A high-efficiency composite photocatalytic material based on MOF loaded CdS and a preparation method and application thereof

Abstract

This method discloses a high-efficiency composite photocatalytic material based on MOF-supported CdS in the field of photocatalyst materials. The composite material uses MOF as a support, and CdS is grown on the MOF via ion adsorption to form supported CdS quantum dots. The porous material constructed from MOF, with its numerous adsorption sites, large specific surface area, and excellent conductivity, allows for more stable adsorption and fixation of CdS, promoting electron transfer and utilization. This effectively improves the separation rate of photogenerated electron-hole pairs and the recycling rate of the composite material. When applied to photocatalytic regeneration of NADH, a 77% yield can be achieved in 6 minutes, effectively shortening the reaction time and improving yield performance. The material can be recycled more than 40 times. Furthermore, a green drug synthesis system for the reaction of (E)-4-chloro-1-phenyl-1-butene to (E)-1-chloro-4-phenyl-3-buten-2-ol, driven by a regenerated coenzyme-driven P450 enzyme, was successfully constructed for the first time.

Description

Technical Field

[0001] This invention belongs to the field of photocatalytic materials technology, and specifically relates to a high-efficiency composite photocatalytic material based on MOF-supported CdS, its preparation method and application. Background Technology

[0002] Enzyme catalysis boasts advantages such as high efficiency, specificity, and mildness. Enzymes are mainly classified into six categories, with oxidoreductases accounting for approximately 30% of all enzymes and being the most widely used. They exhibit high catalytic efficiency in reactions such as carbonyl reduction, carbon-hydrogen bond oxidation, and carbon-carbon double bond cyclization. For the production of pharmaceutical compounds, the enantioselectivity of oxidoreductases is crucial. For example, the P450 enzyme-catalyzed synthesis of (E)-1-chloro-1-phenyl-1-butene from (E)-1-chloro-4-phenyl-3-buten-2-ol typically requires a two-step reaction in a chemical catalytic system, involving specific temperatures and the use of hazardous chemical reagents.

[0003] Enzyme catalysis is a relatively green synthetic method. It is known that 80% of reactions involving oxidoreductases require NADH. NAD(H) usually exists in two forms: oxidized and reduced, namely NAD... + The term NADH is used to describe the process of catalysis. Most oxidoreductases require one or more nicotinamide adenine nucleotides (NADH) as cofactors. The regeneration of cofactors to drive oxidoreductase activation can also enable novel green drug synthesis reactions. However, a continuous supply of NADH is usually required during the reaction, leading to high application costs. Therefore, researching an economical, green, and sustainable NADH regeneration system is of great significance for the widespread industrial application of NADH.

[0004] Semiconductor cadmium sulfide (CdS) is a catalyst capable of photocatalytic regeneration of the coenzyme NADH. However, CdS photocatalysts have the following drawbacks: Its band gap is 2.4 eV, allowing it to be excited by light of a wider wavelength, effectively enhancing its absorption of natural light. However, prolonged exposure to light after photoexcitation causes photocorrosion of CdS, severely limiting its photocatalytic activity. Furthermore, CdS is prone to aggregation, reducing the contact area between the substrate and the photocatalyst, which is detrimental to improving photocatalytic activity. Therefore, its application in photocatalytic regeneration of NADH results in long reaction times and low yields; for example, the yield is only 50.4% after 60 minutes of reaction. Thus, there is significant room for improvement in the application of CdS in photocatalytic regeneration of NADH. Summary of the Invention

[0005] The present invention aims to provide a method for preparing a highly efficient composite photocatalytic material based on MOF-supported CdS, in order to solve the problem that the photocatalytic material CdS is prone to agglomeration during application in the prior art, which is not conducive to improving photocatalytic activity.

[0006] Firstly, this solution provides a method for preparing a highly efficient composite photocatalytic material based on MOF-supported CdS, comprising the following steps:

[0007] S1. Preparation of MOF porous materials;

[0008] S2. Using the aforementioned MOF porous material as a carrier, Cd-containing materials are placed... 2+ The solution is adsorbed onto the MOF structure;

[0009] S3, Add S 2+ The solution and Cd adsorbed on the MOF 2+ Combined with the generated CdS, the CdS is fixed on the MOF;

[0010] S4. After drying, a composite photocatalytic material with CdS supported on MOF is obtained, named CdS / MOF.

[0011] Further optimization, S2 incorporates Cd 2+ The solution and S3 were added to the solution containing S 2+ After preparing the solution, stir each solution for 2–5 hours.

[0012] The present invention has the following beneficial effects:

[0013] 1. The introduction of MOF in this invention effectively improves the particle size of CdS and inhibits the aggregation of CdS.

[0014] The CdS / MOF composite material contains characteristic diffraction peaks of both MOF and CdS. Comparing the composite CdS / MOF with single-phase CdS, the characteristic diffraction peaks of CdS are broadened in the CdS / MOF composite, the particle size of CdS is significantly reduced, and the CdS particles are well dispersed on the MOF surface. This indicates that the introduction of MOF can effectively improve the particle size of CdS, effectively suppress CdS aggregation, and also enhance the interaction between CdS and MOF.

[0015] 2. The suppression of CdS aggregation helps to increase the contact area between the substrate and the photocatalyst, which is beneficial to the improvement of photocatalytic activity.

[0016] 3. The obtained CdS / MOF was used for photocatalytic regeneration of coenzyme NADH, with rapid and high yield.

