Method for gamma irradiation enhanced hydrophilicity of covalent organic frameworks

Abstract

The present invention discloses a method for gamma irradiation enhanced hydrophilicity of covalent organic frameworks(COF). After the covalent organic framework is processed by gamma irradiation treatment, the hydrogen production rate increases significantly. Fourier transform infrared spectroscopy (FTIR) detected the hydroxyl groups in the covalent organic framework after gamma irradiation treatment and measured the contact angle. That is, gamma irradiation treatment improved the wettability of the COF, and XPS studies showed that chemical reaction changes occurred on the surface of the COF.

Description

Technical Field

[0001] This invention relates to a method for driving a covalent organic framework to be hydrophilic, particularly a method for enhancing the hydrophilicity of a covalent organic framework using gamma ray irradiation, with photocatalytic hydrogen production as the target application. Prior Technology

[0002] The development of modern energy technology aims to find new fuels that can replace fossil fuels and minimize the pollution of the Earth's reaction byproducts. Among these, the technology of using visible light to decompose water through photocatalysis to produce hydrogen offers possibilities for clean fuel development due to the non-toxic and stable nature of the fuel itself and the abundance of water resources on Earth. In the field of photocatalysis, a 2009 study discovered that metal-free organic polymeric graphitic carbonitrides (gC3N4) have the ability to decompose water under visible light irradiation, and further research revealed that other types of gC3N4 and their derivatives possess even higher stability and photocatalytic activity. Recently, the use of organic polymer catalysts as a photocatalytic platform has been developed, such as conjugated linear polymers, microporous polymers, and triazine frameworks. These organic polymers possess excellent properties in terms of cost-effectiveness, tunable structure, and photophysical characteristics, leading to breakthroughs in hydrogen production technology. The photocatalytic activity of such photocatalysts is influenced by various factors; for example, higher surface hydrophilicity of the photocatalyst facilitates its reaction with water, and easily accessible active sites can enhance its photocatalytic activity.

[0003] The design and application of the aforementioned polymers is a highly regarded field in modern materials science. The principle involves assembling and connecting different small structural units using various connection methods to form one-dimensional, two-dimensional, or three-dimensional structures. These connection methods include covalent bonding and π-π stacking arrangements. Common polymers, such as polyethylene, nylon, polyester compounds, or polyamine compounds formed by covalent polymerization of small structural units like olefins, amines, or organic acids, are widely used in modern daily life.

[0004] Among them, the covalent organic framework (COF) is a crystalline organic porous structure with a large surface area, an extended π-conjugated framework and a layered stacked structure. It has been shown to have high BET (Brunor-Emmett-Teller) specific surface area, low density, controllable pore size structure, easily adjustable properties, high material strength and chemical stability. It also has significant light collection potential and an adjustable band gap, and is therefore used as a photocatalyst material for generating hydrogen.

[0005] However, some challenges remain in the field of COF materials, such as low processability and difficulties in mass production. Because current COF materials are synthesized as insoluble, unprocessable powders with inherent cross-linking, they cannot be used in many applications. Furthermore, while two-dimensional (2D) COFs are well-suited for electronic devices, they cannot be successfully used for connecting electrodes or fabricating high-quality thin films, resulting in generally poor performance for COF-based optoelectronic devices.

[0006] Furthermore, COF photocatalysts have limited solubility in water, requiring the use of organic solvents for dissolution. This inevitably limits the interaction between the photocatalyst and water during the hydrogen evolution reaction (HER), thus reducing the effectiveness of these photocatalysts. To overcome this drawback, studies have proposed modifying the polymer backbone structure, such as hydrophilicity, to increase the dispersibility of organic photocatalysts in the reaction phase. According to Hu and colleagues, incorporating polar groups into hydrophobic conjugated structural units can increase wettability, thereby significantly improving photocatalytic activity. A common approach is to chemically introduce polar groups into hydrophobic COFs; however, chemical methods have many drawbacks, including the use of more chemicals, the generation of byproducts, and the inability to scale up production. The harsh solvothermal synthesis conditions can also negatively impact the crystallinity and surface area of ​​COFs. Therefore, finding a method to efficiently increase the hydrophilicity of COFs under general conditions is a current research goal in the industry. Summary of the Invention

[0007] The main objective of this invention is to provide a method for enhancing the hydrophilicity of a covalent organic framework by using gamma ray irradiation, which is used to generate the framework and improve its electrical properties.

[0008] To achieve the aforementioned main objective, this invention discloses a method for enhancing the hydrophilicity of a covalent organic framework using gamma irradiation. First, 4,4'-(benzo[c][1,2,5]thiadiazole-4,7-diyl)dibenzaldehyde and 4,4',4'',4'''-(pyrene-1,3,6,8-tetraphenyl)tetraphenylamine are passed through a catalyst and heated to generate a crystalline covalent organic framework compound. The dried crystalline covalent organic framework compound is then added to an organic solvent to form a first solution. Next, the first solution is irradiated with gamma rays to generate a hydrophilic crystalline covalent organic framework compound, Py-BT γ-COF, with the following structural formula: .

[0009] The present invention provides an embodiment in which the catalyst comprises acetic acid.

[0010] The present invention provides an embodiment in which the heating temperature is 100°C to 160°C in the step of adding a catalyst and heating to generate a crystalline covalent organic framework compound.

[0011] The present invention provides an embodiment in which the organic solvent comprises o-chlorobenzene and n-butanol.

[0012] The present invention provides an embodiment in which the gamma ray irradiation intensity is 0.809 k Gy / h and the gamma ray irradiation time is 2 hours.

[0013] This invention also discloses a method for enhancing the hydrophilicity of covalent organic frameworks using gamma ray irradiation. First, 4,4'-(benzo[c][1,2,5]thiadiazole-4,7-diyl)dibenzaldehyde and 4,4',4'',4'''-(pyrene-1,3,6,8-tetraphenyl)tetraphenylamine are added to an organic solvent to form a second solution. Then, this second solution is irradiated with gamma rays to generate an amorphous covalent organic framework compound. Finally, the amorphous covalent organic framework compound is heated to generate a crystalline covalent organic framework compound, wherein the crystalline covalent organic framework compound is Py-BT γ-COF, and its structural formula is [insert structural formula here]. .

[0014] The present invention provides another embodiment in which the heating temperature in the step of heating the amorphous covalent organic framework compound is 100°C to 160°C.

[0015] The present invention provides another embodiment in which the organic solvent comprises o-chlorobenzene and n-butanol.

