Improved cerium zirconium complex oxide composition

Abstract

The present invention discloses composite oxide compositions containing a composite oxide of cerium and zirconium and a mixture of iron and strontium. These compositions may optionally further contain additional rare earth dopants. These composite oxide compositions exhibit surprisingly improved low-temperature oxygen storage capacity (OSC) even after aging at high temperatures. Importantly, these composite oxide compositions contain iron and strontium (as oxides), and this mixture of iron and strontium surprisingly provides the composite oxide compositions with improved OSC even after aging at high temperatures, particularly improved OSC at lower temperatures. The compositions can be used as catalyst carriers that can be used in exhaust gas purification catalysts.

Description

Technology Field

[0001] Cross-reference of related applications

[0002] This application is filed as a PCT international application on January 22, 2025, and claims priority and benefit to U.S. provisional application No. 63 / 623,469 filed on January 22, 2024 and U.S. provisional application No. 63 / 626,197 filed on January 29, 2024, the full disclosures of which are incorporated herein by reference in their entirety.

[0003] Technology field

[0004] The present disclosure relates to a composite oxide composition containing oxides of cerium and zirconium and a mixture of iron and strontium. These compositions may optionally further contain additional rare earth dopants. These composite oxide compositions exhibit surprisingly enhanced low-temperature oxygen storage capacity (OSC) even after aging at high temperatures. Background Technology

[0005] Catalytic materials containing ceria zirconia mixed oxide primarily consist of nitrogen oxides (NO₂, mainly NO and NO₂). xIt has utility in numerous fields, including the reduction of unburned hydrocarbons (referred to as), hydrocarbons (HC) such as carbon monoxide (CO), methane (CH4), and non-methane hydrocarbons (NMHC), and other pollutants from gasoline, compressed natural gas (CNG), and diesel fuel internal combustion engines in road vehicles, passenger cars, buses, and trucks, as well as other off-road gasoline, CNG, and diesel engines used in utility vehicles, recreational vehicles, and stationary source power generation. Emission standards for unburned hydrocarbons, carbon monoxide, and nitrogen oxide pollutants are established by various government agencies around the world and must be met, with severe penalties imposed if they are not. To meet these standards, catalytic converters are typically installed in the exhaust lines of these emission sources. Exhaust gases flow through the catalytic converter, and harmful HC and CO are converted into CO2 and H2O. x It is preferentially converted into N2 and O2, and the unconverted CO, HC, and NO x It is emitted into the atmosphere as a primary pollutant from the exhaust pipe. The catalytic converter contains a mixture of non-precious metal oxides and platinum group metals (PGMs).

[0006] Three-way conversion (TWC) catalysts include one or more of these precious metals / platinum group metals (PGMs) combined with a high specific surface area non-precious metal oxide / complex oxide support material. The oxide support material may contain aluminum, titanium, silicon, zirconium, cerium, and mixtures thereof. The ability of the oxide support material to store and release oxygen helps to control catalytic activity. The problem to be solved

[0007] There is a continuing demand for effective composite oxide supports for these platinum group metal catalysts to more efficiently convert emissions into less harmful gases. Furthermore, the development of these composite oxide support materials has so far focused primarily on materials suitable for catalytic converters operating at high temperatures, which are typical for internal combustion engines. As hybrid internal combustion engine / electric vehicles become more common, it is becoming increasingly important to develop catalyst materials with improved oxygen storage capacity (OSC) characteristics at low temperatures to cope with increased on / off cycling and improve the conversion of cold-start hydrocarbons while maintaining industry-standard high-temperature stability, performance, and emission control. means of solving the problem

[0008] The present invention discloses a composition comprising ceria zirconia having mixed oxides. The composition may be used as a catalytic carrier that can be used in an exhaust gas purification catalyst. In particular, the ceria zirconia composition comprises strontium oxide SrO and iron(III) oxide Fe2O3.

[0009] In addition, the present invention discloses washcoat suspension compositions for use as components of a catalytic coating and the preparation of said washcoat compositions. The washcoat is applied to a substrate as a catalytic coating. Such substrates may consist of cordierite, fecralloy metal foil, or foamed ceramic materials.

[0010] The present invention discloses a composite oxide composition comprising a) about 1 to about 45 weight% of cerium based on oxide; b) about 40 to about 98 weight% of zirconium based on oxide; c) about 0.050 weight% to about 0.50 weight% of iron based on oxide; d) about 0.015 weight% to about 0.20 weight% of strontium based on oxide; and e) optionally, an additional rare earth dopant selected from the group consisting of lanthanum, neodymium, yttrium, praseodymium, samarium, gadolinium, and mixtures thereof, wherein, where present, each optional additional rare earth dopant is present in an amount of about 0.5 to about 15 weight% based on oxide. In certain embodiments, the additional rare earth dopant is selected from the group consisting of lanthanum, yttrium, and mixtures thereof and is present in an amount of about 5 to about 15 weight percent based on the oxide. In certain embodiments, the amounts of the individual components will be varied so that the total amount is about 100% of the composite oxide composition.

[0011] Despite the small amounts of iron and strontium, these small amounts impart surprisingly improved properties to the disclosed composite oxide composition. The mixture of iron and strontium surprisingly provides the composite oxide composition with improved OSC even after aging at high temperatures, particularly improved OSC at lower temperatures. The composite oxide composition does not exhibit a perovskite phase or pyrochlore phase detectable by XRD measurement even after aging in air at 1100°C for 10 hours, and the small amounts of iron and strontium may change accordingly.

[0012] In one embodiment, the composite oxide composition comprises a) about 30 to about 45 weight% of cerium based on oxide; b) about 40 to about 65 weight% of zirconium based on oxide; c) about 0.05 to about 0.50 weight% of iron based on oxide; d) about 0.015 to about 0.20 weight% of strontium based on oxide; and e) additional rare earth dopant selected from the group consisting of lanthanum, yttrium and mixtures thereof and present in an amount of about 5 to about 15 weight% based on oxide.

[0013] In addition, a catalyst or catalyst composition comprising the above-mentioned complex oxide composition as an initial feedstock is disclosed.

[0014] In addition, (i) a platinum group metal (PGM) selected from the group consisting of platinum, palladium, rhodium, iridium, osmium, ruthenium and mixtures thereof, and (ii) a) about 1 to about 45 weight% of cerium based on oxide; b) about 40 to about 98 weight% of zirconium based on oxide; c) about 0.05 weight% to about 0.50 weight% of iron based on oxide; d) about 0.015 weight% to about 0.20 weight% of strontium based on oxide; and e) optionally, a suspension comprising a composite oxide composition comprising an additional rare earth dopant selected from the group consisting of lanthanum, neodymium, yttrium, praseodymium, samarium, gadolinium, and mixtures thereof, wherein, if present, each optional additional rare earth dopant is present in an amount of about 0.5 to about 15 weight percent based on the oxide.

[0015] In certain embodiments, the suspension contains rhodium or palladium as a platinum group metal (PGM). In more specific embodiments, the suspension comprises about 55 weight% to about 65 weight% of the composite oxide composition. Effects of the invention

[0016] When a suspension as disclosed herein is dried and calcine, the dried and calcine-dried suspension exhibits improved oxygen storage capacity (OSC), particularly improved OSC at lower temperatures. Brief explanation of the drawing

[0017] Figure 1 is a graph of OSC (μmol / g) at a temperature of 300 to 600°C for the compositions of Examples 1 to 4, 5A, 5B and 7 after aging in air at 1100°C / 10 hours. Figure 2 is a graph of OSC (μmol / g) at a temperature of 350 to 600°C for the compositions of Examples 1 to 3 after aging in air at 1150°C / 6 hours. Figure 3 is a graph of OSC (μmol / g) at temperatures of 350 to 600°C for the compositions of Examples 1, 4 and 6 after aging in air at 1100°C / 10 hours. Figure 4 is a graph of BJH pore size data of the compositions of Examples 1, 4, and 6. Figure 5 is a graph of OSC (μmol / g) at a temperature of 200 to 450°C for the compositions of Examples 10 to 12 (washcoat alone) after aging in air at 1100°C / 10 hours. Figure 6 is a graph of OSC (μmol / g) at a temperature of 200 to 450°C for the compositions of Examples 10 to 12 (complex oxide composition + 1.5 wt% Pd) after aging in air at 1100°C / 10 hours. Figure 7 is a graph of OSC (μmol / g) at a temperature of 200 to 450°C for the compositions of Examples 10 to 12 (complex oxide composition + 0.5 wt% Rh) after aging in air at 1100°C / 10 hours. FIG. 8 is a graph of OSC (μmol / g) at a temperature of 200 to 450°C for the compositions of Examples 13 to 15 (complex oxide composition + 0.23 wt% Rh) after aging in air at 1100°C / 10 hours. Figure 9 is a transmission electron microscope (TEM) image of the composition of Example 2 aged in air at 1100°C for 10 hours. Figure 10 is an X-ray powder diffraction (XRD) of the composition of Example 2 aged in air at 1100°C / 10 hours compared with a tetragonal ceria zirconia composite oxide standard. Figure 11 is an energy-dispersive X-ray spectroscopy (EDS) image of the composition of Example 2 aged in air at 1100°C for 10 hours. Figure 12 is a transmission electron microscope (TEM) image of the composition of Example 5A aged in air at 1100°C for 10 hours. FIG. 13A is an X-ray powder diffraction (XRD) of the composition of Example 5A aged in air at 1100°C for 10 hours compared with a tetragonal ceria zirconia composite oxide standard and a perovskite LaFeO3 (orthorhombic) standard. FIG. 13B is an X-ray powder diffraction (XRD) of the composition of Example 5B aged in air at 1100°C for 10 hours compared with a tetragonal ceria zirconia composite oxide standard and a perovskite LaFeO3 (orthorhombic) standard. Figure 14 is an energy-dispersive X-ray spectroscopy (EDS) image of the composition of Example 5A aged in air at 1100°C for 10 hours. FIG. 15A is a graph of the H2-TPR results of the slurries of Examples 1, 2, 4 and 6 as-prepared, that is, in a "fresh" state. FIG. 15B is a graph of the H2-TPR results of the slurries of Examples 1, 2, 4 and 6 after aging in air at 1100°C for 4 hours. FIG. 16 is a graph of OSC (μmol / g) at a temperature of 350 to 600°C for the compositions of Examples 1, 2, 4 and 6 after aging in air at 1100°C / 10 hours. FIG. 17 is an X-ray powder diffraction (XRD) of the compositions of Examples 1, 2, 4 and 6 aged in air at 1000°C / 10 hours (rich / lean aging) compared with a tetragonal ceria zirconia composite oxide standard and a perovskite LaFeO3 (orthorhombic) standard. Specific details for implementing the invention

[0018] The present disclosure generally relates to composite oxide compositions comprising cerium, zirconium, iron, strontium, and optionally additional rare earth dopants. The present disclosure also relates to suspensions comprising platinum group metals (PGMs) and the composite oxide compositions described herein, as well as supported catalysts prepared from the described composite oxides. The described composite oxides are useful for treating exhaust gases from internal combustion engines and exhibit surprisingly improved low-temperature oxygen storage capacity (OSC) even after aging at high temperatures.

[0019] Before disclosing and describing the composition, catalyst, and method in detail, it should be understood that the present disclosure is not limited to the specific structures, process steps, or materials disclosed herein, but extends to equivalents recognizable by a person skilled in the art. It should also be understood that the terms used herein are used solely for the purpose of describing specific embodiments and are not intended to be limiting. It should be noted that, as used herein, the singular forms “a,” “an,” and “the” include multiple references unless the context clearly indicates otherwise. Accordingly, for example, a reference to “additional rare earth dopants” should not be interpreted as limiting in quantity or source, a reference to “steps” may include multiple steps, a reference to “products” or “products” of a reaction or treatment should not be interpreted as all products of the reaction / treatment, and a reference to “treatment” may include one or more such treatment steps.

[0020] Figures to which "approximately" or "roughly" is attached include typical experimental error. As used herein, the terms "approximately" and "roughly" are used interchangeably and refer to a statistically significant range of values ​​such as specified weight percentages, surface areas, concentration ranges, time ranges, temperatures, pH, etc. Such a range may be within 10%, more typically within 5%, of the indicated value or range. At times, such a range may be within typical experimental error of the standard method used to measure and / or determine the given value or range. The acceptable variation included in the term "approximately" will vary depending on the specific system under study and will be readily understood by a person skilled in the art. Whenever a range is described in this application, at least all integers within that range are also considered as embodiments of the invention.

[0021] The present disclosure relates to a composite oxide composition having improved oxygen storage capacity (OSC) even after aging at high temperatures. These composite oxide compositions are composite oxides of cerium, zirconium, iron, and strontium. The composite oxide compositions are in powder form. The individual components within the composite oxide compositions are closely mixed.

[0022] As disclosed herein, these composite oxide compositions contain, importantly, iron and strontium (as oxides), and such mixture of iron and strontium surprisingly provides the composite oxide compositions with improved OSC even after aging at high temperatures, particularly improved OSC at lower temperatures.

[0023] In certain embodiments, the composite oxide composition also contains a certain amount of additional rare earth dopant. This additional rare earth dopant may be selected from any rare earth or a mixture thereof. In certain embodiments, the additional rare earth dopant is selected from the group consisting of lanthanum, neodymium, yttrium, praseodymium, samarium, gadolinium, and mixtures thereof. In certain embodiments, the additional rare earth dopant is lanthanum, yttrium, or a mixture thereof.

[0024] The above-described complex oxide composition is described as a mixture of oxides of cerium, zirconium, iron, strontium, and optionally one or more additional rare earth dopants, and the amounts of these individual components are measured (and reported) as oxides. However, it is not excluded that any of these components may be present at least partially in the form of hydroxides, oxyhydroxides, carbonates, and / or oxycarbonates. The compositional ratios of these components are determined by a plasma torch analysis technique using optical emission spectroscopy, as described in more detail in the Examples section. This technique measures and reports the components as a weight percentage of equivalent oxides relative to the total weight of the complex oxide composition. This technique provides an accurate elemental analysis of small but significant amounts of iron and strontium present in the disclosed complex oxide composition as described herein.

