A proton-conducting organic porous membrane catalyst and its preparation method and application
By designing a proton-conducting organic porous membrane catalyst, the problem of separating hydrogen and oxygen in photocatalytic water splitting was solved, achieving efficient automatic separation of hydrogen and oxygen, improving the efficiency and rate of photocatalytic water splitting, and making it suitable for industrial applications.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- FUJIAN INST OF RES ON THE STRUCTURE OF MATTER CHINESE ACAD OF SCI
- Filing Date
- 2023-10-11
- Publication Date
- 2026-06-16
AI Technical Summary
In existing photocatalytic water splitting technologies, the separation of hydrogen and oxygen is difficult, and the types of highly efficient photocatalysts are limited, which hinders the commercial development of photocatalytic water splitting technologies.
A proton-conducting organic porous membrane catalyst is designed, comprising an organic porous thin film material and a Nafion membrane. The catalyst components are a covalent organic framework and a conjugated microporous polymer, which have light-harvesting, charge-separation and proton-conducting properties. Oxygen evolution and hydrogen evolution co-catalysts are deposited on both sides of the membrane to achieve automatic separation of hydrogen and oxygen.
It achieves efficient separation and production of hydrogen and oxygen, improves the efficiency and rate of photocatalytic reaction, simplifies the process, reduces costs, and is suitable for industrial application.
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Figure CN117599846B_ABST
Abstract
Description
Technical Field
[0001] This application relates to a proton-conducting organic porous membrane catalyst, its preparation method, and its application, belonging to the field of photocatalysis technology. Specifically, it relates to a method for preparing an organic porous thin-film photocatalyst that combines light capture, charge separation, and proton conduction characteristics, and its application in the photocatalytic total water splitting process for hydrogen and oxygen separation. Background Technology
[0002] In recent years, the massive consumption of fossil fuels has not only triggered an energy crisis, but the large amounts of byproducts emitted from their combustion have also exacerbated increasingly severe global warming and air pollution. Photocatalytic water splitting is a promising solar-powered hydrogen and oxygen production technology that can provide solutions to energy and environmental issues. In the process of photocatalytic water splitting, water is oxidized to oxygen by holes, producing protons, which are then reduced by electrons to produce hydrogen. Because this process generates both hydrogen and oxygen, traditional photocatalytic water splitting technologies require further separation of hydrogen and oxygen for gas purification and to avoid safety issues caused by mixed gases. Furthermore, the high requirements for photocatalysts (e.g., needing to possess both oxygen catalytic oxidation and catalytic reduction sites, light capture, and charge separation functions) limit the variety of existing functionalized, high-efficiency photocatalysts. Therefore, the additional gas separation step and relatively low photocatalytic efficiency hinder the commercialization of photocatalytic water splitting technology.
[0003] Currently, thin-film photocatalysts have attracted much attention. Thin-film photocatalysts typically possess high specific surface areas, providing more catalytic active sites and higher light absorption efficiency. Furthermore, the catalytic performance of thin-film photocatalysts can be tuned by adjusting parameters such as composition and structure, enabling their application in various catalytic reactions under different conditions. In addition, thin-film photocatalysts generally exhibit good chemical and photostability, maintaining catalytic performance under prolonged illumination. In particular, ultrathin two-dimensional thin-film photocatalysts can provide more catalytic active centers and allow more charge carriers to diffuse to the interface for redox reactions, thereby enhancing the efficiency and rate of photocatalytic reactions. Two-dimensional thin-film photocatalysts based on organic porous membranes, due to their highly ordered pore structure and tunable charge transport properties, can utilize efficient charge separation and effective interfacial contact to improve overall photocatalytic reaction efficiency. Simultaneously, introducing proton-loving groups onto organic porous materials can improve proton conductivity, thereby better linking oxygen evolution and hydrogen evolution reactions. However, the application of organic porous membrane catalysts in photocatalytic water splitting is still rarely reported; moreover, how to achieve the automatic separation and production of hydrogen and oxygen during water splitting based on organic porous membrane catalysts remains unsolved.
