SYNTHESIS AND CHARACTERIZATION OF TITANIA AEROGELS

Titania (TiO2) aerogels were prepared by the sol-gel synthesis of titanium n-butoxide in methanol and the subsequent removal of solvent with supercritical carbon dioxide. The water and nitric acid contents were varied in an attempt to maximize the surface area of the calcined sample. The resulting TiO2 aerogel, after calcination at 773 K for 2 h, had a BET surface area in excess of 200 m2/g, contained mesopores in the range 2-10 nm, and was of the pure anatase form. Nitrogen adsorption, X-ray diffraction, and laser Raman spectroscopy were used to characterize the physical properties of this sample as a function of heat treatment up to 1073 K. Titration with n-butylamine showed that this TiO2 aerogel was weakly acidic. Comparisons with a commercial sample, Degussa P-25, were made.