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Full-Text Articles in Physical Sciences and Mathematics

Gold Electrodeposition On Microelectrodes, Lihua Xiong, Caihui Shi, Xiaoqin Li, Bingwei Mao Feb 1998

Gold Electrodeposition On Microelectrodes, Lihua Xiong, Caihui Shi, Xiaoqin Li, Bingwei Mao

Journal of Electrochemistry

The initial stage electrodeposition behaviors of gold onto glassy carbon and platinum microelectrodes are studied in an acid solution containing AuCl_3using cyclic voltammetry and potential step techniques. The results suggest that gold nucleation on microelectrodes requires a higher driving force with high probability. Within the range of the microelectrode dimension that have been used in the present work, large amount of gold nucleus could be formed at short time scale at overpotentials higher than a threshole value. The It curves from the platinum microelectrode are in consistence with the continuous nucleation model. It has been found that the deosition history …


Microelectrode Studies On The Pitting Corrosion Process Of Stainless Steel, Changjian Lin, Lijian Chen, Ronggui Du, Zude Feng, Jianguang Tang, Hongping Dai Feb 1998

Microelectrode Studies On The Pitting Corrosion Process Of Stainless Steel, Changjian Lin, Lijian Chen, Ronggui Du, Zude Feng, Jianguang Tang, Hongping Dai

Journal of Electrochemistry

Abstract Differing with the scanning microelectrode techniques, which scan microelctrode closely to the interface of electrode/electrolyte and make electrochemical imaging in a lateral spatial resolution, the technique of microelectrode with a micron diameter is of very high timeresolution and ratio of signal/noise in electrochemical measurements. The microelectrode technique allows doublelayer capacitance and background current for a microelectrode to be drastically reduced due to the exposed area of a microelectrode is usually 6~8 orders of magnetite lower than that of a conventional electrode with largescale exposed area. Microelectrode was recently developed as a new powerful electrochemical technique and widely used in …


Spectroscopic Investigation Of Ion Transport Mechanisms In Polyacrylonitrile Based Electrolytes, Zhaoxiang Wang, Biying Huang, Rongjian Xue, Xuejie Huang, Liquan Chen Feb 1998

Spectroscopic Investigation Of Ion Transport Mechanisms In Polyacrylonitrile Based Electrolytes, Zhaoxiang Wang, Biying Huang, Rongjian Xue, Xuejie Huang, Liquan Chen

Journal of Electrochemistry

Raman, IR, X-ray photoelectron (XPS), and NMR spectra of components in polyacrylonitrilebased electrolytes have been studied. It is found that there are strong interactions among the components though different systems show different interaction characteristics. A concept of competition is proposed between the polymer matrix and the plasticizer on associating with the Li~+ ions. By analyzing the important functions of the plasticizer, a possible mechanism of the ions transport in the polymer electrolyte is suggested.


The Investigations Of Surface Treatment Methods And Characterization Of Oxide Films On Ab_5Based Metal Hydride Electrodes Ⅰ. New NiRich Treatment Methods And Photoelectrochemical Characterization Of Oxide Films, Junmin Nan, Yong Yang, Jun Li, Zugeng Lin Feb 1998

The Investigations Of Surface Treatment Methods And Characterization Of Oxide Films On Ab_5Based Metal Hydride Electrodes Ⅰ. New NiRich Treatment Methods And Photoelectrochemical Characterization Of Oxide Films, Junmin Nan, Yong Yang, Jun Li, Zugeng Lin

Journal of Electrochemistry

Two simple and efficient surface treatment methods for AB_5type hydrogen storage alloys were developed. The results of X-ray photoelectron spectroscopy (XPS) and cyclic voltammetric (CV) experiments showed that the hydrogen storage alloys treated by two different methods had Nirich surface layer so that the performances of the electrodes were improved after treatment. The characterization of the oxide films which formed on the surface of electrodes through potentiodynamic oxidation with the help of photoelectrochemical microscopy (PEM) were done. The anodic photocurrent and the cathodic photocurrent related to the oxidation of hydrogen and the reduction of oxygen on the surface layer were …


Investigation On The Ellipsometry For The Detection Of Nickel Through Anodic Stripping Voltammetry, Wei Zhu, Yuru Yang, Zongqing Huang Feb 1998

Investigation On The Ellipsometry For The Detection Of Nickel Through Anodic Stripping Voltammetry, Wei Zhu, Yuru Yang, Zongqing Huang

Journal of Electrochemistry

The ellipsometry with a new parameter Vop  and anodic stripping voltammetry are used to analyze the nickel ions solutions with different concentration of 10-6~10-9 mol/L. It is shown that the results given by both methods are identical and the sensitivity and accuracy of ellipsometry are higher than anodic stripping voltammety.