[0016] The present invention provides another embodiment in which the gamma ray irradiation intensity is 0.809 k Gy / h and the gamma ray irradiation time is 2 hours. Simple Explanation of the Diagram

[0017] Figure 1 is a flowchart of the first embodiment of the present invention; Figure 2 is a flowchart of the second embodiment of the present invention; Figure 3 is a schematic diagram of the structure of the hydrophilic crystalline covalent organic framework compound of the present invention; Figure 4 is a schematic diagram of the first stacking configuration of the hydrophilic crystalline covalent organic framework compound of the present invention; Figure 5 is a schematic diagram of the second stacking configuration of the hydrophilic crystalline covalent organic framework compound of the present invention; Figure 6 is a comparison diagram of the crystallinity of the crystalline phase covalent organic framework compounds of the present invention; Figures 7A and 7B show the crystallization state of the non-hydrophilic crystalline covalent organic framework compound of this invention at different magnifications in SEM images; Figures 8A and 8B show the crystallization state of the hydrophilic crystalline covalent organic framework compound of the present invention at different magnifications in SEM images; Figures 9A and 9B show the crystallization state of the non-hydrophilic crystalline covalent organic framework compound of this invention under different magnifications in TEM images. Figures 10A and 10B show the crystallization state of the hydrophilic crystalline covalent organic framework compound of the present invention at different magnifications in TEM images; Figure 11A shows the hydrophilicity results of the non-hydrophilic crystalline phase covalent organic framework compound of the present invention; Figure 11B shows the hydrophilicity results of the hydrophilic crystalline covalent organic framework compound of the present invention; Figure 12A shows the ultraviolet-visible spectrum of the crystalline covalent organic framework compound of this invention; Figure 12B shows the optical bandgap difference of the crystalline covalent organic framework compound of the present invention; Figure 12C is a schematic diagram of the LUMO energy levels of the crystalline covalent organic framework compound of this invention; Figure 13A shows the hydrogen production results of the crystalline covalent organic framework compound of this invention; Figure 13B shows the apparent quantum yield of hydrogen release from the crystalline covalent organic framework compound of the present invention at different wavelengths; and Figure 13C shows the results of long-term hydrogen production performance of the hydrophilic crystalline covalent organic framework compound of the present invention combined with a photocatalyst under visible light catalysis. Implementation

[0018] To enable your review committee to gain a better understanding of the features and effects of this invention, the invention will be described in detail below with reference to the accompanying drawings, illustrating various embodiments. However, the concept of this invention may be embodied in many different forms and should not be construed as limited to the exemplary embodiments set forth herein.

[0019] The covalent organic framework (COF) provided by this invention is a novel class of crystalline porous polymers that has attracted widespread attention due to its pre-designed structure and customized functions, and is considered a new platform for the efficient conversion of solar energy into hydrogen. The COF provided by this invention, after gamma ray irradiation, exhibits increased hydrophilicity, thereby enhancing its photocatalytic performance. After gamma ray irradiation, the hydrogen yields of Py-BTγ-COF(A) and Py-BTγ-COF(B) increased by 11.8 times and 18.0 times, respectively. Fourier transform infrared spectroscopy (FTIR) detection of the hydroxyl groups after gamma ray treatment, along with contact angle measurements, showed that gamma ray treatment significantly improved the hydrophilicity of the COF. Further X-ray photoelectron spectroscopy (XPS) studies indicated that chemical changes occurred on the surface of the treated COF.

[0020] First, please refer to Figure 1, which is a flowchart of the first embodiment of the present invention.

[0021] As shown in Figure 1, the method of the present invention for enhancing the hydrophilicity of a covalent organic framework by gamma ray irradiation includes:

[0022] Step S11: Add 4,4'-(benzo[c][1,2,5]thiadiazole-4,7-diyl)dibenzaldehyde and 4,4',4'',4'''-(pyrene-1,3,6,8-tetrayl)tetraphenylamine, and add a catalyst and heat to generate a crystalline covalent organic framework compound;

[0023] Step S13: Add the dried crystalline covalent organic framework compound to an organic solvent to form a first solution; and

[0024] Step S15: Irradiate the first solution with gamma rays to generate a hydrophilic covalent organic framework compound of the crystal phase.

[0025] In step S11, a solvothermal synthesis method is used. 4,4'-(benzo[c][1,2,5]thiadiazole-4,7-diyl)dibenzaldehyde and 4,4',4'',4'''-(pyrene-1,3,6,8-tetrayl)tetraphenylamine are dissolved in an organic solvent in a 25 mL Schlenk tube. In this example, the organic solvent is a mixture of o-chlorobenzene and n-butanol (1:1, v / v). After dissolution, acetic acid (6M) is added as a catalyst, and the mixture is heated to a specific temperature to generate a solid crystalline covalent organic framework compound. This heating temperature can be between 100°C and 160°C.

[0026] Following step S13, the generated Py-BT COF solid is washed with an organic solvent and vacuum dried. The Py-BT COF solid is then transferred to a 20 mL glass bottle and mixed with an organic solvent (in this example, a mixture of o-chlorobenzene and n-butanol (1:1, v / v) is used as an example) to form a first solution containing Py-BT COF. Then, in step S15, the first solution containing Py-BT COF is exposed to gamma rays (irradiation intensity 0.809 kGy / h) for 2 hours to generate a hydrophilic crystalline covalent organic framework compound (Py-BTγ-COF) in the organic solution. The structure of this hydrophilic Py-BTγ-COF is shown in Figure 3, wherein the Py-BTγ-COF group body 11 is surrounded by multiple hydroxyl groups. group)12, which makes the Py-BTγ-COF group body 11 hydrophilic.

[0027] The actual steps of the first embodiment of the present invention are as follows: 30 mg of the solid of the crystalline covalent organic framework compound (Py-BT COF) is taken and dispersed in a mixture of o-dichlorobenzene / n-butanol to form a mixture. The mixture is purged with argon for 5 minutes and irradiated with gamma rays at room temperature (irradiation intensity of 0.809 kGy / h, irradiation time of 2 hours). A precipitate is filtered out. The precipitate is washed with tetrahydrofuran, methanol and acetone and then vacuum dried at 120°C overnight to obtain an orange powder. The orange powder is a hydrophilic crystalline covalent organic framework compound (Py-BT γ-COF(A)).

[0028] Please refer to Figure 2, which is a flowchart of the second embodiment of the present invention.

