Surface modified alumina compositions for gasoline exhaust applications containing perovskite type compounds - Patents.com

Abstract

A composition is provided comprising alumina, the alumina being surface-modified with a perovskite compound of formula (I), x-y A' y B i-z B' z O h (In the formula, A is an ion of a metal selected from the group consisting of Li, Na, K, Cs, Mg, Sr, Ba, Ca, Y, La, Ce, Pr, Nd, and Gd; A' is an ion of a metal selected from the group consisting of Li, Na, K, Cs, Mg, Sr, Ba, Ca, Y, La, Ce, Pr, Nd, and Gd; B is an ion of a metal selected from the group consisting of Cu, Mn, Mo, Co, Fe, Ni, Cr, Ti, Zr, Al, Ga, Sc, Nb, V, W, Bi, Zn, Sn A' is an ion of a metal selected from the group consisting of Cu, Mn, Mo, Co, Fe, Ni, Cr, Ti, Zr, Al, Ga, Sc, Nb, V, W, Bi, Zn, Sn, Pt, Rh, Pd, Ru, Au, Ag, and Ir, and x is 0.7-1, y is 0-0.5, and z is 0-0.5. A catalyst article comprising a substrate having this composition is used in a method for treating exhaust gas from a gasoline engine operating under stoichiometric conditions. JPEG2025505489000008.jpg7128

Description

[Technical field]

[0001] The present invention relates to compositions comprising alumina surface-modified with a perovskite-type compound, methods for making such compositions, compositions obtained or obtainable by such methods, catalytic articles, emission treatment systems, and methods for treating exhaust gases. [Background technology]

[0002] Three-way catalysts (TWCs) are used to separate CO, HC, and NO from the exhaust of gasoline engines at a stoichiometric air-fuel ratio. x to harmless compounds (about 98%). Specifically, the oxidation of CO and HC to CO2 and water vapor (HO) is primarily catalyzed by Pd, while NO x The reduction of N2 to N2 is primarily catalyzed by Rh. Modern TWCs use supported platinum group metal (PGM) catalysts (Pd, Rh, Pt, etc.) deposited on single, bi- or multi-layer supports, with the support material consisting of high surface area metal oxides, primarily stabilized alumina, and ceria-containing oxygen storage materials. The supported catalysts are washcoated onto ceramic monolith substrates.

[0003] Ce 4+ / Ce 3+ Cerium oxide (CeO2) is known for its high oxygen storage capacity (OSC) due to its redox couple function. x O y ) plays an important role in TWC performance. Ce x O y In addition to providing a high surface area for PGM metal dispersion, Ce can also assist in the feedback control of stoichiometric conditions by capturing or donating oxygen during fuel lean / rich perturbation. x O y When zirconium oxide (ZrO2) is added to the fluorite structure (CZO), Ce x Oy The thermal stability of the OSC is improved and the formation of oxygen vacancies enhances the mobility of lattice oxygen. Other unique elements (Y, Nd, La, Pr, etc.) are also added to the OSC formulation to further enhance the TWC performance.

[0004] ABO 3-δ Perovskite-type materials are known in the art and can exhibit significant variations in oxygen non-stoichiometry δ upon reaction with gas-phase oxygen. Perovskites with improved composition also exhibit OSC capacity and intrinsic TWC activity. In general, the OSC and catalytic activity of perovskite oxides are highly dependent on the nature of the B-site cations, while A-site cations have been found to be important in perovskite structure formation by influencing the vacancy density and charge-valence balance. Oxygen uptake and release is associated with the presence of structural defects and changes in the oxidation state of the B-site cations. At temperatures below 600°C, surface oxygen species (α) are adsorbed on the oxide surface, while at higher temperatures, bulk oxygen from the lattice, called interfacial oxygen (β), is activated and participates in the catalytic reaction by the Mars-van-Krevelen mechanism. Furthermore, incorporation of PGM metals into the perovskite structure has been reported to result in "intelligent catalysis" (PGM transport between bulk and surface under redox conditions), which offers potential mitigation of metal sintering under harsh automotive conditions.

[0005] However, the main limitations of using perovskites for emission reduction stem from their reduced ability to develop large surface areas (i.e., they have low surface-to-volume ratios). Furthermore, they sinter dramatically above 600 °C and can also undergo phase transformations / segregation under redox conditions. Summary of the Invention

[0006] One aspect of the present disclosure is a composition comprising alumina, the alumina being surface-modified with a perovskite compound of formula (I), x-y A' y B 1-z B' zO3 (wherein A is an ion of a metal selected from the group consisting of Li, Na, K, Cs, Mg, Sr, Ba, Ca, Y, La, Ce, Pr, Nd, and Gd; A' is an ion of a metal selected from the group consisting of Li, Na, K, Cs, Mg, Sr, Ba, Ca, Y, La, Ce, Pr, Nd, and Gd; B is an ion of a metal selected from the group consisting of Cu, Mn, Mo, Co, Fe, Ni, Cr, Ti, Zr, Al, Ga, Sc, Nb, V, W, Bi, Zn, Sn, Pt , B' is an ion of a metal selected from the group consisting of Cu, Mn, Mo, Co, Fe, Ni, Cr, Ti, Zr, Al, Ga, Sc, Nb, V, W, Bi, Zn, Sn, Pt, Rh, Pd, Ru, Au, Ag, and Ir, x is 0.7 to 1, y is 0 to 0.5, and z is 0 to 0.5.

[0007] Another aspect of the present disclosure is a method for producing a composition comprising alumina, the alumina being surface-modified with a perovskite compound of formula (I), x-y A' y B 1-z B' zO3, where A is an ion of a metal selected from the group consisting of Li, Na, K, Cs, Mg, Sr, Ba, Ca, Y, La, Ce, Pr, Nd, and Gd; A' is an ion of a metal selected from the group consisting of Li, Na, K, Cs, Mg, Sr, Ba, Ca, Y, La, Ce, Pr, Nd, and Gd; B is an ion of a metal selected from the group consisting of Cu, Mn, Mo, Co, Fe, Ni, Cr, Ti, Zr, Al, Ga, Sc, Nb, V, W, Bi, Zn, Sn, Pt, Rh, Pd, Ru, Au, Ag, and Ir; B' is an ion of a metal selected from the group consisting of Cu, Mn, Mo, Co, and x is an ion of a metal selected from the group consisting of Fe, Ni, Cr, Ti, Zr, Al, Ga, Sc, Nb, V, W, Bi, Zn, Sn, Pt, Rh, Pd, Ru, Au, Ag, and Ir, and x is between 0.7 and 1, y is between 0 and 0.5, and z is between 0 and 0.5, the method comprising providing a solution comprising an organic acid, water, one or more salts of A, one or more salts of B, and optionally one or more salts of A' and / or one or more salts of B', contacting the solution with alumina to form a slurry, and heating the slurry.

[0008] Another aspect of the present disclosure is directed to a composition obtained or obtainable by the method of the above-mentioned aspect.

[0009] Another aspect of the present disclosure is a method for producing a composition comprising alumina, the alumina being surface-modified with a perovskite compound of formula (I), x-y A' y B 1-z B' zO3 (wherein A is an ion of a metal selected from the group consisting of Li, Na, K, Cs, Mg, Sr, Ba, Ca, Y, La, Ce, Pr, Nd, and Gd; A' is an ion of a metal selected from the group consisting of Li, Na, K, Cs, Mg, Sr, Ba, Ca, Y, La, Ce, Pr, Nd, and Gd; B is an ion of a metal selected from the group consisting of Cu, Mn, Mo, Co, Fe, Ni, Cr, Ti, Zr, Al, Ga, Sc, Nb, V, W, Bi, Zn, Sn, Pt, Rh, Pd, Ru, Au, Ag, and Ir; B' is an ion of a metal selected from the group consisting of Cu, Mn, Mo, Co, Fe, Ni, Cr, Ti , Zr, Al, Ga, Sc, Nb, V, W, Bi, Zn, Sn, Pt, Rh, Pd, Ru, Au, Ag, and Ir, and x is between 0.7 and 1, y is between 0 and 0.5, and z is between 0 and 0.5, the method comprising contacting alumina with one or more salts of A, one or more salts of B, and optionally one or more salts of A' and / or one or more salts of B' by incipient wetness impregnation to form an impregnated alumina, and heating the impregnated alumina.

[0010] Another aspect of the present disclosure is directed to a composition obtained or obtainable by the method of the above-mentioned aspect.

[0011] Another aspect of the present disclosure is a method for producing a composition comprising alumina, the alumina being surface-modified with a perovskite compound of formula (I), x-y A' y B 1-z B' zO3, where A is an ion of a metal selected from the group consisting of Li, Na, K, Cs, Mg, Sr, Ba, Ca, Y, La, Ce, Pr, Nd, and Gd; A' is an ion of a metal selected from the group consisting of Li, Na, K, Cs, Mg, Sr, Ba, Ca, Y, La, Ce, Pr, Nd, and Gd; B is an ion of a metal selected from the group consisting of Cu, Mn, Mo, Co, Fe, Ni, Cr, Ti, Zr, Al, Ga, Sc, Nb, V, W, Bi, Zn, Sn, Pt, Rh, Pd, Ru, Au, Ag, and Ir; B' is an ion of a metal selected from the group consisting of Cu, Mn, Mo, Co, Fe, Ni, Cr, Ti, Zr , Al, Ga, Sc, Nb, V, W, Bi, Zn, Sn, Pt, Rh, Pd, Ru, Au, Ag, and Ir, and x is between 0.7 and 1, y is between 0 and 0.5, and z is between 0 and 0.5, the method comprising providing a solution comprising one or more salts of A, one or more salts of B, and optionally one or more salts of A' and / or one or more salts of B', contacting the solution with alumina to form a slurry, spray drying the slurry to form a spray dried powder, and heating the spray dried powder.

[0012] Another aspect of the present disclosure is directed to a composition obtained or obtainable by the method of the above-mentioned aspect.

[0013] Another aspect of the invention is a method for producing a composition comprising alumina, the alumina being surface-modified with a perovskite compound of formula (I), x-y A' y B 1-z B' zO3 (wherein A is an ion of a metal selected from the group consisting of Li, Na, K, Cs, Mg, Sr, Ba, Ca, Y, La, Ce, Pr, Nd, and Gd; A' is an ion of a metal selected from the group consisting of Li, Na, K, Cs, Mg, Sr, Ba, Ca, Y, La, Ce, Pr, Nd, and Gd; B is an ion of a metal selected from the group consisting of Cu, Mn, Mo, Co, Fe, Ni, Cr, Ti, Zr, Al, Ga, Sc, Nb, V, W, Bi, Zn, Sn, Pt, Rh, Pd, Ru, Au, Ag, and Ir; B' is an ion of a metal selected from the group consisting of Cu, Mn, Mo, Co, Fe, Ni, Cr, Ti, Zr, A and x is an ion of a metal selected from the group consisting of I, Ga, Sc, Nb, V, W, Bi, Zn, Sn, Pt, Rh, Pd, Ru, Au, Ag, and Ir, x is between 0.7 and 1, y is between 0 and 0.5, and z is between 0 and 0.5, the method comprising providing an aqueous solution comprising one or more salts of A, one or more salts of B, and optionally one or more salts of A' and / or one or more salts of B', contacting the solution with alumina to form a slurry, contacting the slurry with a base, recovering a solid residue from the slurry, and heating the solid residue.

[0014] Another aspect of the present disclosure is directed to a composition obtained or obtainable by the method of the above-mentioned aspect.

[0015] Another aspect of the present disclosure relates to a catalytic article comprising a substrate, the substrate having the composition of the present invention disposed thereon.

