摘要 |
PURPOSE:To obtain an exhaust gas purifying catalyst having high oxidizing activity to harmful components in exhaust gas from an internal combustion engine of a car in a low temp. region and capable of reducing cold HC discharged immediately after the start of an engine. CONSTITUTION:An exhaust gas purifying catalyst is composed of multi- component composite oxide containing palladium, manganese and cerium represented by general formula PdaMnbCecXdYeOf (X is at least one kind of an element selected from a group consisting of potassium, rubidium, cesium and barrium, Y is at least one kind of an element selected from the group consisting of copper, magnesium, zinc, germanium, silicon, nickel, silver, chromium, lanthanum, strontium and zirconium, a shows the wt.% of palladium and is a=0.01-3, b, c, d, e and f shows atomic ratios of respective components and, when b is 10, c is 0.1-10, d is 0.01-5 and e is 0.01-5 and f is the number of oxygen atoms necessary for satisfying the valencies of respective components). |