Improved catalysts for gasoline engine exhaust gas treatment.

Abstract

A three-way catalyst article and its use in an exhaust system for an internal combustion engine is disclosed. The catalyst article for treating exhaust gases includes a substrate including an inlet end and an outlet end having an axial length L, and a first catalyst region including a first platinum group metal (PGM) component and a first Nd component, wherein the first PGM component includes platinum, and the weight ratio of Nd to Pt in the first catalyst region is at least 2:1.

Description

[Technical Field]

[0001] The present invention relates to catalytic articles useful for treating exhaust gas emissions from gasoline engines. [Background technology]

[0002] In an internal combustion engine, hydrocarbons (HC), carbon monoxide (CO), and nitrogen oxides (NO x The exhaust gas produced by the engine contains various pollutants, including CO, CO₂, CO₂, and CO₂. Emissions control systems that include exhaust gas catalytic conversion catalysts are widely used to reduce the amount of these pollutants emitted into the atmosphere. The catalyst typically used to treat the exhaust gas of a gasoline engine is the TWC (three way catalyst). The TWC performs three main functions: (1) oxidation of CO, (2) oxidation of unburned HC, and (3) oxidation of NO₂. x is reduced.

[0003] Despite advances in TWC technology, there remains a need for improved catalytic converters for specific engine platforms that simultaneously improve performance during the cold start phase, provide better light-off performance, and provide better OSC performance during the hot transient phase across a wide range of Pd and / or Pt applications. Palladium (Pd) and rhodium (Rh) are widely used in TWC formulations to reduce harmful emissions in gasoline vehicles. However, in recent years, increasing market demand has driven up the prices of these precious metals, making them more expensive. Meanwhile, increasingly stringent environmental regulations worldwide are forcing the automotive industry to incorporate more and more precious metals into catalytic converters. Meanwhile, platinum (Pt) has become an increasingly attractive candidate for gasoline applications due to its relatively low price. Therefore, the replacement of Pd with Pt in gasoline products has attracted widespread market interest due to the much lower price of Pt compared to Pd. Simply replacing Pd with Pt in currently existing Pd-Rh TWC formulations has always resulted in poor performance due to the lower thermal stability and different chemical reactivity of Pt. Many efforts have been made to improve the performance of Pt-containing TWCs to achieve comparable or even better performance than Pd / Rh TWCs after replacing Pd with Pt. The present invention addresses these problems, among others. Summary of the Invention

[0004] One aspect of the present disclosure is directed to a catalyst article for treating exhaust gases, the catalyst article comprising: a substrate including an inlet end and an outlet end having an axial length L; and a first catalyst region including a first platinum group metal (PGM) component and a first Nd component, wherein the first PGM component comprises platinum, and a weight ratio of Nd to Pt in the first catalyst region is at least 2:1.

[0005] The present invention also includes an exhaust system for an internal combustion engine comprising the three-way catalyst component of the present invention.

[0006] The present invention also encompasses treating exhaust gases from internal combustion engines, particularly gasoline engines, which method comprises contacting the exhaust gases with a three-way catalyst component of the present invention. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 shows an embodiment according to the present invention containing a first catalyst region (single layer) having a length of 100% of the axial length L of the substrate. [Figure 2a] FIG. 1 shows an embodiment according to the invention in which a first catalyst region extends as a bottom layer over 100% of the axial length L, and a second catalyst region extends as a top layer over 100% of the axial length L. [Figure 2b] FIG. 2b shows a variation of FIG. 2a. [Figure 3a] 1 illustrates an embodiment according to the present invention in which a first catalyst region extends from the inlet end for less than 100% of the axial length L, and a second catalyst region extends from the outlet end for less than 100% of the axial length L. The combined length of the second catalyst region and the first catalyst region is less than or equal to the axial length L. [Figure 3b] FIG. 3b shows a variation of FIG. 3a. [Figure 3c] 1 illustrates an embodiment according to the present invention in which a first catalyst region extends from the inlet end less than 100% of the axial length L, and a second catalyst region extends from the outlet end less than 100% of the axial length L. The combined length of the second catalyst region and the first catalyst region is greater than the axial length L. [Figure 3d] FIG. 3C shows a variation of FIG. [Figure 4a] 1 illustrates an embodiment according to the present invention in which a first catalyst region extends less than 100% of the axial length L from the inlet end and a second catalyst region extends less than 100% of the axial length L from the outlet end. The combined length of the second catalyst region and the first catalyst region is less than or equal to the axial length L. A third catalyst region extends 100% of the axial length L and is layered as an upper layer on the first and second catalyst regions. [Figure 4b] FIG. 4b shows a variation of FIG. 4a. [Figure 4c] 1 shows an embodiment according to the present invention in which the third catalyst region is a bottom layer and extends 100% of the axial length L. 1 shows an embodiment according to the present invention in which the first catalyst region extends less than 100% of the axial length L from the inlet end and the second catalyst region extends less than 100% of the axial length L from the outlet end. The combined length of the second catalyst region and the first catalyst region is less than or equal to the axial length L. [Figure 4d] FIG. 4B shows a variation of FIG. 4C. [Figure 5a] 1 illustrates an embodiment according to the present invention, in which a first catalyst region extends less than 100% of the axial length L from the inlet end, and a second catalyst region extends less than 100% of the axial length L from the outlet end. The combined length of the second catalyst region and the first catalyst region can be less than, equal to, or greater than the axial length L. The third catalyst region extends less than 100% of the axial length L from the inlet end, and the fourth catalyst region extends less than 100% of the axial length L from the outlet end. The combined length of the third catalyst region and the fourth catalyst region can be less than, equal to, or greater than the axial length L. The first and second catalyst regions constitute a bottom layer, and the third and fourth catalyst regions constitute a top layer. [Figure 5b] FIG. 5b shows a variation of FIG. 5a. [Figure 5c] FIG. 5b shows a variation of FIG. 5a. [Figure 5d] FIG. 5b shows a variation of FIG. 5a. [Figure 6a] 1 shows an embodiment according to the present invention in which a first catalyst region extends 100% of the axial length L as a bottom layer, a second catalyst region extends 100% of the axial length L as a middle layer, and a third catalyst region extends 100% of the axial length L as a top layer. [Figure 6b] FIG. 6b shows a variation of FIG. 6a. [Figure 6c] FIG. 6b shows a variation of FIG. 6a. [Figure 7a] 1 illustrates an embodiment according to the present invention in which a first catalyst region extends less than 100% of the axial length L from the inlet end and a second catalyst region extends less than 100% of the axial length L from the outlet end. The combined length of the second catalyst region and the first catalyst region is greater than the axial length L. A third catalyst region extends 100% of the axial length L and is layered as an upper layer on the first and second catalyst regions. [Figure 7b] FIG. 7b shows a variation of FIG. 7a. [Figure 7c] FIG. 7b shows a variation of FIG. 7a. [Figure 7d] FIG. 7b shows a variation of FIG. 7a. [Figure 7e] FIG. 7b shows a variation of FIG. 7a. [Figure 7f] FIG. 7b shows a variation of FIG. 7a. [Figure 7g] 1 illustrates an embodiment according to the present invention in which a first catalyst region extends less than 100% of the axial length L from the inlet end and a second catalyst region extends less than 100% of the axial length L from the outlet end. The combined length of the second catalyst region and the first catalyst region can be less than, equal to, or greater than the axial length L. A third catalyst region extends less than 100% of the axial length L from the inlet end and is at least partially stacked on the first catalyst region and / or the second catalyst region. [Figure 7h] FIG. 7B shows a variation of FIG. 7G. [Figure 7i] FIG. 7B shows a variation of FIG. 7G. [Figure 7j] 1 illustrates an embodiment according to the present invention in which a first catalyst region extends less than 100% of the axial length L from the inlet end and a second catalyst region extends less than 100% of the axial length L from the outlet end. The combined length of the second catalyst region and the first catalyst region can be less than, equal to, or greater than the axial length L. A third catalyst region extends less than 100% of the axial length L from the outlet end and is at least partially stacked on the second catalyst region and / or the first catalyst region. [Figure 7k]FIG. 7J is a diagram showing a modification of FIG. [Figure 7l] FIG. 7J is a diagram showing a modification of FIG. DETAILED DESCRIPTION OF THE INVENTION

