Hollow mesoporous metal-organic framework material, and preparation method and application thereof

Abstract

The present application relates to a kind of hollow mesoporous metal organic framework material and its preparation method and application, its preparation process main steps include as follows: S1: using the incompatibility of organic phase and aqueous phase forms emulsion interface, S2: using amphiphilic surfactant in system forms micelle and metal organic framework material precursor is assembled.S3: using monobasic carboxylic acid and dibasic carboxylic acid ligand and metal node competition coordination, kinetics controls the coordination of ligand and metal node, further controls the nucleation, growth process of metal organic framework material precursor on micelle, and control micelle is assembled on emulsion interface, finally by washing obtain uniform monodisperse hollow mesoporous metal organic framework material.According to the preparation method of the present application, process is simple, repeatability is good, the single crystal particle of hollow mesoporous metal organic framework material obtained, with morphology, channel and component adjustable etc.Advantages, in catalysis, energy and biomedical fields have good application potential.

Description

Technical Field

[0001] This invention belongs to the field of new materials technology, and relates to a hollow mesoporous metal-organic framework material, its preparation method and application. Background Technology

[0002] Metal-organic frameworks (MOFs) are a class of porous materials with unique topological structures, constructed from metal nodes and organic ligands. Due to the rich tunability of functional units such as metal nodes and ligands, they have found wide applications in catalysis, energy, biology, and gas adsorption and separation. Although MOFs possess high specific surface areas and abundant pores, the pore sizes of most MOFs are in the micropore range (<2 nm), which hinders the diffusion and transport of guest substances and severely reduces their performance in these applications. This significantly limits the research and development of MOFs. To address this limitation, mesoporous design or pore-enlarging techniques for MOFs are meaningful and necessary.

[0003] Among various metal-organic framework (MOA) structures, hollow mesoporous MOA materials have attracted widespread attention because they not only retain the intrinsic properties of MOA materials but also effectively combine the advantages of both hollow and mesoporous structures. This can increase their surface area and active sites, and promote material transport and increase macromolecular loading. Recently, several methods for preparing hollow mesoporous MOA materials have been proposed, such as hard template methods, etching methods, or ligand digestion methods. However, these methods have significant drawbacks: for example, template methods require prior template preparation, the presence of the template makes the crystallization of MOA materials difficult, and template removal can easily lead to the collapse of pores and structures; etching methods are cumbersome, the stability of the obtained sample structure is relatively poor, and mesopores and cavities are difficult to control. Therefore, developing a simple, effective, and controllable method for preparing hollow mesoporous MOA materials is a highly valuable and challenging task. Summary of the Invention

[0004] The purpose of this invention is to provide a hollow mesoporous metal-organic framework material, its preparation method, and its application. The invention utilizes an emulsion system and achieves the preparation of hollow mesoporous metal-organic framework nanomaterials through kinetic control of the assembly process. This allows for controllable adjustment of various aspects such as cavity size, pore size, composition, and crystal form.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] One of the technical solutions of the present invention provides a method for preparing a hollow mesoporous metal-organic framework material, comprising the following steps:

[0007] (1) Utilizing the immiscibility of the organic phase and the aqueous phase to form an emulsion interface:

[0008] The oil phase solvent is mixed with water and fully emulsified to obtain a mixed solvent system with an emulsion interface;

[0009] (2) Amphiphilic surfactants are used to form micelles in the system for assembly with precursors of metal-organic framework materials. At the same time, monocarboxylic acid and dicarboxylic acid ligands compete with metal nodes for coordination, and the coordination of ligands and metal nodes and their assembly with micelles are kinetically regulated:

[0010] Add an amphiphilic surfactant, ligand, ligand solubilizer and regulator to the mixed solvent system of step (1), add metal ions, and then carry out an oil bath reaction. Centrifuge and wash the resulting product and remove the template to obtain the target product.

[0011] Furthermore, in step (1), the oil phase solvent is one or a combination of several of the following: mesitylene, xylene, toluene, benzene, cyclohexane, or n-hexane.

