A photocatalyst and a method for preparing amino acids based on photocatalytic nitrogen fixation

Abstract

This invention relates to the field of photocatalysis technology, specifically to a photocatalyst and a method for preparing amino acids based on photocatalytic nitrogen fixation. The chemical formula of the photocatalyst is as follows: Ru y / Mo x Fe3S4; 0.005≤y≤0.06, 0.3≤x≤0.9. This bimetallic modified photocatalyst material has a simple synthesis method, mild reaction conditions, and can efficiently convert substrates into amino acids.

Description

Technical Field

[0001] This invention relates to the field of photocatalysis technology, specifically to a photocatalyst and a method for preparing amino acids based on photocatalytic nitrogen fixation. Background Technology

[0002] Amino acids are zwitterionic structures with an α-carbon atom at their core and containing amino and carboxyl groups. They are the basic building blocks of proteins, playing a crucial role in protein spatial conformation and functional activity, and are of great significance in many fields. Currently, amino acid synthesis faces challenges such as high synthesis costs and strong dependence on raw materials. Therefore, it is necessary to develop efficient and sustainable alternative pathways to construct a closed-loop, low-carbon green synthesis system for amino acids.

[0003] Currently, amino acid synthesis mainly relies on three traditional pathways: bio-fermentation, chemical synthesis, and protein hydrolysis extraction. However, all of these have significant limitations: bio-fermentation, while producing high-purity L-amino acids, is constrained by long strain screening cycles, high energy consumption for product separation, and high costs associated with aseptic operation; chemical synthesis is prone to producing racemic mixtures, uses toxic reagents, and depends on fossil raw materials; and protein hydrolysis extraction is limited by natural protein resources, resulting in low yields and significant energy consumption and wastewater problems. More importantly, these methods largely rely on NH3 or organic amines prepared by the Haber-Bosch process as amination agents. This process requires high temperatures of 300-500℃ and high pressures of 150-300 atm, consuming 1%-2% of global energy annually and generating large carbon emissions, which contradicts the concept of green and low-carbon development and urgently requires more sustainable technological breakthroughs.

[0004] Photocatalysis (PC) technology is based on the principle of driving electron transitions with light energy. It utilizes the band structure of photocatalysts to generate highly active electron-hole pairs, achieving directional substrate transformation under mild conditions. This avoids the dependence on energy-intensive amination agents in traditional processes. In amino acid synthesis, photocatalysis can couple nitrogen fixation and amination. Using N2 as the nitrogen source, under mild conditions of ambient temperature and pressure, the photocatalytic system activates N2 molecules to generate active nitrogen species, simultaneously driving the dehydrogenation of biomass hydroxy acids to form intermediates. These two substances further react to generate amino acids without the need for additional amination agents prepared using the Haber-Bosch process. Furthermore, it can be combined with non-derivative detection techniques for rapid and quantitative reaction of substrates and products, balancing reaction efficiency and environmental friendliness, providing an innovative pathway for the green synthesis of amino acids.

[0005] Different amino acid synthesis technologies have varying limitations. For example, traditional bio-fermentation methods involve long strain screening cycles, high energy consumption for product separation, and stringent requirements for aseptic operation, increasing capital and operating costs. In chemical synthesis, the Strecker method suffers from high catalyst costs, the use of harmful cyanides, and the inability to selectively produce specific enantiomers. The Bucherer-Bergs method is characterized by long reaction times and high temperatures. Protein hydrolysis extraction is only suitable for large-scale production of specific amino acids, relying on naturally abundant protein resources, resulting in low yields and involving high energy consumption and wastewater treatment. Furthermore, existing amination reactions largely depend on non-renewable nitrogen sources such as NH3 or organic amines, requiring high-temperature, high-pressure, and high-energy-consumption Haber-Bosch reaction conditions. Summary of the Invention

[0006] This invention provides a bimetallic modified Fe3S4 photocatalytic material with a simple synthesis method, mild reaction conditions, and efficient conversion of substrates into amino acids.