[0016] The present invention includes an emission treatment system including the catalytic article described herein, and a method of treating an exhaust gas, the method comprising providing a catalytic article described herein and contacting the catalytic article with an exhaust gas. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 is a powder XRD pattern of 20% BaMnO3 modified alumina according to Example A6. [Diagram 2] 1 is a selected STEM elemental mapping and image of 20% La0.9MnO3 modified alumina according to Example A11. [Diagram 3] 13 is a diagram of selected STEM elemental mapping and images of 20% BaMnO3 modified alumina according to Example A6. [Figure 4] FIG. 1 shows the OSC of selected perovskite modified alumina samples. [Figure 5a] FIG. 1 shows the perturbation aged TWC light-off performance for NOx conversion of washcoated (B1) reference Pd catalyst (aged) on a single alumina support, and (B2) BaMnO3-type perovskite modified alumina support, (B3) La0.9MnO3-type perovskite modified alumina support, and (B4) Pd catalysts (aged) on SrMnO3-type perovskite modified alumina support. [Figure 5b] FIG. 1 shows perturbation aged TWC light-off performance versus CO conversion for washcoated (B1) reference Pd catalyst (aged) on a single alumina support, and (B2) BaMnO3-type perovskite modified alumina support, (B3) La0.9MnO3-type perovskite modified alumina support, and (B4) Pd catalysts (aged) on SrMnO3-type perovskite modified alumina support. [Figure 5c] FIG. 1 shows perturbation aged TWC light-off performance versus THC conversion for washcoated (B1) reference Pd catalyst (aged) on a single alumina support, and (B2) BaMnO3-type perovskite modified alumina support, (B3) La0.9MnO3-type perovskite modified alumina support, and (B4) Pd catalysts (aged) on SrMnO3-type perovskite modified alumina support. [Figure 6a]FIG. 1 shows the perturbation aged TWC light-off performance for NOx conversion of washcoated (B5) reference Rh catalyst (aged) on a single alumina support, and (B6) BaMnO3-type perovskite modified alumina support, (B7) La0.9MnO3-type perovskite modified alumina support, (B8) La0.9Mn0.7Zr0.3O3-type perovskite modified alumina support, and (B9) Rh catalyst on La0.9Mn0.9Zr0.1O3-type perovskite modified alumina support (aged). [Figure 6b] FIG. 1 shows the perturbation aged TWC light-off performance for CO conversion of washcoated (B5) reference Rh catalyst (aged) on a single alumina support, (B6) BaMnO3-type perovskite modified alumina support, (B7) La0.9MnO3-type perovskite modified alumina support, (B8) La0.9Mn0.7Zr0.3O3-type perovskite modified alumina support, and (B9) Rh catalyst on La0.9Mn0.9Zr0.1O3-type perovskite modified alumina support (aged). [Figure 6c] FIG. 1 shows perturbation aged TWC light-off performance versus THC conversion for washcoated (B5) reference Rh catalyst (aged) on a single alumina support, (B6) BaMnO3-type perovskite modified alumina support, (B7) La0.9MnO3-type perovskite modified alumina support, (B8) La0.9Mn0.7Zr0.3O3-type perovskite modified alumina support, and (B9) Rh catalyst (aged) on La0.9Mn0.9Zr0.1O3-type perovskite modified alumina support. [Figure 7a]Wash-coated (B10) reference Pd fully loaded catalyst (aged), and (B11) 10% BaMnO3 modified alumina type perovskite modified alumina support, (B12) 20% BaMnO3 modified alumina type perovskite modified alumina support, (B13) 20% La0.9MnO3 modified alumina type perovskite modified alumina support, (B14) 10% La0.9Mn0.7Zr0.3O3 modified alumina type perovskite modified alumina support. FIG. 13 shows the perturbation aged TWC light-off performance for NOx conversion of Pd catalysts (aged) having modified alumina supports, (B15) 10% La0.9Mn0.9Zr0.1O3 modified alumina type perovskite modified alumina supports, and (B16) 10% LaFeO3 modified alumina type perovskite modified alumina supports, and (B17) reference Pd catalyst with 130 g / ft3 Pd loading. [Figure 7b] The wash-coated (B10) reference Pd fully loaded catalyst (aged), and (B11) 10% BaMnO3 modified alumina type perovskite modified alumina support, (B12) 20% BaMnO3 modified alumina type perovskite modified alumina support, (B13) 20% La0.9MnO3 modified alumina type perovskite modified alumina support, (B14) 10% La0.9Mn0.7Zr0.3O3 modified alumina type perovskite modified alumina support, (B15) 10% La0.9Mn0.7Zr0.3O3 modified alumina type perovskite modified alumina support, (B16) 10% La0.9Mn0.7Zr0.3O3 modified alumina type perovskite modified alumina support, (B17) 10% La0.9Mn0.7Zr0.3O3 modified alumina type perovskite modified alumina support, (B18) 10% La0.9Mn0.7Zr0.3O3 modified alumina type perovskite modified alumina support, (B19) 10% La0.9Mn0.7Zr0.3O3 modified alumina type perovskite modified alumina support, (B20) 10% La0.9Mn0.7Zr0.3O3 modified alumina type perovskite modified alumina support, (B21) 10% La0.9Mn0.7Zr0.3O3 modified alumina type perovskite modified alumina support, (B22) 10% La0.9Mn0.7Zr0.3O3 modified alumina type perovskite modified alumina support, (B23) 10% La0.9Mn0.7Zr0.3O3 modified alumina type perovskite modified alumina support, ( FIG. 1 shows the perturbation aged TWC light-off performance for CO conversion of Pd catalysts (aged) having a 10% LaFeO3 modified alumina type perovskite modified alumina support, (B15) a 10% LaFeO3 modified alumina type perovskite modified alumina support, and (B16) a 10% LaFeO3 modified alumina type perovskite modified alumina support, and (B17) a reference Pd catalyst with 130 g / ft3 Pd loading. [Figure 7c]The wash-coated (B10) reference Pd fully loaded catalyst (aged), and (B11) 10% BaMnO3 modified alumina type perovskite modified alumina support, (B12) 20% BaMnO3 modified alumina type perovskite modified alumina support, (B13) 20% La0.9MnO3 modified alumina type perovskite modified alumina support, (B14) 10% La0.9Mn0.7Zr0.3O3 modified alumina type perovskite modified alumina support, (B15) 10% La0.9Mn0.7Zr0.3O3 modified alumina type perovskite modified alumina support, (B16) 10% La0.9Mn0.7Zr0.3O3 modified alumina type perovskite modified alumina support, (B17) 10% La0.9Mn0.7Zr0.3O3 modified alumina type perovskite modified alumina support, (B18) 10% La0.9Mn0.7Zr0.3O3 modified alumina type perovskite modified alumina support, (B19) 10% La0.9Mn0.7Zr0.3O3 modified alumina type perovskite modified alumina support, (B20) 10% La0.9Mn0.7Zr0.3O3 modified alumina type perovskite modified alumina support, (B21) 10% La0.9Mn0.7Zr0.3O3 modified alumina type perovskite modified alumina support, (B22) 10% La0.9Mn0.7Zr0.3O3 modified alumina type perovskite modified alumina support, (B23) 10% La0.9Mn0.7Zr0.3O3 modified alumina type perovskite modified alumina support, ( FIG. 1 shows the perturbation aged TWC light-off performance for THC conversion of Pd catalysts (aged) having a 10% LaFeO3 modified alumina support, (B15) a 10% LaFeO3 modified alumina type perovskite modified alumina support, and (B16) a 10% LaFeO3 modified alumina type perovskite modified alumina support, and (B17) a reference Pd catalyst with 130 g / ft3 Pd loading. [Figure 8a] FIG. 1 shows the perturbation aged TWC light-off performance for NOx conversion of washcoated (B18) reference Rh (aged) fully formulated catalyst, and (B19) 10% La0.9Mn0.7Zr0.3O3 modified alumina type perovskite modified alumina support, (B20) 10% La0.9Mn0.9Zr0.1O3 modified alumina type perovskite modified alumina support, and (B21) 10% La0.9Mn0.9Zr0.1O3 modified alumina type perovskite modified alumina support with Rh catalyst (aged). [Figure 8b] FIG. 1 shows perturbation aged TWC light-off performance for CO conversion of washcoated (B18) reference Rh (aged) fully formulated catalyst, and (B19) 10% La0.9Mn0.7Zr0.3O3 modified alumina type perovskite modified alumina support, (B20) 10% La0.9Mn0.9Zr0.1O3 modified alumina type perovskite modified alumina support, and (B21) 10% La0.9Mn0.9Zr0.1O3 modified alumina type perovskite modified alumina support with Rh catalyst (aged). [Figure 8c]FIG. 1 shows the perturbation aged TWC light-off performance in terms of TWC conversion of washcoated (B18) reference Rh (aged) fully formulated catalyst, and (B19) 10% La0.9Mn0.7Zr0.3O3 modified alumina type perovskite modified alumina support, (B20) 10% La0.9Mn0.9Zr0.1O3 modified alumina type perovskite modified alumina support, and (B21) 10% La0.9Mn0.9Zr0.1O3 modified alumina type perovskite modified alumina support with Rh catalyst (aged). [Figure 9a] FIG. 13 shows the perturbation aged TWC light-off performance for NOx conversion of washcoated (B22) reference Pt (aged) fully formulated catalyst and Pt catalysts (aged) with (B23) 10% BaMnO3 modified alumina support, (B24) 20% BaMnO3 modified alumina support, (B25) 10% La0.9MnO3 modified alumina support, (B26) 20% La0.9MnO3 modified alumina support, (B27) 10% CaMnO3 modified alumina support, (B28) 20% CaMnO3 modified alumina support, and (B29) 10% LaFeO3 modified alumina support. [Figure 9b] FIG. 13 shows perturbation aged TWC light-off performance for CO conversion of washcoated (B22) reference Pt (aged) fully formulated catalyst and Pt catalysts (aged) with (B23) 10% BaMnO3 modified alumina support, (B24) 20% BaMnO3 modified alumina support, (B25) 10% La0.9MnO3 modified alumina support, (B26) 20% La0.9MnO3 modified alumina support, (B27) 10% CaMnO3 modified alumina support, (B28) 20% CaMnO3 modified alumina support, and (B29) 10% LaFeO3 modified alumina support. [Figure 9c]FIG. 13 shows perturbation aged TWC light-off performance for THC conversion of washcoated (B22) reference Pt (aged) fully formulated catalyst and Pt catalysts (aged) with (B23) 10% BaMnO3 modified alumina support, (B24) 20% BaMnO3 modified alumina support, (B25) 10% La0.9MnO3 modified alumina support, (B26) 20% La0.9MnO3 modified alumina support, (B27) 10% CaMnO3 modified alumina support, (B28) 20% CaMnO3-modified alumina support, and (B29) 10% LaFeO3 modified alumina support. [Figure 10] FIG. 1 shows cumulative NOx emissions during vehicle testing for aged (B30) reference PdRh fully formulated catalyst versus (B31) 10% BaMnO3 (IWI) modified alumina, (B32) 10% BaMnO3 (SD) modified alumina, and (B33) PdRh catalysts (aged) with 20% BaMnO3 (IWI) modified alumina. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] The present invention aims to address at least some of the problems associated with the prior art, or at least to provide a commercially acceptable alternative solution.

[0019] In a first aspect, the present invention provides a composition comprising alumina, the alumina being surface-modified with a perovskite compound of formula (I): Formula (I) is A x-y A' y B 1-z B' z O3 (in the formula, A is an ion of a metal selected from the group consisting of Li, Na, K, Cs, Mg, Sr, Ba, Ca, Y, La, Ce, Pr, Nd, and Gd; A' is an ion of a metal selected from the group consisting of Li, Na, K, Cs, Mg, Sr, Ba, Ca, Y, La, Ce, Pr, Nd, and Gd; B is an ion of a metal selected from the group consisting of Cu, Mn, Mo, Co, Fe, Ni, Cr, Ti, Zr, Al, Ga, Sc, Nb, V, W, Bi, Zn, Sn, Pt, Rh, Pd, Ru, Au, Ag, and Ir; B' is an ion of a metal selected from the group consisting of Cu, Mn, Mo, Co, Fe, Ni, Cr, Ti, Zr, Al, Ga, Sc, Nb, V, W, Bi, Zn, Sn, Pt, Rh, Pd, Ru, Au, Ag, and Ir; x is 0.7 to 1; y is between 0 and 0.5; and z is 0 to 0.5.

