A photocatalyst for NADH regeneration and its preparation method and application

Abstract

The present invention provides a photocatalyst for NADH regeneration and a preparation method and application thereof, belonging to the field of photocatalysis. The preparation method comprises the following steps: (1) Ti3C2T x The method comprises the following steps: uniformly dispersing the mixture in a 0-5 mol / L HCl solution to obtain a mixture A; (2) reacting the mixture A at a temperature of 180°C to 200°C for 10-12 hours to obtain a powder of a precipitate B; (3) uniformly dispersing all the powders in step (2) in a 0-5 mol / L HCl solution to obtain a mixture C; (4) reacting the mixture C at a temperature of 180°C to 200°C for 20-24 hours to obtain a Ti3C2 / TiO2 heterogeneous junction photocatalyst. The photocatalyst of the present invention has a unique layered structure and a high carrier mobility, and extends the light absorption range of the photochemical regeneration of NADH to the visible light region. The process is simple and easy to operate, and exhibits excellent catalytic activity and stability.

Description

Technical Field

[0001] The invention belongs to the technical field of photocatalyst preparation, and in particular relates to a photocatalyst for NADH regeneration and a preparation method and application thereof. Background Art

[0002] The application of biological enzymes is widely present in the biochemical transformation process in nature. Biological enzyme catalysis has the advantages of fast reaction rate, good compatibility, high stereoselectivity, mild reaction conditions and few by-products, and also plays a vital role in the fields of chemical synthesis and new drug development. As the most typical biological enzyme catalyst, oxidoreductase has high catalytic activity, but it also has the disadvantage of requiring coenzymes to show sustained and efficient reaction activity, that is, each oxidoreductase catalyzes one molecule of substrate and requires one molecule of coenzyme to participate. One of the most common coenzymes in nature is nicotinamide adenine dinucleotide (NADH). In view of its high price, achieving efficient and low-cost NADH coenzyme regeneration is obviously of great significance in the enzyme catalysis industry. In order to solve this problem, people have proposed a series of regeneration methods. According to the mechanism of coenzyme regeneration, the methods of coenzyme regeneration can be divided into four categories: enzymatic method, electrochemical method, photochemical method and chemical method. Among them, light-driven regeneration of coenzymes is a method that uses photosensitive materials to capture and utilize clean and sustainable solar energy to achieve high-efficiency and rapid in-situ regeneration of coenzymes. Against the backdrop of increasingly depleted energy, light-driven regenerative coenzymes have broad development prospects.

[0003] In the light-driven regeneration of coenzymes, the role of the photosensitizer is to generate photogenerated electrons and holes under the stimulation of light; the role of the electron mediator is to act as an electron shuttle between the photosensitizer and NAD+, transferring the photogenerated electrons and hydrogen protons in water to the electron acceptor NAD+; the role of the electron donor is to enable the photosensitizer that has lost electrons to regain electrons to prevent the reverse transfer of electrons, thereby reducing the electron-hole recombination rate. The core of the light-driven regeneration of coenzymes lies in the preparation of high-performance photosensitizers. Common photosensitizers are metal oxide photocatalysts, but they have the following defects that seriously restrict their application in the industry: On the one hand, most metal oxides only absorb in the ultraviolet region, and have no absorption or weak absorption in the visible light region, resulting in low energy utilization and unable to avoid the influence of ultraviolet rays on enzymes. On the other hand, more importantly, the photogenerated electrons and photogenerated holes of metal oxide semiconductors are seriously recombinated, so the proportion of effective carriers that can reach the catalyst surface and participate in the reaction is very low, and the photocatalytic efficiency is low. For example, commercial P25 (TiO2) has the advantages of suitable energy band potential, high chemical stability, and high photoelectric conversion efficiency. However, since the bandgap of TiO2 is 3.2eV, which is relatively wide, the specific surface area is small, the visible light response range is narrow, and there is absorption only in the ultraviolet region, and the light energy utilization rate is low. In addition, the photogenerated electron-hole pair recombination rate is high, resulting in reduced photocatalytic activity and catalytic efficiency, which limits its industrial application. At the same time, highly active noble metal-doped metal oxide catalysts have the disadvantages of complex preparation process, poor stability and high cost. Therefore, it is an urgent problem to provide a photocatalyst with simple preparation process, non-toxicity, low cost, high catalytic activity, good stability, low photogenerated carrier recombination efficiency and wide visible light absorption range. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a Ti3C2 / TiO2 heterogeneous junction photocatalyst with a simple and non-toxic preparation process, low cost, and meeting the optimal existence conditions of regeneration enzymes and synthases; the present invention expands the light absorption range of the catalyst to the visible light region, improves energy utilization, avoids the adverse effects of enzyme participation under ultraviolet light, and achieves higher light-responsive catalytic activity; the present invention also applies the Ti3C2 / TiO2 heterogeneous junction photocatalyst to aspects related to photocatalytic coenzyme regeneration, and its regenerated coenzyme NADH yield is significantly improved.