[0004] Therefore, the design and preparation of organic porous membrane catalysts with special structures and functions, as well as the design and development of photocatalytic total water splitting systems for hydrogen and oxygen separation, have become key challenges. Effectively addressing these challenges is of great significance for achieving low-cost and efficient photocatalytic total water splitting processes. Summary of the Invention
[0005] According to one aspect of this application, a proton-conducting organic porous membrane catalyst is provided, which combines light capture, charge separation and proton conduction properties.
[0006] The technical solution adopted in this application is as follows:
[0007] A proton-conducting organic porous membrane catalyst, wherein the proton-conducting organic porous membrane catalyst comprises an organic porous thin film material;
[0008] The organic porous thin film material includes a catalyst component and a Nafion membrane;
[0009] The catalyst component is selected from at least one of covalent organic frameworks (COF), conjugated microporous polymers (CMP), and self-microporous polymers.
[0010] The organic porous thin film material includes an electron donor and an electron acceptor.
[0011] Optionally, when the catalyst component is a covalent organic framework, the sulfonated polymer in the Nafion membrane encapsulates the covalent organic framework.
[0012] Covalent organic framework thin films, also known as covalent organic framework (COF) thin films, possess photoresponsiveness, exhibit charge separation capabilities through the presence of donors and acceptors, and also demonstrate hydrogen proton conduction capabilities.
[0013] Optionally, when the electron donor is monomer A, the electron acceptor is monomer B; when the electron donor is monomer B, the electron acceptor is monomer A.
[0014] Optionally, monomer A contains 2 to 4 amino links;
[0015] Optionally, the monomer B contains 2 to 4 aldehyde group connectors;
[0016] Optionally, the monomer A is selected from at least one of the following structural formulas:
[0017]
[0018] Optionally, the monomer A is selected from at least one of 3,7-diamino-dibenzothiophene sulfone, 2,7-diamino-9H-fluorene-9-one, 3,7-diamino-2,8-dimethyl-dibenzothiophene sulfone, N,N,N',N'-tetra(p-aminophenyl)p-phenylenediamine, p-phenylenediamine-2,5-disulfonic acid, p-phenylenediamine-2,5-dicarboxylic acid, and 5,10,15,20-tetra(4-aminophenyl)-21H,23H-porphyrin.
[0019] Optionally, 3,7-diamino-dibenzothiophene sulfone has the structure shown in formula (1).
[0020]
[0021] Optionally, the monomer B is selected from at least one of the following structural formulas:
[0022]
[0023] Optionally, the monomer B is selected from at least one of 2,4,6-tricarboxyloylphloroglucinol, pyromellitic acid tricarboxaldehyde, 5,10,15,20-tetra(4-aldehydebenzene)-21H,23H-metalporphyrin, pyromellitic dianhydride, 3,4,9,10-naphthalenetetracarboxylic anhydride, and 3,4,9,10-perylenetetracarboxylic anhydride.
[0024] Optionally, 2,4,6-tricarboxymethyl phloroglucinol has the structure shown in formula (2).
[0025]
[0026] R is selected from at least one of CH3, OCH3, F, CL, and Br.
[0027] Optionally, oxygen evolution cocatalyst and hydrogen evolution cocatalyst are photodeposited in situ on both sides of the organic porous thin film material, respectively;
[0028] The oxygen evolution cocatalyst is at least one selected from IrO2, RuO2, NiO, Mn3O4, and Co3O4;
[0029] The hydrogen evolution cocatalyst is at least one of Pt, Rh, and Ag;
[0030] Optionally, the proton-conducting organic porous membrane catalyst contains at least one of sulfonic acid group, carboxyl group, hydroxyl group, metal-free porphyrin, and imine.
[0031] In proton-conducting organic porous membrane catalysts, sulfonic acid groups, carboxyl groups, hydroxyl groups, metal-free porphyrins, and imines possess hydrogen proton conduction capabilities.
[0032] According to another aspect of this application, a method for preparing the above-mentioned proton-conducting organic porous membrane catalyst is also provided, comprising the following steps:
[0033] S1. A mixture containing an electron donor, an electron acceptor, and a Nafion membrane solution is used to synthesize a precursor casting solution.