[0020] Each aspect or embodiment defined in this specification may be combined with any other aspect(s) or embodiment(s) unless expressly indicated otherwise. In particular, any feature indicated as being preferred or advantageous may be combined with any other feature(s) indicated as being preferred or advantageous.

[0021] Alumina (Al2O3) is the "classic" support material used in exhaust treatment catalysts such as TWC. Alumina is known to provide high surface area for the active PGM metals and promoter species. Alumina is also more thermally robust than other mixed oxide supports to the harsh TWC operating conditions.

[0022] Surprisingly, the inventors of the present invention have found that by surface modifying such alumina supports with perovskite-type compounds, the alumina can be imparted with OSC properties, while the alumina otherwise has minimal OSC properties, and still retain most of its surface area under thermal aging conditions. This can also advantageously facilitate improved promotion of the supported PGM species, if present, supported on the modified support (the inventive composition) to obtain improved TWC conversion.

[0023] As used herein, the term "surface modified" may include, for example, that the perovskite compound is supported or coated on the alumina. That is, the perovskite compound is physically and / or chemically attached or supported on the surface of the alumina, preferably in a (highly) dispersed form. The term "surface modified" does not include a mere physical blend or mixture of the bulk perovskite compound and the alumina. In this sense, the perovskite compound is not in bulk form. For example, it is believed that under extreme oxidation and / or aging conditions, aluminates may form between the perovskite compound and the alumina to aid in the bonding of the perovskite compound to the surface of the alumina. That is, aluminates may be located at the interface between the alumina and the perovskite compound, for example, between the alumina and the perovskite compound. As used herein, the term "surface modified" may also include that the particle size of the perovskite compound is smaller than the particle size of the alumina. As used herein, the term "surface modified" can also include the alumina being in bulk form and the perovskite compound being dispersed on the surface and / or within the pores of the bulk alumina.

[0024] Without being bound by theory, it is believed that the perovskite compound can be stabilized by alumina when providing such surface-modified alumina, where the alumina is surface-modified with the perovskite compound of formula (I). Thus, the disadvantages of bulk perovskite compounds, such as their low surface area to volume ratio and their lack of stability at exhaust gas catalyst operating temperatures, can be mitigated while imparting their advantageous OSC properties to the alumina support. That is, the alumina phase can provide high surface area and act as a support to stabilize the perovskite nanocrystalline phase (e.g., from sintering) in thermal aging conditions. Synergistic interactions between the dispersed perovskite and the support species (e.g., PGM and promoter) can also occur, which can result in improved TWC performance. In addition to the promotion effect, the perovskite itself can also exhibit intrinsic activity for the TWC reaction, promoting PGM performance, which can allow for a potential reduction in PGM loading. There is a desire in the art to reduce the amount of PGM loading, especially for cost reasons.

[0025] Such advantages cannot be realized by the use of bulk phase perovskite compounds in catalysts for treating exhaust gases, particularly TWC catalysts.

[0026] Thus, advantageously, the compositions of the present invention may be used in place of existing support materials, such as where alumina is used as a support material in known catalyst articles, to provide OSC properties to a catalyst or even to replace existing OSC support materials, such as ceria-zirconia support materials, which may provide additional and / or improved OSC properties. For example, it has been shown that replacing conventional support materials with the compositions of the present invention can significantly reduce the T50 (temperature at which 50% conversion is achieved) of conversion for NOx, CO and / or THC (total hydrocarbon) reduction.

[0027] In summary, the inventors have surprisingly been able to harness the advantages of perovskite-type compounds OSCs for use in emissions treatment catalysts, while at least partially mitigating the disadvantages and instability of such compounds in bulk form at the operating temperatures of catalysts, e.g., TWCs.

[0028] As used herein, the term "perovskite" has its ordinary meaning in the art, i.e., perovskite-type compounds can refer to a class of compounds that have a crystal structure similar to or a distorted version of CaTiO.

[0029] The composition and / or the perovskite compound of formula (I) may contain unavoidable impurities, typically less than 1 wt%, preferably less than 0.5 wt%, more preferably less than 0.1 wt%.

[0030] Preferably, the composition consists of alumina, which is surface modified with a perovskite compound of formula (I).

[0031] Preferably, A and / or A' are ions of a metal selected from the group consisting of Ca, Mg, Ba, Ca, Y, La, Sr, Nd, Ce and Gd, more preferably, A and / or A' are ions of a metal selected from the group consisting of Ca, Ba, La and Sr. Preferably, B and / or B' are ions of a metal selected from the group consisting of Mn, Co, Fe, Zr and Ni, more preferably, B and / or B' are ions of a metal selected from the group consisting of Mn, Zr and Fe. Preferably, B and / or B' are doped with a PGM element including one or more of Pt, Pd and Rh, i.e., B and / or B' may further comprise, in addition to the preferred metals listed above, ions of a metal selected from the group consisting of Pt, Pd and Rh. Such compositions may be particularly suitable for use in applications described herein, for example, for use in TWCs.

[0032] Preferably, x is from 0.8 to 1, more preferably from 0.9 to 1, or even more preferably from 0.7 to 0.9, more preferably from 0.8 to 0.9. Preferably, y is from 0 to 0.3, more preferably from 0 to 0.2, more preferably from greater than 0 to 0.2. Preferably, z is from 0 to 0.4, more preferably from 0 to 0.3, even more preferably from greater than 0 to 0.2. Such compositions may be particularly suitable for use in the applications described herein, for example for use in TWCs.

[0033] Preferably, y > 0. Preferably, z > 0. Such compositions may be particularly suitable for use in the applications described herein, such as for use in TWCs.

[0034] In an alternative preferred embodiment, z is 0. In an alternative preferred embodiment, y is 0. Preferably, y=z=0. However, when y>0, z can be 0, and when z>0, y can be 0.

[0035] Preferably, when y=z=0, A is La and B is Mn. In an alternative preferred embodiment, when y=z=0, A is Ca and B is Mn. In an alternative preferred embodiment, when y=z=0, A is La and B is Fe. In an alternative preferred embodiment, when y=z=0, A is Ba and B is Mn. In an alternative preferred embodiment, when y=z=0, A is Sr and B is Mn. In an alternative preferred embodiment, when y=z=0, A is Ba and B is Fe. In an alternative preferred embodiment, when y=z=0, A is Ca and B is Fe. In an alternative preferred embodiment, when y=z=0, A is Sr and B is Fe. Such compositions may be particularly suitable for use in applications described herein, for example, in TWCs.

[0036] Preferably, x is 1. Such compositions may be particularly suitable for use in the applications described herein, such as for use in TWCs.

[0037] Preferably, the alumina comprises gamma alumina. Gamma alumina is known in the art. More preferably, the alumina consists of gamma alumina. In an alternative preferred embodiment, the alumina comprises theta alumina. Theta alumina is known in the art. More preferably, the alumina consists of theta alumina. Preferably, the alumina comprises or consists of gamma alumina and / or theta alumina. Preferably, the alumina is doped. Suitable dopants are known in the art. For example, preferably, the alumina is doped with one or more oxides of La, Ba, Sr, Mg, Mn, Y, Nd, Pr, Ce, Zr, Ti, Fe, Cu, Co, Zn, Si, and Ni, more preferably La, or La and Mg. Such doped aluminas can be particularly useful as support materials. Preferably, the dopant is present in the alumina in an amount of from 0.001% to 20% by weight, more preferably from 0.5% to 10% by weight, based on the total weight of the alumina.

[0038] Preferably, the composition comprises 1-50 wt.%, preferably 5-30 wt.%, more preferably 5-25 wt.%, even more preferably 10-20 wt.% of the perovskite compound, based on the total weight of the perovskite compound and the alumina. The perovskite compound may, for example, be highly dispersed on the alumina. Such a ratio of the perovskite compound may provide a particularly stable composition with improved OSC properties.

[0039] Preferably, the alumina is further surface modified with a mixed oxide complex of formula (I), which may occur when phases other than the perovskite phase of formula (I) are present, for example due to incomplete formation of the perovskite phase during synthesis or the formation of aluminates at the interface between the perovskite compound and the alumina.

[0040] In a further aspect, the present invention provides a method for producing a composition comprising alumina, the alumina being surface modified with a perovskite compound of formula (I), Formula (I) is A x-y A' y B 1-z B' z O3 (in the formula, A is an ion of a metal selected from the group consisting of Li, Na, K, Cs, Mg, Sr, Ba, Ca, Y, La, Ce, Pr, Nd, and Gd; A' is an ion of a metal selected from the group consisting of Li, Na, K, Cs, Mg, Sr, Ba, Ca, Y, La, Ce, Pr, Nd, and Gd; B is an ion of a metal selected from the group consisting of Cu, Mn, Mo, Co, Fe, Ni, Cr, Ti, Zr, Al, Ga, Sc, Nb, V, W, Bi, Zn, Sn, Pt, Rh, Pd, Ru, Au, Ag, and Ir; B' is an ion of a metal selected from the group consisting of Cu, Mn, Mo, Co, Fe, Ni, Cr, Ti, Zr, Al, Ga, Sc, Nb, V, W, Bi, Zn, Sn, Pt, Rh, Pd, Ru, Au, Ag, and Ir; x is 0.7 to 1; y is between 0 and 0.5; z is 0 to 0.5), and the method is providing a solution comprising an organic acid, water, one or more salts of A, one or more salts of B, and optionally one or more salts of A' and / or one or more salts of B'; contacting the solution with alumina to form a slurry; and heating the slurry.

[0041] Such a method can be envisaged as a (modified) Pechini method.

[0042] As used herein, the term "slurry" can include a liquid containing insoluble material, e.g., insoluble particles. The slurry is typically stirred, more typically for at least 10 minutes, more typically for at least 30 minutes, and even more typically for at least 1 hour. Increasing the contact time and / or stirring time can increase the dispersion of the perovskite compound on the alumina.

[0043] Contacting the solution with alumina may typically involve adding alumina, for example in powder form, to the solution. However, contacting the solution with alumina may also involve combining the solution with a slurry containing alumina, for example alumina powder in water. The contacting step is not particularly limited in this respect.

[0044] In some preferred embodiments, the solution further comprises an organic solvent, preferably ethylene glycol, however, more preferably the solution does not comprise an inorganic solvent, i.e. the solution is preferably an aqueous solution.

[0045] The one or more salts preferably include acetate, nitrate, oxynitrate, chloride, ammonium nitrate, hydroxide, oxalate and / or citrate, more preferably acetate, nitrate and / or oxynitrate.

[0046] Preferably, heating the slurry includes a first step of heating the slurry to a temperature of 150-350°C to form a gel. As used herein, the term "gel" may include, for example, a colloid in a more solid form than a sol or a thick viscous slurry. Without being bound by theory, this relatively low temperature heating may promote evaporation of at least a portion of the water in the slurry to thicken the slurry and / or promote the formation of perovskite compounds on the alumina. More preferably, heating the slurry includes a first step of heating the slurry to a temperature of 200-300°C, for example, 250-300°C to form a gel.

