Photocatalyst for regeneration of coenzyme NADH and preparation method thereof

Abstract

The present invention discloses a photocatalyst for the regeneration of coenzyme NADH and a preparation method thereof, wherein the photocatalyst is a donor-π-acceptor type conjugated organic polymer, with a triazine-based ligand as an acceptor unit and a heterocyclic ligand as a donor unit, wherein the molar ratio of the triazine-based ligand to the heterocyclic ligand is 1:(1-2), the triazine-based ligand raw material selects 2,4,6-trimethyl-1,3,5-triazine, and the heterocyclic ligand raw material selects a heterocyclic diformaldehyde containing a furan or thiophene structure. The photocatalyst is prepared by a solvothermal method through a Knoevenagel aldol condensation reaction, the reaction solvent selects a mixed solvent of n-butanol and o-dichlorobenzene or a mixed solvent of mesitylene and 1,4-dioxane, and the catalyst used in the reaction selects at least one of trifluoroacetic acid, potassium hydroxide, 1,8-diazabicycloundecane-7-ene, sodium hydroxide, and cesium carbonate. The developed photocatalyst has a donor-π-acceptor type conjugated structure, and has high catalytic activity, high selectivity, good stability, and easy separation and recovery for the regeneration of coenzyme NADH.

Description

Technical Field

[0001] The present invention relates to the technical field of photocatalysts, in particular to a photocatalyst for regenerating coenzyme NADH and the preparation of the photocatalyst. Background Art

[0002] Oxidoreductases, a general term for enzymes that catalyze redox reactions between two molecules, are an important class of biocatalysts. However, many oxidoreductases require the expensive coenzyme NADH to catalyze reactions, which limits their industrial application. Therefore, developing efficient and environmentally friendly coenzyme NADH regeneration technologies is crucial to addressing this issue. Common coenzyme regeneration methods include biocatalysis, chemical catalysis, electrocatalysis, and photocatalysis. Photocatalysis, which uses solar energy as a power source, offers advantages such as being green, environmentally friendly, and sustainable, and holds broad development prospects.

[0003] The specific process of photocatalytic coenzyme NADH regeneration is generally as follows: under light conditions, the photocatalyst is excited by light to generate electrons and holes, the photogenerated holes are consumed by the electron sacrificial agent, and the photogenerated electrons and protons from the sacrificial agent are transferred to NAD through a mediator (such as a rhodium complex). + , reducing it to NADH. The regeneration efficiency of coenzyme NADH is often limited by the charge separation efficiency of the photocatalyst and the light absorption range of the photocatalyst. Traditional photocatalysts usually have problems such as low charge separation efficiency or narrow light absorption range. For example, although carbon nitride (C3N4) has a wide light absorption range and can utilize visible light, its photogenerated carriers and holes recombine too quickly, resulting in low photocatalytic efficiency; the more common photocatalyst titanium dioxide has a high photoelectric conversion efficiency, but its light absorption range is narrow and is limited to the ultraviolet light region. It cannot utilize visible light, which limits its application. Therefore, the development of a photocatalyst with a wide light absorption range, high charge separation efficiency and good stability for catalyzing the efficient regeneration of coenzyme NADH is an urgent problem to be solved. Summary of the Invention

[0004] In order to address the shortcomings of the existing technology, the present invention develops an organic polymer with a donor-π-acceptor type conjugated structure as a photocatalyst for the regeneration of coenzyme NADH. The catalyst has high catalytic activity for the regeneration of coenzyme NADH, high selectivity, good stability, easy separation and recovery, and is environmentally friendly and pollution-free.

[0005] The photocatalyst for regenerating the coenzyme NADH of the present invention is a donor-π-acceptor type conjugated organic polymer, with a triazine ligand as an acceptor unit and a heterocyclic ligand as a donor unit. The molar ratio of the triazine ligand to the heterocyclic ligand is 1:1 to 1:2. The raw material of the triazine ligand is 2,4,6-trimethyl-1,3,5-triazine, and the raw material of the heterocyclic ligand is a heterocyclic dicarboxaldehyde containing a furan or thiophene structure.

