Atomically Dispersed Fe 2 and Ni Sites for Efficient and Durable Oxygen Electrocatalysis

Abstract Developing highly efficient, cost‐effective, and robust electrocatalysts for the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) is paramount for the large‐scale commercialization of renewable fuel cells and rechargeable metal‐air batteries. Herein, a new ternary‐atom catalyst that is composed of paired Fe sites and single Ni sites (as Fe 2 −N 6 and Ni−N 4 ) coordinated onto hollow nitrogen‐doped carbon microspheres is developed. The as‐synthesized catalyst exhibits remarkable activities toward both the ORR and OER in alkaline media, with superior performances to those of the control materials that contain only Fe 2 −N 6 or Ni−N 4 sites. Density functional theory calculations and in situ infrared (IR) spectroscopic studies clearly reveal that the Fe 2 −N 6 centers are the active sites for both ORR and OER, and their electrocatalytic activities are synergistically enhanced through optimization of their d‐band centers by the Ni−N 4 sites. This ternary‐atom catalyst can potentially be a promising, alternative, sustainable catalyst to commercially used Pt‐ and Ru‐based catalysts to drive both the ORR and the OER in rechargeable zinc‐air batteries and other related applications.