Enhanced electrocatalytic activity of MoP microparticles for hydrogen evolution by grinding and electrochemical activation

Abstract

Transition metal phosphides like CoP, MoP, Ni₂P are suggested to be highly efficient catalysts for hydrogen evolution reaction (HER). However, HER-inert oxides would usually form on the surfaces of these phosphides during preparation and long-term storage. In this study, a simple combination method of grinding and electrochemical activation is used to tune the surface states of long-term stored commercial MoP microparticles, which show low activity for HER due to the molybdenum and phosphorus oxides on the surface, resulting in more exposed active sites of MoP and an enhanced catalytic activity for HER with an onset potential of 0.08 V vs. RHE and a Tafel slope of 50 mV dec⁻¹.