Three-way catalyst for lean operating engines
An improved three-way catalyst is described suitable for simultaneously oxidizing both gaseous hydrocarbons and carbon monoxide while reducing nitrogen oxides. The catalyst comprises a washcoat comprising rhodium dispersed on particles of gamma alumina; an amount of a rare earth oxide effective for enhancing oxidation of carbon monoxide; and a second platinum group metal selected from the group consisting of platinum, palladium and mixtures thereof. The second platinum group metal is dispersed on particles selected from the group consisting of particles of rare earth oxide. Particles of alumina and particles of gamma alumina are stabilized with rare earth oxide and mixtures thereof. The improvement comprises a substantial portion of the rhodium being dispersed on particles which are substantially rare earth oxide free.
- Assignee:
- Engelhard Corp., Menlo Park, NJ
- Patent Number(s):
- US 4675308
- OSTI ID:
- 6428727
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
330701* -- Emission Control-- Nitrogen Oxides
330702 -- Emission Control-- Carbon Monoxide
330704 -- Emission Control-- Hydrocarbons
AIR POLLUTION CONTROL
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CATALYSTS
CATALYTIC CONVERTERS
CHALCOGENIDES
CHEMICAL REACTIONS
CONTROL
DISPERSIONS
ENGINES
EQUIPMENT
HEAT ENGINES
HYDROCARBONS
INTERNAL COMBUSTION ENGINES
MIXTURES
NITROGEN COMPOUNDS
NITROGEN OXIDES
ORGANIC COMPOUNDS
OXIDATION
OXIDES
OXYGEN COMPOUNDS
PALLADIUM COMPOUNDS
PARTICLES
PARTICULATES
PLATINUM COMPOUNDS
POLLUTION CONTROL
POLLUTION CONTROL EQUIPMENT
RARE EARTH COMPOUNDS
REFRACTORY METAL COMPOUNDS
RHODIUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS