Open Access. Powered by Scholars. Published by Universities.®

Materials Chemistry Commons

Open Access. Powered by Scholars. Published by Universities.®

2009

PDF

Discipline
Institution
Keyword
Publication
Publication Type

Articles 1 - 30 of 112

Full-Text Articles in Materials Chemistry

Investigation Of Novel Thiol "Click" Reactions, Justin William Chan Dec 2009

Investigation Of Novel Thiol "Click" Reactions, Justin William Chan

Dissertations

The thio-Michael addition reaction is traditionally considered a base catalyzed reaction which involves high catalyst concentrations and long reaction times. This reaction utilizes potent, simple nucleophiles to catalyze the reaction, decreases the catalyst concentration and greatly increases the reaction times. The free radical mediated thiol-ene click reaction uses light or heat and an initiator to catalyze the rapid and quantitative addition of thiols to most electron rich enes without the formation of side products and in the absence of solvent. Recently, the thiol-ene click reaction has been exploited for these reasons in materials science and organic synthesis. The research herein …


Investigation Of The Relationship Between Polymer Structures And Thermal, Mechanical, Viscoelastic Properties, Ethem Kaya Dec 2009

Investigation Of The Relationship Between Polymer Structures And Thermal, Mechanical, Viscoelastic Properties, Ethem Kaya

Dissertations

The research presented in this dissertation involves four distinct areas: physical crosslinking systems, UV curable coatings for enhanced oxygen and carbon dioxide barrier properties, synthesis, and investigation of melting behavior/crystallinity relations of linear polyamides with long alkyl chains, and synthesis and characterization of cyclic diamides as precursors to linear polyamides 6 4.

The physical crosslinking section involves synthesis of monomers and polymers bearing cyclodextrin and adamantane pendent groups, and investigation of non-covalent interactions between these polymers (Chapter II). Two methacrylate monomers bearing cyclodextrin and adamantane were synthesized, and copolymerized with poly(ethylene glycol) methyl ether methacrylate. The specific interaction between copolymers …


Random And Block Copolymers Of Poly(Dodecamethyleneterephthalamide), Theodore Frank Novitsky Jr. Dec 2009

Random And Block Copolymers Of Poly(Dodecamethyleneterephthalamide), Theodore Frank Novitsky Jr.

Dissertations

The following dissertation focuses on the synthesis and characterization of poly(dodecamethylene terephthalamide) (PA-12,T) and novel copolymers. Chapter I details the synthesis of PA-12,T homopolymer by melt condensation polymerization. A series of homopolymers with different molecular weights were obtained by adjusting the stoichiometry of the polymerization using 1,12-diaminododecane, terephthalic acid and benzoic acid. End group 13C NMR spectroscopy resonances were obtained by correlating peak intensities with intrinsic viscosity values. From the NMR data, total end group concentrations and molecular weights were determined for each sample. The data exhibited a linear trend when plotting log (IV) versus log (Mn), and previously unknown …


Preparation And Characterization Of Thiol Based Polymeric Materials, Junghwan Shin Dec 2009

Preparation And Characterization Of Thiol Based Polymeric Materials, Junghwan Shin

Dissertations

The thiol click-type reaction is one of the most efficient chemical processes that can undergo at room temperature in the benign organic solvent providing excellent opportunity in the fabrication of new materials as well as development of new manufacturing processes. Moreover, the versatility of thiol click-type reactions with many different functional groups such as ene, yne, epoxy, isocyanate, and alkyl halide is the important aspect that should be differentiated from the classic azide-alkyne click chemistry. Although, there are tremendous studies on many areas using thiol click-type reactions, the efficiency and utilities for the material applications have been barely explored. Especially, …


Kinetic Studies Of The Sulfoxidation Of Aryl Methyl Sulfides By Trans-Dioxoruthenium(Vi) Porphyrin Complexes, Chris Abebrese Dec 2009

Kinetic Studies Of The Sulfoxidation Of Aryl Methyl Sulfides By Trans-Dioxoruthenium(Vi) Porphyrin Complexes, Chris Abebrese

