Abstract: The present invention provides an exhaust gas purification catalyst including an alkaline earth metal supported in a highly dispersed state on a porous carrier. A catalyst layer of the exhaust gas purification catalyst provided by the invention has an alkaline earth metal-supporting region including a porous carrier, a catalyst metal belonging to the platinum group, and a sulfate of at least one type of alkali earth metal supported on the porous carrier. In a cross-section of this region, a Pearson correlation coefficient RAe/M is at least 0.5 as calculated using ? and ? for each pixel obtained by carrying out area analysis by FE-EPMA under conditions of pixel size of 0.34 ?m×0.34 ?m, and measured pixel number 256×256, and by measuring the characteristic X-ray intensity (?: cps) of the alkaline earth metal element (Ae) and the characteristic X-ray intensity (?: cps) of the main constituent element of the inorganic compound constituting the porous carrier for each pixel.

Abstract: An object of the present invention is to provide an exhaust gas purification catalyst which can exhibit high durability and warm-up performance. The present invention relates to an exhaust gas purification catalyst comprising a substrate and a catalyst coating layer formed on the substrate, wherein the catalyst coating layer comprises catalyst particles, the catalyst coating layer having an upstream region extending by 40 to 60% of the entire length of the substrate from an upstream end of the catalyst in the direction of an exhaust gas flow and a downstream region corresponding to the remainder portion of the catalyst coating layer, the composition of the catalyst particle of the upstream region being different from that of the downstream region. The upstream region in the direction of an exhaust gas flow has a structure where a void is included in a large number, and furthermore high-aspect-ratio pores having an aspect ratio of 5 or more account for a certain percentage or more of the whole volume of voids.

Abstract: An object of the present invention is to provide an exhaust gas purification catalyst which can exhibit high durability and warm-up performance. The present invention relates to an exhaust gas purification catalyst comprising a substrate and a catalyst coating layer formed on the substrate, wherein the catalyst coating layer comprises catalyst particles, the catalyst coating layer having an upstream region extending by 40 to 60% of the entire length of the substrate from an upstream end of the catalyst in the direction of an exhaust gas flow and a downstream region corresponding to the remainder portion of the catalyst coating layer, the composition of the catalyst particle of the upstream region being different from that of the downstream region. The upstream region in the direction of an exhaust gas flow has a structure where a void is included in a large number, and furthermore high-aspect-ratio pores having an aspect ratio of 5 or more account for a certain percentage or more of the whole volume of voids.

Abstract: When the amount of coating is increased in a two-layer catalyst or the like containing two noble metals in respective different layers, gas diffusivity in the catalyst and use efficiency of a catalytic active site are reduced to thereby reduce purification performance. In view of this, an organic fiber having a predetermined shape is used as a pore-forming material in formation of an uppermost catalyst coating layer of a multi-layer catalyst, to thereby form an uppermost catalyst coating layer having a high-aspect-ratio pore excellent in connectivity and therefore excellent gas diffusivity.

Abstract: The object of the present invention is to provide an exhaust gas purifying catalyst that can achieve high purification performance while suppressing H2S emissions. The object is solved by an exhaust gas purifying catalyst in which the lower layer of the catalyst coating layer comprises a ceria-zirconia composite oxide having a pyrochlore-type ordered array structure, in which the ceria-zirconia composite oxide contains at least one additional element selected from the group consisting of praseodymium, lanthanum, and yttrium at 0.5 to 5.0 mol % in relation to the total cation amount, and the molar ratio of (cerium+additional element):(zirconium) is within the range from 43:57 to 48:52.

Abstract: An object of the present disclosure is to provide an exhaust gas purification catalyst device; an exhaust gas purification system; and a method for detecting deterioration of the above device. The exhaust gas purification catalyst device includes a substrate, a first catalyst layer containing Pd and formed on the substrate, and a second catalyst layer formed on the first layer. Regarding the above device, ceria, Pd, and Rh are contained in a mixed state in the second layer; in the first and second layers, the total mass of ceria having a fluorite-type structure per 1 L volume of the substrate is 16.0 g or less; and in the second layer, the mass of Pd per 1 L volume of the substrate is 0.32 g or more.

