초록 ▼

The invention relates to a first catalyst for purifying an exhaust gas. The first catalyst has a substrate and a catalytic coating formed thereon. This catalytic coating has first and second grains. The first grain includes a porous carrier supporting thereon at least one of palladium and rhodium. T

The invention relates to a first catalyst for purifying an exhaust gas. The first catalyst has a substrate and a catalytic coating formed thereon. This catalytic coating has first and second grains. The first grain includes a porous carrier supporting thereon at least one of palladium and rhodium. The second grain includes a double oxide supporting thereon at least one of platinum and palladium. This double oxide is represented by a formula of (La.sub.1-x A.sub.x).sub.1-.alpha. BO.sub..delta. where A is at least one element selected from barium, potassium and cesium, B is at least one of iron, cobalt, nickel and manganese, 0

대표청구항 ▼

[ What is claimed is:] [1.] A catalyst for purifying an exhaust gas, said catalyst comprising:a substrate; anda catalytic coating formed on said substrate, said catalytic coating comprising:a first grain including a porous carrier which supports thereon at least one first noble metal selected from t

[ What is claimed is:] [1.] A catalyst for purifying an exhaust gas, said catalyst comprising:a substrate; anda catalytic coating formed on said substrate, said catalytic coating comprising:a first grain including a porous carrier which supports thereon at least one first noble metal selected from the group consisting of palladium and rhodium; anda second grain including a first double oxide which supports thereon at least one second noble metal selected from the group consisting of platinum and palladium, said first double oxide being represented by the following general formula (1); EQU (La.sub.1-x A.sub.x).sub.1-.alpha. BO.sub..delta. ( 1) re A is at least one element selected from the group consisting of barium, potassium and cesium, B is at least one transition element selected from the group consisting of iron, cobalt, nickel and manganese, x is a number which is greater than 0 and less than 1, .alpha. is a number which is greater than 0 and less than 0.2, and .delta. is a number which is greater than zero, wherein said first double oxide further comprises zirconium.