A synergistic catalyst of C 60 -confined Ag 3 Fe 2 and dual-metal sites for breaking activity and stability trade-off for oxygen reduction

Abstract

The commercialization of zinc-air batteries(ZABs) is hindered by the sluggish kinetics of the cathode oxygen reduction reaction (ORR). To address this issue, we synthesized a bimetallic catalyst (FeAg-N-C) in this work, featuring a multi-scale synergy of hierarchical pores, atomically dispersed Fe-N 6 and Ag-N 5 active sites along with C₆₀@Ag₃Fe₂ nanoparticles via an in situ strategy. The hierarchical pores and high specific surface area (1270.56 m² g -¹) facilitate efficient mass and electron transport.The C₆₀@Ag₃Fe₂/MOF interface tailors the electronic density of the Fe and Ag single atoms through a strong electronic coupling, achieving precise control over their catalytic properties. Meanwhile, in situ Raman reveals that Fe strongly attracts electrons from O atoms, while Ag acts as an electron donor to stabilize the adsorption configuration, highlighting the effective Fe-Ag synergy. Electrochemical tests indicate that FeAg-N-C exhibits excellent ORR activity in both alkaline and acidic media. When assembled into a zinc-air battery, it achieves a peak power density of 204 mW cm -², a specific capacity of 833 mAh g-1 Zn, and remarkable stability over 300 hours and 900 cycles. This work opens a pathway for the multi-scale synergistic enhancement of activity and stability in bimetallic single-atom catalysts.