High-efficiency visible light photocatalytic performances of the CdS(HS)/g-C3N4 composites: the role of intimate connection and hollow structure

The CdS(HS)/g-C3N4 photocatalysts with an intimate connection was successfully synthesized by a facile deposition method. The CdS hollow microspheres (CdS(HS)) were well anchored on the surface of g-C3N4 to form an intimate connection by the hydrogen bonding between g-C3N4 and CdS(HS). The structures, morphologies, optical and electrical properties and photocatalytic performance of samples were successfully characterized by multiple means. The CdS(HS)/g-C3N4 composites exhibited excellent photocatalytic activity and stability for the photodegradation of RhB, and the degradation rate constant of CdS(HS)/g-C3N4 with optimum CdS(HS) mass ratio of 0.25% was about 2.1 times higher than that of the pure g-C3N4 under the visible light irradiation for 20min. After four cycles, the CdS(HS)(0.25%)/g-C3N4 composite still maintained the high photocatalytic activity with the RhB degradation efficiency of 95%. Surprisingly, the photocorrosion of CdS(HS) caused by the photogenerated holes was inhibited effectively. The improvement of these properties should be ascribed to the intimate connection between g-C3N4 and CdS(HS) and the hollow structure of CdS(HS). The photocatalytic mechanism was also analyzed systematically. Furthermore, it was of great interest that the CdS(HS)/g-C3N4 composites possessed an excellent sedimentation property and they can be easily separated from the solution, which will be propitious to practical application.