Surface hydroxylation of TiO2/g-C3N4 photocatalyst for photo-Fenton degradation of tetracycline

Abstract

The photocatalytic degradation of tetracycline in aqueous solution is a typical heterogeneous reaction, and thus the design of efficient photocatalysts for tetracycline degradation should revolve the process features of heterogeneous reaction closely. In the present work, TiO 2 -P/ g -C 3 N 4 composites with abundant surface hydroxyls were prepared by coupled g -C 3 N 4 nanosheets with plasma treated TiO 2 (TiO 2 -P) nanoparticles. The resultant TiO 2 -P/ g -C 3 N 4 as photocatalysts showed higher activity for the degradation of tetracycline in aqueous solution than g -C 3 N 4 , TiO 2 , TiO 2 -P and TiO 2 / g -C 3 N 4 under visible light irradiation. The better activity of TiO 2 -P/ g -C 3 N 4 photocatalysts for tetracycline degradation could be ascribed to the good synergy between TiO 2 -P and g -C 3 N 4 . Specifically, due to the presence of surface hydroxyls on TiO 2 -P, the tetracycline adsorption activity, electrons-holes separation property as well as H 2 O 2 activating activity of TiO 2 -P/ g -C 3 N 4 during tetracycline degradation were improved. By integrating the property of g-C 3 N 4 photocatalyst in H 2 O 2 production, as well as the property of TiO 2 -P in activating H 2 O 2 into •OH and •O 2 - , efficient photo-Fenton degradation of tetracycline was achieved in the TiO 2 -P/ g -C 3 N 4 photocatalytic system. Our study on TiO 2 / g -C 3 N 4 composite photocatalyst provides helpful inspiration to design photocatalysts with high-activity for the photo-Fenton degradation of organic pollutants.