Preparation method of carrier type nano zirconium oxide composite material with large specific surface area

Abstract

The application relates to a preparation method of a carrier type nano zirconium oxide composite material with a large specific surface area, and belongs to the technical field of carrier materials. A uniform hydroxide precursor is formed through Ce-Y double-doped coprecipitation reaction, a skeleton foundation is laid for subsequent pore structure construction, and pore structure defects caused by a single group analysis are avoided; a glucose green pore-forming agent is used to form a mesoporous structure in a calcination stage, water is removed through a n-butanol azeotropic distillation process, particle hard agglomeration is effectively inhibited through butoxy group surface hydroxyl group replacement, pore blockage is prevented, a zirconium-based MOF is in-situ grown on the surface of the zirconium oxide base through a hydrothermal synthesis method, a multistage mesoporous structure system is formed, and the specific surface area of the carrier type nano zirconium oxide composite material is improved through cooperation of the three, a large number of accessible surface active sites are provided for adsorption, catalysis and other applications, and the adsorption performance and active component loading capacity of the material are significantly enhanced.

Description

Technical Field

[0001] This invention belongs to the field of carrier material technology and relates to a method for preparing a carrier-type nano-zirconia composite material with a large specific surface area. Background Technology

[0002] Nano-zirconia (ZrO2), as a novel inorganic non-metallic material with excellent physicochemical properties, has demonstrated irreplaceable application value in multiple high-end fields such as catalysis, biomedicine, aerospace, energy and environmental protection, and precision ceramics due to its good thermal stability, chemical inertness, high hardness, excellent ionic conductivity, and phase transformation toughening characteristics. Among them, carrier-based nano-zirconia composites have become a research hotspot in materials science in recent years because they can rely on the structural advantages of the carrier to solve problems such as easy agglomeration, poor dispersibility, and difficult molding of pure nano-zirconia, while also endowing the material with synergistic reinforcing properties. Specific surface area is one of the core performance indicators of carrier-based nano-zirconia composites. A large specific surface area means that the material has more surface active sites, better adsorption performance and loading capacity, which can significantly optimize the mass transfer efficiency in catalytic reactions, the osseointegration ability in the biomedical field, and the ion conduction efficiency in the energy field. This is crucial for expanding the application scenarios and improving the performance of the material.

[0003] Chinese invention patent application CN101890377A discloses a zirconium oxide-alumina composite oxide support and its preparation method. This support uses zirconium hydroxide-alumina hydroxide gel prepared by the supersol-colloid method as raw material. Because this gel contains surfactants and hydrocarbon components, after molding and calcination, the polymerized zirconium hydroxide and alumina hydroxide, after dehydration, form nano-zirconia and alumina particles that still possess a rod-like basic structure and are randomly stacked into a framework structure. This support has large pore volume, large pore size, high porosity, and relatively large external pore openings with good pore penetration, which is beneficial for increasing the deposition of impurities and extending the catalyst's operating cycle.

[0004] The carrier in the above scheme relies solely on the disordered stacking of rod-shaped particles to form a framework structure. The pore type is singular, mainly macropores, and lacks mesopores. In the application scenario of deep degradation of organic pollutants, it exhibits the problem of uneven mass transfer efficiency. It is prone to situations where reactants cannot quickly contact the internal active sites, and small molecules can easily penetrate the pores without effective adsorption, resulting in low overall reaction efficiency. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing a carrier-type nano-zirconia composite material with a large specific surface area. By using a synergistic process of double doping co-precipitation, pore-forming agent-assisted azeotropic reaction, and MOF in-situ composite, the crystal phase and hierarchical pore structure are controlled, thereby improving the stability and specific surface area of ​​the carrier-type nano-zirconia composite material.

[0006] The objective of this invention can be achieved through the following technical solutions: A method for preparing a carrier-type nano-zirconia composite material with a large specific surface area includes the following steps: Step 1: Using zirconium nitrate pentahydrate as the zirconium source and ammonia as the hydroxide ion donor, cerium salt and yttrium salt undergo a co-precipitation reaction in an alkaline environment to obtain a precursor solution.

[0007] Step 2: Fully mature the precursor solution, add a pore-forming agent, remove water by azeotropic distillation to obtain precursor powder; calcine the precursor powder to obtain tetragonal phase nano-zirconia composite powder.