The Migration Of Samarium(Ⅲ)Across Oil/Water Interface, Junwei Di, Xiaoxing Xu, Ying Wu, Ruixi Fan Feb 1998

The Migration Of Samarium(Ⅲ)Across Oil/Water Interface, Junwei Di, Xiaoxing Xu, Ying Wu, Ruixi Fan

Journal of Electrochemistry

The migration of Samarium(Ⅲ)across water/nitrobenzene (w/nb) interface facilitated by diantipyrylmethane (DAM) and the electrochemical behaviour affected by emulsifier OP in the nb phase have been studied by normal and convolute cyclic voltammetry. It is concluded that the formation of the complex occurs at w/nb interface and the mechanism of the samarium(Ⅲ)transfer across w/nb interface facilitated by DAM is E mechanism.


Anchor Effect Of Iron And Cobalt To Platinum On Carbon Substrates, Zidong Wei Feb 1998

Anchor Effect Of Iron And Cobalt To Platinum On Carbon Substrates, Zidong Wei

Journal of Electrochemistry

The cathodic reduction of oxygen is studied on porous carbonbased electrodes carrying platinumiron and/or cobalt alloy catalysts. Electrodes using such electrocatalysts, particularly when used as cathodes in acidic electrolytes, remain stable for longer periods. The cathodic polarization of oxygen reduction on such electrodes is 20 mV to 40 mV lower than that on the conventional electrode on which only platinum alone is used as an electrocatalysts. An accelerated aging test (AAT) is used to evaluate the corrosion resistance and sintering resistance of each catalyst. The dissolution of the catalyst in the AAT filtrate is analysed and provides a measure of …


The Time Dependent Red Shift Phenomenon Of Visible Electroluminescence Of Porous Silicon, Rongqiu Wang, Jingjian Li, Shengmin Cai, Zhongfan Liu Feb 1998

The Time Dependent Red Shift Phenomenon Of Visible Electroluminescence Of Porous Silicon, Rongqiu Wang, Jingjian Li, Shengmin Cai, Zhongfan Liu

Journal of Electrochemistry

The electroluminescence (EL) of ntype porous silicon (PS) in a persulphate solution under cathodic polarization was studied. A significant red shift in the luminescence spectra with the increase of polarization time, as well as a blue shift with the increase of cathodic polarization, have been found. FTIR, MicroRaman, AFM and photoelectrochemical techniques have been used to investigate the structure of PS before and after the electroluminescence emission. All these results show that the surface of PS has been oxidized by the persulphate during the EL emission, and accompanied by the stripping of small silicon nanocrystallite, which leades to the red …


Electrochemical Impedance Of Molten Salts Induced Hot Corrosion, Chaoliu Zeng, Weitao Wu, Jianqing Zhang Feb 1998

Electrochemical Impedance Of Molten Salts Induced Hot Corrosion, Chaoliu Zeng, Weitao Wu, Jianqing Zhang

Journal of Electrochemistry

Electrochemical impedance technique was employed to study corrosion behaviors of Ni-3Al, IN100 and IN738 alloys in molten (Na, K, Li)_2SO_4 at 700 ℃. The Nyquist plots for Ni-3Al and IN100 alloys have the characteristics of diffusioncontrolled reaction. But, the corrosion reaction for IN738 alloy is not controlled by the diffusion of oxidants. The equivalent circuits were proposed, and the parameters in circuits were also calculated. Ni-3Al and IN100 alloys suffer from catastrophic corrosion due to the formation of a porous corrosion layer. IN738 alloy has excellent corrosion resistance because of the formation of a protective oxide scale.