[0017] The inventors tested the photocatalytic regeneration performance of MOF, CdS, and CdS / MO for coenzyme regeneration. The results showed that the pure MOF structure had no photocatalytic performance; CdS yielded only 50.4% after 60 minutes; while CdS / MOF performed exceptionally well, achieving a 67.2% yield of NADH coenzyme regeneration within just 8 minutes. Compared to CdS, the time was significantly shortened and the yield was significantly improved, resulting in a significant enhancement of the economic efficiency, greenness, and sustainability of the NADH regeneration system.

[0018] 4. The following two aspects illustrate that the method of the present invention is beneficial to the formation of the composite material.

[0019] (1) CdS / MOF composite material at 1179 cm⁻¹ -1 The absorption peak of CdS is relatively weaker than that of MOF because the interaction between CdS crystal and MOF forms a new stretching vibration absorption peak of thioether group (SC), which is beneficial to the formation of the CdS / MOF composite material.

[0020] (2) The binding energies of Cd and S elements in CdS / MOF both shift to the lower energy region. This phenomenon indicates that during the formation of CdS / MOF, charge transfer occurs at the interface between CdS and MOF, and electrons move from CdS to ZnO, resulting in a tight connection between MOF and CdS, which is beneficial to the formation of composite materials.

[0021] 5. There is an interaction force between MOF and CdS, which allows them to be tightly connected.

[0022] The inventors characterized the morphology and structure of CdS, MOF, and CdS / MOF using SEM. The results showed that CdS was a blocky material composed of very small spherical particles, and that single-phase CdS was prone to agglomeration, forming larger aggregates of CdS. MOF, on the other hand, exhibited a larger, more regular crystal morphology, with particle sizes ranging from 1.1 to 1.3 μm, and no nanoparticle agglomeration was observed; the MOF surface was relatively smooth. The CdS-loaded composite material showed significantly more particulate matter on its surface compared to pure MOF, indicating a CdS embedding effect on the MOF. Furthermore, the elemental distribution diagram revealed a uniform distribution of elements on the CdS / MOF surface, suggesting an interaction force between MOF and CdS, resulting in a tight bond between them.

[0023] Furthermore, the preparation of the MOF porous material described in S1 is as follows: zinc salt solution is added to an imidazole aqueous solution, and the reaction is carried out to obtain the MOF porous material.

[0024] Further, in S1, after adding zinc salt solution to imidazole aqueous solution and reacting, papain is added for modification, followed by S2 to S4 processes to prepare a composite photocatalytic material with an external coating layer, named CdS / MOF-P.

[0025] The CdS / MOF-P further prepared in this invention possesses stable recycling and reusability. The prepared CdS / MOF-P was used for photocatalytic regeneration of NADH, achieving a yield of 66.5% in 10 minutes. After 28 cycles, the catalytic activity of CdS / MOF-P remained essentially unchanged, demonstrating significantly improved recyclability compared to CdS / MOF. This indicates that the addition of papain modification enhances the cycling stability of the photocatalytic composite material.

[0026] Furthermore, in step S1, after the papain reaction, ethyl orthosilicate solution is added for mixing and modification. Then, through steps S2 to S4, the final composite photocatalytic material is prepared and named CdS / MOF-P / SiO2.

[0027] The CdS / MOF-P / SiO2 material further prepared in this invention exhibits improved photogenerated electron-hole properties, indicating that the photosensitivity of the material is significantly enhanced after modification with tetraethyl orthosilicate. When the CdS / MOF-P / SiO2 is used for photocatalytic regeneration of coenzyme NADH, the photocatalytic efficiency is further improved, achieving a higher yield of 72.6% within 6 minutes. This effectively shortens the reaction time and improves the yield performance, while significantly increasing the recyclability of the composite material. The photocatalytic composite material CdS / MOF-P / SiO2 was tested for 34 cycles of NADH regeneration.

[0028] Furthermore, the imidazole aqueous solution is a 2-methylimidazolium solution, and the zinc salt solution is a ZnAc solution; the volume concentration of the orthosilicate solution is 5% to 10%.

[0029] Furthermore, the Cd 2+ Solution and S 2+ The amount of solution added was the same, and the molar concentration was 1–30 mmol.

[0030] The Cd-containing 2+ The solution includes one of CdSO4, CdCl2, or (CH3COO)2Cd·2H2O solution, S 2+ The solution includes one of Na2S, CH4N2S, or C2H5NS solutions.

[0031] Furthermore, in step S1, the reaction temperature is 5℃~30℃, and in step S4, the drying temperature is 40℃~80℃.

[0032] Secondly, the present invention also provides CdS / MOF, CdS / MOF-P and CdS / MOF-P / SiO2 composite materials with high photocatalytic properties and recyclability prepared by the above methods.

[0033] The MOF porous material described in this invention has the characteristics of multiple surface adsorption sites, large specific surface area, and good conductivity. It can more stably adsorb and fix CdS, promoting electron transfer and utilization. By using such MOF porous material to load CdS to obtain any one of CdS / MOF, CdS / MOF-P, and CdS / MOF-P / SiO2, the separation rate of photogenerated electron-hole pairs and the recycling rate of composite photocatalytic materials can be effectively improved.

[0034] Thirdly, any one of the CdS / MOF, CdS / MOF-P, and CdS / MOF-P / SiO2 described in this invention, when applied to photocatalytic regeneration of NADH, can significantly improve yield performance in a short period of time.