[0047] Preferably, heating the slurry includes calcination, preferably after the heating step mentioned above (i.e., including a first step of heating the slurry to a temperature of 150-350°C to form a gel). As used herein, the term "calcination" may include a heat treatment process in the absence or limited supply of air or oxygen to cause pyrolysis or thermal transformation. Typically, however, calcination in this context involves heating in air in an oven. Preferably, calcination involves heating at a temperature of 300°C-500°C, preferably 350°C-450°C, for 1-10 hours, preferably 3-6 hours. In an alternative or additional preferred embodiment, calcination involves heating at a temperature of 600-1000°C, preferably 700-900°C, for 1-8 hours, preferably 2-5 hours. More preferably, the calcination comprises a first calcination step involving heating at a temperature of 300-500°C, preferably 350-450°C, for 1-10 hours, preferably 3-6 hours, followed by a second calcination step involving heating at a temperature of 600-1000°C, preferably 700-900°C, for 1-8 hours, preferably 2-5 hours. Without being bound by theory, it is believed that the first low temperature calcination step can promote the formation of mixed oxides of the perovskite precursor metals, i.e., from the precursor salts, and then the second high temperature calcination step can promote the formation of a dense perovskite structure supported on alumina (i.e., surface modified alumina). It is emphasized that the perovskite compound is not in bulk form but is supported on the surface of the alumina.

[0048] Preferably, the organic acid comprises a carboxylic acid, more preferably a di- or tricarboxylic acid. The organic acid preferably comprises or even consists of citric acid, tannic acid, humic acid, succinic acid, EDTA, DTPA and / or other chelating agents, more preferably citric acid, tannic acid, humic acid, succinic acid, EDTA and / or DTPA, even more preferably citric acid.

[0049] Preferably, the composition produced by the method of this aspect is the composition of the first aspect described herein.

[0050] In a further aspect, the present invention provides a composition obtained or obtainable by the method of the above aspect.

[0051] Surprisingly, the inventors of the present invention have found that by surface modifying an alumina support with a perovskite type compound to provide such a composition, the alumina can be imparted with OSC properties, which otherwise may have minimal OSC properties, whilst still retaining most of its surface area under thermal aging conditions, which may also advantageously facilitate improved promotion of the supported PGM species, if present, supported on the modified support (the inventive composition), to obtain improved TWC conversion.

[0052] Without being bound by theory, it is believed that the perovskite compound can be stabilized by alumina when providing such surface-modified alumina, where the alumina is surface-modified with the perovskite compound of formula (I). Thus, the disadvantages of bulk perovskite compounds, such as their low surface area to volume ratio and their lack of stability at exhaust gas catalyst operating temperatures, can be mitigated while imparting their advantageous OSC properties to the alumina support. That is, the alumina phase can provide high surface area and act as a support to stabilize the perovskite nanocrystalline phase (e.g., from sintering) in thermal aging conditions. Synergistic interactions between the dispersed perovskite and the support species (e.g., PGM and promoter) can also occur, which can result in improved TWC performance. In addition to the promotion effect, the perovskite itself can also exhibit intrinsic activity for the TWC reaction, promoting PGM performance, which can allow for a potential reduction in PGM loading. There is a desire in the art to reduce the amount of PGM loading, especially for cost reasons.

[0053] Such advantages cannot be realized by the use of bulk phase perovskite compounds in catalysts for treating exhaust gases, particularly TWC catalysts.

[0054] Thus, advantageously, the compositions of the present invention may be used in place of existing support materials, such as where alumina is used as a support material in known catalyst articles, to provide OSC properties to a catalyst or even to replace existing OSC support materials, such as ceria-zirconia support materials, which may provide additional and / or improved OSC properties. For example, it has been shown that replacing conventional support materials with the compositions of the present invention can significantly reduce the T50 (temperature at which 50% conversion is achieved) of conversion for NOx, CO and / or THC (total hydrocarbon) reduction.

[0055] In summary, the inventors have surprisingly been able to harness the advantages of OSCs of perovskite-type compounds for use in emissions treatment catalysts, while at least partially mitigating the disadvantages and instability of such compounds in bulk form at the operating temperatures of the catalyst, e.g., TWC. In other words, the same advantages apply to the composition of this embodiment as to the composition of the first embodiment.

[0056] In a further aspect, the present invention provides a method for producing a composition comprising alumina, the alumina being surface modified with a perovskite compound of formula (I), Formula (I) is A x-y A' y B 1-z B' z O3 (in the formula, A is an ion of a metal selected from the group consisting of Li, Na, K, Cs, Mg, Sr, Ba, Ca, Y, La, Ce, Pr, Nd, and Gd; A' is an ion of a metal selected from the group consisting of Li, Na, K, Cs, Mg, Sr, Ba, Ca, Y, La, Ce, Pr, Nd, and Gd; B is an ion of a metal selected from the group consisting of Cu, Mn, Mo, Co, Fe, Ni, Cr, Ti, Zr, Al, Ga, Sc, Nb, V, W, Bi, Zn, Sn, Pt, Rh, Pd, Ru, Au, Ag, and Ir; B' is an ion of a metal selected from the group consisting of Cu, Mn, Mo, Co, Fe, Ni, Cr, Ti, Zr, Al, Ga, Sc, Nb, V, W, Bi, Zn, Sn, Pt, Rh, Pd, Ru, Au, Ag, and Ir; x is 0.7 to 1; y is between 0 and 0.5; z is 0 to 0.5), and the method is contacting alumina with A, B, and optionally A' and / or B' by incipient wetness impregnation using one or more salts of A, one or more salts of B, and optionally one or more salts of A' and / or one or more salts of B' to form an impregnated alumina; and heating the impregnated alumina.

[0057] Incipient wetness impregnation (IW or IWI) is a technique well known in the art. Those skilled in the art will be able to perform a suitable incipient wetness impregnation method without further instruction.

[0058] Contacting alumina with A, B, and optionally A' and / or B' by incipient wetness impregnation using one or more salts of A, one or more salts of B, and optionally one or more salts of A' and / or one or more salts of B' can include, for example, impregnating alumina with A, B, and optionally A' and / or B' by incipient wetness impregnation using one or more salts of A, one or more salts of B, and optionally one or more salts of A' and / or one or more salts of B'.

[0059] The one or more salts preferably include acetate, nitrate, oxynitrate, chloride, ammonium nitrate, hydroxide, oxalate and / or citrate, more preferably acetate, nitrate and / or oxynitrate.

[0060] Preferably, heating the impregnated alumina comprises a first step of drying the impregnated alumina at a temperature of 50 to 150° C., preferably 50 to 100° C., for 1 hour to 24 hours, preferably 6 hours to 12 hours.

[0061] Preferably, heating the impregnated alumina comprises calcining, preferably after the heating step described above (i.e. comprising a first step of drying the impregnated alumina at a temperature of 50-150°C, preferably 50-100°C, for 1 hour to 24 hours, preferably 6 hours to 12 hours). Preferably, the calcination comprises heating at a temperature of 300°C to 500°C, preferably 350°C to 450°C, for 1 hour to 10 hours, preferably 3 hours to 6 hours. In an alternative or additional preferred embodiment, the calcination comprises heating at a temperature of 600-1000°C, preferably 700-900°C, for 1 hour to 8 hours, preferably 2 hours to 5 hours. More preferably, the calcination comprises a first calcination step comprising heating at a temperature of 300-500°C, preferably 350-450°C, for 1-10 hours, preferably 3-6 hours, followed by a second calcination step comprising heating at a temperature of 600-1000°C, preferably 700-900°C, for 1-8 hours, preferably 2-5 hours. Without being bound by theory, it is believed that the first low temperature calcination step can promote the formation of mixed oxides of the perovskite precursor metals, i.e., from the precursor salts, and then the second high temperature calcination step can promote the formation of a dense perovskite structure supported on the alumina (i.e., surface modified alumina). It is emphasized that the perovskite compound can be supported on the surface of the alumina not in bulk form but in a dispersed state.

[0062] Preferably, the composition produced by the method of this aspect is the composition of the first aspect described herein.

[0063] In a further aspect, the present invention provides a composition obtained or obtainable by the method of the above aspect.

[0064] Surprisingly, the inventors of the present invention have found that by surface modifying an alumina support with a perovskite type compound to provide such a composition, the alumina can be imparted with OSC properties, which otherwise may have minimal OSC properties, whilst still retaining most of its surface area under thermal aging conditions, which may also advantageously facilitate improved promotion of the supported PGM species, if present, supported on the modified support (the inventive composition), to obtain improved TWC conversion.

[0065] Without being bound by theory, it is believed that the perovskite compound can be stabilized by alumina when providing such surface-modified alumina, where the alumina is surface-modified with the perovskite compound of formula (I). Thus, the disadvantages of bulk perovskite compounds, such as their low surface area to volume ratio and their lack of stability at exhaust gas catalyst operating temperatures, can be mitigated while imparting their advantageous OSC properties to the alumina support. That is, the alumina phase can provide high surface area and act as a support to stabilize the perovskite nanocrystalline phase (e.g., from sintering) in thermal aging conditions. Synergistic interactions between the dispersed perovskite and the support species (e.g., PGM and promoter) can also occur, which can result in improved TWC performance. In addition to the promotion effect, the perovskite itself can also exhibit intrinsic activity for the TWC reaction, promoting PGM performance, which can allow for a potential reduction in PGM loading. There is a desire in the art to reduce the amount of PGM loading, especially for cost reasons.

[0066] Such advantages cannot be realized by the use of bulk phase perovskite compounds in catalysts for treating exhaust gases, particularly TWC catalysts.

[0067] Thus, advantageously, the compositions of the present invention may be used in place of existing support materials, such as where alumina is used as a support material in known catalyst articles, to provide OSC properties to a catalyst or even to replace existing OSC support materials, such as ceria-zirconia support materials, which may provide additional and / or improved OSC properties. For example, it has been shown that replacing conventional support materials with the compositions of the present invention can significantly reduce the T50 (temperature at which 50% conversion is achieved) of conversion for NOx, CO and / or THC (total hydrocarbon) reduction.

[0068] In summary, the inventors have surprisingly been able to harness the advantages of OSCs of perovskite-type compounds for use in emissions treatment catalysts, while at least partially mitigating the disadvantages and instability of such compounds in bulk form at the operating temperatures of the catalyst, e.g., TWC. In other words, the same advantages apply to the composition of this embodiment as to the composition of the first embodiment.

[0069] In a further aspect, the present invention provides a method for producing a composition comprising alumina, the alumina being surface modified with a perovskite compound of formula (I), Formula (I) is A x-y A' y B 1-z B' z O3 (in the formula, A is an ion of a metal selected from the group consisting of Li, Na, K, Cs, Mg, Sr, Ba, Ca, Y, La, Ce, Pr, Nd, and Gd; A' is an ion of a metal selected from the group consisting of Li, Na, K, Cs, Mg, Sr, Ba, Ca, Y, La, Ce, Pr, Nd, and Gd; B is an ion of a metal selected from the group consisting of Cu, Mn, Mo, Co, Fe, Ni, Cr, Ti, Zr, Al, Ga, Sc, Nb, V, W, Bi, Zn, Sn, Pt, Rh, Pd, Ru, Au, Ag, and Ir; B' is an ion of a metal selected from the group consisting of Cu, Mn, Mo, Co, Fe, Ni, Cr, Ti, Zr, Al, Ga, Sc, Nb, V, W, Bi, Zn, Sn, Pt, Rh, Pd, Ru, Au, Ag, and Ir; x is 0.7 to 1; y is between 0 and 0.5; z is 0 to 0.5), and the method is providing a solution comprising one or more salts of A, one or more salts of B, and optionally one or more salts of A' and / or one or more salts of B'; contacting the solution with alumina to form a slurry; spray drying the slurry to form a spray dried powder; and heating the spray dried powder.

[0070] Spray drying is a well-known technique in the art, and it is believed that one of ordinary skill in the art would be able to carry out a suitable spray drying method without further instruction.

[0071] Contacting the solution with alumina may typically involve adding alumina, for example in powder form, to the solution. However, contacting the solution with alumina may also involve combining the solution with a slurry containing alumina, for example alumina powder in water. The contacting step is not particularly limited in this respect.

[0072] The one or more salts preferably include acetate, nitrate, oxynitrate, chloride, ammonium nitrate, hydroxide, oxalate and / or citrate, more preferably acetate, nitrate and / or oxynitrate.

[0073] Preferably, the solution is an aqueous solution.

