Preparation of Cu-doped ZnS QDs/TiO2 nanocomposites with high photocatalytic activity

Cu-doped ZnS quantum dots (QDs) were synthesized in aqueous solution using 3-mercaptopropionic acid (MPA) as stabilizer. Transmission electron microscopy (TEM) results indicate that the Cu:ZnS nanocrystals distribute uniformly and the size is ca. 2.9 +/- 0.5 nm. These nanocrystals were successfully associated to anatase TiO2 nanoparticles to yield TiO2/Cu:ZnS photocatalysts. Morphological and optical properties of TiO2/Cu:ZnS nanocomposites were characterized by X-ray diffraction (XRD) analysis, TEM, and UV-vis and fluorescence spectroscopies. Photocatalytic activities of TiO2/Cu:ZnS nanocomposites were evaluated by the oxidation of salicylic acid aqueous solutions under UV light irradiation. Enhanced performances compared either to pure TiO2 nanoparticles or to undoped TiO2/ZnS nanocomposites were observed. Effects of the mass ratio of the TiO2 and Cu:ZnS and of the pH of the aqueous solution containing salicylic acid on the photocatalytic activities of TiO2 nanoparticles sensitized with Cu:ZnS QDs were also investigated. (C) 2013 Elsevier B.V. All rights reserved.