Rapid microwave-assisted synthesis of graphene nanosheets–zinc sulfide nanocomposites: Optical and photocatalytic properties

A facile and efficient strategy for preparing graphene nanosheets–zinc sulfide (GNS–ZnS) nanocomposites assisted by microwave irradiation for the first time is demonstrated. This process involved the reaction of graphene oxide nanosheets as a dispersant and two-dimensional growth template for ZnS nanoballs, zinc acetate as a zinc source, and thioacetamide (TAA) as a sulfide source as well as a reducing agent, resulting in the in situ formation of ZnS nanoballs with an average diameter of 41.9 nm supported on graphene oxide nanosheets and simultaneous reduction of graphene oxide nanosheets to graphene nanosheets. It has been found that the ZnS nanoballs are composed of many small self-assembled ZnS crystals (subunits) with an average size of 3 nm. Photoluminescence measurements show that there is photoinduced electron transfer between ZnS and GNS. Furthermore, the as-prepared graphene-based nanocomposites show an excellent photocatalytic activity toward the photodegradation of methylene blue. The detailed formation and photocatalytic mechanism are also provided here.