Synergistically Promoting Oxygen Electrocatalysis through the Precise Integration of Atomically-Dispersed Fe Sites and Co Nanoparticles

Abstract

Oxygen electrochemistry, which encompasses the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER), is of utmost importance in energy-related reactions such as zinc-air batteries (ZABs). However, due to their four-electron transfer process, these reactions are still significantly restricted by sluggish reaction kinetics. Supporting atomically-dispersed (AD) catalyst or metal nanoparticles (NPs) on nitrogen-doped carbon (NC) is proven to be an effective strategy for enhancing the performance of oxygen electrocatalysis. Nevertheless, the performance of these types of catalysts still fails to meet the critical requirements for ZABs. Herein, a novel FeADCoNPs@NC, which consists of both AD Fe-N1 and Fe sites in the Co lattice, is developed. Spectroscopy studies and density functional theory calculations indicate that the Fe site in the Co lattice facilitates the conversion of Co NPs to an amorphous CoOOH, and the Fe-N1 serves as the main active site for ORR. FeADCoNPs@NC demonstrates remarkable activity for both OER and ORR. When it is used as an air-electrode for ZABs, it demonstrates a power density of 247.49 mW cm−2. This work presents a simple yet efficient method to enhance oxygen electrochemical performance through the synergy between AD sites and metal NPs.