A bridged electron donor-acceptor polymer, its preparation method and applications

Abstract

The present invention discloses a bridged electron donor-acceptor polymer, a preparation method thereof and an application thereof. In the polymer, an alkynyl group is used as an electron bridge to connect an electron donor unit and an electron acceptor unit. The electron donor unit is tetraphenylethylene, 2,4,6-triphenyltriazine or benzocarbazole, and the electron acceptor unit is anthraquinone or sulfoxide. By introducing an alkynyl group as an electron bridge between specific electron donors and electron acceptors, the present invention reduces the recombination of photo-generated carriers. The obtained bridged electron donor-acceptor polymer can be used for photocatalytic production of hydrogen peroxide and photocatalytic degradation of organic pollutants.

Description

Technical Field

[0001] The present invention relates to the field of photocatalysis technology, and more specifically, to a bridged electron donor-acceptor polymer, a preparation method thereof, and an application thereof. Background Art

[0002] Hydrogen peroxide is widely used in fields such as chemical synthesis, environmental protection, papermaking, national defense and military, electronics, medicine, food, and agriculture. It is an important industrial raw material and can be used as an oxidant, bleaching agent, disinfectant, polymerization initiator, crosslinking agent, and propellant. The existing photocatalysts for synthesizing hydrogen peroxide are mainly modified graphitic carbon nitride. However, the water oxidation ability of the modified graphitic carbon nitride material is poor. When used for producing hydrogen peroxide, organic solvents often need to be added as electron donors to improve the yield. At the same time, the adsorption of oxygen by the carbon nitride material is poor, and pure oxygen needs to be continuously introduced to increase the contact between oxygen and the catalyst surface and improve the probability of being reduced.

[0003] To solve the above problems, Chinese Patent CN113145167A discloses an electron donor-acceptor polymer. This polymer uses tetraphenylethylene or 2,4,6-triphenyltriazine as the electron donor unit and any one of anthraquinone, anthracene, or biphenyl as the electron acceptor unit. Using this polymer as a photocatalyst for synthesizing hydrogen peroxide solves the problem that pure oxygen needs to be continuously introduced and organic solvents need to be added as electron donors when carbon nitride materials are used for producing hydrogen peroxide. However, there is still a problem of too fast recombination of photo-generated carriers. Summary of the Invention

[0004] The primary object of the present invention is to overcome the problem of too fast recombination of photo-generated carriers when the above existing polymer is used as a photocatalyst for synthesizing hydrogen peroxide, and to provide a bridged electron donor-acceptor polymer.

[0005] A further object of the present invention is to provide a preparation method of the bridged electron donor-acceptor polymer.

[0006] Another object of the present invention is to provide an application of the above bridged electron donor-acceptor polymer.

[0007] The above objects of the present invention are achieved by the following technical solutions:

[0008] A bridged electron donor-acceptor polymer has the following chemical structural formula:

[0009]

[0010] wherein the degree of polymerization n = 1 to 100, is the electron donor unit; is the electron acceptor unit; is the electron bridge;

[0011] The electron donor unit is selected from any one of the formulas (a-1) to (a-3):

[0012]

[0013] The electron acceptor unit is selected from any one of the formulas (b-1) to (b-2):

[0014]

[0015] The electron bridge is

[0016] P represents the site connected to the electron acceptor unit, m represents the site connected to the electron donor unit, and J and K represent the sites connected to the electron bridge.

[0017] In the polymer of the present invention, an alkynyl group is used as an electron bridge to connect the electron donor unit and the electron acceptor unit. The electron donor unit is tetraphenylethylene, 2,4,6-triphenyltriazine or benzocarbazole, and the electron acceptor unit is anthraquinone or sulfoxide. By introducing an alkynyl group as an electron bridge between specific electron donors and electron acceptors, the intramolecular electron transfer of photo-generated carriers is promoted, the recombination of photo-generated carriers can be inhibited, and thus the yield of the obtained polymer for photocatalytic production of hydrogen peroxide can be improved.

