Low-temperature high-performance oxygen storage material, preparation method and automobile exhaust purification catalyst

Abstract

This application relates to a low-temperature, high-performance oxygen storage material, a preparation method, and an automotive exhaust purification catalyst. The method comprises: preparing a solution A1 containing cerium, zirconium, and a metal-modifying doping element; preparing a solution A2 containing ammonium carbonate and aqueous ammonia; modifying nanoparticles with a silane coupling agent to obtain a slurry A3; titrating and precipitating solutions A1, A2, and A3 together, adding concentrated aqueous ammonia and stirring after the titration to obtain a slurry B; sequentially subjecting slurry B to low-temperature aging and high-temperature aging to obtain a slurry C; heating slurry C to a set temperature, adding concentrated aqueous ammonia and a surfactant to slurry C, and stirring to react to obtain a slurry D; filtering and washing slurry D, and drying and calcining the filter cake obtained by filtration and washing to obtain a low-temperature, high-performance oxygen storage material. This method addresses the problem of relatively poor low-temperature reactivity of oxygen storage materials in related technologies, which makes them incapable of handling low-temperature ignition during the frequent start-stop cycles of hybrid vehicles.

Description

Technical Field

[0001] The present application relates to the technical field of automobile exhaust purification and treatment, and in particular to a low-temperature, high-performance oxygen storage material, a preparation method, and an automobile exhaust purification catalyst. Background Art

[0002] Automobile exhaust purification catalysts are the primary strategy for converting pollutants such as carbon monoxide, hydrocarbons, and nitrogen oxides into non-toxic gases such as carbon dioxide and water vapor. Automobile exhaust purification catalysts generally consist of a honeycomb carrier and a catalytic coating, which is primarily composed of rare earth oxygen storage materials, catalytic materials such as alumina, and precious metal active components. Rare earth oxygen storage materials store oxygen during lean combustion and release oxygen during rich combustion, thereby broadening the operating window of the three-way catalyst and achieving efficient and comprehensive conversion of CO, HC, and NOx. Currently, the most commonly used oxygen storage material is a cerium-zirconium solid solution. Doping with appropriate amounts of rare earths, alkali metals, and transition metals can improve the thermal stability, oxygen storage properties, and redox properties of the cerium-zirconium solid solution.

[0003] Current research focuses on fine-tuning the preparation conditions of oxygen storage materials, including controlling precipitation pH, aging conditions, post-treatment conditions, and the properties of added surfactants. Currently, the main methods for preparing cerium-zirconium solid solutions include co-precipitation, sol-gel, hydrothermal, and high-energy ball milling. Co-precipitation has been widely used due to its simplicity, easily controlled conditions, and ease of industrial production. However, existing co-precipitation processes are complex, and the properties of the cerium-zirconium solid solutions produced by these methods fall short of meeting the requirements of automotive exhaust after-treatment modules. For example, high-temperature resistance requires further improvement, and oxygen storage capacity, thermal stability, and surface area cannot be perfectly matched simultaneously. Furthermore, with the advancement of "dual carbon" (DCE) emissions, hybrid vehicles are increasingly gaining market share, and emissions requirements for hybrid engines are placing new demands on oxygen storage materials. To achieve optimal fuel economy, hybrid vehicles experience frequent starts and stops during operation, compared to conventional combustion engines. These frequent starts and stops and the high number of transient operating conditions require oxygen storage materials to possess not only excellent high-temperature oxygen storage and release properties but also good reactivity at low temperatures.

[0004] Related technologies, such as CN105642269B, disclose a composite cerium-zirconium solid solution and its preparation method. The solution is composed of cerium oxide, zirconium oxide, and a rare earth additive, with the following weight percentages: 15-80% cerium oxide, 15-60% zirconium oxide, and 5-25% rare earth additive. The rare earth additive is one or more of lanthanum oxide, praseodymium oxide, rubidium oxide, yttrium oxide, samarium oxide, terbium oxide, dysprosium oxide, and erbium oxide. Modification with a composite surfactant and carbonization and calcination results in a larger pore size and volume. However, the use of hydrogen peroxide to oxidize the rare earth zirconium mixture during precipitation affects the micromorphology, redox properties, and oxygen storage and release capacity of the cerium-zirconium composite oxide.

[0005] In short, although the existing technology has improved the specific surface area and high-temperature aging performance of oxygen storage materials to a relatively high level, the low-temperature reaction activity of oxygen storage materials is relatively poor and cannot cope with the low-temperature ignition during the frequent start-stop process of hybrid vehicles. Summary of the Invention

[0006] The embodiments of the present application provide a low-temperature, high-performance oxygen storage material, a preparation method, and an automobile exhaust purification catalyst to address the problem in related technologies that the low-temperature reaction activity of oxygen storage materials is relatively poor and cannot cope with the low-temperature ignition problem during the frequent start-stop process of hybrid vehicles.

[0007] In a first aspect, a method for preparing a low-temperature, high-performance oxygen storage material is provided, comprising the following steps:

[0008] Prepare a solution A1, wherein the solution A1 contains cerium, zirconium, and a metal-modified doping element for modifying the cerium and zirconium;

[0009] preparing a solution A2, wherein the solution A2 contains ammonium carbonate and aqueous ammonia;

[0010] The nanoparticles are modified using a silane coupling agent to obtain slurry A3;

[0011] The solution A1, solution A2 and slurry A3 are titrated and precipitated together. After the titration is completed, concentrated ammonia water is added and stirred to obtain slurry B;

[0012] The slurry B is subjected to low-temperature aging treatment and high-temperature aging treatment in sequence to obtain slurry C;

[0013] After heating the slurry C to a set temperature, adding concentrated ammonia water and a surfactant to the slurry C, stirring and reacting, to obtain slurry D;

[0014] The slurry D is filtered and washed, and the filter cake obtained by the filtration and washing is dried and calcined to obtain a low-temperature and high-performance oxygen storage material.

[0015] In some embodiments, the low-temperature, high-performance oxygen storage material comprises, by weight, 20-60% cerium oxide, 30-70% zirconium oxide, 3-15% metal-modified doping aid, and 0.1-3% nanoparticles.

[0016] In some embodiments, solution A1 is prepared, specifically comprising:

[0017] A soluble cerium salt is dissolved in hydrogen peroxide, a soluble zirconium salt is dissolved in a nitric acid aqueous solution, and a soluble salt of a metal-modified doping element is dissolved in hydrogen peroxide, and then the mixture is mixed and stirred uniformly to obtain a solution A1.

[0018] In some embodiments, the soluble cerium salt includes one or more of cerium nitrate and cerium carbonate;

[0019] Soluble zirconium salts include one or more of zirconium nitrate and zirconium carbonate;

[0020] The soluble salt of the metal-modified doping element includes one or more of the nitrate and carbonate of the metal-modified doping element.

