Heterogeneous conductive film catalyst for photocatalytic coenzyme regeneration and preparation method thereof

Abstract

The present invention discloses a heterogeneous conductive membrane catalyst for photocatalytic coenzyme regeneration. An organic polymer coating is grown on a silicon oxide surface by a hard template method, and then the template is removed to obtain a heterogeneous conductive membrane HCM based on a covalent organic polymer. During the growth of the covalent organic polymer coating, the amount of one aldehyde monomer is fixed unchanged, and different HCMs with microcapsule structures are obtained by regulating the ratio of the other two amino monomers. The contents of the two amino monomers m-Bpy and m-PaHSO3 used in the coating formation process will affect the electron and proton transfer problems of the photocatalyst during the photocatalytic process. Photocatalytic coenzyme regeneration involves the transfer and utilization of two electrons and one proton. By coordinating the contents of m-Bpy and m-PaHSO3 and then coordinating the electron and proton transfer behavior in the photocatalytic process, the optimal electron and proton transfer behavior is achieved under the optimal monomer ratio, and ultimately the photocatalytic coenzyme regeneration process is enhanced.

Description

Technical Field

[0001] The present invention relates to the preparation of photocatalysts, in particular to a high-efficiency catalyst for photocatalytic coenzyme regeneration and a preparation method thereof Background Art

[0002] Green biomanufacturing, a process centered on biotechnology, utilizes enzymes or microorganisms and chemical engineering techniques to produce target products. It represents a quintessential new type of productivity, potentially helping transform traditional industries and reducing industrial energy consumption by 15% and air and water pollution by approximately 30%. The vigorous development of green biomanufacturing technologies is crucial for addressing energy, resource, and environmental crises and achieving sustainable development. Industrial enzyme catalysis is a typical green biomanufacturing technology, of which redox enzyme catalysis accounts for approximately 25%, and most rely on nicotinamide coenzymes (such as NADH) to provide reducing power. However, the price of NADH per mole is approximately 5 million yuan, which to some extent limits the industrial application of enzyme-catalyzed processes. To this end, researchers have developed various coenzyme regeneration systems driven by chemical energy, electrical energy, and light energy. Among these, photocatalytic coenzyme regeneration using clean, abundant, and renewable solar energy offers advantages such as a clean energy source, environmental friendliness, and a controllable process.

[0003] The light-driven coenzyme NADH regeneration process mainly uses organic molecules such as triethanolamine as electron donors and semiconductors as photocatalysts. Visible or ultraviolet light is used to irradiate the semiconductor to generate photogenerated electrons and holes. Triethanolamine captures the holes, and the photogenerated electrons are transferred to the reduction site for NAD + To NADH. + The photocatalytic conversion of NAD to NADH involves the transfer of two electrons and one proton. The faster electron-hole recombination causes the electrons to be quenched prematurely, making it difficult to ensure that more photogenerated electrons are transferred to the reduction active site, thus reducing the electron utilization efficiency of the NADH regeneration process. At the same time, the proton transfer process directly affects the NAD + The efficiency of binding to protons affects the 1,4-NADH selectivity and initial reaction rate during the regeneration process.

[0004] Therefore, the variable monomer ratio in HCM preparation was used to regulate the electron and proton transfer behavior in the photocatalytic process. At the optimal ratio of m-Bpy and m-PaHSO3, the electron and proton transfer processes in photocatalysis were matched, achieving efficient and stable regeneration of the coenzyme NADH. Summary of the Invention

[0005] The purpose of the present invention is to provide a catalyst for photocatalytic coenzyme regeneration and a preparation method thereof. The raw materials for the preparation of the present invention are cheap and readily available, and the preparation process is simple and easy.

[0006] The present invention proposes a method for preparing a heterogeneous conductive film photocatalyst for photocatalytic coenzyme regeneration, comprising the following steps:

[0007] Step 1: Prepare silica particles modified with polyethyleneimine and dopamine: Mix silica balls with a polyethyleneimine aqueous solution and a dopamine aqueous solution to obtain liquid A, wherein the mass-to-volume ratio of the silica balls in liquid A is 1 g / 100 mL, and the mass ratio of the silica balls, polyethyleneimine, and dopamine is 1:2:2. Under a magnetic stirrer, magnetically stir liquid A in a sealed and perforated state to obtain suspension A; centrifuge the suspension A, wash it with water, and dry it to obtain silica particles modified with polyethyleneimine and dopamine.

