The present disclosure is directed to compositions comprising Ce-containing mixed oxides, especially those having a stoichiometry of Ln.sub.yCe.sub.xM.sub.wO.sub.z; where 0.15≤x≤0.5, y≤0.25, w=(1−x−y)≥0.5, and z=(2x+2w+1.5y); M is Zr, Hf, Ti, Sn or Ge or a combination thereof; Ln is Y and/or one or more rare earth metals, exclusive of Ce,
and the uses of these compositions. These compositions are characterized by the even distribution of the Ce in the lattice of the mixed oxide.

Provided are an exhaust gas purifying catalyst structure that inhibits foil elongation and improves structural durability and a production method therefor. The exhaust gas purifying catalyst structure has a metal support configured by using an mantle and a metal foil provided in the mantle and forming an exhaust gas flow path, and a catalyst layer provided on a surface forming the flow path of the metal foil, wherein the catalyst layer contains a noble metal, an OSC material containing cerium and a rare earth element other than cerium (non-Ce rare earth element), and alumina, and a content of the non-Ce rare earth element with respect to 100% by mass of the catalyst layer is 2.52% by mass or more and 4.62% by mass or less in terms of an oxide.

The catalyst deterioration detection system 1 comprises an air-fuel ratio detection device 41 detecting an air-fuel ratio of an exhaust gas flowing out from the catalyst 20, an air-fuel ratio control part 71, and a deterioration judgment part 72. The air-fuel ratio control part is configured to perform a lean control making the air-fuel ratio of the inflowing exhaust gas leaner than a stoichiometric air-fuel ratio and a rich control making the air-fuel ratio of the inflowing exhaust gas richer than the stoichiometric air-fuel ratio. The deterioration judgment part is configured to calculate an amplitude of an air-fuel ratio of an exhaust gas flowing out from the catalyst due to the lean control and the rich control based on an output of the air-fuel ratio detection device and judge that the catalyst is deteriorating if the amplitude is equal to or greater than a threshold value.

A vehicular exhaust filter comprising a porous substrate having an inlet face and an outlet face with the porous substrate comprising inlet channels extending from the inlet face and outlet channels extending from the outlet face is disclosed. The inlet channels and the outlet channels are separated by a plurality of filter walls having a porous structure. The vehicular exhaust filter is loaded with a refractory powder having a tapped density before loading of less than 0.10 g/cm.sup.3 and the vehicular exhaust filter has a mass loading of the refractory powder of less than 10 g/l.

An electrically heated support according to the present invention includes: a pillar shaped honeycomb structure, the honeycomb structure including an outer peripheral wall and a partition wall, the partition wall defining a plurality of cells, each of the cells penetrating from one end face to other end face to form a flow path; and a pair of electrode terminals provided on a surface of the outer peripheral wall. In a cross section of the honeycomb structure, the honeycomb structure includes: a plurality of first slits arranged, the first slits being configured to define an energizing path; and a least one second slit located in the energizing path, the second slit extending in a different direction from that of the first slits. A length of the energizing path from one electrode terminal to the other electrode terminal is longer than a diameter of the honeycomb structure.

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.

Passive NO.sub.x adsorption (PNA) compositions have a formula Pd—NiFe.sub.2O.sub.4 wherein Pd represents a palladium component, such as palladium oxide, that is adsorbed on surfaces of the nickel ferrite. Such compositions can be synthesized by wet impregnation of nickel ferrite with a palladium salt, and exhibit efficient NO.sub.x adsorption at low temperature, with NO.sub.x desorption occurring predominantly at high temperature. Two-stage NO.sub.x abatement catalysts, effective under engine cold start conditions, include a PNA composition upstream from an NO.sub.x conversion catalyst.

An exhaust gas purification catalyst device has catalyst coating layers, which extend from the upstream side to the downstream side of the exhaust gas flow. The catalyst coating layers each have at least three zones present in order from the upstream side to the downstream side of the exhaust gas flow, and each of these at least three zones is an oxidation catalyst zone or a reduction catalyst zone. In the uppermost layer of an oxidation catalyst zone, the total number of atoms of platinum and palladium is greater than the number of atoms of rhodium; in the upper most layer of a reduction catalyst zone, the number of atoms of rhodium is greater than the total number of atoms of platinum and palladium. The oxidation catalyst zones and the reduction catalyst zones alternate at least twice in the exhaust gas flow direction.

An object is to provide a means for suppressing a deterioration in catalytic performance even after being exposed to high temperature exhaust gas containing a phosphorus compound for a long period of time. An exhaust gas purifying catalyst including palladium supported on cerium-aluminum composite oxide containing cerium at from 3 to 60% by mass in terms of cerium oxide.

An exhaust gas purification catalyst comprises a substrate; a catalyst layer formed on the substrate and containing at least palladium (Pd) and rhodium (Rh) as a metal functioning as an oxidation and/or reduction catalyst. The catalyst also comprises a carrier that supports the metal, and an OSC material having oxygen storage capacity. The catalyst layer has, when disposed in the exhaust pipe, a front section positioned upstream in an exhaust gas flow direction within the exhaust pipe, and a rear section positioned downstream of the front section in the exhaust gas flow direction. The front section contains palladium (Pd) but does not contain the OSC material, and a proportion, at which the front section is formed from an upstream leading end in the exhaust gas flow direction, is 10% to 40% with respect to 100% of a total length of the substrate.