[0021] In some embodiments, the metal-modifying doping element includes one or more of aluminum, rare earth elements, transition metal elements, alkali metal elements, and alkaline earth metal elements.

[0022] In some embodiments, solution A2 is prepared, specifically comprising:

[0023] dissolving ammonium carbonate in water to obtain an ammonium carbonate solution;

[0024] The ammonium carbonate solution was mixed with aqueous ammonia to obtain solution A2.

[0025] In some embodiments, the molar ratio of the ammonium carbonate solution to the ammonia solution is 0.5 to 2:1.

[0026] In some embodiments, the nanoparticles are modified with a silane coupling agent to obtain slurry A3, specifically comprising:

[0027] The nanoparticles are added to a solvent and dispersed by ultrasonication, and then a silane coupling agent is added and ultrasonicated to obtain a slurry A3. The amount of the silane coupling agent added is 0.5-2% of the mass of the nanoparticles.

[0028] In some embodiments, the nanoparticles include one or more of nano-silicon dioxide and nano-α-alumina powder.

[0029] In some embodiments, the average particle size of the nanoparticles is 5 to 30 nm.

[0030] In some embodiments, the silane coupling agent includes an amino-hydrocarbon-based silane coupling agent.

[0031] In some embodiments, the amino-hydrocarbon-based silane coupling agent includes one or more of γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-ureapropyltriethoxysilane, and γ-(β-aminoethyl)aminopropyltrimethoxysilane.

[0032] In some embodiments, the low-temperature aging treatment includes: low-temperature aging at 15-25° C. for 3-8 hours.

[0033] In some embodiments, the high temperature aging treatment includes: high temperature aging at 90-98° C. for 2-5 hours.

[0034] In some embodiments, the set temperature is 50-70°C.

[0035] In some embodiments, the surfactant is a mixture of fatty acid and polyvinyl alcohol, or a mixture of carboxylic acid ester and polyvinyl alcohol.

[0036] In some embodiments, the fatty acid comprises one or more of lauric acid, palmitic acid, stearic acid, and oleic acid;

[0037] The carboxylic acid ester includes one or more of Tween 20, Tween 60 and Tween 80.

[0038] In some embodiments, the calcination comprises: heating the temperature to 400-800° C. at a heating rate of 5-20° C. / min, and then calcining for 3-6 hours.

[0039] In a second aspect, a low-temperature, high-performance oxygen storage material is provided, which is prepared using any of the above methods for preparing low-temperature, high-performance oxygen storage materials.

[0040] In a third aspect, an automobile exhaust purification catalyst is provided, which includes the low-temperature, high-performance oxygen storage material as described above.

[0041] The beneficial effects of the technical solution provided by this application include:

[0042] The present invention provides a low-temperature, high-performance oxygen storage material, preparation method, and automobile exhaust purification catalyst. Beyond the early efforts to control the cerium-zirconium ratio and identify suitable doping agents, current research on improving the performance of oxygen storage materials is focused on fine-tuning the preparation conditions, including controlling precipitation pH, aging conditions, post-treatment conditions, and the addition of surfactants. For example, the initial grain size of the nanocrystals can be regulated by taking advantage of the different nucleation rates of nanocrystals corresponding to different precipitants and their different decomposition rates during calcination. Furthermore, the fundamental function of the aging process—crystal refinement (dissolution of small grains and growth of large grains)—can be utilized to optimize aging conditions and control the initial grain size of the nanocrystals.

[0043] This application innovatively proposes to introduce modified nanoparticles as nucleation sites for cerium-zirconium nanocrystals during the co-precipitation stage, allowing the cerium-zirconium precipitate to undergo heterogeneous nucleation, thereby controlling the nucleation and growth of the oxygen storage material and obtaining an oxygen storage material with high oxygen storage capacity and high-temperature aging resistance. It was also unexpectedly discovered that the oxygen storage material prepared by this method also has excellent oxygen storage and release performance (i.e., reaction activity) under low-temperature conditions (as low as 250°C), which is of great significance for the emission requirements of hybrid vehicles. Compared with the previous process that required precise control of pH value, aging conditions, post-processing conditions, etc. during the preparation process, the introduction of modified nanoparticles can significantly reduce the processing difficulty of oxygen storage materials and improve product consistency.

[0044] Nanoparticles serve as nucleation sites for cerium-zirconium nanocrystals. Since they are prone to agglomeration, the purpose of modification is to prevent nanoparticle agglomeration and promote dispersion, which is beneficial to the nucleation growth of oxygen storage materials. At the same time, the introduction of silicon can also improve the performance of oxygen storage materials.

[0045] Through extensive research, the applicant discovered that modified silica and α-alumina can produce the above-mentioned effects. However, experiments have shown that the corresponding modified γ-alumina cannot perform well. This may be because γ-alumina has poor thermal stability and undergoes phase transformation and sintering during the roasting process, resulting in structural collapse and degradation of the performance of the oxygen storage material.

[0046] After low-temperature and high-temperature aging, the present invention is cooled to room temperature. Compared with the room-temperature aging of the prior art, the low-temperature aging method can reduce the nucleation of the cerium-zirconium compound itself, and preferentially nucleate the modified nanoparticles. The low-temperature aging period allows all the grains in the system to nucleate and grow uniformly.

[0047] The present application adopts an amino-hydrocarbon-based silane coupling agent because it can be decomposed during the subsequent calcination process without introducing other impurities, and the gas generated by the decomposition can promote the formation of a porous structure.

[0048] Since the oxygen storage performance of Ce-Zr oxygen storage materials comes from Ce 3+ and Ce 4+ The reversible redox (oxygen storage and release) cycle is essentially determined by the unique electronic configuration of Ce. In fact, the oxygen storage / release process of Ce-Zr oxygen storage materials is carried out step by step in the order of surface-bulk phase. Among them, gaseous oxygen can quickly fill the surface oxygen vacancies at room temperature. Therefore, the key steps that determine the oxygen storage performance of Ce-Zr oxygen storage materials are the formation of oxygen vacancies and the migration and diffusion of oxygen species. The role of introducing metal modified doping elements is as follows: 1) The introduced doping ions will replace Ce in the lattice 4+ and Zr 4+ , due to the doping ions and Ce 4+ and Zr 4+The difference in radius will cause the unit cell to shrink or expand, and this process will lead to the formation of structural defects related to cations; 2) Since the valence state of the doped ions is relatively low (usually +2 or +3), more oxygen vacancies will be generated in the lattice to maintain electrical neutrality; 3) It can effectively stabilize the phase structure, reduce the sintering rate of the material, and improve its thermal stability; 4) It can increase the specific surface area of the material. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0050] Figure 1 Flowchart of the preparation method of the low-temperature, high-performance oxygen storage material provided in the embodiments of the present application. DETAILED DESCRIPTION

[0051] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0052] Beyond the early efforts to control the cerium-zirconium ratio and identify suitable doping agents, current research on improving the performance of oxygen storage materials is focused on fine-tuning the preparation conditions, including controlling precipitation pH, aging conditions, post-treatment conditions, and the addition of surfactants. For example, the initial grain size of the nanocrystals can be manipulated by taking advantage of the varying nucleation rates of different precipitants and their decomposition rates during calcination. Furthermore, the fundamental function of the aging process—crystal refinement (dissolution of small grains and growth of larger ones)—can be exploited to optimize aging conditions and control the initial grain size of the nanocrystals.

