Preparation and characterization of graphitic C₃N₄/Ag₃VO₄ with excellent photocatalytic performance under visible light irradiation

The graphitic C₃N₄ was modified by barbituric acid and denoted as BA-C₃N₄. Then, the BA-C₃N₄/Ag₃VO₄ composites with different contents of BA-C₃N₄ were prepared by codeposition-precipitation method. The specific surface areas of the composites were investigated via nitrogen absorption–desorption isotherms. The results show that after adding BA-C₃N₄ into Ag₃VO₄, the surface areas of the composites have been enlarged obviously. The photocatalytic performance of composites compared with that of BA-C₃N₄ and Ag₃VO₄ is effectively improved. The sample 30 wt% BA-C₃N₄/Ag₃VO₄ has the best photocatalytic activity, whose kinetic constant is seven times larger than that of both pure BA-C₃N₄ and Ag₃VO₄. The photocatalytic mechanism is proposed on the basis of active species trapping experiments in photocatalytic degradation process. It is suggested that the enhanced photocatalytic activity of composites is mainly attributed to the enlarged surface area and the heterojunction between BA-C₃N₄ and Ag₃VO₄, leading to an effective separation of the photoinduced electron–hole pairs.