[0035] The inventors tested the band gap values ​​of CdS, CdS / MOF-P, and CdS / MOF-P / SiO2, finding them to be 2.24 eV, 3.0 eV, and 2.98 eV, respectively. Compared to CdS, the composite photocatalysts CdS / MOF-P and CdS / MOF-P / SiO2 exhibit larger band gap values, indicating that they can absorb higher-energy light. Under the same light intensity conditions, photocatalysts with larger band gap values ​​have more opportunities to absorb higher-energy light, thereby exciting more electron-hole pairs to promote the photocatalytic reaction. Furthermore, the large band gap values ​​of the composite photocatalysts CdS / MOF-P and CdS / MOF-P / SiO2 in this invention can reduce the recombination and loss of photoelectrons outside the illuminated area, improving the efficiency of the photocatalyst. These characteristics are reflected in the performance and rate of photocatalytic regeneration of NADH.

[0036] Specifically, the application of the high-efficiency composite photocatalytic material based on MOF-supported CdS in the photocatalytic regeneration of NADH includes the following steps:

[0037] (1) The composite photocatalytic material is combined with coenzyme NAD + An electron donor and an Rh complex were placed in a quartz test tube, and PB buffer was added to obtain mixture A.

[0038] (2) Place mixture A in a photoreactor and stir in the dark for 10 min. Use 1.5A, 420nm blue light as the light source and react at a temperature of 15℃~30℃ to obtain NADH.

[0039] Furthermore, the amount of the electron donor is 5 w / v% to 30 w / v%, preferably 5 w / v%; the electron donor is selected from triethanolamine, sodium ethylenediaminetetraacetate, ascorbic acid, or methanol, and the Rh complex is [Cp*Rh(bpy)(H2O)]. 2+ The concentration is 0.1–0.5 mM, and the concentration of the PB buffer is 0.1 M with a pH value of 5–9.

[0040] Fourthly, the application of the coenzyme NADH obtained by regeneration in this invention in constructing a green drug synthesis system in which the regenerated coenzyme-driven P450 enzyme catalyzes the reaction of (E)-4-chloro-1-phenyl-1-butene to produce (E)-1-chloro-4-phenyl-3-buten-2-ol.

[0041] The regenerated coenzyme NADH obtained in this invention was used for the first time to drive the P450 enzyme-catalyzed reaction to generate (E)-1-chloro-4-phenyl-3-buten-2-ol. As the concentration of regenerated NADH gradually increased, the yield of the product showed an increasing trend, thus indicating that the regenerated coenzyme NADH has good biological activity. Attached Figure Description

[0042] Figure 1 XRD patterns of pure CdS, MOF, composite photocatalysts MOF-P, CdS / MOF, CdS / MOF-P, and CdS / MOF-P / SiO2.

[0043] Figure 2 , Figure 3 The images show the HRTEM image and EDS mapping analysis of the CdS / MOF composite material, respectively.

[0044] Figure 4 , Figure 5 The images show the HRTEM image and EDS mapping analysis of the CdS / MOF-P composite material, respectively.

[0045] Figure 6 , Figure 7 The images show the HRTEM image and EDS mapping analysis of the CdS / MOF-P / SiO2 composite material, respectively.

[0046] Figure 8 To investigate the cycling stability of composite photocatalytic materials; (a) CdS / MOF; (b) CdS / MOF-P; (c-d) Cycle counts of CdS / MOF-P photocatalytic materials with different CdS loadings;

[0047] Figure 9 FTIR spectra of CdS, MOF-P, CdS / MOF-P and CdS / MOF-P / SiO2 composites;

[0048] Figure 10 Images (a) through (f) are SEM images of CdS, MOF, CdS / MOF, MOF-P, CdS / MOF-P, and CdS / MOF-P / SiO2, respectively (the inserted images were taken at a higher magnification).

[0049] Figure 11 (a) XPS full spectrum of CdS, MOF and CdS / MOF; (b) Zn 2p, (c) Cd 3d, (d) S2p, (e) C1s, (f) O 1s high-resolution narrow spectrum;

[0050] Figure 12 XPS images of CdS, MOF-P, CdS / MOF-P, and CdS / MOF-P / SiO2; (a) full spectrum of MOF-P and CdS / MOF-P; (b) full spectrum of CdS / MOF-P / SiO2; (c) high-resolution narrow spectrum of Zn 2p, (d) O 1s, (e) Cd 3d, and (f) S2p.

[0051] Figure 13 EPR images of pure CdS, CdS / MOF-P, and CdS / MOF-P / SiO2;

[0052] Figure 14 The UV-Vis diffuse reflectance spectra (UV-VIS-NIR) and tauc plots of pure CdS, CdS / MOF-P, and CdS / MOF-P / SiO2 are shown.

[0053] Figure 15 Performance graphs for different conditions of CdS / MOF-P / SiO2 photocatalytic regeneration of NADH: (a) Screening of CdS / MOF-P / SiO2 composite photocatalyst dosage; (b) Screening of different pH values ​​of PB buffer reaction solution; (c) Screening of electron donor types; (d) Optimization of triethanolamine (TEOA) dosage; (e) Optimization of Rh complex concentration in the reaction; (f) Spectral scanning.

[0054] Figure 16 High performance liquid chromatogram and standard curve of (E)-1-chloro-4-phenyl-3-buten-2-ol. Detailed Implementation

[0055] The following detailed description illustrates the specific implementation method:

[0056] Unless otherwise specified, the reagents, methods and equipment used in this invention are all conventional reagents, methods and equipment in this technical field.

