Axial Cl‐Coordinated Porous FeCoZn Trimetallic Single‐Atom Catalysts: Breaking the Linear Scaling Relation for Superior Oxygen Reduction Reaction and Ultrastable Zinc‐Air Batteries

ABSTRACT

Single‐atom catalysts (SACs) have emerged as a research frontier in electrocatalysis. However, conventional SACs possess single metal active sites, which hardly break the symmetry of geometric and electronic structure of M–N ₄ . To address this limitation, porous trimetallic single‐atom catalysts (TACs) is fabricated via ZIF‐8‐derived ion exchange and gas‐phase etching methods. The catalyst features Fe, Co, and Zn single atoms with a special M–N ₄ configuration where the three metal atoms share one N ligand. And axial coordination structure exists between Zn and Cl atoms. It exhibits outstanding oxygen reduction activity and stability under acidic/alkaline conditions, with a half‐wave potential of 0.81 V/0.96 V and loss of 4 mV/8 mV after 30 000 cycles. Only 6.5% performance decay is observed after 2163 h of charge‐discharge cycling in zinc‐air batteries (ZABs). Physicochemical characterization and density functional theory (DFT) calculations reveal that the trimetallic configuration breaks the geometric and electronic structural symmetry, optimizing the adsorption of intermediates during the oxygen reduction reaction (ORR). Axial coordination of Cl on Zn facilitates the bridge‐type adsorption of O ₂ and breaks the linear scaling relationship. This work offers a novel strategy to break the symmetry of geometric and electronic structure of SACs and regulate reaction pathways.