Method for controllably growing sp2 carbon conjugated 2D COFs film on various substrates

Abstract

The invention discloses a preparation method of an sp2-carbon conjugated two-dimensional covalent organic framework (2D sp2C-COFs) film suitable for various substrates. Polydopamine (PDA) is used as a modification layer to assist in synthesizing the high-quality two-dimensional sp2C-COFs film on any substrate (ITO, a silicon wafer, quartz, a polytetrafluoroethylene tube and the like). According to the method, a firm PDA layer is formed on the surface of a substrate through oxidation auto-polymerization of dopamine, a large number of amino groups exist on the surface of PDA, covalent bond connection with a monomer with an aldehyde group can be formed through a Schiff base reaction, and then a high-quality 2D sp2C-COFs film is formed on the surface of the substrate through an aldol condensation reaction. The preparation method is simple, convenient to operate and high in universality, high-quality 2D sp2C-COFs films with different structures can be synthesized on various substrates, and the prepared material has efficient photon-generated carrier separation and transmission capacity.

Description

Technical Field

[0001] The present invention relates to the field of nanomaterial preparation, and in particular to a method for controllably growing high-quality sp on any substrate by modifying polydopamine as an intermediate layer. 2 Carbon conjugated two-dimensional covalent organic framework (2D sp 2 Preparation method of C-COFs) film. Background Art

[0002] sp 2 Carbon conjugated two-dimensional covalent organic framework (2D sp 2 C-COFs) are a new type of crystalline organic porous polymers with characteristics such as light weight, good stability, and high planar conjugation, which are conducive to charge delocalization and transmission. Therefore, they have outstanding application potential in optoelectronic devices and photo / electrocatalysis. Compared with traditional 2D COFs connected by imine bonds or borate bonds, 2D sp 2 C-COFs have better in-plane π-conjugated structure and high chemical stability, thus having better photoelectrochemical properties. In addition, the regular pore structure can provide good catalytic active sites, high specific surface area and porosity, which can promote the diffusion and transport of reactants and products.

[0003] However, the 2D sp 2 C-COFs exist in the form of powders, and thin-film devices can generally only be prepared by vacuum filtration or dispersed drop coating. They have defects such as loose stacking, poor controllability of the number of layers, irregular orientation, uneven surface, and weak interaction with the substrate, which are not conducive to the in-plane charge transfer and corresponding functions of two-dimensional materials. Secondly, the particle morphology of COF powder makes it difficult to fully expose its internal active sites, resulting in a decrease in the effective utilization rate of the material. Therefore, large-area, high-quality 2D sp 2 The preparation of C-COFs thin film materials is a difficult problem that needs to be solved urgently. Summary of the invention

[0004] In view of the above problems, the object of the present invention is to provide a method for growing high-quality sp 2 Carbon conjugated two-dimensional covalent organic framework (2Dsp 2 C-COFs) thin films.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] The present invention proposes placing a substrate with a PDA layer on a 2D sp 2 In the solution of C-COFs precursor, the strong adhesion between the PDA layer and the substrate, as well as the abundant amino groups on PDA and 2D sp2 The C-COFs aldehyde precursor undergoes a Schiff base reaction to make 2Dsp 2 The C-COFs aldehyde precursor molecules are adsorbed and evenly distributed on the substrate surface through covalent bonds. Subsequently, the aldehyde monomers and the monomers with activated (methylene) groups react under certain conditions through aldol condensation to form high-quality 2D sp 2 C-COFs thin films.

[0007] The preparation method comprises the following steps:

[0008] Step 1: Pre-treat the substrate

[0009] Clean the substrate materials (such as quartz wafers, silicon wafers, ITO, etc.). For quartz wafers and ITO substrates, immerse them in a mixed solution of ethanol and water = 1:1, and ultrasonicate for 30 minutes, repeat 3 times. For silicon wafer substrates, ultrasonicate for 10 minutes in deionized water, ethanol, and acetone, repeat 3 times, blow dry with N2, immerse in a fresh piranha solution (hydrogen peroxide: concentrated sulfuric acid = 3:7) for 30 minutes, then take it out and ultrasonicate for 10 minutes in deionized water, ethanol, and acetone, repeat 3 times, and blow dry with N2.

