocompatible nanostructure were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), and cyclic voltammetry (CV). Immobilization of the probe DNA on the electrode surface was largely improved due to the unique synergetic effect of CuO NWs and SWCNTs. DPV was applied to monitor the DNA hybridization event, using adriamycin as an electrochemical indicator. Under optimal conditions, the peak currents of adriamycin were linear with the logarithm of target DNA concentrations (ranging from 1.0 × 10{sup −14} to 1.0 × 10{sup −8} M), with a detection limit of 3.5 × 10{sup −15} M (signal/noise ratio of 3). The biosensor also showed high

  10. Effect of Sr on the properties of Ce–Zr–La mixed oxides

    Directory of Open Access Journals (Sweden)

    RICHUAN RAO

    2006-03-01

    Full Text Available Ce–Zr–La–Sr mixed oxides, with different Sr contents, were prepared by the sol–gel method. In a flow-system microreactor, the reduction properties and the oxygen storage capacity (OSC of the Ce–Zr–La–Sr mixed oxides were investigated by a temperature programmed reduction (TPR and a pulse technique. It was shown that the properties of the Ce–Zr–La mixed oxides depend on the Sr content and that the optimum Sr content in the Ce–Zr–La–Sr mixed oxide is 3 mol%. The Ce–Zr–La–Sr mixed oxides doped with 3 mol% Sr (Ce0.52Zr0.4La0.05Sr0.03O1.945 has the largest specific surface area and better reduction properties and oxygen storage capacity in comparison to the other investigated samples. The XRD results of the Ce–Zr–La–Sr mixed oxides showed that their X-ray diffraction patterns are well in agreement with that of fluorite-type CeO2 with Sr ions incorporated into the Ce–Zr–La mixed oxide structures. With increasing calcination temperature, the intensity of the X-ray diffraction peaks increased, but no new peaks were observed. All of these indicate that the synthesized samples had good thermal stability.

  11. Ternary hybrid polymeric nanocomposites through grafting of polystyrene on graphene oxide-TiO{sub 2} by surface initiated atom transfer radical polymerization (SI-ATRP)

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Arvind; Bansal, Ankushi; Behera, Babita; Jain, Suman L.; Ray, Siddharth S., E-mail: ssray@iip.res.in

    2016-04-01

    A ternary hybrid of graphene oxide-titania-polystyrene (GO-TiO{sub 2}-PS) nanocomposite is developed where polystyrene composition is regulated by controlling growth of polymer chains and nanoarchitectonics is discussed. Graphene Oxide-TiO{sub 2} (GO-TiO{sub 2}) nanocomposite is prepared by in-situ hydrothermal method and the surface is anchored with α-bromoisobutyryl bromide to activate GO-TiO{sub 2} as initiator for polymerization. In-situ grafting of polystyrene through surface initiated atom transfer radical polymerization (SI- ATRP) on this Br-functionalized nano-composite initiator yields GO-TiO{sub 2}-PS ternary hybrid. Varying the monomer amount and keeping the concentration of initiator constant, polystyrene chain growth is regulated with narrow poly-dispersivity to achieve desired composition. This composite is well characterized by various analytical techniques like FTIR, XRD, DSC, SEM, TEM, and TGA. - Highlights: • Nanocomposite of ternary hybrid of GO-TiO{sub 2} with polystyrene. • PS is surface grafted on GO-TiO{sub 2}. • Polymer chain lengths are well regulated by SI-ATRP living polymerization. • Thermal stability of this hybrid is relatively high.

  12. Polypropylene/Polyaniline Nanofiber/Reduced Graphene Oxide Nanocomposite with Enhanced Electrical, Dielectric, and Ferroelectric Properties for a High Energy Density Capacitor.

    Science.gov (United States)

    Cho, Sunghun; Kim, Minkyu; Lee, Jun Seop; Jang, Jyongsik

    2015-10-14

    This work demonstrates a ternary nanocomposite system, composed of polypropylene (PP), redoped PANI (r-PANI) nanofibers, and reduced graphene oxides (RGOs), for use in a high energy density capacitor. r-PANI nanofibers were fabricated by the combination methods of chemical oxidation polymerization and secondary doping processes, resulting in higher conductivity (σ≈156 S cm(-1)) than that of the primarily doped PANI nanofibers (σ≈16 S cm(-1)). RGO sheets with high electron mobility and thermal stability can enhance the conductivity of r-PANI/RGO (σ≈220 S cm(-1)) and thermal stability of PP matrix. These findings could be extended to combine the advantages of r-PANI nanofibers and RGO sheets for developing an efficient means of preparing PP/r-PANI/RGO nanocomposite. When the r-PANI/RGO cofillers (10 vol %) were added to PP matrix, the resulting PP/r-PANI/RGO nanocomposite exhibited high dielectric constant (ε'≈51.8) with small dielectric loss (ε″≈9.3×10(-3)). Furthermore, the PP/r-PANI/RGO nanocomposite was used for an energy-harvesting device, which demonstrated high energy density (Ue≈12.6 J cm(-3)) and breakdown strength (E≈5.86×10(3) kV cm(-1)).

  13. Facile and novel electrochemical preparation of a graphene-transition metal oxide nanocomposite for ultrasensitive electrochemical sensing of acetaminophen and phenacetin.

    Science.gov (United States)

    Jiang, Lin; Gu, Shuqing; Ding, Yaping; Jiang, Feng; Zhang, Zhen

    2014-01-07

    A facile and novel preparation strategy based on electrochemical techniques for the fabrication of electrodeposited graphene (EGR) and zinc oxide (ZnO) nanocomposite was developed. The morphology and structure of the EGR-based nanocomposite were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (XPS) and Raman spectroscopy. Meanwhile, the electrochemical performance of the nanocomposite was demonstrated with cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Due to the synergistic effect of EGR and ZnO nanoparticles, an ultrasensitive electrochemical sensor for acetaminophen (AC) and phenacetin (PCT) was successfully fabricated. The linearity ranged from 0.02 to 10 μM for AC and 0.06 to 10 μM for PCT with high sensitivities of 54,295.82 μA mM(-1) cm(2) for AC and 21,344.66 μA mM(-1) cm(2) for PCT, respectively. Moreover, the practical applicability was validated to be reliable and desirable in pharmaceutical detections. The excellent results showed the promise of the proposed preparation strategy of EGR-transition metal oxide nanocomposite in the field of electroanalytical chemistry.

