Abstract: A sorbent composition is provided which can be used in the desulfurization of a hydrocarbon-containing fluid such as cracked gasoline or diesel fuel. The sorbent composition contains a support component and a promoter component with the promoter component being present as a skin on the support component. Such sorbent composition is prepared by a process of impregnating a support component with a promoter component, wherein the promoter component has been melted under a melting condition, followed by drying, calcining, and reducing to thereby provide the sorbent composition.

Abstract: Oxidation catalysts useful in the oxidation to CO2 and H2O of volatile organic compounds such as hydrocarbons comprising mixed oxides of copper, manganese and one or more rare-earth metals, wherein the metals can assume multiple valency states, having a percentage composition by weight, expressed as CuO, MnO and rare-earth oxides, in which the metal has the minimum value of 8-50%, 10-75% and 2-15%. The oxides are supported on inert porous inorganic oxides.

Abstract: A process for preparing 1,2-dichloroethane by reacting about 2 mols of ethylene, about 4 mols of hydrogen chloride and about 1 mol of oxygen in the presence of a fixed bed of supported catalyst based on copper(II) chloride in only one reaction zone at a pressure of from 2 to 10 bar and at from 220 to 280° C.

Abstract: A method of dispersing nanosized catalyst particles on the surface of larger catalyst carrier particles is disclosed. The coating process is done dry and yields high effective surface area of nanosized catalyst particles coated on the surface of catalyst carrier particles. In this process, nanosized catalyst particles and catalyst carriers are mechanically mixed in a high velocity and impact force environment to which catalyst particles are embedded, or filmed, on the surface of catalyst carrier particles without using water or any other additional chemicals. The catalyst composite structure produced comprises better coating uniformity of the catalyst particle on its catalyst carrier. The catalyst particle/catalyst carrier composite produced can be applied to a support structure, such as a monolith as readily used in automotive or other applications.

Abstract: A material composed of ultrafine particles, comprising at least a metal element M having catalytic properties and at least a metal element M′ having a standard oxidation potential less than that of M, part at least of M′ atoms being in oxidized form, the average size of the particles being less than 50 nm, at least 80% in number of the particles having an average size less than 10 nm. One particle of the material is constituted by at least a metal element M with oxidation level 0, or by at least a metal element M′ in oxidized form, or by at least a metal element M′ with oxidation level 0, or by the combination of at least two species selected from the three previous species. The material is useful as a catalyst for hydrogenation or coupling reactions.

Abstract: A catalyst and process for converting carbon dioxide into oxygenates. The catalyst comprises copper, zinc, aluminum, gallium, and a solid acid.

Abstract: A mixed metal oxide Mo—V—Ga—Pd—Nb—X catalytic system, where X is selected from La, Te, and Zn, provides the oxidation of C2-C8 hydrocarbons to corresponding acids with a molecular oxygen-containing gas.

Abstract: A method of treating a catalyst support comprises introducing onto and/or into an untreated catalyst support which is partially soluble in an aqueous acid solution and/or a neutral aqueous solution, Si, Zr, Cu, Zn, Mn, Ba, Co, Ni and/or La as a modifying component. The modifying component is capable, when present in and/or on the catalyst support, of suppressing the solubility of the catalyst support in the aqueous acid solution and/or the neutral aqueous solution. A protected modified catalyst support which is less soluble or more inert in the aqueous acid solution and/or the neutral aqueous solution, than the untreated catalyst support, is thus formed. A method of forming a catalyst from the modified catalyst support is also provided.

Abstract: A low temperature metal promoted copper/zinc/aluminum water gas shift catalyst is described. The catalyst is formed from a precursor, wherein the precursor includes aluminum in the form of hydrotalcite and aluminum separate from the hydrotalcite. A method of making the catalyst and a process for using the catalyst are also described.

Abstract: Novel sorbent systems for the desulfurization of cracked-gasoline and diesel fuels are provided which are comprised of a bimetallic promotor on a particulate support such as that formed of zinc oxide and an inorganic or organic carrier. Such bimetallic promotors are formed of at least two metals of the group consisting of nickel, cobalt, iron, manganese, copper, zinc, molybdenum, tungsten, silver, tin, antimony and vanadium with the valence of same being reduced, preferably to zero. Processes for the production of such sorbents are provided wherein the sorbent is prepared from impregnated particulate supports or admixed to the support composite prior to particulation, drying, and calcination. Further disclosed is the use of such novel sorbents in the desulfurization of cracked-gasoline and diesel fuels whereby there is achieved not only removal of sulfur but also an increase in the olefin retention in the desulfurized product.

