Abstract: A bifunctional oxygen electrocatalyst, a preparation method and use thereof are disclosed. The bifunctional oxygen electrocatalyst is represented by A1-x-yBxCyO2, wherein element A is one selected from the group consisting of Pt, Ir, Ru, and Pd, and each of element B and element C is selected from the group consisting of Mo, Mn, Fe, Co, Ni, Cu and Zn; the bifunctional oxygen electrocatalyst is a three-dimensional porous foam sheet catalyst; optionally, the element B is the same as the element.

Abstract: A method of manufacturing a catalyst article, the method comprising: providing a complex of a polyphenol and a PGM, the polyphenol comprising an ester functional group, the PGM comprising palladium; providing a support material; applying the complex to the support material to form a loaded support material; disposing the loaded support material on a substrate; and heating the loaded support material to form nanoparticles of the PGM on the support material.

Abstract: Novel doped oxide and mixed-oxide materials having a metal homogenously dispersed in the form of isolated metal ions throughout the oxide lattice and methods for making the same.

Abstract: When the porous ceramic structure contains Co together with Fe or Mn, the Co content is higher than or equal to 0.1 mass % and lower than or equal to 3.0 mass % in terms of Co3O4, and when the porous ceramic structure contains Co without containing Fe and Mn, the Co content is higher than or equal to 0.2 mass % and lower than or equal to 6.0 mass % in terms of Co3O4. The Ce content is higher than or equal to 0.1 mass % and lower than or equal to 10 mass % in terms of CeO2. The Fe/Mn/Co ratio is higher than or equal to 0.8 and lower than or equal to 9.5. The porous ceramic structure contains more than or equal to 0.03 percent and less than or equal to 2.5 percent by mass of Zn in terms of ZnO.

Abstract: Methods and compositions related to a selective catalytic reduction catalyst comprising iron and vanadium, wherein the vanadium is present as (1) one or more vanadium oxides, and (2) metal vanadate of the form FexMyVO4 where x=0.2 to 1 and y=1?x, and where M comprises one or more non-Fe metals when y>0.

Abstract: The present disclosure is directed to compositions comprising Ce-containing mixed oxides, especially those having a stoichiometry of LnyCexMwOz; where 0.15?x?0.5, y?0.25, w=(1?x?y)?0.5, and z=(2x+2w+1.5y); M is Zr, Hf, Ti, Sn or Ge or a combination thereof; Ln is Y and/or one or more rare earth metals, exclusive of Ce, and the uses of these compositions. These compositions are characterized by the even distribution of the Ce in the lattice of the mixed oxide.

Abstract: Provided is, for example, an exhaust gas-purifying three-way catalyst which is small in the amount of a platinum group element used, which can be early increased in temperature to a catalytically active temperature, which is suppressed in degradation in performance due to a catalyst poison included in an exhaust gas even if placed directly under an engine, and which is excellent in purification performance.

Abstract: A catalyst for removing nitrogen oxides, and the catalyst for removing the nitrogen oxides includes a first catalyst having a component including Pt, Ba, and Ce supported on a first support, and a second catalyst physically mixed with the first catalyst and having a component including Cu and Ce supported on a second support.

Abstract: The invention relates to a catalytic converter for removing carbon monoxide, hydrocarbons and nitrogen oxides from the exhaust gas of internal combustion engines operated with stoichiometric air-fuel mixture, which catalytic converter comprises a substrate of the length L and a catalytic coating, characterized in that the coating is located on the walls of the substrate and extends, proceeding from one end of the substrate, over a length corresponding to at least 50% of L and comprises active aluminum oxide, two cerium/zirconium/rare-earth-metal mixed oxides different from each other, and at least one platinum group metal.

Abstract: Doped nanoparticles, methods of making such nanoparticles, and uses of such nanoparticles. The nanoparticles exhibit a metal-insulator phase transition at a temperature of ?200° C. to 350° C. The nanoparticles have a broad range of sizes and various morphologies. The nanoparticles can be used in coatings and in device structures.

Abstract: A composition for exhaust gas purification including first alumina including alumina containing lanthanum and second alumina including alumina containing lanthanum. The first alumina has a higher lanthanum content than the second alumina. The second alumina has a larger particle size than the first alumina. The lanthanum content of the first alumina is preferably 2 to 12 mass %, in terms of oxide, based on the total mass of alumina and lanthanum oxide of the first alumina. The lanthanum content of the second alumina is preferably 9 mass % or less, in terms of oxide, based on the total mass of alumina and lanthanum oxide of the second alumina.