  14. Improved performance of CdS/CdSe quantum dots sensitized solar cell by incorporation of ZnO nanoparticles/reduced graphene oxide nanocomposite as photoelectrode

    Science.gov (United States)

    Ghoreishi, F. S.; Ahmadi, V.; Samadpour, M.

    2014-12-01

    Here we present novel quantum dot sensitized solar cells (QDSSC) based on ZnO nanoparticles (NPs)/reduced graphene oxide (RGO) nanocomposite photoanodes for better light harvesting and energy conversion. Photoelectrodes are prepared by doctor blading ZnO NPs/GO nanocomposite paste on a fluorine doped tin oxide substrate which are then sintered at 450 °C to obtain ZnO NPs/RGO nanocomposites. The partial reduction of GO after thermal reduction, is studied by Fourier transform infrared and Raman spectroscopies. Cadmium sulfide (CdS) and cadmium selenide (CdSe) quantum dots are deposited on the films through successive ionic layer adsorption and reaction and chemical bath deposition methods, respectively. The unique properties of ZnO NPs/RGO photoanodes, lead to a significant enhancement in the photovoltaic properties of solar cells in comparison with bare ZnO photoanodes. Current-voltage characteristics of cells are studied and the best results are obtained from ZnO NPs-RGO/CdS/CdSe with photoelectric conversion efficiency of 2.20% which is almost two times higher than cells which are made by pure ZnO NPs as photoanode (1.28%). Electrochemical impedance measurements show that the enhancement can be attributed to the increase of electron transfer rate in the ZnO NPs/RGO nanocomposite photoanode which arises from the ultrahigh electron mobility in graphene (RGO) sheets.

  15. SiO2-coated magnetic graphene oxide modified with polypyrrole-polythiophene: A novel and efficient nanocomposite for solid phase extraction of trace amounts of heavy metals.

    Science.gov (United States)

    Molaei, Karam; Bagheri, Hasan; Asgharinezhad, Ali Akbar; Ebrahimzadeh, Homeira; Shamsipur, Mojtaba

    2017-05-15

    The synthesis of a novel nanocomposite comprised of SiO2-coated magnetic graphene oxide modified with a pyrrole-thiophene (mGO/SiO2@coPPy-Th) copolymer is reported in the present work. The nanocomposite was applied for the fast magnetic solid phase extraction (MSPE) of trace levels of copper, lead, chromium, zinc and cadmium from water and agricultural samples. The nanocomposite was prepared in three steps: (1) decoration of graphene oxide sheets with magnetite nanoparticles thorough a facile one-step chemical reaction strategy; (2) chemical grafting by a silica layer to obtain high stability in acidic solutions; and (3) surface modification by coPPy-Th via simultaneous oxidation polymerization of pyrrole and thiophene in the presence of mGO/SiO2 composite. The nanocomposite was subsequently characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD) and vibrating sample magnetometry (VSM) techniques. Several important experimental variables that could affect MSPE performance, including the pH of the sample, sorption time, sorbent dosage, eluent type and its concentration, eluent volume and elution time, were investigated and optimized. Under optimal conditions, the limits of detection for the target heavy metals ranged from 0.15 to 0.65μgL(-1). The maximum sorption capacity of the mGO/SiO2@coPPy-Th nanocomposite was 201, 230, 125, 98 and 80mgg(-1) for Cu(II), Pb(II), Zn(II), Cr(III) and Cd(II), respectively. Finally, the feasibility of the proposed method was investigated for the extraction and determination of the target metals from real matrices.

  16. Efficient room temperature oxidation of cyclohexane over highly active hetero-mixed WO3/V2O5 oxide catalyst

    CSIR Research Space (South Africa)

    Makgwane, PR

    2014-09-01

    Full Text Available An efficient room temperature catalyzed oxidation of cyclohexane to cyclohexanone (K) and cyclohexanol (A) was achieved over hetero-mixed tungsten–vanadia (WO(sub3)/V(sub2)O(sub5)) using H(sub2)O(sub2) oxidant. WO(sub3)/V(sub2)O(sub5) exhibited high...

  17. Catalytic performance for methane combustion of supported Mn-Ce mixed oxides

    Institute of Scientific and Technical Information of China (English)

    SHI Limin; CHU Wei; QU Fenfen; HU Jinyan; LI Minmin

    2008-01-01

    A series of supported Mn-Ce mixed oxide catalysts were prepared by the impregnation method and used for the oxidation of methane. The catalysts were characterized by N2 adsorption (BET), X-ray diffraction (XRD), laser Raman spectrum (LRS), and temperature programmed reduction (TPR) techniques. The XRD and LRS results confirmed the high dispersion of active components or formation of solid solution between manganese and cerium oxides in the bulk and on the surface of mixed oxide catalysts. The reducibility was remarka-bly promoted by the stronger synergistic interaction between the two oxides from H2-TPR measurements. As expected, all the experimental mixed oxide catalysts showed excellent activity for methane combustion at low temperature. Especially, for the catalyst with Mn-Ce ratio 3:7, methane conversion reached 92% at a temperature as low as 470 ℃.

  18. Electrochemically driven biocatalysis of the oxygenase domain of neuronal nitric oxide synthase in indium tin oxide nanoparticles/polyvinyl alcohol nanocomposite.

    Science.gov (United States)

    Xu, Xuan; Wollenberger, Ulla; Qian, Jing; Lettau, Katrin; Jung, Christiane; Liu, Songqin

    2013-12-01

    Nitric oxide synthase (NOS) plays a critical role in a number of key physiological and pathological processes. Investigation of electron-transfer reactions in NOS would contribute to a better understanding of the nitric oxide (NO) synthesis mechanism. Herein, we describe an electrochemically driven catalytic strategy, using a nanocomposite that consisted of the oxygenase domain of neuronal NOS (D290nNOSoxy), indium tin oxide (ITO) nanoparticles and polyvinyl alcohol (PVA). Fast direct electron transfer between electrodes and D290nNOSoxy was observed with the heterogeneous electron transfer rate constant (ket) of 154.8 ± 0.1s(-1) at the scan rate of 5 Vs(-1). Moreover, the substrate N(ω)-hydroxy-L-arginine (NHA) was used to prove the concept of electrochemically driven biocatalysis of D290nNOSoxy. In the presence of the oxygen cosubstrate and tetrahydrobiopterin (BH4) cofactor, the addition of NHA caused the decreases of both oxidation current at +0.1 V and reduction current at potentials ranging from -0.149 V to -0.549 V vs Ag/AgCl. Thereafter, a series of control experiments such as in the absence of BH4 or D290nNOSoxy were performed. All the results demonstrated that D290nNOSoxy biocatalysis was successfully driven by electrodes in the presence of BH4 and oxygen. This novel bioelectronic system showed potential for further investigation of NOS and biosensor applications.

