Strategic Engineering of Axially Coordinated Ligands in Fe‐N‐C Catalysts for Enhanced Oxygen Reduction Electrocatalysis

The single‐atom Fe‐N‐C electrocatalyst is considered one of the most promising alternatives to the expensive and scarce Pt‐based catalysts for promoting oxygen reduction reaction (ORR) in fuel cells. Regulating the coordination environment of the Fe center is a feasible strategy to improve its stability and catalytic activity. Recently, the introduction of axial ligands to Fe‐N‐C has attracted extensive research interest, providing a new dimension for coordination environment regulation compared with the common approaches of in‐plane doping or defect construction. This review focuses on discussing the contribution of axial ligands decoration to the activity and stability of the Fe‐N‐C catalyst, evaluating different types of axial ligands that have been introduced in recent literature. Through summarizing the progress in decorating axial ligands to the Fe‐N‐C system, this review provides profound insights for the design and preparation of axially coordinated Fe‐N‐C catalysts.