Study On The Synthesis And Electrochemical Behavior Of Poly (QuinonoidDisulfide), Xiaohui Tang, Xiuwu Sun, Yongfang Li, Shibi Fang Feb 1998

Study On The Synthesis And Electrochemical Behavior Of Poly (QuinonoidDisulfide), Xiaohui Tang, Xiuwu Sun, Yongfang Li, Shibi Fang

Journal of Electrochemistry

Organic polydisulfide containing quinonoid structure was synthesized by chloromethylation, oxidation by nitric acid, and condensation polymerization with sodium disulfide. The effect of quinonoid structure on the electrochemical behavior of organic polydisulfide was investigated with cyclic voltammetry and chargedischarge measurement. The result shows that quinonoid struture mainly affects the positions of redox peaks of organic polydisulfide, open circuit voltage and discharge platform voltage of cell with the organic polydisulfide as cathode.


Progress In Intersection Of Modern Electrochemisity And Materials Science, Changjian Lin Feb 1998

Progress In Intersection Of Modern Electrochemisity And Materials Science, Changjian Lin

Journal of Electrochemistry

A brief introduction to the Joint Conference of Electrochemistry of the 48th  Annual Meeting of International Society of Electrochemistry and the 192nd Electrochemistry Society was presented. The progress in intersection of modern electrochemistry and materials science was emphasized in the review.


Progresses In Surface Electrochemistry And Electrocatalysis ——A Review On The 1997 Joint International Meeting Of Electrochemistry And 97′ International Meeting Of Surface Electrochemistry, Shigang Sun Feb 1998

Progresses In Surface Electrochemistry And Electrocatalysis ——A Review On The 1997 Joint International Meeting Of Electrochemistry And 97′ International Meeting Of Surface Electrochemistry, Shigang Sun

Journal of Electrochemistry

The progresses in surface electrochemistry and electrocatalsis reported in the 1997 joint international meeting of electrochemistry and in the 97′ international meeting of surface electrochemistry were reviewed. The main trends described in this paper consisted of 7 aspects: 1) the studies employing single crystal electrodes, 2) the development of in situ methods of diverse spectroscpoy, 3) the innovation of new research techniques, 4) the preparaton of electrocatalyst of high performances, 5) the quantitative studies on kinetics of electrocatalytic reactions, 6) the investigation on the dynamic processes of surface by timeresolved methods, and 7) the theoretical modeling and simulation of surface …


Preparation Of High Rate Discharge Foamed Nicd Battery, Yuming Wang Nov 1997

Preparation Of High Rate Discharge Foamed Nicd Battery, Yuming Wang

Journal of Electrochemistry

A novel device of SC type foamed NiCd battery is presented, in which, the innerresistance of battery is appeared to be reduced, and the electrode performance is gained to very improved, and so, this battery can be suited to using of the powerdrive pistol drill.


Development Of A New Type Ni-S Evolution Hydrogen Electrode For Water Electrolysis, Xiaoyou Yuan Nov 1997

Development Of A New Type Ni-S Evolution Hydrogen Electrode For Water Electrolysis, Xiaoyou Yuan

Journal of Electrochemistry

A new type evolution hydrogen electrode NiS(N) has been made from nickel plating electrode in NiSO4CS(NH2)2 bath by electrodeposition. It is analyzed by SEM and Xray energy spectrum. The NiS(N) electrode is different from the NiS(O) electrode (which is used in plant at present time) in surface metallograph configuration and surfer content. The results of measurement polarization curves and water electrolysis 480 hours at 5 000 A·m-2 show that the evolution hydrogen overpotential of NiS(N) electrode is decreased at least 160 mV relative to NiS(O) electrode and the stablisum of NiS(N) electrode is better than that of NiS(O) electrode.


Advances In Solid Polymer Electrolytes, Liming Ding, Shaojun Dong, Erkang Wang Nov 1997

Advances In Solid Polymer Electrolytes, Liming Ding, Shaojun Dong, Erkang Wang

Journal of Electrochemistry

The formation, classification, applications and iontransport mechanism studies of solid polymer electrolytes were reviewed. While the recent SPE reports on the preparation of novel materials, the full structure determinations of PEO/salt complexes, the exploration of iontransport mechanism and the applications in electrochemical devices being introduced, some prospects on the future SPE research were suggested. 84 references were quoted.


