Method for synthesizing glycine through electrocatalysis of oxalic acid and nitrate
By loading the electrode material with a two-dimensional PbSnS2 catalyst and regulating the electron transfer path, the problem of over-reduction of oxalic acid and nitrate during the electrosynthesis of glycine was solved, the reaction efficiency and selectivity were improved, the energy consumption was reduced, and efficient and economical glycine production was achieved.
Patent Information
- Application Number
- CN202510842939.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-23
- Publication Date
- 2025-09-05
AI Technical Summary
In the existing technology, oxalic acid and nitrate are easily over-reduced during the electrosynthesis of glycine, resulting in reduced reaction selectivity and Faradaic efficiency, as well as safety risks and high energy consumption.
By using an electrode material loaded with a two-dimensional PbSnS2 catalyst, the electron transfer pathway is synergistically regulated by sulfur vacancies and metal sites, the activation energy of the C=O and NO bonds is reduced, and the CN coupling selectivity is promoted. A mixed solution of oxalic acid and potassium nitrate is electrolyzed at a constant current density to produce glycine.
The reaction efficiency is improved, energy consumption is reduced, safety risks are reduced, and the production process is simplified, achieving more economical and efficient glycine production.
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Figure CN120591797A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of materials and electrocatalysis, and in particular to a method for electrocatalytically synthesizing glycine from oxalic acid and nitrate. Background Art
[0002] α-Amino acids are the fundamental building blocks of proteins and important biomolecules in living systems. They form polypeptide chains and proteins through peptide bond polymerization and have extensive applications in drug development, food technology, and materials science. Traditional amino acid synthesis methods, such as the Strecker method, often involve the use of highly toxic cyanide and suffer from poor solubility. Enzymatic hydrolysis, while offering advantages such as short reaction times and ease of operation, is often limited by temperature and pH. Hydrolysis requires high-temperature, high-pressure equipment and high operating costs. Glycine, as the simplest amino acid, is widely used in daily life. Compared to traditional amino acid synthesis methods, electrochemical synthesis of glycine offers advantages such as simple process, mild reaction conditions, and high product quality. The ideal electrosynthesis method for glycine is a one-step electrolytic synthesis, but the CN coupling process involves multiple electron transfers, resulting in the production of multiple byproducts and competition from the hydrogen evolution reaction. Therefore, achieving high selectivity and high Faradaic efficiency for electrosynthesis of glycine is a significant challenge.
[0003] The most commonly used carbon sources for the electrosynthesis of amino acids are biomass-derived acids, such as pyruvate, glyoxylate, and 2-ketopentanoate. However, these often require high costs, hindering their industrial application. Selecting carbon-based molecules upstream of keto acids offers a strong competitive advantage in reducing electrosynthesis costs and promoting industrial implementation. The co-reduction of oxalic acid and nitrate primarily involves two half-reactions: the electroreduction of oxalic acid and the electroreduction of nitrate. Oxalic acid can be directly obtained by CO2 electroreduction. Previous studies have demonstrated that CO2 electroreduction to oxalic acid can achieve a Faradaic efficiency exceeding 80% at high current densities. Using nitrate from wastewater as a nitrogen source, the intermediate hydroxylamine produced during the electroreduction of nitrate has a strong nucleophilic nitrogen atom, while the intermediate glyoxylic acid, generated by the one-step reduction of oxalic acid, has a highly electronegative carbonyl carbon. Hydroxylamine can undergo nucleophilic addition to the carbonyl group of glyoxylic acid to form the key glyoxylic acid oxime precursor, which is further reduced to glycine. During the reaction, both oxalic acid and nitrate are easily over-reduced to generate glycolic acid and ammonium ions, respectively, which reduces the selectivity and Faradaic efficiency of the reaction. Summary of the Invention
[0004] In view of the problems existing in the prior art, the present invention provides a method for synthesizing glycine from oxalic acid and nitrate by electrocatalysis. The present invention uses a metal active material as an anode, an electrode material loaded with a two-dimensional PbSnS2 catalyst as a working electrode, a mixed solution of oxalic acid solution and potassium nitrate solution as an electrolyte solution, an inert gas is continuously introduced into the electrolyte solution, and electrolysis is performed at a constant current density to obtain glycine. The preparation method of the present invention solves the problem of transition reduction of oxalic acid and nitrate by introducing a two-dimensional PbSnS2 catalyst. At the same time, the present invention not only improves reaction efficiency, reduces reaction energy consumption, reduces safety risks, but also simplifies the production process, thereby providing a technical reference for achieving more economical and efficient glycine production.
