Effects of Heat Treatment Temperature on Photocatalytic Activity of TiO2/SiO2 Composite Aerogels

TiO2/SiO2 composite aerogels were prepared by Sol-Gel method at ambient pressure and heat-treated at different temperatures. The microstructure of TiO2/SiO2 composite aerogels was characterized by X-ray diffraction (XRD), thermo gravimetric analyzer (TGA) and N2 adsorption-desorption. The photocatalytic activity was evaluated by means of photocatalytic degradation of methyl orange under UV irradiation. The effects of heat treatment temperatures on microstructure and photocatalytic activity were investigated. With the increase of heat treatment temperature, the crystallization of anatase and the anatase grain size increase, however, the specific surface area decreases. As a result, the photocatalytic activity of TiO2/SiO2 composite aerogels is enhanced initially, then decreases with the increase of heat treatment temperature. When the heat treatment temperature is set at about 700 the degradation ratio of methyl orange on the TiO2/SiO2 composite aerogels reaches 95.4% after irradiated by ultraviolet light for 20 min.