Mechanistic insights of enhanced photocatalytic efficiency of SnO2-SnS2 heterostructures derived from partial sulphurization of SnO2

Visible-light-active materials with high charge carrier transfer efficacy and low electron-hole recombination rate are desirable for an efficient photocatalyst. In view of this, here, we have synthesized SnO2-SnS2 heterostructures via hydrothermal route. The optical properties of SnO2-SnS2 heterostructure shows the band gap of heterostructure is in visible region (2.6 eV) compared to pure SnO2 (3.7 eV). Further, the photocatalytic degradation activity of SnO2-SnS2 heterostructure was investigated thoroughly and the insight of photocatalytic mechanism were analyzed by electrochemical studies. The SnO2-SnS2 heterostructure is found to be an efficient photocatalyst with photo-degradation efficiency similar to 99% for methyl orange under visible light. The diminished PL intensity in case of heterostructures implies the decrease in recombination time of charge carriers as well as efficient charge transfer between SnO2 and SnS2 which is a major factor in the enhancement of photoactivity of SnO2-SnS2 heterostructure.