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Chemical Engineering

2001

Journal of Electrochemistry

Articles 1 - 13 of 13

Full-Text Articles in Engineering

Research Progress On Proton Exchange Membranes Of Fuel Cells, Jing-Rong Yu, Dan-Min Xing, Fu-Qiang Liu, Jian-Guo Liu, Bao-Lian Yi Nov 2001

Research Progress On Proton Exchange Membranes Of Fuel Cells, Jing-Rong Yu, Dan-Min Xing, Fu-Qiang Liu, Jian-Guo Liu, Bao-Lian Yi

Journal of Electrochemistry

The proton exchange membrane fuel cells(PEMFC) use proton exchange membranes(PEM) as their electrolytes. The performance of the PEMFC is strongly dependent on the characteristics of the PEM. In this paper, the requirements of the PEM utilized in the PEMFC were analyzed. The per_fluorinated, partially fluorinated and non_fluorinated PEM were introduced respectively. The structures, preparation, properties of the various types of PEM and their applications in the PEMFC were also discussed in detail.

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The Influence Of Synthesis Conditions On The Electrochemical Properties Of Spinel Limn_2o_4, Jun Feng Xu, Zhi Yu Jiang Nov 2001

The Influence Of Synthesis Conditions On The Electrochemical Properties Of Spinel Limn_2o_4, Jun Feng Xu, Zhi Yu Jiang

Journal of Electrochemistry

The electrochemical properties of spine LiMn 2O 4 synthesized via a solid state reaction were investigated. Electrolysis MnO 2(EMD), Li 2CO 3,LiOH and LiNO 3 were used as the initial materials. It was found that the electrochemical properties of LiMn 2O 4 were strongly influenced by the synthesis conditions. The LiMn 2O 4 samples prepared via the reaction of EMD and LiNO 3 showed the best properties for a lithium ion intercalation reaction. The procedure includes two steps: pretreatment at 280 ℃ for 6 hours to initiate the permeation of melting LiNO 3 into the micropores of EMD particles, followed …

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Adsorption And Oxidation Of Methanol On Pt And Sb, S Modified Pt Electrodes Using Cyclic Voltammetry And Eqcm, Guo-Liang Chen, Sheng-Pei Chen, Heng Lin, Xing-Hong Zheng, Shi-Gang Sun Nov 2001

Adsorption And Oxidation Of Methanol On Pt And Sb, S Modified Pt Electrodes Using Cyclic Voltammetry And Eqcm, Guo-Liang Chen, Sheng-Pei Chen, Heng Lin, Xing-Hong Zheng, Shi-Gang Sun

Journal of Electrochemistry

The processes of adsorption and oxidation of methanol on Pt, Pt/Sb ad and Pt/S ad electrodes were studied by using cyclic voltammetry and electrochemical quartz crystal microba_lance (EQCM). The results demonstrated that the oxidation of methanol depends strongly on oxidation states of electrode surface. Sb adatoms on Pt surface can adsorb oxygen at relatively low potentials, and exhibit catalytic effects for methanol oxidation. In contrast to Pt electrodes, the oxidation peak potential of methanol in this case negatively shifted to about 130 mV. In a contrary, the oxidation of S adatoms consumes oxygen species of Pt electrode surface. As a …

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Electrosynthesis Of A New Electroactive Poly(2,2'-Diaminophenyloxydisulfide), Yu Zhi Su, Yan Wen Rao, Ye Yang, Mei-Bing Chen, Yin Ling Qiu, Yong-Hua Zhang, Ke Cheng Gong Nov 2001

Electrosynthesis Of A New Electroactive Poly(2,2'-Diaminophenyloxydisulfide), Yu Zhi Su, Yan Wen Rao, Ye Yang, Mei-Bing Chen, Yin Ling Qiu, Yong-Hua Zhang, Ke Cheng Gong

Journal of Electrochemistry

A new electroactive poly(2,2' diaminophenyloxydisulfide) (PDAPD) was successfully synthesized from acetonitrile(AN)/tetrahydrofuran(THF)solutions containing the supporting electrolyte(LiClO 4)and the various kinds of acids(HCl,CF 3COOH,CCl 3COOH) on Pt electrode by consecutive cyclic voltammiry. The effects of the concentrations of supporting electrolyte(LiClO 4) and acid(HCl,CF 3COOH,CCl 3COOH) on electrodepositon of PDAPD film were investigated. The best experimental conditions for electrosynthesis of a highly electroactive conducting polymer film are that the concentrations are 0.1 mol/L and between 0.05 mol/L～0.5 mol/L,respectively for LiClO 4 and HCl.