[0053] This application innovatively proposes to introduce modified nanoparticles as nucleation sites for cerium-zirconium nanocrystals during the co-precipitation stage, allowing the cerium-zirconium precipitate to undergo heterogeneous nucleation, thereby controlling the nucleation and growth of the oxygen storage material and obtaining an oxygen storage material with high oxygen storage capacity and high-temperature aging resistance. It was also unexpectedly discovered that the oxygen storage material prepared by this method also has excellent oxygen storage and release performance (i.e., reaction activity) under low-temperature conditions (as low as 250°C), which is of great significance for the emission requirements of hybrid vehicles. Compared with the previous process that required precise control of pH value, aging conditions, post-processing conditions, etc. during the preparation process, the introduction of modified nanoparticles can significantly reduce the processing difficulty of oxygen storage materials and improve product consistency.

[0054] Specifically, see Figure 1 As shown, the present invention provides a method for preparing a low-temperature, high-performance oxygen storage material, which includes the following steps:

[0055] 101: Prepare solution A1, wherein the solution A1 contains cerium, zirconium, and a metal-modified doping element for modifying cerium and zirconium.

[0056] Solution A2 is prepared, wherein the solution A2 contains ammonium carbonate and ammonia water.

[0057] The nanoparticles were modified with a silane coupling agent to obtain slurry A3.

[0058] 102: The solution A1, solution A2 and slurry A3 are titrated and precipitated together. After the titration is completed, concentrated ammonia water is added and stirred to obtain slurry B.

[0059] In step 102, during titration, the temperature is set at 30-40° C., that is, solution A1, solution A2, and slurry A3 are titrated at 30-40° C. After adding concentrated ammonia water, stir for 1-2 hours to ensure thorough mixing.

[0060] The concentrated ammonia water is used at a conventional concentration, such as 25-28%, mainly to provide hydroxyl groups and regulate pH so that the metal ions are completely precipitated. The use of ammonia water can avoid the introduction of new metal ions.

[0061] 103: The slurry B is subjected to low-temperature aging treatment and high-temperature aging treatment in sequence to obtain slurry C.

[0062] Wherein, the low-temperature aging treatment includes: low-temperature aging at 15-25°C for 3-8 hours.

[0063] The high-temperature aging treatment includes: high-temperature aging at 90-98° C. for 2-5 hours.

[0064] After low-temperature and high-temperature aging, the system is cooled to room temperature. Compared to the existing room-temperature aging, the low-temperature aging method reduces nucleation in the cerium-zirconium compound itself, prioritizing nucleation on the modified nanoparticles. The low-temperature aging allows for uniform nucleation and growth of all grains in the system.

[0065] 104: After the slurry C is heated to a set temperature, concentrated ammonia water and a surfactant are added to the slurry C, and the mixture is stirred for reaction to obtain slurry D.

[0066] The set temperature is 50-70° C. The mixture is stirred for 1-3 hours and then cooled to room temperature.

[0067] The set temperature is set at 50-70°C because surfactants are subsequently added. On the one hand, they reduce the surface tension of water within the material's pores by lowering interfacial energy, significantly reducing shrinkage and collapse of the network structure during drying and calcination. On the other hand, surfactants act as dispersants, adsorbing on the surface of solid particles. When the adsorption layer reaches a certain thickness, it generates sufficient repulsive energy to overcome the attraction between the particles, thus achieving dispersion. Therefore, a relatively suitable temperature is required. Lower temperatures will prolong the adsorption process, while higher temperatures will lead to unstable structures.

[0068] The concentrated ammonia water adopts a conventional concentration, such as 25-28%, mainly to provide hydroxyl groups and regulate pH so that the metal ions are completely precipitated; the use of ammonia water can avoid the introduction of new metal ions.

[0069] The surfactant is a mixture of fatty acid and polyvinyl alcohol, or a mixture of carboxylic acid ester and polyvinyl alcohol.

[0070] The fatty acid includes one or more of lauric acid, palmitic acid, stearic acid and oleic acid;

[0071] The carboxylic acid ester includes one or more of Tween 20, Tween 60 and Tween 80.

[0072] 105: The slurry D is filtered and washed, and the filter cake obtained by the filtration and washing is dried and calcined to obtain a low-temperature, high-performance oxygen storage material.

[0073] The calcination comprises: heating the temperature to 400-800° C. at a heating rate of 5-20° C. / min, and then calcining for 3-6 hours.

[0074] Due to the introduction of nanoparticles for nucleation, compared with the conventional co-precipitation method, the present application needs to undergo a low-temperature aging after precipitation titration to facilitate the nucleation process of cerium-zirconium nanocrystals, prevent or inhibit rapid crystal growth, and avoid uneven particles.

[0075] The low-temperature, high-performance oxygen storage material comprises, by weight, 20-60% cerium oxide, 30-70% zirconium oxide, 3-15% metal-modified doping aid, and 0.1-3% nanoparticles.

[0076] It should be noted that the metal-modified doping aid is a product obtained by reacting a soluble salt of a metal-modified doping element and is contained in the low-temperature, high-performance oxygen storage material.

[0077] In the above step 101, in order to obtain solution A1, the present application also provides a preparation method. Specifically, the preparation of solution A1 includes: weighing a soluble cerium salt, a soluble zirconium salt and a soluble salt of a metal-modified doping element, dissolving the soluble cerium salt in hydrogen peroxide, dissolving the soluble zirconium salt in an aqueous nitric acid solution, and dissolving the soluble salt of the metal-modified doping element in hydrogen peroxide, and then mixing the above three solutions and stirring them evenly to obtain solution A1.

[0078] There are many options for soluble cerium salts, which can be selected according to actual needs. For example, as an example, the soluble cerium salts include one or more of cerium nitrate and cerium carbonate.

[0079] There are multiple options for soluble zirconium salts, which can be selected according to actual needs. For example, as an example, the soluble zirconium salts include one or more of zirconium nitrate and zirconium carbonate.

