A two-dimensional vinyl covalent organic framework material and its preparation method and application

Abstract

The present invention relates to the technical field of inorganic functional materials, and in particular to a two-dimensional vinyl covalent organic framework material and a preparation method and application thereof, comprising a vinyl covalent organic framework and a monodisperse metal anchored on the framework. In the material of the present invention, the π conjugated system of the vinyl COFs itself ensures the high electrical conductivity of the material, and the connection mode of the carbon-carbon double bond ensures long-term catalytic stability, which is suitable for commercial mass production. The highly stable low-metal-loaded COFs material can be used to prepare efficient acidic OER catalysts, has excellent catalytic performance in acidic oxygen electrode catalytic reactions, and has faster OER catalytic reaction kinetics. The preparation method provided by the present invention is conducive to increasing the number and density of catalytic active sites, greatly improving the acidic OER activity. The two-dimensional vinyl covalent organic framework material of the present invention can be applied to the acidic oxygen evolution reaction and used as an acidic oxygen evolution reaction electrocatalyst.

Description

Technical Field

[0001] The present invention relates to the technical field of inorganic functional materials, and in particular to a two-dimensional vinyl covalent organic framework material and a preparation method and application thereof. Background Art

[0002] Against the backdrop of the overuse of fossil fuels and the increasing pressure to control environmental pollution, the development of clean and environmentally friendly energy conversion and storage devices is urgently needed. The utilization of green and renewable energy, mainly hydrogen energy, provides a solution to promote energy innovation. Proton exchange membrane water electrolyzer (PEMWE) technology has great commercial value due to its advantages such as environmental friendliness, low energy consumption, high current density, and high hydrogen production purity. However, its harsh strongly acidic electrolyte environment and the strong oxidation potential of the oxygen electrode place high demands on the stability of the electrocatalyst. Currently, commercial PEMWE uses iridium dioxide as the oxygen electrode catalyst, but its high price and mining speed hinder the large-scale production of PEMWE systems. RuO2, as an alternative to IrO2, is relatively cheap and can alleviate the dilemma of IrO2. However, Ru-based catalysts also face the problem of poor stability in acidic environments. Therefore, the key to achieving efficient and sustainable water splitting is to deeply understand the catalytic reaction mechanism of the oxygen electrode to guide the development of efficient and stable acidic OER electrocatalysts.

[0003] Reticle chemistry offers a promising approach for designing electrocatalysts with abundant active sites, clear structure-activity relationships, and customizable structures. Covalent organic frameworks (COFs) are a class of highly crystalline, porous polymers with well-defined periodic structures. Their chemical structure and topology can be rationally designed and tailored, and fundamental structure-property relationships can be established to understand catalytic mechanisms. Consequently, they have attracted widespread attention in the field of electrocatalysis. Currently, COFs have been used in OER catalysis only in alkaline electrolytes, and their catalytic performance is significantly inferior to that of commercial IrO2. This is because conventional COF-based OER electrocatalysts are constructed via an imine condensation reaction, and the imine bond rapidly hydrolyzes in strong acidic environments, limiting their commercial application. Therefore, COFs can be structurally tailored to enhance catalytic activity while further reducing the active metal loading. Based on this approach, a highly stable vinyl COF was constructed via the Knoevenagel condensation reaction. The bipyridine units within the COF structure enable monodisperse loading of active metal atoms, and the COF was applied to acidic oxygen electrode catalysis. Summary of the Invention

[0004] One of the purposes of the present invention is to provide a two-dimensional vinyl covalent organic framework material. The π conjugated system of vinyl COFs itself ensures the high conductivity of the material, and the connection mode of carbon-carbon double bonds ensures long-term catalytic stability, which is suitable for commercial mass production.

[0005] The second object of the present invention is to provide a two-dimensional vinyl covalent organic framework material and a preparation method thereof. The preparation process is simple and easy to adjust, which is beneficial to increasing the number and density of catalytic active sites and greatly improving the acidic OER activity.

[0006] A third object of the present invention is to provide an application of a two-dimensional vinyl covalent organic framework material.

