Effects of Silicon Content on Microstructure and Photocatalytic Activity of TiO_2/SiO_2 Composite Aerogels

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 com-posite 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%.