Three-dimensional covalent organic framework material based on double three-dimensional centers, preparation method of three-dimensional covalent organic framework material and application of three-dimensional covalent organic framework material in hydrogen storage
By preparing a three-dimensional covalent organic framework material based on a dual stereocenter, the problem of reduced specific surface area caused by structural interpenetration during the growth of three-dimensional COF materials was solved, achieving high specific surface area and abundant adsorption sites, thereby improving the storage and adsorption performance of hydrogen.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-29
- Publication Date
- 2026-04-10
AI Technical Summary
Existing three-dimensional covalent organic framework materials tend to form interpenetrating structures during growth, which leads to a decrease in specific surface area and active sites, affecting gas adsorption and storage performance.
A method for preparing three-dimensional covalent organic framework materials based on dual stereocenters was adopted. A non-interpenetrating dia topology was constructed by freezing 1,3,5,7-tetra(4-benzaldehyde)-adamantane with tetra(4-aminophenyl)methane or tetra(4-aminobiphenyl)methane in liquid nitrogen. Acetic acid was used as a solvent to perform multiple washing and drying processes to obtain a high specific surface area and exposed adsorption sites.
The high specific surface area and abundant adsorption sites of the three-dimensional covalent organic framework material were achieved, which improved the hydrogen adsorption performance, especially showing excellent hydrogen storage capacity under high pressure conditions.
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Abstract
Description
Technical Field
[0001] This invention relates to a three-dimensional covalent organic framework material based on a dual stereocenter, its preparation method, and its application in hydrogen storage, belonging to the technical field of hydrogen storage materials and their preparation. Background Technology
[0002] Covalent organic frameworks (COFs) are a class of organic crystalline porous materials composed of light elements (such as C, H, O, N, B, etc.), with molecules linked by reversible covalent bonds (such as imine bonds, borate ester bonds, etc.) to form periodic structures. This reversibility endows COFs with self-healing and high crystallinity. By designing different building blocks, topologies, and connection methods, researchers can precisely control their pore size, pore structure, and functional sites. COFs possess high specific surface area, low density, excellent thermal / chemical stability, and good designability, and are widely used in gas adsorption and separation, catalysis, sensing, and other fields. Three-dimensional covalent organic framework materials have a three-dimensional network topology, and can be synthesized by selecting three-dimensional building blocks. They have a higher theoretical specific surface area and more complex pore structures, thus offering advantages in gas adsorption and other applications. However, during the growth process, three-dimensional COFs tend to form interlocking structures to maintain better stability, but this reduces the specific surface area and active sites, resulting in poorer performance in gas adsorption and storage applications. Therefore, it is essential to regulate the degree of penetration of three-dimensional COFs, construct non-penetrating structures, increase specific surface area, increase the number of active sites, and thus improve gas adsorption performance. Summary of the Invention
[0003] To further improve the gas adsorption capacity of existing COF hydrogen storage materials, this invention provides a three-dimensional covalent organic framework material based on dual stereocenters, its preparation method, and its application in hydrogen storage.
[0004] The technical solution of this invention: One objective of this invention is to provide a method for preparing a three-dimensional covalent organic framework material based on a dual stereocenter. The method involves adding 1,3,5,7-tetra(4-benzaldehyde)-adamantane and tetra(4-aminophenyl)methane or tetra(4-aminobiphenyl)methane to a 1,4-dioxane system, freezing the reaction system in liquid nitrogen, sealing the tube, and then performing the reaction. After the reaction is completed, post-processing is performed to obtain a three-dimensional covalent organic framework material based on a dual stereocenter.
[0005] Further specified, the ratio of 1,3,5,7-tetra(4-benzaldehyde)-adamantane, tetra(4-aminophenyl)methane or tetra(4-aminobiphenyl)methane, 1,4-dioxane and acetic acid is 0.05 mmol:0.05 mmol:1.0 mL:0.1 mL, and the concentration of acetic acid is 6.0 M.
[0006] Further, after sealing, the tube was placed in an oven at 120°C for reaction.
[0007] Further specifying the post-processing steps: after the reaction is complete, open the glass tube with a glass cutter, wash the product multiple times with acetone, with each wash interval not less than 1 hour, then soak the product in acetone or tetrahydrofuran solution, and finally filter and dry.
[0008] Furthermore, the product must be washed with acetone at least six times.
[0009] Furthermore, the product must be soaked in acetone or tetrahydrofuran solution for at least 8 hours.
[0010] Furthermore, the drying process is carried out in a vacuum drying oven at 85°C for 2 hours.
[0011] The second objective of this invention is to provide a three-dimensional covalent organic framework material based on a dual stereocenter prepared by the above method.
[0012] Further specifying, this three-dimensional covalent organic framework material has a dia topology.
[0013] The third objective of this invention is to provide an application of the above-mentioned three-dimensional covalent organic framework material based on dual stereocenters, specifically as a hydrogen storage material for the storage and transportation of hydrogen.
