Titania (titan dioxide) particles were produced by a sol-gel reaction of titan isopropoxide (TIP) with a variety of properties. Amorphous titania was obtained under the reaction conditions of the molar ratios of ultrapure water/TIP (in isopropanol) below stoichiometric ratios. A yellow solution was produced from the amorphous titania reacted with hydrogen peroxide, followed by conversion to a transparent yellow gel, from which thin films were obtainable. The gel was soluble in aqueous nitric acid to form a stable solution. The solution can be utilized to coatings. Some spectroscopic techniques, such as UV-VIS diffuse reflectance spectroscopy (DRS), IR DRS and Laser-Raman spectroscopy, were utilized to measure the surface properties of the particles and the thin films mentioned above. As a result, the reactivity was found to be related to the surface acidity of the amorphous particles, which was correlated to the optical gap value of the particles estimated from the leading edge of absorption in UV-VIS spectra. The solubility of titania thin films in aqueous nitric acid was also related to the optical gap value of the amorphous titania particles. The dissolution did not occur for rutile and anatase. © 1990.
