Synthesis of a visible light driven Ag–CeO2/g-C3N5 heterojunction with efficient photocatalytic performance for organic dyes

Wastewater containing organic dyes is harmful to the ecological environment and human health. Graphitic carbon nitride (g-C3N5) is suitable for the photocatalytic degradation of organic dyes, but its photocatalytic activity is low due to several drawbacks. A series of Ag–CeO2/g-C3N5 composites with different morphologies of Ag–CeO2 have been prepared in order to improve the photocatalytic activity of g-C3N5. The photocatalytic activities of the Ag–CeO2/g-C3N5 composites were investigated using rhodamine B (RhB) as the target pollutant. When compared with Ag–CeO2 spheres and g-C3N5, the charge separation efficiency and photocatalytic activity of the Ag–CeO2/g-C3N5 heterostructure were significantly improved. The photodegradation rate of RhB using 50 wt% Ag (1.50)-CeO2(sphere)/g-C3N5 was 96.5 %, while pure g-C3N5 and Ag (1.50)-CeO2 spheres was 30.8 and 9.9 %, respectively. This was attributed to the synergistic effect of the heterojunction comprised of Ag, CeO2, and g-C3N5. As an electronic medium, Ag transfers electrons between g-C3N5 and CeO2, which can promote electron-hole separation and improve the photocatalytic activity. The 50 wt% Ag (1.50)-CeO2(sphere)/g-C3N5 composites also had fair photocatalytic stability and ·O2− plays a dominant role in the RhB photodegradation process. In addition, the photocatalytic mechanism of 50 wt% Ag (1.50)-CeO2(sphere)/g-C3N5 has also been described.