Electronic Structure and Stability of Peroxide Divanadate Species V(O-O) on the TiO2(001) Surface Reconstructed

Electronic Structure and stability of the VO4 species forming on the anatase-TiO2(001)-(4 x 1) reconstructed surface at redox cycle V5+-O-V5+ reversible arrow V4+-O-V-4 have been investigated on the basis of periodic density functional theory calculations. It is shown that oxidizing of the key intermediate of Mars-van Krevelen mechanism [O-V4+-O-V4+] by the gas phase dioxygen leads to the substantial structure relaxation of the surface VOx species within a monolayer. As a result, the binding energy of the vanadyl bond V=O decreased and the stable peroxide complex V(O-O) can be formed on the fully oxidized VOx/TiO2 surfaces. This complex manifests itself as a peak near Fermi level (-0.23 eV) in the total density of states (DOS) and O-projected density of states (PDOS).