[0008] The present invention is directed to the catalytic treatment of combustion exhaust gases, such as those produced by gasoline and other engines, and related catalyst compositions, articles, and systems. More specifically, the present invention relates to the reduction of NOx in vehicle exhaust systems by using Pt-containing TWCs under novel designs as described in this invention. x The present inventors have discovered an effective approach to improve the performance of Pt-containing TWCs even after severe aging conditions, which will enable more applications of lower-cost Pt-containing TWCs in practical fields to replace the high-cost typical Pd / Rh TWCs. The present inventors have also discovered that the TWC performance of Pt / Rh TWCs or Pt / Pd / Rh TWCs under vehicle emission tests is improved by the present invention.

[0009] One aspect of the present disclosure is directed to a catalyst article for treating exhaust gases, the catalyst article comprising: a substrate including an inlet end and an outlet end having an axial length L; and a first catalyst region comprising a first platinum group metal (PGM) component and a first Nd component, wherein the first PGM component comprises platinum, and wherein a weight ratio of Nd to Pt in the first catalyst region is at least 2:1.

[0010] Through intensive research, the inventors have found that by incorporating a Nd component into the Pt-containing TWC catalyst composition and by finding the appropriate weight ratio of Nd to Pt in the first catalyst region, these novel designs in the Pt-containing TWC demonstrated improved catalytic properties (e.g., by using this novel Pt-containing catalyst design as described in this invention, all emissions, THC / NMHC, CO and NO were reduced during vehicle testing). x (This significantly reduced emissions.)

[0011] First catalytic region The weight ratio of Nd to Pt is based on elemental metals. In some embodiments, the weight ratio of Nd to Pt in the first catalytic region can be at least 2:1, 5:2, 3:1, or even 4:1. Alternatively, the weight ratio of Nd to Pt in the first catalytic region can be 20:1 to 2:1, 15:1 to 2:1, 10:1 to 2:1, 8:1 to 2:1, 6:1 to 2:1, 5:1 to 2:1, or 4:1 to 2:1. In other embodiments, the weight ratio of Nd to Pt in the first catalytic region can be 20:1 to 5:2, 15:1 to 5:2, 10:1 to 5:2, 8:1 to 5:2, 6:1 to 5:2, 5:1 to 5:2, or 4:1 to 5:2.

[0012] In some embodiments, the first PGM component may further comprise palladium, rhodium, or a mixture thereof, hi other embodiments, the first catalytic region is essentially free of other PGM components other than platinum.

[0013] The first catalytic region may further include a first oxygen storage capacity (OSC) material and / or a first inorganic oxide.

[0014] The first OSC material can be cerium oxide, zirconium oxide, ceria-zirconia mixed oxide, alumina-ceria-zirconia mixed oxide, or a combination thereof. More preferably, the first OSC material comprises ceria-zirconia mixed oxide, alumina-ceria-zirconia mixed oxide, or a combination thereof. The ceria-zirconia mixed oxide may further comprise a dopant, such as lanthanum, neodymium, praseodymium, or yttrium oxide. The first OSC material may also function as a support material for the first PGM component (e.g., as the first PGM support material). In some embodiments, the first OSC material comprises ceria-zirconia mixed oxide and alumina-ceria-zirconia mixed oxide.

[0015] The first inorganic oxide is preferably an oxide of an element of Groups 2, 3, 4, 5, 13, and 14. The first inorganic oxide is preferably selected from the group consisting of alumina, magnesia, silica, zirconia, barium oxide, and mixed oxides or composite oxides thereof. Particularly preferred is alumina, lanthanum-alumina, zirconia, or magnesia / alumina composite oxide. One particularly preferred first inorganic oxide is alumina or lanthanum-alumina.

[0016] The first OSC material and the first inorganic oxide can have a weight ratio of 10:1 or less, preferably 8:1 or 5:1 or less, more preferably 4:1 or 3:1 or less, and most preferably 2:1 or less.

[0017] Alternatively, the first OSC material and the first inorganic oxide can have a weight ratio of 10:1 to 1:10, preferably 8:1 to 1:8 or 5:1 to 1:5, more preferably 4:1 to 1:4 or 3:1 to 1:3, and most preferably 2:1 to 1:2.

[0018] In some embodiments, the first OSC material and the first inorganic oxide can have a weight ratio of 2:1 or less. In further embodiments, the first OSC material and the first inorganic oxide can have a weight ratio of 10:1 or less. In other further embodiments, the first OSC material and the first inorganic oxide can have a weight ratio of 20:1 or more, or 30:1 or more. In yet other further embodiments, the first OSC material and the first inorganic oxide can have a weight ratio of 40:1 or more, or 50:1 or more.

[0019] The first catalytic region may further comprise a first alkali metal or alkaline earth metal.

[0020] The first alkali metal or alkaline earth metal is preferably barium or strontium, and mixed oxides or composite oxides thereof. Preferably, the barium or strontium, if present, is supported in an amount of 0.1 to 15 wt %, more preferably 3 to 10 wt %, barium or strontium, based on the total weight of the first catalyst region.

[0021] Preferably, the barium or strontium is present as BaCO or SrCO. Such materials can be prepared by any method known in the art, such as incipient wetness impregnation or spray drying.

[0022] Neodymium (Nd) can be incorporated into the first catalyst region in a variety of ways. In other embodiments, Nd can be incorporated into the first OSC material as a dopant. In other embodiments, Nd can be incorporated into the first inorganic oxide as a dopant. In still other embodiments, Nd can be incorporated into the first catalyst region as a simple physical mixture (e.g., a physical blend). For example, Nd can be incorporated as NdO or Nd nitrate that is physically blended with the first OSC material and / or the first inorganic oxide. In other embodiments, Nd can be incorporated into the first OSC material framework (e.g., Nd is doped into the crystal lattice of the OSC solid solution material being formed). In certain embodiments, Nd can be incorporated into the first catalyst region in any combination of the above-described embodiments; for example, in some embodiments, at least a portion of the first Nd component can be supported on the first inorganic oxide.

[0023] In some embodiments, the first catalyst region can comprise at least 2 wt%, at least 3 wt%, or at least 3.5 wt% of the first Nd component (based on NdO). Alternatively, the first catalyst region can comprise 2-15 wt%, 2-10 wt%, 2-8 wt%, or 2-6 wt% of the first Nd component, 3-10 wt%, 3-8 wt%, or 3-6 wt% of the first Nd component, or 3.5-10 wt%, 3.5-8 wt%, or 3.5-6 wt% of the first Nd component (based on NdO), based on the total weight of the first catalyst region.

[0024] In certain embodiments, the first catalytic region can further comprise a transition metal component, where the transition metal is Fe, Ni, Cu, or a combination thereof. Preferably, the transition metal can be Fe and / or Ni.

[0025] In some embodiments, the first catalyst region has a surface area of ​​1 to 100 g / ft 3 , 5~90g / ft 3 , 10~80g / ft 3 , 15~70g / ft 3 , 20~60g / ft 3 , or 20 to 50 g / ft 3 The Pt loading can be as follows:

[0026] As demonstrated in the examples below, the catalyst article in this embodiment can be applied as a TWC catalyst for treating exhaust gases produced by gasoline engines.

[0027] The first catalyst region can extend over 100 percent of the axial length L (see, e.g., FIGS. 1, 2a, 2b, and 6a-6c). In some embodiments, the first catalyst region can extend over 20-99%, 30-90%, or 40-80% of the axial length L. Alternatively, the first catalyst region can extend over 30-70 percent of the axial length L. Preferably, the first catalyst region can extend over 40-60 percent, and more preferably, 45-55 percent of the axial length L (see, e.g., FIGS. 3a-5d and 7a-7l).

[0028] The total washcoat loading of the first catalyst region was 3.5 g / in 3 Less than 3.0 g / in 3 or 2.5 g / in 3 Alternatively, the total washcoat loading of the first catalyst region may be between 0.5 and 3.5 g / in 3 Preferably, it is 0.6 to 3 g / in 3 or 0.7 to 2.5 g / in 3 It could be.

[0029] Second catalytic region The catalytic article may further include a second catalytic region.

[0030] The second catalyst region may further comprise a second PGM component, a second oxygen storage capacity (OSC) material, a second alkali metal or alkaline earth metal component, and / or a second inorganic oxide.

[0031] The second PGM component may be selected from the group consisting of platinum, palladium, rhodium, and mixtures thereof, hi some embodiments, the second PGM component may be Pd, Rh, or mixtures thereof.

[0032] The second OSC material can be cerium oxide, zirconium oxide, ceria-zirconia mixed oxide, alumina-ceria-zirconia mixed oxide, or a combination thereof. More preferably, the second OSC material includes ceria-zirconia mixed oxide, alumina-ceria-zirconia mixed oxide, or a combination thereof. In addition, the second OSC material can further include one or more dopants such as lanthanum, neodymium, praseodymium, yttrium, etc. Furthermore, the second OSC material can function as a support material for the second PGM component. In some embodiments, the second OSC material includes ceria-zirconia mixed oxide and alumina-ceria-zirconia mixed oxide.

[0033] The ceria-zirconia mixed oxide may have a weight ratio of ceria to zirconia of at least 50:50, preferably greater than 60:40, more preferably greater than 70:30, or alternatively, may have a weight ratio of ceria to zirconia of less than 50:50, preferably less than 40:60, more preferably less than 30:70.

[0034] The second OSC material (e.g., ceria-zirconia mixed oxide) can be 10-90 wt %, preferably 25-75 wt %, more preferably 30-60 wt %, based on the total washcoat loading of the second catalyst region.

[0035] The loading of the second OSC material in the second catalyst region is 2 g / in 3 In some embodiments, the loading of the second OSC material in the second catalyst region can be less than 1.5 g / in 3 Below, 1.2g / in 3 Below, 1g / in 3 Below, 0.8g / in 3 or less than 0.7g / in 3 The following is the result.

[0036] The second alkali metal or alkaline earth metal is preferably barium, strontium, or a mixed oxide or composite oxide thereof. Preferably, the barium or strontium, if present, is in an amount of 0.1 to 15 wt. % barium or strontium, more preferably 3 to 10 wt. % barium or strontium, based on the total weight of the second catalyst region.

[0037] Even more preferably, the second alkali metal or alkaline earth metal is strontium, which, when present, is preferably present in an amount of 0.1 to 15 wt %, more preferably 3 to 10 wt %, based on the total weight of the second catalyst region.

[0038] The second alkali metal or alkaline earth metal is preferably a mixed oxide or composite oxide of barium and strontium. Preferably, the mixed oxide or composite oxide of barium and strontium is present in an amount of 0.1 to 15 wt %, more preferably 3 to 10 wt %, based on the total weight of the second catalyst region. More preferably, the second alkali metal or alkaline earth metal is a composite oxide of barium and strontium.

[0039] Preferably, the barium or strontium is present as BaCO or SrCO. Such materials can be prepared by any method known in the art, such as incipient wetness impregnation or spray drying.

[0040] The second inorganic oxide is preferably an oxide of an element of Groups 2, 3, 4, 5, 13, and 14. The second inorganic oxide is preferably selected from the group consisting of alumina, magnesia, silica, zirconia, barium oxide, and mixed oxides or composite oxides thereof. Particularly preferred is alumina, lanthanum-alumina, zirconia, or a magnesia / alumina composite oxide. One particularly preferred second inorganic oxide is alumina or lanthanum-alumina.

[0041] The second OSC material and the second inorganic oxide can have a weight ratio of 10:1 or less, preferably 8:1 or 5:1 or less, more preferably 4:1 or 3:1 or less, and most preferably 2:1 or less.

[0042] Alternatively, the second OSC material and the second inorganic oxide can have a weight ratio of 10:1 to 1:10, preferably 8:1 to 1:8 or 5:1 to 1:5, more preferably 4:1 to 1:4 or 3:1 to 1:3, and most preferably 2:1 to 1:2.

