High-Performance Visible-Light-Driven SnS2/SnO2 Nanocomposite Photocatalyst Prepared via In situ Hydrothermal Oxidation of SnS2 Nanoparticles

SnS2/SnO2 nanocomposites with tunable SnO2 contents were prepared via in situ hydrothermal oxidation of SnS2 nanoparticles in 0.375-4.5 mass% H2O2 aqueous solutions at 180 degrees C for 0-12 h. The structure, composition and optical properties of the as-prepared SnS2/SnO2 nanocomposites were characterized by X-ray diffraction, transmission electron microscopy, high-resolution transmission electron microscopy, Brunauer-Emmett-Teller (BET) surface area analysis, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and UV-vis diffuse reflectance spectra. Furthermore, their photocatalytic properties were tested for the degradation of methyl orange in water under visible light (lambda > 420 nm) irradiation. It was found that the as-prepared SnS2/SnO2 nanocomposites with suitable SnO2 content not only demonstrated superior photocatalytic activity to both SnS2 nanoparticles and physically mixed SnS2/SnO2 composite nanoparticles, but also had remarkable photocatalytic stability. The tight attachment of SnO2 nanoparticles to SnS2 nanoparticles, which can facilitate interfacial electron transfer and reduce the self-agglomeration of two components, was considered to play an important role in achieving the high photocatalytic performances exhibited by the as-prepared SnS2/SnO2 nanocomposites.