| abstract |
The present invention provides catalytic articles, methods and systems for treating lean combustion engine exhaust. The catalyst article includes a selective catalytic reduction catalyst on a particulate filter. The SCR catalyst on the particulate filter results in limited NO x conversion, which results in the promotion of passive oxidation of soot collected on the particulate filter by reaction with NO 2, with unconverted NO x 2 can be used. The systems and methods utilize such catalytic articles and further include a selective catalytic reduction catalyst on, for example, a downstream flow-through support. |