[0043] In some embodiments, the second OSC material and the second inorganic oxide can have a weight ratio of 2:1 or greater. In further embodiments, the second OSC material and the second inorganic oxide can have a weight ratio of 10:1 or greater. In other further embodiments, the second OSC material and the second inorganic oxide can have a weight ratio of 20:1 or greater, or 30:1 or greater. In yet other further embodiments, the second OSC material and the second inorganic oxide can have a weight ratio of 40:1 or greater, or 50:1 or greater.

[0044] The total washcoat loading of the second catalyst region was 3.5 g / in 3 Less than 3.0 g / in 3 or 2.5 g / in 3 Alternatively, the total washcoat loading of the first catalyst region may be between 0.5 and 3.5 g / in 3 Preferably, it is 0.6 to 3 g / in 3 or 0.7 to 2.5 g / in 3 It could be.

[0045] The second catalyst region can extend over 100 percent of the axial length L (see, eg, Figures 2a, 2b, and 6a-6c).

[0046] The second catalyst region can extend over 30 to 70 percent of the axial length L. Preferably, it can extend over 40 to 60 percent, more preferably 45 to 55 percent, of the axial length L, and most preferably, the combined length of the second region and the first region is equal to or greater than the axial length L (see, e.g., Figures 3a-5d and 7a-7l).

[0047] The second catalyst region can overlap the first catalyst region over 0.1 to 99 percent of the axial length L (see, e.g., Figures 3c and 3d; the first catalyst region can be stacked on the second catalyst region, or the second catalyst region can be stacked on the first catalyst region). Alternatively, the combined length of the second catalyst region and the first catalyst region can be equal to the axial length L (see, e.g., Figures 3a and 3b). In yet another alternative, the combined length of the second catalyst region and the first catalyst region can be less than the axial length L, e.g., 95%, 90%, 80%, or 70% or less of the axial length L.

[0048] In some embodiments, the first catalytic region may be supported / deposited directly on the substrate. In certain embodiments, the second catalytic region may be supported / deposited directly on the substrate.

[0049] The third catalytic region The catalytic article may further include a third catalytic region.

[0050] The third catalyst region may further comprise a third PGM component, a third oxygen storage capacity (OSC) material, a third alkali metal component or alkaline earth metal component, and / or a third inorganic oxide.

[0051] The third PGM component may be selected from the group consisting of platinum, palladium, rhodium, and mixtures thereof, hi some embodiments, the third PGM component may be Pd, Rh, or mixtures thereof.

[0052] The third OSC material may be cerium oxide, zirconium oxide, ceria-zirconia mixed oxide, alumina-ceria-zirconia mixed oxide, or a combination thereof. More preferably, the third OSC material includes ceria-zirconia mixed oxide, alumina-ceria-zirconia mixed oxide, or a combination thereof. In addition, the third OSC material may further include one or more dopants such as lanthanum, neodymium, praseodymium, yttrium, etc. Furthermore, the third OSC material may function as a support material for the third PGM component. In some embodiments, the third OSC material includes ceria-zirconia mixed oxide and alumina-ceria-zirconia mixed oxide.

[0053] The ceria-zirconia mixed oxide may have a weight ratio of ceria to zirconia of at least 50:50, preferably greater than 60:40, more preferably greater than 75:25, or alternatively, may have a weight ratio of ceria to zirconia of less than 50:50, preferably less than 40:60, more preferably less than 25:75.

[0054] The third OSC material (e.g., ceria-zirconia mixed oxide) can be 10-90 wt %, preferably 25-75 wt %, more preferably 30-60 wt %, based on the total washcoat loading of the third catalyst region.

[0055] The loading of the third OSC material in the third catalyst region is 1.5 g / in 3 In some embodiments, the loading of the third OSC material in the second catalyst region can be less than 1.2 g / in 3 Below, 1.0g / in 3 Below, 0.9g / in 3 Below, 0.8g / in 3 or less than 0.7g / in 3 The following is the result.

[0056] The total washcoat loading of the third catalyst region was 3.5 g / in 3 Less than 3.0 g / in3 Below 2.5g / in 3 or less than 2g / in 3 It can be the following:

[0057] The third alkali metal or alkaline earth metal is preferably barium, strontium, or a mixed oxide or composite oxide thereof. Preferably, the barium or strontium, if present, is in an amount of 0.1 to 15 wt. % barium or strontium, more preferably 3 to 10 wt. % barium or strontium, based on the total weight of the third catalytic region.

[0058] Even more preferably, the third alkali metal or alkaline earth metal is strontium, which, when present, is preferably present in an amount of 0.1 to 15 wt %, more preferably 3 to 10 wt %, based on the total weight of the third catalyst region.

[0059] The third alkali metal or alkaline earth metal is preferably a mixed oxide or composite oxide of barium and strontium. Preferably, the mixed oxide or composite oxide of barium and strontium is present in an amount of 0.1 to 15 wt %, more preferably 3 to 10 wt %, based on the total weight of the third catalyst region. More preferably, the third alkali metal or alkaline earth metal is a composite oxide of barium and strontium.

[0060] Preferably, the barium or strontium is present as BaCO or SrCO. Such materials can be prepared by any method known in the art, such as incipient wetness impregnation or spray drying.

[0061] The third inorganic oxide is preferably an oxide of an element of Groups 2, 3, 4, 5, 13, and 14. The third inorganic oxide is preferably selected from the group consisting of alumina, magnesia, silica, zirconia, barium oxide, and mixed oxides or composite oxides thereof. Particularly preferred is alumina, lanthanum-alumina, zirconia, or magnesia / alumina composite oxide. One particularly preferred third inorganic oxide is alumina or lanthanum-alumina.

[0062] The third OSC material and the third inorganic oxide can have a weight ratio of 10:1 or less, preferably 8:1 or 5:1 or less, more preferably 4:1 or 3:1 or less, and most preferably 2:1 or less.

[0063] Alternatively, the third OSC material and the third inorganic oxide can have a weight ratio of 10:1 to 1:10, preferably 8:1 to 1:8 or 5:1 to 1:5, more preferably 4:1 to 1:4 or 3:1 to 1:3, and most preferably 2:1 to 1:2.

[0064] In some embodiments, the third OSC material and the third inorganic oxide can have a weight ratio of 2:1 or greater. In further embodiments, the third OSC material and the third inorganic oxide can have a weight ratio of 10:1 or greater. In other further embodiments, the third OSC material and the third inorganic oxide can have a weight ratio of 20:1 or greater, or 30:1 or greater. In yet other further embodiments, the third OSC material and the third inorganic oxide can have a weight ratio of 40:1 or greater, or 50:1 or greater.