Abstract: Catalyst compositions, articles, systems and methods related to a three-way-catalyst composition comprising alumina doped with a transition metal.

Abstract: An aluminophosphate-metal oxide bonded body including a metal oxide having a bonding surface on a part of the surface thereof, and aluminophosphate that is disposed on the bonding surface of the metal oxide, wherein an alkali metal, an alkaline earth metal or both of these is/are disposed on the bonding surface of the metal oxide, and the content rate of the alkali metal, alkaline earth metal or both is from 0.3 to 30.0% by mass with respect to all of the substances that are disposed on the bonding surface of the metal oxide. An aluminophosphate-metal oxide bonded body that provides a favorable bonded state even for complicated shapes is provided.

Abstract: In an amorphous complex metal oxide and a method for producing the same of the present disclosure, the amorphous complex metal oxide is a three-components metal oxide containing titanium (Ti), cerium (Ce), and zirconium (Zr), wherein the amorphous complex metal oxide is amorphous.

Abstract: The invention relates to a particulate filter for removing particles, carbon monoxide, hydrocarbons and nitrogen oxides out of the exhaust gas of combustion engines operated with stoichiometric air/fuel mixture, comprising a wall flow filter with length L and a coating Z, wherein the wall flow filter includes channels E and A which 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 or OA, and wherein the channels E are closed at the second end and the channels A are closed at the first end, characterised in that coating Z is located in the porous walls and extends from the first end of the wall flow filter over the entire length L, and includes active aluminum oxide, two different cerium/zirconium/rare earth metal mixed oxides and at least one platinum group metal.

Abstract: The present disclosure provides catalytic materials and catalytic articles formed therewith. The catalytic materials particularly can include an oxygen storage component comprising a solid solution of at least one platinum group metal and at least one rare earth metal oxide. In one or more embodiments, catalytic materials can include a solid solution of a platinum group metal (e.g., palladium) and a mixed metal oxide (e.g., ceria/zirconia).

Abstract: An anode catalyst suitable for use in an electrolyzer. The anode catalyst includes a support and a plurality of catalyst particles disposed on the support. The support may include a plurality of metal oxide or doped metal oxide particles. The catalyst particles, which may be iridium, iridium oxide, ruthenium, ruthenium oxide, platinum, and/or platinum black particles, may be arranged to form one or more aggregations of catalyst particles on the support. Each of the aggregations of catalyst particles may include at least 10 particles, wherein each of the at least 10 particles is in physical contact with at least one other particle. The support particles and their associated catalyst particles may be dispersed in a binder.

Abstract: An object is to provide a means for suppressing a deterioration in catalytic performance even after being exposed to high temperature exhaust gas containing a phosphorus compound for a long period of time. An exhaust gas purifying catalyst including palladium supported on cerium-aluminum composite oxide containing cerium at from 3 to 60% by mass in terms of cerium oxide.

Abstract: An exhaust gas purifier is disposed in an exhaust gas passage of an engine, and includes: a DPF for capturing PM contained in exhaust gas; an SCR catalyst provided downstream of the DPF in a direction of flow of the exhaust gas, and for reducing NOx contained in the exhaust gas for purification in the presence of NH3; an injection unit provided between the DPF and the SCR catalyst, and for supplying urea to the SCR catalyst so as to supply NH3 to the SCR catalyst; and an AMOX provided downstream of the SCR catalyst in the direction of flow of the exhaust gas, and for removing NH3 having passed through the SCR catalyst. The DPF does not contain Pt or Pd, and contains Rh. The AMOX contains Pt.

Abstract: An exhaust gas purification catalyst of the present invention is provided with a base 10 and a catalyst coat layer 30. The catalyst coat layer is provided with Rh and Pd as noble metal catalysts. Herein Rh is disposed in a first-stage upper layer A and a second-stage upper layer C, and Pd is disposed in the first-stage upper layer A and a first-stage lower layer B, and in a second-stage lower layer D. A mass ratio (APd/ARh) of Pd to Rh, disposed in first-stage upper layer A is 0.5?(APd/ARh)?3.

Abstract: The present invention relates to a honeycomb structured body including a honeycomb fired body in which multiple through-holes are arranged longitudinally in parallel with one another with a partition wall therebetween, wherein the honeycomb fired body is an extrudate containing ceria-zirconia composite oxide particles, ?-alumina particles, ?-alumina, and ?-alumina fibers, and the honeycomb fired body has a porosity of 55 to 70%.

