Exhaust gas purification catalyst article with enriched PGM zone, method and apparatus for making same

Abstract

The presently claimed invention is an exhaust purification catalyst article comprising: a substrate having an inlet axial end and an outlet axial end; a bottom washcoat layer coated on 60 to 100% of the length of the substrate from the inlet axial end to the outlet axial end; and a top washcoat layer coated on 60 to 100% of the length of the substrate from the inlet axial end or the outlet axial end or both ends of the substrate so that the topcoat covers at least 60% of the length of the bottom washcoat layer; and a control arm device connected to the spray nozzle, the control arm device enabling 3D positioning of the nozzle relative to the substrate surface to accommodate radial and / or radial deposition of the platinum-group metal in the individual channels.

Description

[Technical Field]

[0001] Cross-reference of related applications This application claims priority over U.S. Provisional Application No. 62 / 950,265, filed on 19 December 2019.

[0002] The currently claimed invention relates to exhaust gas purification catalyst articles useful for treating exhaust gas and reducing the pollutants contained therein, and to methods and apparatus for preparing said exhaust gas purification catalysts. In particular, the currently claimed invention relates to exhaust gas purification catalyst articles having axially and / or radially concentrated PGM zones and methods, and to apparatus for preparing catalyst articles. [Background technology]

[0003] Three-way converter (TWC) catalysts (hereinafter interchangeably referred to as three-way converter catalysts, three-way catalysts, TWC catalysts, and TWC) have been used for several years to treat exhaust gas flows from internal combustion engines. Generally, catalytic converters containing three-way converter catalysts are used in the exhaust gas lines of internal combustion engines to treat or purify exhaust gases containing pollutants such as hydrocarbons, nitrogen oxides, and carbon monoxide. Three-way converter catalysts are typically known to oxidize unburned hydrocarbons and carbon monoxide and reduce nitrogen oxides. Most commercially available TWC catalysts contain palladium as the main platinum group metal component, often used in smaller amounts with rhodium.

[0004] The catalyst is formed by coating a substrate with a platinum group metal-containing slurry, and the coated layer may be in the form of a layered structure having a bottom layer and a top layer. The platinum group metal is present in a concentration of 3 to 300 g / ft. 3 The substrate is uniformly coated with PGM impregnation within a range of [specify range]. In another technique, platinum group metals are coated onto the substrate in a zone manner.

[0005] However, NO xTo achieve a higher reduction in pollutants such as HC and CO, it is evident that existing catalysts still need improvement in terms of washcoat structure, PGM type and amount of impregnation, and coating strategy and method.

[0006] Therefore, in order to achieve a significantly high reduction in pollutants, high levels of PGM impregnation (maximum 1000g / ft) are required. 3 It is envisioned that additional PGM enrichment zones may be applied, which can be deposited in the bottom or top layer at the inlet or outlet portions of the substrate in the axial and / or radial zones, including the axial and / or radial zones. The above design approach allows for the formation of complex PGM enrichment structures, such as inverted conical pyramids, vortices, or star patterns extending into the underlying washcoat. [Overview of the Initiative]

[0007] The present invention relates to an exhaust gas purification catalyst article, A base material having an inlet axial end and an outlet axial end, A bottom wash coat layer is coated over 60-100% of the length of the substrate from the inlet axial end to the outlet axial end, A top wash coat layer comprising a top wash coat layer, wherein the top coat is coated from the inlet axial end or the outlet axial end, or both ends, of the substrate to a length of 60-100% of the substrate, so as to cover at least 60% of the length of the bottom wash coat layer, At least a portion of the top wash coat layer and / or bottom wash coat layer comprises a first portion and a second portion, wherein the first portion begins at the inlet axial end or the outlet axial end of the substrate and exhibits a platinum group metal concentration 2 to 100 times higher than the platinum group metal concentration in the second portion. The first portion constitutes 5-50% of the substrate volume and exhibits a three-dimensional axial and / or radial zone arrangement starting from the inlet axial end or the outlet axial end of the substrate, or both. If the amount of platinum group metal impregnation in the first portion is determined axially from the first end of the first portion to the second end of the first portion, then 10 to 1000 g / ft 3 The present invention provides an exhaust gas purification catalyst article.

[0008] According to another aspect of the currently claimed invention, a process for preparing an exhaust gas purification catalyst article is also provided, which includes using a spray nozzle device to create a three-dimensional axial and / or radial zone arrangement for platinum group metal enrichment.

[0009] According to yet another aspect of the currently claimed invention, the apparatus comprises a PGM precursor solution storage unit, a dispensing unit for the PGM precursor solution, at least one PGM precursor solution supply pipe connected to the dispensing unit, a spray nozzle connected to the dispensing unit via a second supply pipe, an optional control arm device connected to the spray nozzle connected to an air supply means, the control arm device being adapted to enable 3D positioning of the nozzle with respect to a substrate surface, an optional additional air supply or bypass means, and an optional vacuum function, wherein the apparatus is adapted to spray the PGM precursor solution and produce a three-dimensional axial and / or radial zone arrangement including a geometric shape starting from the inlet or outlet axial end of the substrate. [Brief explanation of the drawing]

[0010] To provide an understanding of embodiments of the present invention, the accompanying drawings are referenced, which are not necessarily drawn to scale, and the reference numbers refer to components of exemplary embodiments of the present invention. The drawings are illustrative only and should not be construed as limiting the present invention. The above and other features of the present claimed invention, their nature, and various advantages will become more apparent when considered in conjunction with the accompanying drawings in the following detailed description.

[0011] [Figure 1]Schematic diagram of an apparatus (100) for depositing a sprayed PGM precursor solution onto a blank or wash-coated catalyst substrate. [Figure 2] Schematic diagram of a catalyst article design in an exemplary configuration according to some embodiments of the presently claimed invention. [Figure 3] Shows the comparison results of the light-off performance between a reference catalyst and an inventive catalyst with the same PGM loading. [Figure 4A] Perspective view of a honeycomb-type substrate carrier that may include a catalyst composition according to an embodiment of the presently claimed invention. [Figure 4B] An enlarged partial cross-sectional view taken along a plane parallel to the end face of the substrate carrier of FIG. 4A, and an enlarged view of a plurality of gas flow paths shown in FIG. 4A. [Figure 5] A broken view of an enlarged cross-section of FIG. 4A, where the honeycomb-type substrate of FIG. 4A represents a wall-flow filter substrate monolith.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Here, the presently claimed invention will be more fully described hereinafter. The presently claimed invention may be embodied in many different forms and should not be construed as limited to the embodiments described herein. Rather, these embodiments are provided so that this application will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. No language in this specification should be construed as indicating any non-claimed element as essential to the practice of the disclosed materials and methods.

[0013] The use of the terms "a", "an", "the", and similar indicatives in the context of describing the materials and methods considered herein (particularly in the context of the following claims) is to be construed to cover both the singular and the plural unless otherwise indicated herein or clearly contradicted by the context.

[0014] The term “about” as used throughout this specification is used to describe and clarify small variations. For example, the term “about” refers to ±5% or less, e.g., ±2% or less, ±1% or less, ±0.5% or less, ±0.2% or less, ±0.1% or less, or ±0.05% or less. All numbers are modified by the term “about,” whether explicitly stated or not. Of course, values ​​modified by the term “about” include a specific value. For example, “about 5.0” must include 5.0.

[0015] All methods described herein may be performed in any preferred order, unless otherwise indicated herein or unless clearly contradicted by the context. The use of any and all examples or illustrative language provided herein (e.g., "etc.") is intended solely to better describe the materials and methods and is not intended to limit their scope unless otherwise requested.

[0016] Platinum group metal (PGM) components refer to any components containing PGMs (Rh, Pd, and Pt). For example, PGMs may be in a metallic form with zero valence, or they may be in an oxide form. References to “PGM components” take into account the presence of PGMs in any valence electron state. Terms such as “platinum (Pt) component,” “rhodium (Rh) component,” and “palladium (Pd) component” refer to the respective platinum group metal compounds, complexes, etc., that decompose or are converted into catalytically active forms, usually metals or metal oxides, during the calcination or use of the catalyst.

[0017] As used herein, the terms “catalyst” or “catalytic composition” refer to a material that facilitates a reaction.

[0018] The terms "catalytic article" or "catalyst article" refer to a substrate coated with a catalytic component used to promote a desired reaction. In one embodiment, the catalytic article is a layered catalytic article. The term layered catalytic article refers to a catalytic article in which a substrate is coated in layers with a PGM composition. These compositions may be referred to as washcoats.

[0019] "NO x The term "NO" refers to nitrogen oxide compounds such as NO and / or NO2.