[0057] Example 1: A method for preparing CdS / MOF composite photocatalytic materials, the method comprising the following steps:

[0058] (1) Take a clean 500ml beaker, mix 2-methylimidazole solution (0.8M, 200ml) with ZnAc solution (0.5M, 20ml) and stir for 3 hours until MOF is formed;

[0059] (2) Add CdSO4 solution (5 mmol, 20 ml ddH2O) and stir for 3 hours to allow the Cd in the solution to dissolve. 2+ Adsorbed on the MOF surface;

[0060] (3) Add Na2S solution (5 mmol, 20 ml ddH2O), stir for 3 hours, and let S... 2- Fully compatible with Cd on MOF structures 2+ Adsorption-binding growth;

[0061] (4) Vacuum drying at 60℃, followed by drying and grinding to obtain CdS / MOF.

[0062] By replacing CdSO4 with CdCl2 solution or (CH3COO)2Cd·2H2O in Example 1, and replacing Na2S solution with CH4N2S solution or C2H5NS solution, while keeping other components and steps unchanged, CdS / MOF composite photocatalytic materials can also be prepared.

[0063] Figure 1 The XRD pattern of the CdS / MOF composite material prepared in Example 1 shows that CdS exhibits diffraction peaks at 2θ = 26.5°, 44.0°, and 52.1°, respectively, which correspond to the (111), (220), and (311) crystal planes in the diffraction pattern (PDF#02-0454) of the CdS cadmium sulfide crystal structure. By comparison... Figure 1 Two spectral lines were observed for the MOF and the simulated MOF. The diffraction peaks of the sample MOF corresponded to the standard card PDF#00-062-1030. The CdS / MOF composite material contained both characteristic diffraction peaks of MOF and CdS. Comparing the composite CdS / MOF with single-phase CdS, it was found that the characteristic diffraction peaks of CdS in the composite were broadened, indicating that the particle size of CdS was reduced.

[0064] Figure 2 and Figure 3 HRTEM and EDS mapping of the CdS / MOF composite material prepared in Example 1 clearly show the microstructure and chemical composition of the CdS / MOF composite material, such as... Figure 2As shown, the MOF surface is bonded with embedded CdS particles, with a lattice spacing of 0.21 nm corresponding to the (220) crystal plane of CdS in the XRD pattern; the crystal diffraction analysis results correspond to the (200), (311), and (222) crystal planes of CdS, confirming that the material is a composite material composed of MOF-supported CdS nanoparticles. The EDS diagram ( Figure 3 It was observed that the C, Zn, N, and O elements on the surface of the CdS / MOF and CdS / MOF-P composites originated from MOF, while the Cd and S elements originated from CdS. This is consistent with the XRD analysis results showing the simultaneous presence of MOF and CdS phases in the composites. The elemental distribution diagrams indicate that the elements are relatively uniform, suggesting that there may be interaction forces between MOF and CdS, resulting in a tight bond between them.

[0065] We characterized the morphology and structure of CdS, MOF, and CdS / MOF using SEM. It is clear that CdS is a blocky material composed of very small spherical particles. Figure 10 a) Single-phase CdS tends to aggregate, forming large, aggregated CdS masses. MOFs, on the other hand, exhibit larger, more regular crystal morphologies; the particle size of MOFs is between 1.1 and 1.3 μm. Figure 10 (b) No nanoparticle aggregation was observed, and the MOF surface was relatively smooth. The CdS-loaded composite material showed significantly more particulate matter compared to the pure MOF surface, indicating CdS embedding within the MOF. However, the CdS particle size was significantly reduced in the CdS / MOF composite, and the CdS particles were well dispersed on the MOF surface, a result consistent with XRD characterization. This demonstrates that the introduction of MOF effectively improves the CdS particle size, effectively suppresses CdS aggregation, and enhances the interaction between CdS and MOF.

[0066] Figure 9 FTIR plots of CdS, MOF, and CdS / MOF, as shown below. Figure 9 As shown, CdS at 3450 cm⁻¹ -1 With 1630cm -1 The absorption peak at 3450 cm⁻¹ indicates that it represents H₂O in CdS, with a broad absorption band. -1 It is the stretching vibration peak of -OH, 1630 cm⁻¹ -1 The nearby peak is the bending vibration peak of HOH. 1572 cm⁻¹ in MOF-P -1 It shows tensile vibrations at C=N, 1230-1460 cm. -1 The peaks within this range represent the stretching vibration of CN, indicating the presence of the organic ligand imidazole. (1658 cm⁻¹) -1The C=O stretching vibration is the carbonyl bond of the enzyme in the MOF produced by papain, 1179 cm⁻¹ -1 The absorption peak is usually attributed to the CH vibration of the organic ligand, 1460 cm⁻¹ -1 With 1428cm -1 The absorption peak at 437 cm⁻¹ is caused by the symmetric stretching vibration of the CH bond. -1 The region is attributed to the Zn-O vibration; the infrared spectrum of the CdS / MOF composite material is similar to that of the MOF, but it also includes the 1387 cm⁻¹ region from the CdS spectrum. -1 1110cm -1 620cm -1 Multiple characteristic absorption peaks were observed in the CdS / MOF composite material at 1179 cm⁻¹. -1 The absorption peak of CdS is relatively weaker than that of MOF. The reason is that the interaction between CdS crystal and MOF forms a new stretching vibration absorption peak of thioether group (SC), which is conducive to the formation of the composite material.

