Thermally stable SiO 2-doped mesoporous anatase TiO 2 with large surface area and excellent photocatalytic activity

Abstract

A thermally stable SiO 2-doped mesoporous TiO 2 with high crystallinity was prepared by a templating method. The content of SiO 2 dopant was varied from 3% to 20%. The gels were characterized by TG-DTA analysis. And the resultant catalysts were investigated by various physicochemical techniques, such as WAXRD, Raman spectroscopy, N 2 adsorption–desorption, TEM, FT-IR, and XPS. The WAXRD, TEM, and Raman measurements suggest that the SiO 2 dopant can enhance the thermal stability of the anatase phase remarkably. Rutile phase did not present at all even at 1000 °C when the SiO 2 content was up to 15%. N 2 adsorption–desorption results show that the SiO 2-doped samples have uniform pore diameters and large specific surface area, which is beneficial for photocatalytic reaction. The photocatalytic activities of the samples were evaluated by degradation of Rhodamin-6G solution under UV irradiation. The results show that the SiO 2-doped mesoporous TiO 2 have better activity than commercial P25. Especially, the 15% SiO 2-doped mesoporous TiO 2 exhibited much higher photocatalytic activity than P25 in a large range of calcination temperatures, even at 900 °C. The excellent photocatalytic activity of the samples can be attributed to the high anatase crystallinity, large specific surface area, preserved surface hydroxyl groups and mesoporous channels.