Diesel exhaust gas oxidation catalyst, and method for purifying diesel exhaust gas by using same

摘要

A diesel exhaust gas oxidation catalyst, which is configured to purify exhaust gas from a diesel engine, includes: an alumina-based carrier in which a content of alumina is 40 mass% or higher; Pt supported on the alumina-based carrier; Pd supported on the alumina-based carrier; and at least one type of added element that is selected from the group consisting of alkali metal elements and alkaline earth metal elements and that is supported on the alumina-based carrier. A supported quantity of the Pt is 0.1 to 5 parts by mass relative to 100 parts by mass of the alumina-based carrier. A molar ratio obtained by dividing a supported quantity of the Pd by the supported quantity of the Pt is 0.1 to 1.5. A molar ratio obtained by dividing a supported quantity of the added element by the supported quantity of the Pt is 1 to 12.