[0065] The third catalyst region can extend over 100 percent of the axial length L (see, eg, Figures 4a-4d and 6a-6c).

[0066] The third catalyst region can be less than the axial length L, for example, 95%, 90%, 80%, or 70% or less of the axial length L (see, for example, Figures 5a-5d and 7g-7l).

[0067] The second catalyst region can overlap the first catalyst region over 0.1 to 99 percent of the axial length L (see, e.g., Figures 7a-7l), the first catalyst region can be stacked on the second catalyst region, or the second catalyst region can be stacked on the first catalyst region). Alternatively, either the second region or the first region can extend over 30 to 70 percent of the axial length L. Preferably, it can extend over 40 to 60 percent, more preferably 45 to 55 percent, of the axial length L, and most preferably, the combined length of the second region and the first region is equal to or less than the axial length L (see, e.g., Figures 4a-4d).

[0068] The fourth catalytic region The catalytic article may further include a fourth catalytic region.

[0069] The fourth catalyst region may further comprise a fourth PGM component, a fourth oxygen storage capacity (OSC) material, a fourth alkali or alkaline earth metal component, and / or a fourth inorganic oxide.

[0070] The fourth PGM component may be selected from the group consisting of platinum, palladium, rhodium, and mixtures thereof, hi some embodiments, the fourth PGM component may be Pd, Rh, or mixtures thereof.

[0071] The fourth catalytic region may have the same or similar composition as the third catalytic region.

[0072] The fourth catalytic region may be less than the axial length L, for example, 95%, 90%, 80%, or 70% or less of the axial length L.

[0073] Alternatively, either the fourth catalyst region or the third catalyst region can extend over 30 to 70 percent of the axial length L. Preferably, it can extend over 40 to 60 percent, more preferably 45 to 55 percent, of the axial length L, and most preferably, the combined length of the fourth catalyst region and the third catalyst region is equal to or greater than the axial length L (see, e.g., Figures 5a-5d).

[0074] The catalyst article of the present invention may contain additional components known to those skilled in the art. For example, the composition of the present invention may further comprise at least one binder and / or at least one surfactant. When a binder is present, a dispersible alumina binder is preferred.

[0075] Base material Preferably, the substrate is a flow-through monolith. Alternatively, the substrate may be a wall-flow filter.

[0076] The flow-through monolith substrate has a first surface and a second surface defining a longitudinal direction therebetween. The flow-through monolith substrate has a plurality of channels extending between the first surface and the second surface. The plurality of channels extend longitudinally and provide a plurality of interior surfaces (e.g., wall surfaces defining each channel). Each of the plurality of channels has an opening in the first surface and an opening in the second surface. For the avoidance of doubt, the flow-through monolith substrate is not a wall-flow filter.

[0077] The first surface is typically at the inlet end of the substrate and the second surface is at the outlet end of the substrate.

[0078] The channels may be of constant width, and each of the plurality of channels may have a uniform channel width.

[0079] Preferably, in a plane perpendicular to the longitudinal direction, the monolith substrate has 300 to 900 channels per square inch, preferably 400 to 800 channels per square inch. For example, on the first face, the density of the open first channels and closed second channels is 600 to 700 channels per square inch. These channels can have cross sections that are rectangular, square, circular, oval, triangular, hexagonal, or other polygonal shapes.

[0080] The monolith substrate acts as a support to hold the catalytic material. Suitable materials for forming the monolith substrate include ceramic-like materials such as cordierite, silicon carbide, silicon nitride, zirconia, mullite, spodumene, alumina-silica magnesia, or zirconium silicate, or porous refractory metals. Such materials and their use in the manufacture of porous monolith substrates are well known in the art.

[0081] It should be noted that the flow-through monolith substrates described herein are single components (i.e., a single brick). Nevertheless, when forming waste treatment systems, the substrates used may be formed by bonding multiple channels together, or by bonding multiple smaller substrates together as described herein. Such techniques, along with suitable casings and configurations of waste treatment systems, are well known in the art.

[0082] In embodiments in which the catalyst article of the present invention comprises a ceramic substrate, the ceramic substrate can be made of any suitable refractory material, such as alumina, silica, ceria, zirconia, magnesia, zeolites, silicon nitride, silicon carbide, zirconium silicate, magnesium silicate, aluminosilicates and metalloaluminosilicates (such as cordierite and spodumene), or mixtures or mixed oxides of any two or more thereof. Cordierite, magnesium aluminosilicate, and silicon carbide are particularly preferred.

[0083] In embodiments in which the catalytic article of the present invention comprises a metal substrate, the metal substrate may be made of any suitable metal, particularly heat-resistant metals and metal alloys such as titanium and stainless steel, and ferritic alloys containing iron, nickel, chromium, and / or aluminum in addition to other trace metals.

[0084] Another aspect of the present disclosure is a method for producing NOx using the catalytic articles described herein. x The present invention is directed to a method for treating vehicle exhaust gases containing Pt, CO, and HC. Catalytic converters with Pt-containing TWCs made according to this method exhibit improved catalytic properties compared to conventional TWCs (having the same PGM loading), and also reduce NO from gasoline-powered vehicles tested. x It also exhibits significantly lower emissions than bench-aged TWC for CO, CO, and HC (see, e.g., Examples 1-5 and Tables 1-6).

[0085] Another aspect of the present disclosure is directed to a system for treating vehicle exhaust gases that includes a catalytic article as described herein along with a conduit for transporting the exhaust gases through the system.

[0086] definition The term "region," as used herein, refers to an area on a substrate that is typically obtained by drying and / or baking a washcoat. A "region" can be disposed or carried on the substrate as, for example, a "layer" or a "zone." The area or arrangement on the substrate is generally controlled during the process of applying the washcoat to the substrate. A "region" typically has a distinct boundary or edge (i.e., it is possible to distinguish one region from another using conventional analytical techniques).

[0087] Typically, a "region" has a substantially uniform length. Reference to a "substantially uniform length" in this context refers to a length that does not deviate from its average value (e.g., the difference between the maximum and minimum length) by more than 10%, preferably a length that does not deviate from its average value by more than 5%, and more preferably a length that does not deviate from its average value by more than 1%.

[0088] Preferably, each "region" has a substantially uniform composition (i.e., there is no substantial difference in the composition of the washcoat when comparing one portion of the region to another portion of the region). Substantially uniform composition in this context refers to a material (e.g., region) that has a composition difference of 5% or less, usually 2.5% or less, and most commonly 1% or less when comparing one portion of the region to another portion of the region.

[0089] The term "zone," as used herein, refers to a region having a length less than the entire length of the substrate, such as a length of 75% or less of the entire length of the substrate. A "zone" typically has a length of at least 5% (e.g., 5% or more) of the entire length of the substrate (i.e., a substantially uniform length).

