物理化学学报 >> 2009, Vol. 25 >> Issue (09): 1933-1938.doi: 10.3866/PKU.WHXB20090918

研究论文 上一篇    下一篇

乙醇在钯电极上的电氧化机理

方翔, 沈培康   

  1. 中山大学物理科学与工程技术学院, 光电材料与技术国家重点实验室, 广州 510275
  • 收稿日期:2009-03-19 修回日期:2009-06-12 发布日期:2009-09-03
  • 通讯作者: 沈培康 E-mail:stsspk@mail.sysu.edu.cn

Mechanism of Ethanol Electrooxidation on Pd Electrode

FANG Xiang, SHEN Pei-Kang   

  1. State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yat-Sen University, Guangzhou 510275, P. R. China
  • Received:2009-03-19 Revised:2009-06-12 Published:2009-09-03
  • Contact: SHEN Pei-Kang E-mail:stsspk@mail.sysu.edu.cn

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摘要：

利用循环伏安与现场傅里叶变换红外(FTIR)光谱对乙醇在Pd电极上的电氧化机理进行了研究. 循环伏安测量表明, 乙醇在Pd上氧化的性能受pH值与乙醇浓度的影响. 当溶液pH>11.0时, Pd对乙醇才具有催化性能, 而且乙醇在Pd上氧化的性能随着pH值和乙醇浓度的增加而提高. 现场红外光谱电化学测量结果证明, 乙醇在不同pH 溶液中的氧化反应机理和产物不同. 当溶液pH>13.0 时, 产物只有乙酸盐, 说明乙醇仅发生部分氧化, 乙醇中的C—C键没有断裂. 当溶液pH≤13.0时, 尽管乙醇在Pd电极上的氧化活性受到抑制, 却发生完全氧化而产生二氧化碳, 说明乙醇的C—C键在低碱环境中容易断裂, 最后乙醇被完全氧化. 实验中没有检测到CO, 表明该反应途径是一个非毒化过程.

关键词: 燃料电池, 钯, 乙醇电氧化, 现场傅里叶变换红外光谱电化学, 催化剂

Abstract:

The mechanism of ethanol electrooxidation on a Pd electrode was studied by cyclic voltammetry and in situ Fourier transform infrared (FTIR) spectroelectrochemistry. We found that the catalytic activity of the Pd electrode for ethanol oxidation was affected by the pH value of the solution and the concentration of ethanol. Catalytic reactions could not proceed until the solution pH>11.0. The performance for ethanol oxidation on Pd was improved with the increase in the pH value and ethanol concentration. The in situ FTIR spectroelectrochemical measurements indicated that the reaction mechanismand products depend on the pH value of the reaction solution. The main oxidation product was acetate at pH>13.0. The C—C bond cleavage of ethanol occurred as evidenced by the formation of CO2 at pH≤13.0, however, the catalytic activity for ethanol oxidation was quite low. No CO formation was detected during the oxidation of ethanol by FTIR spectroscopy, indicating the electrooxidation was a non-poisoning process.

Key words: Fuel cell, Pd, Ethanol electrooxidation, In situ FTIR spectroelectrochemistry, Catalyst