An improvement on sol-gel method for preparing ultrafine and crystallized titania powder

TiO2 nanoparticles were prepared using a sol-gel method with inorganotitanates and polyethylene glycol (PEG). However, the way TiO2 particles were obtained from the dry gel was not by calcining but by redissolving the dry gel which had been treated at 100 degrees C, thereby releasing the particles. The TiO2 powder prepared in this manner was ultra-fine (similar to 4 nm) and crystallized (anatase phase) merely by being exposed to 100 degrees C while inside the gel. It was supposed that this low temperature crystallization of TiO2 results from the special structure of the gel which formed through the linking of TiO(NO3)(2). H2O with PEG chains by a hydrogen bond. This preparation method also has an advantage in environmental protection. (C) 2000 Elsevier Science S.A. All rights reserved.