Understanding Synergistic Catalysis on Cu‐Se Dual Atom Sites viaOperandoX‐ray Absorption Spectroscopy in Oxygen Reduction Reaction

Abstract The construction and understanding of synergy in well‐defined dual‐atom active sites is an available avenue to promote multistep tandem catalytic reactions. Herein, we construct a dual‐hetero‐atom catalyst that comprises adjacent Cu‐N 4 and Se‐C 3 active sites for efficient oxygen reduction reaction (ORR) activity. Operando X‐ray absorption spectroscopy coupled with theoretical calculations provide in‐depth insights into this dual‐atom synergy mechanism for ORR under realistic device operation conditions. The heteroatom Se modulator can efficiently polarize the charge distribution around symmetrical Cu‐N 4 moieties, and serve as synergistic site to facilitate the second oxygen reduction step simultaneously, in which the key OOH*‐(Cu 1 ‐N 4 ) transforms to O*‐(Se 1 ‐C 2 ) intermediate on the dual‐atom sites. Therefore, this designed catalyst achieves satisfied alkaline ORR activity with a half‐wave potential of 0.905 V vs. RHE and a maximum power density of 206.5 mW cm −2 in Zn‐air battery.