[0080] There are multiple options for the soluble salts of the metal-modified doping elements, which can be selected according to actual needs. For example, as an example, the soluble salts of the metal-modified doping elements include one or more of the nitrates and carbonates of the metal-modified doping elements.

[0081] There are multiple options for the metal-modified doping element, which can be selected according to actual needs. For example, as an example, the metal-modified doping element includes one or more of aluminum, rare earth elements, transition metal elements, alkali metal elements and alkaline earth metal elements.

[0082] The rare earth elements include one or more of lanthanum La, praseodymium Pr, neodymium Nd, and yttrium Y.

[0083] The transition metal elements include one or more of manganese Mn, copper Cu, iron Fe, and nickel Ni.

[0084] The alkaline earth metal elements include one or more of strontium Sr, calcium Ca, magnesium Mg, and barium Ba.

[0085] The oxygen storage performance of Ce-Zr oxygen storage materials comes from Ce 3+ and Ce 4+The reversible redox (oxygen storage and release) cycle is essentially determined by the unique electronic configuration of Ce. In fact, the oxygen storage and release processes of Ce-Zr oxygen storage materials proceed in a step-by-step manner, from surface to bulk. The filling of surface oxygen vacancies by gaseous oxygen occurs rapidly at room temperature, so the key steps determining the oxygen storage performance of Ce-Zr oxygen storage materials are the formation of oxygen vacancies and the migration and diffusion of oxygen species.

[0086] The effects of introducing metal modified doping elements are as follows:

[0087] 1) The introduced dopant ions will replace Ce in the lattice 4+ and Zr 4+ , due to the doping ions and Ce 4+ and Zr 4+ The difference in radius will cause the unit cell to shrink or expand, and this process will lead to the formation of structural defects related to cations;

[0088] 2) Since the valence of the dopant ions is low (usually +2 or +3), more oxygen vacancies will be generated in the lattice to maintain electrical neutrality;

[0089] 3) It can effectively stabilize the phase structure, reduce the sintering rate of the material and improve its thermal stability;

[0090] 4) It can increase the specific surface area of the material.

[0091] In the above step 101, in order to obtain solution A2, the present application also provides a preparation method. Specifically, the preparation of solution A2 includes: dissolving ammonium carbonate in water to obtain an ammonium carbonate solution; and mixing the ammonium carbonate solution with aqueous ammonia to obtain solution A2.

[0092] The water can be deionized water, distilled water, or purified water.

[0093] The molar ratio of the ammonium carbonate solution to the ammonia water is 0.5 to 2:1.

[0094] The molar concentrations of ammonium carbonate and ammonia water are both 1 to 5 mol / L.

[0095] In step 101, to obtain slurry A3, the present application further provides a modification method. Specifically, the nanoparticles are modified using a silane coupling agent to obtain slurry A3. The method comprises: adding the nanoparticles to a solvent, ultrasonically dispersing the nanoparticles, then adding the silane coupling agent, and then ultrasonically treating the nanoparticles (e.g., for 5 to 10 minutes) to obtain slurry A3. The amount of silane coupling agent added is 0.5-2% of the mass of the nanoparticles. Nanoparticles serve as nucleation sites for cerium-zirconium nanocrystals and are prone to agglomeration. Therefore, the purpose of the modification is to prevent nanoparticle agglomeration and promote dispersion, thereby facilitating the nucleation and growth of the oxygen storage material. The introduction of silicon can also improve the performance of the oxygen storage material.

[0096] The solvent is a solvent in which the volume ratio of ethanol to water is (2-8):1.

[0097] The ultrasonic dispersion time can be determined according to actual needs, mainly to ensure that the nanoparticles can be dispersed as evenly as possible in the solvent. For example, the ultrasonic dispersion time can be 3 to 5 minutes.

[0098] The nanoparticles include one or more of nano silicon dioxide and nano α-alumina powder.

[0099] Through extensive research, the applicant discovered that modified silica and α-alumina can produce the above-mentioned effects. However, experiments have shown that the corresponding modified γ-alumina cannot perform well. This may be because γ-alumina has poor thermal stability and undergoes phase transformation and sintering during the roasting process, resulting in structural collapse and degradation of the performance of the oxygen storage material.

[0100] The average particle size of the nanoparticles is 5 to 30 nm. If the particle size is less than 5 nm, the nanoparticles will aggregate and polymerize, and even modification will make it difficult to suppress the aggregation. If the particle size is greater than 30 nm, the nanoparticles themselves will be too large to be suitable as nucleation sites.

[0101] The silane coupling agent includes an amino-alkyl silane coupling agent. There are also various optional types of amino-alkyl silane coupling agents, which can be determined according to actual preparation needs. For example, as an example, the amino-alkyl silane coupling agent includes one or more of γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-ureapropyltriethoxysilane, and γ-(β-aminoethyl)aminopropyltrimethoxysilane.

[0102] The amino hydrocarbon-based silane coupling agent is used because it can be decomposed during the subsequent calcination process without introducing other impurities, and the gas generated by the decomposition can promote the formation of a porous structure.

[0103] The embodiment of the present application also provides a low-temperature, high-performance oxygen storage material, which is prepared using the preparation method of the low-temperature, high-performance oxygen storage material.

[0104] The embodiment of the present application also provides an automobile exhaust purification catalyst, which includes the low-temperature, high-performance oxygen storage material.

[0105] The present application is described in detail below through several examples and comparative examples.

[0106] Characterization methods

[0107] 1. Specific surface area characterization

[0108] The specific surface area of the catalysts of each example was characterized freshly (before aging) and after aging at 1000°C (after aging). The test method was as follows: the sample was first pretreated under vacuum at 300°C for 3 hours. Then, an adsorption test was performed at -196°C (liquid nitrogen) using high-purity N2 as the adsorption gas, and a desorption test was performed at 25°C. The specific surface area of the sample was calculated using the BET method (Autosorb SI fully automatic specific surface and pore size analyzer, Quantachrome). Specific surface area retention rate = specific surface area after aging / specific surface area before aging × 100%

[0109] 2. Characterization of low temperature reaction activity

[0110] The oxygen storage material powder after high-temperature aging and the Rh / Al2O3 powder loaded with Rh (0.5wt%) were physically mixed in a mortar in a mass ratio of 1:1, pressurized and crushed to obtain a pressed sheet catalyst with a diameter of 0.5mm to 1mm for automobile exhaust purification.