[0006] The regeneration of coenzyme NADH requires not only the regeneration rate but also the selectivity of the regenerated coenzyme NADH. Based on the comprehensive requirements of both aspects, the present invention abandons the existing photocatalyst materials used for coenzyme NADH, such as carbon nitride and titanium dioxide, and innovatively uses a donor-π-acceptor type conjugated structure organic polymer as a photocatalyst for the regeneration of coenzyme NADH. After comprehensive experimental screening based on the charge separation efficiency and light absorption range after the donor unit and the acceptor unit are adapted, it is determined that a triazine ligand with strong electron-withdrawing ability is used as the acceptor unit and a heterocyclic ligand with strong electron-donating ability is used as the donor unit. In addition, a 2,4,6-trimethyl-1-[3-(2-[2-(2-piperidin-1-yl)-1-[ ... ,3,5-triazine is used as the triazine-based ligand raw material, and electron-rich heterocyclic dicarboxaldehyde containing furan, thiophene or its derivative structure is used as the matching donor unit raw material, so that the obtained photocatalyst has high catalytic activity, which can improve the regeneration rate of coenzyme NADH, and further make the regenerated coenzyme NADH have higher 1,4-NADH selectivity. Specifically, the photocatalytic NADH regeneration system is coupled with the hydrogenation reaction catalyzed by the old yellow enzyme to realize the light-enzyme coupling catalytic hydrogenation reduction of cycloenone, and convert cyclohexenone into cyclohexanone under visible light excitation, so that the cyclohexanone yield can reach up to 69.7% after 4 hours of reaction, making the regenerated coenzyme NADH more valuable in application.

[0007] As a limitation of the above technical solution, the heterocyclic ligand raw material is selected from any one of 2,5-furandicarboxaldehyde, 2,5-thiophenedicarboxaldehyde, [2,2']-bithiophene-5,5'-dicarboxaldehyde, and thieno[3,2-B]thiophene-2,5-dicarboxaldehyde.

[0008] As a limitation of the above technical solution, a donor-π-acceptor type conjugated organic polymer is prepared by a solvothermal method through a Knoevenagel aldol condensation reaction of a triazine-based ligand raw material and a heterocyclic ligand raw material, the reaction solvent is a mixed solvent of n-butanol and o-dichlorobenzene or a mixed solvent of mesitylene and 1,4-dioxane, and the catalyst used in the reaction is at least one of trifluoroacetic acid, potassium hydroxide, 1,8-diazabicycloundec-7-ene (DBU), sodium hydroxide, and cesium carbonate.

[0009] As a limitation of the above technical solution, the reaction solvent is a mixed solvent of n-butanol and o-dichlorobenzene, and the catalyst used in the reaction is potassium hydroxide.

[0010] When potassium hydroxide is used as a catalyst and a mixture of n-butanol and o-dichlorobenzene is used as a solvent, a catalyst with the best coenzyme regeneration effect can be obtained.

[0011] As a limitation of the above technical solution, the photocatalyst is a donor-π-acceptor type conjugated organic polymer, which is used to catalyze the regeneration of coenzyme NADH under visible light irradiation conditions of λ>420nm.

[0012] Further refinements were made to the preferred heterocyclic dicarboxaldehyde species for the heterocyclic ligand, as well as the catalyst and solvent used in the photocatalyst preparation process, which uses triazine-based ligands and heterocyclic ligands as monomers for the reaction, to improve the catalytic activity, selectivity, and stability of the photocatalyst. Furthermore, the illumination conditions for the regeneration of the coenzyme NADH were refined to improve the regeneration process.

