Abstract: TiO₂/SiO₂ aerogels, a special kind of mesoporous materials, is comprised of linked nano-sized pores which possess a high photocatalytic activity. In our work, sols of TiO₂ and SiO₂ were prepared separately and mixed to prepare TiO₂/SiO₂ gels. Formamide as the drying control chemical additive(DCCA) was added to stiffen the microstructure of TiO₂/SiO₂ gels. TiO₂/SiO₂ gels were immersed in the tetraethoxysilane/ethanol solutions, exchanged pore fluid with low surface tension solvent, aged and then dried in different stages to realize the preparation of TiO₂/SiO₂ aerogels by non-supercritical drying. The resultant aerogels were transparent or translucent, highly porous and low density foams with bulk densities in the range of 0.4—0.9 g/cm³ and porosity about 80%—95%. The TiO₂/SiO₂ aerogels were comprised of dispersed TiO₂ and SiO₂ particles. The average particle diameter is about 10 nm, and average pore diameter is tens of nanometers. The phase of SiO₂ is amorphous and TiO₂ remains anatase microcrystal until 800 ℃. The effects of molar ratio of TiO₂ to SiO₂ and amount of formamide on sol-gel process and aerogel properties were also discussed.

Key words: TiO2/SiO2 aerogels, Non-supercritical drying, Preparation, Formamide