[0014] Beneficial effects: This invention directly condenses two tetrahedral building blocks to construct a three-dimensional covalent organic framework (COF) with a non-interpenetrating dia topology. This COF exhibits good crystallinity and a high BET specific surface area. Utilizing its higher specific surface area and fully exposed high-energy adsorption sites resulting from its non-interpenetrating structure, as well as the high-density stereo central units and imine nitrogen atoms within the framework providing high-energy adsorption sites, it demonstrates excellent hydrogen adsorption performance, contributing to an increase in hydrogen adsorption capacity. Attached Figure Description
[0015] Figure 1 The XRD refinement curve of TAM-TFPA-COF prepared in Example 1; Figure 2 The XRD refinement curve of TABPM-TFPA-COF prepared in Example 2; Figure 3N2 adsorption-desorption curves of TAM-TFPA-COF prepared in Example 1 at 77K; Figure 4 N2 adsorption-desorption curves of TABPM-TFPA-COF prepared in Example 2 at 77K; Figure 5 Hydrogen adsorption-desorption curves of TAM-TFPA-COF and TABPM-TFPA-COF at 1 bar and different temperatures; Figure 6 Hydrogen adsorption curves of TAM-TFPA-COF and TABPM-TFPA-COF at 77K and different pressures. Detailed Implementation
[0016] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the examples in the specification.
[0017] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art may make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.
[0018] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.
[0019] Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Unless otherwise specified, the materials, reagents, methods, and instruments used are all conventional materials, reagents, methods, and instruments in the art, and can be obtained commercially by those skilled in the art.
[0020] Example 1: The method for preparing the three-dimensional covalent organic framework material TAM-TFPA-COF based on a dual stereocenter in this embodiment is as follows: 1,3,5,7-Tetra(4-benzaldehyde)-adamantane (TFPA, 26.1 mg, 0.05 mmol) and tetra(4-aminophenyl)methane (TAM, 19.0 mg, 0.05 mmol) were added to a 10 × 8 mm² glass tube. A mixed solution of anhydrous dioxane (1.0 mL) and 6.0 M acetic acid (0.10 mL) was then added. The bottom of the glass tube containing the reactants was then placed in liquid nitrogen to freeze the reaction system, and the tube was sealed under a methane / oxygen flame. The sealed glass tube reaction system was placed in an oven at 120°C for 72 h. After the reaction, the glass tube was opened with a glass cutter, and the product was washed with acetone at least six times, with each wash at least 1 h apart. The product was then immersed in acetone for more than 8 h, followed by filtration. The resulting solid product was dried in a vacuum drying oven at 85°C for 2 h to obtain the target product, named TAM-TFPA-COF. The product is a pale yellow solid with a yield of 81% and a weight of 36.5 mg.
[0021] Example 2: The method for preparing the three-dimensional covalent organic framework material TABPM-TFPA-COF based on a dual stereocenter in this embodiment is as follows: 1,3,5,7-Tetra(4-benzaldehyde)-adamantane (TFPA, 26.1 mg, 0.05 mmol) and tetra(4-aminobiphenyl)methane (TABPM, 34.2 mg, 0.05 mmol) were added to a 10 × 8 mm² glass tube. A mixed solution of anhydrous dioxane (1.0 mL) and 6.0 M acetic acid (0.10 mL) was then added. The bottom of the glass tube containing the reactants was then placed in liquid nitrogen to freeze the reaction system, and the tube was sealed under a methane / oxygen flame. The sealed glass tube reaction system was placed in an oven at 120°C for 72 h. After the reaction, the glass tube was opened with a glass cutter, and the product was washed with acetone at least six times, with each wash at least 1 h apart. The product was then immersed in acetone for more than 8 h, followed by filtration. The resulting solid product was dried in a vacuum drying oven at 85°C for 2 h to obtain the target product, named TABPM-TFPA-COF. The product is a pale yellow solid with a yield of 73% and a weight of 44.1 mg.
[0022] The crystal structures of TAM-TFPA-COF prepared in Example 1 and TABPM-TFPA-COF prepared in Example 2 were determined using PXRD, and their crystal structures were refined using DFT calculations. The results are as follows: Figure 1 and Figure 2 As shown by the red curve in the middle, a framework with a dia topology was constructed based on the 4+2 connection type, and geometric energy minimization simulations were performed. The fitting results are as follows: Figure 1 and Figure 2As shown by the black curve in the middle, the comparison shows that the experimental results and the fitting results are in good agreement.