[0018] Preferably, the chemical formula structural formula of the bridged electron donor-acceptor polymer is as follows:

[0019]

[0020] Preferably, the chemical structural formula of the bridged electron donor-acceptor polymer is any one of the formulas (I-1) to (I-4):

[0021]

[0022]

[0023]

[0024] The present invention also provides a preparation method of a bridged electron donor-acceptor polymer, comprising the following steps:

[0025] S1. Under an inert atmosphere, 2,6-dibromoanthraquinone and 4-ethynylbenzonitrile are refluxed and reacted for 10 to 24 hours at 60 to 100 °C through a Sonogashira reaction, and aftertreatment is carried out to obtain a bridged electron donor-acceptor polymer precursor;

[0026] S2. Under an inert atmosphere, mix the bridged electron donor-acceptor polymer precursor, organic solvent A, and trifluoromethanesulfonic acid, react at -15 to 10 °C for 1 to 2 h, then raise the temperature to 20 to 30 °C and react for 1 to 2 h, and then react at 80 to 110 °C for 10 to 24 h. Quench the reaction with cold water, wash, and perform post-treatment to obtain the bridged electron donor-acceptor polymer.

[0027] Preferably, the organic solvent A is chloroform and / or dichloromethane.

[0028] The present invention also provides another method for preparing a bridged electron donor-acceptor polymer, comprising the following steps:

[0029] Under an inert atmosphere, mix an alkynyl monomer having an electron donor unit structure, a dibromo monomer having an electron acceptor unit structure, a base, a palladium catalyst, copper iodide, and an organic solvent B, raise the temperature to carry out the Sonogashira coupling reaction, wash, extract, and perform post-treatment to obtain the bridged electron donor-acceptor polymer.

[0030] The post-treatment in the present invention sequentially includes drying, grinding, ultrasonic dispersion, suction filtration, and secondary drying.

[0031] The inert atmosphere in the present invention is a nitrogen atmosphere and / or an argon atmosphere.

[0032] Preferably, the temperature of the Sonogashira coupling reaction is 70 °C to 90 °C, and the time is 24 to 48 h.

[0033] Preferably, the molar ratio of the alkynyl monomer to the dibromo monomer is 1:(1 to 4).

[0034] Preferably, the base is one or more of triethylamine, sodium carbonate, and potassium carbonate.

[0035] Preferably, the palladium catalyst is tetrakis(triphenylphosphine)palladium and / or bis(triphenylphosphine)palladium chloride.

[0036] Preferably, the organic solvent B is one or more of dimethylacetamide, N-methylpyrrolidone, and dimethylformamide.

[0037] The present invention also provides the application of the bridged electron donor-acceptor polymer in photocatalysis.

[0038] Preferably, the photocatalysis is photocatalytic production of hydrogen peroxide and photocatalytic degradation of organic pollutants.

[0039] More preferably, the organic pollutants include but are not limited to phenol, bisphenol A, and dyes.

[0040] The method for preparing hydrogen peroxide using the bridged electron donor-acceptor polymer as a photocatalyst in the present invention comprises the following steps:

[0041] 1 mg of the bridged electron acceptor polymer was added to 50 mL of pure water, ultrasonically dispersed for 0.5 h, stirred, and irradiated with xenon lamp light, with the light intensity controlled at 100 mW / cm 2 .

[0042] In the present invention, after the electron bridge and the electron acceptor obtain electrons, they can serve as active sites for oxygen reduction, and selectively reduce oxygen to hydrogen peroxide. The electron bridge can change the path of water oxidation and directly oxidize water to produce hydrogen peroxide.

[0043] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0044] The present invention provides a bridged electron donor-acceptor polymer. The bridged electron donor-acceptor polymer uses an alkynyl group as an electron bridge to connect an electron donor unit and an electron acceptor unit. The electron donor unit is tetraphenylethylene, 2,4,6-triphenyltriazine, or benzocarbazole, and the electron acceptor unit is anthraquinone or sulfoxide. By introducing an alkynyl group as an electron bridge, the recombination of photo-generated carriers is reduced, so that the bridged electron donor-acceptor polymer can be used for photocatalytic production of hydrogen peroxide and photocatalytic degradation of organic pollutants. When the bridged electron donor-acceptor polymer of the present invention is used as a photocatalyst for preparing hydrogen peroxide, the hydrogen peroxide production rate is higher than 2000 μmol / h / g. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 It is a comparative diagram of the steady-state fluorescence of the polymers obtained in Example 1 and Comparative Examples 2-3 of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0046] In order to more clearly and completely describe the technical solutions of the present invention, the present invention will be further described in detail below through specific examples. It should be understood that the specific examples described herein are only used to explain the present invention and are not used to limit the present invention, and various changes can be made within the scope defined by the claims of the present invention.

