Abstract: A palladium three-way catalyst is supported on a unique ceria-lanthana-alumina support where the alumina content is lower than previously believed necessary to maintain catalyst activity. Preferably the ceria and lanthana constitute the major proportion of the support.

Abstract: This invention relates to an improved catalytic composite for treating an exhaust gas comprising a first support which is a refractory inorganic oxide, having dispersed thereon at least one oxygen storage component and at least one noble metal component and having dispersed immediately thereon an overlayer comprising lanthanum oxide and optionally a second support which is a refractory inorganic oxide. The first and second support may be selected from the group consisting of alumina, silica, titania, zirconia and aluminosilicates with alumina being preferred. Additionally, the noble metal component may be selected from the group consisting of platinum, palladium, rhodium, ruthenium and iridium. The oxygen storage component is an oxide of a metal which includes cerium, iron, nickel, cobalt lanthanum, neodymium, praesodymium, etc. and mixtures thereof. This invention also relates to a process for treating automotive exhaust comprising contacting the exhaust with the catalytic composite described above.

Abstract: A three-way layered catalyst for use in a stoichiometric air/fuel ratio system comprising an alumina support having deposited thereon the catalyst materials platinum, palladium and rhodium and having a first layer of platinum positioned at the support surface, a second layer of catalyst material selected from the group consisting of rhodium and a mixture of palladium and rhodium adjacent to and radially inward of the first layer with palladium inward of and adjacent to said second layer where the catalyst material of such layer is rhodium. Cerium oxide may be added to the support for improved performance.

Abstract: A layered catalyst having significantly improved performance characteristics including greater resistance to poisoning and sintering in automotive exhaust comprising an alumina support having a first layer of platinum positioned at the support surface and penetrating the body thereof to a desired depth with a second layer of at least one of the catalytically active materials selected from the group consisting of rhodium and palladium, the second layer being adjacent to the first layer and penetrating the body of the support for a depth beyond that of the first layer, maximum concentration of platinum being in the first layer together with minimum concentration of the catalytically active materials, and minimum concentration of platinum with maximum concentration of the catalytically active materials being in the second layer.

Abstract: A three-way layered catalyst adapted for use in a system operating at about the stoichiometric air/fuel ratio having significantly improved resistance to poisoning in automotive exhaust comprising an alumina support having a first layer of the catalyst material platinum positioned at the support surface and penetrating the body thereof to a desired depth with an inner second layer of the catalyst material rhodium, the second layer being adjacent to the first layer and penetrating the body of the support, the maximum concentration of platinum being at or near the surface of the support with the minimum concentration of rhodium in the first layer being at or close to the surface and increasing in concentration to a maximum to define the boundary between the first and second layers, the concentrations of platinum and rhodium decreasing inwardly from the boundary with the greater portion of rhodium being in the second layer.

Abstract: This invention relates to oxidation catalysts wherein the catalytically active metallic material has an impregnation depth of at least 90 microns up to about 250 microns on the porous support which has a surface area of at least 100 m.sup.2 /g. up to about 250 m.sup.2 /g. and a pore structure characterized by a macropore volume of at least 0.020 cm.sup.3 /g. and a macropore radius greater than about 10,000 A.degree., the maximum value for macropore volume being that at which the catalyst is unable to sustain the load and vibration forces to which it is subjected in the converter.

Abstract: Sulfate absorbent calcium hydroxide is dispersed in a binder and pelletized. The pellets are exposed to carbon dioxide at elevated temperatures to convert at least a portion of the calcium hydroxide to calcium carbonate. Pellets so treated are suitable for prolonged use in fixed volume sulfur oxide and sulfate scrubber vessels.

Abstract: This invention relates to oxidation catalysts wherein the catalytically active metallic material has an impregnation depth of at least 90 microns up to about 250 microns on the porous support which has a surface area of at least 100 m.sup.2 /g. up to about 250 m.sup.2 /g. and a pore structure characterized by a macropore volume of at least 0.020 cm.sup.3 /g. up to about 0.200 cm.sup.3 /g. and a macropore radius greater than about 10,000 A.