[0020] In one embodiment, the currently claimed invention provides an exhaust gas purification catalyst article comprising a substrate having an inlet axial end and an outlet axial end, wherein the catalyst article is A bottom wash coat layer is coated over 60-100% of the length of the substrate from the inlet axial end to the outlet axial end, A top wash coat layer is provided, wherein the top coat is coated from the inlet axial end or outlet axial end of the substrate, or both ends, to a length of 60-100% of the substrate, so as to cover at least 60% of the length of the bottom wash coat layer. At least a portion of the top wash coat layer and / or bottom wash coat layer comprises a first portion and a second portion, wherein the first portion begins at the inlet axial end or the outlet axial end of the substrate and exhibits a platinum group metal concentration 2 to 100 times higher than the platinum group metal concentration in the second portion. The first portion constitutes 5-50% of the substrate volume and exhibits a three-dimensional axial and / or radial zone arrangement starting from the inlet axial end or the outlet axial end of the substrate, or both. If the amount of platinum group metal impregnation in the first portion is determined axially from the first end of the first portion to the second end of the first portion, then 10 to 1000 g / ft 3 It is an exhaust gas purification catalyst article.

[0021] According to the invention claimed in this application, a three-dimensional axial and / or radial zone arrangement starting from the inlet axial end or the outlet axial end, or both, is a geometric shape having a base that covers 20-100% of the substrate surface from each substrate end and having a volume of 5-50% of the substrate volume. In the context of the present invention, the terms “inlet axial end” and “outlet axial end” can be used interchangeably with “first axial end” and “second axial end,” respectively. In one embodiment, the first portion has an axial length ranging from 5-50% of the substrate from the inlet end or outlet end and covers 20-100% of the inlet or outlet surface of the substrate, such that the total volume of the formed geometric shape is 5-50% of the substrate volume. The arrangement of three-dimensional axial and / or radial zones includes geometric shapes selected from cones, tapered cones, asymmetric cones, round cylinders, elliptical cylinders, polygonal cylinders, round pyramids, elliptical pyramids, polygonal pyramids, cubes, parabolas, semi-elliptic shapes, hemispheres, polygonal prisms, parallelepipeds, rhombohedrons, polyhedra, and hyperbolas. The arrangement of three-dimensional axial and / or radial zones having geometric shapes, starting from the inlet axial end or the outlet end, or both, is produced by coating the substrate axially, radially, or simultaneously in the axial and radial directions using a spray nozzle or a device equipped with a spray nozzle. The first portion of the top or bottom wash coat is referred to as a concentrated zone formed by coating at least a portion of the top wash coat layer and / or bottom wash coat layer, in which platinum group metals are optionally pre-impregnated over the entire length of the substrate, with an additional platinum group metal solution deposited in a sprayed manner. The platinum group metals used in the wash coat or concentration zone are selected from platinum, palladium, rhodium, and combinations thereof.Platinum group metals are typically supported on a carrier selected from an oxygen storage component, an alumina component, a ceria component, a zirconia component, and combinations thereof, wherein the alumina component includes alumina, lantana-alumina, ceria-alumina, ceria-zirconia-alumina, zirconia-alumina, lantana-zirconia-alumina, barrier-alumina, barrier-lantana-alumina, barrier-lantana-neodymia-alumina, or combinations thereof, and the oxygen storage component is ceria-zirconia The material comprises conia, ceria-zirconia-lantana, ceria-zirconia-yttria, ceria-zirconia-lantana-yttria, ceria-zirconia-neodymia, ceria-zirconia-praseodymia, ceria-zirconia-lantana-neodymia, ceria-zirconia-lantana-praseodymia, ceria-zirconia-lantana-neodymia-praseodymia, or any combination thereof, wherein the zirconia component comprises lantana-zirconia and barium-zirconia. According to one embodiment of the present invention, at least 40-100% of the platinum group metals in the first part are distributed through the wash coat within the first part with a gradient of 50% or less, as determined by an electron probe micro-analysis (EPMA) line scan from the top layer of the first part to the substrate. In another embodiment, more than 50% of the platinum group metals in the first portion are present in the top third of the first portion, as determined by an electron probe microanalysis (EPMA) line scan from the top layer of the first portion of the concentrated washcoat layer to the substrate. In one embodiment, 50% to 95% of the platinum group metals in the first portion are present in the top third of the first portion, as determined by an electron probe microanalysis (EPMA) line scan from the top layer of the first portion of the concentrated washcoat layer to the substrate. In some embodiments, the first portion contains palladium. The amount of palladium in the first portion is 30 to 100% by weight of the total palladium present in the catalyst article. In another embodiment, the first portion contains platinum. The amount of platinum in the first portion is 30 to 100% by weight of the total platinum present in the catalyst article. In yet another embodiment, the first portion contains rhodium.In one embodiment, the weight ratio of the platinum group metal in the first portion to the platinum group metal in the second portion is 4.0 to 50.

[0022] In one exemplary embodiment, the exhaust gas purification catalyst article is: A bottom wash coat layer comprising palladium or platinum deposited on a carrier selected from an oxygen storage component, an alumina component, and a combination thereof, and coated over a length of 60-100% of the substrate from the inlet axial end to the outlet axial end, At least a portion of the bottom wash coat layer includes a first portion and a second portion, The first portion comprises palladium or platinum, optionally supported on a carrier selected from an oxygen storage component, an alumina component, and combinations thereof, beginning at the inlet axial end or the outlet axial end of the substrate. The concentration of palladium or platinum in the first part is 2 to 100 times higher than the concentration of palladium or platinum in the second part. The first portion constitutes 5-50% of the substrate volume and exhibits a three-dimensional axial and / or radial zone arrangement starting from the inlet axial end or the outlet axial end of the substrate, or both. If the amount of platinum group metal impregnation in the first portion is determined axially from the first end of the first portion to the second end of the first portion, then 10 to 1000 g / ft 3 The bottom wash coat layer, The invention comprises a top wash coat layer, the top coat comprising rhodium, platinum, or a combination thereof, impregnated on a carrier selected from an oxygen storage component, an alumina component, and a combination thereof, such that the top coat covers at least 60% of the length of the bottom wash coat layer, and the top wash coat layer is coated over 60-100% of the axial length of the substrate from either the inlet axial end or the outlet axial end of the substrate.

[0023] In another exemplary embodiment, the exhaust gas purification catalyst article is A bottom wash coat layer comprising palladium impregnated on a carrier selected from oxygen storage components, alumina components, and combinations thereof, and coated over 60-100% of the length of the substrate from the inlet axial end to the outlet axial end, A top wash coat layer comprising a top wash coat layer, the top coat being impregnated on a carrier selected from an oxygen storage component, an alumina component, and a combination thereof, so as to cover at least 60% of the length of the bottom wash coat layer, and coating 60-100% of the axial length of the substrate from either the inlet or outlet axial end of the substrate, and comprising: At least a portion of the top wash coat layer comprises a first portion and a second portion, the first portion starting from the inlet axial end of the substrate and comprising palladium or platinum optionally supported on a carrier selected from an oxygen storage component, an alumina component, and combinations thereof, wherein the concentration of palladium or platinum in the first portion is 2 to 100 times higher than the concentration of palladium or platinum in the second portion. The first portion constitutes 5-50% of the substrate volume and exhibits a three-dimensional axial and / or radial zone arrangement starting from the inlet axial end or the outlet axial end of the substrate, or both. If the amount of platinum group metal impregnation in the first portion is determined axially from the first end of the first portion to the second end of the first portion, then 10 to 1000 g / ft 3 That is the case.

[0024] In one embodiment, the bottom wash coat layer contains at least one alkaline earth metal oxide, including barium oxide, strontium oxide, or any combination thereof, in an amount of 1.0 to 20% by weight, based on the total weight of the top layer.

[0025] References to “monolithic substrate” or “honeycomb substrate” mean a single structure that is homogeneous and continuous from inlet to outlet. As used herein, the term “washcoat” has its usual meaning in the art of a thin adhesive coating of a catalyst or other material applied to a substrate material that is sufficiently porous to allow the passage of a gas stream to be treated, such as a honeycomb-type carrier member. A washcoat is formed by preparing a slurry containing a specific solid content (e.g., 15–60 wt%) of particles in a liquid vehicle, then coating this onto a substrate and drying it to provide a washcoat layer.

[0026] As used herein and as described in Heck, Ronald, and Farrauto, Robert, Catalytic Air Pollution Control, New York: Wiley-Interscience, 2002, pp. 18-19, a washcoat layer comprises compositionally distinct layers of material disposed on the surface of a monolithic substrate or an underlying washcoat layer. In one embodiment, the substrate contains one or more washcoat layers, each washcoat layer being different in some way (for example, in its physical properties such as particle size or crystallite phase) and / or having different chemical catalytic functions.

[0027] A catalyst article may be "unused," meaning it is new and has not been exposed to any heat or thermal stress for an extended period. "Unused" may also mean that the catalyst has been recently prepared and has not been exposed to any exhaust gas or high temperatures. Similarly, an "aged" catalyst article is not new and has been exposed to exhaust gas and high temperatures (i.e., above 500°C) for an extended period (i.e., more than 3 hours).

