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Reductive Elimination as a Mechanism for Purging a Lean NOx Trap
Technical Paper
2006-01-1067
ISSN: 0148-7191, e-ISSN: 2688-3627
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English
Abstract
The mechanism for the purging of a lean NOx trap has been investigated. For realistic purge times (e.g., 2 to 5 seconds), the stored NOx species do not decompose simply from equilibrium considerations (i.e., from the drop in O2 and NO concentrations during the rich purge). Instead, the decomposition of stored NOx is promoted by the reductants in the exhaust by a process referred to as reductive elimination. H2 is far more effective than CO or C3H6 for promoting this reductive elimination, particularly at low temperatures (e.g., 250°C). As long as H2 is available in the feedgas, H2O does not participate in the reductive elimination. However, if CO is the only reductant, H2O is needed to convert some of the CO to H2 through the water-gas-shift reaction. H2O is also important for the efficient storage of NOx during lean operation, possibly by enhancing the spillover of NO2 from a precious metal site to a NOx storage site. The kinetics of the reaction between H2 and the stored NOx have been studied with a model Ba/Pt/Al2O3 catalyst.
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Citation
Theis, J., Jen, H., McCabe, R., Sharma, M. et al., "Reductive Elimination as a Mechanism for Purging a Lean NOx Trap," SAE Technical Paper 2006-01-1067, 2006, https://doi.org/10.4271/2006-01-1067.Also In
References
- Miyoshi Naoto Matsumoto S. Katoh K. Tanaka T. Harada J. Takahashi N. Yokota K. Sgiura M. Kasahara K. “Development of New Concept Three-Way Catalyst for Automotive Lean-Burn Engines” SAE Paper no. 950809
- Sharma M. Kabin K. Harold M. P. Balakotaiah V. “Modeling of NOx Storage and Reduction for Diesel Exhaust Emission Control” SAE, 2005-16-0972 2005
- Tonkyn R. Disselkamp R. Peden C. “Nitrogen Release from a NO x storage and Reduction Catalysts” Catalysis Today
- Lesage T. Verrier C. Bazin P. Saussey J. Daturi M. “Studying the NO x -trap mechanism over a Pt-Rh/Ba/Al 2 O 3 catalyst by operando FT-IR spectroscopy” Chemical Physics 2003 5 20 4435 4440
- Obert E. Internal Combustion Engines and Air Pollution Intext Educational Publishers New York 1973 731
- Nova I. Lietti L. Castoldi L. Tronconi E. Forzatti P. “New insights in the NOx reduction mechanism with H 2 over Pt-Ba/Al 2 O 3 lean NOx trap catalysts under near-isothermal conditions,” J. Catalysis 2006