[0029] As shown in Figure 2, the method of the present invention for enhancing the hydrophilicity of a covalent organic framework by gamma ray irradiation includes:

[0030] Step S21: Add 4,4'-(benzo[c][1,2,5]thiadiazole-4,7-diyl)dibenzaldehyde and 4,4',4'',4'''-(pyrene-1,3,6,8-tetrayl)tetraphenylamine to an organic solvent to form a second solution;

[0031] Step S23: Irradiate the second solution with gamma rays to generate an amorphous covalent organic framework compound; and

[0032] Step S25: Heating the amorphous covalent organic framework compound to generate a hydrophilic crystalline covalent organic framework compound;

[0033] Figure 2 illustrates the second step of the method for enhancing the hydrophilicity of covalent organic frameworks using gamma irradiation according to the present invention. First, in step S21, 4,4'-(benzo[c][1,2,5]thiadiazole-4,7-diyl)dibenzaldehyde and 4,4',4'',4'''-(pyrene-1,3,6,8-tetrayl)tetraphenylamine are added to an organic solvent. In this embodiment, the organic solvent is a mixture of o-chlorobenzene and n-butanol (1:1, v / v). Then, in step S23, the monomer of the amorphous covalent organic framework compound is exposed to gamma rays (0.809 kGy / h) in a 20 mL glass bottle for 2 hours, thereby generating the amorphous covalent organic framework compound. The amorphous covalent organic framework compound is then transferred to a 25 mL... The reaction was carried out in a Schlenk tube at a heating temperature of 100°C to 160°C, thereby generating a hydrophilic crystalline covalent organic framework compound, namely Py-BTγ-COF as described in this embodiment, the structure of which is shown in Figure 3.

[0034] The actual steps of the second embodiment of the present invention are as follows: 4,4',4'',4'''-(pyrene-1,3,6,8-tetraphenyl)tetraphenylamine (56.67 mg, 0.1 mmol) and 4,4'-(benzo[c][1,2,5]thiadiazole-4,7-diyl)dibenzaldehyde (68.88 mg, 0.2 mmol) are dissolved in o-dichlorobenzene / n-butanol (2 mL / 2 mL), and acetic acid (6 M, 0.4 mL) is added as a catalyst to form a mixture. This mixture is transferred to a 25 mL Schlenk tube, purged with argon for 5 minutes, then the Schlenk tube is sealed and irradiated with gamma rays at room temperature (irradiation intensity 0.809 kGy / h, irradiation time 2 hours). The tube is degassed through three freeze / absorption / thaw cycles and heated at 120°C for 72 hours. After the tube was cooled to room temperature, it was opened and a precipitate was filtered out. The precipitate was washed with tetrahydrofuran, methanol and acetone, and then vacuum dried at 120°C overnight to obtain an orange powder. The orange powder is a hydrophilic crystalline covalent organic framework compound (Py-BTγ-COF(B)).

[0035] As demonstrated by the first and second embodiments above, the bisynthetic pathway involving the interaction between 4,4'-(benzo[c][1,2,5]thiadiazole-4,7-diyl)dibenzaldehyde and 4,4',4'',4'''-(pyrene-1,3,6,8-tetrayl)tetraaniline verifies the efficiency of the gamma-ray reaction in the hydrophilic COF synthesis process.

[0036] Preferably, the synthesis of 4,4'-(benzo[c][1,2,5]thiadiazole-4,7-diyl)dibenzaldehyde is described below:

[0037] Sodium carbonate (Na₂CO₃) (19.47 g, 183.6 mmol, 12.0 eq.) was dissolved in deionized water (DIH₂O) (92 mL) to prepare a 2.0 M sodium carbonate solution. (4-Formylphenyl)boronic acid (5.74 g, 38.3 mmol, 2.5 eq.) was dissolved in ethanol (50 mL) to prepare a (4-formylphenyl)boronic acid solution. The sodium carbonate solution was then bubbled with argon gas using the (4-formylphenyl)boronic acid solution for 2 hours. Degassed aqueous sodium carbonate solution and (4-formylphenyl)boric acid solution were added to 4,7-dibromobenzo[c]-1,2,5-thiadiazole (4.5 g, 15.3 mmol, 1.0 eq.) and bis(triphenylphosphine)palladium dichloride (Pd(PPh₃)₂Cl₂) (1.0 g, 1.42 mmol, 0.09 eq.) in toluene (60 mL) under argon atmosphere. After purification with argon for 30 minutes, the solution was stirred at 50°C for 24 hours. Deionized water (100 mL) was added at room temperature, the precipitate was collected by filtration, and washed successively with methanol (3 × 20 mL) and chloroform (3 × 20 mL). The pure product was recrystallized from chloroform to give 4,4'-(benzo[c][1,2,5]thiadiazole-4,7-diyl)dibenzaldehyde, a pale green solid. Formula (S1)

[0038] The synthesis of 4,4',4'',4'''-(pyrene-1,3,6,8-tetramethyl)tetraphenylamine is explained below:

[0039] In a 100 mL round-bottom flask, 1,3,6,8-tetrabromopyrene (2.0 g, 3.86 mmol), (4-aminophenyl)boronic acid (2.54 g, 18.53 mmol), tetra(triphenylphosphine)palladium (0) (452 ​​mg, 0.39 mmol), and potassium carbonate (2.95 g, 21.32 mmol) were added. The solid mixture was evacuated to subatmospheric pressure for 30 minutes. Dimethylformamide (DMF) (60 mL) and water (10 mL) were added, and the mixture was then heated at 120°C under N2 for 48 hours. After the tetrabromopyrene was exhausted, the mixture was cooled to room temperature and poured into ice water, producing a yellow-green precipitate. The solid was filtered off and washed several times with water and methanol. The separated solid Py-4NH2 was usable without further purification (80%). Formula (S2) Formula (S3)

[0040] The thermal decomposition temperature (Td10) and residual carbon content (Charyield) of the crystalline covalent organic framework compound of this invention are shown in Table 1 below. Table 1. Thermal decomposition temperatures (Td10%) and residual carbon percentages (Charyield) of the crystalline covalent organic framework compound (Py-BTCOF), the hydrophilic crystalline covalent organic framework compound of the first embodiment (Py-BTγ-COF(A)), and the hydrophilic crystalline covalent organic framework compound of the second embodiment (Py-BTγ-COF(B)). [COF] [T, d10% , (°C) ] [Charyield(%)] [Py-BTCOF] 549 70.80 [Py-BTγ-COF(A)] 530 64.21 [Py-BTγ-COF(B)] 519 54.66

[0041] The results of the comparison between the compound states and hydrogen evolution reaction rates of the present invention and existing crystalline phase covalent organic framework compounds are summarized in Table 2. Table 2 Comparison of Photocatalytic Efficiency of Crystalline Covalent Organic Framework Compounds Crystalline covalent organic framework compounds compound state Hydrogen evolution reaction (HER) (µmol h⁻¹ g⁻¹) References N 3-COF Water / TEOA / Pt 1,703 Nat. Commun.

