An exhaust gas purification device has a metal substrate and a catalyst layer on the metal substrate, wherein the metal substrate is a wound body of one or a plurality of metal foils, at least one of the one or a plurality of metal foils is a perforated metal foil having holes, the catalyst layer contains noble metal catalyst particles and a carrier for carrying the noble metal catalyst particles, and more noble metal catalyst particles are present in the catalyst layer on side surfaces of holes, which face an upstream side of an exhaust gas flow, than in the catalyst layer on side surfaces of holes, which face a downstream side of the exhaust gas flow.

The present disclosure generally provides catalyst compositions, articles and methods for reducing levels of HC, CO and NO.sub.x in an exhaust gas stream using the catalyst compositions and catalytic articles. The compositions, which are doped with niobium oxide, significantly improve the performance of a three-way catalyst when used as the rhodium support while strictly controlling the amount of precious metal loading.

A catalyst material for abatement of exhaust gas emissions from a lean burn engine is provided, the catalyst material including a metal-exchanged SAPO-34 material, and an oxide layer at least partially covering an outside surface of the SAPO-34 material, wherein the oxide layer is not substantially blocking the pores of the SAPO-34 material.

A catalyst powder according to the present invention is a catalyst powder that includes: a core portion that contains ceria and zirconia; and a surface layer portion that is located on the core portion and contains ceria and zirconia. The ratio (M.sub.2/M.sub.1) is 0.30 or more and 0.95 or less, the ratio (M.sub.2/M.sub.1) being the ratio of a mole fraction M.sub.2 (mol %) of cerium in the surface layer portion measured using X-ray photoelectron spectroscopy to a mole fraction M.sub.1 (mol %) of cerium in the entire powder. It is preferable that the ratio (M.sub.4/2/M.sub.3/1) between M.sub.3/1 and M.sub.4/2 is 1.1 or more and 5.0 or less, wherein M.sub.3/1 (=M.sub.3/M.sub.1) represents the ratio between a mole fraction M.sub.3 (mol %) of zirconium in the entire powder and a mole fraction M.sub.1 (mol %) of cerium in the entirety of the powder, and M.sub.4/2 (=M.sub.4/M.sub.2) represents the ratio between a mole fraction M.sub.4 (mol %) of zirconium measured using X-ray photoelectron spectroscopy and a mole fraction M.sub.2 (mol %) of cerium measured using X-ray photoelectron spectroscopy.

Various structures for catalytic convertors are disclosed herein. The device includes an outer housing enclosing a catalytic core. The catalytic core can be formed in a myriad of ways. Flow paths through the core are constructed so that they are not straight-line paths from the inlet of the device to the outlet of the device. Zigzag conformations and stacked panel arrays are described that maximize the catalytic surface area in a given volume of housing.

An automotive catalytic converter includes a three-way catalyst having Rh as the only precious metal configured as a front zone and a three-way catalyst having a mixture of Rh and Pd, Pt, or both configured as a rear zone, such that an exhaust gas from an internal combustion engine passes through the front zone before passing through the rear zone to minimize sulfur poisoning of the catalytic converter.

A catalytic converter for an internal combustion engine has a housing (2) and a catalyst element (12) formed in the housing (2). The housing (2) is formed such that exhaust gas of the internal combustion engine can flow through the housing (2). The catalyst element (12) is formed such that fluid can flow around and through it. Additionally, the catalyst element (12) has a plurality of ribs (15) on its surface (14) that faces the exhaust gas.

Provided is a novel exhaust gas purification catalyst, which uses a Cu-based delafossite oxide, capable of increasing the exhaust gas purification performance compared to the case of using the Cu-based delafossite oxide alone. Proposed is an exhaust gas purification catalyst comprising a delafossite-type oxide represented by a general formula ABO.sub.2 and an inorganic porous material, wherein Cu is contained in the A site of the general formula of the delafossite oxide, one or two or more elements selected from the group consisting of Mn, Al, Cr, Ga, Fe, Co, Ni, In, La, Nd, Sm, Eu, Y, V, and Ti are contained in the B site thereof, and Cu is contained in 3 to 30% relative to the total content (mass) of the delafossite-type oxide and the inorganic porous material.

An exhaust system for a compression ignition engine comprising an oxidation catalyst for treating carbon monoxide (CO) and hydrocarbons (HCs) in exhaust gas from the compression ignition engine, wherein the oxidation catalyst comprises: a platinum group metal (PGM) component selected from the group consisting of a platinum (Pt) component, a palladium (Pd) component and a combination thereof; an alkaline earth metal component; a support material comprising a modified alumina incorporating a heteroatom component; and a substrate, wherein the platinum group metal (PGM) component, the alkaline earth metal component and the support material are disposed on the substrate.

An object of the present invention is to provide a chabazite zeolite which does not easily peel from a substrate such as a honeycomb body even when the substrate has been coated therewith, while exhibiting excellent durability. The present invention relates to a chabazite zeolite for substrate coating, which includes (i) to (iv) below. (i) Si and Al are contained, (ii) an SiO.sub.2/Al.sub.2O.sub.3 molar ratio is in a range of 5<SiO.sub.2/Al.sub.2O.sub.3<10, (iii) an average crystal size is in a range of 0.05 m<average crystal size<1 m, and (iv) in a spectrum measured by .sup.27Al-NMR, a ratio (A.sub.NFA/A.sub.Total) between an area (A.sub.Total) of all peaks in the spectrum and an area (A.sub.NFA) of peaks assigned to Al other than tetracoordinated Al is in a range of 20%(A.sub.NFA/A.sub.Total)70%.