SOL-GEL DERIVED ANATASE TIO2 - MORPHOLOGY AND PHOTOACTIVITY

High-surface area TiO2 (anatase) was prepared by the sol-gel method an d characterized by various instrumental and analytical methods, includ ing X-ray diffraction, thermogravimetric analysis, infrared spectrosco py, porosimetry, specific surface area measurements, scanning electron microscopy, and titration of surface hydroxyl groups. The specimen wa s tested for photodegradation of phenol and nitrophenols carried out i n aqueous suspension at pH=3; photoactivity was compared with that of commercially available anatase TiO2. Results are discussed in terms of porosity, surface area, and availability and population of surface OH groups, consequent upon the particular method used for preparation. T he observed partial deactivation in time of gel-derived anatase was st udied, and almost complete restoration of photoactivity after thermal treatment at 573 K for 3 hours was observed.