Cd1−xZnxS solid solutions supported on ordered mesoporous silica (SBA-15): Structural features and photocatalytic activity under visible light

A series of Cd_1−xZn_xS (x = 0.05–0.3) photocatalysts supported on ordered mesoporous silica (SBA-15) were prepared and investigated for hydrogen production from water splitting under visible light. Textural, structural and surface photocatalyst properties are determined by N₂ adsorption isotherms, UV–vis, Raman and XPS and related to the activity results in hydrogen production. Raman and XRD results indicated a mutual interaction between Cd and Zn, forming nanoparticles of Cd_1−xZn_xS solid solutions. All Cd_1−xZn_xS/SBA-15 samples showed relatively high activities for hydrogen evolution. The hydrogen production rate is found to increase gradually when the zinc concentration on photocatalysts increases from 0.05 to 0.2, achieving a maximum for the photocatalyst with zinc concentration equal to 0.2. Variation in photoactivity is discussed in terms of modification in the conduction band and light absorption ability of Cd_1−xZn_xS particles derived from the changes in the Zn concentration in the Cd_1−xZn_xS solid solution.