Preparation of nanometer titanium oxide with n-butanol supercritical drying

n-Butanol supercritical drying technique was developed to prepare nanometer particles. The procedure mainly consisted of sol preparation, filtering as well as washing, replacement of water in the precipitate with n-butanol and supercritical drying. Anatase and rutile mixture with a particle size of 10-20 nm, a surface area of 166.8 m(2)/g and a pore volume of 1.286 ml/g was obtained using the preparation technique. No marked coagulation was caused by the effect of water-n-butanol interface tension in the thermal treatment to replace water in the precipitate with n-butanol. Ethanol supercritical drying also gave anatase titanium oxide. The thermal treatment during the preparation of both ethanol and n-butanol supercritical drying resulted in evident growth of crystal. (C) 1999 Elsevier Science S.A. All rights reserved.