Nitrogen-doping coupled with cerium oxide loading co-modified graphitic carbon nitride for highly enhanced...

The increasingly serious pollution of antibiotics brings an enormous threat to the ecological environment and human health. Graphite phase carbon nitride (g-C₃N₄), as a popular photocatalytic material, is widely used in photocatalytic degradation of antibiotics in water. In order to make up for the shortage of g-C₃N₄ monomer, CeO₂/N-doped g-C₃N₄ (CeNCN) composite photocatalysts co-modified with nitrogen doping and CeO₂ loading were designed and synthesized with the idea of expanding visible light absorption and promoting photogenerated carrier separation. CeNCN exhibits excellent photodegradation performance, the removal rate of tetracycline reached 80.09% within 60 min, which is much higher than that of g-C₃N₄ (CN) and N-doped g-C₃N₄ (NCN); and the quasi-first-order degradation rate constant is 0.0291, which is 7.86 and 2.29 times higher than CN and NCN. Electron spin resonance and free radical trapping experiments confirmed that h⁺, O₂^- and OH are the active substances in the photocatalytic system. After 5 cycles, the degradation efficiency of tetracycline still exceeds 75%, which indicates that CeNCN has good stability. This work proves that N-doping and CeO₂ loading can effectively broaden the photoresponse range of g-C₃N₄, facilitate the separation of photogenerated electron-hole pairs, and provide a reference for the construction of g-C₃N₄-based photocatalyst with high-efficiency photodegradation activity.