Electrocatalyst based on Cu-Zn metal organic framework material as well as preparation method and application of electrocatalyst

Abstract

The invention relates to the technical field of electrocatalysts, in particular to an electrocatalyst based on a Cu-Zn metal organic framework material and a preparation method and application of the electrocatalyst. According to the preparation method, firstly, a precursor HKUST-1-Cux-Zny MOFs is synthesized, and the precursor HKUST-1-Cux-Zny MOFs is converted into a hollow Cu-Zn metal organic framework material in situ through ligand exchange; compared with a traditional synthetic method of an organic metal framework material, the metal organic framework material obtained through a ligand exchange in-situ conversion method has a hollow structure, so that the metal organic framework material has a larger specific surface area, and more catalytic active sites can be exposed. Meanwhile, due to the unique structure and electronic characteristics of the Cu-Zn metal organic framework material, the problems of low selectivity, low Faraday efficiency (FE) and low yield during existing electrocatalytic synthesis of amino acid are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of electrocatalysts, and in particular to an electrocatalyst based on a Cu-Zn metal organic framework material and a preparation method and application thereof. Background Art

[0002] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention, and should not necessarily be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art.

[0003] Amino acids are a class of amphiphilic organic compounds containing alkaline amino groups and acidic carboxyl groups. They are the basic building blocks of biological functional macromolecule proteins. Amino acids play an important role in life, including the synthesis of neurotransmitters, hormones and nucleotides. In addition, amino acids have many potential uses, such as: as an additive for animal feed, a flavoring agent, a biochemical reagent, a pharmaceutical agent and a cosmetic.

[0004] Currently, amino acids are mainly produced through microbial fermentation processes and protein hydrolysis, which can produce 20 amino acids that make up proteins, but the production efficiency is low. In addition, the fermentation process has potential problems such as strict requirements for aseptic operation conditions, long time consumption, high energy consumption of microbial culture, and complex product separation and purification processes. Other chemical synthesis methods, including Strecker synthesis, Erlenmeyer-Plochl reaction, and Bucherer-Bergs reaction, provide more efficient synthesis methods. However, these methods usually rely on the use of toxic compounds such as hydrogen cyanide (HCN) and ammonium cyanide (NH4CN), as well as non-renewable ammonia, which poses great challenges to large-scale and sustainable production. Therefore, there is an urgent need to develop cost-effective and efficient amino acid synthesis technologies to overcome these limitations.

[0005] The electrocatalytic synthesis of amino acids can overcome the above shortcomings. Unlike the traditional method of synthesizing amino acids, there has been no research in the field of electrocatalytic synthesis of amino acids, and the applied electrocatalysts have rarely been reported. Summary of the invention

[0006] In order to overcome the above problems, the present invention provides an electrocatalyst based on a Cu-Zn metal organic framework material and a preparation method and application thereof.

[0007] In order to achieve the above technical objectives, the present invention adopts the following technical solutions:

[0008] The first aspect of the present invention provides a Cu-Zn metal organic framework material, the structural formula of which is shown in Formula I, Formula II or Formula III:

[0009]

[0010]

[0011] The second aspect of the present invention provides a method for preparing the above-mentioned Cu-Zn metal organic framework material, comprising:

[0012] (1) Dissolving trimesic acid (H3BTC) in an alkaline solution to obtain a BTC alkaline solution; mixing a copper salt solution, a zinc salt solution, and a BTC alkaline solution to obtain a mixed salt solution; and adding the mixed salt solution to a sodium salt solution to react and obtain HKUST-1-Cu, a precursor of a Cu-Zn metal organic framework material. x -Zn y MOFs;

[0013] (2) HKUST-1-Cu x -Zn y MOFs are dispersed in a solvent, organic ligands are added thereto, and ligand exchange occurs by stirring to obtain a Cu-Zn metal organic framework material;

[0014] When the organic ligand is benzene hexathiol (BHT), a Cu-Zn metal organic framework material shown in formula I is obtained;

[0015] When the organic ligand is 1,3,5-triamino-2,4,6-benzenetriol (TABTO), a Cu-Zn metal organic framework material shown in formula II is obtained;

[0016] When the organic ligand is hexaaminobenzene hydrochloride (HAB), a Cu-Zn metal organic framework material represented by formula III is obtained.