[0007] This invention first provides a photocatalyst, the chemical formula of which is as follows: Ru y / Mo x Fe3S4; where 0.005≤y≤0.06, 0.3≤x≤0.9.

[0008] In some specific embodiments, the photocatalyst has the chemical formula Ru. 0.015 / Mo 0.45 Fe3S4, Ru 0.005 / Mo 0.3 Fe3S4, Ru 0.005 / Mo 0.9 Fe3S4, Ru 0.01 / Mo 0.9 Fe3S4, Ru 0.015 / Mo 0.9 Fe3S4, Ru 0.03 / Mo 0.9 Fe3S4, Ru 0.03 / Mo 0.45 Fe3S4 or Ru 0.06 / Mo 0.45 Fe3S4.

[0009] Preferably, y is 0.015 and x is 0.45, meaning the chemical formula of the photocatalyst is Ru. 0.015 / Mo 0.45 Fe3S4. Experiments show that it exhibits the best photocatalytic performance for the photocatalytic nitrogen fixation and amino acid preparation.

[0010] The present invention also provides a method for preparing the above-mentioned photocatalyst, comprising: Fe(NO3)3·9H2O and thiourea were dissolved in ethylene glycol (EG) and stirred until homogeneous. Then, an ethylene glycol solution of Na2MoO4 was added (the theoretical molar ratio of Mo to Fe was x), and the mixture was sonicated, heated, and allowed to react. The mixture was then washed and dried to obtain Mo. x Fe3S4; Add RuCl3·3H2O to pure water, and slowly inject sodium borohydride solution through a microsyringe at a uniform rate, stirring until homogeneous; then add the Mo... x Fe3S4 (Ru NP with Mo x The theoretical mass ratio of Fe3S4 is y), ultrasonically homogenized, stirred, and separated (filtered or centrifuged) to obtain a solid product. The product is then washed and dried to obtain the catalyst Ru. y / Mo x Fe3S4.

[0011] Specifically, the preparation method of the photocatalyst includes: dissolving Fe(NO3)3·9H2O and thiourea in ethylene glycol (EG), stirring, adding ethylene glycol containing different amounts of Na2MoO4 to the solution (the theoretical molar ratio of Mo to Fe is x), sonicating and transferring to a polytetrafluoroethylene liner, and heating in an electric drying oven at 180°C for 12 hours. Washing and drying yields Mo. x Fe3S4. Add RuCl3·3H2O to pure water and slowly inject sodium borohydride solution using a microsyringe at a uniform rate. After stirring, add Mo... x Fe3S4 was added to the above solution (Ru NP with Mo x The theoretical mass ratio of Fe3S4 is y). After ultrasonic homogenization and stirring, a solid product is obtained by filtration or centrifugation. After repeated washing and drying overnight, the photocatalyst Ru is obtained. y / Mo x Fe3S4.

[0012] This invention also includes the photocatalyst Ru prepared by the above method. y / Mo x Fe3S4.

[0013] The present invention also includes the above-mentioned photocatalyst Ru y / Mo x Application of Fe3S4 in photocatalytic preparation of amino acids.

[0014] Specifically, in the aforementioned application, the reactants are nitrogen gas and biomass hydroxy acids (such as lactic acid, β-phenyllactic acid, malic acid, etc.).

[0015] The present invention also provides a method for preparing amino acids based on photocatalytic nitrogen fixation, comprising: adding the photocatalyst and biomass hydroxy acids into an aqueous reaction system; introducing N2; and reacting under light conditions to obtain amino acids.

[0016] After the reaction is complete, the catalyst can be removed by centrifugation and membrane filtration to obtain the supernatant, which contains amino acids.

[0017] In some specific embodiments, illumination can be provided by a 350W xenon lamp.

