Tuning the band-gap and enhancing the trichloroethylene photocatalytic degradation activities of flower-like Ni-doped SnS2/SnO2 heterostructures by partial oxidation

A hydrothermal procedure was used to synthesis flower-like 0-0.5 wt% Ni-doped SnS2, oxidation extent of which was tuned in air at 350 C for various times. Photocatalysts were dip-coated on coiled wire-meshes including a light source for oxidation of 500 ppm trichloroethylene in air. FE-SEM revealed that the SnS2 flower-like structure integrity was preserved after partial oxidation, while surface areas were dramatically enhanced. XRD, HR-TEM, Raman, XPS and PL showed formation of fine crystalline nanoparticles and defects by oxidation and resulted in enhanced photocatalytic activity. Band gaps and defects recombination rate of heterostructures were tuned by partial oxidation and Ni doping. 43% oxidation of 0.34 wt% Ni-doped SnS2 results in increased surface area by 7.7 times to 100 m(2)/g, quenched electrons and holes recombination, increased the band gap, and showed the highest TCE conversion of 88%, while the photocatalyst with no oxidation showed no activity. Further addition of Ni declined the surface area and photocatalytic conversion.

Automated summary

In this study, flower-like Ni-doped SnS2 was synthesized using a hydrothermal method, and its oxidation extent was controlled by air oxidation. The results showed that partial oxidation increased the surface area of SnS2 and enhanced its photocatalytic activity. Tuning the oxidation extent and Ni doping can regulate the band gap and defect recombination rate of heterostructures. The Ni-doped 0.34 wt% SnS2 with 43% oxidation showed the highest photocatalytic conversion.