Electron donor-acceptor conjugated polymer as well as preparation method and application thereof

Abstract

The invention discloses an electron donor-acceptor conjugated polymer as well as a preparation method and application thereof. According to the polymer, carbazole with an oligo-ether chain or an alkyl chain is adopted as an electron donor unit, anthraquinone is adopted as an electron acceptor unit, alkynyl is adopted as an electron bridge, and connection of the electron donor unit and the electron acceptor unit is achieved. According to the electron donor-acceptor conjugated polymer, after an electron bridge and an electron acceptor obtain electrons under illumination, the electrons can serve as active sites for oxygen reduction, oxygen is reduced into hydrogen peroxide in a high-selectivity mode, the electron donor-acceptor conjugated polymer is an excellent photocatalyst, and the yield of hydrogen peroxide produced through photocatalysis can be increased.

Description

Technical Field

[0001] The present invention relates to the field of photocatalysis technology. More specifically, it relates to an electron donor-acceptor conjugated polymer, a preparation method and application thereof, and a strategy for improving the photocatalytic production rate of hydrogen peroxide based on this polymer. Background Art

[0002] As a chemical with a crucial position in modern industry and life, hydrogen peroxide plays an irreplaceable role in many fields such as medical disinfection, wastewater treatment, and energy storage. However, the traditional industrial production method of anthraquinone oxidation not only consumes a huge amount of energy but also produces toxic by-products during the production process, restricting its sustainable development. Photocatalytic synthesis of hydrogen peroxide uses water and oxygen, which are abundant and sustainable on the earth, as raw materials, in line with the concepts of green chemistry and sustainable development. Currently, in the research of photocatalytic synthesis of hydrogen peroxide, organic photocatalysts can flexibly adjust the photophysical and photochemical processes during the photocatalytic synthesis of hydrogen peroxide by designing and regulating the molecular structure, thereby optimizing the catalytic performance. However, problems such as low generation rate of photo-generated carriers, high exciton binding energy, and unsatisfactory hydrogen peroxide production rate limit the further development and practical application of organic photocatalysts. Therefore, developing organic photocatalysts with high photo-generated carrier generation and separation ability, low exciton binding energy, and high hydrogen peroxide production rate is the research focus and key challenge in this field currently.

[0003] Chinese Patent CN113145167A discloses an electron donor-acceptor polymer, a preparation method and application thereof. This polymer photocatalyst is prepared by Suzuki polymerization reaction with a boronic acid-based monomer having an electron donor unit structure and a dibromo monomer having an electron acceptor unit structure. When this electron donor-acceptor conjugated polymer is dispersed in pure water and irradiated with simulated sunlight with a light power of 100 mW / cm 2 for the experiment of photocatalytic production of hydrogen peroxide, the highest production rate of hydrogen peroxide is 1400 μmol·g -1 ·h -1 . Thus, it can be seen that there is still a large room for improvement in the production rate of the polymer in photocatalytic production of hydrogen peroxide. Summary of the Invention

[0004] The primary object of the present invention is to overcome the problem of low hydrogen peroxide production rate when the existing electron donor-acceptor conjugated polymer is used as a photocatalyst for synthesizing hydrogen peroxide, and to provide an electron donor-acceptor conjugated polymer to improve the production rate of photocatalytic production of hydrogen peroxide.

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

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

[0007] The above object of the present invention is achieved by the following technical solutions: An electron donor-acceptor conjugated polymer has a structure shown in the following formula (I): Formula (I); Wherein, is an electron donor unit; is an electron acceptor unit; is an electron bridge; the degree of polymerization n = 1 to 100; The electron donor unit is of formula (a-1) or (a-2); Formula (a-1); Formula (a-2); In formula (a-2), R is a straight-chain alkyl group with 12 to 14 carbon atoms; The electron acceptor unit is of formula (b): Formula (b); The electron bridge is ; The 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.

[0008] The present invention discloses a conjugated polymer with an alternating connection structure of electron donor - electron acceptor, where the electron donor and the electron acceptor are connected by an alkynyl electron bridge, the electron donor unit is a carbazole with an oligoether chain or an alkyl chain, and the electron acceptor unit is anthraquinone.

