Covalent triazine framework derivatives, methods of making and use thereof in electrocatalytic oxygen reduction

Abstract

The application belongs to the technical field of organic framework materials, and specifically provides a covalent triazine framework derivative, a preparation method thereof and application of the covalent triazine framework derivative in electrocatalytic oxygen reduction, and the preparation method of the covalent triazine framework derivative comprises the following steps: 1) a fluorine-containing monomer is subjected to a polymerization reaction under the action of a catalyst to obtain CTF-3-2F; 2) the CTF-3-2F obtained in step 1) is subjected to a reaction with a pyridine monomer to obtain CTF-3-Apy, and the application is completed. The covalent triazine framework derivative prepared in the application has excellent crystallinity, super-high chemical stability, structure designability and excellent electrocatalytic oxygen reduction activity for hydrogen peroxide production.

Description

Technical Field

[0001] This application belongs to the field of organic framework materials technology, and in particular relates to a covalent triazine framework derivative, its preparation method and its application in electrocatalytic oxygen reduction. Background Technology

[0002] Covalent organic frameworks (COFs) are a new type of crystalline organic polymers. They are formed by the thermodynamic reversible polymerization of small organic molecules. Their topologically extended structures are periodic, with abundant pore structures and controllable pore sizes. The diversity of the polymerizing monomers enables structural diversity.

[0003] Catalysts are closely related to human production and daily life. Their historical origins can be traced back to ancient societies using them to produce alcoholic beverages. In today's mature industrial systems, they are involved in the manufacture of various chemicals and the solution of environmental problems. Copolymers (COFs) possess the potential to be excellent catalysts. Their functionalized units can be adjusted and replaced, their porosity is high and their pore size can be adjusted, and their extremely high specific surface area allows for effective contact between the catalyst sites and reactants. These advantages have led to increasing attention from researchers to the application of COFs in catalysis.

[0004] The oxygen reduction reaction (ORR) is a crucial reaction involved in the electrochemical energy conversion and green chemical production within green energy systems. For example, zinc-air batteries (ZABs) have become one of the representative sustainable systems due to their low cost, high safety, and high energy density. However, most previously reported ZABs involve strongly alkaline electrolytes, where four electrons (4e...) are... - The oxygen reduction reaction (ORR) occurs on an air electrode with the participation of H2O, but the kinetics of the air electrode are poor, requiring a complex and expensive catalyst system to accelerate this process. A two-electron (2e) catalyst system is used instead. - Redox chemistry offers an alternative solution for generating solid zinc peroxide (ZnO2) discharge products in the electrolyte. (The last sentence appears to be incomplete and possibly contains errors. It's unclear what "4e" refers to.) - Compared to traditional ZABs, this 2e-based - ZABs have fewer side effects, operate stably in air, have high zinc anode utilization, good positive electrode reversibility, and strong sustainability. Similar to other metal-air batteries containing peroxides, 2e - At the positive electrode of ZABs, a gas / liquid / solid three-phase reaction occurs simultaneously. Insoluble and insulating solid discharge products may block mass transfer channels and cover active sites. Accumulated products usually cause high overpotentials during charge and discharge.

[0005] Therefore, an ideal air cathode not only needs to achieve excellent efficiency in electrocatalytic oxygen reduction to produce H2O2, but also should have sufficient space to absorb the solid discharge products of ZnO2 and an efficient pathway for mass (oxygen and electrolyte) / electron transport. Covalent organic frameworks (COFs) have attracted much attention due to their porous crystal structure and high tunability. Currently, COFs are widely used in electrocatalysis, especially in oxygen evolution reaction, carbon dioxide reduction, and oxygen reduction reaction. However, their application in electrochemical reactions has not been thoroughly explored, mainly because the development of these COF systems as novel, efficient, and active electrochemical functional platforms still requires comprehensive regulation of the inherent electronic environment and charge transfer capabilities of the framework.