[0007] The solution adopted by the present invention to achieve one of the purposes is: a two-dimensional vinyl covalent organic framework material, including a vinyl covalent organic framework and a monodisperse metal anchored on the framework.

[0008] Preferably, the structural formula of the two-dimensional vinyl covalent organic framework material is:

[0009]

[0010] Here, M is any one of Ru, Ir, Pd, Pt, Rh, Ni, Co, and Fe.

[0011] The two-dimensional vinyl covalent organic framework material is any one of COF-205-Ru, COF-205-Ir, COF-205-Pd, COF-205-Pt, COF-205-Rh, COF-205-Ni, COF-205-Co, and COF-205-Fe.

[0012] The solution adopted by the present invention to achieve the second purpose is: a method for preparing the two-dimensional vinyl covalent organic framework material, which uses the Knoevenagel reaction to prepare the two-dimensional vinyl covalent organic framework material under sealed tube conditions, including the following steps: 2,2',6,6'-tetramethyl-4,4'-bipyridine, 2,2'-bipyridine-5,5'-dicarboxaldehyde, benzoic acid and benzoic anhydride are uniformly mixed, and reacted under vacuum conditions at 160-200°C; the reaction product is activated and then immersed in a solution containing a metal salt for loading.

[0013] Preferably, the solvent in the solution containing the metal salt is water, or a mixed solvent consisting of water and any one of methanol, ethanol, and tetrahydrofuran; the metal salt is any one of ruthenium chloride, iridium chloride, palladium chloride, chloroplatinic acid, rhodium chloride, ferric chloride, ferric nitrate, cobalt chloride, cobalt nitrate, nickel chloride, and nickel nitrate.

[0014] Preferably, the molar ratio of the 2,2',6,6'-tetramethyl-4,4'-bipyridine, 2,2'-bipyridine-5,5'-dicarbaldehyde, benzoic acid and benzoic anhydride is 1:(1.5-2.5):(0.1-0.3):(1.5-2.5).

[0015] Preferably, the activation step comprises: grinding the product collected after the reaction and adding it to a mixed solution of anhydrous methanol or anhydrous ethanol and 1.0M NaOH solution in a volume ratio of 1: (0.5-1.5) to soak and remove impurities; then adding the product to a mixed solution of anhydrous methanol or anhydrous ethanol and acetone or tetrahydrofuran in a volume ratio of 1: (0.5-1.5) to wash.

[0016] Preferably, the concentration of the metal salt-containing solution is 0.5-4 mg / mL; and the mass ratio of the vinyl covalent organic framework to the metal salt is 4:1 to 1:2.

[0017] Preferably, the load is mixed uniformly by ultrasound, the load temperature is 25-90° C., and the temperature is kept for 6-24 hours.

[0018] The solution adopted by the present invention to achieve the third purpose is: an application of the two-dimensional vinyl covalent organic framework material, wherein the two-dimensional vinyl covalent organic framework material is used as a catalyst in an acidic oxygen evolution reaction.

[0019] The present invention has the following advantages and beneficial effects:

[0020] 1. The two-dimensional vinyl covalent organic framework material of the present invention, the π conjugated system of vinyl COFs itself ensures the high conductivity of the material, and the connection mode of carbon-carbon double bonds ensures long-term catalytic stability, which is suitable for commercial mass production. The highly stable low-metal-loaded COFs material can be used to prepare efficient acidic OER catalysts, has excellent catalytic performance in acidic oxygen electrode catalytic reactions, and has faster OER catalytic reaction kinetics.

[0021] 2. The preparation method provided by the present invention is conducive to increasing the number and density of catalytic active sites, reducing dependence on traditional iridium-based catalysts, and greatly improving acidic OER activity.

