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

Abstract

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, O2 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 O2 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 O2 resistance in N2O reduction process. The characterization results from UV–vis DR spectra and XPS indicated that α-sites are the main active sites in Fe-Z-pH2, and they were inert to O2 but highly active to N2O. It could be concluded that the competition effect between N2O and O2 was very important over different catalysts. O2 is more prevalent over α-Fe2O3 catalyst, while N2O dominates over Fe-Z-pH2 catalyst. Moreover, in the presence of O2, 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.