[0009] For the electron donor-acceptor conjugated polymer of the present invention, under light illumination, after the alkynyl and the electron acceptor anthraquinone obtain electrons, they can serve as active sites for oxygen reduction, and selectively reduce oxygen to hydrogen peroxide, which is an excellent photocatalyst and can improve the yield of photocatalytic production of hydrogen peroxide.

[0010] By introducing an oligoether chain at the carbazole group of the electron donor in the catalyst of the present invention, the electronic effect and steric effect of the oligoether chain effectively adjust the structure of the electron donor, promoting more exciton dissociation to form photogenerated carriers, and thus improving the yield of photocatalytic production of hydrogen peroxide when the obtained electron donor-acceptor conjugated polymer is used as a photocatalyst.

[0011] By introducing a straight-chain alkyl group with 12 to 14 carbon atoms at the carbazole group of the electron donor in the catalyst of the present invention, more exciton dissociation can be promoted to form photogenerated carriers, and thus the yield of photocatalytic production of hydrogen peroxide when the obtained electron donor-acceptor conjugated polymer is used as a photocatalyst is improved.

[0012] Preferably, the electron donor-acceptor conjugated polymer has the structure shown in the following formula (II): Formula (II).

[0013] Preferably, the electron donor-acceptor conjugated polymer has the structure shown in the following formula (III): Formula (III).

[0014] The present invention also protects a method for preparing the electron donor-acceptor conjugated polymer shown in the above formula (II), which comprises the following steps: Mix with and prepare the electron donor-acceptor conjugated polymer with the structure shown in formula (II) through a polymerization reaction.

[0015] Preferably, in the method for preparing the electron donor-acceptor conjugated polymer shown in formula (II), it is obtained by reacting 1,3,6,8-tetrabromo-9H-carbazole with 1-bromo-2-(2-methoxyethoxy)ethane.

[0016] Preferably, in the method for preparing the electron donor-acceptor conjugated polymer shown in formula (II), mix with and react in the presence of a palladium catalyst, copper iodide and a base to obtain the electron donor-acceptor conjugated polymer with the structure shown in formula (II).

[0017] Preferably, in the method for preparing the electron donor-acceptor conjugated polymer shown in formula (II), the molar ratio of to

[0018] is 1:(4.05 - 4.2).

[0018] Preferably, in the method for preparing the electron donor-acceptor conjugated polymer shown in formula (II), the palladium catalyst can be tetrakis(triphenylphosphine)palladium and / or bis(triphenylphosphine)palladium chloride.

[0019] Preferably, in the method for preparing the electron donor-acceptor conjugated polymer shown in formula (II), the base is one or more of triethylamine, sodium carbonate and potassium carbonate.

[0020] Preferably, in the method for preparing the electron donor-acceptor conjugated polymer shown in formula (II), the reaction temperature is 70 - 90 °C and the reaction time is 24 - 48 hours.

[0021] Preferably, in the method for preparing the electron donor-acceptor conjugated polymer shown in formula (II), the reaction atmosphere is an inert atmosphere. Specifically, the reaction atmosphere is a nitrogen atmosphere and / or an argon atmosphere.

[0022] Preferably, in the preparation method of the electron donor-acceptor conjugated polymer represented by formula (II), the reaction is carried out in an organic solvent, and the organic solvent is one or more of dimethylacetamide, N-methylpyrrolidone, and dimethylformamide.

[0023] Preferably, in the preparation method of the electron donor-acceptor conjugated polymer represented by formula (II), after the reaction, a post-treatment operation may further be included, and the post-treatment sequentially includes ultrasonic treatment, centrifugation, washing, and vacuum drying.

[0024] The present invention also protects the preparation method of the electron donor-acceptor conjugated polymer represented by formula (III) above, including the following steps: Mix with and prepare the electron donor-acceptor conjugated polymer with the structure represented by formula (III) through a polymerization reaction.

