A production method comprising: adding a hydroxycarboxylic acid to an aqueous solution containing a Ce salt, a Zr salt, an Al salt, and at least one selected from a La salt, an Mg salt, and a Ca salt, to produce a gel, heating the gel to obtain a solid product by decomposition of the salts, firing the solid product to obtain a fired product containing a ceria-zirconia-based regular array phase precursor and an aluminate-based composite oxide precursor, performing a reducing heat treatment of the fired product to obtain a first composite having mutually dispersed therein a pyrochlore phase and an aluminate-based composite oxide, and performing an oxidizing heat treatment of the first composite to obtain a second composite in which at least part of the pyrochlore phase is transformed into a phase; and an oxygen storage material having mutually dispersed therein the composite oxide and the regular array phase.

The present disclosure relates to a substrate comprising nanoparticle catalysts and NO.sub.x storage materials for treatment of gases, and washcoats for use in preparing such a substrate. Also provided are methods of preparation of the nanoparticle catalysts and NO.sub.x storage materials, as well as methods of preparation of the substrate comprising the nanoparticle catalysts and NO.sub.x storage materials. More specifically, the present disclosure relates to a coated substrate comprising nanoparticle catalysts and NO.sub.x storage materials for lean NO.sub.x trap (LNT) systems, useful in the treatment of exhaust gases.

A nanocrystal-sized cerium-zirconium-aluminum mixed oxide material includes at least 20% by mass zirconium oxide; between 5% to 55% by mass cerium oxide; between 5% to 60% by mass aluminum oxide; and a total of 25% or less by mass of at least one oxide of a rare earth metal selected from the group of lanthanum, neodymium, praseodymium, or yttrium. The nanocrystal-sized cerium-zirconium-aluminum mixed oxide exhibits hierarchically ordered aggregates having a dso particle size less than 1.5 m, and retains at least 80% of surface area and pore volume after ageing at temperature higher than 1000 C. for at least 6 hours. The nanocrystal-sized cerium-zirconium-aluminum mixed oxide material is prepared using a co-precipitation method followed by milling the dried and calcined oxide material. The nanocrystal-sized cerium-zirconium-aluminum mixed oxide material forms a particulate filter that may be used in an exhaust system arising from a gas or diesel engine.

The present invention relates to a rhodium-free TWC catalytic article, which comprises a catalyst composition coat on a substrate, wherein the catalyst composition coat comprises, a first region comprising i). a top layer comprising a first platinum component and a first palladium component, each being present in supported form, and ii). a bottom layer comprising a second platinum component in supported form, andoptionally, a second region located downstream of the first region, and comprising iii). a top layer comprising a third platinum component in supported form, and iv). a bottom layer comprising a fourth platinum component in supported form. The present invention relates to an exhaust treatment system comprising the rhodium-free TWC catalytic article.

Provided herein are zoned catalysts that utilize components efficiently in that relatively short zones are provided to achieve specific functionalities to convert and/or trap one or more components in the exhaust stream. Highly controlled zoned are formed from one end of a monolithic carrier. The zones have a flat profile such that the zoned catalytic material within each passage of the substrate is at a substantially uniform distance from one end of the carrier. Methods of making and using the same are also provided.

A catalytically active material is provided. The material includes a mixed oxide having a first metal selected from group 4 of the periodic table of elements and/or a second metal, and at least one further metal selected from group 11 of the periodic table of elements, wherein the macroscopic composition of the material given by the chemical formula corresponds to the composition of the material at a molecular level. A coating made of such a material is also provide, as is an article having such a coating, and a method for producing such a material.

Zeolite catalysts and systems and methods for preparing and using zeolite catalysts having the CHA crystal structure are disclosed. The catalysts can be used to remove nitrogen oxides from a gaseous medium across a broad temperature range and exhibit hydrothermal stable at high reaction temperatures. The zeolite catalysts include a zeolite carrier having a silica to alumina ratio from about 15:1 to about 256:1 and a copper to alumina ratio from about 0.25:1 to about 1:1.

An ammonia slip control catalyst having a layer containing perovskite and a separate layer containing an SCR catalyst is described. The ammonia slip catalyst can have two stacked layers, with the top overlayer containing an SCR catalyst, and the bottom layer containing a perovskite. The ammonia slip catalyst can alternatively be arranged in sequential layers, with the SCR catalyst being upstream in the flow of exhaust gas relative to the perovskite. A system comprising the ammonia slip catalyst upstream of a PGM-containing ammonia oxidation catalyst and methods of using the system are described. The system allows for high ammonia oxidation with good nitrogen selectivity. Methods of making and using the ammonia slip catalyst to reduce ammonia slip and selectively convert ammonia to N.sub.2 are described.

In the plugged honeycomb structure, 30% or more of first intersection portions in which a first partition wall intersects a second partition wall are first specific intersection portions in which a diameter of a maximum inscribed circle drawn in the first intersection portion is a specific size for a shortest distance between an inflow cell and an outflow cell, and 30% or more of non-first intersection portions other than the first intersection portions are non-first specific intersection portions in which a diameter of a maximum inscribed circle drawn in a non-first intersection portion is a specific size for a shortest distance between the inflow cells or the outflow cells.

The present disclosure features a method of making an engine aftertreatment catalyst, where the engine aftertreatment catalyst includes a metal oxide, a metal zeolite, and/or vanadium oxide when the metal oxide is different from vanadium oxide, each of which can be independently surface-modified with a surface modifier. The method includes providing a solution including an organic solvent and an organometallic compound; mixing the solution with a metal oxide, a metal zeolite, and/or a vanadium oxide to provide a mixture; drying the mixture; and calcining the mixture to provide a surface-modified metal oxide catalyst, a surface-modified metal zeolite catalyst, and/or a surface-modified vanadium oxide catalyst. The organometallic compound can be, for example, a metal alkoxide, a metal carboxylate, a metal acetylacetonate, and/or a metal organic acid ester.