Photoelectricity synergic driving method for continuous cascade production of alanine

Abstract

The application discloses a photoelectricity collaborative driven continuous cascade production method of alanine, and is characterized by comprising the following steps: taking an aqueous solution containing nitrate and a fixing agent as an electrolyte, and generating a solution of a hydroxylamine intermediate under the action of a cathode catalytic electrode; continuously conveying the hydroxylamine intermediate obtained by hydrolysis to a solution containing lactic acid and a photocatalyst, and preparing alanine through photocatalysis; and the cathode catalytic electrode comprises a kind of electrocatalytic material which promotes the conversion of nitrate into hydroxylamine. The application solves the problems that hydroxylamine is unstable in an electrocatalytic system and is difficult to be directly output and utilized by constructing a continuous cascade system in which electrocatalytic nitrogen supply, intermediate hydrolysis fixation and photocatalytic synthesis are sequentially connected, improves the availability and utilization efficiency of the nitrogen-containing intermediate, and realizes the synchronous performance of nitrate-containing wastewater treatment and alanine preparation.

Description

Technical Field

[0001] This invention relates to the field of photoelectrocatalysis technology, specifically to a photoelectro-co-driven continuous cascade production method for alanine. Background Technology

[0002] Alanine, an important α-amino acid, is one of the basic components of human proteins and is widely used in food additives, pharmaceutical intermediates, feed, cosmetics, and biodegradable materials, possessing high industrial application value. With the development of green manufacturing and sustainable chemistry, developing alanine preparation methods that utilize widely available raw materials, have low energy consumption, minimal environmental impact, and are suitable for continuous production has become an important technological direction in this field.

[0003] Existing alanine preparation technologies mainly include chemical synthesis, bio-fermentation, and catalytic conversion. Traditional chemical synthesis can usually be achieved through routes such as the Strecker reaction, which uses aldehydes and cyanides as raw materials to prepare amino acids. While these methods have mature reaction pathways, they generally suffer from problems such as high toxicity of raw materials, high safety risks, heavy separation and purification burdens, and reliance on fossil resources for carbon sources, making it difficult to meet the development requirements of green chemistry and low-carbon manufacturing. Another published patent (US20040092725A1) proposes reacting organic acids with ammonia or ammonium salts under high temperature and high pressure water conditions to introduce amino groups and prepare amino acids; however, this type of method typically has high requirements for equipment and operating conditions, and the system still consumes a significant amount of energy.

[0004] Bio-fermentation typically utilizes engineered bacteria or metabolically regulated strains to produce L-alanine from renewable carbon sources such as glucose and xylose, and is one of the more mature industrial routes currently available. Existing patents, such as CN101665813A, CN115651939A, and CN119162265A, disclose methods for directly fermenting L-alanine using microorganisms such as *E. coli*, focusing on improvements in strain construction, culture medium composition, fermentation control, and equipment optimization. While this technology offers advantages such as a wide range of substrate sources and relatively mild conditions, it generally suffers from problems including long fermentation cycles, complex process control, long equipment usage time, limited continuity, and high downstream separation costs.

[0005] In recent years, catalytic conversion methods driven by renewable energy have attracted attention. Existing research and patents have attempted to convert lactic acid, polylactic acid (PLA), and their derivative intermediates into alanine through thermocatalysis, photocatalysis, or electrocatalysis. Electrocatalytic synthesis typically uses pyruvate and hydroxylamine as raw materials, synthesizing alanine via a CN-C coupling reaction. However, it still suffers from low intermediate utilization, numerous side reactions, and low overall yield, limiting its large-scale application. Photocatalytic synthesis mainly uses lactic acid and ammonia as raw materials, but the volatility of ammonia makes it difficult to guarantee high nitrogen source utilization. For example, in 2024, the team led by Researcher Chen Yong at the Institute of Physics and Chemistry, Chinese Academy of Sciences, proposed a photocatalytic strategy for preparing alanine from lactic acid and ammonia. This catalyst achieved a yield of 2.4 mmol g / L. cat. -1 h -1 Catalytic activity. The above routes show that the catalytic production of alanine using lactic acid / PLA as a carbon source is feasible, but most still rely on ammonia water as an external nitrogen source. The production of industrial ammonia usually relies on the Haber-Bosch process, which is characterized by high energy consumption and high carbon emissions. At the same time, ammonia in the aqueous phase also has problems such as volatilization, limited utilization rate (<1%), and insufficient mass transfer efficiency.

[0006] On the other hand, the development of electrochemical nitrogen-containing small molecule synthesis technology has provided new possibilities for the green supply of nitrogen sources. Existing patents (such as WO2020028570A1) propose that nitrates can be reduced to nitrogen-containing products such as ammonia through electrochemical means, thereby replacing some traditional industrial ammonia production routes. Related disclosures also show that electrocatalytic systems can achieve the directed conversion of nitrates / nitrites to intermediates such as hydroxylamine and ammonia, providing a more reactive nitrogen source for subsequent CN-coupling reactions. Meanwhile, recent literature has also reported the approach of preparing amino acids through CN-coupling of nitrates and α-keto acids, indicating the development potential of "pollutant nitrogen source resource utilization + high-value nitrogen-containing product synthesis".

[0007] However, existing technologies still have the following shortcomings: First, most existing catalytic routes for alanine production rely on external ammonia or ammonia water as nitrogen sources, failing to effectively break free from the high-energy-consuming industrial ammonia production system. Second, carbon source activation and nitrogen source activation are usually carried out in independent steps, making it difficult to achieve in-situ, efficient, and continuous linkage of intermediates, thus limiting nitrogen utilization and overall space-time yield. Third, most systems remain in a batch reaction mode, making it difficult to balance continuous production and process stability. Fourth, waste resources, especially biomass or plastic waste containing lactic acid structural units, as well as nitrates / nitro nitrogenous compounds in nitrogen-containing wastewater, have not yet been synergistically utilized for high-value production within the same system. Therefore, it is still necessary to develop a new method that can couple photocatalysis and electrocatalysis processes, achieve simultaneous activation of carbon and nitrogen sources, and is suitable for continuous cascade production of alanine. Summary of the Invention

[0008] This invention addresses the problems in existing alanine production technologies, such as high dependence on ammonia as a nitrogen source, low nitrogen source utilization, difficulty in continuously linking carbon source activation and nitrogen source activation, and the unstable accumulation of hydroxylamine in the electrocatalytic system, which easily leads to further reduction to ammonia. It provides a photoelectro-coordinated continuous cascade production method for alanine. In the electrocatalytic nitrate reduction stage, the generated hydroxylamine is immobilized in situ as a hydrolyzable intermediate that releases hydroxylamine. After being output, it is hydrolyzed and released, then continuously transported to the lactic acid photocatalytic reaction system for CN coupling, thereby achieving synergistic treatment of nitrogenous wastewater and efficient alanine production.

[0009] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A photoelectric co-driven continuous cascade production method for alanine includes the following steps: using an aqueous solution containing nitrate and a fixative as the electrolyte, a solution for electrocatalytically generating a hydroxylamine intermediate is prepared under the action of a cathode catalytic electrode; the hydroxylamine solution obtained by hydrolyzing the hydroxylamine intermediate is continuously transported to a solution containing lactic acid and a photocatalyst, and alanine is obtained by photocatalysis. The cathode catalytic electrode contains an electrocatalytic material that promotes the conversion of nitrate ions into hydroxylamine.

[0010] This invention utilizes a combined electrocatalytic and photocatalytic system to produce alanine. Hydroxylamine is prepared from nitrate via electrocatalysis, and then reacted with lactic acid via photocatalysis to obtain alanine. This avoids the use of ammonia as a nitrogen source and solves the problems of high volatility and low utilization rate associated with ammonia. The method of this invention achieves high alanine yield, simultaneously treating nitrate wastewater and synthesizing alanine. It removes pollutants while preparing high-value-added chemicals, significantly increasing the alanine production rate and combining environmental treatment with resource utilization.

[0011] The hydroxylamine solution is fed at a rate controlled by a peristaltic pump, with the feed rate being 0.05-1 mL / min. The continuous feed rate of the hydroxylamine solution is controlled by adjusting the peristaltic pump speed, with the feed rate being 0.05-1.0 mL / min, more preferably 0.08-0.30 mL / min, and even more preferably 0.1 mL / min. By controlling the feeding method of nitrogen-containing species, the instantaneous concentration of hydroxylamine in the photocatalytic system is controlled, improving reaction stability and further enhancing the alanine production rate, which is beneficial for process scale-up and continuous production.

[0012] Preferably, the fixative comprises acetone.

[0013] The electrocatalytic material includes Cu-MnO2H x Any one of FePC-KB, I-Bi, ZnPc MDE, or Bi film / CFP, where x represents the lattice hydrogen content in the material.

[0014] Within the photocatalytic reactor, a ruthenium / molybdenum disulfide (Ru / MoS2) photocatalyst generates photogenerated carriers under illumination, promoting the oxidative conversion of lactic acid substrate into pyruvate. The pyruvate further reacts with hydroxylamine to generate alanine, thus achieving a cascade reaction process where nitrate wastewater treatment and alanine preparation occur simultaneously. The photocatalyst can be any one or more of the following: ruthenium / molybdenum disulfide photocatalyst, ruthenium / cadmium sulfide, cadmium sulfide nanosheets, and cobalt phosphide / cadmium sulfide.

[0015] The preparation of the ruthenium / molybdenum disulfide photocatalyst includes the following steps: mixing and stirring ruthenium salt, molybdenum disulfide and sodium borohydride for aging; after the reaction is completed, the product is separated, washed and dried to obtain the ruthenium / molybdenum disulfide photocatalyst.

[0016] Ruthenium salts include soluble salts of ruthenium; the molar ratio of ruthenium salts, molybdenum disulfide and sodium borohydride is (0.001-0.01):(5-7):(0.5-1.0).

[0017] The aging temperature is 20℃-40℃, more preferably 20-30℃, and even more preferably about 25℃; the aging time is 12-36 h, more preferably 16-28 h, and even more preferably about 24 h.

[0018] The ruthenium / molybdenum disulfide photocatalyst contains 0.1-1% ruthenium by mass. Preferably, the ruthenium / molybdenum disulfide photocatalyst contains 0.5% ruthenium by mass, at which point the alanine production rate is faster.

[0019] The voltage of the electrocatalysis is -0.6 V to -1.2 V (relative to the reversible hydrogen electrode, RHE), preferably -0.8 V to -1.1 V, more preferably about -1.0 V, and the electrocatalysis operates for more than 1 h.

[0020] The photocatalytic reaction uses a visible light source, with a preferred light intensity of 250-400 mW / cm². -2 More preferably 300-360 mW cm -2 More preferably, it is about 340 mW cm -2 .

[0021] The photocatalytic reaction is carried out at a temperature of 25-70°C, more preferably 40-60°C, further preferably 45-55°C, and most preferably about 50°C. Within this temperature range, the rates of lactic acid oxidation and subsequent CN coupling reaction are relatively high, which is beneficial to improving the alanine production efficiency.