Abstract: The object of the present invention is to provide an exhaust gas purifying catalyst that can achieve high purification performance while suppressing H2S emissions. The object is solved by an exhaust gas purifying catalyst in which the top layer of a catalyst coating layer comprises a ceria-zirconia composite oxide having a pyrochlore-type ordered array structure, in which the ceria-zirconia composite oxide contains at least one additional element selected from the group consisting of praseodymium, lanthanum, and yttrium at 0.5 to 5.0 mol % in relation to the total cation amount, and the molar ratio of (cerium+additional element):(zirconium) is within the range from 43:57 to 48:52.

Abstract: The present invention is directed to address the following problem: in an exhaust gas purification catalyst comprising a dual catalyst of a combination of a startup catalyst and an underfloor catalyst, reduction in the gas diffusivity of the underfloor catalyst results in reduction in the use efficiency of a catalytic active site, resulting in reduction in purification performance. The present invention relates to an exhaust gas purification catalyst comprising a dual catalyst of a combination of a startup catalyst and an underfloor catalyst having a catalyst coating where a large number of voids are included, wherein high-aspect-ratio pores having an aspect ratio of 5 or more account for a certain rate or more of the whole volume of the voids, to thereby enhance the purification performance of the catalyst.

Abstract: The object of the present invention is to provide a high-performance exhaust gas purifying catalyst that can achieve oxygen absorption/release capacity and NOx purification performance. The object is solved by an exhaust gas purifying catalyst, which comprises a ceria-zirconia composite oxide having a pyrochlore-type ordered array structure in the upstream part of the catalyst coating layer, in which the ceria-zirconia composite oxide contains at least one additional element selected from the group consisting of praseodymium, lanthanum, and yttrium at 0.5 to 5.0 mol % of the total cation amount, and has a molar ratio of (cerium+the additional element):(zirconium) of 43:57 to 48:52.

Abstract: A catalyst for purification of exhaust gas, wherein a substrate and a catalyst coat layer which is formed on a surface of the substrate and which comprises catalyst particles, wherein the catalyst coat layer has an average thickness in a range of 25 to 160 ?m, and a void fraction in a range of 50 to 80% by volume as measured by a weight-in-water method, 0.5 to 50% by volume of all voids in the catalyst coat layer consist of high-aspect ratio pores which have equivalent circle diameters in a range of 2 to 50 ?m in a cross-sectional image of a cross-section of the catalyst coat layer which the cross-section is perpendicular to a flow direction of exhaust gas in the substrate, and which have aspect ratios of 5 or higher, and the high-aspect ratio pores have an average aspect ratio in a range of 10 to 50.

Abstract: The object of the present invention is to provide a high-performance exhaust gas purifying catalyst that can achieve oxygen absorption/release capacity and NOx purification performance. The object is solved by an exhaust gas purifying catalyst, which comprises a ceria-zirconia composite oxide having a pyrochlore-type ordered array structure in the upstream part of the catalyst coating layer, in which the ceria-zirconia composite oxide contains at least one additional element selected from the group consisting of praseodymium, lanthanum, and yttrium at 0.5 to 5.0 mol % of the total cation amount, and has a molar ratio of (cerium+the additional element):(zirconium) of 43:57 to 48:52.

Abstract: An object of the present invention is to provide an exhaust gas purification catalyst which can exhibit high durability and warm-up performance. The present invention relates to an exhaust gas purification catalyst comprising a substrate and a catalyst coating layer formed on the substrate, wherein the catalyst coating layer comprises catalyst particles, the catalyst coating layer having an upstream region extending by 40 to 60% of the entire length of the substrate from an upstream end of the catalyst in the direction of an exhaust gas flow and a downstream region corresponding to the remainder portion of the catalyst coating layer, the composition of the catalyst particle of the upstream region being different from that of the downstream region. The upstream region in the direction of an exhaust gas flow has a structure where a void is included in a large number, and furthermore high-aspect-ratio pores having an aspect ratio of 5 or more account for a certain percentage or more of the whole volume of voids.

Abstract: A catalyst for purification of exhaust gas, wherein a substrate and a catalyst coat layer which is formed on a surface of the substrate and which comprises catalyst particles, wherein the catalyst coat layer has an average thickness in a range of 25 to 160 ?m, and a void fraction in a range of 50 to 80% by volume as measured by a weight-in-water method, 0.5 to 50% by volume of all voids in the catalyst coat layer consist of high-aspect ratio pores which have equivalent circle diameters in a range of 2 to 50 ?m in a cross-sectional image of a cross-section of the catalyst coat layer which the cross-section is perpendicular to a flow direction of exhaust gas in the substrate, and which have aspect ratios of 5 or higher, and the high-aspect ratio pores have an average aspect ratio in a range of 10 to 50.

