Abstract: An exhaust gas purification device includes a substrate including an upstream end and a downstream end, the substrate having a length Ls between the upstream end and the downstream end; a first catalyst layer containing first catalyst particles, extending across a first region, and being in contact with the substrate, the first region extending between the upstream end and a first position, the first position being at a first distance La from the upstream end toward the downstream end; and a second catalyst layer containing second catalyst particles, extending across a second region, and being in contact with the substrate, the second region extending between the downstream end and a second position, the second position being at a second distance Lb from the downstream end toward the upstream end. The first catalyst layer has an inner surface defining macropores.

Abstract: A composite oxidation catalyst (18, 20) for use in an exhaust system for treating an exhaust gas produced by a vehicular compression ignition internal combustion engine (30) and upstream of a particulate matter filter (44, 50) in the exhaust system comprises a substrate (5) having a total length L and a longitudinal axis and having a substrate surface extending axially between a first substrate end (I) and a second substrate end (O); and three or more catalyst washcoat zones (1, 2, 3; or 1, 2, 3, 4) arranged axially in series on and along the substrate surface, wherein a first catalyst washcoat zone (1) having a length L1, wherein L1<L, is defined at one end by the first substrate end (I) and at a second end by a first end (19, 21) of a second catalyst washcoat zone (2) having a length L2, wherein L2<L, wherein the first catalyst washcoat zone (1) comprises a first refractory metal oxide support material and two or more platinum group metal components supported thereon comprising both platinum and palla

Abstract: The present invention relates to a diesel oxidation catalyst comprising a carrier substrate, and a first washcoat layer disposed on the substrate, the first washcoat layer comprising palladium supported on a support material comprising a metal oxide, gold supported on a support material comprising a metal oxide, and a ceria comprising compound, as well as a process for the preparation of such catalyst.

Abstract: 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.

Abstract: Described are SCR catalyst systems comprising a first SCR catalyst composition and a second SCR catalyst composition arranged in the system, the first SCR catalyst composition promoting higher N2 formation and lower N2O formation than the second SCR catalyst composition, and the second SCR catalyst composition having a different composition than the first SCR catalyst composition, the second SCR catalyst composition promoting lower N2 formation and higher N2O formation than the first SCR catalyst composition. The SCR catalyst systems are useful in methods and systems to catalyze the reduction of nitrogen oxides in the presence of a reductant.

Abstract: A honeycomb structural body and a method for the manufacturing thereof. The manufacturing method includes (i) providing a plurality of silicon carbide honeycomb segments, each having a cell structure and at least one outer wall; (ii) subjecting the honeycomb segments to an oxidizing thermal treatment forming a surface layer of silicon oxides on the at least one outer wall; and (iii) bonding the plurality of oxidized honeycomb segments so as to form the honeycomb structural body in the substantial absence of organic binders with the interposition of a sealing material including a mixture of one or more silicon carbide powders, one or more ceramic fibers, and one or more inorganic binders.

Abstract: An ammonia oxidation catalyst being superior in heat resistance and capable of suppressing by-production of N2O or NOx. The ammonia oxidation catalyst is made by coating at least two catalyst layers having a catalyst layer (lower layer) including a catalyst supported a noble metal on an inorganic base material including any of a composite oxide (A) having at least titania and silica as main components, alumina, and a composite oxide (B) consisting of alumina and silica; and a catalyst layer (upper layer) including a composite oxide (C) consisting of at least silica, tungsten oxide, ceria and zirconia, at the surface of an integral structure-type substrate, wherein a composition of the composite oxide (C) is silica: 20% by weight or less, tungsten oxide: 1 to 50% by weight, ceria: 1 to 60% by weight, and zirconia: 30 to 90% by weight.

Abstract: The invention provides an exhaust gas cleaning oxidation catalyst and in particular to an oxidation catalyst for cleaning the exhaust gas discharged from internal combustion engines of compression ignition type (particularly diesel engines). The invention further relates to a catalysed substrate monolith comprising an oxidising catalyst on a substrate monolith for use in treating exhaust gas emitted from a lean-burn internal combustion engine. In particular, the invention relates to a catalysed substrate monolith comprising a first washcoat coating and a second washcoat coating, wherein the second washcoat coating is disposed in a layer above the first washcoat coating.

Abstract: An exhaust gas catalyst where the catalyst efficiency is improved by enhancing diffusion of the exhaust gas in a catalyst layer. An exhaust gas catalyst comprises at least a carrier and a plurality of layers formed on the carrier. At least one of the layers has pores therein, and at least one other layer has pores therein and contains, as catalyst components, a noble metal, alumina and a complex oxide mainly containing ceria, zirconia and one or more rare earth elements other than cerium.

Abstract: A treatment device configured to receive a flow of exhaust from a power source is disclosed. The treatment device may have a first layer, a second layer, and a substrate layer. The first layer may include a selective catalytic reduction layer, and the second layer may be disposed downstream of the first layer and include an oxidation catalyst support. The substrate layer may be disposed adjacent to the second layer. Additionally, an additive may be disposed downstream of the first layer. The additive may be operative to substantially prohibit migration of a component of the second layer to the first layer upon treatment of the flow of exhaust by the oxidation catalyst support.

Abstract: Described are catalyst compositions, catalytic articles, methods of manufacturing catalytic articles and exhaust gas treatment systems and methods that utilize the catalytic articles. The catalyst composition comprises an oxidation catalyst comprising a washcoat layer including a platinum group metal supported on a refractory metal oxide support and porous molecular sieve particles having internal pores, the molecular sieve particles protected by a protecting material selected from an organic wax encapsulating the molecular sieve particles, a polymer encapsulating the molecular sieve particles, an inorganic oxide deposited on the surface of the molecular sieve particles, or an organic compound filling the internal pores of the molecular sieve particles, wherein the protecting material prevents interaction of the molecular sieve particles with the platinum group metal.

Abstract: Disclosed herein is a layered three-way catalytic system being separated in a front and a rear portion having the capability of simultaneously catalyzing the oxidation of hydrocarbons and carbon monoxide and the reduction of nitrogen oxides. Provided is a catalyst composite comprising a single front catalytic layer and two rear catalytic layers in conjunction with a substrate, where the single font layer and the rear bottom layer comprise a Pd component, the rear top layer comprises a Rh component, and the rear bottom layer is substantially free of an oxygen storage component (OSC).

Abstract: Systems and Methods for manufacturing ZPGM catalysts systems that may allow the prevention of formation or the conversion of corrosion causing compounds, such as hexavalent chromium compounds, within ZPGM catalyst systems are disclosed. ZPGM catalysts systems, may include metallic substrate, which may include alloys of iron and chromium, a washcoat and an overcoat. Disclosed manufacturing processes may include a thermal decomposition of hexavalent chromium compounds which may allow the decomposition of such compounds into trivalent chromium compounds, and may also produce metallic catalyst, such as silver.

Abstract: Disclosed is a gas purifying catalyst for an internal combustion engine comprising: a carrier and a catalyst layer formed on the carrier, the catalyst layer including a first catalyst, a second catalyst and a third catalyst. The first catalyst comprises Pd supported in a first support, the first support comprising alumina. The second catalyst comprises Rh supported in a second support, the second support comprising a complex oxide of ceria-zirconia. The third catalyst comprising Pd supported in a third support, the third support comprising a complex oxide of ceria-zirconia.

Abstract: An exhaust emission control catalyst disclosed herein is equipped with a rhodium catalytic layer and a platinum catalytic layer, and is characterized in that a relationship between a mole average (X) of a Pauling's electronegativity that is calculated as to elements included in the rhodium catalytic layer except platinum group elements and oxygen and a mole average (Y) of a Pauling's electronegativity that is calculated as to elements included in the platinum catalytic layer except platinum group elements and oxygen is 1.30?X?1.45 and 1.47?Y?2.0. According to this exhaust emission control catalyst, an interlayer transfer of platinum and/or rhodium and the alloying of platinum and/or rhodium are suppressed during use of the catalyst, and high exhaust gas purification performance can be exerted.

Abstract: A catalytically active particulate filter is proposed which is suitable for use in an exhaust gas cleaning system for diesel engines. The particulate filter removes diesel soot particles from the exhaust gas and is also effective to oxidize carbon monoxide and hydrocarbons and to convert nitrogen monoxide at least proportionally into nitrogen dioxide. The particulate filter comprises a filter body (3) and two catalytically active coatings (1) and (2) which contain platinum and palladium, or platinum or palladium respectively, wherein the platinum content of the second catalytically active coating (2) is higher than the platinum content of the first catalytically active coating (1).

Abstract: An exhaust gas-purifying catalyst includes a support provided with one or more through-holes through which exhaust gas flows, and a catalytic layer supported by the support and containing an oxygen storage material. The exhaust gas-purifying catalyst includes a first section to which the exhaust gas is supplied, and a second section to which the exhaust gas having passed through the first section is supplied. The catalytic layer includes a layered structure of a first catalytic layer containing platinum and/or palladium and a second catalytic layer containing rhodium in the first catalytic section and further includes a third layer containing rhodium in the second section. The second section is smaller in oxygen storage material content per unit volumetric capacity than the first section.

Abstract: A catalyst for the selective catalytic reduction of nitrogen oxides in diesel engine exhaust gases using ammonia or a precursor compound decomposable to ammonia. The catalyst includes two superposed coatings applied to a support body, of which the first coating applied directly to the support body includes a transition metal-exchanged zeolite and/or a transition metal-exchanged zeolite-like compound, and effectively catalyzes the SCR reaction. The second coating is applied to the first coating to cover it on the exhaust gas side and prevent hydrocarbons having at least three carbon atoms present in the exhaust gas from contacting the first coating, without blocking the passage of nitrogen oxides and ammonia to the first coating. The second coating may be formed from small-pore zeolites and/or small-pore, zeolite-like compounds, and from suitable oxides, especially silicon dioxide, germanium dioxide, aluminum oxide, titanium dioxide, tin oxide, cerium oxide, zirconium dioxide and mixtures thereof.

Abstract: The present invention relates to a catalyst composition comprising a carrier substrate, a layer (i) coated on said carrier substrate comprising at least one precious group metal, a layer (ii) comprising Rh, and a layer (iii) comprising Pd and/or Pt and being substantially free of Ce, Ba and Rh, wherein the layer (iii) has a lower weight than the layer (i) or the layer (ii). Furthermore, the present invention relates to a method for treating an exhaust gas stream using said catalyst composition.

Abstract: Ammonia oxidation catalyst being superior in heat resistance and capable of suppressing by-production of N2O and leakage of ammonia. The ammonia oxidation catalyst (AMOX) removes surplus ammonia, in selectively reducing nitrogen oxides by adding urea or ammonia and using a selective catalytic reduction (SCR) catalyst, into exhaust gas, wherein the ammonia oxidation catalyst is made by coating at least two catalyst layers having a catalyst layer (lower layer) including a catalyst supported a noble metal element on a composite oxide (A) having titania and silica as main components, and a catalyst layer (upper layer) including a composite oxide (C) consisting of tungsten oxide, ceria, and zirconia, at the surface of an integral structure-type substrate, wherein a composition of the composite oxide (C) is tungsten oxide: 1 to 50% by weight, ceria: 1 to 60% by weight, and zirconia: 30 to 90% by weight.

Abstract: A catalyst and method of forming the catalyst includes a catalyst body having hydrocarbon adsorber material and oxygen storage capacity material disposed thereon.

Abstract: Described is a catalyzed soot filter wherein the inlet coating of the filter comprises an oxidation catalyst comprising platinum (Pt) and optionally palladium (Pd), wherein the outlet coating of the filter comprises an oxidation catalyst comprising Pd and optionally Pt, wherein the Pt concentration in the outlet coating is lower than the Pt concentration in the inlet coating and wherein the weight ratio of Pt:Pd in the outlet coating is in the range of from 0:1 to 2:1; and wherein the inlet coating and the outlet coating are present on the wall flow substrate at a coating loading ratio in the range of from 0.5 to 1.5, calculated as ratio of the loading of the inlet coating (in g/inch3 (g/(2.54 cm)3)):loading of the outlet coating (in g/inch3 (g/(2.54 cm)3)). Systems include such catalyzed soot filters, methods of diesel engine exhaust gas treatment and methods of manufacturing catalyzed soot filters are also described.

Abstract: Oxidation ZPGM catalyst systems and three way ZPGM catalyst systems are disclosed. ZPGM catalyst systems may oxidize toxic gases, such as carbon monoxide and hydrocarbons, optionally some ZPGM catalyst systems may as well reduce nitrogen oxides that may be included in exhaust gases. ZPGM catalyst systems may include: a substrate, a washcoat, and an overcoat. The washcoat may include at least one ZPGM catalyst and carrier material oxides. Similarly, overcoat may include at least one ZPGM catalyst, carrier material oxides and OSMs. Suitable known in the art chemical techniques, deposition methods and treatment systems may be employed in order to form the disclosed ZPGM catalyst systems.

