FIELD: chemistry.
SUBSTANCE: described are catalyst articles having a first zone comprising a first SCR catalyst and a second zone comprising an ammonia slip catalyst (ASC), where the ammonia slip catalyst contains a second SCR catalyst and an oxidation catalyst, and the ASC has a DOC functionality, where the first zone is located on the input side of the substrate, and the second zone is located on the output side of the substrate, and where ASC is two-layer, wherein the lower layer contains an oxidation catalyst, and the upper coating layer contains a second SCR catalyst. Described also is exhaust gas exhaust system comprising such catalyst articles, and methods of using catalyst articles in SCR processes, where amount of ammonia breakthrough decreases and hydrocarbons are oxidized by ASC catalyst.
EFFECT: catalyst articles are suitable for reducing concentrations of NOx in exhaust gases using a selective catalyst (SCR), to reduce the amount of ammonia slippage and to oxidize organic residues.
36 cl, 18 dwg
| Title | Year | Author | Number |
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