[2015] , 6, 1-9. TP-BDDA Water / TEOA / Pt 324 ± 10 J. Am. Chem. Soc.

[2018] , 140, 1423 Py-ClTP-BT-COF Water / AA, Pt 8,875 Angew. Chem. Int. Ed.

[2020] , 59, 16902 BT-TAPT-COF Water / AA, Pt 949 Chem. Commun.

[2020] , 83 12612-12615 BtCOF150 Water / TEOA / Pt 750±25 J. Am. Chem. Soc. 2020, 142, 9752-9762 TFPT-COF Water / TEOA / Pt 1970 Chem. Sci., 2014, 5, 2789-2793 PTP-COF Water / TEOA / Pt 83 Faraday Discuss. 2017, 201, 247–264 A-TEBPY COF Water / TEOA / Pt 98 Adv. Energy Mater. 2018, 8, 1870107. FS-COF Water / AA, Pt 10100 Nat. Chem. 2018, 10, 1180-1189 sp 2 c-COF ERDN Water / TEOA / Pt 2120 Chem. 2019, 5 (6), 1632-1647 BT-COF Water / AA, Pt 76 Angew. Chem., Int. Ed. 2019, 58, 18290-18294. TP-COF Water / AA, Pt 265 Angew. Chem., Int. Ed. 2019, 58, 18290-18294. Pt-PVP-TPCOF Water / AA, Pt 8420 Angew. Chem., Int. Ed. 2019, 58, 18290-18294. TpDTz COF Water / TEOA / Pt 23 J. Am. Chem. Soc. 2019, 141, 11082-11092 TpPa COF NO 2 Water / sodium ascorbate, Pt 220 ChemCatChem 2019, 11, 2313–2319 TpPa COF Water / sodium ascorbate, Pt 1560 ChemCatChem 2019, 11, 2313–2319 TpPa COF (CH 3) 2 Water / sodium ascorbate, Pt 8330 ChemCatChem 2019, 11, 2313–2319 Py-BT COF Py-BT γ-COF(A) Py-BT γ-COF(B) Water / AA, Pt 1,380 16,279 24,707 This invention

[0042] As shown in Table 2, the hydrogen yields of the hydrophilic crystalline covalent organic framework compound (Py-BT γ-COF (A)) of the first embodiment and the hydrophilic crystalline covalent organic framework compound (Py-BT γ-COF (B)) of the second embodiment are significantly higher than those of existing crystalline covalent organic framework compounds, demonstrating that the hydrophilic crystalline covalent organic framework compounds prepared by the present invention have considerable potential in the field of photocatalysis.

[0043] As shown in Figure 4, this is the first stacking method of the hydrophilic crystalline covalent organic framework compound (Py-BT γ-COF (A)) of the first embodiment of the present invention and the hydrophilic crystalline covalent organic framework compound (Py-BT γ-COF (B)) of the second embodiment, namely, AA stacking.

[0044] As shown in Figure 5, this is a second stacking method of the hydrophilic crystalline covalent organic framework compound (Py-BT γ-COF (A)) of the first embodiment of the present invention and the hydrophilic crystalline covalent organic framework compound (Py-BT γ-COF (B)) of the second embodiment, namely AB stacking.