Abstract: A nitrous oxide (N2O) removal catalyst composition for treating an exhaust stream of an internal combustion engine is provided, containing a platinum group metal (PGM) component on a metal oxide-based support, wherein the N2O removal catalyst composition is in a substantially reduced form, such that it has an oxygen deficiency of about 0.05 mmol oxygen atoms/g or greater, and wherein the N2O removal catalyst composition provides effective removal of at least a portion of N2O from the exhaust stream under lean conditions at a temperature of about 350° C. or lower. N2O removal catalytic articles, systems, and methods are also provided for removing at least a portion of N2O from an exhaust stream under lean, low temperature conditions.

Abstract: An after treatment system is disclosed. The after treatment system may include an exhaust pipe through which an exhaust gas flows; a three-way catalyst (TWC) mounted on the exhaust pipe and purifying HC, CO, and NOx contained in the exhaust gas, an ammonia production catalyst (APC) mounted on the exhaust pipe at a downstream of the TWC, storing NOx at a lean air/fuel ratio, and generating H2, releasing the stored NOx, and generating NH3 using the released NOx and the generated H2 at a rich air/fuel ratio, and a selective catalytic reduction (SCR) catalyst mounted on the exhaust pipe at a downstream of the APC, storing the NH3 generated in the TWC and the APC, and reducing the NOx contained in the exhaust gas using the stored NH3.

Abstract: Catalyst/catalyst support compositions are characterized by a supported cerium oxide, deposited onto a silica, alumina, titanium or zirconium based support, including particles of said supported oxide deposited onto said support, individualized or in the form of aggregates, no greater than 500 nm in size and having, after 6 hours of calcination at a temperature of at least 800° C., a measured reducibility from 30° C. and 900° C. of at least 80%; such compositions are prepared by combining a colloidal dispersion of the supported oxide and a suspension of the support, drying the resulting mixture by atomization and drying the resulting product by calcination.

Abstract: A process for producing propylene glycol from glycerol including a catalyst of Cu and Ce at concentrations of up to 15% of each metal. In addition, it is described a catalyst of Cu and Ce to perform the selective reduction of glycerol and the process of production of such catalyst.

Abstract: A catalyst powder according to the present invention is a catalyst powder that includes: a core portion that contains ceria and zirconia; and a surface layer portion that is located on the core portion and contains ceria and zirconia. The ratio (M2/M1) is 0.30 or more and 0.95 or less, the ratio (M2/M1) being the ratio of a mole fraction M2 (mol %) of cerium in the surface layer portion measured using X-ray photoelectron spectroscopy to a mole fraction M1 (mol %) of cerium in the entire powder. It is preferable that the ratio (M4/2/M3/1) between M3/1 and M4/2 is 1.1 or more and 5.0 or less, wherein M3/1 (=M3/M1) represents the ratio between a mole fraction M3 (mol %) of zirconium in the entire powder and a mole fraction M1 (mol %) of cerium in the entirety of the powder, and M4/2 (=M4/M2) represents the ratio between a mole fraction M4 (mol %) of zirconium measured using X-ray photoelectron spectroscopy and a mole fraction M2 (mol %) of cerium measured using X-ray photoelectron spectroscopy.

Abstract: Methods and systems are featured for reducing harmful exhaust gas components of combustion devices such as gasoline-powered combustion engines (e.g., predominately stoichiometric running engines). The methods and systems include an underbody combination of a hydrocarbon trap (HCT), suited for cold start hydrocarbon adsorption, as well as an associated NOx trap. The system is inclusive of a control unit for extending a lean exhaust condition reaching the desorbing HCT as to avoid a deficiency in oxygen during the time period of HCT desorption. The system is also inclusive of one or more TWCs as in one associated with the underbody HCT-NOx-trap combination and/or one positioned in a close coupled position. Platinum group metals as in Pd, Rh and Pt are also featured on one, two or all three of the HCT, NOx-trap, and TWC when present.

Abstract: A three-way catalyst for purifying exhaust including noble metal components, enables sintering of the noble metal to be suppressed even at high temperature, enables carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NOx) to be removed and a method for purifying exhaust gas. A carrier having a honeycomb structure is coated with two or more layers of the catalyst compositions, an upper layer including a heat resistant inorganic oxide supporting Pd and a La-containing oxide, a lower layer including a heat resistant inorganic oxide supporting Rh. The content of La in terms of La2O3 is 9.6 g/L to 23 g/L, the content of Ce in terms of CeO2 is 5 g/L to 20 g/L, and the content of Ba in terms of BaO is 1.2 g/L or less per unit volume of the honeycomb structure.