  19. Facile synthesis of sandwiched Zn2GeO4-graphene oxide nanocomposite as a stable and high-capacity anode for lithium-ion batteries.

    Science.gov (United States)

    Zou, Feng; Hu, Xianluo; Qie, Long; Jiang, Yan; Xiong, Xiaoqin; Qiao, Yun; Huang, Yunhui

    2014-01-21

    Traditional metal anode materials in lithium-ion batteries are plagued by instability upon discharge-charge cycling. We report that a unique sandwiched Zn2GeO4-graphene oxide nanocomposite has been synthesized on a large scale through a simple ion-exchange reaction, whereby Zn2GeO4 nanorods with lengths of 600 nm and widths of 40 nm are homogeneously sandwiched into the graphene oxide matrix. Compared with bare Zn2GeO4 nanorods, a dramatic improvement in the electrochemical performance of the resulting nanocomposite has been achieved. In the voltage window of 0.001-3 V, the electrode of the Zn2GeO4-graphene oxide nanocomposite delivers a specific capacity as high as 1150 mA h g(-1) at 200 mA g(-1) after 100 discharge-charge cycles. Even at a high current density of 3.2 A g(-1), a capacity of 522 mA h g(-1) can be retained. The unusual electrochemical performance including highly reversible capacity and excellent rate capability arise from synergetic chemical coupling effects between Zn2GeO4 and graphene oxide.

  20. Ce-Fe-O mixed oxide as oxygen carrier for the direct partial oxidation of methane to syngas

    Institute of Scientific and Technical Information of China (English)

    魏永刚; 王华; 李孔斋

    2010-01-01

    The Ce-Fe-O mixed oxide with a ratio of Ce/Fe=7:3, which was prepared by coprecipitation method and employed as oxygen carrier, for direct partial oxidation of methane to syngas in the absence of gaseous oxygen was explored. The mixed oxide was characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM), and the catalytic performances were studied in a fixed-bed quartz reactor and a thermogravimetric reactor, respectively. Approximately 99.4% H2 se...

  1. The Two-Dimensional Nanocomposite of Molybdenum Disulfide and Nitrogen-Doped Graphene Oxide for Efficient Counter Electrode of Dye-Sensitized Solar Cells

    Science.gov (United States)

    Cheng, Chao-Kuang; Lin, Che-Hsien; Wu, Hsuan-Chung; Ma, Chen-Chi M.; Yeh, Tsung-Kuang; Chou, Huei-Yu; Tsai, Chuen-Horng; Hsieh, Chien-Kuo

    2016-02-01

    In this study, we reported the synthesis of the two-dimensional (2D) nanocomposite of molybdenum disulfide and nitrogen-doped graphene oxide (MoS2/nGO) as a platinum-free counter electrode (CE) for dye-sensitized solar cells (DSSCs). X-ray photoelectron spectroscopy (XPS), high-resolution transmission electron microscopy (HRTEM), and Raman spectroscopy were used to examine the characteristics of the 2D nanocomposite of MoS2/nGO. The cyclic voltammetry (CV), electrochemical impedance spectra (EIS), and the Tafel polarization measurements were carried out to examine the electrocatalytic abilities. XPS and Raman results showed the 2D behaviors of the prepared nanomaterials. HRTEM micrographs showed the direct evidence of the 2D nanocomposite of MoS2/nGO. The results of electrocatalytic examinations indicated the MoS2/nGO owning the low charge transfer resistance, high electrocatalytic activity, and fast reaction kinetics for the reduction of triiodide to iodide on the electrolyte-electrode interface. The 2D nanocomposite of MoS2/nGO combined the advantages of the high specific surface of nGO and the plenty edge sites of MoS2 and showed the promoted properties different from those of their individual constituents to create a new outstanding property. The DSSC with MoS2/nGO nanocomposite CE showed a photovoltaic conversion efficiency (PCE) of 5.95 % under an illumination of AM 1.5 (100 mW/cm2), which was up to 92.2 % of the DSSC with the conventional platinum (Pt) CE (PCE = 6.43 %). These results reveal the potential of the MoS2/nGO nanocomposite in the use of low-cost, scalable, and efficient Pt-free CEs for DSSCs.

  2. Preparation, Characterization and Dielectric Properties of Epoxy and Polyethylene Nanocomposites

    Science.gov (United States)

    Zhang, Chao; Mason, Ralf; Stevens, Gary

    Two very different kinds of polymer nanocomposites have been prepared, characterized and investigated by dielectric spectroscopy to investigate the effects of polymer-nanofiller matrix difference on the dielectric response of nanodielectric composites. Linear low density polyethylene (LLDPE) is a non-polar thermoplastic which has a high viscosity even in the melt phase and bisphenol-A epoxy resin with an anhydride hardener is a polar low viscosity thermosetting resin. Nanometric sized aluminium oxide filler was chosen as the common inorganic phase for both nanodielectrics. Generally, nanoparticles aggregate easily and are difficult to separate due to strong surface interactions. In this study various mixing methods were employed from ultrasonic liquid processing to controlled shear flow mixing to investigate the dispersion of the nanofillers. The resultant epoxy and polyethylene nanocomposites were characterized with SEM, TEM, and DSC. The dielectric properties and frequency response of the nanocomposites were measured in the frequency domain from 10-2 Hz to 106 Hz at different temperatures. In polyethylene nanocomposites, significant interfacial polarization is clearly seen. However, in epoxy nanocomposites, no obvious interfacial polarization is found. The results are discussed in terms of the difference in the electrical characteristics of the interfacial region between the polymers and the nano-alumina.

