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.

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.

Provided is an exhaust gas purification catalyst in which the performance of a catalyst metal can be brought out properly, the purification catalyst boasting excellent purification performance during warm-up of an internal combustion engine. The exhaust gas purification catalyst 10 is provided with a substrate 1 and a catalyst layer. A leading end section 1a positioned upstream in the direction of exhaust gas flow (arrow) has a portion in which the flow rate of exhaust gas is relatively high and a portion in which the flow rate of exhaust gas is relatively low during warm-up of the internal combustion engine. The catalyst, layer in the portion of relatively high flow rate of exhaust gas has a high density section 6 in which a noble metal, is supported at relatively high density. The high density section 6 is formed to be shorter than the total length of the exhaust gas purification catalyst 10 from the leading end section 1a in the direction of exhaust gas flow.

A catalytic converter with excellent OSC performance and No.sub.x purification performance. The catalytic converter includes a substrate with a cell structure and a catalyst layer formed on a cell wall surface of the substrate. The catalyst layer has a catalyst layer arranged on the upstream side and a catalyst layer arranged on the downstream side in an exhaust gas flow direction on the substrate. The catalyst layer on the upstream side includes a support containing an Al.sub.2O.sub.3—CeO.sub.2—ZrO.sub.2 ternary composite oxide (ACZ material) and an Al.sub.2O.sub.3—ZrO.sub.2 binary composite oxide (AZ material), and at least Rh that is a noble metal catalyst carried on the support, and the catalyst layer on the downstream side includes a support and Pd or Pt that is a noble metal catalyst carried on the support. In the support in the catalyst layer on the upstream side, the mass proportion of ACZ material/(ACZ material+AZ material) is in the range of 0.33 to 0.5, and greater than or equal to 75% mass Rh is carried on the Al.sub.2O.sub.3—ZrO.sub.2 binary composite oxide of the support.

An exhaust gas-purifying catalyst of the present invention comprises a substrate, and one or more catalytic layers provided on the substrate, wherein at least one of the catalytic layers (i) contains a precious metal, alumina, and an acidic oxide element, (ii) has a correlation coefficient ρ.sub.Al,AE of 0.70 or more, and (iii) has a correlation coefficient ρ.sub.PM,AE of 0.70 or more.

This oxidation catalyst for diesel engines is divided into an upstream-side catalyst layer and a downstream-side inner catalyst layer in the flow direction of the exhaust gas, and a downstream-side outer catalyst layer is additionally formed so as to cover the surface of the downstream-side inner catalyst layer. The upstream-side catalyst layer and the downstream-side inner catalyst layer contain Pd, and the downstream-side outer catalyst layer contains Pt. The amounts of Pt and Pd contained in the upstream-side catalyst layer and the amounts of Pt and Pd contained in the downstream-side inner catalyst layer are constantly set to certain values, while the amount of Pt contained in the downstream-side outer catalyst layer is set to a value which enables the oxidation efficiency to be at a predetermined value or higher.

An exhaust gas treatment system for an internal combustion engine includes an exhaust gas pathway configured to receive exhaust gas from the internal combustion engine, a first treatment element positioned within the exhaust gas pathway, a first injector configured to introduce a first reductant into the exhaust gas pathway upstream of the first treatment element, a second injector configured to introduce a second reductant into the exhaust gas pathway downstream of the first treatment element, a second treatment element positioned within the exhaust gas pathway downstream of the second injector, the second treatment element including a SCR element, and a controller configured to periodically initiate a desulfuring regeneration cycle by increasing a concentration of hydrocarbons in the exhaust gas and increasing the flow of the first reductant through the first injector to oxidize sulfur contamination in the first treatment element at temperatures between 400 and 500 degrees Celsius.

A catalyst converter includes: a substrate (1) having a cell structure formed of a center area (1A) having the highest cell density, a peripheral area (1C) having the lowest cell density, and an intermediate area (1B) having the cell density between that of the center area and that of the peripheral area; a first catalyst layer formed in the center area (1A); a second catalyst layer formed in the intermediate area (1B); and a third catalyst layer formed in the peripheral area (1C). A length in a longitudinal direction of the second catalyst layer is longer than that of the first catalyst layer. A length in the longitudinal direction of the third catalyst layer is longer than that of the second catalyst layer. A ratio of the length in the longitudinal direction of the first catalyst layer to the length of the substrate is 65% or more.

The invention relates to a particle filter (1) for an exhaust gas system (2), and to a method for producing a particle filter. The particle filter (1) comprises a plurality of flow channels (5), which extend from a first end face (6) towards a second end face (7) and which are separated from one another by porous channel walls (8). On the end faces (6, 7), the flow channels (5) each have mutual closing means (9) such that an exhaust gas (10) enters a flow channel (5) that is open on the first end face (6), flows through the channel wall (8), and escapes from the particle filter (1) by way of an adjacent flow channel (5) that is open on the second end face (7). In a direction of flow (11), the channel wall (8) has, in succession, the following layers: a particle filter layer (13); an intermediate layer (14) comprising a first SCR coating (15) having a first catalytic activity (16); a second SCR coating (18) having a second catalytic activity (19), wherein the second catalytic activity (19) is different from the first catalytic activity (16).