[0028] According to one or more embodiments, the substrate of the catalyst article of the currently claimed invention can be constructed from any material typically used to prepare automotive catalysts, and typically includes a ceramic or metal monolithic honeycomb structure. In one embodiment, the substrate is a ceramic substrate, a metal substrate, a ceramic foam substrate, a polymer foam substrate, or a woven fiber substrate.

[0029] The substrate typically provides a plurality of wall surfaces to which a wash coat containing the catalyst composition described herein is applied and adhered, thereby acting as a carrier for the catalyst composition.

[0030] Exemplary metal substrates include heat-resistant metals and metal alloys such as titanium and stainless steel, as well as other alloys in which iron is a substantial or major component. Such alloys may contain one or more of nickel, chromium, and / or aluminum, and the total amount of these metals may, advantageously, contain at least 15 wt% of the alloy, e.g., 10–25 wt% chromium, 3–8 wt% aluminum, and up to 20 wt% nickel. The alloys may also contain small or trace amounts of one or more metals, such as manganese, copper, vanadium, and titanium. The surface of the metal substrate may be oxidized at high temperatures, e.g., above 1000°C, to form an oxide layer on the substrate surface, improving the corrosion resistance of the alloy and facilitating the adhesion of the wash coat layer to the metal surface.

[0031] Examples of suitable ceramic materials used in constructing the substrate include any suitable refractory material, such as cordierite, mullite, cordierite-alumina, silicon nitride, zircon mullite, spodumene, alumina-silica-magnesia, zircon silicate, sillimanite, magnesium silicate, zircon, petalite, alumina, and aluminosilicate.

[0032] Any suitable substrate can be used, such as a monolithic flow-through substrate having multiple fine, parallel gas channels extending from the inlet to the outlet surface of the substrate, so that the passage is open to the fluid flow. The passage, which is essentially a straight path from inlet to outlet, is defined by walls on which the catalyst material is coated as a wash coat, so that the gas flowing through the passage comes into contact with the catalyst material. The channels in a monolithic substrate are thin-walled channels that can be of any suitable cross-sectional shape, such as trapezoidal, rectangular, square, sinusoidal, hexagonal, elliptical, and circular. Such structures contain about 60 to about 1200 or more gas inlet openings (i.e., "cells") (cpsi) per square inch of cross-section, more commonly about 300 to 900 cpsi. The wall thickness of the flow-through substrate can vary, with a typical range being 0.002 to 0.1 inches. Typical commercially available flow-through substrates are cordierite substrates with 400 cpsi and a wall thickness of 6 mil, or 600 cpsi and a wall thickness of 4.0 mil. However, it will be understood that the present invention is not limited to a particular type, material, or geometric shape of substrate. In an alternative embodiment, the substrate may be a wall-flow substrate in which each passage is closed by a non-porous plug at one end of the substrate body, and the alternating passages are closed at the opposite end faces. This requires the gas flow to pass through the porous walls of the wall-flow substrate to reach the outlet. Such monolithic substrates may contain up to about 700 or more cpsi, such as about 100 to 400 cpsi, more typically about 200 to about 300 cpsi. The cross-sectional shape of the cells may vary as described above. Wall-flow substrates typically have a wall thickness of 0.002 to 0.1 inches. Typical commercially available wall-flow substrates are constructed from porous cordierite, examples of which have 200 cpsi and a wall thickness of 10 mil, or 300 cpsi with a wall thickness of 8 mil, and a wall porosity of 45 to 65%. Other ceramic materials such as aluminum titanate, silicon carbide, and silicon nitride are also used as wall flow filter substrates. However, it should be understood that the present invention is not limited to any particular type, material, or shape of substrate.It should be noted that, when the substrate is a wall-flow substrate, the catalyst composition may not only be placed on the surface of the wall but may also penetrate into the pore structure of the porous wall (i.e., partially or completely block the pore openings). In one embodiment, the substrate has a flow-through ceramic honeycomb structure, a wall-flow ceramic honeycomb structure, or a metal honeycomb structure.

[0033] As used herein, the term “flow” broadly refers to any combination of flowing gases that may contain solid or liquid particulate matter.

[0034] As used herein, the terms “upstream” and “downstream” refer to the relative directions corresponding to the flow of engine exhaust gases from the engine to the tailpipe, with the engine located upstream and the tailpipe and any contaminant mitigation items, such as filters and catalysts, located downstream of the engine.

[0035] Figures 4A and 4B illustrate an exemplary substrate 2 in the form of a flow-through substrate coated with the wash-coat composition described herein. Referring to Figure 4A, the exemplary substrate 2 has a cylindrical shape and has a cylindrical outer surface 4, an upstream end surface 6, and a corresponding downstream end surface 8 identical to end surface 6. The substrate 2 has a plurality of fine, parallel gas channels 10 formed therein. As seen in Figure 4B, the channels 10 are formed by walls 12 and extend through the substrate 2 from the upstream end surface 6 to the downstream end surface 8, and the passages 10 are unobstructed, allowing a fluid, such as a gas flow, to flow longitudinally through the substrate 2 via its gas channels 10. As more readily seen in Figure 5, the walls 12 are dimensioned and constructed such that the gas channels 10 have a substantially regular polygonal shape. As shown, the wash-coat composition can be applied in a plurality of distinct layers as needed. In the exemplary embodiment, the wash coat consists of a separate first wash coat layer 14 adhered to the wall 12 of the substrate member and a separate second wash coat layer 16 coated on top of the first wash coat layer 14. In one embodiment, the currently claimed invention is also carried out with two or more (e.g., three or four) wash coat layers and is not limited to the exemplary two-layer embodiment.

[0036] Figure 5 illustrates an exemplary substrate 2 of a wall flow filter substrate coated with the washcoat composition described herein. As seen in Figure 5, the exemplary substrate 2 has a plurality of passages 52. The passages are tubularly enclosed by the inner wall 53 of the filter substrate. The substrate has an inlet end 54 and an outlet end 56. The alternating passages are blocked by inlet plugs 58 at the inlet end and by outlet plugs 60 at the outlet end, forming a checkerboard pattern that is reversed at the inlet 54 and outlet 56. The gas flow 62 enters through the unblocked channel inlet 64, is stopped by the outlet plugs 60, and diffuses to the outlet side 66 through the (porous) channel wall 53. The gas cannot pass back to the inlet side of the wall due to the inlet plugs 58. The porous wall flow filter used in the present invention has catalytic activity on or within the walls of the element having or containing one or more catalytic materials. The catalyst material may be present only on the inlet side of the element wall, only on the outlet side, on both the inlet and outlet sides, or the wall itself may be composed entirely or partially of the catalyst material. The present invention includes the use of one or more catalyst material layers in the inlet and / or outlet walls of an element.

[0037] In another embodiment, a process for preparing an exhaust gas purification catalyst article is provided, the process is: i) Obtain a slurry containing an optional platinum group metal impregnated in at least one carrier, and coat the substrate with the slurry over a length of 60-100% of the substrate length from the inlet axial end to the outlet axial end to obtain a bottom wash coat layer. ii) Coating at least a portion of the bottom wash coat layer starting from the inlet axial end or the outlet axial end of the substrate with a sprayed platinum-based metal precursor solution using a nozzle spray or an apparatus including a nozzle spray to create a radial zone arrangement starting from the three-dimensional axial end and / or the inlet axial end or the outlet end, and then drying at a temperature of about 100-140°C to calcify and obtain concentrated zones, iii) A process comprising: preparing a top wash coat coated to 60-100% of the length of the substrate from either the inlet axial end or the outlet axial end of the substrate such that the top coat covers at least 60% of the length of the bottom wash coat layer; obtaining a slurry containing a platinum group metal impregnated on at least one carrier; and coating the bottom wash coat over at least 60% of its length.

[0038] In one embodiment, a process for preparing an exhaust gas purification catalyst article, i) preparing a bottom wash coat layer coated over 60-100% of the length of the substrate from the inlet axial end to the outlet axial end, and obtaining a slurry optionally containing a platinum group metal impregnated in at least one carrier, and coating the entire length of the substrate with the slurry, ii) Prepare a top wash coat coated from either the inlet axial end or the outlet axial end of the substrate to a length of 60-100% of the substrate such that the top coat covers at least 60% of the length of the bottom wash coat layer, obtain a slurry containing a platinum group metal impregnated on at least one carrier, and coat the bottom wash coat with the slurry over a length of at least 60%. iii) A process comprising coating a portion of the top wash coat layer, starting at the inlet axial end or the outlet end of the substrate, with a sprayed platinum-based metal precursor solution using a nozzle spray or apparatus including a nozzle spray to create a three-dimensional axial and / or radial zone arrangement starting from the inlet axial end or the outlet end, and then drying at a temperature of about 100-140°C to calcify and obtain concentrated zones.

[0039] Unlike prior art, the process according to the currently claimed invention is performed without substrate masking to control the PGM deposition pattern. It has been found that the deposition of PGM onto the substrate by spraying and atomizing does not result in a measurable additional increase in the back pressure of the catalyst article, which consists of the substrate and the wash coat.