Masters Theses & Specialist Projects

The development of an efficient, catalytically active, biomimetic model for cytochrome P-450 enzymes has been an area of intense research activity. Ruthenium porphyrin complexes have been the center of this research and have successfully been utilized, as catalysts, in major oxidation reactions such as the hydroxylation of alkanes, the epoxidation of alkenes and aromatic rings, and the N-oxidation of amines, among others. In this project, the kinetics of two-electron sulfoxidation of para-substituted phenyl methyl sulfides to the corresponding sulfoxides with well-characterized trans-dioxoruthenium(VI) porphyrin complexes were studied by rapid stopped-flow spectroscopy. The substituent effect in sulfides and in dioxoruthenium(VI) complexes were …


Off-Metal Synthesis Of Some Aryl Substituted Rhenium N5-Cyclopenta [C] Pyridazyl Complexes, James Leif Neathery Dec 2009

Off-Metal Synthesis Of Some Aryl Substituted Rhenium N5-Cyclopenta [C] Pyridazyl Complexes, James Leif Neathery

Masters Theses & Specialist Projects

Heterocyclic organic and organometallic compounds (e.g. polypyrrole), and their derivatives, have been of great interest for conductive polymers due to their novel properties and environmental stability as compared to non-aromatic analogs (e.g. polyacetylene). Our current interests focus upon the potential role of pyridazines in next generation electronic devices that utilize organics as the semiconducting material. Pyridazines, 6-membered aromatic rings with two adjacent nitrogens, are promising candidates for a variety of materials and commercial applications. These molecular electronic materials posses several advantages over traditional inorganic semiconducting materials including lower cost of production, higher processibility, and the ability to function on flexible …


Electrocatalytic Performance Of Carbon Supported Ir Catalysts With Different Ir Loadings For Ammonia Oxidation, Yu-Zhi Jiang, Qing-Mei Kong, Tian-Hong Lu, Yi-Ming Zhou, Ya-Wen Tang Nov 2009

Electrocatalytic Performance Of Carbon Supported Ir Catalysts With Different Ir Loadings For Ammonia Oxidation, Yu-Zhi Jiang, Qing-Mei Kong, Tian-Hong Lu, Yi-Ming Zhou, Ya-Wen Tang

Journal of Electrochemistry

The electrocatalytic performance of the Ir/C catalyst as the anodic catalyst in the amperometric and electrochemical NH3 sensor was investigated.The experimental results illustrated that in the NaClO4 neutral electrolyte,the electrocatalytic performance of the Ir/C catalyst for the NH3 oxidation is related to the Ir loading in the Ir/C catalyst.Among the Ir/C catalysts with different Ir loading,the best electrocatalytic activity,stability and sensitivity were achieved by the Ir/C catalyst with 10% Ir loadings.In addition,the current densities of the NH3 oxidation at the Ir/C catalysts with the different Ir loadings were linearly proportional to the NH3 concentration.The Ir/C catalyst has a potential application …


Cyclic Voltammetric And In-Situ Ftir Spectroscopic Studies Of Adsorption And Reduction Of No On Electrode Of Pt Nanoparticles, Qian Cheng, Yan-Xia Jiang, Dong-Mei Zeng, Shi-Gang Sun Nov 2009

Cyclic Voltammetric And In-Situ Ftir Spectroscopic Studies Of Adsorption And Reduction Of No On Electrode Of Pt Nanoparticles, Qian Cheng, Yan-Xia Jiang, Dong-Mei Zeng, Shi-Gang Sun

Journal of Electrochemistry

Adsorption and reduction of NO on electrode of Pt nanoparticles in acid solutions were studied by means of cyclic voltammetry(CV) and in-situ FTIR spectroscopy.The results indicated that the reduction of NO is a complicated process including the adsorption of NO on electrode surface.Two types of surface-bonded NO were determined on Pt nanoparticles.The weakly adsorbed NO was reduced between 0.6 V and-0.05 V,which yielded nitrous oxide(N2O) and ammonium(NH+4) as products;while the strongly bonded NO was reduced at more negative potentials between-0.05V and-0.15V,producing only NH4+ species.


