Phase development in the catalytic system V2O5/TiO2 under oxidising conditions

The target of this work was to investigate phase development in the catalyst system consisting of TiO2 (Anatase) and V2O5 (Shcherbinaite). Thus a set of V2O5/TiO2 specimens was prepared by ball milling and exposed to subsequent annealing in air in the temperature range from 400 to 700 °C. The XRD-results showed the presence of Anatase and Shcherbinaite as the only phases up to 525 °C. For temperatures above 525 °C Rutile as a new TiO2-phase occured. Peak intensities and positions were shifted. No loss of oxygen or vanadium was detected. The reaction involves the formation of a Rutile solid solution containing VOx species. XPS studies showed an oxidation state of 4.75 for V in the Rutile solid solution as compared to 4.65 in the Shcherbinaite. The Rutile solid solution was first found at 525 °C < T < 550 °C for compositions of 3 mole % < V2O5 < 5 mole %. The phase field for Rutile solid solutions extends to 10 mole%< V2O5