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

Abstract 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 °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.