Highly thermally stable zirconia/silica composite aerogels prepared by supercritical deposition

Highly thermally stable zirconia/silica composite aerogels are prepared via a supercritical deposition method, which involves the deposition by zirconium alkoxide and partially hydrolyzed alkoxysilane during high-temperature ethanol supercritical fluid drying. The zirconia crystal growth and phase transition of the composite aerogels upon heat treatment are effectively inhibited by supercritical deposition, which significantly enhances the thermal stability of the aerogels. The resultant zirconia/silica composite aerogels exhibit a high specific surface area of 172 m2/g and a large pore volume of 0.97 cm3/g after heat treatment at 1000 °C. The resultant materials are promising candidates as high-temperature catalysts, catalyst supports, thermal insulators, etc.