A general method for the synthesis of graphene oxide-metal sulfide composites with improved photocatalytic activities

A simple wet chemistry method was employed for the synthesis of graphene oxide-metal sulfide composites. The obtained products were characterized by X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, nitrogen absorption-desorption specific surface area and UV-Vis spectroscopy. The study indicates that sulfides nanorods were well dispersed on the graphene oxide nanosheets in the graphene oxide-metal sulfide composites. It was found that the specific surface area of the composites increased with the introduction of graphene oxide. The as-synthesized graphene oxide-metal sulfide composites were used as photocatalysts for the color removal of methyl orange under UV light irradiation. The results indicated that the graphene oxide-metal sulfide composites exhibited improved photocatalytic activity to pure sulfides and commericial sulfides, with nearly 95% and 90% of methyl orange degraded after irradiation for 15 min, respectively. The excellent photocatalytic activity of the composites can be ascribed to the high specific surface area and the reduction of photoinduced electron-hole pair recombination due to the introduction of graphene oxide. With the help of various radical scavengers, O2− and h+ were proved to be the main reactive species for the color removal of methyl orange.