[0047] 3,6-Diethynyl-9-(4-ethynylphenyl)-9H-carbazole, abbreviated as tri-alkynyl NPC, was purchased from Shanghai Tengqian Biotechnology Co., Ltd., and the product number was TQ0442.

[0048] 4-[6-(4-cyanophenyl)-9,10-dioxo-9,10-dihydroanthracen-2-yl]benzonitrile was purchased from Jilin Zhongke Yanshen Technology Co., Ltd., and the product number is YSZC829.

[0049] 4-[2-(4-cyanophenyl)ethynyl]benzonitrile was synthesized according to the reference (Adv. Mater. 2019, 1904433).

[0050] Example 1

[0051] A bridged electron donor-acceptor polymer has the following chemical structural formula:

[0052]

[0053] The preparation method of the bridged electron donor-acceptor polymer includes the following steps:

[0054] S1. Dissolve 35 mg (0.05 mmol) of tetrakis(triphenylphosphine)palladium, 9.5 mg (0.05 mmol) of copper(I) iodide, 366 mg (1 mmol) of 2,6-dibromoanthraquinone and 381 mg (3 mmol) of 4-ethynylbenzonitrile in tetrahydrofuran. After bubbling with argon at room temperature for 30 minutes, slowly add 8 ml of triethylamine and 6 ml of diisopropylamine. Subsequently, stir and react at 85 °C for 16 h under an argon atmosphere. After the reaction is completed, wash the product with tetrahydrofuran, ammonia water, toluene and acetonitrile and dry it under vacuum to obtain an intermediate.

[0055] S2. Weigh 200 mg (0.44 mmol) of the intermediate, add 20 ml of chloroform, and ultrasonically disperse it for 30 min. At 0 °C, under an Ar / N2 atmosphere, add 3 ml of trifluoromethanesulfonic acid to the reaction flask. Slowly add the solution of the dispersed sample to the reaction flask in batches. After the addition is completed, continue to stir and react for 2 h, transfer to room temperature and stir for 1 h, and then react at 100 °C overnight. After the reaction is completed, quench the reaction with cold water, wash the product with a large amount of dilute ammonia water and water until the pH is 7, dry it in an oven at 80 °C for 24 h, grind the dried product into powder, disperse it in 200 ml of water, ultrasonically disperse it for 36 h, filter by suction, and dry to obtain the final product, denoted as triphenyltriazine-alkynyl-anthraquinone (TPT-alkynyl-AQ). After analysis, the degree of polymerization of the polymer is distributed in the range of 1 - 100.

[0056] Example 2

[0057] A bridged electron donor-acceptor polymer, the chemical structural formula of which is as follows:

[0058]

[0059] The preparation method of the bridged electron donor-acceptor polymer comprises the following steps:

[0060] Add 76 mg (0.2 mmol) of 2,4,6-tris(4-ethynylphenyl)-1,3,5-triazine, 112 mg (0.3 mmol) of 3,7-dibromobenzo[b]thiophene 5,5-dioxide, 7 mg (0.01 mmol) of bis(triphenylphosphine)palladium dichloride, and 1.9 mg (0.01 mmol) of copper(I) iodide into a reaction flask. Add N,N-dimethylformamide and triethylamine to the reaction flask in a volume ratio of 1:1 (10 ml:10 ml), degas with Ar / N2 for 30 min, and then react at 80 °C for 48 h under Ar / N2. After the reaction is completed, wash the product with N,N-dimethylformamide, and perform Soxhlet extraction with methanol and dichloromethane for 48 h. Dry in an oven at 80 °C for 24 h. Grind the dried product into powder, disperse it in 200 ml of water, perform ultrasonic dispersion for 36 h, filter by suction, and dry to obtain the final product, denoted as triphenyltriazine-alkynyl-dibenzothiophene sulfone (TPT-alkynyl-DBTSO). After analysis, the degree of polymerization distribution of the polymer is in the range of 1-100.

