Na^+对PEMFC Pt/C气体扩散电极的影响

Effect of impurity Na^+ on Pt/C gas-diffusion electrode in PEMFC

采用燃料电池半电池体系模拟了质子交换膜燃料电池(PEMFC)中Na+污染气体扩散电极时的工况,研究了Na+对PEMFC常用的Pt/C气体扩散电极性能的影响。通过循环伏安曲线和电化学阻抗谱,测试了电极在Na+污染前后催化层电化学比表面积(ECA)和电极反应界面上的电荷转移电阻发生的变化。实验结果表明,随Na+污染浓度的增大,电极性能逐渐下降;污染后电极催化层电化学活性比表面积出现明显减少,当污染物浓度为10000×10-6时,ECA降低了43%;外加相同电位时,随Na+污染的增加,电极反应界面上的电荷转移电阻逐渐增大。Na+的存在对Pt/C气体扩散电极具有明显毒化作用。

By using a half fuel cell set-up to simulate the working condition of Na^＋ contamination, the effect of impurity Na^＋ on Pt/C gas-diffusion electrode which is wildly used in PEMFC was investigated. The performance of half fuel cell was seriously influenced by impurity Na^＋ contamination. By testing cyclic voltammetry and electrochemical impedance spectrum, the obvious change of the electrochemically active specific surface area of contaminated catalyst and the charge transfer resistance between reaction interfaces were detected. The results show that with the increase of Na^＋ concentration, the performance of electrode decreases gradually; the electrochemically active specific surface area of contaminated electrode shows a marked reduction, even the ECA decreases about 43% when the concentration of Na^＋ contamination reaches 10 000 × 10^-6; the charge transfer resistance between reaction interfaces increases gradually under the same potential. There is a remarkable poisoning effect of impurity Na^＋ on Pt/C gas-diffusion electrode.