| 摘要 |
<P>PROBLEM TO BE SOLVED: To obtain high exhaust gas purification performance with a small amount of catalytic metal, and to suppress deterioration of catalytic activity under high temperature. <P>SOLUTION: A catalyst for purifying exhaust gas includes a catalyst layer where an A particle component and a B particle component coexist on a carrier. The A particle component is composed of a catalytic metal-doped CeZr-based composite oxide powder and has a particle size distribution with a peak in a particle size range equal to or more than 100 nm and equal to or less than 300 nm, and the mass ratio, CeO<SB POS="POST">2</SB>/(CeO<SB POS="POST">2</SB>+ZrO<SB POS="POST">2</SB>), of a CeZr-based composite oxide is equal to or more than 30% and equal to or less than 75%. The B particle component is composed of at least one selected from the group consisting of an activated alumina powder, a Zr-based oxide-supported alumina powder, and a catalytic metal-undoped CeZr-based composite oxide powder, and at least a part of the B particle component has a particle size larger than that of the A particle component. <P>COPYRIGHT: (C)2012,JPO&INPIT |