Highly Durable Pt/Ruo_2/C Catalyst For The Cathode Of Direct Methanol Fuel Cells, Chun-Yu Du, Tao Dong, Ge-Ping Yin, Peng-Fei Shi Nov 2009

Highly Durable Pt/Ruo_2/C Catalyst For The Cathode Of Direct Methanol Fuel Cells, Chun-Yu Du, Tao Dong, Ge-Ping Yin, Peng-Fei Shi

Journal of Electrochemistry

Instability of the carbon-supported Pt(Pt/C) catalyst at the cathode is one of the key technical challenges for the development of Direct Methanol Fuel Cells(DMFCs).In this paper,an efficient approach to enhancing the stability of the cathode catalyst was explored by designing and synthesizing a novel nanocomposite support,RuO2 coated carbon black(RuO2/C).Firstly,a wet chemical method was employed to synthesize the RuO2/C nanocomposite,from which Pt/RuO2/C catalyst was further prepared by a microwave method.The morphology and crystalline structure of the RuO2/C support and Pt/RuO2/C catalyst were then characterized by TEM and XRD.Finally,the electrochemical performance of the RuO2/C support and Pt/RuO2/C catalyst was analyzed by cyclic …


Enhanced [Ru(Bpy)_3]~(2+)-Mediated Oxidation Of Guanine Prompted By Dhp, Bao-Lian Zhang, Wei Hong, Bao-Yi Lu, Hong Li Nov 2009

Enhanced [Ru(Bpy)_3]~(2+)-Mediated Oxidation Of Guanine Prompted By Dhp, Bao-Lian Zhang, Wei Hong, Bao-Yi Lu, Hong Li

Journal of Electrochemistry

The effects of dihexadecyl phosphate(DHP) and multi-walled carbon nanotubes(MWNTs) on the oxidation of guanine mediated by[Ru(bpy)3]2+ on the ITO electrode have been investigated by cyclic voltammetry and differential pulse voltammetry.The results showed that [Ru(bpy)3]2+ can mediate the oxidation.In the range from 0.01 to 0.15 mmol·L-1,peak currents for guanine oxidation mediated by [Ru(bpy)3]2+ increased with the rise of DHP concentrations.On the contrary,cationic surfactant HTAC has the ability to weaken the mediated oxidation of guanine.In addition,the oxidative mechanism of guanine mediated by [Ru(bpy)3]2+ with the participation of DHP is discussed.


Synthesis And Electrocatalytic Properties Of Ni-Pd/C Catalysts With Pd-Enriched Surface, Yu-Mei Chen, Zhi-Xiu Liang, Sheng-Li Chen Nov 2009

Synthesis And Electrocatalytic Properties Of Ni-Pd/C Catalysts With Pd-Enriched Surface, Yu-Mei Chen, Zhi-Xiu Liang, Sheng-Li Chen

Journal of Electrochemistry

The Ni-Pd alloy catalysts with Pd-enriched surface were synthesized through a modified polyol process.The synthesized materials were investigated by XRD and electrochemical methods,and tested as electrocatalysts for CH3OH-tolerant oxygen reduction.The results indicated that the synthesized Ni-Pd nanoparticles possess multiple phases containing Pd-Ni alloy and pure Ni.Comparing with Pd/C,the prepared Ni-Pd/C nanoparticles exhibited better resolved voltammetric peaks between the hydrogen absorption and adsorption,and positively shifted current peaks for the reduction of Pd oxide.The prepared Ni-Pd alloys with Pd-enriched surface have significantly enhanced ORR activity and improved CH3OH tolerance as comparing with Pd/C catalysts.


Preparation Of Pt Nanoflower/Zno Composites Arrays And Their Electrocatalysis For Methanol Oxidation, Li Gao, Yi-Feng E, Lou-Zhen Fan Nov 2009

Preparation Of Pt Nanoflower/Zno Composites Arrays And Their Electrocatalysis For Methanol Oxidation, Li Gao, Yi-Feng E, Lou-Zhen Fan

Journal of Electrochemistry

The Pt nanoflower/ZnO(PtNF/ZnO) nanorod composites arrays were electrochemically prepared by controlling the hydrophobicity and the hydrophilicity of ZnO nanorods arrays.The Pt nanoflowers grew on the tip of ZnO nanorods,which maintain the vertical array of Zno nanorods with a high degree of size uniformity and high surface area.Compared with Pt nanoparticle covered ZnO nanorod arrays,which were prepared by controlling the hydrophilicities of ZnO nanorods and Pt nanoparticles,the PtNF/ZnO displayed highest electrocatalytic activities for the oxidation of methanol.


