PREPARATION, CHARACTERIZATION, AND CATALYTIC PROPERTIES FOR THE SCR OF NO BY NH3 OF V2O5 TIO2 CATALYSTS PREPARED BY EQUILIBRIUM DEPOSITION FILTRATION/

V2O5/TiO2 catalysts of varying vanadium content were prepared at vario us pH's and concentrations of the impregnation solution using the equi librium deposition filtration (EDF) method. Moreover, corresponding ca talysts were prepared using the conventional wet impregnation (WI) met hod. The above catalysts were exhaustively characterized using BET, AE M, FT-IR, DRS, LRM, XPS, TPR, and TPD of NH3 and tested for the SCR of NO by NH3 in the temperature range 250-450 degrees C. It was found th at the application of EDF results in V2O5/TiO2 catalysts with relative ly high dispersity of the vanadia supported phase, homogeneous distrib ution of this phase on the support particles, and quite strong interac tions between the supported vanadia phase and the surface of titania, and inhibits the formation of supported V2O5 crystallites. The catalys ts prepared by EDF exhibited better activity and selectivity than thos e prepared by conventional WI. Decrease of the impregnation pH in the EDF preparations from 8 to 4.5 caused an increase in the vanadium cont ent from 2.6 to 3.6 wt % V2O5 which, in turn, provoked very important differences in the physicochemical properties of the EDF catalysts (in crease of the surface coverage of the titania by the vanadia phase and decrease of the mean value of the vanadia phase-support interactions) . The above explained the increase, with the vanadium content, of the activity and selectivity of the V2O5/TiO2 EDF catalysts.