A Highly Active and Stable Single-Atom Catalyst for Oxygen Reduction with Axial Fe-O Coordination Prepared Through a Fast Medium-Temperature Pyrolysis Process

In this study, we developed a highly active and stable Fe single atomic catalyst with axial Fe-O coordination through a fast medium-temperature pyrolysis process. The catalyst exhibited a high ORR performance, with a high half-wave potential of 0.93 V (vs. RHE), as well as excellent stability. When incorporated in a zinc-air battery's air electrode, a high power density of 214.5 mW cm-2 was obtained. After 333 h cyclic chargingdischarging test, no obvious performance decay was observed. Density functional theory calculations revealed that the axial Fe-O coordination optimized the interactions between Fe and intermediates, inhibited the demetallization of Fe single atomic active sites and eventually enhanced the performance and stability of the obtained catalyst. We believe that the present strategy is easily translatable to the rational design of highly active and stable ORR catalysts for eco-friendly and future-oriented energy applications.