Crystalline CTF material and gas-solid phase interface catalytic preparation method

Abstract

The invention belongs to the field of CTF materials, and particularly relates to a crystalline CTF material and a gas-solid phase interface catalytic preparation method. The preparation method comprises the following steps: 1) reacting a cyano monomer with gas-phase organic superacid to obtain a protonated CTF material; and 2) reacting the protonated CTF material obtained in the step 2) with alkali for deprotonation to obtain the CTF material. The invention provides a method for preparing a high-crystallinity CTFs framework material through organic superacid gas-solid phase interface catalysis. According to the present invention, the cyano monomer and the organic superacid are subjected to gas-solid phase contact, such that the gaseous organic superacid is adopted as the catalyst to catalyze the cyano monomer polymerization so as to obtain the crystalline product at the low temperature within the short time, and the 20 g-grade high crystallinity sample can be rapidly prepared by using the method, the composite material is applied to the field of hydrogen and oxygen production through photocatalytic complete water splitting, and shows excellent performance.

Description

Technical Field

[0001] The present invention belongs to the field of CTF materials, and particularly relates to a crystalline CTF material and a gas-solid phase interface catalysis preparation method. Background Art

[0002] Covalent Triazine Frameworks (CTFs) materials are a new type of framework materials developed from traditional covalent organic framework materials and constructed by connecting triazine rings. Covalent triazine framework materials have a stable structure and are relatively easy to control the macroscopic morphology, making them have broad application prospects in the fields of gas storage and separation, catalysis, etc.

[0003] At the present stage, highly crystalline covalent triazine framework materials are often prepared by the trimerization reaction of nitrile monomers catalyzed by strong Lewis acids. For example, under 600 °C and zinc chloride catalysis, terephthalonitrile can undergo a trimerization reaction to construct a covalent triazine framework CTF. However, such methods require relatively high temperatures (above 550 °C) and the participation of strong Lewis acids (zinc chloride or phosphorus pentoxide), the reaction conditions are harsh, the CTF framework prepared has poor crystallinity, small specific surface area, and it is difficult to remove the catalyst from the framework, with large residues, and it is difficult to prepare on a large scale.

[0004] Subsequently, a series of mild methods for preparing CTFs have been developed. For example, using terephthalaldehyde or terephthalylbenzyl alcohol and terephthalimidamidine hydrochloride to dehydrate and condense, and oxidize and cyclize under mild alkaline conditions (below 120 °C, cesium carbonate), a highly crystalline CTF framework material can be prepared. However, the price costs of terephthalimidamidine hydrochloride (~28kUSD / kg) and cesium carbonate (~0.15kUSD / kg) are relatively high, and the solvent (DMSO) used is toxic and easily causes environmental pollution.

[0005] Recently, a method for synthesizing CTF by liquid-phase catalysis with trifluoromethanesulfonic acid has been developed. Under the condition of 250 °C, trifluoromethanesulfonic acid catalyzes the trimerization reaction of molten terephthalonitrile to construct a highly crystalline triazine framework CTF. However, this method also has the problems that it is difficult to remove the catalyst from the framework and the residues are large. Secondly, due to the electrostatic interaction of the triazine groups protonated by trifluoromethanesulfonic acid between the CTF layers, the stacking mode of the prepared CTF material is AB stacking, and the adsorption performance and light absorption performance are poor. Therefore, high-temperature treatment at 350 °C is required to volatilize trifluoromethanesulfonic acid before the stacking mode of the CTF material can be changed to AA stacking, and large-scale preparation is limited. At the same time, because the liquid-phase catalysis method of trifluoromethanesulfonic acid requires heating the monomer to the molten state, it cannot prepare functionalized CTF materials with monomers being high melting point compounds. Summary of the Invention

[0006] The object of the present invention is to overcome the disadvantages in the prior art and provide a crystalline CTF material and a gas-solid interface catalytic preparation method.