[0074] Preferably, heating the spray dried powder comprises calcining. Preferably, the calcining comprises heating at a temperature of 300°C to 500°C, preferably 350°C to 450°C, for 1 to 10 minutes, preferably 3 to 6 hours. In an alternative or additional preferred embodiment, the calcining comprises heating at a temperature of 600 to 1000°C, preferably 700 to 900°C, for 1 to 8 hours, preferably 2 to 5 hours. More preferably, the calcining comprises a first calcination step comprising heating at a temperature of 300 to 500°C, preferably 350 to 450°C, for 1 to 10 hours, preferably 3 to 6 hours, the first calcination step being followed by a second calcination step comprising heating at a temperature of 600 to 1000°C, preferably 700 to 900°C, for 1 to 8 hours, preferably 2 to 5 hours. Without wishing to be bound by theory, it is believed that a first low temperature calcination step can promote the formation of mixed oxides of the perovskite precursor metals, i.e., from the precursor salts, and then a second high temperature calcination step can promote the formation of a dense perovskite structure supported on the alumina (i.e., surface modified alumina). It is emphasized that the perovskite compounds are not in bulk form, but are supported on the surface of the alumina.

[0075] Preferably, the inlet temperature of the spray drying is from 100° C. to 300° C., more preferably from 150° C. to 250° C. Inlet temperature is a well-known term in the field of spray drying.

[0076] Preferably, the composition produced by the method of this aspect is the composition of the first aspect described herein.

[0077] In a further aspect, the present invention provides a composition obtained or obtainable by the method of the above aspect.

[0078] Surprisingly, the inventors of the present invention have found that by surface modifying an alumina support with a perovskite type compound to provide such a composition, the alumina can be imparted with OSC properties, which otherwise may have minimal OSC properties, whilst still retaining most of its surface area under thermal aging conditions, which may also advantageously facilitate improved promotion of the supported PGM species, if present, supported on the modified support (the inventive composition), to obtain improved TWC conversion.

[0079] Without being bound by theory, it is believed that the perovskite compound can be stabilized by alumina when providing such surface-modified alumina, where the alumina is surface-modified with the perovskite compound of formula (I). Thus, the disadvantages of bulk perovskite compounds, such as their low surface area to volume ratio and their lack of stability at exhaust gas catalyst operating temperatures, can be mitigated while imparting their advantageous OSC properties to the alumina support. That is, the alumina phase can provide high surface area and act as a support to stabilize the perovskite nanocrystalline phase (e.g., from sintering) in thermal aging conditions. Synergistic interactions between the dispersed perovskite and the support species (e.g., PGM and promoter) can also occur, which can result in improved TWC performance. In addition to the promotion effect, the perovskite itself can also exhibit intrinsic activity for the TWC reaction, promoting PGM performance, which can allow for a potential reduction in PGM loading. There is a desire in the art to reduce the amount of PGM loading, especially for cost reasons.

[0080] Such advantages cannot be realized by the use of bulk phase perovskite compounds in catalysts for treating exhaust gases, particularly TWC catalysts.

[0081] Thus, advantageously, the compositions of the present invention may be used in place of existing support materials, such as where alumina is used as a support material in known catalyst articles, to provide OSC properties to a catalyst or even to replace existing OSC support materials, such as ceria-zirconia support materials, which may result in additional and / or improved OSC properties. For example, replacing a conventional support material with the compositions of the present invention may result in reduced NO x , T of conversion for CO and / or THC (total hydrocarbon) reduction 50 It has been shown that the temperature at which 50% conversion is achieved can be significantly reduced.

[0082] In summary, the inventors have surprisingly been able to harness the advantages of OSCs of perovskite-type compounds for use in emissions treatment catalysts, while at least partially mitigating the disadvantages and instability of such compounds in bulk form at the operating temperatures of the catalyst, e.g., TWC. In other words, the same advantages apply to the composition of this embodiment as to the composition of the first embodiment.

[0083] In a further aspect, the present invention provides a method for producing a composition comprising alumina, the alumina being surface modified with a perovskite compound of formula (I), Formula (I) is A x-y A' y B 1-z B' z O3 (in the formula, A is an ion of a metal selected from the group consisting of Li, Na, K, Cs, Mg, Sr, Ba, Ca, Y, La, Ce, Pr, Nd, and Gd; A' is an ion of a metal selected from the group consisting of Li, Na, K, Cs, Mg, Sr, Ba, Ca, Y, La, Ce, Pr, Nd, and Gd; B is an ion of a metal selected from the group consisting of Cu, Mn, Mo, Co, Fe, Ni, Cr, Ti, Zr, Al, Ga, Sc, Nb, V, W, Bi, Zn, Sn, Pt, Rh, Pd, Ru, Au, Ag, and Ir; B' is an ion of a metal selected from the group consisting of Cu, Mn, Mo, Co, Fe, Ni, Cr, Ti, Zr, Al, Ga, Sc, Nb, V, W, Bi, Zn, Sn, Pt, Rh, Pd, Ru, Au, Ag, and Ir; x is 0.7 to 1; y is between 0 and 0.5; z is 0 to 0.5), and the method is providing an aqueous solution comprising one or more salts of A, one or more salts of B, and optionally one or more salts of A' and / or one or more salts of B'; contacting the solution with alumina to form a slurry; contacting the slurry with a base; recovering a solid residue from the slurry; and heating the solid residue.

[0084] Contacting the solution with alumina may typically involve adding alumina, for example in powder form, to the solution. However, contacting the solution with alumina may also involve combining the solution with a slurry containing alumina, for example alumina powder in water. The contacting step is not particularly limited in this respect.

[0085] The one or more salts preferably include acetate, nitrate, oxynitrate, chloride, ammonium nitrate, hydroxide, oxalate and / or citrate, more preferably acetate, nitrate and / or oxynitrate.

[0086] The method includes contacting the slurry with a base. Preferably, contacting the slurry with a base includes contacting the slurry with a solution comprising a base, preferably an aqueous solution comprising a base. Such a method may be referred to as a "co-precipitation" method. Without being bound by theory, it is believed that the addition of base may result in the precipitation of A, A', B and / or B' cations on the alumina support. The method may further include filtering and / or washing the alumina after the addition of base (i.e., having the precipitated contents thereon) and prior to heating the solid residue.

[0087] Recovering the solid residue from the slurry can include filtering the slurry to obtain the solid residue. As used herein, the term "solid residue" can include, for example, filter cakes. Such filter cakes are well known in the art.

[0088] Preferably, heating the solid residue comprises a first step of drying the solid residue at a temperature of 50-150° C., preferably 50-100° C., for 1 hour to 24 hours, preferably 6 hours to 12 hours.

[0089] Preferably, heating the solid residue comprises a calcination, preferably after the heating step mentioned above (i.e. comprising a first step of drying the solid residue at a temperature of 50-150°C, preferably 50-100°C for 1 hour to 24 hours, preferably 6 hours to 12 hours). Preferably, the calcination comprises heating at a temperature of 300°C to 500°C, preferably 350°C to 450°C for 1 hour to 10 hours, preferably 3 hours to 6 hours. In an alternative or additional preferred embodiment, the calcination comprises heating at a temperature of 600-1000°C, preferably 700-900°C for 1 hour to 8 hours, preferably 2 hours to 5 hours. More preferably, the calcination comprises a first calcination step comprising heating at a temperature of 300-500°C, preferably 350-450°C, for 1-10 hours, preferably 3-6 hours, followed by a second calcination step comprising heating at a temperature of 600-1000°C, preferably 700-900°C, for 1-8 hours, preferably 2-5 hours. Without being bound by theory, it is believed that the first low temperature calcination step can promote the formation of mixed oxides of the perovskite precursor metals, i.e., from the precursor salts, and then the second high temperature calcination step can promote the formation of a dense perovskite structure supported on the alumina (i.e., surface modified alumina). It is emphasized that the perovskite compound can be supported on the surface of the alumina not in bulk form but in a dispersed state.

[0090] Preferably, the base comprises ammonium hydroxide.

[0091] Preferably, recovering the solid residue from the slurry comprises filtering the slurry to obtain the solid residue and washing the solid residue with water, preferably with excess water.

[0092] Preferably, the composition produced by the method of this aspect is the composition of the first aspect described herein.

[0093] In a further aspect, the present invention provides a composition obtained or obtainable by the method of the above aspect.

[0094] Surprisingly, the inventors of the present invention have found that by surface modifying an alumina support with a perovskite type compound to provide such a composition, the alumina can be imparted with OSC properties, which otherwise may have minimal OSC properties, whilst still retaining most of its surface area under thermal aging conditions, which may also advantageously facilitate improved promotion of the supported PGM species, if present, supported on the modified support (the inventive composition), to obtain improved TWC conversion.

[0095] Without being bound by theory, it is believed that the perovskite compound can be stabilized by alumina when providing such surface-modified alumina, where the alumina is surface-modified with the perovskite compound of formula (I). Thus, the disadvantages of bulk perovskite compounds, such as their low surface area to volume ratio and their lack of stability at exhaust gas catalyst operating temperatures, can be mitigated while imparting their advantageous OSC properties to the alumina support. That is, the alumina phase can provide high surface area and act as a support to stabilize the perovskite nanocrystalline phase (e.g., from sintering) in thermal aging conditions. Synergistic interactions between the dispersed perovskite and the support species (e.g., PGM and promoter) can also occur, which can result in improved TWC performance. In addition to the promotion effect, the perovskite itself can also exhibit intrinsic activity for the TWC reaction, promoting PGM performance, which can allow for a potential reduction in PGM loading. There is a desire in the art to reduce the amount of PGM loading, especially for cost reasons.

[0096] Such advantages cannot be realized by the use of bulk phase perovskite compounds in catalysts for treating exhaust gases, particularly TWC catalysts.

[0097] Thus, advantageously, the compositions of the present invention may be used in place of existing support materials, such as where alumina is used as a support material in known catalyst articles, to provide OSC properties to a catalyst or even to replace existing OSC support materials, such as ceria-zirconia support materials, which may result in additional and / or improved OSC properties. For example, replacing a conventional support material with the compositions of the present invention may result in reduced NO x , T of conversion for CO and / or THC (total hydrocarbon) reduction 50 It has been shown that the temperature at which 50% conversion is achieved can be significantly reduced.

[0098] In summary, the inventors have surprisingly been able to harness the advantages of OSCs of perovskite-type compounds for use in emissions treatment catalysts, while at least partially mitigating the disadvantages and instability of such compounds in bulk form at the operating temperatures of the catalyst, e.g., TWC. In other words, the same advantages apply to the composition of this embodiment as to the composition of the first embodiment.

[0099] In a further aspect, the present invention provides a catalytic article comprising a substrate having a composition described herein disposed thereon.

[0100] As used herein, the term "catalyst article" may include an article on or within which a catalyst is supported. The article may take the form of, for example, a honeycomb monolith, or a filter, such as a wall-flow filter or a flow-through filter.

[0101] The term "substrate" as used herein can include, for example, ceramic or metal honeycombs, or filter blocks, such as wall-flow or flow-through filters. Substrates can include ceramic monolith substrates. Substrates can vary in their material composition, size and configuration, cell shape and density, and wall thickness. Suitable substrates are known in the art.

[0102] The term "disposed on" in the context of this embodiment can include both having a composition disposed directly on the substrate, i.e., without intervening materials, and / or having a composition disposed indirectly on the substrate, i.e., with intervening materials. If the substrate is porous, the term "disposed on" can also include having a composition disposed therein, e.g., within the pores of the substrate, i.e., the composition is disposed on and / or within. In other words, the compositions described herein may be incorporated into one or more washcoat regions, zones, or layers disposed on the substrate in any order. Such substrate-washcoat formulations are generally well known in the art. As used herein, the term "washcoat" is well known in the art and generally refers to an adherent coating that is applied to a substrate during the production of a catalyst.

