Operational Performance Recovery of SO2-Contaminated Proton Exchange Membrane Fuel Cells
Operational Performance Recovery of SO2-Contaminated Proton Exchange Membrane Fuel Cells
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DOI：
10.1149/1.3483108
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发表时间：
2010-11
影响因子：
3.9
通讯作者：
Benjamin D. Gould;G. Bender;K. Bethune;S. Dorn;O. Baturina;R. Rocheleau;K. Swider-Lyons
中科院分区：
文献类型：
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作者：
Benjamin D. Gould;G. Bender;K. Bethune;S. Dorn;O. Baturina;R. Rocheleau;K. Swider-Lyons
空气中的硫污染物（so2、h2s和COS）会吸附在Pt催化剂上并改变反应位点以进行氧还原，从而导致质子交换膜燃料电池（pemfc）的性能下降。电化学方法可以将Pt催化剂上吸附的硫化物（sox）在高电位下氧化成硫酸盐（so2 - 4），然后在低电位下作为水溶性阴离子去除，从而恢复PEMFC的性能。在60°C、48.3 kPa g （7 psi）和100 bbb50 %（阳极|阴极）的相对湿度下，暴露于1 ppm so2空气中3小时后，我们研究了五种不同方法对PEMFC性能恢复的有效性。这些方法是在Pt表面部分覆盖但不完全饱和的情况下进行测试的。这些方法包括阴极电位和气体环境（氮气或空气）的变化。在最佳方法中，通过电化学消耗空气中的o2，将电池从正常的h2|空气操作切换到h2|n2。然后将电位在0.09到1.1 v之间与阳极电位循环，以恢复97%的铂催化剂电化学表面积。这种原位n2循环方法在不到3分钟的时间内将污染的pemfc的极化曲线恢复到其原始性能。
Airborne sulfur contaminants (SO 2 , H 2 S, and COS) cause the performance of proton exchange membrane fuel cells (PEMFCs) to degrade because they adsorb to the Pt catalysts and modify reaction sites for oxygen reduction. Electrochemical methods can be used for PEMFC performance recovery by oxidizing adsorbed sulfur species (SO x ) on the Pt catalysts to sulfate (SO 2- 4 ) at high potentials and then removing them as water-soluble anions at low potentials. We examine the effectiveness of five distinct methods for PEMFC performance recovery after 3 h of exposure to 1 ppm SO 2 in air at 60°C and 48.3 kPa g (7 psi) and relative humidity of 100 | 50% (anode | cathode). The methods are tested when the Pt surface is partially covered but not completely saturated with sulfur species. The methods include variations in the cathode potential and gas environment (N 2 or air). In the optimum method, the cells are switched from normal H 2 | air operation to H 2 | N 2 by electrochemically consuming O 2 in the air. The potential is then cycled between 0.09 and 1.1 V. vs the potential at the anode to restore 97% of the platinum catalyst electrochemical surface area. This in situ N 2 cycling method returns the polarization curves of contaminated PEMFCs to their original performance in less than 3 min.