A porous ZrO2-SiO2 mixed oxide catalyst support was synthesized by a sol-ge
l method using 2,4-pentane dione as the complexing agent. A series of suppo
rted vanadia catalysts with V2O5 contents ranging from 1-10 wt% were prepar
ed using the ZrO2-SiO2 mixed oxide as the support. Characterization techniq
ues such as BET surface area, solid-state V-51 and H-1 MAS NMR, and diffuse
reflectance FT-IR were employed for the structural elucidation studies of
the support and catalysts. Partial oxidation activities of the catalysts we
re determined using ethanol oxidation as the model reaction. V-51 NMR studi
es indicated the presence of tetrahedally coordinated vanadate species at l
ower vanadia contents and octahedral vanadyl species at higher V2O5 loading
s. H-1 MAS NMR spectra showed peaks corresponding to hydroxyl groups of zir
conia and silica. Ethanol partial oxidation activities of the catalysts ind
icated higher acetaldehyde selectivity for the V/Zr-Si catalysts in compari
son to the V2O5/ZrO2 and V2O5/SiO2 catalysts. (C) 1999 Academic Press.