Catalysts for treating transient NOx emissions
AssigneeJohnson Matthey Public Limited Company
InventorsGuy Richard Chandler, Alexander Nicholas Michael Green, Joanne Elizabeth Melville, Paul Richard Phillips, Stuart David Reid
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Abstract
A heterogeneous catalyst article having at least one combination of a first molecular sieve having a medium pore, large pore, or meso-pore crystal structure and optionally containing a first metal, and a second molecular sieve having a small pore crystal structure and optionally containing a second metal, and a monolith substrate onto or within which said catalytic component is incorporated, wherein the combination of the first and second molecular sieves is a blend, a plurality of layers, and/or a plurality of zones.
Claims14
A catalyst composition for treating exhaust gas comprising:
- (a) a first molecular sieve having BEA framework, wherein said first molecular sieve is a zeolite aluminociliate and contains about 0.5 to about 5 weight percent exchanged or free iron;
- and
- (b) a second molecular sieve having a small pore crystal structure and containing about 0.5 to about 5 weight percent of exchanged or free metal selected from Cr, Mn, Fe, Co, Ce, Ni, Cu, Zn, Ga, Mn, Ru, Rh, Pd, Pt, Ag, In, Sn, Re, and Ir, wherein the second molecular sieve is a zeolite aluminosilicate having a silica-to-alumina ratio of about 8 to about 150,
- wherein said first molecular sieve and said second molecular sieve are present in a weight ratio of about 0.1 to about 1.0.
A catalytic article comprising:
- a. an extruded monolith comprising a first molecular sieve having a BEA framework, wherein said first molecular sieve is an aluminosilicate or an ferrosilicate and contains about 0.5 to about 5 weight percent exchanged or free iron;
- and
- b. a washcoat comprising a second molecular sieve having a small pore crystal structure and containing about 0.5 to about 5 weight percent of exchanged or free metal selected from Cr, Mn, Fe, Co, Ce, Ni, Cu, Zn, Ga, Mo, Ru, Rh, Pd, Pt, Ag, in, Sn, Re, and Ir, wherein the second molecular sieve is a zeolite,
- wherein the washcoat is coated on the extruded monolith.
Dependencies are inferred from the claim text.