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US 9,751,080 B2Granted
PGM catalyst for treating exhaust gas
AssigneeJohnson Matthey Public Limited Company
InventorsJoseph Michael Fedeyko, Hai-Ying Chen, Paul Joseph Andersen
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Abstract
Provided are catalysts comprising a small pore molecular sieve embedded with PGM and methods for treating lean burn exhaust gas using the same.
Claims20
A catalyst article comprising:
- a. a substrate;
- and
- b. a PGM catalyst disposed on the substrate in a discrete outlet zone, said catalyst comprising
- i. aluminosilicate molecular sieve crystals having surfaces and porous networks, a mean crystalline size of about 0.01 to about 10 microns, a framework selected from CHA, RHO, LEV, AEI, ANA, LTA, DDR, PAU, UEI, and SOD, a silica-to-alumina ratio of about 8 to about 150, and an alkali content of no more than about 5 weight percent based on the total weight of the molecular sieve crystals;
- and
- ii. 0.1 to 5 weight percent palladium based on the total weight of the molecular sieve crystals, wherein a majority amount of said palladium is disposed in said porous networks relative to said surfaces, and
- c. an SCR catalyst disposed on the substrate in a discrete inlet zone, said SCR catalyst having either a molecular sieve promoted with iron and/or copper or vanadium on an alumina support.
4 more elements
A system for treating exhaust gas comprising:
- a. a reductant source;
- b. an upstream SCR catalyst;
- and
- c. a downstream PGM catalyst comprising
- i. aluminosilicate molecular sieve crystals having surfaces and porous networks, a mean crystalline size of about 0.01 to about 10 microns, a framework selected from CHA, RHO, LEV, AEI, ANA, LTA, DDR, PAU, UEI, and SOD, a silica-to-alumina ratio of about 8 to about 150, and an alkali content of no more than about 5 weight percent based on the total weight of the molecular sieve crystals;
- and
- d. 0.1 to 5 weight percent palladium based on the total weight of the molecular sieve crystals, wherein a majority amount of said palladium is disposed in said porous networks relative to said surfaces;
- wherein said SCR catalyst and said PGM catalyst are disposed on separate substrates;
- said reductant source, upstream SCR catalyst, and downstream catalyst are in fluid communication with each other and are arranged so that an exhaust gas stream flowing through the system contacts the reductant source prior to the upstream SCR catalyst and contacts the SCR catalyst prior to the downstream SCR catalyst.
6 more elements
Dependencies are inferred from the claim text.