Abstract. In the last decade, titanium dioxide has attracted increasing attention of researchers due to the prospects for their use as high-performance photo-catalysts and photo-sorption to synthesize organic compounds according to green chemistry principles. It is expected that nonstoichiometric titanium dioxide will be most useful for modern photoapplications, because this material absorbs visible light. Stoichiometric TiO2 does not absorb visible light; therefore, exposure to the harmful and expensive UV radiation is required for its functioning. An efficient way for increasing the titanium dioxide non-stoichiometry is to generate structural defects, in particular, oxygen vacancies, which would change the optical and electronic properties of the material. The point defects present in the crystal lattice give rise to additional levels in the energy gap of TiO2, which, in turn, causes a decrease in the efficient band gap and a shift of the photosensitivity to the visible range.

The presentation gives description of synthesis and modification of titanium dioxide by chemical, electrochemical and mechanic-chemical methods. Atomistic structure, nanostructure, morphology, semiconductor peculiarities, optical characteristics and functional properties of prepared titanium dioxides are described. Areas of practical uses of titanium dioxide in catalysis, technics and biomedicine are considered.