| 摘要 |
PROBLEM TO BE SOLVED: To provide an exhaust gas purification catalyst having an effectively improved OSC function of a whole catalyst, while maintaining a high NOx purification function.SOLUTION: An exhaust gas purification catalyst disclosed herein includes a substrate 10 and a catalyst coating layer 30 formed on a surface of the substrate 10. The catalyst coating layer 30 is formed into a layered structure having upper and lower layers, with a lower layer 50 being closer to the surface of the substrate 10 and an upper layer 40 being relatively remote therefrom. The catalyst coating layer 30 includes Rh and Pd as noble metal catalysts, and also includes an OSC material having an oxygen storage capacity as a support. The Rh is disposed in the upper layer 40 of the catalyst coating layer 30, and the Pd is disposed in both of the upper layer 40 and the lower layer 50 of the catalyst coating layer 30. At least a portion of the Pd in the upper layer 40 and in the lower layer 50 is supported on the OSC material. A mass ratio of the Pd disposed in the upper layer 40 to the Pd disposed in the lower layer 50 is ≤0.4. |