Abstract: A method by which a highly active catalyst for the steam reforming of methanol is efficiently produced by a simple process. The catalyst is produced from alloy fine particles obtained by first grinding an Al alloy containing quasi-crystals consisting of aluminum, copper and at least one metal atom selected from Fe, Ru and Os, and then leaching the ground Al alloy.

Abstract: Fixed-bed Raney-type catalysts are made from metal alloy fibers and/or flakes previously fabricated according to the crucible metal extraction method and then tablated, pressed in mats and/or located into a cartridge. The catalysts are used for the hydrogenation, dehydrogenation, isomerization, reductive alkylation, reductive amination, and/or hydration of organic compounds.

Abstract: An object of the present invention is to provide a methanol reforming catalyst, which promotes both the steam reforming reaction and the partial oxidation reaction simultaneously so as to achieve a high methanol conversion rate and suppress the carbon monoxide formation. The present invention provides a methanol reforming catalyst having an oxide containing a Cu, Zn and Al.

Abstract: Acetylenic compounds in olefin streams such as mixed 1,3-butadiene were selectively hydrogenated over the supported copper catalysts on highly porous supports such as alumina, silica, etc. The preferred supports have the average pore diameter larger than about 200 Å, no micro pores, total pore volume larger than about 0.65 cc/g, and preferably less than about 230 m2/g BET surface area. The copper catalysts were preferably promoted with the Group VIII metal such as palladium to improve low activity of copper catalyst. The product stream typically contains less than 20 ppm total alkynes. Also the copper catalysts and the palladium promoted copper catalysts may be modified with zinc oxide to improve the performance of the catalysts. The reactor was loaded with two or more copper catalysts promoted with different levels of palladium.

Abstract: Monolithic metallic catalyst substrates offering improved heat conductivity are provided from metal powder extrusion batches of copper, tin, zinc, aluminum, iron, silver, nickel, and mixtures and alloys thereof by extrusion through a honeycomb extrusion die followed by drying and firing in a two stage firing process to oxidize organic extrusion batch components, remove residual oxides from the porous wall structure, and consolidate the metal powders to strong, integral honeycomb support structures.

Abstract: A microcrystalline boehmite containing additive in a homogeneously dispersed state. Suitable additives are compounds containing elements selected from the group consisting of alkaline earth metals, alkaline metals, rare earth metals, transition metals, actinides, silicon, gallium, boron, titanium, and phosphorus. The microcrystalline boehmite according to the invention may be prepared in several ways. In general, a microcrystalline boehmite precursor and an additive are converted to a microcrystalline boehmite containing the additive in a homogeneously dispersed state. The additive does not contain zirconia or magnesia.

Abstract: A non-chrome, copper-containing catalyst, Cu—Al—O and method of preparing the same are provided wherein the Cu—Al—O catalyst is prepared by the co-precipitation of copper nitrate (Cu(NO3)2) and sodium aluminate (Na2Al2O4) solutions using sodium carbonate (Na2CO3) as a precipitant. The precipitate is filtered, washed to removed excess sodium, and dried. The dried product, to be used in a powder form, is calcined at a preferred temperature of approximately 700° to 900° C. for approximately 1 to 4 hours. The dry powder, to be tableted or extruded, is calcined at a temperature of approximately 400° to 700° C. The activity of the Cu—Al—O catalyst can be promoted in hydrogenolysis applications by the addition of various agents. The Cu—Al—O catalyst can be employed in applications in place of Cu/Cr, or other copper based catalysts.

Abstract: Composite of at least two metal oxides in the form of Primary Particles and a support having a particle size greater than the Primary Particles used in the formation of a catalyst composition for the treatment of a pollutant containing gas.

Abstract: The spinel monolith catalyst is obtainable by a) preparing or coating a molding, especially a monolith, with an at least surfacial active composition comprising a spinel of the general formula (I) AxB(1−x)E2O4  (I)  where A is Cu, of which up to half may be replaced by Co, Fe, Ni, Mn or Cr, B is at least one element selected from the group consisting of Zn, Mg, Ca, Zr, Ce, Sn, Ti, V, Mo and W, E is Al, of which up to half may be replaced by Fe2O3, Cr2O3, Ga2O3, La2O3 or mixtures thereof, x is from 0 to 1, preferably 0 to 0.9, b) impregnating the monolith with a solution of at least one compound of elements of transition group 5 of the periodic table or adding these elements in step a) in the form of their oxides or salts, c) drying and optionally calcining.

