Three-way catalyst for lean exhaust systems

Patent · Tue Jul 07 04:00:00 EDT 1987

OSTI ID:6256047

Wan, C Z; Dettling, J C; Jagel, K I

An improved three-way catalyst, is described suitable 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. The second platinum group metal is dispersed on particles selected from the group consisting of particles of rare earth oxide, particles of alumina, particles of gamma alumina stabilized with rare earth oxide and mixtures; the improvement comprises a substantial portion of the rhodium dispersed on particles which are substantially rare earth oxide free. The substantial portion of the rhodium is dispersed as crystallites having an initial particle size greater than about 2 nm.

• Assignee: Engelhard Corp., Menlo Park, NJ
• Patent Number(s): US 4678770
• OSTI ID: 6256047
• Country of Publication: United States
• Language: English

Related Subjects

33 ADVANCED PROPULSION SYSTEMS
330702* -- Emission Control-- Carbon Monoxide
330704 -- Emission Control-- Hydrocarbons
500200 -- Environment
Atmospheric-- Chemicals Monitoring & Transport-- (-1989)
54 ENVIRONMENTAL SCIENCES
AIR POLLUTION CONTROL
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CATALYSTS
CATALYTIC CONVERTERS
CATALYTIC EFFECTS
CHALCOGENIDES
CHEMICAL REACTIONS
CONTROL
DISPERSIONS
ELEMENTS
ENGINES
EQUIPMENT
EXHAUST SYSTEMS
HEAT ENGINES
HYDROCARBONS
INTERNAL COMBUSTION ENGINES
METALS
MIXTURES
NITROGEN COMPOUNDS
NITROGEN OXIDES
ORGANIC COMPOUNDS
OXIDATION
OXIDES
OXYGEN COMPOUNDS
PALLADIUM COMPOUNDS
PARTICLE SIZE
PARTICLES
PARTICULATES
PLATINUM COMPOUNDS
PLATINUM METALS
POLLUTION CONTROL
POLLUTION CONTROL EQUIPMENT
RARE EARTH COMPOUNDS
RHODIUM
SIZE
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS