Aerosol synthesis of titanium oxide particles by in-droplet hydrolysis method

A method to produce titanium oxide powders by in-droplet hydrolysis of metal alkoxide precursor was studied. Onset of titanium dioxide crystallization on the aerosol particles was investigated. Titanium hydrous oxide particles were prepared starting from an acetic acid modified titanium alkoxide precursor solution aerosol at 200 °C in tube flow reactor. Titanium n-tetrabutoxide, hydrolysis water, and acetic acid were included in the ethanolic precursor solution that was nebulized. The droplets were transported to a tubular flow reactor where the chemical reactions formed solid particles. The powders were characterized by XRD, TG-SDTA, BET, SEM, TEM, EDS, XRF, IR- spectroscopy, and with aerosol impactor. Micron sized powder particles were amorphous, smooth on the surface, and either spherical or deflated in shape. Subsequently, titanium dioxide particles were produced by thermal post-annealing of the powders in air. The onset of crystallization of aerosol particles to nanocrystalline TiO2 was investigated at 500 °C reactor temperature. Thinned particles were studied and the initial crystallization was observed to be localized on the surface of the particles