[0007] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0008] A method for gas-solid interface catalytic preparation of a crystalline CTF material, comprising the following steps: 1) reacting a cyano monomer with a gaseous organic superacid to obtain a protonated CTF material; 2) reacting the protonated CTF material obtained in step 2) with a base to deprotonate and obtain a CTF material.

[0009] The cyano monomer is one or a mixture of terephthalonitrile, benzene-1,3,5-tricarbonitrile, biphenyl-4,4'-dicarbonitrile, 1,2,4,5-benzenetetracarbonitrile, 1,3,5-tris(4'-cyanophenyl)benzene, 5,15-bis(4'-cyanophenyl)porphyrin, 5,10,15,20-tetrakis(4'-cyanophenyl)porphyrin, tetrakis(4'-cyanophenyl)methane, 1,3,5,7-tetrakis(4'-cyanophenyl)adamantane, 5,15-bis(4'-cyanophenyl)-10-pentafluorophenyl-corrole, 5,15-bis(4'-cyanophenyl)-10-phenyl-corrole, 5,15-bis(4'-cyanophenyl)-10-trifluoromethyl-corrole, 5,15-bis(4'-cyanophenyl)-10-pentafluorophenyl-boron difluoride pyrromethene.

[0010] The organic superacid in step 1) is one or a mixture of trifluoromethanesulfonic acid, methylsulfonic acid, trifluoroacetic acid, p-toluenesulfonic acid, bis(trifluoromethanesulfonyl)imide, fluorosulfonic acid, fluoroantimonic acid.

[0011] The base in step 2) is an aqueous solution of a volatile base; the aqueous solution of the volatile base is one or a mixture of 24% ammonia water, 80% hydrazine hydrate, 40% aqueous methylamine solution.

[0012] For the method for gas-solid interface catalytic preparation of a crystalline CTF material, the reaction is carried out using a preparation device, and the preparation device includes an external reaction container with good airtightness for placing a cyano monomer and an inner tube arranged in the external reaction container; the inner tube is provided with an opening; the inner reaction tube is used to place an organic superacid or a base.

[0013] The specific steps of step 1) are: adding the cyano monomer to the bottom of the external reaction container, then adding the organic superacid into the inner tube, repeatedly displacing with an inert gas, and then placing the device in an environment above the boiling point of the organic superacid for reaction; after waiting for the reaction device to return to room temperature, taking out the reaction inner tube, and the solid at the bottom of the bottle is the protonated CTF material.

[0014] The specific steps of step 2) are as follows: Take a new inner tube, add alkali into it, place it in the external reaction vessel in step 1), displace it with an inert gas, then place the device in the volatilization temperature of the alkali for reaction. After completion, take out the solid in the external reaction vessel, wash and dry it to obtain the deprotonated crystalline CTF material.

[0015] The addition amount of the organic superacid is 0.1 - 0.5 equivalents of the cyano monomer.

[0016] The addition amount of the alkali is 5 - 10 equivalents of the cyano monomer.

[0017] The present invention also includes a crystalline CTF material obtained by the method described above. The crystalline CTF material is a polymer of a crown compound.

[0018] Preferably, the crown compound is formed by connecting multiple triazine units. Each triazine unit includes 1,3,5 - s - triazine and a benzene ring or a benzene derivative.

[0019] Preferably, the total number of 1,3,5 - s - triazine or benzene rings forming the crown ring in the crown compound is n, where 6 < n < 18.

[0020] Preferably, the crown compound is one of CTF materials 1, 2, and 4.

[0021]

[0022] The present invention also includes a crystalline CTF material obtained by the method described above, which is applied to photocatalytic overall water splitting for producing hydrogen and oxygen.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] The present application provides a method for preparing a highly crystalline CTFs framework material by gas - solid phase interface catalysis with an organic superacid. The cyano monomer and the organic superacid are in gas - solid phase contact, and the gaseous organic superacid is used as a catalyst to catalyze the polymerization of the cyano monomer. Crystalline products can be obtained at a relatively low temperature and in a relatively short time. At the same time, this method can quickly prepare a twenty - gram - level highly crystalline sample, which is applied to the field of photocatalytic overall water splitting for producing hydrogen and oxygen and shows excellent performance. This method (1) is efficient and green; (2) has strong monomer scalability; (3) can be prepared in large batches; (4) the prepared CTFs framework material has good photocatalytic hydrogen - producing and oxygen - producing properties. Description of the Drawings

[0025] Figure 1 It is the structural formula of the CTFs material prepared in the embodiment of the present invention.