[0034] S2. The precursor casting solution obtained in step S1 is coated onto the substrate, and the film is formed by heating to form a proton-conducting organic porous membrane catalyst.
[0035] Optionally, the molar ratio of the electron donor to the electron acceptor is 1:0.6 to 2.
[0036] Optionally, the molar ratio of the electron donor and electron acceptor is selected from any value among 1:0.6, 1:1, 1:1.5, and 1:2, or any range between the two.
[0037] Optionally, the weight ratio of the total weight of the electron donor and electron acceptor to the weight of the Nafion membrane solution is 1:1 to 10.
[0038] Optionally, the weight ratio of the total weight of the electron donor and electron acceptor to the weight of the Nafion membrane solution is selected from any value among 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, and 1:10, or any range between the two.
[0039] Optionally, the concentration of the Nafion membrane solution is 5% wt.
[0040] The concepts of electron donor, monomer A, electron acceptor, and monomer B in the preparation method of this application are the same as those in the aforementioned technical solution of a proton-conducting organic porous membrane catalyst.
[0041] In the precursor casting solution, monomers B and A can generate covalent organic framework (COF) nanosheets through in-situ reaction catalyzed by sulfonic acid groups in the Nafion membrane solution, which encapsulate the sulfonated polymer in the Nafion membrane solution, thereby achieving a homogeneous casting solution without large particles.
[0042] Optionally, in step S1, the synthesis conditions include: a reaction temperature of 60–180°C and a reaction time of 12–72 h.
[0043] Optionally, in step S1, the synthesis conditions include: the reaction temperature is selected from any value of 60, 80°C, 120°C, and 180°C, or any range between two of them.
[0044] Optionally, in step S1, the synthesis conditions include: the reaction time is selected from any value of 12h, 24h, 48h, 60h, 72h, or any range between the two.
[0045] Within the above-mentioned reaction temperature range, the crystallization of organic porous thin film materials can be promoted; within the above-mentioned reaction time, the reaction can be made more complete.
[0046] Optionally, in step S2, the conditions for heating to form a film include: heating at 60-100°C with forced air for 2-6 hours, and then heating at 120-150°C for 3-12 hours.
[0047] Optionally, in step S2, the conditions for heating to form a film include: the temperature is selected from any value of 60℃, 70℃, 80℃, 90℃, and 100℃, or a range between any two.
[0048] Optionally, in step S2, the conditions for heating to form a film include: the time for blowing air heating is selected from any value among 2h, 3h, 4h, 5h, and 6h, or any range between the two.
[0049] Optionally, in step S2, the conditions for heating to form a film include: heating to any value of 120°C, 135°C, or 150°C, or a range between any two, and then heating for any value of 3h, 6h, or 12h, or a range between any two.
[0050] Optionally, in step S2, the substrate is made of at least one of hydrophilic glass, polyethylene terephthalate, polyphenylene ether sulfone, polymethyl methacrylate, and polyetherimide.
[0051] Step S2 can produce a homogeneous, tough, self-supporting covalent organic framework (COF) film.
[0052] Optionally, step S2 further includes heating to form a film and then washing the film.
[0053] Optionally, the membrane washing process includes: soaking the proton-conducting organic porous membrane catalyst in a 0.1-1M sulfuric acid solution at a temperature of 60-120°C for 1-6 hours, then transferring it to 80°C water for immersion, followed by rinsing with a large amount of water to separate the organic porous membrane from the substrate, and then allowing the organic porous membrane to air dry naturally at room temperature.
[0054] Optionally, the sulfuric acid concentration is any value among 0.1M, 0.5M, and 1M, or a range between any two.
[0055] Optionally, the sample can be immersed for 1 to 6 hours at any temperature of 60°C, 80°C, 100°C, or 120°C, or any range between two of these temperatures.
[0056] Optionally, step S1 includes:
[0057] S11. Obtain solutions containing electron donors and solutions containing electron acceptors, respectively;
[0058] S12. Add the Nafion membrane solution to a solution containing an electron donor, and then slowly add a solution containing an electron acceptor to mix and synthesize the precursor casting solution.