[0008] Step 2: preparing core-shell particles, comprising:

[0009] 2-1) At room temperature, using the particles obtained in step 1 as template particles, in a three-necked flask, 1 mol of 2,4,6-tris(4-formylphenyl)-1,3,5-triazine monomer (m-TFPT) and tetrahydrofuran (THF) were mixed per 500 mg of the template particles to obtain liquid B, wherein the molar concentration of 2,4,6-tris(4-formylphenyl)-1,3,5-triazine monomer and tetrahydrofuran in liquid B was 1 mol / 110 mL; 6 mol / L acetic acid solution was added to solution B at a volume ratio of 1:110, and the mixture was hydrothermally refluxed under a magnetic stirrer to obtain liquid C;

[0010] 2-2) using tetrahydrofuran as a solvent, dissolving 2,4,6-tris(4-formylphenyl)-1,3,5-triazine monomer (m-TFPT), 5,5'-diamino-2,2'-bipyridine monomer (m-Bpy) and 2,5-diaminobenzenesulfonic acid monomer (m-PaHSO3) in an appropriate amount of tetrahydrofuran at a molar ratio of N1:N2:N3=2:(1-3):(0-2), and N1+N2+N3=5, to obtain liquid D;

[0011] 2-3) Liquid D was added to Liquid C at a volume ratio of 4:11 at a rate of 1 / 10 of Liquid D per minute, and the mixture was hydrothermally refluxed to obtain a suspension B. The suspension B was centrifuged, washed with tetrahydrofuran, and dried to obtain core-shell particles.

[0012] Step 3: Prepare a heterogeneous conductive film photocatalyst: add the core-shell particles obtained in step 2 to a 6 mol / L ammonium bifluoride solution at a mass volume ratio of 7-10 mg / mL, stir thoroughly to obtain a suspension C, centrifuge the suspension C, wash it with water, and dry it to obtain microcapsule-structured particles, which are the heterogeneous conductive film photocatalyst.

[0013] Furthermore, the preparation method of the present invention, wherein:

[0014] In step 1, the diameter of the silica spheres is 300-500 nm; the stirring speed of the magnetic stirring is 600-800 r / min, and the stirring time is 4 h; the speed of the centrifugal water washing is 8000-10000 r / min, and the time is 4-5 min; the drying temperature is 40° C., and the time is 24 h.

[0015] In step 2-1), the process conditions of the hydrothermal reflux reaction under a magnetic stirrer are: a stirring speed of 120 r / min, a reaction time of 30 min, and a temperature of 50° C. for the hydrothermal reflux reaction.

[0016] In step 2-2), N1:N2:N3 is any one of 2:3:0, 2:1:2, and 2:2:1, preferably, N1:N2:N3 is 2:2:1.

[0017] In step 2-3), liquid D was added to liquid C, and the hydrothermal reflux time was 48 hours; the suspension B was washed with tetrahydrofuran by centrifugation 3 times at a speed of 8000-10000 r / min, each time for 5 minutes; the drying temperature was 70°C, and the drying time was 12 hours.

[0018] In step three, the stirring time is 24 hours; the suspension C is centrifuged and washed 3 times at a speed of 8000-10000 r / min, each time for 5 minutes, and the drying temperature after centrifugal washing is 70°C for 12 hours.

[0019] For the convenience of description, in the examples of the present invention, the ratio of the amino monomers used (m-Bpy and m-PaHSO3) is different, and the heterogeneous conductive film photocatalysts with microcapsule structure finally obtained are respectively recorded as:

[0020] The molar ratio of m-TFPT to m-Bpy to m-PaHSO3 is 2:3:0, and the resulting heterogeneous conductive film photocatalyst with microcapsule structure is referred to as HCM. BS30 .

[0021] The molar ratio of m-TFPT to m-Bpy to m-PaHSO3 is 2:2:1, and the resulting heterogeneous conductive film photocatalyst with microcapsule structure is referred to as HCM. BS21 .

[0022] The molar ratio of m-TFPT to m-Bpy to m-PaHSO3 is 2:1:2, and the resulting heterogeneous conductive film photocatalyst with microcapsule structure is referred to as HCM. BS12 .