[0025] The composite oxide compositions disclosed herein comprise about 1 to about 45 weight% of cerium based on oxide; about 40 to about 98 weight% of zirconium based on oxide; about 0.065 weight% to about 0.75 weight% of iron based on oxide; about 0.015 weight% to about 0.25 weight% of strontium based on oxide; and optionally additional rare earth dopants. In certain embodiments, the composite oxide compositions disclosed herein comprise about 1 to about 45 weight% of cerium based on oxide; about 40 to about 98 weight% of zirconium based on oxide; about 0.05 weight% to about 0.50 weight% of iron based on oxide; about 0.015 weight% to about 0.20 weight% of strontium based on oxide; and optionally additional rare earth dopants. Where present, each additional rare earth dopant may be present in an amount of about 0.5 to about 15 weight percent based on the oxide. In certain embodiments, said additional rare earth dopant is selected from the group consisting of lanthanum, neodymium, yttrium, praseodymium, samarium, gadolinium, and mixtures thereof. In specific embodiments, the amounts of the individual components will vary so that the total amount is about 100% of the composite oxide composition. It is important that the composite oxide composition as disclosed herein contains a mixture of strontium and iron in the amounts described.

[0026] Despite the small amounts of iron and strontium, these small amounts impart surprisingly improved properties to the disclosed composite oxide composition. The mixture of iron and strontium surprisingly provides the composite oxide composition with improved OSC even after aging at high temperatures, particularly improved OSC at lower temperatures. These improved properties are provided when both strontium and iron are present and in the amounts described. If there is too much iron, it leads to the formation of a perovskite phase during aging at high temperatures, which acts as a sintering aid, causing the composite oxide composition containing a larger amount of iron to sinter. After sintering, a loss of BET specific surface area occurs, which begins to have a negative effect on the OSC, resulting in a non-linear OSC response compared to the disclosed composite oxide composition containing the mixture of SrO and Fe2O3 within the scope of this disclosure. The amounts of iron and strontium can be adjusted within the ranges disclosed herein to achieve desired properties and prevent the formation of the perovskite phase.

[0027] The above-mentioned complex oxide composition comprises the aforementioned components in the indicated amounts, but in certain embodiments, it may also include other elements and / or small amounts of impurities. In other embodiments, the above-mentioned complex oxide composition essentially consists of the aforementioned components, and the amounts of the individual components will vary so that the total amount is about 100% of the complex oxide composition.

[0028] The additional rare earth dopant may be selected from the group consisting of yttrium (Y), lanthanum (La), neodymium (Nd), praseodymium (Pr), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), and mixtures thereof. In certain embodiments, the additional rare earth dopant is lanthanum, neodymium, yttrium, praseodymium, samarium, gadolinium, or a mixture thereof. In certain embodiments, the additional rare earth dopant is lanthanum, yttrium, or a mixture thereof. Where present, each additional rare earth dopant may be present in an amount of about 0.5 to about 15 weight percent based on oxides. In a specific embodiment, the composite oxide composition contains an additional rare earth dopant in an amount of about 5 to about 15 weight percent based on the oxide. In another embodiment, the composite oxide composition contains about 0 (zero) of the additional rare earth dopant.

[0029] The above composite oxide composition may contain trace amounts of impurities. These impurities are typically present in an amount of about 1 weight percent or less (to about 0 or undetectable amounts) based on the total weight of the composite oxide composition. These impurities include residual solvents, salts, other metals, etc. These other metals include those commonly found in water, such as magnesium, iron, calcium, silicon, sodium, etc. The amount of these impurities (from about 1 weight percent to about 0 or undetectable amounts) may be present in any of the described embodiments of the composite oxide composition. Where present and detectable, any impurity may be present in an amount of about 100 ppm or less.

[0030] In one embodiment, the composite oxide composition as disclosed herein comprises a) about 30 to about 45 weight percent of cerium based on oxide; b) about 40 to about 65 weight percent of zirconium based on oxide; c) about 0.065 to about 0.75 weight percent of iron based on oxide; d) about 0.015 to about 0.25 weight percent of strontium based on oxide; and e) additional rare earth dopant selected from the group consisting of lanthanum, yttrium and mixtures thereof and present in an amount of about 5 to about 15 weight percent based on oxide. In certain of these embodiments, the amounts of the individual components will vary so that the total amount is about 100% of the composite oxide composition.

[0031] In another embodiment, the composite oxide composition comprises a) about 30 to about 45 weight percent of cerium based on oxide; b) about 40 to about 65 weight percent of zirconium based on oxide; c) about 0.05 to about 0.50 weight percent of iron based on oxide; d) about 0.015 to about 0.20 weight percent of strontium based on oxide; and e) optionally, an additional rare earth dopant selected from the group consisting of lanthanum, yttrium and mixtures thereof and present in an amount of about 5 to about 15 weight percent based on oxide. In certain of these embodiments, the amounts of the individual components will be varied so that the total amount is about 100% of the composite oxide composition.

[0032] In specific embodiments, the composite oxide composition as disclosed herein comprises a) about 30 to about 45 weight percent of cerium based on oxide; b) about 40 to about 65 weight percent of zirconium based on oxide; c) about 0.05 to about 0.50 weight percent of iron based on oxide; d) about 0.015 to about 0.20 weight percent of strontium based on oxide; and e) additional rare earth dopant selected from the group consisting of lanthanum, yttrium and mixtures thereof and present in an amount of about 5 to about 15 weight percent based on oxide. In certain embodiments among these, the amounts of the individual components will be varied so that the total amount is about 100% of the composite oxide composition.

[0033] In another embodiment, the composite oxide composition as disclosed herein comprises about 30 to about 45 weight% of cerium based on oxide, about 40 to about 65 weight% of zirconium based on oxide, about 0.1 to about 0.75 weight% of iron based on oxide, about 0.05 to about 0.25 weight% of strontium based on oxide, and optionally additional rare earth dopants, each optional additional rare earth dopant being present in an amount of about 0.5 to about 15 weight% based on oxide. In certain embodiments, where present, the total additional rare earth dopants are present in an amount of about 5 to about 15 weight% based on oxide.

[0034] In another specific embodiment, the composite oxide composition as disclosed herein comprises about 30 to about 45 weight% of cerium based on oxide, about 40 to about 65 weight% of zirconium based on oxide, about 0.1 to about 0.50 weight% of iron based on oxide, about 0.05 to about 0.20 weight% of strontium based on oxide, and optionally additional rare earth dopants, which, if present, are in an amount of about 5 to about 15 weight% based on oxide.

[0035] In certain embodiments of these, the additional rare earth dopant is lanthanum, neodymium, yttrium, praseodymium, samarium, gadolinium, or a mixture thereof. In certain embodiments of these, the additional rare earth dopant is lanthanum, yttrium, or a mixture thereof. In certain embodiments of these, the composite oxide composition contains the additional rare earth dopant in an amount of about 5 to about 15 weight percent based on the oxide. And in other embodiments of these, the composite oxide composition contains about 0 (zero) of the additional rare earth dopant. In specific embodiments, the amounts of the individual components will vary so that the total amount is about 100% of the composite oxide composition.

[0036] In a more specific embodiment, the composite oxide composition of the present disclosure essentially consists of CeO2, ZrO2, La2O3, Y2O3, Fe2O3, and SrO. In a specific embodiment among these embodiments, the composite oxide of the present disclosure essentially consists of CeO2, ZrO2, La2O3, Y2O3, Fe2O3, and SrO, wherein the ratio of Ce / Zr / La / Y / Sr / Fe is approximately 35 wt% to approximately 45 wt% cerium, approximately 45 wt% to approximately 55 wt% zirconium, approximately 3 wt% to approximately 6 wt% lanthanum, approximately 3 wt% to approximately 6 wt% yttrium, approximately 0.03 wt% to approximately 0.2 wt% strontium, and approximately 0.1 wt% to approximately 0.5 wt% iron, based on the oxide. In certain embodiments among these embodiments, the composite oxide composition contains approximately 0.1 weight% to approximately 0.4 weight% of iron based on the oxide.

[0037] As described herein, the composite oxide composition containing both iron and strontium has an improved OSC, particularly a surprisingly improved low-temperature oxygen storage capacity (OSC), even after aging at high temperatures. This improved or enhanced OSC is compared with a composite oxide composition containing the same components (i.e., cerium, zirconium, and any optional rare earth dopant) in roughly the same proportions, except that it does not contain strontium and iron, with the amount of zirconium varied to compensate for the absence of strontium and iron. The OSC is measured as described in the Examples.

[0038] After aging in air at 1100°C for 10 hours, the composite oxide composition as disclosed herein may exhibit an oxygen storage capacity (OSC) that is 2 to 8 times higher than that of the same composition that does not contain a mixture of iron and strontium at about 200°C to about 600°C. In a specific embodiment, after aging in air at 1100°C for 10 hours, the composite oxide composition exhibits an oxygen storage capacity (OSC) that is 2 to 8 times higher than that of the same composition that does not contain a mixture of iron and strontium at about 250°C to about 600°C. In a specific embodiment, after aging in air at 1100°C for 10 hours, the composite oxide composition exhibits an oxygen storage capacity (OSC) that is 2 to 7 times higher than that of the same composition that does not contain a mixture of iron and strontium at about 250°C to about 600°C.

[0039] As defined above, "the same composition not containing a mixture of iron and strontium" means a composite oxide composition containing the same components (i.e., cerium, zirconium, and any optional rare earth dopant) in roughly the same proportions, except that it does not contain strontium and iron, with the amount of zirconium changed to compensate for the absence of strontium and iron.

[0040] In a specific embodiment, after aging in air at 1100°C for 10 hours, the composite oxide composition as disclosed herein may exhibit an oxygen storage capacity (OSC) two to four times higher than that of the same composition not containing a mixture of iron and strontium at about 250°C to about 600°C. As described, this improved OSC is particularly enhanced at low temperatures. Thus, these improvements may be particularly pronounced at temperatures of about 200°C to about 450°C or about 250°C to about 450°C.

[0041] In a specific embodiment, after aging in air at 1150°C for 6 hours, the composite oxide composition may exhibit an oxygen storage capacity (OSC) two to three times higher than that of the same composition not containing a mixture of iron and strontium at about 250°C to about 600°C. These improvements may be particularly pronounced at temperatures of about 200°C to about 450°C or about 250°C to about 450°C.

[0042] Any of these improved OSC characteristics may be combined with each other and may be combined with any embodiment of the composite oxide composition described above and / or any characteristic described below.

[0043] The above composite oxide composition may also exhibit other advantageous physical properties both in the manufactured state and after aging at high temperatures.

[0044] As described above, the composite oxide composition advantageously contains small amounts of iron and strontium, and importantly, prevents the formation of a perovskite phase after aging at high temperatures. Accordingly, in certain embodiments, the composite oxide composition does not exhibit a perovskite phase or a pyrochlore phase detectable by XRD measurement after aging in air at 1100°C for 10 hours. Small amounts of iron and strontium may be modified so as not to form a perovskite phase after aging at high temperatures. The composite oxide composition may exhibit a tetragonal or cubic phase when measured by XRD after aging in air at 1100°C for 10 hours.

[0045] In a specific embodiment, the composite oxide composition exhibits a tetragonal or cubic phase when measured by XRD after aging in air at 1150°C for 6 hours. The composite oxide composition may not exhibit a detectable perovskite or pyrochlore phase when measured by XRD after aging in air at 1150°C for 6 hours.

[0046] In a specific embodiment, after aging in air at 1100°C for 10 hours, the composite oxide composition as disclosed herein may have a crystallite size of about 50 nm to about 100 nm. Any of these crystalline phase embodiments may be combined and may be combined with any embodiment of the composite oxide composition described above and / or any characteristic described below.

[0047] As described herein, the formation of detectable perovskite phases is undesirable. If there is too much iron (more iron than in the composite oxide compositions currently disclosed), it leads to the formation of perovskite phases during aging at high temperatures, which acts as a sintering aid and causes the composite oxide composition to sinter. After sintering, a loss of BET specific surface area occurs, which begins to have a negative effect on OSC. The loss of OSC is undesirable and is prevented by the composite oxide compositions disclosed herein.

[0048] The above composite oxide composition may also exhibit a favorable BET specific surface area. The BET specific surface area is measured as described in the Examples. In certain embodiments, the above composite oxide composition as disclosed herein has a surface area of ​​about 40 to about 80 m² 2 Exhibiting a fresh BET specific surface area of ​​ / g, and in certain embodiments, these composite oxide compositions have about 40 to about 50 m² 2 It represents a fresh BET specific surface area of ​​ / g. As described herein, "fresh" means "as prepared" and is a state without additional aging at high temperatures. In certain embodiments, the composite oxide composition has approximately 10 m² when aged in air at 1100°C for 10 hours. 2 / g to about 20 m 2It exhibits a BET specific surface area of ​​ / g. In a specific embodiment, the composite oxide composition has a surface area of ​​approximately 2 m² when aged in air at 1150°C for 6 hours. 2 / g greater than or about 10 m 2 It exhibits a BET specific surface area of ​​less than / g. Despite the lower BET specific surface area after aging in air at 1150°C for 6 hours, OSC remains 2 to 3 times higher than the same composition lacking SrO and Fe2O3.

[0049] Any of these BET specific surface area embodiments may be combined and may be combined with any embodiment of the composite oxide composition described above.