[0026] Figure 2Structural formula of the monomer used for preparing CTF materials in the embodiments of the present invention;

[0027] Figure 3 X-ray diffraction patterns and molecular structures of CTF materials 1, 2, 3, 4, 5, and 7 prepared in the embodiments of the present invention;

[0028] Figure 4 Scanning electron microscope images of CTF materials 1, 2, 3, 4, 5, and 7 prepared in the embodiments of the present invention;

[0029] Figure 5 X-ray diffraction pattern of CTF material 1 prepared in the enlarged experiment of the embodiments of the present invention;

[0030] Figure 6 Photocatalytic performance of CTF materials 1, 2, 3, 4, 5, and 7 prepared in the embodiments of the present invention;

[0031] Figure 7 Preparation device for preparing crystalline CTF materials by gas-solid phase interface catalysis as described above. Detailed implementation manners

[0032] In order to enable those skilled in the art of the present technology to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and the best embodiments.

[0033] Figure 7 A preparation device for preparing crystalline CTF materials by gas-solid phase interface catalysis as described above is shown. The preparation device includes an external reaction container with good airtightness for placing cyano monomers and an inner tube disposed in the external reaction container; the inner tube is provided with an opening; and an organic superacid or base is placed in the inner reaction tube.

[0034] When using this device to prepare CTF of triazine framework materials, it should be noted that the implementation scheme of the present invention is not limited to this device, and any device capable of performing gas-solid reactions can be used.

[0035] A method for preparing crystalline CTF materials by gas-solid phase interface catalysis of the present invention includes the following steps: 1) Reacting a cyano monomer with a gaseous organic superacid to obtain a protonated CTF material; 2) Reacting the protonated CTF material obtained in step 2) with a base to deprotonate and obtain a CTF material.

[0036] The cyanide monomers described above may specifically be one or a mixture of terephthalonitrile, benzene-1,3,5-tricarbonitrile, biphenyl-4,4'-dicarbonitrile, 1,2,4,5-benzenetetracarbonitrile, 1,3,5-tris(4'-cyanophenyl)benzene, 5,15-bis(4'-cyanophenyl)porphyrin, 5,10,15,20-tetrakis(4'-cyanophenyl)porphyrin, tetrakis(4'-cyanophenyl)methane, 1,3,5,7-tetrakis(4'-cyanophenyl)adamantane, 5,15-bis(4'-cyanophenyl)-10-pentafluorophenyl-corrole, 5,15-bis(4'-cyanophenyl)-10-phenyl-corrole, 5,15-bis(4'-cyanophenyl)-10-trifluoromethyl-corrole, 5,15-bis(4'-cyanophenyl)-10-pentafluorophenyl-borondipyrromethene.

[0037] Specific cyanide monomers such as Figure 2 shown, using such cyanide monomers for polymerization can obtain various CTF materials, and the typical CTF material structure is as Figure 1 shown.

[0038] The following preferred embodiments will be described.

[0039] Example 1

[0040] Synthesis of triazine framework material CTF material 1 ( Figure 1 the 1 in it, the same below):

[0041] 1) At room temperature, add 600 mg of monomer 11 ( Figure 2 the 11 in it, the same below) terephthalonitrile to the bottom of the external reaction vessel, then add 250 μL of trifluoromethanesulfonic acid (0.25e) to the inner tube, displace it with nitrogen three times repeatedly, and then place the device in an oven at 180 °C for 12 h. After waiting for the reaction device to return to room temperature, take out the reaction inner tube, and the orange solid obtained at the bottom of the bottle is the protonated CTF material.