  3. Leaching of pyrite by acidophilic heterotrophic iron-oxidizing bacteria in pure and mixed cultures

    Energy Technology Data Exchange (ETDEWEB)

    Bacelar-Nicolau, P.; Johnson, D.B. [Univ. of Wales, Bangor (United Kingdom). School of Biological Sciences

    1999-02-01

    Seven strains of heterotrophic iron-oxidizing acidophilic bacteria were examined to determine their abilities to promote oxidative dissolution of pyrite (FeS{sub 2}) when they were grown in pure cultures and in mixed cultures with sulfur-oxidizing Thiobacillus spp. Only one of the isolates (strain T-24) oxidized pyrite when it was grown in pyrite-basal salts medium. However, when pyrite-containing cultures were supplemented with 0.02% (wt/vol) yeast extract, most of the isolates oxidized pyrite, and one (strain T-24) promoted rates of mineral dissolution similar to the rates observed with the iron-oxidizing autotroph Thiobacillus ferroxidans. Pyrite oxidation by another isolate (strain T-21) occurred in cultures containing between 0.005 and 0.05% (wt/vol) yeast extract but was completely inhibited in cultures containing 0.5% yeast extract. Ferrous iron was also needed for mineral dissolution by the iron-oxidizing heterotrophs, indicating that these organisms oxidize pyrite via the indirect mechanism. Mixed cultures of three isolates (strains T-21, T-232, and T-24) and the sulfur-oxidizing autotroph Thiobacillus thiooxidans promoted pyrite dissolution; since neither strains T-21 and T-23 nor T. thiooxidans could oxidize this mineral in yeast extract-free media, this was a novel example of bacterial synergism. Mixed cultures of strains T-21 and T-23 and the sulfur-oxidizing mixotroph Thiobacillus acidophilus also oxidized pyrite but to a lesser extent than did mixed cultures containing T. thiooxidans. Pyrite leaching by strain T -23 grown in an organic compound-rich medium and incubated either shaken or unshaken was also assessed. The potential environmental significance of iron-oxidizing heterotrophs in accelerating pyrite oxidation is discussed.

  4. Nanoparticles of TiAlZr mixed oxides as supports of hydrodesulfurization catalysts: Synthesis and characterization

    Energy Technology Data Exchange (ETDEWEB)

    Kraleva, E., E-mail: ekraleva@gmail.com [Institute of Biodiversity and Ecosystems Research, Bulgarian Academy of Sciences, Sofia, Gagarin st.2 (Bulgaria); Spojakina, A. [Institute of Catalysis, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria); Saladino, M.L. [Dipartimento di Chimica ' S. Cannizzaro' , Universita di Palermo and INSTM-Udr Palermo, Parco d' Orleans II Viale delle Scienze pad 17, I-90128 Palermo,Italy (Italy); Caponetti, E. [Dipartimento di Chimica ' S. Cannizzaro' , Universita di Palermo and INSTM-Udr Palermo, Parco d' Orleans II Viale delle Scienze pad 17, I-90128 Palermo,Italy (Italy); Centro Grandi Apparecchiature - UniNetLab, Universita di Palermo, Via F. Marini 14, I-90128 Palermo (Italy); Nasillo, G. [Centro Grandi Apparecchiature - UniNetLab, Universita di Palermo, Via F. Marini 14, I-90128 Palermo (Italy); Jiratova, K. [Institute of Chemical Process Fundamentals, 16502 Prague 6 (Czech Republic)

    2012-02-05

    Highlights: Black-Right-Pointing-Pointer Preparation of ternary mixed oxide by sol-gel method. Black-Right-Pointing-Pointer Catalytic properties of the three-mixed oxides. Black-Right-Pointing-Pointer Heteropolyacid H{sub 3}PMo{sub 12}O{sub 40} and its cobalt salt Co{sub 1.5}PMo{sub 12}O{sub 40} that of active components in catalytic systems for thiophene hydrodesulfurization (HDS). - Abstract: TiAlZr mixed oxides, synthesized using sol-gel method, were characterized and used as supports of hydrodesulfurization catalysts (12 wt% Mo) prepared by impregnation either with molybdenum heteropolyacid H{sub 3}PMo{sub 12}O{sub 40} or its cobalt salt Co{sub 1.5}PMo{sub 12}O{sub 40}. Structure, morphology and textural properties of oxides and catalysts were characterized using X-ray powder diffraction (XRD), Raman spectroscopy, Nitrogen adsorption porosimetry, TEM-EDS, temperature-programmed desorption (TPD) and temperature-programmed reduction (TPR) techniques. Activity of the catalytic systems was tested in thiophene hydrodesulfurization (HDS). No formation of a new oxide phase was revealed in the synthesized mixed materials. However the effect of separated oxides on the structure of ternary oxides was observed. Maximum in HDS activity of Mo containing samples was determined by optimum content of alumina in the mixed oxides. Incorporation of cobalt into the heteropolyacid increased the HDS activity about two times and masked the effect of the support composition.

  5. Ethanol steam reforming over Mg-Al mixed-oxide catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Coleman, L.J.; Hudgins, R.R.; Silveston, P.L.; Croiset, E. [Waterloo Univ., ON (Canada). Dept. of Chemical Engineering

    2007-07-01

    Eight magnesium-aluminium (Mg-Al) mixed oxides and magnesium oxide (MgO) and aluminium oxide (Al{sub 2}O{sub 3}) were studied in order to identify the most effective Mg-Al mixed oxide for hydrogen production via ethanol steam reforming. Co-precipitated precursors were calcinated to prepare the Mg-Al mixed oxides. Activity and selectivity of the mixed oxides for ethanol steam reforming were evaluated at 773 and 923 K. Results showed that all catalysts performed poorly during the steam reforming reaction, and produced low rates of hydrogen, carbon monoxide (CO) and carbon dioxide (CO{sub 2}). Catalysts with an MgAl{sub 2}O{sub 4} spinel crystal structure gave the best performance at both reaction temperatures. However, carbon deposits were discovered on all catalysts for reactions performed at 923 K. Co-precipitation resulted in more effective contact between the Mg and Al in the form of Mg-Al LDO and MgAL{sub 2}O{sub 3}. The absence of pure oxides suggested that Mg and Al were chemically coupled in the mixed oxide catalysts. Results of the study showed that the catalyst with an atomic ratio of 0.66 Mg1Al2 was the most active and achieved the highest rates of production for hydrogen. 14 refs., 3 tabs., 1 fig.