[0103] Preferably, the catalyst article is for treating exhaust gases. Preferably, the catalyst article comprises a three-way catalyst (TWC), more preferably the catalyst article is a TWC.

[0104] Preferably, platinum group metals (PGMs) are supported on the composition. The PGMs may be supported on the surface and / or in the pores of the alumina. The PGMs may also be supported on the perovskite compound. The PGMs may also be located at the interface between the alumina and the perovskite compound supported on the alumina. Without wishing to be bound by theory, it is believed that the presence of the perovskite compound may further promote the catalytic activity of the PGM and increase the resistance of the PGM nanoparticles to sintering. PGM sintering may reduce the catalytic activity of the PGM. These benefits may be facilitated by charge transfer and / or oxygen transfer between the perovskite and PGM phases, resulting in improved PGM stability. For example, if the supported PGM particles have a small particle size, in extreme cases, the particles may interact / adsorb the PGMs in / onto the perovskite framework under oxidizing conditions, which may reduce the likelihood of PGM sintering. The perovskite may at least promote the formation of PGM oxides. As used herein, the term PGM encompasses one or more platinum group metals selected from ruthenium, rhodium, palladium, osmium, iridium, and platinum. Preferably, the PGM comprises Pt, Pd, Rh, or mixtures or alloys thereof. Such metals may be particularly suitable for performing three-way catalysis. The PGM may be in the form of an alloy.

[0105] Preferably, the catalyst article is for use in an emission treatment system. Preferably, the catalyst article is for three-way catalysis.

[0106] Preferably, the catalyst article has a surface area of ​​1 g / in 3 ~3g / in 3 The washcoat loading may be

[0107] Preferably, the substrate comprises a wall-flow filter substrate. In an alternative preferred embodiment, the substrate comprises a flow-through substrate.

[0108] Preferably, the catalyst article comprises a bottom layer of support material having rhodium thereon and a top layer of support material having palladium thereon. In an alternative preferred embodiment, the catalyst article comprises a bottom layer of support material having palladium thereon and a top layer of support material having rhodium thereon. The support material may comprise any suitable known support material. However, preferably, the support material comprises a composition as described herein. That is, the support material present in the bottom layer and / or the top layer may comprise a composition as described herein.

[0109] When present, the catalyst article preferably has a surface area of ​​2 g / ft 3 ~15g / ft 3 of rhodium, more preferably 3g / ft 3 ~10g / ft 3 When present, the catalyst article preferably contains 20 g / ft 3 ~200g / ft 3 of palladium, more preferably 30 g / ft 3 ~150g / ft 3 When present, the catalytic article preferably contains 2 g / ft 3 ~200g / ft 3 of platinum, preferably 10 g / ft 3 ~100g / ft 3 Contains platinum.

[0110] In a further aspect, the present invention provides an emission treatment system comprising the catalytic article described herein. Preferably, the emission treatment system is for a gasoline engine. Preferably, the gasoline engine operates under stoichiometric conditions.

[0111] In a further aspect, the present invention provides a method of treating an exhaust gas, the method comprising providing a catalytic article as described herein and contacting the catalytic article with an exhaust gas. Preferably, the exhaust gas is from a gasoline engine. Preferably, the gasoline engine is operated under stoichiometric conditions.

[0112] The invention will now be described with reference to the following non-limiting examples. EXAMPLES

[0113] A. Synthesis example Example A1: Synthesis of 10 wt% BaMnO3 modified alumina by Pechini method 1. In a 1000 mL beaker, n (M total ):n(citric acid):n(ethylene glycol)=2:3:90 (wherein, M total Calculated amounts of citric acid and ethylene glycol were dissolved in the molar ratio of 0.1 to 0.25 moles of 100% Ba and 1 to 100% Mn, respectively, of the total metal cations (Ba and Mn) in the perovskite formula.

[0114] 2. An appropriate amount of DI water was added, followed by continuous stirring, to produce a clear solution.

[0115] 3. The calculated amounts of barium acetate (20.4 g) and manganese acetate tetrahydrate (19.6 g) were added and stirred continuously for 1 hour.

[0116] 4. The required amount of stabilized alumina (192.2 g) was added. This was mixed for 1 hour with continuous stirring.

[0117] 5. The resulting slurry was slowly heated to 275°C and continuously stirred until a gel was formed.

[0118] 6. After the gel was cooled to room temperature, it was transferred to a large crucible and covered with alumina foil (having holes on the cover).

[0119] 7. Low-temperature calcination was carried out in stagnant air at 400°C for 4 hours (heating rate 10°C / min).

[0120] 8. After the sample was cooled, it was transferred to a smaller crucible and calcined at high temperature at 800°C for 4 hours (heating rate 10°C / min).

[0121] Example A2: Synthesis of 10 wt% BaMnO3 modified alumina by aqueous method 1. In a 1000 mL beaker, n (M total ):n(citric acid)=2:3 (wherein, M total The calculated amount of citric acid was dissolved in 500 mL of DI water in a molar ratio of 0.1 to 0.5 (wherein Mn is the total metal cation (Ba and Mn) in the perovskite formula). This was stirred continuously until a thick slurry was formed.

[0122] 2. The calculated amounts of barium acetate (20.4 g) and manganese acetate tetrahydrate (19.6 g) were added and stirred continuously for 1 hour.

[0123] 3. The required amount of stabilized alumina (192.2 g) was added. This was mixed for 1 hour with continuous stirring.

[0124] 4. The resulting slurry was heated to 275°C and stirred continuously until a gel was formed.

[0125] 5. After the gel was cooled to room temperature, it was transferred to a large crucible and covered with alumina foil (having holes on the cover).

[0126] 6. Low-temperature calcination was carried out in stagnant air at 400°C for 4 hours (heating rate 10°C / min).

[0127] 7. After the sample was cooled, it was transferred to a smaller crucible and calcined at high temperature at 800°C for 4 hours (heating rate 10°C / min).

[0128] Example A3: Synthesis of 10 wt% BaMnO3 modified alumina by incipient wetness impregnation method 1.10 wt% equivalent of BaMn (1:1 molar ratio) was impregnated onto stabilized alumina (192.2 g) powder with a mixed solution of barium acetate (20.4 g) and manganese acetate tetrahydrate (19.6 g) using incipient wetness impregnation.

[0129] 2. The resulting impregnated alumina was dried at 80°C for 1 hour and mixed periodically to prevent wicking.

[0130] 3. Low-temperature calcination was carried out in stagnant air at 400°C for 4 hours, followed by high-temperature calcination at 800°C for 4 hours (heating rate 10°C / min).

[0131] Example A4: Synthesis of 10 wt% BaMnO3 modified alumina by spray drying method 1. A solution of barium acetate (107.3 g) and manganese acetate tetrahydrate (102.9 g) was prepared and mixed for 1 hour until the Ba / Mn precursor was completely dissolved.

[0132] 2. Stabilized alumina (1009 g) was added to the above solution at a target solids content of 30% with mechanical mixing for at least 1 hour to make a slurry.

[0133] 3. The slurry was spray dried, ensuring adequate mixing of the slurry during the entire spray drying process.

[0134] 4. The spray dried powder was collected and calcined in a static oven at 400°C / 4h followed by 800°C / 4h.

[0135] Examples A5 to A19 The synthesis procedures for Examples A5 to A19 were similar to those for Examples A1 to A4, and the amounts of the main precursors are summarized in Table 1 below.

[0136] [Table 1] Note: I. Synthetic procedure similar to Example A1 using different amounts of metal precursors and alumina (Pechini method) II. Similar synthetic procedure as in Example A2 (aqueous method) using different amounts of metal precursors and alumina. III. Similar synthesis procedure as in Example A3 (incipient wetness impregnation, IWI) with different amounts of metal precursor and alumina. IV. Similar synthesis procedure to Example A4 (spray drying, SD) using different amounts of metal precursor and alumina. Barium acetate. b. Manganese acetate tetrahydrate. c. Lanthanum nitrate hexahydrate. d. Zirconium oxynitrate (solution form). e.Calcium nitrate tetrahydrate. f. Iron nitrate nonahydrate. g. Strontium nitrate.

[0137] B. Catalyst preparation example Reference Example B1: 3 wt% Pd / alumina washcoat catalyst 1.3 wt % Pd (as a palladium nitrate solution) was impregnated into the alumina powder using incipient wetness impregnation.

[0138] 2. The impregnated alumina was dried at 80°C for 1 hour, mixed periodically to prevent wicking, and then calcined at 500°C for 30 minutes in still air.

[0139] A slurry was prepared with DI water and appropriate amounts of binders and thickeners for a final batch solids content of 3.22%. The slurry was vigorously mixed in a VWR vortex mixer until homogenous.

[0140] 4. A 1x3 inch ceramic substrate core was coated aiming for an addition of 1.2 inches from the inlet end and then allowed to air cure and dry.

[0141] 5. The bricks were fired in a static oven at 500°C for 30 minutes.

[0142] Example B2: 3 wt% Pd / 10% BMO modified alumina washcoat catalyst 1.3 wt % Pd (as palladium nitrate solution) was impregnated onto 10% BaMnO3 modified alumina powder (Example A1) using incipient wetness impregnation.

[0143] 2. The impregnated alumina was dried at 80°C for 1 hour, mixed periodically to prevent wicking, and then calcined at 500°C for 30 minutes in still air.

[0144] A slurry was prepared with DI water and appropriate amounts of binders and thickeners for a final batch solids content of 3.22%. The slurry was vigorously mixed in a VWR vortex mixer until homogenous.

[0145] 4. A 1x3 inch ceramic substrate core was coated aiming for an addition of 1.2 inches from the inlet end and then allowed to air cure and dry.

[0146] 5. The bricks were fired in a static oven at 500°C for 30 minutes.

[0147] Examples B3 to B9 The catalyst preparation procedures of Examples B3 to B14 were similar to those of Examples B1 and B2, and the amounts of main precursors are summarized in Table 2 below.

[0148] [Table 2]

[0149] Reference Example B10: Fully formulated single layer Pd washcoat 1. (Pd loading 100g / ft 3 A solution was prepared using the required amount of Pd nitrate (having the formula:

[0150] 2.1g / in 3 of stabilized alumina powder and 1g / in 3 of CZO material was added and mixed for 1 hour.

[0151] 3.300g / ft 3 of barium sulfate was added and mixed for at least 1 hour.

[0152] 4. After adding the appropriate amount of binder, mix for 1 hour.

[0153] 5. The solids content was adjusted to 30%, thickener was added, and then mixed overnight.

[0154] A 6.1×3 inch ceramic substrate core was coated 50-55% from the inlet end, allowed to dry by air curing, and then coated 50-55% of the dose length from the outlet end.

[0155] 7. The bricks were fired in a static oven at 500°C for 30 minutes.

[0156] Example B11: Fully formulated single layer Pd washcoat with 10% BMO modified alumina 1. (Pd loading 100g / ft 3 A solution was prepared using the required amount of Pd nitrate (having the formula:

[0157] 2.1g / in 3 10% BaMnO3 modified alumina powder (Example A3) and 1 g / in 3 of CZO material was added and mixed for 1 hour.

[0158] 3.300g / ft 3 of barium sulfate was added and mixed for at least 1 hour.

[0159] 4. After adding the appropriate amount of binder, mix for 1 hour.

[0160] 5. The solids content was adjusted to 30%, thickener was added, and then mixed overnight.

[0161] A 6.1×3 inch ceramic substrate core was coated 50-55% from the inlet end, allowed to dry by air curing, and then coated 50-55% of the dose length from the outlet end.

[0162] 7. The bricks were fired in a static oven at 500°C for 30 minutes.

[0163] Examples B12 to B17 The catalyst preparation procedures of Examples B12 to B17 are similar to those of Examples B10 and B11, but the Pd loading and type of modified alumina are listed in Table 3 below.

[0164] [Table 3]

[0165] Reference Example B18: Fully Formulated Single Layer Rh Wash Coat 1. (Rh loading: 4.8 g / ft 3 A solution was prepared using the required amount of Rh nitrate.