Abstract: An exhaust gas purification catalyst has a substrate, a lower catalyst layer that is formed on the substrate and contains at least one of Pd and Pt, and an upper catalyst layer that is formed on the lower catalyst layer and contains Rh. A region that does not contain the upper catalyst layer is disposed on the exhaust gas upstream side of this exhaust gas purification catalyst. The lower catalyst layer includes a front-stage lower catalyst layer on the exhaust gas upstream side and a rear-stage lower catalyst layer on the exhaust gas downstream side. The front-stage lower catalyst layer contains an oxygen storage material.

Abstract: Catalyst articles comprising substantially only a palladium precious metal component in a first catalytic layer and a rhodium component in a second catalytic layer and related methods of preparation and use are disclosed. Also disclosed is a catalyst article comprising a first layer formed on a carrier substrate, wherein the first layer comprises a refractory metal oxide and has a surface that is substantially uniform; a second layer formed on the first layer, wherein the second layer comprises i) an oxygen storage component that is about 50-90% by weight of the second layer and ii) a palladium component in an amount of about 2-5% by weight of the second layer, wherein the palladium component is substantially the only platinum group metal component, and a palladium-free third layer comprising a rhodium component supported on a thermostable oxygen storage component which is about 80-99% by weight of the second layer. One or more improved properties are exhibited by the catalyst article.

Abstract: Catalyst articles comprising palladium and related methods of preparation and use are disclosed. Disclosed is a catalyst article comprising a first catalytic layer formed on a substrate, wherein the first catalytic layer comprises palladium impregnated on a ceria-free oxygen storage component and platinum impregnated on a refractory metal oxide, and a second catalytic layer formed on the first catalytic layer comprising platinum and rhodium impregnated on a ceria-containing oxygen storage component. The palladium component of the catalyst article is present in a higher proportion relative to the other platinum group metal components. The catalyst articles provide improved conversion of carbon monoxide in exhaust gases, particularly under rich engine operating conditions.

Abstract: The exhaust gas purification catalyst according to the present invention has a substrate 54, a lower layer 57 disposed on this substrate 54, and an upper layer 58 disposed on this lower layer 57. The upper layer 58 is provided with a first catalyst and a second catalyst, and the lower layer 57 is provided with a first catalyst. This first catalyst has Al2O3 as a carrier and Pt and Pd as noble metals supported on the Al2O3, while the second catalyst typically has an Al2O3—ZrO2—TiO2 complex oxide as a carrier and has Pd as a noble metal supported on the Al2O3—ZrO2—TiO2 complex oxide. Moreover, the upper layer 58 has a hydrocarbon adsorbent 68.

Abstract: A layered catalyst including a surface axis including a catalyst material layer, and a substrate material layer contacting the catalyst material layer. The catalyst material layer includes a compressed atomic distance between two adjacent catalyst atoms along the surface axis relative to an atomic distance of the same catalyst material as in bulk. The substrate material has a higher surface energy than the catalyst material. In certain instances, at least 70 percent of total atoms of the catalyst material are in a film growth mode. In certain other instances, a surface free energy of the substrate material is 1 to 50 percent greater than a surface free energy of the catalyst material. In yet certain other instances, the catalyst material layer has a d-band center in a range of ?2.1 eV to ?2.25 eV.

Abstract: An exhaust system, and a catalyzed substrate for use in an exhaust system, is disclosed. The exhaust system comprises a lean NOx trap and the catalyzed substrate. The catalyzed substrate has a first zone, having a platinum group metal loaded on a support, and a second zone, having copper or iron loaded on a zeolite. The first zone or second zone additionally comprises a base metal oxide or a base metal loaded on an inorganic oxide. Also provided are methods for treating an exhaust gas from an internal combustion engine using the exhaust system. The exhaust system is capable of storing NH3 generated in rich purging, reacting the NH3 with slip NOx, controlling H2S released from NOx trap desulfation, and oxidizing slip hydrocarbons and carbon monoxide. When the catalyzed substrate is a filter substrate, it is also capable of removing soot from exhaust system.

