Flame-assisted combustion preparation of highly efficient black TiO2 microspheres photocatalysts under visible light

Black TiO 2 microspheres photocatalysts with high light absorption intensity and photosensitive activity were prepared by a simple two-step method of flame-assisted combustion hydrolysis of tetrabutylorthotitanate (TBOT) and NaBH 4 reduction. The black TiO 2 microspheres photocatalysts were characterized by XRD, TEM, XPS, EELS , and UV-Vis absorption spectroscopy . The results show that the reduced TiO 2 exhibits a unique core-shell composite structure with a large number of oxygen vacancies and defects in the outer layer due to Ti 3+ , which effectively reduces the band gap of the photocatalyst. Compared with the commercial P25 catalyst, B-TiO 2 (1:7) showed higher removal of carbamazepine (CBZ) under visible light and its photocatalytic activity was 1.7 times higher than that of P25. This high photocatalytic activity is due to the efficient separation of electron-hole pairs, creating a greater number of active species. B-TiO 2 (1:7) maintained high activity after five repeated cycles and achieved 89.7 % removal of CBZ.