Preparation of SiO2-TiO2 Aerogels Using Supercritical Impregnation

The preparation of SiO2-TiO2 aerogels by supercritical impregnation of titanium alkoxides into silica alcogels was investigated. A mixture of CO2 and 2-propanol with dissolved titanium tetraisopropoxide modified with acetylacetone was used as the impregnation medium. Prior to the experiments, the supercritical behaviour of the impregnation solution was investigated. The microstructure and properties of aerogels prepared by the supercritical impregnation method were almost identical to those generated by the liquid impregnation. However, the time for impregnation was substantially decreased and the homogeneity of the impregnated titanium distribution on the aerogel increased.