TiO2-Based photocatalyst modified with a covalent triazine-based framework organocatalyst for carbamazepine photodegradation

Abstract

A novel fluorine-doped TiO₂ (TiO_2−XF_X) heterojunction semiconductor photocatalyst was synthesised using covalent triazine-based frameworks (CTFs) at different weight ratios. X-ray photoelectron spectroscopy revealed that doping with CTFs shifts the value of the TiO_2−XF_X catalyst to a lower binding energy, which led to the bandgap narrowing. From the results of the photocatalytic activity and Fourier-transform infrared spectroscopy, a rise in carbamazepine (CBZ) adsorption under dark conditions and an increased intensity of characteristic triazine units after exfoliation were observed, which indicated that the addition of nanosheet CTFs would increase the number of active sites. Furthermore, the results showed that the TiO_2−XF_X/CTFs photocatalyst was almost 5.5 times better than pure TiO_2−XF_X in the removal of CBZ under visible light owing to the narrowed bandgap, the increased active sites, the quick separation of photo-generated carriers, and improved light absorption. A mechanism for photodegradation of CBZ with the TiO_2−XF_X/CTFs photocatalyst was proposed.