Selective catalytic reduction of nitrous oxide over Fe-ZSM-5: the effect of ion-exchange level

The direct decomposition and selective reduction of nitrous oxide (N2O) over Fe-ZSM-5 have been investigated in the presence of oxygen, using propene (C3H6) as reductant. The results are compared with those obtained over Cu-ZSM-5, which is known to possess very high activity for direct decomposition. When propene was added as reductant, the activity of Fe-ZSM-5 dramatically increased compared with the direct decomposition of N2O, whereas Cu-ZSM-5 was strongly deactivated. Some Fe-ZSM-5 catalysts having different ion-exchange levels have been prepared in order to investigate the effect of Fe ion on the selective reduction of N2O. The conversion of N2O to N-2 and the reactivity of absorbed C3H6 with N2O were increased with increased ion-exchange level. The activity over Fe-ZSM-5 lion-exchange level=81%) after calcination at 1073 K was found to be slightly higher than that at 773 K. Moreover, the observation of FT-IR spectroscopy after adsorption of C3H6 or pyridine on the catalyst showed that most of the Bronsted sites after calcination at 1073 K had disappeared. The results suggest that this reaction occurs mainly on Leu is acidic sites generated after the ion-exchange. (C) 2000 Elsevier Science B.V. All rights reserved.