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

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.