| 摘要 |
PROBLEM TO BE SOLVED: To provide an exhaust gas purifying catalyst for controlling the NOx adsorption amount in an exhaust gas low temperature area and purifying the adsorbed NOx almost completely, by which the NOx is not exhausted in an exhaust gas high temperature area. SOLUTION: In an exhaust gas purifying catalyst provided with a solid acid carrying a catalyst metal and CeO2 , the average crystal diameter D of CeO2 to be used for D>=13.0 nm is used. CeO2 contains Zr, and its content e1 is e1 <=9.0 wt.%, and as the catalyst metal, Pt is used, and as the solid acid, zeolite is used. Pt carrying zeolite is prepared by using the ion exchange method, the vacuum plating method (PVD), the impregnation method or the like in which Pt is carried on zeolite. |
