Engine exhaust catalysts containing palladium-gold
AssigneeNanostellar, Inc.
InventorsKyle L. Fujdala, Timothy J. Truex
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Abstract
An emission control catalyst that exhibits improved CO and HC reduction performance includes a supported platinum-based catalyst, and a supported palladium-gold catalyst. The two catalysts are coated onto different layers, zones, or monoliths of the substrate for the emission control catalyst such that the platinum-based catalyst encounters the exhaust stream before the palladium-gold catalyst. Zeolite may be added to the emission control catalyst as a hydrocarbon absorbing component to boost the oxidation activity of the palladium-gold catalyst.
Claims20
An emission control catalyst for treating an engine exhaust comprising a first catalytically active zone and a second catalytically active zone, wherein the first catalytically active zone is positioned to encounter the engine exhaust before the second catalytically active zone, and wherein the first catalytically active zone includes a first supported catalyst comprising platinum-containing metal particles supported on an oxide carrier and the second catalytically active zone includes a second supported catalyst consisting essentially of palladium-gold metal particles supported on an oxide carrier, wherein the second supported catalyst has palladium to gold weight ratio range of about 0.5:1 to about 1:0.5.
An emission control catalyst for treating an engine exhaust comprising a substrate having a first washcoat metal particles comprising platinum and a second washcoat containing metal particles consisting essentially of palladium and gold in close contact, wherein the first washcoat is positioned to encounter the engine exhaust prior to the second washcoat, wherein the second supported catalyst has a palladium to gold weight ratio range of about 0.5:1 to about 1:0.5.
An emission control catalyst comprising a first catalyst comprising platinum-containing metal particles, a second catalyst comprising palladium-gold containing metal particles other than platinum-palladium-gold metal particles, and physically separate zones for each of the first catalyst and the second catalyst, wherein the second supported catalyst has a palladium to gold weight ratio range of about 0.5:1 to about 1:0.5.
Dependencies are inferred from the claim text.