[0013] At the same time, the present invention also provides a method for preparing the photocatalyst for regenerating the coenzyme NADH as described above, comprising the following steps:

[0014] a. Disperse 0.1 g of potassium hydroxide in 2-5 mL of n-butanol solution, and ultrasonicate at room temperature for 5-10 minutes until the potassium hydroxide is completely dissolved to obtain a potassium hydroxide-n-butanol solution;

[0015] b. Dispersing 0.1-0.5 mmol of a triazine-based ligand raw material and a corresponding amount of a heterocyclic ligand raw material in 1-4 mL of a mixed solvent, and sonicating for 5-20 minutes until completely dissolved to obtain a monomer solution; the mixed solvent is prepared by mixing o-dichlorobenzene and n-butanol in a volume ratio of 3:(1-9);

[0016] c. Add 0.1-0.5 mL of potassium hydroxide-n-butanol solution to the monomer solution obtained in step b, ultrasonicate for 2-10 minutes to mix the solution evenly, then evacuate the reaction system and fill it with nitrogen to completely remove the air, and then react in a vacuum at 80-150° C. for 1-5 days. After the reaction is completed, filter the reaction, and wash the resulting precipitate with methanol, tetrahydrofuran, and dichloromethane, respectively. Finally, dry the product in a vacuum at 40-120° C. for 12-24 hours to obtain a photocatalyst donor-π-acceptor type conjugated organic polymer.

[0017] As a limitation of the above technical solution, the vacuum reaction condition of step c is a vacuum degree of 0.2 to 0.4 MPa.

[0018] As a limitation of the above technical solution, the mass concentration of potassium hydroxide in the potassium hydroxide-n-butanol solution is 0.05 g / mL.

[0019] As a limitation of the above technical solution, the volume ratio of the potassium hydroxide-n-butanol solution used in the preparation method to the n-butanol and o-dichlorobenzene in the mixed solvent is 1:(3-4):(1-2).

[0020] The optimized conditions for the preparation of the photocatalyst are as follows: 0.1 g of potassium hydroxide is dispersed in 2 mL of n-butanol solution, and ultrasonicated at room temperature for 5 to 10 minutes to obtain a potassium hydroxide-n-butanol solution; 0.1 to 0.3 mmol of triazine-based ligand raw material and the corresponding amount of heterocyclic ligand raw material are dispersed in 1 to 2 mL of a mixed solvent of o-dichlorobenzene and n-butanol to obtain a monomer solution, wherein the molar ratio of the triazine-based ligand to the heterocyclic ligand is 1:1.5, the volume ratio of o-dichlorobenzene to n-butanol in the mixed solvent is 1:1.77, and ultrasonicated for 5 to 10 minutes. minutes until the ligand is completely dissolved; 0.3-0.4 mL of potassium hydroxide-n-butanol solution is added to the above monomer solution, and ultrasonication is continued for 3-5 minutes. The reaction tube is then evacuated and filled with nitrogen (0.2 MPa) three times to ensure that the air is completely removed. The reaction is carried out in a vacuum at 110-130° C. for 3 days. After the reaction is completed, it is filtered, and the resulting precipitate is washed with methanol, tetrahydrofuran and dichloromethane three times each. Finally, the product is vacuum dried at 60° C. for 12 hours to obtain a photocatalyst donor-π-acceptor type conjugated organic polymer.

[0021] The present invention adopts a solvothermal method to convert a triazine ligand and a heterocyclic ligand into a donor-π-acceptor type conjugated organic polymer photocatalytic material connected by a carbon-carbon double bond through a Knoevenagel condensation reaction. The photocatalytic NADH regeneration material can be improved in charge separation efficiency, reduce photogenerated electron-hole recombination, and catalyze the regeneration of NADH under the excitation of visible light with λ>420nm. The material has high efficiency and good cyclic stability, and the NADH regeneration yield can reach up to 85.4% after half an hour of photoirradiation reaction. Since only 1,4-NADH can be utilized by the enzyme, in order to further investigate the selectivity of NADH obtained by photocatalysis, a coenzyme-dependent old yellow enzyme is selected, and the photocatalytic NADH regeneration system is coupled with a hydrogenation reaction catalyzed by the old yellow enzyme. The activity of the photocatalytically regenerated coenzyme NADH is evaluated, making the obtained photocatalyst more practical. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 , is a Fourier transform infrared spectrum of the photocatalyst DFF-DAP of Example 1 of the present invention;

[0023] Figure 2 , is the Fourier transform infrared spectrum of the photocatalyst DFT-DAP of Example 2 of the present invention;

