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

A series of Cd1−xZnxS (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 Cd1−xZnxS solid solutions. All Cd1−xZnxS/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 Cd1−xZnxS particles derived from the changes in the Zn concentration in the Cd1−xZnxS solid solution.

The present investigation deals with the deposition of Cd1−xZnxS nanoparticles inside the porous structure of an SBA-15 mesoporous substrate and the catalyst performance for the water splitting reaction under visible light irradiation. 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. This behavior is explained in terms of some type of electronic interaction between the nanoparticles and the support, and significant changes on the photocatalyst at structural and photo-optical levels. .Figure optionsDownload as PowerPoint slideHighlights
► All Cd1−xZnxS/SBA-15 samples exhibited enhanced activities for hydrogen evolution with respect the Zn-free counterpart.
► The Cd0.8Zn0.2S/SBA-15 photocatalyst exhibited the highest photoactivity.
► The value of bandgap of Cd1−xZnxS solid solutions was a function of Zn concentration.