【摘要】 研究了用于直接乙醇燃料电池的自制Pt Sn/C阳极催化剂对乙醇的电催化氧化性能 .采用直流伏安法和交流阻抗法分析了电池温度和极化电位对乙醇电催化氧化性能的影响 ,比较了不同温度下甲醇和乙醇通过Nafion 117膜的扩散系数 .结果表明 ,乙醇通过Nafion 117膜的扩散系数小于甲醇的扩散系数 .伏安法测试结果表明 ,Pt Sn/C催化剂对乙醇的催化氧化活性高于商品化的Pt Ru/C催化剂 .在实验温度范围内 ,乙醇在Pt Sn/C催化剂上的初始氧化电位比在Pt Ru/C催化剂上低约0 2V ;同一电位下Pt Sn/C催化剂比Pt Ru/C催化剂的氧化电流密度高出 2 0～ 6 0mA/cm2 ,且电流密度的差值随温度的升高而增大 .交流阻抗法测试结果表明 ,Pt Sn/C催化剂对乙醇具有更高的催化活性 .在 90℃下 ,以 1mol/L的乙醇为燃料 ,氧气为氧化剂时 ,Pt Sn/C催化剂显示出良好的电池性能 ,电池最高功率密度为 4 4mW /cm2 ,而Pt Ru/C催化剂的电池最高功率密度仅为 2 7mW/cm2 .更多还原

【Abstract】 Ethanol was used as an anode fuel for polymer electrolyte fuel cells, and the electro-oxidation of ethanol on Pt-Sn/C and Pt-Ru/C was investigated by voltammetry and alternating current impedance method. The apparent diffusion coefficients of ethanol and methanol through the Nafion 117 membrane at different temperatures were compared. It was found that the apparent diffusion coefficient of ethanol was lower than that of methanol under the same condition. The temperature dependence of ethanol electro-oxidation property on Pt-Sn/C and Pt-Ru/C electrode was conducted by voltammetry method. In the temperature range of 30～90 ℃, the Pt-Sn/C showed superior electrocatalytic property comparing with Pt-Ru/C. For example, the onset potential of Pt-Sn/C electrode was approximately 0 2 V lower than that of Pt-Ru/C at the tested temperatures. At the same potential, the current density of ethanol electro-oxidation on Pt-Sn/C electrode was about 20～60 mA/cm2 higher than that on Pt-Ru/C, and the value difference increased with the increase of temperature. Impedance measurements were carried out to interpret the reaction mechanism of ethanol electro-oxidation. The result showed that Pt-Sn/C had higher catalytic activity for ethanol oxidation. In addition, the direct ethanol fuel cells with Pt-Sn/C electrode exhibited better performance, the peak power density was 44 mW/cm2, and it was only 27 mW/cm2 for single cell with Pt-Ru/C electrode using oxygen as oxidant at 90 ℃.更多还原