Photocatalytic properties of SnS2/SnO2 nanocomposite prepared by thermal oxidation of SnS2 nanoparticles in air

An alternative in situ chemical method, which was based on thermal oxidation of SnS2 nanoparticles in air at 300 degrees C for 3 h, was proposed for the preparation of SnS2/SnO2 nanocomposite (SnS2/SnO2-TO). The photocatalytic properties of SnS2/SnO2-TO were tested by the reduction of aqueous Cr(VI) under visible-light (lambda > 420 nm) irradiation, and compared with those of SnS2 nanoparticles, SnO2 nanoparticles and SnS2/SnO2-PM (which denotes the physically mixed SnS2/SnO2 nanocomposite with the same composition as SnS2/SnO2-TO). Besides, the effects of the coexistence of some organic compounds (e.g., phenol, rhodamine B (RhB) and methyl orange (MO)) on SnS2/SnO2-TO-mediated photocatalytic reduction of aqueous Cr(VI) were also studied. It was observed that (i) SnS2/SnO2-TO not only displayed higher visible-light-activated photocatalytic activity than SnS2, SnO2 and SnS2/SnO2-PM, but also displayed good reusability in the reduction of aqueous Cr(VI); and (ii) the coexistence of phenol and RhB enhanced the photocatalytic reduction of Cr(VI), whereas the coexistence of MO retarded the photocatalytic reduction of Cr(VI) over SnS2/SnO2-TO. The reasons accounting for the photocatalytic results were also discussed. (C) 2013 Elsevier B.V. All rights reserved.