Abstract: An exhaust gas purification catalyst is provided with a catalyst coating layer (40) formed on the surface of a substrate (32). This catalyst coating layer (40) is formed of an upper catalyst coating layer (36) in which Rh particles are supported on a porous support, and a lower catalyst coating layer (34) in which Pd particles are supported on a support that contains an ACZ composite oxide made of alumina (Al2O3), ceria (CeO2), and zirconia (ZrO2).

Abstract: The present invention relates to a nitrogen oxide storage catalyst comprising: a substrate; a first washcoat layer disposed on the substrate, the first washcoat layer comprising metal oxide support particles and a nitrogen oxide storage material comprising at least one metal compound selected from the group consisting of alkaline earth metal compounds, alkali metal compounds, rare earth metal compounds, and mixtures thereof, at least a portion of said at least one metal compound being supported on the metal oxide support particles; and a second washcoat layer disposed over the first washcoat layer, said second washcoat layer comprising Rh, wherein the first washcoat layer contains substantially no Rh, and wherein the second washcoat layer is disposed on 100-x % of the surface of the first washcoat layer, x ranging from 20 to 80.

Abstract: An emission control catalyst includes copper-ceria to boost low temperature CO oxidation performance, generate exothermic heat during the process, and reduce HC and NOx emissions. As a result, system performance is boosted at equal catalyst cost or maintained at a reduced catalyst cost. In one embodiment, an engine exhaust catalyst includes a first washcoat layer having at least one of a platinum-based catalyst, a palladium-based catalyst, and combinations thereof; and a second washcoat layer having copper-ceria.

Abstract: The invention relates to a catalyst for removal of nitrogen oxides from the exhaust gas of diesel engines, and to a process for reducing the level of nitrogen oxides in the exhaust gas of diesel engines. The catalyst consists of a support body of length L and of a catalytically active coating which in turn may be formed from one or more material zones. The material zones comprise a copper-containing zeolite or a zeolite-like compound. The materials used include chabazite, SAPO-34, ALPO-34 and zeolite ?. In addition, the material zones comprise at least one compound selected from the group consisting of barium oxide, barium hydroxide, barium carbonate, strontium oxide, strontium hydroxide, strontium carbonate, praseodymium oxide, lanthanum oxide, magnesium oxide, magnesium/aluminum mixed oxide, alkali metal oxide, alkali metal hydroxide, alkali metal carbonate and mixtures thereof. Noble metal may optionally also be present in the catalyst.

Abstract: Systems and methods are provided for a layered emission control device coupled to an exhaust manifold. Various formulations may be incorporated in a plurality of layers of the device to enable various emission control functions to be grouped within spatial constraints. For example, a first layer may include a first, oxidizing catalyst, a second layer may include a HC trap, and a third layer may include a second, different oxidizing catalyst, the second layer positioned between the first and third layers. The layers may be organized to reduce functional interference and improve functional synergy between the various emission control functions.

Abstract: A NOx storage component comprises caesium silicate (Cs2SiO3) and at least one platinum group metal. The invention also includes a NOx absorber catalyst comprising a NOx storage component according to the invention disposed on a substrate monolith; a method of treating exhaust gas containing NOx from a lean burn internal combustion engine comprising the steps of contacting a NOx storage component comprising caesium silicate (Cs2SiO3) and at least one platinum group metal with lean exhaust gas containing NOx to adsorb NOx thereon; and periodically desorbing adsorbed NOx by contacting the NOx storage component with stoichiometric or rich exhaust gas; and a method of making a NOx storage component according to the invention comprising the steps of combining and reacting an aqueous salt of at least one platinum group metal, an aqueous caesium salt and a source of silica.

Abstract: Described is a nitrogen oxide storage catalyst comprising: a substrate; a first washcoat layer provided on the substrate, the first washcoat layer comprising a nitrogen oxide storage material, a second washcoat layer provided on the first washcoat layer, the second washcoat layer comprising a hydrocarbon trap material, wherein the hydrocarbon trap material comprises substantially no element or compound in a state in which it is capable of catalyzing selective catalytic reduction, preferably wherein the hydrocarbon trap material comprises substantially no element or compound in a state in which it is capable of catalyzing a reaction wherein nitrogen oxide is reduced to N2, said catalyst further comprising a nitrogen oxide conversion material which is either comprised in the second washcoat layer and/or in a washcoat layer provided between the first washcoat layer and the second washcoat layer.

