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New Insights into Reaction Mechanism of Selective Catalytic Ammonia Oxidation Technology for Diesel Aftertreatment Applications
- Krishna Kamasamudram - Cummins Inc. ,
- Aleksey Yezerets - Cummins Inc. ,
- Xu chen - Cummins Inc. ,
- Neal Currier - Cummins Inc. ,
- Mario Castagnola - Johnson Matthey Inc ,
- Hai-Ying Chen - Johnson Matthey Inc ,
- Krishna Kamasamudram - Cummins Inc ,
- Aleksey Yezerets - Cummins Inc ,
- Xu chen - Cummins Inc ,
- Neal Currier - Cummins Inc
ISSN: 1946-3936, e-ISSN: 1946-3944
Published April 12, 2011 by SAE International in United States
Citation: Kamasamudram, K., Yezerets, A., chen, X., Currier, N. et al., "New Insights into Reaction Mechanism of Selective Catalytic Ammonia Oxidation Technology for Diesel Aftertreatment Applications," SAE Int. J. Engines 4(1):1810-1821, 2011, https://doi.org/10.4271/2011-01-1314.
Mitigation of ammonia slip from SCR system is critical to meeting the evolving NH₃ emission standards, while achieving maximum NOx conversion efficiency. Ammonia slip catalysts (ASC) are expected to balance high activity, required to oxidize ammonia across a broad range of operating conditions, with high selectivity of converting NH₃ to N₂, thus avoiding such undesirable byproducts as NOx or N₂O. In this work, new insights into the behavior of an advanced ammonia slip catalyst have been developed by using accelerated progressive catalyst aging as a tool for catalyst property interrogation. The overall behavior was deconstructed to several underlying functions, and referenced to an active but non-selective NH₃ oxidation function of a diesel oxidation catalyst (DOC) and to the highly selective but minimally active NH₃ oxidation function of an SCR catalyst. In particular, it was shown that different functions of the ASC degrade independently, resulting in minimal changes to NH₃ conversion with substantial changes to product selectivity.