[0017] The third aspect of the present invention provides the use of the above-mentioned Cu-Zn metal organic framework material as an electrocatalyst for catalytic synthesis of amino acids.

[0018] A fourth aspect of the present invention provides a method for synthesizing amino acids, using the Cu-Zn metal organic framework material as an electrocatalyst to catalyze the synthesis of amino acids from a carbon source and a nitrogen source.

[0019] The beneficial effects of the present invention are:

[0020] (1) In the present invention, the precursor HKUST-1-Cu x -Zn yMOFs are converted in situ into hollow Cu-Zn metal organic framework materials through ligand exchange. Compared with the traditional synthesis method of metal organic framework materials, the metal organic framework material obtained by the in situ conversion method of ligand exchange has a hollow structure, and therefore has a larger specific surface area and can expose more catalytic active sites. At the same time, due to the unique structure and electronic properties of Cu-Zn metal organic framework materials, the problems of low selectivity, low Faraday efficiency (FE) and low yield in the existing electrocatalytic synthesis of amino acids are solved. The experimental results show that the BHT-Cu9-Zn1 synthesized in the embodiment of the present invention can maintain more than 80% FE for up to 240 hours, showing excellent stability.

[0021] (2) The Cu-Zn metal organic framework material provided by the present invention has successfully synthesized 10 essential amino acids: leucine, alanine, valine, phenylalanine, methylalanine, norvaline, glycine, tryptophan, homophenylalanine and cyclobutylglycine.

[0022] (3) The Cu-Zn metal organic framework material provided by the present invention has a simple preparation process, is economical and practical, does not require special equipment and harsh conditions, has practical value, and is easy to mass produce. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0024] Figure 1 XRD test results of BHT-Cu9-Zn1, TABTO-Cu9-Zn1 and HAB-Cu9-Zn1 prepared in Examples 1, 2 and 3;

[0025] Figure 2 (a) TEM, (b) SEM, (c) HRTEM and (d) HADDF images of BHT-Cu9-Zn1 prepared in Example 1;

[0026] Figure 3 Linear sweep voltammetry (LSV) curves of BHT-Cu9-Zn1, TABTO-Cu9-Zn1 and HAB-Cu9-Zn1 prepared in Examples 1, 2 and 3;

[0027] Figure 4 The nuclear magnetic resonance (NMR) spectrum of leucine after 2 hours of BHT-Cu9-Zn1 reaction and the structural formula of the starting material, intermediate product and final leucine;

[0028] Figure 5Potential-dependent Faradaic efficiency (FE) of electrolytic nitrate reduction to leucine by BHT-Cu9-Zn1, TABTO-Cu9-Zn1 and HAB-Cu9-Zn1 in a flow cell;

[0029] Figure 6 Potential-dependent Faradaic efficiency of BHT-Cu9-Zn1 for leucine in the flow cell (a) and the best Faradaic efficiency observed at -1.0 V (b);

[0030] Figure 7 The optimized Faradaic efficiency of BHT-Cu9-Zn1 for different amino acids in the flow cell (a), the photo of synthesized leucine (b), and the structural formula of each amino acid (c). DETAILED DESCRIPTION

[0031] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0032] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0033] A first typical embodiment of the present invention provides a Cu-Zn metal organic framework material, whose structural formula is shown in Formula I, Formula II or Formula III: A Cu-Zn metal organic framework material, whose structural formula is shown in Formula I, Formula II or Formula III:

[0034]

[0035] A second typical embodiment of the present invention provides a method for preparing the above-mentioned Cu-Zn metal organic framework material, comprising:

