Microstructural characterization and properties of ambient-dried SiO_2 matrix aerogel doped with opacified TiO_2 powder

摘要

Hydrophobic silica-based aerogels with different nano-TiO_2 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 SiO_2-TiO_2 aerogels thermally treated at 350 deg C were light and crack-free, and the density was 0.125-0.138 g/cm~3. The microstructure and physical characteristic of the SiO_2-TiO_2 aerogels were characterized by FTIR, SEM, EDS and BET. Their specific surface was in the range of 785-1210 m~2/g and their average pore size was between 30 and 45 nm. Nano-TiO_2 powders are physically embedded by SiO_2 aerogel, and there is an obvious Ti-O-Ti and Si-O-Si bonding group based on structural analysis.