Graphene quantum dots-decorated ZnS nanobelts with highly efficient photocatalytic performances

Hybrid nanostructures combining inorganic materials and graphene have shown great potential for the environmentally friendly treatment of effluents. Herein, graphene quantum dots (GQDs)-decorated ZnS nanobelts have been synthesized via a facile hydrothermal method. The electrostatic attraction of two materials and the thermal reduction of graphene are the main driving forces to fabricate well-defined composite nanostructures. GQDs in GQD/ZnS nanocomposites have been found to exist discretely and uniformly on the surfaces of ZnS nanobelts. The photocatalytic activity of GQD/ZnS nanocomposites has been found to be highest at a GQD/ZnS mass ratio of 8 x 10(-4). The photocatalytic rate constant (0.0046 min(-1)) of GQD/ZnS nanocomposites having the optimized GQD content in the photodegradation reaction of rhodamine B has been found to be 14 times higher than that of commercially available ZnS powder. Decorated GQDs introduce an additional visible-light response and serve as electron collectors and transporters to block electron-hole recombination efficiently, enhancing the photocatalytic performances of ZnS nanobelts immensely.