Construction of the Ni₂P/MoP Heterostructure as a High-Performance Cocatalyst for Visible-Light-Driven Hydrogen Production

Transition metal phosphides are regarded as promising cocatalysts for photocatalytic hydrogen evolution, although there are still many limitations, such as a relatively lower electrical conductivity and a higher overpotential than noble metals, hampering their real applications. In this work, the Ni2P/MoP heterostructure is constructed by the phosphorization reaction on the presynthesized NiMoO4·xH2O nanorod precursor. The Ni2P/MoP heterostructure exhibits an improved electrical conductivity and a lower overpotential with respect to Ni2P and MoP. Density functional theory calculations for the heterostructure further reveal the greatly increased density of states near the Fermi level with more obvious metallic characteristics as well as a closer-to-neutral Gibbs free energy of hydrogen adsorption. After coupling with graphitic carbon nitride, the photocatalyst shows a remarkable activity in hydrogen production under visible light irradiation. The theoretical prediction and experimental demonstration highlight the great potential of transition-metal phosphide-based heterostructures as high-performance and precious-metal-free cocatalysts for visible-light-driven hydrogen evolution.