Effect of aging on NOx reduction in coupled LNT-SCR systems

- Coupled Pt/Rh LNT and Cu-CHA SCR catalysts were subjected to simulated road aging.
- LNT performance deteriorated due to Pt-Ba phase segregation and sulfation of the Ba phase.
- Cu-CHA performance deteriorated due to Cu2+ migration and agglomeration to form CuO.
- After aging, decreased NOx conversion over the LNT was partly compensated by the SCR catalyst.
- In addition to NH3, the SCR catalyst was able to utilize slipped CO and C3H6 as NOx reductants.