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Why Cu- and Fe-Zeolite SCR Catalysts Behave Differently At Low Temperatures

Journal Article
2010-01-1182
ISSN: 1946-3952, e-ISSN: 1946-3960
Published April 12, 2010 by SAE International in United States
Why Cu- and Fe-Zeolite SCR Catalysts Behave Differently At Low Temperatures
Sector:
Citation: Kamasamudram, K., Currier, N., Szailer, T., and Yezerets, A., "Why Cu- and Fe-Zeolite SCR Catalysts Behave Differently At Low Temperatures," SAE Int. J. Fuels Lubr. 3(1):664-672, 2010, https://doi.org/10.4271/2010-01-1182.
Language: English

Abstract:

Cu- and Fe-zeolite SCR catalysts emerged in recent years as the primary candidates for meeting the increasingly stringent lean exhaust emission regulations, due to their outstanding activity and durability characteristics. It is commonly known that Cu-zeolite catalysts possess superior activity to Fe-zeolites, in particular at low temperatures and sub-optimal NO₂/NOx ratios. In this work, we elucidate some underlying mechanistic differences between these two classes of catalysts, first based on their NO oxidation abilities, and then based on the relative properties of the two types of exchanged metal sites. Finally, by using the ammonia coverage-dependent NOx performance, we illustrate that state-of-the-art Fe-zeolites can perform better under certain transient conditions than in steady-state.