Modulating electronic structure of Ni2P pre-catalyst by doping trace iron for enhanced oxygen evolution reaction in alkaline

Abstract

Electrochemical water splitting for hydrogen production is of great significance in exploring sustainable energy for the upcoming low-carbon era, the discovery of electrocatalysts with high activity and inexpensive is highly important to expedite the extremely sluggish kinetics of oxygen evolution reaction (OER). Herein, an efficient OER electrocatalyst was designed by doping trace Fe into Ni 2 P via a simple structural transformation. The crystal structure and surface chemical state analysis demonstrated the introduction of Fe dopant and the successful formation of the host Ni 2 P. As-prepared Fe-Ni 2 P microspheres greatly optimized the intrinsic activity of the active site and accelerated the mass transfer rate. Intriguingly, the electrochemical tests certified that trace Fe doping can increase the activity of nickel phosphide more significantly. High valence state transition from Ni P bond to Ni O bond was clearly observed, suggesting the new active species can be easily formed during OER. This article provides a trace Fe doping strategy for the study of efficient electrocatalysts to improve the kinetics of OER. The mechanism diagram demonstrates electrocatalytic oxygen evolution. The structure of Ni 2 P is regulated by trace Fe doping, which ultimately significantly improves OER performance. • Trace Fe doping can promote the conversion of the active site from Ni P bond to Ni O/OH. • Trace Fe doping can increase the activity of nickel phosphide more significantly. • The synergistic effect of Fe-Ni bimetallic sites accelerates OER kinetics.