In Situ Synthesis of Conjugated Polyvinyl Alcohol Derivative-Modified SnS₂ Nanosheets with Improved Visible Photocatalytic Reduction of Cr(VI)

The development of high-performance photocatalysts is crucial in addressing water environmental pollution using photocatalytic technology. In this study, CPVA/SnS₂ heterojunctions modified with conjugated polyvinyl alcohol were prepared using water-soluble polyvinyl alcohol. The effects of temperature and CPVA loading amount on the chemical composition, morphology, optical and electrochemical properties, and visible-light photocatalytic reduction of aqueous Cr(VI) performance of CPVA/SnS₂ were evaluated. The results showed that the CPVA was uniformly coated on the surface of SnS₂, improving the light absorption range and the effective utilization of photogenerated carriers. All CPVA/SnS₂ heterojunctions exhibited enhanced photocatalytic activity compared to bare SnS₂. The reaction rate for the photocatalytic reduction of Cr(VI) by CPVA/SnS₂-B (0.034 min⁻¹) was 3.46 times higher than that of SnS₂ (0.0098 min⁻¹). The photocatalytic mechanism of S-scheme heterojunction for the photocatalytic reduction of Cr(VI) by CPVA/SnS₂ was proposed based on the trapping experiments and electrochemical results. This study provides a straightforward strategy for the construction of efficient photocatalysts.