High temperature catalyst compositions for internal combustion engine
This patent describes a catalyst effective at least for oxidation of carbon monoxide and unburned hydrocarbons in an exhaust stream, the catalyst remaining effective after exposure to a temperature greater than 1000/sup 0/C. The catalyst comprises particles from each of the following three classes dispersed on a ceramic monolithic substrate: (a) stabilized gamma alumina support particles having palladium dispersed thereon, the gamma alumina support particles being stabilized by a method selected from the group consisting of: (i) incorporation of a combination of lanthana and baria into the particles and (ii) impregnation of the particles with an aqueous dispersion of a high molecular weight polyorganosiloxane followed by heating to a temperature which is effective to decompose the polyorganosiloxane; (b) promoter particles effective for promotion of combustion of carbon monoxide, the promoter consisting essentially of an oxide selected from the group consisting of bulk ceria, bulk zirconia and mixtures thereof; and (c) washcoat stabilization particles consisting essentially of a mixed oxide selected from the group consisting of cordierite, mullite, and magnesium aluminum titanate.
- Assignee:
- Engelhard Corp., Menlo Park, NJ
- Patent Number(s):
- US 4624940
- OSTI ID:
- 7035937
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
330100* -- Internal Combustion Engines
330702 -- Emission Control-- Carbon Monoxide
330704 -- Emission Control-- Hydrocarbons
500200 -- Environment
Atmospheric-- Chemicals Monitoring & Transport-- (-1989)
54 ENVIRONMENTAL SCIENCES
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CATALYST SUPPORTS
CATALYSTS
CATALYTIC CONVERTERS
CERAMICS
CHALCOGENIDES
CHEMICAL COMPOSITION
CHEMICAL REACTIONS
ENGINES
EQUIPMENT
EXHAUST GASES
FLUIDS
GASEOUS WASTES
GASES
HEAT ENGINES
HYDROCARBONS
IMPREGNATION
INTERNAL COMBUSTION ENGINES
LANTHANUM COMPOUNDS
LANTHANUM OXIDES
ORGANIC COMPOUNDS
OXIDATION
OXIDES
OXYGEN COMPOUNDS
PALLADIUM COMPOUNDS
POLLUTION CONTROL EQUIPMENT
RARE EARTH COMPOUNDS
STABILIZATION
SUBSTRATES
TRANSITION ELEMENT COMPOUNDS
VERY HIGH TEMPERATURE
WASTES
ZIRCONIUM COMPOUNDS
ZIRCONIUM OXIDES