[0022] Compared with the prior art, the present invention has the following beneficial effects: (1) This invention does not simply improve a certain electrocatalyst or photocatalyst, but constructs a continuous cascade system of “electrocatalytic nitrogen supply - intermediate fixation - hydrolysis release - photocatalytic CN coupling”, realizing the whole process connection of nitrogen-containing intermediates from generation, stabilization to utilization; (2) In view of the problem that hydroxylamine is difficult to accumulate stably in the electrocatalytic system and is easily reduced to ammonia, the present invention improves the availability and transferability of hydroxylamine through an in-situ fixation strategy, creating conditions for its downstream utilization. (3) By hydrolyzing the fixed intermediate to release hydroxylamine after output and delivering it to the photocatalytic system in a continuous or quasi-continuous manner, the instantaneous concentration of hydroxylamine in the photocatalytic system is effectively controlled, reducing volatilization, local side reactions and nitrogen source waste caused by one-time feeding, which is conducive to improving alanine production efficiency and process stability. (4) This invention realizes the coupling of resource-based treatment of nitrate-containing wastewater and high-value conversion of lactic acid, and has the dual functions of pollutant reduction and high-value-added amino acid preparation, and has good prospects for green manufacturing applications.

[0023] The “continuous cascade” in this invention refers to the following: the electrocatalytic nitrogen supply unit, the fixed intermediate output unit, the hydrolysis unit and the photocatalytic synthesis unit are connected sequentially in the process flow, and at least the fixed intermediate or the hydroxylamine solution obtained from its hydrolysis is continuously or quasi-continuously transported to the photocatalytic unit, thereby realizing the continuous generation, continuous release and continuous utilization of nitrogen-containing intermediates.

[0024] The term "quasi-continuous" refers to periodic short-term feeding at set time intervals, which results in a stable and continuous material supply in the overall process.

[0025] The innovation of this invention lies primarily in the construction of the cascade system and the intermediate management strategy, rather than being limited to a specific catalyst material. Specifically, this invention, for the first time, addresses the problem of the unstable accumulation of hydroxylamine during electrocatalytic nitrate reduction by proposing a process design of "in-situ fixation—subsequent hydrolysis release—continuous transport and utilization," and couples this design with the photocatalytic production of alanine from lactic acid to form a continuous cascade production system. This system achieves controlled transfer and efficient utilization of nitrogen-containing intermediates between different reaction units, overcoming the limitations of existing technologies where the nitrogen supply step and CN coupling step are separated, intermediates are difficult to connect, and nitrogen utilization is low. Attached Figure Description

[0026] Figure 1 This is a comparison graph showing the alanine production rate in Comparative Examples 1 and 2 with and without a peristaltic pump.

[0027] Figure 2 This is a comparison chart showing the rate of alanine production via photocatalysis at different temperatures in Comparative Example 3.

[0028] Figure 3 This is a schematic diagram of the photoelectric synergistic driven continuous cascade production device for alanine in this invention, wherein 1 is an electrocatalytic device, 2 is a cathode catalytic electrode, 3 is a counter electrode, 4 is a proton exchange membrane, 5 is a hydrolysis device, 6 is a peristaltic pump, 7 is a ruthenium / molybdenum disulfide photocatalyst, 8 is a magnetic heating stirrer, 9 is a magnetic stirrer, 10 is a photocatalytic reactor, 11 is a visible light source, and 12 is a lactic acid storage device.

[0029] Figure 4 This is a comparison chart of the alanine production rate under the same molar amounts of raw materials in Example 1 and Comparative Example 1.

[0030] Figure 5 This represents the alanine yield over time in Example 1. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Modifications or equivalent substitutions made by those skilled in the art based on their understanding of the technical solutions of this invention, without departing from the spirit and scope of the invention, should be covered within the protection scope of this invention.

[0032] All raw materials used in the following specific embodiments were purchased commercially. The cathode catalytic electrode uses a type of catalyst that facilitates the electrocatalytic synthesis of hydroxylamine from nitrate. Catalysts with this function reported in existing technologies can be used to achieve this, such as those described by Kong, X.; Ni, J.; Song, Z.; Yang, Z.; Zheng, J.; Xu, Z.; Qin, L.; Li, H.; Geng, Z.; Zeng, J. Synthesis of hydroxylamine from air and water via aplasma-electrochemical cascade pathway. Nat. Sustain. 2024, 7 FePC-KB reported in (5), 652-660; Wang, R.; Li, W.; Zheng, C.; Song, X.; Liu, H.; Zhang, L.; Wu, L.;Tan, X.; Ma, X.; Qu, B.; Feng, R.; Li, Q.; Meng, Q.; Jing, L.; J. Am. Chem. Soc. 2025, 147 (51), 47848-47858. reported I-Bi; Tang, Y.; Jiang, Z.; Yuan, Y.; Xu, L.; Jin, C.; Chen, B.; Lin, Z.;Zao, J.; Du, J.; Zhang, X.; Nat. Commun. 2024, 15 (1), ZnPc MDE reported in 9800; Kong, X.; Ni, J.; Song, Z.; Yang, Z.; Zheng, J.; Xu, Z.; Qin, L.; Li, H.; Geng, Z.; Nat. Sustain. 2024, 7 Bi film / CFP, etc., reported in (5), 652-660.

[0033] In this embodiment of the invention, Cu-MnO2H x Taking the catalyst as an example, the prepared catalyst is dispersed on carbon paper to obtain the cathode working electrode, specifically Cu-MnO2H. xThe synthesis method was based on the article “Lattice Hydrogen Involved Electrocatalytic Nitrate Reduction to Hydroxylamine” published in the Journal of the American Chemical Society (J. Am. Chem. Soc. 2025, 147(17): 14869–14877).

[0034] The photocatalyst used is a ruthenium / molybdenum disulfide photocatalyst, and the specific preparation method includes: (1) Preparation of molybdenum disulfide nanosheets: The nanosheets were prepared using a cathodic electrochemical exfoliation method. The specific steps are as follows: A self-made dual-electrode single-chamber electrolytic cell was used, and an electrochemical workstation was employed for control. Mechanically exfoliated 2H-phase molybdenum disulfide (2×2 cm in size) was selected. 2 The molybdenum disulfide crystal (with a purity ≥ 99.995%) was used as the cathode. Before use, the surface of the above molybdenum disulfide crystal was peeled off with tape to remove contaminants, followed by cleaning with acetone and isopropanol in sequence, and drying under a nitrogen atmosphere. The treated molybdenum disulfide crystal was clamped between two titanium foil current collectors to ensure good electrical contact.

[0035] A platinum wire spiral was used as the counter electrode, maintained at a distance of approximately 1.5 cm from the cathode. The electrolyte was prepared by dissolving 250 mg tetrabutylammonium bromide and 10 mg polyvinylpyrrolidone in 50 mL of N,N-dimethylformamide, and bubbling with argon for 15 min to remove dissolved oxygen. Electrochemical exfoliation was performed under static conditions at room temperature with a constant potential of -5 V for 30 min. During exfoliation, tetrabutylammonium ions intercalated into the layered structure, causing crystal expansion, manifested as a volume increase in the material and a change in color from metallic luster to a grayish hue. After the reaction, the resulting dispersion was centrifuged at 4000 rpm for 15 min to remove unexfoliated lumps and excess particles. The supernatant was collected and further purified by three centrifugations (10000 rpm, 10 min), redispersed in fresh N,N-dimethylformamide after each centrifugation to remove residual electrolytes and surfactants. Finally, the product was dispersed in N,N-dimethylformamide to obtain a molybdenum disulfide nanosheet dispersion with a concentration of 20 mg / mL.

[0036] (2) Preparation of ruthenium / molybdenum disulfide photocatalyst: 30 mg of sodium borohydride was added dropwise to 50 mL of the above molybdenum disulfide nanosheet dispersion, and the mixture was stirred at room temperature for 15 min. Subsequently, a solution containing 10.26 mg of ruthenium chloride was added dropwise to the above mixture to make the mass fraction of ruthenium 0.5%. After the addition was complete, the mixture was stirred and aged at 25 °C for 24 h. After the reaction was completed, the precipitate was collected and washed three times each with deionized water and anhydrous ethanol to remove unreacted substances and impurities. Finally, the product was freeze-dried overnight to obtain the ruthenium / molybdenum disulfide photocatalyst.

