Graphene-CdS composites with visible-light photocatalytic activity in degrading methylene blue

This paper reports a facile method for the preparation of graphene-based composite materials consisting of reduced graphene oxide (RGO) and CdS nanoparticles. Both CdS and the RGO-CdS composite were prepared in aqueous medium and without the use of obnoxious organic solvent. The synthetic method was based on the reduction of graphene oxide (GO) by photoexcited electrons from semiconductor CdS. The RGO with a high charge mobility served as a rigid support for the CdS particles, while the CdS particles on the other hand played a role of preventing the RGO sheets from aggregations. The RGO-CdS composites displayed a higher photocatalytic activity towards degrading of methylene blue (MB) under visible light as compared to pristine CdS because of the enhanced adsorption of MB on the RGO sheets and retarded electron-hole recombination rate