One-step in situ solvothermal synthesis of SnS2/TiO2 nanocomposites with high performance in visible light-driven photocatalytic reduction of aqueous Cr(VI)

SnS2/TiO2 nanocomposites with adjustable TiO2 contents were synthesized directly via the solvothermal reactions of SnCl4·5H2O, thioacetamide and different amounts of tetrabutyl titanate in the mixed solvents of ethanol and acetic acid at 180 °C for 12 h. The structures, compositions, Brunauer–Emmett–Teller (BET) specific surface areas and optical properties of the as-synthesized products were characterized by X-ray diffraction, energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, field emission scanning electron microscopy, high resolution transmission electron microscopy, N2 adsorption and UV–vis diffuse reflectance spectra, and their photocatalytic properties were tested for the reduction of aqueous Cr(VI) under visible light (λ > 420 nm) irradiation. Furthermore, contrast photocatalytic experiments were also conducted for different doses of the as-synthesized SnS2/TiO2 nanocomposite, SnS2 and physical mixture of SnS2 and TiO2. It was found that the as-synthesized SnS2/TiO2 nanocomposite with a suitable TiO2 content (e.g., 44.5 mass% TiO2) not only exhibited extraordinary superior photocatalytic activity to SnS2, TiO2 and physical mixture of SnS2 and TiO2 (44.5 mass%) at different catalyst doses, but also had good photocatalytic stability. Moreover, Cr(VI) can be reduced to Cr(III) by SnS2/TiO2-mediated photocatalysis. The tight heterojunction structure of the as-synthesized SnS2/TiO2 nanocomposite, which can facilitate interfacial electron transfer and reduce the separation and self-agglomeration of two components, was considered to play an important role in achieving its greatly improved photocatalytic performance.

Figure optionsDownload as PowerPoint slideHighlights▸ SnS2/TiO2 nanocomposites are synthesized by a one-step in situ solvothermal route. ▸ Photocatalytic activities depend on compositions. ▸ Higher activity than SnS2, TiO2 and SnS2/TiO2 physical mixture at different doses. ▸ Good photocatalytic stability. ▸ Cr(VI) is reduced to Cr(III).