Filter comprising combined soot oxidation and NH3-SCR catalyst
AssigneeJohnson Matthey Public Limited Company
InventorsJillian Elaine Collier, Ralf Dotzel, Sylvie Cécile Laroze, Rainer Leppelt, Paul James Millington, Jörg Werner Münch, Raj Rao Rajaram, Hubert Schedel
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Abstract
A wall-flow filter for filtering particulate matter from a flowing exhaust gas comprises a catalyst for catalyzing both the conversion of solid carbon in the particulate matter by oxygen and the selective reduction of oxides of nitrogen in the exhaust gas with a nitrogenous reductant, which catalyst comprising optionally stabilized ceria and at least one metal selected from (i) tungsten and (ii) both tungsten and iron.
Claims18
A method of treating exhaust gas emissions from internal combustion engines and having oxides of nitrogen and soot, which method comprising passing the exhaust gas through a wall-flow filter in the presence of a nitrogenous reductant, which filter comprising a layer of catalyst coated on an inert filter substrate, and
- catalysing soot combustion by oxygen and selective reduction of oxides of nitrogen,
- the steps of catalyzing soot combustion by oxygen and selective reduction of oxides of nitrogen each consisting of contacting the exhaust gas to the layer of the catalyst,
- the catalyst comprises ceria that is optionally stabilised and at least one metal selected from (i) tungsten and (ii) both tungsten and iron.
Dependencies are inferred from the claim text.