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US 3,993,572 AGranted
Rare earth containing catalyst composition
AssigneeEngelhard Minerals & Chemicals Corporation
InventorsSaul G. Hindin, Joseph C. Dettling
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AssigneeEngelhard Minerals & Chemicals Corporation
InventorsSaul G. Hindin, Joseph C. Dettling
Estimating the term…
Catalysts suitable for promoting selected oxidation and reduction reactions; especially for eliminating or substantially reducing pollutants in waste gas streams such as automobile exhaust, or nitric acid plant tail gas, are described, as are processes for their preparation and use. The catalysts contain platinum group metal, rare earth metal and alumina components which may be supported on relatively catalytically inert carriers, for instance, honeycombs. The catalysts can be prepared, for example, by pre-calcining a mixture of alumina and rare earth metal oxide, e.g., ceria, at a temperature of at least about 750.degree. C. to obtain a catalytically-active material; coating a relatively inert support, if such is used, with an aqueous slurry of the calcined material; calcining the composite, adding platinum group metal thereto and drying.
A composition consisting essentially of a relatively catalytically-inert, solid support having coated thereon a minor amount of a catalytically-active composite consisting essentially of a catalytically-effective amount of a platinum group metal selected from the group consisting of platinum, palladium, ruthenium, iridium and rhodium, added to an admixture of a rare earth metal oxide and alumina, said admixture containing alumina in an amount in the range of 70-99% by weight and selected from the group consisting of .gamma.-alumina, .eta.-alumina, .kappa.-alumina and .delta.-alumina and containing a rare earth metal oxide in an amount in the range of 1-30% by weight and selected from the group consisting of cerium oxide, lanthanum oxide, samarium oxide and praseodymium oxide, said admixture having a relatively high surface area of at least about 75 m.sup.2 per gram and having been derived from alumina or an aluminum compound and from said rare earth metal oxide or a compound of said rare earth metal which has been calcined at a temperature of at least 750.degree. C. to yield said alumina and said rare earth metal oxide.
Dependencies are inferred from the claim text.