Calculation Of The Sacrificial Anode Resistance Utilizing Boundary Element Method, Jianhua Wu, Mingxian Sun, Guangzhou Liu, Guangzhang Chen Nov 1997

Calculation Of The Sacrificial Anode Resistance Utilizing Boundary Element Method, Jianhua Wu, Mingxian Sun, Guangzhou Liu, Guangzhang Chen

Journal of Electrochemistry

According to a kind of mathematic model set up for the cathodic protection potential field, the boundary element method (BEM) was used to study the working state of plate sacrificial anodes which were galvanically coupled to mild steel. In situ experiment showed that the current output and resistance of sacrificial anodes could be calculated more accurately using BEM than loiyd formula. On the basis of the calculation, the cathodic protection design would be more accurate. It was also investigated that the effect of the lengthtobreadth ratio (L/B) on current output and resistance of plate zinc anodes. The results demonstrated that …


Cyclic Voltammetric Investigation Of The Axial Coordination Effects Of Pyridine On The Redox Behaviours Of (Tpp)Co, Chuanwei Yan, Xiangqui Lin, Haichao Lin, Chunan Cao Nov 1997

Cyclic Voltammetric Investigation Of The Axial Coordination Effects Of Pyridine On The Redox Behaviours Of (Tpp)Co, Chuanwei Yan, Xiangqui Lin, Haichao Lin, Chunan Cao

Journal of Electrochemistry

The electrochemistry of (TPP)Co in presence of pyridine was investigated in dichloroethane solution by cyclic voltammetry. Upon the addition of pyridine to the solution, two reduction peaks of Co(Ⅲ)/Co(Ⅱ) at 0.25 and -0.40 V (SCE) were observed. It was infered that the peaks were belong to the reductions of the complex compounds with one and two axial pyridine, (TPP)Co(Ⅲ)(Py) and (TPP)Co(Ⅲ)(Py)2. Even though the mole ratio of added pyridine was less than 1 the reduction of Co(Ⅲ)/Co(Ⅱ) still mainly occured at -0.40 V, which evidently resulted from pyridine adsorption on the electrodes. Besides, it was observed that the reduction peak …


Mechanism Of Electrodeposition Of Cu/Co Multilayer Thin Films, Jiangyun Xue, Jixun Wu, Dejun Yang Nov 1997

Mechanism Of Electrodeposition Of Cu/Co Multilayer Thin Films, Jiangyun Xue, Jixun Wu, Dejun Yang

Journal of Electrochemistry

The mechanism of electrodeposition of Cu/Co multilayer thin films has been studied by means of potentodynamic sweep, cyclic voltammetry sweep and AC impendance. The results indicated that the copper deposition is mass transfer controlled process and the cobalt deposition is related to the absorbed intermediate species such as Co(OH)ads. The cobalt ions first form Co(OH)ads, then was deoxygenated to cobalt on the electrode surface.


Study On The Electrochemical Behaviour Of Eu(Ⅲ) Tryptophane Imidazole Triple Complex, Huixia Wu, Zemin Wang, Xiaqin Wu, Haifeng Yang, Zongrang Zhand Nov 1997

Study On The Electrochemical Behaviour Of Eu(Ⅲ) Tryptophane Imidazole Triple Complex, Huixia Wu, Zemin Wang, Xiaqin Wu, Haifeng Yang, Zongrang Zhand

Journal of Electrochemistry

Eu(Ⅲ)TryptophaneImidazole binary and triple complexes were synthesized. IR spectra indicate that the carboxy group of tryptophane and the N atom of imidazole are coordinated with Eu(Ⅲ) ion. Cyclic voltammetry was used to study the electrochemical behaviour of Eu(Ⅲ) ion, the mixture of Eu(Ⅲ) with tryptophane and imidazole, and Eu(Ⅲ) binary or triple complexes. Among the scan range of -0.4~-1.0 V (vs. SCE), all of these three kinds of systems depicted pseudoreversible electron transfer. The kinetic parameters including D and Ks were also evaluated. 


Study On Perchlorate Produced By Electrolysis With Oxygen Cathode, Zhigang Shao, Baolian Yi, Naichao Li, Ming Han Nov 1997

Study On Perchlorate Produced By Electrolysis With Oxygen Cathode, Zhigang Shao, Baolian Yi, Naichao Li, Ming Han

Journal of Electrochemistry

A new method of measuring the flow capacity of cell gas in the perchlorate cell process equipped with an oxygen cathode is applided to investigate the influence of changes in the concentration of solution (chloride, chlorate, perchlorate and metal ion) and changes in the operation parameters (current density, temperature and pH) on perchlorate current efficiency. The main abstacle that the oxygen cathode is used in the perchlorate cell process is put forward and a method is provided to resolve it.