[0025] Preferably, in the preparation method of the electron donor-acceptor conjugated polymer represented by formula (III), it is obtained by reacting 1,3,6,8-tetrabromo-9H-carbazole with 1-bromotridecane.

[0026] Preferably, in the preparation method of the electron donor-acceptor conjugated polymer represented by formula (III), mix with and react in the presence of a palladium catalyst, copper(I) iodide, and a base to obtain the electron donor-acceptor conjugated polymer represented by formula (III).

[0027] Preferably, in the preparation method of the electron donor-acceptor conjugated polymer represented by formula (III), the molar ratio of is 1:(4.05 - 4.2).

[0028] Preferably, in the preparation method of the electron donor-acceptor conjugated polymer represented by formula (III), the palladium catalyst may be tetrakis(triphenylphosphine)palladium and / or bis(triphenylphosphine)palladium chloride.

[0029] Preferably, in the preparation method of the electron donor-acceptor conjugated polymer represented by formula (III), the base is one or more of triethylamine, sodium carbonate, and potassium carbonate.

[0030] Preferably, in the preparation method of the electron donor-acceptor conjugated polymer represented by formula (III), the reaction temperature is 70 - 90 °C, and the reaction time is 24 - 48 hours.

[0031] Preferably, in the preparation method of the electron donor-acceptor conjugated polymer represented by formula (III), the reaction atmosphere is an inert atmosphere. Specifically, the reaction atmosphere is a nitrogen atmosphere and / or an argon atmosphere.

[0032] Preferably, in the preparation method of the electron donor-acceptor conjugated polymer represented by formula (III), the reaction is carried out in an organic solvent, and the organic solvent is one or more of dimethylacetamide, N-methylpyrrolidone, and dimethylformamide.

[0033] Preferably, in the preparation method of the electron donor-acceptor conjugated polymer represented by formula (III), after the reaction, a post-treatment operation can also be included, and the post-treatment sequentially includes ultrasonic treatment, centrifugation, washing, and vacuum drying.

[0034] The present invention also protects the application of the electron donor-acceptor conjugated polymer described in any one of the above in photocatalytic production of hydrogen peroxide as a photocatalyst.

[0035] The present invention also protects the application of the electron donor-acceptor conjugated polymer described in any one of the above as a photocatalyst in promoting the generation of photo-generated carriers.

[0036] The present invention also protects the application of the electron donor-acceptor conjugated polymer described in any one of the above as a photocatalyst in reducing the exciton binding energy.

[0037] The present invention also protects a method for photocatalytic production of hydrogen peroxide, which includes the following steps: adding the electron donor-acceptor conjugated polymer described in any one of the above to water and irradiating with light to generate hydrogen peroxide.

[0038] Compared with the prior art, the beneficial effects of the present invention are: The present invention discloses a conjugated polymer having an alternating connection structure of an electron donor - electron acceptor, wherein the electron donor and the electron acceptor are connected by an alkyne electron bridge, the electron donor unit is a carbazole with an oligoether chain or an alkyl chain, and the electron acceptor unit is anthraquinone.

[0039] In the electron donor-acceptor conjugated polymer of the present invention, after the electron bridge and the electron acceptor obtain electrons under light irradiation, they can serve as active sites for oxygen reduction, and selectively reduce oxygen to hydrogen peroxide with high selectivity. It is an excellent photocatalyst and can improve the yield of photocatalytic production of hydrogen peroxide. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 is the nuclear magnetic resonance ( 13 C-NMR) spectrum of the electron donor-acceptor conjugated polymers of Example 1, Example 2, and Comparative Example 1.

[0041] Figure 2 is the diffuse reflectance infrared spectrum of the electron donor-acceptor conjugated polymers of Example 1, Example 2, and Comparative Example 1.

[0042] Figure 3 is the Raman spectrum of the electron donor-acceptor conjugated polymers of Example 1, Example 2, and Comparative Example 1.

[0043] Figure 4 XRD patterns of the electron donor-acceptor conjugated polymers of Example 1, Example 2 and Comparative Example 1.

[0044] Figure 5 Scanning electron microscopy characterization images of the electron donor-acceptor conjugated polymers of Example 1, Example 2 and Comparative Example 1.