[0111] 20 mg of the resulting catalyst was weighed and its oxygen absorption and release were measured using a thermogravimetric analyzer. The oxygen absorption and release rate is the amount of oxygen absorbed and released per 20 mg of catalyst at 250°C (O₂-mg / cat-20 mg). The catalyst sample was placed in the sample cell of the thermogravimetric analyzer. A reducing atmosphere consisting of H₂ (4% by volume) and N₂ (96% by volume) and an oxidizing atmosphere consisting of O₂ (5% by volume) and N₂ (95% by volume) were alternately passed through the sample at a flow rate of 100 ml / min at 250°C for 20 minutes, for a total of 120 minutes (reduction-oxidation cycles repeated three times). The oxygen absorption and release rate was determined from the reversible weight change using the thermogravimetric analyzer. The value on the oxygen-releasing side (reducing side) was used for evaluation.

[0112] Sample description: Freshly prepared sample (before aging), sample after high temperature aging at 1000℃ (after aging).

[0113] Example 1:

[0114] A method for preparing a low-temperature, high-performance oxygen storage material comprises the following steps:

[0115] S01: Weigh cerium nitrate, zirconium carbonate, lanthanum nitrate, and yttrium nitrate, dissolve the cerium nitrate, lanthanum nitrate, and yttrium nitrate in aqueous hydrogen peroxide, dissolve zirconium carbonate in aqueous nitric acid, and mix and stir the aforementioned solutions to obtain solution A1;

[0116] S02: Weigh ammonium carbonate and dissolve it in deionized water to prepare a mixed solution A2 of ammonium carbonate and ammonia water in a molar ratio of 1:1;

[0117] S03: Weigh α-alumina powder with an average particle size of 10 nm and add it to an ethanol aqueous solution. Ultrasonic dispersion is performed for 5 minutes. Then, a silane coupling agent (γ-aminopropyltrimethoxysilane) with a mass of 1% based on the mass of the nanoparticles is added. Ultrasonic treatment is performed for another 10 minutes to obtain slurry A3.

[0118] S04: At 30°C, solution A1, solution A2, and slurry A3 were titrated and precipitated together. After the titration was completed, concentrated ammonia solution was added to the solution and stirred for 2 hours to obtain slurry B;

[0119] S05: transferring slurry B to a low temperature of 15°C for aging for 3 hours, and then transferring it to a high temperature of 98°C for aging for 2 hours, and then cooling the slurry to room temperature to obtain slurry C;

[0120] S06: heating slurry C to 70° C., adding concentrated aqueous ammonia, lauric acid, and polyvinyl alcohol to the slurry, stirring and reacting for 3 h, and then cooling the slurry to room temperature to obtain slurry D;

[0121] S07: The obtained slurry D is filtered and washed, and the filter cake obtained by filtration and washing is dried and calcined. The calcination conditions are 400-800°C, 6h, and a heating rate of 5-20°C / min to finally obtain a low-temperature and high-performance oxygen storage material.

[0122] In the final low-temperature, high-performance oxygen storage material, by weight, cerium oxide accounts for 40%, zirconium oxide accounts for 50%, the metal-modified doping additives are lanthanum oxide and yttrium oxide, each accounting for 4.5% by weight, and α-alumina accounts for 1%.

[0123] Example 2: Compared with Example 1, step S05 is to transfer slurry B to 25°C for low-temperature aging for 8 hours.

[0124] Specifically, a method for preparing a low-temperature, high-performance oxygen storage material comprises the following steps:

[0125] S01: Weigh cerium nitrate, zirconium carbonate, lanthanum nitrate, and yttrium nitrate, dissolve the cerium nitrate, lanthanum nitrate, and yttrium nitrate in aqueous hydrogen peroxide, dissolve zirconium carbonate in aqueous nitric acid, and mix and stir the aforementioned solutions to obtain solution A1;

[0126] S02: Weigh ammonium carbonate and dissolve it in deionized water to prepare a mixed solution A2 of ammonium carbonate and ammonia water in a molar ratio of 1:1;

[0127] S03: Weigh α-alumina powder with an average particle size of 10 nm and add it to an ethanol aqueous solution. Ultrasonic dispersion is performed for 5 minutes. Then, a silane coupling agent (γ-aminopropyltrimethoxysilane) with a mass of 1% based on the mass of the nanoparticles is added. Ultrasonic treatment is performed for another 10 minutes to obtain slurry A3.

[0128] S04: At 30°C, solution A1, solution A2, and slurry A3 were titrated and precipitated together. After the titration was completed, concentrated ammonia solution was added to the solution and stirred for 2 hours to obtain slurry B;

[0129] S05: transferring slurry B to a low temperature of 25°C for aging for 8 hours, and then transferring it to a high temperature of 98°C for aging for 2 hours, and then cooling the slurry to room temperature to obtain slurry C;

[0130] S06: heating slurry C to 70° C., adding concentrated aqueous ammonia, lauric acid, and polyvinyl alcohol to the slurry, stirring and reacting for 3 h, and then cooling the slurry to room temperature to obtain slurry D;

[0131] S07: The obtained slurry D is filtered and washed, and the filter cake obtained by filtration and washing is dried and calcined. The calcination conditions are 400-800°C, 6h, and a heating rate of 5-20°C / min to finally obtain a low-temperature and high-performance oxygen storage material.

[0132] In the final low-temperature, high-performance oxygen storage material, by weight, cerium oxide accounts for 40%, zirconium oxide accounts for 50%, the metal-modified doping additives are lanthanum oxide and yttrium oxide, each accounting for 4.5% by weight, and α-alumina accounts for 1%.

[0133] Example 3: Compared with Example 1, the nanoparticles are nano-silicon dioxide with an average particle size of 20 nm.

[0134] Specifically, a method for preparing a low-temperature, high-performance oxygen storage material comprises the following steps:

[0135] S01: Weigh cerium nitrate, zirconium carbonate, lanthanum nitrate, and yttrium nitrate, dissolve the cerium nitrate, lanthanum nitrate, and yttrium nitrate in aqueous hydrogen peroxide, dissolve zirconium carbonate in aqueous nitric acid, and mix and stir the aforementioned solutions to obtain solution A1;

[0136] S02: Weigh ammonium carbonate and dissolve it in deionized water to prepare a mixed solution A2 of ammonium carbonate and ammonia water in a molar ratio of 1:1;

[0137] S03: Nano-silica with an average particle size of 20 nm was weighed and added to an ethanol aqueous solution, and dispersed by ultrasonication for 5 minutes. Then, a silane coupling agent (γ-aminopropyltrimethoxysilane) was added at a mass of 1% of the mass of the nanoparticles, and ultrasonication was performed for another 10 minutes to obtain slurry A3;

[0138] S04: At 30°C, solution A1, solution A2, and slurry A3 were titrated and precipitated together. After the titration was completed, concentrated ammonia solution was added to the solution and stirred for 2 hours to obtain slurry B;

[0139] S05: transferring slurry B to a low temperature of 15°C for aging for 3 hours, and then transferring it to a high temperature of 98°C for aging for 2 hours, and then cooling the slurry to room temperature to obtain slurry C;

[0140] S06: heating slurry C to 70° C., adding concentrated aqueous ammonia, lauric acid, and polyvinyl alcohol to the slurry, stirring and reacting for 3 h, and then cooling the slurry to room temperature to obtain slurry D;

[0141] S07: The obtained slurry D is filtered and washed, and the filter cake obtained by filtration and washing is dried and calcined. The calcination conditions are 400-800°C, 6h, and a heating rate of 5-20°C / min to finally obtain a low-temperature and high-performance oxygen storage material.