[0018] In some specific embodiments, N2 is introduced under dark conditions to achieve N2 adsorption-desorption equilibrium.

[0019] In some specific embodiments, a sandwiched quartz photoreactor is used as the reaction vessel.

[0020] In some specific embodiments, the reaction time is 1-6 h; the reaction temperature is 50-100 °C; the reaction pH is 2.25-13; and the amount of lactic acid substrate is 0.05-0.2 mol / L.

[0021] In some specific embodiments, the method for preparing amino acids based on photocatalytic nitrogen fixation includes:

[0022] The photocatalyst and biomass hydroxy acid were added to an aqueous reaction system and placed in a 150mL sandwich quartz photoreactor equipped with a 350W xenon lamp. N2 was introduced under dark conditions to reach N2 adsorption-desorption equilibrium. After the reaction was completed, the catalyst was removed by centrifugation and membrane filtration to obtain the supernatant.

[0023] This invention utilizes a high-performance liquid chromatography system with methanol-potassium phosphate aqueous solution as the mobile phase to achieve simultaneous quantification of substrate and product.

[0024] This invention utilizes a photocatalytic system to activate the coupling reaction between N2 and biomass hydroxy acids, which can efficiently convert lactic acid into alanine at room temperature and pressure. The lactic acid conversion rate reaches 69.1%, the selectivity for alanine reaches 74.3%, and it has good applicability to a variety of substrates such as β-phenyllactic acid and malic acid.

[0025] This invention prepares a bimetallic modified Fe3S4 photocatalytic material that combines excellent light absorption performance with high charge separation efficiency, enabling the activation of N2 and biomass hydroxy acids under mild conditions. This invention also establishes a green synthetic method for photocatalytic nitrogen fixation and coupling amination, which can use N2 as a nitrogen source and biomass hydroxy acids as a carbon source to generate amino acids at low cost and high efficiency under relatively low temperature and ambient pressure.

[0026] This invention uses biomass hydroxy acids as raw materials, relies on photocatalysis technology, and constructs a Ru / Mo bimetallic photocatalyst to achieve a coupling reaction of photocatalytic nitrogen fixation and amination of biomass hydroxy acids under normal pressure and relatively low temperature conditions. It utilizes readily available N2 as the nitrogen source, with photogenerated carriers activating N2 to generate... The active intermediate condenses and reduces biomass hydroxy acids to generate amino acids. Under optimized conditions, lactic acid can be efficiently converted into alanine. Furthermore, this system has substrate universality for various biomass hydroxy acids, such as β-phenyllactic acid (containing a benzene ring side chain) and malic acid (a dicarboxylic acid structure), demonstrating its potential for promoting the high-value utilization of other biomass derivatives. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of existing amino acid preparation methods; where a) is the preparation of amino acids by enzymatic hydrolysis or fermentation; b) is the preparation of amino acids by photocatalysis using ammonia water obtained from industrial (high temperature and high pressure) nitrogen fixation as raw material; and c) is the preparation of amino acids by thermocatalysis under high temperature and high pressure.

[0028] Figure 2 This is a schematic diagram of the synthesis apparatus used for photocatalytic nitrogen fixation to prepare amino acids in an embodiment of the present invention.

[0029] Figure 3 The figures show the results of photocatalytic nitrogen fixation for amino acid preparation in an embodiment of the present invention; wherein, a) the effect of catalyst composite ratio on catalytic performance; b) the effect of reaction pH on amino acid yield; c) the effect of temperature on amino acid yield; and d) the effect of different lactic acid concentrations on substrate utilization and amino acid yield.

[0030] Figure 4 This is a graph showing the effect of different exogenous acids on the regulation of lactic acid conversion in Experiment 2 of this invention.

[0031] Figure 5 These are characterization and reusability diagrams of the photocatalysts in embodiments of the present invention.

