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 exhaust gas treatment system for an internal combustion engine includes an exhaust gas pathway configured to receive exhaust gas from the internal combustion engine, an ammonia source, and a first ammonia injector in fluid communication with the ammonia source. The first ammonia injector is configured to inject ammonia into the exhaust gas pathway at a first rate. The exhaust gas treatment system also includes a first treatment element positioned downstream of the first ammonia injector and a second ammonia injector in fluid communication with the ammonia source and positioned downstream of the first treatment element. The second ammonia injector is configured to inject ammonia into the exhaust gas pathway at a second rate different from the first rate. The exhaust gas treatment system further includes a second treatment element positioned downstream of the second ammonia injector.

The present disclosure describes zoned three way catalyst (TWC) systems including Rhodium-iron overcoat layers and NbZrAl Oxide overcoat layers. Disclosed herein are TWC sample systems that are configured to include a substrate and one or more of a washcoat layer, an impregnation layer, and/or an overcoat layer. In catalyst systems disclosed herein, closed-coupled catalysts include a first catalyst zone with an overcoat layer formed using a slurry that includes an oxide mixture and an Oxygen Storage Material (OSM). In catalyst systems disclosed herein, oxide mixtures include niobium oxide (Nb.sub.2O.sub.5), zirconia, and alumina. Further, catalyst systems disclosed herein include a second catalyst zone with an overcoat layer formed to include a rhodium-iron catalyst. Yet further, catalyst systems disclosed herein include impregnation layers that include one or more of Palladium, Barium, Cerium, Neodymium, and Rhodium.

A gasoline engine having an exhaust system comprises means for trapping particulate matter (PM) from the exhaust gas and a catalyst for catalysing the oxidation of the PM by carbon dioxide and/or water in the exhaust gas, which catalyst comprising a supported alkali metal. The invention further includes a method of combusting PM from a gasoline engine in CO.sub.2 and/or H.sub.2O from the exhaust gas at temperatures in excess of 500 C., which method comprising trapping the PM and contacting it with a catalyst comprising a supported alkali metal.

A wash coat is formed by combining platinum group metals (PGM) and an adhesive with a mixture of catalyst support materials according to the relationship ()RE-CeZrO.sub.2+()CZMLA+(1)RE-Al.sub.2O.sub.3. The RE-CeZrO.sub.2 is a commercial material of rare earth elements stabilized ceria zirconia having a weight ratio () ranging from 0 to about 0.7; CZMLA is a catalyst support material comprising a core support powder coated with a solid solution and has a weight ratio () ranging from about 0.2 to about 1 such that (+)1. RE-Al.sub.2O.sub.3 is rare earth element stabilized alumina having a weight ratio equal to (1). The wash coat exhibits a lower activation temperature compared with traditional wash coat formulations by at least 50 C. This wash coat also requires less RE-CeZrO.sub.2 oxide and/or less PGM in the formulation for use as an emission control catalyst for gasoline and diesel engines.

A catalyzed substrate monolith 12 for use in treating exhaust gas emitted from a lean-burn internal combustion engine, which catalyzed 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.

An oxidation catalyst includes a support including particles of an alkaline earth salt, and first particles including a palladium compound on the support. The oxidation catalyst can also include precious metal group (PMG) metal particles in addition to the first particles intermixed together on the support. A gas permeable polymer that provides a continuous phase can completely encapsulate the particles and the support. The oxidation catalyst may be used as a gas sensor, where the first particles are chemochromic particles.

An exhaust gas purification system includes a previous-stage oxidation catalyst device, an ammonia-based solution feeder, a Diesel Particulate Filter (DPF) device, a turbine of a turbocharger, and a NOx selective reduction catalyst device in the exhaust system of an internal combustion engine in this order from an exhaust port side. The NH.sub.3 production rate is improved, thereby improving the NOx removal rate; the temperature of the DPF device is kept high to increase the time and frequency of continuous regeneration, thus decreasing the frequency of forced regeneration of the DPF device and the amount of discharge of CO.sub.2 produced during the forced regeneration; and also corrosion of the turbine of the turbocharger by SOx is suppressed.

Provided is a catalyst article for simultaneously remediating the nitrogen oxides (NOx), particulate matter, and gaseous hydrocarbons present in diesel engine exhaust streams. The catalyst article has a soot filter coated with a material effective in the Selective Catalytic Reduction (SCR) of NOx by a reductant, e.g., ammonia.

Extruded honeycomb catalyst bodies and methods of manufacturing same. The catalyst body includes a first oxide selected from the group consisting of tungsten oxides, vanadium oxides, and combinations thereof, a second oxide selected from the group consisting of cerium oxides, lanthanum oxides, zirconium oxides, and combinations thereof, and a zeolite.