[0042] 2) Take a new reaction inner tube, add 5 mL of 24% ammonia water solution (5e) to it, place it in the above reaction device, displace it with nitrogen three times repeatedly, and then place the device in an oven at 50 °C for 36 h. Take out the solid at the bottom of the bottle, and wash the solid with deionized water, ethanol, and dichloromethane to obtain 584 mg of crystalline CTF material 1, with a yield of 97.3%.

[0043] It can be known from X-ray diffraction analysis ( Figure 3 ), the X-ray diffraction pattern of CTF material 1 prepared by the above method has 4 relatively strong diffraction peaks, at 7.5°, 12.5°, 14.8°, and 25.2° respectively. Among them, the diffraction peak intensity of the (100) crystal plane corresponding to 7.5° is relatively strong, proving that the obtained CTF material 1 has good crystallinity. Figure 4Show its corresponding scanning electron microscope atlas.

[0044] Example 2

[0045] Synthesis of triazine framework material CTF material 2:

[0046] 1) At room temperature, add 600 mg of monomer 12, biphenyldicarbonitrile, to the bottom of the external reaction vessel, and then add 250 μL of trifluoromethanesulfonic acid (0.25 e) to the inner tube. Replace with argon three times repeatedly, and then place the device in an oven at 180 °C for 12 h. After waiting for the reaction device to return to room temperature, take out the reaction inner tube, and a red solid is obtained at the bottom of the bottle.

[0047] 2) Take a new reaction inner tube, add 5 mL of 24% aqueous ammonia solution (5 e) to it, place it in the above reaction device, replace with argon three times repeatedly, and then place the device in an oven at 50 °C for 24 h. Take out the solid at the bottom of the bottle, and wash the solid with deionized water, ethanol, and dichloromethane to obtain 579 mg of crystalline CTF material 2, with a yield of 96.5%.

[0048] It can be known from X-ray diffraction analysis ( Figure 3 ) that the X-ray diffraction pattern of CTF material 2 prepared by the above method has 4 strong diffraction peaks, at 4.8°, 8.5°, 12.8°, and 25.4° respectively. Among them, the diffraction peak intensity of the (100) crystal plane corresponding to 4.8° is stronger, proving that the obtained CTF material 2 has good crystallinity. Figure 4 Show its corresponding scanning electron microscope atlas.

[0049] Example 3

[0050] Synthesis of triazine framework material CTF material 3:

[0051] 1) At room temperature, add 600 mg of monomer 13, benzene-1,3,5-tricarbonitrile, to the bottom of the external reaction vessel, and then add 200 μL of trifluoromethanesulfonic acid (0.2 e) to the inner tube. Replace with nitrogen three times repeatedly, and then place the device in an oven at 180 °C for 12 h. After waiting for the reaction device to return to room temperature, take out the reaction inner tube, and a green solid is obtained at the bottom of the bottle.

[0052] 2) Take a new reaction inner tube, add 5 mL of 80% hydrazine hydrate aqueous solution (10 e) to it, place it in the above reaction device, replace with nitrogen three times repeatedly, and then place the device in an oven at 50 °C for 24 h. Take out the solid at the bottom of the bottle, and wash the solid with deionized water, ethanol, and dichloromethane to obtain 593 mg of crystalline CTF material 5, with a yield of 98.3%.

[0053] It can be known from X-ray diffraction analysis ( Figure 3) The X-ray diffraction pattern of the CTF material 5 prepared by the above method has multiple strong diffraction peaks at 3.5°, 7.2°, 11.8°, and 22.3°, respectively. Among them, the diffraction peak intensity corresponding to the (100) crystal plane at 3.5° is relatively strong, indicating that the obtained CTF material 5 has good crystallinity. Figure 4 Show its corresponding scanning electron microscope image.

[0054] Example 4

[0055] Synthesis of the triazine framework material CTF material 4:

[0056] 1) At room temperature, add 600 mg of monomer 14, 1,3,5-tris(4'-cyanophenyl)benzene to the bottom of the external reaction vessel, and then add 250 μL of trifluoromethanesulfonic acid (0.25 e) into the inner tube. Replace with argon three times repeatedly, and then place the device in an oven at 180 °C for 12 h. After waiting for the reaction device to return to room temperature, take out the inner reaction tube, and a purple-black solid is obtained at the bottom of the bottle.