[0166] 2. Slurry of unground stabilized alumina (0.5 g / in 3 ) was prepared and mixed until homogenous (at least 30 minutes).

[0167] 3. Ammonium was added dropwise until the pH reached 7.0-7.5.

[0168] 4. The slurry was mixed for 1 hour to allow the rhodium to precipitate throughout the washcoat.

[0169] 5. Ground stabilized alumina (0.1 g / in 3 ) and CZO (0.7g / in 3 ) was added and then mixed for 30 minutes until homogenous.

[0170] 6. After adding the appropriate amount of binder, mix for 30 minutes and adjust the solid content to 23%.

[0171] 7. Thickener was added targeting approximately 1.0-1.2% by weight on a water basis, then mixed overnight.

[0172] An 8.1×3 inch ceramic substrate core was coated 50-55% from the inlet end, dried by air curing, and then coated 50-55% of the dose length from the outlet end.

[0173] 9. The bricks were fired in a static oven at 500°C for 30 minutes.

[0174] Example B19: Fully formulated single layer Rh washcoat with 10% LMO modified alumina 1. (Rh loading: 4.8 g / ft 3 A solution was prepared using the required amount of Rh nitrate.

[0175] 2. Unground 10% La 0.9 A slurry of MnO modified alumina was prepared (Example A9, 0.5 g / in 3 ) and mixed until homogenous (at least 30 minutes).

[0176] 3. Ammonium was added dropwise until a pH of 7.0-7.5 was reached.

[0177] 4. The slurry was mixed for 1 hour to allow the rhodium to precipitate throughout the washcoat.

[0178] 5. Ground stabilized alumina (0.1 g / in 3 ) and CZO (0.7g / in 3 ) was added and then mixed for 30 minutes until homogenous.

[0179] 6. After adding the appropriate amount of binder, mix for 30 minutes and adjust the solid content to 23%.

[0180] 7. Thickener was added targeting approximately 1.0-1.2% by weight on a water basis, then mixed overnight.

[0181] An 8.1×3 inch ceramic substrate core was coated 50-55% from the inlet end, dried by air curing, and then coated 50-55% of the dose length from the outlet end.

[0182] 9. The bricks were fired in a static oven at 500°C for 30 minutes.

[0183] Examples B20 and B21 The catalyst preparation procedures of Examples B20 and B21 are similar to those of Examples B18 and B19, and the Rh loading and the type of modified alumina are listed in Table 4 below.

[0184] [Table 4]

[0185] Reference Example B22: Fully compounded single layer Pt washcoat 1. (Pt loading 20g / ft 3 A solution was prepared with the required amount of Pt nitrate (having the formula:

[0186] 2. Stabilized alumina (1g / in 3 ) and CZO(1g / in 3 ) was added to the batch.

[0187] 3. Adjust the pH to 5-6.6 with ammonia and mix for at least 1 hour.

[0188] 4. Solids adjusted to target (suggested around 30%).

[0189] 5. The appropriate amount of thickener was added and then mixed overnight.

[0190] A single-addition target was coated 1.2 inches from the inlet end of a 6.1×3 inch ceramic substrate core.

[0191] 7. Fire the bricks in a static oven at 500°C / 30min.

[0192] Example B23: Fully Formulated Single Layer Pt Washcoat with 10% BMO Modified Alumina 1. (Pt loading 20g / ft 3 A solution was prepared with the required amount of Pt nitrate (having the formula:

[0193] 2. 10% BaMnO3 modified alumina (A3, 1g / in 3 ) and CZO(1g / in 3 ) was added to the batch.

[0194] 3. Adjust the pH to 5-6.6 with ammonia and mix for at least 1 hour.

[0195] 4. Solids adjusted to target (suggested around 30%).

[0196] 5. An appropriate amount of thickener was added and allowed to stand overnight.

[0197] A single-addition target was coated 1.2 inches from the inlet end of a 6.1×3 inch ceramic substrate core.

[0198] 7. The bricks were fired in a static oven at 500°C / 30 min.

[0199] Examples B24 to B29 The catalyst preparation procedures of Examples B24 to B29 are similar to those of Examples B22 and B23, but the Pt loadings and types of modified alumina are listed in Table 5 below.

[0200] [Table 5]

[0201] Reference Example B30: Fully Formulated Dual Layer PdRh Washcoat Bottom layer: 1. (Pd loading 80g / ft 3 A solution of the required amount of Pd nitrate was prepared.

[0202] 2. Unground stabilized alumina 1g / in 3 and crushed CZO 0.5g / in 3 ) slurry was added and mixed for at least 2 hours.

[0203] 3. (250g / ft 3 Barium acetate (having Ba) was added and mixed for 1 hour.

[0204] 4. The slurry was deagglomerated at 4000-5000 rpm for 5 minutes.

[0205] 5. Thickener was added at 0.3-0.6% of all the water and then mixed overnight.

[0206] A 6.1×3 inch ceramic substrate core was coated 50-55% from the inlet end, dried by air curing, and then coated an add-on length of 50-55% from the outlet end.

[0207] 7. The bricks were fired in a static oven at 500°C / 30 min.

[0208] Top layer: 1. (Rh loading: 3.8 g / ft 3 A solution of the required amount of Rh nitrate was prepared.

[0209] 2. Ground stabilized alumina (0.8 g / in 3 ) slurry was added and mixed for at least 1 hour.

[0210] 3. NH4OH was added to bring the pH to 6-7 and mixed for at least 1 hour.

[0211] 4. Slurry of ground CZO (0.8 g / in 3 ) was added and mixed for at least 1 hour.

[0212] 5. Thickener was added and stirred overnight.

[0213] A 6.1×3 inch ceramic substrate core was coated 50-55% from the inlet end, dried by air curing, and then coated 50-55% of the add-on length from the outlet end.

[0214] 7. The bricks were fired in a static oven at 500°C / 30 min.

[0215] Examples B31 to B33 The catalyst preparation procedures of Examples B31-B33 are similar to Example B30, but have the same top layer formulation and different bottom layer formulations by replacing the unmodified alumina with modified alumina, as listed in Table 6 below.

[0216] [Table 6]

[0217] C. Results and Testing FIG. 1 shows the powder XRD pattern of 20% BaMnO3 modified alumina according to Example A6. The hexagonal polytype of BaMnO3 perovskite structure was detected. In general, the high surface area of ​​alumina (approximately 200 m 2 Due to the low surface area (µm / g) and relatively low loading of perovskite synthesized on alumina (10%-20%), the perovskite phase is usually highly dispersed and may be below the detection limit of XRD.

[0218] 2 and 3 show, respectively, (A11) 20% La 0.9 Selected STEM elemental mapping and images of (A) MnO3 modified alumina and (B) 20%BaMnO3 modified alumina are shown. Universal distribution of A-site and B-site elements of perovskite on the alumina support was observed in both samples. High resolution STEM images also showed lattice spacing at the particle surface / edges, suggesting the formation or ordered crystalline structure on the alumina support.

[0219] Figure 4 shows the OSC of selected perovskite-modified alumina samples. Alumina supports do not inherently exhibit OSC properties. After surface modification with perovskite phase, prominent OSC features are introduced into the alumina supports. During OSC measurements, the powder samples were pre-oxidized at each temperature, followed by flowing CO through the samples, in which case CO was converted to CO2 by oxygen species donated from the powder samples. Thus, the total OSC of the solid samples corresponds to the amount of CO2 produced per gram of sample. The low-temperature (≦350°C) OSC of these modified alumina samples reached as high as 0.1–0.2 mmol of CO2 produced / g, while the high-temperature (≧500°C) OSC of these samples reached as high as 0.2–0.35 mmol of CO2 produced / g.

[0220] 5a, 5b and 5c show the TWC light-off performance (NOx, CO and THC conversion) of the Pd catalysts supported on single alumina or modified alumina, respectively. In particular, the figures show the TWC light-off performance (NOx, CO and THC conversion) of the washcoated (B1) reference Pd catalyst on single alumina support (aged), as well as (B2) BaMnO3-type perovskite modified alumina support, (B3) La 0.9 Figure 1 shows the perturbation aged TWC light-off performance for (a) NO conversion, (b) CO conversion, and (c) THC conversion for (B1) MnO3-type perovskite modified alumina support, and (B2) Pd catalyst (aged) on SrMnO3-type perovskite modified alumina support. Reaction conditions: with rich pretreatment, 150-700°C, λ=0.96-1.04, GHSV=200,000 hours. -1 The modified supports were synthesized by the Pechini method. Compared to the reference catalyst, the improvement of TWC conversion was observed for the perovskite modified supports, especially for NO x It was expressed as conversion.

[0221] 6a, 6b and 6c show the TWC light-off performance (NOx, CO and THC conversion) of the Rh catalysts supported on single alumina or modified alumina, respectively. In particular, these figures show the TWC light-off performance (NOx, CO and THC conversion) of the washcoated (B5) reference Rh catalyst (aged) on a single alumina support, and (B6) BaMnO3-type perovskite modified alumina support, (B7) La 0.9 MnO3-type perovskite modified alumina support, (B8)La 0.9 Mn 0.7 Zr 0.3 O3-type perovskite modified alumina support, and (B9) La 0.9 Mn 0.9 Zr 0.1 Perturbation aged TWC light-off performance for (a) NO conversion, (b) CO conversion, and (c) THC conversion of Rh catalyst (aged) on O3-type perovskite modified alumina support. Reaction conditions: with rich pretreatment, 150-700°C, λ=0.96-1.04, GHSV=200,000 hours. -1The modified supports were synthesized by the incipient wetness impregnation method. Compared to the reference catalyst, a significant improvement in TWC conversion was shown for the perovskite modified supports.

[0222] 7a, 7b and 7c respectively show the TWC light-off performance (NOx, CO and THC conversion) of the fully-formulated Pd catalyst with perovskite-modified support. In particular, the figures show the TWC light-off performance (NOx, CO and THC conversion) of the washcoated (B10) reference Pd fully-formulated catalyst (aged), and (B11) 10% BaMnO3 modified alumina type perovskite-modified alumina support, (B12) 20% BaMnO3 modified alumina type perovskite-modified alumina support, (B13) 20% La 0.9 MnO3 modified alumina type perovskite modified alumina support, (B14) 10% La 0.9 Mn 0.7 Zr 0.3 O3 modified alumina type perovskite modified alumina support, (B15) 10% La 0.9 Mn 0.9 Zr 0.1 O3 modified alumina type perovskite modified alumina support, and (B16) Pd catalyst having 10% LaFeO3 modified alumina type perovskite modified alumina support, and 130 g / ft 3 Figure 1 shows the perturbation aged TWC light-off performance for (a) NO conversion, (b) CO conversion, and (c) THC conversion of the (B17) reference Pd catalyst (aged) with Pd loading. Reaction conditions: with rich pretreatment, 150-700°C, λ=0.96-1.04, GHSV=200,000 hours. -1 . Reference Pd(100g / ft 3 A significant improvement in TWC conversion was shown with the perovskite modified supports compared to the Pd loading of 130 g / ft. The T50 (temperature at which 50% conversion is achieved) and T75 (temperature at which 50% conversion is achieved) of catalysts with several perovskite-alumina compositions were 130 g / ft. 3 The overall TWC activity was comparable to that of the Pd catalyst at the loading. The order of activity was 20% BaMnO3-alumina > 20% La. 0.9MnO3-alumina>10%LaFeO3-alumina>10%BaMnO3-alumina>10%La 0.9 Mn 0.9 Zr 0.1 O3-Alumina>10%La 0.9 Mn 0.7 Zr 0.3 O3-Alumina>(100g / ft 3 In accordance with the sequence of Pd catalysts with reference Pd).

