Repetitive start-up and shut-down events in polymer electrolyte membrane fuel cells for automotive applications lead to serious corrosion of the cathode due to an instantaneous potential jump that results from unintended air leakage into the anodic flow field followed by a parasitic oxygen reduction reaction (ORR) on the anode. Here we report a solution to the cathode corrosion issue during the start-up/shut-down events whereby intelligent catalyst design is used to selectively promote the hydrogen oxidation reaction (HOR) while concomitantly suppressing the ORR on the anode. Platinum thin layers supported on hydrogen tungsten bronze (Pt/H_xWO₃) suppressed the ORR by converting themselves into an insulator following exposure to oxygen, while selectively promoting the HOR by regaining metallic conductivity following subsequent exposure to hydrogen. The HOR-selective electrocatalysis imparted by a metal–insulator transition in Pt/H_xWO₃ demonstrated a remarkably enhanced durability of membrane electrode assemblies compared to those with commercial Pt/C catalysts.

汽车应用中的聚合物电解质膜燃料电池中反复发生的启动和关闭事件会导致阴极严重腐蚀，这是由于瞬间的电位跳变所引起的，这是由于意外的空气泄漏进入阳极流场并随后发生了寄生的氧还原反应（ ORR）。在这里，我们报告了启动/关闭事件期间阴极腐蚀问题的解决方案，其中智能的催化剂设计用于选择性地促进氢氧化反应（HOR），同时抑制阳极上的ORR。氢钨青铜上支撑的铂薄层（Pt / H _x WO ₃）通过在暴露于氧气后将自身转化为绝缘体来抑制ORR，同时通过在随后暴露于氢气后恢复金属导电性来选择性地促进HOR。与商业化的Pt / C催化剂相比，Pt / H _x WO _3中金属-绝缘体跃迁所赋予的HOR选择性电催化性能显着提高了膜电极组件的耐久性。