(180a) Multi-Layer Monolith Catalysts for Lean NOx Reduction

Harold, M. P., University of Houston
Shakya, B. M., University of Houston
Balakotaiah, V., University of Houston
Luss, D., University of Houston
Shrestha, S., University of Houston
Zheng, Y., University of Houston
Metkar, P. S., University of Houston
Liu, Y., Cummins Inc.
Kamasamudram, K., Cummins Inc.
Yezerets, A., Cummins Inc.

The challenge of  achieving high NOx conversion and N2 selectivity and minimal release of unreacted NOx and NH3 in lean burn vehicle emission aftertreatment calls for structured catalysts with multiple functions.  We describe experimental and modeling studies of three different multi-layer applications. The first application combines Fe- and Cu-exchanged zeolitic layers to expand the high NOx conversion temperature range.  The second application combines periodic NOx storage and reduction with in situ NH3 generation and selective catalytic reduction.  The third application combines a Pt/Al2O3 bottom layer and a zeolitic toplayer to oxidize NH3 with high selectivity to N2.