  6. Polyurethane Nanocomposites Containing Reduced Graphene Oxide, FTIR, Raman, and XRD Studies

    OpenAIRE

    Michał Strankowski; Damian Włodarczyk; Łukasz Piszczyk; Justyna Strankowska

    2016-01-01

    Recently, graphene and other graphene-based materials have become an essential part of composite science and technology. Their unique properties are not only restricted to graphene but also shared with derivative compounds like graphene oxide, reduced graphene oxide, functionalized graphene, and so forth. One of the most structurally important materials, graphene oxide (GO), is prepared by the oxidation of graphite. Though removal of the oxide groups can create vacancies and structural defect...

  7. Study on Catalysts with Rhodium Loading on Different Cerium-Zirconium Mixed Oxides

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The catalysts with Rh loading on different cerium-zirconium mixed oxides were characterized by BET, H2-TPR and OSC. The effects of different cerium-zirconium mixed oxides on catalytic performance and thermal stability of Rh loaded catalyst were studied. The results show that: (1) Rh can enhance cerium-zirconium mixed oxides OSC and catalytic reaction rates; (2) cerium-zirconium mixed oxides with high Ce contents and low Zr contents are more favorable to the stability of catalysts. Moreover, the contents of CeO2 have important effect on catalysts characteristics, and the addition of some rare earth components, such as La, Pr and Nd also have some influences.

  8. Iron oxide nanocomposite magnets produced by partial reduction of strontium hexaferrite

    Directory of Open Access Journals (Sweden)

    Tikkanen Jussi

    2014-07-01

    Full Text Available Isotropic bulk nanocomposite permanent magnets were produced with strontium hexaferrite, SrO·6Fe2O3, and magnetite, Fe3O4, as the magnetically hard and soft components. A novels synthesis scheme based on the partial reduction of SrO·6Fe2O3 was employed. In two parallel experiments, nano- and microcrystalline SrO·6Fe2O3 particles were compacted into pellets along with a controlled, understoichiometric amount of potato starch as a reducing agent. The pellets were then sintered in a passive atmosphere. Based on XRD and room temperature magnetic hysteresis measurements, it was concluded that a fraction of the SrO·6Fe2O3 input material had been reduced into Fe3O4. In comparison with pure SrO·6Fe2O3 control pellets, these composites exhibited maximum energy product increases in excess of 5 % due to remanence boosting. The improvement of magnetic properties was attributed to an efficient exchange spring coupling between the magnetic phases. Interestingly, as the synthesis scheme also worked for microcrystalline SrO·6Fe2O3 , the method could presumably be adapted to yield crystallographically oriented bulk nanocomposite magnets.

  9. Preparation of highly stable fullerene C60 decorated graphene oxide nanocomposite and its sensitive electrochemical detection of dopamine in rat brain and pharmaceutical samples.

    Science.gov (United States)

    Thirumalraj, Balamurugan; Palanisamy, Selvakumar; Chen, Shen-Ming; Lou, Bih-Show

    2016-01-15

    The research community has continuously paid much attention on the preparation of hybrid of carbon nanomaterials owing to combine their unique properties. Herein, we report the preparation of highly stable fullerene C60 (C60) wrapped graphene oxide (GO) nanocomposite by using a simple sonication method. The fabricated GO-C60 nanocomposite modified glassy carbon electrode shows a good sensitivity and lower oxidation overpotential towards dopamine (DA) than that of pristine GO and C60. The fabricated sensor detects the DA in the linear response range of 0.02-73.5μM. The limit of detection is estimated to be 0.008μM based on 3σ with a sensitivity of 4.23μAμM(-1)cm(-2). The fabricated sensor also exhibits other features such as good selectivity, stability, reproducibility and repeatability. The proposed sensor exhibits good practicality towards the detection of DA in rat brain and commercial DA injection samples.

  10. Nanoporous bimetallic Pt-Au alloy nanocomposites with superior catalytic activity towards electro-oxidation of methanol and formic acid.

    Science.gov (United States)

    Zhang, Zhonghua; Wang, Yan; Wang, Xiaoguang

    2011-04-01

    We present a facile route to fabricate novel nanoporous bimetallic Pt-Au alloy nanocomposites by dealloying a rapidly solidified Al(75)Pt(15)Au(10) precursor under free corrosion conditions. The microstructure of the precursor and the as-dealloyed sample was characterized using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, high-resolution transmission electron microscopy, and energy dispersive X-ray (EDX) analysis. The Al(75)Pt(15)Au(10) precursor is composed of a single-phase Al(2)(Au,Pt) intermetallic compound, and can be fully dealloyed in a 20 wt.% NaOH or 5 wt.% HCl aqueous solution. The dealloying leads to the formation of the nanoporous Pt(60)Au(40) nanocomposites (np-Pt(60)Au(40) NCs) with an fcc structure. The morphology, size and crystal orientation of grains in the precursor can be conserved in the resultant nanoporous alloy. The np-Pt(60)Au(40) NCs consist of two zones with distinct ligament/channel sizes and compositions. The formation mechanism of these np-Pt(60)Au(40) NCs can be rationalized based upon surface diffusion of more noble elements and spinodal decomposition during dealloying. Electrochemical measurements demonstrate that the np-Pt(60)Au(40) NCs show superior catalytic activity towards the electro-oxidation of methanol and formic acid in the acid media compared to the commercial JM-Pt/C catalyst. This material can find potential applications in catalysis related areas, such as direct methanol or formic acid fuel cells. Our findings demonstrate that dealloying is an effective and simple strategy to realize the alloying of immiscible systems under mild conditions, and to fabricate novel nanostructures with superior performance.

