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AssigneeEngelhard Corporation
InventorsJordan K. Lampert, Michel Deeba, Robert J. Farrauto
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A catalyzed hydrocarbon trap material washcoat (20) used in a trap (10), which may be placed downstream of a conventional catalyst member (28), is useful for treating internal combustion engine (22) exhaust. Trap (10) traps hydrocarbons during cold operation periods and releases them for oxidation during higher-temperature operating periods. The material comprises palladium and silver dispersed on a high surface area metal oxide support and a zeolite material such as one or more of ZSM-5, Beta, Y, and other suitable zeolites. The trap material is efficiently made by combining in a single vessel the zeolite, the metal oxide support, and aqueous solutions of a palladium compound and a silver compound. Surprisingly, the intimate combination of silver with the palladium does not adversely affect catalytic efficiency of the palladium and provides advantageous results in enhancing catalytic oxidation of hydrocarbons desorbed from the trap (10) and coke which forms thereon.
A catalyzed hydrocarbon trap material comprising a mixture of (1) a particulate refractory inorganic oxide support having dispersed thereon a silver component and a catalytically effective amount of a palladium component, and (2) a particulate zeolite having a Si to Al atomic ratio of at least 10 and a pore aperture diameter of at least 4 Angstroms, the zeolite having dispersed thereon a silver component and a palladium component, the catalyzed hydrocarbon trap material being made by a process of
A catalyzed hydrocarbon trap material comprising a mixture of (1) a particulate refractory inorganic oxide support having dispersed thereon a silver component and a catalytically effective amount of a palladium component, and (2) a particulate zeolite having a Si to Al atomic ratio of at least 10 and a pore aperture diameter of at least 4 Angstroms, the zeolite having dispersed thereon a silver component and a palladium component.
Dependencies are inferred from the claim text.