[0005] To achieve the above object, the technical solution adopted by the present invention is: a method for preparing a Ti3C2 / TiO2 heterogeneous junction photocatalyst, the preparation method comprising the following steps:

[0006] (1) Ti3C2T x Evenly dispersed in a HCl solution with a concentration of 0 to 5 mol / L to obtain a mixture A;

[0007] (2) reacting the mixture A at a temperature of 180° C. to 200° C. for 10 to 12 hours, cooling to obtain a precipitate B, washing the precipitate B with water, filtering it with suction, and vacuum drying it to obtain a powder;

[0008] (3) uniformly dispersing the powder obtained in step (2) in a 0-5 mol / L HCl solution to obtain a mixture C;

[0009] (4) The mixture C is reacted at a temperature of 180° C. to 200° C. for 20 to 24 hours, and cooled to obtain a precipitate D. The precipitate D is washed with water, filtered, and vacuum dried to obtain the Ti3C2 / TiO2 heterogeneous junction photocatalyst.

[0010] The purpose of the present invention is to design and synthesize a series of MXene-based new composite photocatalysts starting from metal carbide (Ti3C2). The Ti3C2 / TiO2 heterojunction photocatalyst of the present invention is a new type of graphene-like two-dimensional material, which has a unique layered structure and a high carrier mobility, can reduce the photogenerated carrier recombination efficiency of the photocatalyst and expand its light absorption range to the visible light region. Among them, the hydrochloric acid concentration and hydrothermal reaction time used in the preparation process of the Ti3C2 / TiO2 heterojunction photocatalyst have an important influence on its morphology. (001) Ti3C2 / TiO2 heterojunction photocatalyst, Ti3C2 / TiO2 heterojunction photocatalyst and (111) Ti3C2 / TiO2 heterojunction photocatalyst were synthesized by different hydrochloric acid concentrations of 0mol / L, 0.25mol / L and 5mol / L, respectively. Compared with one-dimensional materials such as TiO2 doped with precious metals, it is a new type of graphene-like two-dimensional material. The preparation method is simpler and the cost is lower, and it has never been used for the regeneration of NADH before.

[0011] As a preferred embodiment of the preparation method of the present invention, in step (1), the volume of the HCl solution is about the same as that of the Ti3C2T x The mass ratio of Ti3C2T x : HCl = 100 mg: 15 mL; in step (1), the concentration of the HCl solution is 0.25-5 mol / L mol / L.

[0012] More preferably, in step (1), the uniform dispersion method is: stirring for 30 minutes and then ultrasonicating for 10 minutes.

[0013] As a preferred embodiment of the preparation method of the present invention, in step (2), the mixture A is reacted at a temperature of 180-200° C. for 10-11 hours and then cooled to obtain a precipitate B; in step (2), the vacuum drying temperature is 60° C. and the time is 6 hours.

[0014] As a preferred embodiment of the preparation method of the present invention, in step (3), the concentration of the HCl solution is 0.25-5 mol / L; and the volume ratio of the mixture C to the mixture A is 1:1.

[0015] More preferably, in step (3), the uniform dispersion method is: stirring for 30 minutes and then ultrasonicating for 10 minutes.

[0016] As a preferred embodiment of the preparation method of the present invention, in step (4), the mixture C is reacted at a temperature of 200° C. for 20 to 22 hours to obtain a precipitate D; in step (4), the vacuum drying temperature is 60° C. and the time is 6 hours.

[0017] As a preferred embodiment of the preparation method of the present invention, in step (1), the concentration of the HCl solution is 0.25 mol / L; in step (2), the mixture A is reacted at a temperature of 180° C. for 10 h to obtain a precipitate B.

[0018] As a preferred embodiment of the preparation method of the present invention, in step (3), the concentration of the HCl solution is 0.25 mol / L; in step (4), the mixture C is reacted at a temperature of 200° C. for 20 h to obtain a precipitate D.

[0019] As a more preferred embodiment of the preparation method of the present invention, in the solution A in step (1), the concentration of the HCl solution is 0.25 mol / L; in step (2), the hydrothermal reaction temperature is 180° C. and the time is 10 h; in step (3), the concentration of the HCl solution is 0.25 mol / L; in step (4), the hydrothermal reaction temperature is 200° C. and the time is 20 h.