[0010] Step 2: Growing a PDA layer on the substrate

[0011] Weigh tris(hydroxymethyl)aminomethane (Tris) and dissolve it in deionized water. Add hydrochloric acid to adjust the pH to alkaline to a concentration of 5-6×10 -3 mol / L Tris buffer, then dissolve dopamine hydrochloride in Tris buffer, then stick the substrate pretreated in step 1 to the bottle wall with tape, immerse it in dopamine solution, stir the solution at 300-500r / min, and form a uniform and firm PDA film on the surface of the substrate through self-polymerization of dopamine in an alkaline environment. Take it out and wash it with ethanol and deionized water for 3 times, and blow it dry with N2.

[0012] Step 3: Growth of sp on substrate / PDA layer 2 C-COFs thin films

[0013] The substrate with PDA grown on the surface is placed on the 2D sp 2 In the C-COF reaction system, the system includes 2D sp 2 The two types of monomers with side chain aldehyde groups and activated (methylene) groups required for the synthesis of C-COFs, as well as catalysts, solvents, etc., are ultrasonicated for a period of time, then quickly frozen in a liquid nitrogen bath and vacuum sealed.

[0014] Step 4: Heat the reaction at a certain temperature, and after the reaction is completed, treat it with an organic solvent to obtain 2Dsp deposited and grown on the substrate. 2C-COF thin films.

[0015] Furthermore, in step 2, the preparation method of Tris buffer is to weigh 600-700 mg of tris(hydroxymethyl)aminomethane and dissolve it in 1-1.5 L of deionized water, and add hydrochloric acid to adjust the pH to 8.5-8.8.

[0016] Furthermore, in step 2, the dopamine hydrochloride solution is prepared by weighing 10-20 mg of dopamine hydrochloride and dissolving it in 20-40 ml of Tris buffer.

[0017] Furthermore, in step three, we can control the thickness of the COF film by changing the concentration of the monomer.

[0018] Furthermore, in step 3, 2D sp 2 The C-COF reaction system requires ultrasound for 15-30 min.

[0019] Furthermore, in step three, the test tube is placed in a 77K liquid nitrogen bath for quick freezing for 5-10 minutes.

[0020] Furthermore, in step three, the vacuum treatment time is 5-10 minutes.

[0021] Furthermore, in step three, the polymerization reaction is carried out at 120-160° C. for 72 hours.

[0022] Furthermore, in step 4, the solvents used for post-treatment are ethanol, tetrahydrofuran, methanol, and dichloromethane, which are washed 3 times (3×10 ml) respectively, and the vacuum drying temperature is 40-60° C. and the drying time is 12-24 h.

[0023] The present invention proposes to grow sp on any substrate 2 Carbon conjugated two-dimensional covalent organic framework (sp 2 Using the adhesion and intermolecular interaction of the PDA layer, a dense and uniform COF film is formed on the substrate.

[0024] The beneficial effects of the present invention are as follows:

[0025] The present invention utilizes the self-polymerization reaction of dopamine to form a uniform and stable PDA layer on the substrate for the first time, thereby inducing 2D sp 2 C-COFs thin film growth realizes 2D sp 2 Efficient preparation of C-COFs thin films.

[0026] Due to the strong binding ability of PDA to any substrate, the method provided by the present invention can grow 2D sp2C-COFs thin films on any substrate.

[0027] The present invention has high universality and can realize a variety of different structures of 2D sp 2 Growth of C-COFs thin films.