Abstract: Shaped catalysts for heterogeneously catalyzed reactions are in the form of hollow cylinders or annular tablets whose end faces are rounded both to the outer edge and to the edge of the central hole, i.e. have no right-angled edges.

Abstract: A novel catalyst and the use thereof in a reforming process is disclosed. The catalyst comprises a refractory inorganic oxide, platinum-group metal, Group IVA(IUPAC 14) metal, indium and lanthanide-series metal. Utilization of this catalyst in the conversion of hydrocarbons, especially in reforming, results in significantly improved selectivity to the desired gasoline or aromatics product.

Abstract: A catalyst for oxidation of ammonia is of the general formula (AxByO3z)k (MEmOn)f, wherein: A is a cation of Ca, Sr, Ba, Mg, Be, La or mixtures thereof, B is cations of Mn, Fe, Ni, Co, Cr, Cu, V or mixtures thereof, x=0-2, y=1-2, z=0.8-1.7; MemOn is an aluminum oxide and/or oxide of silicon zirconium, chromium, aluminosilicates, oxides of rare earth elements (REE) or mixtures thereof, m=1-3, n=1-2, k and f are % by weight, with the ratio f/k=0.01-1. The catalyst may be granules of different configuration, including blocks of honeycomb structure. The catalyst is thermally stable, resistant to thermal shocks. There is no water runoff.

Abstract: Catalysts containing passivated copper and zinc oxide and/or alumina are prepared by

Abstract: A non-chrome, copper-containing catalyst, Cu—Al—O and method of preparing the same are provided wherein the Cu—Al—O catalyst is prepared by the co-precipitation of copper nitrate (Cu(NO3)2) and sodium aluminate (Na2Al2O4) solutions using sodium carbonate (Na2CO3) as a precipitant. the precipitate is filtered, washed to remove excess sodium, and dried. The dried product, to be used in a powder form, is calcined at a preferred temperature of approximately 700 to 900° C. for approximately 1 to 4 hours. The dry powder, to be tableted or extruded, is calcined at a temperature of approximately 400 to 700° C. The activity of the Cu—Al—O catalyst can be promoted in hydrogenolysis applications by the addition of various agents. The Cu—Al—O catalyst can be employed in applications in place of Cu/Cr, or other copper-based catalysts.

Abstract: A process for the catalytic hydrogenation of a carbonyl compound or of a mixture of two or more carbonyl compounds in the presence of a catalyst which comprises an inorganic support containing TiO2, and as active component copper or a mixture of copper and at least one of the metals selected from the group of zinc, aluminum, cerium, a noble metal and a group VIII metal, wherein the copper surface area does not exceed 10 m2/g.

Abstract: An exhaust gas purification device includes a porous body of catalytic material of the general formula AaBbO4 disposed in an exhaust gas stream of an engine. The porous body of catalytic material has a characteristic response temperature above which it is catalytically active to reduce pollutants in the presence of a reducing agent. The porous body stores at least 20% by volume hydrocarbons at temperatures below the response temperature. A represent at least one element selected from Mg, Ca, Mn, Fe, Ni, Co, Cu, Zn, Sn, Ti and A+B is less than 3, A is greater than 0 and B greater than 0.

Abstract: A process for manufacturing a catalyst body for generating hydrogen having at least one thin, large-surface catalyst layer, through which the reaction mixture can be passed includes steps of pressing a copper powder (particularly dendritic copper) to form a thin and highly compressed layer which forms a formed body, sintering, the formed body in a reducing atmosphere so that a net-type carrier structure made of copper is formed, and activating a surface layer of the formed body.