[0090] The overall length of a substrate is the distance between its inlet end and its outlet end (eg, both ends of the substrate).

[0091] As used herein, any reference to a "zone disposed at the inlet end of the substrate" refers to a zone disposed on or carried by a substrate that is closer to the inlet end of the substrate than to the outlet end of the substrate. Thus, the midpoint of the zone (i.e., a point at half its length) is closer to the inlet end of the substrate than to the outlet end of the substrate. Similarly, as used herein, any reference to a "zone disposed at the outlet end of the substrate" refers to a zone disposed on or carried by a substrate that is closer to the outlet end of the substrate than to the inlet end of the substrate. Thus, the midpoint of the zone (i.e., a point at half its length) is closer to the outlet end of the substrate than to the inlet end of the substrate.

[0092] When the substrate is a wall-flow filter, generally any reference to "a zone disposed at the inlet end of the substrate" refers to a zone disposed on or carried by the substrate, (a) a zone that is closer to the inlet end (e.g., open end) of an inlet channel of a substrate than to the closed end (e.g., blocked or plugged end) of the inlet channel; and / or (b) Refers to a zone that is closer to the closed end (e.g., blocked or plugged end) of an outlet channel of a substrate than to the outlet end (e.g., open end) of the outlet channel.

[0093] Thus, the midpoint of the zone (i.e., the point at half its length) is (a) closer to the inlet end of the inlet channel of the substrate than to the closed end of the inlet channel, and / or (b) closer to the closed end of the outlet channel of the substrate than to the outlet end of the outlet channel.

[0094] Similarly, when the substrate is a wall-flow filter, any reference to "a zone disposed at the outlet end of the substrate" includes a zone disposed on or carried by the substrate, (a) a zone that is closer to the outlet end (e.g., open end) of the outlet channel of the substrate than to the closed end (e.g., blocked or plugged end) of the outlet channel; and / or (b) Refers to a zone that is closer to the closed end (e.g., blocked or plugged end) of an inlet channel of a substrate than to the inlet end (e.g., open end) of the inlet channel.

[0095] Thus, the midpoint of the zone (i.e., the point at half its length) is (a) closer to the outlet end of the outlet channel of the substrate than to the closed end of the outlet channel, and / or (b) closer to the closed end of the inlet channel of the substrate than to the inlet end of the inlet channel.

[0096] When the washcoat is present on the wall of a wall-flow filter (ie, the zone is within the wall), the zone may satisfy both (a) and (b).

[0097] The term "washcoat" is well known in the art and typically refers to an adherent coating applied to a substrate during the production of a catalyst.

[0098] The acronym "PGM" as used herein refers to "platinum group metals." The term "platinum group metals" generally refers to metals selected from the group consisting of Ru, Rh, Pd, Os, Ir, and Pt, preferably metals selected from the group consisting of Ru, Rh, Pd, Ir, and Pt. Generally, the term "PGM" preferably refers to metals selected from the group consisting of Rh, Pt, and Pd.

[0099] The term "mixed oxide," as used herein, generally refers to a mixture of oxides in a single phase, as conventionally known in the art. The term "complex oxide," as used herein, generally refers to a composition of oxides having two or more phases, as conventionally known in the art.

[0100] The phrase "consisting essentially of," as used herein, limits the scope of a feature to include the specified materials or steps and any other materials or steps, e.g., trace impurities, that do not substantially affect the basic properties of the feature. The phrase "consisting essentially of" encompasses the phrase "consisting of."

[0101] The term "substantially free," as used herein with respect to a material, typically means a small amount of material relative to the contents of a region, layer, or zone, such as 5% by weight or less, preferably 2% by weight or less, and more preferably 1% by weight or less. The term "substantially free" encompasses the term "free."

[0102] The term "essentially free," when used herein with respect to a material, typically means that the material is present in trace amounts relative to the contents of a region, layer, or zone, such as 1% by weight or less, preferably 0.5% by weight or less, and more preferably 0.1% by weight or less. The term "essentially free" encompasses the term "free."

[0103] As used herein, any reference to an amount, particularly a total amount, of dopant expressed as a weight percent refers to the weight of the support material or refractory metal oxide thereof.

[0104] The term "loading" as used herein refers to g / ft on a metal weight basis. 3 Refers to a measurement in units of .

[0105] The following examples are merely illustrative of the present invention, and those skilled in the art will recognize many variations that are within the spirit and scope of the claims. [Example]

[0106] Example 1: Vehicle Test Procedures and Results Comparison catalyst A: First catalytic region: The first catalytic region consisted of a first OSC mixed oxide (containing 5 wt. % NdO) and Pt supported on a washcoat of La-stabilized alumina. The washcoat loading of the first catalytic region was approximately 2.2 g / in. 3 The Pt loading is 49 g / ft 3 The weight ratio of Nd to Pt in the first catalyst region was 1.7:1, and the first catalyst region contained about 2.5 wt % Nd2O3.

[0107] Next, using standard coating procedures, a first washcoat was applied to both end faces of the ceramic substrate to a target coating depth of 100% of the substrate length (600 cpsi, 4.3 mil wall thickness) and dried at 100°C.

[0108] Second catalytic region: The second catalytic region consisted of a second CeZr mixed oxide and Rh supported on a washcoat of La-stabilized alumina. The washcoat loading for the second catalytic region was about 1.3 g / in. 3 The Rh loading is 6 g / ft 3 It was.

[0109] A second washcoat was then coated from the outlet face of the ceramic substrate containing the first catalyst region using standard coating procedures, with a coating depth targeted to 100% of the substrate length, dried at 100°C, and calcined at 500°C for 45 minutes.

[0110] Catalyst B: Catalyst B was prepared according to the same procedure as Comparative Catalyst A, except that additional neodymium nitrate was added at 80 g / ft 3 The Nd content was added to the washcoat of the first catalyst region by physical mixing. The weight ratio of Nd to Pt in the first catalyst region was 3.3:1, and the first catalyst region contained approximately 4.8 wt% NdO.

[0111] Bench-aged samples of Catalyst B and Comparative Catalyst A were tested in Vehicle A with a 1.5-liter engine using the Worldwide Light Duty Testing Procedure (WLTP). Bench aging was performed in a 6.1-liter engine with a catalyst peak bed temperature of approximately 980°C, a four-mode aging cycle, and the same 200 hours of operation. Vehicle exhaust dilution bag data results for the bench-aged parts are shown in Table 1. Inventive Catalyst B reduced THC, CO, and NO compared to Comparative Catalyst A. x exhibits excellent activity in controlling emissions of x (See the performance improvements of approximately 17%, 23%, and 20%, respectively.)