[0024] Figure 3 , is a Fourier transform infrared spectrum of the photocatalyst TTD-DAP of Example 3 of the present invention;

[0025] Figure 4 , is a Fourier transform infrared spectrum of the photocatalyst DPD-DAP of Example 4 of the present invention;

[0026] Figure 5, is a Fourier transform infrared spectrum of the photocatalyst DFB-DAP of Comparative Example 1 of the present invention;

[0027] Figure 6 , is the GC chromatogram of the substrate standard in the cyclohexanone yield detection;

[0028] Figure 7 , is the GC chromatogram of the product standard in the cyclohexanone yield detection;

[0029] Figure 8 , is the GC chromatogram of the DFF-DAP light-enzyme coupled catalytic reaction system in Example 1. DETAILED DESCRIPTION

[0030] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0031] The raw materials involved in the following examples and comparative examples are typical products purchased from the market.

[0032] Example

[0033] The following examples relate to the preparation of the photocatalyst of the present invention for the regeneration of the coenzyme NADH.

[0034] Example 1

[0035] The preparation of the photocatalyst donor-π-acceptor type conjugated organic polymer DFF-DAP is as follows:

[0036] a. Disperse 0.1 g of potassium hydroxide in 2 mL of n-butanol solution and ultrasonicate at room temperature for 5 minutes to obtain a potassium hydroxide-n-butanol solution with a concentration of 0.05 g / mL;

[0037] b. Based on 0.1 mmol of 2,4,6-trimethyl-1,3,5-triazine as a benchmark, the molar ratio of the triazine-based ligand raw material 2,4,6-trimethyl-1,3,5-triazine to the heterocyclic ligand raw material 2,5-furandicarboxaldehyde is 1:1.5. 0.6 mL of o-dichlorobenzene and 1.06 mL of n-butanol are added to a branched reaction tube to obtain a mixed solvent. 0.0123 g of 1,3,5-trimethyltriazine and 0.0186 g of 2,5-furandicarboxaldehyde are dispersed in the mixed solvent in the branched reaction tube, and ultrasonicated for 5 minutes until the ligand is completely dissolved to obtain a monomer solution.

[0038] c. Add 0.34 mL of the potassium hydroxide-n-butanol solution prepared in step a to the monomer solution in step b, continue ultrasonication for 5 minutes, then evacuate the branched reaction tube and fill it with nitrogen (0.2 MPa) three times to meet the requirements to ensure that the air is completely removed. Then maintain the vacuum state and conduct solvent thermal reaction at 120°C for 3 days. After the reaction is completed, filter and wash the resulting precipitate with solvents of different polarities: methanol, tetrahydrofuran and dichloromethane three times each. The unreacted different ligands and some oligomers are removed by washing with different solvents. Then, dry in vacuum at 60°C for 24 hours to obtain the donor-π-acceptor type conjugated porous organic polymer photocatalyst DFF-DAP. The successful preparation of DFF-DAP was verified by Fourier transform infrared spectroscopy (FT-IR). The results are as follows: Figure 1 shown.

[0039] Example 2

[0040] The preparation of the donor-π-acceptor type conjugated organic polymer photocatalyst DFT-DAP is as follows:

[0041] Based on 0.1mmol of 2,4,6-trimethyl-1,3,5-triazine, the molar ratio of 2,5-thiophene dicarboxaldehyde was 1:1.6. 0.0123g of 2,4,6-trimethyl-1,3,5-triazine and 0.022g of 2,5-thiophene dicarboxaldehyde were dispersed in a mixed solvent of 0.6mL of o-dichlorobenzene and 1.06mL of n-butanol in a branched reaction tube. The other preparation operations were the same as in Example 1 to obtain a donor-π-acceptor type conjugated organic polymer photocatalyst DFT-DAP. The successful preparation of DFT-DAP was verified by Fourier transform infrared spectroscopy (FT-IR). The results are as follows: Figure 2 shown.

