Triple‑Engineered Asymmetric Charge Localization on Fe Within a Fe–Cu Diatomic Motif Boosts Oxygen Reduction for Zinc–Air Battery

ABSTRACT Fe–N 4 centers are widely viewed as prospective sites for oxygen reduction reaction (ORR), yet improving their catalytic behavior through coordinated adjustments to structure and electronic properties remains difficult. Here, a C‐supported electrocatalyst with asymmetric Fe–Cu diatomic motifs is reported, in which a Fe atom bonded by S and N atoms couples with a neighboring Cu–N site (FeN 3 S–CuN 4 , denoted FeCu‐SNC). Operando spectroscopic characterizations and theoretical calculations show that stable adsorption of a hydroxyl (OH) intermediate on FeCu‐SNC produces a triply modulated Fe site with asymmetric coordination to S and Cu atoms, together with an additional hydroxyl intermediate during the catalytic process (FeCu─SN 5 –OH; the N 5 environment originates from the FeN 3 S moiety and the adjacent Cu site). This configuration generates an asymmetric surface charge distribution at the Fe center and weakens binding of reaction intermediates. Therefore, O 2 activation and conversion to the *OOH intermediate are promoted, accelerating ORR kinetics. FeCu‐SNC displays robust alkaline ORR kinetics, affording a half‐wave potential (E 1/2 ) of 0.914 V. When applied in rechargeable zinc–air batteries, it attains a maximum power output of 506 mW cm −2 . These results clarify how atomic‐ and electronic‐level modulation of heteronuclear Fe‐based diatomic sites can improve oxygen reduction catalysis.