Abstract: Methods and systems are provided for an exhaust aftertreatment arrangement. In one example, a system includes a LNT upstream of an SCR with an oxygen storage component arranged therebetween, and where a rich operation of an engine is limited based on an oxygen load of the oxygen storage component when an exhaust gas temperature is higher than a limit temperature.

Abstract: Provided is an electrocatalyst for anion exchange membrane water electrolysis, including a carbonaceous material, and nickel electrodeposited on the carbonaceous material, wherein nickel is partially substituted with platinum and the substitution with platinum provides increased hydrogen evolution activity as compared to the same electrocatalyst before substitution with platinum. Also provided are a method for preparing the electrocatalyst and an anion exchange membrane water electrolyzer using the same. The nickel electrocatalyst coated with an ultralow loading amount of platinum for anion exchange membrane water electrolysis shows excellent hydrogen evolution activity and has a small thickness of catalyst, thereby providing high mass transfer and high catalyst availability.

Abstract: An overall exhaust gas purification function based on an NOx reduction function and an HC oxidation function in an NSR catalyst arranged in an exhaust passage of an internal combustion engine is improved. In the NSR catalyst, a portion of an NOx storage catalyst layer supported by a carrier, which extends from its upstream end to an X % (0<X?75) of an overall length thereof along the flow of exhaust gas, forms an upstream side catalyst layer, and a portion of the NOx storage catalyst layer at the downward side of the upstream side catalyst layer along the flow of exhaust gas forms a downstream side catalyst layer. The upstream side catalyst layer does not contain potassium (K) as an NOx storage material, but the downstream side catalyst layer contains potassium (K) as an NOx storage material.

Abstract: An exhaust gas purification device which has improved exhaust gas purification performance. An exhaust gas purification device which includes a first catalyst layer that contains: a Pd-supporting catalyst which is obtained by having alumina carrier particles support Pd; a first Rh-supporting catalyst which is obtained by having first ceria-zirconia carrier particles support Rh; and second ceria-zirconia carrier particles. This exhaust gas purification device is configured such that: the ceria concentration in the first ceria-zirconia carrier particles is 30 wt % or less; and the amount of ceria in the second ceria-zirconia carrier particles is larger than the amount of ceria in the first ceria-zirconia carrier particles.

Abstract: A substrate for a catalytic converter, comprising an open cell carbon foam having a geometric surface area of at least about 5000 m2/m3 and a permeability of at least about 8.0 darcys, wherein the substrate has a catalytic material which includes non-noble metal nano-scale catalyst particles.

Abstract: Provided are: a complex oxide that exhibits high redox ability even at low temperatures, has excellent heat resistance, and stably retains these characteristics even on repeated oxidation and reduction at high temperature; a method for producing the same; and an exhaust gas purification catalyst. The inventive complex oxide contains Ce; rare earth metal element other than Ce, including Y; Al and/or Zr; and Si; such that the Ce, and said other elements other than Ce and Si, are present in a mass ratio of 85:15-99:1, calculated as oxides; and has a characteristic such that when it is subjected to temperature-programmed reduction (TPR) measurement in a 10% hydrogen-90% argon atmosphere at from 50° C. to 900° C. with the temperature increasing at a rate of 10° C./min, followed by oxidation treatment at 500° C. for 0.5 hours, and then temperature-programmed reduction measurement is performed again, its calculated reduction rate at and below 400° C. is at least 2.0%.

Abstract: The present invention relates to an electrochemical catalyst structure and a method for producing the same. The electrochemical catalyst structure may include a catalyst layer including a perovskite based oxide as an electrochemical oxygen reduction catalyst; and a modifying layer being in contact with the catalyst layer and including a transition metal oxide capable of chemical interaction with a metal of the perovskite based oxide through electron orbital hybridization.

Abstract: A method for the preparation of a catalyzed monolithic body or a catalyzed particular filter. The method includes the step of suctioning a sol-solution containing catalytically active material and metal oxide catalyst carriers or precursors thereof into pores of a monolithic substrate, solely by capillary forces and without the application of vacuum or pressure.