[0050] The above composite oxide composition may also exhibit a favorable particle size. The particle size is measured as described in the Examples. In certain embodiments, the composite oxide composition has a D of about 6 μm to about 20 μm. 90 and D of about 1 μm to about 10 μm 10 It has a particle size characterized by

[0051] After 4 hours at approximately 1100°C in air, the composite oxide composition may have a Hydrogen Temperature Programmed Reduction (H2TPR) exhibiting a single symmetric reduction peak when aged at approximately 1100°C in air for 4 hours. The H2TPR is measured as described in the examples. As the mixture of iron oxide (Fe2O3) and strontium oxide (SrO) increases within the amounts disclosed herein, the peak reduction temperature decreases, which correlates with increased low-temperature OSC performance (see FIG. 8). Note that a lower peak reduction temperature corresponds to a lower OSC light-off temperature, which correlates with improved OSC at lower temperatures.

[0052] Pore ​​size is an important physical property of the complex oxide composition. Pore size is measured as described in the examples. Pores enable the diffusion of low molecular weight and high molecular weight macromolecular gaseous reactants. The complex oxide composition may exhibit a favorable pore size in its prepared state (after initial heat treatment / calcination associated with the manufacturing process). In some embodiments, primary, secondary, tertiary, and quaternary ammonium hydroxides are used as precipitating agents during the preparation of the complex oxide composition to increase the pore size. As shown in FIG. 4, the use of tetramethyl ammonium hydroxide (TMAOH) may affect the pore size of the complex oxide composition. Ammonium hydroxides may be used to increase the pore size without negatively affecting other physical properties of the complex oxide composition. Optimizing pore size is important because the pore size must be sufficient for the diffusion of harmful gases, but it must not be too large since it increases with high-temperature aging.

[0053] Any embodiment of the complex oxide composition described above may be used as an initial feedstock in a catalyst or catalyst composition.

[0054] Preparation of a complex oxide composition

[0055] The above-described composite oxide composition as disclosed herein is prepared by a method as described in the attached examples.

[0056] For example, in the first step, a zirconium salt such as zirconium basic carbonate, a cerium compound (e.g., cerium hydroxide) or a salt of cerium (e.g., cerium carbonate), and any optional additional rare earth dopant salt (e.g., yttrium carbonate) are dissolved in a mixture of deionized water and nitric acid. Alternatively, soluble salts such as nitrates or chlorides may be used and dissolved directly in deionized water. Subsequently, a mixed rare earth zirconium nitrate solution is precipitated in a mixture of deionized water, ammonium hydroxide, and lauric acid. The pH of this step is controlled to approximately 9 to approximately 11.

[0057] In the second step, any additional rare earth dopant salt (e.g., lanthanum carbonate) is dissolved in nitric acid and deionized water together with iron nitrate and strontium nitrate. This mixture is added to the precipitate from the first step while controlling the pH to approximately 9 to 11. The mixture is continuously mixed. A precipitate is formed, which is then filtered and washed.

[0058] The separated precipitate is calcined / heat-treated at a temperature of about 750°C to about 1000°C for about 4 hours to about 8 hours. In certain embodiments, the separated precipitate is calcined / heat-treated at about 850°C to about 1050°C or at about 950±50°C. The calcined material can be milled to a specific particle size if desired.

[0059] Further details regarding the preparation of the composite oxide composition are described in Examples 1 to 7 below.

[0060] Wash coat ( washcoat ) Composition and preparation thereof

[0061] In addition, the present invention discloses washcoat suspension compositions for use as components of a catalyst coating and the preparation of said washcoat compositions. The washcoat is applied to a catalyst support as a catalyst coating. A washcoat as disclosed herein is applied from a suspension to a substrate and then dried and heat-treated / calcined. The suspension may also be described as a slurry, and these two terms are used interchangeably. After being applied to the support, the suspension is dried and calcined to produce a dried and calcined washcoat powder. This dried and calcined catalyst washcoat powder and the composite support (or substrate) may be referred to as a coated catalyst article, which becomes a catalytic converter when assembled or canned in a metal case. This dried and calcined washcoat powder has an improved OSC even after aging at high temperatures, particularly an improved OSC at lower temperatures.

[0062] As disclosed herein, the washcoat suspension comprises (i) a platinum group metal (PGM) selected from the group consisting of platinum, palladium, rhodium, iridium, osmium, ruthenium, and mixtures thereof, and (ii) a composite oxide composition as disclosed herein. In some embodiments, the suspension may contain about 55 weight% to about 65 weight% of the composite oxide composition. These composite oxide compositions include all embodiments of the composite oxide compositions described herein. Accordingly, the composite oxide composition may comprise a) about 1 to about 45 weight% of cerium based on oxide; b) about 40 to about 98 weight% of zirconium based on oxide; c) about 0.065 weight% to about 0.75 weight% of iron based on oxide; d) about 0.015 weight% to about 0.25 weight% of strontium based on oxide; and e) optionally additional rare earth dopants. In certain embodiments, the composite oxide composition may comprise a) about 1 to about 45 weight% of cerium based on the oxide; b) about 40 to about 98 weight% of zirconium based on the oxide; c) about 0.05 to about 0.50 weight% of iron based on the oxide; d) about 0.015 to about 0.20 weight% of strontium based on the oxide; and e) optionally an additional rare earth dopant. The additional rare earth dopant may be any rare earth or a mixture thereof. In certain embodiments, the additional rare earth dopant is selected from the group consisting of lanthanum, neodymium, yttrium, praseodymium, samarium, gadolinium, and mixtures thereof. Where present, each optional additional rare earth dopant is present in an amount of about 0.5 to about 15 weight% based on the oxide. In specific embodiments, the amounts of individual components will be varied so that the total amount is about 100% of the complex oxide composition.

[0063] It should be noted that the above washcoat suspension comprises all complex oxide compositions disclosed herein and comprises all characteristics / features disclosed herein with respect to complex oxide compositions.

[0064] In one embodiment, the washcoat suspension comprises (i) a platinum group metal (PGM) selected from the group consisting of platinum, palladium, rhodium and mixtures thereof, and (ii) a) cerium in an amount of about 30 to about 45 weight% based on oxide; b) zirconium in an amount of about 40 to about 65 weight% based on oxide; c) an additional rare earth dopant selected from the group consisting of lanthanum, yttrium and mixtures thereof and present in an amount of about 5 to about 15 weight% based on oxide; and d) a mixture of iron and strontium, wherein the iron is present in an amount of about 0.1 weight% to about 0.75 weight% based on oxide and the strontium is present in an amount of about 0.05 weight% to about 0.25 weight% based on oxide. In specific embodiments among these, the amounts of the individual components will be varied such that the total amount is about 100% of the complex oxide composition.

[0065] In certain embodiments, the washcoat suspension comprises (i) a platinum group metal (PGM) selected from the group consisting of platinum, palladium, rhodium, and mixtures thereof, and (ii) a) cerium in an amount of about 30 to about 45 weight% based on oxide; b) zirconium in an amount of about 40 to about 65 weight% based on oxide; c) additional rare earth dopant selected from the group consisting of lanthanum, yttrium, and mixtures thereof, present in an amount of about 5 to about 15 weight% based on oxide; and d) a mixture of iron and strontium, wherein the iron is present in an amount of about 0.1 weight% to about 0.50 weight% based on oxide and the strontium is present in an amount of about 0.05 weight% to about 0.20 weight% based on oxide. In specific embodiments among these, the amounts of the individual components will be varied such that the total amount is about 100% of the complex oxide composition.

[0066] In certain embodiments, the platinum group metal (PGM) used in the washcoat suspension is rhodium or palladium, and in certain embodiments, the PGM is rhodium. In other embodiments, the PGM used in the washcoat suspension is palladium.

[0067] In an embodiment in which the washcoat suspension composition contains rhodium, the suspension may contain about 0.2 weight% to about 0.50 weight% of rhodium as a metal dispersed based on a complex oxide. In an embodiment in which the washcoat suspension contains palladium, the suspension may contain about 0.5 weight% to about 1.50 weight% of palladium as a metal dispersed based on a complex oxide.

[0068] A washcoat slurry as disclosed herein is prepared by adding the complex oxide composition, aluminum oxide (Al2O3), an insoluble alkaline earth (ALKA) salt, and a pseudoboehmite binder to deionized water. In certain embodiments, the aluminum oxide may be Al2O3 doped with La2O3. The deionized water may also contain a carboxylic acid, and in certain embodiments, the carboxylic acid may be acetic acid. The carboxylic acid in the suspension may be used to adjust the pH of the suspension to about 4 to about 6. In certain embodiments, the deionized water may further contain sucrose. The final slurry has a low nitric acid content.

[0069] The above-mentioned insoluble alkaline earth metal (AE) salt is used as a washcoat stabilizer and a pore-forming agent. In certain embodiments, the insoluble alkaline earth metal is barium sulfate (BaSO4), which is known to minimize solubility / interaction with the complex oxide composition during the preparation of the washcoat slurry composition and to create porosity at high temperatures during use.

[0070] Accordingly, the washcoat slurry as described herein may contain one or more of La2O3-doped Al2O3, BaSO4, a pseudobermite binder, a carboxylic acid (e.g., acetic acid), and / or sucrose. In certain embodiments, the washcoat slurry has a solid content of about 40% by weight to about 50% by weight when dried and calcined at about 1000±50°C.

[0071] In some embodiments, a platinum group metal (PGM) is added after the base slurry is prepared to minimize interaction with the composite oxide composition and to prepare the catalyst washcoat. In some embodiments, the platinum group metal (PGM) is selected from the group consisting of platinum, palladium, rhodium, iridium, osmium, and ruthenium as a single metal and as a mixture thereof, and in certain embodiments among these, it is palladium, rhodium, or a mixture thereof. The platinum group metal (PGM) may be added to the base slurry as a nitrate solution prepared from a nitrate of the platinum group metal (PGM).

[0072] After the washcoat slurry composition is prepared, the slurry composition is dried / calcined at about 500°C to about 600°C for about 45 minutes to about 3 hours.

[0073] The above-described dried and calcined powder has an improved OSC even after aging at high temperatures, particularly a surprisingly improved low-temperature oxygen storage capacity (OSC). These improvements may be particularly pronounced at temperatures of about 250°C to about 450°C. The above-described dried and calcined powder exhibits an improved oxygen storage capacity (OSC) at about 250°C to about 600°C compared to a dried and calcined suspension containing a complex oxide composition having the same composition but not containing a mixture of iron and strontium. In certain embodiments, these improvements may be particularly pronounced when the above-described dried slurry powder contains rhodium as a platinum group metal (PGM).

[0074] The composite oxide compositions and slurry compositions described herein are further characterized and described in the following examples. These examples also provide details on techniques for measuring the physical properties of the composite oxide compositions. However, the above examples do not limit the compositions described herein.

[0075] Further details regarding the preparation of the washcoat suspension are described in Examples 10 to 15 below.

[0076] Examples (Example)

[0077] OSC measurement: OSC measurements were performed under the following conditions. Powder samples were aged / heated under target conditions. Data in Tables 2, 3, 4, and 7 utilized 1100°C / 10 hours in air and 1150°C / 6 hours in air. For OSC measurements, the O2 pulse chemisorption method was used to perform OSC measurements at the desired temperatures. Examples include, but are not limited to, 200°C, 300°C, 350°C, 450°C, and 600°C. For example, for OSC measurements at 350°C, characterization was performed on a Micrometrics Autochem 2920 system, where 0.1 g of the sample was weighed and placed into a quartz sample tube filled with a quartz wool bed. The sample was then pretreated, where the temperature was first set to 50 cm 3 The temperature was raised to 350°C under a He gas flow rate of 1 / min, followed by the application of 10 pulses of 10% O2 / He, and then an additional 20 pulses of 10% CO / He were applied while maintaining the target temperature. After that, pulses of 10% O2 / He were applied until the sample reached saturation, and the oxygen storage capacity was measured as the cumulative amount of O2 absorbed at 350°C.

[0078] Composition content:Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES), manufactured by Agilent and model number Agilent ICP-OES 5110, is used to provide accurate elemental analysis of major components (e.g., Ce, Zr, La, and Y). It operates by introducing a sample into a high-temperature plasma to ionize and excite its atoms. When the excited chemical species return to their ground state, they emit light of a characteristic wavelength, which is dispersed and detected to generate a spectrum. This enables the identification and quantification of elements based on their specific wavelengths. The sample is first dissolved in an acid to release the target element, then atomized in an atomization chamber to form a fine aerosol, which is introduced into a rectangular plasma tube. Consequently, the sample is directly excited by an argon plasma light source for spectroscopic measurement, and the results are normalized. Calibration standards help correlate intensity with concentration. Atomic Absorption Spectroscopy (AAS), manufactured by Agilent and model number Agilent AAS 200 Series AA. Used to provide accurate elemental analysis of Fe and Sr, this technique operates by introducing a sample into a flame and converting it into a fine aerosol. Next, a hollow cathode lamp is used to emit light of a wavelength corresponding to the absorption line of the target element. At a specific wavelength, atoms absorb the emitted light, and the amount of absorbed light is measured by a detector. The sample is first dissolved in acid to release the target element. Strontium oxide and iron oxide are measured using the standard curve method, respectively, with specific lamps mounted on the atomic absorption spectrometer, and are subsequently ionized in an air-acetylene flame drawn in as a diluted sample / acid medium. The decrease in intensity is proportional to the concentration of the corresponding element in the sample.

[0079] SEM method: Scanning electron microscope (SEM) images were obtained using a JEOL model JSM-6010LV, and the powder sample to be analyzed was attached to a sample stub via carbon tape. The SEM generated images of the sample by raster scanning the surface with a high-energy electron beam. A magnet focuses the electron beam to a single point with a diameter of several nanometers. As electrons interact with atoms within the sample, various signals are generated and aggregated by various imaging and analysis detectors. Generally, secondary electrons emitted from atoms excited by the electron beam are detected by secondary electron detectors to reveal the surface morphology.