The Effect Of Solution Composition On The Corrosion Behavior Of Electrodeposited Zinc Powder, Qingwen Li, Qin Yang, Xi Xia Nov 1997

The Effect Of Solution Composition On The Corrosion Behavior Of Electrodeposited Zinc Powder, Qingwen Li, Qin Yang, Xi Xia

Journal of Electrochemistry

Zinc powder as a widely anode material can be electrowon from ZnCl2 or ZnO+KOH media. The properties of zinc powder are likely to be modified with electrolytic conditions such as the composition of bath solution, electrolysis manner, current density and additives etc.. In this paper, we have discussed the effect of the compositions of bath solution on the microstructure and corrosion resistance of zinc powder.


The Initial Process Of Amophous Electroless Nickel, Yi Chi, Lei Zhang, Yijan Wang, Maoyuan Ma Nov 1997

The Initial Process Of Amophous Electroless Nickel, Yi Chi, Lei Zhang, Yijan Wang, Maoyuan Ma

Journal of Electrochemistry

The initial process and mophology of electroless nickel played a domination role in adhesive strenghth of EN coating. The structure of initial deposits on certain matrixes was observed by TEM analysis. The deposition of a extremaly fine grain film depended on relative contrast between a coating and a matrix in crystal lattice parameters. When the coating and matrix had similar srystal lattice parameters. A extremely fine grain film was obtained. On the contrary, when the crystal lattice parameters were very different, a amorphous structure was observed.


The Activity Of Alloy CuNi Electrode In Electroreduction Of Aromatic NitroCompounds, Chunan Ma, Shaoping Tong, Xiaojun Cheng, Hui Wang Nov 1997

The Activity Of Alloy CuNi Electrode In Electroreduction Of Aromatic NitroCompounds, Chunan Ma, Shaoping Tong, Xiaojun Cheng, Hui Wang

Journal of Electrochemistry

CuNi alloy on the basis of copper at different ratio Cu/Ni are prepared by codepostion. The cathode activtiy of film are studied by steadystate polarization for electroreduction nitrobenzene (NB) and 1,5dinitroanthraquinone (1,5DNA) to paminophenol and 1,5diamino4,8dihydroanthraquinone respectly. The results show that the alloy cathodes at different ratio Cu/Ni have different exchange current density (io) and apparent activition energy (EA). The alloy (CN30) has maximal io  and minimal EA by codeposition at the following conditions: electrolyte: 0.05 mol/L CuSO4·5H2O+0.6 mol/L NiSO4·6H2O+0.25 mol/L Na3Cit·2H2O; current density: 0.6 A/dm2 , pH=6, temperature at 50 ℃. Compared with the common cathodes such as …


Study On The Oxygen Electrodes Of Alkaline Fuel Cells Effect Of Dopant On The Activity Of Ag/C Catalyst, Jiawei Teng Nov 1997

Study On The Oxygen Electrodes Of Alkaline Fuel Cells Effect Of Dopant On The Activity Of Ag/C Catalyst, Jiawei Teng

Journal of Electrochemistry

A new kind of nonnoble catalyst for the oxygen electrodes of Alkaline Fuel Cells was investigated. The AgNiBiHg/C catalyst, which was prepared by chemical reduction, was active for the cathodic reduction of oxygen in alkaline fuel cells. It was found that the catalytic activity was improved by adding Ni, Bi, Hg to Ag/C catalyst, and the maximum activity was observed at Ag50%Ni2%Bi3%Hg3%C42%(wt%). XRD inconjunction with SEM indicated that the crystalline silver turned into amorphous in the presence of doping agents and the grain size of silver was reduced. No dramatic deactivation of the catalyst occured after 5200 hours of service.


Molten Carbonate Fuel Cell Materials And Technology, Naichao Li, Baolian Yi Nov 1997

Molten Carbonate Fuel Cell Materials And Technology, Naichao Li, Baolian Yi

Journal of Electrochemistry

Molten Carbonate Fuel Cell materials are reviewed, and the technology of Molten Carbonate Fuel Cell are discussed.


