Multimetallic Single-Atom Catalysts for Bifunctional Oxygen Electrocatalysis

Multimetallic alloys have demonstrated promising performance for the application of metal-air batteries, while it remains a challenge to design multimetallic single-atom catalysts (MM-SACs). Herein, metal-C(3)N(4 )and nitrogen-doped carbon are employed as cornerstones to synthesize MM-SACs by a general two-step method, and the inherent features of atomic dispersion and the strong electronic reciprocity between the multimetallic sites have been verified. The trimetallic FeCoZn-SACs and quatermetallic FeCoCuZn-SACs are both found to deliver superior oxygen evolution reaction and oxygen reduction reaction activity, respectively, as well as outstanding bifunctional durability. Density functional theory calculations elucidate the crucial contribution of Co sites of FeCoCuZn-SACs to the efficient catalysis of both the ORR and the OER. More importantly, Zn-air batteries with FeCoCuZn-SACs as cathodic catalysts exhibit a high power density (252 mW cm(-2)), high specific capacity (817 mAh g(Zn)(-1)), and considerable stability (over 225 h) for charging-discharging processes. This work provides a visual perspective for the advantages of MM-SACs toward oxygen electrocatalysis.

Automated summary

This study successfully synthesized multimetallic single-atom catalysts (MM-SACs) using metal-C(3)N(4) and nitrogen-doped carbon as cornerstones, and verified their atomic dispersion and strong electronic reciprocity between multimetallic sites. It was found that FeCoZn-SACs and FeCoCuZn-SACs exhibited superior oxygen evolution reaction and oxygen reduction reaction activity, as well as outstanding bifunctional durability. The Co sites in FeCoCuZn-SACs were crucial contributors to the efficient catalysis of both ORR and OER. Furthermore, Zn-air batteries with FeCoCuZn-SACs as cathodic catalysts showed high power density, specific capacity, and stability for charging-discharging processes.