[0023] The TAM-TFPA-COF prepared in Example 1 and the TABPM-TFPA-COF prepared in Example 2 were subjected to Pawley refinement with a non-interpenetrating dia topology, yielding the TAM-TFPA-COF unit cell parameters (a=b=21.202Å, c=35.039Å, α=β=γ=90°) and space group [missing information]. I-4 The refined indices Rwp and Rp are 9.85% and 5.95%, respectively. The diffraction peaks at 5.04°, 7.75°, 8.33°, and 12.01° can be attributed to the (002), (112), (200), and (123) crystal planes. The TABPM-TFPA-COF unit cell parameters (a=b=28.663Å, c=43.118Å, α=β=γ=90°) and space group are obtained. I-4 The refinement indices Rwp and Rp are 0.99% and 0.76% respectively. The diffraction peaks at 3.70° and 5.98° can be attributed to the (101) and (112) crystal planes.
[0024] To determine the porosity of TAM-TFPA-COF prepared in Example 1 and TABPM-TFPA-COF prepared in Example 2, N2 adsorption-desorption analysis was performed at 77 K. The results are as follows: Figure 3 and Figure 4 As shown, the specific surface area of AM-TFPA-COF, calculated using the Brunauer–Emmett–Teller (BET) model, is 2406.5 m². 2 / g, the specific surface area of TABPM-TFPA-COF is 2204.1m². 2 / g.
[0025] Hydrogen adsorption tests were performed on TAM-TFPA-COF prepared in Example 1 and TABPM-TFPA-COF prepared in Example 2. Figure 5 The hydrogen adsorption-desorption curves of TAM-TFPA-COF and TABPM-TFPA-COF at 1 bar and different temperatures are shown. Figure 6The figure shows the hydrogen adsorption curves of TAM-TFPA-COF and TABPM-TFPA-COF at 77 K and different pressures. As shown in the figure, at 77 K and 1 bar, the hydrogen storage capacity of TAM-TFPA-COF is 2.25 wt%. Within the pressure range of 0-35 bar, the excess adsorption increases with increasing hydrogen pressure, reaching a maximum of 5.28 wt% at 30 bar. Above 35 bar, the excess adsorption decreases with increasing pressure, with a total adsorption capacity of 6.60 wt% at 70 bar. At 77 K and 1 bar, the hydrogen storage capacity of TABPM-TFPA-COF is 1.95 wt%. Within the pressure range of 0-35 bar, the excess adsorption increases with increasing hydrogen pressure, reaching a maximum of 4.87 wt% at 30 bar. Above 35 bar, the excess adsorption decreases with increasing pressure, with a total adsorption capacity of 6.51 wt% at 70 bar. This is because TABPM-TFPA-COF has longer chain segments and larger open cavities, so its hydrogen storage capacity is less than that of TAM-TFPA-COF at low pressure, but the hydrogen storage capacity is similar at high pressure.
[0026] The above description is only a preferred embodiment of the present invention. Given that those skilled in the art can make appropriate changes and modifications to the above embodiments, the present invention is not limited to the specific embodiments described above, and some modifications and changes to the present invention should also fall within the protection scope of the claims of the present invention.
Claims
1. A method for preparing a three-dimensional covalent organic framework material based on a dual stereocenter, characterized in that, 1,3,5,7-Tetra(4-benzaldehyde)-adamantane and tetra(4-aminophenyl)methane or tetra(4-aminobiphenyl)methane were added to a 1,4-dioxane-acetic acid system. The reaction system was frozen in liquid nitrogen, sealed in a tube, and then reacted. After the reaction was completed, post-processing was performed to obtain a three-dimensional covalent organic framework material based on a dual stereocenter.
2. The preparation method according to claim 1, characterized in that, The ratio of 1,3,5,7-tetra(4-benzaldehyde)-adamantane, tetra(4-aminophenyl)methane or tetra(4-aminobiphenyl)methane, 1,4-dioxane and acetic acid was 0.05 mmol:0.05 mmol:1.0 mL:0.1 mL, and the concentration of acetic acid was 6.0 M.
3. The preparation method according to claim 1, characterized in that, After sealing, the tubes are placed in an oven at 120°C for reaction.
4. The preparation method according to claim 1, characterized in that, The post-processing steps are as follows: After the reaction is completed, the glass tube is opened with a glass cutter, and the product is washed multiple times with acetone, with each wash interval being no less than 1 hour. Then, the product is soaked in acetone or tetrahydrofuran solution, and finally filtered and dried.
5. The preparation method according to claim 4, characterized in that, The product was washed with acetone more than 6 times.
6. The preparation method according to claim 4, characterized in that, The product is soaked in acetone or tetrahydrofuran solution for more than 8 hours.
7. The preparation method according to claim 4, characterized in that, The product is dried in a vacuum drying oven at 85°C for 2 hours.
8. A three-dimensional covalent organic framework material based on a dual stereocenter prepared by the method described in any one of claims 1 to 7.
9. The three-dimensional covalent organic framework material based on a dual stereocenter according to claim 8, characterized in that, This three-dimensional covalent organic framework material has a dia topology.
10. An application of a three-dimensional covalent organic framework material based on a dual stereocenter as described in claim 8 or 9, characterized in that, It is used as a hydrogen storage material for the storage and transportation of hydrogen.