Enhanced Durability of Monolithic V2O5-WO3/TiO2 Catalysts Prepared by a Novel One-Pot Method for the Selective Catalytic Reduction of NOx with NH3

In the present work, V2O5-WO3/TiO2 (VWT) catalysts were loaded onto a cordierite monolith through a novel one-pot method (OP) and a traditional incipient wetness impregnation method (IW). The catalysts were characterized and evaluated for NH3-SCR before and after hydrothermal aging at 600 degrees C for 36 h. An analysis of catalyst activity showed that the hydrothermal stability of OP was much higher than that of IW. N-2-sorption and X-ray diffraction (XRD) results suggested that there were no significant differences in the textural and structural properties of the two catalysts before and after aging, except for the formation of a small amount of WO3 crystallites on the surface of aged OR. Separate NH3-oxidation tests revealed that the NO selectivity of aged OP was significantly lower than that of aged IW, which resulted in a much higher NOx conversion at high temperatures during NH3-SCR. X-ray photoelectron spectroscopy (XPS), H-2-temperature programmed reduction (H-2-TPR), and Raman spectroscopy indicated that V and W species were more stable on the surface of OP during aging rather than IW, thus inhibiting the aggregation of surface-active species and leading to a better hydrothermal stability. Furthermore, OP exhibited better adhesion of the washcoat when compared to IW and this VWT catalyst exhibited a good tolerance for SO2.