ZnS-rGO nanocomposite: an efficient sun light driven photocatalyst for degradation of methylene blue

The zinc sulphide-reduce graphite oxide (ZnS-rGO) nanocomposite has been synthesized solvothermally and explored for its potential applications in photocatalysis for dye degradation. The combination of ZnS and reduced graphene oxide (rGO) in a composite structure result in enhanced photocatalytic properties. The rGO acts as a support for ZnS nanoparticles, which enhances the surface area as well as the photocatalytic performance. The presence of rGO also helps prevent the agglomeration of ZnS particles. The ZnS-rGO nanocomposite samples were characterised by X-ray diffraction, FTIR, and FESEM. The elemental analysis was carried out by EDS. The two types of samples, ZnS-rGO-A (0.5 wt% of rGO) and ZnS-rGO-B (0.75 wt% of rGO) were synthesized with different concentrations of ZnCl2 and tested their photocatalytic performances for comparative study. The ZnS-rGO nanocomposite showed superior photocatalytic activity as compared to pristine ZnS. The ZnS-rGO exhibits improved photocatalytic activity owing to the harmonious effect of its individual components (73% degradation in 120 min). ZnS is a semiconductor material that can efficiently absorb UV light, whereas ZnS-rGO absorbs light into visible region and generate highly reactive oxygen species that can degrade organic dyes. On the other hand, rGO possesses large surface area with good electrical conductivity, which can facilitate the transfer of photo-generated excitons and provide active spots for the adsorption and degradation of organic dyes.