Electrooxidation Of Formic Acid On Pd-Ni Alloy Film Electrode-The Effect Of Dealloying, Chao Wang, Fei-Fei Shi, Jin-Yi Wang, Han-Xuan Zhang, Wen-Bin Cai Nov 2009

Electrooxidation Of Formic Acid On Pd-Ni Alloy Film Electrode-The Effect Of Dealloying, Chao Wang, Fei-Fei Shi, Jin-Yi Wang, Han-Xuan Zhang, Wen-Bin Cai

Journal of Electrochemistry

A Pd-Ni alloy film was electrodeposited on Au disc electrode at a constant potential from a weakly basic bath containing PdCl2,NiSO4 and ethylenediamine.The as-deposited film was then subjected to potential cycling in a perchloric acid solution for surface dealloying treatment.The dealloyed Pd-Ni film electrode was examined for the electrocatalytic oxidation of formic acid,and compared with the as-deposited one as well as a Pd film electrode.The FE-SEM and electrochemical measurements on the Pd-Ni films revealed that the dealloying treatment caused a surface roughening and an increase in specific surface reaction area.The ICP-AES and XPS analyses demonstrated that the preferential dissolution of …


Electrocatalytic Activities Of Au-Mmni_(3.2)Al_(0.2)Mn_(0.6)Co_(1.00) For Borohydride Oxidation, Gui-Ling Wang, Jin-Cheng Liu, Ke-Ning Sun, Dian-Xue Cao Nov 2009

Electrocatalytic Activities Of Au-Mmni_(3.2)Al_(0.2)Mn_(0.6)Co_(1.00) For Borohydride Oxidation, Gui-Ling Wang, Jin-Cheng Liu, Ke-Ning Sun, Dian-Xue Cao

Journal of Electrochemistry

In this work,the electrocatalytic activities of MmNi3.2Al0.2Mn0.6Co1.0,NaOH treated MmNi3.2Al0.2Mn0.6Co1.0 and Au-MmNi3.2Al0.2Mn0.6Co1.0 obtained after NaOH treatment(Mm: misch metal) for NaBH4 oxidation were reported.The electrodes were prepared by electrodeposition,their morphologies were analysized by SEM,their electrocatalytic properties were studied by the linear sweeping test.It was found that the oxidation current density of the Au-MmNi3.2Al0.2Mn0.6Co1.0 was 60 mA·cm-2,it was 3.5 times higher than that at the MmNi3.2Al0.2Mn0.6Co1.0 electrode.In addition,the oxidation current density at the Au-MmNi3.2Al0.2Mn0.6Co1.0 electrode immersed in the electrolyte solution for 10 hours was 184 mA·cm-2.


Preparation Of Polyaniline/Polyester Conductive Fabric Via In-Situ Polymerization, Fang Na, Wei Wang Nov 2009

Preparation Of Polyaniline/Polyester Conductive Fabric Via In-Situ Polymerization, Fang Na, Wei Wang

Journal of Electrochemistry

The formation of PANI coating on the surface of PET fiber and fabric was obtained by in-situ polymerization method.The coating′s thickness was about 1~2 μm.Orthogonal test methodology was used to analyze the main factors of preparation of PANI / PET conductive fabric.The effects of the aniline monomer concentration,oxidant: aniline molar ratio,doping acid concentration and types,reaction time on the conductivities of the fabric were studied.The structure of the polymer were characterized by SEM,FTIR and XRD.The results indicated that there was uniform and continuous polyaniline film on the surface of polyester fabric.The contents of oxidation and reduction of polyaniline molecular chain structure …


Complex Reduction Preparation Of Carbon Supported Pd Nanoparticle Catalyst And Its Electrocatalysis For Formic Acid Oxidation, Wei He, Yong-Yin Kang, Chong Du, Zhi-Qing Zou, Xiao-Gang Zhang, Hui Yang Nov 2009