Abstract: Catalytic articles, systems and methods for treating exhaust gas streams are described. A catalytic article comprising a wall flow filter having gas permeable walls, a hydrolysis catalyst, an optional soot oxidation catalyst, a selective catalytic reduction catalyst permeating the walls, an ammonia oxidation catalyst and an oxidation catalyst to oxidize CO and hydrocarbons is described. Methods of treating exhaust gas streams comprising soot, an ammonia precursor such as urea, ammonia, NOx, CO and hydrocarbons are also provided.

Abstract: An exhaust gas purifying catalyst that contains a first oxygen storage material on which no noble metal is supported and which has a pyrochlore phase type regular array structure, and a second oxygen storage material which has a higher oxygen storage rate and a lower oxygen storage capacity than the first oxygen storage material and on which a platinum group noble metal is supported.

Abstract: The invention provides a catalyst for catalytically removing three components, which are carbon monoxide, hydrocarbons and nitrogen oxides, from combustion exhaust gas generated by combusting fuel at around the stoichiometric air to fuel ratio. The catalyst includes: (A) a first catalyst component including at least rhodium, platinum, or palladium in a content of 0.01 to 0.5% by weight; and (B) a second catalyst component, which is the remainder, including a composite oxide or a mixed oxide including (a) at least zirconium oxide or titanium oxide, and (b) an oxide of at least praseodymium, yttrium, neodymium, tungsten, niobium, silicon, or aluminum, wherein the content of the oxide (a) in the composite oxide or the mixed oxide is in a range of 70 to 95% by weight. The invention further provides a two-layer catalyst that includes a surface catalyst layer containing the above-mentioned catalyst.

Abstract: An exhaust system 10 for a vehicular lean-burn internal combustion engine comprises: (a) a first substrate monolith 6 comprising a SCR catalyst; (b) at least one second substrate monolith 4 comprising a catalytic washcoat coating comprising at least one platinum group metal (PGM) disposed upstream of the first substrate monolith; and (c) a third substrate monolith 2 disposed between the first substrate monolith and the or each second substrate monolith, wherein at least one PGM on the or each second substrate monolith 4 is liable to volatilise when the or each second substrate monolith 4 is exposed to relatively extreme conditions including relatively high temperatures, and wherein the third substrate monolith 2 comprises a washcoat coating comprising at least one metal oxide for trapping volatilised PGM.

Abstract: A catalysed substrate monolith 12 for use in treating exhaust gas emitted from a lean-burn internal combustion engine, which catalysed substrate monolith 12 comprising a first washcoat coating 16 and a second washcoat coating 18, wherein the first washcoat coating comprises a catalyst composition comprising at least one platinum group metal (PGM) and at least one support material for the at least one PGM, wherein at least one PGM in the first washcoat coating is liable to volatilize when the first washcoat coating is exposed to relatively extreme conditions including relatively high temperatures, wherein the second washcoat coating comprises at least one metal oxide for trapping volatilized PGM and wherein the second washcoat coating is oriented to contact exhaust gas that has contacted the first washcoat coating.

Abstract: A double-layer three-way catalyst for purification of the exhaust gases from internal combustion engines which has excellent activity and thermal stability is described. The catalyst contains active aluminum oxide and a first cerium/zirconium mixed oxide which are both catalytically activated with palladium in the first layer applied to a catalyst support. In the second layer which is in direct contact with the exhaust gas, the catalyst likewise contains an active aluminum oxide and a second cerium/zirconium mixed oxide which are both catalytically activated with rhodium. The second cerium/zirconium mixed oxide has a higher zirconium oxide content than the first mixed oxide.

Abstract: The invention provides an exhaust gas cleaning oxidation catalyst and in particular to an oxidation catalyst for cleaning the exhaust gas discharged from internal combustion engines of compression ignition type (particularly diesel engines). The invention further relates to a catalysed substrate monolith comprising an oxidizing catalyst on a substrate monolith for use in treating exhaust gas emitted from a lean-burn internal combustion engine. In particular, the invention relates to a catalysed substrate monolith comprising a first washcoat coating and a second washcoat coating, wherein the second washcoat coating is disposed in a layer above the first washcoat coating.

