초록 ▼

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

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.

대표청구항 ▼

[ What is claimed is:] [1.] A process for purifying an exhaust gas from a lean-burn engine comprising sulfur oxides, carbon monoxide, hydrocarbons and nitrogen oxides, the process comprising:bringing said exhaust gas into contact with an exhaust gas purifying catalyst comprising:a support comprising

[ What is claimed is:] [1.] A process for purifying an exhaust gas from a lean-burn engine comprising sulfur oxides, carbon monoxide, hydrocarbons and nitrogen oxides, the process comprising:bringing said exhaust gas into contact with an exhaust gas purifying catalyst comprising:a support comprising a solid solution formed by dissolving an aqueous solution comprising at least one element selected from the group consisting of alkali metals and alkaline-earth metals in titania to form impregnated titania and burning said impregnated titania at a temperature greater than 600.degree. C.; anda noble metal catalyst ingredient loaded on the support;wherein (1) under a lean-burn atmosphere in which oxygen concentrations are above a neutral point that is required for oxidizing components to be oxidized in said exhaust gas, nitrogen oxides and sulfur oxides in said exhaust gas are adsorbed to said solid solution; (2) said exhaust gas is periodically adjusted from lean-burn to fuel-rich, providing a reduction atmosphere in which oxygen concentrations are not greater than said neutral point; and (3) under said reduction atmosphere, nitrogen oxides adsorbed to said solid solution are chemically reduced by a reaction with hydrocarbons and carbon monoxide in said exhaust gas and sulfur oxides adsorbed to said solid solution are released.