Three-way conversion catalysts: part of the new emission control system

Conference · Sat Jan 01 04:00:00 EST 1977

OSTI ID:7215834

Mooney, J J; Thompson, C E; Dettling, J C

When the three-way conversion (TWC) catalysts were aged on representative 1977 unleaded commercial fuel, they had higher conversion efficiencies and improved durability than catalysts aged on modified 1975 FTP specification fuel containing approximately 0.025 g/gal Pb and low levels of phosphorus. As the rhodium content was increased in a series of platinum-rhodium TWC catalysts, the maximum conversion efficiency and durability increased, and the mine recovery ratio of Pt/Rh was found to be most susceptible to lead poisoning. However, good NO/sub x/ efficiencies can be obtained from mine recovery ratio Pt/Rh TWC catalysts after 25,000 miles of engine aging. It is shown that improvements in catalyst formulations containing mine recovery ratio Pt/Rh resulted in higher conversion efficiencies. Monolithic TWC catalysts require approximately the same total precious metal as current oxidation catalysts. Particulate TWC catalysts show beneficial effects in increasing the precious metal loading above 15 grams/cubic foot.

• OSTI ID: 7215834
• Report Number(s): CONF-770205-27
• Country of Publication: United States
• Language: English

Related Subjects

33 ADVANCED PROPULSION SYSTEMS
330701* -- Emission Control-- Nitrogen Oxides
330702 -- Emission Control-- Carbon Monoxide
330704 -- Emission Control-- Hydrocarbons
AUTOMOBILES
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CATALYSTS
CATALYTIC CONVERTERS
CHALCOGENIDES
ELEMENTS
EQUIPMENT
EXHAUST GASES
FUELS
GASEOUS WASTES
GASOLINE
HYDROCARBONS
LEAD COMPOUNDS
METALS
NITROGEN COMPOUNDS
NITROGEN OXIDES
ORGANIC COMPOUNDS
ORGANOMETALLIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PETROLEUM PRODUCTS
PLATINUM
PLATINUM METALS
POLLUTION CONTROL EQUIPMENT
REFRACTORY METALS
RHODIUM
TEL
TESTING
TRANSITION ELEMENTS
UNLEADED GASOLINE
VEHICLES
WASTES