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2011

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Articles 91 - 108 of 108

Full-Text Articles in Materials Chemistry

Novel Anion Exchange Membranes Base On Copolymer Of 2-(Diethylamino) Ethyl Methacrylate And Fluoro-Polyacrylate For Alkaline Direct Methanol Fuel Cells, Yan-Mei Zhang, Jun Fang, Ge Yan, Yong-Ze Zhuang Feb 2011

Novel Anion Exchange Membranes Base On Copolymer Of 2-(Diethylamino) Ethyl Methacrylate And Fluoro-Polyacrylate For Alkaline Direct Methanol Fuel Cells, Yan-Mei Zhang, Jun Fang, Ge Yan, Yong-Ze Zhuang

Journal of Electrochemistry

Anion exchange membrane fuel cells,which use anion exchange membranes as polyelectrolytes,have attracted more and more research interests recently.In this work,a series of hydroxyl-conducting anion-exchange membranes based on the copolymer of 2-(Diethylamino)ethyl methacrylate and fluoro-polyacrylate were prepared by radical polymerization,and their potential applications in alkaline fuel cells were assessed.It was shown that the ionic conductivity of the membranes reached 10-2 S·cm-1 at room temperature,while the methanol permeability was lower than 10-7 cm2·s-1.The maximum power density of fuel cell assembled with this membrane was achieved to be 43.2 mW·cm-2 at room temperature,indicating possible application …


Applications Of Raman Spectroscopy Technique In Lithium Ion Batteries, Liang Zhao, Yong-Sheng Hu, Hong Li, Zhao-Xiang Wang, Hong-Xing Xu, Xue-Jie Huang, Li-Quan Chen Feb 2011

Applications Of Raman Spectroscopy Technique In Lithium Ion Batteries, Liang Zhao, Yong-Sheng Hu, Hong Li, Zhao-Xiang Wang, Hong-Xing Xu, Xue-Jie Huang, Li-Quan Chen

Journal of Electrochemistry

The Raman spectroscopy has been widely used in the study of lithium ion batteries.In this short review,we gave some examples of the applications of Raman spectroscopy in the study of electrode materials including carbonaceous materials,spinel LiMxMn2-x O4,LiFePO4,as well as polymer electrolytes,room temperaturemolten salt electrolytes and the solid-electrolyte interphase layers.The advantages and disadvantages of the ex-situ and in-situ Raman spectrum techniques are discussed.Using new Raman techniques to investigate Li-ion batteries are suggested.


Electrooxidation Of Methanol On Multilayer Films Of Polypyrrole-Platinum Electrode, Ling Zhang, Long-Zhen Zheng Feb 2011

Electrooxidation Of Methanol On Multilayer Films Of Polypyrrole-Platinum Electrode, Ling Zhang, Long-Zhen Zheng

Journal of Electrochemistry

Multilayer films of polypyrrole-platinum electrode were fabricated by cyclic voltammetric technique.Electro-oxidation of methanol on this electrode was investigated with the aid of cyclic voltammetry and chronoamperometry.Results demonstrated that the multilayer of polypyrrole-platinum electrode behaved better electrocatalytic performance for electro-oxidaton of methanol and better poison resistant.Furthermore,with the increase of deposited platinum loadings,the rate controlling step on electro-oxidation reaction of methanol was changed from CO oxidation to sorption-desorption of hydrogen.


Electrochemical Capacitive Performance Of Polyaniline Electrode With Different Electrolytes, Yong-Tao Tan, Fen Ran, Ling-Ren Wang, Ji Liu, Ling-Bin Kong, Yong-Chun Luo, Long Kang Feb 2011

Electrochemical Capacitive Performance Of Polyaniline Electrode With Different Electrolytes, Yong-Tao Tan, Fen Ran, Ling-Ren Wang, Ji Liu, Ling-Bin Kong, Yong-Chun Luo, Long Kang

Journal of Electrochemistry

The polyaniline(PANi) for supercapacitor was prepared by chemical-oxidative polymerization.The SEM,FTIR data and electrochemical performance showed that,polyaniline nanoparticles were formed which were about 50 nm;the specific capacitances of PANi were 404 F/g,208 F/g and 279 F/g in 1 mol/L H2SO4,NaNO3 and KOH,respectively,when the current density was 5 mA/cm2.The concentrations of H2SO4 increased to 2 mol/L or 6 mol/L,the capacitances decreased to 330 F/g or 248 F/g.