[0080] SEM -EDS method: For SEM energy-dispersed x-ray spectroscopy (EDS), the instrument used was an Oxford Instruments model number x-act (10 mm 2 It was a silicon drift detector. Sample preparation was identical to that of the SEM sample, and the powder sample was attached to the sample stub via carbon tape. Energy-dispersive spectroscopy (EDS) utilizes characteristic X-rays emitted from the sample during SEM imaging. These X-rays are emitted when outer shell electrons replace inner shell electrons displaced by the high-energy SEM electron beam. Since each element has a unique energy difference between its outer and inner shells, characteristic X-rays are detected at specific energies and can be associated with elemental identification. The silicon drift detector (SDD) is the most common type of EDS detector used in SEM instruments.

[0081] TEM -EDS method:For the transmission electron microscope (TEM) EDS, the instrument used was a Thermofisher model number Thermofisher Talos F200X TEM (equipped with a Super-X SDD detector). Transmission electron microscopy (TEM) uses an electron beam that passes through a thin specimen to obtain high-resolution images of its internal structure. This is often combined with EDS techniques to analyze X-rays generated when electrons are irradiated onto the specimen and to provide information regarding the elemental composition of the sample. To prepare ultrathin specimens (typically less than 100 nm) for electron transmission, the FIB technique is used to precisely mill and remove materials at the nanoscale using a focused ion beam (typically gallium ions). TEM specimens were prepared by a focused ion beam (FIB, Thermofisher Helios G4 UX) at 30 keV, and the final FIB cleaning of the TEM lamellae was performed at 5 keV to minimize surface amorphization of the thin lamellae.

[0082] XRD method: For X-ray diffraction (XRD), the following method was used. The instrument used was a multi-purpose X-ray diffractometer, model number Empyrean, manufactured by Malvern Panalytical. Powder samples (1 to 2 g) were prepared by loading the material to be analyzed into a shallow-well sample holder (using a glass slide) and flattening it. X-ray diffraction (XRD) is the result of constructive interference between X-rays and a crystalline sample. The wavelength of the X-rays used is of the same order as the interatomic distance within the crystal lattice. This generates diffraction patterns that can be analyzed in various ways, the most widely used being the application of the famous Bragg law (nλ = 2d sin θ), which is used for measuring crystals and their phases. A scan rate of 0.001395° / sec and a step size of 0.0393908° were used.

[0083] N 2 BET SA using and BJH Pore ​​Size / Radius and Pore Volume Method: This method was used to obtain BET (Brunauer, Emmett and Teller) Specific Surface Area (SA) and BJH (Barrett, Joyner, and Halenda) Pore Radius (PR) and Pore Volume (PV) data. The instrument used was a Micromeritics Model No. ASAP 2460 Specific Surface Area and Pore Analyzer. To prepare the powder sample for analysis, the sample was first degassed at 350°C for 2 hours. This technique involves exposing the material to N2 gas and measuring the amount of adsorbed N2 gas at different pressures. The BET theory applied to determine the specific surface area of ​​the material relates the amount of adsorbed gas at a given pressure to the coverage of the monolayer of N2 adsorbate on the surface. The BJH theory applied to determine pore volume and pore size distribution analyzes the desorption isotherm across the relative pressure range where desorption occurs.

[0084] H 2 TPR method: The following method was used to obtain H2TPR data. The instrument used was a Micromerics Autochem II 2920 automated catalyst characterization system. All analyzed samples were aged / heated in air at 1100°C for 4 hours. The gas used was 5% H2 in argon, and the temperature program was to heat up to 1000°C (heating rate: 13°C / min). Reduction was repeated for 2 cycles, and the samples were oxidized prior to the second cycle.

[0085] Particle size method:Particle size was measured by laser using a Malvern Mastersizer. Since the particle size distribution does not require wet milling, it reduces mechanical and chemical exposure during the washcoat manufacturing stage. Additionally, dry milling reduces chemical erosion caused by mechanical wet milling at high temperatures.

[0086] catalyst Wash coat Simulation test method: Using a wire winding rod with a 1.0 mm spacing, slurry beads were placed on a smooth soda-lime glass plate. The slurry was rapidly and uniformly drawn down to form a thin film approximately 25 μm (micron) thick. The glass plate was then rapidly placed into a drying oven controlled at 150°C and left for 20 minutes to form a dry film. The film was scraped off with a plastic spoon, collected, and calcined at 550°C for 2 hours. The calcined slurry powder was used for subsequent thermal aging studies (e.g., at 1100°C for 10 hours). This method simulates the rapid drying of the catalyst washcoat slurry. Slurry characteristics, physical properties, and the resulting OSC measurements can be found in Tables 5, 6, and 7, respectively, described in the examples below.

[0087] Complex oxide composition Examples :

[0088] Comparative example (Comparative Example) 1: Seria Zirconia Preparation of a composition

[0089] A 6.0 kg batch of ceria zirconia with a target composition of 40 / 50 / 5 / 5 CeO2 / ZrO2 / La2O3 / Y2O3 was prepared by first dissolving 7.500 kg of ZBC (Zirconium basic carbonate), 3.636 kg of Ce(OH)4 (Cerium IV hydroxide), 0.545 kg of La2(CO3)3 (lanthanum carbonate), and 0.475 kg of Y2(CO3)3 (yttrium carbonate) in a mixture of 28 L of DI H2O (deionized water) and 15 L of 8M HNO3 (nitric acid). Next, the mixed rare earth zirconium nitrate solution was mixed with 63 L of DI H2O (deionized water), 31.5 L of NH4OH (ammonium hydroxide, 25% NH3 aqueous solution), and 3.0 kg of C 12 H 24 It was precipitated with a mixture of O2 (lauric acid). The final pH was controlled to be between 9.5 and 10.0. Continuous mixing was performed throughout the entire process. Subsequently, the final precipitate was filtered, washed, and calcined at 750°C to 1000°C ("calcined" or "calcined" refers to heat treatment during manufacturing), preferably 950±50°C. The material was then milled to a final particle size D90 ≤ 20 μm.

[0090] Additional details are described in the summary of Examples 1 to 7 below.

[0091] Examples (Example) 2: SrO and Fe 2 O 3 second including Seria Zirconia Preparation of composition

[0092] A 6.0 kg batch of ceria zirconia with a target composition of 40 / 49.56 / 5 / 5 / 0.09 / 0.35 CeO2 / ZrO2 / La2O3 / Y2O3 / SrO / Fe2O3 was first prepared by dissolving 7.434 kg of ZBC (zirconium basic carbonate), 3.636 kg of Ce(OH)4 (cerium(IV) hydroxide), and 0.475 kg of Y2(CO3)3 (yttrium carbonate) in a mixture of 28 L of DI H2O (deionized water) and 15 L of 8 M HNO3 (nitric acid). Subsequently, a mixed rare-earth zirconium nitrate solution was prepared by dissolving 63 L of DI H2O (deionized water), 31.5 L of NH4OH (ammonium hydroxide, 25% aqueous NH3 solution), and 3.0 kg of C 12 H 24 It was precipitated with a mixture of O2 (lauric acid). The final pH of the first step was controlled to be between 9.5 and 10.0.

[0093] As a second step, a mixture of 0.545 kg of La2(CO3)3 (lanthanum carbonate), 0.011 kg of Sr(NO3)2 (strontium nitrate), and 0.106 kg of Fe(NO3)3·9H2O (iron(III) nitrate nonahydrate) dissolved in 1.0 L of 8 M HNO3 (nitric acid) and 2.6 L of DI H2O (deionized water) was added to the precipitate from the first step while controlling the final pH to between 9.5 and 10.0. Continuous mixing was performed throughout the entire process. The resulting final precipitate was then filtered, washed, and calcined at 750°C to 1000°C, preferably 950 ± 50°C. Subsequently, the material was milled to a final particle size D90 ≤ 20 μm.

[0094] Additional details are described in the summary of Examples 1 to 7 below.

[0095] Comparative example (Comparative Example) 3: Fe 2 O 3 second Including SrO is Not including Seria Zirconia Preparation of a composition

[0096] A 6.0 kg batch of ceria zirconia with a target composition of 40 / 49.67 / 5 / 5 / 0.33 CeO2 / ZrO2 / La2O3 / Y2O3 / Fe2O3 was first prepared by dissolving 7.451 kg of ZBC (zirconium basic carbonate), 3.636 kg of Ce(OH)4 (cerium(IV) hydroxide), and 0.475 kg of Y2(CO3)3 (yttrium carbonate) in a mixture of 28 L of DI H2O (deionized water) and 15 L of 8 M HNO3 (nitric acid). Subsequently, a mixed rare-earth zirconium nitrate solution was prepared by dissolving 63 L of DI H2O (deionized water), 31.5 L of NH4OH (ammonium hydroxide, 25% aqueous NH3 solution), and 3.0 kg of C 12 H 24 It was precipitated with a mixture of O2 (lauric acid). The final pH of the first step was controlled to be between 9.5 and 10.0.

[0097] As a second step, a mixture of 0.545 kg of La2(CO3)3 (lanthanum carbonate) and 0.100 kg of Fe(NO3)3·9H2O (iron(III) nitrate nonhydrate) dissolved in 1.0 L of 8 M HNO3 (nitric acid) and 2.6 L of DI H2O (deionized water) was added to the precipitate from the first step while controlling the final pH to between 9.5 and 10.0. Continuous mixing was performed throughout the entire process. Subsequently, the final precipitate was filtered, washed, and calcined at 750°C to 1000°C, preferably 950 ± 50°C. The material was then milled to a final particle size D90 ≤ 20 μm.

[0098] Further details are described in the summary of Examples 1 to 7 below.

[0099] Examples (Example) 4: SrO and Fe 2 O3 second including Seria Zirconia Preparation of a composition

[0100] A 6.0 kg batch of ceria zirconia with a target composition of 40 / 49.79 / 5 / 5 / 0.04 / 0.17 CeO2 / ZrO2 / La2O3 / Y2O3 / SrO / Fe2O3 was first prepared by dissolving 7.469 kg of ZBC (zirconium basic carbonate), 3.636 kg of Ce(OH)4 (cerium(IV) hydroxide), and 0.475 kg of Y2(CO3)3 (yttrium carbonate) in a mixture of 28 L of DI H2O (deionized water) and 15 L of 8 M HNO3 (nitric acid). Subsequently, a mixed rare-earth zirconium nitrate solution was prepared by dissolving 63 L of DI H2O (deionized water), 31.5 L of NH4OH (ammonium hydroxide, 25% aqueous NH3 solution), and 3.0 kg of C 12 H 24 It was precipitated with a mixture of O2 (lauric acid). The final pH of the first step was controlled to be between 9.5 and 10.0.

[0101] As a second step, a mixture of 0.545 kg of La2(CO3)3 (lanthanum carbonate), 0.005 kg of Sr(NO3)2 (strontium nitrate), and 0.052 kg of Fe(NO3)3·9H2O (iron(III) nitrate nonhydrate) dissolved in 1.0 L of 8 M HNO3 (nitric acid) and 2.6 L of DI H2O (deionized water) was added to the precipitate from the first step while controlling the final pH to between 9.5 and 10.0. Continuous mixing was performed throughout the entire process. Subsequently, the final precipitate was filtered, washed, and calcined at 750°C to 1000°C, preferably 950 ± 50°C. The material was then milled to a final particle size D90 ≤ 20 μm.

[0102] Further details are described in the summary of Examples 1 to 7 below.

[0103] Comparative example (Comparative Example) 5A: SrO and more Yang Fe 2 O 3 second Ceria containing Zirconia Preparation of a composition

[0104] A 6.0 kg batch of ceria zirconia with a target composition of 40 / 47.82 / 5 / 5 / 0.45 / 1.73 CeO2 / ZrO2 / La2O3 / Y2O3 / SrO / Fe2O3 was first prepared by dissolving 7.173 kg of ZBC (zirconium basic carbonate), 3.636 kg of Ce(OH)4 (cerium(IV) hydroxide), and 0.475 kg of Y2(CO3)3 (yttrium carbonate) in a mixture of 28 L of DI H2O (deionized water) and 15 L of 8 M HNO3 (nitric acid). Subsequently, a mixed rare-earth zirconium nitrate solution was prepared by dissolving 63 L of DI H2O (deionized water), 31.5 L of NH4OH (ammonium hydroxide, 25% aqueous NH3 solution), and 3.0 kg of C 12 H 24 It was precipitated with a mixture of O2 (lauric acid). The final pH of the first step was controlled to be between 9.5 and 10.0.

[0105] As a second step, a mixture of 0.545 kg of La2(CO3)3 (lanthanum carbonate), 0.055 kg of Sr(NO3)2 (strontium nitrate), and 0.525 kg of Fe(NO3)3·9H2O (iron(III) nitrate nonhydrate) dissolved in 1.0 L of 8 M HNO3 (nitric acid) and 2.6 L of DI H2O (deionized water) was added to the precipitate from the first step while controlling the final pH to between 9.5 and 10.0. Continuous mixing was performed throughout the entire process. Subsequently, the final precipitate was filtered, washed, and calcined at 750°C to 1000°C, preferably 950 ± 50°C. The material was then milled to a final particle size D90 ≤ 20 μm.

[0106] Examples (Example) 5B: SrO and more Yang Fe 2 O 3 second including Seria Zirconia Preparation of a composition

[0107] A 6.0 kg batch of ceria zirconia with a target composition of 40 / 49.12 / 5 / 5 / 0.18 / 0.70 CeO2 / ZrO2 / La2O3 / Y2O3 / SrO / Fe2O3 was first prepared by dissolving 7.368 kg of ZBC (zirconium basic carbonate), 3.636 kg of Ce(OH)4 (cerium(IV) hydroxide), and 0.475 kg of Y2(CO3)3 (yttrium carbonate) in a mixture of 28 L of DI H2O (deionized water) and 15 L of 8 M HNO3 (nitric acid). Subsequently, a mixed rare-earth zirconium nitrate solution was prepared by dissolving 63 L of DI H2O (deionized water), 31.5 L of NH4OH (ammonium hydroxide, 25% aqueous NH3 solution), and 3.0 kg of C 12 H 24 It was precipitated with a mixture of O2 (lauric acid). The final pH of the first step was controlled to be between 9.5 and 10.0.