[0112] [Table 1]

[0113] Example 2: Vehicle Test Procedures and Results The comparative catalyst was the same as comparative catalyst A used in Example 1.

[0114] Catalyst C: Catalyst C was prepared according to the same procedure as Comparative Catalyst A, except that in the first catalyst zone, an additional 40 g / ft of Nd nitrate was added. 3 The Nd content of the washcoat was 1.0 wt. The weight ratio of Nd to Pt in the first catalytic region was 2.5:1, and the first catalytic region contained about 3.7 wt. % Nd2O3.

[0115] Catalyst D: Catalyst D was prepared according to the same procedure as Comparative Catalyst A, except that in the first catalyst zone, an additional 120 g / ft of Nd nitrate was added. 3 The Nd content of the washcoat was 1.0 wt. The weight ratio of Nd to Pt in the first catalyst region was 4.1:1, and the first catalyst region contained about 6 wt. % Nd2O3.

[0116] Bench-aged samples of Catalyst C, Catalyst D, and Comparative Catalyst A were tested in Vehicle B with a 1.5-liter engine using the World Wide Harmonized Exhaust Emissions and Fuel Economy Test Procedure (WLTP). Vehicle B has a different calibration than Vehicle A. Bench-aging was performed in a 6.1-liter engine with a catalyst peak bed temperature of approximately 980°C, a four-mode aging cycle, and the same 200 hours of operation. Vehicle exhaust dilution bag data results for the bench-aged parts are shown in Table 2. Catalyst C of the present invention reduced THC and NO compared to Comparative Catalyst A and Catalyst D. x It showed excellent activity for emission control, and as shown in catalyst D, the Nd content was increased to 120 g / ft 3 Further increasing the concentration of THC and NO x Although the performance against the catalyst is inferior, it is comparable to that of Comparative Catalyst A.

[0117] [Table 2]

[0118] Example 3: Vehicle Test Procedures and Results Comparison catalyst E: First catalytic region: The first catalytic region consisted of Pt and Pd supported on a first OSC (Nd-free), La-stabilized alumina, and a Ba-promoter washcoat. The washcoat loading for the first catalytic region was approximately 2.3 g / in. 3 and the Pt loading is 22 g / ft 3 The Pd loading is 24 g / ft 3 The first catalytic region does not contain Nd.

[0119] This washcoat was then coated onto the ceramic substrate from the inlet face using standard coating procedures (600 cpsi, 2.5 mil wall thickness) to a target coating depth of 100% of the substrate length and dried at 100°C.

[0120] Second catalytic region: The second catalytic region consisted of Pt and Rh supported on a second CeZr mixed oxide and La-stabilized alumina washcoat. The washcoat loading for the second catalytic region was about 1.5 g / in. 3 The Pt loading is 3 g / ft 3 , Rh loading is 6g / ft 3 It was.

[0121] A second washcoat was then coated from the outlet face of the ceramic substrate containing the first catalyst region described above using standard coating procedures with a total coating depth targeted at 100% of the substrate length, dried at 100°C, and calcined at 500°C for 45 minutes.

[0122] Catalyst F: Catalyst F was prepared according to the same procedure as Comparative Catalyst E, except that additional neodymium nitrate was added at 80 g / ft 3The Nd content was added to the washcoat of the first catalyst region by physical mixing. The weight ratio of Nd to Pt in the first catalyst region was 3.6:1, and the first catalyst region contained approximately 2.3 wt% NdO.

[0123] Bench-aged samples of Catalyst F and Comparative Catalyst E were tested in Vehicle A with a 1.5-liter engine using the World Wide Harmonized Exhaust Emissions and Fuel Economy Test Procedure (WLTP). Bench-aging was performed in a 6.1-liter engine with a catalyst peak bed temperature of approximately 980°C, a four-mode aging cycle, and the same 200 hours of operation. Vehicle exhaust dilution bag data results for the bench-aged parts are shown in Table 3. Inventive Catalyst F reduced THC, CO, and NO compared to Comparative Catalyst E. x showed superior activity for controlling emissions of THC, CO, and NO relative to Comparative Catalyst E. x (See the performance improvements of approximately 10%, 16%, and 21%, respectively.)

[0124] [Table 3]

[0125] Example 4: Vehicle Test Procedures and Results Catalyst G: First catalytic region: The first catalytic region consisted of a first OSC mixed oxide (containing 5 wt. % NdO), Pt supported on a washcoat of La-stabilized alumina. The washcoat loading of the first catalytic region was approximately 2.2 g / in. 3 The Pt loading is 36 g / ft 3 The weight ratio of Nd to Pt in the first catalyst region was 2.3:1, and the first catalyst region contained about 2.5 wt % Nd2O3.

[0126] The washcoat was then coated onto both end faces of a ceramic substrate (600 cpsi, 2.5 mil wall thickness) using standard coating procedures, with a coating depth targeted to 100% of the substrate length, dried at 100°C, and fired at 500°C for 45 minutes.

[0127] Second catalytic region: The second catalytic region consisted of a second CeZr mixed oxide and Rh supported on a washcoat of La-stabilized alumina. The washcoat loading for the second catalytic region was about 1.5 g / in. 3 The Rh loading is 4 g / ft 3 It was.

[0128] A second washcoat was then coated onto both end faces of the ceramic substrate containing the first catalyst region using standard coating procedures, with the total coating depth targeted to 100% of the substrate length, dried at 100°C, and calcined at 500°C for 45 minutes.

[0129] Catalyst H: Catalyst H was prepared according to the same procedure as Catalyst G, except that a different OSC mixed oxide (containing 6.5 wt. % NdO) was used in the first catalyst zone. The weight ratio of Nd to Pt in the first catalyst zone was 3:1, and the first catalyst zone contained approximately 3.3 wt. % NdO.

[0130] Catalyst I: Catalyst I was prepared according to the same procedure as catalyst G, except that a different OSC mixed oxide (containing 10 wt. % NdO) was used in the first catalyst zone. The weight ratio of Nd to Pt in the first catalyst zone was 4.5:1, and the first catalyst zone contained approximately 5 wt. % NdO.

[0131] Bench-aged samples of catalysts G, H, and I were tested in Vehicle A with a 1.5-liter engine using the World Wide Harmonized Exhaust Emissions and Fuel Economy Test Procedure (WLTP). Bench-aging was performed in a 6.1-liter engine with a catalyst peak bed temperature of approximately 980°C, a four-mode aging cycle, and the same 150 hours of operation. Vehicle exhaust dilution bag data results for the bench-aged parts are shown in Table 4. Catalyst H reduced THC, CO, and NO. x Although catalysts G and I show superior activity for emission control, catalysts G and I perform equally well. The results show that the performance of the Pt / Rh TWC is improved by introducing an additional 1.5 wt.% Nd2O3 on the surface of the first OSC3 material. When the loading of Nd2O3 on the surface of the first OSC4 material used in catalyst I is further increased to 5 wt.%, the performance of the Pt-TWC is comparable.

