Abstract
Different methods of preparation have been used to introduce iron species in the zeolite ZSM-5. Special consideration has been devoted to the FeCl3 sublimation method. The various samples have been characterised by XRD and temperature programmed reduction. Two general types of species have been identified: iron oxide aggregates and iron cationic species. In the SCR of NO by NH3, Fe-ZSM-5 prepared from sublimation of FeCl3 displays the highest activity which is assumed to be related to the formation of iron-oxo complexes. The formation of these species is enhanced by a rapid washing of the preparation after the sublimation of FeCl3 following by a calcination with 5–10%O2 atmosphere. The SCR activity has been correlated with the activity in oxidising NO to NO2.