[0045] Figure 6 Transmission electron microscopy characterization images of the electron donor-acceptor conjugated polymers of Example 1, Example 2 and Comparative Example 1.

[0046] Figure 7 Transient photocurrent response characterization images of the electron donor-acceptor conjugated polymers of Example 1, Example 2 and Comparative Example 1 under an argon atmosphere.

[0047] Figure 8 Variable-temperature photoluminescence spectra of the electron donor-acceptor conjugated polymers of Example 1, Example 2 and Comparative Example 1.

[0048] Figure 9 Graph of the change in variable-temperature photoluminescence intensity with temperature for the electron donor-acceptor conjugated polymers of Example 1, Example 2 and Comparative Example 1. Detailed implementation manners

[0049] To describe the technical solution of the present invention more clearly and completely, the following further details the present invention 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 rights of the present invention.

[0050] Example 1 An electron donor-acceptor conjugated polymer having the structure shown in the following formula (II): Formula (II).

[0051] The preparation method of the above electron donor-acceptor conjugated polymer includes the following steps: Step S1. Add 100 mg of 1,3,6,8-tetrabromo-9H-carbazole and 149 mg of potassium carbonate to 5 mL of N,N-dimethylformamide. After stirring at room temperature for 30 minutes, add 20 mg of 1-bromo-2-(2-methoxyethoxy)ethane. After the reaction ends in 12 h, a white precipitate is obtained, and the monomer product is filtered out. The structural formula is as follows: .

[0052] 1 H NMR (400 MHz, Chloroform- d) δ 8.07 (d, J = 4 Hz, 2H), 7.81 (d, J =2 Hz, 2H), 5.43-5.46 (m, 2H), 3.79-3.83 (m, 2H), 3.47-3.50 (m, 2H), 3.34-3.37(m, 2H), 3.26 (s, 3H). Step S2. Dissolve the monomer prepared in Step S1 (50 mg) and 2,6 - diethynyl - 9,10 - anthraquinone (96 mg) in 8 mL of dimethylformamide (DMF) under an argon atmosphere. Add (PPh)2PdCl2 (27 mg), CuI (3.5 mg), and triethylamine (8 mL) to the solution. The reaction mixture is stirred at 80 °C for 48 hours. After cooling, it is ultrasonicated in DMF for 30 minutes, then centrifuged, and ultrasonically washed three times with ethanol. Then the catalyst is filtered and dried under vacuum at 60 °C to obtain the electron donor - acceptor conjugated polymer shown in formula (II), named PEG - alky - AQ. After analysis, the degree of polymerization of the polymer is distributed from 1 to 100.

[0053] Example 2 An electron donor - acceptor conjugated polymer has the structure shown in the following formula (III): Formula (III).

[0054] The preparation method of the above - mentioned electron donor - acceptor conjugated polymer includes the following steps: Step S1. Add 100 mg of 1,3,6,8 - tetrabromo - 9H - carbazole and 149 mg of potassium carbonate to 5 mL of N,N - dimethylformamide. After stirring at room temperature for 30 minutes, add 27 mg of 1 - bromotridecane. After the reaction ends in 12 h, the monomer product is purified, and the structural formula is as follows: .

[0055] 1 H NMR (600 MHz, Chloroform - d ) δ 8.07 (d, J = 6 Hz, 2H), 7.81 (d, J =6 Hz, 2H), 5.11 - 5.16 (m, 2H), 1.80 (t, J = 24 Hz, 2H), 1.27 (s, 20H), 0.90(t, J = 18 Hz, 3H). Step S2. Dissolve the monomer (50 mg) prepared in Step S1 and 2,6-diethynyl-9,10-anthraquinone (90 mg) in 8 mL of dimethylformamide (DMF) under an argon atmosphere. Add (PPh)2PdCl2 (27 mg), CuI (3.5 mg), and triethylamine (8 mL) to the solution. The reaction mixture is stirred at 80 °C for 48 hours. After cooling, it is sonicated in DMF for 30 minutes, then centrifuged and ultrasonically washed three times with ethanol. Then the catalyst is filtered and dried in vacuo at 60 °C to obtain the electron donor-acceptor conjugate polymer shown in formula (III), named C13-alky-AQ. After analysis, the degree of polymerization of the polymer is distributed from 1 to 100.

