REAL STRUCTURE OF TIO2 IN SAMPLES OF THE TIO2-V2O5 SYSTEM

Measurements of electron spin resonance (ESR) spectra and X-ray structure analysis have been performed on samples of the TiO2-V2O5 system, formed by anatase crystallites on the surface of which a thin layer of V2O5 was deposited by thermal decomposition of ammonium vanadate at 800-degrees-C. It was found that the deposited V2O5 gives rise to a change in the modification of TiO2 (anatase goes over to rutile) and to a decrease in the volume of the TiO2 elementary cell. Bands corresponding to Ti atoms of oxidation state + III were identified in the ESR spectrum of the initial TiO2. The intensity of these bands decreases with increasing content of V2O5 in the TiO2-V2O5 samples; the ESR spectra of the samples with high V2O5 content exhibit only one band corresponding to vanadium atoms in oxidation state + IV in the rutile lattice. The experimental results allow one to form an idea on the changes of the real structure of TiO2 in connection with the deposition of V2O5 thin films on TiO2 crystallites and with thermal treatment of these materials.