Alternative alkali resistant deNO_x 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).