Scalable low temperature in air solid phase synthesis of porous flower-like hierarchical nanostructure SnS2 with superior performance in the adsorption and photocatalytic reduction of aqueous Cr(VI)

Nanosheets-constructed porous flower-like hierarchical nanostructure SnS2 (which was labeled as F-SnS2) was synthesized by heating the mixture of SnCl2·2H2O and thiourea in air at 170 °C for 2 h, in combination with a subsequent washing with water. F-SnS2 exhibited much more adsorption and faster visible-light (wavelength >420 nm)-irradiated photocatalytic reduction of aqueous Cr(VI), as compared with SnS2 nanoparticles, nanoplates-assembled flowerlike hierarchical structure SnS2 synthesized by hydrothermal method, Fe, N and C tri-doped TiO2, and hydrothermally treated g-C3N4. The underlying reasons for the far superior performance of F-SnS2 were proposed, based on the comparison of the microstructure, specific surface area, optical, electrochemical impedance, photocurrent, surface charge, and Cr(VI) adsorption properties of F-SnS2 and SnS2 nanoparticles. Besides, the photocatalytic reusability and stability of F-SnS2, as well as the effects of photocatalytic testing parameters (including dosage of photocatalyst, initial pH and concentration of K2Cr2O7 aqueous solution) on the Cr(VI) removal efficiency by F-SnS2 were also studied. This work may advance our knowledge on the scalable low temperature solid phase synthesis of SnS2 nanomaterial, and contribute to the application of SnS2 in treating the Cr(VI)-polluted water.