Microstructural characterization and properties of ambient-dried SiO2 matrix aerogel doped with opacified TiO2 powder

Hydrophobic silica-based aerogels with different nano-TiO2 additive were successfully synthesized by an ambient pressure drying method. After aging and washing of wet gel, surface modification with cyclohexane was followed to replace the solvent with the pores of wet gel to reduce the surface tension during ambient drying. The synthesized SiO2-TiO2 aerogels thermally treated at 350 °C were light and crack-free, and the density was 0.125-0.138 g/cm3. The microstructure and physical characteristic of the SiO2-TiO2 aerogels were characterized by FTIR, SEM, EDS and BET. Their specific surface was in the range of 785-1210 m2/g and their average pore size was between 30 and 45 nm. Nano-TiO2 powders are physically embedded by SiO2 aerogel, and there is an obvious Ti-O-Ti and Si-O-Si bonding group based on structural analysis.