[0040] The step of preparing the slurry includes techniques selected from initial wet impregnation, initial wet co-impregnation, and post-addition.

[0041] Initial wet impregnation techniques, also known as capillary impregnation or dry impregnation, are commonly used in the synthesis of heterogeneous materials, i.e., catalysts. Typically, an active metal precursor is dissolved in an aqueous or organic solution, and then the metal-containing solution is added to a catalyst support, which contains the same pore volume as the volume of the added solution. The solution is drawn into the pores of the support by capillary action. If the added solution exceeds the pore volume of the support, the solution transport changes from a capillary process to a much slower diffusion process. The catalyst is dried and calcined to remove volatile components in the solution and deposit the metal on the surface of the catalyst support. The concentration profile of the impregnated material depends on the mass transport conditions in the pores during impregnation and drying. Multiple active metal precursors may be co-impregnated into the catalyst support after appropriate dilution. Alternatively, the active metal precursor is introduced into the slurry via post-addition under stirring during the slurry preparation process.

[0042] The carrier particles are typically dry enough to absorb substantially all of the solution and form a wet solid. Typically, aqueous solutions of water-soluble compounds or complexes of the active metal are used, such as rhodium chloride, rhodium nitrate, rhodium acetate, or combinations thereof (when rhodium is the active metal), and palladium nitrate, palladium tetraamine, palladium acetate, or combinations thereof (when palladium is the active metal). After treatment of the carrier particles with the active metal solution, the particles are dried by heat treatment at a high temperature (e.g., 100-150°C) for a certain period (e.g., 1-3 hours), and then calcined to convert the active metal into a more catalytically active form. An exemplary calcination process involves heat treatment in air at a temperature of about 400-550°C for 10 minutes to 3 hours. If necessary, the above process can be repeated by impregnation to reach the desired level of active metal impregnation.

[0043] The catalyst compositions described above are typically prepared in the form of catalyst particles as described above. These catalyst particles are mixed with water to form a slurry for coating catalyst substrates such as honeycomb substrates. In addition to catalyst particles, the slurry may optionally contain binders in the form of alumina, silica, zirconium acetate, colloidal zirconia, or zirconium hydroxide, associative thickeners, and / or surfactants (including anionic, cationic, nonionic, or amphoteric surfactants). Other exemplary binders include boehmite, gamma-alumina, or delta / theta-alumina, as well as silica sol. If present, the binder is typically used in an amount of about 1.0–5.0% by weight of the total washcoat impregnation. Acidic or basic species are added to the slurry to adjust the pH. For example, in some embodiments, the pH of the slurry is adjusted by adding ammonium hydroxide, aqueous nitric acid solution, or acetic acid. The typical pH range of the slurry is about 3.0–12.

[0044] The slurry may be pulverized to reduce the particle size and to promote mixing of the particles. Pulverization can be achieved with a ball mill, a continuous mill, or other similar equipment, and the solids content of the slurry can be, for example, about 20 to 60 wt%, more specifically, about 20 to 40 wt%. In one embodiment, the pulverized slurry has a D 90 particle size characterized by a D 90 which is determined using a dedicated particle size analyzer. The equipment used in this example measures the particle size of a small amount of slurry using laser diffraction. Typically, the D 90 in microns means that 90% of the number of particles have a diameter smaller than the quoted value.

[0045] Any washcoat technique known in the art is used to coat the slurry onto the catalyst substrate. In one embodiment, the catalyst substrate is immersed one or more times in the slurry or coated with the slurry. Thereafter, the coated substrate is dried at a high temperature (e.g., 100 to 150 °C) for a certain period (e.g., 10 minutes to 3 hours), and then calcined by heating at, for example, 400 to 700 °C, typically for about 10 minutes to about 3 hours. After drying and calcination, the final washcoat coating layer is considered to be essentially solvent-free. After calcination, the amount of catalyst deposition obtained by the above washcoat technique can be determined by calculating the difference between the coated weight and the uncoated weight of the substrate. As will be apparent to those skilled in the art, the amount of catalyst deposition can be adjusted by changing the rheology of the slurry. In addition, the coating / drying / calcination process for generating the washcoat can be repeated as necessary to build the coating to the desired deposition level or thickness, i.e., two or more washcoats may be applied.

[0046] In certain embodiments, the coated substrate is aged by heat treatment of the coated substrate. In one embodiment, aging is carried out in an environment of 10 vol% moisture at a temperature of about 850°C to about 1050°C for 50 to 75 hours with alternating hydrocarbon / air supply. Thus, in certain embodiments, an aged catalyst article is provided. In certain embodiments, particularly effective materials include metal oxide-based supports (including, but not limited to, substantially 100% ceria supports) that maintain a high percentage (e.g., about 95 to 100%) of their pore volume during aging (e.g., aging at about 850°C to about 1050°C with 10 vol% water and alternating hydrocarbon / air supply for 50 to 75 hours).

[0047] The currently claimed invention also provides an apparatus for producing an exhaust gas purification catalyst article, which provides a three-dimensional axial and / or radial zone arrangement, the apparatus comprising: a PGM precursor solution storage unit; a dosing unit for the PGM precursor solution; at least one PGM precursor solution supply pipe connected to the dosing unit; a spray nozzle connected to the dosing unit via a second supply pipe; an optional control arm device connected to the spray nozzle connected to an air supply means, the control arm device being adapted to enable 3D positioning of the nozzle with respect to the substrate surface; an optional additional air supply or bypass means; an optional vacuum function, the apparatus being adapted to spray the PGM precursor solution and produce a three-dimensional axial and / or radial zone arrangement including a geometric shape starting from the inlet or outlet axial end of the substrate. The PGM concentration zone is deposited on a wash-coated substrate using the apparatus described herein, which uses a nozzle to spray and disperse the PGM-containing solution onto a blank or previously wash-coated substrate. The axial and radial shapes of the PGM concentration zones are controlled by the nozzle shape and solution supply rate, and by the combination of the solution supply rate and supply air pressure. The coating profile of the substrate is further controlled by adjusting the movement of the nozzle in three-dimensional space above the surface of the substrate to be coated. The substrate is placed in the coating cell so that the surface to be coated faces the coating nozzle. The unit is then programmed so that a desired amount of PGM precursor is deposited through the nozzle. Coating then begins with a control arm moving at a predetermined speed in three-dimensional position relative to the surface of the substrate while the sprayed PGM precursor solution is deposited onto the substrate. The PGM precursor injection rate and supply air pressure are set to obtain the desired deposition rate and penetration length. Spray deposition can be further assisted, if necessary, using supply air or vacuum functions provided by the device so that the sprayed PGM solution deposited by the nozzle can be guided onto the substrate as needed. Once the process is complete, the substrate is removed and the next substrate is loaded into the cell.PGM control is performed by measuring the weight of the substrate before and after coating. Optionally, weighing can be performed during spray coating.

[0048] In another embodiment, an exhaust system for an internal combustion engine is provided, comprising an exhaust purification catalyst article according to the currently claimed invention.

[0049] According to another aspect of the currently claimed invention, a method is provided for treating a gaseous exhaust flow containing hydrocarbons, carbon monoxide, and nitrogen oxides, the method comprising bringing the exhaust flow into contact with a catalyst article or exhaust system according to the currently claimed invention.

[0050] In another aspect, the currently claimed invention provides a method for reducing the levels of hydrocarbons, carbon monoxide, and nitrogen oxides in a gaseous exhaust stream, comprising bringing the gaseous exhaust stream into contact with a catalyst article or exhaust system according to the currently claimed invention to reduce the levels of hydrocarbons, carbon monoxide, and nitrogen oxides in the exhaust gas.

[0051] In another embodiment, the currently claimed invention also provides the use of the catalytic system of the currently claimed invention for purifying gaseous exhaust streams containing hydrocarbons, carbon monoxide, and nitrogen oxides.

[0052] The present invention provides the following embodiments.

[0053] 1. Exhaust gas purification catalyst article, A base material having an inlet axial end and an outlet axial end, A bottom wash coat layer is coated over 60-100% of the length of the substrate from the inlet axial end to the outlet axial end, A top wash coat layer comprising a top wash coat layer that covers at least 60% of the length of the bottom wash coat layer, and is coated from the inlet axial end or outlet axial end of the substrate, or both ends, to a length of 60-100% of the substrate, At least a portion of the top wash coat layer and / or bottom wash coat layer comprises a first portion and a second portion, wherein the first portion begins at the inlet axial end or the outlet axial end of the substrate and exhibits a platinum group metal concentration 2 to 100 times higher than the platinum group metal concentration in the second portion. The first portion constitutes 5-50% of the substrate volume and exhibits a three-dimensional axial and / or radial zone arrangement starting from the inlet axial end or the outlet axial end of the substrate, or both. If the amount of platinum group metal impregnation in the first portion is determined axially from the first end of the first portion to the second end of the first portion, then 10 to 1000 g / ft 3 It is an exhaust gas purification catalyst article.