[0059] The solvents in the solutions containing electron donors and electron acceptors are independently selected from at least one organic solvent selected from o-dichlorobenzene, methanol, ethanol, N,N-dimethylformamide, N-methylpyrrolidone, dimethyl sulfoxide, dioxane, and tetrahydrofuran.
[0060] Optionally, the reaction conditions and environment required for the synthesis process can be achieved by any one of the following methods: hydrothermal method, solvothermal method, melting method, and vacuum sealing method.
[0061] Optionally, the synthesis is performed using a hydrothermal method.
[0062] Optionally, step S2 further includes:
[0063] After heating and forming a film, one side of the proton-conducting organic porous membrane catalyst is contacted with the aqueous solution of raw material A and an oxygen evolution co-catalyst is photodeposited in situ, while the other side is contacted with the aqueous solution of raw material B and a hydrogen evolution co-catalyst is photodeposited in situ.
[0064] Optionally, the conditions for the in-situ photodeposition include: immersing the proton-conducting organic porous membrane catalyst in an aqueous solution of the metal raw material and irradiating it with light for 0.5 to 2 hours;
[0065] Raw material A is selected from at least one of CoCl2, Co(NO3)2, MnCl2, and RuCl2;
[0066] Raw material B is selected from at least one of H2PtCl4, K2PtCl4, K2RhCl4, K2AuCl4, and AgNO3.
[0067] According to another aspect of this application, at least one of the above-described proton-conducting organic porous membrane catalysts, and the proton-conducting organic porous membrane catalysts prepared according to the above preparation method, is provided as a photocatalyst for converting solar energy into chemical energy.
[0068] Optionally, the proton-conducting organic porous membrane catalyst is sandwiched in the middle of the H-shaped double-cylinder reaction tank, so that hydrogen and oxygen self-separation occurs on both sides of the proton-conducting organic porous membrane catalyst.
[0069] Alternatively, proton-conducting organic porous membrane catalysts can be used for solar-powered hydrogen production.
[0070] In this application, the solar hydrogen production process involves depositing oxygen evolution cocatalyst and hydrogen evolution cocatalyst on both sides of the membrane to perform photocatalytic water splitting, thereby achieving the effect of hydrogen and oxygen self-separation.
[0071] Optionally, one side of the proton-conducting organic porous membrane catalyst uses Co3O4 as an oxygen evolution cocatalyst, and the other side uses Pt as a hydrogen evolution cocatalyst.
[0072] Optionally, the application also includes a system for photocatalytic total water splitting, the system having a hydrogen-oxygen self-separation system.
[0073] Optionally, a proton-conducting organic porous membrane catalyst is sandwiched in the middle of an H-shaped double-cylinder reaction tank. Under light irradiation, hydrogen is generated in the reaction tank on the side where Pt is deposited, and oxygen is generated in the reaction tank on the side where Co3O4 is deposited.
[0074] The beneficial effects that this application can produce include:
[0075] (1) The method for preparing proton-conducting organic porous membrane catalyst provided in this application is simple and does not require inert gas protection. The synthesized covalent organic framework (COF) film does not require substrate support, has strong toughness, low cost, and is suitable for industrial promotion.
[0076] (2) When the proton-conducting organic porous membrane catalyst provided in this application is used as a photocatalyst, it can achieve efficient light absorption and charge separation, and realize the directional migration of electrons and holes and high concentration of surface charge, thereby improving the overall photocatalytic activity.
[0077] (3) By photodepositing catalytic oxidation sites and catalytic reduction sites on both sides of the proton-conducting organic porous membrane catalyst provided in this application, hydrogen evolution and oxygen evolution reactions can occur on both sides of the membrane respectively, and the protons required for hydrogen evolution reaction can be efficiently transported to the hydrogen evolution side by the covalent organic framework (COF) thin film material, thereby ensuring that the two reactions occur simultaneously.
[0078] (4) Using the proton-conducting organic porous membrane catalyst provided in this application as the diaphragm of the H-type photocatalytic cell, hydrogen and oxygen are produced simultaneously and separately in the left and right reaction chambers. Attached Figure Description
[0079] Figure 1 This is a schematic diagram of the structure of the covalent organic framework material prepared from the membrane precursor casting solution of Example 1 in this application.