[0032] Figure 6 This is a graph showing the substrate versatility of the photocatalyst in this invention for converting different biomass hydroxy acids into corresponding amino acids.

[0033] Figure 7 a) is 14 N2 and 15 (a) ATR-FTIR superposition of the products of amination reaction catalyzed by N2 red as a nitrogen source; (b) is the reaction solution for isotope experiments. 1 H-NMR spectrum.

[0034] Figure 8a is a schematic diagram of the preparation method of the photocatalyst in the embodiment of the present invention; b and c are scanning electron microscope (SEM) images of the photocatalyst in the embodiment of the present invention; d is an EDX surface scan result of the photocatalyst in the embodiment of the present invention.

[0035] Figure 9 This is the XRD pattern of the photocatalyst in an embodiment of the present invention.

[0036] Figure 10 This is the FT-IR spectrum of the photocatalyst in an embodiment of the present invention. Detailed Implementation

[0037] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described in detail below. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0038] Chinese-English bilingual

[0039]

[0040] Figure 1 This is a schematic diagram of several existing methods for preparing amino acids. Figure 2 This is a schematic diagram of the synthesis apparatus used for photocatalytic nitrogen fixation to prepare amino acids in an embodiment of the present invention.

[0041] Example 1

[0042] 1.21 g Fe(NO3)3·9H2O and 0.46 g thiourea were dissolved in 59 mL of ethylene glycol and magnetically stirred to form a yellowish-brown solution. Then, 1 mL of ethylene glycol containing a different amount of Na2MoO4 (the theoretical molar ratio of Mo to Fe is x) was added. After mixing and sonicating for 20 min, the mixture was heated in an electric drying oven at 180 °C for 12 hours. After the reaction was completed and cooled, the solid product was centrifuged and dried in a vacuum oven at 60 °C for 4 hours to obtain black Mo. x Fe3S4; Add a certain amount of RuCl3·3H2O to 50mL of pure water, and inject 20mL of solution containing 14.7mg sodium borohydride through a microsyringe over 20 minutes. Stir for more than 24 hours, and then add a certain amount of Mo. x Fe3S4 (Ru NP with Mo x (The theoretical mass ratio of Fe3S4 is y). The mixture was ultrasonically homogenized for at least 12 hours, centrifuged to obtain a solid product, and then washed several times alternately with deionized water and ethanol. After vacuum drying at 60°C overnight, the photocatalyst was obtained, with the chemical structural formula Ru. y / Mo xFe3S4.

[0043] By controlling the amounts of Na2MoO4 and RuCl3·3H2O added, the following eight photocatalysts were obtained: Ru 0.015 / Mo 0.45 Fe3S4, Ru 0.005 / Mo 0.3 Fe3S4, Ru 0.005 / Mo 0.9 Fe3S4, Ru 0.01 / Mo 0.9 Fe3S4, Ru 0.015 / Mo 0.9 Fe3S4, Ru 0.03 / Mo 0.9 Fe3S4, Ru 0.03 / Mo 0.45 Fe3S4, Ru 0.06 / Mo 0.45 Fe3S4.

[0044] Comparative Example 1

[0045] 1.21 g Fe(NO3)3·9H2O and 0.46 g thiourea were dissolved in 60 mL ethylene glycol. After ultrasonic stirring to form a yellowish-brown solution, the solution was transferred to a stainless steel autoclave lined with tetrafluoroethylene and heated in an electric drying oven at 180 °C for 12 hours. After the autoclave cooled naturally to room temperature, the suspension was centrifuged at 8000 r / min for 5 minutes. The solid was washed several times with ethanol and distilled water, and then dried in a vacuum oven at 60 °C for 4 hours and ground to obtain a powdered photocatalyst, namely Fe3S4.

[0046] Experiment 1

[0047] The catalytic performance of the nine photocatalysts prepared in Example 1 and Comparative Example 1 was tested respectively.