[0008] Step 3: The tetragonal phase nano-zirconia composite powder is ultrasonically dispersed, and then a zirconium-based MOF is generated in situ on the surface of the tetragonal phase nano-zirconia composite powder by hydrothermal synthesis, resulting in a carrier-type nano-zirconia composite material with a large specific surface area.

[0009] Furthermore, the specific preparation process of the precursor solution is as follows: Zirconium nitrate pentahydrate, cerium salt, yttrium salt, and deionized water were added to a reaction vessel and stirred until homogeneous. A 25 wt% hydrogen peroxide solution was then added and stirred for 50-60 minutes to obtain a mixed solution. The mixed solution was then added dropwise to a 1.0-1.1 mol / L ammonia solution, maintaining the pH at 10 during the addition process to obtain the precursor solution.

[0010] The core function of hydrogen peroxide solution is to remove Ce 3+ Partially oxidized to Ce 4+ First, it introduces oxygen vacancies to enhance the reactivity of subsequent materials; second, it stabilizes the metal ion system to avoid uneven precipitation caused by excessively high local concentrations. Maintaining a pH of 10 is a key control condition to ensure the stability of Zr. 4+ Ce 3+ / Ce 4+ Y 3+ Simultaneous co-precipitation occurs to form a uniform hydroxide precursor, avoiding premature precipitation of a single component that would lead to uneven doping and thus affect the stability of the tetragonal phase.

[0011] Furthermore, the ratio of zirconium nitrate pentahydrate, cerium salt, yttrium salt, deionized water, hydrogen peroxide solution, and ammonia water is 11.592-17.592g: 1.303-1.703g: 0.24-0.32g: 240-300mL: 9-15mL: 60-80mL.

[0012] Zirconium nitrate pentahydrate was used as the main zirconium source, and its dosage range ensured both reaction efficiency and avoided agglomeration due to excessive concentration. The dosage of cerium salt and yttrium salt achieved the best effect of synergistic stabilization of the tetragonal phase through dual doping, and the dosage of hydrogen peroxide solution was sufficient to oxidize Ce.3+ And stabilize the system.

[0013] Furthermore, the cerium salt is either cerium nitrate hexahydrate or cerium chloride. Both have excellent water solubility and can rapidly dissociate to release Ce. 3+ It exhibits good synergistic oxidation with hydrogen peroxide, and cerium nitrate hexahydrate leaves no harmful anion residues. After calcination, nitrate ions are completely decomposed, making it the preferred choice.

[0014] Furthermore, the yttrium salt is either yttrium nitrate hexahydrate or yttrium chloride. Both have excellent water solubility, and Y... 3+ Ionic radius and Zr 4+ Proximity allows for effective embedding into the zirconium oxide lattice, synergistically with Ce. 3+ Stable tetragonal phase.

[0015] Furthermore, the specific preparation process of the precursor powder is as follows: The precursor solution was stirred at 20-25℃ and 300-500 r / min for 60-70 min. After the reaction was completed, the mixture was filtered, and the precipitate was washed successively with deionized water and ethanol. The washed precipitate, n-butanol and glucose were then added to a reaction vessel and distilled at 98-100℃ for 30-40 min to obtain a first distillate. The first distillate was then distilled at 123℃ for 60-70 min to obtain the precursor powder.

[0016] Room temperature curing avoids rapid particle growth caused by excessively high temperatures. An appropriate stirring rate ensures uniform precipitation without damaging particle integrity. Butanol removes water through azeotropic distillation, and the butoxy group replaces the surface hydroxyl group to form steric hindrance, further inhibiting hard agglomeration. Glucose, as a green and biodegradable pore-forming agent, is uniformly dispersed in the system and decomposes during subsequent calcination to form a mesoporous structure, ensuring uniform pore formation without affecting particle dispersibility.

[0017] Furthermore, the ratio of precursor solution, n-butanol, and glucose is 310-400 mL: 500-600 mL: 5-7 g.

[0018] Furthermore, the specific preparation process of the tetragonal phase nano-zirconia composite powder is as follows: The precursor powder was placed in a muffle furnace and heated to 400-420℃ at a heating rate of 5℃ / min, and calcined for 1-2 hours. Then, it was heated to 600-640℃ at a heating rate of 5℃ / min and calcined for 3-4 hours to obtain stable tetragonal phase nano-zirconia composite powder.