[0108] As a second step, a mixture of 0.545 kg of La2(CO3)3 (lanthanum carbonate), 0.022 kg of Sr(NO3)2 (strontium nitrate), and 0.213 kg of Fe(NO3)3·9H2O (iron(III) nitrate nonhydrate) dissolved in 1.0 L of 8 M HNO3 (nitric acid) and 2.6 L of DI H2O (deionized water) was added to the precipitate from the first step while controlling the final pH to between 9.5 and 10.0. Continuous mixing was performed throughout the entire process. Subsequently, the final precipitate was filtered, washed, and calcined at 750°C to 1000°C, preferably 950 ± 50°C. The material was then milled to a final particle size D90 ≤ 20 μm.

[0109] Further details are described in the summary of Examples 1 to 7 below.

[0110] Examples (Example) 6: SrO and Fe 2 O 3 second including Seria Zirconia Preparation of composition

[0111] A 6.0 kg batch of ceria zirconia with a target composition of 40 / 49.79 / 5 / 5 / 0.04 / 0.17 CeO2 / ZrO2 / La2O3 / Y2O3 / SrO / Fe2O3 was first prepared by dissolving 7.469 kg of ZBC (zirconium basic carbonate), 3.636 kg of Ce(OH)4 (cerium(IV) hydroxide), and 0.475 kg of Y2(CO3)3 (yttrium carbonate) in a mixture of 28 L of DI H2O (deionized water) and 15 L of 8 M HNO3 (nitric acid). The mixture was then heated to 50°C. Next, the mixed rare earth zirconium nitrate solution, 100 L of DI H2O (deionized water) preheated to 50°C, 5.3 kg of TMAOH (tetramethylammonium hydroxide, 97%), and 3.0 kg of C 12 H 24 It was precipitated with a mixture of O2 (lauric acid). The final pH of the first step was controlled to be between 9.5 and 10.0.

[0112] As a second step, a mixture of 0.545 kg of La2(CO3)3 (lanthanum carbonate), 0.005 kg of Sr(NO3)2 (strontium nitrate), and 0.052 kg of Fe(NO3)3·9H2O (iron(III) nitrate nonhydrate) dissolved in 1.0 L of 8 M HNO3 (nitric acid) and 2.6 L of DI H2O (deionized water) was added to the precipitate from the first step while controlling the final pH to between 9.5 and 10.0. Continuous mixing was performed throughout the entire process. Subsequently, the final precipitate was filtered, washed, and calcined at 750°C to 1000°C, preferably 950 ± 50°C. The material was then milled to a final particle size D90 ≤ 20 μm.

[0113] Further details are described in the summary of Examples 1 to 7 below.

[0114] Examples (Example) 7: less Yang SrO and Fe 2 O 3 second including Seria Zirconia Preparation of a composition

[0115] A 6.0 kg batch of ceria zirconia with a target composition of 40 / 49.87 / 5 / 5 / 0.03 / 0.10 CeO2 / ZrO2 / La2O3 / Y2O3 / SrO / Fe2O3 was prepared by first heating 7.481 kg of ZBC (zirconium basic carbonate), 3.637 kg of (NH4)2[Ce(NO3)6] (cerium ammonium nitrate), 28 L of DI H2O (deionized water), and 10 L of 8M HNO3 (nitric acid) at 55 to 65°C for 1 hour.

[0116] As a second step, a mixture of 0.545 kg of La2(CO3)3 (lanthanum carbonate), 0.475 kg of Y2(CO3)3 (yttrium carbonate), 0.0032 kg of Sr(NO3)2 (strontium nitrate), and 0.0308 kg of Fe(NO3)3·9H2O (iron(III) nitrate nonhydrate) dissolved in 5.0 L of 8M HNO3 (nitric acid) and 2.6 L of DI H2O (deionized water) was added to the first step. Subsequently, a mixed rare-earth zirconium nitrate solution was added to 63 L of DI H2O (deionized water), 31.5 L of NH4OH (ammonium hydroxide, 25% aqueous NH3 solution), and 3.0 kg of C 12 H 24 It was precipitated with a mixture of O2 (lauric acid). The final pH was controlled to be between 9.5 and 10.0. Continuous mixing was performed throughout the entire process. Subsequently, the final precipitate was filtered, washed, and calcined at 750°C to 1000°C, with 950±50°C being preferable. The material was then milled to a final particle size D90 ≤ 20 μm.

[0117] Further details are described in the summary of Examples 1 to 7 below.

[0118] summation: Examples (Example) Characterization of compositions 1 to 7

[0119] The compositions of Examples 1 to 7 were characterized as described below. Data and composition analysis are also provided.

[0120] The compositional content of the compositions of Examples 1 to 7 was measured by ICP spectroscopy. The compositions were analyzed by XRD after aging in air at 1000°C / 10 hours, and the BET specific surface area was measured for the compositions as prepared (i.e., fresh) and after aging / heating in air at 1100°C / 10 hours and at 1100°C / 10 hours. These additional aging (heating) treatments are performed at specified times and temperatures in specified atmospheres. Particle size was also measured. Table 1 below summarizes these results.

[0121] division XRD award 1100℃ in air / 10h furtherance D90 (㎛) SA BET method (m 2 / g) CeO 2 ZrO 2 La 2 O 3 Y 2 O 3 SrO Fe 2 O 3 Fresh in the air 1000℃ / 10h in the air 1100℃ / 10h Example 1 Ce0 . 5Zr0 . 5O2 tetragonal system 40.05 50.24 4.83 4.88 --- --- 8.68 72.7 40.0 25.1 Example 2 Ce0 . 5Zr0 . 5O2 tetragonal system 40.98 49.36 4.41 4.89 0.07 0.29 10.62 61.5 41.3 10.0 Example 3 Ce0 . 5Zr0 . 5O2 tetragonal system 40.62 49.82 4.28 5.00 ----- 0.28 13.96 47.5 30.6 12.3 Example 4 Ce0 . 5Zr0 . 5O2 tetragonal system 40.72 49.96 4.16 4.97 0.04 0.15 8.68 56.4 34.8 16.0 Example 5A Ce0 . 5Zr0 . 5O2, LaFeO3 orthorhombic system 40.84 47.86 4.65 4.88 0.33 1.44 11.05 52.3 9.8 1.8 Example 5B Ce0 . 5Zr0 . 5O2, LaFeO3 orthorhombic system 40.28 49.32 4.79 4.83 0.15 0.63 15.69 49.2 30.3 3.0 Example 7 Ce0 . 5Zr0 . 5O2 tetragonal system 40.40 49.58 5.00 4.90 0.028 0.09 11.83 58.1 40.7 22.3

[0122] Composition analysis confirms the amounts of CeO2, ZrO2, La2O3, Y2O3, SrO, and Fe2O3. XRD is exemplified in Fig. 10 (composition of Example 2), Figs. 13A and 13B (composition of Examples 5A and 5B), and Fig. 17 (composition of Examples 1, 2, 4, and 6). Importantly, XRD analysis confirms that Examples 1, 2, 3, 4, 6, and 7 remain in a tetragonal phase without the detection of a perovskite phase or a pyrochlore phase. In contrast, the XRD of Examples 5A and 5B (Figs. 13A and 13B) demonstrates the presence of perovskite LaFeO3 along with a larger amount of iron contained within these compositions.

[0123] The compositions of Examples 1, 2, 3, 4, 5A, 5B, and 7 were aged / heated in air at 1100°C for 10 hours, and OSC measurements were obtained. The % improvement rate of Examples 2 to 7 compared with Example 1 was calculated. This data is summarized in Table 2 and is shown as a graph in Figure 1.

[0124] division XRD award 1100℃ in air / 10h OSC , in air 1100℃ / 10h Aging ( μmol / g) BET 1100℃ in air / 10h (m 2 / g) Compared to the control group % OSC Improvement rate (1100℃ in air / 10h Aging (μmol / g) Temperature ℃ Temperature ℃ 300 350 450 600 300 350 450 600 Example 1 Ce0 . 5Zr0 . 5O2 tetragonal system 3 16 62 133 25.11 ---- ---- ---- ---- Example 2 Ce0 . 5Zr0 . 5O2 tetragonal system 25 66 126 148 10.03 733% 300% 103% 11% Example 3 Ce0 . 5Zr0 . 5O2 tetragonal system 23 47 105 136 12.31 667% 188% 69% 2% Example 4 Ce0 . 5Zr0 . 5O2 tetragonal system 12 39 95 140 15.95 300% 135% 52% 5% Example 5A Ce0 . 5Zr0 . 5O2 tetragonal system, LaFeO3 orthorhombic system 19 47 111 144 1.78 533% 183% 80% 8% Example 5B Ce0 . 5Zr0 . 5O2 tetragonal system, LaFeO3 orthorhombic system 21 55 117 140 2.96 600% 234% 89% 5% Example 7 Ce0.5Zr0.5O2 tetragonal system 13 33 82 120 22.33 333% 101% 32% -10%

[0125] Table 2 shows the % OSC improvement rates of Examples 2 and 4 compared to Example 1, which is compositionally comparable but does not contain SrO and Fe2O3 (i.e., the amount of ZrO2 was slightly adjusted for the addition of SrO and Fe2O3, but otherwise the composition is identical within experimentally acceptable error / variation). The disclosed compositions containing the mixture of SrO and Fe2O3 (Examples 2 and 4) exhibit superior OSC (particularly at lower temperatures) compared to Comparative Example 1. Example 2 also demonstrates superior OSC characteristics compared to Comparative Example 3 (no SrO) and Example 5A (a larger amount of Fe2O3 resulting in perovskite formation and sintering), as well as Example 5B (a slightly larger amount of Fe2O3 resulting in perovskite formation and sintering).

[0126] Figure 1 and Table 2 demonstrate that the composition of Example 2 containing the disclosed mixture of SrO and Fe2O3 has the highest OSC. Note that a 300% increase is a relative increase of 3 times or becomes 4 times, a 100% increase is a 2-fold increase, and a 200% increase is a relative change of 2 times or becomes 3 times.

[0127] The compositions of Examples 4 and 7 also contain the disclosed mixture of SrO and Fe2O3, but in smaller amounts. Example 7 also exhibits improved thermal stability, exemplified by a high BET specific surface area after aging in air at 1100°C for 10 hours. These observed advantages are based on the starting materials and the process used to prepare the composite oxide, and the resulting OSC formulation can be adjusted based on the amounts of SrO and Fe2O3 contained and the manufacturing method used to produce the composite oxide. The composition of Example 3 contains the same amount of Fe2O3 as in Example 2 but contains no SrO, which demonstrates the importance of SrO in improving OSC (especially at lower temperatures) compared to a composition containing only Fe2O3. The compositions of Example 5A (and Example 5B) containing a larger amount of Fe2O3 do not show the overall improved results of Examples 2 and 4 due to the sintering effect (BET loss) caused by the formation of LaFeO3 perovskite detected by XRD. Therefore, these results demonstrate the importance of using the claimed mixture of SrO and Fe2O3 to improve OSC, especially at lower temperatures.

[0128] OSC measurements were obtained after aging / heating the compositions of Examples 1 to 3 in air at 1150°C / 6 hours, and the % improvement rate of Examples 2 and 3 compared to Example 1 was calculated. This data is summarized in Table 3, and the OSC data is presented as a graph as exemplified in Figure 2. BET measurements after aging / heating in air at 1100°C / 10 hours and 1150°C / 6 hours are also summarized.

[0129] division XRD award 1150℃ in air / 6h OSC , 1150℃ / 6h air aging ( μmol / g) BET 1100℃ in air / 10h (m 2 / g) BET 1150℃ in air / 6h (m 2 / g) Compared to the control group % OSC Improvement rate (1150℃ in air / 6h Aging ( μmol / g)) Temperature ℃ Temperature ℃ 350 450 600 350 450 600 Examples 1 Ce0 . 5Zr0 . 5O2, tetragonal system 13 52 134 25.11 15.01 --- --- --- Examples 2 Ce0 . 5Zr0 . 5O2, tetragonal system 43 103 148 10.03 2.06 220% 100% 10% Examples 3 Ce0 . 5Zr0 . 5O2, tetragonal system 41 109 143 12.31 5.33 208% 110% 6%

[0130] The results in Table 3 show that the composition of Example 2 after aging in air at 1150°C for 6 hours was 10 m 2It demonstrates that it has an improved OSC with a BET specific surface area significantly lower than / g.

[0131] The results in Table 3 and the example in Figure 2 demonstrate that the composition of Example 2 (having the disclosed mixture of SrO and Fe2O3) exhibits superior OSC, particularly at low temperatures, compared to the composition of Example 1 (containing no SrO or Fe2O3) even after aging in air at 1150°C for 6 hours. The OSC of Example 2 is maintained at 2 to 3 times higher than that of Example 1.

[0132] Table 4 summarizes the characterization analysis of Examples 1, 3, 4, and 6. In particular, Table 4 demonstrates the effect of changing the precipitating agent used during the preparation of the composition. Table 4 demonstrates that changing the precipitating agent used during the preparation of the composition can affect the pore size. Examples 1, 3, and 4 used NH4OH as the precipitating agent. In contrast, Example 6 has the same composition as Example 4 but used tetramethylammonium hydroxide (TMAOH), a quaternary ammonium hydroxide (QAH), as the precipitating agent.

[0133] OSC measurements were obtained after aging / heating the compositions of Examples 1, 3, 4, and 6 in air at 1100°C for 10 hours. These data are summarized in Table 4 and presented as graphs, as exemplified in Fig. 3. BET specific surface area, BJH pore volume, and BJH pore radius / size (Fig. 4) were measured for the compositions as prepared (i.e., fresh). Particle size was also measured. Table 4 below summarizes all these results.