[0020] When the concentration of the HCl solution and the temperature and time of the hydrothermal reaction are as mentioned above, the performance of the prepared Ti3C2 / TiO2 heterogeneous junction photocatalyst is better.

[0021] The present invention also provides a Ti3C2 / TiO2 heterogeneous junction photocatalyst prepared by any of the above-mentioned methods for preparing the Ti3C2 / TiO2 heterogeneous junction photocatalyst.

[0022] The Ti3C2 / TiO2 heterojunction photocatalyst prepared by the above method has a unique layered structure and a high carrier mobility, which extends its light absorption range to the visible light region, improves energy utilization, avoids the adverse effects of enzyme participation under ultraviolet light, and can also reduce the photogenerated carrier recombination efficiency of the photocatalyst. Compared with one-dimensional materials such as TiO2 doped with precious metals (traditional photocatalysts), the preparation of Ti3C2 / TiO2 heterojunction photocatalysts is simpler and less expensive, and is a photocatalyst that meets the optimal conditions for the existence of regenerative enzymes and synthesizing enzymes, so as to achieve higher light-responsive catalytic activity.

[0023] The present invention also provides an application of the above-mentioned Ti3C2 / TiO2 heterogeneous junction photocatalyst in the regeneration of coenzyme NADH, and the application comprises the following steps:

[0024] (1) adding the above-mentioned photocatalyst to coenzyme NAD+, electron donor, and metal complex to obtain a mixture E;

[0025] (2) Place the mixture E in a reaction vessel, under nitrogen flow throughout the process, use visible light or ultraviolet light as the light source, the irradiation distance is 15 cm to 1 m, the temperature is 25 to 37° C., and the pH value is 6.5 to 7.5, and react to obtain NADH;

[0026] (3) Shade the mixture E for 15 minutes to obtain a blank sample, and then take samples every hour until the eighth sample is taken; the sample is centrifuged at 20°C and 12000 r / min for 15 minutes, and the supernatant is diluted 10 times and its absorbance at 340 nm is measured, and the NADH yield is calculated using the NADH standard curve.

[0027] The Ti3C2 / TiO2 heterogeneous junction photocatalyst of the present invention can show excellent catalytic performance when used for the regeneration of coenzyme NADH.

[0028] In the application of coenzyme NADH regeneration, electron donors are an important link in the light-driven enzyme catalytic system, because the electrons required to generate products in the system come from electron donors. At the same time, electron donors are also an important factor affecting the catalytic efficiency of the system. After the photosensitizer is photoexcited, the electrons in the valence band are excited to transition to the conduction band to generate photogenerated electrons, and electron holes are generated in the valence band. Electron holes require electron donors to quench holes. The quenching efficiency will affect the electron transfer efficiency, and then affect the catalytic efficiency of the system. Finally, in the light-driven enzyme catalytic composite system based on coenzymes, electron donors provide electrons under light induction through photosensitizers, and electrons are eventually transferred to enzymes, thereby catalyzing redox reactions. Electron donors are a reducing substance that can promptly eliminate photogenerated holes in the reaction system and form oxidized compounds to improve the electron transfer efficiency. The selection of electron donors requires that the oxidized compounds formed after their own oxidation cannot interfere with the normal operation of the photochemical cycle. The Pka value of the electron donor is close to the pH of the system to provide electrons most effectively, and a lower oxidation potential is required. Some common electron donors include lactic acid, ascorbic acid, triethanolamine (TEOA), ethylenediaminetetraacetic acid (EDTA) and 2-(N-morpholino)ethanesulfonic acid (MES). Among them, the best electron donors are TEOA and EDTA, which can achieve single electron oxidation and improve the catalytic efficiency of the system. The generated oxidation intermediates have no effect on the system and are highly stable. In addition, their Pka values ​​are between 5-8, which is consistent with the catalytic pH range of most enzyme reactions.

[0029] Metal complexes such as chiral diamine ligands of rhodium, bipyridine ligands of rhodium [Cp*Rh(bpy)H2O] 2+ and [Rh(dmbpy)2Cl2] + , rhodium carbon heterophenanthrene ligands [Cp*Rh(Me4phen)Cl]Cl and [(η5-C5Me5)Rh(3,4,7,8-Me4-1,10-phen)Cl]Cl as electron mediators and hydride transfer agents, which can not only help the photocatalyst transfer electrons and increase the stability and activity of NADH, but also prevent the formation of inactive NADH isomers and (NAD)2 dimers. The special technical solution uses [Cp*Rh(bpy)H] + , can be obtained by chemical or electrochemical procedures from [Cp*Rh(bpy)(H2O)] 2+ It is obtained and regenerated in the presence of NAD(P)+. It is used as a hydride transfer reagent on NAD(P)+ to produce only the enzymatically active 1,4-NAD(P)H isomer.

