Abstract
N 2O formation and consumption were investigated over a coupled LNT-SCR system consisting of a low-precious metal loaded Pt/Rh LNT catalyst and a commercial Cu-zeolite SCR catalyst. Under lean-rich cycling conditions, N 2O emissions from the LNT were found to be partially mitigated by the downstream SCR catalyst. N 2O decomposition over the SCR catalyst was observed in the absence of reductant immediately after the switch to rich conditions, while N 2O reduction occurred after subsequent breakthrough of the reductant from the LNT. Steady-state data indicate that the former process is weakly promoted by NO which breaks through the LNT at the same time as the N 2O. Steady-state experiments revealed the order H 2>NH 3>CO>C 3H 6 for the efficacy of N 2O reduction with different reductants. These findings suggest that coupled LNT-SCR systems can not only improve overall NO x conversion levels but can also mitigate N 2O emissions from the LNT catalyst under actual driving conditions.
| Original language | English |
|---|---|
| Pages (from-to) | 1167-1174 |
| Number of pages | 8 |
| Journal | Catalysis Letters |
| Volume | 142 |
| Issue number | 10 |
| DOIs | |
| State | Published - Oct 2012 |
Bibliographical note
Funding Information:Acknowledgments This project was funded by the U.S. Department of Energy (DOE) under award No. DE-EE0000205. The authors thank BASF for providing the catalysts used in this study. Dr. R. McCabe of Ford Motor Co. is thanked for helpful discussions.
Keywords
- Cu-zeolite
- LNT-SCR
- N O
- Nitrous oxide
- Reductant
- SCR catalyst
ASJC Scopus subject areas
- Catalysis
- General Chemistry