[0045] Table 3 uses the simulation of a crystalline phase covalent organic framework compound (Py-BTCOF) as an example to illustrate the corresponding lattice data. Table 3 shows the atomic coordinates obtained from simulating Py-BT COF in AA stacking mode. [Spatial Group] [:] [P 1 (Triclinic)] [Lattice parameters] [:] [a = 50.4387 Å, b = 42.7537 Å, and c = 3.8395 Å , , α = γ = 90.0000°, and β = 84.1065° ] [Lattice constant] [(] [Pawley Refinement] [)] [:] [R, wp =3.11%, R p =2.22% [atom] [X] [Y] [Z] atom [X] [Y] [Z] C1 -0.44724 -1.01961 -0.9293 C43 -0.64589 -0.82155 -0.80431 C2 -0.44729 -0.9901 -0.92836 C44 -0.64502 -0.79193 -0.88398 C3 -0.47221 -0.97282 -0.89356 C45 -0.66859 -0.77402 -0.8691 C4 -0.49769 -0.98742 -0.88078 C46 -0.69392 -0.78507 -0.77357 C5 -0.49764 -1.01861 -0.88177 C47 -0.69463 -0.81478 -0.69038 C6 -0.47211 -1.03508 -0.89553 C48 -0.67113 -0.83267 -0.70703 C7 -0.52327 -0.97095 -0.8706 C49 -0.71894 -0.76581 -0.77051 C8 -0.54834 -0.98642 -0.88297 C50 -0.7234 -0.74396 -1.0091 C9 -0.54829 -1.01592 -0.88391 C51 -0.74708 -0.72492 -1.01494 C10 -0.52317 -1.03322 -0.87257 C52 -0.76806 -0.72631 -0.78281 C11 -0.47248 -0.94202 -0.8876 C53 -0.76449 -0.74874 -0.52787 C12 -0.49781 -0.92667 -0.87732 C54 -0.74019 -0.76826 -0.52184 C13 -0.52305 -0.94018 -0.86514 N55 -0.78181 -0.75371 -0.2743 C14 -0.52285 -1.06401 -0.86906 S56 -0.76823 -0.78089 -0.04968 C15 -0.49756 -1.07936 -0.88215 N57 -0.73993 -0.78733 -0.26361 C16 -0.47228 -1.06585 -0.89151 C58 -0.79228 -0.70593 -0.7981 C17 -0.44666 -1.08453 -0.89023 C59 -0.78925 -0.67702 -0.90328 C18 -0.54829 -1.08083 -0.84532 C60 -0.8117 -0.65763 -0.93054 C19 -0.54856 -0.9215 -0.84028 C61 -0.83806 -0.66667 -0.85164 C20 -0.44692 -0.92521 -0.88518 C62 -0.84138 -0.69524 -0.74477 C21 -0.55406 -0.89903 -1.0773 C63 -0.8188 -0.71463 -0.71732 C22 -0.57734 -0.88072 -1.05304 C64 -0.86259 -0.64614 -0.87884 C23 -0.59607 -0.88428 -0.78768 N65 -0.37446 -1.13903 -0.86576 C24 -0.59095 -0.90702 -0.55356 C66 -0.37476 -1.16618 -0.93709 C25 -0.56748 -0.92501 -0.57687 C67 -0.34967 -1.18478 -0.94042 C26 -0.56723 -1.07592 -0.58164 C68 -0.35144 -1.21448 -1.01392 C27 -0.59065 -1.0922 -0.55942 C69 -0.3279 -1.23252 -1.01877 C28 -0.59569 -1.11459 -0.79497 C70 -0.30171 -1.22152 -0.95006 C29 -0.57695 -1.11953 -1.0606 C71 -0.30003 -1.19159 -0.87882 C30 -0.55372 -1.10291 -1.08375 C72 -0.32353 -1.17362 -0.87322 C31 -0.44341 -1.10705 -1.1312 C73 -0.27705 -1.24129 -0.94602 C32 -0.42001 -1.1254 -1.12828 C74 -0.27789 -1.26943 -0.82701 C33 -0.3989 -1.12185 -0.88103 C75 -0.25476 -1.28917 -0.82014 C34 -0.4018 -1.09907 -0.6428 C76 -0.22901 -1.28226 -0.93169 C35 -0.42536 -1.08105 -0.64487 C77 -0.22691 -1.25314 -1.05797 C36 -0.42561 -0.93023 -0.6401 C78 -0.25066 -1.23288 -1.06528 C37 -0.40211 -0.91393 -0.63694 N79 -0.20425 -1.24191 -1.18479 C38 -0.39928 -0.89137 -0.87374 S80 -0.21264 -1.20853 -1.30186 C39 -0.4204 -0.88629 -1.12072 N81 -0.2452 -1.20703 -1.19771 C40 -0.44374 -0.90295 -1.12475 C82 -0.20551 -1.30361 -0.9212 N41 -0.6203 -0.86715 -0.75066 C83 -0.21004 -1.33326 -0.98049 C42 -0.62079 -0.84002 -0.82305 C84 -0.18856 -1.35391 -0.96281 C85 -0.16171 -1.34543 -0.88526 H138 -0.42812 -0.97922 -0.96174 C86 -0.15688 -1.31606 -0.82793 H139 -0.56777 -0.97413 -0.89859 C87 -0.17847 -1.29538 -0.84633 H140 -0.56769 -1.0268 -0.90026 C88 -0.13822 -1.3673 -0.86528 H141 -0.49778 -0.90314 -0.8635 N89 -0.37489 -0.87597 -0.85743 H142 -0.49745 -1.1029 -0.86982 C90 -0.37528 -0.8488 -0.92705 H143 -0.54008 -0.89629 -1.28765 C91 -0.35024 -0.83203 -0.92926 H144 -0.58154 -0.86415 -1.24671 C92 -0.35211 -0.8022 -1.00088 H145 -0.60554 -0.90991 -0.35036 C93 -0.32863 -0.78588 -1.00464 H146 -0.56359 -0.94196 -0.38743 C94 -0.3024 -0.79878 -0.93669 H147 -0.56339 -1.05924 -0.39114 C95 -0.30062 -0.82882 -0.86734 H148 -0.60525 -1.08824 -0.356 C96 -0.32407 -0.84509 -0.86283 H149 -0.5811 -1.13581 -1.2553 C97 -0.2778 -0.78081 -0.93145 H150 -0.53974 -1.10669 -1.29431 C98 -0.27874 -0.75259 -0.81066 H151 -0.45928 -1.10977 -1.32837 C99 -0.25567 -0.73454 -0.8026 H152 -0.41764 -1.14198 -1.32496 C100 -0.22989 -0.74333 -0.91463 H153 -0.3854 -1.09617 -0.45385 C101 -0.22769 -0.77261 -1.04277 H154 -0.42747 -1.06407 -0.45242 C102 -0.25138 -0.79114 -1.05131 H155 -0.42766 -0.94705 -0.44872 N103 -0.20499 -0.78551 -1.17036 H156 -0.38569 -0.91801 -0.44821 S104 -0.21327 -0.81829 -1.28952 H157 -0.41808 -0.8699 -1.31636 N105 -0.24584 -0.8174 -1.18539 H158 -0.45962 -0.89908 -1.32171 C106 -0.20646 -0.72369 -0.90286 H159 -0.60217 -0.82903 -0.90085 C107 -0.21108 -0.69371 -0.96025 H160 -0.62561 -0.78288 -0.95607 C108 -0.18967 -0.67462 -0.94132 H161 -0.66728 -0.75106 -0.92505 C109 -0.16279 -0.68506 -0.86436 H162 -0.71386 -0.82375 -0.61402 C110 -0.15787 -0.71478 -0.80891 H163 -0.67181 -0.85557 -0.64548 C111 -0.17938 -0.73389 -0.82856 H164 -0.70851 -0.74151 -1.20964 C112 -0.13937 -0.66489 -0.84306 H165 -0.7489 -0.709 -1.21957 N113 -0.61987 -1.12995 -0.75898 H166 -0.76884 -0.66954 -0.95768 C114 -0.62027 -1.15706 -0.83308 H167 -0.80912 -0.63534 -1.00974 C115 -0.64531 -1.17369 -0.81545 H168 -0.86177 -0.70239 -0.68318 C116 -0.64435 -1.20338 -0.897 H169 -0.82175 -0.73665 -0.63329 C117 -0.66787 -1.21958 -0.8832 H170 -0.88221 -0.65614 -0.80745 C118 -0.69324 -1.20667 -0.78691 H171 -0.39408 -1.17713 -0.99638 C119 -0.69404 -1.1769 -0.70184 H172 -0.37145 -1.2234 -1.07024 C120 -0.67059 -1.16073 -0.71741 H173 -0.3297 -1.25529 -1.08383 C121 -0.71819 -1.22412 -0.78501 H174 -0.28009 -1.18258 -0.82683 C122 -0.72258 -1.24566 -1.02497 H175 -0.32218 -1.15068 -0.81616 C123 -0.7462 -1.26298 -1.03196 H176 -0.29701 -1.27682 -0.72419 C124 -0.76719 -1.26003 -0.7997 H177 -0.25749 -1.31054 -0.71283 C125 -0.76369 -1.23785 -0.54335 H178 -0.23062 -1.34004 -1.04852 C126 -0.73945 -1.2201 -0.53614 H179 -0.19222 -1.37669 -1.01101 N127 -0.78103 -1.23159 -0.28942 H180 -0.13611 -1.30933 -0.76795 S128 -0.76753 -1.2054 -0.06311 H181 -0.17433 -1.27273 -0.80222 N129 -0.73925 -1.20103 -0.2767 H182 -0.11804 -1.35758 -0.8026 C130 -0.79135 -1.27866 -0.81622 H183 -0.39464 -0.83644 -0.9856 C131 -0.78822 -1.3078 -0.92324 H184 -0.37215 -0.79182 -1.05659 C132 -0.81061 -1.32555 -0.95167 H185 -0.33051 -0.76297 -1.06825 C133 -0.837 -1.31459 -0.87214 H186 -0.28065 -0.83929 -0.81597 C134 -0.84041 -1.28576 -0.76345 H187 -0.32264 -0.86813 -0.80722 C135 -0.8179 -1.26801 -0.73483 H188 -0.29788 -0.7438 -0.70732 C136 -0.86147 -1.33333 -0.90058 H189 -0.25847 -0.71295 -0.69392 H137 -0.42804 -1.03189 -0.9634 H190 -0.23169 -0.68544 -1.02781 H191 -0.19341 -0.65158 -0.98807 H235 -0.04703 -0.62105 -0.90293 H192 -0.13707 -0.72302 -0.7494 C236 -0.0471 -0.56701 -0.6284 H193 -0.17517 -0.75684 -0.7859 C237 -0.04519 -0.53825 -0.75204 H194 -0.11916 -0.67608 -0.78104 C238 -0.02562 -0.57887 -0.42343 H195 -0.60161 -1.16941 -0.91162 C239 -0.0217 -0.52186 -0.65792 H196 -0.6249 -1.21386 -0.96971 C240 -0.0654 -0.52526 -0.98304 H197 -0.66648 -1.24265 -0.9406 H241 -0.02762 -0.60059 -0.32214 H198 -0.7133 -1.16652 -0.62486 H242 -0.08228 -0.53819 -1.07392 H199 -0.67135 -1.13777 -0.65441 N243 -0.86317 -0.61925 -0.97278 H200 -0.70768 -1.2492 -1.22571 C244 -0.88792 -0.60257 -0.97045 H201 -0.74797 -1.27877 -1.2376 C245 -0.91377 -0.61352 -1.05911 H202 -0.76778 -1.31677 -0.97815 C246 -0.88647 -0.57297 -0.88754 H203 -0.80796 -1.34804 -1.03229 C247 -0.93733 -0.59544 -1.0581 H204 -0.86083 -1.27712 -0.70136 H248 -0.9152 -0.63599 -1.14001 H205 -0.82092 -1.24577 -0.6494 C249 -0.91015 -0.55514 -0.88288 H206 -0.88112 -1.32189 -0.82852 H250 -0.86647 -0.56448 -0.82173 N207 -0.13906 -1.39506 -0.91119 C251 -0.93612 -0.56594 -0.96968 C208 -0.11497 -1.41269 -0.88033 H252 -0.95706 -0.60414 -1.13356 C209 -0.08897 -1.40425 -0.9863 H253 -0.90861 -0.53251 -0.80922 C210 -0.11734 -1.4408 -0.74874 C254 -0.96174 -0.54732 -0.9589 C211 -0.06611 -1.42321 -0.95462 C255 -0.96483 -0.52038 -1.13327 H212 -0.08689 -1.38313 -1.10409 C256 -0.98346 -0.55668 -0.76261 C213 -0.09436 -1.45949 -0.71403 C257 -0.94435 -0.51024 -1.35846 H214 -0.13746 -1.44737 -0.66954 C258 -0.98975 -0.50314 -1.09821 C215 -0.06824 -1.45118 -0.81774 H259 -0.98063 -0.57693 -0.62258 H216 -0.04628 -1.41652 -1.04394 H260 -0.92627 -0.52405 -1.40489 H217 -0.09658 -1.48084 -0.60311 N261 -0.86196 -1.36019 -0.99622 C218 -0.04333 -1.4707 -0.77605 C262 -0.88578 -1.37607 -0.95682 C219 -0.04196 -1.49952 -0.90479 C263 -0.88238 -1.40576 -0.88005 C220 -0.02056 -1.46018 -0.59647 C264 -0.9127 -1.36424 -1.00314 C221 -0.01761 -1.51735 -0.8417 C265 -0.90509 -1.42282 -0.84022 C222 -0.06368 -1.51123 -1.1114 H266 -0.86159 -1.41493 -0.84703 H223 -0.02207 -1.43836 -0.491 C267 -0.93533 -1.38155 -0.96696 H224 -0.08135 -1.49729 -1.17973 H268 -0.9158 -1.34168 -1.07875 N225 -0.1403 -0.63707 -0.88721 C269 -0.93208 -1.41115 -0.88445 C226 -0.1168 -0.62085 -0.82547 H270 -0.90195 -1.44554 -0.77184 C227 -0.12067 -0.59259 -0.69499 H271 -0.95594 -1.37217 -1.01033 C228 -0.08988 -0.63082 -0.89958 C272 -0.95664 -1.42893 -0.8355 C229 -0.09833 -0.57523 -0.63058 C273 -0.96043 -1.45572 -1.00733 H230 -0.14148 -0.58482 -0.64044 C274 -0.9765 -1.41893 -0.60512 C231 -0.06764 -0.61319 -0.8382 C275 -0.94205 -1.46648 -1.26474 H232 -0.0865 -0.65207 -1.01573 C276 -0.98407 -1.47219 -0.93516 C233 -0.0713 -0.58509 -0.70243 H277 -0.97305 -1.39879 -0.46801 H234 -0.10177 -0.55373 -0.52134 H278 -0.92514 -1.45324 -1.33776