  11. Blocked-micropores, surface functionalized, bio-compatible and silica-coated iron oxide nanocomposites as advanced MRI contrast agent

    Energy Technology Data Exchange (ETDEWEB)

    Darbandi, Masih, E-mail: masih.darbandi@uni-due.de [Vanderbilt University, Department of Physics and Vanderbilt Institute of Nanoscale Science and Engineering (VINSE) (United States); Laurent, Sophie [University of Mons, Department of General, Organic and Biomedical Chemistry NMR and Molecular Imaging Laboratory (Belgium); Busch, Martin [University of Duisburg-Essen, Nanoparticle Process Technology, Faculty of Engineering and Center for Nanointegration Duisburg-Essen (CeNIDE) (Germany); Li Zian [University of Duisburg-Essen, Faculty of Physics and Center for Nanointegration Duisburg-Essen (CeNIDE) (Germany); Yuan Ying; Krueger, Michael [University of Freiburg, Department of Microsystems Engineering and Freiburg Materials Research Centre (Germany); Farle, Michael [University of Duisburg-Essen, Faculty of Physics and Center for Nanointegration Duisburg-Essen (CeNIDE) (Germany); Winterer, Markus [University of Duisburg-Essen, Nanoparticle Process Technology, Faculty of Engineering and Center for Nanointegration Duisburg-Essen (CeNIDE) (Germany); Vander Elst, Luce; Muller, Robert N. [University of Mons, Department of General, Organic and Biomedical Chemistry NMR and Molecular Imaging Laboratory (Belgium); Wende, Heiko [University of Duisburg-Essen, Faculty of Physics and Center for Nanointegration Duisburg-Essen (CeNIDE) (Germany)

    2013-05-15

    Biocompatible magnetic nanoparticles have been found promising in several biomedical applications for tagging, imaging, sensing and separation in recent years. In this article, a systematic study of the design and development of surface-modification schemes for silica-coated iron oxide nanoparticles (IONP) via a one-pot, in situ method at room temperature is presented. Silica-coated IONP were prepared in a water-in-oil microemulsion, and subsequently the surface was modified via addition of organosilane reagents to the microemulsion system. The structure and the morphology of the as synthesized nanoparticles have been investigated by means of transmission electron microscopy (TEM) and measurement of N{sub 2} adsorption-desorption. Electron diffraction and high-resolution transmission electron microscopic (TEM) images of the nanoparticles showed the highly crystalline nature of the IONP structures. Nitrogen adsorption indicates microporous and blocked-microporous structures for the silica-coated and amine functionalized silica-coated IONP, respectively which could prove less cytotoxicity of the functionalized final product. Besides, the colloidal stability of the final product and the presence of the modified functional groups on top of surface layer have been proven by zeta-potential measurements. Owing to the benefit from the inner IONP core and the hydrophilic silica shell, the as-synthesized nanocomposites were exploited as an MRI contrast enhancement agent. Relaxometric results prove that the surface functionalized IONP have also signal enhancement properties. These surface functionalized nanocomposites are not only potential candidates for highly efficient contrast agents for MRI, but could also be used as ultrasensitive biological-magnetic labels, because they are in nanoscale size, having magnetic properties, blocked-microporous and are well dispersible in biological environment.

  12. Sonochemical and sustainable synthesis of graphene-gold (G-Au) nanocomposites for enzymeless and selective electrochemical detection of nitric oxide.

    Science.gov (United States)

    Geetha Bai, Renu; Muthoosamy, Kasturi; Zhou, Meifang; Ashokkumar, Muthupandian; Huang, Nay Ming; Manickam, Sivakumar

    2017-01-15

    In this study, a sonochemical approach was utilised for the development of graphene-gold (G-Au) nanocomposite. Through the sonochemical method, simultaneous exfoliation of graphite and the reduction of gold chloride occurs to produce highly crystalline G-Au nanocomposite. The in situ growth of gold nanoparticles (AuNPs) took place on the surface of exfoliated few-layer graphene sheets. The G-Au nanocomposite was characterised by UV-vis, XRD, FTIR, TEM, XPS and Raman spectroscopy techniques. This G-Au nanocomposite was used to modify glassy carbon electrode (GCE) to fabricate an electrochemical sensor for the selective detection of nitric oxide (NO), a critical cancer biomarker. G-Au modified GCE exhibited an enhanced electrocatalytic response towards the oxidation of NO as compared to other control electrodes. The electrochemical detection of NO was investigated by linear sweep voltammetry analysis, utilising the G-Au modified GCE in a linear range of 10-5000μM which exhibited a limit of detection of 0.04μM (S/N=3). Furthermore, this enzyme-free G-Au/GCE exhibited an excellent selectivity towards NO in the presence of interferences. The synergistic effect of graphene and AuNPs, which facilitated exceptional electron-transfer processes between the electrolyte and the GCE thereby improving the sensing performance of the fabricated G-Au modified electrode with stable and reproducible responses. This G-Au nanocomposite introduces a new electrode material in the sensitive and selective detection of NO, a prominent biomarker of cancer.

  13. Flotation of cobalt bearing minerals from a mixed copper-cobalt oxidized ore

    OpenAIRE

    2012-01-01

    M.Tech. (Extraction Metallurgy) The techniques for the flotation of mixed copper and cobalt bearing oxide ores using the sulphidization method in order to recover the oxidized copper and cobalt bearing minerals have been well documented by previous researchers. These processes have been successfully implemented in many of the metallurgical plant operations in the Democratic Republic of Congo (DRC). The mixed copper and cobalt oxidised ores from this region present significant chal-lenges t...

  14. Study on Mg/Fe Mixed Oxides Derived from Hydrotalite as De—SOx Catalyst

    Institute of Scientific and Technical Information of China (English)

    GuangLanZHUO; YinFeiCHEN; 等

    2002-01-01

    A novel class of desulfurization agent derived from hydrotalcite has been developed and its activity for SOx uptake have been investigated. The results showed that the Mg/Fe mixed oxide having high SOx uptake ability at a broad reaction temperature (e.g.673K-973K). The Mg/Fe ratio of the mixed oxide strongly affect the desulfurization role of the material and it can be used repeatly without much loss of SOx uptake ability.

  15. Study on Mg/Fe Mixed Oxides Derived from Hydrotalcite as De-SOx Catalyst

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A novel class of desulfurization agent derived from hydrotalcite has been developed and its activity for Sox uptake have been investigated. The results showed that the Mg/Fe mixed oxide having high Sox uptake ability at a broad reaction temperature (e.g. 673K ~ 973K). The Mg/Fe ratio of the mixed oxide strongly affect the desulfurization role of the material and it can be used repeatly without much loss of Sox uptake ability.