[0028] By changing the 2D sp 2 The concentration of C-COFs precursors is achieved by the present invention with different thickness 2D sp 2 Controllable growth of C-COFs thin films.

[0029] Since PDA is closely related to the substrate and 2D sp 2 Due to the strong interaction between C-COFs films and excellent hole transport ability, the resulting material has efficient photogenerated carrier separation and transport capabilities. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 For the preparation of 2D sp 2 Schematic diagram of the reaction of C-COFs film.

[0031] Figure 2 This is the reaction formula of the TFPT-PSTMP COF film prepared in Example 1.

[0032] Figure 3 This is a scanning electron microscope (SEM) image of the TFPT-PSTMP COF film grown on a silicon wafer prepared in Example 1.

[0033] Figure 4 This is the Fourier transform infrared spectrum (FT-IR) of the TFPT-PSTMP COF film prepared in Example 1.

[0034] Figure 5 This is the X-ray diffraction (XRD) pattern of the TFPT-PSTMP COF prepared in Example 1.

[0035] Figure 6 This is the Raman spectrum of the TFPT-PSTMP COF film prepared in Example 1.

[0036] Figure 7 These are SEM images of the TFPT-PSTMP COF films grown on silicon wafers, ITO wafers, and quartz wafers prepared in Example 2.

[0037] Figure 8 This is a picture of the TFPT-PSTMP COF film grown on a polytetrafluoroethylene tube prepared in Example 3.

[0038] Fig. 9 Atomic force microscope (AFM) images of TFPT-PSTMP COF films grown at different concentrations prepared in Example 4.

[0039] Fig.10 This is the reaction formula for the TMT-TPACOF thin film grown on a silicon wafer substrate in Example 5.

[0040] Fig.11 This is the SEM image of the TMT-TPACOF film grown on the silicon wafer substrate in Example 5.

[0041] Fig.12 This is the FT-IR image of the TMT-TPACOF thin film grown on the silicon wafer substrate in Example 5.

[0042] Fig.13 This is the SEM image of the TFPT-PSTMP COF film prepared on the silicon wafer substrate without PDA modification in Control Example 1.

[0043] Fig.14 This is the time-current curve (IT test) of the TFPT-PSTMP COF film prepared in Application Example 1. Specific implementation plan

[0044] In order to more clearly illustrate the present invention, the present invention is further described below in conjunction with preferred embodiments and accompanying drawings. Similar components in the accompanying drawings are represented by the same reference numerals. It should be understood by those skilled in the art that the content specifically described below is illustrative rather than restrictive, and should not be used to limit the scope of protection of the present invention.

[0045] Embodiment 1:

[0046] TFPT-PSTMP COF thin film (structural formula: Figure 2 As shown), first, the silicon wafer was ultrasonically treated in deionized water, ethanol, and acetone for 10 minutes respectively, repeated 3 times, and then dried with N2. Then, it was immersed in a freshly prepared piranha solution (hydrogen peroxide: concentrated sulfuric acid = 3:7) for 30 minutes. Then, it was taken out and ultrasonically treated in deionized water, ethanol, and acetone for 10 minutes respectively, repeated 3 times, and the silicon wafer was taken out and dried with N2.

[0047] Weigh 607 mg of tris(hydroxymethyl)aminomethane and dissolve it in 1000 ml of deionized water. Add hydrochloric acid to adjust the pH to 8.77 to obtain a concentration of 5×10 -3 mol / L Tris buffer, then weigh 16 mg of dopamine hydrochloride and dissolve it in 40 ml of Tris buffer, stick the silicon wafer to the bottle wall with tape, stir the solution at 300 r / min for 24 h to obtain silicon wafer / PDA, take it out and wash it with water and ethanol three times in sequence, and then blow it dry with N2.