[0132] [Table 4]

[0133] Example 5: Vehicle Test Procedures and Results Comparative catalyst J: First catalytic region: The first catalyst region consisted of Pt and Pd supported on a washcoat of the first OSC (Nd-free), La-stabilized alumina, Ni-promoter, and Ba-promoter. The washcoat loading of the first catalyst region was approximately 2.4 g / in. 3 The Pd loading is 43 g / ft 3 The Pt loading is 41 g / ft 3 The first catalytic region does not contain Nd.

[0134] This washcoat was then coated (600 cpsi, 2.5 mil wall thickness) from the inlet face of the ceramic substrate using standard coating procedures with a coating depth targeted at 100% of the substrate length, dried at 100°C, and fired at 500°C for 45 minutes.

[0135] Second catalytic region: The second catalytic region consisted of Pt and Rh supported on a second CeZr mixed oxide and La-stabilized alumina washcoat. The washcoat loading for the second catalytic region was about 1.5 g / in. 3 The Pt loading is 2 g / ft 3 , Rh loading is 4g / ft 3 It was.

[0136] A second washcoat was then coated from the outlet face of the ceramic substrate containing the first catalyst region described above using standard coating procedures with a total coating depth targeted at 100% of the substrate length, dried at 100°C, and calcined at 500°C for 45 minutes.

[0137] Catalyst K: Catalyst K was prepared according to the same procedure as Comparative Catalyst J, except that in the first catalytic zone, additional Nd oxide and Fe nitrate were added to a Nd content of 80 g / ft 3 and Fe content 12g / ft 3 The first catalyst zone was added by physical mixing at 100° C. The weight ratio of Nd to Pt in the first catalyst zone was 2:1, and the first catalyst zone contained about 2.2 wt % Nd2O3.

[0138] Bench-aged samples of Catalyst K and Comparative Catalyst J were tested in Vehicle C with a 1.5-liter engine using the World Wide Harmonized Exhaust Emissions and Fuel Economy Test Procedure (WLTP). Bench-aging was performed on a 6.1-liter engine with the same 260-hour operation, a four-mode aging cycle, and a catalyst peak bed temperature of approximately 980°C. During vehicle testing, either Catalyst K or Comparative Catalyst J was placed in a closed-coupled position upstream of the aftertreatment tailpipe, with the same commercially available Pt / Rh catalyst placed in an underfloor position downstream of the tailpipe. Vehicle exhaust dilution bag data results for the bench-aged parts are shown in Table 5. Catalyst K of the present invention reduced THC, CO, and NO compared to Comparative Catalyst J. x exhibits excellent activity in controlling the emission of x(See the approximately 13% and 23% improvement in performance, respectively.) Vehicle exhaust direct emissions results for Catalyst K and Comparative Catalyst J after bench aging are shown in Table 6. Inventive Catalyst K showed significant performance improvements for all emissions (e.g., THC, CO / 10, and NO) compared to Comparative Catalyst J. x (See the performance improvements of approximately 35%, 10%, and 39%, respectively.)

[0139] [Table 5]

[0140] [Table 6]

Claims

1. 1. A catalytic article for treating exhaust gases, comprising: a substrate including an inlet end and an outlet end having an axial length L; a first catalytic region comprising a first platinum group metal (PGM) component and a first Nd component; the first PGM component comprises platinum; A catalytic article for treating exhaust gases, wherein the weight ratio of Nd to Pt in said first catalytic region is at least 2:

1.

2. The catalytic article of claim 1 , wherein the first catalytic region further comprises a first oxygen storage capacity (OSC) material and / or a first inorganic oxide.

3. 3. The catalytic article of claim 2, wherein the first OSC material is selected from the group consisting of cerium oxide, ceria-zirconia mixed oxide, and alumina-ceria-zirconia mixed oxide.

4. 4. The catalytic article according to claim 2 or 3, wherein the first inorganic oxide is selected from the group consisting of alumina, magnesia, silica, zirconia, lanthanum, cerium, neodymium, praseodymium, yttrium oxide, and mixed or composite oxides thereof.

5. The catalyst article according to any one of claims 2 to 4, wherein at least a portion of the first Nd component is supported on the first inorganic oxide.

6. 6. The catalytic article of any one of claims 1 to 5, wherein the weight ratio of Nd to Pt in the first catalytic region is at least 5:

2.

7. The first catalytic region is Nd ２ O ３ 7. The catalyst article of claim 1, comprising at least 2 wt. % of said first Nd component, based on the total weight of said catalyst article.

8. The catalytic article of any one of claims 1 to 7, wherein the first catalytic region further comprises a transition metal component.

9. The catalyst article of any one of claims 1 to 8, wherein the first PGM component further comprises Pd, Rh, or a combination thereof.

10. The catalytic article of any one of claims 1 to 9, further comprising a second catalytic region.

11. The catalytic article of claim 10 , wherein the second catalytic region comprises a second PGM component.

12. 12. The catalytic article of claim 11, wherein the second PGM component is selected from the group consisting of platinum, palladium, rhodium, and mixtures thereof.

13. The catalytic article of any one of claims 10 to 12, wherein the second catalytic region further comprises a second OSC material and / or a second inorganic oxide.

14. 14. The catalytic article of claim 13, wherein the second OSC material is selected from the group consisting of cerium oxide, zirconium oxide, ceria-zirconia mixed oxide, and alumina-ceria-zirconia mixed oxide.

15. 15. The catalytic article of claim 13 or 14, wherein the second inorganic oxide is selected from the group consisting of alumina, magnesia, silica, zirconia, lanthanum, cerium, neodymium, praseodymium, yttrium oxides, and mixed or composite oxides thereof.

16. The catalyst article of any one of claims 1 to 15, wherein the first catalyst region extends over the axial length L.

17. The catalytic article of any one of claims 10 to 16, wherein the second catalytic region extends over the axial length L.

18. 18. The catalytic article of claim 16 or 17, wherein the first catalytic region is supported / deposited directly on the substrate.

19. 18. The catalytic article of claim 16 or 17, wherein the second catalytic region is supported / deposited directly on the substrate.

20. The catalyst article of any one of claims 1 to 15, wherein the first catalyst region extends over less than the axial length L.

21. The catalyst article of any one of claims 10 to 16, wherein the second catalyst region extends over less than the axial length L.

22. 22. The catalytic article of claim 20 or 21, wherein the first catalytic region is supported / deposited directly on the substrate.

23. 22. The catalytic article of claim 20 or 21, wherein the second catalytic region is supported / deposited directly on the substrate.

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