[0067] The CdS / MOF composite photocatalyst material prepared in Example 1 was analyzed by photoelectron spectroscopy (XPS), as shown... Figure 11 As shown, this material mainly contains six elements: C, Zn, O, N, Cd, and S. Among them, C, Zn, O, and N elements originate from the MOF phase, while Cd and S elements originate from the CdS phase. This analytical result is consistent with the results obtained from EDS characterization. Figure 11 It can be seen that the C peak at 284.8 eV is used for XPS data calibration. Figure 11 As shown in Figure b, the Zn 2p spectrum shows two strong peaks at 1021.1 eV and 1044.1 eV for Zn 2p3 / 2 and Zn 2p1 / 2, respectively, corresponding to the Zn present in the MOF support. 2+ Zn in CdS / MOF 2+ The binding energy position shifts were 1023.8 eV and 1046 eV, respectively, indicating an increase in binding energy. This was observed through the O1s spectrum (…). Figure 11 f) Analysis showed that the peak at 531.1 eV was attributed to a Zn-O bond, indicating the presence of ZnO in the photocatalytic material. In pure CdS, Cd 3d( Figure 11 c) and S2p peak ( Figure 11d) The binding energies are 412.1 eV, 405.1 eV, and 162.1 eV, respectively. The binding energies corresponding to the Cd 3d and S 2p peaks in CdS / MOF are 411.2 eV, 404.4 eV, and 161.1 eV, indicating the presence of Cd-S bonds. The binding energies of Cd and S elements in CdS / MOF shift to lower energy regions, which is exactly the opposite of the change in Zn 2p. This phenomenon indicates that during the formation of CdS / MOF, charge transfer occurs at the CdS-MOF interface, with electrons moving from CdS to ZnO, resulting in a tighter bond between MOF and CdS, which is beneficial for the formation of the composite material.

[0068] The composite material CdS / MOF prepared in Example 1 above is used as a photocatalyst in the regeneration of coenzyme NADH. The application includes the following steps: 1 mM NAD + 20 mg of photocatalyst, 10 w / v % TEOA, 0.25 mM [Cp*Rh(bpy)(H2O)]2, and PB buffer (pH 8.0, 0.1 M) solution were added to 10 ml and placed in a quartz tube. The tube was then placed in a photoreactor and stirred in the dark at 25 °C and 40 rpm for 10 min until the mixture reached adsorption-desorption equilibrium. The light source was then turned on at 420 nm and 1.5 A to carry out the reaction. The reaction process is as follows, and the absorbance was measured. The cyclic stability test procedure of the photocatalyst was performed. The photocatalyst in the regenerated reaction system was centrifuged for reuse. The performance test results are shown in Table 1 below.

[0069]

[0070] Table 1 Performance test of CdS / MOF photocatalytic regeneration of coenzyme NADH

[0071]

[0072] The pure MOF structure has no photocatalytic performance (Table 1, Entry 1); CdS (theoretical CdS loading of the composite material is 2.4 mg), has a yield of 50.4% after 60 min and can only be recycled 9 times (Table 1, Entry 2); CdS / MOF, has a yield of 67.2% after 8 min (Table 1, Entry 3), and completely loses its photocatalytic activity after 4 recycling cycles. Figure 8 a) The next step is to improve the cyclic stability of the composite material through regulation and modification.

[0073] Example 2: Preparation of the composite photocatalytic material CdS / MOF-P.

[0074] Following the steps in Example 1 for preparing CdS / MOF composite materials, papain was added in step (1) to obtain CdS / MOF-P. Specifically, step (1) involved taking a clean 500ml beaker, mixing 2-methylimidazole solution (0.8M, 200ml) and ZnAc solution (0.5M, 20ml), then adding 1-5g of papain, preferably 5g, and stirring for 3 hours until the MOF was formed.

[0075] The CdS / MOF-P composite material prepared in Example 2 was used for photocatalytic regeneration of coenzyme NADH. The photocatalytic regeneration reaction system for coenzyme NADH was the same as in Example 1. The cycle stability test of the photocatalyst is shown in Table 2. The photocatalyst in the regeneration reaction system was recovered by centrifugation and reused.

[0076] Table 2. Performance of CdS / MOF-P photocatalytic regeneration of coenzyme NADH

[0077]

[0078] In Example 2, CdS / MOF-P was prepared and used for photocatalytic regeneration of the coenzyme NADH, with a yield of 66.5% after 10 min (Table 2, Entry 2); cyclic stability was tested as follows. Figure 8 As shown in b, after 28 cycles, the catalytic activity of the photocatalytic material remained basically unchanged, indicating that the cycle stability of the photocatalytic composite material was enhanced after the addition of papain modification.

[0079] Example 2 prepared CdS / MOF-P, which was then analyzed by XRD ( Figure 1 Analysis of the crystal structure of the material showed that the addition of papain modification did not change the crystal structure of the composite material; HRTEM and EDS mapping were used to further analyze the crystal structure. Figure 4 and Figure 5 The microstructure of the CdS / MOF-P composite material prepared by adding papain in Example 2 was unchanged, indicating that the CdS loaded with MOF was composed of MOF. The Cd and S elements were evenly distributed. Its morphology was characterized by SEM. Figure 10 (d~e) After modification with papain, the surface of the material exhibits a wrinkled coating layer. This coating layer significantly enhances the stability of CdS / MOF, effectively encapsulating the CdS nano-quantum dots on the material surface and preventing them from detaching during use. FTIR (…) Figure 9 The skeletal functional group structure of the material was analyzed, and the addition of papain did not change the internal structure of the material. The addition of papain effectively enhanced the cycling stability of the material.