[0019] The first stage of low-temperature calcination mainly decomposes glucose pore-forming agent and residual n-butanol, avoiding the collapse of the pore structure caused by the violent volatilization of organic matter at high temperature. The second stage of high-temperature calcination completely crystallizes the hydroxide precursor to form zirconium oxide. At the same time, Ce-Y dual doping synergistically stabilizes the tetragonal phase, preventing it from transforming into the monoclinic phase during cooling. The constant heating rate can reduce the temperature gradient between grains, avoid particle breakage caused by thermal stress, ensure sufficient reaction and prevent excessive sintering and growth of grains.

[0020] Furthermore, the specific preparation process of the carrier-type nano-zirconia composite material with a large specific surface area is as follows: Tetragonal phase nano-zirconia composite powder, zirconium chloride, substituted phthalic acid compounds and acetone were added to a reaction vessel and ultrasonically dispersed for 30-40 min. The mixture was then heated for 24-26 h under sealed conditions and at 100-120 °C. After the reaction was completed, the mixture was centrifuged, washed and dried to obtain a carrier-type nano-zirconia composite material with a large specific surface area.

[0021] Ultrasonic dispersion allows tetragonal zirconia composite powder to be uniformly dispersed in acetone, avoiding agglomeration that leads to uneven MOF growth. Zirconium chloride is used as a supplementary Zr source, replacing phthalic acid compounds as organic ligands. Under sealed heating conditions, zirconium-based MOFs are grown in situ on the zirconia surface through coordination reactions. The porous structure of the MOFs forms a hierarchical porous system with the zirconia substrate, significantly increasing the specific surface area.

[0022] Furthermore, the ratio of tetragonal phase nano-zirconia composite powder, zirconium chloride, substituted phthalic acid compounds and acetone is 3.8-4.2g: 9-13g: 8.6-10.6g: 3-4L.

[0023] Furthermore, the substituted phthalic acid compounds are either nitroterephthalic acid or terephthalic acid.

[0024] The beneficial effects of this invention are: 1. This invention first forms a homogeneous hydroxide precursor through a Ce-Y dual-doping co-precipitation reaction, laying a regular framework for the subsequent construction of pore structures and avoiding pore structure defects caused by single-group analysis. Then, a glucose green pore-forming agent is decomposed during the calcination stage to form a mesoporous structure. Moisture is removed by n-butanol azeotropic distillation. At the same time, the hard agglomeration of particles is effectively inhibited by butoxy substitution of surface hydroxyl groups to prevent pore blockage. Finally, zirconium-based MOFs are grown in situ on the surface of a zirconium oxide substrate through hydrothermal synthesis to form a multi-level mesoporous structure system. The three components synergistically improve the specific surface area of ​​the carrier-type nano-zirconia composite material, providing a large number of accessible surface active sites for adsorption, catalysis and other applications. This significantly enhances the adsorption performance and active component loading capacity of the material. At the same time, the multi-level pores accelerate the contact between reactants and active sites and the desorption of products, effectively solving the technical problems of uneven mass transfer efficiency and low reaction efficiency of traditional carriers.

[0025] 2. In this invention, Ce 3+ / Ce 4+ With Y 3+ Double doping forms a solid solution, Y 3+ ionic radius and Zr 4+ Radius matching and lattice embedding, along with Ce elements, suppress the tetragonal-to-monoclinic phase transition, avoiding the collapse of the pore structure caused by lattice volume changes during the phase transition. This results in a crystalline stable tetragonal zirconium oxide substrate. Simultaneously, azeotropic distillation replaces surface hydroxyl groups with butoxy groups, and ultrasonic dispersion breaks up agglomerated particles, synergistically improving dispersion uniformity. This provides a smooth interface foundation for the uniform growth of zirconium-based MOFs on the substrate surface and prevents particle agglomeration from obscuring active sites during use, ensuring continuous and effective exposure of active sites. This allows the adsorption, catalytic, and other properties of the material to remain stable during long-term use, solving the problems of unstable crystalline phase, easy agglomeration, and rapid performance degradation of traditional zirconium oxide supports.

