A three-way catalyst article, and its use in an exhaust system for internal combustion engines, is disclosed. The catalyst article for treating exhaust gas comprising: a substrate comprising an inlet end, an outlet end with an axial length L; an inlet catalyst layer beginning at the inlet end and extending for less than the axial length L, wherein the inlet catalyst layer comprises an inlet palladium component; an outlet catalyst layer beginning at the outlet end and extending for less than the axial length L, wherein the outlet catalyst layer comprises an outlet rhodium component; and wherein the outlet catalyst layer overlaps with the inlet catalyst layer.

The present disclosure provides an exhaust gas purification catalyst having an improved Rh activation, which comprises a substrate and a catalyst coat layer formed on the substrate, the catalyst coat layer having a two-layer structure, wherein the catalyst coat layer includes an upstream portion on an upstream side and a downstream portion on a downstream side in an exhaust gas flow direction, and a part or all of the upstream portion is formed on a part of the downstream portion, wherein the upstream portion contains Rh fine particles and Pt, wherein the Rh fine particles have an average particle size measured by a transmission electron microscope observation of 1.0 nm or more to 2.0 nm or less, and a standard deviation σ of the particle size of 0.8 nm or less, and wherein the downstream portion contains Rh.

The present invention relates to a catalyst comprising two layers on an inert catalyst carrier, a layer A containing at least palladium as a platinum group metal, in addition to a cerium/zirconium/lanthanum/yttrium mixed oxide, and a layer B, which is applied to layer A, containing at least rhodium as the platinum group metal, in addition to a cerium/zirconium/lanthanum/yttrium mixed oxide.

A exhaust gas purification apparatus is provided with: a substrate having a wall-flow structure and including entry-side cells, exit-side cells, and a porous partition; a first catalyst region formed in small diameter pores having relatively small pore diameters among internal pores in the partition; and a second catalyst region formed in large diameter pores having relatively large pore diameters among the internal pores in the partition. The first catalyst region contains a support and any one or two species of precious metal selected from Pt, Pd, and Rh loaded on the support, while the second catalyst region contains a support and any one or two species of precious metal selected from Pt, Pd, and Rh loaded on the support and other than at least the precious metal present in the first catalyst region.

This invention relates to a catalyst for use in the preparation of acetic acid through a methanol carbonylation reaction using carbon monoxide, and particularly to a heterogeneous catalyst represented by Rh/C.sub.3N.sub.4 configured such that a complex of a rhodium compound and 3-benzoylpyridine is immobilized on a carbon nitride support.

A method of manufacturing a catalyst article, the method comprising: providing a complex of a humic acid or derivative thereof, and a PGM; 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.

A supported catalyst having rhodium particles with an average diameter of less than 1 nm disposed on a support material containing magnetic iron oxide (e.g. Fe.sub.3O.sub.4). A method of producing the supported catalyst and a process of reducing nitroarenes to corresponding aromatic amines employing the supported catalyst with a high product yield are also described. The supported catalyst may be recovered with ease using an external magnet and reused.

Catalyst compositions to perform selective alkyl-demethylation of C2+-hydrocarbyl-substituted aromatic hydrocarbon may exhibit a hydrogen chemisorption of at least 15% and comprise an oxide support material selected from the group consisting of an alkaline earth metal oxide, silica, a composite of an alkaline earth metal oxide and Al.sub.2O.sub.3, a composite of ZnO and Al.sub.2O.sub.3, a lanthanide oxide, a composite of a lanthanide oxide and Al.sub.2O.sub.3, and combinations and mixtures of two or more thereof; and a transition metal element dispersed upon the oxide support material. Alkyl-demethylation processes of a C6+ aromatic hydrocarbon-containing stream comprising C2+-hydrocarbyl-substituted aromatic hydrocarbons may comprise contacting the catalyst compositions in an alkyl-demethylation zone under alkyl-demethylation conditions to form an alkyl-demethylated aromatic hydrocarbon as an effluent exiting the alkyl-demethylation zone.

Disclosed are catalyst compositions comprising two or more metal elements with high performances for selective alkyl-demethylation of C2+-hydrocarbyl-substituted aromatics, processes for making such catalyst compositions, and alkyl-demethylation processes using same. Also disclosed are preferred processes for making alkyl-demethylation catalyst compositions including a high-temperature calcination step, and preferred alkyl-demethylation processes having a high H.sub.2/HC molar ratio.

An object of the present invention is to provide an exhaust gas purification catalyst including a wall-flow substrate and a catalyst layer, and having an improved exhaust gas purification performance, and, in order to achieve such an object, the present invention provides an exhaust gas purification catalyst including: a wall-flow substrate, first catalyst layers; and second catalyst layers; wherein the first catalyst layers and the second catalyst layers satisfy the following expressions (1) to (3):

L1<L2  (1)

T1<T2  (2)

WC1>WC2  (3)

wherein L1 represents the length of the first catalyst layers, L2 represents the length of the second catalyst layers, T1 represents the thickness of the rising portions of the first catalyst layers, T2 represents the thickness of the rising portions of the second catalyst layers, WC1 represents the mass of the first catalyst layers per unit volume of the portion of the substrate provided with the first catalyst layers, and WC2 represents the mass of the second catalyst layers per unit volume of the portion of the substrate provided with the second catalyst layers.