SIMULATION OF VANADIUM OXIDE STRUCTURE ON ANATASE SURFACE BY DENSITY FUNCTIONAL THEORY

Abstract

The article is devoted to results of systematic study of the structure transformation of V2O5 supported on TiO2 (anatase). The effect of (001) TiO2-anatase on the structural properties and morphology of V2O5 was analyzed using the spin-polarized density functional theory (DFT) in the periodic approach. The calculations were performed using the VASP code with PBE energy functional and plane wave basis set. The catalyst is represented as a periodic surface. The supercell includes four Ti – O layers and the top V2O5 layer. A lot of different forms of V2O5 (monomeric and polymeric structures, individual crystallites) on the TiO2 surface were considered. According to the calculations of the adsorption energy, vanadium oxide on the oxide composite surface can form various forms. The monomeric form is the most stable. Calculated value of adsorption energy is -1.16 eV. The ionic interaction causes a significant change in the interatomic distances between the vanadium atom and the oxygen atom from the support d (V – O (Ti)) for all active forms. The highest value d (V – O (Ti)) was found for catalyst with the polymeric active form. It suggests that the binding of the form with the anatas is the smallest. Theoretical studies have shown that the V2O5/TiO2 system is dynamic and can change the surface structure under the different conditions.