[0026] 3. This invention selects glucose as a biodegradable pore-forming agent, which can be completely decomposed into water and carbon dioxide during calcination without any impurity residue. Compared with the traditional method of using surfactants to form pores, which is prone to producing carbides and inorganic salt residues, the preparation process is more environmentally friendly and avoids impurities covering active sites and affecting material performance. In addition, nitro terephthalic acid or terephthalic acid can be flexibly selected in the MOF preparation process. The strong electron-withdrawing properties of nitro groups can regulate the electronic structure of MOF, optimize the catalytic and adsorption activities of the material, and adapt to different types of catalytic reactions or adsorption requirements. The prepared composite material combines the excellent thermal stability and chemical inertness of nano-zirconia with the porous structure flexibility of zirconium-based MOFs. It can be used as a catalytic carrier, suitable for catalytic fields such as organic pollutant degradation and gas catalytic conversion, and can also be used as a high-efficiency adsorption material in environmental protection fields such as water purification and gas separation. Its application scenarios are wide-ranging. Detailed Implementation

[0027] To further illustrate the technical means and effects of the present invention in achieving the intended purpose, the following detailed description of the specific implementation methods, features and effects of the present invention, in conjunction with preferred embodiments, is provided below.

[0028] Example 1: This example provides a method for preparing a carrier-type nano-zirconia composite material with a large specific surface area, including the following steps: S1: Add 14.592g zirconium nitrate pentahydrate, 1.503g cerium nitrate hexahydrate, 0.28g yttrium nitrate hexahydrate and 270mL deionized water to a reaction vessel and stir until homogeneous. Add 12mL of 25wt% hydrogen peroxide solution and stir for 55min. Add the resulting mixed solution dropwise to 70mL of 1.05mol / L ammonia water while maintaining the pH at 10 during the dropwise addition to obtain the precursor solution.

[0029] Zirconium nitrate pentahydrate, cerium nitrate hexahydrate, and yttrium nitrate hexahydrate are dissolved in deionized water to form a mixed metal salt solution. Ammonia provides hydroxide ions to co-precipitate the solution. The pH is maintained at 10 to ensure the formation of a pure tetragonal precursor. Ce and Y doping are simultaneously incorporated into the precursor structure, laying the foundation for the subsequent product's crystal phase stability and performance optimization.

[0030] S2: Stir 355 mL of the precursor solution at 22 °C and 400 r / min for 65 min. After the reaction, filter under vacuum, collect the precipitate, wash the precipitate 4 times with deionized water, and then wash it 2 times with ethanol. Add the washed precipitate, 550 mL of n-butanol, and 6 g of glucose to the reaction vessel, and distill at 99 °C for 35 min to obtain the first distillate. Distill the first distillate at 123 °C for 65 min to remove excess n-butanol and obtain the precursor powder.

[0031] The precursor solution was fully matured at room temperature and under medium-speed stirring to ensure complete precipitation reaction and uniform particle growth. After washing with deionized water and ethanol to remove impurities such as nitrate and ammonium, n-butanol was added and water was removed by azeotropic distillation. Glucose was used as a pore-forming agent and uniformly dispersed in the system to finally obtain a precursor powder that has both dispersibility and pore-forming properties.

[0032] S3: The precursor powder was placed in a muffle furnace and heated to 410°C at a heating rate of 5°C / min, and calcined for 1.5 h. Then, it was heated to 620°C at a heating rate of 5°C / min and calcined for 3.5 h to obtain stable tetragonal phase nano-zirconia composite powder.

[0033] Gradual calcination at a constant heating rate decomposes glucose to form a mesoporous structure and removes residual organic matter in the low-temperature stage, while the high-temperature stage allows the precursor to fully crystallize. Ce and Y dual doping synergistically stabilize the tetragonal phase structure, preventing grain sintering and agglomeration, ultimately obtaining a stable and porous tetragonal phase nano-zirconia composite powder.

[0034] S4: 4.0g of tetragonal phase nano-zirconia composite powder, 11g of zirconium chloride, 9.6g of nitroterephthalic acid and 3.5L of acetone were added to a reaction vessel and ultrasonically dispersed for 35min. The mixture was heated at 110℃ for 25h under sealed conditions. After the reaction was completed, the mixture was centrifuged and the precipitate was washed four times with acetone and methanol in sequence. The precipitate was dried at 52℃ for 7h to obtain a carrier-type nano-zirconia composite material with a large specific surface area.