[0036] (1) Dissolving trimesic acid (H3BTC) in an alkaline solution to obtain a BTC alkaline solution; mixing a copper salt solution, a zinc salt solution, and a BTC alkaline solution to obtain a mixed salt solution; and adding the mixed salt solution to a sodium salt solution to react and obtain HKUST-1-Cu, a precursor of a Cu-Zn metal organic framework material. x -Zn y MOFs;

[0037] (2) HKUST-1-Cu x -Zny MOFs are dispersed in a solvent, organic ligands are added thereto, and ligand exchange occurs by stirring to obtain a Cu-Zn metal organic framework material;

[0038] When the organic ligand is benzene hexathiol (BHT), a Cu-Zn metal organic framework material shown in formula I is obtained;

[0039] When the organic ligand is 1,3,5-triamino-2,4,6-benzenetriol (TABTO), a Cu-Zn metal organic framework material shown in formula II is obtained;

[0040] When the organic ligand is hexaaminobenzene hydrochloride (HAB), a Cu-Zn metal organic framework material represented by formula III is obtained.

[0041] In one or more embodiments, in step (1), the alkali solution includes one or more of sodium hydroxide solution, ammonia, methylamine, ethylamine and triethylamine, preferably triethylamine.

[0042] In one or more embodiments, in step (1), the molar ratio of trimesic acid to the alkaline substance in the alkali solution is 1:5-10, preferably 1:7.2.

[0043] In one or more embodiments, in step (1), the concentration of BTC in the BTC alkaline solution is 0.008 to 0.012 mol / L, preferably 0.01 mol / L.

[0044] In one or more embodiments, in step (1), the sodium salt includes one or more of sodium chloride, sodium carbonate, sodium bicarbonate, sodium nitrate, sodium sulfate, and sodium acetate, preferably sodium nitrate.

[0045] In one or more embodiments, in step (1), the solvent of the sodium salt solution includes one or more of water, acetone, acetonitrile, N,N-dimethylformamide, N,N-dimethylacetamide, ethanol, methanol or N-methylpyrrolidone, preferably a water / ethanol mixed solvent;

[0046] More preferably, the volume ratio of water to ethanol is 4-6:6-4, preferably 1:1.

[0047] In one or more embodiments, in step (1), the concentration of the sodium salt solution is 0.04-0.06 mol / L, preferably 0.05 mol / L.

[0048] In one or more embodiments, in step (1), the copper salt includes one or more of cuprous iodide, cuprous chloride, cuprous nitrate, cuprous bromide, cupric iodide, cupric chloride, cupric nitrate, and cupric bromide, preferably cupric nitrate.

[0049] In one or more embodiments, in step (1), the concentration of the copper salt solution is 0.08-0.1 mol / L, preferably 0.09 mol / L.

[0050] In one or more embodiments, in step (1), the zinc salt includes one or more of zinc gluconate, zinc sulfate, zinc chloride, zinc nitrate, and zinc acetate, preferably zinc nitrate.

[0051] In one or more embodiments, in step (1), the concentration of the zinc salt is 0.008 to 0.012 mol / L, preferably 0.01 mol / L.

[0052] In one or more embodiments, in step (1), the molar ratio of sodium salt, copper salt, zinc salt to BTC base in BTC base solution is: 60-90:1.2-1.5:0.12-0.18:0.8-1.2, preferably 75:1.35:0.15:1.

[0053] In one or more embodiments, in step (1), the stirring reaction time is 2 to 10 minutes, preferably 5 minutes.

[0054] In one or more embodiments, in step (2), the solvent includes one or more of water, acetone, acetonitrile, N,N-dimethylformamide, N,N-dimethylacetamide, ethanol, methanol or N-methylpyrrolidone, preferably a water / methanol mixed solvent;

[0055] More preferably, the volume ratio of water to methanol is 4-6:6-4, preferably 1:1.

[0056] In one or more embodiments, in step (2), HKUST-1-Cu x -Zn y The mass ratio of MOFs to organic ligands is 1 to 4:1, preferably 2:1.