Complex Reduction Preparation Of Carbon Supported Pd Nanoparticle Catalyst And Its Electrocatalysis For Formic Acid Oxidation, Wei He, Yong-Yin Kang, Chong Du, Zhi-Qing Zou, Xiao-Gang Zhang, Hui Yang

Journal of Electrochemistry

A simple procedure involved the complexing of PdCl2 with sodium citrate followed by ethylene glycol reduction has been employed for the preparation of carbon-supported Pd nanoparticles(Pd/C).The XRD and TEM characterizations indicate that Pd nanoparticles with a small particle size were well-dispersed on carbon support.The mean particle sizes of the Pd/C catalysts were found to be increased from 2.7 to 5.8 nm with heat-treatments at different temperature.The mass activity of the Pd/C catalyst for formic acid electrooxidation increased with the decrease in Pd particle size.However,the specific activity increased with Pd particle size.Furthermore,the Pd/C catalyst with a particle size of ca.3.6 nm …


Research Progress Of Synergistic Effect Of Metal Oxides On Pt-Based Catalysts, Hui-Ping Yuan, Xun Guo, Xin-Ping Qiu, Wen-Tao Zhu, Li-Quan Chen Nov 2009

Research Progress Of Synergistic Effect Of Metal Oxides On Pt-Based Catalysts, Hui-Ping Yuan, Xun Guo, Xin-Ping Qiu, Wen-Tao Zhu, Li-Quan Chen

Journal of Electrochemistry

In this paper,the work of Pt-based catalysts modified by metal oxides as the anode catalysts of direct methanol fuel cell(DMFC) is reviewed.The relationship between the structure and the composition of the catalysts and the reaction mechanism,exiting problems and developing direction are discussed.


Electrocatalysis Of Myoglobin-Chitosan-Au Colloid Film Modified Glass Carbon Electrode, Yu-Hua Qin, Jun Guo, Hui Xu, Li-Heng Zhou, Sheng-Tian Wang Nov 2009

Electrocatalysis Of Myoglobin-Chitosan-Au Colloid Film Modified Glass Carbon Electrode, Yu-Hua Qin, Jun Guo, Hui Xu, Li-Heng Zhou, Sheng-Tian Wang

Journal of Electrochemistry

The cyclic voltammgram of Mb/AAO/Au Colloid/GCE shows a pair of well-defined and nearly reversible peaks at about-0.20 V(vs.Ag/AgCl) in 0.1 mol/L NaAc-HAc buffer(pH = 5.4),being the characteristic peaks of the Mb heme Fe(Ⅲ) / Fe(Ⅱ)redox couples.The electron transfer between Mb and the electrode was greatly enhanced under present testing conditions.The effects of scan rate,pH and buffers concentration on the electrochemical behaviors of Mb were studied in detail.Position of the Soret absorbance band suggested that Mb in chitosan-colloidal gold hept its secondary structure similar to the native states.Oxygen was catalytically reduced by Mb in chitosan-colloidal gold films.


Indirect Electrosynthesis Of Double Aldehyde Starch Using Pb-(Bro_3~-/Br~-) As Electro-Catalytic Mediator, Chen Ni-Na, Chen Ri-Yao, Xi Zheng, Chen Xiao, Zhen Chen Nov 2009

Indirect Electrosynthesis Of Double Aldehyde Starch Using Pb-(Bro_3~-/Br~-) As Electro-Catalytic Mediator, Chen Ni-Na, Chen Ri-Yao, Xi Zheng, Chen Xiao, Zhen Chen

Journal of Electrochemistry

In this paper,Nafion membrane was used as the separator in the electrolysis cell to indirectly electro-generating the double aldehyde starch(DAS) with BrO-3/Br-as a redox mediator and Pb as an anode.Effects of temperature,concentration of sulfuric acid and starch on the electro-oxidation of DAS were discussed.The steady state polarization curves were obtained.The experiment results showed that the current efficiency was over 50% when the electrolysis current density was 15mA/ cm2.


