Facile preparation of 2D sandwich-like CdS nanoparticles/nitrogen-doped reduced graphene oxide hybrid nanosheets with enhanced photoelectrochemical properties

A facile surface-layer-absorption strategy was successfully integrated via a simple in situ sulfidation reaction route for the deposition of CdS nanoparticles on N-doped reduce graphene oxide (N-rGO) nanosheets to produce 2D sandwich-like CdS/N-rGO hybrid nanosheets (HNs). The successful doping of N in the rGO nanosheets and the sandwich stuffing of CdS nanocrystals in the N-rGO sheets were revealed using a variety of techniques, including XPS, XRD and TEM. Compared to the pure CdS and CdS/rGO samples, the as-prepared sandwich CdS/N-rGO HNs exhibited a significantly enhanced photoelectrochemical current response and improved photocatalytic activity for the reduction of aqueous Cr(vi) and the photodegradation of rhodamine B (RhB) under visible-light irradiation. Owing to nitrogen doping in the carbon network of graphene and the unique combination of the CdS nanocrystals and N-rGO nanosheets, superior electrical conductivity could be obtained with the N-rGO matrix. This led to improved charge separation and transport of the photoinduced carriers from the CdS nanoparticles as well as enhanced photochemical performance, which was confirmed by transient photocurrent and electrochemical impedance spectroscopy (EIS).