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 various pH's and concentrations of the impregnation solution using the equilibrium deposition filtration (EDF) method. Moreover, corresponding catalysts were prepared using the conventional wet impregnation (WI) method. The above catalysts were exhaustively characterized using BET, AEM, 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 that the application of EDF results in V2O5/TiO2 catalysts with relatively high dispersity of the vanadia supported phase, homogeneous distribution of this phase on the support particles, and quite strong interactions between the supported vanadia phase and the surface of titania, and inhibits the formation of supported V2O5 crystallites. The catalysts prepared by EDF exhibited better activity and selectivity than those prepared by conventional WI. Decrease of the impregnation pH in the EDF preparations from 8 to 4.5 caused an increase in the vanadium content from 2.6 to 3.6 wt % V2O5 which, in turn, provoked very important differences in the physicochemical properties of the EDF catalysts (increase 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.