Emission Treatment Catalysts, Systems and Methods
AssigneeBASF Catalysts LLC
InventorsKenneth E. Voss, Kevin A. Hallstrom, Sanath V. Kumar, Susanne Stiebels, Marius Vaarkamp
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Abstract
Zoned diesel oxidation catalysts containing a higher precious metal loading in the inlet zone that the outlet zone and an equal or shorter length inlet zone are described. Emission treatment systems and methods of remediating nitrogen oxides (NOx), particulate matter, and gaseous hydrocarbons using zoned diesel oxidation catalysts are also described.
Claims31
A diesel oxidation catalyst comprising an inlet zone with an axial length and an outlet zone with an axial length, the inlet zone comprising at least one of platinum and palladium in a first loading, the outlet zone comprising palladium in a second loading, the outlet zone comprises substantially no platinum, the first loading being greater than the second loading and the axial length of the inlet zone being less than or equal to the axial length of the outlet zone.
A method of making a diesel oxidation catalyst, comprising:
- preparing a first slurry comprising platinum and palladium;
- preparing a second slurry comprising palladium;
- washcoating an inlet zone of a substrate with the first slurry to a first loading, the inlet zone having an axial length;
- and
- washcoating an outlet zone of the substrate with the second slurry to a second loading, the outlet zone having an axial length,
- wherein the first loading is greater than the second loading and the axial length of the inlet zone is less than or equal to the axial length of the outlet zone.
The method of claim 22, wherein the axial length of the inlet zone is about half the axial length of the outlet zone.
The system of claim 27, wherein the outlet zone of the catalyst comprises substantially no platinum.
The system of claim 30, further comprising a selective catalytic reduction catalyst disposed downstream of the catalyzed soot filter.
Dependencies are inferred from the claim text.