[0035] Tetragonal phase nano-zirconia composite powder was ultrasonically dispersed and uniformly mixed with zirconium chloride and nitroterephthalic acid in acetone. Under sealed heating conditions, zirconium chloride provided the Zr source, and nitroterephthalic acid, as an organic ligand, constructed an organic-inorganic composite structure in situ on the surface of the tetragonal phase nano-zirconia composite powder. After washing and drying to remove unreacted components, the specific surface area of ​​the material was significantly increased and it was endowed with carrier function.

[0036] Example 2: This example provides a method for preparing a carrier-type nano-zirconia composite material with a large specific surface area, including the following steps: S1: Add 11.592g zirconium nitrate pentahydrate, 1.303g cerium nitrate hexahydrate, 0.24g yttrium nitrate hexahydrate and 240mL deionized water to a reaction vessel and stir until homogeneous. Add 9mL of 25wt% hydrogen peroxide solution and stir for 50min to obtain a mixed solution. Add the mixed solution dropwise to 60mL of 1.0mol / L ammonia water while maintaining the pH at 10 during the addition to obtain the precursor solution.

[0037] S2: Stir 310 mL of the precursor solution at 20 °C and 300 r / min for 60 min. After the reaction is complete, filter under vacuum, collect the precipitate, wash the precipitate three times with deionized water, and then wash it once with ethanol. Add the washed precipitate, 500 mL of n-butanol and 5 g of glucose to the reaction vessel, and distill at 98 °C for 30 min to obtain the first distillate. Distill the first distillate at 123 °C for 60 min to remove excess n-butanol and obtain the precursor powder.

[0038] S3: The precursor powder was placed in a muffle furnace and heated to 400°C at a heating rate of 5°C / min, and calcined for 1 hour. Then, it was heated to 600°C at a heating rate of 5°C / min and calcined for 3 hours to obtain stable tetragonal phase nano-zirconia composite powder.

[0039] S4: 3.8g of tetragonal phase nano-zirconia composite powder, 9g of zirconium chloride, 8.6g of nitroterephthalic acid and 3L of acetone were added to a reaction vessel and ultrasonically dispersed for 30min. The mixture was heated at 100℃ for 24h under sealed conditions. After the reaction was completed, the mixture was centrifuged and the precipitate was washed three times with acetone and methanol in sequence. The precipitate was dried at 50℃ for 6h to obtain a carrier-type nano-zirconia composite material with a large specific surface area.

[0040] Example 3: This example provides a method for preparing a carrier-type nano-zirconia composite material with a large specific surface area, including the following steps: S1: Add 17.592g zirconium nitrate pentahydrate, 1.703g cerium nitrate hexahydrate, 0.32g yttrium nitrate hexahydrate and 300mL deionized water to a reaction vessel and stir until homogeneous. Add 15mL of 25wt% hydrogen peroxide solution and stir for 60min to obtain a mixed solution. Add the mixed solution dropwise to 80mL of 1.1mol / L ammonia water while maintaining the pH at 10 during the dropwise addition to obtain the precursor solution.

[0041] S2: 400 mL of precursor solution was stirred at 25 °C and 500 r / min for 70 min. After the reaction was completed, the mixture was vacuum filtered to collect the precipitate. The precipitate was washed 5 times with deionized water and then 3 times with ethanol. The washed precipitate, 600 mL of n-butanol and 7 g of glucose were added to the reaction vessel and distilled at 100 °C for 40 min to obtain a first distillate. The first distillate was then distilled at 123 °C for 70 min to remove excess n-butanol and obtain the precursor powder.

[0042] S3: The precursor powder was placed in a muffle furnace and heated to 420°C at a heating rate of 5°C / min, and calcined for 2 hours. Then, it was heated to 640°C at a heating rate of 5°C / min and calcined for 4 hours to obtain stable tetragonal phase nano-zirconia composite powder.

[0043] S4: 4.2g of tetragonal phase nano-zirconia composite powder, 13g of zirconium chloride, 10.6g of nitroterephthalic acid and 4L of acetone were added to a reaction vessel and ultrasonically dispersed for 40min. The mixture was heated at 120℃ for 26h under sealed conditions. After the reaction was completed, the mixture was centrifuged and the precipitate was washed five times with acetone and methanol in sequence. The precipitate was dried at 55℃ for 8h to obtain a carrier-type nano-zirconia composite material with a large specific surface area.

