Abstract: The exhaust gas purification device includes: a substrate including an upstream and a downstream ends; a first catalyst layer extending across a first region and containing a first rhodium-containing catalyst and a first cerium-containing oxide, the first rhodium-containing catalyst containing a first metal oxide carrier and first rhodium particles supported on the first metal oxide carrier, a mean of a particle size distribution of the first rhodium particles being 1.5 nm to 18 nm; and a second catalyst layer extending across a second region and containing a second rhodium-containing catalyst containing a second metal oxide carrier and second rhodium particles supported on the second metal oxide carrier, a cerium content in the first catalyst layer based on a volume capacity of the substrate in the first region being higher than a cerium content in the second catalyst layer based on a volume capacity of the substrate in the second region.

Abstract: Provided are a method for producing an exhaust gas purification material and a method for manufacturing an exhaust gas purification device that allow efficient removal of a harmful component even after exposure to a high temperature environment. The method for producing the exhaust gas purification material includes the steps, in this order, of: (a) impregnating a metal oxide carrier with a rhodium compound solution; (b) drying the metal oxide carrier impregnated with the rhodium compound solution to obtain a rhodium-containing catalyst containing the metal oxide carrier and rhodium particles supported on the metal oxide carrier; (c) heating the rhodium-containing catalyst at a temperature within a range from 700° C. to 900° C. under an inert atmosphere; and (d) mixing the rhodium-containing catalyst with a material having a basicity higher than a basicity of the metal oxide carrier.

Abstract: The exhaust gas purification device includes: a substrate including an upstream end through which an exhaust gas is introduced and a downstream end through which the exhaust gas is discharged; a first catalyst layer containing a rhodium-containing catalyst containing a metal oxide carrier and rhodium particles supported on the metal oxide carrier, the first catalyst layer extending across a first region; and a second catalyst layer containing palladium particles and a material having a basicity higher than a basicity of the metal oxide carrier, the second catalyst layer extending across a second region. A mean of a particle size distribution of the rhodium particles is from 1.5 nm to 18 nm.

Abstract: An exhaust gas purification catalyst including an alkaline-earth metal carried on a porous carrier in a highly dispersed state. The catalyst layer of the exhaust gas purification catalyst has an alkaline-earth metal carrying region including a porous carrier, Pt, and a sulfuric acid salt of at least one alkaline-earth metal carried on the porous carrier, wherein a value of RAe/Pt is 0.5 or more, where RAe/Pt represents the Pearson's correlation coefficient calculated using ? and ? in each pixel obtained by, for a cross section of the region, performing the area analysis by FE-EPMA under the conditions of: pixel size 0.34 ?m×0.34 ?m; and number of measured pixels 256×256; and measuring an intensity (?: cps) of a characteristic X ray of an element (Ae) of the alkaline-earth metal and an intensity (?: cps) of a characteristic X ray of Pt for each pixel.

Abstract: The present disclosure provides an exhaust gas purification catalyst having improved durability, which comprises a substrate and a catalyst coat layer formed on the substrate, the catalyst coat layer having a two-layer structure, wherein the catalyst coat layer includes an upstream portion on an upstream side and a downstream portion on a downstream side in an exhaust gas flow direction, and a part or all of the upstream portion is formed on a part of the downstream portion, wherein the downstream portion contains Rh fine particles, and wherein the Rh fine particles have an average particle size measured by a transmission electron microscope observation of 1.0 nm or more to 2.0 nm or less, and a standard deviation ? of the particle size of 0.8 nm or less.

Abstract: The present disclosure provides an exhaust gas purification catalyst having an improved Rh activation, which comprises a substrate and a catalyst coat layer formed on the substrate, the catalyst coat layer having a two-layer structure, wherein the catalyst coat layer includes an upstream portion on an upstream side and a downstream portion on a downstream side in an exhaust gas flow direction, and a part or all of the upstream portion is formed on a part of the downstream portion, wherein the upstream portion contains Rh fine particles and Pt, wherein the Rh fine particles have an average particle size measured by a transmission electron microscope observation of 1.0 nm or more to 2.0 nm or less, and a standard deviation ? of the particle size of 0.8 nm or less, and wherein the downstream portion contains Rh.

Abstract: An exhaust gas purification catalyst including particles of a catalyst metal supported on secondary particles of an inorganic oxide, wherein when scanning transmission electron microscope-energy dispersive X-ray line analysis is performed from a surface of the secondary particles toward a center thereof, a support density of the catalyst metal on a surface side of the secondary particles is greater than the support density of the catalyst metal in a center part of the secondary particles.

Abstract: The present disclosure relates to an exhaust gas control catalyst including a base and a catalyst coating layer having a two-layer structure on the base. The catalyst coating layer includes a lower layer on the base, and an upper layer on the lower layer. The upper layer of the catalyst coating layer contains Rh particles in which a mean particle diameter measured by observation using a transmission electron microscope is 1.0 nm or more and 2.0 nm or less and a particle-diameter standard deviation ? is 0.8 nm or less. A length of the upper layer from an end face on a downstream side in an exhaust gas flow direction falls within a range of 70% or more and 100% or less of a total length of the base.