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New Progress In Studies Of Lithium Nickel Oxide As Positive Electrode Materials Of Lithium Ion Batteris, Han-San Liu, Yong Yang, Zhong-Ru Zhang, Zu-Geng Lin May 2001

New Progress In Studies Of Lithium Nickel Oxide As Positive Electrode Materials Of Lithium Ion Batteris, Han-San Liu, Yong Yang, Zhong-Ru Zhang, Zu-Geng Lin

Journal of Electrochemistry

Lithium nickel oxide as the positive electrode of lithium ion batteries has aroused more and more interests.This paper reviews the recent reserches on synthesis and element_substitution of LiNiO 2 cathode material,and summarizes the intrinsical relationship between properties and sturcture of the material.The developments of new synthesis methods and mutil_substitution of the material are expecting to be studied in the future research.

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Performance Of Proton Exchange Membrane Fuel Cell With Co/H_2 Fuel, Hong-Mei Yu, Zhong-Jun Hou, Bao-Lian Yi, Ke-Wan Bi, Jing-Xin Zhang, Zhi-Yin Lin, Ming Han May 2001

Performance Of Proton Exchange Membrane Fuel Cell With Co/H_2 Fuel, Hong-Mei Yu, Zhong-Jun Hou, Bao-Lian Yi, Ke-Wan Bi, Jing-Xin Zhang, Zhi-Yin Lin, Ming Han

Journal of Electrochemistry

Fuel of proton exchange membrane fuel cell(PEMFC) mostly comes from reformate contains CO which will poison the fuel cell electrocatalyst.The effect of CO on the performance of PEMFC was studied in this paper.The results of the experiment show that when CO is fed in PEMFC,the cell voltage will be decreased violently,then it will become steady with some vibration.The poison will become more serious with higher CO content and weaker at higher temperature.The adsorption of CO on the electrocatalyst is reversible. The PtRu electrocatalyst is more suitable for the electrocatalysis of CO/H 2 than Pt electrocatalyst.

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Performance Of A Direct Methanol Fuel Cell, Zhao-Bin Wei, Jian-Guo Liu, Ya-Guang Jiao, Wei-Jiang Zhou, Wen-Zhen Li, Li-Kang Chen, Qin Xin, Bao-Lian Yi May 2001

Performance Of A Direct Methanol Fuel Cell, Zhao-Bin Wei, Jian-Guo Liu, Ya-Guang Jiao, Wei-Jiang Zhou, Wen-Zhen Li, Li-Kang Chen, Qin Xin, Bao-Lian Yi

Journal of Electrochemistry

A direct methanol fuel cell with 9cm 2 active area consists of Pt_Ru/C anode,Pt/C cathode and Nafion 115 membrane.The effect of operating conditions:methanol solution concentration,oxygen pressure and cell temperature on the cell performances was investigated.The results show that performance of single cell was enhanced by increasing oxygen pressure and cell temperature,and a maximum power density 75 mW/cm 2 was obtained in the range of 250_300 mA/cm 2 current density,0.2 MPa oxygen pressure,1.0 mol/L methanol concentration and 75 ℃ cell temperature.When cell operating at room temperature,a relatively low,but a stable performance of cell was also observed.

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Study Of The Oxidation Dynamics Of Ti-Zro_2 Metal-Ceramics, Wen-Chao Li, Li-Dong Teng May 2001

Study Of The Oxidation Dynamics Of Ti-Zro_2 Metal-Ceramics, Wen-Chao Li, Li-Dong Teng

Journal of Electrochemistry

The oxidation dynamics of hot pressed Ti ZrO 2 metal_ceramics with the composition of 50 vol.% Ti and 50 vol.% ZrO 2 has been studied. Thermodynamic analysis shows that Ti could react with O 2 but not with N 2 in the oxidizing process of Ti ZrO 2 composites at 0.1 MPa air. The oxidation dynamic behavior of Ti ZrO 2 composites is analogous to that of pure Ti. The activation energy for the oxygen diffusion in Ti ZrO 2 composites is higher than that in Ti solutions, for the presence of ZrO 2 restrains the oxygen diffusion in Ti …

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Synthesis Of Limn_2o_(4-Δ) Cl_Δ Cathode Material By Like-Sol-Gel Methode, Zhao Yong Chen, Yi He, Xing Quan Liu, Zhi-Jie Li, Zuo-Long Yu Feb 2001

Synthesis Of Limn_2o_(4-Δ) Cl_Δ Cathode Material By Like-Sol-Gel Methode, Zhao Yong Chen, Yi He, Xing Quan Liu, Zhi-Jie Li, Zuo-Long Yu

Journal of Electrochemistry

LiMn 2O 4 δ Cl δ was synthesized by like sol gel methode, with calculated LiOH.H 2O, Mn(No 3) 2.6H 2O and LiCl.H 2O, and made electrochemical test with these compounds as positive materials. Result demostrated that LiMn 2O 4 δ Cl δ cathode material has exellent stability and nearly no capacity loss after reaching stability.

