Electronic Asymmetry Engineering of Fe–N–C Electrocatalyst via Adjacent Carbon Vacancy for Boosting Oxygen Reduction Reaction

Abstract Single‐atomic transition metal–nitrogen–carbon (M–N–C) structures are promising alternatives toward noble‐metal‐based catalysts for oxygen reduction reaction (ORR) catalysis involved in sustainable energy devices. The symmetrical electronic density distribution of the M─N 4 moieties, however, leads to unfavorable intermediate adsorption and sluggish kinetics. Herein, a Fe–N–C catalyst with electronic asymmetry induced by one nearest carbon vacancy adjacent to Fe─N 4 is conceptually produced, which induces an optimized d‐band center, lowered free energy barrier, and thus superior ORR activity with a half‐wave potential ( E 1/2 ) of 0.934 V in a challenging acidic solution and 0.901 V in an alkaline solution. When assembled as the cathode of a Zinc–air battery (ZAB), a peak power density of 218 mW cm −2 and long‐term durability up to 200 h are recorded, 1.5 times higher than the noble metal‐based Pt/C+RuO 2 catalyst. This work provides a new strategy on developing efficient M–N–C catalysts and offers an opportunity for the real‐world application of fuel cells and metal–air batteries.