[0046] As shown in Figure 6, the crystallinity of the non-hydrophilic crystalline covalent organic framework compound (Py-BTCOF) was measured by powder X-ray diffraction (PXRD) compared to the hydrophilic crystalline covalent organic framework compound (Py-BTγ-COF(A)) of the first embodiment and the hydrophilic crystalline covalent organic framework compound (Py-BTγ-COF(B)) of the second embodiment. The PXRD patterns of the three COFs show prominent peaks at angles of 2.77, 3.77, 5.60, 8.35, and 11.11 degrees, distributed on the (110), (200), (220), and (330) planes. The weak and broad peak at 23.97 degrees indicates the presence of π-π packing in the two-dimensional COF crystal.

[0047] The results obtained using field emission scanning electron microscopy (FE-SEM) are shown in Figures 7A to 8B, and the results obtained using transmission electron microscopy (TEM) are shown in Figures 9A to 10B.

[0048] The crystallization state diagrams of the non-hydrophilic crystalline covalent organic framework compound (Py-BT COF) of the present invention at different magnifications in SEM images are shown in Figures 7A and 7B; the crystallization state diagrams of the hydrophilic crystalline covalent organic framework compound (Py-BTγ-COF(A)) of the first embodiment and the hydrophilic crystalline covalent organic framework compound (Py-BTγ-COF(B)) of the second embodiment at different magnifications in SEM images are shown in Figures 8A and 8B.

[0049] The crystallization state diagrams of the non-hydrophilic crystalline covalent organic framework compound (Py-BTCOF) of the present invention at different magnifications in TEM images are shown in Figures 9A and 9B; the crystallization state diagrams of the hydrophilic crystalline covalent organic framework compound (Py-BTγ-COF(A)) of the first embodiment and the hydrophilic crystalline covalent organic framework compound (Py-BTγ-COF(B)) of the second embodiment at different magnifications in TEM images are shown in Figures 10A and 10B.

[0050] The results in Figures 7A to 10B above show that the SEM and TEM images of the non-hydrophilic crystalline covalent organic framework compound (Py-BTCOF) exhibit a rod-like morphology, indicating poor contact with water molecules. In contrast, the hydrophilic crystalline covalent organic framework compound (Py-BTγ-COF(A)) of the first embodiment and the hydrophilic crystalline covalent organic framework compound (Py-BTγ-COF(B)) of the second embodiment exhibit a spherical crystal shape, which facilitates contact with water molecules from multiple directions, thereby accelerating hydrogen production.

[0051] In addition, the thermal stability of the products of each embodiment was determined by thermogravimetric analysis (TGA) by recording the weight change with temperature. The results are shown in Table 1. The decomposition temperatures (Td10) of Py-BTCOF, Py-BTγ-COF(A) and Py-BTγ-COF(B) are 549, 530 and 519°C, respectively, showing that the crystalline covalent organic framework compounds have good thermal stability under nitrogen atmosphere.

[0052] As shown in Figures 11A and 11B, the hydrophilicity results of the non-hydrophilic crystalline covalent organic framework compound (Py-BT COF) of the present invention compared with the hydrophilic crystalline covalent organic framework compound (Py-BT γ-COF (A)) of the first embodiment and the hydrophilic crystalline covalent organic framework compound (Py-BT γ-COF (B)) of the second embodiment can be determined by measuring the contact angle of water droplets W dropped onto the thin films formed by each organic framework compound. The results show that when water droplet W is applied to the first thin film 20 made of a non-hydrophilic crystalline phase covalent organic framework compound (Py-BT COF), the edge of the water droplet forms a 121-degree angle with the plane of the first thin film 20 due to the poor hydrophilicity of the first thin film 20. However, when water droplet W is applied to the second thin film 30 made of a hydrophilic crystalline phase covalent organic framework compound (Py-BT γ-COF (B)) in the second embodiment, the edge of the water droplet forms a 22-degree angle with the plane of the second thin film 30 due to the better hydrophilicity of the second thin film 30. Therefore, the hydrophilic crystalline phase covalent organic framework compound of the present invention exhibits superior hydrophilic properties compared to existing crystalline phase covalent organic framework compounds.

[0053] As shown in Figure 12A, the ultraviolet-visible light spectrum of the crystalline covalent organic framework compound of the present invention is presented. The hydrophilic crystalline covalent organic framework compound (Py-BT γ-COF (A)) of the first embodiment and the hydrophilic crystalline covalent organic framework compound (Py-BT γ-COF (B)) of the second embodiment of the present invention show a greater redshift compared to the non-hydrophilic crystalline covalent organic framework compound (Py-BT COF). This can be explained by the hydrophilic groups in the crystalline covalent organic framework compound obtained after gamma radiation modification. Due to the presence of intramolecular hydrogen bonds (OH···N=C) in the structure of the crystalline covalent organic framework compound, the light absorption range is enhanced to 620 nm. This phenomenon shows that the crystalline covalent organic framework compound modified by gamma radiation has a stronger visible light absorption capacity.

[0054] As shown in Figure 12B, this is a result diagram of the optical band gap difference of the crystalline covalent organic framework compound of the present invention. Based on the Tauc plots corresponding to the non-hydrophilic crystalline covalent organic framework compound (Py-BT COF) of the present invention, the hydrophilic crystalline covalent organic framework compound (Py-BT γ-COF (A)) of the first embodiment, and the hydrophilic crystalline covalent organic framework compound (Py-BT γ-COF (B)) of the second embodiment, the calculated optical band gap differences are 2.50, 1.95, and 1.90 eV, respectively. It can be clearly seen that after gamma radiation modification, the range of the optical band gap difference of the hydrophilic crystalline covalent organic framework compound is significantly reduced.

[0055] As shown in Figure 12C, this is a schematic diagram of the LUMO energy levels of the crystalline covalent organic framework compounds of the present invention. The LUMO energy levels of the non-hydrophilic crystalline covalent organic framework compound (Py-BT COF) of the present invention, the hydrophilic crystalline covalent organic framework compound (Py-BT γ-COF (A)) of the first embodiment, and the hydrophilic crystalline covalent organic framework compound (Py-BT γ-COF (B)) of the second embodiment were determined to be -3.28, -3.60, and -3.35 eV, respectively.

[0056] As shown in Figure 13A, this figure illustrates the hydrogen production results of the crystalline covalent organic framework compound of the present invention. Through hydrogen evolution reaction (HER), the hydrophilic crystalline covalent organic framework compound (Py-BT γ-COF (A)) of the first embodiment and the hydrophilic crystalline covalent organic framework compound (Py-BT γ-COF (B)) of the second embodiment of the present invention showed an increase in hydrogen production of 11.8 times and 18.0 times, respectively, in the visible light absorption range of 380-780 nm, compared to the non-hydrophilic crystalline covalent organic framework compound (Py-BT COF) of the present invention. Therefore, the non-hydrophilic crystalline covalent organic framework compound (Py-BT COF) of the present invention, after being modified by gamma ray irradiation, optimizes the hydrophilicity of the material, thereby improving the photocatalytic hydrogen evolution effect.

