| 钒(Ⅳ/Ⅴ)电对在碳纸电极上的反应机理研究 |
| The Mechanism of Vanadium(Ⅳ/Ⅴ) Couple Redox Reaction at Carbon Paper Electrode |
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| 摘要: 采用循环伏安、极化曲线和交流阻抗技术研究了在0.8 mol·L-1 VOSO4+3.0 mol·L-1 H2SO4中，V(Ⅳ/Ⅴ)电对在碳纸电极上的反应机理及可能的速度控制步骤。研究结果表明：V(Ⅳ/Ⅴ)电对在碳纸电极上的反应属准可逆过程，且氧化过程包含有后置化学转化步骤，计算得到VO2+的扩散系数为4.5×10-5 cm2·s |
| 关键词: 钒液流电池 碳纸 钒(Ⅳ/Ⅴ)电对 控制步骤 |
| 基金项目: |
| Abstract: The V(Ⅳ/Ⅴ) reaction mechanism was investigated on a carbon paper(CP) electrode by means of cyclic voltammetry, polarization curve and impedance spectroscopies. Cyclic voltammetry analysis indicated that V(Ⅳ/Ⅴ) redox reaction at CP electrode was quasi-reversible. A certain chemical reaction step was suspected to follow the electron transfer step of this reaction. The diffusion coefficient for V(Ⅳ) was 4.5×10-5cm2·s-1 and exchange current density was 6.7×10-4 mA·cm-2. The Tafel slope value(0.127) obtained from the polarization curve agrees well with theoretical value(0.12) when the electron transfer step was supposed to be the rate-determining step. Impedance spectroscopies at various potentials were studied and simulated by equivalent circuits. The impedance value of the electron transfer step modified was greatly higher than that of the others, which revealed that the electron transfer step was the rate-determining step. This further confirms the conclusion obtained by polarization curve test. |
| Keywords: vanadium redox battery carbon paper V(Ⅳ/Ⅴ) couple determining step |
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| 刘素琴,史小虎,黄可龙,李晓刚,李亚娟,吴雄伟.钒(Ⅳ/Ⅴ)电对在碳纸电极上的反应机理研究[J].无机化学学报,2009,25(3):417-421. |
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