Ultrafine titania by flame spray pyrolysis of a titanatrane complex

Ultrafine titania particles can be produced by flame spray pyrolysis of a chelated metal alkoxide. The precursor can be made by reacting a titanium hydrosol with triethanolamine in ethylene glycol. The chelate, dissolved in ethanol, is misted as an aerosol into an oxidizing flame where it undergoes combustion. The combustion process generates particles, probably by a gas phase condensation process, that are discrete single crystals that exhibit some faceting. The powder is a mixture of anatase and rutile (<10%), with a 45 +/- 5m(2)g(-1) BET surface area. The calculated equivalent spherical diameter (34 + 4nm) is consistent with typical particle sizes found in TEM micrographs. The particles are briefly compared with commercial ultrafine particles produced by flame hydrolysis of TiCl4 and by Ti vapor condensation. (C) 1998 Elsevier Science Limited.