[0134] division OSC , in air 1100℃ / 10h Aging (μmol / g) D90 particle size (㎛) Fresh BET (m 2 / g) Fresh BJH PV (cm 3 / g) Fresh BJH radius (Å) 350 450 600 Examples 1 (NH 4 OH) 16 62 133 7.40 72.70 0.40 95.80 Examples 3 (NH 4 OH) 47 105 136 13.96 48.52 0.35 118.37 Examples 4 (NH 4 OH) 39 95 140 8.68 57.16 0.32 120.54 Examples 6 (TMAOH) 38 91 132 12.28 62.26 0.36 75.53

[0135] The results in Table 4 and the example in Figure 3 demonstrate that after aging in air at 1100°C for 10 hours, the compositions of Examples 4 and 6 (containing the disclosed mixture of SrO and Fe2O3) exhibit superior OSC (approximately twice, especially at low temperatures) compared to the composition of Example 1 (containing no SrO or Fe2O3).

[0136] The data in Table 4 and the example in Figure 4 also demonstrate that changing the precipitating agent used during the preparation of the composition can affect the pore size. As described above, the material of Example 6 has the same composition as Example 4, the only difference being the precipitating agent used (Example 6 uses TMAOH). This demonstrates the effect of TMAOH on pore size and indicates that the use of primary, secondary, tertiary, and quaternary ammonium hydroxides can be used to increase pore size without negatively affecting other physical properties.

[0137] The compositions of Examples 2, 5A and 5B were further characterized by TEM, EDS, and XRD as described above and further described below.

[0138] Figure 9 shows a TEM image of the composition of Example 2 after aging / heating in air at 1100°C / 10 hours. Figure 9 demonstrates that the crystallites remain small even after aging in air at 1100°C / 10 hours, while the BET specific surface area and OSC remain high as described above. These results demonstrate the significant effect of the currently disclosed mixture of SrO and Fe2O3. As described above, the XRD of Example 2 (exemplified in Figure 10) confirms that no other highly crystalline phases, such as perovskite or pyrochlore, are present. The XRD of Example 2 confirms that the composition remains tetragonal.

[0139] Figure 11 shows EDS images of the composition of Example 2 after aging / heating in air at 1100°C / 10 hours. The EDS images also do not indicate the presence of any perovskite formation (refer to the Sr, Fe, and La maps—only highly dispersed La2O3 was detected in these images).

[0140] FIG. 12 shows a TEM image of the composition of Example 5A after aging / heating in air at 1100°C / 10 hours. Example 5A is outside the scope of the claims because it contains a larger amount of Fe2O3, and Example 5B also contains a larger amount of Fe2O3. As illustrated in FIG. 12, the disclosed amount of Fe2O3 is significant when compared to FIG. 9. Comparing FIG. 12 (TEM image of Example 5A) with FIG. 9 (TEM image of Example 2), it can be seen that the composition of Example 5A is highly sintered under the same aging conditions. This result is attributed to the presence of a perovskite phase acting as a sintering aid.

[0141] As described above, the XRDs of Examples 5A and 5B (Figs. 13A and 13B) also confirm the presence of perovskite LaFeO3 along with a larger amount of iron contained within these compositions. The list of XRD peaks for Example 5B and Fig. 13B is as follows:

[0142]

[0143]

[0144] The presence of perovskite LaFeO3 is significant because it acts as a sintering aid, causing the composite oxide compositions of Examples 5A and 5B to sinter. Although the OSC of Examples 5A and 5B is maintained higher than that of Example 1, the loss of BET specific surface area begins to have a negative effect on the OSC, resulting in a non-linear OSC response compared to the composite oxide composition containing a mixture of SrO and Fe2O3.

[0145] FIG. 14 shows an EDS image of the composition of Example 5A after aging / heating in air at 1100°C / 10 hours. The EDS image confirms that La, Fe, and Sr formed aggregate regions (see Sr, Fe, and La maps). This indicates a highly crystalline LaFeO3-type perovskite. As described herein, the formation of the perovskite phase is detrimental as it acts as a sintering aid. This should be compared with FIG. 11 (EDS image for the composition of Example 2), which does not show the presence of any perovskite formation.

[0146] H2TPR data were obtained for the slurries of Examples 1, 2, 4, and 6 as prepared (i.e., fresh) and after aging / heating in air at 1100°C / 4 hours. Figures 15A and 15B present this data graphically, indicating that all peaks are unimode and symmetric. Figure 15A demonstrates that the compositions as prepared (i.e., fresh) follow this trend, with Example 2 having a lower light-off temperature than Examples 4 and 6 (which are approximately identical to each other), and all three (Examples 2, 4, and 6) having lower peak temperatures than Example 1. Even after aging / heating in air at 1100°C / 4 hours, the H2TPR data maintains the trend, with Example 2 having a lower light-off temperature than Examples 4 and 6 (which are approximately the same), and all three of these (Examples 2, 4, and 6) having a lower temperature than Example 1.

[0147] OSC measurements were obtained after aging / heating the compositions of Examples 1, 2, 4, and 6 in air at 1100°C / 10 hours. These data are summarized in Table 5 and presented as graphs, as exemplified in Fig. 16. The BET specific surface area for the heated / aged compositions was also measured and is summarized in Table 5. These OSC data are presented for comparison with H2TPR data.

[0148] OSC data for comparison with H2TPR data Sample ID OSC , in air 1100℃ / 10h Aging (μmol / g) BET 1100℃ in air / 10h OSC , control group % Improvement rate 350℃ 450℃ 600℃ 350℃ 450℃ 600℃ Examples 1 16 62 133 25.11 --- --- --- Examples 2 66 126 148 10.03 313% 103% 11% Examples 4 39 95 140 15.95 144% 53% 5% Examples 6 38 91 132 11.78 138% 47% -1%

[0149] The data summarized in Table 5 and illustrated in Figure 16 demonstrate the same improvement trend as the H2TPR results: Example 2 has the most improved OSC (especially at lower temperatures), Examples 6 and 4 have improved and similar OSCs (especially at lower temperatures), and Comparative Example 1 has the lowest OSC (especially at lower temperatures) - the OSC of all compositions levels out as the temperature approaches 600°C.

[0150] Importantly, as can be seen from the OSC data compared with the H2TPR results, the trend of which composition has a higher OSC at a given temperature is opposite to the trend of which composition has a higher H2TPR (i.e., Example 2 has the highest OSC and the lowest H2TPR, while Comparative Example 1 has the lowest OSC and the highest H2TPR). This trend demonstrates that a lower H2TPR reduction temperature is an indicator of a more active OSC material. A lower H2TPR peak temperature demonstrates greater activity and a lower light-off temperature, and is an indicator of an improved low-temperature OSC.

[0151] Table 6 summarizes the H2TPR data for the compositions of Examples 1, 2, 4, and 6 as prepared (i.e., fresh) and after aging / heating in air at 1100°C / 4 hours. Table 6 also summarizes the BET and XRD for Examples 1, 2, 4, and 6 after aging / heating at 1000°C / 10 hours using CO / O2 rich / lean atmosphere cycling.

[0152] H2TPR data table and aged BET and XRD results Sample ID Maximum peak temperature (°C) H 2 Consumption ( μmol / g) CO / O 2 1000℃ for 10 hours Aging BET CO / O 2 1000℃ for 10 hours Aging XRD Examples 1 Fresh 568 1079 31.87 Tetragonal CZO Examples 1 1100℃ / 4 hours 593 1001 31.87 Tetragonal CZO Examples 2 Fresh 491 937 16.38 Tetragonal CZO Examples 2 1100℃ / 4 hours 442 875 16.38 Tetragonal CZO Examples 4 Fresh 534 972 24.21 Tetragonal CZO Examples 4 1100℃ / 4 hours 507 954 24.21 Tetragonal CZO Examples 6 Fresh 528 944 22.75 Tetragonal CZO Examples 6 1100℃ / 4 hours 507 951 22.75 Tetragonal CZO

[0153] The XRD results summarized in Table 6 and illustrated in Fig. 17 (comparison of Examples 1, 2, 4 and 6) confirm that Examples 1, 2, 4 and 6 remain in a tetragonal phase without any perovskite or pyrochlore phase being detected even after a more severe aging cycle, 1000°C / 10 hours CO / O2-rich / lean aging.

[0154] Examples 8: SrO and Fe 2 O 3 second including Seria Zirconia Preparation of a composition

[0155] A 6.0 kg batch of ceria zirconia with a target composition of 40 / 49.3 / 5 / 5 / 0.2 / 0.5 CeO2 / ZrO2 / La2O3 / Y2O3 / SrO / Fe2O3 is first prepared by dissolving 7.395 kg of ZBC (zirconium basic carbonate), 3.636 kg of Ce(OH)4 (cerium(IV) hydroxide), and 0.475 kg of Y2(CO3)3 (yttrium carbonate) in a mixture of 28 L of DI H2O (deionized water) and 15 L of 8 M HNO3 (nitric acid). Subsequently, a mixed rare-earth zirconium nitrate solution is prepared by dissolving 63 L of DI H2O (deionized water), 31.5 L of NH4OH (ammonium hydroxide, 25% aqueous NH3 solution), and 3.0 kg of C 12 H 24 It is precipitated with a mixture of O2 (lauric acid). The final pH of the first step is controlled to be between 9.5 and 10.0.

[0156] As a second step, a mixture of 0.545 kg of La2(CO3)3 (lanthanum carbonate), 0.025 kg of Sr(NO3)2 (strontium nitrate), and 0.152 kg of Fe(NO3)3·9H2O (iron(III) nitrate nonhydrate) dissolved in 1.0 L of 8 M HNO3 (nitric acid) and 2.6 L of DI H2O (deionized water) is added to the precipitate from the first step while controlling the final pH to between 9.5 and 10.0. Continuous mixing is performed throughout the entire process. Subsequently, the final precipitate is filtered, washed, and calcined at 750°C to 1000°C, preferably 950 ± 50°C. The material is then milled to a final particle size D90 ≤ 20 μm.

[0157] Examples 9: SrO and Fe 2 O 3 second including Seria Zirconia Preparation of a composition

[0158] A 6.0 kg batch of ceria zirconia with a target composition of 40 / 49.94 / 5 / 5 / 0.02 / 0.05 CeO2 / ZrO2 / La2O3 / Y2O3 / SrO / Fe2O3 was prepared by first heating 7.490 kg of ZBC (zirconium basic carbonate), 3.636 kg of (NH4)2[Ce(NO3)6] (cerium ammonium nitrate), 28 L of DI H2O (deionized water), and 10 L of 8M HNO3 (nitric acid) at 55 to 65°C for 1 hour.

[0159] As a second step, a mixture of 0.545 kg of La2(CO3)3 (lanthanum carbonate), 0.475 kg of Y2(CO3)3 (yttrium carbonate), 0.00018 kg of Sr(NO3)2 (strontium nitrate), and 0.0152 kg of Fe(NO3)3·9H2O (iron(III) nitrate nonhydrate) dissolved in 5.0 L of 8M HNO3 (nitric acid) and 2.6 L of DI H2O (deionized water) was added to the first step. Subsequently, a mixed rare-earth zirconium nitrate solution was added to 63 L of DI H2O (deionized water), 31.5 L of NH4OH (ammonium hydroxide, 25% aqueous NH3 solution), and 3.0 kg of C 12 H 24 It was precipitated with a mixture of O2 (lauric acid). The final pH was controlled to be between 9.5 and 10.0. Continuous mixing was performed throughout the entire process. Subsequently, the final precipitate was filtered, washed, and calcined at 750°C to 1000°C, with 950±50°C being preferable. The material was then milled to a final particle size D90 ≤ 20 μm.

[0160] Wash coat suspension Examples :

[0161] Comparative example (comparative Example) 10: Examples (Example) 1 of Seria Zirconia using a composition Washcoat's manufacturing

[0162] A washcoat slurry of 6.0 kg based on oxides was prepared by adding 3.75 kg of Example 1, 1.78 kg of La2O3 / Al2O3, 0.55 kg of BaSO4, and 0.09 kg of pseudobermite binder to 6.24 kg of DI water, 0.3 kg of glacial acetic acid, and 0.15 kg of sucrose. The target solid content of the final coating slurry was 43% based on solid content at 1000°C.

[0163] Washcoat was prepared and dried / calcined (at 550°C for 2 hours). Chemical data of the composition can be found in Table 7 below, and physical data of the composition can be found in Table 8 below.

[0164] Subsequently, the dried slurry powder was aged in air at 1100°C for 10 hours, and the OSC was measured according to the method described herein. Table 9 presents the OSC data for the aged composite oxide washcoats for three cases: composite oxide washcoat alone (before PGM addition, i.e., ex-PGM), 1.5 wt% Pd as metal calculated based on washcoat + composite oxide (addition of 301.3 g of Pd-N as a solution supplied with an 18% Pd metal content), and 0.5% Rh as metal calculated based on washcoat + composite oxide (addition of 181.9 g of Rh-N as a solution supplied with a 10% Rh metal content).

[0165] Examples (Example) 11: Examples (Example) 2 of Seria Zirconia using a composition Washcoat's manufacturing

[0166] A washcoat slurry of 6.0 kg based on oxides was prepared by adding 3.75 kg of Example 2, 1.78 kg of La2O3 / Al2O3, 0.55 kg of BaSO4, and 0.09 kg of pseudobermite binder to 6.24 kg of DI water, 0.3 kg of glacial acetic acid, and 0.15 kg of sucrose. The target solid content of the final coating slurry was 43% based on solid content at 1000°C.

[0167] Washcoat was prepared and dried / calcined (at 550°C for 2 hours). Chemical data of the composition can be found in Table 7 below, and physical data of the composition can be found in Table 8 below.

[0168] Subsequently, the dried slurry powder was aged in air at 1100°C for 10 hours, and the OSC was measured according to the method described herein. Table 9 presents the OSC data of the aged composite oxide washcoats described herein for three cases: composite oxide washcoat alone (before PGM addition, i.e., ex-PGM), 1.5 wt% Pd as metal calculated based on washcoat + composite oxide (addition of 301.3 g of Pd-N as a solution supplied with an 18% Pd metal content), and 0.5% Rh as metal calculated based on washcoat + composite oxide (addition of 181.9 g of Rh-N as a solution supplied with a 10% Rh metal content).

