Impact of support and potassium-poisoning on the V2O5–WO3/ZrO2 catalyst performance in ammonia oxidation

A series of WO3-promoted zirconia supports were synthesized and calcined between 400 and 800 °C. Subsequently vanadium oxide was introduced to obtain 3.5 wt% V2O5. The influence of the calcination temperature and potassium-poisoning (K/V = 0.2, molar ratio) on the catalytic activity in the selective catalytic reduction (SCR) of NO with NH3 was previously studied. Here, we focus on the influence of these parameters on the catalytic activity for the undesirable oxidation of ammonia, which decrease the N2 selectivity of the SCR process. It is found that potassium doping of the catalysts results in a considerable decrease in the overall ammonia conversion while selectivity to NO increases.