[0057] In one or more embodiments, in step (2), the stirring reaction time is 0.5 to 2 hours, preferably 1 hour.

[0058] A third typical embodiment of the present invention provides the use of the above-mentioned Cu-Zn metal organic framework material as an electrocatalyst for catalyzing the synthesis of amino acids.

[0059] A fourth aspect of the present invention provides a method for synthesizing amino acids, using the Cu-Zn metal organic framework material as an electrocatalyst to catalyze the synthesis of amino acids from a carbon source and a nitrogen source.

[0060] In one or more embodiments, the carbon source includes: α-keto acid; the α-keto acid includes: α-ketoisocaproic acid, pyruvic acid, α-ketoisovaleric acid, phenylpyruvic acid, α-ketoisobutyric acid, α-ketovaleric acid, aminoacetic acid, indole-3-pyruvic acid, α-ketocaproic acid, and cyclobutylpyruvic acid.

[0061] In one or more embodiments, the nitrogen source comprises nitrate.

[0062] In one or more embodiments, the synthetic amino acids include leucine, alanine, valine, phenylalanine, methylalanine, norvaline, glycine, tryptophan, homophenylalanine, and cyclobutylglycine.

[0063] In order to enable those skilled in the art to more clearly understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below in conjunction with specific embodiments.

[0064] Example 1

[0065] (1) 2.1 g (0.01 mol) of H3BTC was dissolved in 10 mL of triethylamine solution and dried to obtain BTC triethylammonium salt. The dried BTC triethylammonium salt was dissolved in distilled water to form a 0.1 M BTC triethylammonium solution. 6.375 g of NaNO3 was dissolved in 1500 mL of a 1:1 (v / v) mixture of ethanol and water to prepare a 0.05 M NaNO3 solution. 15 mL of a mixed aqueous solution of 0.09 M Cu(NO3)2·3H2O and 0.01 M Zn(NO3)2·3H2O was mixed with 10 mL of 0.1 M BTC triethylammonium solution. The mixture was added dropwise to the NaNO3 solution under vigorous stirring. After reacting at room temperature for 5 minutes, the blue HKUST-1 solid was collected by filtration, washed with ethanol and water, and dried at 90°C to obtain the HKUST-1-Cu9-Zn1 nanoparticles shown in Formula IV.

[0066]

[0067] (2) 10 mg of the synthesized HKUST-1-Cu9-Zn1 was dispersed in 5 mL of a 1:1 (v / v) mixed solution of methanol / water to form a light blue solution. 5 mg of benzene hexathiol (BHT) dissolved in 3 mL of methanol was added to the above solution. The reaction was stirred at room temperature for 1 hour. The obtained dark purple precipitate was filtered, washed with water and acetone, and vacuum dried at 90°C overnight to obtain hollow BHT-Cu9-Zn1 nanocubes, i.e., the Cu-Zn metal organic framework material shown in Formula I.

[0068] Example 2

[0069] (1) 2.1 g (0.01 mol) H3BTC was dissolved in 10 mL triethylamine solution and dried to obtain BTC triethylammonium salt. The dried BTC triethylammonium salt was dissolved in distilled water to form a 0.1 M BTC triethylammonium solution. 6.375 g NaNO3 was dissolved in 1500 mL 1:1 (v / v) ethanol and water mixture to prepare a 0.05 M NaNO3 solution. 15 mL of a mixed aqueous solution of 0.09 M Cu(NO3)2·3H2O and 0.01 M Zn(NO3)2·3H2O was mixed with 10 mL 0.1 M BTC triethylammonium solution. The mixture was added dropwise to the NaNO3 solution under vigorous stirring. After reacting at room temperature for 5 minutes, the blue HKUST-1 solid was collected by filtration, washed with ethanol and water, and dried at 90 °C to obtain HKUST-1-Cu9-Zn1 nanoparticles.