Preparation And Electrochemical Properties Of Sn Thin Film As Anode Materials For Lithium-Ion Batteries, Hong-Mei Bai, Zhan-Liang Tao, Fang-Yi Cheng, Jun Chen Feb 2011

Preparation And Electrochemical Properties Of Sn Thin Film As Anode Materials For Lithium-Ion Batteries, Hong-Mei Bai, Zhan-Liang Tao, Fang-Yi Cheng, Jun Chen

Journal of Electrochemistry

Sn thin films as the anode materials of Li-ion batteries were prepared by vacuum-evaporation method on the copper foam substrate. The phase structure,surface morphology and electrochemical property of the as-prepared films were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM), and galvanostatic cycling. The results showed that three-dimensional structure of copper foam substrate enhanced the adhesion strength between the active material and the substrate, under the same substrate temperature, the particles became bigger with the increasing of evaporation time, while their electrochemical property decreased, under the same evaporation time, the particles didn′t changed obviously with the increasing of substrate temperature,while their cycle …


Electrocatalytic Oxidation Of Hydrazine At Rutin Carbon Nanotubes Modified Electrode, Hong-Fang Zhang, Qing-Lin Sheng, Jian-Bin Zheng Feb 2011

Electrocatalytic Oxidation Of Hydrazine At Rutin Carbon Nanotubes Modified Electrode, Hong-Fang Zhang, Qing-Lin Sheng, Jian-Bin Zheng

Journal of Electrochemistry

The electrochemical behavior and electrocatalytic oxidation of hydrazine on rutin multiwall carbon nanotubes modified glassy carbon electrode were studied by cyclic voltammetry.The experimental results indicated that the electrode exhibits good electrocatalytic activity to hydrazine at a reduced oxidation potential of 262 mV.The amperometric response of the modified electrode showed linear increase after successive addition of hydrazine in the concentration range of 2.5×10-6~1.0×10-4 mol·L-1 with a detection limit of 5×10-7 mol·L-1.


Electrochemical Double-Layer Capacitors Using Phenolic Resin-Based Carbon Fibers, Rong Xue, Jing-Wang Yan, Ying Tian, Bao-Lian Yi Feb 2011

Electrochemical Double-Layer Capacitors Using Phenolic Resin-Based Carbon Fibers, Rong Xue, Jing-Wang Yan, Ying Tian, Bao-Lian Yi

Journal of Electrochemistry

Phenolic resin-based activated carbon fiber(ACF) was prepared by KOH activation.The electrochemical properties of pulverized phenolic resin-based carbon fiber(P-ACF) were examined in 6 mol·L-1 KOH compared with that of the original ACF.P-ACF exhibited a better capacitive behavior and showed a larger specific capacitance(200 F·g-1) as well as a lower capacitance decrease at high current densities.The pore resistance for ion migration(Rp) in P-ACF was lower(2.96 Ω) than that in ACF(4.65 Ω).Pulverization increased the exposure of the cross section,lowered the contact resistance between the carbon fibers and decreased the pore resistance for ion migration.


Low-Temperature Performance Of Li-Ion Battery With Fluoroethylene Carbonate Electrolyte, Chun-Wei Yang, Feng Wu, Bo-Rong Wu, Yong-Huan Ren, Jing-Wen Yao Feb 2011

Low-Temperature Performance Of Li-Ion Battery With Fluoroethylene Carbonate Electrolyte, Chun-Wei Yang, Feng Wu, Bo-Rong Wu, Yong-Huan Ren, Jing-Wen Yao

Journal of Electrochemistry

The low temperature performance of electrolytes containing FEC including FEC+EMC, EC and PC, as well as the compatibility of electrolytes with LiFePO4 anode and with MCMB cathode were investigated.The electrolyte exhibits a high value of ionic conductivity at low temperature.The stability of cathode was enhanced by the formation of SEI film at 1.6 V as a result of FEC reaction. The infrared spectra showed that FEC can suppress decomposition of other solvents during SEI formation, and lower the resistance of SEI on MCMB cathode. The electrochemistry test indicates that Li-ion batteries with FEC electrolyte display high capacity at low …


Electrochemical Deposition Of Zinc Oxide Crystal Whiskers, Peng-Zeng Lu, Su Li, Jin-Qian Jia, Zhen-Hai Liang Feb 2011

Electrochemical Deposition Of Zinc Oxide Crystal Whiskers, Peng-Zeng Lu, Su Li, Jin-Qian Jia, Zhen-Hai Liang

