Abstract: An exhaust gas purification catalyst has a substrate, a lower catalyst layer that is formed on the substrate and contains at least one of Pd and Pt, and an upper catalyst layer that is formed on the lower catalyst layer and contains Rh. A region that does not contain the upper catalyst layer is disposed on the exhaust gas upstream side of this exhaust gas purification catalyst. The lower catalyst layer includes a front-stage lower catalyst layer on the exhaust gas upstream side and a rear-stage lower catalyst layer on the exhaust gas downstream side. The front-stage lower catalyst layer contains an oxygen storage material.

Abstract: An exhaust purifying catalyst includes: a substrate; a first-stage catalyst that includes an oxygen storage capacity (OSC) material and that is provided on the substrate on an upstream side thereof in an exhaust gas flow direction; and a second-stage catalyst that includes an OSC material and that is provided on the substrate on a downstream side thereof in an exhaust gas flow direction. The OSC material included in the first-stage catalyst and the second-stage catalyst includes OSC material on which a noble metal is not supported. The proportion of the amount of the OSC material, on which a noble metal is not supported, and that is included in the second-stage catalyst with respect to the combined amount of the OSC material, on which a noble metal is not supported, and that is included in the first-stage catalyst and the second-stage catalyst is in a range of from 0 to 50 wt %.

Abstract: An exhaust gas control apparatus for an internal combustion engine includes a NOx purification catalyst disposed in an exhaust passage of the internal combustion engine and carrying a first catalyst metal on a first catalyst carrier, an oxidation catalyst disposed in the downstream exhaust passage of the NOx purification catalyst and carrying second catalyst metals including a base metal on a second catalyst carrier, an air introduction apparatus introducing air into an upstream of the oxidation catalyst, and a temperature detector detecting a temperature of the oxidation catalyst. When an oxidation catalyst temperature is a predetermined temperature or lower, an air-fuel ratio of the exhaust gas into the oxidation catalyst is controlled to a more fuel lean ratio than the stoichiometric air-fuel ratio. When the oxidation catalyst temperature exceeds the predetermined temperature, the air-fuel ratio of the exhaust gas into the oxidation catalyst is controlled to the stoichiometric air-fuel ratio.

Abstract: Provided is an exhaust purification system for an internal combustion engine.

Abstract: An exhaust gas purifying catalyst that contains a first oxygen storage material on which no noble metal is supported and which has a pyrochlore phase type regular array structure, and a second oxygen storage material which has a higher oxygen storage rate and a lower oxygen storage capacity than the first oxygen storage material and on which a platinum group noble metal is supported.

Abstract: Provided is an exhaust gas purification catalyst (10) that has a substrate (11), a lower catalyst layer (12) that is formed on the substrate and contains at least one of Pd and Pt, and an upper catalyst layer (13) that is formed on the lower catalyst layer and contains Rh. A region that does not contain the upper catalyst layer is disposed on the exhaust gas upstream side of this exhaust gas purification catalyst, and the lower catalyst layer is formed of a front-stage lower catalyst layer (12a) on the exhaust gas upstream side and a rear-stage lower catalyst layer (12b) on the exhaust gas downstream side. The Front-stage lower, catalyst layer contains an oxygen storage material.

Abstract: An exhaust purifying catalyst includes: a substrate; a first-stage catalyst that includes an oxygen storage capacity (OSC) material and that is provided on the substrate on an upstream side thereof in an exhaust gas flow direction; and a second-stage catalyst that includes an OSC material and that is provided on the substrate on a downstream side thereof in an exhaust gas flow direction. The OSC material included in the first-stage catalyst and the second-stage catalyst includes OSC material on which a noble metal is not supported. The proportion of the amount of the OSC material, on which a noble metal is not supported, and that is included in the second-stage catalyst with respect to the combined amount of the OSC material, on which a noble metal is not supported, and that is included in the first-stage catalyst and the second-stage catalyst is in a range of from 0 to 50 wt %.

Abstract: A ceria-zirconia base composite oxide contains a composite oxide of ceria and zirconia. In the ceria-zirconia base composite oxide, a content ratio between cerium and zirconium in the composite oxide is in a range from 43:57 to 48:52 in terms of molar ratio ([cerium]: [zirconium]). An intensity ratio of a diffraction line at 2?=14.5° to a diffraction line at 2?=29° {I(14/29) value} and an intensity ratio of a diffraction line at 2?=28.5° to the diffraction line at 2?=29° {I(28/29) value}, which are calculated from an X-ray diffraction pattern obtained by an X-ray diffraction measurement using CuKa after heating under a temperature condition of 1100° C. in air for 5 hours, respectively satisfy the following conditions: I(14/29)value?0.015, and I(28/29)value?0.08.

Abstract: An exhaust gas purifying catalyst that contains a first oxygen storage material on which no noble metal is supported and which has a pyrochlore phase type regular array structure, and a second oxygen storage material which has a higher oxygen storage rate and a lower oxygen storage capacity than the first oxygen storage material and on which a platinum group noble metal is supported.

Abstract: A catalytic support 10 is made of rare-earth-element-oxide fine particles (e.g., ceria fine particles 11) comprising primary particles of a rare-earth element oxide, alumina fine particles 12 comprising primary particles of alumna, and barium-compound fine particles 13 comprising primary particles of a barium compound, rare-earth-element-oxide fine particles, alumina fine particles 12 and barium-compound fine particles 13 which are mixed with each other. A primary particle diameter of the rare-earth-element-oxide fine particles is 5 nm or less, and a primary particle diameter of the barium-compound fine particles 13 is 10 nm or less. Platinum fine particles 20 are supported, of this catalytic support 10, on the rare-earth-element-oxide fine particles virtually. It is possible to suppress the granular growth of platinum, which serves an oxidizing catalyst, and the granular growth of barium, which serves an NOx storage material, more securely.