Enhanced Schottky Effect in the Ni2P Cocatalyst via Work Function Up-Shift Induced by MoO2 for Boosting Photocatalytic Hydrogen Evolution

Transition metal phosphides are considered to be promising cocatalysts that can be used to improve the photocatalytic hydrogen production performance. However, the relatively low conductivity, high overpotential, and limited interface driving force between the photocatalysts hamper their activity. In this study, we introduce work function engineering via MoO2 modification to modulate the Fermi energy level of Ni2P to obtain an enhanced Schottky effect in the photocatalytic hydrogen evolution reaction (HER). Moreover, heterojunction engineering of MoO2/Ni2P decreases the adsorption energy of hydrions and facilitates the electrical conductivity and kinetics of HERs. The trifecta of MoO2 in hybrid cocatalysts significantly promotes the neutral photocatalytic HER efficiency of g-C3N4. Therefore, the as-prepared MoO2/Ni2P@g-C3N4 composite shows excellent photocatalytic HER performance, which reaches up to 1.38 times that of Pt-modified g-C3N4. Hence, this study provides in-depth insights into the simultaneous utilization of the work function and heterojunction modulation of cocatalysts to improve the photocatalytic HER performance.