[0057] 2) Take a new inner reaction tube, add 5 mL of 80% hydrazine hydrate aqueous solution (10 e) into it, place it in the above reaction device, replace with argon three times repeatedly, and then place the device in an oven at 50 °C for 24 h. Take out the solid at the bottom of the bottle, and wash the solid with deionized water, ethanol, and dichloromethane to obtain 583 mg of crystalline CTF material 6, with a yield of 97.2%.

[0058] It can be known through X-ray diffraction analysis ( Figure 3 ) that the X-ray diffraction pattern of the CTF material 6 prepared by the above method has multiple strong diffraction peaks at 5.3°, 7.5°, 9.3°, and 25.7°, respectively. Among them, the diffraction peak intensity corresponding to the (100) crystal plane at 5.3° is relatively strong, indicating that the obtained CTF material 6 has good crystallinity. Figure 4 Show its corresponding scanning electron microscope image.

[0059] Example 5

[0060] Synthesis of the triazine framework material CTF material 5:

[0061] 1) At room temperature, add 600 mg of monomer 15, 5,15-bis(4'-cyanophenyl)porphyrin to the bottom of the external reaction vessel, and then add 500 μL of trifluoromethanesulfonic acid (0.5 e) into the inner tube. Replace with argon three times repeatedly, and then place the device in an oven at 180 °C for 12 h. After waiting for the reaction device to return to room temperature, take out the inner reaction tube, and a purple solid is obtained at the bottom of the bottle.

[0062] 2) Take a new reaction inner tube, add 5 mL of 80% hydrazine hydrate aqueous solution (10e) into it, place it in the above reaction device, displace it with argon three times repeatedly, then place the device in an oven at 50 °C for 24 h. Take out the solid at the bottom of the bottle, wash the solid with deionized water, ethanol, and dichloromethane to obtain 562 mg of crystalline CTF material 7, with a yield of 94.1%.

[0063] It can be known from X-ray diffraction analysis that ( Figure 3 ), the X-ray diffraction pattern of the CTF material 7 prepared by the above method has multiple strong diffraction peaks, at 8.1°, 13.4°, and 22.5° respectively, proving that the obtained CTF material 7 has good crystallinity. Figure 4 Show its corresponding scanning electron microscope image.

[0064] Example 6

[0065] Synthesis of triazine framework material CTF material 7:

[0066] 1) At room temperature, add 600 mg of monomer 17, tetrakis(4'-cyanophenyl)methane to the bottom of the external reaction vessel, then add 100 μL of trifluoromethanesulfonic acid (0.1e) into the inner tube, displace it with argon three times repeatedly, and then place the device in an oven at 180 °C for 24 h. After waiting for the reaction device to return to room temperature, take out the reaction inner tube, and a black solid is obtained at the bottom of the bottle.

[0067] 2) Take a new reaction inner tube, add 5 mL of 23% ammonia aqueous solution (5e) into it, place it in the above reaction device, displace it with argon three times repeatedly, then place the device in an oven at 80 °C for 24 h. Take out the solid at the bottom of the bottle, wash the solid with deionized water, ethanol, and dichloromethane to obtain 591 mg of crystalline CTF material 9, with a yield of 97.8%.

[0068] It can be known from X-ray diffraction analysis that the X-ray diffraction pattern of the CTF material 9 prepared by the above method has strong diffraction peaks, proving that the obtained CTF material 9 has good crystallinity.

[0069] Example 8

[0070] Scale-up synthesis of triazine framework material CTF material 1:

[0071] 1) At room temperature, add 12 g of terephthalonitrile to the bottom of a 200 mL Pyrex tube, then add 2 mL of trifluoromethanesulfonic acid (0.25e) into the inner tube, displace it with argon three times repeatedly, and then place the device in an oven at 180 °C for 12 h. After waiting for the reaction device to return to room temperature, take out the reaction inner tube, and an orange solid is obtained at the bottom of the bottle.