[0080] Figure 2 This is an X-ray powder diffraction pattern of the covalent organic framework thin film material prepared from the film precursor casting solution of Example 1 in this application.
[0081] Figure 3This is a scanning electron microscope (SEM) image of the covalent organic framework thin film material prepared from the film precursor casting solution of Example 1 in this application.
[0082] Figure 4 This is a physical image of the covalent organic framework thin film material prepared from the film precursor casting solution of Example 1 in this application.
[0083] Figure 5 The graph shows a performance comparison of the photocatalytic systems assembled in Examples 1 to 10 of this application. Detailed Implementation
[0084] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.
[0085] Unless otherwise specified, all raw materials used in the embodiments of this application were purchased through commercial channels.
[0086] The membrane solution is a Nafion membrane solution.
[0087] In this application, monomers A and B, as shown in Tables 1 and 2, are selected as raw materials for the preparation of the casting solution of the conjugated organic framework (COF) film precursor. The two-joint monomer needs to be combined with the three-joint or four-joint monomer to form the conjugated organic framework (COF) material.
[0088] In this application, the conjugated organic framework (COF) thin film was prepared by selecting monomer A and monomer B as raw materials as shown in Table 1 and Table 2, respectively, and preparing them in situ in Nafion membrane solution by hydrothermal method.
[0089] Table 1
[0090]
[0091] Table 2
[0092]
[0093] Example 1
[0094] The preparation method of COF-1 membrane precursor casting solution is as follows:
[0095] Weigh 25.0 mg (0.1 mmol) of 3,7-diamino-dibenzothiophene sulfone into a 20 ml glass bottle, add 2.5 ml of N,N-dimethylformamide (DMF), and sonicate until the powder particles are completely dissolved and the solution is a clear yellow-green solution. Then add 1 ml of membrane solution and stir vigorously to mix evenly. During stirring, slowly add 3.5 ml of a DMF solution of 2,4,6-tricarboxymethyl phloroglucinol (containing 14.0 mg (0.66 mmol) of 2,4,6-tricarboxymethyl phloroglucinol that has been sonicated evenly. Tighten the cap and place the solution in an 80°C constant temperature water bath and stir and heat for 12 hours to obtain the COF-1 membrane precursor casting solution.
[0096] Example 2
[0097] The preparation method of COF-1 membrane precursor casting solution is as follows:
[0098] Weigh 25.0 mg (0.1 mmol) of 3,7-diamino-dibenzothiophene sulfone into a 20 ml glass bottle, add 2.5 ml of N,N-dimethylformamide (DMF), and sonicate until the powder particles are completely dissolved and the solution is a clear yellow-green solution. Then add 0.5 ml of membrane solution and stir vigorously to mix evenly. During stirring, slowly add 3.5 ml of the sonicated DMF solution of 2,4,6-tricarboxymethyl phloroglucinol (containing 14.0 mg (0.66 mmol) of 2,4,6-tricarboxymethyl phloroglucinol), tighten the cap, and place in an 80°C constant temperature water bath and stir for 12 hours to obtain the COF-1 membrane precursor casting solution.
[0099] Example 3
[0100] The preparation method of COF-1 membrane precursor casting solution is as follows:
[0101] Weigh 25.0 mg (0.1 mmol) of 3,7-diamino-dibenzothiophene sulfone and 14.0 mg (0.66 mmol) of 2,4,6-tricarboxymethyl phloroglucinol into 20 ml glass bottles respectively. Add 2.5 ml and 3.5 ml of N,N-dimethylformamide (DMF) respectively. Sonicate until the powder particles are completely dissolved and the solution is a clear yellow-green solution. Mix the two solutions, then add 1 ml of membrane solution and stir vigorously until well mixed. Tighten the cap and place in an 80°C constant temperature water bath for 12 hours to prepare the COF-1 membrane precursor casting solution.
