An operando IR study of the unburnt HC effect on the activity of a commercial automotive catalyst for NH3-SCR

▶ The unburnt HCs traces decrease the DeNOx efficiency of Fe-ZSM5 for SCR-NH3 ▶ C10H22 and C7H8 hinder the reaction by pore blocking of coke deposition ▶ NOx conversion drop is also associated to a lower adsorbed NH4+ under steady state ▶ C10H22 is the most inhibiting compound due to a competitive adsorption with ammonia on the active sites.