Chemically bonded Co2P-Cu3P heterostructure nanoparticles on porous carbon framework as efficient hydrogen evolution/oxidation electrocatalysts

Abstract

Exploring economical and efficient catalysts for hydrogen evolution/oxidation reaction (HER/HOR) is very crucial for water splitting and fuel-cells applications. Constructing transition metal phosphides heterostructures is a representative strategy to accelerate kinetics. Herein, we designed Co₂P-Cu₃P heterostructure particles on a porous carbon skeleton (Co₂P-Cu₃P/C) for the HER/HOR. The Co₂P-Cu₃P/C possesses a suitable specific surface area, an optimized electronic structure, and strong chemical bridge bonds (C-P-Co(Cu)) between porous carbon skeleton and Co₂P-Cu₃P nanoparticles, resulting in a substantial increase in its HER/HOR activity and enhanced stability. Therefore, Co₂P-Cu₃P/C only requires a low overpotential of 90 mV to reach a current density of 10 mA cm⁻² with a low Tafel slope of 53.5 mV dec^-1, and it can maintain the HER over long-term (72 h). Moreover, Co₂P-Cu₃P/C also has potential in applications due to its excellent HER performance. Furthermore, the Co₂P-Cu₃P/C exhibits a superior intrinsic activity of 1.19 mA cm⁻² and excellent durability (500 min) for the HOR. Density functional theory calculations indicate that the interfacial effect between Co₂P and Cu₃P at the heterogeneous interfaces contributes to the enhanced HER/HOR performance.