[0142] In the final low-temperature, high-performance oxygen storage material, by weight, cerium oxide accounts for 40%, zirconium oxide accounts for 50%, the metal-modified doping additives are lanthanum oxide and yttrium oxide, each accounting for 4.5% by weight, and nano-silicon dioxide accounts for 1%.

[0143] Example 4: Compared with Example 1, the average particle size of the α-alumina powder is 30 nm, and the nanoparticles are pretreated and modified: α-alumina powder of a certain particle size is weighed and added to an ethanol aqueous solution, and dispersed by ultrasonication for 5 minutes, and then γ-aminopropyltriethoxysilane with a mass of 0.5% of the mass of the nanoparticles is added, and then ultrasonicated for 10 minutes to obtain slurry A3.

[0144] Specifically, a method for preparing a low-temperature, high-performance oxygen storage material comprises the following steps:

[0145] S01: Weigh cerium nitrate, zirconium carbonate, lanthanum nitrate, and yttrium nitrate, dissolve the cerium nitrate, lanthanum nitrate, and yttrium nitrate in aqueous hydrogen peroxide, dissolve zirconium carbonate in aqueous nitric acid, and mix and stir the aforementioned solutions to obtain solution A1;

[0146] S02: Weigh ammonium carbonate and dissolve it in deionized water to prepare a mixed solution A2 of ammonium carbonate and ammonia water in a molar ratio of 1:1;

[0147] S03: Weigh α-alumina powder with an average particle size of 30 nm and add it to an ethanol aqueous solution. Ultrasonic dispersion is performed for 5 minutes. Then, a silane coupling agent (γ-aminopropyltrimethoxysilane) with a mass of 0.5% based on the mass of the nanoparticles is added. Ultrasonic treatment is performed for another 10 minutes to obtain slurry A3.

[0148] S04: At 30°C, solution A1, solution A2, and slurry A3 were titrated and precipitated together. After the titration was completed, concentrated ammonia solution was added to the solution and stirred for 2 hours to obtain slurry B;

[0149] S05: transferring slurry B to a low temperature of 15°C for aging for 3 hours, and then transferring it to a high temperature of 98°C for aging for 2 hours, and then cooling the slurry to room temperature to obtain slurry C;

[0150] S06: heating slurry C to 70° C., adding concentrated aqueous ammonia, lauric acid, and polyvinyl alcohol to the slurry, stirring and reacting for 3 h, and then cooling the slurry to room temperature to obtain slurry D;

[0151] S07: The obtained slurry D is filtered and washed, and the filter cake obtained by filtration and washing is dried and calcined. The calcination conditions are 400-800°C, 6h, and a heating rate of 5-20°C / min to finally obtain a low-temperature and high-performance oxygen storage material.

[0152] In the final low-temperature, high-performance oxygen storage material, by weight, cerium oxide accounts for 40%, zirconium oxide accounts for 50%, the metal-modified doping additives are lanthanum oxide and yttrium oxide, each accounting for 4.5% by weight, and α-alumina accounts for 1%.

[0153] Comparative Example 1: Compared with Example 1, no pre-treated modified α-alumina powder was added.

[0154] Specifically, a method for preparing a low-temperature, high-performance oxygen storage material comprises the following steps:

[0155] S01: Weigh cerium nitrate, zirconium carbonate, lanthanum nitrate, and yttrium nitrate, dissolve the cerium nitrate, lanthanum nitrate, and yttrium nitrate in aqueous hydrogen peroxide, dissolve zirconium carbonate in aqueous nitric acid, and mix and stir the aforementioned solutions to obtain solution A1;

[0156] S02: Weigh ammonium carbonate and dissolve it in deionized water to prepare a mixed solution A2 of ammonium carbonate and ammonia water in a molar ratio of 1:1;

[0157] S03: At 30°C, solution A1 and solution A2 were titrated and precipitated together. After the titration was completed, concentrated ammonia solution was added to the solution and stirred for 2 hours to obtain slurry B;

[0158] S04: transferring slurry B to a low temperature of 15°C for aging for 3 hours, then transferring it to a high temperature of 98°C for aging for 2 hours, and then cooling the slurry to room temperature to obtain slurry C;

[0159] S05: heating slurry C to 70° C., adding concentrated ammonia, lauric acid, and polyvinyl alcohol to the slurry, stirring and reacting for 3 h, and then cooling the slurry to room temperature to obtain slurry D;

[0160] S06: The obtained slurry D is filtered and washed, and the filter cake obtained by filtration and washing is dried and calcined. The calcination conditions are 400-800°C, 6h, and a heating rate of 5-20°C / min to finally obtain a low-temperature and high-performance oxygen storage material.

[0161] In the final low-temperature, high-performance oxygen storage material, by weight, cerium oxide accounts for 40%, zirconium oxide accounts for 50%, and the metal-modified doping additives are lanthanum oxide and yttrium oxide, each accounting for 5% by weight.

[0162] Comparative Example 2: Compared with Example 1, the added α-alumina powder was not pre-treated and modified in step S03.

[0163] Specifically, a method for preparing a low-temperature, high-performance oxygen storage material comprises the following steps:

[0164] S01: Weigh cerium nitrate, zirconium carbonate, lanthanum nitrate, and yttrium nitrate, dissolve the cerium nitrate, lanthanum nitrate, and yttrium nitrate in aqueous hydrogen peroxide, dissolve zirconium carbonate in aqueous nitric acid, and mix and stir the aforementioned solutions to obtain solution A1;

[0165] S02: Weigh ammonium carbonate and dissolve it in deionized water to prepare a mixed solution A2 of ammonium carbonate and ammonia water in a molar ratio of 1:1;

[0166] S03: Weigh α-alumina powder with an average particle size of 10 nm and add it to an ethanol aqueous solution, and disperse it by ultrasonication for 5 minutes to obtain slurry A3;

[0167] S04: At 30°C, solution A1, solution A2, and slurry A3 were titrated and precipitated together. After the titration was completed, concentrated ammonia solution was added to the solution and stirred for 2 hours to obtain slurry B;

[0168] S05: transferring slurry B to a low temperature of 15°C for aging for 3 hours, and then transferring it to a high temperature of 98°C for aging for 2 hours, and then cooling the slurry to room temperature to obtain slurry C;

[0169] S06: heating slurry C to 70° C., adding concentrated aqueous ammonia, lauric acid, and polyvinyl alcohol to the slurry, stirring and reacting for 3 h, and then cooling the slurry to room temperature to obtain slurry D;

[0170] S07: The obtained slurry D is filtered and washed, and the filter cake obtained by filtration and washing is dried and calcined. The calcination conditions are 400-800°C, 6h, and a heating rate of 5-20°C / min to finally obtain a low-temperature and high-performance oxygen storage material.

