N-doped sites modulate Ag/TiO2 interaction for improved photocatalytic degradation of tetracycline

The weak interactions between Ag/TiO2 composite materials have been a major obstacle to improving the photocatalytic degradation activity of tetracycline (TC). Accordingly, this study prepared Ag/TiO2 with N interstitial doping (Ni) and substitutional doping (Ns), elucidated the mechanism of doping sites and investigated the photocatalytic activity of catalysts for TC degradation. The findings demonstrated that the degradation efficiency of Ag/Ns-TiO2 reached 90 % following 60 min of visible light irradiation. Analysis shows that substitutional doping increases the content of surface oxygen vacancies and the number of electron transfers in Ag/ TiO2. However, the impurity level generated in Ag/Ni-TiO2 impedes charge separation, thereby resulting in activity even lower than unmodified Ag/TiO2. Further antibacterial experiments were conducted to broaden the application scope of the catalyst, and Ag/Ns-TiO2 also has the best performance among all catalysts.