A NO.sub.x adsorber catalyst and its use in an emission treatment system for internal combustion engines, is disclosed. The NO.sub.x adsorber catalyst composition comprises a support material, one or more platinum group metals disposed on the support material, and a NO.sub.x storage material.

A system and method of pre-purification of a feed gas stream is provided that is particularly suitable for pre-purification of a feed air stream in cryogenic air separation unit. The disclosed pre-purification systems and methods are configured to remove substantially all of the hydrogen, carbon monoxide, water, and carbon dioxide impurities from a feed air stream and is particularly suitable for use in a high purity or ultra-high purity nitrogen plant. The pre-purification systems and methods preferably employ two or more separate layers of hopcalite catalyst with the successive layers of the hopcalite separated by a zeolite adsorbent layer that removes water and carbon dioxide produced in the hopcalite layers. Alternatively, the pre-purification systems and methods employ a hopcalite catalyst layer and a noble metal catalyst layer separated by a zeolite adsorbent layer that removes water and carbon dioxide produced in the hopcalite layer.

The invention relates to a particulate filter which comprises a wall flow filter of length L and two catalytically active coatings Y and Z, wherein the wall flow filter comprises channels E and A that extend in parallel between a first and a second end of the wall flow filter and are separated by porous walls which form surfaces OE and OA, respectively, and wherein the channels E are closed at the second end and the channels A are closed at the first end, and the coatings Y and Z have the same oxygen storage components and the same carrier materials for noble metals. The invention is characterised in that the coating Y is located in the channels E on the surfaces OE and the coating Z is located in the channels Aon the surfaces OA.

An exhaust gas purification catalyst provides excellent removal performance of methane, which is chemically stable. Exhaust gas purification catalyst includes a substrate that divides cells through which an exhaust gas flows and a catalyst layer that is provided on a surface of the substrate. The catalyst layer includes a palladium layer containing palladium that extends from a first end part which is an end part on the side into which an exhaust gas in the cells flows to a second end part which is an end part on the side from which an exhaust gas flows out, a platinum layer containing platinum that extends from the second end part to the first end part, and a rhodium layer containing rhodium that is laminated with both the palladium layer and the platinum layer.

An exhaust gas purification catalyst device having a substrate, a first catalyst coating layer on the substrate, and a second catalyst coating layer on the first catalyst coating layer. The first catalyst coating layer includes inorganic oxide particles, palladium carried on the inorganic oxide particles, and a barium compound. The second catalyst coating layer includes alumina particles and rhodium carried by the alumina particles. The ratio (M.sub.Ba/M.sub.Rh) between the mass (M.sub.Ba) of barium in the first catalyst coating layer and the mass (M.sub.Rh) of rhodium in the second catalyst coating layer is 5.0-60.0 inclusive.

A filter for removing gaseous components from a gas stream. The filter includes a frame with outer members and support members mounted thereto. The filter includes a prefilter layer disposed upstream in the frame and a reactive layer disposed in the frame downstream from the prefilter layer. The reactive layer includes particulate that removes gaseous components from the gas stream. A containment layer is disposed in the frame downstream from the reactive layer. The frame supports the layers from the airstream flowing through the filter. This configuration reduces the quantity of reactive material required and permits significant variability in the reactive materials used on the reactive layers because the different reactive layers have little to no effect on one another.

An exhaust gas purification catalyst device has catalyst coating layers, which extend from the upstream side to the downstream side of the exhaust gas flow. The catalyst coating layers each have at least three zones present in order from the upstream side to the downstream side of the exhaust gas flow, and each of these at least three zones is an oxidation catalyst zone or a reduction catalyst zone. In the uppermost layer of an oxidation catalyst zone, the total number of atoms of platinum and palladium is greater than the number of atoms of rhodium; in the upper most layer of a reduction catalyst zone, the number of atoms of rhodium is greater than the total number of atoms of platinum and palladium. The oxidation catalyst zones and the reduction catalyst zones alternate at least twice in the exhaust gas flow direction.

The invention relates to a particulate filter which comprises a wall flow filter of length L and two different catalytically active coatings Y and Z, wherein the wall flow filter comprises channels E and A that extend in parallel between a first and a second end of the wall flow filter and are separated by porous walls which form surfaces OE and OA, respectively, and the channels E are closed at the second end and the channels A are closed at the first end. The invention is characterised in that the coating Y is located in the channels E on the surfaces OE and the coating Z is located in the channels A on the surfaces OA.

Certain selective catalytic reduction (SCR) articles, systems and methods provide for high NOx conversion while at the same time low N.sub.2O formation. The articles, systems and methods are suitable for instance for the treatment of exhaust gas of diesel engines. Certain articles have zoned coatings disposed thereon, for example, a zoned coating comprising an upstream zone comprising a coating layer comprising a steam-activated iron-containing molecular sieve and a downstream zone comprising a coating layer comprising a high copper-containing molecular sieve.

It is an object to provide a catalyst that can effectively purify exhaust gas, in particular, carbon monoxide (CO) in exhaust gas, emitted from a diesel engine, a production method therefor, and an exhaust gas purification method using the same. A diesel engine exhaust gas purification catalyst for purifying exhaust gas emitted from a diesel engine of the present invention comprises a precious metal and alumina and/or zeolite supported on a three-dimensional structure, and has peaks for not less than three different pore sizes in a pore size distribution measured by the mercury intrusion method, wherein one of the peaks is a peak 2 at a pore size of not less than 0.3 μm and less than 1.0 μm, and the pore volume of the peak 2 being greater than 3.1% of the total pore volume.