Abstract: An object of the present invention is to provide an exhaust gas purification catalyst which can exhibit sufficient purification performance even under a high Ga condition. The present invention relates to an exhaust gas purification catalyst comprising a substrate and a catalyst coating layer formed on the substrate, wherein the catalyst coating layer comprises catalyst particles, the catalyst coating layer having an upstream region extending by 40 to 60% of the entire length of the substrate from an upstream end of the catalyst in the direction of an exhaust gas flow and a downstream region corresponding to the remainder portion of the catalyst coating layer, the composition of the catalyst particle of the upstream region being different from that of the downstream region.

Abstract: The object of the present invention is to provide an exhaust gas purifying catalyst that can achieve high purification performance while suppressing H2S emissions. The object is solved by an exhaust gas purifying catalyst in which the lower layer of the catalyst coating layer comprises a ceria-zirconia composite oxide having a pyrochlore-type ordered array structure, in which the ceria-zirconia composite oxide contains at least one additional element selected from the group consisting of praseodymium, lanthanum, and yttrium at 0.5 to 5.0 mol % in relation to the total cation amount, and the molar ratio of (cerium+additional element):(zirconium) is within the range from 43:57 to 48:52.

Abstract: A catalyst for exhaust gas purification is described which includes a substrate and a catalyst coating layer provided on the substrate. The catalyst coating layer includes first and second metal oxide particles. The first metal oxide particles have a catalyst metal supported thereon, and the second metal oxide particles do not have a catalyst metal supported thereon. The first and second metal oxide particles have a specific particle size. This is because, when the sizes of the particles supporting the catalyst metal remain relatively large but the sizes of the particles not supporting a catalyst metal are minimized, it is possible to decrease the thickness of the catalyst coating layer while maintaining durability and improving gas diffusibility of the coating layer. Therefore, a thickness of the catalyst coating is decreased without decreasing durability, and the catalyst can exhibit high exhaust gas purification performance even under high load conditions.

Abstract: When the amount of coating is increased in a two-layer catalyst or the like containing two noble metals in respective different layers, gas diffusivity in the catalyst and use efficiency of a catalytic active site are reduced to thereby reduce purification performance. In view of this, an organic fiber having a predetermined shape is used as a pore-forming material in formation of an uppermost catalyst coating layer of a multi-layer catalyst, to thereby form an uppermost catalyst coating layer having a high-aspect-ratio pore excellent in connectivity and therefore excellent gas diffusivity.

Abstract: The problem of the present invention is to provide an exhaust gas purification catalyst which can exhibit sufficient purification performance under a high Ga condition while having a resistance to stress such as high-temperature and poisonous substances. The present invention relates to an exhaust gas purification catalyst comprising two or more catalyst coating layers on a substrate, wherein a lower catalyst coating layer that is present lower with respect to an uppermost catalyst coating layer has a structure where a large number of voids are included and high-aspect-ratio pores having an aspect ratio of 5 or more account for a certain proportion or more of the whole volume of voids, thereby to improve gas diffusivity in the lower catalyst coating layer.

Abstract: The present invention is directed to address the following problem: in an exhaust gas purification catalyst comprising a dual catalyst of a combination of a startup catalyst and an underfloor catalyst, reduction in the gas diffusivity of the underfloor catalyst results in reduction in the use efficiency of a catalytic active site, resulting in reduction in purification performance. The present invention relates to an exhaust gas purification catalyst comprising a dual catalyst of a combination of a startup catalyst and an underfloor catalyst having a catalyst coating where a large number of voids are included, wherein high-aspect-ratio pores having an aspect ratio of 5 or more account for a certain rate or more of the whole volume of the voids, to thereby enhance the purification performance of the catalyst.

Abstract: The present invention is directed to address the following problem: in an exhaust gas purification catalyst comprising a dual catalyst of a combination of a startup catalyst and an underfloor catalyst, reduction in the gas diffusivity of the startup catalyst results in reduction in the use efficiency of a catalytic active site, resulting in reduction in purification performance. The present invention relates to an exhaust gas purification catalyst comprising a dual catalyst of a combination of a startup catalyst having a catalyst coating where a large number of voids are included and an underfloor catalyst, wherein high-aspect-ratio pores having an aspect ratio of 5 or more account for a certain rate or more of the whole volume of the voids, to thereby enhance the purification performance of the catalyst.