[0006] In response, technical personnel have conducted a series of research activities. For example, patent application CN115160579A discloses a two-dimensional covalent organic framework material for electrocatalytic oxygen reduction and its preparation method. COF-A is synthesized from 1,3,5-tris(4-aminophenyl)benzene and 2,5-dimethoxybenzene-1,4-dicarboxaldehyde as substrates via a Schiff base reaction solvothermal method. Then, COF-A is converted to COF-B via a Povarov reaction solvothermal method. The pre-designable and post-synthetic modification of this covalent organic framework can clearly introduce electrochemical active sites, and its unique porosity provides ion transport channels, resulting in high electrocatalytic oxygen reduction performance in the composite material.

[0007] For example, patent application CN117352755A discloses the application of nitrogen / chlorine-doped covalent triazine framework polymers as non-metallic electrocatalysts for ORR reactions. CCTFs materials are synthesized using monomers containing imidazolium salts. These materials are porous polymers with uniform dual heteroatom doping and high specific surface area. The preparation method is simple, environmentally friendly, and has high element utilization. They exhibit excellent ORR electrocatalytic performance, good stability, and resistance to methanol oxidation, thus making them suitable for use as ORR catalysts.

[0008] Besides the aforementioned covalent organic framework materials, covalent triazine frameworks (CTFs) constructed via aromatic triazine linkages possess unique characteristics such as excellent chemical and thermal stability, highly conjugated network structures, and abundant active triazine groups, effectively addressing current challenges in COF materials. Based on the unique properties of CTFs, targeted functionalization can effectively improve the activity and stability of electrocatalytic oxygen reduction to H₂O₂ production. Furthermore, the excellent electrochemical stability and uniform pore structure of CTFs facilitate the transport of solid-state discharge products and mass / electron transport. However, current CTF materials exhibit poor diversity, and research on functionalization is limited, posing significant challenges in the electrocatalytic oxygen reduction to hydrogen peroxide reaction. Summary of the Invention

[0009] To address the aforementioned issues and further improve the electrocatalytic oxygen reduction performance of CTFs, this application provides a covalent triazine framework derivative, its preparation method, and its application in electrocatalytic oxygen reduction.

[0010] This application first provides a method for preparing a covalent triazine framework derivative, comprising the following steps:

[0011] 1) Fluorine-containing monomers are polymerized under the action of a catalyst to obtain CTF-3-2F;

[0012] 2) Take the CTF-3-2F obtained in step 1) and react it with the pyridine monomer to obtain CTF-3-Apy.

[0013] Furthermore, in step 1), the fluorinated monomer is 2',5'-difluoro-[1,1':4',1-terphenyl]-4,4-dionitrile or 2',3',5',6'-tetrafluoro-[1,1':4',1-terphenyl]-4,4-dionitrile;

[0014] And / or, in step 1), the catalyst is a Lewis acid catalyst;

[0015] And / or, in step 1), the molar ratio of the fluorinated monomer to the catalyst is (0.2-1):(0.2-0.7).

[0016] Furthermore, the Lewis acid catalyst is one of trifluoromethanesulfonic acid, trifluoroacetic acid, hydrochloric acid, sulfuric acid, and acetic acid.

[0017] Furthermore, the polymerization reaction is carried out under sealed conditions with a temperature of 200-400℃ and a holding time of 10-20h.

[0018] Furthermore, the heat preservation reaction under sealed conditions involves placing the fluorine-containing monomer and catalyst inside a glass tube, melting and sealing the glass tube, and then carrying out the heat preservation reaction.

[0019] Furthermore, the glass tube has a length of 15-25cm and a radius of 5-10mm.

[0020] Furthermore, in step 2), the ratio of CTF-3-2F to pyridine monomer is (100-300) mg:(100-300) μL;

[0021] And / or, in step 2), the pyridine monomer is one of 2-aminopyridine, 3-aminopyridine, and 4-aminopyridine;

[0022] And / or, in step 2), the reaction temperature is 90-120℃ and the reaction time is 6-20h.

