SiO2/TiO2 composite aerogels: Preparation via ambient pressure drying and photocatalytic performance

Silica/titania (SiO2/TiO2) (Si/Ti=1:1) composite aerogels have been manufactured via ambient pressure drying using tetraethoxysilane (TEOS) and tetrabutyl titanate (TBT) as precursors. Changes in the structure and the surface properties of the aerogels during the heat treatment were investigated in detail by N2 adsorption-desorption techniques, SEM, TEM, XRD, FTIR, and UV-vis absorption spectra. The results showed that the as obtained aerogel with a porous structure possessed a surface area of 667 m2/g, average pore size 3.4 nm, and pore volume 0.68 cm3/g. After calcination, the surface area decreased while the average pore size and the pore volume increased with the rise of heat treatment temperature. FTIR spectra showed the existence of Si-O-Ti in the aerogels and that after calcination at 800 °C, anatase nanoparticle appeared as demonstrated in XRD pattern. The photocatalytic performance was evaluated by degradation of MB and the results demonstrated that the aerogels calcined at 800 °C have a better photocatalytic activity than other samples.