Reactivity of V2O5 with TiO2-ZrO2 mixed oxide: An X-ray diffraction study

Abstract

The reactivity of vanadia with TiO2-ZrO2 mixed oxide support was investigated by the X-ray powder diffraction technique. TiO2-ZrO2 mixed oxide was prepared by the technique of precipitation from homogeneous solution. Ammonium metavanadate was used as a source of vanadia, and V2O5 contents varied from 2 to 16 wt%. Calcination of Ti- and Zr-hydroxides at 773 K result in the formation of an amorphous phase, and further heating at 873 K converts this amorphous phase into a crystalline TiO2 · ZrO2 compound. This compound is quite stable in the absence of V2O5. Addition of V2O5 and heating of the samples beyond 873 K result in the formation ZrV2O7, with the simultaneous presence of TiO2 rutile phase. Quantities of these phases increase with increasing in V2O5 content