[0061] Example 3

[0062] A bridged electron donor-acceptor polymer, the chemical structural formula of which is as follows:

[0063]

[0064] The preparation method of the bridged electron donor-acceptor polymer comprises the following steps:

[0065] Accurately weigh 27 mg (0.02 mmol) of tetrakis(triphenylphosphine)palladium, 5 mg (0.03 mmol) of copper(I) iodide, 549 mg (1.5 mmol) of 2,6-dibromoanthraquinone and 321.4 mg (0.75 mmol) of tetrakis(4-ethynylphenyl)ethylene. Dissolve the above drugs in 60 ml of N,N-dimethylformamide, bubble with argon at room temperature for 30 minutes, then slowly add 60 ml of triethylamine, and then stir and react at 80 °C for 48 h under an argon atmosphere. After the reaction is completed, ultrasonically treat the product in N,N-dimethylformamide, then wash with ethanol and water and dry in vacuo to obtain the polymer, denoted as tetraphenylethylene-alkynyl-anthraquinone (TPE-alkynyl-AQ). After analysis, the degree of polymerization distribution of the polymer is in the range of 1-100.

[0066] Example 4

[0067] A bridged electron donor-acceptor polymer has the following chemical structural formula:

[0068]

[0069] The preparation method of the bridged electron donor-acceptor polymer includes the following steps:

[0070] Accurately weigh 27 mg (0.02 mmol) of tetrakis(triphenylphosphine)palladium, 5 mg (0.03 mmol) of copper(I) iodide, 534 mg (1.5 mmol) of 2,6-dibromosulfoxide, and 321.4 mg (0.75 mmol) of tetrakis(4-ethynylphenyl)ethylene. Dissolve the above drugs in 60 ml of N,N-dimethylformamide. After bubbling with argon at room temperature for 30 minutes, slowly add 60 ml of triethylamine. Subsequently, stir and react at 80 °C for 48 h under an argon atmosphere. After the reaction is completed, ultrasonically treat the product in N,N-dimethylformamide, then wash with ethanol and water and dry under vacuum to obtain the polymer, denoted as tetraphenylethylene-alkynyl-dibenzothiophene sulfone (TPE-alkynyl-DBTSO). After analysis, the degree of polymerization of the polymer is distributed in the range of 1 to 100.

[0071] Example 5

[0072] A bridged electron donor-acceptor polymer has the following chemical structural formula:

[0073]

[0074] The preparation method of the bridged electron donor-acceptor polymer includes the following steps:

[0075] Accurately weigh 27 mg (0.02 mmol) of tetrakis(triphenylphosphine)palladium, 5 mg (0.03 mmol) of copper(I) iodide, 534 mg (1.5 mmol) of 2,6-dibromoanthraquinone, and 315 mg (1 mmol) of 3,6-diethynyl-9-(4-ethynylphenyl)-9H-carbazole. Dissolve the above drugs in 60 ml of N,N-dimethylformamide. After bubbling with argon at room temperature for 30 minutes, slowly add 60 ml of triethylamine. Subsequently, stir and react at 80 °C for 48 h under an argon atmosphere. After the reaction is completed, ultrasonically treat the product in N,N-dimethylformamide, then wash with ethanol and water and dry under vacuum to obtain the polymer, denoted as carbazole-alkynyl-anthraquinone (Cz-alkynyl-AQ). After analysis, the degree of polymerization of the polymer is distributed in the range of 1 to 100.

[0076] Comparative Example 1

[0077] An electron donor-acceptor polymer has the following chemical structural formula:

[0078]

[0079] The preparation method of the electron donor-acceptor polymer includes the following steps:

[0080] Tetrakis(4-boronic acid phenyl)ethylene (254 mg, 0.5 mmol) and 2,6-dibromoanthraquinone (182 mg, 0.5 mmol) were fully mixed in a molar ratio of 1:1, potassium carbonate (1.0 g) and tetrakis(triphenylphosphine)palladium (5 mg) were added, using dimethylformamide (30 ml) and water (4 ml) as solvents, under an argon atmosphere, the temperature was raised to 150 °C, held for 48 h, and after natural cooling, the product was obtained, denoted as tetraphenylethylene-anthraquinone (TPE-AQ).

[0081] Comparative Example 2

[0082] An electron donor-acceptor polymer has the following chemical structural formula:

[0083]

[0084] The preparation method of the electron donor-acceptor polymer includes the following steps:

[0085] Weigh 200 mg (0.49 mmol) of 4-[6-(4-cyanophenyl)-9,10-dioxo-9,10-dihydroanthracen-2-yl]benzonitrile, add 20 ml of chloroform, ultrasonically disperse for 30 min, at 0 °C, under an Ar / N2 atmosphere, add 3 ml of trifluoromethanesulfonic acid to the reaction flask, slowly add the solution of the dispersed sample to the reaction flask in batches, continue stirring the reaction for 2 h after addition, transfer to room temperature and stir for 1 h, then react at 100 °C overnight, after the reaction is completed, quench the reaction with cold water, wash the product with a large amount of dilute ammonia water and water until the pH is 7, dry in an oven at 80 °C for 24 h, grind the dried product into powder, disperse it in 200 ml of water, ultrasonically disperse for 36 h, filter by suction, and dry to obtain the final product, denoted as triphenyltriazine-anthraquinone (TPT-AQ).