[0030] As a preferred embodiment of the present invention for use in the regeneration of coenzyme NADH, in step (1), the electron donor is one of EDTA-2Na, EDTA-4Na, TEOA, and lactic acid; the metal complex is [Cp*Rh(bpy)(H2O)]2; the ratio of the components in the mixture E is: photocatalyst: coenzyme NAD+: electron donor: metal complex = (30-45) mg: 1 mmol: 0.15 mmol: 0.25 mmol.

[0031] Preferably, the metal complex may include not only [Cp*Rh(bpy)(H2O)]2, but also common metal complexes in the art, and are not limited to those described herein.

[0032] As a more preferred embodiment of the present invention in the application of coenzyme NADH regeneration, in step (1), the electron donor is EDTA-2Na; in step (1), the ratio of each component in the mixture E is: photocatalyst: coenzyme NAD+: electron donor: metal complex = 45mg: 1mmol: 0.15mmol: 0.25mmol. In step (2), the light source is a 300W xenon lamp, the irradiation distance is 65cm, the pH value is 7, and the temperature is 30°C.

[0033] Compared with its electron acceptor, different types of photocatalysts showed good performance in the coenzyme NADH regeneration reaction using EDTA-2Na as an electron donor. The best catalytic performance was shown when the ratio of each component in the mixture E was: photocatalyst: coenzyme NAD+: electron donor: metal complex = 45mg:1mmol:0.15mmol:0.25mmol.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] (1) The process of NADH regeneration catalyzed by Ti3C2 / TiO2 heterogeneous photocatalyst is simple and easy, with low operation complexity and stable activity of the synthesized material. Compared with one-dimensional materials such as TiO2, its regeneration coenzyme NADH yield is significantly improved.

[0036] (2) The Ti3C2 / TiO2 heterojunction photocatalyst has a unique layered structure and high carrier mobility, which can reduce the recombination efficiency of photogenerated carriers in the photocatalyst and show excellent catalytic performance for the regeneration of NADH;

[0037] (3) The photochemical regeneration of NADH catalyzed by the Ti3C2 / TiO2 heterogeneous photocatalyst extends its light absorption range to the visible light region. The regeneration process can be carried out under the irradiation of a xenon lamp, with high energy utilization and avoiding the influence of ultraviolet light on the enzyme;

[0038] (4) The regeneration process does not require the participation of enzymes or the toxic electron mediator methyl amethyst, which not only reduces costs but also avoids the drawback of being difficult to control due to the different optimal existence conditions of the regeneration enzyme and the synthesis enzyme. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is the XRD comparison diagram of Examples 1-4 of the present invention and Comparative Example 2.

[0040] Figure 2 It is a comparison chart of infrared spectra of Examples 1-4 of the present invention and Comparative Example 2.

[0041] Figure 3 It is a comparison chart of NADH yields of Examples 1-4 of the present invention and Comparative Example 1 under the condition that the electron donor is EDTA-2Na.

[0042] Figure 4 It is a comparison chart of NADH yields of Examples 1-4 of the present invention and Comparative Example 1 when the electron donor is EDTA-4Na.

[0043] Figure 5 It is a comparison chart of NADH yields of Examples 1-4 of the present invention and Comparative Example 1 when the electron donor is TEOA.

[0044] Figure 6 It is a comparison chart of NADH yields of Examples 1-4 of the present invention and Comparative Example 1 under the condition that the electron donor is lactic acid.

[0045] Figure 7It is a comparison chart of NADH yields of Examples 1-4 of the present invention and Comparative Example 1 under the conditions of EDTA-2Na, EDTA-4Na, TEOA, and lactic acid as electron donors, respectively.

[0046] Figure 8 It is the scanning electron microscope image of Example 1-4 of the present invention. DETAILED DESCRIPTION

[0047] To better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific examples. The reagents used in the following examples can all be purchased from commercial channels.

