E. V. Mostovshchikova, B. A. Gizhevsky, L. V. Ermakova
IR ABSORPTION SPECTRA OF TiO2 SUBMICRON POWDERS SYNTHESIZED BY THE COMBUSTION METHOD
A method for synthesizing titanium dioxide using a combustion reaction has been developed, and TiO2 powders with anatase structure have been obtained. The average particle size
(~ 500 nm) and the size of the coherent scattering region (~ 15 nm) are determined, as well as the specific surface, which depends on the type of fuel used in the reaction (5.5 m2/g for glycine and 30.5 m2/g for citric acid). Annealing in the air at temperatures up to T = 1050 °C leads to a change in the structural modification, resulting in powders with a rutile structure. The IR optical density spectra D(λ) (1 to 12 μm) of TiO2 powders are studied. The intense absorption band in the spectra is found, the position of which depends on the structural modification of TiO2 (1.8 μm to 3.1 μm). The analysis of the D(λ) spectra demonstrates that this band is a superposition of two absorption bands, one of which has a maximum at 1.2 μm and can be associated with Ti3+ ions, the other being due to the polaron-type charge carriers.
Keywords: titanium dioxide, methods for synthesizing fine powders, anatase, rutile, IR spectroscopy