PASSIVE NOx ADSORBER
AssigneeJohnson Matthey Public Limited Company
InventorsAndrew Francis CHIFFEY, Jack CORPS, Laura MITCHELL-DOWNIE, Francois MOREAU, Matthew O'BRIEN
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Abstract
A NOx absorber catalyst for treating an exhaust gas from a lean burn engine. The NOx absorber catalyst comprises a molecular sieve catalyst comprising a noble metal and a molecular sieve, wherein the molecular sieve contains the noble metal; an oxygen storage material for protecting the molecular sieve catalyst; and a substrate having an inlet end and an outlet end.
Claims13
A NOx absorber catalyst for treating an exhaust gas from a lean burn engine comprising:
- a first layer comprising an oxygen storage material effective for protecting the molecular sieve catalyst by preventing the molecular sieve catalyst from becoming deactivated to NOx storage when exposed to rich exhaust gas conditions;
- a second layer comprising a molecular sieve catalyst comprising a noble metal and a molecular sieve, wherein the molecular sieve contains the noble metal, and wherein the noble metal comprises palladium;
- and
- a substrate having an inlet end and an outlet end;
- wherein the first layer is disposed on the second layer.
A NOx absorber catalyst according to claim 7, wherein the oxygen storage material for protecting the molecular sieve catalyst comprises an oxide of cerium the oxygen, palladium, and optionally platinum, supported on the oxide of cerium.
Dependencies are inferred from the claim text.