Structure and phase composition of titania aerogels can be substantially influenced simply by the process of drying their parent water colloid suspensions prepared by the reaction of hydrogen peroxide with suspension of precipitates obtained by neutralization of solution of titanyl sulfate with ammonia. Two methods of drying are compared: (1) lyophilization of fast frozen material immersed in liquid nitrogen, and (2) critical point drying using supercritical CO2 under high pressure. Both methods of drying lead to yellow titanium peroxide aerogels consisting of nanometer-sized blocks. While lyophilization leads to foils consisting of nano-sized crystalline nuclei of peroxo-polytitanic acid dispersed in predominantly amorphous material, the critical point drying provides rather bulk highly porous composite consisting of randomly oriented flat nanoparticles (5–10 nm) composed of crystalline anatase and amorphous peroxo-polytitanic acid.

Subrt J., Plizingrova E., Palkovska M., Bohacek J., Klementova M., Kupcik J., Bezdicka P., Sovova H.: „Titania aerogels with tailored nano and microstructure: comparison of lyophilization and supercritical drying“, Pure Appl. Chem., 89(4) (2017) 501-509. UACH (WP7) IF: 2,626. DOI: https://doi.org/10.1515/pac-2016-1031