[0102] Example 4
[0103] The preparation method of COF-1 membrane precursor casting solution is as follows:
[0104] Weigh 25.0 mg (0.1 mmol) of 3,7-diamino-dibenzothiophene sulfone into a 20 ml glass bottle, add 2.5 ml of N,N-dimethylformamide (DMF), and sonicate until the powder particles are completely dissolved and the solution is a clear yellow-green solution. Then add 1 ml of membrane solution and stir vigorously to mix evenly. During stirring, slowly add 3.5 ml of a DMF solution of 2,4,6-tricarboxymethyl phloroglucinol (containing 14 mg (0.66 mmol) of 2,4,6-tricarboxymethyl phloroglucinol) that has been sonicated evenly. Tighten the cap and place the solution in an 80°C constant temperature water bath and stir and heat for 72 hours to obtain the COF-1 membrane precursor casting solution.
[0105] Example 5
[0106] The preparation method of COF-2 membrane precursor casting solution is as follows:
[0107] Weigh 25.0 mg (0.1 mmol) of 3,7-diamino-dibenzothiophene sulfone into a 20 ml glass bottle, add 2.5 ml of N,N-dimethylformamide (DMF), and sonicate until the powder particles are completely dissolved and the solution is a clear yellow-green solution. Then add 1 ml of membrane solution and stir vigorously to mix evenly. During stirring, slowly add 3.5 ml of sonicated DMF solution of 3,4,9,10-perylenetetracarboxylic anhydride (containing 39.2 mg (0.1 mmol)), tighten the cap, and place in a 100°C constant temperature water bath for 72 hours to prepare the COF-2 membrane precursor casting solution.
[0108] Example 6
[0109] The preparation method of COF-3 membrane precursor casting solution is as follows:
[0110] Weigh 21.0 mg (0.1 mmol) of 2,7-diamino-9H-fluorene-9-one and place it in a 20 ml glass bottle. Add 2.5 ml of N,N-dimethylformamide (DMF) and sonicate until the powder particles are completely dissolved, resulting in a clear yellow-green solution. Then add 1 ml of membrane solution and mix vigorously until homogeneous. While stirring, slowly add 3.5 ml of a DMF solution of 2,4,6-tricarboxymethyl phloroglucinol (containing 14.0 mg (0.66 mmol) of 2,4,6-tricarboxymethyl phloroglucinol that has been sonicated to homogeneity. Tighten the cap and heat in an 80°C water bath for 72 hours to obtain the COF-3 membrane precursor casting solution.
[0111] Example 7
[0112] The preparation method and washing process of COF membrane are as follows:
[0113] 0.5 ml of each of the COF membrane precursor casting solutions from Examples 1 to 6 were coated onto ordinary hydrophilic glass plates measuring 2 cm × 10 cm. The films were rapidly formed under heating at 120 °C and baking with an infrared lamp. After washing with N,N-dimethylformamide and acetone, and drying at 80 °C, the films were immersed in 0.5 M sulfuric acid solution at 80 °C for 1 hour, then transferred to water for 1 hour, and finally washed with deionized water to separate the COF membranes from the ordinary hydrophilic glass plates.
[0114] Example 8
[0115] The preparation method and washing process of COF membrane are as follows:
[0116] 10 ml of COF membrane precursor casting solution was drop-coated onto a 20 cm × 10 cm PET film plate. The film was heated in a forced-air oven at 120 °C for 2 h, then heated to 135 °C for 6 h. The film was washed with N,N-dimethylformamide and acetone, dried at 80 °C, and then soaked in 0.5 M sulfuric acid solution at 80 °C for 1 h. The film was then transferred to water and soaked for 1 h. Finally, the film was washed with deionized water and the COF membrane was separated from the PET film plate.
[0117] The COF membrane precursor casting solutions were selected from Examples 1 and 4, respectively, and the membranes prepared were labeled as "Example 1, 8" and "Example 4, 8", respectively.
[0118] The schematic diagram of the material structure of the membrane precursor casting solution prepared in Example 1 after film formation is shown below. Figure 1 As shown, the X-ray powder diffraction pattern is as follows: Figure 2 As shown, it exhibits small-angle diffraction peaks, confirming its characteristic as an organic covalent material; the scanning electron microscope image is shown below. Figure 3 As shown, the prepared membrane has a uniform surface and a thickness of 3.1 μm; the actual image is shown below. Figure 4 As shown, the membrane is transparent and self-supporting.