[0048] Example 1

[0049] As a preparation method of a Ti3C2 / TiO2 heterogeneous junction photocatalyst according to an embodiment of the present invention, the method comprises the following steps: weighing 100 mg Ti3C2T x Add to 15mL of 0.25mol / L HCl, stir the mixture for 30min, and ultrasonicate for 10min to make it uniform, to obtain mixture A. Then transfer it to a 100mL reactor, react at 180℃ for 10h under hydrothermal conditions, and obtain precipitate B after cooling. Wash it with water, filter it and vacuum dry it at 60℃ for 6 hours to obtain powder. Add the obtained sample powder to 15mL of 0.25mol / L HCl, stir for 30min, and ultrasonicate for 10min to make it uniform, to obtain mixture C. Then transfer mixture C to a 100mL reactor, react at 200℃ for 20h under hydrothermal conditions, and obtain precipitate D after cooling. Wash precipitate D with water, filter it and vacuum dry it at 60℃ for 6 hours. The obtained powder is the Ti3C2 / TiO2 heterogeneous junction photocatalyst for NADH regeneration;

[0050] The Ti3C2 / TiO2 heterogeneous junction photocatalyst prepared in this example was used for NADH regeneration reaction, and the regeneration reaction included the following steps: using a 300W xenon lamp as the light source (irradiation distance of 65cm), 45mg of the Ti3C2 / TiO2 heterogeneous junction photocatalyst was added to 30mL of 5mmol / L EDTA-2Na, EDTA-4Na, TEOA, and lactic acid electron donor solutions, respectively; after stirring for 15min and ultrasonic treatment for 15min, 0.25mmol of the metal complex [Cp*Rh(bpy)(H2O)]2 was added, and 1mmol of NAD+ standard substance was added; at a temperature of 30°C, a pH value of 7, and nitrogen was passed throughout the process, the reaction was shielded from light for 15min to obtain a blank sample. After that, samples were taken every hour until the eighth sample was taken. After sampling, the samples were centrifuged at 20°C and 12000r / min for 15min. The supernatant was diluted 10 times and its absorbance at 340nm was measured. The NADH yield was calculated using the NADH standard curve.

[0051] The Ti3C2 / TiO2 heterogeneous photocatalyst prepared above was subjected to NADH regeneration reaction under the conditions of EDTA-2Na, EDTA-4Na, TEOA, and lactic acid electron donor, such as Figure 7 As shown, the yields of NADH were 82.1%, 77.5%, 39.7% and 31.3%, respectively.

[0052] Example 2

[0053] As a preparation method of a (001) Ti3C2 / TiO2 heterogeneous junction photocatalyst according to an embodiment of the present invention, the method comprises the following steps: weighing 100 mg Ti3C2T x Add to 15mL deionized water, stir the mixture for 30min, and ultrasonicate for 10min to make it uniform, to obtain mixture A. Then transfer it to a 100mL reactor, react at 180℃ for 10h under hydrothermal conditions, and obtain precipitate B after cooling. Wash it with water, filter it and vacuum dry it at 60℃ for 6 hours to obtain powder. Add the obtained sample powder to 15mL deionized water, stir for 30min, and ultrasonicate for 10min to make it uniform, to obtain mixture C. Then transfer mixture C to a 100mL reactor, react at 200℃ for 20h under hydrothermal conditions, and obtain precipitate D after cooling. Wash precipitate D with water, filter it and vacuum dry it at 60℃ for 6 hours. The obtained powder is the (001)Ti3C2 / TiO2 heterogeneous junction photocatalyst for NADH regeneration;

[0054] The (001) Ti3C2 / TiO2 heterogeneous junction photocatalyst prepared in this example was subjected to NADH regeneration reaction. Except that the catalyst was (001) Ti3C2 / TiO2 heterogeneous junction photocatalyst which was different from Example 1, other regeneration reaction conditions were the same as those in Example 1.

[0055] The (001) Ti3C2 / TiO2 heterogeneous junction photocatalyst prepared above was subjected to NADH regeneration reaction under the conditions of EDTA-2Na, EDTA-4Na, TEOA, and lactic acid electron donor, such as Figure 4 As shown, the yields of NADH were 39.7%, 40.1%, 12.6% and 9.51%, respectively.

[0056] Example 3

[0057] As a method for preparing a (111) Ti3C2 / TiO2 heterogeneous junction photocatalyst according to an embodiment of the present invention, the method comprises the following steps: weighing 100 mg Ti3C2T x Add to 15mL of 5mol / L HCl, stir the mixture for 30min, and ultrasonicate for 10min to make it uniform, to obtain mixture A. Then transfer it to a 100mL reactor, react at 180℃ for 10h under hydrothermal conditions, and obtain precipitate B after cooling. Wash it with water, filter it, and vacuum dry it at 60℃ for 6 hours to obtain powder. Add the obtained sample powder to 15mL of 5mol / L HCl, stir for 30min, and ultrasonicate for 10min to make it uniform, to obtain mixture C. Then transfer mixture C to a 100mL reactor, react at 200℃ for 20h under hydrothermal conditions, and obtain precipitate D after cooling. Wash precipitate D with water, filter it, and vacuum dry it at 60℃ for 6 hours. The obtained powder is the (111)Ti3C2 / TiO2 heterogeneous junction photocatalyst for NADH regeneration;

[0058] The (111)Ti3C2 / TiO2 heterogeneous junction photocatalyst prepared in this example was subjected to NADH regeneration reaction. Except that the catalyst was (111)Ti3C2 / TiO2 heterogeneous junction photocatalyst which was different from Example 1, other regeneration reaction conditions were the same as those in Example 1.

