Activity and deactivation of sulphated TiO2- and ZrO2-based V, Cu, and Fe oxide catalysts for NO abatement in alkali containing flue gases

Vanadia, copper and iron oxide catalysts supported on conventional TiO2, ZrO2, and sulphated-TiO2 and ZrO2 have been prepared. These catalysts were characterized by elemental analysis, N2-BET, XRD, and NH3-TPD methods. The influence of potassium oxide additives on the acidity and activity in NO selective catalytic reduction (SCR) with ammonia was studied. The absolute activity of the samples does not vary significantly depending on the nature of the active metal and the acidic properties of the support used, seem to be influenced mainly by the concentration of active metal. Loading of the catalysts with potassium leads to a considerable decrease of their catalytic activity. In the case of the traditional carriers (TiO2, ZrO2), the poisoning of the catalyst with small amounts of potassium oxide (K/metal ratio