초록 ▼

A catalyst for purifying exhaust gases includes a porous support; a cerium oxide or a solid solution of a cerium oxide and a zirconium oxide in a state of mutual solid solution, loaded on the porous support; and a noble metal element loaded on the porous support. The cerium oxide or the solid soluti

A catalyst for purifying exhaust gases includes a porous support; a cerium oxide or a solid solution of a cerium oxide and a zirconium oxide in a state of mutual solid solution, loaded on the porous support; and a noble metal element loaded on the porous support. The cerium oxide or the solid solution has an average particle diameter of from 5 to 100 nm. The cerium oxide is present in the solid solution in an amount of from 0.2 to 4.0 by molar ratio with respect to the zirconium oxide therein. The catalyst can be prepared by: coating and calcinating on a support substrate a slurry of a cerium oxide sol, a cerium oxide sol and a zirconium oxide sol, on a solid solution powder of a cerium oxide and a zirconium oxide in a state of mutual solid solution; and loading a noble metal element thereon. The cerium oxide or its solid solution has a surface area large enough to effect an oxygen storage function, and has an average particle diameter large enough to prevent the same from entering deeply into fine pores of a porous support, thereby providing a catalyst fully exhibiting both of the oxygen storage capability and the catalytic activity.

대표청구항 ▼

[ What is claimed is:] [1.] A catalyst for purifying exhaust gases, comprising:a porous support;a cerium oxide loaded on said porous support, and having an average secondary particle diameter of from 5 to 100 nm, said average secondary particle diameter being large enough to prevent most of the ceri

[ What is claimed is:] [1.] A catalyst for purifying exhaust gases, comprising:a porous support;a cerium oxide loaded on said porous support, and having an average secondary particle diameter of from 5 to 100 nm, said average secondary particle diameter being large enough to prevent most of the cerium oxide from entering pores of said porous support, and wherein 50% or more by weight of the particles have an average secondary particle diameter of 100 nm or less; anda noble metal element loaded on said porous support.