A lean NO.sub.x trap catalyst and its use in an emission treatment system for internal combustion engines is disclosed. The lean NO.sub.x trap catalyst comprises a first layer for storing nitrogen oxides (NOx) under lean exhaust gas conditions and releasing and/or reducing stored NOx during rich exhaust gas conditions, and a second layer, said second layer comprising a first zone for oxidizing carbon monoxide (CO) and/or hydrocarbons (HC), and a second zone for oxidizing nitric oxide (NO), and a substrate having an inlet end and an outlet end.

The disclosure relates to a three-way conversion catalyst for the treatment of an exhaust gas comprising nitrogen monoxide, carbon monoxide, and hydrocarbon, wherein the catalyst comprises: (i) a substrate; (ii) a first coating comprising rhodium supported on a first oxidic component; (iii) a second coating comprising palladium supported on a non-zeolitic oxidic material, wherein the non-zeolitic oxidic material comprises manganese and a second oxidic component, wherein the second coating consists of 0 weight-% to 0.001 weight-% of platinum; wherein the first coating is disposed on the substrate over x % of the axial length, with x ranging from 80 to 100; wherein the second coating extends over y % of the axial length from the inlet end to the outlet end and is disposed on the first coating, with y ranging from 20 to x.

The present invention provides a catalyst composition comprising a) platinum; b) rhodium; and c) a ceria-alumina composite, a zirconia composite or a mixture thereof, wherein platinum is supported on the ceria-alumina composite, zirconia composite or mixture thereof, wherein rhodium is supported on the ceria-alumina composite, zirconia composite or mixture thereof, wherein CeO.sub.2 in the ceria alumina composite is 1.0 to 50 wt. %, based on the total weight of the ceria-alumina composite, wherein the amount of ZrO.sub.2 in the zirconia composite is 50 to 99 wt. %, based on the total weight of the zirconia composite. The present invention also provides a catalytic article comprising the catalyst composition and its preparation.

The present disclosure provides msect-4 molecular sieves with OFF and ERI topologies, a preparation method therefor, and applications thereof. An eight-membered ring small pore molecular sieve used as a raw material is dispersed in an aqueous phase. Following that, caustic potash, an aluminum source, and an organic structure-directing agent (OSDA) are added. The pH value is then adjusted to be greater than 10, and a silicon source is introduced to attain the desired silicon-aluminum ratio, followed by stirring reaction, aging, crystallization, filtration, washing, ammonia exchange reaction, drying, and calcination. The msect-4 molecular sieves with OFF and ERI topologies, the preparation method therefor, and applications exhibit excellent hydrothermal stability, a plurality of adsorption sites exposed by a regular bone-like structure, and a large specific surface area. Consequently, this molecular sieves find applicability across various technical fields including selective catalytic reduction, passive adsorption, and catalytic cracking, and has broad application prospects.

The present invention provides an exhaust gas purifying catalyst including a first catalyst layer (12). The first catalyst layer (12) includes a first section (14) and a second section (15) in an exhaust gas flow direction, the first section (14) being located on an upstream side in the exhaust gas flow direction relative to the second section (15). The first section (14) and the second section (15) both contain a catalytically active component including a specific element. A concentration of the specific element is higher in the first section (14) than in the second section (15). A concentration gradient of the specific element contained in the first section (14) in a thickness direction of the catalyst layer (12) is milder than a concentration gradient of the specific element contained in the second section (15) in the thickness direction.

An object of the present invention is to provide means for improving the hydrogen generation properties of a hydrogen-producing catalyst. A hydrogen-producing catalyst according to one aspect of the present invention comprises Rh and a composite containing Al, Ce, and Zr. When a ratio of the number of Al atoms to the number of Ce atoms (Al/Ce) in the composite measured by X-ray fluorescence (XRF) analysis is R.sub.1 and a ratio of the number of Al atoms to the number of Ce atoms (Al/Ce) in the composite measured by an X-ray photoelectron spectroscopy (XPS) method is R.sub.2, a value of R.sub.2/R.sub.1 is greater than 2.25 and less than 5.92.

The present invention relates to a NOx storage material comprising a cerium-based mixed oxide comprising cerium, oxygen, and a first rare earth metal other than cerium, wherein said NOx storage material further comprises a second rare earth metal other than cerium; wherein said first rare earth metal is different to said second rare earth metal; and wherein said second rare earth metal is disposed or supported on the surface of the cerium-based mixed oxide.

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.

This invention relates to an aqueous dispersion of particles, the dispersion having a particle content of 10-70 wt %, and the particles comprising, on an oxide basis: (a) 10-98 wt % in total of ZrO.sub.2+HfO.sub.2, and (b) 2-90 wt % in total of AI.sub.2O.sub.3, CeO.sub.2, La.sub.2O.sub.3, Nd.sub.2O.sub.3, Pr.sub.6O.sub.11, Y.sub.2O.sub.3, or a transition metal oxide, wherein the dispersion has a Z-average particle size of 100-350 nm and the particles have a crystallite size of 1-9 nm. The invention also relates to a substrate coated with the aqueous dispersion of particles.