Abstract: A catalyst composition includes a zirconia support on which is dispersed a limited amount of ceria to provide a zirconia/dispersed ceria support, and a rhodium catalytic component. The ceria content of the zirconia support does not exceed about fifteen percent by weight based on the combined weight of ceria plus zirconia. The resultant catalyst composition enhances the efficiency of three-way conversion catalyst systems in which it is employed, possibly by promoting the water gas shift reaction and the steam reforming of hydrocarbon. The rhodium on zirconia/dispersed ceria support may be combined with a catalytically effective amount of a platinum catalytic component to provide an effective three-way conversion catalyst.

Abstract: A catalyst composition includes a catalytic material containing a platinum catalytic component dispersed on a bulk ceria and a palladium catalytic component; the palladium catalytic component may be dispersed either on the ceria or on another support, such as an activated alumina support. The catalytic material, which may include a refractory binder, such as alumina, may be dispersed as a washcoat on a suitable carrier, e.g., a cordierite honeycomb-type carrier having a plurality of fine gas flow passages extending therethrough. The bulk ceria may be stabilized with a zirconia stabilizer and/or a lanthana stabilizer. The catalyst composition has utility as an oxidation catalyst and as a three-way conversion catalyst.

Abstract: A self-cleaning diesel exhaust particulate filter is disclosed wherein burn-off of collected particulate matter is accomplished at certain exhaust gas temperatures, the filter being provided with a catalyst mixture consisting essentially of a platinum group metal and an alkaline earth metal oxide. The platinum group metal may be one or both of platinum and rhodium and the alkaline earth metal oxide may be magnesium oxide. The presence of the catalyst mixture serves to lower the temperature at which ignition of the collected particulates is initiated.

Abstract: H.sub.2 S formation by three way catalyst is suppressed by incorporating copper, nickel, manganese or iron oxides into a monolith section downstream of the three way catalyst.

Abstract: A catalyst composition comprises a carrier having a refractory metal oxide support coating thereon and a catalytic platinum group metal dispersed on the support coating. A major portion of the support coating is comprised of a conventional, first metal oxide such as stabilized gamma alumina and a minor portion is provided by a macroporous, second metal oxide such as cordierite. The second metal oxide is conveniently provided by comminuting finished catalyst production scrap. In the method of the invention particles of the first metal oxide are combined with particles of the second metal oxide to form the coating.

Abstract: A three-way catalyst of improved efficiency suitable for simultaneously oxidizing both gaseous hydrocarbons and carbon monoxide, while reducing nitrogen oxides is disclosed. The three-way catalyst includes alumina, a platinum group metal and a rare earth metal oxide having deposited thereon in intimate contact therewith a p-type metal oxide.

Abstract: A method of making a catalyst composition comprising an activated alumina coating stabilized against thermal degradation includes applying a coating of alumina having one or more platinum group metal catalytic components dispersed thereon onto a carrier substrate and calcining the coating. The calcined coating is then impregnated with a solution of a thermal stabilizer-precursor and calcined again to provide a thermal stabilizer in the alumina. Bulk ceria, optionally an aluminum-stabilized bulk ceria, may also be added to the composition, preferably at specified minimum levels, including a high purity bulk ceria on which one or more non-rhodium platinum group metal catalytic components, e.g., platinum, optionally, are dispersed. A separate aspect of the invention provides for a method of making a catalyst composition including dispersing one or more platinum group metal catalytic components on an activated alumina and calcining the combined alumina and platinum group metal catalytic components.

Abstract: A catalyst material comprises an aluminum-stabilized ceria which optionally may be combined with an activated alumina and may also comprise one or more platinum group metal catalytic components. A method of making the material includes impregnating bulk ceria or a bulk ceria precursor with an aluminum compound and calcining the impregnated ceria to provide an aluminum-stabilized ceria. The bulk ceria advantageously comprises a high purity (at least 90 weight percent CeO.sub.2) ceria and may be admixed with activated aluminia having one or more platinum group metal catalytic components dispersed thereon. The catalyst material may be coated onto a suitable carrier substrate and then calcined. Specified minimum levels of the aluminum-stabilized bulk ceria are advantageously employed in the catalyst materials of the invention. The bulk ceria may have one or more preferably non-rhodium platinum group metal catalytic components dispersed thereon, e.g.

