Preparation of nanocrystalline titania powder via aerosol pyrolysis of titanium tetrabutoxide

Nanocrystalline titanium dioxide was prepared via aerosol pyrolysis of tita nium alkoxide precursor at 200-580 degrees C in air and in nitrogen atmosph eres. Powders were characterized by x-ray diffraction, thermogravimetric an alysis, Brunauer-Emmett-Teller analysis, scanning electron microscopy, tran smission electron microscopy, energy dispersive spectroscopy, x-ray fluores cence, Raman and infrared spectroscopy, and Berner-type low-pressure impact or. The anatase phase transition was initiated at 500 degrees C in nitrogen and at 580 degrees C in air. Under other conditions amorphous powders were observed and transformed to nanocrystalline TiO2 via thermal postannealing . In air, smooth and spherical particles with 2-4-mu m diameter were formed with an as-expected tendency to convert to rutile in the thermal postannea lings. In nitrogen, a fraction of the titanium tetrabutoxide precursor evap orated and formed ultrafine particles via the gas-to-particle conversion. A t 500 degrees C thermally stable anatase phase was formed in nitrogen. A sp ecific surface area as high as 280 m(2) g(-1) was observed for an as-prepar ed powder.