New SnS2/La2Ti2O7 heterojunction photocatalyst with enhanced visible-light activity

• Initiative study of the synthesis and properties of SnS2/La2Ti2O7 composite.
• SnS2/La2Ti2O7 nanoheterojunctions were synthesized by an in situ chemical method.
• Higher visible-light-driven photocatalytic activity than SnS2 and La2Ti2O7.

This work took the initiative to study the synthesis and photocatalytic properties of a new visible-light-active SnS2/La2Ti2O7 heterojunction photocatalyst. SnS2/La2Ti2O7 nanoheterojunctions were synthesized via hydrothermal treatment of SnCl4·5H2O, thioacetamide and La2Ti2O7 nanosheets in deionized water at 130 °C for 6 h. The structure, composition, and optical property of the as-synthesized SnS2/La2Ti2O7 nanoheterojunctions were characterized by powder X-ray diffraction, wavelength dispersive X-ray fluorescence spectroscopy, transmission electron microscopy and UV–vis diffuse reflectance spectra. The photocatalytic activity of the as-synthesized SnS2/La2Ti2O7 nanoheterojunctions was tested in the reduction of aqueous Cr(VI) under visible-light (λ>420 nm) irradiation, and compared with those of SnS2 nanoparticles and La2Ti2O7 nanosheets. It was observed that SnS2/La2Ti2O7 nanoheterojunctions exhibited much higher photocatalytic activity than SnS2 nanoparticles, whereas La2Ti2O7 nanosheets exhibited no photocatalytic activity in the reduction of aqueous Cr(VI) under visible-light (λ>420 nm) irradiation. The reasons accounting for the photocatalytic results were also proposed.