[0023] Compared to existing technologies, the present invention proposes a method for preparing a heterogeneous conductive film photocatalyst for photocatalytic coenzyme regeneration. This method, for the first time, utilizes the ratio of monomers during catalyst synthesis to regulate electron and proton transfer in photocatalysis. This method effectively addresses the mismatch between electron and proton transfer rates during photocatalytic coenzyme regeneration, thereby improving photocatalytic coenzyme regeneration performance. The present invention's preparation conditions are mild and the process is simple. Compared to existing photocatalytic coenzyme regeneration technologies, the system photocatalyst prepared in this invention, which has different ratios of amino monomers (m-Bpy and m-PaHSO3), significantly improves coenzyme regeneration performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1a ) is the HCM prepared in Example 1 of the present invention BS30 TEM photos;

[0025] Figure 1b ) is the HCM prepared in Example 2 of the present invention BS21 TEM photos;

[0026] Figure 1c ) is the HCM prepared in Example 3 of the present invention BS12 TEM photos;

[0027] Figure 2 HCM prepared in Examples 1-3 of the present invention BS30 , HCM BS21 and HCM BS12 Time-resolved fluorescence spectra of

[0028] Figure 3 HCM prepared in Inventive Examples 1-3 BS30 , HCM BS21 and HCM BS12 Proton conductivity;

[0029] Figure 4 HCM prepared in Inventive Examples 1-3 BS30 , HCM BS21 and HCM BS12 NADH yield for photocatalytic coenzyme regeneration. DETAILED DESCRIPTION

[0030] The present invention proposes a heterogeneous conductive membrane photocatalyst for photocatalytic coenzyme regeneration. The design concept involves growing an organic polymer coating on a silicon oxide surface using a hard template method, then removing the template to obtain a covalent organic polymer-based microcapsule membrane photocatalyst HCM. During the growth of the covalent organic polymer coating, the amount of one aldehyde monomer (m-TFPT) is fixed. By adjusting the ratio of the other two amino monomers (m-Bpy and m-PaHSO3), and utilizing the adjustable monomer ratio during coating growth, a series of heterogeneous conductive membrane photocatalysts with microcapsule structures having different amino monomer ratios (m-Bpy and m-PaHSO3) are prepared. The content of the two amino monomers, m-Bpy and m-PaHSO3, used in the coating formation process affects the electron and proton transfer of the photocatalyst during the photocatalytic process. A higher amount of m-Bpy facilitates electron transfer, while a correspondingly lower amount of m-PaHSO3 hinders proton transfer. Photocatalytic coenzyme regeneration involves the transfer and utilization of two electrons and one proton. By coordinating the content of m-Bpy and m-PaHSO3, the effect of coordinating the electron and proton transfer in the photocatalytic process is achieved. The optimal monomer ratio has the optimal electron and proton transfer behavior, which is beneficial to NAD + The conversion to NADH ultimately achieves the enhancement of the photocatalytic coenzyme NADH regeneration process.

[0031] The technical solution of the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments. The described specific embodiments are only used to explain the present invention and are not intended to limit the present invention.

[0032] Example 1: HCM with microcapsule structure BS30 Preparation and HCM-based BS30 The photocatalytic coenzyme NADH regeneration system is constructed as follows:

[0033] Step 1: Preparation of polyethyleneimine and dopamine modified silica particles:

[0034] 1 g of silica spheres (300-500 nm in diameter) prepared at room temperature were mixed with a polyethyleneimine aqueous solution and a dopamine aqueous solution in a mass ratio of approximately 1:1 under a magnetic stirrer at a stirring speed of 800 r / min. The mixed solution was stirred at a stirring speed of 800 r / min for 4 hours in a sealed and perforated state. The resulting suspension was centrifuged in a centrifuge (9000 r / min, 5 minutes), washed three times with water, and dried at 40°C for 24 hours to obtain modified template particles, referred to as SiPP.

[0035] Step 2: Preparation of core-shell particles:

[0036] At room temperature, a certain amount of modified template particles SiPP and 0.1 mol of m-TFPT were weighed and mixed with 11 mL of tetrahydrofuran solvent in a three-necked flask. 100 μL of 6 mol / L acetic acid solution was added. Under a magnetic stirrer, the stirring speed was 120 r / min, and the hydrothermal reflux reaction temperature was 50 ° C. After the reaction for 30 minutes, m-Bpy with a molar ratio of 3:2 to m-TFPT was dissolved in 4 mL of tetrahydrofuran solvent and added to the above three-necked flask at a rate of 1 / 10 per minute. After hydrothermal reflux for 48 hours, the resulting suspension was centrifuged in a centrifuge (speed 10000 r / min, time 5 minutes) and washed with tetrahydrofuran three times. It was dried at 70 ° C for 12 hours to obtain core-shell particles, referred to as SiPP@HCM. BS30 particles.

[0037] Step 3: Preparation of HCM microcapsule structure BS30 :

[0038] Weigh 80 mg of the above SiPP@HCM BS30 The particles were added to 8 mL of 6 mol / L ammonium bifluoride solution and stirred thoroughly for 24 h. The suspension was centrifuged (speed 10000 r / min, time 5 min) and washed with water three times. The suspension was then dried at 70 °C for 12 h to obtain microcapsule-structured HCM. BS30 particles.

