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

Abstract This work took the initiative to study the synthesis and photocatalytic properties of a new visible-light-active SnS 2 /La 2 Ti 2 O 7 heterojunction photocatalyst. SnS 2 /La 2 Ti 2 O 7 nanoheterojunctions were synthesized via hydrothermal treatment of SnCl 4 ·5H 2 O, thioacetamide and La 2 Ti 2 O 7 nanosheets in deionized water at 130 °C for 6 h. The structure, composition, and optical property of the as-synthesized SnS 2 /La 2 Ti 2 O 7 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 SnS 2 /La 2 Ti 2 O 7 nanoheterojunctions was tested in the reduction of aqueous Cr(VI) under visible-light ( λ >420 nm) irradiation, and compared with those of SnS 2 nanoparticles and La 2 Ti 2 O 7 nanosheets. It was observed that SnS 2 /La 2 Ti 2 O 7 nanoheterojunctions exhibited much higher photocatalytic activity than SnS 2 nanoparticles, whereas La 2 Ti 2 O 7 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.