[0044] Example 4: This example provides a method for preparing a carrier-type nano-zirconia composite material with a large specific surface area. The difference from Example 1 is that cerium chloride is used instead of cerium nitrate hexahydrate in step S1. 2 Example 5: This example provides a method for preparing a carrier-type nano-zirconia composite material with a large specific surface area. The difference from Example 1 is that yttrium chloride is used instead of yttrium nitrate hexahydrate in step S1.

[0045] Example 6: This example provides a method for preparing a carrier-type nano-zirconia composite material with a large specific surface area. The difference from Example 1 is that terephthalic acid is used instead of nitroterephthalic acid in step S4.

[0046] Comparative Example 1: This comparative example provides a method for preparing a carrier-type nano-zirconia composite material with a large specific surface area. The difference from Example 1 is that step S4 is omitted. The tetragonal phase nano-zirconia composite powder prepared in step S3 is the carrier-type nano-zirconia composite material with a large specific surface area.

[0047] Comparative Example 2: This comparative example provides a method for preparing a carrier-type nano-zirconia composite material with a large specific surface area. The difference from Example 1 is that yttrium nitrate hexahydrate is removed in step S1.

[0048] Comparative Example 3: This comparative example provides a method for preparing a carrier-type nano-zirconia composite material with a large specific surface area. The difference from Example 1 is that glucose is removed in step S2.

[0049] The photocatalytic performance of the large specific surface area carrier-type zirconia nanocomposites prepared in Examples 1-6 and Comparative Examples 1-3 was tested: first, a concentration of 10 mg / L was prepared... -1 MB (methylene blue) solution was prepared. 10 mg of the carrier-based nano-zirconia composite material was added to the MB solution, and the mixture was stirred for 30 min to reach adsorption-desorption equilibrium. The light source was a 300W xenon lamp equipped with a cutoff filter (<420 nm), with the lamp positioned 10 cm away from the mixed solution. The concentration of MB was measured using a UV-Vis spectrophotometer at 30-minute intervals.

[0050] Specific surface area determination: The test was conducted using a specific surface area and pore size measuring instrument.

[0051] Table 1 Performance Test Overview

[0052] As shown in Table 1, the 30-min, 60-min, and 90-min MB degradation rates of Examples 1-6 were all higher than those of Comparative Examples 1-3. This may be because the large surface area of ​​Examples 1-6 provided a large number of accessible active sites for the photocatalytic reaction. At the same time, the hierarchical channels accelerated the contact between methylene blue molecules and active sites and the desorption of reaction products, achieving a high degradation rate in a short time. In contrast, Comparative Example 1 lacked the Zr-based MOF composite step and only had a single mesoporous structure, resulting in a significantly reduced specific surface area and insufficient number of active sites. Comparative Example 2 lacked yttrium salt doping, which may have caused the pore structure to collapse due to the crystal phase transition, blocking the active sites. Comparative Example 3 lacked glucose pore-forming agent, and the channels were mainly large pores of particle stacking with a small specific surface area, hence the low degradation rate.

[0053] As shown in Table 1, the specific surface area of ​​Examples 1-6 is significantly larger than that of Comparative Examples 1-3. This may be because Examples 1-6 first use Ce-Y dual doping to form a uniform hydroxide precursor, reserving a framework for the pore structure. Then, glucose is used as a pore-forming agent, which decomposes after calcination to form mesopores. At the same time, azeotropic distillation replaces surface hydroxyl groups with butoxy groups to inhibit pore blockage caused by particle agglomeration. Finally, zirconium-based MOFs are grown in situ on the zirconium oxide surface by hydrothermal synthesis, forming a hierarchical pore system. The three factors synergistically improve the specific surface area of ​​the material. In contrast, Comparative Example 1 lacks the MOF composite step and relies only on the substrate mesopores, resulting in a simple pore structure and limited specific surface area. Comparative Example 2 lacks yttrium salt doping, leading to decreased crystal phase stability and partial tetragonal-to-monoclinic phase transformation, which destroys the integrity of the pore structure and reduces the specific surface area. Comparative Example 3 lacks glucose as a pore-forming agent, and no additional mesopores are formed after calcination. The pores mainly rely on particle accumulation.

[0054] It should be noted that, in this document, terms such as “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus.

[0055] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention.

