Atomically dispersed trimetallic oxygen electrocatalysts for advancing rechargeable zinc-air battery

Developing efficient non-precious metal catalysts for oxygen electrocatalysis is crucial for advancing renewable energy storage systems such as rechargeable Zn-air batteries. Nitrogen-doped carbon (M-N-C) materials with atomically dispersed metal sites, particularly Fe-N-C, exhibit remarkable activity for the oxygen reduction reaction (ORR); however, their performance in the oxygen evolution reaction (OER) remains unsatisfactory. In this work, we present the fabrication of Fe, Co, and Ni trimetallic single-atom catalysts, which exhibit outstanding bifunctional catalytic performance. Using ZIF-8 and phytic acid as chelating agents, we achieved uniform dispersion of Fe, Co, and Ni atoms within a porous carbon matrix, preventing metal agglomeration and enhancing catalytic performance. The Fe30Co30Ni30-phosphorus and nitrogen doped carbon (PNC) catalyst, after optimization, achieved a half-wave potential of 0.85 V for ORR and an OER overpotential of 310 mV at 10 mA·cm-2, outperforming many state-of-the-art non-precious metal catalysts. When applied in a Zn-air battery, it achieved a peak power density of 221 mW·cm-2, a specific capacity of 791.3 mAh·gZn-1, and remarkable durability over 330 h. This study offers an efficient approach for developing high-performance catalysts for renewable energy applications.