Enhanced photocatalytic hydrogen evolution under visible light irradiation over Cd0.5Zn0.5S solid solution by magnesium-doping

A series of Mg doped Cd0.5Zn0.5S solid solution photocatalysts were prepared by a hydrothermal method and characterized by X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscope, BET, UV-Vis diffuse reflectance spectroscope and electrochemistry techniques. The photo activities were evaluated by hydrogen evolution from aqueous solution containing glucose as electron donor under visible light (lambda a parts per thousand yen 420 nm) irradiation. It was found that Mg2+ doping enhances the activity of Cd0.5Zn0.5S solid solution (with 0.5 wt% deposited Pt). When Mg(2+)doping is at 0.40 mol%, the photocatalyst exhibits the highest activity, 1.8 times that of Cd0.5Zn0.5S. This is attributed to the prevention of electron-hole recombination, the flat-band potential of the conduction of Mg(m)/Cd0.5Zn0.5S solid solution shifting negatively and the increased adsorption amount of glucose on Cd0.5Zn0.5S surface by Mg2+ doping. The stability test indicates that the catalyst is rather stable during 40 h of photoreaction.