[0023] Furthermore, in step 2), the reaction is carried out in a solvent, which is one of DMSO, DMF, DMAC, DMC, sulfolane, acetonitrile, and tetrahydrofuran.

[0024] This application provides a covalent triazine framework derivative, which is prepared by the above-described method.

[0025] This application also provides the application of a covalent triazine framework derivative in electrocatalytic oxygen reduction. The covalent triazine framework derivative prepared by the above preparation method is used for electrocatalytic degradation of organic pollutants, metal-air batteries, electrocatalytic water splitting, and carbon dioxide reduction.

[0026] Compared with the prior art, this application has the following beneficial effects:

[0027] 1. This application first obtains a highly crystalline fluorinated CTF material. The stable chemical structure of the covalent triazine framework material itself provides assurance in electrocatalytic stability testing, and the presence of CF allows for subsequent functionalization modifications. Furthermore, by functionalizing the fluorinated CTF and introducing pyridine units within the framework, the internal chemical structure of the framework can be altered, thereby enabling the regulation of the electronic environment within the framework and exhibiting excellent electrocatalytic activity and selectivity.

[0028] 2. Compared to other fluorinated covalent triazine frameworks, the fluorinated covalent triazine framework obtained in this application exhibits superior crystallinity. Compared to other organic framework catalysts, the fluorinated covalent triazine framework material possesses extremely high chemical stability and structural designability. Through post-functionalization modification of the fluorinated covalent triazine framework material to introduce pyridine units, it exhibits excellent electrocatalytic oxygen reduction to hydrogen peroxide production activity. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the chemical structures of CTF-3-2F and CTF-3-Apy prepared in Example 3 of this application. The left side is CTF-3-2F and the right side is CTF-3-Apy.

[0030] Figure 2 This is an XRD pattern of CTF-3-2F prepared in Example 3 of this application.

[0031] Figure 3 This is a schematic SEM image of CTF-3-2F prepared in Example 3 of this application.

[0032] Figure 4 This is an FT-IR schematic diagram of CTF-3-2F and CTF-3-Apy prepared in Example 3 of this application.

[0033] Figure 5 This is a schematic diagram of the electrocatalytic oxygen reduction LSV test data of CTF-3-2F and CTF-3-Apy prepared in Example 3 of this application.

[0034] Figure 6 This is a schematic diagram of the electrocatalytic oxygen reduction selectivity test data of CTF-3-2F and CTF-3-Apy prepared in Example 3 of this application. Detailed Implementation

[0035] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0036] This application, based on extensive experimental research, explores the preparation of fluorine-containing covalent triazine framework derivatives and their application in electrocatalytic oxygen reduction. A highly crystalline fluorine-containing triazine covalent organic framework material was prepared by one-step polymerization and further functionalized by introducing highly active pyridine units into the framework, which significantly improved the electronic environment inside the framework and achieved efficient and stable electrocatalytic oxygen reduction to produce hydrogen peroxide.

[0037] Specifically, this application provides a method for preparing a covalent triazine framework derivative, comprising the following steps:

[0038] 1) Fluorine-containing monomers are polymerized under the action of a catalyst to obtain CTF-3-2F;

[0039] 2) Take the CTF-3-2F obtained in step 1) and react it with the pyridine monomer to obtain CTF-3-Apy.

[0040] A more preferred method for preparing covalent triazine framework derivatives includes the following steps:

[0041] 1) Preparation of covalent triazine frameworks using the classic tube-sealing method: A mixture of monomer (0.2-1 mmol) and Lewis acid catalyst (0.2-0.7 mmol) was added to a quartz glass tube 15-25 cm long and 5-10 mm in radius. The glass tube was then melt-sealed at high temperature. The sealed tube was then placed in a muffle furnace at 200-400 °C for 10-20 h. After the reaction, the quartz glass tube was cooled to room temperature and opened. The granular product was pulverized and soaked overnight in hydrochloric acid solution, then washed sequentially with deionized water, ethanol, DMF, and THF. After filtration, it was vacuum-dried at 100 °C for 12 h to obtain CTF-3-2F.

