| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an exhaust gas treatment catalyst with improved durability of a noble metal and capable of adsorbing NOx even at a high temperature and solving sulfur-poisoning at a low temperature even if a strongly alkaline substance is used. <P>SOLUTION: The catalyst comprises a powder composed of a porous material with a specific surface area of 150 m<SP>2</SP>/g or more which carries Ce and Pt with a Pt dispersion degree of not lower than 70% and not lower than 50% before firing at 700°C in air and after sintering, respectively. The powder shows no diffraction peak attributed to the Pt (311) face at a diffraction angle 2θ=81.37±0.2° by X-ray diffractometry using CuK α-beam after the firing or the powder has a decrease ratio R of the Pt dispersion degree after firing to that before firing is less than 40%, preferably less than 30%. <P>COPYRIGHT: (C)2004,JPO |
