Ion-Etching-Induced Defect Engineering toward Porous Fe-N-C Catalysts for Efficient Oxygen Reduction Reaction

Abstract

Fe-N-C catalysts are considered as the most promising candidates to replace Pt-based materials for the oxygen reduction reaction (ORR) in energy conversion devices. Defect engineering is a facile and effective strategy to boost ORR activity; however, the precise construction of defects remains challenging. Here, the ion-etching method was employed to create ZIF-derived defects-rich porous nitrogen-doped carbon (pNC) anchored Fe sites (denoted as d-Fe-N-C) as efficient electrocatalyst for ORR, achieving the synergistic optimization of mass transport and intrinsic activity. The catalyst d-Fe-N-C exhibited excellent ORR activity, with a half-wave potential (E1/2) of 0.91 V vs. RHE in 0.1 M KOH, surpassing that of Pt/C (0.86 V). The zinc-air batteries (ZABs) assembled with d-Fe-N-C delivered peak power density (Pmax) of 186 mW cm -2 , superior to commercial Pt/C (127 mW cm -2 ). This work offers new insights into the rational design of Fe-N-C catalysts using ionetching-induced defect engineering to achieve high-performance for ORR.