[0022] 3. The two-dimensional vinyl covalent organic framework material of the present invention can be applied to the acidic oxygen evolution reaction and used as an electrocatalyst for the acidic oxygen evolution reaction. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Schematic diagram of the synthesis and structure of the support (COF-205) of the catalyst COF-205-Ru prepared in Example 1 of the present invention;

[0024] Figure 2 is the X-ray diffraction pattern of the catalyst prepared in Comparative Example 1 of the present invention;

[0025] Figure 3 The catalyst COF-205-Ru prepared in Comparative Example 1 of the present invention is 13 C solid-state NMR spectrum;

[0026] Figure 4 This is the nitrogen adsorption spectrum of the catalyst COF-205-Ru prepared in Comparative Example 1 of the present invention;

[0027] Figure 5 is a transmission electron microscope image of the COF-205-Ru catalyst prepared in Comparative Example 1 of the present invention;

[0028] Figure 6 This is the mapping diagram of the COF-205-Ru catalyst prepared in Comparative Example 1 of the present invention;

[0029] Figure 7 The OER polarization curves and Tafel plots of the catalyst COF-205-Ru prepared in Comparative Example 1 of the present invention and the comparative catalyst COF-205 and commercial RuO2 in an Ar-saturated 0.5M H2SO4 solution are shown;

[0030] Figure 8 The comparison of the activity of COF-205-Ru before and after OER stability of the catalyst prepared in Comparative Example 1 of the present invention is shown;

[0031] Figure 9 1 is the X-ray diffraction pattern of COF-205-M with different metal loadings of the present invention. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is described in detail below with reference to the accompanying drawings and specific embodiments. It should also be noted that, in order to avoid obscuring the present invention due to unnecessary details, only the structures and / or processing steps closely related to the solutions of the present invention are shown in the accompanying drawings, and other details that are not closely related to the present invention are omitted.

[0033] In addition, it should be noted that the terms "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements that are inherent to such process, method, article or apparatus.

[0034] The outstanding features and significant improvements of the present invention are further illustrated below by way of examples, which are intended only to illustrate the present invention and in no way to limit the present invention.

[0035] Example 1

[0036] Preparation method of two-dimensional vinyl covalent organic framework material (COF-205-Ru) catalyst:

[0037] Weigh 0.4 mmol of 2,2',6,6'-tetramethyl-4,4'-bipyridine, 0.8 mmol of 2,2'-bipyridine-5,5'-dicarbaldehyde, 0.08 mmol of benzoic acid and 0.8 mmol of benzoic anhydride in a glass tube and mix them evenly. Then, remove the air and water vapor in the system by means of ventilation and seal the tube under vacuum conditions. -1 The temperature was raised to 180°C at a rate and kept warm for 72 hours. After the reaction, the product was collected, ground and added with an appropriate amount of anhydrous methanol and 1.0M NaOH solution in a 1:1 ratio, soaked for 24 hours to remove impurities, and the solid was taken out. Then an appropriate amount of anhydrous methanol and acetone in a 1:1 ratio was added and soaked for 3 hours. The solution was changed and washed three times. The washed product was ground at high speed for 1 hour and dried under vacuum. Take 20 mg of the prepared two-dimensional vinyl covalent organic framework material (COF-205), add 10 mL of 1 mg / mL RuCl3 solution, mix evenly with ultrasound and precipitate at 2°C min -1 The temperature was raised to 90°C at a rate of 1000 ℃ and kept at this temperature for 6 hours for loading. After the loading was completed, a mixed solution of water and anhydrous ethanol was added to collect and wash the product, and finally the product was dried for use.

[0038] Example 2

[0039] Preparation method of two-dimensional vinyl covalent organic framework material (COF-205-Ir) catalyst:

[0040] Weigh 0.4 mmol of 2,2',6,6'-tetramethyl-4,4'-bipyridine, 0.8 mmol of 2,2'-bipyridine-5,5'-dicarbaldehyde, 0.04 mmol of benzoic acid and 0.6 mmol of benzoic anhydride in a glass tube and mix them evenly. Then, remove the air and water vapor in the system by means of ventilation and seal the tube under vacuum conditions. -1 The temperature was raised to 160°C at a rate of 1:0.5 and kept warm for 72 hours. After the reaction, the product was collected, ground and added with an appropriate amount of anhydrous ethanol and 1.0M NaOH solution in a ratio of 1:0.5, soaked for 24 hours to remove impurities, and the solid was taken out. Then, an appropriate amount of anhydrous ethanol and acetone in a ratio of 1:1 was added and soaked for 3 hours. The solution was changed and washed three times. The washed product was ground at high speed for 1 hour and dried under vacuum. Take 20 mg of the prepared two-dimensional vinyl covalent organic framework material (COF-205), add 10 mL of 0.5 mg / mL IrCl3 solution, mix evenly by ultrasonication, and keep warm at 25°C for 12 hours for loading. After the loading is completed, add an appropriate amount of a mixed solution of water and anhydrous ethanol to collect and wash the product, and finally dry the product for use.