[0042] Example 3

[0043] The preparation of the donor-π-acceptor type conjugated organic polymer photocatalyst TTD-DAP is as follows:

[0044] Based on 0.1mmol of 2,4,6-trimethyl-1,3,5-triazine, the molar ratio of 2,4,6-trimethyl-1,3,5-triazine to [2,2']-bithiophene-5,5'-dicarboxaldehyde was 1:1.7. 0.0123g of 2,4,6-trimethyl-1,3,5-triazine and 0.037g of [2,2']-bithiophene-5,5'-dicarboxaldehyde were dispersed in a mixed solvent of 0.6mL of o-dichlorobenzene and 1.06mL of n-butanol in a branched reaction tube. The other preparation operations were the same as in Example 1 to obtain a donor-π-acceptor type conjugated organic polymer photocatalyst TTD-DAP. The successful preparation of TTD-DAP was verified by Fourier transform infrared spectroscopy (FT-IR). The results are as follows: Figure 3 shown.

[0045] Example 4

[0046] The preparation of the donor-π-acceptor type conjugated organic polymer photocatalyst DPD-DAP is as follows:

[0047] Based on 0.1 mmol of 2,4,6-trimethyl-1,3,5-triazine, the molar ratio of 2,4,6-trimethyl-1,3,5-triazine to thieno[3,2-B]thiophene-2,5-dicarboxaldehyde was 1:1.7. 0.0123 g of 2,4,6-trimethyl-1,3,5-triazine and 0.033 g of thieno[3,2-B]thiophene-2,5-dicarboxaldehyde were dispersed in a mixed solvent of 0.6 mL of o-dichlorobenzene and 1.06 mL of n-butanol in a branched reaction tube. The other steps were the same as in Example 1 to obtain a donor-π-acceptor type conjugated organic polymer photocatalyst DPD-DAP. The successful preparation of DPD-DAP was verified by FT-IR, and the results were as follows: Figure 4 shown.

[0048] Comparative Example

[0049] The following comparative examples involve donor-π-acceptor type conjugated organic polymer photocatalysts obtained with different donor-acceptor units and different preparation conditions.

[0050] Comparative Example 1

[0051] Based on 0.1 mmol of 2,4,6-trimethyl-1,3,5-triazine, the molar ratio of 2,4,6-trimethyl-1,3,5-triazine to terephthalaldehyde was 1:1.5. 0.0123 g of 2,4,6-trimethyl-1,3,5-triazine and 0.020 g of 2,5-terephthalaldehyde were dispersed in a mixed solvent of 0.6 mL of o-dichlorobenzene and 1.06 mL of n-butanol in a branched reaction tube. The other steps were the same as in Example 1 to obtain a donor-π-acceptor type conjugated organic polymer photocatalyst DFB-DAP. The successful preparation of DFB-DAP was verified by FT-IR, and the results were as follows: Figure 5 shown.

[0052] Comparative Example 2

[0053] Based on 0.1 mmol of 2,4,6-trimethyl-1,3,5-triazine and 2,5-furandicarboxaldehyde at a molar ratio of 1:1.5, 0.0123 g of 2,4,6-trimethyl-1,3,5-triazine and 0.0186 g of 2,5-furandicarboxaldehyde were dispersed in a branched reaction tube containing 0.9 mL of mesitylene, 0.9 mL of 1,4-dioxane and 0.05 mL of acetonitrile. Ultrasonication was performed for 5 minutes until the ligand was completely dissolved. 0.4 mL of trifluoroacetic acid was added and ultrasonication was continued for 5 minutes. The reaction tube was then evacuated and filled with nitrogen (0.2 MPa) three times (maintaining the vacuum state at the end). The mixture was subjected to solvothermal reaction at 120°C for 3 days. After the reaction was completed, it was filtered and the precipitate was washed three times with methanol, tetrahydrofuran and dichloromethane respectively. After vacuum drying at 60°C for 24 hours, the organic polymer photocatalyst DFF-DAP2 was obtained.

