Impact of Sulfur Dioxide on the Oxygen Reduction Reaction at Pt/Vulcan Carbon Electrocatalysts
Impact of Sulfur Dioxide on the Oxygen Reduction Reaction at Pt/Vulcan Carbon Electrocatalysts
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DOI：
10.1149/1.2736648
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发表时间：
2007-07
影响因子：
3.9
通讯作者：
Y. Garsany;O. Baturina;K. Swider-Lyons
中科院分区：
文献类型：
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作者：
Y. Garsany;O. Baturina;K. Swider-Lyons
采用旋转环盘电极法对铂燃料电池材料中吸附含硫物质的氧还原反应（ORR）进行了定量研究。研究了硫化碳（Pt/VC）上Pt电极浸没在so2溶液中的污染。Pt的初始硫覆盖率由硫在0.05 V（相对可逆氢电极）下从S°氧化到>1.3 V下的水溶性硫酸盐（so2 - 4）所消耗的总电荷来确定。然后评估电极的ORR活性。当约1.2%的铂表面吸附含硫物质时，测量到铂质量活性的显著损失（33%）。14%的硫覆盖率导致95%的质量活性损失。当37%的Pt表面被硫覆盖时，ORR在Pt/VC催化剂上的反应途径由4电子变为2电子，过氧化氢是一种具有攻击性的试剂。我们得出结论，在质子交换膜燃料电池的典型稳态操作条件下，吸附的硫不会被去除，因此它会通过降低催化剂的质量活性和增加有害的h2o2副产物的形成来影响操作。
The poisoning of the oxygen-reduction reaction (ORR) by adsorbed sulfur-containing species was quantified for platinum fuel-cell materials using rotating ring disk electrode methodology. Electrodes of Pt on Vulcan carbon (Pt/VC) were contaminated by submersion in SO 2 -containing solutions. The initial sulfur coverage of the Pt was determined from the total charge consumed as the sulfur was oxidized from S° at 0.05 V (vs a reversible hydrogen electrode) to water-soluble sulfate (SO 2- 4 ) at >1.3 V. Electrodes were then evaluated for their ORR activity. Significant (33%) loss in Pt mass activity was measured when approximately 1.2% of the Pt surface had adsorbed the sulfur-containing species. Sulfur coverage of 14% caused a 95% loss in mass activity. When 37% of the Pt surface was covered with sulfur, the reaction pathway of the ORR on the Pt/VC catalyst changed from a 4-electron to 2-electron process reaction for peroxide, a reagent which can aggressively attack Nafion. We conclude that adsorbed sulfur is not removed under typical steady-state operating conditions of a proton exchange membrane fuel cell, so it will affect operation by decreasing mass activity of the catalysts and by enhancing formation of the deleterious H 2 O 2 by-product.