[0080] Furthermore, the CdS loading of the CdS / MOF-P material was optimized to improve its photocatalytic performance. Specifically, based on Example 2, different amounts of CdSO4 solution and Na2S solution (2.5, 5, 10, 15, 20, 25, 30 mmol) were added during the preparation process (the amounts of CdSO4 solution and Na2S solution added were the same), ultimately preparing CdS / MOF-P composite materials with different CdS loadings, labeled as 2.5-CdS / MOF-P, 5-CdS / MOF-P, 10-CdS / MOF-P, 15-CdS / MOF-P, 20-CdS / MOF-P, 25-CdS / MOF-P, and 30-CdS / MOF-P. The prepared CdS / MOF-P composite materials were then subjected to photocatalytic regeneration of coenzyme NADH. The photocatalytic regeneration reaction system for coenzyme NADH was referenced in Example 1. The results of the cycle stability test of the photocatalyst are shown in Table 3.

[0081] Table 3. Performance of CdS / MOF-P photocatalytic regeneration of coenzyme NADH with different CdS loadings.

[0082]

[0083] In Table 3, the 5-CdS / MOF-P yield was 66.5%, exhibiting the highest performance; the cyclic stability of the material was tested as follows: Figure 8 (c~d) 2.5-CdS / MOF-P can be recycled 21 times, 5-CdS / MOF-P remains basically unchanged after 28 recycling cycles, 10-CdS / MOF-P can be recycled 42 times, and 20-CdS / MOF-P can be recycled more than 36 times. Optimizing the CdS loading did not improve the catalytic performance, but it did improve the cycle stability. Based on the issue of improving catalytic efficiency, further regulation and modification were carried out on the 5-CdS / MOF-P composite material.

[0084] Example 3: A method for preparing a CdS / MOF-P / SiO2 photocatalyst, the method comprising the following steps:

[0085] (1) Take a clean 500ml beaker, mix 2-methylimidazole solution (0.8M, 200ml) with ZnAc solution (0.5M, 20ml) and 5g papain, stir for 3 hours until MOF is formed;

[0086] (2) Add 10 ml of ethyl orthosilicate and stir for 3 hours;

[0087] (3) Add CdSO4 solution (5 mmol, 20 ml ddH2O) and stir for 3 hours to allow the Cd in the solution to dissolve. 2+ Adsorbed on the MOF surface;

[0088] (4) Add Na2S solution (5 mmol, 20 ml ddH2O), stir for 3 hours, and let S... 2- Fully compatible with Cd on MOF structures 2+ Adsorption-binding growth;

[0089] (5) Vacuum drying at 60℃, followed by drying and grinding to obtain CdS / MOF-P / SiO2.

[0090] The performance of the CdS / MOF-P / SiO2 photocatalytic regeneration of coenzyme NADH prepared in Example 3 is shown in Table 4. The reaction was carried out based on the photocatalytic regeneration of NADH in Example 1.

[0091] Table 4. Performance of CdS / MOF-P / SiO2 photocatalytic regeneration of coenzyme NADH

[0092]

[0093] The data in Table 4 show that the photocatalyst, when reacted with the composite material CdS / MOF-P / SiO2, achieved a NADH regeneration rate of 72.6% after 6 minutes, further improving the photocatalytic efficiency.

[0094] Example 4: The CdS / MOF-P / SiO2 composite material for photocatalytic regeneration of coenzyme NADH in Example 3 was subjected to cycle stability testing. Under the conditions of Example 3, the scaled-up reaction system was 20 mL, and 100 mg of photocatalyst was used. Other concentrations and conditions remained unchanged, and cycle stability testing was conducted.

[0095] Table 5. Cyclic stability test of CdS / MOF-P / SiO2 photocatalytic regeneration of coenzyme NADH.

[0096]

[0097] Table 5 (Continued) shows the cycling stability test of CdS / MOF-P / SiO2 photocatalytic regeneration of coenzyme NADH.

[0098]

[0099] The data in Table 5 show that the photocatalytic composite material CdS / MOF-P / SiO2 can be recycled 34 times in the recycling test of the regenerated coenzyme NADH. However, the overall catalytic activity decreases due to the loss of materials during the recycling process.

[0100] CdS / MOF-P / SiO2 was subjected to XRD ( Figure 1Analysis of the crystal structure of the material showed that the addition of ethyl silicate did not change the crystal structure of the composite material; HRTEM and EDS mapping were used to analyze the crystal structure. Figure 4 and Figure 5 Analysis of Example 8 showed that the microstructure of the CdS / MOF-P / SiO2 composite material prepared by adding papain was unchanged, indicating that the Cd and S elements were uniformly distributed. FTIR analysis revealed that the microstructure of the composite material was composed of MOF-supported CdS. Figure 9 The framework functional group structure of the material was analyzed. The modification did not change the internal structure of the material. Silicon-oxygen bond functional groups were added to the material prepared in Example 1. The structure was analyzed using XPS. Figure 12 The binding energy shift of the composite material was analyzed. The change in binding energy after modification was consistent with that of CdS / MOF, indicating that the interaction between the materials remained unchanged. Its morphology and structure were characterized by SEM, such as... Figure 10 (f) After modification, the material becomes an irregular polyhedron. Analysis shows that the addition of tetraethyl orthosilicate forms some silicon-oxygen bonds, leading to irregular crystal formation. The photogenerated electronic properties of the material are then analyzed using EPR testing, such as... Figure 13 As shown, under the same test conditions, CdS / MOF-P / SiO2 exhibits the best photogenerated electron-hole performance, indicating that the photosensitivity of the material is significantly improved after the addition of tetraethyl orthosilicate, thus resulting in a significant improvement in photocatalytic efficiency.

