초록 ▼

An oxidation catalyst that efficiently promotes oxidation of NO to NO2 even in a low temperature range, and an exhaust-gas purification system and method that efficiently removes exhaust-gas components even in a low temperature range are provided. This invention provides an oxidation catalyst compri

An oxidation catalyst that efficiently promotes oxidation of NO to NO2 even in a low temperature range, and an exhaust-gas purification system and method that efficiently removes exhaust-gas components even in a low temperature range are provided. This invention provides an oxidation catalyst comprising platinum and palladium as catalytically active components, which promotes oxidation of nitrogen monoxide to nitrogen dioxide, wherein the oxidation catalyst comprises 1 to 55 parts by weight of the palladium relative to 100 parts by weight of the platinum.

대표청구항 ▼

What is claimed is: 1. A process for purifying an exhaust gas discharged from an internal-combustion engine, comprising (1) a step for converting nitrogen monoxide in the exhaust gas to nitrogen dioxide by bringing the above exhaust gas into contact with an oxidation catalyst comprising platinum and

What is claimed is: 1. A process for purifying an exhaust gas discharged from an internal-combustion engine, comprising (1) a step for converting nitrogen monoxide in the exhaust gas to nitrogen dioxide by bringing the above exhaust gas into contact with an oxidation catalyst comprising platinum and palladium as catalytically active components, which promotes oxidation of nitrogen monoxide to nitrogen dioxide, wherein the oxidation catalyst comprises 1 to 55 parts by weight of the palladium relative to 100 parts by weight of the platinum, and (2) a step for reducing the nitrogen oxides in the exhaust gas by bringing the exhaust gas obtained in the step (1) into contact with a NOX reduction catalyst in the presence of a reducing agent, wherein x is 1 or 2.