Claims

1. A method for preparing a carrier-type nano-zirconia composite material with a large specific surface area, characterized in that, Includes the following steps: Step 1: Using zirconium nitrate pentahydrate as the zirconium source and ammonia as the hydroxide ion donor, cerium salt and yttrium salt undergo a co-precipitation reaction in an alkaline environment to obtain a precursor solution; Step 2: Fully mature the precursor solution, add a pore-forming agent, remove water by azeotropic distillation to obtain precursor powder; calcine the precursor powder to obtain tetragonal phase nano-zirconia composite powder. Step 3: The tetragonal phase nano-zirconia composite powder is ultrasonically dispersed, and then a zirconium-based MOF is generated in situ on the surface of the tetragonal phase nano-zirconia composite powder by hydrothermal synthesis, resulting in a carrier-type nano-zirconia composite material with a large specific surface area.

2. The method for preparing a carrier-type nano-zirconia composite material with a large specific surface area according to claim 1, characterized in that, The specific preparation process of the precursor solution mentioned in step one is as follows: Zirconium nitrate pentahydrate, cerium salt, yttrium salt, and deionized water were added to a reaction vessel and stirred until homogeneous. A 25 wt% hydrogen peroxide solution was then added and stirred for 50-60 minutes to obtain a mixed solution. The mixed solution was then added dropwise to a 1.0-1.1 mol / L ammonia solution, maintaining the pH at 10 during the addition process to obtain the precursor solution.

3. The method for preparing a carrier-type nano-zirconia composite material with a large specific surface area according to claim 2, characterized in that, The ratio of zirconium nitrate pentahydrate, cerium salt, yttrium salt, deionized water, hydrogen peroxide solution, and ammonia is 11.592-17.592g: 1.303-1.703g: 0.24-0.32g: 240-300mL: 9-15mL: 60-80mL.

4. The method for preparing a carrier-type nano-zirconia composite material with a large specific surface area according to claim 3, characterized in that, The cerium salt is either cerium nitrate hexahydrate or cerium chloride; The yttrium salt is either yttrium nitrate hexahydrate or yttrium chloride.

5. The method for preparing a carrier-type nano-zirconia composite material with a large specific surface area according to claim 1, characterized in that, The specific preparation process of the precursor powder in step two is as follows: The precursor solution was stirred at 20-25℃ and 300-500 r / min for 60-70 min. After the reaction was completed, the mixture was filtered, and the precipitate was washed successively with deionized water and ethanol. The washed precipitate, n-butanol and glucose were then added to a reaction vessel and distilled at 98-100℃ for 30-40 min to obtain a first distillate. The first distillate was then distilled at 123℃ for 60-70 min to obtain the precursor powder.

6. The method for preparing a carrier-type nano-zirconia composite material with a large specific surface area according to claim 5, characterized in that, The ratio of the precursor solution, n-butanol, and glucose is 310-400 mL: 500-600 mL: 5-7 g.

7. The method for preparing a carrier-type nano-zirconia composite material with a large specific surface area according to claim 1, characterized in that, The specific preparation process of the tetragonal phase nano-zirconia composite powder in step two is as follows: The precursor powder was placed in a muffle furnace and heated to 400-420℃ at a heating rate of 5℃ / min, and calcined for 1-2 hours. Then, it was heated to 600-640℃ at a heating rate of 5℃ / min and calcined for 3-4 hours to obtain stable tetragonal phase nano-zirconia composite powder.

8. The method for preparing a carrier-type nano-zirconia composite material with a large specific surface area according to claim 1, characterized in that, The specific preparation process of the carrier-type nano-zirconia composite material with large specific surface area described in step three is as follows: Tetragonal phase nano-zirconia composite powder, zirconium chloride, substituted phthalic acid compounds and acetone were added to a reaction vessel and ultrasonically dispersed for 30-40 min. The mixture was then heated for 24-26 h under sealed conditions and at 100-120 °C. After the reaction was completed, the mixture was centrifuged, washed and dried to obtain a carrier-type nano-zirconia composite material with a large specific surface area.

9. The method for preparing a carrier-type nano-zirconia composite material with a large specific surface area according to claim 8, characterized in that, The ratio of the tetragonal phase nano-zirconia composite powder, zirconium chloride, substituted phthalic acid compounds and acetone is 3.8-4.2g: 9-13g: 8.6-10.6g: 3-4L.

10. The method for preparing a carrier-type nano-zirconia composite material with a large specific surface area according to claim 9, characterized in that, The substituted phthalic acid compound is either nitroterephthalic acid or terephthalic acid.

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