[0059] The (111)Ti3C2 / TiO2 heterogeneous photocatalyst prepared above was subjected to NADH regeneration reaction under the conditions of EDTA-2Na, EDTA-4Na, TEOA, and lactic acid electron donor, such as Figure 4 As shown, the yields of NADH were 31.3%, 25.9%, 11.4% and 15.4%, respectively.

[0060] Example 4

[0061] As a preparation method of a Ti3C2 / TiO2 heterogeneous junction photocatalyst after 72h treatment in an embodiment of the present invention, the method comprises the following steps: adding the sample powder prepared by the method of Example 1 to 15mL of HCl with a concentration of 0.25mol / L, stirring the mixture for 30min, ultrasonicating for 10min to make it uniform, then transferring it to a 100mL reactor, reacting at 180°C for 10h under hydrothermal conditions, and after cooling, washing the sample with water, filtering it and vacuum drying it at 60°C for 6 hours; adding the obtained sample powder to 15mL of HCl with a concentration of 0.25mol / L, stirring the mixture for 30min, ultrasonicating for 10min to make it uniform, then transferring it to a 100mL reactor, reacting at 200°C for 20h under hydrothermal conditions, and after cooling, washing the final sample with water, filtering it and vacuum drying it for 6 hours; the obtained powder is Ti3C2 / TiO2 after 72h treatment;

[0062] The NADH regeneration reaction was performed on the Ti3C2 / TiO2 heterogeneous junction photocatalyst treated for 72 hours prepared in this example. Except that the catalyst was the Ti3C2 / TiO2 heterogeneous junction photocatalyst treated for 72 hours, which was different from that in Example 1, the other regeneration reaction conditions were the same as those in Example 1.

[0063] The Ti3C2 / TiO2 heterogeneous photocatalyst prepared above after 72h treatment was subjected to NADH regeneration reaction under the conditions of EDTA-2Na, EDTA-4Na, TEOA, and lactic acid electron donor, such as Figure 4 As shown, the yields of NADH were 50.2%, 47.8%, 34.9% and 19.5%, respectively.

[0064] Example 5

[0065] As a method for preparing a Ti3C2 / TiO2 heterogeneous junction photocatalyst according to an embodiment of the present invention, the method has the same regeneration reaction conditions as in Example 1, except that the hydrothermal conditions in step (2) are 190°C for reaction for 12 hours, and the hydrothermal conditions in step (4) are 190°C for reaction for 24 hours, which are different from those in Example 1.

[0066] The Ti3C2 / TiO2 heterogeneous junction photocatalyst prepared in this example was subjected to NADH regeneration reaction. Except for the catalyst preparation conditions and the addition mass of 40 mg, which were different from Example 1, the other regeneration reaction conditions were the same as those in Example 1.

[0067] The Ti3C2 / TiO2 heterogeneous junction photocatalyst prepared above was subjected to NADH regeneration reaction under the electron donor conditions of EDTA-2Na, EDTA-4Na, TEOA and lactic acid, and the yields of NADH obtained were 39.7%, 30.4%, 19.6% and 16.3% respectively.

[0068] Example 6

[0069] As a method for preparing a Ti3C2 / TiO2 heterogeneous junction photocatalyst according to an embodiment of the present invention, the method has the same regeneration reaction conditions as in Example 1, except that the hydrothermal conditions in step (2) are 200°C for reaction for 11 hours, and the hydrothermal conditions in step (4) are 200°C for reaction for 22 hours, which are different from those in Example 1.

[0070] The Ti3C2 / TiO2 heterogeneous junction photocatalyst prepared in this example was subjected to NADH regeneration reaction. Except for the catalyst preparation conditions and the addition mass of 45 mg which were different from Example 1, other regeneration reaction conditions were the same as those in Example 1.

[0071] The Ti3C2 / TiO2 heterogeneous photocatalyst prepared above was subjected to NADH regeneration reaction under the conditions of EDTA-2Na, EDTA-4Na, TEOA, and lactic acid electron donor, such as Figure 4 As shown, the yields of NADH were 46.3%, 38.2%, 22.7% and 19.4%, respectively.

