Photocatalytic H 2 Evolution on CdS Loaded with WS 2 as Cocatalyst under Visible Light Irradiation

WS 2 /CdS photocatalysts with different amounts of WS 2 cocatalyst are prepared by loading WS 2 on CdS with an impregnation–sulfidation approach. The transformation process of the tungsten species loaded on CdS together with the junctions formed between WS 2 and CdS are clearly demonstrated with X-ray photoelectron spectroscopy and transmission electron microscopy. Photocatalytic H 2 production on WS 2 /CdS catalysts under visible light (λ > 420 nm) shows that WS 2 cocatalyst plays a crucial role in H 2 production. Under optimum conditions, the rate of H 2 evolution can be increased by up to 28 times when CdS was loaded with only 1.0 wt % WS 2, and WS 2 demonstrates a catalytic performance comparable or even superior to those of noble metals. Photocatalytic reaction results and electrochemical measurements indicate that the significantly enhanced H 2 evolution of WS 2 /CdS catalyst mainly owns to the junctions formed between WS 2 and CdS and the excellent performance of WS 2 as a cocatalyst in catalyzing H 2 evolution.