Nanoscale ZnS/TiO2 composites: Preparation, characterization, and visible-light photocatalytic activity

Photoactive ZnS/TiO2 nanocomposites were prepared via microemulsion-mediated solvothermal method. The structure, composition, physicochemical property, and morphology of the composites were characterized by powder X-ray diffraction (XRD), Raman scattering studies, UV diffuse reflectance spectroscopy (UV/DRS), photoluminescence (PL) spectroscopy, and transmission electron microscopy (TEM). It showed that the composites were cube-shaped with particle sizes of 10 to 15 nm, and the phase structure for ZnS and TiO2 in the composites was cubic and anatase, respectively. The content of the ZnS in the composites was 2.1%, 10.7%, and 19.9%, respectively. Compared with the solitary anatase TiO2, the ZnS/TiO2 exhibited enhanced visible-light photocatalytic activity for the aqueous parathion-methyl degradation. Factors including the interactions between the phases of ZnS and TiO2, strong adsorption of the substrate at the surface of the ZnS/TiO2 nanocomposites, and preassociation of the substrate and composites are responsible for this enhancement photocatalytic activity.