Alternative alkali resistant deNOx catalysts

Alternative alkali resistant deNOx catalysts were prepared using three different supports ZrO2, TiO2 and Mordenite zeolite. The majority of the catalysts were prepared by incipient wetness impregnation of a commercial support, with vanadium, copper or iron precursor, one catalyst was prepared by onepot sol–gel method. All catalysts were characterized by BET, XRPD and NH3-TPD. Initial SCR activities of 8 out of 9 catalysts showed higher NO conversion at least at one temperature in the temperature range 300–500 °C compared to the conventional V2O5-WO3/TiO2 catalyst. After potassium poisoning (100–130 μmol of K/g of catalyst) the relative drop in SCR activity and acidity was lower for all the alternative catalysts compared to the industrial V2O5-WO3/TiO2 catalyst. Furthermore, Cu/MOR and Nano-V2O5/Sul-TiO2 catalysts showed 8–16 times higher SCR activities than the conventional even after high potassium doping (250 and 280 μmol of K/g, respectively). The increased poisoning resistance was due to high substrate acidity (sulphated, heteropoly acid promoted and zeolite supports), substituting the active species of the catalyst (other than vanadium species, i.e. Cu, Fe) and new catalyst synthesis methods (Nano-V2O5/Sul-TiO2 catalyst prepared by sol–gel method).