[0101] Figure 14 The UV-Vis diffuse reflectance spectra (UV-VIS-NIR) and tauc plots of pure CdS, CdS / MOF-P, and CdS / MOF-P / SiO2 are shown below. Figure 14 As shown in Figure a, the absorption band edges of CdS, CdS / MOF-P, and CdS / MOF-P / SiO2 are located at 592, 435, and 438 nm, respectively. The absorption edges of the composite materials CdS / MOF-P (435 nm) and CdS / MOF-P / SiO2 (438 nm) are lower than those of CdS (592 nm), indicating that the composite materials can absorb a wider spectral range than pure CdS. The TAUC diagram obtained based on the absorption spectrum analysis is shown below. Figure 14As shown in b, the band gap values ​​of CdS, CdS / MOF-P, and CdS / MOF-P / SiO2 are 2.24 eV, 3.0 eV, and 2.98 eV, respectively, which is consistent with the results of UV-Vis diffuse reflectance spectroscopy. The larger band gap value of the composite photocatalyst indicates that it can absorb higher energy light. Under the same light intensity conditions, the photocatalyst with a larger band gap value has more opportunities to absorb higher energy light, thereby exciting more electron-hole pairs to promote the photocatalytic reaction. At the same time, the material with a larger band gap value can also reduce the recombination and loss of photoelectrons outside the illumination area, and improve the efficiency of the photocatalyst. These characteristics can be reflected in the performance and rate of photocatalytic regeneration of NADH.

[0102] The CdS / MOF-P / SiO2 regeneration NADH reaction system was optimized, starting with screening the dosage of photocatalyst material (10mg, 20mg, 30mg, 40mg, 50mg). Figure 15 a) The results showed that the yields of 10mg, 20mg, 30mg, 40mg, and 50mg were 63%, 70%, 69%, 71%, 71%, and 71%, respectively. The results indicate that when the catalyst dosage reaches more than 20mg, the yield of photocatalytic regeneration of NADH does not increase with the increase of catalyst dosage. Considering the economic cost, 20mg was selected as the optimal photocatalyst dosage.

[0103] Based on the above-mentioned CdS / MOF-P / SiO2 catalyst dosage of 20 mg, the pH values ​​of the PB buffer solution in the reaction solution (pH 5.0, pH 6.0, pH 7.0, pH 8.0, pH 9.0) were screened. Figure 15 (b) The yields were 66.8%, 67.2%, 66.8%, 73.9%, and 70.15%, respectively. The results showed that, under the same conditions, the reaction was more suitable in a slightly alkaline solution of PB buffer. The yield of photocatalytic regeneration of NADH was the highest at pH 8.0, which was 73.9%. Therefore, PB buffer at pH 8.0 was selected as the optimal reaction solution.

[0104] Based on PB buffer pH 8.0, the types of electron donors (ascorbic acid (AA), methanol (MeOH), EDTA-4Na, triethanolamine (TEOA)) in the reaction were screened. Figure 15 c) The results showed that, under the same conditions, the electron donor triethanolamine (TEOA) had the highest relative yield, therefore, triethanolamine was the optimal electron donor for the reaction.

[0105] The amounts of triethanolamine used as the electron donor in the reaction (5 w / v%, 10 w / v%, 15 w / v%, 20 w / v%, 25 w / v%, 30 w / v%) were screened. Figure 15d) The results show that, under the same conditions, the amount of electron donor TEOA has no significant effect on the yield. Therefore, considering the economic cost, 5 w / v% TEOA is selected as the optimal amount of electron donor.

[0106] Based on the premise that triethanolamine is used as the electron donor in the reaction at a dosage of 5 w / v%, the concentrations of the electron medium [Cp*Rh(bpy)(H2O)]2 in the reaction (0.1 mM, 0.2 mM, 0.25 mM, 0.3 mM, 0.35 mM, 0.4 mM, 0.45 mM, 0.5 mM) were screened. Figure 15 e) The results showed that the yields of the electron mediator [Cp*Rh(bpy)(H2O)]2 at concentrations of 0.1 mM, 0.2 mM, 0.25 mM, 0.3 mM, 0.35 mM, 0.4 mM, 0.45 mM, and 0.5 mM were 67.2%, 74.6%, 75.8%, 74.6%, 76.5%, 77.4%, 77.9%, and 74.6%, respectively, with the highest yield of 77.9% at a concentration of 0.45 mM. Figure 15 f is the spectral scan of NADH regenerated by CdS / MOF-P / SiO2 photocatalysis, showing a characteristic absorption peak of NADH at 340 nm.

