The invention relates to a catalyst which comprises a carrier substrate, palladium, and a zeolite, the largest channels of which are formed by 10 tetradrically coordinated atoms; to the use of said catalyst as a passive nitrogen oxide adsorber, an exhaust gas system which contains said catalyst and an SCR catalyst, and to a method for purifying the exhaust gas of motor vehicles using said exhaust gas system.

A NO.sub.x absorber catalyst for treating an exhaust gas from a lean burn engine. The NO.sub.x absorber catalyst comprises a molecular sieve catalyst comprising a noble metal and a molecular sieve, wherein the molecular sieve contains the noble metal; an oxygen storage material for protecting the molecular sieve catalyst; and a substrate having an inlet end and an outlet end.

A NO.sub.x adsorber catalyst composition, 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 a support material and one or more platinum group metals disposed on the support material, wherein the support material comprises a NO.sub.x storage enhancer.

An exhaust aftertreatment device includes a housing defining an inlet and an outlet. A plurality of first substrate layers are positioned within the housing in fluid receiving communication with the inlet. The plurality of first substrate layers define a first flow direction, and the plurality of first substrate layers comprise a passive NOx adsorber washcoat. A plurality of second substrate layers are positioned within the housing with the first and second substrate layers being layered in alternating order. The plurality of second substrate layers define a second flow direction perpendicular to the first flow direction, and the plurality of second substrate layers comprise a selective catalytic reduction washcoat. A connecting passage is in fluid receiving communication with the plurality of first substrate layers and in fluid providing communication with the plurality of second substrate layers.

This disclosure is directed to catalyst compositions, catalytic articles for purifying exhaust gas emissions and methods of making and using the same. In particular, the disclosure relates to a catalytic article including a catalytic material on a substrate, wherein the catalytic material has a first layer and a second layer. The first layer provides effective lean NO.sub.x trap functionality and the second layer provides effective three-way conversion of carbon monoxide, hydrocarbons, and nitrogen oxides (NO.sub.x).

Provided are a novel synthesis technique for producing pure phase aluminosilicate zeolite and a catalyst comprising the phase pure zeolite in combination with a metal, and methods of using the same.

The present invention relates to a catalyst which comprises a carrier substrate of length L, which extends between a first end face a and a second end face b, and catalytically active material zones A, B and C of different composition, wherein—material zone A comprises palladium or palladium and platinum with a weight ratio of Pd:Pt>1, and cerium oxide, —material zone B comprises platinum or platinum and palladium with a weight ratio of Pt:Pd>1, and cerium oxide and/or cerium/zirconium mixed oxide, and—material zone C comprises platinum or platinum and palladium with a weight ratio of Pt:Pd>1, and a carrier oxide, and wherein—material zone B is arranged above material zone A, and—material zone C is arranged above material zone B, and, starting from the second end face b of the carrier substrate, extends over a length of up to 60% of the length L. The invention also relates to a catalyst arrangement containing said catalyst.

A nitrogen oxide storage material comprising: Mg.sub.1−yAl.sub.2O.sub.4−y, wherein y is a number satisfying 0≤y≤0.2, a noble metal, an oxide of a metal other than the noble metal, and a barium compound, the noble metal, the oxide, and the barium compound being loaded on Mg.sub.1−yAl.sub.2O.sub.4−y. The metal oxide comprises at least one metal oxide selected from zirconium oxide, praseodymium oxide, niobium oxide, and iron oxide.

Various embodiments include methods for determining the efficiency of an SCR catalytic converter in a system including a nitrogen oxide sensor, and a metering device for a reducing agent arranged in an exhaust-gas duct, and an exhaust recirculation line with a recirculation valve disposed downstream of the SCR catalytic converter and feeding an intake region of the engine. The methods comprise: setting or identifying a quasi-steady-state operating state and an associated recirculation rate; adding a first quantity of reducing agent using the metering device; measuring a resulting first nitrogen oxide value using the sensor; adding a further predefined quantity, different from the first quantity; measuring the resulting nitrogen oxide values using the sensor; and determining the efficiency of the SCR catalytic converter based at least in part on the associated exhaust-gas recirculation rate and the measured nitrogen oxide values.

A honeycomb filter includes a plugged honeycomb structure body which has cell rows arranged along one direction in a cross section of the honeycomb structure body and including a first cell row in which at least the inflow cells are included and in which in the cross section perpendicular to the extending direction of the cells, a through channel area SA occupied by the inflow cells is larger than a through channel area SB occupied by the outflow cells, and a second cell row in which at least the outflow cells are included. A width P1 (mm) of the first cell row, a width P2 (mm) of the second cell row and a curvature radius R (μm) of a curved shape of corner portions of a polygonal shape of each cell satisfy a relation of Equation (1) below: Equation (1): 0.4≤(R/1000)/((P1+P2)/2)×100≤20.