Abstract: A composition of formula Ce1-a-b-cNaMbDcOx??I wherein M stands for one or more elements from the group of alkaline metals, except sodium, N is Bi and/or Sb, D is present, or is not present, and if present is selected from one or more of Mg, Ca, Sr, Ba; Y, La, Pr, Nd, Sm, Gd, Er; Fe, Zr, Nb, Al; a is a number within the range of 0<a?0.9, b is a number within the range of 0<b?0.3, c is a number within the range of 0<c?0.2, a plus b plus c is <1, and x is a number within the range of 1.2?x?2, and its use for exhaust gas aftertreatment systems of Diesel engines, gasoline combustion engines, lean burn engines and power plants.

Abstract: The present invention involves micron-scale cerium oxide particles having a multi-cores single-shell structure, comprising: a cerium oxide shell, the shell being composed of crystalline and/or amorphous nano-scale cerium oxide particles; and a plurality of nano-scale cerium oxide grain cores aggregates located in the interior of the shell. Also involved is a preparation method for the micron-scale cerium oxide particle having a multi-cores single-shell structure. A supported catalyst with the micron-scale cerium oxide particles according to the invention as the support have good hydrothermal stability and good sulfur resistance, and the active components of the supported catalyst are not easily embedded, and the supported catalyst has a great application prospect in the field of catalytic oxidation of exhaust emissions such as CO, NO or volatile organic compounds.

Abstract: A photocatalytic system having enhanced photo efficiency/photonic efficacy is provided that includes a thin nucleation material coated on a substrate. The nucleation material enhances lattice matching for a subsequently deposited photocatalytic active material. Such a photocatalytic system may be used as a self-cleaning surface in an application where removal of fingerprints and other residue is desired. In certain aspects, the nucleation material comprises aluminum oxide (Al2O3) and the photocatalytic material comprises an anatase phase of titanium dioxide (TiO2) deposited over the nucleation material. A photocatalytic activity of the system is ?about 50% above a comparative photocatalytic activity where the photocatalytic active material is disposed directly on the substrate. Methods of making such photocatalytic systems are also provided.

Abstract: Described is a catalyst composition suitable for use as a selective catalytic reduction catalyst, including small-pore molecular sieve particles having a pore structure and a maximum ring size of eight tetrahedral atoms and impregnated with a promoter metal, and metal oxide particles dispersed within the small-pore molecular sieve particles and external to the pore structure of the small-pore molecular sieve particles, wherein the metal oxide particles include one or more oxides of a transition metal or lanthanide of Group 3 or Group 4 of the Periodic Table. A method for preparing the catalyst, a method for selectively reducing nitrogen oxides, and an exhaust gas treatment system are also described.

Abstract: The present invention relates to a catalyst comprising two layers on an inert catalyst carrier, wherein a layer A lying directly on the catalyst carrier contains at least one platinum group metal and one cerium/zirconium/SE mixed oxide, and a layer B, applied on layer A and in direct contact with the flow of exhaust gas, contains at least one platinum group metal and a cerium/zirconium/SE mixed oxide, wherein SE stands for a rare earth metal other than from cerium, characterized in that the fraction of SE oxide in the cerium/zirconium/SE mixed oxide of layer A is less than the fraction of SE oxide in the cerium/zirconium/SE mixed oxide of layer B.

Abstract: An oxidation catalyst device for exhaust gas purification, having a first catalyst coating layer on the exhaust gas flow's upstream side, second catalyst coating layer of an upper layer on exhaust gas flow's downstream side, and third catalyst coating layer of a lower layer on exhaust gas flow's downstream side, on a substrate, wherein the weight ratio of platinum to palladium in the first catalyst coating layer is 0.75 to 4.50, weight ratio of platinum to palladium in second catalyst coating layer is greater than 4.50 to 25.0, weight ratio of platinum to palladium in third catalyst coating layer is 0.12 or less, the length of first catalyst coating layer is 8% to 55% of the substrate's length, length of second catalyst coating layer is 45% to 95% of the substrate's length, and length of third catalyst coating layer is 45% to 95% of the substrate's length.

Abstract: An object of the present disclosure is to provide an exhaust gas purification catalyst demonstrating superior storage of NOx contained in exhaust gas. The exhaust gas purification catalyst of the present disclosure has a substrate, a first catalyst layer containing a catalytic metal for NOx reduction and a NOx storage material and formed on the substrate, and a second catalyst layer containing a catalytic metal for NOx oxidation and formed on the first catalyst layer. In the exhaust gas purification catalyst of the present disclosure, the value obtained by dividing the volume of all large pores having a pore volume of 1000 ?m3 or more by the total volume of all medium pores of having a pore volume of 10 ?m3 to 1000 ?m3 in the second catalyst layer is 2.44 or less.

