In Situ TiO2-Decorated SnS2 Nanoheterostructures for Enhanced Photocatalytic Hydrogen Generation

Abstract

The synthesis of TiO₂-decorated SnS₂ nanosheets with varying concentrations of Ti from 5 to 20 mol % (5 mol %, 10 mol %, 15 mol %, and 20 mol %) was carried out, and their several physicochemical and photocatalytic characteristics were investigated. The hydrothermal method was utilized for the in situ synthesis of TiO₂ decorated on SnS₂ hexagonal nanosheets. The XRD indicates the formation of the highly crystalline hexagonal phase of SnS₂ and anatase phase of TiO₂. Further, the as-prepared TiO₂–SnS₂ nanophotocatalyst shows absorption behavior in the UV–visible region, and photoluminescence spectra of the TiO₂–SnS₂ nanostructures show band edge emission along with the peaks attributed to the defects. The formation of hexagonal SnS₂ sheets with uniformly dispersed TiO₂ nanoparticles and SnS₂ nanosheets is confirmed by the FE-SEM and FE-TEM. As TiO₂ loading increased, it was found that the BET surface area also improved. The photocatalytic activity of the synthesized TiO₂–SnS₂ nanosheets was assessed for hydrogen generation via water reduction under a 400 W mercury vapor lamp as the light source. Among the prepared TiO₂–SnS₂ nanostructures, the TiO₂ loaded with 15 mol % provides the maximum hydrogen generation, i.e., 2464.9 μmol/0.1gm in 4 h, nearly 2.8 times more than that of pristine SnS₂, i.e., 846.1 μmol/0.1gm. This demonstrates that TiO₂–SnS₂ could be an auspicious photocatalyst agent for H₂ production via water reduction. Moreover, the photocatalytic activity of the prepared nanostructures is also correlated with the photoconductivity by the photocurrent measurement. Higher the photocurrent, higher is the photocatalytic performance of the prepared nanostructures.