Aerosol synthesis of Ti-O powders via in-droplet hydrolysis of titanium alkoxide

A method to produce Ti-O powders by an in-droplet hydrolysis of metal alkox ide precursor is presented. Titanium n-tetrabutoxide, hydrolysis water, and acetic acid were included in the ethanolic precursor solution that was neb ulized. The resulting aerosol was transported to a tubular flow reactor whe re the ethanol evaporation initiated a polycondensation reaction and solid particles were formed starting from droplet surface. Titanium hydrous oxide particles were obtained at 200 degreesC in atmospheric pressure of nitroge n and air. The collected powders were characterized by XRD, TG-SDTA, BET, S EM, TEM, and IR- spectroscopy, as well as with aerosol impactor. The as-pro duced powder particles were amorphous, smooth on the surface, and either sp herical or deflated in shape. Aerodynamic mass mean diameter was 2.7 mum. N anocrystalline TiO2 was obtained after thermal post-annealing for one hour. An expected tendency to convert to anatase crystalline phase up to 500 deg reesC and subsequently to rutile phase up to 900 degreesC in the annealing was observed. The results show that the in-droplet hydrolysis is a viable m ethod in preparing fine Ti-O powder particles with controlled properties. ( C) 2001 Elsevier Science B.V. All rights reserved.