Described are compositions and catalytic articles comprising both a first molecular sieve promoted with copper and a second molecular sieve promoted with iron, the first and second molecular sieves having a d6r unit and the first molecular sieves having cubic shaped crystals with an average crystal size of about 0.5 to about 2 microns. The weight ratio of the copper-promoted molecular sieve to the iron-promoted molecular sieve can be about 1:1 to about 4:1. The catalytic articles are useful in methods and systems to catalyze the reduction of nitrogen oxides in the presence of a reductant.

Synergized platinum group metals (SPGM) with ultra-low PGM loadings employed as close-coupled (CC) three-way catalysts (TWC) systems with varied material compositions and configurations are disclosed. SPGM CC catalysts in which ZPGM compositions of binary or ternary spinel structures supported onto support oxides are coupled with commercialized PGM UF catalysts and tested under Federal Test Procedure FTP-75 within TGDI and PI engines. The performance of the TWC systems including SPGM CC (with ultra-low PGM loadings) catalyst and commercialized PGM UF catalyst is compared to the performance of commercialized PGM CC and PGM UF catalysts. The disclosed TWC systems indicate that SPGM CC TWC catalytic performance is comparable or even exceeds high PGM-based conventional TWC catalysts, with reduced tailpipe emissions.

Synergized platinum group metals (SPGM) with ultra-low PGM loadings employed as underfloor (UF) three-way catalyst (TWC) systems with varied material compositions and configurations are disclosed. SPGM UF catalysts in which ZPGM compositions of binary and ternary spinel structures supported onto support oxides are coupled with commercialized PGM close-coupled (CC) catalysts and tested under Federal Test Procedure FTP-75 within TGDI and PI engines. The performance of the TWC systems including commercialized PGM CC and SPGM UF (with ultra-low PGM loadings) catalysts is compared to the performance of commercialized PGM CC and PGM UF catalysts. The disclosed TWC systems indicate that SPGM UF TWC catalytic performance is comparable or even exceeds high PGM-based conventional TWC catalysts, with reduced tailpipe emissions.

A lean gasoline exhaust treatment catalyst article is provided, the article comprising a catalytic material applied on a substrate, wherein the catalytic material comprises a first composition and a second composition, wherein the first and second compositions are present in a layered or zoned configuration, the first composition comprising palladium impregnated onto a porous refractory metal oxide material and rhodium impregnated onto a porous refractory metal oxide material; and the second composition comprising platinum impregnated onto a porous refractory metal oxide material. Methods of making and using such catalyst articles and the associated compositions and systems employing such catalyst articles are also described.

An object of at least one embodiment of the present invention is to suppress poisoning due to phosphorus derived from engine oil, and effectively purify NOx discharged from the time of engine start up to a high load condition. In an exhaust gas purification catalyst for an internal combustion engine, a catalyst layer includes: a first catalyst layer exposed to an exhaust gas flow; and a second catalyst layer formed between the first catalyst layer and the substrate. A second catalyst upstream layer formed on an upstream side of the second catalyst layer with respect to the exhaust gas flow and a first catalyst downstream layer formed on a downstream side of the first catalyst layer with respect to the exhaust gas flow include at least one of palladium and platinum, as well as an oxygen storage material as the catalyst component. An amount of the oxygen storage material in the first catalyst downstream layer is larger than an amount of the oxygen storage material in the second catalyst upstream layer.

An object is to provide an exhaust gas purification catalyst for an internal combustion engine that can achieve a higher exhaust gas purification performance and a higher engine output performance. A catalyst layer is disposed in an exhaust gas passage, formed on a surface of the substrate, and includes: a first catalyst layer exposed to an exhaust gas flow; and a second catalyst layer formed between the first catalyst layer and the substrate. A catalyst component supported on the first catalyst layer includes rhodium. A catalyst component supported on the second catalyst layer includes at least one of palladium and platinum. The first catalyst layer is formed such that a density of the rhodium supported thereon decreases in a step-like manner through a plurality of segment zones segmented along an exhaust gas flow direction, and the second catalyst layer is formed such that a density of the palladium or the platinum supported thereon decreases in a step-like manner through a plurality of segment zones segmented along the exhaust gas flow direction.

Phosphorus tolerant or resistant three-way catalysts (TWC) are disclosed. The TWC may include a substrate defining a plurality of channels. It may include front and rear washcoat portions overlying the substrate and having respective first and second washcoat loadings, the first washcoat loading being at most 2.0 g/in.sup.3 and less than the second washcoat loading. The front washcoat portion may include a catalyst material supported on a support material comprising a cerium oxide, such as ceria or CZO, or a pre-phosphated material, such as AlPO.sub.4, or CePO.sub.4. In one embodiment, the support material may comprise at least 85 wt. % of a cerium oxide or at least 85 wt. % of a phosphate-containing material. The front portion and the underlying substrate may comprise from 3 to 25 vol. % of the three-way catalyst or the front portion may overly up to an initial 15% of an axial length of the substrate.

A method for processing an edge of a catalyst-supporting honeycomb structure in an exhaust gas denitration apparatus, in which an exhaust gas denitration apparatus equipped with a denitration catalyst-supporting honeycomb structure in which a corrugated plate-like inorganic fiber sheet and a flat plate-like inorganic fiber sheet, each supporting thereon a denitration catalyst containing a silica sol, titania particles, and ammonium metavanadate as a whole primary denitration catalyst layer, are alternately laminated, the edge of gas inlet side of the denitration catalyst-supporting honeycomb structure having the whole primary denitration catalyst layer is dipped in a denitration catalyst-containing slurry for edge processing composed of a silica sol, titania particles or kaolin particles, and ammonium metatungstate to form a coating layer of the denitration catalyst-containing slurry in the edge of the honeycomb structure, and this is dried and then calcinated to form an edge secondary denitration catalyst layer.

The presently claimed invention provides a layered three-way catalyst composition for purification of exhaust gases from internal combustion engines; said catalyst comprises a first layer comprising i) palladium supported on at least one alumina component and at least one oxygen storage component; and ii) barium oxide; wherein said first layer is essentially free of strontium, and a second layer comprising: i) rhodium supported on at least one zirconia component and/or alumina component; ii) strontium oxide and/or barium oxide; and iii) optionally, palladium supported on at least one alumina component. The presently claimed invention also provides a process for preparing the layered three-way catalyst composition which involves a technique such as incipient wetness impregnation technique(A); co-precipitation technique (B); or co-impregnation technique(C). The process includes preparing a first layer; preparing a second layer; and depositing the second layer on the first layer followed by calcination. The presently claimed invention further provides a a layered three-way catalytic article in which the three-way catalyst composition is deposited on a substrate in a layered fashion and its preparation.

The present invention relates to a catalyst comprising a carrier substrate of length L, coating A arranged as the first layer on the carrier and containing platinum on a metal oxide, and coating B applied as the second layer to coating A and containing a Cu-exchanged molecular sieve and no noble metal, wherein the total washcoat quantity of coating A is 40 g/l or more of washcoat in relation to the coated catalyst volume.