The present invention provides an exhaust gas purification catalyst in which platinum group metal migration from a catalyst layer to a base material during high temperature duration is suppressed. The exhaust gas purification catalyst disclosed herein includes a base material, a catalyst layer, and an intermediate layer arranged between the base material and the catalyst layer. The base material contains SiC. The catalyst layer contains a platinum group metal as a catalyst component. The intermediate layer contains substantially no platinum group metal. A product of a thickness of the intermediate layer (μm) and a specific surface area (m.sup.2/g) of the intermediate layer is 1100 or more.

The technology herein disclosed provides a wall flow type exhaust gas purifying catalyst capable of establishing the compatibility between the noxious gas purifying performance and the pressure loss suppressing performance at a high level. The exhaust gas purifying catalyst herein disclosed includes a base material 11 and a catalyst layer 20. Then, a first catalyst region 22 including the catalyst layer 20 formed therein is provided on an entry side surface 16a of a partition wall 16 of the base material 11. A second catalyst region 24 including the catalyst layer 20 formed on a wall surface 18a of a pore 18 is provided in a prescribed region from an exit side surface 16b of the partition wall toward an entry side cell 12. Further, a catalyst unformed region 30 in which a catalyst layer is substantially not formed is provided between the first catalyst region 22 and the second catalyst region 24 in the thickness direction Y of the partition wall 16. As a result of this, it is possible to prevent the deposition of PMs in the second catalyst region 24 including the catalyst layer 20 formed in the pore 18, and to establish the compatibility between the noxious gas purifying performance and the pressure loss suppressing performance at a high level.

Subject of the invention is an exhaust gas purification system for a gasoline engine, comprising in consecutive order the following devices: a first three-way-catalyst (TWC1), a gasoline particulate filter (GPF) and a second three-way-catalyst (TWC2), wherein the oxygen storage capacity (OSC) of the GPF is greater than the OSC of the TWC2, wherein the OSC is determined in mg/l of the volume of the device. The invention also relates to methods in which the system is used and uses of the system.

A three-way catalyst article, and its use in an exhaust system for internal combustion engines, is disclosed. The catalyst article for treating exhaust gas comprising: a substrate comprising an inlet end and an outlet end with an axial length L; a first catalytic region comprising a first platinum group metal (PGM) component and a first oxygen storage capacity (OSC) material, wherein the first OSC material has a fresh specific surface area (SSA) of at least 10 m.sup.2/g; and wherein the first OSC material has an SSA difference of no more than 30 m.sup.2/g between the fresh first OSC material and the aged first OSC material.

A cerium-zirconium oxide-based ionic conductor (CZOIC) material including zirconium oxide in an amount ranging from 5 wt. % up to 95 wt. %, cerium oxide in an amount ranging from 95 wt. % to 5 wt. %, and at least one oxide or a rare earth metal in an amount ranging from 30 wt. % or less, based on the overall mass of the CZOIC material. The CZOIC material exhibits a structure comprising one or more expanded unit cells and a plurality of crystallites having ordered nano-domains. The structure of the CZOIC material exhibits a crystal lattice defined by a d-value measured at multiple (hkl) locations using a SAED technique that exhibit distortions, such that the d-values for the same (hkl) location varies from about 2% to about 5% from the d-value measured for a reference cerium-zirconium material at the same (hkl) location.

An exhaust gas control system according to the present disclosure includes: a first exhaust gas control catalyst layer that controls an exhaust gas emitted from an internal combustion engine; and a second exhaust gas control catalyst layer that further controls the exhaust gas that has been controlled by the first exhaust gas control catalyst layer. The second exhaust gas control catalyst layer contains an oxygen storage material. The ratio of the amount (mmol—CO.sub.2/m.sup.2) of base points per specific surface area (m.sup.2/g) of the oxygen storage material to the specific surface area is equal to or less than 4.50×10.sup.−5.

In an exhaust gas purification catalyst, a catalytic component (100) containing a first oxide (21), a second oxide (22), and a precious metal (30) is supported on a three-dimensional structure (10); the ratio of the amount of precious metal (30) supported on the first oxide (21) to the total amount of precious metal (30) supported on the first oxide (21) and precious metal (30) supported on the second oxide (22), or the ratio of the amount of precious metal (30) supported on the second oxide (22) to the total amount of precious metal (30) supported on the first oxide (21) and precious metal (30) supported on the second oxide (22) is 70% or more to 100% or less, as measured by an electron probe microanalyzer (EPMA); and the amount of carbon monoxide that the precious metal (30) can adsorb per unit mass is 15 mL/g or more to 100 mL/g or less.

A catalytic converter system having oxygen storage materials is disclosed and methods for determining whether to reactivate oxygen storage materials and monitoring failure events of the oxygen storage materials are also disclosed.

In accordance with the technology herein disclosed, an exhaust gas purification catalyst exhibiting a high exhaust gas purifying performance using a new rare earth-containing material is provided. The exhaust gas purification catalyst herein disclosed includes a base material and a catalyst layer formed on the surface of the base material. The catalyst layer of such an exhaust gas purification catalyst includes rare earth-carrying alumina 50 including a primary particle of a rare earth particle 40 including at least one rare earth element carried on the surface of an alumina carrier 30 including alumina, and the average particle diameter D.sub.50 based on TEM observation of the rare earth particle 40 in the rare earth-carrying alumina 50 is 10 nm or less. As a result of this, it is possible to provide an exhaust gas purification catalyst having high NOx adsorption performance and CO adsorption performance

An exhaust gas purification catalyst device including a substrate and an SCR catalyst layer on the substrate, the substrate containing catalyst precious metal particles directly supported on the substrate, the catalyst precious metal particles containing Pt, and the catalyst precious metal particles having an average particle diameter of 30 to 120 nm inclusive.