[0169] Comparative example (comparative Example) 12: Examples (Example) 3 of Seria Zirconia using a composition Washcoat's manufacturing

[0170] A washcoat slurry of 6.0 kg based on oxides was prepared by adding 3.75 kg of Example 3, 1.78 kg of La2O3 / Al2O3, 0.55 kg of BaSO4, and 0.09 kg of pseudobermite binder to 6.24 kg of DI water, 0.3 kg of glacial acetic acid, and 0.15 kg of sucrose. The target solid content of the final coating slurry was 43% based on solid content at 1000°C.

[0171] Washcoat was prepared and dried / calcined (at 550°C for 2 hours). Chemical data of the composition can be found in Table 7 below, and physical data of the composition can be found in Table 8 below.

[0172] Subsequently, the dried slurry powder was aged in air at 1100°C for 10 hours, and the OSC was measured according to the method described herein. Table 9 presents the OSC data of the aged composite oxide washcoats described herein for three cases: composite oxide washcoat alone (before PGM addition, i.e., ex-PGM), 1.5 wt% Pd as metal calculated based on washcoat + composite oxide (addition of 301.3 g of Pd-N as a solution supplied with an 18% Pd metal content), and 0.5% Rh as metal calculated based on washcoat + composite oxide (addition of 181.9 g of Rh-N as a solution supplied with a 10% Rh metal content).

[0173] Comparative example (comparative Example) 13: Examples (Example) 1 of Seria Zirconia using a composition Washcoat's manufacturing

[0174] A washcoat slurry of 6.0 kg based on oxides was prepared by adding 3.75 kg of Example 1, 1.78 kg of La2O3 / Al2O3, 0.55 kg of BaSO4, and 0.09 kg of pseudobermite binder to 6.24 kg of DI water, 0.3 kg of glacial acetic acid, and 0.15 kg of sucrose. The target solid content of the final coating slurry was 43% based on solid content at 1000°C.

[0175] Washcoat was prepared and dried / calcined (at 550°C for 2 hours). Chemical data of the composition can be found in Table 7 below, and physical data of the composition can be found in Table 8 below.

[0176] Next, the dried slurry powder was aged in air at 1100°C for 10 hours, and the OSC was measured according to the method described herein. Table 10 presents OSC data for aged complex oxide washcoat + 0.23% Rh as metal based on complex oxide (83.2 g of Rh-N added as a solution supplied with 10% Rh metal content).

[0177] Examples (Example) 14: Examples (Example) 2 of Seria Zirconia using a composition Washcoat's manufacturing

[0178] A washcoat slurry of 6.0 kg based on oxides was prepared by adding 3.75 kg of Example 2, 1.78 kg of La2O3 / Al2O3, 0.55 kg of BaSO4, and 0.09 kg of pseudobermite binder to 6.24 kg of DI water, 0.3 kg of glacial acetic acid, and 0.15 kg of sucrose. The target solid content of the final coating slurry was 43% based on solid content at 1000°C.

[0179] Washcoat was prepared and dried / calcined (at 550°C for 2 hours). Chemical data of the composition can be found in Table 7 below, and physical data of the composition can be found in Table 8 below.

[0180] Next, the dried slurry powder was aged in air at 1100°C for 10 hours, and the OSC was measured according to the method described herein. Table 10 presents OSC data for 0.23% Rh as a metal (83.2 g of Rh-N added with 10% Rh content) based on the aged complex oxide washcoat + complex oxide.

[0181] Comparative example (comparative Example) 15: Examples (Example) 3 of Seria Zirconia using a composition Washcoat's manufacturing

[0182] A washcoat slurry of 6.0 kg based on oxides was prepared by adding 3.75 kg of Example 3, 1.78 kg of La2O3 / Al2O3, 0.55 kg of BaSO4, and 0.09 kg of pseudobermite binder to 6.24 kg of DI water, 0.3 kg of glacial acetic acid, and 0.15 kg of sucrose. The target solid content of the final coating slurry was 43% based on solid content at 1000°C.

[0183] Washcoat was prepared and dried / calcined (at 550°C for 2 hours). Chemical data of the composition can be found in Table 7 below, and physical data of the composition can be found in Table 8 below.

[0184] Next, the dried slurry powder was aged in air at 1100°C for 10 hours, and the OSC was measured according to the method described herein. Table 10 presents OSC data for aged complex oxide washcoat + 0.23% Rh as metal based on complex oxide (83.2 g of Rh-N added as a solution supplied with 10% Rh metal content).

[0185] Washcoat's Characteristics Summary

[0186] The composition content of the washcoats of Examples 10 to 15 is summarized in Table 7 below.

[0187] Washcoat formation catalyst Wash coat division, Complex Oxide (MO) Standard PGM furtherance, % Wash coat Solid content criteria and complex oxide (MO) criteria complex oxide La / Al2O3 BaSO4 Pseudobemite %Pd(washcoat) %Rh(washcoat) total %Pd / complex oxide %Rh / complex oxide Examples 10 (Ex-PGM) 40 / 50 / 5 / 5, CeO 2 / ZrO 2 / La 2 O 3 / Y 2 O 3 60.85% 29.02% 9.13% 1.00% --- --- 100.00% --- --- Examples Based on 10 + 1.5% Pd / MO, 40 / 50 / 5 / 5, CeO 2 / ZrO 2 / La 2 O 3 / Y 2 O 3 60.30% 28.75% 9.05% 1.00% 0.90% ----- 100.00% 1.50% ----- Examples Based on 10 + 0.5% Rh / MO, 40 / 50 / 5 / 5, CeO 2 / ZrO 2 / La 2 O 3 / Y 2 O 3 60.67% 28.93% 9.10% 1.00% ----- 0.30% 100.00% ----- 0.50% Examples 11 (Ex-PGM), 40 / 49.56 / 5 / 5 / 0.09 / 0.35, CeO 2 / ZrO 2 / La 2 O 3 / Y 2 O 3 / SrO / Fe 2 O 3 60.85% 29.02% 9.13% 1.00% ----- ----- 100.00% ----- ----- Examples Based on 11 + 1.5% Pd / MO, 40 / 49.56 / 5 / 5 / 0.09 / 0.35, CeO 2 / ZrO 2 / La 2 O 3 / Y 2 O 3 / SrO / Fe 2 O 3 60.30% 28.75% 9.05% 1.00% 0.90% ----- 100.00% 1.50% ----- Examples Based on 11 + 0.5% Rh / MO, 40 / 49.56 / 5 / 5 / 0.09 / 0.35, CeO 2 / ZrO 2 / La 2 O 3 / Y 2 O 3 / SrO / Fe 2 O 3 60.67% 28.93% 9.10% 1.00% ----- 0.30% 100.00% ----- 0.50% Examples 12 (Ex-PGM), 40 / 49.67 / 5 / 5 / 0.33, CeO 2 / ZrO 2 / La 2 O 3 / Y 2 O 3 / Fe 2 O 3 60.85% 29.02% 9.13% 1.00% ----- ----- 100.00% ----- ----- Examples Based on 12 + 1.5% Pd / MO, 40 / 49.67 / 5 / 5 / 0.33, CeO 2 / ZrO 2 / La 2 O 3 / Y 2 O 3 / Fe 2 O 3 60.30% 28.75% 9.05% 1.00% 0.90% ----- 100.00% 1.50% ----- Examples Based on 12 + 0.5% Rh / MO, 40 / 49.67 / 5 / 5 / 0.33, CeO 2 / ZrO 2 / La 2 O 3 / Y 2 O 3 / Fe 2 O 3 60.67% 28.93% 9.10% 1.00% ----- 0.30% 100.00% ----- 0.50% Examples Based on 13 + 0.23% Rh / MO, 40 / 50 / 5 / 5, CeO 2 / ZrO 2 / La 2 O 3 / Y 2 O 3 60.77% 28.97% 9.12% 1.00% ----- 0.14% 100.00% ----- 0.23% Examples Based on 14 + 0.23% Rh / MO, 40 / 49.56 / 5 / 5 / 0.09 / 0.35 CeO 2 / ZrO 2 / La 2 O 3 / Y 2 O 3 / SrO / Fe 2 O 3 60.77% 28.97% 9.12% 1.00% ----- 0.14% 100.00% ----- 0.23% Examples Based on 15 + 0.23% Rh / MO, 40 / 49.67 / 5 / 5 / 0.33, CeO 2 / ZrO 2 / La 2 O 3 / Y 2 O 3 / Fe 2 O 3 60.77% 28.97% 9.12% 1.00% ----- 0.14% 100.00% ----- 0.23%

[0188] Table 8 summarizes the solid content, pH, and viscosity of the washcoat slurries of Examples 10 to 15. Table 8 also provides the particle size distribution of these washcoats after drying / calcining (at 550°C for 2 hours). Table 8 also summarizes the SA BET of the dried slurry powders of the washcoats of Examples 10 to 15 after aging in air at 1100°C for 10 hours.

[0189] Physical properties of washcoat / slurry catalyst Wash coat division % Solid content pH viscosity (cp @ 300 / s) Particle size distribution SA BET method 1100℃ in air / 10h D10 D50 D90 Examples 10 (Ex- PGM ) 40 / 50 / 5 / 5, CeO 2 / ZrO 2 / La 2 O 3 / Y 2 O 3 42.8% 4.67 60.4 2.59 5.02 9.24 30.07 Examples Based on 10 + 1.5% Pd / MO, 40 / 50 / 5 / 5, CeO 2 / ZrO 2 / La 2 O 3 / Y 2 O 3 43.3% 4.31 275.5 2.40 4.88 9.29 30.31 Examples Based on 10 + 0.5% Rh / MO, 40 / 50 / 5 / 5, CeO 2 / ZrO 2 / La 2 O 3 / Y 2 O 3 42.4% 4.45 108.9 2.58 4.95 8.97 29.82 Examples 11 (Ex- PGM ), 40 / 49.56 / 5 / 5 / 0.09 / 0.35, CeO 2 / ZrO 2 / La 2 O 3 / Y 2 O 3 / SrO / Fe 2 O 3 43.7% 4.85 126.0 2.65 5.44 10.61 30.95 Examples Based on 11 + 1.5% Pd / MO, 40 / 49.56 / 5 / 5 / 0.09 / 0.35, CeO 2 / ZrO 2 / La 2 O 3 / Y 2 O 3 / SrO / Fe 2 O 3 42.7% 4.30 464.7 2.78 5.34 9.89 28.65 Examples Based on 11 + 0.5% Rh / MO, 40 / 49.56 / 5 / 5 / 0.09 / 0.35, CeO 2 / ZrO 2 / La 2 O 3 / Y 2 O 3 / SrO / Fe 2 O 3 43.1% 4.40 259.6 2.68 5.41 10.50 29.54 Examples 12 (Ex- PGM ), 40 / 49.67 / 5 / 5 / 0.33, CeO 2 / ZrO 2 / La 2 O 3 / Y 2 O 3 / Fe 2 O 3 43.3% 4.88 91.0 2.72 5.82 11.89 29.49 Examples Based on 12 + 1.5% Pd / MO, 40 / 49.67 / 5 / 5 / 0.33, CeO 2 / ZrO 2 / La 2 O 3 / Y 2 O 3 / Fe 2 O 3 43.3% 4.25 110.2 2.58 5.54 11.76 29.05 Examples Based on 12 + 0.5% Rh / MO, 40 / 49.67 / 5 / 5 / 0.33, CeO 2 / ZrO 2 / La 2 O 3 / Y 2 O 3 / Fe 2 O 3 43.6% 4.40 151.4 2.57 5.70 11.78 29.61 Examples Based on 13 + 0.23% Rh / MO, 40 / 50 / 5 / 5, CeO 2 / ZrO 2 / La 2 O 3 / Y 2 O 3 42.1% 4.94 182.6 2.41 5.12 10.25 28.25 Examples Based on 14 + 0.23% Rh / MO, 40 / 49.56 / 5 / 5 / 0.09 / 0.35 CeO 2 / ZrO 2 / La 2 O 3 / Y 2 O 3 / SrO / Fe 2 O 3 42.3% 4.94 250.3 2.49 5.20 10.43 29.92 Examples Based on 15 + 0.23% Rh / MO, 40 / 49.67 / 5 / 5 / 0.33, CeO 2 / ZrO 2 / La 2 O 3 / Y 2 O 3 / Fe 2 O 3 42.1% 5.00 310.7 2.68 5.73 11.73 28.43

[0190] As described, the exemplary washcoats were dried / calcined (at 550°C for 2 hours) and then the dried slurry powders of the washcoats of Examples 10 to 12 were aged in air at 1100°C for 10 hours. After aging / heating the washcoats of Examples 10 to 12 in air at 1100°C for 10 hours, OSC measurements were obtained, and the % improvement rate of Examples 11 and 12 compared to Example 10 was calculated. This data is summarized in Table 9, and the data were graphed as exemplified in Figures 5 (no PGM / ex-PGM), 6 (based on 1.5 wt% Pd / MO), and 7 (based on 0.5 wt% Rh / MO).

[0191] Table 9: Washcoat OSC data, Examples 10 to 12 (aging in air at 1100°C / 10 hours (μmol / g))

[0192]

[0193] The results in Table 9 and the example in Figure 5 show the OSC of a dried washcoat without PGM addition (Ex-PGM) after aging in air at 1100°C for 10 hours. Example 10 used the composite oxide of Comparative Example 1, which contains no SrO or Fe2O3. Example 11 used the composite oxide of Example 2 (having the disclosed mixture of SrO and Fe2O3). Example 12 used the composite oxide of Comparative Example 3, which contains no SrO. Example 11 exhibits superior OSC over both Examples 10 and 11 across the test temperature range (200°C to 450°C), demonstrating that the currently disclosed composition has unexpectedly improved low-temperature OSC.