[0056] Example 3 A method for photocatalytic production of hydrogen peroxide, comprising the following steps: Ultrasonically disperse 1 mg of the electron donor-acceptor conjugate polymer of Example 1 in 50 mL of pure water for 30 min, stir and irradiate with a xenon lamp to simulate sunlight, with a light power of 100 mW / cm 2 , and perform a photocatalytic hydrogen peroxide production test. After 1 h of testing, the hydrogen peroxide production rate is 2549 μmol·g -1 ·h -1 .

[0057] Example 4 A method for photocatalytic production of hydrogen peroxide, comprising the following steps: Ultrasonically disperse 1 mg of the electron donor-acceptor conjugate polymer of Example 2 in 50 mL of pure water for 30 min, stir and irradiate with a xenon lamp to simulate sunlight, with a light power of 100 mW / cm 2 , and perform a photocatalytic hydrogen peroxide production test. After 1 h of testing, the hydrogen peroxide production rate is 2452 μmol·g -1 ·h -1 .

[0058] Comparative Example 1 An electron donor-acceptor conjugate polymer having the structure shown in the following formula (IV): Formula (IV).

[0059] The preparation method of the above electron donor-acceptor conjugate polymer comprises the following steps: 1,3 - Diethynylbenzene (100 mg) and 2,6 - dibromoanthraquinone (290 mg) were dissolved in 8 mL of dimethylformamide (DMF) under an argon atmosphere. (PPh)2PdCl2 (55 mg), CuI (7 mg), and triethylamine (8 mL) were added to the solution. The reaction mixture was stirred at 80 °C for 48 hours. After cooling, it was sonicated in DMF for 30 minutes, then centrifuged and ultrasonically washed three times with ethanol. Then the catalyst was filtered and dried under vacuum at 60 °C to obtain the electron donor - acceptor conjugated polymer shown in formula (IV), named Benz - alky - AQ.

[0060] 1 mg of the electron donor - acceptor conjugated polymer of formula (IV) above was ultrasonically dispersed in 50 mL of pure water for 30 min, stirred and irradiated with a xenon lamp to simulate sunlight, with a light power of 100 mW / cm 2 , and the photocatalytic hydrogen peroxide production was tested. After 1 h of testing, the hydrogen peroxide yield was 1423 μmol·g -1 ·h -1 .

[0061] Performance Test: The electron donor - acceptor conjugated polymers of Example 1, Example 2, and Comparative Example 1 were tested using a solid - state nuclear magnetic resonance spectrometer, an infrared spectrometer, a Raman spectrometer, an X - ray powder diffractometer, a scanning electron microscope, and a transmission electron microscope respectively. The test results are as follows: Figure 1 is the nuclear magnetic resonance ( 13 C - NMR) spectrum of the electron donor - acceptor conjugated polymers of Example 1, Example 2, and Comparative Example 1. Figure 1 In (a) of 13 is the nuclear magnetic resonance ( Figure 1 C - NMR) spectrum of the electron donor - acceptor conjugated polymer of Example 1. 13 is the nuclear magnetic resonance ( Figure 1 C - NMR) spectrum of the electron donor - acceptor conjugated polymer of Example 2. 13 is the nuclear magnetic resonance (

[0062] Figure 2 is the diffuse - reflectance infrared spectrum of the electron donor - acceptor conjugated polymers of Example 1, Example 2, and Comparative Example 1.

[0063] Figure 3 is the Raman spectrum of the electron donor - acceptor conjugated polymers of Example 1, Example 2, and Comparative Example 1.

[0064] Figure 4 is the XRD pattern of the electron donor - acceptor conjugated polymers of Example 1, Example 2, and Comparative Example 1.