[0072] 2) Take a new reaction inner tube, add 50 mL of 24% aqueous ammonia solution (5e) into it, place it in the above-mentioned 200 mL Pyrex tube, displace it three times repeatedly with argon, then place the device in an oven at 80 °C and keep it for 24 h. Take out the solid at the bottom of the bottle, wash the solid with deionized water, ethanol, and dichloromethane to obtain 11.87 g of crystalline CTF material 1 with a yield of 98.9%. Figure 5 The X-ray diffraction pattern of CTF material 1 prepared by the scale-up experiment of this example is shown; it is proved that its crystallinity is good.

[0073] Example 9

[0074] Photocatalytic performance test:

[0075] 1) Photocatalytic hydrogen production test: Add 50 mg of CTF catalyst, 10 mL of triethanolamine, and 90 mL of deionized water into the reactor. After ultrasonic treatment for 30 min, add chloroplatinic acid solution so that the mass of platinum is about 3 wt% of the catalyst. Place the reactor under a xenon lamp equipped with a 420 nm cut-off filter for reaction, and analyze the generated gas by gas chromatography. The photocatalytic hydrogen production performances of CTF materials 1, 2, 3, 4, 5, and 7 are as Figure 6 shown in a. The photocatalytic hydrogen production performances of the CTF photocatalysts prepared in the examples are 184.1, 293.7, 1.08, 433.0, 2.16, and 0.512 μmol h -1 . The performance difference is presumably caused by the matching degree between the energy levels of the prepared photocatalyst and the photocatalytic hydrogen production energy level.

[0076] 2) Photocatalytic oxygen production test: Add 50 mg of CTF catalyst and 100 mL of 0.1 M silver nitrate solution into the reactor. After ultrasonic treatment for 30 min, add cobalt chloride so that the mass of cobalt is about 3 wt% of the catalyst. Place the reactor under a xenon lamp equipped with a 420 nm cut-off filter for reaction, and analyze the generated gas by gas chromatography. The photocatalytic oxygen production performances of CTF materials 1, 2, 3, 4, 5, and 7 are as Figure 6 shown in b. The photocatalytic hydrogen production performances of the CTF photocatalysts prepared in the examples are 2.86, 4.12, 0.098, 6.05, 0.19, and 0.073 μmol h -1 . The performance difference is presumably caused by the matching degree between the energy levels of the prepared photocatalyst and the photocatalytic oxygen production energy level.

[0077] Research shows that when the crystalline CTF material is a polymer of crown compounds, its photocatalytic performance is good. The crown compound is formed by connecting multiple triazine units; each triazine unit includes 1,3,5-s-triazine and a benzene ring or a benzene derivative;

[0078] Among them, the total number of 1,3,5-s-triazine or benzene rings forming the crown ring in the crown compound is n. When 6 < n < 18, good photocatalytic performance is shown. For example, the crown compound mentioned in the above embodiments is one of CTF materials 1, 2, and 4;

[0079]

[0080] In summary, the present application provides a method for preparing a highly crystalline CTFs framework material by gas-solid phase interface catalysis with an organic superacid. The cyanide monomer is brought into gas-solid contact with the organic superacid, and the gaseous organic superacid is used as a catalyst to catalyze the polymerization of the cyanide monomer, so that a crystalline product can be obtained at a relatively low temperature and in a relatively short time. At the same time, this method can be used to quickly prepare a twenty-gram-scale highly crystalline sample, which is applied to the field of photocatalytic overall water splitting to produce hydrogen and oxygen, showing excellent performance. This method (1) is efficient and green; (2) has strong monomer scalability; (3) can be prepared in large quantities; (4) the prepared CTFs framework material has good photocatalytic hydrogen production and oxygen production performance.

