Linker gadolinium as charge channel and singlet oxygen activation site in graphitic carbon nitride for enhancing photocatalytic decomposition of tetracycline

Reactive oxygen species are essential in photocatalytic water treatment. In this paper, Gd doped carbon nitride (CN) photocatalysts were prepared by simple thermal polymerization for the photocatalytic degradation of tetracycline under visible light irradiation. The photodegradation rate of 1.0GdCN is as high as 95% in 18 min, and the photocatalytic performance is much higher than that of CN. The improvement of photocatalytic performance is mainly attributed to the fact that Gd ion implantation directly provides active sites for oxygen activation and induces the formation of N vacancies. The results of characterizations show that the introduction of Gd in CN can improve the conversion ability of activated oxygen, carrier separation and energy band structure adjustment. Therefore, 1.0GdCN photocatalyst can be employed for efficient photocatalytic synthesis of tetracycline. Furthermore, three ways of photocatalytic degradation of tetracycline were revealed by high performance liquid chromatography-mass spectrometry. This work provides insights into the doping strategy of CN to improve the production of reactive oxygen species for environmental remediation.