Spatial charge separation of one-dimensional Ni2P-Cd0.9Zn0.1S/g-C3N4 heterostructure for high-quantum-yield photocatalytic hydrogen production

•A novel one-dimensional Ni2P-Cd0.9Zn0.1S/g-C3N4 heterostructure is constructed for photocatalytic hydrogen production.•The apparent quantum yield over noble-metal-free Ni2P-Cd0.9Zn0.1S/g-C3N4 reaches 73.2% at 420 nm.•The efficient spatial charge separation and accelerated surface reaction, cooperatively boost photocatalytic hydrogen production.•The g-C3N4 protective layer effectively alleviates the photocorrosion of Cd0.9Zn0.1S, leading to an excellent stability for 90 h.

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-Cd0.9Zn0.1S/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 Cd0.9Zn0.1S nanorods. The optimal hydrogen evolution rate over Ni2P-Cd0.9Zn0.1S/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 Cd0.9Zn0.1S, 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.

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