[0048] Weigh 24.3 mg of N-(3-sulfopropyl)-2,4,6-(trimethyl)pyridine (PSTMP), 39.4 mg of 4,4',4"-(1,3,5-triazine-2,4,6-triyl)tribenzaldehyde (TFPT), and 73.3 mg of 4-dimethylaminopyridine and dissolve them in 0.7 ml of deionized water. 2 After the C-COFs precursor solution was ultrasonicated for 10 min, the silicon wafer / PDA substrate was placed at the bottom of the tube, and the tube was placed in a 77K liquid nitrogen bath for quick freezing, vacuum sealed, and heated at 160°C for 72 h. After the reaction, the substrate was taken out, washed with deionized water and ethanol in turn, and dried with N2 to obtain a 2D sp 2 C-COF thin films.

[0049] Figure 3 The SEM image of the TFPT-PSTMP COF film grown on a silicon wafer shows that the TFPT-PSTMP COF film layer is continuous and uniform. The Fourier infrared spectrum of the TFPT-PSTMP COF film shows that the -1 The characteristic peak of C=C indicates the occurrence of polymerization reaction ( Figure 4 ). The Raman spectrum of TFPT-PSTMP COF film can also be obtained at 1601cm -1 The characteristic peak of C=C appears at Figure 6 ).

[0050] Embodiment 2:

[0051] TFPT-PSTMP COF thin films were grown on ITO, quartz wafers, and calcium fluoride windows. The substrates were first placed in 10 ml of ethanol and 10 ml of deionized water and ultrasonicated for 10 min. After repeating this process three times, the substrates were taken out and dried with N2.

[0052] Weigh 607 mg of tris(hydroxymethyl)aminomethane and dissolve it in 1000 ml of deionized water. Add hydrochloric acid to adjust the pH to 8.77 to obtain a concentration of 5×10 -3 mol / L Tris buffer, then weigh 16 mg of dopamine hydrochloride and dissolve it in 40 ml of Tris buffer, stick the silicon wafer to the bottle wall with tape, stir the solution at 300 r / min for 24 h to obtain the substrate / PDA, take it out and wash it with water and ethanol three times in sequence, and then blow it dry with N2.

[0053] Weigh 24.3 mg of N-(3-sulfopropyl)-2,4,6-(trimethyl)pyridine, 39.4 mg of 4,4',4"-(1,3,5-triazine-2,4,6-triyl)tribenzaldehyde, and 73.3 mg of 4-dimethylaminopyridine and dissolve them in 0.7 ml of deionized water.2 After the C-COFs precursor solution was ultrasonicated for 10 minutes, the substrate / PDA substrate was placed at the bottom of the tube, and the test tube was placed in a 77K liquid nitrogen bath for quick freezing, vacuum sealed, and heated at 160°C for 72 hours. After the reaction, the substrate was taken out, washed with deionized water and ethanol in turn, and dried with N2 to obtain 2Dsp deposited and grown on the substrate. 2 C-COF film. Figure 7 As shown, the prepared 2Dsp 2 The surface of C-COFs film is dense, uniform and continuous.

[0054] Embodiment 3:

[0055] The TFPT-PSTMP COF film was grown on the polytetrafluoroethylene tube. First, the polytetrafluoroethylene tube was placed in 10 ml of ethanol and 10 ml of deionized water and ultrasonicated for 10 min. After repeating this three times, the polytetrafluoroethylene tube was taken out and dried with N2.

[0056] Weigh 607 mg of tris(hydroxymethyl)aminomethane and dissolve it in 1000 ml of deionized water. Add hydrochloric acid to adjust the pH to 8.77 to obtain a concentration of 5×10 -3 mol / L Tris buffer, then weigh 16 mg of dopamine hydrochloride and dissolve it in 40 ml of Tris buffer, stick the polytetrafluoroethylene tube to the bottle wall with tape, stir the solution at 300 r / min for 24 h to obtain the polytetrafluoroethylene tube / PDA, take it out and wash it with water and ethanol three times in sequence, and then blow it dry with N2.