Progresses In Electrocatalysis Of Nanomaterials—Tuning The Surface Structure And Property Of Electrocatalysts, Yan-Xia Jiang, Na Tian, Zhi-You Zhou, Sheng-Pei Chen, Shi-Gang Sun Nov 2009

Progresses In Electrocatalysis Of Nanomaterials—Tuning The Surface Structure And Property Of Electrocatalysts, Yan-Xia Jiang, Na Tian, Zhi-You Zhou, Sheng-Pei Chen, Shi-Gang Sun

Journal of Electrochemistry

The property of an electrocatalyst depends strongly on its surface structure.The study of surface structure-catalytic functionality is the base of design and preparation of electrocatalysts of high activity,high stability and high selectivity at microstructure level.In this paper,based mainly on our results concering hydrogen and oxygen adsorption-desorption,ethylene glycol oxidation and CO2 reduction,the research progresses in tuning the surface structure and property of electrocatalysts are summarized.This paper overviews firstly the cyclic voltammetric characteristics,electrocatalytic properties of platinum single crystal planes lying on different crystallographic zones of the unit stereographic triangle of face-centered cubic(fcc) metals.Next,the innovation of electrochemical methods to control the surface structure …


Electrocatalysis In Polymer Electrolyte Membrane Fuel Cells, Li Li, Si-Guo Chen, Xue-Qiang Qi, Yao-Qiong Wang, Meng-Bo Ji, Lan-Lan Li, Zi-Dong Wei Nov 2009

Electrocatalysis In Polymer Electrolyte Membrane Fuel Cells, Li Li, Si-Guo Chen, Xue-Qiang Qi, Yao-Qiong Wang, Meng-Bo Ji, Lan-Lan Li, Zi-Dong Wei

Journal of Electrochemistry

This review presents the study of Chongqing University in electrocatalysis for polymer electrolyte membrane fuel cells(PEMFCs).Based on the understanding to the performance degradation of PEMFCs' catalysts,the university has being concentrated on how to increase the activity,stability and utility of noble metal catalysts.It covers the molecular design of near-surface alloy catalysts for improvement of activity to oxygen reduction reaction(ORR) and resistance to foreign poison species,selective deposition of Pt on the so-called "three-phase interface" for a high Pt utility,and invention of anti-flooding electrode against water flooding in the catalyst layer of the membrane assemble electrode(MEA),and so on.The catalytic mechanism of electrode reactions …


Platinum Modified With Hydrogen Molybdenum/Tungsten Bronze As Electrocatalysts For Direct Small Organic Molecule Fuel Cell, Wei-Shan Li, Li-Peng Tian, Jun-Hua Du, Hong-Liang Huang, Wei Li, Li-Xia Zhang, Hong-Yan Yang, Pan-Pan Guo, Zhi-Hui Zhou, Xing-De Xiang, Zhao Fu Nov 2009

Platinum Modified With Hydrogen Molybdenum/Tungsten Bronze As Electrocatalysts For Direct Small Organic Molecule Fuel Cell, Wei-Shan Li, Li-Peng Tian, Jun-Hua Du, Hong-Liang Huang, Wei Li, Li-Xia Zhang, Hong-Yan Yang, Pan-Pan Guo, Zhi-Hui Zhou, Xing-De Xiang, Zhao Fu

Journal of Electrochemistry

There are several problems that limit the application of direct small organic fuel cell,including the use of precious platinum and the activity loss of platinum due to the intermediates poisons from the oxidation of small organic molecules.These problems have attracted wide interest and many solutions have been proposed.We have developed a new method to reduce the platinum usage and improve its activity,based on the modification of platinum with hydrogen molybdenum/tungsten bronze(HxMo(W)O3,0


Enhanced Visible Light Photoelectrochemical Performances With Nitrogen Doped Tio_2 Nanowire Arrays, Xiao-Jun Lv, Yue-Ming Li, Hao Zhang, Da Chen, Hensel Jennifer, Z Zhang Jin, Jing-Hong Li Nov 2009

Enhanced Visible Light Photoelectrochemical Performances With Nitrogen Doped Tio_2 Nanowire Arrays, Xiao-Jun Lv, Yue-Ming Li, Hao Zhang, Da Chen, Hensel Jennifer, Z Zhang Jin, Jing-Hong Li

