SnS2 nanoplates/SnO2 nanotubes composites as efficient visible light-driven photocatalysts for Cr(VI) reduction

SnS2/SnO2 nanocomposites have been successfully prepared via a hydrothermal method using electrospun SnO2 nanotubes as both substrates and reactants. The ratios of the nanocomposites are controlled by varying the concentration of thioacetamide during the solvothermal synthesis processes. The as-prepared SnS2/SnO2 nanocomposites exhibit considerable improvement on the photocatalytic activities for the reduction of aqueous Cr(VI) under visible light irradiation. Their photoactivities are also much higher than that of SnS2 nanoplates and a physical mixture of SnO2 and SnS2. In particular, the SnS2/SnO2-B sample exhibits the highest photocatalytic activity. After visible light irradiation for 60 min, the reduction rate has reached about 100%. The photoelectrochemical analyses further show that the high photocatalytic activity of the SnS2/SnO2-B sample can be ascribed to the unique structural features and the intimate interfacial contact between SnS2 and SnO2, which is more effective separation of the photo-generated carriers.