| 摘要 |
PROBLEM TO BE SOLVED: To further reduce the discharge of particulates by improving heat resistance. SOLUTION: This catalyst is composed of the first coating layer 2 carrying Pt 4 and the second layer 3 carrying no Pt 4, and a layer thickness of the first coating layer 2 is kept in 1/10 to 1/5 of total layer thickness. A grain size of the Pt 4 is made larger compared with the case when the Pt 4 is deposited on a conventional mono coating layer by depositing the Pt 4 in high density on the first coating layer 2 thin in thickness. Therefore, a sintering of the Pt due to thermal history is hardly caused and durability is improved. |