[0086] Comparative Example 3

[0087] A bridged electron donor-acceptor polymer has the following chemical structural formula:

[0088]

[0089] The preparation method of the bridged electron donor-acceptor polymer comprises the following steps:

[0090] Add 175 mg (0.75 mmol) of 2,6-diaminoanthraquinone, 197 mg (0.5 mmol) of 2,4,6-tris(4-formylphenyl)-1,3,5-triazine, 4 ml of N,N-dimethylformamide, and 2 ml of 1,4-dioxane (the volume ratio of N,N-dimethylformamide to 1,4-dioxane is 2:1) into a 10-ml reaction flask, ultrasonically disperse for 1 h, then add 1 ml of acetic acid with a concentration of 6 mol / L, quickly freeze with liquid nitrogen, evacuate and fill with N2 / Ar gas, repeat the operation three times and then let it naturally return to room temperature, and then react in an oven at 160 °C for 72 h. After the reaction is completed, wash the product repeatedly with N,N-dimethylformamide, dichloromethane, and ethanol, dry in an oven at 80 °C for 24 h, grind the dried product into powder, disperse it in 200 ml of water, ultrasonically disperse for 36 h, filter by suction, and dry to obtain the final product, denoted as triphenyltriazine-imine-anthraquinone (TPT-imine-AQ).

[0091] Comparative Example 4

[0092] A polymer, whose chemical structural formula is as follows:

[0093]

[0094] The preparation method of the polymer comprises the following steps:

[0095] Weigh 200 mg (0.88 mmol) of 4-[2-(4-cyanophenyl)ethynyl]benzonitrile, add 20 ml of chloroform, ultrasonically disperse for 30 min, under the atmosphere of Ar / N2 at 0 °C, add 3 ml of trifluoromethanesulfonic acid to the reaction flask, slowly add the solution of the dispersed sample to the reaction flask in batches, continue to stir and react for 2 h after the addition, transfer to room temperature and stir for 1 h, then react overnight at 100 °C. After the reaction is completed, quench the reaction with cold water, wash the product with a large amount of dilute ammonia water and water until the pH is 7, dry in an oven at 80 °C for 24 h, grind the dried product into powder, disperse it in 200 ml of water, ultrasonically disperse for 36 h, filter by suction, and dry to obtain the final product, denoted as triphenyltriazine-alkynyl-triphenyltriazine (TPT-alkynyl-TPT).

[0096] Testing and characterization

[0097] Disperse the polymers described in Examples 1 to 5 and Comparative Examples 1 to 4 in pure water by ultrasonic dispersion respectively, simulate sunlight irradiation with a xenon lamp, and the light power is 100 mW / cm 2, photocatalytic hydrogen peroxide production tests were carried out, and the hydrogen peroxide production rates are shown in Table 1.

[0098] Table 1 Hydrogen peroxide production rate (μmol / h / g)

[0099]

[0100] As shown in Table 1, the bridged electron donor-acceptor polymers described in Examples 1-5 of the present invention have a high hydrogen peroxide production rate under the conditions of not requiring continuous oxygen supply and organic solvents as electron donors, while the electron donor-acceptor polymers without alkynes described in Comparative Examples 1-2 have a low hydrogen peroxide production rate under the same conditions. The bridged electron donor-acceptor polymer described in Comparative Example 3 uses an imine bond as an electron bridge and has an even lower hydrogen peroxide production rate. Comparative Example 4 is a polymer without an electron acceptor, and its hydrogen peroxide production rate is only one-sixth of that of the polymer with an electron acceptor. It shows that the polymer obtained by connecting the electron donor and electron acceptor of the present invention with an alkynyl group as an electron bridge has a high hydrogen peroxide production rate when used for photocatalytic hydrogen peroxide production.