[0057] In the field of photocatalysis research, standardized reaction rates are typically used to measure the catalytic activity of catalysts. However, for the same photocatalytic reaction system, excessive addition of catalyst can affect the penetration depth of incident light and the degree of scattering of incident light by the catalyst, leading to a decrease in catalytic activity with increasing catalyst dosage. Therefore, in heterogeneous photocatalytic systems, the "apparent quantum yield" (AQY), calculated by the ratio of the number of electrons participating in the reaction to the total number of incident photons, represents the efficiency of hydrogen production in the photocatalytic reaction.

[0058] As shown in Figure 13B, this figure illustrates the apparent quantum yield of hydrogen release from the crystalline covalent organic framework compound of the present invention at different wavelengths. Compared to the non-hydrophilic crystalline covalent organic framework compound (Py-BT COF) of the present invention, the hydrophilic crystalline covalent organic framework compound (Py-BT γ-COF (A)) of the first embodiment and the hydrophilic crystalline covalent organic framework compound (Py-BT γ-COF (B)) of the second embodiment exhibit significantly higher hydrogen production efficiency after gamma ray irradiation at visible light absorption wavelengths of 420 nm, 460 nm, and 500 nm.

[0059] As shown in Figure 13C, this figure illustrates the long-term hydrogen production performance of the hydrophilic crystalline covalent organic framework compound of the present invention combined with a photocatalyst under visible light catalysis. In the second embodiment of the present invention, the hydrophilic crystalline covalent organic framework compound (Py-BT γ-COF (B)) was photocatalyzed under visible light. The hydrogen concentration emitted by the hydrophilic crystalline covalent organic framework compound (Py-BT γ-COF (B)) of the second embodiment of the present invention showed a linear relationship with time. This indicates that the crystalline covalent organic framework compound modified by gamma ray irradiation, combined with the addition of a photocatalyst, enables the hydrophilic crystalline covalent organic framework compound of the present invention to possess excellent long-term hydrogen production performance.

[0060] In summary, the method of enhancing the hydrophilicity of covalent organic frameworks using gamma irradiation according to the present invention, after irradiating the non-hydrophilic crystalline phase covalent organic framework compound prepared by 4,4'-(benzo[c][1,2,5]thiadiazole-4,7-diyl)dibenzaldehyde and 4,4',4'',4'''-(pyrene-1,3,6,8-tetraphenyl)tetraphenylamine with gamma rays, results in a product with significantly enhanced hydrophilicity and excellent hydrogen evolution reaction rate, which is beneficial as a photocatalyst for hydrogen generation.

[0061] Therefore, this invention is indeed novel, inventive, and industrially applicable, and undoubtedly meets the requirements for patent application under the Patent Law of our country. Thus, we hereby file an invention patent application in accordance with the law, and earnestly pray that the Bureau will grant the patent as soon as possible.

[0062] However, the above description is only a preferred embodiment of the present invention and is not intended to limit the scope of the present invention. All equivalent changes and modifications made to the shape, structure, features and spirit described in the claims of the present invention should be included in the scope of the claims of the present invention.

[0063] 10: Hydrophilic crystalline covalent organic framework compounds 11: Hydrophilic crystalline phase covalent organic framework compound group body 12: Hydroxyl group 20: First Thin Film 30: Second thin film W: Water Drop S11~S15: Steps S21~S25: Steps

Claims

1. A method for enhancing the hydrophilicity of a covalent organic framework using gamma irradiation, comprising the steps of: adding 4,4'-(benzo[c][1,2,5]thiadiazole-4,7-diyl)dibenzaldehyde and 4,4',4'',4'''-(pyrene-1,3,6,8-tetrayl)tetraphenylamine, adding a catalyst, and heating to generate a crystalline covalent organic framework compound; adding the dried crystalline covalent organic framework compound to an organic solvent to form a first solution; and irradiating the first solution with gamma rays to generate a hydrophilic crystalline covalent organic framework compound, wherein the crystalline covalent organic framework compound is Py-BT γ-COF, and its structural formula is [insert structural formula here].

2. The method for enhancing the hydrophilicity of a covalent organic framework by gamma irradiation as described in claim 1, wherein the catalyst comprises acetic acid.

3. The method for enhancing the hydrophilicity of a covalent organic framework using gamma irradiation as described in claim 1, wherein the heating temperature is 100°C to 160°C in the steps of adding a catalyst and heating to generate a crystalline covalent organic framework compound.

4. The method for enhancing the hydrophilicity of a covalent organic framework by gamma irradiation as described in claim 1, wherein the organic solvent comprises o-chlorobenzene and n-butanol.

5. The method for enhancing the hydrophilicity of a covalent organic framework by gamma irradiation as described in claim 1, wherein the irradiation intensity of the gamma rays is 0.809 k Gy / h and the irradiation time of the gamma rays is 2 hours.

6. A method for enhancing the hydrophilicity of a covalent organic framework using gamma ray irradiation, comprising the steps of: adding 4,4'-(benzo[c][1,2,5]thiadiazole-4,7-diyl)dibenzaldehyde and 4,4',4'',4'''-(pyrene-1,3,6,8-tetraphenyl)tetraphenylamine to an organic solvent to form a second solution; irradiating the second solution with gamma rays to generate an amorphous covalent organic framework compound; and heating the amorphous covalent organic framework compound to generate a hydrophilic crystalline covalent organic framework compound; wherein, The covalent organic framework compound of this crystalline phase is Py-BT γ-COF, and its structural formula is [insert structural formula here].

7. The method for enhancing the hydrophilicity of a covalent organic framework by gamma irradiation as described in claim 6, wherein the heating temperature in the step of heating the amorphous covalent organic framework compound is 100°C to 160°C.

8. The method for enhancing the hydrophilicity of a covalent organic framework by gamma irradiation as described in claim 6, wherein the organic solvent comprises o-chlorobenzene and n-butanol.

9. The method for enhancing the hydrophilicity of a covalent organic framework by gamma irradiation as described in claim 6, wherein the irradiation intensity of the gamma rays is 0.809 kGy / h and the irradiation time of the gamma rays is 2 hours.

Images