[0037] Comparative Example 1 Step 1: Disperse 24 mg of ruthenium / molybdenum disulfide photocatalyst and 40 mmol of lactic acid in 8 ml of deionized water by ultrasonication, and turn on the heating device to make the system temperature reach 50°C. Step 2: Turn on the light source; the light intensity is 340 mW / cm². -2 A mixed solution consisting of 8 mL of deionized water and 0.1338 mol of ammonia was continuously pumped into the reaction system at a rate of 0.1 mL / min using a peristaltic pump. Argon gas was continuously introduced during the reaction to maintain an inert atmosphere.

[0038] Comparative Example 2 24 mg of ruthenium / molybdenum disulfide photocatalyst, 40 mmol of lactic acid, and 0.1338 mol of ammonia were ultrasonically dispersed in 16 mL of deionized water. The heating device was turned on, and the light source was activated when the system temperature reached 50°C, with a light intensity of 340 mW / cm². -2 Argon gas was continuously introduced during the reaction to maintain an inert atmosphere. This is a comparison of the alanine production rates in Comparative Example 1 and Comparative Example 2 without using a peristaltic pump. Figure 1 As shown, the alanine production rate increased by more than double after using a peristaltic pump compared to when no peristaltic pump was used, demonstrating a significant effect.

[0039] Comparative Example 3 Following the process conditions of Comparative Example 1, the heating temperatures of the photocatalytic reaction system in step 1 were set to 25℃, 40℃, 60℃, and 70℃, respectively, and the alanine production rate at different heating temperatures was tested. The results are as follows: Figure 2 As shown, the alanine production rate exhibits a volcano-like change with increasing heating temperature, reaching its peak when the heating temperature reaches 50℃.

[0040] Example 1 Adopting such Figure 3The production apparatus shown includes an electrocatalytic nitrogen supply unit, an intermediate hydrolysis unit, and a photocatalytic reaction unit connected in sequence via a pipeline. The nitrogen source is generated by the electrocatalytic nitrogen supply unit and transported to the downstream unit via the intermediate hydrolysis unit in a continuous or quasi-continuous manner.

[0041] In the electrocatalytic power supply unit, a platinum sheet is set as the counter electrode 3 in the electrocatalytic device 1, Cu-MnO2H x The catalyst serves as the working electrode 2, separated by a proton exchange membrane 4. The electrocatalytic nitrogen supply unit operates continuously, generating and fixing hydroxylamine in an electrolyte containing nitrate and a fixative, forming a fixed intermediate that can release hydroxylamine through hydrolysis. This fixed intermediate is continuously introduced into the hydrolysis unit 5 via a first conveying device, where hydroxylamine is released. The resulting hydroxylamine solution is continuously pumped to the photocatalytic reactor 10 at a set flow rate via a peristaltic pump 6. Simultaneously, lactic acid substrate is continuously or pre-added to the photocatalytic reactor via a lactic acid reservoir 12. The photocatalytic reactor 10 is placed on a magnetically heated stirrer 8, where it is stirred and mixed by a magnetic stirrer 9, and the reaction temperature is maintained at 50°C. A visible light source 11 is simultaneously turned on for irradiation, and a photocatalytic reaction occurs under the action of a ruthenium / molybdenum disulfide photocatalyst 7, achieving a continuous cascade reaction to generate alanine.

[0042] Specific steps may include: Step 1: In electrocatalytic device 1, using 0.5 M K₂SO₄ + 0.2 M KNO₃ + 0.2 M acetone as the electrolyte, electrocatalytic reduction of nitrate is carried out under constant voltage. The applied voltage is -1.0 V. vs. The reaction time is at least 1 h. The acetone oxime produced is fed into a hydrolysis device and hydrolyzed to obtain a hydroxylamine solution. The hydroxylamine solution is continuously delivered to a peristaltic pump at a rate of 0.1 mL / min. Step 2: The reaction solution containing ruthenium / molybdenum disulfide photocatalyst and lactic acid was ultrasonically dispersed in 8 mL of deionized water to form a reaction solution. The reaction solution was stirred at 50°C and irradiated with a light intensity of 340 mW / cm². -2 Hydroxylamine solution was continuously pumped into the reaction system using a peristaltic pump, and argon gas was continuously introduced during the reaction to maintain an inert atmosphere, thus producing alanine.

