The present invention provides a honeycomb catalytic converter including: a honeycomb structured body in which multiple through-holes are arranged longitudinally in parallel with one another with a partition wall therebetween; and a noble metal supported on the honeycomb structured body, wherein the honeycomb structured body contains a ceria-zirconia composite oxide and alumina, and cerium on a surface of each partition wall has a lower concentration than cerium in a central portion of the partition wall in a thickness direction.

An object of the present disclosure is to provide an NO.sub.x storage material having sufficient NO.sub.x storage capacity even in a low temperature region and a production method thereof. An NO.sub.x storage material including a composite oxide of silver and gallium. The composite oxide of silver and gallium is preferably a delafossite-type composite oxide. The composite oxide is produced by dissolving a silver salt and a gallium salt in a solvent and baking the solution, wherein the molar ratio of silver:gallium is preferably from 2:8 to 7:3.

Herein disclosed are compositions for passive NOx adsorption and oxidation that include at least a manganese-based oxide and one or more promoter materials and methods for making and using said compositions. The promotor materials may include a rare earth, transition, or main group metal. The compositions may be used in NOx emission control system and adsorbs NOx compounds at low temperatures and then release NOx at higher temperatures, where the NOx can be oxidized, without the hybridized MnOX composition breaking down. The compositions are capable of maintaining a sufficiently large surface area at high temperatures found in the emissions gas streams of internal combustion engines necessary for the complete elimination of NOx.

A method of treating an exhaust gas from an internal combustion engine comprising contacting the exhaust gas with a lean NO.sub.x trap catalyst is disclosed. The lean NO.sub.x trap catalyst comprises a first layer and a second layer.

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.

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.