[0048] Each catalyst (25 mg) was dispersed in 100 mL of deionized water containing 5 mmol of lactic acid, and photocatalytic amination was carried out under the conditions of nitrogen flow rate of 0.1 L / min, 70 °C, and irradiation by a 350 W xenon lamp for 4 h (the apparatus used is as follows). Figure 2 As shown in the figure, the alanine yield was determined by high-performance liquid chromatography (HPLC), and the effect of the catalyst composite ratio on the catalytic performance was investigated. The results are as follows. Figure 3 As shown in Figure a. The results indicate that among the nine catalysts tested with different Mo doping ratios (10, 15, 30 mol%) and Ru loadings (0.5, 1, 1.5, 3, 6 wt%), when the Mo doping content is 45 mol% and the Ru loading is 1.5 wt%, i.e., Ru... 0.015 / Mo 0.45Fe3S4 exhibits the best catalytic performance, achieving an alanine yield of 1.127 g / L.

[0049] catalyst Ru 0.015 / Mo 0.45 The test results for Fe3S4 are shown in Table 1.

[0050]

[0051] In Experiment 1, the optimal catalyst Ru was used. 0.015 / Mo 0.45 In the Fe3S4 system, the effect of pH on the yield of alanine was investigated by adjusting the initial reaction pH with exogenous acids and bases. The results are as follows: Figure 3 As shown in b, the pH of the system naturally increased during the reaction, rising from an initial 2.25 to 5.51 after 6 hours of reaction, indicating that the reaction consumed h... + When the initial pH is gradually adjusted from 3.0 to 9.0, OH... - Promoting lactic acid ionization (lactic acid pKa ≈ 3.86) increased alanine production from a lower level to a peak of 1.662 g / L; however, when the pH continued to rise to 13, alanine production decreased sharply due to excess OH-. - The destruction of the Fe3S4 crystal structure leads to catalyst deactivation; therefore, the initial pH of 9.0 was determined to be the optimal condition.

[0052] In the best catalyst Ru 0.015 / Mo 0.45 Under Fe3S4 and initial pH=9.0 conditions, and with monitoring of alanine production at different temperatures, the results are as follows: Figure 3 As shown in Figure c: Within 3 hours of reaction, high temperature accelerates mass transfer and substrate activation, and the alanine yield reaches 1.773 g / L at 100℃; however, after extending the reaction to 6 hours, due to side reactions induced by high temperature (such as alanine decarboxylation), the alanine concentration in the system at 100℃ decreased by 22.33%; while at 90℃, the alanine concentration only decreased from 4.4545 g / L to 4.3592 g / L, a decrease of only 2.14%. Therefore, the optimal parameters were selected as a reaction temperature of 90℃ and a reaction time of 4 hours.

[0053] Under the above optimal conditions, the lactic acid concentration was adjusted to 0.02~0.2 mol / L to investigate the effect of lactic acid concentration. The results are as follows: Figure 3As shown in d, the overall performance was optimal when the lactic acid concentration was 0.05 mol / L, with a lactic acid conversion rate of 69.1%, alanine selectivity of 74.3%, and a yield of 2.9028 g / L. As the concentration increased to 0.15 mol / L, the conversion rate decreased from 74.3% to 50.2% (a decrease of 24.1%), and the selectivity also decreased. This was because high concentrations of lactic acid excessively occupied the active sites of the catalyst, inhibiting the binding of N2-activated intermediates to the substrate. Therefore, a lactic acid concentration of 0.05 mol / L was determined to be the optimal substrate concentration.