[0054] Comparative Example 3

[0055] Based on 0.1mmol of electron acceptor ligand 2,4,6-tris(tetraaminophenyl)-1,3,5-triazine, the molar ratio of the heterocyclic ligand 2,2'-bipyridine-4,4'-dicarboxaldehyde was 1:1.5, 0.0354g of 2,4,6-tris(tetraaminophenyl)-1,3,5-triazine and 0.0318g of 2,2'-Bipyridine-4,4'-dicarboxaldehyde was dispersed in a mixed solvent obtained by adding 1 mL of o-dichlorobenzene and 0.66 mL of n-butanol. The mixed solvent was ultrasonically treated for 5 minutes until the ligand was completely dissolved. 0.34 mL of potassium hydroxide n-butanol solution was added and ultrasonication was continued for 5 minutes. The reaction tube was then evacuated and filled with nitrogen (0.2 MPa) three times (maintaining the vacuum state at the end). The mixture was subjected to solvent thermal reaction at 120°C for 3 days. After the reaction was completed, it was filtered and the obtained precipitate was washed three times with methanol, tetrahydrofuran and dichloromethane respectively. After vacuum drying at 60°C for 24 hours, the organic polymer photocatalyst BDD-DAP was obtained.

[0056] In order to verify the beneficial effects of the present invention, the inventors used the photocatalysts prepared in Examples 1 to 4 and Comparative Examples 1 to 3 to catalyze the + Converted into NADH, the specific method is:

[0057] 3 mg of photocatalyst, 60 μL [Cp*Rh(bpydc)H2O] 2+ (12.5mM), 60μL NAD +After mixing the solution (1 mM) and 2.88 mL of triethanolamine solution (15 wt %), the reaction was carried out under visible light at λ>420 nm. After the reaction was kept at this temperature for 0.5 h, the reaction tube was removed. After the reaction was completed, the catalyst was separated by centrifugation. The reaction solution was filtered through a 0.45 μm organic filter membrane and detected in a microplate reader. The regeneration yield of NADH was calculated based on the absorption peak at λ=340 nm. The results are shown in Table 1.

[0058] Table 1 Photocatalytic conversion of NAD + The yield of NADH

[0059]

[0060] As can be seen from Table 1, the catalytic effect of the donor-π-acceptor type conjugated organic polymer photocatalyst on the regeneration of coenzyme NADH is affected by the donor, acceptor units and preparation conditions, among which the selection of donor and acceptor units is the key, and the preparation conditions further affect the catalytic activity of the photocatalyst.

[0061] Further on the basis of the above method, the photocatalyst prepared in Examples 1 to 4 and Comparative Example 1 was coupled with the catalytic reaction of enolate [enolate is a type of NAD(P)H-dependent oxidoreductase. It was first discovered and reported by Warburg and Christian from brewer's yeast in 1932. Subsequent studies have shown that enolate is an oxidoreductase with a flavin mononucleotide cofactor, which can asymmetrically catalyze the reduction of C=C bonds and theoretically produce up to two chiral centers. The reaction process requires the participation of the coenzyme NAD(P)H, also known as enolate reductase, which can catalyze asymmetric hydrogenation reactions including α, β-unsaturated aldehydes, ketones, carboxylic acids and their derivatives (such as esters, lactones, cyclic imides), nitriles and nitro compounds] to achieve light-enzyme coupled catalytic enone reduction, and convert cyclohexenone into cyclohexanone under visible light excitation. The specific method is:

[0062] 3 mg of photocatalyst, 60 μL [Cp*Rh(bpydc)H2O] 2+ (12.5mM), 60μL NAD + solution (50 mM), 1.82 mL triethanolamine solution (15 wt%), YqjM (3 g·L -1 )

YqjM is a member of the old yellow enzyme family, derived from Bacillus subtilisin

[0063] Regarding the detection of cyclohexanone yield, taking Example 1 as an example, the attached Figure 6 、 7 The GC chromatograms of the substrate standard and the product standard are given respectively. Figure 8 The GC chromatogram of the DFF-DAP light-enzyme coupled catalytic reaction system of Example 1 is given, and the cyclohexanone yield is calculated based on the chromatogram data. The yield calculation process of other examples is the same, and the results are shown in Table 2.

