Instantaneous Free Radical Scavenging by CeO<sub>2</sub> Nanoparticles Adjacent to the Fe−N<sub>4</sub> Active Sites for Durable Fuel Cells
Xiaoyang Cheng, Xiaotian Jiang, Shuhu Yin, Lifei Ji, Yani Yan, Guang Li, Rui Huang, Chongtai Wang, Hong‐Gang Liao, Yanxia Jiang, Shi‐Gang Sun
Abstract
Abstract To achieve the Fe−N−C materials with both high activity and durability in proton exchange membrane fuel cells, the attack of free radicals on Fe−N 4 sites must be overcome. Herein, we report a strategy to effectively eliminate radicals at the source to mitigate the degradation by anchoring CeO 2 nanoparticles as radicals scavengers adjacent (Sca ad‐CeO2 ) to the Fe−N 4 sites. Radicals such as ⋅OH and HO 2 ⋅ that form at Fe−N 4 sites can be instantaneously eliminated by adjacent CeO 2 , which shortens the survival time of radicals and the regional space of their damage. As a result, the CeO 2 scavengers in Fe−NC/Sca ad‐CeO2 achieved ∼80 % elimination of the radicals generated at the Fe−N 4 sites. A fuel cell prepared with the Fe−NC/Sca ad‐CeO2 showed a smaller peak power density decay after 30,000 cycles determined with US DOE PGM‐relevant AST, increasing the decay of Fe−NC Phen from 69 % to 28 % decay.