SnS2/SnO2 heterostructured nanosheet arrays grown on carbon cloth for efficient photocatalytic reduction of Cr(VI).

Nowadays, among the many heavy metal pollutants, hexavalent chromium (Cr(VI)) seriously threatens ecological systems and human health due to its high solubility, acute toxicity and potential carcinogenicity in wastewater. Meanwhile, semiconductor photocatalytic reduction is continuously gaining increasing significant research attention in the treatment of Cr(VI). Hence, we report an efficient preparation method for SnS2/SnO2 composites on carbon cloth (CC), for efficient photocatalytic reduction of aqueous Cr(VI). The morphology, composition, surface elements and optical properties of CC@SnS2/SnO2 composites were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and UV-vis diffuse reflectance spectroscopy. It was found that carbon cloth (CC) could be effectively used as a catalyst support in the obtained SnS2/SnO2 composites. In addition, the CC@SnS2 calcined 30 min exhibited the best efficiency for photocatalytic reduction of aqueous Cr(VI), which can be attributed to the formation of a heterostructure and the effective separation of photogenerated electrons (e-) and holes (h+). It was also found that acidic conditions are more favorable for the photocatalytic reduction of aqueous Cr(VI) due to the presence of abundant H+. The photocatalytic mechanism of as-prepared composites is also discussed in detail.