[0171] In the final low-temperature, high-performance oxygen storage material, by weight, cerium oxide accounts for 40%, zirconium oxide accounts for 50%, the metal-modified doping additives are lanthanum oxide and yttrium oxide, each accounting for 4.5% by weight, and α-alumina accounts for 1%.

[0172] Comparative Example 3: Compared with Example 1, in step S05, slurry B is directly transferred to 98°C for high-temperature aging for 5 hours, and then the slurry is cooled to room temperature to obtain slurry C (without low-temperature aging).

[0173] Specifically, a method for preparing a low-temperature, high-performance oxygen storage material comprises the following steps:

[0174] S01: Weigh cerium nitrate, zirconium carbonate, lanthanum nitrate, and yttrium nitrate, dissolve the cerium nitrate, lanthanum nitrate, and yttrium nitrate in aqueous hydrogen peroxide, dissolve zirconium carbonate in aqueous nitric acid, and mix and stir the aforementioned solutions to obtain solution A1;

[0175] S02: Weigh ammonium carbonate and dissolve it in deionized water to prepare a mixed solution A2 of ammonium carbonate and ammonia water in a molar ratio of 1:1;

[0176] S03: Weigh α-alumina powder with an average particle size of 10 nm and add it to an ethanol aqueous solution. Ultrasonic dispersion is performed for 5 minutes. Then, a silane coupling agent (γ-aminopropyltrimethoxysilane) with a mass of 1% based on the mass of the nanoparticles is added. Ultrasonic treatment is performed for another 10 minutes to obtain slurry A3.

[0177] S04: At 30°C, solution A1, solution A2, and slurry A3 were titrated and precipitated together. After the titration was completed, concentrated ammonia solution was added to the solution and stirred for 2 hours to obtain slurry B;

[0178] S05: transferring slurry B to 98°C for high temperature aging for 5 hours, and then cooling the slurry to room temperature to obtain slurry C;

[0179] S06: heating slurry C to 70° C., adding concentrated aqueous ammonia, lauric acid, and polyvinyl alcohol to the slurry, stirring and reacting for 3 h, and then cooling the slurry to room temperature to obtain slurry D;

[0180] S07: The obtained slurry D is filtered and washed, and the filter cake obtained by filtration and washing is dried and calcined. The calcination conditions are 400-800°C, 6h, and a heating rate of 5-20°C / min to finally obtain a low-temperature and high-performance oxygen storage material.

[0181] In the final low-temperature, high-performance oxygen storage material, by weight, cerium oxide accounts for 40%, zirconium oxide accounts for 50%, the metal-modified doping additives are lanthanum oxide and yttrium oxide, each accounting for 4.5% by weight, and α-alumina accounts for 1%.

[0182] Comparative Example 4: Compared with Example 1, pretreated and modified γ-alumina powder was added.

[0183] Specifically, a method for preparing a low-temperature, high-performance oxygen storage material comprises the following steps:

[0184] S01: Weigh cerium nitrate, zirconium carbonate, lanthanum nitrate, and yttrium nitrate, dissolve the cerium nitrate, lanthanum nitrate, and yttrium nitrate in aqueous hydrogen peroxide, dissolve zirconium carbonate in aqueous nitric acid, and mix and stir the aforementioned solutions to obtain solution A1;

[0185] S02: Weigh ammonium carbonate and dissolve it in deionized water to prepare a mixed solution A2 of ammonium carbonate and ammonia water in a molar ratio of 1:1;

[0186] S03: γ-alumina powder with an average particle size of 10 nm was weighed and added to an ethanol aqueous solution, and dispersed by ultrasonication for 5 minutes. Then, a silane coupling agent (γ-aminopropyltrimethoxysilane) was added at a mass of 1% of the mass of the nanoparticles, and ultrasonication was performed for another 10 minutes to obtain slurry A3;

[0187] S04: At 30°C, solution A1, solution A2, and slurry A3 were titrated and precipitated together. After the titration was completed, concentrated ammonia solution was added to the solution and stirred for 2 hours to obtain slurry B;

[0188] S05: transferring slurry B to a low temperature of 15°C for aging for 3 hours, and then transferring it to a high temperature of 98°C for aging for 2 hours, and then cooling the slurry to room temperature to obtain slurry C;

[0189] S06: heating slurry C to 70° C., adding concentrated aqueous ammonia, lauric acid, and polyvinyl alcohol to the slurry, stirring and reacting for 3 h, and then cooling the slurry to room temperature to obtain slurry D;

[0190] S07: The obtained slurry D is filtered and washed, and the filter cake obtained by filtration and washing is dried and calcined. The calcination conditions are 400-800°C, 6h, and a heating rate of 5-20°C / min to finally obtain a low-temperature and high-performance oxygen storage material.

[0191] In the final low-temperature, high-performance oxygen storage material, by weight, cerium oxide accounts for 40%, zirconium oxide accounts for 50%, the metal-modified doping additives are lanthanum oxide and yttrium oxide, each accounting for 4.5% by weight, and γ-alumina accounts for 1%.

[0192]

[0193]

[0194] From the test data in the table, it can be seen that the oxygen storage material prepared in the examples has a very high specific surface area, high temperature aging resistance and excellent reaction activity at low temperatures.

[0195] It can be seen from the test data of Example 1 and Comparative Example 1 that without adding pretreated modified α-alumina powder, the specific surface area, high temperature aging resistance and excellent reaction activity at low temperature of the oxygen storage material will all decrease, and the decrease will be large.

[0196] The test data from Example 1 and Comparative Example 2 demonstrate that pretreatment and modification of nanoparticles are crucial for effectively increasing the specific surface area and reactivity after aging. Nanoparticles, which serve as nucleation sites for cerium-zirconium nanocrystals, are prone to agglomeration. Therefore, the purpose of modification is to prevent nanoparticle agglomeration and promote dispersion, thereby facilitating the nucleation and growth of the oxygen storage material. The introduction of silicon also enhances the performance of the oxygen storage material.

