| 摘要 |
<P>PROBLEM TO BE SOLVED: To further suppress particle growth of a carried noble metal and also highly suppress movement of the noble metal between layers. <P>SOLUTION: A catalyst for cleaning an exhaust gas comprises a lower catalyst layer 2 carrying at least one kind selected from the group consisting of Pt and Pd on a carrier containing ceria oxide and an upper catalyst layer 3 formed on the lower catalyst layer 2 wherein the lower catalyst layer 2 includes ceria oxide of 90 wt% or more. In the lower catalyst layer 2, since a ratio of the noble metal which moves from ceria oxide to other oxide included at less than 10 wt% there into is significantly small, the particle growth of the noble metal can effectively be suppressed. In addition, the movement from the lower catalyst layer 2 to the upper catalyst layer 3 is also suppressed, a malfunction such as alloying with the noble metal present in the upper layer 3 can be suppressed. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
