In situ growth of urchin-like cobalt–chromium phosphide on 3D graphene foam for efficient overall water splitting

Abstract

The preparation of an Earth-abundant, highly efficient and durable bifunctional electrocatalyst for water electrolysis is indispensable and in great demand. Herein, a bifunctional catalyst, cobalt–chromium phosphide (Co₂Cr₁-P) merged with a substrate of three-dimensional graphene foam (3DGF), was reported. The Co₂Cr₁-P@3DGF composite demonstrates remarkable electrocatalytic activities for the production of hydrogen and oxygen in 1.0 M KOH, which only requires a low overpotential of 118 and 270 mV to afford 10 mA cm⁻², respectively. Additionally, when applying Co₂Cr₁-P@3DGF as a catalytic electrode for alkaline overall water splitting, the demanded cell voltage at 10 mA cm⁻² is merely 1.56 V. The superior performance is attributable to the incorporation of the Cr element into CoP and the good conductivity of the 3D graphene network substrate.