Abstract: A catalyst composition is provided which can be used for hydrogenating a highly unsaturated hydrocarbon such as an alkyne or a diolefin. The catalyst composition contains palladium, a catalyst component of either silver or an alkali metal compound, or both silver and an alkali metal compound, and a metal aluminate catalyst support. Such metal aluminate catalyst support is prepared by a process of incorporating alumina with a metal component, preferably impregnating alumina with a melted metal component, to thereby provide a metal-incorporated alumina followed by drying and high temperature calcining to thereby provide a metal aluminate catalyst support. The catalyst composition disclosed can be used for hydrogenating a highly unsaturated hydrocarbon to a less unsaturated hydrocarbon. The process involves contacting a highly unsaturated hydrocarbon with a catalyst composition in the presence of hydrogen under a hydrogenation condition sufficient to effect a hydrogenation of the highly unsaturated hydrocarbon.

Abstract: A storage catalyst includes (1) a component that has a catalytic reducing action for nitrogen oxides at least in the presence of hydrocarbons, and (2) a component that stores NOx at least at temperatures of below 100° C. The catalytically active component is of the general chemical formula AaBbO4, where A is one or more divalent metals and B is one or more trivalent metals, and where a+b≦3 and a, b>0. The reaction enthalpy or the chemical activity between the catalytically active component and the NOx-storing component is low at least up to temperatures of 600° C.

Abstract: The present invention relates to non-noble metal combustion catalyst for carbon monoxide comprising Cu—Al/Ce—Al complex oxides and aluminum oxide support. The catalysts comprise Ce—Al complex oxide and Cu—Al complex oxide successively loaded on the aluminum oxide support, wherein the loading weight ratio is 0.02-0.10 for Ce—Al—O/Al2O3 and 0.05-0.15 for Cu—Al—O/Al2O3, and the Cu—Al complex oxide is dispersed in cluster form on the surface of the aluminum oxide support pre-covered with high dispersed nanoparticles of the Ce—Al complex oxide. Furthermore, the present invention relates to a process for preparing the catalysts and their use as combustion promoter with high catalytic activity, high hydrothermal stability and ability of reducing NOx exhaust in the fluid catalytic cracking (FCC) process of petroleum refining.

Abstract: The invention relates to a process for producing compositions containing a biocidal compound or adsorbent and/or catalyst compound and the compositions thereof. The invention also relates to a method for reducing or eliminating the amount of a bioactive agent or contaminant from an environment by contacting the environment with the composition of for a sufficient time to reduce or eliminate the amount of the bioactive agent or contaminant in the environment.

Abstract: The present invention provides a method of producing a CuZnAlZr oxide catalyst consisting of reacting an aqueous NaOH solution and aqueous NACO3 solution with a mixture of aqueous solutions of each nitrate of Cu, Zn, Al, and Zr, producing a precipitate by coprecipitation, aging, filtering, washing and drying this precipitate to prepare a catalyst precursor consisting of a CuZnAlZr layered double hydroxide, and then obtaining a CuZnAlZr oxide by calcining this precursor in an air ambient atmosphere, a CuZnAlZr oxide catalyst, a CuZnZrCe oxide catalyst, a CoCuZnAl oxide catalyst for producing hydrogen by oxidative steam reforming of methanol, and methods of producing hydrogen gas consisting of converting methanol to hydrogen gas by oxidative steam reforming in the presence of air and steam using these oxide catalysts.

Abstract: Compositions comprising a component containing (i) an acidic oxide support, (ii) an alkali metal and/or alkaline earth metal or mixtures thereof, (iii) a transition metal oxide having oxygen storage capability, and (iv) a transition metal selected from Groups Ib and/or IIb of the Periodic Table provide NOx control performance in FCC processes. The acidic oxide support preferably contains silica alumina. Ceria is the preferred oxygen storage oxide. Cu and Ag are preferred Group I/IIb transition metals. The compositions are especially useful in the cracking of hydrocarbon feedstocks having above average nitrogen content.

Abstract: A catalyst comprising at least one metal of the 10th group of the Periodic Table of the Elements and at least one metal of the 11th group of the Periodic Table of the Elements on an aluminum oxide support, wherein the metal or metals of the 10th group is or are essentially concentrated in an outer layer close to the surface of the catalyst particle, the metal or metals of the 11th group is or are distributed essentially uniformly over the volume of the catalyst particle and the weight ratio of the metal or metals of the 11th group to the metal or metals of the 10th group is not more than 1.95.