[0057] Weigh 24.3 mg of N-(3-sulfopropyl)-2,4,6-(trimethyl)pyridine, 39.4 mg of 4,4',4"-(1,3,5-triazine-2,4,6-triyl)tribenzaldehyde, and 73.3 mg of 4-dimethylaminopyridine and dissolve them in 0.7 ml of deionized water. After ultrasonicating the prepared COF precursor solution for 10 minutes, the polytetrafluoroethylene tube / PDA was placed at the bottom of the tube, and the test tube was placed in a 77K liquid nitrogen bath for quick freezing, vacuum sealed, and reacted at 160°C for 72 hours. After the reaction, the wafer was taken out, washed with deionized water and ethanol, and then dried with N2 to obtain a 2D sp deposited and grown on the substrate. 2 C-COF film. Figure 8 As shown, the prepared 2D sp 2 The surface of C-COFs film is continuous.

[0058] Embodiment 4:

[0059] TFPT-PSTMP COF films of different thicknesses can be grown on silicon wafers (when C PSTMP=0.071, 0.047, 0.026, 0.024 mol / L), firstly, ultrasonically soak the silicon wafer in deionized water, ethanol, and acetone for 10 min respectively, repeat 3 times, blow dry with N2, and then immerse it in a freshly prepared piranha solution (hydrogen peroxide: concentrated sulfuric acid = 3:7) for 30 min. Then, take it out and ultrasonically soak it in deionized water, ethanol, and acetone for 10 min respectively, repeat 3 times, take out the silicon wafer and blow dry it with N2.

[0060] Weigh 607 mg of tris(hydroxymethyl)aminomethane and dissolve it in 1000 ml of deionized water. Add hydrochloric acid to adjust the pH to 8.77 to obtain a concentration of 5×10 -3 mol / L Tris buffer, then weigh 16 mg of dopamine hydrochloride and dissolve it in 40 ml of Tris buffer, stick the silicon wafer to the bottle wall with tape, stir the solution at 300 r / min for 24 h to obtain silicon wafer / PDA, take it out and wash it with water and ethanol three times in sequence, and then blow it dry with N2.

[0061] Weigh the corresponding amount of N-(3-sulfopropyl)-2,4,6-(trimethyl)pyridine, 4,4',4"-(1,3,5-triazine-2,4,6-triyl)tribenzaldehyde, and 4-dimethylaminopyridine and dissolve them in deionized water. 2 After the C-COFs precursor solution was ultrasonicated for 10 min, the silicon wafer / PDA substrate was placed at the bottom of the tube, and the tube was placed in a 77K liquid nitrogen bath for quick freezing, vacuum sealed, and heated at 160°C for 72 h. After the reaction, the substrate was removed, washed with deionized water and ethanol in turn, and then dried with N2. 2 The concentration of C-COFs precursors is achieved by the present invention with different thickness 2D sp 2 Controllable Growth of C-COFs Thin Films ( Fig. 9 ).

[0062] Example 5

[0063] TMT-TPACOF thin film (structure formula: Fig.10 As shown), first, the silicon wafer was ultrasonically treated in deionized water, ethanol, and acetone for 10 minutes respectively, repeated 3 times, and then dried with N2. Then, it was immersed in a freshly prepared piranha solution (hydrogen peroxide: concentrated sulfuric acid = 3:7) for 30 minutes. Then, it was taken out and ultrasonically treated in deionized water, ethanol, and acetone for 10 minutes respectively, repeated 3 times, and the silicon wafer was taken out and dried with N2.

[0064] 16 mg of dopamine hydrochloride was weighed and dissolved in 40 ml of Tris buffer prepared in Example 1. The silicon wafer was taped to the bottle wall and the solution was stirred at 300 r / min for 24 h to obtain silicon wafer / PDA. The silicon wafer / PDA was taken out and washed with water and ethanol three times in sequence and then dried with N2.