[0119] Example 9
[0120] The preparation method and washing process of COF membrane are as follows:
[0121] 10 ml of COF membrane precursor casting solution was drop-coated onto a 20 cm × 10 cm PET membrane plate. The membrane was heated in a forced-air oven at 120 °C for 2 h, then heated to 135 °C for 6 h. After washing with N,N-dimethylformamide and acetone, the membrane was dried at 80 °C and then transferred to water for 1 h. Finally, the COF membrane was separated from the PET membrane plate after washing with deionized water.
[0122] The COF membrane precursor casting solution was selected from Example 1 and Example 4, respectively, and the membranes prepared were labeled as "Example 1, 9", "Example 4, 9" and "Example 5, 9".
[0123] Example 10
[0124] The preparation method and washing process of COF membrane are as follows:
[0125] 5 ml of each of the COF-1 membrane precursor casting solutions from Examples 1 to 6 were drop-coated onto 20 cm × 10 cm PET membrane plates. The membranes were heated in a forced-air oven at 120 °C for 2 h, then heated to 135 °C for 6 h. After washing with N,N-dimethylformamide and acetone, the membranes were dried at 80 °C and then transferred to water for 1 h. Finally, the COF membranes were separated from the PET membrane plates using deionized water.
[0126] Example 11
[0127] The COF membrane photocatalytic system is constructed as follows:
[0128] The COF membrane was sandwiched in an H-shaped double-cylinder reaction tank. In the right reaction tank, 0.1M ascorbic acid aqueous solution and an appropriate amount of chloroplatinic acid aqueous solution (3.75 mg Pt / ml) were added. After 1 hour of illumination, Pt was deposited, and the membrane was thoroughly washed with plenty of water. In the left reaction tank, an appropriate amount of cobalt nitrate solution (1 mg Co / ml) was added. After 1 hour of illumination, Co3O4 was deposited, and the membrane was thoroughly washed with plenty of water. Then, 50 ml of deionized water was added to each tank, and the membrane was irradiated under sunlight for one day using a 300W xenon lamp with an AM 1.5G filter.
[0129] The COF membranes were selected from Examples 1 and 8, 4 and 8, 1 and 9, 4 and 9, respectively, and the results are shown in the appendix. Figure 5 As shown, the COF membranes prepared in Examples 4 and 8 exhibit the best performance.
[0130] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.
Claims
1. A proton-conducting organic porous membrane catalyst, characterized by, The proton-conducting organic porous membrane catalyst is sandwiched in the middle of the H-shaped double-cylinder reaction tank, so that hydrogen and oxygen self-separation occurs on both sides of the proton-conducting organic porous membrane catalyst. The proton-conducting organic porous membrane catalyst includes an organic porous thin film material; The organic porous thin film material includes a catalyst component and a Nafion membrane; The catalyst component is a covalent organic framework; The organic porous thin film material includes an electron donor and an electron acceptor; The organic porous thin film material is prepared by the following steps: S1. Obtain solutions containing electron donors and electron acceptors respectively; add Nafion membrane solution to the solution containing electron donors, and then slowly add the solution containing electron acceptors to mix and synthesize the precursor casting solution. The electron donor monomer and the electron acceptor monomer react in situ in Nafion membrane solution under the catalysis of sulfonic acid groups; S2. The precursor casting solution is coated on the substrate and heated to form a film. After heating to form a film, one side of the organic porous film material is contacted with an aqueous solution containing an oxygen evolution cocatalyst metal precursor and an oxygen evolution cocatalyst is photodeposited in situ. The other side is contacted with an aqueous solution containing a hydrogen evolution cocatalyst metal precursor and a hydrogen evolution cocatalyst is photodeposited in situ to form a proton-conducting organic porous film catalyst. The catalyst component is generated in situ in the Nafion membrane and encapsulated by the sulfonated polymer in the Nafion membrane. The aqueous solution containing the oxygen evolution cocatalyst metal precursor is an aqueous solution of raw material A, wherein raw material A is selected from at least one of CoCl2, Co(NO3)2, MnCl2, and RuCl2; The aqueous solution containing the hydrogen evolution co-catalyst metal precursor is an aqueous solution of raw material B, wherein raw material B is selected from at least one of H2PtCl4, K2PtCl4, K2RhCl4, K2AuCl4, and AgNO3; One side of the organic porous thin film material is deposited with an oxygen evolution cocatalyst, and the other side is deposited with a hydrogen evolution cocatalyst.