Abstract: This invention relates to a process for producing an enhanced adsorbent particle comprising contacting a non-amorphous, non-ceramic, crystalline, porous, calcined, aluminum oxide particle that was produced by calcining at a particle temperature of from 300° C. to 700° C., with an acid for a sufficient time to increase the adsorbent properties of the particle. A process for producing an enhanced adsorbent particle comprising contacting a non-ceramic, porous, oxide adsorbent particle with an acid for a sufficient time to increase the adsorbent properties of the particle is also disclosed. Particles made by the process of the instant invention and particle uses, such as remediation of waste streams, are also provided. The invention also relates to a method for producing an adsorbent and/or catalyst and binder system. The invention also relates to particles made by the process, binders, and methods for remediating contaminants in a stream.

Abstract: Catalysts for heterogeneously catalyzed reactions which comprise active components and a catalyst support comprising amounts of &dgr;-Al2O3 which can be detected by X-ray diffractometry, in particular for the oxychlorination of ethylene to 1,2-dichloroethane.

Abstract: The invention relates to a method for producing an adsorbent and/or catalyst and binder system comprising I) mixing components comprising (a) a binder comprising a colloidal metal oxide or colloidal metalloid oxide, (b) an oxide adsorbent and/or catalyst particle, and (c) an acid, (ii) removing a sufficient amount of water from the mixture to cross-link components a and b to form an adsorbent and/or catalyst and binder system. The invention also relates to particles made by the process, binders, and methods for remediating contaminants in a stream.

Abstract: The present invention provides a method by which a highly active catalyst for the steam reforming of methanol is efficiently produced by a simple process. The catalyst is produced from alloy fine particles obtained by first grinding an Al alloy containing quasi-crystals consisting of aluminum, copper and at least one metal atom selected from Fe, Ru and Os, and then leaching the ground Al alloy.

Abstract: Stable highly active supported copper based catalysts are comprised of copper oxide or elemental copper crystallites supported on mechanically stable aluminum oxide and are characterized by high surface area, small copper crystallite size, and high metal loading. The average crystallite size of the copper compound is from about 20 to about 300 Å, the copper loading is from about 10 to about 35 weight percent, the average particle diameter is from about 0.1 mm to about 10 mm, and the total surface area is from about 20 to about 400 square meters per gram. The catalysts are useful for hydration of nitriles to amides, especially hydration of acrylonitrile to acrylamide. The catalysts are distinguished by high mechanical stability, extended lifetime, and excellent resistance to hydration and copper leaching.

Abstract: Shaped catalysts for heterogeneously catalyzed reactions are in the form of hollow cylinders or annular tablets whose end faces are rounded both to the outer edge and to the edge of the central hole, i.e. have no right-angled edges.

Abstract: Exhaust emission control catalysts capable of efficiently removing nitrogen oxide in exhaust containing a large amount of oxygen emitted from a diesel engine and the like and reducing the generation of particulate matter in the exhaust under high temperature conditions, and a method for controlling the emission of exhaust using the exhaust emission control catalysts. The exhaust emission control catalysts contain copper, praseodymium, and yttrium. The method for controlling the emission of exhaust purifies exhaust containing hydrocarbon and nitrogen oxide in a mole ratio (hydrocarbon/nitrogen oxide) within a range of 0.5 to 30 by bringing the exhaust into contact with the exhaust emission control catalysts. It is possible to efficiently remove nitrogen oxide in the exhaust by reduction while suppressing the oxidation of sulfur dioxide in the exhaust.

Abstract: A process for catalytically isomerizing olefins, particularly for isomerizing alkenyl bridged ring compounds to the corresponding alkylidene bridged ring compounds. The catalyst is prepared by forming a dispersion of a metallic alkali metal on a support with simultaneous exposure to oxygen.

Abstract: Compositions comprising a component containing (i) an acidic oxide support, (ii) an alkali metal and/or alkaline earth metal or mixtures thereof, (iii) a transition metal oxide having oxygen storage capability, and (iv) a transition metal selected from Groups Ib and/or IIb of the Periodic Table provide NOx control performance in FCC processes. The acidic oxide support preferably contains silica alumina. Ceria is the preferred oxygen storage oxide. Cu and Ag are preferred Group I/IIb transition metals. The compositions are especially useful in the cracking of hydrocarbon feedstocks having above average nitrogen content.