Effect Of Addition Groups On The Redox Properties Of Fullerenes, Louzhen Fan, Yongfang Li, Dagui Li Yuliang Zheng, Daoben Zhu Nov 1997

Effect Of Addition Groups On The Redox Properties Of Fullerenes, Louzhen Fan, Yongfang Li, Dagui Li Yuliang Zheng, Daoben Zhu

Journal of Electrochemistry

Electrochemical properties of fullerene derivatives, including five C60 derivatives and four C70 derivatives, were studied systematically and comparatively by cyclic voltammetry and differential pulse wave voltammetry. The addition of the electrondonating groups on the fullerenes caused negative shift of the redox potentials of the fullerenes. The extent of the negative shift depends on the number and properties of the addition groups, and on the nature of the fullerenes. 0.08~0.20 V negative shift was observed for C60 and C70 monoadducts, 0.30~0.32 V for bisadduct and 0.53~0.58 V for triadduct of C60. Meanwhile, the oxidation waves of most of these derivatives appeared …


Li/Α-Sn(Hpo4)2 Cell And Its Reaction Mechanism, Yuan Lin, Runliang Cai, Haoqing Wu Nov 1997

Li/Α-Sn(Hpo4)2 Cell And Its Reaction Mechanism, Yuan Lin, Runliang Cai, Haoqing Wu

Journal of Electrochemistry

The discharge mechanism of Li/αSn(HPO4)2 cell has been investigated by means of Xray diffraction, XPS and cyclic voltammetry methodes. It has been shown that the electrochemical intercalation reation exists in the cathode material. There is a new phase after some degree of intercalation. With potential step and galvanostatic techniques, the chemical diffusion cofficients of Li+ in LixSn(HPO4)2 is estimated to be 10-12~10-13 cm2·s-1.


The Effect Of Bismuth On Microstructure Of The Cathodic Copper Deposition Of Copper Electrorefining, Daorong Lu, Jianxing Lin Nov 1997

The Effect Of Bismuth On Microstructure Of The Cathodic Copper Deposition Of Copper Electrorefining, Daorong Lu, Jianxing Lin

Journal of Electrochemistry

The electrocrystal formation, crystal orientation and the chemical composition of the cathodic copper deposition in the presence of Bi3+ in the electrolyte of acidified CuSO4 are studies by scanning electron microscopy, Xray diffraction, atomic absorption and EDAM. The results indicate that the Bi could′t deposit on cathode when copper electrolysed at common current density i=200 A·mol/L-2 and t=60 ℃. Bi3+ scarcely effected on the crystal orientation (220) of copper deposition. High concentration Bi3+ in the electrolyte promoted (220) growth and inhibited the other crystal orientation growth. Bi3+ effected on electrocrystal formation and the cell dimension of copper deposition.


Photoluminescence Of Photoelectrochemically Etched N+-Si, Guozheng Li, Chengqian Zhang, Xiumei Yang Nov 1997

Photoluminescence Of Photoelectrochemically Etched N+-Si, Guozheng Li, Chengqian Zhang, Xiumei Yang

Journal of Electrochemistry

PS layer on n+Si with (111) orientation prepered by means of photoelectrochemically etched has photoluminescent (PL) ability like PS layer on usual nSi. The data of PL spectra and quenching are given.


Electrical Potential Distribution Around A Charged Colloidal Particle: Nonlinear Integral Equation, Yongxian Qian Aug 1997

Electrical Potential Distribution Around A Charged Colloidal Particle: Nonlinear Integral Equation, Yongxian Qian

Journal of Electrochemistry

The electrical potential distribution around a charged colloidal particle in a solution of general electrolytes is governed by the nonlinear Poisson Boltzmann equation, which is a differential equation and difficult to solve analytically. In this paper we numerically calculate the electrical potential using nonlinear Qian Poisson Bolazmann integral equation (PBIE). First, we introduce the PBIE derived from the physical principles for electrostatic fields and thermodynamic systems. Then the PBIE is numerically solved by means of iteration, in which the discrete potential is solely used. Finally, the accuracy of the numerical solutions proposed here is discussed. The potentials for the colloidal …