[0054] 2. The exhaust gas purification catalyst article according to Embodiment 1 has a geometric shape in which a three-dimensional axial and / or radial zone arrangement starting from the inlet axial end or the outlet axial end, or both, each has a base that covers 20-100% of the substrate surface from the substrate end and has a volume of 5-50% of the substrate volume.

[0055] 3. An exhaust gas purification catalyst article according to Embodiment 1 or 2, wherein the three-dimensional axial and / or radial zone arrangement includes geometric shapes selected from cones, tapered cones, asymmetric cones, round cylinders, elliptical cylinders, polygonal cylinders, round pyramids, elliptical pyramids, polygonal pyramids, cubes, parabolic, semi-elliptical, hemispheres, polygonal prisms, parallelepipeds, rhombohedrons, polyhedra, and hyperbolas.

[0056] 4. An exhaust gas purification catalyst article according to any one of embodiments 1 to 3, wherein a three-dimensional axial and / or radial zone arrangement having a geometric shape, starting from the inlet axial end or the outlet end, or both, is produced by coating the substrate in the axial and radial directions, or simultaneously in the axial and radial directions, using a spray nozzle or a device equipped with a spray nozzle.

[0057] 5. An exhaust gas purification catalyst article according to any one of Embodiments 1 to 4, wherein the first portion is a concentration zone formed by coating at least a portion of a top wash coat layer and / or bottom wash coat layer, in which platinum group metals are optionally pre-impregnated over the entire length of the substrate, with an additional platinum group metal solution deposited in a sprayed manner.

[0058] 6. The catalyst article is one of Embodiments 1 to 5, wherein the platinum group metal is selected from platinum, palladium, rhodium, and combinations thereof.

[0059] 7. An exhaust gas purification catalyst article according to any one of Embodiments 1 to 6, wherein a platinum group metal is supported on a carrier selected from an oxygen storage component, an alumina component, a ceria component, a zirconia component, and combinations thereof.

[0060] 8. A catalyst article according to any one of Embodiments 1 to 7, wherein the first portion has an axial length in the range of 5 to 50% of the substrate from the inlet end or outlet end and covers 20 to 100% of the inlet or outlet surface of the substrate, such that the total volume of the formed geometric shape is 5 to 50% of the substrate volume.

[0061] 9. The catalyst article according to any one of Embodiments 1 to 8, wherein, as determined by electron probe microanalysis (EPMA) line scan from the top layer of the first portion of the concentrated washcoat layer to the substrate, more than 50% of the platinum group metals in the first portion are present in the top third of the first portion.

[0062] 10. A catalyst article according to any one of Embodiments 1 to 9, wherein, as determined by electron probe microanalysis (EPMA) line scan from the top layer of the first portion to the substrate, at least 40-100% of the platinum group metals in the first portion are distributed through the wash coat within the first portion with a gradient of 50% or less.

[0063] 11. The catalyst article according to any one of Embodiments 1 to 10 is present in the uppermost 1 / 3 of the first portion, when 50% to 95% of the platinum group metals in the first portion are determined by an electron probe microanalysis (EPMA) line scan from the uppermost layer of the first portion of the concentrated washcoat layer to the substrate.

[0064] 12. The first part is a catalyst article according to any one of Embodiments 1 to 11, comprising palladium.

[0065] 13. The first part is a catalyst article according to any one of Embodiments 1 to 12, comprising platinum.

[0066] 14. The first part is a catalyst article according to any one of Embodiments 1 to 13, comprising rhodium.

[0067] 15. The item is A bottom wash coat layer comprising palladium or platinum deposited on a carrier selected from an oxygen storage component, an alumina component, and a combination thereof, and coated over a length of 60 to 100 of the substrate from the inlet axial end to the outlet axial end, At least a portion of the bottom wash coat layer includes a first portion and a second portion, The first portion comprises palladium or platinum, optionally supported on a carrier selected from an oxygen storage component, an alumina component, and combinations thereof, beginning at the inlet axial end or the outlet axial end of the substrate. The concentration of palladium or platinum in the first part is 2 to 100 times higher than the concentration of palladium or platinum in the second part. The first portion constitutes 5-50% of the substrate volume and exhibits a three-dimensional axial and / or radial zone arrangement starting from the inlet axial end or the outlet axial end of the substrate, or both. If the amount of platinum group metal impregnation in the first portion is determined axially from the first end of the first portion to the second end of the first portion, then 10 to 1000 g / ft 3 The bottom wash coat layer, A catalyst article according to any one of embodiments 1 to 14, comprising a top wash coat layer, the top coat comprising rhodium, platinum, or a combination thereof, impregnated on a carrier selected from an oxygen storage component, an alumina component, and a combination thereof, such that the top coat covers at least 60% of the length of the bottom wash coat layer, and coated from either the inlet axial end or the outlet axial end of the substrate to 60-100% of the axial length of the substrate.

[0068] 16. The item is A bottom wash coat layer comprising palladium impregnated on a carrier selected from oxygen storage components, alumina components, and combinations thereof, and coated over 60-100% of the length of the substrate from the inlet axial end to the outlet axial end, A top wash coat layer comprising a top wash coat layer, the top coat being impregnated on a carrier selected from an oxygen storage component, an alumina component, and a combination thereof, so as to cover at least 60% of the length of the bottom wash coat layer, and coating 60-100% of the axial length of the substrate from either the inlet or outlet axial end of the substrate, and comprising: At least a portion of the top wash coat layer comprises a first portion and a second portion, the first portion starting from the inlet axial end of the substrate and comprising palladium or platinum optionally supported on a carrier selected from an oxygen storage component, an alumina component, and combinations thereof, wherein the concentration of palladium or platinum in the first portion is 2 to 100 times higher than the concentration of palladium or platinum in the second portion. The first portion constitutes 5-50% of the substrate volume and exhibits a three-dimensional axial and / or radial zone arrangement starting from the inlet axial end or the outlet axial end of the substrate, or both. If the amount of platinum group metal impregnation in the first portion is determined axially from the first end of the first portion to the second end of the first portion, then 10 to 1000 g / ft 3 This is a catalyst article described in any one of Embodiments 1 to 15.

[0069] 17. The catalyst article according to any one of Embodiments 1 to 16, wherein the first part comprises palladium, and the amount of palladium in the first part is 30 to 100% by weight of the total palladium present in the catalyst article.

[0070] 18. An exhaust gas purification catalyst article according to any one of Embodiments 1 to 17, wherein the first part comprises platinum, and the amount of platinum in the first part is 30 to 100% by weight of the total platinum present in the catalyst article.

[0071] 19. A catalyst article according to any one of Embodiments 1 to 18, wherein the weight ratio of the platinum group metal of the first part to the platinum group metal of the second part is 4.0 to 50.

[0072] 20. A catalyst article according to any one of Embodiments 1 to 19, wherein the alumina component comprises alumina, lantana-alumina, ceria-alumina, ceria-zirconia-alumina, zirconia-alumina, lantana-zirconia-alumina, barrier-alumina, barrier-lantana-alumina, barrier-lantana-neodymia-alumina, or a combination thereof, and the oxygen storage component comprises ceria-zirconia, ceria-zirconia-lantana, ceria-zirconia-yttria, ceria-zirconia-lantana-yttria, ceria-zirconia-neodymia, ceria-zirconia-lantana-neodymia, ceria-zirconia-lantana-neodymia, ceria-zirconia-lantana-neodymia-praseodymia, or any combination thereof, and the zirconia component comprises lantana-zirconia and barium-zirconia.

[0073] 21. The catalyst article according to any one of Embodiments 1 to 20, wherein the bottom wash coat layer contains at least one alkaline earth metal oxide, including barium oxide, strontium oxide, or any combination thereof, in an amount of 1.0 to 20% by weight, based on the total weight of the top layer.

[0074] 22. The catalyst article according to any one of Embodiments 1 to 21, wherein the base material is a ceramic base material, a metal base material, a ceramic foam base material, a polymer foam base material, or a woven fiber base material.

[0075] 23. A process for preparing exhaust gas purification catalyst articles, wherein the process is: i. Obtain a slurry containing an optional platinum group metal impregnated in at least one carrier, and coat the substrate with the slurry over a length of 60-100% of the substrate length from the inlet axial end to the outlet axial end to obtain a bottom wash coat layer. ii. Coating at least a portion of the bottom wash coat layer starting from the inlet axial end or the outlet axial end of the substrate with a sprayed platinum-based metal precursor solution using a nozzle spray or an apparatus including a nozzle spray to create a radial zone arrangement starting from the three-dimensional axial end and / or the inlet axial end or the outlet end, and then drying at a temperature of about 100-140°C to calcify and obtain concentrated zones, iii. A process comprising: preparing a top wash coat coated to 60-100% of the length of the substrate from either the inlet axial end or the outlet axial end of the substrate such that the top coat covers at least 60% of the length of the bottom wash coat layer; obtaining a slurry containing a platinum group metal impregnated on at least one carrier; and coating the bottom wash coat over at least 60% of its length.