[0043] Similar to Comparative Example 1, ammonia water using a peristaltic pump was used as the raw material. A comparison was made under the same raw material molar ratio. In this example, hydroxylamine was used as the raw material, and the production rate of alanine was as follows: Figure 4 As shown, compared to using ammonia as a raw material, the efficiency of photocatalytic preparation of alanine using hydroxylamine as a raw material is significantly improved.

[0044] As reaction time increases, the yield of alanine decreases as follows: Figure 5As shown, the production of alanine exhibits a linear increasing trend over time.

Claims

1. A photoelectric synergistically driven continuous cascade production method for alanine, characterized in that, The steps include: using an aqueous solution containing nitrate and a fixative as the electrolyte, and electrocatalyzing the formation of a hydroxylamine intermediate under the action of a cathode catalytic electrode; Hydroxylamine intermediate was hydrolyzed to obtain a hydroxylamine solution, which was continuously fed into a solution containing lactic acid and a photocatalyst, and alanine was obtained by photocatalysis. The cathode catalytic electrode contains an electrocatalytic material that promotes the conversion of nitrate ions into hydroxylamine.

2. The photoelectric synergistic driven continuous cascade production method of alanine according to claim 1, characterized in that, The hydroxylamine solution is fed at a rate controlled by a peristaltic pump, with the feed rate being 0.05-1 mL / min.

3. The photoelectric synergistic driven continuous cascade production method of alanine according to claim 1, characterized in that, The fixative includes acetone; The electrocatalytic material includes Cu-MnO2H x Any one of FePC-KB, I-Bi, ZnPc MDE, or Bi film / CFP, where x represents the lattice hydrogen content in the material.

4. The photoelectric synergistic driven continuous cascade production method of alanine according to claim 1, characterized in that, The photocatalyst is any one or more of ruthenium / molybdenum disulfide photocatalyst, ruthenium / cadmium sulfide, cadmium sulfide nanosheets, and cobalt phosphide / cadmium sulfide.

5. The photoelectric synergistic driven continuous cascade production method of alanine according to claim 4, characterized in that, The preparation of the ruthenium / molybdenum disulfide photocatalyst includes the following steps: mixing and stirring ruthenium salt, molybdenum disulfide and sodium borohydride for aging; after the reaction is completed, the product is separated, washed and dried to obtain the ruthenium / molybdenum disulfide photocatalyst.

6. The photoelectric synergistic driven continuous cascade production method of alanine according to claim 5, characterized in that, Ruthenium salts include soluble salts of ruthenium; the molar ratio of ruthenium salts, molybdenum disulfide, and sodium borohydride is (0.001-0.01):(5-7):(0.5-1.0). The aging temperature is 20℃-40℃, and the aging time is 12-36 h.

7. The photoelectric synergistic driven continuous cascade production method of alanine according to claim 5, characterized in that, The ruthenium / molybdenum disulfide photocatalyst contains 0.1-1% ruthenium by mass.

8. The photoelectric synergistic driven continuous cascade production method of alanine according to claim 1, characterized in that, The voltage of the electrocatalysis is -0.6 V to -1.2 V; the operating time of the electrocatalysis is more than 1 h.

9. The photoelectric synergistic driven continuous cascade production method of alanine according to claim 1, characterized in that, The photocatalytic reaction uses a visible light source, with a preferred light intensity of 250-400 mW / cm². -2 .

10. The photoelectric synergistic driven continuous cascade production method of alanine according to claim 1, characterized in that, The temperature for the photocatalytic reaction is 25-70℃.

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