[0012] Furthermore, in step (1), the volume ratio of the oil phase solvent to water is 1:10 to 10:1.

[0013] Further, in step (2), the amphiphilic surfactant is at least one of the following: polyoxyethylene-b-polyoxypropylene-b-polyoxyethylene triblock copolymers: Pluronic P123 (EO20PO70EO20), Pluronic F127 (EO106PO70EO106), Pluronic P103 (EO17PO56EO17), Pluronic P85 (EO26PO39EO26), Pluronic P65 (EO20PO30EO20), Pluronic L121 (EO5PO70EO5), Pluronic F88 (EO100PO39EO100), Pluronic F98 (EO123PO47EO123), Pluronic F108 (EO132PO50EO132), polyoxyethylene-b-polystyrene (PEO-b-PS), and polyoxyethylene-b-polymethyl methacrylate (PEO-b-PMMA).

[0014] Furthermore, in step (2), the regulator is a monocarboxylic acid selected from at least one of formic acid, acetic acid, propionic acid, and benzoic acid.

[0015] Furthermore, in step (2), the ligand is a dicarboxylic acid selected from one or more of terephthalic acid, aminoterephthalic acid, mercaptoterephthalic acid, and sulfonic acid terephthalic acid; the ligand solubilizer is at least one of NaClO4, NaSCN, NaNO3, NaI, and arginine. Furthermore, in step (2), the metal salt providing the metal ion is at least one of Ce(NH4)2(NO3)6, ZrO(NO3)6, and AlCl3·6H2O.

[0016] Furthermore, in step (2), the mass ratio of the amphiphilic surfactant to the metal salt that provides the metal ions is 1:5 to 10:1, the molar ratio of the metal salt that provides the metal ions to the ligand is 1:2 to 1:1, the molar ratio of the ligand to the ligand solubilizer is 1:1 to 1:20, and the molar ratio of the ligand to the regulator is 1:10 to 10:1.

[0017] Furthermore, in step (2), the temperature of the oil bath reaction is 0 to 200°C, and the time is 20 min to 48 h.

[0018] The working principle of this invention is as follows:

[0019] First, by using amphiphilic surfactants as soft templates, the assembly of the template agent at the oil-water interface can be effectively controlled due to the principle of "like dissolves like," and the cavity size can be adjusted by regulating the oil-water ratio in the emulsion system. Second, due to the differences in the length (volume) of hydrophilic and hydrophobic segments of different template agents, the pore size can be effectively adjusted by regulating the type or composition of the template agent. Third, by utilizing the competitive coordination between monocarboxylic acids (regulators) and dicarboxylic acids (ligands), the nucleation and grain growth of metal ions can be controlled, achieving the transformation from polycrystalline to monocrystalline, and simultaneously the transformation from hollow mesoporous spheres to octahedrons. This metal-organic framework material possesses open channels and a stable hollow mesoporous structure, laying the foundation for its applications in catalysis, batteries, supercapacitors, and biomedicine.

[0020] The second technical solution of the present invention provides a hollow mesoporous metal-organic framework material, which is prepared by any of the preparation methods described above. The framework material is characterized in that the cavity size is 50-500 nm, the pore size is 5-100 nm, the pore structure is spherical, columnar, or layered, the shell thickness is 100-400 nm, and it is spherical, rounded octahedral, or octahedral.

[0021] The third technical solution of the present invention provides an application of hollow mesoporous metal-organic framework materials in the fields of catalysis, batteries, supercapacitors and biomedicine.

[0022] Compared with the prior art, the present invention has the following advantages:

[0023] (1) The hollow mesoporous metal-organic framework material particles of the present invention have typical hollow and mesoporous structures. By adjusting the interface of the emulsion, the cavity size of the hollow structure can be made to be 50-500 nm. By controlling the proportion or composition of the template agent, the pore size of the mesopores can be adjusted between 5-100 nm, and it can have spherical channels or divergent columnar channel structures. By controlling the assembly kinetics, the particles can have spherical or octahedral morphologies, and the particle size is 500-1000 nm.

