| 摘要 |
PROBLEM TO BE SOLVED: To suppress the sulfur poisoning of a NOx occlusion and reduction type exhaust gas cleaning catalyst. SOLUTION: An exhaust gas cleaning catalyst comprises a carrier base material 2, a carrying layer 3 covering the surface of the carrier base material, and a Pt and NOx occlusion material carried on this carrying layer 3, wherein the carrying layer 3 has a double layer structure consisting of an upper layer 5 and a lower layer 4, and the concentration of Pt in the upper layer 5 is made to be higher than that of the lower layer 4. The concentration of Pt in the upper layer 5 is adjusted to 1.5 wt.% or more based on the weight of the carrying layer 3. In addition, the thickness of the upper layer 5 is made to be 10 to 20 μm. Such a structure enables more efftctent capture of SOx in the upper layer 5. |