[0072] Example 7

[0073] As a method for preparing a Ti3C2 / TiO2 heterogeneous junction photocatalyst according to an embodiment of the present invention, the method has the same regeneration reaction conditions as Example 1, except that the hydrothermal conditions in step (2) are 180°C for reaction for 10 hours, and the hydrothermal conditions in step (4) are 180°C for reaction for 20 hours, which are different from Example 1.

[0074] The Ti3C2 / TiO2 heterogeneous junction photocatalyst prepared in this example was subjected to NADH regeneration reaction. Except for the catalyst preparation conditions and the addition mass of 35 mg which were different from Example 1, other regeneration reaction conditions were the same as those in Example 1.

[0075] The Ti3C2 / TiO2 heterogeneous photocatalyst prepared above was subjected to NADH regeneration reaction under the conditions of EDTA-2Na, EDTA-4Na, TEOA, and lactic acid electron donor, such as Figure 4 As shown, the yields of NADH were 30.4%, 25.1%, 10.7% and 14.8%, respectively.

[0076] Example 8

[0077] As a method for preparing a Ti3C2 / TiO2 heterogeneous junction photocatalyst according to an embodiment of the present invention, the method has the same regeneration reaction conditions as in Example 1, except that the hydrothermal conditions in step (2) are 190°C for reaction for 10 hours, and the hydrothermal conditions in step (4) are 200°C for reaction for 20 hours, which are different from those in Example 1.

[0078] The Ti3C2 / TiO2 heterogeneous junction photocatalyst prepared in this example was subjected to NADH regeneration reaction. Except for the catalyst preparation conditions and the addition mass of 45 mg which were different from Example 1, other regeneration reaction conditions were the same as those in Example 1.

[0079] The Ti3C2 / TiO2 heterogeneous photocatalyst prepared above was subjected to NADH regeneration reaction under the conditions of EDTA-2Na, EDTA-4Na, TEOA, and lactic acid electron donor, such as Figure 4 As shown, the yields of NADH were 48.9%, 40.1%, 26.7% and 21.5%, respectively.

[0080] Comparative Example 1

[0081] As a comparative example of the present invention, chemically pure TiO2 produced by Macklin was used to carry out NADH regeneration reaction. Except that the catalyst was commercial TiO2, other conditions of the regeneration reaction were the same as those of Examples 1-4.

[0082] The commercial TiO2 catalyst is subjected to NADH regeneration reaction under the conditions of EDTA-2Na, EDTA-4Na, TEOA, and lactic acid electron donor, such as Figure 4 As shown, the yields of NADH were 77.8%, 64.2%, 15.9% and 24.1%, respectively.

[0083] Comparative Example 2

[0084] As a comparative example of the present invention, a method for preparing Ti3C2 comprises the following steps: weighing 100 mg Ti3C2T x Add 15mL of 0.25mol / L HCl, stir the mixture for 30min, ultrasonicate for 10min to make it uniform, then transfer it to a 100mL reactor and react at 180℃ for 10h under hydrothermal conditions. After cooling, wash the sample with water, filter it and vacuum dry it at 60℃ for 6h to obtain Ti3C2 powder.

[0085] 1) Material morphology and structure analysis

[0086] like Figure 1 As shown, in Example 1, characteristic peaks of rutile TiO2 (PDF78-1510) appear at 27.26°, 53.69°, and 54.87°, characteristic peaks of anatase TiO2 (PDF 21-1272) appear at 25.16°, and obvious characteristic peaks of layered Ti3C2 appear near 17.64°. Figure 8(a) and (e) show the morphology of the Ti3C2 / TiO2 heterogeneous junction photocatalyst prepared in Example 1. The sample of Example 2 without adding hydrochloric acid mainly corresponds to the card of anatase and layered Ti3C2, Figure 8 (b) and (f) show the morphology of the (001) Ti3C2 / TiO2 heterogeneous junction photocatalyst prepared in Example 2. The sample in Example 3 with 5 mol / L hydrochloric acid added mainly corresponds to the cards of rutile and layered Ti3C2, Figure 8 (c) and (g) show the morphology of the (111)Ti3C2 / TiO2 heterogeneous junction photocatalyst prepared in Example 3. As the hydrothermal treatment is prolonged, the titanium dioxide nanosheets continue to grow on the titanium carbide nanosheets. After 72 hours of treatment, although the Ti3C2 / TiO2 heterogeneous junction photocatalyst has characteristic peaks of both Ti3C2 and TiO2, the diffraction peak is mainly that of TiO2, as shown in Figure 1. Figure 8 (d) and (h) show that the main component is TiO2. This is because the Ti3C2 nanosheets are basically converted into TiO2 nanosheets due to the long hydrothermal time. Figure 2 In the infrared spectrum shown, 1660 cm -1 and 3500cm -1 The broad peaks at 550cm-1 can be attributed to -OH adsorbed on Ti3C2 and TiO2, which are Ti-O stretching vibration peaks. This further illustrates that there is -OH adsorption on the surface of titanium carbide, so there is Ti-O stretching vibration. -1 The nearby peak is the stretching vibration peak of O-Ti-O. The stronger the vibration amplitude, the higher the TiO2 content.