[0054] Experiment 2

[0055] By constructing different exogenous acid systems (1 a Hydrochloric acid, 2 b Citric acid, 3 c Lactic acid-free, 4 d No N2, 5 e (Investigating the effect of introducing air) on the conversion of lactic acid to alanine, with Ru as the catalyst. 0.015 / Mo 0.45 Fe3S4, method as described in Experiment 1. Results are shown below. Figure 4 The results showed that citric acid (an organic acid) had the best regulatory effect, increasing alanine yield to 2.28 g / L and selectivity to 69.1%. 1 H-NMR confirmed that citric acid restricts side reactions through deprotonation, stabilizes active sites, and promotes CN coupling. Combined with Table 1, it can be seen that control experiments without lactic acid, without N2, and with air introduced respectively demonstrate that lactic acid is an essential substrate, N2 is a necessary nitrogen source, and O2 has an inhibitory effect on amination efficiency.

[0056] Experiment 3

[0057] This experiment tested the bimetallic modified iron sulfide-based catalyst Ru of the present invention. 0.015 / Mo 0.45 N2 adsorption-desorption isotherms and reusability (Cycles) of Fe3S4, bimetallic modified Ru x / Mo y Fe3S4BET has a specific surface area of ​​46.97 m² / g, an average pore size of 9.85 nm, and a pore volume of 0.1256 cm³ / g (e.g., ...). Figure 5 (a). After four cycles, although the yield of lactic acid to alanine catalyzed by this catalyst decreased slightly, it still maintained more than 90% of the initial yield (e.g., ...). Figure 5 (b) Combined with ICP-MS detection, after 4 cycles, the leaching rates of Mo and Ru were 3.96% and 2.71%, respectively, with only a small amount of metal loss. This indicates that the bimetallic modified photocatalyst material in this study possesses good structural characteristics and cycling stability, and has practical application potential.

[0058] Experiment 4

[0059] In the bimetallic modified photocatalytic material Ru of this invention 0.015 / Mo 0.45 The substrate universality test of Fe3S4 for different biomass hydroxy acids revealed (e.g.) Figure 6 Under the same conditions, this material can catalyze the conversion of various biomass hydroxy acids into their corresponding amino acids, but the yield varies depending on the substrate structure. Among them, the highest yield was achieved for the conversion of α-hydroxybutyric acid to α-aminobutyric acid, reaching 2.21 mmol·g⁻¹. cat -1 ·h -1 Overall, this indicates that the bimetallic modified photocatalytic material has the ability to convert various biomass hydroxy acids and has a certain degree of substrate universality.

[0060] Subsequently, ATR-FTIR and ¹H-NMR were used to... 14 N2 and 15 The products of the catalytic amination reaction using N2 as a nitrogen source were characterized by isotopic labeling, such as... Figure 7 As shown in the ATR-FTIR spectral overlay, with 15 When N2 is used as the nitrogen source, the product is at ~3235 cm⁻¹. -1 The NH vibration peak at ~1390 cm⁻¹ -1 The CN vibration peak at that location, compared to 14 Characteristic shifts were observed in all N2 groups, confirming that the N atoms in the nitrogen-containing functional groups originated from exogenous N2, and the presence of these shifts was also detected. 15 N x H y The characteristic peaks of the intermediate indicate that N2 is photocatalytically reduced to reactive nitrogen species. 1 In the H-NMR spectrum 15 The chemical shifts of alanine α-H (δ≈3.73ppm) and β-CH3 (δ≈1.41ppm) in the N2 group products were compared with... 14 Group N2 shifted slightly towards higher fields, and 15 The coupling constant (J=7.0Hz) between N and the adjacent H is different. 14 N (J=7.2Hz) further verified at the molecular level that the N atom in alanine directly originates from the N2 used in the reaction, eliminating interference from external nitrogen sources and clarifying "N2→*N". x H y The reaction pathway is "→imine→amino acid".