[0070] (2) Disperse 10 mg of synthesized HKUST-1-Cu9-Zn1 in 5 mL of methanol / water = 1:1 (v / v) mixed solution to form a light blue solution. Add 5 mg of 1,3,5-triamino-2,4,6-benzenetriol (TABTO) dissolved in 3 mL of methanol to the above solution. Stir the reaction at room temperature for 1 hour. Filter the resulting dark purple precipitate, wash with water and acetone, and vacuum dry overnight at 90°C to obtain hollow TABTO-Cu9-Zn1 nanocubes, i.e., the Cu-Zn metal organic framework material shown in Formula II.

[0071] Example 3

[0072] (1) 2.1 g (0.01 mol) H3BTC was dissolved in 10 mL triethylamine solution and dried to obtain BTC triethylammonium salt. The dried BTC triethylammonium salt was dissolved in distilled water to form a 0.1 M BTC triethylammonium solution. 6.375 g NaNO3 was dissolved in 1500 mL 1:1 (v / v) ethanol and water mixture to prepare a 0.05 M NaNO3 solution. 15 mL of a mixed aqueous solution of 0.09 M Cu(NO3)2·3H2O and 0.01 M Zn(NO3)2·3H2O was mixed with 10 mL 0.1 M BTC triethylammonium solution. The mixture was added dropwise to the NaNO3 solution under vigorous stirring. After reacting at room temperature for 5 minutes, the blue HKUST-1 solid was collected by filtration, washed with ethanol and water, and dried at 90 °C to obtain HKUST-1-Cu9-Zn1 nanoparticles.

[0073] (2) 10 mg of the synthesized HKUST-1-Cu9-Zn1 was dispersed in 5 mL of a methanol / water = 1:1 (v / v) mixed solution to form a light blue solution. 5 mg of hexaaminobenzene hydrochloride (HAB) dissolved in 3 mL of methanol was added to the above solution. The reaction was stirred at room temperature for 1 hour. The obtained dark purple precipitate was filtered, washed with water and acetone, and vacuum dried at 90°C overnight to obtain hollow HAB-Cu9-Zn1 nanocubes, i.e., the Cu-Zn metal organic framework material shown in Formula III.

[0074] Figure 1 The XRD test results of BHT-Cu9-Zn1, TABTO-Cu9-Zn1 and HAB-Cu9-Zn1 prepared in Examples 1, 2 and 3 show that the synthesized MOFs have phase purity and high crystallinity. The presence of unique peaks for each MOF highlights their different crystal planes, which are directly related to their catalytic performance and stability.

[0075] Figure 2 Transmission electron microscope (TEM) image of BHT-Cu9-Zn1 prepared in Example 1 ( Figure 2 a) shows that the hollow nanocubes have uniform morphology and size, with a lateral length of 400-500 nm. This hierarchical hollow structure is crucial for improving catalytic performance because it provides a large surface area and facilitates efficient mass transfer. Scanning electron microscopy (SEM) image ( Figure 2 b) illustrates the surface morphology, showing a clear texture structure. High-resolution TEM (HRTEM) image ( Figure 2 c) shows the lattice fringes with a spacing of 0.33 nm, corresponding to the 001 crystal plane, indicating high crystallinity at the atomic scale. Finally, the high-angle annular dark field (HAADF) image ( Figure 2 d) The uniform distribution of Cu and Zn within the nanocubes is confirmed, which is crucial for improving the catalytic performance.

[0076] Example 4

[0077] The electrocatalyst obtained in Example 3 was used to test the electrolytic reduction of nitrate to amino acids. A standard three-electrode system was used in the electrolytic cell, with a carbon rod as the counter electrode and a mercury / mercurous sulfate electrode as the reference electrode. The test was carried out in nitrate (0.1 M) and α-keto acid (0.2 M) solutions.

[0078] Figure 3The linear sweep voltammetry (LSV) curves of BHT-Cu9-Zn1, TABTO-Cu9-Zn1 and HAB-Cu9-Zn1 prepared in Examples 1, 2 and 3 are used to test the electrochemical activity of MOF. BHT-Cu9-Zn1 exhibits the highest current density among the test materials, indicating that it has the most active sites for electrocatalytic reactions. This superior activity shows that BHT-Cu9-Zn1 is very suitable for amino acid synthesis, superior to TABTO-Cu9-Zn1 and HAB-Cu9-Zn1. This is because higher current density is associated with better electron transfer ability and more efficient catalytic performance.

