Controlled fabrication and photocatalytic properties of a three-dimensional ZnO nanowire/reduced graphene oxide/CdS heterostructure on carbon cloth.

A novel ZnO/reduced graphene oxide (RGO)/CdS heterostructure was successfully synthesized via a facile three-step solution method. RGO serves as an interlayer between ZnO nanowires and CdS quantum dots (QDs), which provides a high speed charge transfer channel, leading to an enhanced charge separation efficiency. Under UV light irradiation, the photocatalytic activity of the ZnO/RGO/CdS heterostructure is 4.0 times and 1.9 times as high as those of pure ZnO and ZnO/RGO, respectively. Under visible light irradiation, the ZnO/RGO/CdS heterostructure shows a dramatic visible light photocatalytic activity which is 2.3 times higher than that of the ZnO/CdS photocatalyst. The photocurrent of the ZnO/RGO/CdS heterostructure under UV light irradiation was greatly enhanced and a photocurrent under visible light irradiation was observed. The enhanced photocatalytic activity and the extended light adsorption spectrum originate from the type-II ZnO/CdS band alignment and the introduction of RGO as a charge mediator. Our results might open up a promising way to develop novel and highly efficient RGO-based heterostructure photocatalysts.