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How Can Direct Mthanol Fuel Cell Benefit From Carbonate Media, Lin Zhuang, Yang Wang, Jun Tao Lu Feb 2001

How Can Direct Mthanol Fuel Cell Benefit From Carbonate Media, Lin Zhuang, Yang Wang, Jun Tao Lu

Journal of Electrochemistry

The kinetics of methanol oxidation and oxygen reduction in 0.5 mol/L K 2CO 3 were compared with those in 0.5 mol/L H 2SO 4. Experiments revealed that carbonate media could be more beneficial to direct methanol fuel cell(DMFC).Firstly, both electrode reactions show better performance in the carbonate than in the acid; secondly, materials other than noble metals become possible to be used as the anodic and cathodic catalysts;thirdly, the potential dectease caused by methanol crossover could be depressed by using metal oxide catalysts not stable in acid, such as MnO 2.

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A Study On The Performance Of Matrix Prepared By Tape Cast And Its Molten Carbonate Fuel Cells (Mcfcs), Hua-Xin Lin, Bao Lian Yi, Li Zhou, Chang-Qing He, Lian Ying Kong, En Jun Zhang Feb 2001

A Study On The Performance Of Matrix Prepared By Tape Cast And Its Molten Carbonate Fuel Cells (Mcfcs), Hua-Xin Lin, Bao Lian Yi, Li Zhou, Chang-Qing He, Lian Ying Kong, En Jun Zhang

Journal of Electrochemistry

The matrix prepared with γ LiAlO 2 powder and by tape cast displayed higher ability of preventing from gas cross over and lower ohmic polarization. The voltages of the stack (three cells,122 cm 2) stacked with the matrix were 2.02 and 1.78 V at 200 and 246 mA/cm 2, respectively, and the output power reached 53.4 W. The cell(28 cm 2) voltages were 0.85 and 0.75 V at 200 and 300 mA/cm 2, respectively,and the output power was about 6.6 W. Compensating the shrinkage of matrix in stacking cells promoted the enhancement of the MCFC performance.

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Adsorption And Oxidation Of Ethanol On Nm-Pt/Gc Electrode Ii. Eqcm And In-Situ Ftir Spectroscopic Studies In Acid Media, Guo Liang Chen Feb 2001

Adsorption And Oxidation Of Ethanol On Nm-Pt/Gc Electrode Ii. Eqcm And In-Situ Ftir Spectroscopic Studies In Acid Media, Guo Liang Chen

Journal of Electrochemistry

The adsorption and oxidation of ethanol on nm?Pt/GC electrode in acid solutions containing 0.1 mol·L -1 H 2SO 4 +0.1 mol·L -1 CH 3CH 2OH was investigated by using cyclic voltammetry , EQCM and in?situ FTIR spectroscopy. The experimental results demonstrated that the oxidation of CH 3CH 2OH is closely relaed to solution acidity and oxygen species on electrode surface; CH 3CH 2OH was oxidized on nm?Pt/GC electrode in acidic media via a dual path reaction mechanism, i.e . CH 3CH 2OH may be oxidized into CO 2 through the dissociative adsorbate (CO) and the reactive intermediates that were determined …

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The Charge Transfer Effect Of Sers Induced By The Electrochemical Hydrogen Evolution Reaction, Feng-Ming Liu, Qi Han, Yan Xia Chen, Qi Ling Zhong, Bin Ren, Zhong Qun Tian Feb 2001

The Charge Transfer Effect Of Sers Induced By The Electrochemical Hydrogen Evolution Reaction, Feng-Ming Liu, Qi Han, Yan Xia Chen, Qi Ling Zhong, Bin Ren, Zhong Qun Tian

Journal of Electrochemistry

As one of the important mechanisms of SERS, the charge transfer (CT) enhancement requires the strong interaction of the adsorbed species with the substrate in order to permit the transition of charge between the metal Fermi level (energy state) and the molecular orbital [1] . The high enhancement needs the match of the energy gap between the Fermi level (or surface state) and the orbital energy level of the adsorbed molecules with the energy of the incident light. The electrode Fermi level is usually adjusted by the applied potential to satisfy the CT resonance. For the electrochemical reaction process, the …

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