Journal of Electrochemistry

Pine needle ZnO crystal whiskers were electrodeposited by anodization of zinc foil.The crystal whiskers were characterized by scanning electron microscopy(SEM) and X-ray diffraction(XRD) spectroscopy.The results show that the lengths and diameters of ZnO crystal whiskers are 200~300 nm and 20~50 nm,respectively,with the ratio of the length to diameter ranging from 10~15.The whiskers belong to wurtzite ZnO(JCPDS 36-1451) with good crystallinity and high purity.The crystalization behavior of ZnO was studied by cyclic voltammetry.The effects of the surface oxide layer at the zinc substrates and the [Zn(OH)4]2-concentration of the aqueous electrolyte on the formation of zinc oxide whiskers …


Micro- And Nanoparticles In Uv-Cured Thin Films, T. Christopher Corkery, Joseph Chan, Mike J. Idacavage, Elizabeth R. Gillies, Paul J. Ragogna Jan 2011

Micro- And Nanoparticles In Uv-Cured Thin Films, T. Christopher Corkery, Joseph Chan, Mike J. Idacavage, Elizabeth R. Gillies, Paul J. Ragogna

Chemistry Presentations

No abstract provided.


Analysis Of Electrodeposited Nickel-Iron Alloy Film Composition Using Particle-Induced X-Ray Emission, Alyssa Frey, Nicholas Wozniak, Timothy Nagi, Matthew Keller, J. Mark Lunderberg, Graham F. Peaslee, Paul Deyoung, Jennifer R. Hampton Jan 2011

Analysis Of Electrodeposited Nickel-Iron Alloy Film Composition Using Particle-Induced X-Ray Emission, Alyssa Frey, Nicholas Wozniak, Timothy Nagi, Matthew Keller, J. Mark Lunderberg, Graham F. Peaslee, Paul Deyoung, Jennifer R. Hampton

Faculty Publications

The elemental composition of electrodeposited NiFe thin films was analyzed with particle-induced X-ray emission (PIXE). The thin films were electrodeposited on polycrystalline Au substrates from a 100mM NiSO4, 10 mM FeSO4, 0.5M H3BO3, and 1M Na2SO4 solution. PIXE spectra of these films were analyzed to obtain relative amounts of Ni and Fe as a function of deposition potential and deposition time. The results show that PIXE can measure the total deposited metal in a sample over at least four orders of magnitude with similar fractional uncertainties. The technique is …


Heat Recovery Mechanism In The Excitation Of Radiative Polaritons By Broadband Infrared Radiation In Thin Oxide Films, Anita J. Vincent-Johnson, Kyle A. Vasquez, John E. Bridstrup, Andrew E. Masters, Xiaofeng Hu, Giovanna Scarel Jan 2011

Heat Recovery Mechanism In The Excitation Of Radiative Polaritons By Broadband Infrared Radiation In Thin Oxide Films, Anita J. Vincent-Johnson, Kyle A. Vasquez, John E. Bridstrup, Andrew E. Masters, Xiaofeng Hu, Giovanna Scarel

Department of Physics and Astronomy - Faculty Scholarship

This work probes radiative polaritons in thin oxide layers as a mean to capture and absorb broadband infrared radiation and transform it into heat. A heat recovery mechanism, based on the Seebeck effect, is used as the tool of the investigation. Heat production challenges the current understanding which views the excitation of radiative polaritons as only accompanied by the emission of electromagnetic radiation. The heat recovery mechanism presented here can inspire the design of infrared energy harvesting devices, similar to photovoltaic cells, and other devices to convert energy from a wide range of the electromagnetic radiation spectrum using thermoelectric power …


Fabrication And Catalytic Property Of Cerium Oxide Nanomaterials, Keren Jiang Jan 2011

Fabrication And Catalytic Property Of Cerium Oxide Nanomaterials, Keren Jiang

Department of Chemistry: Dissertations, Theses, and Student Research

Cerium oxide, or ceria (CeOx: x = 1.5 to 2), has been widely used as a heterogeneous catalyst. Ceria has several properties make it high catalytic active: the fluctuating valence of cerium, the high oxygen storage capacity and high oxygen mobility in the nonstoichiometric ceria. With the high abundance of cerium on earth crust, ceria is a highly effective alternative of the noble metal catalysts. Research has been focused on designing nanostructured ceria and ceria related materials in recent years. The catalytic activity of ceria can be enhanced by the nanoscale effect which can be applied for various …


Elastic Properties Of Poly(Vinyldene Fluoride) (Pvdf) Crystals: A Density Functional Theory Study, Yong Pei, Xiao Cheng Zeng Jan 2011