[0024] (2) The process is simple and reproducible. The hollow mesoporous metal-organic framework material single crystal particles obtained have advantages such as tunable morphology, channels and composition, and have good application potential in catalysis, energy and biomedicine. Attached Figure Description

[0025] Figure 1 The image shows a scanning electron microscope (SEM) image of hollow mesoporous UiO-66(Ce) obtained using different amounts of trimethylbenzene in Example 1.

[0026] Figure 2 The image shown is a scanning electron microscope image of hollow mesoporous UiO-66(Zr) obtained in Example 4.

[0027] Figure 3 The time-voltage curves for zinc anode deposition and stripping are shown for the spherical hollow mesoporous UiO-66(Ce) used as the separator in an aqueous Zn-Zn symmetric battery in Example 5.

[0028] Figure 4 The photocatalytic hydrogen evolution performance curve of the octahedral hollow mesoporous UiO-66(Ce) single crystal in Example 5 is shown. Detailed Implementation

[0029] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0030] In the following embodiments, unless otherwise specified, the raw materials or processing techniques are conventional commercially available raw materials or conventional processing techniques in the art.

[0031] Example 1:

[0032] Dissolve 900 mg P123 and 900 mg F127 in 18 mL of deionized water. Add 2 mL of mesitylene to the solution and stir rapidly for 5 min. Sonicate for 5 min, and during sonication, add 0.5 mL of acetic acid and 1500 mg NaClO4·H2O. After sonication, transfer the mixture to a 60°C oil bath. Weigh 564 mg of terephthalic acid and add it to the solution. Stir for 5 min, then add 1644 mg of cerium ammonium nitrate. Continue stirring for 40 min. Wash the product obtained in the solution three times each with alternating centrifugation using N,N-dimethylformamide, anhydrous ethanol, and water. Then, redisperse the solid product in anhydrous ethanol and place it in a 60°C oil bath. Stir continuously for 48 h, changing the ethanol twice during this period to completely remove the surfactant used previously. Wash the product three times again with ethanol and dry overnight in a 60°C vacuum drying oven to obtain hollow spherical mesoporous UiO-66(Ce)( Figure 1 a, b).

[0033] Example 2:

[0034] 900mg P123 and 900mg F127 was dissolved in 18 ml of deionized water. 2 mL of mesitylene was added to the solution, and the mixture was stirred rapidly for 5 min. The mixture was then sonicated for 5 min. During sonication, 0.7 mL of acetic acid and 1500 mg of NaClO4·H2O were added. After sonication, the mixture was transferred to a 60°C oil bath. 564 mg of terephthalic acid was added to the solution, and the mixture was stirred for 5 min. 1644 mg of cerium ammonium nitrate was then added, and the reaction was continued to be stirred for 40 min. The product obtained in the solution was washed three times each by alternating centrifugation with N,N-dimethylformamide, anhydrous ethanol, and water. The resulting solid product was then redispersed in anhydrous ethanol and placed in a 60°C oil bath. The mixture was stirred continuously for 48 h, with the ethanol being replaced twice during this period to completely remove the surfactant used previously. The product was washed three times again by centrifugation with ethanol and then dried overnight in a 60°C vacuum drying oven to obtain hollow, rounded-corner octahedral spherical mesoporous UiO-66(Ce)( Figure 1 c, b).