Abstract: A catalyst body which includes ceria:zirconia and a metal-zeolite, and is substantially free, or free, of tungsten or tungsten compounds, and methods of manufacture. The ceria and zirconia are present with a zirconia/ceria mole ratio of less than or equal to 1.0. The catalyst body is especially useful in NOx reduction applications.

Abstract: An embodiment relates to a composition including at least two powders. The powders are selected from the group including a powder including a p-doped perovskite; a powder including an n-doped perovskite; and a powder including an undoped perovskite. A method for producing the composition, a method for producing a detector using the composition, and a detector, in particular an X-ray detector, produced thereby are also disclosed.

Abstract: Fluidizable catalysts for the gas phase oxygen-free oxidative cracking of alkanes, such as hexane, to one or more olefins, such as ethylene, propylene, and/or butylene. The catalysts comprise 1-15% by weight per total catalyst weight of one or more vanadium oxides (VOx), such as V2O5. The catalysts are disposed on an alumina support that is modified with cerium to influence catalyst acidity and characteristics of lattice oxygen at the catalyst surface. Various methods of preparing and characterizing the catalyst as well as methods for the gas phase oxygen free oxidative cracking of alkanes, such as hexane, to one or more olefins, such as ethylene, propylene, and/or butylene with improved alkane conversion and olefins product selectivity are also disclosed.

Abstract: Provided are a composite oxide which is suitable as a co-catalyst for an exhaust gas purifying catalyst or the like, has high heat resistance, and has an excellent oxygen absorbing and desorbing capability at low temperatures and a method for producing the composite oxide. The composite oxide contains Ce and Zr, wherein the Ce content is 30 to 80 at % and the Zr content is 20 to 70 at %, based on the total of Ce and Zr being 100 at %, or further contains particular element M, wherein the Ce content is not less than 30 at % and less than 80 at %, the Zr content is not less than 20 at % and less than 70 at %, and the content of element M is more than 0 at % and not more than 15 at %, based on the total of Ce, Zr, and element M being 100 at %.

Abstract: An oxygen storage material comprises three pyrochlore-type composite oxides which are a ceria-zirconia composite oxide, a lanthana-zirconia composite oxide, and a ceria-zirconia-lanthana composite oxide, and which coexist together, wherein the oxygen storage material contains: first secondary particles made of the pyrochlore-type ceria-zirconia composite oxide and the pyrochlore-type ceria-zirconia-lanthana composite oxide; and second secondary particles made of the pyrochlore-type lanthana-zirconia composite oxide and the pyrochlore-type ceria-zirconia-lanthana composite oxide.

Abstract: An exhaust gas purifying catalyst with an excellent effect of suppressing deterioration due to aggregation of a noble metal catalyst during endurance at high temperature, and a production method therefor. The method for producing the exhaust gas purifying catalyst that has a porous carrier and a noble metal catalyst supported thereon includes: preparing the porous carrier that contains alumina-ceria-zirconia composite oxide particles and has physical property values, after subjected to baking at 900° C. for 5 hours, of a pore diameter of the particles in the range of 2 to 20 nm, a specific surface area of the particles in the range of 75 to 115 m2/g, a crystallite size of a ceria-zirconia composite oxide contained in the particles in the range of 4 to 6 nm, and a bulk density of the particles in the range of 0.5 to 0.

Abstract: A lean NOx trap (LNT) catalyst includes a plurality of carriers connected to each other in series, wherein each of the carriers is embedded with at least one of a first wash coat containing magnesium (Mg)-substituted alumina, ceria (CeO2), barium (Ba), and a precious metal, a second wash coat containing magnesium (Mg)-substituted alumina, ceria (CeO2), barium (Ba), a third wash coat containing magnesium (Mg)-substituted alumina, ceria (CeO2), and a fourth wash coat containing magnesium (Mg)-substituted alumina, ceria (CeO2), and a higher content of a precious metal than the first wash coat, a ratio of the magnesium-substituted alumina to ceria (CeO2) being lower than that of the third wash coat, wherein the third and first wash coats are disposed in a foremost carrier through which exhaust gas passes sequentially from a front portion of the foremost carrier.