[0042] 2) Place 100-300 mg of CTF-3-2F obtained in step 1) into a round-bottom flask, add 20-60 mL of DMSO solution, and sonicate for 20-60 min. Then add 200 mg of potassium tert-butoxide and (100-300 μL) of pyridine monomers (2-aminopyridine, 3-aminopyridine, 4-aminopyridine). Reflux at 90-120 °C for 6-20 h. Wash successively with deionized water and ethanol. After filtration, vacuum dry at 100 °C for 12 h to obtain CTF-3-Apy.

[0043] Furthermore, in step 1), the fluorinated monomer is 2',5'-difluoro-[1,1':4',1-terphenyl]-4,4-dionitrile or 2',3',5',6'-tetrafluoro-[1,1':4',1-terphenyl]-4,4-dionitrile;

[0044] And / or, in step 1), the catalyst is a Lewis acid catalyst;

[0045] And / or, in step 1), the molar ratio of the fluorinated monomer to the catalyst is (0.2-1):(0.2-0.7).

[0046] In some specific embodiments, in step 1), the molar ratio of the fluorinated monomer to the catalyst can be 0.2:(0.2-0.7), 0.6:(0.2-0.7), or 1:(0.2-0.7). For example, the molar ratio of the fluorinated monomer to the catalyst can be 0.2:0.25, 0.2:0.25, 0.2:0.3, 0.2:0.35, 0.2:0.4, 0.2:0.45, 0.2:0.5, 0.2:0.55, 0.2:0.6, 0.2:0.65, 0.2:0.7, 0.3:0.25, 0.3:0.25, 0.3:0.3, 0.4:0.35, 0.4:0.45, 0.4:0.5, 0.4:0.55, or 0.4:0. 6, 0.4:0.65, 0.4:0.7, 0.5:0.25, 0.5:0.25, 0.5:0.3, 0.5:0.35, 0.5:0.4, 0.5:0.45, 0.5:0.55, 0.5:0.6, 0.5:0.65, 0.5:0.7, 0.6:0.25, 0.6:0.25, 0.6:0.3, 0.6:0.35, 0.6:0.4, 0.6:0.45, 0.6:0.5, 0.6:0.55, 0.6:0 0.65, 0.6:0.7, 0.7:0.25, 0.7:0.25, 0.7:0.3, 0.7:0.35, 0.7:0.4, 0.7:0.45, 0.7:0.5, 0.7:0.55, 0.7:0.6, 0.7:0.65, 0.8:0.25, 0.8:0.25, 0.8:0.3, 0.8:0.35, 0.8:0.4, 0.8:0.45, 0.8:0.5, 0.8:0.55, 0.8:0.6, 0.8: The preferred molar ratios for the fluorinated monomer to the catalyst are 0.65, 0.8:0.7, 0.9:0.25, 0.9:0.25, 0.9:0.3, 0.9:0.35, 0.9:0.4, 0.9:0.45, 0.9:0.5, 0.9:0.55, 0.9:0.6, 0.9:0.65, 0.9:0.7, 1:0.25, 1:0.25, 1:0.3, 1:0.35, 1:0.4, 1:0.45, 1:0.5, 1:0.55, 1:0.6, 1:0.65, and 1:0.7. More preferably, when the molar ratio of fluorinated monomer to catalyst is 0.4:0.3, 0.7:0.5, or 1:0.7, better experimental results can be obtained.

[0047] Furthermore, the Lewis acid catalyst is one of trifluoromethanesulfonic acid, trifluoroacetic acid, hydrochloric acid, sulfuric acid, and acetic acid.

[0048] Furthermore, the polymerization reaction is carried out under sealed conditions with a temperature of 200-400℃ and a holding time of 10-20h.

[0049] In some specific embodiments, the polymerization reaction is carried out under sealed and incubated conditions at temperatures of 200°C, 250°C, 300°C, 350°C, and 400°C. The incubation time can be 10h, 11h, 12h, 13h, 14h, 15h, 16h, 17h, 18h, 19h, or 20h. Generally, reaction temperatures of 200°C, 300°C, and 400°C, with incubation times of 10h, 15h, and 20h, yield better experimental results.

[0050] Furthermore, the heat preservation reaction under sealed conditions involves placing the fluorine-containing monomer and catalyst inside a glass tube, melting and sealing the glass tube, and then carrying out the heat preservation reaction.

[0051] Furthermore, the glass tube has a length of 15-25cm and a radius of 5-10mm.

[0052] Furthermore, in step 2), the ratio of CTF-3-2F to pyridine monomer is (100-300) mg:(100-300) μL;

[0053] And / or, in step 2), the pyridine monomer is one of 2-aminopyridine, 3-aminopyridine, and 4-aminopyridine;

[0054] And / or, in step 2), the reaction temperature is 90-120℃ and the reaction time is 6-20h.

[0055] Furthermore, in step 2), the reaction is carried out in a solvent, which is one of DMSO, DMF, DMAC, DMC, sulfolane, acetonitrile, and tetrahydrofuran. More preferably, DMSO is used as the solvent to obtain better experimental results.

[0056] In some specific embodiments, the length of the glass tube can be 15cm, 16cm, 17cm, 18cm, 19cm, 20cm, 21cm, 22cm, 23cm, 24cm, or 25cm. The radius can be 5cm, 6cm, 7cm, 8cm, 9cm, or 10cm. Generally, when the length of the glass tube is 15cm, 20cm, or 25cm, and the radius is 5cm, 7cm, or 10cm, better experimental results can be obtained.

[0057] In some specific embodiments, the ratio of CTF-3-2F to pyridine monomer can be 100 mg:100 μL, 110 mg:100 μL, 120 mg:100 μL, 130 mg:100 μL, 140 mg:100 μL, 150 mg:100 μL, 160 mg:100 μL, 170 mg:100 μL, 180 mg:100 μL, 190 mg:100 μL, 200 mg:100 μL, 210 mg:100 μL, 220 mg:100 μL, 230 mg:100 μL, etc. mg:100μL, 240mg:100μL, 250mg:100μL, 260mg:100μL, 270mg:100μL, 280mg:100μL, 290mg:100μL, 300mg:100μL, 10 0mg:200μL, 110mg:200μL, 120mg:200μL, 130mg:200μL, 140mg:200μL, 150mg:200μL, 160mg:200μL, 170mg:200μL, 18 0mg:200μL, 190mg:200μL, 200mg:200μL, 210mg:200μL, 230mg:200μL, 240mg:200μL, 250mg:200μL, 260mg:200μL, 2 70mg:200μL, 280mg:200μL, 290mg:200μL, 300mg:200μL, 100mg:300μL, 110mg:300μL, 120mg:300μL, 130mg:300μL, 1 40mg:300μL, 150mg:300μL, 160mg:300μL, 170mg:300μL, 180mg:300μL, 190mg:300μL, 200mg:300μL, 210mg:300μL, 220mg:300μL, 230mg:300μL, 240mg:300μL, 250mg:300μL, 260mg:300μL, 270mg:300μL, 280mg:300μL, 290mg:300μL.

[0058] In some specific embodiments, in step 2), the reaction temperature can be 90℃, 95℃, 100℃, 105℃, 110℃, 115℃, or 120℃, and the reaction time can be 6h, 7h, 8h, 9h, 10h, 11h, 12h, 13h, 14h, 15h, 16h, 17h, 18h, 19h, or 20h. Generally, in step 2), a reaction temperature of 90℃, 100℃, or 120℃, and a reaction time of 6h, 14h, or 20h can achieve better experimental results.

