Fabrication of 2D graphene oxide incorporating S-scheme Sn2S3–In2S3 heterojunctions for enhanced photocatalytic mineralization of organic pollutants

Abstract

Harnessing solar energy using semiconductor-based materials to generate charge pairs to effectively drive photo-redox reactions has been envisioned as a promising approach toward a sustainable future. In this arena, the metal sulfide nanoparticles have demonstrated excellent performance in photomineralizing colored matter. However, their small surface area and relatively slow charge transfer has limited their practical applications. Therefore, for the effective mineralization of colored matter, we devise and construct the Sn₂S₃–In₂S₃ S-scheme in collaboration with 2D graphene oxide nanosheets. The material offers a well-defined nanosheet and nanoflake morphology for the effective contact with and catalysis of crystal violet (CV) dye as a model contaminant. Compared to Sn₂S₃–In₂S₃/GO, the pristine Sn₂S₃ and Sn₂S₃–In₂S₃ cause negligible degradation of CV using a visible-light source. This enhanced photocatalysis is supported by the peculiar properties of GO, such as its high surface area, electron-shuttling performance, and ability to prevent charge back-recombination. Under simulated conditions, more than 99% of CV was mineralized within 60 min of contact time. The photodegradation follows pseudo-first-order kinetics with a rate constant (K_t) = 0.02317 min⁻¹. Furthermore, the photo mineralization of CV dye was thoroughly investigated using the GC-MS technique. More importantly, Sn₂S₃–In₂S₃/GO exhibits promising recyclability over multiple degradation cycles.