[0065] Figure 5 Scanning electron microscope characterization diagrams of the electron donor-acceptor conjugated polymers of Example 1, Example 2, and Comparative Example 1. Among them, Figure 5 in (a) is the scanning electron microscope characterization diagram of the electron donor-acceptor conjugated polymer of Example 1. Figure 5 in (b) is the scanning electron microscope characterization diagram of the electron donor-acceptor conjugated polymer of Example 2. Figure 5 in (c) is the scanning electron microscope characterization diagram of the electron donor-acceptor conjugated polymer of Comparative Example 1.

[0066] Figure 6 Transmission electron microscope characterization diagrams of the electron donor-acceptor conjugated polymers of Example 1, Example 2, and Comparative Example 1. Figure 6 in (a) is the transmission electron microscope characterization diagram of the electron donor-acceptor conjugated polymer of Example 1. Figure 6 in (b) is the transmission electron microscope characterization diagram of the electron donor-acceptor conjugated polymer of Example 2. Figure 6 in (c) is the transmission electron microscope characterization diagram of the electron donor-acceptor conjugated polymer of Comparative Example 1.

[0067] The characteristic signals of the alkynyl groups are determined by solid-state 13 13 13 C nuclear magnetic resonance ( 13 13 Figure 1 C-NMR) spectroscopy, Fourier transform infrared spectroscopy (FT-IR), and Raman spectroscopy. Specifically, -1 the signal at ≈90 ppm in the 13 Figure 2 C-NMR ( -1 ), the signal at ≈2210 cm Figure 3 −1 in the FT-IR spectrum ( 13 ), and the signal at 2200 cm Figure 1 −1 in the Raman spectrum ( -1 ) determine the characteristic signals of the alkynyl groups. In addition, Figure 2 the signal peak of the keto carbon at ≈180 ppm in the 13 13 C NMR spectrum ( 13 ), the stretching vibration signal peak of C=O at ~1670 cm Figure 1), all of the above results confirmed the successful synthesis of the catalyst. The powder X-ray diffraction (PXRD) pattern ( Figure 4 ), the scanning electron microscope (SEM) image ( Figure 5 ), and the transmission electron microscope (TEM) image ( Figure 6 ) showed that all the photocatalysts exhibited the layered characteristics of amorphous carbon. The successful polymerization of the electron donor-acceptor conjugated polymers of Example 1, Example 2, and Comparative Example 1 was determined by the above various analysis methods.

[0068] Figure 7 Figure Figure 7 is the transient photocurrent response characterization diagram of the electron donor-acceptor conjugated polymers of Example 1, Example 2, and Comparative Example 1 under an argon atmosphere. Through the analysis of

[0069] , it can be seen that, compared with Comparative Example 1, the amount of photo-generated carriers of the electron donor-acceptor conjugated polymers of Example 1 and Example 2 increased significantly. Figure 8 and Figure 9 relevant tests were carried out to further explore the reason for the increase in photo-generated carriers. Figure 8 Figure Figure 8 shows the temperature-dependent photoluminescence (PL) spectra of the electron donor-acceptor conjugated polymers of Example 1, Example 2, and Comparative Example 1. Figure 8 In Figure 8 , (a) is the temperature-dependent photoluminescence (PL) spectrum of the electron donor-acceptor conjugated polymer of Example 1.

[0070] In the temperature range of 200 K to 300 K, the PL intensity of the polymer gradually decreased with the increase of temperature. Further, the Arrhenius equation was used to fit the variation law of fluorescence intensity with temperature:

[0071] where T is the thermodynamic temperature, in Kelvin (K); I0 is the fluorescence intensity at the initial temperature; I(T) represents the fluorescence intensity of the photocatalyst at temperature T; A is the pre-exponential factor; E a is the exciton binding energy; k B is the Boltzmann constant. A and E a were obtained by fitting the temperature-intensity relationship diagram.