2. The proton-conducting organic porous membrane catalyst of claim 1, wherein, The electron donor is monomer A, and the electron acceptor is monomer B; The monomer A is selected from at least one of the following structural formulas. ； The monomer B is selected from at least one of the following structural formulas. ； R is selected from at least one of CH3, OCH3, F, Cl, and Br.
3. The proton-conducting organic porous membrane catalyst of claim 1, wherein, The oxygen evolution cocatalyst is at least one selected from IrO2, RuO2, NiO, Mn3O4, and Co3O4; The hydrogen evolution cocatalyst is at least one of Pt, Rh, and Ag; The proton-conducting organic porous membrane catalyst contains at least one of sulfonic acid group, carboxyl group, hydroxyl group, metal-free porphyrin, and imine.
4. A process for the preparation of the proton-conducting organic porous membrane catalyst of claim 1 or 2, characterized in that, Includes the following steps: S1. Obtain solutions containing electron donors and electron acceptors respectively; add Nafion membrane solution to the solution containing electron donors, and then slowly add the solution containing electron acceptors to mix and synthesize the precursor casting solution. The electron donor monomer and the electron acceptor monomer react in situ in Nafion membrane solution under the catalysis of sulfonic acid groups; S2. The precursor casting solution obtained in step S1 is coated on the substrate and heated to form a film. After heating to form a film, one side of the organic porous film material is contacted with an aqueous solution containing the oxygen evolution cocatalyst metal precursor and the oxygen evolution cocatalyst is photodeposited in situ. The other side is contacted with an aqueous solution containing the hydrogen evolution cocatalyst metal precursor and the hydrogen evolution cocatalyst is photodeposited in situ to form a proton-conducting organic porous film catalyst. The aqueous solution containing the oxygen evolution cocatalyst metal precursor is an aqueous solution of raw material A, wherein raw material A is selected from at least one of CoCl2, Co(NO3)2, MnCl2, and RuCl2; The aqueous solution containing the hydrogen evolution cocatalyst metal precursor is an aqueous solution of raw material B, wherein raw material B is selected from at least one of H2PtCl4, K2PtCl4, K2RhCl4, K2AuCl4, and AgNO3.
5. The preparation method according to claim 4, characterized in that, The molar ratio of the electron donor to the electron acceptor is 1:0.6~2; The total weight ratio of the electron donor and electron acceptor to the weight of the Nafion membrane solution is 1:1 to 10. In step S1, the synthesis conditions include: a reaction temperature of 60~180℃ and a reaction time of 12~72h. In step S2, the conditions for heating to form a film include: heating at 60~100℃ with forced air for 2~6 hours, and then heating to 120~150℃ for 3~12 hours. In step S2, the substrate is made of at least one of hydrophilic glass, polyethylene terephthalate, polyphenylene ether sulfone, polymethyl methacrylate, and polyetherimide.
6. The preparation method according to claim 4, characterized in that, The solvents in the solutions containing electron donors and electron acceptors are independently selected from at least one organic solvent selected from o-dichlorobenzene, methanol, ethanol, N,N-dimethylformamide, N-methylpyrrolidone, dimethyl sulfoxide, dioxane, and tetrahydrofuran.
7. Use of the proton-conducting organic porous membrane catalyst according to any one of claims 1 to 3, of the proton-conducting organic porous membrane catalyst prepared according to the method of any one of claims 4 to 6 for the conversion of solar energy into chemical energy, characterized in that, The proton-conducting organic porous membrane catalyst is sandwiched in the middle of an H-shaped double-cylinder reaction tank, so that hydrogen and oxygen self-separation occurs on both sides of the proton-conducting organic porous membrane catalyst.