[0059] Example 1

[0060] The method for preparing the covalent triazine framework derivative in this embodiment includes the following steps:

[0061] 1) A covalent triazine framework was prepared using the classic tube-sealing method: (0.4 mmol) of a fluorinated monomer (2',5'-difluoro-[1,1':4',1-terphenyl]-4,4-dionitrile) and (0.3 mmol) of a Lewis acid catalyst (trifluoroacetic acid) were mixed and added to a quartz glass tube 15 cm long and 5 mm in radius. The glass tube was then melt-sealed at high temperature. The sealed glass tube was then placed in a muffle furnace at 200 °C for 10 h. After the reaction, the quartz glass tube was cooled to room temperature and opened. The granular product was pulverized and soaked overnight in hydrochloric acid solution, then washed sequentially with deionized water, ethanol, DMF, and THF. After filtration, it was vacuum-dried at 100 °C for 12 h to obtain CTF-3-2F.

[0062] 2) Place 100 mg of CTF-3-2F obtained in step 1) into a round-bottom flask, add 30 mL of DMSO solution, sonicate for 30 min, then add 200 mg of potassium tert-butoxide and (100 μL) of pyridine monomer (2-aminopyridine). Reflux at 90 °C for 6 h. Wash successively with deionized water and ethanol. After filtration, vacuum dry at 100 °C for 12 h to obtain CTF-3-Apy (a covalent triazine framework derivative).

[0063] Example 2

[0064] The method for preparing the covalent triazine framework derivative in this embodiment includes the following steps:

[0065] 1) A covalent triazine framework was prepared using the classic tube-sealing method: (0.7 mmol) of a fluorinated monomer (2',3',5',6'-tetrafluoro-[1,1':4',1-terphenyl]-4,4-dionitrile) and (0.5 mmol) of a Lewis acid catalyst (trifluoromethanesulfonic acid) were mixed and added to a quartz glass tube 20 cm long and 7 mm in radius. The glass tube was then melt-sealed at high temperature. The sealed glass tube was then placed in a muffle furnace at 300 °C for 15 h. After the reaction, the quartz glass tube was cooled to room temperature and opened. The granular product was pulverized and soaked overnight in hydrochloric acid solution, then washed sequentially with deionized water, ethanol, DMF, and THF. After filtration, it was vacuum-dried at 100 °C for 12 h to obtain CTF-3-2F.

[0066] 2) Place 200 mg of CTF-3-2F obtained in step 1) into a round-bottom flask, add 500 mL of DMSO solution, sonicate for 50 min, then add 200 mg of potassium tert-butoxide and (200 μL) of pyridine monomer (3-aminopyridine). Reflux at 100 °C for 14 h. Wash successively with deionized water and ethanol. After filtration, vacuum dry at 100 °C for 12 h to obtain CTF-3-Apy (a covalent triazine framework derivative).

[0067] Example 3

[0068] The method for preparing the covalent triazine framework derivative in this embodiment includes the following steps:

[0069] 1) A covalent triazine framework was prepared using the classic tube-sealing method: 1 mmol of a fluorinated monomer (2',5'-difluoro-[1,1':4',1-terphenyl]-4,4-dionitrile) and 0.7 mmol of a Lewis acid catalyst (trifluoromethanesulfonic acid) were mixed and added to a quartz glass tube 25 cm long and 10 mm in radius. The glass tube was then melt-sealed at high temperature. The sealed glass tube was then placed in a muffle furnace at 400 °C for 20 h. After the reaction, the quartz glass tube was cooled to room temperature and opened. The granular product was pulverized and soaked overnight in hydrochloric acid solution, then washed sequentially with deionized water, ethanol, DMF, and THF. After filtration, it was vacuum-dried at 100 °C for 12 h to obtain CTF-3-2F.

[0070] 2) Place 300 mg of CTF-3-2F obtained in step 1) into a round-bottom flask, add 60 mL of DMSO solution, sonicate for 60 min, then add 200 mg of potassium tert-butoxide and (300 μL) of pyridine monomer (4-aminopyridine). Reflux at 120 °C for 20 h. Wash successively with deionized water and ethanol. After filtration, vacuum dry at 100 °C for 12 h to obtain CTF-3-Apy (a covalent triazine framework derivative).