[0072] Figure 9 Figure Figure 9Among them, (a) is the graph showing the variation of the temperature-dependent photoluminescence intensity of the electron donor-acceptor conjugated polymer of Example 1 with temperature. Figure 9 Among them, (b) is the graph showing the variation of the temperature-dependent photoluminescence intensity of the electron donor-acceptor conjugated polymer of Example 2 with temperature. Figure 9 Among them, (c) is the graph showing the variation of the temperature-dependent photoluminescence intensity of the electron donor-acceptor conjugated polymer of Comparative Example 1. From Figure 9 It can be seen that the exciton binding energies (E a ) of the electron donor-acceptor conjugated polymers (PEG-alky-AQ) of Example 1 and (C13-alky-AQ) of Example 2 are 74 meV and 52 meV respectively, which are much smaller than 184 meV of the electron donor-acceptor conjugated polymer (Benz-alky-AQ) of Comparative Example 1. This result indicates that compared with the electron donor-acceptor conjugated polymer (Benz-alky-AQ) of Comparative Example 1, the electron donor-acceptor conjugated polymers (PEG-alky-AQ) of Example 1 and (C13-alky-AQ) of Example 2 have lower exciton binding energies, and this property promotes the more efficient conversion of excitons into photo-generated carriers.

[0073] It can be seen from Example 1 and Example 2 of the present invention that the electron donor-acceptor conjugated polymer containing an oligoether chain-modified carbazole group as an electron donor in Example 1 of the present invention has a higher hydrogen peroxide production rate under the conditions of pure water in the open air without a sacrificial agent and simulated sunlight.

[0074] It can be seen from the above data that compared with the electron donor-acceptor conjugated polymer (Benz-alky-AQ) of Comparative Example 1, the electron donor-acceptor conjugated polymers (PEG-alky-AQ) of Example 1 and (C13-alky-AQ) of Example 2 respectively modify the carbazole group by introducing an oligoether chain and an alkyl chain, effectively reducing the exciton binding energy. The reduction of the exciton binding energy promotes more excitons to dissociate into photo-generated carriers, thereby significantly improving the hydrogen peroxide production rate.

[0075] 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 on the basis of the above description. It is not necessary and impossible to enumerate all the implementation manners here. Any modifications, equivalent substitutions, 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. An electron donor-conjugated polymer, characterized in that, It has the structure shown in the following formula (I): Formula (I); Among them, is an electron donor unit; is an electron acceptor unit; is an electron bridge; the degree of polymerization n = 1 to 100; The electron donor unit is of formula (a-1) or (a-2); Formula (a-1); Formula (a-2); In formula (a-2), R is a straight-chain alkyl group with 12 to 14 carbon atoms; The electron acceptor unit is of formula (b): Formula (b); 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.

2. The electron acceptor conjugated polymer according to claim 1, wherein It has the structure shown in the following formula (II): Formula (II).

3. The electron acceptor conjugated polymer according to claim 1, wherein It has the structure shown in the following formula (III): Formula (III).

4. The preparation method of the electron acceptor conjugated polymer according to claim 2, characterized in that, including the following steps: combining with to prepare an electron acceptor conjugated polymer with the structure shown in formula (II) through a polymerization reaction.

5. The preparation method of the electron acceptor conjugated polymer according to claim 4, wherein, It is obtained by reacting 1,3,6,8-tetrabromo-9H-carbazole with 1-bromo-2-(2-methoxyethoxy)ethane.

6. The preparation method of the electron acceptor conjugated polymer according to claim 3, characterized in that, It includes the following steps: Mix and and prepare an electron acceptor conjugated polymer with the structure shown in formula (III) through a polymerization reaction.

7. The preparation method of the electron acceptor conjugated polymer according to claim 6, characterized in that, Obtained by reacting 1,3,6,8-tetrabromo-9H-carbazole with 1-bromotridecane.

8. Use of the electron donor-acceptor conjugated polymer according to any one of claims 1 to 3 in photocatalytic production of hydrogen peroxide as a photocatalyst.

9. Use of the electron donor-acceptor conjugated polymer according to any one of claims 1 to 3 as a photocatalyst in promoting the generation of photo-generated carriers.

10. A method for photocatalytic production of hydrogen peroxide, characterized in that, It includes the following steps: adding the electron donor-acceptor conjugated polymer according to any one of claims 1 to 3 into water and irradiating with light to produce hydrogen peroxide.

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