[0076] 24. A process for preparing exhaust gas purification catalyst articles, i. The process includes preparing a bottom wash coat layer coated over 60-100% of the length of the substrate from the inlet axial end to the outlet axial end, obtaining a slurry optionally containing a platinum group metal impregnated in at least one carrier, and coating the entire length of the substrate with the slurry. ii. The method includes preparing a top wash coat coated from either the inlet axial end or the outlet axial end of the substrate to 60-100% of the length of the substrate such that the top coat covers at least 60% of the length of the bottom wash coat layer, obtaining a slurry containing platinum group metals impregnated on at least one carrier, and coating the bottom wash coat over at least 60% of its length, iii. A process comprising coating a portion of the top wash coat layer, starting at the inlet axial end or the outlet end of the substrate, with a sprayed platinum-based metal precursor solution using a nozzle spray or apparatus including a nozzle spray to create a three-dimensional axial and / or radial zone arrangement starting from the inlet axial end or the outlet end, and then drying at a temperature of approximately 100-140°C to calcify and obtain concentrated zones.

[0077] 25. An apparatus for preparing a catalyst article according to any one of Embodiments 1 to 22, wherein the apparatus comprises a PGM precursor solution storage unit, a dosing unit for the PGM precursor solution, at least one PGM precursor solution supply pipe connected to the dosing unit, a spray nozzle connected to the dosing unit via a second supply pipe, an optional control arm device connected to the spray nozzle connected to an air supply means, the control arm device being adapted to enable 3D positioning of the nozzle with respect to the substrate surface, an optional additional air supply or bypass means, and an optional vacuum function, wherein the apparatus is adapted to spray the PGM precursor solution and produce a three-dimensional axial and / or radial zone arrangement including a geometric shape starting from the inlet or outlet axial end of the substrate.

[0078] 26. An exhaust system for an internal combustion engine, wherein the system comprises an exhaust catalytic converter article described in any one of Embodiments 1 to 22.

[0079] 27. A method for treating a gaseous exhaust flow containing hydrocarbons, carbon monoxide, and nitrogen oxides, comprising contacting the exhaust flow with an exhaust purification catalyst article described in any one of Embodiments 1 to 22, or with an exhaust system described in Embodiment 26.

[0080] 28. A method for reducing the levels of hydrocarbons, carbon monoxide, and nitrogen oxides in a gaseous exhaust flow, the method comprising bringing the gaseous exhaust flow into contact with an exhaust purification catalyst article described in any one of Embodiments 1 to 22, or with an exhaust system described in Embodiment 26, thereby reducing the levels of hydrocarbons, carbon monoxide, and nitrogen oxides in the exhaust gas.

[0081] 29. Use of an exhaust gas purification catalyst article according to any one of Embodiments 1 to 22 for purifying a gaseous exhaust flow containing hydrocarbons, carbon monoxide, and nitrogen oxides. [Examples]

[0082] The embodiments of the invention currently claimed are further illustrated in full by the following embodiments, which are provided to illustrate certain aspects of the invention and should not be construed as limiting them.

[0083] A catalyst of the present invention, having concentration zone formation by PGM spraying and subsequent deposition using a nozzle, is schematically shown in Figure 1, where 10 is the PGM supply, 12 is the nozzle, 14 is the sprayed PGM, 16 is the radial zone, 18 is the axial zone, and 20 is the substrate. Exemplifying demonstrated zone patterns or catalyst structures fabricated using axial / radial coatings are shown in Figure 2. These patterns, i.e., catalyst A (reference catalyst A: 0 / 96 / 4), B (catalyst B: 0 / 76.8 / 4), and C (catalyst C: 0 / 76.8 / 4), are shown only as examples and are not considered to constrain other possible concentration zone shapes. There are several important parameters that can be optimized to achieve the desired concentration zone shape and location, including, but are not limited to, 1) Type and concentration of PGM precursor, 2) Nozzle shape and opening, 3) Supply air pressure, 4) Supply rate and pressure of PGM solution, 5) The orientation of the nozzle in space relative to the surface of the coated substrate, 6) Deposition rate and duration, 7) Includes the base material and, if present, the underlying wash coat type.

[0084] Table 1 shows the deviation (%) from the target amount of PGM impregnation onto the catalyst using sprayed PGM precursor deposited via a nozzle for four exemplary sequentially prepared components. [Table 1]

[0085] One of the key advantages of the approach schematically presented in Figure 1 is that it does not require a mask or any mechanical influencing factors to achieve the desired shape, location, and PGM concentration of the enrichment zone. Furthermore, this method enables high-precision PGM deposition. The precision of PGM deposition is illustrated in Table 1, which shows the results of Pd deposition on coated substrates. With this method, the amount of PGM impregnated can be deviated strictly (<1%) from the target.

[0086] Example 1: Preparation of CC1 reference catalyst A Reference catalyst A is 100 g / ft 3 This is a Pd / Rh catalyst article having a PGM impregnation amount of (Pt / Pd / Rh = 0 / 96 / 4). Catalyst A is a two-layer wash-coat architecture coated on a cylindrical monolithic cordierite substrate having dimensions of 4.66 inches in diameter and 4.4 inches in length, a cell density of 900 cpsi, and a wall thickness of 2.5 mils.

[0087] Preparation of the bottom coat: In the form of a palladium precursor solution, 48 g / ft 3 Pd (50% by weight of total Pd) is impregnated onto refractory alumina, and in the form of a palladium precursor solution, 48 g / ft 3Pd (50% by weight of total Pd) was impregnated onto a stabilized ceria-zirconia composite material containing approximately 40% by weight of ceria. A slurry containing approximately 35.2% by weight of refractory Al2O3, 49.6% by weight of stabilized ceria-zirconia composite material, barium acetate yielding 11.6% by weight of BaO, zirconium acetate yielding 1.9% by weight of ZrO2, and 1.7% by weight of Pd was coated onto the substrate. After firing in air at 550°C for 1 hour, the amount of wash coat impregnated into the bottom coat was approximately 2.59 g / in. 3 That was the case.

[0088] Preparation of the topcoat: 4 g / ft of rhodium precursor solution. 3 Rh (100% by weight of total Rh) was impregnated onto refractory alumina. A slurry mixture containing approximately 84.8% by weight of refractory Al2O3, 15.0% by weight of ceria-zirconia composite material with approximately 50% by weight of ceria, and 0.23% by weight of Rh was coated onto the bottom coat. After firing in air at 550°C for 1 hour, the amount of wash coat impregnated into the top coat was approximately 1.00 g / in. 3 The reference Pd / Rh catalyst article is illustrated in Figure 2.

[0089] Example 2: Preparation of CC1 Invention Catalyst B Inventive catalyst B is a Pd / Rh catalyst article with a PGM impregnation amount of 80.8 g / ft3 (Pt / Pd / Rh = 0 / 76.8 / 4). Catalyst B includes a washcoat architecture comprising a bottom coat, an additional PGM concentration zone on the catalyst inlet side, and a topcoat coated on a cylindrical monolithic cordierite substrate having dimensions of 4.66 inches in diameter and 4.4 inches in length, a cell density of 900 cpsi, and a wall thickness of 2.5 mils.

[0090] Preparation of the bottom coat: Palladium precursor solution, 24 g / ft 3 Pd (31.25% by weight of total Pd) is impregnated onto refractory alumina, and in the form of a palladium precursor solution, 24 g / ft 3Pd (31.25 wt% of total Pd) was impregnated onto a stabilized ceria-zirconia composite material containing approximately 40 wt% ceria. A slurry containing approximately 35.3 wt% refractory Al2O3, 50.0 wt% stabilized ceria-zirconia composite material, barium acetate yielding 11.7 wt% BaO, zirconium acetate yielding 1.9 wt% ZrO2, and 1.1 wt% Pd was coated onto the substrate. After firing in air at 550°C for 1 hour, the amount of wash coat impregnated into the bottom coat was approximately 2.57 g / in. 3 That was the case.

[0091] Adjustment of the concentration zone at the catalyst inlet: 305.7 g / ft of palladium precursor solution. 3 Pd (37.5% of total Pd) is sprayed and deposited on the inlet side of the wash-coated substrate, as schematically shown in Figure 1. This covers approximately 9.4% of the substrate volume and forms a Pd-concentrated zone with the shape schematically shown in Figure 2. After deposition of the Pd-concentrated zone, the total amount of Pd impregnated in the sample, considering the total volume of the substrate, is 76.8 g / ft. 3 (or 80% of reference catalyst A). In the subsequent step, the substrate was dried at 120°C for 30 minutes and calcined in air for 1 hour. Pd concentration into the underlying bottom coat was carried out so that the entire range of the underlying wash coat was concentrated with a controlled gradient, and in the case of catalyst B, the gradient was limited to 50% or less between the highest and lowest Pd concentration values ​​in the coating determined from the EPMA line profile.

