Abstract: A catalyst which purges a diesel engine exhaust gas of HC, CO, and SOF and reduces the emission of particulates as well and a method for the production thereof are provided. The catalyst for purifying a diesel engine exhaust gas has deposited on a refractory three-dimensional structure a catalyst component comprising silica-alumina supporting at least one noble metal selected from the group consisting of platinum, palladium, and rhodium and zeolite. This catalyst is produced by adding a noble metal component into a slurry of silica-alumina thereby inducing chemical adsorption, then adding zeolite to the resultant mixture thereby obtaining a mixed slurry of a noble metal-supporting silica-alumina and zeolite, dipping a refractory three-dimensional structure in the slurry thereby inducing deposition of the catalyst component, and subsequently calcining the resultant composite.

Abstract: Temperature range enabling combustion of high concentration hydrocarbon is enlarged, or high temperature gas is rapidly supplied to a latter part catalyst. Provided is a method for purification of exhaust gas from an internal combustion engine, by using a catalyst for increasing temperature of exhaust gas from an internal combustion engine, wherein hydrocarbon from 1,000 to 40,000 ppm by volume, as converted to methane, to the exhaust gas, is introduced at the upstream side of the catalyst for increasing temperature, along flow of the exhaust gas inside a passage of exhaust gas from the internal combustion engine.

Abstract: An exhaust-gas-purifying catalyst is made by depositing on a support iridium serving as a catalyst active substance, sulfur for improving the catalyst activity of iridium and, if necessary, platinum. The sulfur is preferably contained as a sulfate. The exhaust-gas-purifying process of the present invention is a process in which exhaust gas from an internal combustion engine is allowed to pass through the exhaust-gas-purifying catalyst with the exhaust-gas temperature being set in the range of 200° C. to 700° C. at the inlet of the exhaust-gas-purifying catalyst. The above-mentioned composition and process provide an activity for purifying exhaust gas, especially for eliminating nitrogen oxides in an oxidizing atmosphere, in a wide temperature range, allow high heat-resistance and durability, and consequently, are superior in practical use.

Abstract: A catalyst which is capable of decomposing and allaying particularly NOx among other harmful components in the diesel engine exhaust gas and, at the same time, depriving by combustion the exhaust gas of carbonaceous particulates, unburned hydrocarbons, and carbon monoxide and a method for purifying the diesel engine exhaust gas by the use of this catalyst are provided. The catalyst for the decomposition of the nitrogen oxides has a refractory three-dimensional structure coated with a copper-containing zirconia powder having deposited copper and the catalytically active oxide of at least one metal selected from the group consisting of tungsten, gallium, nickel, manganese, iron, and cobalt on a zirconia powder. The method for purifying the diesel engine exhaust gas uses the catalyst.

Abstract: A purifying catalyst for the exhaust gas from the internal combustion engine of an automobile, for example, is disclosed which excels in the purifying ability in quick response to the atmosphere of the exhaust gas largely varying with changes in the operating condition of the engine involving such phases as idling, acceleration, constant-speed drive, and deceleration. The purifying catalyst contains rhodium, palladium, a cerium compound, and a refractory inorganic oxide as catalytic components carried on a refractory carrier and comprises at least two catalyst layers, namely a catalyst layer containing the cerium compound and a catalyst layer containing palladium.