Patent ID: 6251820
Filing Date: 2001-06-26
Classification: B01D,B01J,Y02T

Abstract:
A process for producing a catalyst for purifying an exhaust gas, comprising the steps of:preparing a suspension by dispersing a precursor powder in a solvent,the precursor powder including amorphous and homogeneous composite particles, and a catalytic noble metal element,the composite particles including a support component, and an NOx storage component,the support component including an oxide of metal being at least one element selected from the group consisting of group 3B elements, group 4A elements and group 4B elements in the periodic table of the elements,the NOx storage component including at least one element selected from the group consisting of alkali metals, alkaline-earth metals and rare-earth elements,the catalytic noble metal element being only in a state in which the catalytic noble metal element is involved homogeneously in the composite particles,the solvent being free from elution of the NOx storage component, preparing a slurry by mixing an organosol with the suspension,the organosol including an organic solvent, and an oxide sol including at least one oxide selected from the group consisting of oxides of aluminum (Al), oxides of silicon (Si) and oxides of zirconium (Zr), and dispersed in the organic solvent; anddepositing the slurry on a support substrate, and drying and thermally treating the support substrate, thereby forming a coating layer on the support substrate.