Elastic Properties Of Poly(Vinyldene Fluoride) (Pvdf) Crystals: A Density Functional Theory Study, Yong Pei, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

We computed structural and elastic properties of totally nine phases of poly(vinyldene fluoride) (PVDF) crystals using the density-functional theory (DFT) method with and without inclusion of the dispersion corrections. In addition to the four known crystalline forms, mechanic properties of five theoretically predicted crystalline forms of PVDF are also investigated. The all-trans form Ip exhibits the largest cohesive energy, bulk, and Young’s modulus among the nine crystalline forms. The DFT calculations suggest that the δ crystalline forms (IIIau, IIIpu, IIIpd, and IIIad) possess poor chain rigidity among the nine PVDF …


Structure Evolution Of Gold Cluster Anions Between The Planar And Cage Structures By Isoelectronic Substitution: AuN− (N = 13–15) And MauN− (N = 12–14; M = Ag, Cu), Rhitankar Pal, Lei-Ming Wang, Wei Huang, Lai-Sheng Wang, Xiao Cheng Zeng Jan 2011

Structure Evolution Of Gold Cluster Anions Between The Planar And Cage Structures By Isoelectronic Substitution: AuN− (N = 13–15) And MauN− (N = 12–14; M = Ag, Cu), Rhitankar Pal, Lei-Ming Wang, Wei Huang, Lai-Sheng Wang, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

The structural and electronic effects of isoelectronic substitution by Ag and Cu atoms on gold cluster anions in the size range between 13 and 15 atoms are studied using a combination of photoelectron spectroscopy and first-principles density functional calculations. The most stable structures of the doped clusters are compared with those of the undoped Au clusters in the same size range. The joint experimental and theoretical study reveals a new C3v symmetric isomer for Au13 −, which is present in the experiment, but has hitherto not been recognized. The global minima of Au14 − and Au …


A Practical Photoelectrochemical Cell Using Nonprecious Metal Electrodes, Patrick Enright, Tony Betts, John Cassidy Jan 2011

A Practical Photoelectrochemical Cell Using Nonprecious Metal Electrodes, Patrick Enright, Tony Betts, John Cassidy

Articles

Abstract: Photoelectrochemical cells (PECs) can be used to harvest light from the oxidation of dissolved organic matter. Similar to fuel cells but requiring light to operate, PECs contain a light assisted electrode that oxidises electron rich materials (anode); these electrons then flow to a typically Pt cathode where O2 is normally the electron acceptor. In this work a PEC cell containing inexpensive materials was shown to (a) mineralise typical organic compounds present in waste water and (b) produce electricity from their decomposition. The PEC cell consisted of a TiO2 coated conducting ink anode exposed to a light source, …


Fabrication And Preliminary Characterization Of Hydrophobic Silica Aerogel Films For Oil Remediation Studies, Ellen Yang Jan 2011

Fabrication And Preliminary Characterization Of Hydrophobic Silica Aerogel Films For Oil Remediation Studies, Ellen Yang

Pomona Senior Theses

Due to the potential of oil sorbents for oil spill clean-up, hydrophobic silica-based aerogel thin films have been synthesized and characterized by various methods. Aerogels were prepared using a two-step acid/base sol-gel process and functionalized with trimethylchlorosilane in hexane, followed by drying in ambient conditions. After film deposition by spin-coating, samples were characterized by scanning electron microscopy, nitrogen adsorption analysis (BET surface area = 377.66 m2 /g), and variable-angle spectroscopic ellipsometry (thickness of 287.00 ± 0.85 nm, refractive index of 1.08, porosity of 80.9%). Unlike previous studies with aerogel films, quartz crystal microbalance with dissipation monitoring (QCM-D) was applied to …


Growth And Characterization Of Nanoscale Thin Films, Erik Thomas Wolter Jan 2011

Growth And Characterization Of Nanoscale Thin Films, Erik Thomas Wolter

Honors Program Theses

Thin manganese films were grown by thermal evaporation in high vacuum. The growth rate was varied to determine how the growth rate affects the continuity of ultra-thin films. The resistance was measured with the two-point method in situ and the data was recorded digitally. The resistance was converted to resistivity and this was plotted against thickness. It was found that resistivity decreases exponentially as the film begins to form in islands. The film reaches a critical thickness as the islands coalesce and the data can then be fitted with Fuchs’ equation. The resistivity continues to decrease but the minimum resistivity …