An exhaust gas-purifying catalyst includes a substrate, and a catalytic layer facing the substrate and including a precious metal, alumina, an oxygen storage material, and a sulfate of an alkaline-earth metal having an average particle diameter falling within a range of 0.01 to 0.70 μm, the average particle diameter being obtained by observation using a scanning electron microscope. Another exhaust gas-purifying catalyst includes a substrate, and a catalytic layer formed on the substrate using slurry containing a precious metal, alumina, an oxygen storage material, and a sulfate of an alkaline-earth metal having an average particle diameter falling within a range of 0.01 to 0.70 μm, the average particle diameter being obtained by observation using a scanning electron microscope.

Exhaust gas purifying catalyst

A catalyst for purifying carbon monoxide, hydrocarbons and nitrogen oxides in exhaust gases at the stoichiometric point or in oxygen-rich atmospheres, is disclosed, and it includes a support in which at least one element selected from the group consisting of alkali metals, alkaline-earth metals and rare-earth elements including La is dissolved in titania to form a solid solution, and a noble metal catalyst ingredient loaded on the support. A process for purifying, by bringing the exhaust gases into contact with the catalyst, is also disclosed.

Process for purifying exhaust gases

An exhaust gas purification catalyst includes: a lower catalyst layer that contains a ceria-zirconia mixed oxide having 50 to 70 mass% of CeO 2 and 5 mass% or more of Pr 2 O 3 and carries at least one of Pt and Pd; and an upper catalyst layer that contains at least zirconia and carries at least Rh, wherein the total amount of CeO 2 per liter of the carrier base is 15 to 30 g. Because the amount of CeO 2 is small, formation of H 2 S is suppressed and a high capability of adsorbing and releasing oxygen is brought out in spite of the small amount of CeO 2 .

Exhaust gas purification catalyst

A catalyst for purifying an exhaust gas to remove nitrogen oxides, carbon monoxide and hydrocarbons from an oxygen-rich exhaust gas containing nitrogen oxides, carbon monoxide and hydrocarbons comprising (i) a zeolite having an SiO2/Al2O3 mole ratio of at least 15 and (ii) (a) cobalt, (b) a rare earth metal and (c) silver, or nickel and/or zinc, or platinum and/or manganese, or copper and/or rhodium, incorporated thereinto.

Catalyst for purifying exhaust gas

A process for purifying an exhaust gas comprising carbon monoxide, hydrocarbons, nitrogen oxides, and sulfur oxides by periodically adjusting exhaust gas conditions from lean-burn to fuel-rich and by using a catalyst comprising an alumina support with lithium dissolved therein to form a solid solution, at least one first ingredient selected from the group consisting of platinum and palladium loaded on the alumina support, and at least one second ingredient selected from the group consisting of alkali elements, alkaline-earth elements, and rare-earth elements loaded on the support. Sulfates formed from sulfur oxides in the exhaust gas are decomposed by the lithium under the fuel-rich conditions to inhibit the alumina support from being acidified.

Catalyst for purifying exhaust gases and process for purifying exhaust gases

PURPOSE: To increase high temp. durability of a catalyst by preparing a slurry by adding activated alumina contg. the platinum group element, selenium oxide and barium nitrate, etc., sticking the slurry on a carrier having an integrated structure and thereafter calcining it. CONSTITUTION: The slurry contg. activated alumina contg. platinum group element, selenium oxide and barium nitrate, and/or barium formate is prepared. The catalyst for cleaning exhaust gas is produced by sticking the slurry on the carrier having the integrated structure and thereafter calcining it. Said carrier consists of refractory metal oxide or durable metal and its monolithic or three-dimensional network structure is preferable as the form of the carrier. Selenium oxide content is preferably 10W200g/1l catalyst obtd. COPYRIGHT: (C)1988,JPO&Japio

Masaki Funabiki

Papers

Production of catalyst for cleaning exhaust gas