Preparation and characterization of TiO2/SiO2 aerogel microspheres

TiO2/SiO2 aerogel microspheres were prepared by using TiOSO4 and silica sols as raw materials, and formamide as a drying control chemical additive, which was used to improve the gel texture and the structure evolution. Wet gel microspheres were formed by sol-gel process in W/O emulsion, and then aged by a successively solvent exchanging of alcohol, tetraethylorthosilicate, (TEOS)/alcohol and alcohol at a certain temperature. The aged gel microspheres were dried at ambient pressure to obtain TiO2/SiO2 aerogel microspheres. The aerogel microsphere samples were characterized with optical microscope, SEM, TEM and BET techniques. The results show that the aerogel microsphere samples were comprised of dispersed TiO2, and SiO2 nanoparticles with sizes of about 15 nm. The density of the typical sample is 177 kg (.) m(-3), the specific surface area is 372 m(2) (.) g(-1) and the average pore size is 22.78 nm with porosity of 92.0%. By changing the preparation condition, the diameters of TiO2/SiO2 aerogel microspheres can be varied in the range of 10 mu m to 200 mu m, the densities in the range of 150-300 kg (.) m(-3), the specific surface areas in 300-400 m(2) (.) g(-1), and the average pore sizes in the range of 18.71-22.78 nm.