[0092] Preparation of the topcoat: 4 g / ft of rhodium precursor solution. 3 Rh (100% by weight of total Rh) was impregnated onto refractory alumina. A slurry mixture containing approximately 84.8% by weight of refractory Al2O3, 15.0% by weight of ceria-zirconia composite material with approximately 50% by weight of ceria, and 0.2% by weight of Rh was coated onto the bottom coat. After firing in air at 550°C for 1 hour, the amount of wash coat impregnated into the top coat was approximately 1.00 g / in. 3 Catalyst B is illustrated in Figure 2.

[0093] Example 3: Preparation of Catalyst C of the CC1 Invention The catalyst C of the present invention has a PGM impregnation amount of 80.8 g / ft 3 The catalyst article has a Pd / Rh ratio of (Pt / Pd / Rh = 0 / 76.8 / 4). Catalyst C includes a washcoat architecture consisting of a bottom coat, an additional PGM enrichment zone on the catalyst inlet side, and a topcoat coated on a cylindrical monolithic cordierite substrate having dimensions of 4.66 inches in diameter and 4.4 inches in length, a cell density of 900 cpsi, and a wall thickness of 2.5 mils.

[0094] Preparation of the bottom coat: The bottom coat was identical to the bottom coat of catalyst B.

[0095] Preparation of the concentration zone on the inlet side of the catalyst: The concentration zone was identical to that of catalyst B. The volume of the concentration zone still accounted for approximately 9.4% of the total substrate volume, but as shown in Figure 2, the zone covered the entire inlet and protruded axially from the inlet towards the outlet side of the substrate. After deposition of the Pd concentration zone, the total Pd impregnation amount of the sample was 76.8 g / ft, considering the total volume of the substrate. 3 (Or 80% of reference catalyst A)

[0096] Preparation of the topcoat: The topcoat is identical to that of catalyst B. Catalyst C is shown in Figure 2.

[0097] Example 4: Preparation of UF reference catalyst D Reference catalyst D is 3 g / ft 3 The catalyst article has a PGM impregnation ratio of (Pt / Pd / Rh=0 / 0 / 3). Catalyst J comprises a single-layer wash-coat architecture coated on a cylindrical monolithic cordierite substrate having dimensions of 4.66 inches in diameter and 4.4 inches in length, a cell density of 400 cpsi, and a wall thickness of 4 mils.

[0098] In the form of a rhodium precursor solution, 3 g / ft 3Rh (100% by weight of total Rh) was mixed with water, refractory alumina, and a stabilized ceria-zirconia composite material containing approximately 40% by weight of ceria. A slurry containing approximately 63.1% by weight of refractory Al2O3, 32.0% by weight of stabilized ceria-zirconia composite material, barium acetate yielding 1.5% by weight of BaO, zirconium acetate yielding 0.3% by weight of ZrO2, strontium acetate yielding 1.5% by weight of SrO, and 0.1% by weight of Rh was coated onto the substrate. After firing in air at 550°C for 1 hour, the amount of wash coat impregnated was approximately 2.8 g / in. 3 That was the case.

[0099] Example 5: Catalyst testing All catalysts prepared in Examples 1-4 were aged using an exothermic aging protocol with an engine set to operate so that a typical inlet temperature does not exceed approximately 940°C and a typical catalyst bed temperature does not exceed 1000°C. To simulate the typical operating conditions of a vehicle tested with the FTP-75 test protocol, the engine outgass supply composition was alternated between rich and lean. All CC1 catalysts and UF catalyst D were aged for 100 hours under the same conditions.

[0100] Exhaust performance was tested using a 2.0L turbocharged ULEV70 vehicle equipped with a CC1+UF exhaust purification system configuration, operated under the FTP-75 test protocol. Each system was tested at least four times to ensure high experimental reproducibility and data consistency.

[0101] Table 2 demonstrates the advantages of using the PGM concentration zone. [Table 2]

[0102] The catalyst of the present invention produces up to 10% more NMHC+NO compared to Pd / Rh reference catalyst A. xThe catalyst system demonstrates emission reductions of NMHC+NOx with a SULEV rating of 30 or higher under selected aging and test conditions. x The performance is achieved. Furthermore, the design-specific PGM concentration zone allows for a 20% reduction in Pd deposition without affecting vehicle emissions.

[0103] The improved catalytic activity resulting from the implementation of the proposed design architecture leads to a lower catalyst ignition temperature and lower emissions in the Bag-1 portion of the FTP-75 test. Figure 3 summarizes the THC light-off curves for catalyst A 0 / 96 / 4 and catalyst B 0 / 76.8 / 4 measured in the light-off portion of the FTP-75 test of a 2.0L turbocharged ULEV70 vehicle equipped with a CC1+UF exhaust purification system. Deposition of a PGM enrichment zone at the catalyst inlet lowers the hydrocarbon ignition temperature by approximately 25°C. The improvement in the example catalyst B is observed with approximately 30-60% conversion at catalyst bed temperatures of approximately 120-200°C. Catalyst B achieves improved light-off with approximately 20% less PGM compared to reference catalyst A.

[0104] Throughout this specification, any reference to “one embodiment,” “a particular embodiment,” “one or more embodiments,” or “embodiments” means that any particular feature, structure, material, or property described in relation to an embodiment is included in at least one embodiment of the claimed invention. Therefore, the appearance of phrases such as “in one or more embodiments,” “in a particular embodiment,” “in some embodiments,” “in one embodiment,” or “in an embodiment” in various places throughout this specification does not necessarily refer to the same embodiment of the claimed invention. Furthermore, any particular feature, structure, material, or property can be combined in any preferred manner in one or more embodiments. All of the various embodiments, aspects, and options disclosed herein can be combined in all variations, regardless of whether such feature or element is explicitly combined in the description of a particular embodiment herein. The claimed invention is intended to be read as a whole, so that, unless the context clearly indicates otherwise, any divisible feature or element of the disclosed invention is intended to be combinable in any of its various aspects and embodiments.

[0105] While the embodiments disclosed herein have been described with reference to specific embodiments, it should be understood that these embodiments are merely illustrative of the principles and uses of the currently claimed invention. It will be apparent to those skilled in the art that various modifications and changes can be made to the methods and apparatus of the currently claimed invention without departing from the spirit and scope of the currently claimed invention. Accordingly, the currently claimed invention is intended to include modifications and changes within the scope of the appended claims and their equivalents, and the embodiments described above are presented for illustrative purposes only, not limitation. All patents and publications cited herein are incorporated herein by reference with respect to the specific teachings described therein unless other incorporated statements are specifically provided.

Claims

1. An exhaust purification catalyst article, a substrate having an inlet axial end and an outlet axial end; A bottom washcoat layer coated on 60 to 100% of the length of the substrate from the inlet axial end to the outlet axial end; a top washcoat layer, the top washcoat layer being coated from the inlet axial end or the outlet axial end or both ends of the substrate over 60 to 100% of the length of the substrate so as to cover at least 60% of the length of the bottom washcoat layer; at least a portion of the top washcoat layer and / or the bottom washcoat layer comprises a first portion and a second portion, the first portion beginning at the inlet axial end of the substrate or the outlet axial end of the substrate and exhibiting a concentration of platinum group metal that is 2 to 100 times higher than a concentration of platinum group metal in the second portion; the first portion comprises 5-50% of the substrate volume and exhibits a three-dimensional axial and / or radial zone arrangement beginning at an inlet axial end or an outlet axial end or both of the substrate; In the case where the amount of the platinum group metal impregnated in the first portion is determined in the axial direction from the inlet axial end of the substrate to the outlet axial end of the substrate or from the outlet axial end of the substrate to the inlet axial end of the substrate, the amount of the platinum group metal impregnated in the first portion is 10 to 1000 g / (25.4 mm) ３ and An exhaust gas purification catalyst article, wherein a three-dimensional axial and / or radial zone arrangement of the first portion starting from the inlet axial end or the outlet axial end, or both, is a geometric shape, and the geometric shape is a cone.

2. An exhaust purification catalyst article as described in claim 1, wherein the geometric shape has a base covering 20 to 100% of the substrate surface from each substrate end, and has a volume of 5 to 50% of the substrate volume.

3. An exhaust purification catalyst article as described in claim 1 or 2, wherein the shape of the cone is selected from a tapered cone, an asymmetrical cone, a rounded pyramid, an elliptical pyramid, and a polygonal pyramid.

4. 10. The catalytic article of claim 1, wherein the platinum group metal is selected from platinum, palladium, rhodium, and combinations thereof.

5. 10. The catalytic article of claim 1, wherein the platinum group metal is supported on a support selected from an oxygen storage component, an alumina component, a ceria component, a zirconia component, and combinations thereof.

6. 2. The catalyst article of claim 1, wherein the first portion has an axial length in the range of 5-50% of the substrate from the inlet axial end or the outlet axial end and covers 20-100% of the inlet or outlet face of the substrate such that the total volume of the formed geometric shape is 5-50% of the substrate volume.

7. The catalyst article of claim 1, wherein more than 50% of the platinum group metal in the first portion is present in the top third of the first portion as determined by an electron probe microanalysis (EPMA) line scan from the top layer of the first portion to the substrate.

