Effects of Pt and Pd impregnation on the performance and durability of automobile exhaust oxidizing catalysts

Conference · Mon Aug 01 04:00:00 EDT 1977 · Prepr., Div. Pet. Chem., Am. Chem. Soc.; (United States)

OSTI ID:6791900

Summers, J C; Hegedus, L L

Since the fall of 1974, catalysts have been employed commercially to oxidize the carbon monoxide and hydrocarbon emissions from most automobiles sold in the United States. Although this application of catalytic technology has been remarkably successful in reducing automobile pollution, there is a continued interest in exploring ways of preparing catalysts having improved performance and durability characteristics. Catalyst poisoning in automobile exhaust has recently been reviewed by both for pellet-type and monolithic catalysts. This work deals only with pellet-type supported catalysts. To assess the importance of metal location in the pellets, five alumina-supported catalysts were prepared and tested. Both the initial performance and poisoning and sintering durability of oxidation catalysts are very strongly influenced by the manner in which they are impregnated by a given amount of Pt and Pd. This was observed both for the high temperature, diffusion influenced behavior of the catalysts and also for their lightoff performance, and holds both for HC and CO oxidation. In particular, the results showed that clear improvements, both in steady state and lightoff performance, are possible if the catalyst pellets are impregnated by an outer shell of Pt and an inner shell of Pd. This configuration, then, appears to be the best use of a given amount of Pt and Pd in automobile exhaust oxidation catalysis, at least under the conditions covered by these experiments.

• Research Organization: General Motors Research Labs., Warren, MI
• OSTI ID: 6791900
• Conference Information: Journal Name: Prepr., Div. Pet. Chem., Am. Chem. Soc.; (United States) Journal Volume: 22:4
• Country of Publication: United States
• Language: English

Related Subjects

33 ADVANCED PROPULSION SYSTEMS
330702* -- Emission Control-- Carbon Monoxide
330704 -- Emission Control-- Hydrocarbons
AIR POLLUTION CONTROL
AUTOMOBILES
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CATALYSTS
CATALYTIC CONVERTERS
CHALCOGENIDES
ELEMENTS
EQUIPMENT
EXHAUST GASES
FABRICATION
GASEOUS WASTES
HYDROCARBONS
METALS
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PALLADIUM
PELLETS
PERFORMANCE TESTING
PLATINUM
PLATINUM METALS
POLLUTION CONTROL
POLLUTION CONTROL EQUIPMENT
SINTERING
TESTING
TRANSITION ELEMENTS
VEHICLES
WASTES