Highly Stable and Electrocatalytically Active Microflower‐Shaped, Fe 2 /Ni‐Coordinated N‐Doped Carbons With Vacancy Sites for Oxygen Redox Reactions

ABSTRACT Developing highly efficient and stable electrocatalysts for both the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) is vital for the large‐scale deployment of rechargeable zinc‐air batteries (ZABs). Herein, a novel ternary‐atom catalyst, composed of Fe 2 ‐ and Ni‐coordinated, flower‐shaped, N‐doped carbon microparticles containing carbon vacancy sites (Fe 2 /Ni‐N‐C CV MFs), is synthesized using a facile two‐step heat‐treatment strategy. The material possesses Fe 2 ‒N 6 and Ni‒N 4 co‐structures as well as abundant carbon vacancy sites. These render the material remarkable bifunctional electrocatalytic activity and outstanding stability in alkaline media. Density functional theory simulations indicate that: i) the Fe 2 ‒N 6 sites stabilize the reaction intermediate *OOH through bidentate adsorption, ii) the Ni‒N 4 sites favorably modulate the electronic states of Fe 2 ‒N 6 sites, and iii) the carbon vacancy sites around the metallic species hinder the dissolution of the metallic centers. Furthermore, the catalyst exhibits a high peak power density of 264.4 mW cm ‒2 and excellent long‐term cycling stability for 1000 h in rechargeable ZABs. This work will not only guide the development of robust multi‐atom catalysts through the rational modulation of multi‐metallic and vacancy sites, but also provide a new approach to optimizing the electronic structures of the metal centers in such catalysts to enhance electrocatalytic performance.