Low temperature NOx reduction using H2-SCR for diesel vehicles
AssigneeBASF SE
InventorYuejin Li
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Abstract
Disclosed herein are emission treatment systems, articles, and methods for selectively reducing NOx compounds. The systems include a hydrogen generator, a hydrogen selective catalytic reduction (H2-SCR) article, and one or more of a diesel oxidation catalyst (DOC) and/or a lean NOx trap (LNT) and/or a low temperature NOx adsorber (LTNA). Certain articles may comprise a zone coated substrate and/or a layered coated substrate and/or an intermingled coated substrate of one or more of the H2-SCR and/or DOC and/or LNT and/or LTNA catalytic compositions.
Claims18
An emission treatment system for selectively reducing NOx compounds, the system comprising:
- a hydrogen generator;
- and
- an H2-SCR catalytic article comprising a substrate and an H2-SCR catalyst composition, the hydrogen generator being in fluid communication with, and upstream of, the H2-SCR catalytic article;
- wherein the H2-SCR catalyst composition comprises a platinum group metal component supported on a hydrogen form of zeolite or a metal oxide selected from zirconia, titania, magnesia, and combinations thereof;
- and
- a diesel oxidation catalyst (DOC) catalyst composition
- wherein the DOC catalyst composition is present in a layered catalyst coating on the H2-SCR catalytic article with a bottom layer comprising the DOC catalyst composition and an upper layer comprising the H2-SCR catalyst composition;
- and
- wherein the hydrogen generator is selected from the group consisting of on board hydrogen, hydrogen produced from alcohol reforming, hydrogen produced from ammonia decomposition, and combinations thereof.
A method for treating an exhaust stream containing NOx, comprising:
- introducing hydrogen gas into the exhaust stream to form a hydrogen-treated exhaust stream;
- passing the hydrogen-treated exhaust stream through an emission treatment system comprising
- an H2SCR catalytic article comprising a substrate and an H2SCR catalyst composition, wherein the H2SCR catalyst composition comprises a platinum group metal component supported on a hydrogen form of zeolite or a metal oxide selected from zirconia, titania, magnesia, and combinations thereof;
- and
- a diesel oxidation catalyst (DOC) catalyst composition;
- wherein the DOC catalyst composition is present in a layered catalyst coating on the H2-SCR catalytic article with a bottom layer comprising the DOC catalyst composition and an upper layer comprising the H2-SCR catalyst composition;
- and
- wherein the hydrogen generator is selected from the group consisting of on board hydrogen, hydrogen produced from alcohol reforming, hydrogen produced from ammonia decomposition, and combinations thereof.
Dependencies are inferred from the claim text.