Abstract: Three-way catalysts containing rhodium, rare earth oxide and platinum and/or palladium of improved durability, when subjected to exhaust gases containing excess oxygen, are formed, when the rhodium is segregated from the rare earth oxide, thereby preventing undesirable interactions between the rhodium and are earth oxide. The efficiency of the catalyst is optimized when the rhodium has an initial average particle size ranging from about 35 to about 80 .ANG. in diameter.

Abstract: A method for stabilizing alumina supports for metal catalysts by impregnating the support with an aqueous dispersion of a high molecular weight, water dispersible polyorganosiloxane and calcining.

Abstract: The invention relates to improved catalytic compositions for controlling gaseous contaminants from the combustion of carbonaceous fuels and, in particular, to three-way catalysts having improved ability to convert unburnt hydrocarbons, carbon monoxide and nitrogen oxides to less harmful forms in the presence of excess oxygen.

Abstract: Catalysts having three types of particles dispersed on a monolith have surprising oxidation and three-way activity even after exposure to temperatures above 1000.degree. C. The particle types are: (1) palladium dispersed on stabilized alumina; (2) ceria-containing promoter particles and (3) washcoat stabilization particles.

Abstract: Selective reduction of NO.sub.x with NH.sub.3 as well as decomposition of excess NH.sub.3 is provided over a wide temperature range by a platinum-gold catalyst.

Abstract: A novel process for the efficient, selective and steady conversion of n-alkenes, such as n-butylenes, to their skeletal isomers is disclosed. Catalysts and catalytic conditions are also disclosed.

Abstract: A catalytic promoting material is supported on a monolithic support member, of the type generally referred to as a "honeycomb" support, having longitudinal fluid flow channels extending through it. The catalytically promoting material is dispersed as a coating on the walls of the fluid flow channels which are nominally polygonal, preferably nominally square, in cross section profile so that the walls forming the flow channels can be made as thin as possible consistent with an acceptable thermal and mechanical strength. However, the juncture of the channel walls forming the flow channels are filleted to provide a concave profile, preferably one having an arcuate shape in cross section, so that the corners are "filleted" or "rounded", to subtend an appreciable segment of the nominal width of the channel wall. This prevents or at least reduces the accumulation of excess catalytic material which occurs in the sharp angular corners of prior art structures.

Abstract: Catalysts are made which have a catalytically-active composite containing a catalytically-promoting metal component and a high surface area, refractory oxide support, deposited on a macrosize carrier. The catalytically-active composite is made by combining a solution of a water-soluble, catalytically-promoting metal component with a finely divided, high area, refractory oxide which is sufficiently dry to absorb essentially all of said solution. The catalytically-promoting metal component of the resulting composite is converted to water-insoluble form while the composite is essentially devoid of unabsorbed solution. The composite is comminuted in the presence of an aqueous medium which is preferably acidic. The resulting slurry is used to deposit the catalytically-promoting metal-containing solids on the macrosize carrier, and the resulting material is dried and may be calcined.

Abstract: Catalytic compositions particularly useful in the production of hydrogen from methanol, especially by steam reforming, which comprises a mixture of zinc oxide, copper oxide, thorium oxide and aluminum oxide whereby the activity and activity maintenance of the catalytic composition is superior relative to a composition otherwise substantially the same but lacking thoria.

Abstract: Catalysts having good high temperature stability which are particularly useful for selected high temperature reactions are disclosed as are methods for their preparation and use. The catalytically-active materials include platinum group metal deposited on a catalytic slip or composite which contains a mixture of alumina, a rare earth metal oxide, and a metallic oxide wherein the metal is IVB, selected VIB metals, and mixtures thereof. The slips or carrier compositions are calcined at a temperature of at least 850.degree. C. before deposition of platinum group metal and characterized by having a surface area of at least 20 m.sup.2 /g after calcination at a temperature of 1200.degree. C. for two hours.

Abstract: Catalysts having good high temperature stability which are particularly useful for selected high temperature reactions are disclosed as are methods for their preparation and use. The catalytically-active materials include platinum group metal deposited on a catalytic slip or composite which contains a mixture of alumina and a mixture of IVB and selected VIB metal oxides. The slips or carrier compositions are calcined at a temperature of at least 850.degree. C. before deposition of platinum group metal and characterized by having a surface area of at least 20 m.sup.2 /g after calcination at a temperature of 1200.degree. C. for two hours.

Abstract: 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.