[0079] Figure 4 The nuclear magnetic resonance (NMR) spectrum of leucine after 2 hours of BHT-Cu9-Zn1 reaction and the structural formula of the starting material, intermediates and final leucine. The spectrum shows not only leucine, but also intermediates and some unreacted starting monomers. This indicates that there is a reaction pathway involving intermediates before leucine is fully formed. The identification of intermediates helps to understand the reaction mechanism and optimize conditions to obtain higher yields of the desired amino acid.

[0080] Figure 5 Potential-dependent Faradaic efficiency (FE) of electrolytic nitrate reduction to leucine for BHT-Cu9-Zn1, TABTO-Cu9-Zn1, and HAB-Cu9-Zn1 in a flow cell. BHT-Cu9-Zn1 with Cu-S / Zn-S active sites showed the best performance with a FE of over 80%. In contrast, TABTO-Cu9-Zn1 and HAB-Cu9-Zn1 had lower FEs of approximately 40% and 50%, respectively. The specific BHT-Cu9-Zn1 structure was more effective for amino acid production compared to the other two MOFs, and this difference demonstrates that the active site composition plays a key role in the catalytic efficiency of the material.

[0081] Figure 6 a is the potential-dependent Faradaic efficiency of leucine in a flow cell with BHT-Cu9-Zn1. The best Faradaic efficiency was observed at -1.0 V, indicating that this potential is most suitable for producing leucine in a continuous flow system. This finding is crucial for scaling up the process and applying it to practical industrial applications. Figure 6 b shows the potential-dependent Faradaic efficiency (FE) and stability of BHT-Cu9-Zn1 for electrocatalytic production of leucine at -1.0 V relative to RHE. The data show that BHT-Cu9-Zn1 can maintain more than 80% FE for up to 240 h, showing excellent stability.

[0082] Figure 7The optimized Faradaic efficiency (FE) of BHT-Cu9-Zn1 for different amino acids in the flow cell is shown, including leucine, alanine, valine, phenylalanine, methylalanine, norvaline, glycine, tryptophan, homophenylalanine, and cyclobutylglycine, in descending order. Leucine has the highest FE, while cyclobutylglycine has the lowest FE, close to 40%. This comparison shows that BHT-Cu9-Zn1 can be widely used to synthesize a variety of essential amino acids with significant efficiency, especially highlighting its effectiveness for those amino acids that are more difficult to produce.

[0083] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A Cu-Zn metal organic framework material, characterized in that: Its structural formula is shown in Formula I, Formula II or Formula III:

2. The method for preparing the Cu-Zn metal organic framework material according to claim 1, characterized in that: include: (1) dissolving trimesic acid (H3BTC) in an alkali solution to obtain a BTC alkali solution; The copper salt solution, zinc salt solution and BTC alkaline solution are mixed to obtain a mixed salt solution, and the mixed salt solution is added to the sodium salt solution to react to obtain the precursor of the Cu-Zn metal organic framework material HKUST-1-Cu x -Zn y MOFs; (2) HKUST-1-Cu x -Zn y MOFs are dispersed in a solvent, organic ligands are added thereto, and ligand exchange occurs by stirring to obtain a Cu-Zn metal organic framework material; When the organic ligand is benzene hexathiol (BHT), a Cu-Zn metal organic framework material shown in formula I is obtained; When the organic ligand is 1,3,5-triamino-2,4,6-benzenetriol (TABTO), a Cu-Zn metal organic framework material shown in formula II is obtained; When the organic ligand is hexaaminobenzene hydrochloride (HAB), a Cu-Zn metal organic framework material represented by formula III is obtained.