Abstract: The present disclosure provides an exhaust gas purification catalyst having an improved low-temperature activity, which comprises a substrate and a catalyst coat layer formed on the substrate, wherein the catalyst coat layer contains Rh fine particles and a promoter comprising a Ce—Zr-based composite oxide and a Zr-based composite oxide not containing cerium oxide, wherein the Rh fine particles have an average particle size measured by a transmission electron microscope observation of 1.0 nm or more to 2.0 nm or less, and a standard deviation ? of the particle size of 0.8 nm or less, and wherein the Rh fine particles are supported on each of the Ce—Zr-based composite oxide and the Zr-based composite oxide not containing cerium oxide.

Abstract: A supported catalyst particles include oxide carrier particles and noble metal particles supported on the oxide carrier particles, wherein the mass of the noble metal particles is less than or equal to 5 mass % based on the mass of the oxide carrier particles, and the average particle size of the noble metal particles measured by transmission electron microscopy is 1.0-2.0 nm, with the standard deviation ? less than or equal to 0.8 nm.

Abstract: An exhaust gas purification catalyst including an alkaline-earth metal carried on a porous carrier in a highly dispersed state. The catalyst layer of the exhaust gas purification catalyst has an alkaline-earth metal carrying region including a porous carrier, Pt, and a sulfuric acid salt of at least one alkaline-earth metal carried on the porous carrier, wherein a value of RAe/Pt is 0.5 or more, where RAe/Pt represents the Pearson's correlation coefficient calculated using ? and ? in each pixel obtained by, for a cross section of the region, performing the area analysis by FE-EPMA under the conditions of: pixel size 0.34 ?m×0.34 ?m; and number of measured pixels 256×256; and measuring an intensity (?: cps) of a characteristic X ray of an element (Ae) of the alkaline-earth metal and an intensity (?: cps) of a characteristic X ray of Pt for each pixel.

Abstract: The present disclosure provides an exhaust gas purification catalyst having an improved Rh activation, which comprises a substrate and a catalyst coat layer formed on the substrate, the catalyst coat layer having a two-layer structure, wherein the catalyst coat layer includes an upstream portion on an upstream side and a downstream portion on a downstream side in an exhaust gas flow direction, and a part or all of the upstream portion is formed on a part of the downstream portion, wherein the upstream portion contains Rh fine particles and Pt, wherein the Rh fine particles have an average particle size measured by a transmission electron microscope observation of 1.0 nm or more to 2.0 nm or less, and a standard deviation ? of the particle size of 0.8 nm or less, and wherein the downstream portion contains Rh.

Abstract: The present disclosure relates to an exhaust gas control catalyst including a base and a catalyst coating layer having a two-layer structure on the base. The catalyst coating layer includes a lower layer on the base, and an upper layer on the lower layer. The upper layer of the catalyst coating layer contains Rh particles in which a mean particle diameter measured by observation using a transmission electron microscope is 1.0 nm or more and 2.0 nm or less and a particle-diameter standard deviation ? is 0.8 nm or less. A length of the upper layer from an end face on a downstream side in an exhaust gas flow direction falls within a range of 70% or more and 100% or less of a total length of the base.

Abstract: The present disclosure provides an exhaust gas purification catalyst having improved durability, which comprises a substrate and a catalyst coat layer formed on the substrate, the catalyst coat layer having a two-layer structure, wherein the catalyst coat layer includes an upstream portion on an upstream side and a downstream portion on a downstream side in an exhaust gas flow direction, and a part or all of the upstream portion is formed on a part of the downstream portion, wherein the downstream portion contains Rh fine particles, and wherein the Rh fine particles have an average particle size measured by a transmission electron microscope observation of 1.0 nm or more to 2.0 nm or less, and a standard deviation a of the particle size of 0.8 nm or less.

Abstract: The present disclosure provides an exhaust gas purification catalyst having an improved low-temperature activity, which comprises a substrate and a catalyst coat layer formed on the substrate, wherein the catalyst coat layer contains Rh fine particles and a promoter comprising a Ce—Zr-based composite oxide and a Zr-based composite oxide not containing cerium oxide, wherein the Rh fine particles have an average particle size measured by a transmission electron microscope observation of 1.0 nm or more to 2.0 nm or less, and a standard deviation a of the particle size of 0.8 nm or less, and wherein the Rh fine particles are supported on each of the Ce—Zr-based composite oxide and the Zr-based composite oxide not containing cerium oxide.

Abstract: An exhaust gas purification catalyst including particles of a catalyst metal supported on secondary particles of an inorganic oxide, wherein when scanning transmission electron microscope-energy dispersive X-ray line analysis is performed from a surface of the secondary particles toward a center thereof, a support density of the catalyst metal on a surface side of the secondary particles is greater than the support density of the catalyst metal in a center part of the secondary particles.

Abstract: An exhaust gas cleaning catalyst for inhibiting particulates grain growth includes composite metal particulates containing Pd and Rh, where the average proportion of the total Rh atoms relative to the total Pd and Rh atoms is 0.5 atom %, and given an X-ray wavelength of 1.5403 ?, when the diffraction surface in XRD analysis is the crystal lattice face of the Pd(111), and diffraction angles 2? indicating the diffraction peak positions on the diffraction surface are identified, the absolute value of the difference between the theoretical lattice constant B from a formula related to Vegard's law using the identified values, and the actual lattice constant C from a formula related to lattice constants and Bragg's law does not exceed 1.020×10?3 (?). A smaller absolute value of the difference between the theoretical and actual lattice constants is associated with a higher degree to which the Pd and Rh are combined with one another.