To reduce an OSC material, while maintaining necessary OSC capacity; and to improve heat resistance and reactivity of a precious metal. Proposed is an exhaust gas purifying catalyst which comprises a first catalyst layer that is formed on the surface of a substrate that is formed of a ceramic or a metal, and a second catalyst layer that is formed on the upper side of the first catalyst layer. The first catalyst layer comprises a precious metal, an OSC material and an alumina, and the OSC material and the alumina are comprised at a mass ratio of OSC material:alumina=1:7 to 1:3. The second catalyst layer comprises a precious metal, an OSC material and an alumina, and the OSC material and the alumina are comprised at a mass ratio of OSC material:alumina=1:1 to 10:0.

The present technology relates to perovskite materials for oxygen storage. In one aspect, the perovskite material includes at least one platinum group metal (PGM) andat least one perovskite compound selected from the group consisting of formula (a): La.sub.xMO.sub.3 and formula (b): La.sub.(1-y)Sr.sub.yMO.sub.3, wherein: M is selected from the group consisting of Co, Cu, Fe, Mn and Ni; x is about 0.7 to about 1.1; and y is 0 to about 0.8, and wherein M, x, and y are independently variable for each one of said perovskite compounds. In one exemplary method, the perovskite materials of the technology are employed to treat automotive exhaust gas. In one embodiment, the perovskite materials are included in the washcoat of an automotive catalytic converter.

A method for removing NO.sub.X from an oxygen-rich exhaust flow produced by a combustion source that is combusting a lean mixture of air and fuel may include passing the oxygen-rich exhaust flow through an exhaust aftertreatment system that includes a NO.sub.X oxidation catalyst that includes perovskite oxide particles, a NO.sub.X storage catalyst, and a NO.sub.X reduction catalyst.

The present disclosure provides an exhaust gas purification material and an exhaust gas purification device that can efficiently remove harmful components even after being exposed to high temperature. Such exhaust gas purification material comprises metal oxide particles and noble metal particles supported on the metal oxide particles. The noble metal particles have a particle size distribution with a mean of 1.5 nm and 18 nm and a standard deviation of less than 1.6 nm.

The exhaust gas-purifying catalyst of the invention includes a noble metal, and crystallites that form CZ composite metal particles which serve as a carrier supporting the noble metal and contain at least zirconium (Zr) and cerium (Ce). The CZ composite oxide particles (crystallites) further contain crystal growth-suppressing fine particles which are fine metal particles comprising primarily a metallic element M that melts at 1,500° C. or above and which suppress crystal growth by the CZ composite oxide particles. The content of the metallic element M included in the CZ composite oxide particles, expressed in terms of the oxide thereof, is 0.5 mol % or less of the total oxide.

Provided is a particulate filter in which a PM collection rate is stably increased. The particulate filter according to the present invention includes a substrate 10 having a wall flow structure having a porous partition wall 16 that partitions an inlet cell and an outlet cell, and a wash coat layer held on surfaces of internal pores of the partition wall. In addition, average filling rates A, B, and C of the wash coat layer measured for each predetermined pore diameter range in the internal pores satisfy specific relationships. Further, the wash coat layer is formed in a region that occupies 50% or more of a thickness of the partition wall, and an amount of a noble metal catalyst carried by the wash coat layer is 0 g/L or more but 0.2 g/L or less.

An oxygen storage material comprises three pyrochlore-type composite oxides which are a ceria-zirconia composite oxide, a lanthana-zirconia composite oxide, and a ceria-zirconia-lanthana composite oxide, and which coexist together, wherein the oxygen storage material contains: first secondary particles made of the pyrochlore-type ceria-zirconia composite oxide and the pyrochlore-type ceria-zirconia-lanthana composite oxide; and second secondary particles made of the pyrochlore-type lanthana-zirconia composite oxide and the pyrochlore-type ceria-zirconia-lanthana composite oxide.

Described is a selective catalytic reduction material comprising a spherical particle including an agglomeration of crystals of a molecular sieve. The catalyst is a crystalline material that is effective to catalyze the selective catalytic reduction of nitrogen oxides in the presence of a reductant at temperatures between 200° C. and 600° C. A method for selectively reducing nitrogen oxides and an exhaust gas treatment system are also described.

A catalyst system for reducing N.sub.2O emissions in the exhaust system of a vehicle is provided and comprises a support in communication with the exhaust gas stream, with the support including an exhaust gas inlet and an exhaust gas outlet. The support has at least one exhaust gas passage therethrough. The support, which may be in the form of a monolithic, multi-cell honeycomb construction, comprises a first catalytic zone and a second catalytic zone positioned downstream from the first zone. The first catalytic zone includes rhodium or a rhodium-enriched catalyst, while the second catalytic zone includes palladium or a palladium-enriched catalyst.

[Problem] Provided is an exhaust gas purification catalyst capable of exhibiting even higher exhaust gas purification performance without impairing Pd catalytic activity, and an exhaust gas purification system using the exhaust gas purification catalyst.

[Solution] Provided is an exhaust gas purification catalyst comprising a substrate and a catalyst layer provided on the substrate, said catalyst having a first section located upstream along a flow direction of the exhaust gas and a second section located downstream from the first section; the catalyst layer in the first section comprises a first catalyst layer comprising palladium and a second catalyst layer comprising rhodium and covering the first catalyst layer, wherein a pore volume proportion is 12% or more and less than 18% wherein the pore volume proportion is a proportion of a total volume of the pores, which have a pore diameter of 0.06 μm to 30.0 μm as measured by mercury press-in method and existing in the substrate and the catalyst layer in the first section to a volume of a entire first section; and a wash coat amount is 100 g/L to 190 g/L, wherein a wash coat amount is a mass per unit volume of the catalyst layer in the first section to the volume of the substrate existing in the first section.