[0035] Example 3:

[0036] Dissolve 900 mg P123 and 900 mg F127 in 18 mL of deionized water. Add 2 mL of mesitylene to the solution and stir rapidly for 5 min, followed by sonication for 5 min. During sonication, add 0.9 mL of acetic acid and 1500 mg of NaClO4·H2O. After sonication, transfer the mixture to a 60°C oil bath. Weigh 564 mg of terephthalic acid and add it to the solution. Stir for 5 min, then add 1644 mg of cerium ammonium nitrate. Continue stirring for 40 min. Wash the product obtained from the solution three times each with alternating centrifugation using N,N-dimethylformamide, anhydrous ethanol, and water. Then, redisperse the solid product in anhydrous ethanol and place it in a 60°C oil bath, stirring continuously for 48 h, changing the ethanol twice during this period to completely remove the surfactant used previously. Wash the product three times again with ethanol by centrifugation and dry overnight in a 60°C vacuum drying oven to obtain hollow spherical mesoporous UiO-66(Ce)( Figure 1 e, f).

[0037] Example 4:

[0038] Dissolve 300 mg P123 and 300 mg F127 in 12 ml of deionized water. Measure 1.5 mL of n-hexane and add it to the above solution. Stir rapidly for 5 min and sonicate for 5 min. During sonication, measure a certain amount of 0.4 mL acetic acid and 600 mg NaClO4·H2O. After sonication, transfer the above mixed solution to a 40°C water bath. Weigh 200 mg of aminoterephthalic acid and add it to the solution. Stir rapidly for 5 min and then add 460 mg of [unspecified substance]. ZrO(NO3)6 was reacted with stirring for 12 hours. The product obtained from the above solution was washed three times each by alternating centrifugation with N,N-dimethylformamide, anhydrous ethanol, and water. The resulting solid product was then redispersed in anhydrous ethanol and placed in a 40°C water bath with stirring for 48 hours, during which the ethanol was replaced twice to completely remove the surfactant used previously. The product was then washed three times again by centrifugation with ethanol and dried overnight in a vacuum drying oven at 60°C to obtain hollow spherical mesoporous UiO-66(Zr)( Figure 2 ).

[0039] Example 5:

[0040] Hollow spherical mesoporous UiO-66(Ce) polycrystalline material from Example 1 was selected, mixed uniformly with commercial nanocellulose, and then filtered to form a membrane, which can be directly used as an aqueous zinc ion exchange membrane. When using 2M ZnSO4 as the electrolyte and UiO-66(Ce) polycrystalline / nanocellulose as the membrane, the assembled Zn-Zn symmetric battery achieved a performance of 1 mAh cm⁻¹. -2 Surface capacity, 5mA cm-2 At a current density of [value missing], it can cycle stably for at least 1000 hours, and the polarization voltage is around 80mV. Figure 3 Hollow octahedral mesoporous UiO-66(Ce) single crystals from Example 3 were selected as the water splitting photocatalyst. Using Na₂S and Na₂S₂O₃ as sacrificial agents, it exhibited a photocatalyst of 362 μmol g⁻¹. – 1 h –1 hydrogen production rate ( Figure 4 ).

[0041] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A method for preparing a hollow mesoporous metal-organic framework material, characterized in that, Includes the following steps: Dissolve 900 mg P123 and 900 mg F127 in 18 mL of deionized water. Measure 2 mL of mesitylene and add it to the above solution. Stir rapidly for 5 min and sonicate for 5 min. During sonication, measure 0.5 mL of acetic acid and 1500 mg NaClO4·H2O and add them to the above solution. After sonication, transfer the above solution to an oil bath at 60 °C. Weigh 564 mg of terephthalic acid and add it to the above solution. Stir for 5 min and then add 1644 mg of cerium ammonium nitrate. Continue stirring the reaction for 40 min. Wash the products obtained in the above solution three times each with N,N-dimethylformamide, anhydrous ethanol, and water by centrifugation. Then, disperse the obtained solid product again in anhydrous ethanol and place it in an oil bath at 60 °C. Stir continuously for 48 h, changing the ethanol twice during the period to completely remove the surfactant used above. Wash the product three times again with ethanol by centrifugation and dry it overnight in a vacuum drying oven at 60 °C to obtain the hollow mesoporous metal-organic framework material. The hollow mesoporous metal-organic framework material is used in batteries and photocatalytic hydrogen production.

Images