Abstract: A system for treating the exhaust of an industrial process or combustion source to capture gaseous sulfur compounds which includes contacting the exhaust containing gaseous sulfur compounds with a system of: (1) a structured support coated with for example a monolith (2) a ceramic oxide containing for example TiO2 (3) a precious metal component for example Pt and optionally (4) a modifier such as Cu. The system captures the gaseous sulfur compounds. Gaseous sulfur compounds are then driven off in higher concentrations in a separate isolated lower flow stream in higher concentrations which are easier to process to less noxious or useful sulfur materials, and the catalyst/sorber regenerated. The system also removes carbon dioxide by the oxidation of the carbon monoxide to carbon dioxide.

Abstract: A completely metallic catalyst for the oxidation of mixtures in the gaseous phase which contain carbon monoxide, hydrocarbons and/or soot, has a surface doped with a metallic element and is subjected to a second thermal treatment in an oxygen-containing atmosphere.

Abstract: Novel sorbent systems for the desulfurization of cracked-gasoline are provided which are comprised of a bimetallic promotor on a particulate support such as that formed of zinc oxide and an inorganic or organic carrier. Such bimetallic promoters are formed of at least two metals of the group consisting of nickel, cobalt, iron, manganese, copper, zinc, molybdenum, tungsten, silver, tin, antimony and vanadium with the valence of same being reduced, preferably to zero. Processes for the production of such sorbents are provided wherein the sorbent is prepared from impregnated particulate supports or admixed to the support composite prior to particulation, drying, and calcination. Further disclosed is the use of such novel sorbents in the desulfurization of cracked-gasoline whereby there is achieved not only removal of sulfur but also an increase in the olefin retention in the desulfurized product. Such sorbents can also be utilized for the treatment of other sulfur-containing streams such as diesel fuels.

Abstract: This invention relates to the process of preparing from carbon dioxide a mixture of dimethyl ether and methanol which are useful as clean fuel or raw materials in the chemical industry. More particularly, this invention relates to the process of preparing dimethyl ether and methanol in high yield without by-products such as hydrocarbons by means of chemical conversion of carbon dioxide, which is a major pollutant of the global environment, in the presence of a mixture of catalysts comprising Cu/ZnO-based catalyst and Y-type zeolite catalyst having a strong acidity with the pKa value of −6.0-−3.0.

Abstract: A highly durable exhaust emission control device which is provided in a container disposed in an intermediate portion of an exhaust system, wherein the exhaust emission control device comprises (1) a heat-resistant porous body having communicating pores, (2) a mixture of copper oxide and aluminum oxide supported on the surface of the porous body, and (3) platinum supported on the surface and an inner portion of the mixture, the grain size of the copper oxide being from 0.1 &mgr;m to 50 &mgr;m. The exhaust emission control device is manufactured by preparing the heat-resistant porous body; (2) applying to the porous body a slurry of a mixture of copper oxide and aluminum oxide and/or compounds convertible into these oxides by firing, and baking the mixture and/or compounds; and (3) applying a water-soluble platinum compound to the porous body, and baking the platinum compound. The platinum compound may be applied with the oxide mixture and/or the compounds of copper and aluminum to the porous body.

Abstract: An exhaust gas purifying catalyst for use in an oxygen surplus atmosphere, includes a brown millerite composite oxide for directly decomposing and absorbing nitrogen oxide (NOx), and a noble metal-series reducing catalyst disposed on the surface of said brown millerite composite oxide. The brown millerite composite oxide is represented by one of the following formulae: A3-aBaC4-bDbO9, A2-aBaC2-bDbO5, and A1-aBaC2-bDbO4 where A and B are elements selected from the group consisting of Ba, Ca, Sr, Mg and Ce, C and D are elements selected from the group consisting of Y, Dy, Zn, Ti, Mn, Fe, Co, Ni, Cu, Sn, Zr and Nd, a is within the range 0≦a<1, and b is within the range 0≦b<2.

Abstract: The invention is a sol-gel processed metal-aluminum based oxide material useful as a catalyst including a NOx trapping catalyst. It is made from alkoxides comprising heterometallic alkoxides. The metal is transition metal, one or both of alkali metal and alkaline earth metal, and optionally also a lanthanide. Then invention is also a method of treating lean-burn internal combustion engine exhaust gas with this material, without any precious metal included with the material, in the exhaust gas system. The method comprises locating the NOx trap in the system where the NOx trap absorbs nitrogen oxides during lean cycle operation and desorbs the nitrogen oxides when the concentration of the oxygen in the exhaust gas is lowered as during a rich or stoichiometric cycle.