[0061] Experiment 5

[0062] In Example 1, a series of Ruy / MoxFe3S4 catalysts with different Mo doping amounts (10, 15, 30 mol%, denoted as the Mo / Fe atomic molar ratio x) and Ru loading amounts (0.5, 1, 1.5, 3, 6 wt%, denoted as the Ru / MoxFe3S4 mass ratio y) were successfully constructed from a molybdenum-doped, ruthenium-supported iron tetrasulfide composite material prepared by a solvothermal method. The synthesis process is shown in […]. Figure 8 a. Scanning electron microscopy (SEM) analysis showed that ( Figure 8 (b and c), compared to bare Fe3S4 microspheres, Ru 0.015 / Mo 0.45 More abundant lamellar structures grew on the Fe3S4 surface, forming an irregular flower-like morphology. (EDX surface scan results) Figure 8 (d) confirms that Ru, Mo, Fe, and S elements are uniformly distributed in the material.

[0063] XRD patterns ( Figure 9 The FT-IR spectrum shows that the characteristic diffraction peaks of the prepared Fe3S4 are highly consistent with those of the cubic phase standard card (PDF#16-0713), corresponding to the (220), (311), (222), (400), (422), (511), (440), and (533) crystal planes, indicating the successful synthesis of high-purity Fe3S4. After the introduction of Mo and Ru, the intensity of the characteristic peaks of Fe3S4 decreased, and the full width at half maximum (FWHM) increased (ΔFWHM=0.13-0.88°), indicating a decrease in the proportion of crystalline phases and a decrease in crystallinity. No crystalline diffraction peaks of Ru or Mo were observed, attributed to their low loading and amorphous dispersion. Figure 10 ) at 600-700cm -1 The presence of characteristic peaks for Fe-S bending vibration and SS stretching vibration in the range is consistent with the reported Fe3S4 band in the literature, further confirming the successful synthesis of the sulfide.

[0064] Although the present invention has been described in detail above with general descriptions, specific embodiments, and experiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A photocatalyst, characterized in that, Its chemical formula is as follows: Ru y / Mo x Fe3S4 Where 0.005≤y≤0.06, 0.3≤x≤0.

9.

2. The photocatalyst according to claim 1, characterized in that, The chemical formula of the photocatalyst is Ru 0.015 / Mo 0.45 Fe3S4, Ru 0.005 / Mo 0.3 Fe3S4, Ru 0.005 / Mo 0.9 Fe3S4, Ru 0.01 / Mo 0.9 Fe3S4, Ru 0.015 / Mo 0.9 Fe3S4, Ru 0.03 / Mo 0.9 Fe3S4, Ru 0.03 / Mo 0.45 Fe3S4 or Ru 0.06 / Mo 0.45 Fe3S4 3. The method for preparing the photocatalyst according to claim 1 or 2, characterized in that, include: Fe(NO3)3·9H2O and thiourea were dissolved in ethylene glycol and stirred until homogeneous. Then, an ethylene glycol solution of Na2MoO4 was added, and the mixture was sonicated, heated, and allowed to react. The mixture was then washed and dried to obtain Mo. x Fe3S4; Add RuCl3·3H2O to pure water, and slowly inject sodium borohydride solution using a microsyringe, stirring until homogeneous; then add the Mo... x Fe3S4 was ultrasonically homogenized, stirred, and separated to obtain a solid product. The product was then washed and dried to obtain the catalyst Ru. y / Mo x Fe3S4.

4. The photocatalyst prepared by the method of claim 3.

5. The photocatalyst Ru according to claim 1, 2 or 4 y / Mo x Application of Fe3S4 in photocatalytic preparation of amino acids.

6. The application according to claim 5, characterized in that, In this application, the reactants are nitrogen gas and biomass hydroxy acids.

7. A method for preparing amino acids based on photocatalytic nitrogen fixation, characterized in that, include: The photocatalyst and biomass hydroxy acids are added to an aqueous reaction system; Introduce N2; The reaction is carried out under light conditions to obtain amino acids.

8. The method according to claim 7, characterized in that, The reaction time is 1-6 hours; the reaction temperature is 50-100℃; the reaction pH is 2.25-13; and the amount of lactic acid substrate used is 0.05-0.2 mol / L.

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