Highly Efficient Photocatalytic Hydrogen Production over PdS@CdS+ZnS(en)0.5 Photocatalyst under Visible Light Irradiation

A new photocatalyst, CdS+ZnS­(en)0.5 (Cd/Zn = 6:4), was prepared by a simple mechanical mixing method and characterized by various techniques including X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, and UV–vis diffuse reflectance spectroscopy. The photocatalytic activity of CdS+ZnS­(en)0.5 was evaluated for hydrogen production from an aqueous solution under visible light. PdS-loaded CdS+ZnS­(en)0.5 exhibited an efficient H2 production rate of 2600 μmol h–1 g–1, which was higher than that observed with PdS-loaded CdS and Cd0.6Zn0.4S solid solution catalysts. The apparent quantum yield at 405 nm was 23%. Furthermore, PdS@CdS+ZnS­(en)0.5 showed good stability for prolonged H2 production reactions. It was proposed that enhancement of hole and electron transfer by PdS and ZnS­(en)0.5 contributed to the high activity of this photocatalyst for H2 production.