关键词: TiO₂/SiO₂复合气凝胶, Si含量, 组织结构, 光催化性能

Abstract:

TiO₂/SiO₂ composite aerogels with different silicon contents were prepared by Sol-Gel method. The microstructure of TiO₂/SiO₂ composite aerogels was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscope (FTIR), X-ray photoelectron spectroscope (XPS) and N₂ adsorption-desorption, the photocatalytic activity was evaluated by means of photocatalytic degradation of methyl orange under UV irradiation. The effects of silicon content on microstructure and photocatalytic activity were investigated. The results show that Ti-O-Ti bonds, Si-O-Si bonds and Ti-O-Si bonds all form in TiO₂/SiO₂ composite aerogels, which make composite aerogels have smaller crystal size, higher specific surface area and better thermal stability. As the silicon content increases, the specific surface area increases, however the anatase grain size, the anatase content and the average pore diameter reduce. At higher silicon content level, the photocatalytic activity of composite aerogels for methyl orange is improved initially, then decreases with the increase of silicon content. Proper silicon content can refine the structure and improve photocatalytic activity of TiO₂/SiO₂ composite aerogels dramatically, and the optimal silicon content is about 9wt%.

Key words: TiO₂/SiO₂ composite aerogels, silicon content, microstructure, photocatalytic activity