[0039] The prepared photocatalyst HCM BS30 The electron lifetime was detected by time-resolved fluorescence spectroscopy and the proton conductivity was detected by electrochemical means, and then used in the coenzyme regeneration system. The process was carried out in phosphate buffer. The reaction solution contained triethanolamine as an electron donor, a rhodium complex as the reduction reaction active center, and HCM BS30 As a photocatalyst, NAD + As a substrate, 420nm LED lamp is used to provide light energy to achieve efficient photosynthesis of NADH.

[0040] Figure 1a ) is HCM BS30 TEM image shows that it is a microcapsule membrane structure with a thickness of 35 nm; Figure 2 The middle (shown in black) shows the HCM BS30 The electron lifetime is 374ps; Figure 3 HCM is shown BS30 The proton conductivity is 11.5 mS cm -1 ; Figure 4 The middle (shown in black) shows the HCM BS30 Used in the photocatalytic NADH regeneration process, the NADH yield was 83%.

[0041] Example 2: HCM with microcapsule structureBS21 Preparation and HCM-based BS21 The photocatalytic coenzyme NADH regeneration system was constructed, and the steps were basically the same as those in Example 1, except that in step 2, m-Bpy with a molar ratio of 3:2 to m-TFPT was replaced with m-Bpy with a molar ratio of 1:1 to m-TFPT and m-PaHSO3 with a molar ratio of 1:2 to m-TFPT, and finally a microcapsule structured HCM was prepared. BS21 particles.

[0042] Figure 1b ) is HCM BS21 TEM image shows that it is a microcapsule membrane structure with a thickness of 38 nm; Figure 2 The middle (shown in red) shows HCM BS21 The electron lifetime is 229ps; Figure 3 HCM is shown BS21 The proton conductivity is 63.4 mS cm -1 ; Figure 4 The middle (shown in red) shows HCM BS21 Used in the photocatalytic NADH regeneration process, the NADH yield is 90%.

[0043] Example 3: HCM with microcapsule structure BS12 Preparation and HCM-based BS12 The photocatalytic coenzyme NADH regeneration system was constructed, and the steps were basically the same as those in Example 1, except that in step 2, m-Bpy with a molar ratio of 3:2 to m-TFPT was replaced with m-Bpy with a molar ratio of 1:2 to m-TFPT and m-PaHSO3 with a molar ratio of 1:1 to m-TFPT, and finally a microcapsule structured HCM was prepared. BS12 particles.

[0044] Figure 1c ) is HCM BS12 TEM image shows that it is a microcapsule membrane structure with a thickness of 30 nm; Figure 2 The middle (shown in blue) shows HCM BS12 The electron lifetime is 145ps; Figure 3 HCM is shown in BS12 The proton conductivity is 170.8 mS cm -1 ; Figure 4 The middle (shown in blue) shows HCM BS12 Used in the photocatalytic NADH regeneration process, the NADH yield was 84%.

[0045] In summary, through the above examples and comparative examples and their corresponding TEM images, it is found that by changing the amino monomer during the synthesis process, a microcapsule membrane structure with adjustable thickness can be obtained. When the amount of aldehyde monomer is fixed and the ratio of the two aldehyde monomers is changed, the HCM synthesized has different electron and proton transfer behaviors. The higher the m-Bpy ratio, the more favorable the electron transfer. Therefore, from the time-resolved fluorescence spectrum, it can be seen that the HCM BS30 (374ps) showed a better performance than HCM BS21 (229ps) and HCM BS12 (145ps) longer electron lifetime, e.g. Figure 2 As shown; while HCM BS12 (170.8mS cm -1 ) showed a better performance than HCM BS21 (63.4mS cm -1 ) and HCM BS30 (11.5 mS cm -1 ) better proton conductivity, such as Figure 3 As shown. The photocatalytic coenzyme NADH regeneration process involves the participation of two electrons and one proton. The rapid electron-hole recombination quenches the electrons in advance, making it difficult for the available photogenerated electrons to be transferred to the reduction active site, thus reducing the electron utilization efficiency. At the same time, proton transfer affects the NAD + The efficiency of binding with protons seriously affects the selectivity and initial reaction rate of the generated 1,4-NADH. To obtain the optimal NADH regeneration efficiency, it is necessary to regulate the electron and proton transfer to match. Therefore, in the present invention, the ratio of monomers that affect electron and proton transfer is regulated, and the optimal electron and proton transfer rate is achieved when the ratio of amino monomers m-Bpy and m-PaHSO3 is 2:1, so that the NADH regeneration performance is effectively improved. Figure 4 shown.

