Effects of Composition and Calcination Temperature on Photocatalytic H2 Evolution over Cd1-x Znx S/SiO2 from Glycerol and Water Mixture

A series of sulfide coupled semiconductors supported on SiO2, [subscript]Cd1-x[/subscript] [subscript]Znx[/subscript] S/[subscript]SiO2[/subscript] ( x=0~1 ), was prepared by incipient wet impregnation method. The photocatalysts were characterized by XRD, XPS, TPR, and UV/Vis DRS. Characterization results show that the chemical actions between ZnS and CdS resulted in the formation of [subscript]Cd1-x[/subscript] [subscript]Znx[/subscript] S solid solutions on the surface of the support and the formation of them is affected by the molar ratio of ZnS/CdS and calcination temperature. Performance of photocatalysts was tested in the home made reactor under both UV light and solar-simulated light irradiation by detecting the rate of the photocatalytic H2 evolution from glycerol solution. The hydrogen production rates are related to the catalyst composition, surface structure, photoabsorption property, as well as the amount of solid solution. The maximum rate of hydrogen production, 550 μmol·h-1 under UV light irradiation and 210 μmol·h-1 under solar-simulated light irradiation, was obtained over Cd0.8Zn0.2S/SiO2 solid solution calcined at 723 K.