[0065] Weigh 61.58 mg of 1,3,5-trimethyltriazine, 100.6 mg of terephthalaldehyde, and 84.15 mg of potassium hydroxide and dissolve them in 3.5 ml of n-butanol and 1.5 ml of o-dichlorobenzene solution. 2 After the C-COFs precursor solution was ultrasonicated for 10 minutes, the silicon wafer / PDA substrate was placed at the bottom of the tube, and the test tube was placed in a 77K liquid nitrogen bath for quick freezing, vacuum sealed, and heated at 120°C for 72 hours. After the reaction, the substrate was taken out, washed with deionized water and ethanol in turn, and dried with N2 to obtain a 2D sp 2 C-COF film. Fig.11 As shown in the figure, the surface of the prepared COF film is uniform and continuous. From the Fourier infrared spectrum of the TMT-TPACOF film, it is found that the -1 The characteristic peak of C=C is shown at Fig.12 ).

[0066] Comparative Example 1

[0067] To grow TFPT-PSTMP COF thin films on quartz wafers, the quartz wafers were first placed in 10 ml of ethanol and 10 ml of deionized water and ultrasonicated for 10 min. After repeating this process three times, the quartz wafers were taken out and dried with N2. 2 To determine the decisive role of the growth of C-COFs thin films, we wrapped a 0.5 cm wide dry tape in the middle of a 1.5 cm × 1.5 cm quartz sheet.

[0068] Weigh 607 mg of tris(hydroxymethyl)aminomethane and dissolve it in 1000 ml of deionized water. Add hydrochloric acid to adjust the pH to 8.77 to obtain a concentration of 5×10 -3 mol / L Tris buffer, then weigh 16 mg of dopamine hydrochloride and dissolve it in 40 ml of Tris buffer, stick the quartz plate to the bottle wall with tape, stir the solution at 300 r / min for 24 h to obtain the quartz plate / PDA, take it out and wash it with water and ethanol three times in sequence, and then blow dry it with N2.

[0069] Weigh 24.3 mg of N-(3-sulfopropyl)-2,4,6-(trimethyl)pyridine, 39.4 mg of 4,4',4"-(1,3,5-triazine-2,4,6-triyl)tribenzaldehyde, and 73.3 mg of 4-dimethylaminopyridine and dissolve them in 0.7 ml of deionized water. 2After the C-COFs precursor solution was ultrasonicated for 10 min, the quartz sheet / PDA substrate was placed at the bottom of the tube with the PDA layer facing down. The test tube was placed in a 77K liquid nitrogen bath for quick freezing, vacuum sealed, and heated at 160°C for 72 h. After the reaction, the substrate was removed, washed with deionized water and ethanol in turn, and dried with N2 to obtain a 2D sp 2 C-COF film. Fig.13 As shown in a, the SEM image shows that when there is no PDA layer, the COF film is discontinuous and the surface is rough, while when there is a PDA layer on the substrate surface, the 2D sp 2 C-COFs films grow uniformly and densely (13b).

[0070] Application Example 1

[0071] Photoelectric performance test was carried out in CHI 660E three-electrode system, the TFPT-PSTMP COF film prepared in Example 2 was used as working electrode, Pt as counter electrode, Ag / AgCl as reference electrode, 0.2M Na2SO4 solution as electrolyte, placed under 400nm LED light, and kept at room temperature with a fan, and time-current curve test was carried out at -0.4V, with sampling interval of 0.1s and running time of 100s. Fig.14 As shown, the photocurrent density can reach 38μA / cm -2 When the COF powder dispersion was dropped on the ITO substrate for testing, the photocurrent density was only 6 μA / cm -2 , which proves that due to the interaction between PDA and substrate and 2D sp 2 Due to the strong interaction between C-COFs films and excellent hole transport ability, the resulting materials have efficient photogenerated carrier separation and transport capabilities, thus having potential applications in the field of photo / photoelectrocatalysis.

