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.