Journal of Electrochemistry

Self-organized anodic anatase TiO2nanowire arrays doped with nitrogen have been successfully fabri-cated and their photoelectrochemical(PEC) properties have been characterized and found to be substantially im-proved compared to undoped nanowires or commercial P25 nanoparticles.Photocurrent measured with monochro-matic incident light showed that the incident photon-to-current efficiency(IPCE,%) values of nanowire arrayelectrodes with or without N-doping were obviously higher than that of commercial P25 nanoparticle electrodes,and nitrogen-doped TiO2nanowire arrays(NTNA) had noticeable absorption in the visible region.The NTNAelectrodes showed the highest photocurrent density and power conversion efficiency under 100 mW/cm2visiblelight illumination.A maximumolphotoconversion efficiency of 0.52% was achieved for the NTNA sample at anapplied potential of …


Synthesis Of Α-Mno_2 Microspheres For The Application In Supercapacitor, Liang Wang, Gui-Chang Liu, Zhi-Cong Shi Nov 2009

Synthesis Of Α-Mno_2 Microspheres For The Application In Supercapacitor, Liang Wang, Gui-Chang Liu, Zhi-Cong Shi

Journal of Electrochemistry

The MnO2 microspheres were prepared through the oxidation of KMnO4 and MnCO3 microspheres precursor.The microstructure and supercapacitor properties of MnO2 were characterized by XRD,SEM and CV.The results show that MnO2 was in a poorly crystalline state with α-crystallographic form,the size of microspheres typically ranged from 0.5 to 2 μm.Loading 5 mg·cm-2 MnO2 microspheres had excellent capacitance behaviors in 2 mol·L-1(NH4)2SO4 solution.The specific capacitance was 135.6 F·g-1 with the scan rate at 2 mV·s-1,and 118.8 F·g-1 with the large scan rate at 100 mV/s.Coulumbic efficiency was still above 87.8% in the 500 cycles,and the specific capacitance of the 500th cycle was …


Spectroscopic Investigation Of The Anatase-To-Rutile Transformation Of Sol-Gel Synthesised Tio2 Photocatalysts, Nicholas Nolan, Suresh Pillai, Michael Seery Sep 2009

Spectroscopic Investigation Of The Anatase-To-Rutile Transformation Of Sol-Gel Synthesised Tio2 Photocatalysts, Nicholas Nolan, Suresh Pillai, Michael Seery

Articles

Among the three major phases in titania, anatase is reported to be a better photocatalytically active phase. Anatase to rutile transformations, under normal conditions, usually occurs at a temperatue range of 600- 700 °C. Various chemical additives have previously been employed to extend the anatase transition to higher temperatures. Effect of employing various concentrations of formic acid and water on phase transition has systematically been studied by XRD, FTIR and Raman spectroscopy. A considerably higher anatase phase (41%) has been obtained at 800 ºC and 10% anatase composition is retained after annealing the materials at 900 ºC for the optimised …


Electrochemically Induced Free Radical Polymerization Of Methacrylic Acid And Fabrication Of Amperometric Glucose Biosensor, Sheng Wang, Ying Lei, Kang Shi Aug 2009

Electrochemically Induced Free Radical Polymerization Of Methacrylic Acid And Fabrication Of Amperometric Glucose Biosensor, Sheng Wang, Ying Lei, Kang Shi

Journal of Electrochemistry

Electrochemically induced free radical polymerization of methacrylic acid was preliminarily investigated. Based on the electrochemical reduction of persulfate anion in phosphate buffer (pH 7.0) solution,the free radical polymerization of methacrylic acid was initiated to generate an ultrathin and biocompatible hydrogel layer on the gold electrode. At the meantime,glucose oxidase could be immobilized within the hydrogel film in the polymerization process. The resulting biosensor displayed an attractive performance.


