Role of surface ligands on CdSe/CdS QDs in affecting the charge separation and photocatalytic behavior in reducing the graphene oxide

Abstract

In this paper, the photocatalytic behavior of CdSe/CdS quantum dots (QDs) in reducing the graphene oxide (GO) with different surface ligands was investigated. Here, three surface ligands of different functional groups (oleic acid, poly (acrylic acid polymers) and S2−) were selected to study the influence of surface ligands on photocatalytic behavior of the CdSe/CdS QDs. Meanwhile, the obtained samples can be used as photocatalyst, and the photocatalytic activity was evaluated by photodegrading a methylene blue solution. It turned out that the QDs–S2−–GO sample showed the highest photocatalytic activity under visible-light irradiation. Different surface ligand has different influence on the charge separation efficiency, which has different influence on photocatalytic behavior. The results show that the photocatalytic behavior is highly dependent on the electron attracting ability of the surface ligands on the CdSe/CdS QDs. Finally, a possible photocatalytic mechanism is proposed.