[0041] Example 3

[0042] Preparation method of two-dimensional vinyl covalent organic framework material (COF-205-Fe) catalyst:

[0043] Weigh 0.4 mmol of 2,2',6,6'-tetramethyl-4,4'-bipyridine, 0.8 mmol of 2,2'-bipyridine-5,5'-dicarbaldehyde, 0.07 mmol of benzoic acid and 0.8 mmol of benzoic anhydride in a glass tube and mix them evenly. Then, remove the air and water vapor in the system by means of ventilation and seal the tube under vacuum conditions. -1 The temperature was raised to 180°C at a rate and kept warm for 72h. After the reaction, the product was collected, ground and added with an appropriate amount of anhydrous methanol and 1.0M NaOH solution in a ratio of 1:0.5, soaked for 24h to remove impurities, and the solid was taken out. Then an appropriate amount of anhydrous methanol and acetone in a ratio of 1:1 was added and soaked for 3h. The solution was changed and washed 3 times. The washed product was ground at high speed for 1h and dried under vacuum. Take 20mg of the prepared two-dimensional vinyl covalent organic framework material (COF-205), add 10mL of 1mg / mL FeCl3 solution, mix evenly with ultrasound and precipitate at 2℃min -1 The temperature was raised to 50°C at a rate of 1000 ℃ and kept at this temperature for 6 hours for loading. After the loading was completed, a mixed solution of water and anhydrous ethanol was added to collect and wash the product, and finally the product was dried for use.

[0044] Example 4

[0045] Preparation method of two-dimensional vinyl covalent organic framework material (COF-205-Co) catalyst:

[0046] Weigh 0.4 mmol of 2,2',6,6'-tetramethyl-4,4'-bipyridine, 0.8 mmol of 2,2'-bipyridine-5,5'-dicarbaldehyde, 0.10 mmol of benzoic acid and 0.90 mmol of benzoic anhydride in a glass tube and mix them evenly. Then, remove the air and water vapor in the system by means of ventilation and seal the tube under vacuum conditions. -1 The temperature was raised to 200°C at a rate and kept warm for 72h. After the reaction, the product was collected, ground and added with an appropriate amount of anhydrous ethanol and 1.0M NaOH solution in a ratio of 1:2.5, soaked for 24h to remove impurities, and the solid was taken out. Then an appropriate amount of anhydrous ethanol and tetrahydrofuran in a ratio of 1:0.5 was added and soaked for 3h. The solution was changed and washed 3 times. The washed product was ground at high speed for 1h and dried under vacuum. Take 20mg of the prepared two-dimensional vinyl covalent organic framework material (COF-205), add 10mL of 2mg / mL Co Cl3 solution, mix evenly with ultrasound and simmer at 2℃min -1The temperature was raised to 60°C at a rate of 1000 nm and kept at this temperature for 12 hours for loading. After loading, a mixed solution of water and anhydrous ethanol was added to collect and wash the product, and finally the product was dried for use.

[0047] Example 5

[0048] Preparation method of two-dimensional vinyl covalent organic framework material (COF-205-Ni) catalyst:

[0049] Weigh 0.4 mmol of 2,2',6,6'-tetramethyl-4,4'-bipyridine, 0.8 mmol of 2,2'-bipyridine-5,5'-dicarbaldehyde, 0.12 mmol of benzoic acid and 1.0 mmol of benzoic anhydride in a glass tube and mix them evenly. Then, remove the air and water vapor in the system by means of ventilation and seal the tube under vacuum conditions. -1 The temperature was raised to 180°C at a rate and kept warm for 72 hours. After the reaction, the product was collected, ground and added with an appropriate amount of anhydrous methanol and 1.0M NaOH solution in a 1:1 ratio, soaked for 24 hours to remove impurities, and the solid was taken out. Then an appropriate amount of anhydrous ethanol and tetrahydrofuran in a 1:1.5 ratio was added, soaked for 3 hours, and the solution was changed and washed 3 times. The washed product was ground at high speed for 1 hour and dried under vacuum. Take 20 mg of the prepared two-dimensional vinyl covalent organic framework material (COF-205), add 10 mL of 4 mg / mL Ni Cl3 solution, mix evenly with ultrasound, and precipitate at 2°C min -1 The temperature was raised to 90°C at a rate of 100°C and kept at this temperature for 24 hours for loading. After the loading was completed, a mixed solution of water and anhydrous ethanol was added to collect and wash the product, and finally the product was dried for use. (II) Analysis of the physical and chemical properties of the catalyst prepared in Example 1:

[0050] Related results such as Figure 1-6 shown.

[0051] Figure 1 The structural design of COF-205 before Ru loading is shown. Figure 1 It can be seen that the COF-205 prepared by the present invention is a two-dimensional porous structure constructed by four-connected ligands TMBP and two-connected ligands BPDA-py through carbon-carbon double bonds, with an sql topology.

[0052] Figure 2X-ray powder diffraction (XRD) analysis of COF-205 and COF-205-Ru reveals that the diffraction peaks at 4.59°, 6.45°, 9.15°, 13.76°, and 26.21° are attributed to the (110), (200), (220), (330), and (001) crystal planes of AA stacking, respectively. Furthermore, COF-205 still exhibits strong crystallinity after loading with Ru, indicating that the loading of Ru does not destroy the crystalline structure of the COF itself, demonstrating that the two-dimensional vinyl covalent organic framework material prepared by the present invention is a single compound with uniform chemical composition and structure.

[0053] Figure 3 COF-205 and COF-205-Ru 13 C solid-state NMR spectrum analysis. 13 C cross-polarization magic angle spinning (CP-MAS) solid-state NMR spectroscopy confirmed the formation of carbon-carbon double bonds in the COFs structure, which was consistent with the model molecule. 13 The C NMR spectra are in good agreement, indicating that the connection mode of COF-205 and COF-205-Ru is carbon-carbon double bond.

[0054] Figure 4 This is the nitrogen adsorption test analysis of COF-205-Ru. As can be seen from the figure, COF-205-Ru shows a higher adsorption platform, and its specific surface area is as high as 1200m 2 / g, indicating that COF-205-Ru has abundant active sites. In addition, the pore size analysis of COF-205-Ru shows that the pore size is about 1.5nm, which is consistent with Figure 1 The designed pore structure is consistent with that of COF-205-Ru, further proving the successful synthesis of COF-205-Ru.

[0055] Figure 5 This is the electron microscope characterization analysis diagram of COF-205-Ru. From the TEM diagram, it can be seen that the sample has a stacked morphology of a two-dimensional sheet structure, which is consistent with Figure 1 The two-dimensional layered structure is consistent with that shown.

[0056] EDX mapping was used to analyze the elements of COF-205-Ru. Figure 6 It can be seen that Ru, C and N elements are evenly distributed, and the Ru content is low. This is due to the monodispersity of Ru sites caused by the structural design of COF, which can improve the catalytic efficiency of active sites.

[0057] The OER performance of the catalyst prepared in Example 1 was tested and analyzed:

[0058] First, prepare the working electrode: mix the prepared nanomaterials and XC-72 carbon powder, add a mixed solution of isopropyl alcohol and 5% perfluorosulfonic acid (volume ratio of 49 / 1), and ultrasonically homogenize to form an ink-like state. Then use a microsyringe to draw a fixed volume of ink, add it dropwise to the glassy carbon electrode, and let it dry naturally before use.