8. 8. The catalytic article of any one of claims 1 to 7, wherein 50% to 95% of the platinum group metal in the first portion is present in the top third of the first portion as determined by an electron probe microanalysis (EPMA) line scan from the top layer of the first portion to the substrate.

9. The catalytic article of claim 1 , wherein the first portion comprises palladium.

10. The catalytic article of claim 1 , wherein the first portion comprises platinum.

11. The catalytic article of claim 1 , wherein the first portion comprises rhodium.

12. The article, A bottom washcoat layer comprising palladium or platinum deposited on a carrier selected from an oxygen storage component, an alumina component, and combinations thereof, coated on 60-100% of the length of the substrate from the inlet axial end to the outlet axial end, At least a portion of the bottom washcoat layer includes a first portion and a second portion; the first portion beginning at the inlet axial end or the outlet axial end of the substrate comprises palladium or platinum optionally supported on a support selected from an oxygen storage component, an alumina component, and combinations thereof; the concentration of palladium or platinum in the first portion is 2 to 100 times higher than the concentration of palladium or platinum in the second portion; the first portion comprises 5-50% of the volume of the substrate and exhibits a three-dimensional axial and / or radial zone arrangement beginning at the inlet axial end or the outlet axial end, or both, of the substrate; The loading of the platinum group metal in the first portion, when determined axially from the inlet axial end of the first portion to the outlet axial end of the first portion, is 10 to 1000 g / (25.4 mm) ３ A bottom wash coat layer, 2. The catalyst article of claim 1, comprising: a top washcoat layer comprising rhodium, platinum, or a combination thereof impregnated on a support selected from an oxygen storage component, an alumina component, and combinations thereof, the top washcoat layer covering at least 60% of the length of the bottom washcoat layer, the top washcoat layer being coated from either the inlet axial end or the outlet axial end of the substrate for 60-100% of the axial length of the substrate.

13. The article, a bottom washcoat layer comprising palladium impregnated on a carrier selected from an oxygen storage component, an alumina component, and combinations thereof, coated on 60-100% of the length of the substrate from the inlet axial end to the outlet axial end; a top washcoat layer comprising rhodium, platinum, palladium, or combinations thereof impregnated on a support selected from an oxygen storage component, an alumina component, and combinations thereof, the top washcoat layer covering at least 60% of the length of the bottom washcoat layer, the top washcoat layer being coated from either the inlet or outlet axial end of the substrate for 60-100% of the axial length of the substrate; at least a portion of the top washcoat layer comprises a first portion and a second portion, the first portion beginning at an inlet axial end of the substrate and comprising palladium or platinum optionally supported on a support selected from an oxygen storage component, an alumina component, and combinations thereof, the concentration of palladium or platinum in the first portion being 2 to 100 times higher than the concentration of palladium or platinum in the second portion; the first portion comprises 5-50% of the volume of the substrate and exhibits a three-dimensional axial and / or radial zone arrangement beginning at the inlet axial end or the outlet axial end, or both, of the substrate; The loading of the platinum group metal in the first portion, when determined axially from the inlet axial end of the first portion to the outlet axial end of the first portion, is 10 to 1000 g / (25.4 mm) ３ 2. The catalytic article of claim 1 ,

14. 14. The catalytic article of claim 12 or 13, wherein the first portion comprises palladium, and the amount of palladium in the first portion is from 30 to 100 weight percent of the total palladium present in the catalytic article.

15. 14. The catalytic article of claim 12 or 13, wherein the first portion comprises platinum, and the amount of platinum in the first portion is 30 to 100 weight percent of the total platinum present in the catalytic article.

16. Catalyst article according to any one of claims 1 to 15, wherein the weight ratio of the platinum group metal of the first portion to the platinum group metal of the second portion is from 4.0 to 50.

17. 6. The catalytic article of claim 5, wherein the alumina component comprises alumina, lanthana-alumina, ceria-alumina, ceria-zirconia-alumina, zirconia-alumina, lanthana-zirconia-alumina, baria-alumina, baria-lanthana-alumina, baria-lanthana-neodymia-alumina, or a combination thereof; the oxygen storage component comprises ceria-zirconia, ceria-zirconia-lanthana, ceria-zirconia-yttria, ceria-zirconia-lanthana-yttria, ceria-zirconia-neodymia, ceria-zirconia-praseodymia, ceria-zirconia-lanthana-neodymia, ceria-zirconia-lanthana-praseodymia, ceria-zirconia-lanthana-neodymia-praseodymia, or any combination thereof; and the zirconia component comprises lanthana-zirconia and barium zirconia.

18. 18. The catalytic article of any one of claims 1 to 17, wherein the bottom washcoat layer comprises at least one alkaline earth metal oxide comprising barium oxide, strontium oxide, or any combination thereof, in an amount of 1.0 to 20 wt%, based on a total weight of the bottom washcoat layer.

19. The catalytic article of any one of claims 1 to 18, wherein the substrate is a ceramic substrate, a metal substrate, a ceramic foam substrate, a polymeric foam substrate, or a woven fiber substrate.

20. A process for preparing an exhaust gas purification catalyst article according to claim 1, said process comprising: i. obtaining a slurry optionally comprising a platinum group metal impregnated on at least one carrier, and coating said slurry on 60-100% of the length of said substrate from an inlet axial end to an outlet axial end of said substrate to obtain a bottom washcoat layer; ii. Coating at least a portion of the bottom washcoat layer starting at the inlet axial end or outlet axial end of the substrate with an atomized platinum-based metal precursor solution using a nozzle spray or an apparatus including a nozzle spray to create a three-dimensional axial and / or radial zone arrangement starting at the inlet axial end or outlet axial end, followed by drying and calcination at a temperature of 100-140° C. to obtain enrichment zones; iii. A process comprising: obtaining a top washcoat layer slurry comprising a platinum group metal impregnated on at least one carrier, coating the top washcoat layer slurry over at least 60% of the length of the bottom washcoat layer, and preparing a top washcoat layer coated from either the inlet axial end or the outlet axial end of the substrate over 60-100% of the length of the substrate such that the top washcoat layer covers at least 60% of the length of the bottom washcoat layer.

21. A process for preparing an exhaust gas purification catalyst article according to claim 1, said process comprising: i. obtaining a slurry optionally containing a platinum group metal impregnated on at least one carrier, coating the bottom washcoat layer slurry on the entire length of the substrate, and preparing a bottom washcoat layer coated on 60-100% of the length of the substrate from the inlet axial end to the outlet axial end; ii. A method for producing a top washcoat layer comprising: obtaining a top washcoat layer slurry comprising a platinum group metal impregnated on at least one carrier; coating the top washcoat layer slurry over at least 60% of the length of the bottom washcoat layer; and preparing a top washcoat layer coated from either the inlet axial end or the outlet axial end of the substrate over 60-100% of the length of the substrate such that the top washcoat layer covers at least 60% of the length of the bottom washcoat layer; iii. Coating a portion of the top washcoat layer starting at the inlet axial end or outlet end of the substrate with an atomized platinum-based metal precursor solution using a nozzle spray or an apparatus including a nozzle spray to create a three-dimensional axial and / or radial arrangement starting at the inlet axial end or outlet end, followed by drying and calcination at a temperature of 100-140° C. to obtain a concentrated zone.

22. 10. An apparatus for conditioning a catalyst article according to claim 1, comprising: a PGM precursor solution storage unit; a dosing unit for the PGM precursor solution; At least one PGM precursor solution supply line connected to the dosing unit; a spray nozzle connected to the dispensing unit via a second supply line; a control arm device connected to said spray nozzle, which is optionally connected to an air supply means, which control arm device is adapted to allow 3D positioning of said nozzle with respect to a substrate surface; an optional additional air supply or bypass means, which air supply or bypass means is optionally equipped with a vacuum function; Equipped with The apparatus is adapted to spray a PGM precursor solution to create a three-dimensional axial and / or radial zone arrangement that includes a geometric shape originating from an inlet or outlet axial end of the substrate.

23. An exhaust system for an internal combustion engine, said system comprising the engine and a catalytic article according to any one of claims 1 to 19.

24. 24. A method for treating a gaseous exhaust stream containing hydrocarbons, carbon monoxide, and nitrogen oxides, comprising contacting the exhaust stream with a catalytic article according to any one of claims 1 to 19, or an exhaust system according to claim 23.

25. 26. A method for reducing the levels of hydrocarbons, carbon monoxide, and nitrogen oxides in a gaseous exhaust stream, the method comprising contacting the gaseous exhaust stream with a catalytic article according to any one of claims 1 to 19, or an exhaust system according to claim 23, to reduce the levels of hydrocarbons, carbon monoxide, and nitrogen oxides in the gaseous exhaust stream.

26. Use of a catalytic article according to any one of claims 1 to 19 for purifying a gaseous exhaust stream comprising hydrocarbons, carbon monoxide and nitrogen oxides.

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