3. The preparation method according to claim 2, characterized in that: In step (1), the alkali solution includes one or more of sodium hydroxide solution, ammonia methylamine, ethylamine and triethylamine, preferably triethylamine; Or, in step (1), the molar ratio of trimesic acid to the alkaline substance in the alkali solution is 1:5-10, preferably 1:7.2; Alternatively, in step (1), the concentration of BTC in the BTC solution is 0.008 to 0.012 mol / L, preferably 0.01 mol / L.

4. The preparation method according to claim 2, characterized in that: In step (1), the sodium salt includes one or more of sodium chloride, sodium carbonate, sodium bicarbonate, sodium nitrate, sodium sulfate, and sodium acetate, preferably sodium nitrate; Or, in step (1), the solvent of the sodium salt solution includes one or more of water, acetone, acetonitrile, N,N-dimethylformamide, N,N-dimethylacetamide, ethanol, methanol or N-methylpyrrolidone, preferably a water / ethanol mixed solvent; further preferably, the volume ratio of water to ethanol is 4-6:6-4, preferably 1:1; Alternatively, in step (1), the concentration of the sodium salt solution is 0.04-0.06 mol / L, preferably 0.05 mol / L.

5. The preparation method according to claim 2, characterized in that: In step (1), the copper salt includes one or more of cuprous iodide, cuprous chloride, cuprous nitrate, cuprous bromide, cupric iodide, cupric chloride, cupric nitrate, and cupric bromide, preferably cupric nitrate; Or, in step (1), the concentration of the copper salt solution is 0.08-0.1 mol / L, preferably 0.09 mol / L; Or, in step (1), the zinc salt includes one or more of zinc gluconate, zinc sulfate, zinc chloride, zinc nitrate, and zinc acetate, preferably zinc nitrate; Or, in step (1), the concentration of the zinc salt is 0.008-0.012 mol / L, preferably 0.01 mol / L.

6. The preparation method according to claim 2, characterized in that: In step (1), the molar ratio of sodium salt, copper salt, zinc salt to BTC base in BTC base solution is: 60-90:1.2-1.5:0.12-0.18:0.8-1.2, preferably 75:1.35:0.15:1; Alternatively, in step (1), the stirring reaction time is 2 to 10 minutes, preferably 5 minutes.

7. The preparation method according to claim 2, characterized in that: In step (2), the solvent includes one or more of water, acetone, acetonitrile, N,N-dimethylformamide, N,N-dimethylacetamide, ethanol, methanol or N-methylpyrrolidone, preferably a water / methanol mixed solvent; further preferably, the volume ratio of water to methanol is 4-6:6-4, preferably 1:1; Or, in step (2), HKUST-1-Cu x -Zn y The mass ratio of MOFs to organic ligands is 1 to 4:1, preferably 2:1; Alternatively, in step (2), the stirring reaction time is 0.5 to 2 h, preferably 1 h.

8. Use of the Cu-Zn metal organic framework material according to claim 1 and / or the Cu-Zn metal organic framework material prepared by the preparation method according to any one of claims 2 to 7 as an electrocatalyst for catalytic synthesis of amino acids.

9. A method for synthesizing an amino acid, characterized in that: The Cu-Zn metal organic framework material according to claim 1 and / or the Cu-Zn metal organic framework material prepared by the preparation method according to any one of claims 2 to 7 is used as an electrocatalyst to catalyze the synthesis of amino acids from carbon sources and nitrogen sources.

10. The synthesis method according to claim 9, characterized in that The carbon source includes: the α-keto acid includes: α-ketoisocaproic acid, pyruvic acid, α-ketoisovaleric acid, phenylpyruvic acid, α-ketoisobutyric acid, α-ketovaleric acid, aminoacetic acid, indole-3-pyruvic acid, α-ketocaproic acid, cyclobutylpyruvic acid; or, the nitrogen source comprises nitrate; Alternatively, synthetic amino acids include leucine, alanine, valine, phenylalanine, methylalanine, norvaline, glycine, tryptophan, homophenylalanine, and cyclobutylglycine.

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