[0197] The test data from Example 1 and Comparative Example 3 demonstrate that low-temperature aging is crucial for effectively increasing the specific surface area and reactivity after aging. Compared to the room-temperature aging method used in the prior art, the present invention undergoes both low-temperature and high-temperature aging before cooling to room temperature. Choosing low-temperature aging first reduces nucleation in the cerium-zirconium compound itself, prioritizing nucleation on the modified nanoparticles. Low-temperature aging for a period of time allows uniform nucleation and growth of all grains in the system.

[0198] It can be seen from the test data of Example 1 and Comparative Example 4 that if the nanoparticles are replaced with γ-alumina powder, although the fresh sample of the oxygen storage material can obtain a higher surface area, its aged specific surface area will decrease, which may be related to the poor thermal stability of γ-alumina. In addition, it was unexpectedly found that γ-alumina also significantly reduces the low-temperature reaction activity, which may be related to the different crystal planes exposed by γ-alumina and α-alumina when inducing the growth of cerium-zirconium nanocrystals.

[0199] In the description of this application, it should be noted that the terms "upper" and "lower" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application. Unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be internal communication between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0200] It should be noted that, in this application, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprising a ..." does not exclude the presence of other identical elements in the process, method, article or device comprising the element.

[0201] The foregoing is merely a list of specific embodiments of the present application, intended to enable those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but is intended to conform to the broadest scope consistent with the principles and novel features of the present application.

Claims

1. A method for preparing a low-temperature, high-performance oxygen storage material, characterized in that: It includes the following steps: Prepare a solution A1, wherein the solution A1 contains cerium, zirconium, and a metal-modified doping element for modifying the cerium and zirconium; preparing a solution A2, wherein the solution A2 contains ammonium carbonate and aqueous ammonia; The nanoparticles are modified using a silane coupling agent to obtain slurry A3; The solution A1, solution A2 and slurry A3 are titrated and precipitated together. After the titration is completed, concentrated ammonia water is added and stirred to obtain slurry B; The slurry B is subjected to low-temperature aging treatment and high-temperature aging treatment in sequence to obtain slurry C; After heating the slurry C to a set temperature, adding concentrated ammonia water and a surfactant to the slurry C, stirring and reacting, to obtain slurry D; The slurry D is filtered and washed, and the filter cake obtained by the filtration and washing is dried and calcined to obtain a low-temperature and high-performance oxygen storage material; The nanoparticles include one or more of nano silicon dioxide and nano α-alumina powder; The silane coupling agent includes an amino hydrocarbon-based silane coupling agent.

2. The method for preparing the low-temperature, high-performance oxygen storage material according to claim 1, wherein: In the low-temperature, high-performance oxygen storage material, by weight, cerium oxide accounts for 20-60%, zirconium oxide accounts for 30-70%, metal-modified doping additive accounts for 3-15%, and nanoparticles account for 0.1-3%.

3. The method for preparing the low-temperature, high-performance oxygen storage material according to claim 1, wherein: Prepare solution A1, specifically comprising: A soluble cerium salt is dissolved in hydrogen peroxide, a soluble zirconium salt is dissolved in a nitric acid aqueous solution, and a soluble salt of a metal-modified doping element is dissolved in hydrogen peroxide, and then the mixture is mixed and stirred uniformly to obtain a solution A1.

4. The method for preparing a low-temperature, high-performance oxygen storage material according to claim 3, wherein: The soluble cerium salt includes one or more of cerium nitrate and cerium carbonate; Soluble zirconium salts include one or more of zirconium nitrate and zirconium carbonate; The soluble salt of the metal-modified doping element includes one or more of the nitrate and carbonate of the metal-modified doping element.

5. The method for preparing the low-temperature, high-performance oxygen storage material according to claim 1, wherein: The metal modified doping element includes one or more of aluminum, rare earth elements, transition metal elements, alkali metal elements and alkaline earth metal elements.

6. The method for preparing a low-temperature, high-performance oxygen storage material according to claim 1, wherein: Prepare solution A2, specifically comprising: dissolving ammonium carbonate in water to obtain an ammonium carbonate solution; The ammonium carbonate solution was mixed with aqueous ammonia to obtain solution A2.

7. The method for preparing a low-temperature, high-performance oxygen storage material according to claim 6, wherein: The molar ratio of the ammonium carbonate solution to the ammonia water is 0.5-2:

1.

8. The method for preparing a low-temperature, high-performance oxygen storage material according to claim 1, wherein: The nanoparticles are modified using a silane coupling agent to obtain slurry A3, specifically comprising: The nanoparticles are added to a solvent and dispersed by ultrasonication, and then a silane coupling agent is added and ultrasonicated to obtain slurry A3. The amount of the silane coupling agent added is 0.5-2% of the mass of the nanoparticles.

9. The method for preparing a low-temperature, high-performance oxygen storage material according to claim 1, wherein: The average particle size of the nanoparticles is 5-30 nm.

10. The method for preparing a low-temperature, high-performance oxygen storage material according to claim 9, wherein: The amino hydrocarbon-based silane coupling agent includes one or more of γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-ureapropyltriethoxysilane, and γ-(β-aminoethyl)aminopropyltrimethoxysilane.

11. The method for preparing a low-temperature, high-performance oxygen storage material according to claim 1, wherein: The low-temperature aging treatment includes: low-temperature aging at 15-25° C. for 3-8 hours.

12. The method for preparing a low-temperature, high-performance oxygen storage material according to claim 1, wherein: The high-temperature aging treatment includes: high-temperature aging at 90-98° C. for 2-5 hours.

13. The method for preparing a low-temperature, high-performance oxygen storage material according to claim 1, wherein: The set temperature is 50-70°C.

14. The method for preparing a low-temperature, high-performance oxygen storage material according to claim 1, wherein: The surfactant is a mixture of fatty acid and polyvinyl alcohol, or a mixture of carboxylic acid ester and polyvinyl alcohol.

15. The method for preparing a low-temperature, high-performance oxygen storage material according to claim 14, wherein: The fatty acid includes one or more of lauric acid, palmitic acid, stearic acid and oleic acid; The carboxylic acid ester includes one or more of Tween 20, Tween 60 and Tween 80.

16. The method for preparing a low-temperature, high-performance oxygen storage material according to claim 1, wherein: The calcination comprises: heating the temperature to 400-800° C. at a heating rate of 5-20° C. / min, and then calcining for 3-6 hours.

17. A low-temperature, high-performance oxygen storage material, characterized by: It is prepared by the preparation method of the low-temperature and high-performance oxygen storage material according to any one of claims 1 to 16.

18. An automobile exhaust purification catalyst, characterized by: It includes the low-temperature, high-performance oxygen storage material as claimed in claim 17.

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