[0072] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not limitations on the implementation methods of the present invention. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is impossible to list all the implementation methods here. All obvious changes or modifications derived from the technical solution of the present invention are still within the protection scope of the present invention.

Claims

1. A method for growing sp on any substrate 2 Carbon conjugated two-dimensional covalent organic framework (2D sp 2 C-COFs) thin film, characterized in that The method comprises the following steps: Step 1: Clean the substrate material to remove impurities on the surface and ensure that the substrate surface is clean and flat. Step 2: Weigh tris(hydroxymethyl)aminomethane (Tris) and dissolve it in deionized water, add hydrochloric acid to adjust the pH to alkaline to obtain Tris buffer, then dissolve dopamine hydrochloride in the Tris buffer, and then immerse the pretreated substrate in the dopamine solution, stir the solution, and form a uniform and firm PDA film on the substrate surface through the self-polymerization reaction of dopamine in an alkaline environment. Step 3: Place the substrate with PDA grown on the surface on a 2D sp 2 In the C-COF reaction system, the system includes 2Dsp 2 The two types of monomers with side chain aldehyde groups and activated (methylene) groups required for the synthesis of C-COFs, as well as catalysts, solvents, etc., are ultrasonicated for a period of time, then quickly frozen in a liquid nitrogen bath, and vacuum sealed. Step 4: Heat the reaction at a certain temperature, and after the reaction is completed, a 2D sp2C-COF film is deposited and grown on the substrate after post-treatment with a certain solvent.

2. The preparation method according to claim 1, characterized in that In step 1, the substrate includes ITO, silicon wafer, quartz wafer, calcium fluoride window, glass, polytetrafluoroethylene, etc.

3. The preparation method according to claim 1, characterized in that: In step 2, the pH range needs to be adjusted to 8.0-9.

0.

4. The preparation method according to claim 1, characterized in that: In step 2, the concentration of Tris buffer is 5-6×10 -3 mol / L, the stirring rate is controlled at 200-500r / min, and the sedimentation time is controlled at 30min-96h.

5. The preparation method according to claim 1, characterized in that: In step 3, the side chain aldehyde monomer is any one of the following: 4,4',4"-(1,3,5-triazine ring-2,4,6-triyl) tribenzaldehyde, terephthalaldehyde, biphenyl dicarboxaldehyde, trimesic acid, 1,4-dibromoterephthalaldehyde, trialdehyde phloroglucinol, 2,4,6-trihydroxybenzene-1,3,5-tricarbaldehyde, 2,5-dihydroxyterephthalaldehyde.

6. The preparation method according to claim 1, characterized in that: In step three, the monomer with an activated (methylene) group is any one of the following: (3-sulfopropyl)-2,4,6-(trimethyl)pyridine and 1,3,5-trimethyltriazine, N,4,6-trimethyl-1,3,5-triazine-2-amine, 4-isobutyl-6-methyl-1,3,5-triazine-2-amine, and 2-chloro-4,6-di-p-tolyl-1,3,5-triazine.

7. The preparation method according to claim 1, characterized in that: In step 3, the catalyst is at least one of the following: acetic acid, trifluoroacetic acid, 4-dimethylaminopyridine, sodium hydroxide, and potassium hydroxide.

8. The preparation method according to claim 1, characterized in that: In step 3, the organic solvent is any one or two of the following: deionized water, o-dichlorobenzene, n-butanol, mesitylene, 1,4-dioxane, N,N-dimethylformamide, and N,N-dimethylacetamide.

9. The preparation method according to claim 1, characterized in that: In step three, the ultrasonic treatment time is 30 minutes, the liquid nitrogen freezing time is 5-10 minutes, and the vacuum treatment time is 5-10 minutes.

10. The preparation method according to claim 1, characterized in that: In step 4, the heating reaction temperature is 120-160° C., and the heating reaction time is 72 h.

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