| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a composition having high specific surface area stability and oxygen storing potential stability and usable at a high temperature. <P>SOLUTION: The composition is based on cerium oxide and zirconium oxide of at least one cerium/zirconium atom ratio and properly based on yttrium, scandium or rare earth metal oxide and the composition exhibits a specific surface area of at least 35 m<SP>2</SP>/g after calcination at 900°C for 6 h and oxygen storing potential of at least 1.5 ml/g O<SB>2</SB>at 400°C. The composition is manufactured by mixing a cerium compound, a zirconium compound and properly yttrium, scandium or rare earth metal compound, heating the mixture and calcining an obtained precipitate. The mixture is prepared by using a zirconium solution and an amount of a base required to reach an equivalence point when the solution is subjected to acid/base titration satisfies a molar ratio condition of OH<SP>-</SP>/Zr ≤ 1.65. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
