摘要 |
A wall-flow filter comprises first channels and second channels, wherein the first channels comprise a NO x absorber catalyst (NAC) comprising a catalytic oxidation component and the second channels comprise a catalyst for selective catalytic reduction (SCR) of nitrogen oxides (NO x ) with nitrogenous reductant, wherein the wall-flow filter comprises a length extending from a first end to a second end, wherein the NAC is located in a first zone of substantially uniform length from 30-70% of the wall-flow filter length with an upstream zone end defined by the first end of the wall-flow filter. |