[0107] NADH regenerated by CdS / MOF-P / SiO2 photocatalysis was used for P450 enzyme catalysis to generate (E)-1-chloro-1-phenyl-1-butene from (E)-1-chloro-4-phenyl-3-buten-2-ol. Reaction system: Different NAD values ​​were used. + Concentration groups (0mM, 1mM, 3mM, 5mM, 15mM), 20mg photocatalyst, 5% (w / v) TEOA, 0.25mM Rh complex, PB (pH 8.0, 0.1M) added to 10ml, 100mg P450 enzyme, 0.5mM (E)-4-chloro-1-phenyl-1-butene, reacted for 12h, the reaction process is shown below. After the reaction was completed, the sample was extracted with ethyl acetate solution containing 10mM phenylpropanol. The yield was calculated by HPLC using a chiral column CHIRALCEL OD-H. Finally, the reaction yields of 2a were compared, as shown in Table 5.

[0108]

[0109] Table 6. Regenerated NADH-driven P450 enzyme-catalyzed reactions

[0110]

[0111] Photocatalytic regeneration of the coenzyme NADH was used to drive the hydroxylation reaction of (E)-4-chloro-1-phenyl-1-butene catalyzed by the P450 enzyme. Different NAD... +The conversion yields of NADH to 0, 70.4%, 65.2%, 64.2%, and 55.0% for concentrations of 0 mM, 1 mM, 3 mM, 5 mM, and 15 mM, respectively, corresponded to regenerated NADH concentrations of 0 mM, 0.69 mM, 1.98 mM, 3.24 mM, and 8.25 mM. The yields of (E)-1-chloro-4-phenyl-3-buten-2-ol catalyzed by the regenerated coenzyme NADH in the P450 enzyme-catalyzed reaction, as shown in Table 6, were 10.3%, 11.1%, 20.5%, 24.9%, and 31.2%, respectively. This regenerated coenzyme was used for the first time to drive the P450 enzyme-catalyzed reaction to produce (E)-1-chloro-4-phenyl-3-buten-2-ol. As the concentration of regenerated NADH gradually increased, the yield of product 2a of the enzyme-catalyzed reaction showed an increasing trend, indicating that the regenerated coenzyme has biological activity. A green drug synthesis system was successfully constructed by using photocatalytic coenzyme to drive the P450 enzyme-catalyzed reaction of (E)-4-chloro-1-phenyl-1-butene to produce (E)-1-chloro-4-phenyl-3-buten-2-ol.

Claims

1. A preparation method of a high-efficiency composite photocatalytic material based on MOF-loaded CdS, characterized in that Includes the following steps: S1. Add zinc salt solution to imidazole aqueous solution, then add papain for modification, and the reaction yields MOF porous material; then proceed with S2~S4 to prepare a composite photocatalytic material with an external coating membrane, named CdS / MOF-P. S2, using the MOF porous material as a support, adsorbing a solution containing Cd 2+ onto the MOF structure; S3, adding a solution containing S 2+ and MOF adsorbed Cd 2+ to form CdS quantum dots, and the CdS quantum dots are fixed on the MOF; S4. After drying, a highly efficient composite photocatalytic material with CdS supported on MOF is obtained.

2. The preparation method of the high-efficiency composite photocatalytic material based on MOF loaded CdS according to claim 1, characterized in that: In step S1, after the papain reaction, 5% to 10% of orthosilicate solution by volume is added for mixing and modification. Then, through steps S2 to S4, the final composite photocatalytic material is prepared and named CdS / MOF-P / SiO2.

3. The preparation method of the high-efficiency composite photocatalytic material based on MOF loaded CdS according to claim 1 or 2, characterized in that: The Cd-containing 2+ solution and the S-containing 2+ solution are added in the same amount, and the molar concentration is 1-30 mmol. The Cd-containing 2+ The solution includes one of CdSO4, CdCl2, or (CH3COO)2Cd·2H2O solution, containing S. 2+ The solution includes one of Na2S, CH4N2S or C2H5NS solution; In step S1, the reaction temperature is 5℃~30℃, and in step S4, the drying temperature is 40℃~80℃.

4. A high efficient composite photocatalytic material based on MOF supported CdS, characterized in that, It is prepared according to the preparation method described in claim 1 or 2.

5. The application of the high-efficiency composite photocatalytic material based on MOF-supported CdS as described in claim 4 as a photocatalyst in the regeneration of coenzyme NADH.

6. Use according to claim 5, characterized in that: Includes the following steps: (1) The high-efficiency composite photocatalytic material is combined with coenzyme NAD. + An electron donor and an Rh complex were placed in a quartz test tube, and PB buffer was added to obtain mixture A; (2) Place mixture A in a photoreactor and stir in the dark for 10 min. Use 1.5A, 420 nm blue light as the light source and react at a temperature of 15 ℃~30 ℃ to obtain NADH.

7. Use according to claim 6, characterized in that: The electron donor is used at a rate of 5 w / v% to 30 w / v, and is selected from triethanolamine, sodium ethylenediaminetetraacetate, ascorbic acid, or methanol. The Rh complex is [Cp*Rh(bpy)(H2O)]. 2+ The concentration is 0.1~0.5 mM, the concentration of the PB buffer is 0.1M, and the pH value is 5~9.

8. The regenerated coenzyme NADH in the application according to claim 6 or 7 in the construction of regenerated coenzyme-driven P450 enzyme catalysis ( E )-4-chloro-1-phenyl-1-butene reacts to produce ( E Application in the green drug synthesis system of 1-chloro-4-phenyl-3-buten-2-ol.

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