[0059] The catalytic performance of the electrocatalyst was evaluated in a 0.5 M H2SO4 solution using a three-electrode system. In the oxygen evolution reaction (OER) test, the catalyst was first activated and cyclic voltammetry was used to activate the catalyst until it stabilized. Then, the potential range was 1.22 V to 1.72 V (vs. RHE) at a scan rate of 10 mV s -1 The OER test was performed at a speed of 1600 rpm. For the OER stability test, the potential range was 1.22 V to 1.72 V (vs. RHE) at a scan rate of 100 mV s -1 Cyclic voltammetry scans (CVs) were performed at a rate of , and after scanning 1000 cycles, an OER test was performed. The test method and setting parameters were consistent with those of the first test.

[0060] The OER test results are as follows:

[0061] Before the OER test, the catalyst was activated and then tested by cyclic voltammetry in an Ar-saturated 0.5 M H2SO4 solution. Figure 7 The OER polarization curves of COF-205-Ru / C, COF-205 / C, and commercial RuO2 / C were obtained at a scan rate of 10 mV s. -1 , speed is 1600 rpm -1 , the potential range is 1.22V~1.72V. When the current density is 10mAcm -2 When the OER overpotentials of COF-205-Ru / C and commercial RuO2 / C were 214mV and 320mV, respectively, COF-205 / C showed almost no OER activity, while the OER activity of COF-205-Ru / C was much higher than that of COF-205 / C and commercial RuO2 / C. The corresponding TS values, slopes of COF-205-Ru / C and commercial RuO2 / C were 98.0mV dec. -1 and 186mV dec -1 The results once again show that COF-205-Ru / C has a faster OER catalytic reaction rate.

[0062] We then explored the acidic OER stability of COF-205-Ru / C using the ADT test method. The test system was an Ar-saturated 0.5 M H2SO4 solution. The catalyst was first placed in an operating potential range of 1.22 V to 1.72 V and cyclic voltammetry was used for cyclic sweeps. After 1000 cycles of CV, the steady-state polarization curve of OER was tested and the polarization curve after stabilization was compared with the polarization curve before stabilization. The results are shown in Figure 2. Figure 8 As shown in the figure, it can be seen that the polarization curve after cycling stability has almost no activity decrease compared with the initial polarization curve, and the limiting current density has not changed significantly, indicating the excellent structural stability of COF-205-Ru in the acidic OER electrocatalytic process.

[0063] The acidic OER test results of COF-205-Ru indicate that the high activity of COF-205-Ru is primarily due to the material's structure. The structural design of the catalyst surface, a two-dimensional ultrathin nanosheet, evenly anchors monodisperse Ru sites, exposing more effective active sites. Furthermore, the formation of carbon-carbon double bonds and strong Ru-N interactions prevent the collapse of the framework and dissolution of Ru species during the OER process. This improves the energy barrier of the rate-determining step of the OER reaction through d-π electron interactions, thereby enhancing catalytic activity.

[0064] In summary, the present invention provides a two-dimensional vinyl covalent organic framework material catalyst. A two-dimensional vinyl covalent organic framework material OER catalyst is obtained by a Knoevenagel condensation synthesis method under sealed tube conditions. Highly stable, low-metal-loaded COFs materials are used to prepare efficient acidic OER catalysts. The π conjugated system of the vinyl COFs themselves ensures the high conductivity of the material, and the connection mode of the carbon-carbon double bond ensures long-term catalytic stability, which is suitable for commercial mass production. The preparation and synthesis of the two-dimensional vinyl covalent organic framework material catalyst provided by the present invention is conducive to increasing the number and density of catalytic active sites, reducing the dependence on traditional iridium-based catalysts, greatly improving the acidic OER activity, and having huge application prospects. Specifically, the present invention adopts a vinyl COF material (COF-205) synthesized by TMBP and BPDA-py as a substrate, and ruthenium chloride as a ruthenium source to prepare a two-dimensional vinyl covalent organic framework material OER catalyst COF-205-Ru. The construction of carbon-carbon double bonds and strong Ru-N interactions prevent the collapse of the framework and the dissolution of Ru species during the OER process, improving the energy barrier of the rate-determining step of the OER reaction through d-π electron interactions, thereby enhancing the catalytic activity and stability.

