Holey Ni-Cu phosphide nanosheets as a highly efficient and stable electrocatalyst for hydrogen evolution

Abstract

Hydrogen, generated by electrocatalytic process, is one of the most promising sources of green and sustainable energy. Herein, we report a novel elctrocatalyst for hydrogen evolution reaction (HER) fabricated by doping Ni foam (NF) supported Ni2P nanosheets with Cu atoms. The Cu atoms effectively tune the structure and physicochemical properties of Ni2P, leading to the lower HER free energy, improved electrical conductivity, and high exposure of surface active sites. The optimized Ni1.8Cu0.2-P displays an excellent catalytic performance and stability, which is demonstrated by the low overpotentials of 78 (Tafel slope: 70 mV dec-1) and 245 mV to reach a current density of 10 and 100 mA cm-2 for the HER in 1.0 M KOH. The high electrocatalytic activity of Ni1.8Cu0.2-P is attributed to the increased Fermi level and the exposed active crystal plane (201). The H2 amount produced with a current density of 10 mA cm-2 is about 1.91 mmol h-1 cm-2, which is the highest value among the reported non-precious metal catalysts.