Characterization and catalytic properties of MoO3-V2O5/Nb2O5 catalysts

The influence of molybdenum oxide on the dispersion of vanadium oxide supported on niobia was investigated, A series of MoO3-V2O5/Nb2O5 catalysts with varying MoO3 content ranging from 1% to 5% (w/w) with fixed V2O5 content were prepared by impregnation of previously prepared 5 wt% V2O5/Nb2O5 with requisite amounts of ammonium molybdate solution. X-ray diffraction patterns indicate the presence of beta-(Nb, V)(2)O-5 phase with the addition of MoO3 up to a loading of 3 wt%. Temperature-programmed reduction (TPR) results suggest that the reducibility is decreasing with MoO3 loading. The results of temperature programmed desorption (TPD) of ammonia suggest that the acidity of the catalysts increased with the addition Of MoO3. The catalytic properties of the catalysts in the ammoxidation of 3-picoline were correlated with the characterization data. (C) 2002 Elsevier Science B.V. All rights reserved.