Influence of oxygen nonstoichiometry and doping with 2p-, 3p-, 6p- and 3d-elements on electronic structure, optical properties and photocatalytic activity of rutile and anatase: Ab initio approaches

•Doping – the main way of improving the photocatalytic activity of TiO2.•The possibilities of ab initio methods in description of doped TiO2 properties.•Theoretical description of electronic structure of TiO2 is a difficult task.•Calculations of optical properties of TiO2 doped with 2p-, 3p-, 6p-, 3d-elements.•Within LDA + U approximation, etc., optical spectra are in agreement with experiments.

Among wide-energy-gap semiconductors, doped titanium dioxides (anatase or/and rutile polymorphs) are the most promising materials for designing photocatalysts active in the visible region of solar spectrum, for photodegradation of organic molecules and for photolysis of water. It has been established recently that doping of titanium dioxides with 2p-, 3p-, 6p- and 3d-elements significantly increases their photocatalytic activity. In this review we summarize calculation results on the electronic structure and optical properties of bulk stoichiometric and nonstoichiometric rutile and anatase and their doped compounds obtained by means of ab initio methods of condensed matter physics: the linearized muffin-tin orbital method, the linearized augmented plane-wave method, the plane-wave pseudopotential method, the coherent potential method, the Hartree–Fock method, etc. The possibilities and restrictions of the methods for accurate calculations of the electronic structure and optical properties of stoichiometric and nonstoichiometric titanium dioxides and titanium dioxides doped with 2p-, 3p-, 6p- and 3d-elements are discussed. As calculated with the included Coulomb correlation correction, within the hybrid potential approximation or with the self-interaction correction taken into account, the electronic structure and optical spectrum are in agreement with the experimental data. The results of the calculations correspond to the observed photocatalytic activity of rutile and anatase.

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