  16. Temperature-driven growth of reduced graphene oxide/copper nanocomposites for glucose sensing

    Science.gov (United States)

    Zhang, Qi; Wu, Zhong; Xu, Chen; Liu, Lei; Hu, Wenbin

    2016-12-01

    A one-spot method was developed for the synthesis of graphene sheet decorated with copper nanoparticles using different reduction temperatures via a molecular level mixing process. Here, we demonstrate that the reduction temperature is a crucial determinant of the properties of reduced graphene oxide (RGO)/metal composite and its electrocatalytic application in glucose sensing. To show this, we prepared a series of RGO/Cu composites at different reduction temperatures and examined the change rules of size, loading and dispersion of Cu particles, and the reduction extent of the RGO. Results showed that the Cu particle size increased with increasing reduction temperatures due to the Ostwald ripening process. Meanwhile, the Cu loading decreased with increasing reduction temperatures and the aggregation had not appeared in the high Cu loading situation. Additionally, the increasing reduction temperatures led to the decreasing concentrations of various oxygen-containing functional group of RGO with various degrees. The cyclic voltammogram showed that the RGO/metal composites fabricated under lower reduction temperatures exhibited higher electrocatalytic activity for glucose sensing, which was attributed to the higher surface area from larger loading of RGO/metal composites with smaller particle size. It can be concluded that the above factors play more significant roles in electrocatalytic efficiency than the decreased electron transfer rate between RGO and Cu within a certain range. These results highlight the importance of the reduction temperature influencing the properties of the RGO/metal composite and its application. We believe that these findings can be of great value in the further developing RGO/metal-based sensors for electrochemical detection of different analytes in emerging fields.

  17. Enhanced energy storage and suppressed dielectric loss in oxide core-shell-polyolefin nanocomposites by moderating internal surface area and increasing shell thickness.

    Science.gov (United States)

    Fredin, Lisa A; Li, Zhong; Ratner, Mark A; Lanagan, Michael T; Marks, Tobin J

    2012-11-20

    Dielectric loss in metal oxide core/Al(2)O(3) shell polypropylene nanocomposites scales with the particle surface area. By moderating the interfacial surface area between the phases and using increasing shell thicknesses, dielectric loss is significantly reduced, and thus the energy stored within, and recoverable from, capacitors fabricated from these materials is significantly increased, to as high as 2.05 J/cm(3).

  18. Conversion of Russian weapon-grade plutonium into oxide for mixed oxide (MOX) fuel fabrication

    Energy Technology Data Exchange (ETDEWEB)

    Glagovski, E.; Zakharkin, B. [A.A. Bochvar All-Russian Research Institute of Inorganic Materials, Russian Research Center, Moscow (Russian Federation); Kolotilov, Y. [Specialized State Design Institute, GSPI, Moscow (Russian Federation); Glagolenko, Y.; Skobtsov, A. [Mayak Production Association, Ozyorsk (Russian Federation); Zygmunt, S.; Mason, C.; Hahn, W.; Durrer, R. [Los Alamos National Lab., Nuclear Materials and Technology Div. NMT, Los Alamos, N.M. (United States); Thomas, S. [National Nuclear Security Administration, Washington DC (United States); Sicard, B.; Brossard, P.; Herlet, N. [CEA Marcoule 30 (France); Fraize, G.; Villa, A. [Cogema, 78 - Saint Quentin en Yvelines (France)

    2001-07-01

    Progress has been made in the Russian Federation towards the conversion of Russian weapons-grade plutonium (W-Pu) into plutonium oxide (PuO{sub 2}) suitable for further manufacture into mixed oxide (MOX) fuels. This program is funded both by French Commissariat at the Atomic Energy (CEA) and the US National Nuclear Security Administration (NNSA). The French program was started in the frame of the two cooperation agreements signed between Russian Federation and France in November 1992 concerning dismantling of nuclear weapons and the use of their nuclear materials for civilian purposes. The US program was started in 1998 in response to US proliferation concerns and the acknowledged international need to decrease available W-Pu. Russia has selected both the conversion process and the manufacturing site. This paper discusses the present state of development towards fulfilling this mission: the demonstration plant designed to process small amounts of Pu and validate all process stages and the industrial plant that will process up to 5 metric tons of Pu per year. (author)

  19. Titanium oxide modification with oxides of mixed cobalt valence for photo catalysis

    Energy Technology Data Exchange (ETDEWEB)

    Alanis O, R.; Jimenez B, J., E-mail: jaime.jimenez@inin.gob.m [ININ, Departamento de Quimica, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2010-07-01

    In the present work, heterogenous photo catalysis, a technique often used for organic compound degradation toxic in water, was used. The photo catalyst most often used in this technique is TiO{sub 2}, which due to its physical and chemical properties, can degrade a great number of organic compounds. In addition, in recent years it has been verified that the doping of semiconductors with metals or metallic oxides increases the photo catalytic activity of these semiconductors, which is why it was proposed for doping by the impregnating method using commercial TiO{sub 2} synthesized by the Degussa company (TiO{sub 2} Degussa P25) with and oxide of mixed cobalt valence (Co{sub 3}O{sub 4}) synthesized using the sol-gel method. The synthesized photo catalyst TiO{sub 2}/Co{sub 3}O{sub 4} was characterized by the techniques of X-ray diffraction, scanning electronic microscopy, Raman spectroscopy and finally, photo catalytic tests by means of the degradation of methylene blue. (Author)

  20. Preparation of graphene oxide/chitosan/FeOOH nanocomposite for the removal of Pb(II) from aqueous solution.

    Science.gov (United States)

    Sheshmani, Shabnam; Akhundi Nematzadeh, Mehrnaz; Shokrollahzadeh, Soheila; Ashori, Alireza

    2015-09-01

    In the present study, a graphene oxide/chitosan/FeOOH (GO/Ch/FeOOH) nanostructured composite was prepared and used as an adsorbent for the removal of Pb(II) ions from aqueous solution. The nanocomposite was characterized by FT-IR, XRD, and SEM techniques. Several important parameters influencing the adsorption of Pb(II) ions such as pH (3-7), temperature (25-80 °C), shaking speed (150-800 rpm), contact time (10-70 min), and sorbent mass (10-100 mg) were studied. The results showed that, benefiting from the surface property of graphene oxide, the abundant amino and hydroxyl functional groups of chitosan, the adsorbent provides adequate and versatile adsorption for the Pb(II) ions under investigation. The batch adsorption experiments showed that the adsorption of the Pb(II) is considerably dependent on pH of milieu, amount of adsorbent, and contact time. The Freundlich and Langmuir adsorption models were used for the mathematical description of adsorption equilibrium and isotherm constants. Both models were applicable for the description of Pb(II) adsorption isotherm in the concentration range studied. However, Langmuir model showed higher correlation coefficient (R(2)) than Freundlich model. The study suggests that the GO/Ch/FeOOH is a promising nano adsorbent for the removal of Pb(II) ions from aqueous solution.