[0087] 2) Analysis of catalytic performance of NADH regeneration reaction

[0088] From Table 1 and Figure 3-7 It can be obtained that Example 1 is better than Examples 2 and 3, indicating that the Ti3C2 / TiO2 heterogeneous junction photocatalyst prepared with a hydrochloric acid concentration of 0.25 mol / L has better catalytic performance than (001) Ti3C2 / TiO2 and (111) Ti3C2 / TiO2. Although Example 4 is not as good as the performance of Example 1, it is better than Examples 2-3, indicating that the catalyst of Example 1 still has significant catalytic performance even after aging. Example 1 is better than Examples 5-8, indicating that the optimal conditions for the first step of the hydrothermal reaction are 180 degrees for 10 hours, the optimal conditions for the second step of the hydrothermal reaction are 200 degrees for 20 hours, the optimal amount of catalyst added is 45 mg, and the most suitable electron donor is EDTA-2Na. The performance of Example 1 is better than the commercial TiO2 in Comparative Example 1, and the yield of regenerated coenzyme NADH is significantly improved.

[0089] Table 1 Comparison of NADH yields between Examples 1-8 and Comparative Examples 1-2

[0090]

[0091] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. Application of a Ti3C2 / TiO2 heterogeneous junction photocatalyst in the regeneration of coenzyme NADH, characterized in that: The preparation method of the Ti3C2 / TiO2 heterogeneous junction photocatalyst comprises the following steps: (1) Ti3C2 T x Evenly dispersed in a HCl solution with a concentration of 0-5 mol / L to obtain a mixture A; (2) subjecting the mixture A to a hydrothermal reaction at a temperature of 180°C to 200°C for 10 to 12 h, cooling the mixture to obtain a precipitate B, washing the precipitate B with water, filtering the precipitate, and vacuum drying the precipitate to obtain a powder; (3) uniformly dispersing the powder obtained in step (2) in a 0-5 mol / L HCl solution to obtain a mixture C; (4) The mixture C is subjected to a hydrothermal reaction at a temperature of 180° C. to 200° C. for 20 to 24 hours, and then cooled to obtain a precipitate D. The precipitate D is washed with water, filtered, and vacuum dried to obtain the Ti3C2 / TiO2 heterogeneous junction photocatalyst; In step (1), the volume of HCl solution is equal to that of Ti3C2 T x The mass ratio of Ti3C2 T x : HCl = 100 mg: 15 mL; In step (1), the concentration of the HCl solution is 0.25 mol / L; in step (2), the hydrothermal reaction temperature is 180° C. and the time is 10 h; in step (3), the concentration of the HCl solution is 0.25 mol / L; in step (4), the hydrothermal reaction temperature is 200° C. and the time is 20 h.

2. The use according to claim 1, characterized in that: In step (2), the vacuum drying temperature is 60° C. and the time is 6 hours.

3. The use according to claim 1, characterized in that: The volume ratio of the mixture C to the mixture A is 1:

1.

4. The use according to claim 1, characterized in that: In step (4), the vacuum drying temperature is 60° C. and the time is 6 h.

5. The use according to claim 1, characterized in that: The application comprises the following steps: (1) adding the Ti3C2 / TiO2 heterogeneous photocatalyst to the coenzyme NAD+, the electron donor, and the metal complex to obtain a mixture E; (2) Mixture E is passed through nitrogen throughout the process, with visible light or ultraviolet light as the light source, the irradiation distance is 15-100 cm, and NADH is obtained under the conditions of temperature of 25-37°C and pH of 6.5-7.

5.

6. The use according to claim 5, characterized in that: The electron donor is one of EDTA-2Na, EDTA-4Na, TEOA and lactic acid; the metal complex is [Cp*Rh(bpy)(H2O)] 2+ ; The ratio of each component in the mixture E is: photocatalyst: coenzyme NAD+: electron donor: metal complex = (30-45) mg: 1 mmol: 0.15 mmol: 0.25 mmol.

7. The use according to claim 5, characterized in that: The ratio of each component in the mixture E is: photocatalyst: coenzyme NAD+: electron donor: metal complex = 45 mg: 1 mmol: 0.15 mmol: 0.25 mmol; the light source is a 300W xenon lamp, the irradiation distance is 65 cm, the pH value is 7, and the temperature is 30°C.

Images