Mesoporous SiO2-Modified Nanocrystalline TiO2 with High Anatase Thermal Stability and Large Surface Area as Efficient Photocatalyst

Abstract

Mesoporous SiO2-modified nanocrystalline TiO2 photocatalysts have been prepared by sol-hydrothermal processes, followed by post-treatment with appropriate amount of surfactant F127-modified silica sol. The resulting photocatalysts were also characterized by X-ray diffraction, Raman spectroscopy, Brunauer−Emmett−Teller spectroscopy, N2 adsorption−desorption, transmission electron microscopy, FT-IR, X-ray photoelectron spectroscopy, UV−vis diffuse reflectance spectroscopy, steady state surface photovoltage (SS-SPV), and transient state surface photovoltage (TS-SPV) techniques. The photocatalytic activities of the samples were evaluated by degrading rhodamine B solution under simulated solar illumination. The results show that the surface modification with mesoporous SiO2 greatly enhances the thermal stability of the nanocrystalline anatase TiO2, even still being with a main anatase phase after calcination at 900 °C, and the more is the amount of SiO2 used, the more obvious is the ehancement in the thermal s...