  1. Hierarchical hybrid of Ni3N/N-doped reduced graphene oxide nanocomposite as a noble metal free catalyst for oxygen reduction reaction

    Science.gov (United States)

    Zhao, Qi; Li, Yingjun; Li, Yetong; Huang, Keke; Wang, Qin; Zhang, Jun

    2017-04-01

    Novel nickel nitride (Ni3N) nanoparticles supported on nitrogen-doped reduced graphene oxide nanosheets (N-RGOs) are synthesized via a facile strategy including hydrothermal and subsequent calcination methods, in which the reduced graphene oxide nanosheets (RGOs) are simultaneously doped with nitrogen species. By varying the content of the RGOs, a series of Ni3N/N-RGO nanocomposites are obtained. The Ni3N/N-RGO-30% hybrid nanocomposite exhibits superior catalytic activity towards oxygen reduction reaction (ORR) under alkaline condition (0.1 M KOH). Furthermore, this hybrid catalyst also demonstrates high tolerance to methanol poisoning. The RGO containing rich N confers the nanocomposite with large specific surface area and high electronic conduction ability, which can enhance the catalytic efficiency of Ni3N nanoparticles. The enhanced catalytic activity can be attributed to the synergistic effect between Ni3N and nitrogen doped reduced graphene oxide. In addition, the sufficient contact between Ni3N nanoparticles and the N-RGO nanosheets simultaneously promotes good nanoparticle dispersion and provides a consecutive activity sites to accelerate electron transport continuously, which further enhance the ORR performance. The Ni3N/N-RGO may be further an ideal candidate as efficient and inexpensive noble metal-free ORR electrocatalyst in fuel cells.

  2. Manganese-incorporated iron(III) oxide-graphene magnetic nanocomposite: synthesis, characterization, and application for the arsenic(III)-sorption from aqueous solution

    Science.gov (United States)

    Nandi, Debabrata; Gupta, Kaushik; Ghosh, Arup Kumar; De, Amitabha; Banerjee, Sangam; Ghosh, Uday Chand

    2012-12-01

    High specific surface area of graphene (GR) has gained special scientific attention in developing magnetic GR nanocomposite aiming to apply for the remediation of diverse environmental problems like point-of-use water purification and simultaneous separation of contaminants applying low external magnetic field (water. Fabrication of magnetic manganese-incorporated iron(III) oxide (Mn x 2+Fe2- x 3+O4 2-) (IMBO)-GR nanocomposite is reported by exfoliating the GR layers. Latest microscopic, spectroscopic, powder X-ray diffraction, BET surface area, and superconducting quantum interference device characterizations showed that the material is a magnetic nanocomposite with high specific surface area (280 m2 g-1) and pore volume (0.3362 cm3 g-1). Use of this composite for the immobilization of carcinogenic As(III) from water at 300 K and pH 7.0 showed that the nanocomposite has higher binding efficiency with As(III) than the IMBO owing to its high specific surface area. The composite showed almost complete (>99.9 %) As(III) removal (≤10 μg L-1) from water. External magnetic field of 0.3 T efficiently separated the water dispersed composite (0.01 g/10 mL) at room temperature (300 K). Thus, this composite is a promising material which can be used effectively as a potent As(III) immobilizer from the contaminated groundwater (>10 μg L-1) to improve drinking water quality.

  3. Nanocomposites of gold nanoparticles and graphene oxide towards an stable label-free electrochemical immunosensor for detection of cardiac marker troponin-I.

    Science.gov (United States)

    Liu, Guozhen; Qi, Meng; Zhang, Yin; Cao, Chaomin; Goldys, Ewa M

    2016-02-25

    A stable label-free amperometric immunosensor is presented based on gold nanoparticles and graphene oxide nanocomposites for detection of cardiac troponin-I in the early diagnosis of myocardial infarction. For designing of the sensing platform, firstly the nanocomposites based on GO and AuNPs were prepared and anchored on electrode surfaces. The formed nanocomposites provided a platform with big surface area for loading anti-cTnI capture antibody, and worked as a bridge for fast electron transfer subsequently increased the sensitivity. Moreover, the linkages between AuNP, GO, and electrodes were based on covalent bonding by aryldiazonium salt coupling chemistry, which favors the stability of the sensing interface. Finally, the anti-cTnI detection antibody was immobilized on GO tailored with ferrocene molecules, functioning as the signal reporter for the detection of cTnI. The modification process was monitored using electrochemistry, SEM, XPS. The herein immunosensor demonstrates a good selectivity and high sensitivity against human-cTnI, and is capable of detecting cTnI at concentrations as low as 0.05 ng mL(-1), which is 100 times lower than that possible by conventional methods. It is potential to design the portable sensing platform based on AuNPs and GO nanocomposites for future point-of-care diagnostics.

  4. Improving the drug delivery characteristics of graphene oxide based polymer nanocomposites through the "one-pot" synthetic approach of single-electron-transfer living radical polymerization

    Science.gov (United States)

    Gao, Peng; Liu, Meiying; Tian, Jianwen; Deng, Fengjie; Wang, Ke; Xu, Dazhuang; Liu, Liangji; Zhang, Xiaoyong; Wei, Yen

    2016-08-01

    Graphene oxide (GO) based polymer nanocomposites have attracted extensive research interest recently for their outstanding physicochemical properties and potential applications. However, surface modification of GO with synthetic polymers has demonstrated to be trouble for most polymerization procedures are occurred under non-aqueous solution, which will in turn lead to the restacking of GO. In this work, a facile and efficient "one-pot" strategy