[0101] The steady-state fluorescence tests were carried out on the polymers obtained in Example 1 and Comparative Examples 2-3 using a FLS1000 Edinburgh steady-state / transient fluorescence spectrometer. The solid powders of the three polymers were tested with an excitation wavelength of 395 nm, and the emission spectrum range was 415 - 800 nm. The test slit sizes of the three materials were kept consistent.

[0102] Figure 1 This is the comparative diagram of the steady-state fluorescence of the polymers obtained in Example 1 of the present invention and Comparative Examples 2-3. The lower the peak intensity of the steady-state fluorescence diagram, the less the recombination of photo-generated carriers. It can be seen from the above figure that when using an alkyne as an electron bridge (TPT-alkynyl-AQ), compared with TPT-AQ without an electron bridge or (TPT-imine-AQ) using an imine bond as an electron bridge, the recombination of photo-generated carriers can be significantly reduced.

[0103] Obviously, the above-mentioned embodiments of the present invention are merely examples for clearly illustrating the present invention, rather than limitations on the implementation manners of the present invention. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to enumerate all the implementation manners here. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

1. A bridged electron donor-acceptor polymer, characterized in that, It has the following chemical structural formula: Among them, the degree of polymerization n = 1 to 100, is an electron donor unit; is an electron acceptor unit; is an electron bridge; The electron donor unit is selected from any one of formulas (a-1) to (a-3): The electron acceptor unit is selected from any one of formulas (b-1) to (b-2): The electronic bridge is P represents the site connected to the electron acceptor unit, m represents the site connected to the electron donor unit, and J and K represent the sites connected to the electron bridge; The bridged electron donor-acceptor polymer does not contain the following structural formula:

2. The bridged electron donor-acceptor polymer according to claim 1, characterized in that, The chemical structural formula is as follows:

3. The bridged electron donor-acceptor polymer according to claim 1, characterized in that, The chemical structural formula is any one of formulas (I-2) to (I-4):

4. The preparation method of the bridged electron donor-acceptor polymer according to claim 2, characterized in that, It includes the following steps: S1. Under an inert atmosphere, 2,6-dibromoanthraquinone and 4-ethynylbenzonitrile are refluxed at 60-100 °C for 10-24 h through a Sonogashira coupling reaction, and after treatment, a bridged electron donor-acceptor polymer precursor is obtained; S2. Under an inert atmosphere, the bridged electron donor-acceptor polymer precursor, organic solvent A, and trifluoromethanesulfonic acid are mixed and reacted at -15-10 °C for 1-2 h, then heated to 20-30 °C and reacted for 1-2 h, and then reacted at 80-110 °C for 10-24 h. The reaction is quenched with cold water, washed, and post-treated to obtain the bridged electron donor-acceptor polymer; Among them, in step S2, the organic solvent A is chloroform and / or dichloromethane.

5. The preparation method of the bridged electron donor-acceptor polymer according to claim 3, characterized in that, It includes the following steps: Under an inert atmosphere, an alkynyl monomer with an electron donor unit structure, a dibromo monomer with an electron acceptor unit structure, a base, a palladium catalyst, copper iodide, and an organic solvent B are mixed, and the temperature is raised for a Sonogashira coupling reaction. After washing, extraction, and post-treatment, the obtained product is the bridged electron donor-acceptor polymer; Among them, the organic solvent B is one or more of dimethylacetamide, N-methylpyrrolidone, and dimethylformamide.

6. The preparation method of the bridged electron donor-acceptor polymer according to claim 5, characterized in that, The temperature of the Sonogashira coupling reaction is 70 °C to 90 °C, and the time is 24 to 48 h.

7. The preparation method of the bridged electron donor-acceptor polymer according to claim 5, characterized in that, The molar ratio of the alkynyl monomer to the dibromo monomer is 1:(1-4).

8. The preparation method of the bridged electron donor-acceptor polymer according to claim 5, characterized in that, The base is one or more of triethylamine, sodium carbonate, and potassium carbonate.

9. The preparation method of the bridged electron donor-acceptor polymer according to claim 5, characterized in that, The palladium catalyst is tetrakis(triphenylphosphine)palladium and / or bis(triphenylphosphine)palladium chloride.

10. Use of the bridged electron donor-acceptor polymer according to any one of claims 1 to 3 in photocatalysis; wherein, The bridged electron donor-acceptor polymer includes the bridged electron donor-acceptor polymer of formula (I-1) described in claim 1; The photocatalysis is photocatalytic production of hydrogen peroxide.

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