Phosphorus doping of nickel–cobalt boride to produce a metal–metalloid–nonmetal electrocatalyst for improved overall water splitting

Abstract

Bifunctional materials with both hydrogen and oxygen evolution activity have received widespread attention for use in electrochemical applications. In the present study, an improved electrocatalyst with dual activity for the hydrogen and oxygen evolution reactions (HER and OER, respectively) is designed by adding a small amount of phosphorus to a nickel–cobalt boride (NCB) material. The cobalt and boron atoms act as active catalytic sites, while the nickel atoms assist in controlling the electronic structure of the material. The phosphorus dopant plays an active role in tuning the HER performance, while boron acts as a bridge between the metals and nonmetal in the P-NCB nano-catalyst. The water-splitting performance of the resulting catalyst benefits from the synergistic effects of these elements, which interact to form a unique structure that reduces the reaction energy barriers for both the HER and OER. The proposed metal–metalloid–nonmetal P-NCB electrocatalyst can thus facilitate the future development of more effective electrocatalysts with bifunctional properties.