[0064] Table 2 Yields of photocatalytically coupled enzyme conversion of cyclohexenone to cyclohexanone

[0065] catalyst Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Cyclohexanone yield 69.7％ 53.7％ 50.3％ 48.4％ 45.46％

[0066] As can be seen from Table 2, the catalytic regeneration rate of coenzyme NADH and the activity of regenerated coenzyme NADH are not positively correlated. Therefore, the catalytic regeneration rate and the activity of coenzyme NADH after regeneration are comprehensively used for screening photocatalysts.

[0067] In summary, the donor-π-acceptor type conjugated organic polymer photocatalyst of the present invention has good catalytic activity and high regeneration yield for catalyzing the regeneration of coenzyme NADH, and can be used with old yellow enzyme to construct a photoenzyme coupled catalytic system to catalyze the conversion of cyclohexenone to hydrogenate cyclohexanone.

Claims

1. A photocatalyst for regenerating coenzyme NADH, characterized in that: The photocatalyst is a donor-π-acceptor type conjugated organic polymer, with a triazine ligand as an acceptor unit and a heterocyclic ligand as a donor unit. The molar ratio of the triazine ligand to the heterocyclic ligand is 1:(1-2). The raw material of the triazine ligand is 2,4,6-trimethyl-1,3,5-triazine, and the raw material of the heterocyclic ligand is any one of 2,5-furandicarboxaldehyde, 2,5-thiophenedicarboxaldehyde, [2,2']-bithiophene-5,5'-dicarboxaldehyde, and thieno[3,2-B]thiophene-2,5-dicarboxaldehyde. A donor-π-acceptor type conjugated organic polymer was prepared by a solvothermal method through a Knoevenagel aldol condensation reaction of a triazine-based ligand raw material and a heterocyclic ligand raw material. A mixed solvent of n-butanol and o-dichlorobenzene was selected as the reaction solvent, and potassium hydroxide was selected as the catalyst used in the reaction.

2. The photocatalyst for regenerating coenzyme NADH according to claim 1, characterized in that: The photocatalyst is used for catalyzing the regeneration of coenzyme NADH under the condition of visible light irradiation with λ>420nm.

3. A method for preparing a photocatalyst for regenerating coenzyme NADH, characterized in that: Using the reaction raw materials as claimed in claim 1, the preparation method comprises the following steps: a. Disperse 0.1 g of potassium hydroxide in 2-5 mL of n-butanol solution and sonicate at room temperature until the potassium hydroxide is completely dissolved to obtain a potassium hydroxide-n-butanol solution; b. Dispersing 0.1-0.5 mmol of a triazine-based ligand raw material and a corresponding amount of a heterocyclic ligand raw material in 1-4 mL of a mixed solvent, and sonicating until completely dissolved to obtain a monomer solution; the mixed solvent is prepared by mixing o-dichlorobenzene and n-butanol in a volume ratio of 3:(1-9); c. Add 0.1-0.5 mL of potassium hydroxide-n-butanol solution to the monomer solution obtained in step b, perform ultrasonication until the solution is uniformly mixed, then evacuate the reaction system and fill it with nitrogen to completely remove the air, and then react in a vacuum at 80-150° C. for 1-5 days. After the reaction is completed, filter the reaction, and wash the resulting precipitate with methanol, tetrahydrofuran, and dichloromethane, respectively. Finally, dry the product in a vacuum at 40-120° C. for 12-24 h to obtain a photocatalyst donor-π-acceptor type conjugated organic polymer.

4. The method for preparing a photocatalyst for regenerating coenzyme NADH according to claim 3, characterized in that: The vacuum reaction condition of step c is a vacuum degree of 0.2-0.4 MPa.

5. The method for preparing a photocatalyst for regenerating coenzyme NADH according to claim 3, characterized in that: The mass concentration of potassium hydroxide in the potassium hydroxide-n-butanol solution is 0.05 g / mL.

6. The method for preparing a photocatalyst for regenerating coenzyme NADH according to claim 3, characterized in that: The volume ratio of the potassium hydroxide-n-butanol solution used in the preparation method to the n-butanol and o-dichlorobenzene in the mixed solvent is 1:(3-4):(1-2).

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