A robust PtFeNi triatomic catalyst for efficient oxygen electrocatalysis and stable Zn-air batteries

Rechargeable zinc-air batteries hold great potential for various applications, and their development hinges on the availability of bifunctional catalysts that exhibit outstanding oxygen reduction/evolution reaction (ORR/OER) performance. Therefore, robust bifunctional oxygen electrocatalysts are vital to the functionality and recharge cycling durability of zinc-air batteries. Our work focuses on employing a two-step method of node substitution followed by electrostatic adsorption to embed Ni, Fe, and Pt atoms onto graphene nanosheets, successfully constructing a three-atom catalyst (Ni, Fe, Pt)-N-C. Theoretical calculations elucidate the active sites for ORR and OER, along with synergistic interatomic coupling between metal centers that disrupts electronic symmetry, thereby modulating the local electronic states to facilitate oxygen intermediates’ adsorption/desorption. In electrochemical tests, (Ni, Fe, Pt)-N-C also exhibits outstanding performance for both the ORR, with a half-wave potential of 0.906 V, and the OER, achieving a potential of 1.601 V at 10 mA/cm². Zinc-air batteries assembled from (Ni, Fe, Pt)-N-C can easily deliver a current exceeding 300 mA/cm², with a peak power density reaching 175 mW/cm². In a 300-cycle charge-discharge test at a current density of 10 mA/cm², the (Ni, Fe, Pt)-N-C catalyst exhibits smaller overpotentials and more stable cycling performance compared to commercial Pt/C & Ir/C. This work reveals that the synergistic interaction of metal atoms in the triatomic catalyst plays a crucial role in breaking electronic symmetry.