One-pot synthesis of ZnS-rGO nanocomposites using single-source molecular precursor for photodegradation of methylene blue and reduction towards toxic Cr(VI) under solar light

A simple approach is described for the preparation of zinc sulfide-reduced graphene oxide (ZnS-rGO) nanocomposites using a single-source molecular precursor. The Zinc(II) benzaldehyde thiosemicarbazone complex has been used as a single-source molecular precursor to attain desired zinc and sulfur stoichiometry in the coexistence of graphene oxide, using a solvothermal method. Zinc metal chalcogenalato complex and nanocomposites were characterized using various techniques. The ZnS-rGO nanocomposites were used for the chemical reduction of highly toxic Cr(VI) to non toxic Cr(III) state in the presence of formic acid as a reducing agent. The reduction of hexavalent to trivalent chromium is carried out at room temperature using natural sunlight within 80 min. Furthermore, these zinc sulfide-reduced graphene oxide nanocomposites exhibit enhanced photocatalytic degradation efficiency toward methylene blue (MB) dye using solar light irradiation.