[0081] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A method for preparing crystalline CTF material by gas-solid interface catalysis, characterized in that: The method comprises the following steps: 1) reacting a cyano monomer with a gas phase organic superacid to obtain a protonated CTF material; and 2) reacting the protonated CTF material obtained in step 2) with a base to deprotonate the CTF material.

2. The method for preparing crystalline CTF material by gas-solid interface catalysis according to claim 1, characterized in that: The cyano monomer is one of terephthalonitrile, trimesonitrile, biphenyl dinitrile, 1,2,4,5-benzene tetranitrile, 1,3,5-tris(4'-cyanophenyl)benzene, 5,15-bis(4'-cyanophenyl)porphyrin, 5,10,15,20-tetra(4'-cyanophenyl)porphyrin, tetra(4'-cyanophenyl)methane, 1,3,5,7-tetra(4'-cyanophenyl)adamantane, 5,15-bis(4'-cyanophenyl)-10-pentafluorophenyl-corrole, 5,15-bis(4'-cyanophenyl)-10-phenyl-corrole, 5,15-bis(4'-cyanophenyl)-10-trifluoromethyl-corrole, 5,15-bis(4'-cyanophenyl)-10-pentafluorophenyl-fluoroboron dipyrrolmethane or a mixture thereof.

3. The method for preparing crystalline CTF material by gas-solid interface catalysis according to claim 1, characterized in that: The organic superacid described in step 1) is one of trifluoromethanesulfonic acid, trifluoromethanesulfonic acid, methanesulfonic acid, trifluoroacetic acid, p-toluenesulfonic acid, bis(trifluoromethanesulfonyl)imide, fluorosulfonic acid, and fluoroantimonic acid, or a mixture thereof.

4. The method for preparing crystalline CTF material by gas-solid interface catalysis according to claim 1, characterized in that: The base described in step 2) is an aqueous solution of a volatile base; the aqueous solution of a volatile base is one of 24% ammonia water, 80% hydrazine hydrate, and 40% methylamine aqueous solution, or a mixture thereof.

5. The method for preparing crystalline CTF material by gas-solid interface catalysis according to any one of claims 1 to 4, characterized in that: The reaction is carried out using a preparation device, which includes an external reaction container with good airtightness for placing a cyano monomer and an inner tube arranged in the external reaction container; the inner tube is provided with an opening; and the inner reaction tube is used to place an organic superacid or base.

6. The method for preparing crystalline CTF material by gas-solid interface catalysis according to claim 5, characterized in that: The specific steps of step 1) are: adding a cyano monomer to the bottom of an external reaction container, then adding an organic superacid to the inner tube, replacing it with an inert gas, and then placing the device in an environment higher than the boiling point of the organic superacid for reaction; after waiting for the reaction device to return to room temperature, taking out the inner reaction tube to obtain a solid protonated CTF material.

7. The method for preparing crystalline CTF material by gas-solid interface catalysis according to claim 6, characterized in that: The specific steps of step 2) are: take a new inner tube, add alkali into it, put it into the external reaction container in step 1), replace it with inert gas, and then place the device at the volatilization temperature of the alkali to react. After the reaction, take out the solid in the external reaction container, wash and dry it to obtain a deprotonated crystalline CTF material.

8. The method for preparing crystalline CTF material by gas-solid interface catalysis according to claim 6, characterized in that: The amount of the organic superacid added is 0.1-0.5 equivalents of the cyano monomer; and the amount of the base added is 5-10 equivalents of the cyano monomer.

9. A crystalline CTF material obtained by the method according to any one of claims 1 to 8, characterized in that: The crystalline CTF material is a polymer of crown compounds; Preferably, the crown compound is formed by connecting a plurality of triazine units; each of the triazine units comprises 1,3,5-s-triazine and a benzene ring or a benzene derivative; Preferably, the total number of 1,3,5-s-triazine or benzene rings forming the crown ring in the crown compound is n, 6<n<18; Preferably, the crown compound is one of CTF materials 1, 2, and 4; 10. A crystalline CTF material obtained by the method according to any one of claims 1 to 8, characterized in that: Applied to photocatalytic water splitting to produce hydrogen and oxygen.

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