[0065] The X-ray powder diffraction patterns (XRD) of COF-205-Ir, COF-205-Fe, COF-205-Co and COF-205-Ni prepared in Examples 2-5 are shown in FIG. Figure 9 As shown in the figure, it can be seen that the diffraction peaks at 4.59°, 6.45°, 9.15°, 13.76° and 26.21° are respectively attributed to the (110), (200), (220), (330) and (001) crystal planes of AA stacking. In addition, COF-205 still shows strong crystallinity after loading any one of Ru, Ir, Pd, Pt, Rh, Ni, Co and Fe, indicating that the loading of any one of Ru, Ir, Pd, Pt, Rh, Ni, Co and Fe will not destroy the crystalline structure of COF itself, indicating that the two-dimensional vinyl covalent organic framework material prepared by the present invention is a single compound with uniform chemical composition and structure.

[0066] It should be noted that those skilled in the art should understand that the metal source can also be an iridium source, a palladium source, a rhodium source, an iron source, a nickel source, a cobalt source, etc., which are not exhaustively listed in the embodiments of the present invention. Through the preparation method provided by the present invention, two-dimensional vinyl covalent organic framework material catalysts such as COF-205-Ir, COF-205-Pd, COF-205-Pt, COF-205-Rh, COF-205-Fe, COF-205-Co and COF-205-Ni can be successfully prepared, and exhibit high catalytic activity.

[0067] The above description is only a preferred embodiment of the present invention, which certainly cannot be used to limit the scope of rights of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and changes can be made without departing from the principles of the present invention. These improvements and changes are also considered to be within the scope of protection of the present invention.

Claims

1. A method for preparing a two-dimensional vinyl covalent organic framework material, characterized in that: A two-dimensional vinyl covalent organic framework material is prepared by a Knoevenagel reaction under sealed tube conditions, comprising the following steps: uniformly mixing 2,2',6,6'-tetramethyl-4,4'-bipyridine, 2,2'-bipyridine-5,5'-dicarboxaldehyde, benzoic acid, and benzoic anhydride, and reacting them under vacuum conditions at 160-200°C; activating the reaction product and then immersing it in a solution containing a metal salt for loading; The solvent in the solution containing the metal salt is water, or a mixed solvent consisting of water and any one of methanol, ethanol, and tetrahydrofuran; the metal salt is any one of ruthenium chloride, iridium chloride, palladium chloride, rhodium chloride, chloroplatinic acid, ferric chloride, ferric nitrate, cobalt chloride, cobalt nitrate, nickel chloride, and nickel nitrate.

2. The method for preparing a two-dimensional vinyl covalent organic framework material according to claim 1, wherein: The molar ratio of the 2,2',6,6'-tetramethyl-4,4'-bipyridine, 2,2'-bipyridine-5,5'-dicarbaldehyde, benzoic acid and benzoic anhydride is 1:(1.5-2.5):(0.1-0.3):(1.5-2.5).

3. The method for preparing a two-dimensional vinyl covalent organic framework material according to claim 1, wherein: The activation step comprises: grinding the product collected after the reaction is completed and adding it to a mixed solution of anhydrous methanol or anhydrous ethanol and 1.0 M NaOH solution in a volume ratio of 1: (0.5-1.5) to soak and remove impurities; then adding the product to a mixed solution of anhydrous methanol or anhydrous ethanol and acetone or tetrahydrofuran in a volume ratio of 1: (0.5-1.5) to wash.

4. The method for preparing a two-dimensional vinyl covalent organic framework material according to claim 1, wherein: The concentration of the metal salt-containing solution is 0.5-4 mg / mL; the mass ratio of the vinyl covalent organic framework to the metal salt is 4:1-1:

2.

5. The method for preparing a two-dimensional vinyl covalent organic framework material according to claim 1, wherein: The load is uniformly mixed by ultrasound, the load temperature is 25-90° C., and the temperature is kept for 6-24 hours.

6. A two-dimensional vinyl covalent organic framework material, characterized by: The method is prepared according to any one of claims 1 to 5.

7. Use of the two-dimensional vinyl covalent organic framework material according to claim 6, characterized in that: The two-dimensional vinyl covalent organic framework material is used as a catalyst in an acidic oxygen evolution reaction.

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