[0223] 8a, 8b and 8c show the TWC light-off performance (NOx, CO and THC conversion) of the fully-formulated Rh catalysts with perovskite-modified supports, respectively. In particular, the figures show the TWC light-off performance (NOx, CO and THC conversion) of the washcoated (B18) reference Rh (aged) fully-formulated catalyst, and (B19) 10% La 0.9 MnO3 modified alumina type perovskite modified alumina support, (B20) 10% La 0.9 Mn 0.7 Zr 0.3 O3 modified alumina type perovskite modified alumina support, and (B21) 10% La 0.9 Mn 0.9 Zr 0.1 Figure 1 shows the perturbation aged TWC light-off performance for (a) NO conversion, (b) CO conversion, and (c) THC conversion of Rh catalyst (aged) with O3-modified alumina-type perovskite-modified alumina support. Reaction conditions: with rich pretreatment, 150-700°C, λ=0.96-1.04, GHSV=200,000 hours. -1 Compared to the reference Rh catalyst, the selected perovskite modified supports showed a significant improvement in TWC conversion.

[0224] 9a, 9b and 9c show the TWC light-off performance of fully-formulated Pt catalysts with perovskite-modified supports, respectively. In particular, the figures show the TWC light-off performance of washcoated (B22) reference Pt (aged) fully-formulated catalyst, as well as (B23) 10% BaMnO3 modified alumina support, (B24) 20% BaMnO3 modified alumina support, (B25) 10% La 0.9 MnO3 modified alumina support, (B26) 20%La0.9 MnO3 modified alumina support, (B27) 10% CaMnO3 modified alumina support, (B28) 20% CaMnO3 modified alumina support, and (B29) 10% LaFeO 3- Figure 1 shows the perturbation aged TWC light-off performance for (a) NO conversion, (b) CO conversion, and (c) THC conversion of a Pt catalyst (aged) with modified alumina support. Reaction conditions: with rich pretreatment, 150-700°C, λ=0.96-1.04, GHSV=200,000 hours. -1 Compared to the reference Pt catalyst, a significant improvement in TWC conversion was shown with the selected perovskite modified supports according to the following order: Pt with 10% CaMnO3-alumina>20% Pt with CaMnO3-alumina>20% Pt with BaMnO3-alumina>20% La 0.9 Pt>10%La with MnO3-alumina 0.9 Pt with MnO3-alumina > 10% Pt with BaMnO3-alumina > 10% Pt with LaFeO3-alumina > Reference Pt.

[0225] Figure 10 shows the cumulative NOx emissions of the fully formulated Pd-Rh catalysts with perovskite-modified supports. In particular, Figure 10 shows the cumulative NOx emissions during vehicle testing of the aged (B30) reference PdRh fully formulated catalyst versus (B31) 10% BaMnO3 (IWI) modified alumina, (B32) 10% BaMnO3 (SD) modified alumina, and (B33) PdRh catalysts with 20% BaMnO3 (IWI) modified alumina (aged). Compared to the reference Pd-Rh catalyst, the selected perovskite-modified supports showed significant improvement in NOx conversion.

[0226] The foregoing detailed description has been provided for purposes of explanation and illustration and is not intended to limit the scope of the appended claims. Many variations of the presently preferred embodiments described herein will be apparent to those of ordinary skill in the art and remain within the scope of the appended claims and their equivalents.

Claims

1. A composition comprising alumina, the alumina being surface-modified with a perovskite compound of formula (I), Formula (I) is A ｘ－ｙ A' ｙ B １－ｚ B' ｚ O ３ (In the formula, A is an ion of a metal selected from the group consisting of Li, Na, K, Cs, Mg, Sr, Ba, Ca, Y, La, Ce, Pr, Nd, and Gd; A' is an ion of a metal selected from the group consisting of Li, Na, K, Cs, Mg, Sr, Ba, Ca, Y, La, Ce, Pr, Nd, and Gd; B is an ion of a metal selected from the group consisting of Cu, Mn, Mo, Co, Fe, Ni, Cr, Ti, Zr, Al, Ga, Sc, Nb, V, W, Bi, Zn, Sn, Pt, Rh, Pd, Ru, Au, Ag, and Ir; B' is an ion of a metal selected from the group consisting of Cu, Mn, Mo, Co, Fe, Ni, Cr, Ti, Zr, Al, Ga, Sc, Nb, V, W, Bi, Zn, Sn, Pt, Rh, Pd, Ru, Au, Ag, and Ir; x is 0.7 to 1; y is 0 to 0.5; and z is 0 to 0.

5.

2. 2. The composition of claim 1, wherein A and / or A' are ions of a metal selected from the group consisting of Ca, Mg, Ba, Ca, Y, La, Sr, Nd, Ce, and Gd.

3. 3. The composition of claim 2, wherein A and / or A' are ions of a metal selected from the group consisting of Ca, Ba, La, and Sr.

4. 3. The composition of claim 1, wherein B and / or B' are ions of a metal selected from the group consisting of Mn, Co, Fe, Zr and Ni.

5. 3. The composition of claim 1, wherein B and / or B' are ions of a metal selected from the group consisting of Mn, Zr, and Fe.

6. 3. The composition of claim 1 or 2, wherein the alumina is doped, preferably the alumina is doped with one or more oxides of La, Ba, Sr, Mg, Mn, Y, Nd, Pr, Ce, Zr, Ti, Fe, Cu, Co, Zn, Si and Ni, preferably La, or La and Mg.

7. 3. The composition according to claim 1, wherein the composition comprises 1 to 50 wt. %, preferably 5 to 30 wt. %, of the perovskite compound, based on the total weight of the perovskite compound and the alumina.

8. 1. A method for producing a composition comprising alumina, the alumina being surface-modified with a perovskite compound of formula (I), Formula (I) is A ｘ－ｙ A' ｙ B １－ｚ B' ｚ O ３ (In the formula, A is an ion of a metal selected from the group consisting of Li, Na, K, Cs, Mg, Sr, Ba, Ca, Y, La, Ce, Pr, Nd, and Gd; A' is an ion of a metal selected from the group consisting of Li, Na, K, Cs, Mg, Sr, Ba, Ca, Y, La, Ce, Pr, Nd, and Gd; B is an ion of a metal selected from the group consisting of Cu, Mn, Mo, Co, Fe, Ni, Cr, Ti, Zr, Al, Ga, Sc, Nb, V, W, Bi, Zn, Sn, Pt, Rh, Pd, Ru, Au, Ag, and Ir; B' is an ion of a metal selected from the group consisting of Cu, Mn, Mo, Co, Fe, Ni, Cr, Ti, Zr, Al, Ga, Sc, Nb, V, W, Bi, Zn, Sn, Pt, Rh, Pd, Ru, Au, Ag, and Ir; x is 0.7 to 1; y is 0 to 0.5; z is 0 to 0.5, and the method comprises: providing a solution comprising an organic acid, water, one or more salts of A, one or more salts of B, and optionally one or more salts of A' and / or one or more salts of B'; contacting the solution with alumina to form a slurry; and heating the slurry.

9. 1. A method for producing a composition comprising alumina, the alumina being surface-modified with a perovskite compound of formula (I), Formula (I) is A ｘ－ｙ A' ｙ B １－ｚ B' ｚ O ３ (In the formula, A is an ion of a metal selected from the group consisting of Li, Na, K, Cs, Mg, Sr, Ba, Ca, Y, La, Ce, Pr, Nd, and Gd; A' is an ion of a metal selected from the group consisting of Li, Na, K, Cs, Mg, Sr, Ba, Ca, Y, La, Ce, Pr, Nd, and Gd; B is an ion of a metal selected from the group consisting of Cu, Mn, Mo, Co, Fe, Ni, Cr, Ti, Zr, Al, Ga, Sc, Nb, V, W, Bi, Zn, Sn, Pt, Rh, Pd, Ru, Au, Ag, and Ir; B' is an ion of a metal selected from the group consisting of Cu, Mn, Mo, Co, Fe, Ni, Cr, Ti, Zr, Al, Ga, Sc, Nb, V, W, Bi, Zn, Sn, Pt, Rh, Pd, Ru, Au, Ag, and Ir; x is 0.7 to 1; y is 0 to 0.5; z is 0 to 0.5, and the method comprises: contacting alumina with A, B, and optionally A' and / or B' by incipient wetness impregnation using one or more salts of A, one or more salts of B, and optionally one or more salts of A' and / or one or more salts of B' to form an impregnated alumina; and heating the impregnated alumina.

10. 1. A method for producing a composition comprising alumina, the alumina being surface-modified with a perovskite compound of formula (I), Formula (I) is A ｘ－ｙ A' ｙ B １－ｚ B' ｚ O ３ (In the formula, A is an ion of a metal selected from the group consisting of Li, Na, K, Cs, Mg, Sr, Ba, Ca, Y, La, Ce, Pr, Nd, and Gd; A' is an ion of a metal selected from the group consisting of Li, Na, K, Cs, Mg, Sr, Ba, Ca, Y, La, Ce, Pr, Nd, and Gd; B is an ion of a metal selected from the group consisting of Cu, Mn, Mo, Co, Fe, Ni, Cr, Ti, Zr, Al, Ga, Sc, Nb, V, W, Bi, Zn, Sn, Pt, Rh, Pd, Ru, Au, Ag, and Ir; B' is an ion of a metal selected from the group consisting of Cu, Mn, Mo, Co, Fe, Ni, Cr, Ti, Zr, Al, Ga, Sc, Nb, V, W, Bi, Zn, Sn, Pt, Rh, Pd, Ru, Au, Ag, and Ir; x is 0.7 to 1; y is 0 to 0.5; z is 0 to 0.5, and the method comprises: providing a solution comprising one or more salts of A, one or more salts of B, and optionally one or more salts of A' and / or one or more salts of B'; contacting the solution with alumina to form a slurry; spray drying the slurry to form a spray-dried powder; and heating the spray-dried powder.

11. 1. A method for producing a composition comprising alumina, the alumina being surface-modified with a perovskite compound of formula (I), Formula (I) is A ｘ－ｙ A' ｙ B １－ｚ B' ｚ O ３ (In the formula, A is an ion of a metal selected from the group consisting of Li, Na, K, Cs, Mg, Sr, Ba, Ca, Y, La, Ce, Pr, Nd, and Gd; A' is an ion of a metal selected from the group consisting of Li, Na, K, Cs, Mg, Sr, Ba, Ca, Y, La, Ce, Pr, Nd, and Gd; B is an ion of a metal selected from the group consisting of Cu, Mn, Mo, Co, Fe, Ni, Cr, Ti, Zr, Al, Ga, Sc, Nb, V, W, Bi, Zn, Sn, Pt, Rh, Pd, Ru, Au, Ag, and Ir; B' is an ion of a metal selected from the group consisting of Cu, Mn, Mo, Co, Fe, Ni, Cr, Ti, Zr, Al, Ga, Sc, Nb, V, W, Bi, Zn, Sn, Pt, Rh, Pd, Ru, Au, Ag, and Ir; x is 0.7 to 1; y is 0 to 0.5; z is 0 to 0.5, and the method comprises: providing an aqueous solution comprising one or more salts of A, one or more salts of B, and optionally one or more salts of A' and / or one or more salts of B'; contacting the solution with alumina to form a slurry; contacting the slurry with a base; recovering a solid residue from the slurry; and heating the solid residue.

12. A catalytic article comprising a substrate, the substrate having the composition of claim 1 or 2 disposed thereon.

13. The catalytic article of claim 12, wherein the catalytic article comprises a three-way catalyst (TWC), preferably the catalytic article is a TWC.

14. The catalytic article of claim 12 wherein a platinum group metal (PGM) is supported on the composition.

15. 15. The catalytic article of claim 14, wherein the PGM comprises Pt, Pd, Rh, or a mixture or alloy thereof.

16. 1 g / in ３ ~3g / in ３ 13. The catalyst article of claim 12 having a washcoat loading of

17. The catalytic article of claim 12 , wherein the substrate comprises a wall-flow filter substrate or a flow-through substrate.

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