Synthesis of high-temperature resistant monolithic zirconia-based aerogel via facile water glass assisted sol–gel method

Zirconia aerogel monolith was prepared by a facile co-hydrolysis method, which adopts ZrOCl2 as the precursor and water glass (Na2SiO3) as the gel initiator. ZrO2 aerogel was formed by rational controlling of the hydrolysis rate of Zr4+ ions by Na2SiO3. The obtained aerogel consists of ZrO2 nanoparticles surrounded by amorphous SiO2 nano shell. The density and the surface area can be well tuned by adjusting the ratio of ZrOCl2 to Na2SiO3. The in-situ introduced SiO2 nano shell layer acts as the particle boundary reinforcement phase, which not only strengths the ZrO2 particle connections to form monolith, but also significantly mitigates the sintering of ZrO2 nanoparticles at high temperature. As a result, the zirconia aerogel prepared by such method could maintain its nanoporous microstructure up to 1000 °C.