Low-temperature selective catalytic reduction of N2O by CO over Fe-ZSM-5 catalysts in the presence of O2

Nitrous oxide (N2O) is an important ozone-depletion substance and greenhouse gas. Selective catalytic reduction (SCR) of N2O by CO is considered an effective method for N2O elimination. However, O-2 exhibited a significant inhibition effect on the catalytic performance of N2O reduction by CO. A series of iron-based catalysts were prepared to investigate the effect of O-2 in SCR of N2O by CO. The Fe-Z-pH2 (Fe-ZSM-5 ion-exchanged under pH of 2) catalyst manifested superior activity at low temperature and excellent O-2 resistance in N2O reduction process. The characterization results from UV-vis DR spectra and XPS indicated that a-sites are the main active sites in Fe-Z-pH2, and they were inert to O-2 but highly active to N2O. It could be concluded that the competition effect between N2O and O-2 was very important over different catalysts. O-2 is more prevalent over alpha-Fe2O3 catalyst, while N2O dominates over Fe-Z-pH2 catalyst. Moreover, in the presence of O-2, Fe-Z-pH2 exhibited better performance for N2O removal than non-noble mixed oxide catalysts, which might broaden the application of low-temperature SCR of N2O by CO.