Diesel oxidation catalyst composites
AssigneeBASF SE
InventorsShiang Sung, Stanley A. Roth, Claudia Wendt, Susanne Stiebels, Helke Doering
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Abstract
Oxidation catalyst composites for the treatment of exhaust gas emissions, such as the abatement of unburned hydrocarbons (HC), and carbon monoxide (CO) and the oxidation of NO to NO2 are disclosed The catalyst composites comprise two washcoat layers containing two different compositions of platinum group metals to optimize the NO2 exiting the catalyst composite. The key to improvement in NO oxidation is to have one catalyst layer that contains Pt while being substantially free of Pd. Methods and systems utilizing the catalyst composites are also disclosed.
Claims23
An oxidation catalyst composite for abatement of exhaust gas emissions from a lean burn engine comprising:
- a carrier substrate having a length, an inlet end and an outlet end, an oxidation catalyst catalytic material on the carrier, the oxidation catalyst catalytic material including a bottom washcoat layer and a top washcoat layer;
- the bottom washcoat layer comprising a refractory metal oxide support, a platinum (Pt) component and a palladium (Pd) component in weight ratio of Pt to Pd in the range of about 4:1 to 1:4;
- and
- the top washcoat layer comprising a zeolite, Pt and a refractory metal oxide support, the top washcoat layer being substantially free of palladium, the oxidation catalyst composite being effective to abate hydrocarbon and carbon monoxide, and oxidize NO to NO2 in the lean burn engine exhaust;
- and wherein the top washcoat layer contains a higher loading of platinum group metals than the bottom washcoat layer to maximize NO oxidation.
An oxidation catalyst composite for abatement of exhaust gas emissions from a lean burn engine comprising:
- a carrier substrate having a length, an inlet end and an outlet end, an oxidation catalyst catalytic material on the carrier, the oxidation catalyst catalytic material including a bottom washcoat layer and a top washcoat layer;
- the bottom washcoat layer comprising a refractory metal oxide support, a platinum (Pt) component and palladium (Pd) component in the weight ratio of Pt to Pd in the range of about 9:1 to 1:4;
- and
- the top washcoat layer comprising a zeolite, a refractory metal oxide support, a platinum component (Pt) and palladium component (Pd) in the weight ratio of Pt to Pd in the range of about 1:1 to 100:1, the oxidation catalyst composite being effective to abate hydrocarbon and carbon monoxide, and oxidize NO to NO2 in the lean burn engine exhaust.
An oxidation catalyst composite for abatement of exhaust gas emissions from a lean burn engine comprising:
- a carrier substrate having a length, an inlet end and an outlet end, an oxidation catalyst catalytic material on the carrier, the oxidation catalyst catalytic material including a bottom washcoat layer and a top washcoat layer;
- the top washcoat layer comprising a refractory metal oxide, zeolite and a platinum component (Pt) and a palladium component (Pd) in a weight ratio of Pt to Pd in the range of about 9:1 to 1:4;
- and
- the bottom washcoat layer comprising Pt and a refractory metal oxide support, the oxidation catalyst composite being effective to abate hydrocarbon and carbon monoxide, and oxidize NO to NO2 in the lean burn engine exhaust.
Dependencies are inferred from the claim text.