Synergistic Cu–Zn Dual-Atom Sites in Hierarchically N-Doped Porous Carbon Enable Efficient Rechargeable Zn–Air Batteries

Abstract

Herein, we report an atomically well-defined Cu–Zn dual-atom catalyst featuring isolated Cu–N4 and Zn–N4 moieties embedded in a hierarchical N-doped carbon framework. Through controlled precursor chemistry and defect engineering, the spatial proximity and electronic coupling between the two metal centers are precisely regulated, enabling the construction of stable dual-atom catalytic sites with distinct electronic characteristics. Electrochemical measurements reveal that the optimized CuZn-NC catalyst exhibits enhanced oxygen reduction reaction (ORR) activity, characterized by a positive onset potential (0.99 V) and a half-wave potential (0.88 V), together with excellent durability and methanol tolerance. Combined spectroscopic analyses and density functional theory calculations demonstrate that the cooperative interaction between adjacent Cu–N4 and Zn–N4 sites effectively modulates the adsorption energetics of oxygenated intermediates, thereby lowering the reaction energy barriers and accelerating ORR kinetics. When evaluated as an air cathode, the catalyst further delivers an impressive peak power density of 331.8 mW cm–2 and stable discharge operation over 333 h. This work provides mechanistic insights into dual-metal single-atom cooperation and offers a rational strategy for designing advanced oxygen electrocatalysts.