Regulating the Electron Distribution of Atomically Dispersed Fe by Codoping of N and P for Highly Efficient Oxygen Reduction Reaction

Regulating the electron distribution for heterogeneous catalysts at the atomic level is a promising strategy to improve electrocatalytic performance. However, the underlying optimization mechanism and effective configuration structure design remain a challenge. Herein, atomically dispersed Fe species anchored on nitrogen, phosphorus-codoped carbon structures (Fe SAs@NPC) are developed with the screened hollow nanocube morphology. The as-prepared Fe SAs@NPC catalyst exhibits substantially improved electrocatalytic activity for oxygen reduction reaction (ORR) in both alkaline and acidic electrolytes with impressive half-wave potentials of 0.92 V vs reversible hydrogen electrode (RHE) and 0.83 V vs RHE in 0.1 M KOH and 0.5 M H2SO4, respectively. Furthermore, the fabricated Zn-air batteries based on Fe SAs@NPC exhibit a high power density of 161.2 mW cm–2 and a high specific capacity of 783.0 mAh g–1. Experiments and theoretical calculation results demonstrate that the electron distribution around Fe atoms is manipulated well, resulting in the favorable d-orbital distribution, the optimized desorption and adsorption capacity for oxygen intermediates, and the much-reduced reaction barrier, thereby improving the electrocatalytic performance and making Fe SAs@NPC one of the most excellent Fe-based single-atom ORR catalysts. This work shed light on the potential pathway to design the highly efficient catalyst at the atomic level by the effective electron regulation strategy.