Spatial charge separation of one-dimensional Ni₂P-Cd_0.9Zn_0.1S/g-C₃N₄ heterostructure for high-quantum-yield photocatalytic hydrogen production

Constructing heterostructured photocatalysts to facilitate spatial charge separation is deemed to be central to improving photocatalytic hydrogen production. Herein, we reported the synthesis of Ni₂P-Cd_0.9Zn_0.1S/graphitic carbon nitride (g-C₃N₄) heterostructure for photocatalytic hydrogen production under visible-light irradiation. It was revealed that the ternary photocatalysts exhibited a one-dimensional morphology. Ni₂P nanoparticles and a layer of g-C₃N₄ were tightly deposited on the surface of Cd_0.9Zn_0.1S nanorods. The optimal hydrogen evolution rate over Ni₂P-Cd_0.9Zn_0.1S/g-C₃N₄ was ∼2100 μmol h⁻¹ mg⁻¹, corresponding to an apparent quantum yield as high as 73.2% at 420 nm. Meanwhile, the g-C₃N₄ layer could effectively collect the photo-induced holes from Cd_0.9Zn_0.1S, which substantially alleviated the photocorrosion of metal sulfide and led to an excellent stability for 90 h. A detail analysis of the action mechanism by photoluminescence, surface photovoltage, and electrochemical measurements revealed that the dramatically improved photocatalytic activity should be ascribed to highly efficient spatial separation of photo-induced charge carriers, as well as accelerated surface reaction by Ni₂P cocatalysts. It is believed that the present work supplies an effective way to obtain non-precious heterostructured photocatalytic system for high-quantum-yield and stable hydrogen production.