[0046] Although the present invention has been described above in conjunction with the accompanying drawings, the present invention is not limited to the above-mentioned specific embodiments. The above-mentioned specific embodiments are merely illustrative and not restrictive. Under the guidance of the present invention, ordinary technicians in this field can make many improvements and changes without departing from the purpose of the present invention, which are all protected by the present invention.

Claims

1. A method for preparing a heterogeneous conductive film photocatalyst for photocatalytic coenzyme regeneration, characterized in that: The following steps are involved: Step 1: Preparation of polyethyleneimine and dopamine modified silica particles: Silica balls, a polyethyleneimine aqueous solution, and a dopamine aqueous solution were mixed to obtain liquid A, wherein the mass volume ratio of the silica balls in liquid A was 1 g / 100 mL, and the mass ratio of the silica balls, polyethyleneimine, and dopamine was 1:2:

2. Liquid A was magnetically stirred in a sealed and perforated state under a magnetic stirrer to obtain a suspension A; The suspension A was centrifuged and washed with water, and then dried to obtain silica particles modified with polyethyleneimine and dopamine; Step 2: preparing core-shell particles, comprising: 2-1) At room temperature, using the particles obtained in step 1 as template particles, in a three-necked flask, 1 mol of 2,4,6-tris(4-formylphenyl)-1,3,5-triazine monomer and tetrahydrofuran were mixed for every 500 mg of the template particles to obtain liquid B, wherein the molar concentration of 2,4,6-tris(4-formylphenyl)-1,3,5-triazine monomer and tetrahydrofuran in liquid B was 1 mol / 110 mL; 6 mol / L acetic acid solution was added to solution B at a volume ratio of 1:110, and the mixture was hydrothermally refluxed under a magnetic stirrer to obtain liquid C; 2-2) using tetrahydrofuran as a solvent, dissolving 2,4,6-tris(4-formylphenyl)-1,3,5-triazine monomer, 5,5'-diamino-2,2'-bipyridine monomer, and 2,5-diaminobenzenesulfonic acid monomer in an appropriate amount of tetrahydrofuran at a molar ratio of N1:N2:N3=2:(1-3):(0-2), with N1+N2+N3=5, to obtain liquid D; 2-3) adding liquid D to liquid C at a volume ratio of 4:11 at a rate of 1 / 10 of liquid D per minute, hydrothermally refluxed to obtain suspension B, centrifuged, washed with tetrahydrofuran, and dried to obtain core-shell particles; Step 3: Preparation of heterogeneous conductive film photocatalyst: The core-shell particles obtained in step 2 were added to a 6 mol / L ammonium bifluoride solution at a mass volume ratio of 7-10 mg / mL, and the suspension C was obtained after sufficient stirring. The suspension C was centrifuged and washed with water, and then dried to obtain microcapsule-structured particles, which are the heterogeneous conductive film photocatalyst.

2. The preparation method according to claim 1, characterized in that In step 2-2), N1:N2:N3 is any one of 2:3:0, 2:1:2, and 2:2:

1.

3. The preparation method according to claim 1, characterized in that In step 2-2), N1:N2:N3 is 2:2:

1.

4. The preparation method according to claim 1, characterized in that In step 1, the diameter of the silica spheres is 300-500 nm; the stirring speed of the magnetic stirring is 600-800 r / min, and the stirring time is 4 h; the speed of the centrifugal water washing is 8000-10000 r / min, and the time is 4-5 min; the drying temperature is 40° C., and the time is 24 h.

5. The preparation method according to claim 1, characterized in that In step 2-1), the process conditions of the hydrothermal reflux reaction under a magnetic stirrer are: a stirring speed of 120 r / min, a reaction time of 30 min, and a temperature of 50° C. for the hydrothermal reflux reaction.

6. The preparation method according to claim 1, characterized in that In step 2-3), liquid D was added to liquid C, and the hydrothermal reflux time was 48 hours; the suspension B was centrifuged and washed with tetrahydrofuran three times at a speed of 8000-10000 r / min, each time for 5 minutes; the drying temperature was 70°C, and the drying time was 12 hours.

7. The preparation method according to claim 1, characterized in that In step three, the stirring time is 24 hours; the suspension C is centrifuged and washed 3 times at a speed of 8000-10000 r / min, each time for 5 minutes, and the drying temperature after centrifugal washing is 70°C for 12 hours.

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