Colloidal synthetic methods of amorphous molybdenum phosphide nanoparticles for hydrogen evolution reaction catalysts

Transition metal phosphides (TMPs) have recently emerged as promising hydrogen evolution reaction (HER) catalytic alternatives to platinum. Among them, molybdenum phosphide (MoP) has attracted extensive attention due to its high electrical conductivity, good stability, and Pt-like electronic structure; however, there is no systematic comparison of its different colloidal synthetic routes. This study systematically compares two colloidal synthetic methods, one-pot and two-step, for amorphous MoP and the associated morphological changes during their reaction time. The amorphous MoP nanoparticles synthesized via the two-step method within 4 h exhibited the highest HER performance with an overpotential of 177 mV in 0.50 M H2SO4 for a current density of −10 mA cm−2; this might be due to their highly developed Mo-P bondings revealed by X-ray photoelectron spectroscopy analysis. Thus, this work demonstrates that the HER catalytic performance of MoP can be significantly influenced by its synthetic method and reaction time.