Characterization of vanadium oxide supported on zirconia and modified with MoO3

Abstract

Vanadium oxides supported on zirconia and modified with MoO3 were prepared by adding Zr(OH)4 powder into a mixed aqueous solution of ammonium metavanadate and ammonium molybdate followed by drying and calcining at high temperatures. The characterization of prepared catalysts was performed using FTIR, Raman spectroscopy and solid-state 51V NMR. In the case of a calcination temperature of 773 K, for samples containing low loading of V2O5, below 15 wt %, vanadium oxide was in a highly dispersed state, while for samples containing high loading of V2O5, equal to or above 15 wt %, vanadium oxide was well crystallized because the V2O5 loading exceeded the formation of a monolayer on the surface of ZrO2. The ZrV2O7 compound was formed through the reaction of V2O5 and ZrO2 at 873 K and the compound decomposed into V2O5 and ZrO2 at 1073 K, which were confirmed by FTIR spectroscopy and solid-state 51V NMR. IR spectroscopic studies of ammonia adsorbed on V2O5-MoO3/ZrO2 showed the presence of both Lewis and Brönsted acids.