[0071] Performance testing

[0072] 1. Take the CTF-3-2F (chemical structure as shown in Example 3) obtained in Example 3. Figure 1 As shown on the left), XRD and scanning electron microscopy tests were performed, and the test results are as follows. Figure 2 and Figure 3 As shown.

[0073] 2. Take the CTF-3-Apy (chemical structure as shown in Example 3) prepared in Example 3. Figure 1 As shown on the right), infrared spectroscopy was performed, and the test results are as follows. Figure 4 As shown.

[0074] 3. Take 5 mg of CTF-3-Apy catalyst and 5 mg of conductive carbon black prepared in Example 3 and add them to a mixed solvent (DMF:Nafion=490μL:10μL). Sonicate for 30 min. Take 10 μL and drop it onto the surface of a rotating ring electrode. After drying, perform electrocatalytic performance testing.

[0075] Test results are as follows Figure 5 and Figure 6 As shown, Figure 5 and Figure 6 These are schematic diagrams of electrocatalytic oxygen reduction LSV and selectivity, and analysis is performed. Figure 5 and Figure 6 It can be seen that the covalent triazine framework derivatives prepared in this application have good catalytic performance.

[0076] Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this invention.

Claims

1. A method for preparing a covalent triazine framework derivative, characterized in that: Includes the following steps: 1) A fluorinated monomer is polymerized under the action of a catalyst to obtain CTF-3-2F; the fluorinated monomer is 2',5'-difluoro-[1,1':4',1-terphenyl]-4,4-dionitrile or 2',3',5',6'-tetrafluoro-[1,1':4',1-terphenyl]-4,4-dionitrile; 2) Take the CTF-3-2F obtained in step 1) and react it with the pyridine monomer to obtain CTF-3-Apy; the pyridine monomer is one of 2-aminopyridine, 3-aminopyridine, and 4-aminopyridine.

2. The method for preparing the covalent triazine framework derivative according to claim 1, characterized in that: In step 1), the catalyst is a Lewis acid catalyst; And / or, in step 1), the molar ratio of the fluorinated monomer to the catalyst is (0.2-1):(0.2-0.7).

3. The method for preparing the covalent triazine framework derivative according to claim 2, characterized in that: The Lewis acid catalyst is one of trifluoromethanesulfonic acid, trifluoroacetic acid, hydrochloric acid, sulfuric acid, and acetic acid.

4. The method for preparing the covalent triazine framework derivative according to claim 1, characterized in that: The polymerization reaction is carried out under sealed conditions with a temperature of 200-400℃ and a holding time of 10-20h.

5. The method for preparing the covalent triazine framework derivative according to claim 4, characterized in that: The heat preservation reaction under sealed conditions involves placing the fluorine-containing monomer and catalyst inside a glass tube, melting and sealing the glass tube, and then carrying out the heat preservation reaction.

6. The method for preparing the covalent triazine framework derivative according to claim 5, characterized in that: The glass tube is 15-25cm long and has a radius of 5-10mm.

7. The method for preparing the covalent triazine framework derivative according to claim 1, characterized in that: In step 2), the ratio of CTF-3-2F to pyridine monomer is (100-300) mg:(100-300) μL; And / or, in step 2), the reaction temperature is 90-120℃ and the reaction time is 6-20h.

8. The method for preparing the covalent triazine framework derivative according to claim 7, characterized in that: In step 2), the reaction is carried out in a solvent, which is one of DMSO, DMF, DMAC, DMC, sulfolane, acetonitrile, and tetrahydrofuran.

9. A covalent triazine framework derivative, characterized in that: It is prepared by any one of the preparation methods described in claims 1-8.

10. The application of a covalent triazine framework derivative in electrocatalytic oxygen reduction, characterized in that: The covalent triazine framework derivatives prepared by any of the preparation methods described in claims 1-8 or the covalent triazine framework derivatives described in claim 9 are used for electrocatalytic degradation of organic pollutants, metal-air batteries, electrocatalytic water splitting, and carbon dioxide reduction.

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