[0194] The results in Table 9 and the example in Fig. 6 represent the OSC of a dried washcoat with 1.5 wt% Pd added as a metal based on the composite oxide after aging in air at 1100°C / 10 hours. Example 10 used the composite oxide of Comparative Example 1, which contains no SrO or Fe2O3. Example 11 used the composite oxide of Example 2 (having the disclosed mixture of SrO and Fe2O3). Example 12 used the composite oxide of Comparative Example 3, which contains no SrO. Fig. 6 demonstrates that 1.5 wt% Pd activated the OSC material compared to the PGM-free material exemplified in Fig. 5.

[0195] The results in Table 9 and the example in Figure 7 represent the OSC of a dried washcoat with 0.5 wt% Rh added as a metal based on the composite oxide after aging in air at 1100°C / 10 hours. Example 10 used the composite oxide of Comparative Example 1, which contains no SrO or Fe2O3. Example 11 used the composite oxide of Example 2 (having the disclosed mixture of SrO and Fe2O3). Example 12 used the composite oxide of Comparative Example 3, which contains no SrO. Example 11 exhibits superior OSC over both Examples 10 and 11 across the test temperature range (200°C to 450°C), demonstrating that the currently disclosed composition has unexpectedly improved low-temperature OSC.

[0196] As described, the exemplary washcoats of Examples 13 to 15 were dried / calcined (at 550°C for 2 hours), and then the dried slurry powders of these washcoats were aged in air at 1100°C for 10 hours. After aging / heating the washcoats of Examples 13 to 15 in air at 1100°C for 10 hours, OSC measurements were obtained, and the % improvement rate of Examples 14 and 15 compared to Example 13 was calculated. This data is summarized in Table 10, and the data is presented graphically as exemplified in Fig. 8 (based on 0.23 wt% Rh / MO).

[0197] Dry / calcined washcoat OSC data, based on 0.23% Rh / complex oxide (MO). catalyst Wash coat division % Rh / MO 0.23% Rh / MO standard slurry, aging in air at 1100℃ / 10h ( μmol / g) % Improvement rate, aging in air at 1100℃ / 10h ( μmol / g) Temperature ℃ 0.23 Rh / complex oxide (MO) Temperature ℃ 200 250 300 350 450 250 350 450 Examples 13 0.23% 0.22 6.07 29.07 67.70 110.12 --- --- --- Examples 14 0.23% 4.72 13.08 42.37 81.90 115.45 116% 21% 5% Examples 15 0.23% 1.37 12.5 39.65 79.64 111.49 106% 18% 1%

[0198] The results in Table 10 and the example in Figure 8 show the OSC of a dried washcoat with 0.23 wt% Rh added as a metal based on the composite oxide after aging in air at 1100°C / 10 hours. Example 13 used the composite oxide of Comparative Example 1, which contains no SrO or Fe2O3. Example 14 used the composite oxide of Example 2 (having the disclosed mixture of SrO and Fe2O3). Example 15 used the composite oxide of Comparative Example 3, which contains no SrO. Example 14 exhibits superior OSC over both Examples 13 and 15 across the test temperature range (200°C to 450°C), demonstrating that the currently disclosed composition has unexpectedly improved low-temperature OSC. The OSC value was as expected, with OSC activation decreasing at 0.23 wt% Rh as a metal based on the complex oxide compared to 0.5 wt% Rh as a metal based on the complex oxide.

[0199] Unless otherwise indicated, all numerical values ​​expressing the amount of ingredients, characteristics such as molecular weight, reaction conditions, etc. used in the specification and claims shall be understood as being modified by the term "approximately" in all cases. Accordingly, unless otherwise indicated, numerical parameters presented in the following specification and appended claims are approximations that may vary depending on the desired characteristics to be obtained.

[0200] Although the numerical ranges and parameters presenting the broad scope of this technology are approximations, the figures presented in the specific embodiments are reported as accurately as possible. However, any figure inherently contains a specific error inevitably arising from the standard deviation found in each test measurement.

[0201] It will be apparent that the compositions and methods described herein are suitable for achieving the purposes and benefits mentioned, as well as the purposes and benefits inherent therein. A person skilled in the art will recognize that the methods and systems within this specification may be implemented in various ways and are therefore not limited by the embodiments and examples exemplified above. In this regard, any number of features of the different embodiments described herein may be combined into a single embodiment, and alternative embodiments having fewer or more features than all the features described herein are possible.

[0202] Although various embodiments have been described for the purposes of this disclosure, various changes and modifications may be made within the scope of this disclosure. A number of other modifications that can be easily derived by a person skilled in the art and are included in the spirit of this disclosure may be made.

[0203] Although the invention of the present invention has been described with reference to specific embodiments, it should be understood that these embodiments are merely illustrative of the principles and applications of the invention. Accordingly, it should be understood that numerous modifications may be made to the exemplary embodiments and that other arrangements may be devised without departing from the spirit and scope of the invention as disclosed. Accordingly, the invention is intended to include modifications and variations within the scope of the appended claims and their equivalents.

Claims

Claim 1 A composite oxide composition comprising: a) about 1 to about 45 weight% of cerium based on oxide; b) about 40 to about 98 weight% of zirconium based on oxide; c) about 0.05 weight% to about 0.50 weight% of iron based on oxide; d) about 0.015 weight% to about 0.20 weight% of strontium based on oxide; and e) optionally, an additional rare earth dopant selected from the group consisting of lanthanum, neodymium, yttrium, praseodymium, samarium, gadolinium, and mixtures thereof, wherein, if present, each optional additional rare earth dopant is present in an amount of about 0.5 to about 15 weight% based on oxide. Claim 2 A composite oxide composition comprising: a) cerium in an amount of about 1 to about 45 weight% based on oxide; b) zirconium in an amount of about 40 to about 98 weight% based on oxide; c) iron in an amount of about 0.05 weight% to about 0.50 weight% based on oxide; d) strontium in an amount of about 0.015 weight% to about 0.20 weight% based on oxide; and e) optionally, an additional rare earth dopant selected from the group consisting of lanthanum, neodymium, yttrium, praseodymium, samarium, gadolinium, and mixtures thereof, wherein, if present, each optional additional rare earth dopant is present in an amount of about 0.5 to about 15 weight% based on oxide. Claim 3 A composite oxide composition according to claim 1 or 2, wherein the composite oxide composition comprises: a) about 30 to about 45 weight% of cerium based on oxide; b) about 40 to about 65 weight% of zirconium based on oxide; c) about 0.05 weight% to about 0.50 weight% of iron based on oxide; d) about 0.015 weight% to about 0.20 weight% of strontium based on oxide; and e) additional rare earth dopant selected from the group consisting of lanthanum, yttrium and mixtures thereof and present in an amount of about 5 to about 15 weight% based on oxide, or / or essentially comprises. Claim 4 A composite oxide composition according to any one of claims 1 to 3, wherein the composite oxide composition does not exhibit a perovskite phase or a pyrochlore phase detectable by XRD after aging in air at 1100°C for 10 hours. Claim 5 In any one of claims 1 to 3, the composite oxide composition is approximately 10 m after aging in air at 1100°C for 10 hours 2 / g to about 20 m 2 A complex oxide composition having a BET specific surface area of ​​ / g. Claim 6 A composite oxide composition according to any one of claims 1 to 3, wherein the composite oxide composition has a crystallite size of about 50 nm to about 100 nm after aging in air at 1100°C for 10 hours. Claim 7 A composite oxide composition according to any one of claims 1 to 3, wherein, after aging in air at 1100°C for 10 hours, the composite oxide composition exhibits an oxygen storage capacity (OSC) approximately 2 to 7 times higher at approximately 250°C to approximately 600°C than the same composition not containing a mixture of iron and strontium. Claim 8 A composite oxide composition according to claim 7, wherein the higher oxygen storage capacity (OSC) is at about 250°C to about 450°C. Claim 9 In any one of claims 1 to 3, the composite oxide composition is about 40 m 2 / g to about 80 m 2 / g, preferably 40 to 50 m 2 A complex oxide composition having a BET specific surface area of ​​ / g as manufactured. Claim 10 In any one of claims 1 to 3, the composite oxide composition is approximately 2 m after aging in air at 1150°C for 6 hours. 2 / g greater than or about 10 m 2 A complex oxide composition having a BET specific surface area of ​​less than / g. Claim 11 A composite oxide composition according to claim 10, wherein, after aging in air at 1150°C for 6 hours, the composite oxide composition exhibits an oxygen storage capacity (OSC) approximately 2 to 3 times higher at approximately 250°C to approximately 600°C than the same composition not containing a mixture of iron and strontium. Claim 12 A composite oxide composition according to claim 11, wherein the higher oxygen storage capacity (OSC) is at about 250°C to about 450°C. Claim 13 A composite oxide composition according to any one of claims 10 to 12, wherein the composite oxide composition exhibits a tetragonal or cubic phase without a detectable perovskite or pyrochlore phase when measured by XRD after aging in air at 1150°C for 6 hours. Claim 14 A composite oxide composition according to any one of claims 1 to 3, wherein H2TPR (hydrogen TPR) exhibits a single symmetric reduction peak after aging in air at approximately 1100°C for 4 hours. Claim 15 A composite oxide composition according to any one of claims 1 to 3, wherein, after aging in air at 1100°C for 10 hours, the composite oxide composition exhibits an oxygen storage capacity (OSC) that is about 2 to 4 times higher at about 250°C to about 600°C than the same composition that does not contain a mixture of iron and strontium. Claim 16 A composite oxide composition according to claim 15, wherein the higher oxygen storage capacity (OSC) is at about 250°C to about 450°C. Claim 17 In any one of paragraphs 1 to 3, D of about 6 μm to about 20 μm 90 and D of about 1 μm to about 10 μm 10 A composite oxide composition having a particle size characterized by Claim 18 A composite oxide composition according to any one of claims 1 to 3, wherein the composite oxide composition is essentially composed of CeO2, ZrO2, La2O3, Y2O3, Fe2O3, and SrO. Claim 19 A complex oxide composition according to any one of claims 1 to 3 or 18, essentially comprising CeO2, ZrO2, La2O3, Y2O3, Fe2O3 and SrO, wherein the ratio of Ce / Zr / La / Y / Sr / Fe is approximately 35 wt% to approximately 45 wt% cerium, approximately 45 wt% to approximately 55 wt% zirconium, approximately 3 wt% to approximately 6 wt% lanthanum, approximately 3 wt% to approximately 6 wt% yttrium, approximately 0.03 wt% to approximately 0.2 wt% strontium, and approximately 0.1 wt% to approximately 0.5 wt% iron phosphorus. Claim 20 A catalyst or catalyst composition comprising a composite oxide composition of any one of claims 1 to 19 as an initial feedstock. Claim 21 As a suspension, it comprises (i) a platinum group metal selected from the group consisting of platinum, palladium, rhodium, iridium, osmium, ruthenium and mixtures thereof, and (ii) a complex oxide composition, wherein the complex oxide composition comprises a) about 1 to about 45 weight% of cerium based on oxide; b) about 40 to about 98 weight% of zirconium based on oxide; c) about 0.05 weight% to about 0.50 weight% of iron based on oxide; and d) about 0.015 weight% to about 0.20 weight% of strontium based on oxide; and e) optionally comprising an additional rare earth dopant selected from the group consisting of lanthanum, neodymium, yttrium, praseodymium, samarium, gadolinium and mixtures thereof, wherein, if present, each optional additional rare earth dopant is present in an amount of about 0.5 to about 15 weight percent based on oxides, a suspension. Claim 22 In paragraph 21, a suspension in which the platinum group metal is rhodium or palladium. Claim 23 A suspension according to claim 21 or 22, wherein the suspension comprises about 55% by weight to about 65% by weight of the complex oxide composition. Claim 24 A suspension according to any one of claims 21 to 23, wherein the platinum group metal is rhodium, and the suspension comprises about 0.2 weight% to about 0.50 weight% of rhodium as a metal based on the complex oxide. Claim 25 A suspension according to any one of claims 21 to 23, wherein the platinum group metal is palladium, and the suspension comprises about 0.5 weight% to about 1.50 weight% of palladium as a metal based on the complex oxide. Claim 26 A suspension comprising, in any one of claims 21 to 25, La2O3-doped Al2O3, BaSO4, and pseudobemite. Claim 27 A suspension according to any one of claims 21 to 26, wherein the composite oxide composition essentially comprises: a) cerium in an amount of about 30 to about 45 weight% based on the oxide; b) zirconium in an amount of about 40 to about 65 weight% based on the oxide; c) iron in an amount of about 0.1 weight% to about 0.50 weight% based on the oxide; d) strontium in an amount of about 0.05 weight% to about 0.20 weight% based on the oxide; and e) an additional rare earth dopant selected from the group consisting of lanthanum, yttrium and mixtures thereof and present in an amount of about 5 to about 15 weight% based on the oxide. Claim 28 A suspension according to any one of claims 21 to 27, wherein the composite oxide composition does not exhibit a perovskite phase or a pyrochlore phase detectable by XRD after aging in air at 1100°C for 10 hours. Claim 29 A suspension comprising a carboxylic acid further comprising any one of paragraphs 21 to 28. Claim 30 In paragraph 29, a suspension in which the carboxylic acid is acetic acid. Claim 31 A suspension according to any one of claims 21 to 30, wherein the suspension has a pH of about 4 to about 6. Claim 32 A suspension according to any one of claims 21 to 31, wherein when the suspension is dried and calcined, the dried and calcined suspension exhibits an improved oxygen storage capacity (OSC) at about 250°C to about 600°C compared to a dried and calcined suspension containing a composite oxide composition having the same composition but not containing a mixture of iron and strontium. Claim 33 In paragraph 32, the above-mentioned dried and calcined suspension is a suspension containing rhodium.

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