Synthesis And Characterization For A New Organic Cathode Material Of Lithium-Ion Batteries——Poly Sulfurized Chloranilic Acid(Psca), Kai Liu, Jian-Ming Zheng, Gui-Ming Zhong, Yong Yang Aug 2009

Synthesis And Characterization For A New Organic Cathode Material Of Lithium-Ion Batteries——Poly Sulfurized Chloranilic Acid(Psca), Kai Liu, Jian-Ming Zheng, Gui-Ming Zhong, Yong Yang

Journal of Electrochemistry

A new organic cathode material,poly sulfurized chloranilic acid(PSCA),has been successfully synthesized for lithium-ion batteries. 13C solid state NMR and FTIR results indicated that the chorine in chronailic acid was substituted by sulfur after sulfurization. The electrochemical measurements showed that the initial discharge capacity of PSCA was up to 287.6 mAh/g,and 169.9 mAh/g still remained after 100 cycles when cycled between 1.5~3.6 V at the current density of 15 mA/g.


Crystallization And Electrochemical Corrosion Behaviors Of Amorphous And Nanocrystalline Fe-Based Alloys, Xiang Li, Biao Yan, Peng Dong Aug 2009

Crystallization And Electrochemical Corrosion Behaviors Of Amorphous And Nanocrystalline Fe-Based Alloys, Xiang Li, Biao Yan, Peng Dong

Journal of Electrochemistry

In this study,amorphous Fe78Si13B9 and Fe73.5Si13.5B9Nb3Cu1 ribbons were prepared by the chill block melt-spinning process and nanocrystalline Fe73.5Si13.5B9Nb3Cu1 ribbons were obtained by annealing. The amorphous ribbons and their crystallization processes were identified by differential scanning calorimeter (DSC) and X-ray diffraction (XRD). A comparative study of the electrochemical corrosion behaviors of Fe78Si13B9 and Fe73.5Si13.5B9Nb3Cu1 amorphous and nanocrystallized alloys was performed by linear polarization method and electrochemical impedance spectroscopy (EIS) in 1mol/L NaOH solutions. The photographs of the samples after potentiodynamic polarization were observed by SEM. The influence of heat treatment on the alloys structure and corrosion resistance in 1mol/L NaOH solutions …


Capacitor Property Of Pani/Mwcnt Electrode In Li_2so_4 Solution, Wen-Bo Cong, Xiao-Shu He Aug 2009

Capacitor Property Of Pani/Mwcnt Electrode In Li_2so_4 Solution, Wen-Bo Cong, Xiao-Shu He

Journal of Electrochemistry

Polyaniline/multi-walled carbon nanotubes (PANI/MWCNT) composites synthesized by chemical oxidation method were characterized by scanning electron microscopy (SEM),X-ray diffraction (XRD) and IR techniques. In 1mol/L Li2SO4 neutral solution,the electrochemical performance of the composites electrode was investigated by cyclic voltammetry,galvanostatic charge-discharge tests and ac impedance spectroscopy. The results showed that the composites electrode performed well in 1mol/L Li2SO4 solution,the specific capacitance reached 412F/g at 5 mA/cm2. The composites electrode possessed better capability of high current than that of PANI electrode,the specific capacitance kept at 318 F/g at 50mA/cm2 and was 77.2% of that at 5 mA/cm2,but the specific capacitance of PANI at …


Fabrication Of Polyvinyl Alcohol Arrays And The Direct Electrochemistry Of Adsorbed Cytochrome C, Yu-Hua Qin, Ruo-Kun Jia, Qing-Juan Wei, Li Ma, Xiao-Hui Guan, Nan Lv Aug 2009

Fabrication Of Polyvinyl Alcohol Arrays And The Direct Electrochemistry Of Adsorbed Cytochrome C, Yu-Hua Qin, Ruo-Kun Jia, Qing-Juan Wei, Li Ma, Xiao-Hui Guan, Nan Lv

Journal of Electrochemistry

Regular polyvinyl alcohol arrays were prepared with porous polystyrene films by a self-assembly method. Cyt c immobilized on PVA microlens arrays modified glassy carbon electrodes gave a pair of stable,well-defined and quasi-reversible cyclic voltammetric peaks at about 0.072 V (vs. Ag/AgCl) in 0.1 mol/L PBS buffer (pH = 6.89) solution. The effects of scan rate,pH and concentration of buffers on the electrochemical behaviors of Cyt c were studied in detail. The apparent heterogeneous electron transfer rate constant (k0) was evaluated to be 2.98×10-6 cm·s-1.