Chemical Structures of ZrO 2 -Supported V−Sb Oxides

Abstract

The effect of the vanadium and/or antimony loading on the structure of zirconia and zirconium hydroxide on calcination is studied by X-ray diffraction and Raman spectroscopy. Vanadia promotes the transition of tetragonal to monoclinic zirconia at high temperatures. The interaction of dispersed vanadium oxide species with a zirconia support leads to the formation of ZrV2O7, which is easier on uncalcined zirconium hydroxide. Antimony tends to stabilize the tetragonal phase of zirconia and its specific area. The simultaneous presence of Sb and V on zirconia at low coverage leads to a preferential interaction of individual V and Sb oxides on the zirconia surface rather than the formation of a binary Sb−V oxide. However, at high Sb−V coverage, SbVO4 is formed at the expense of surface V oxide, while the transition to monoclinic polymorph is minimized. Simultaneously, the excess of antimony forms α-Sb2O4.