Abstract: Disclosed herein is a catalytically active particulate filter, an exhaust gas cleaning system and a process for cleaning the exhaust gases of predominantly stoichiometrically operated internal combustion engines, which are suitable, as well as the gaseous CO, HC and NOx pollutants, also for removing particulates from the exhaust gas. The particulate filter comprises a filter body and a catalytically active coating consisting of two layers. The first layer is in contact with the incoming exhaust gas, the second layer with the outgoing exhaust gas. Both layers contain alumina. The first layer contains palladium. The second layer contains, in addition to rhodium, an oxygen-storing cerium/zirconium mixed oxide.

Abstract: The present invention is an exhaust gas purification catalyst equipment, and a method of use thereof, formed by arranging a selective catalytic reduction type catalyst for purifying nitrogen oxides in exhaust gas exhausted from lean combustion engines using ammonia or urea as a reducing agent, it is provided with a selective catalytic reduction type catalyst, characterized in that said catalyst comprises a lower-layer catalyst layer (A) having an oxidative function for nitrogen monoxide (NO) in exhaust gas and an upper-layer catalyst layer (B) having an adsorbing function for ammonia on the surface of a monolithic structure type carrier (C), and that the lower-layer catalyst layer (A) comprises a noble metal component (i), an inorganic base material constituent (ii) and zeolite (iii), and the upper-layer catalyst layer (B) comprises substantially none of component (i) but the component (iii), in a flow path of exhaust gas, characterized in that a spraying means to supply an urea aqueous solution or an aqueous

Abstract: Provided are exhaust systems and components suitable for use in conjunction with gasoline engines to treat gaseous emissions such as hydrocarbons, nitrogen oxides, and carbon monoxides. Layered three-way conversion (TWC) catalysts comprise an outer layer whose rhodium is supported by an oxygen storage component, such as a ceria-zirconia composite, and the outer layer is substantially free from alumina as a support. The rhodium-containing layer can be free of all other precious metals, such as platinum and palladium. A lower palladium layer is provided where the palladium is supported by a refractory metal oxide. The lower palladium layer can be free of rhodium and platinum and can contain an oxygen storage component that is the same or different from that in the rhodium-containing layer. Methods of making and using these catalysts are also provided.

Abstract: An exhaust gas purifying catalyst is constituted by: noble metal particles (1); first compounds (2) which support the noble metal particles (1); second compounds (3) different in type from the first compounds (2); and oxides (4) which surround the noble metal particles (1), the first compounds (2) and the second compounds (3). A median diameter of the first compounds (2) and a median diameter of the second compounds (3) satisfy a relationship of a following inequality: median diameter of first compounds<median diameter of second compounds.

Abstract: An automobile exhaust gas catalytic converter includes a first catalyst layer; a second catalyst layer located on a downstream side as compared to the first catalyst layer; and a base material on which the first catalyst layer and the second catalyst layer are respectively located. In the exhaust gas catalytic converter, the proportion (LB/LS) of a coating length (LB) of the second catalyst layer from a downstream end of the base material with respect to a total length (LS) of the base material in the exhaust gas flow direction is approximately 50 to 90%, the proportion of an amount of Rh contained in the second catalyst layer with respect to a total amount of Rh contained in the first catalyst layer and the second catalyst layer is approximately 50 to 90% by mass, and the rest of Rh is contained together with Pd or Pt in the first catalyst layer.

Abstract: An exhaust gas-purifying catalyst according to the present invention includes a substrate, a first catalytic layer facing the substrate and includes at least one precious metal selected from the group consisting of palladium and platinum, and alumina doped with an alkaline-earth metal element, and a second catalytic layer facing the substrate with the first catalytic layer interposed therebetween or intervening between the substrate and the first catalytic layer, the second catalytic layer includes rhodium and alumina doped with the alkaline-earth metal element.

Abstract: A cerium-zirconium composite metal oxide having improved durability at high temperature and a stable oxygen storage capacity is provided. The cerium-zirconium composite metal oxide is characterized in that the total mole number of Ce and Zr is at least 85% based on the total mole number of metal in the composite metal oxide, a molar ratio Ce/Zr is within a range from 1/9 to 9/1, and an isoelectric point of the composite metal oxide is more than 3.5. Preferably, the molar ratio Ce/Zr is within a range from 3/7 to 7/3 and the isoelectric point is within a range from 3.8 to 5.0, and the cerium-zirconium composite metal oxide contains a rare earth metal (excluding Ce) in a concentration of less than 15% by mole based on the total mole number of metal in the composite metal oxide. Also the present invention provides a cerium-zirconium composite metal oxide, characterized in that CeO2 forms a core surrounded by ZrO2.