Exhaust gas purification catalyst

摘要

An exhaust gas purification catalyst includes a catalytic layer on a carrier, in which a particle component A and a particle component B are mixed. The particle component A is composed of catalytic-metal-doped CeZr-based mixed oxide powder, and has a particle size distribution with a peak in a particle size range of equal to or greater than 100 nm and equal to or less than 300 nm. A CeO2/(CeO2+ZrO2) mass ratio of CeZr-based mixed oxide is equal to or greater than 30% and equal to or less than 75%. The particle component B is composed of at least one selected from a group consisting of activated alumina powder, Zr-based-oxide-supported alumina powder, and catalytic-metal-undoped CeZr-based mixed oxide powder. At least a part of particles of the particle component B has a particle size larger than that of the particle component A.

主权项

1. An exhaust gas purification catalyst, comprising:
a catalytic layer containing a particle component A and a particle component B on a carrier, wherein the particle component A is composed of catalytic-metal-doped CeZr-based mixed oxide powder in which catalytic metal is solid-dissolved in CeZr-based mixed oxide, the particle component B is composed of activated alumina powder, which has a number-average particle size of equal to or greater than 5 μm and equal to or less than 30 μm, Zr—La mixed oxide-supported alumina powder in which Zr—La mixed oxide is supported on activated alumina particles, which has a number-average particle size of equal to or greater than 10 μm and equal to or less than 50 μm, and CeZr-based mixed oxide powder in which catalytic metal is not solid-dissolved, which has a number-average particle size of equal to or greater than 0.5 μm and equal to or less than 5.0 μm, the particle component A has a particle size distribution with a peak in a particle size range of equal to or greater than 100 nm and equal to or less than 300 nm, and has a CeO2 amount of equal to or greater than 30% by mass and equal to or less than 75% by mass in a total amount of CeO2 and ZrO2, and the particle components A and B are mixed such that the particle component A is at least partially interposed between particles of the particle component B in the catalytic layer.