Preparation of visible light-driven SnS2/TiO2 nanocomposite photocatalyst for the reduction of aqueous Cr(VI)

SnS2/TiO2 nanocomposites with adjustable TiO2 contents were prepared via solvothermal treatment of different amounts of tetrabutyl titanate in the presence of SnS2 nanoparticles in the mixed solvents of ethanol and acetic acid at 180 degrees C for 12 h. The structures, compositions, BET specific surface areas and optical properties of the as-prepared products were characterized by X-ray diffraction, energy dispersive X-ray spectroscopy, transmission electron microscopy, high resolution transmission electron microscopy, N-2 adsorption and UV-Vis diffuse reflectance spectra, and their photocatalytic properties were tested by the reduction of aqueous Cr(VI) under visible light (lambda > 420 nm) irradiation. It was found that the photocatalytic activities of the as-prepared SnS2/TiO2 nanocomposites depended on their compositions, and SnS2/TiO2-B containing 25.5 mass% TiO2 not only displayed the highest photocatalytic activity, but also exhibited a good photocatalytic stability. Meanwhile, the reasons accounting for the photocatalytic results were also discussed. Besides, X-ray photoelectron spectroscopy analysis revealed that Cr(VI) was reduced to Cr(III) after the photocatalytic reactions over SnS2/TiO2-B. (c) 2012 Elsevier B.V. All rights reserved.