| abstract |
A substrate monolith (6) having a length L and comprising a first zone (11) of substantially uniform length defined at one end by a first end of the substrate monolith, which first zone comprising a selective catalytic reduction (SCR) catalyst for reducing oxides of nitrogen with a nitrogenous reductant in exhaust gas emitted from an internal combustion engine and a second zone (8) of substantially uniform length less than L defined at one end by a second end of the substrate monolith, which second zone comprising (a) at least one particulate metal oxide or a mixture of any two or more thereof for trapping gas phase platinum group metal (PGM), which at least one particulate metal oxide does not act as a support for any other catalytic component; or (b) a component capable of trapping and/or alloying with gas phase PGM. |