[0005] In order to achieve the above object, the technical solution adopted by the present invention is: A first object of the present invention is to provide a method for electrocatalytically synthesizing glycine from oxalic acid and nitrate, comprising the following steps: The electrode material loaded with two-dimensional PbSnS2 catalyst is used as the working electrode, and a three-electrode system is composed of a working electrode, a reference electrode and a counter electrode. A mixed solution composed of oxalic acid solution and potassium nitrate solution is used as the electrolyte solution. One end of the three-electrode system is immersed in the electrolyte solution, and the other end is electrically connected to the electrochemical workstation; an inert gas is continuously introduced into the electrolyte solution, and the electrolyte solution is electrolyzed at a constant current density. During the electrolysis process, the sulfur vacancies and metal sites of the two-dimensional PbSnS2 catalyst synergistically regulate the electron transfer path, reduce the activation energy of the C=O and NO bonds, promote the CN coupling selectivity, and obtain glycine.
[0006] Preferably, in the electrolyte solution, the concentrations of the oxalic acid solution and the potassium nitrate solution are both 0.25 mol / L, and the volume ratio of the oxalic acid solution to the potassium nitrate solution is 1:1.
[0007] Preferably, the solvents of the oxalic acid solution and the potassium nitrate solution are both H2SO4, and the concentration of H2SO4 is 1 mol / L.
[0008] Preferably, the electrolysis conditions are: at room temperature, 100 mA / cm 2 ~250mA / cm 2 Electrolysis was carried out for 3h~8h under the conditions of
[0009] Preferably, in the electrode material loaded with the two-dimensional PbSnS2 catalyst, the loading amount of the two-dimensional PbSnS2 catalyst is 1.5 mg / cm 2 ~2.5mg / cm 2 .
[0010] Preferably, the electrode material loaded with a two-dimensional PbSnS2 catalyst is prepared according to the following steps: The two-dimensional PbSnS2 catalyst, a binder and a solvent are mixed to obtain a slurry, which is then coated on carbon paper and dried.
[0011] Preferably, the two-dimensional PbSnS2 catalyst is prepared according to the following steps: Lead, tin and sulfur are mixed and calcined to obtain PbSnS2 crystals; the PbSnS2 crystals are ultrasonically exfoliated in a solvent, filtered and dried to obtain a two-dimensional PbSnS2 catalyst.
[0012] Preferably, when preparing the two-dimensional PbSnS2 catalyst, the molar ratio of lead element, tin element and sulfur element is 1:2:1.
[0013] Preferably, the calcination treatment conditions are: under sealed conditions, at 800°C to 900°C and a vacuum degree of less than 10 -4 Calcination under Pa conditions for 1 to 2 days.
[0014] Preferably, the peeling treatment is performed under ultrasonication at room temperature for 3 to 5 hours.
[0015] Compared with the prior art, the present invention has the following beneficial effects: 0. The present invention provides a method for electrocatalytically synthesizing glycine from oxalic acid and nitrate, comprising: using an electrode material loaded with a two-dimensional PbSnS2 catalyst as a working electrode; a three-electrode system consisting of a working electrode, a reference electrode, and a counter electrode; and a mixed solution of oxalic acid solution and potassium nitrate solution as an electrolyte solution. One end of the three-electrode system is immersed in the electrolyte solution, and the other end is electrically connected to an electrochemical workstation. An inert gas is continuously introduced into the electrolyte solution, and the electrolyte solution is electrolyzed at a constant current density to obtain glycine. The present invention introduces a two-dimensional PbSnS2 catalyst. During the electrolysis process, the sulfur vacancies and metal sites of the two-dimensional PbSnS2 catalyst synergistically regulate the electron transfer pathway, reduce the activation energy of the C=O and N-O bonds, and promote CN coupling selectivity. This not only improves reaction efficiency, reduces reaction energy consumption, and reduces safety risks, but also simplifies the production process, thereby providing a technical reference for achieving more economical and efficient glycine production and solving the problem of excessive reduction of oxalic acid and nitrate.
[0016] 2. In this invention, systematic experiments are used to prove that the scheme of using two-dimensional PbSnS2 catalyst to couple oxalic acid with nitrate to electrosynthesize glycine is feasible and has good stability. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Figure 1 The figure is a schematic diagram of the structure of the device for electrocatalyzing the synthesis of glycine from oxalic acid and nitrate according to the present invention.
[0018] Figure 2XRD patterns of PbSnS2 crystals and two-dimensional PbSnS2 catalysts in the present invention.
[0019] Figure 3 This is a Faraday efficiency performance diagram of the electrocatalytic synthesis of glycine from oxalic acid and nitrate in Examples 1 to 4 of the present invention.
[0020] Figure 4 This is a concentration-time dependence diagram of the electrocatalytic synthesis of glycine from oxalic acid and nitrate in Example 2 of the present invention.
[0021] Figure 5 This is a diagram showing the cyclic stability of the electrocatalytic synthesis of glycine from oxalic acid and nitrate in Example 2 of the present invention. DETAILED DESCRIPTION
[0022] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the data in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.
[0023] It should be noted that the professional terms used in the present invention are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention. Unless otherwise specified, the various raw materials, reagents, instruments and equipment used in the following embodiments of the present invention can be purchased from the market or prepared by existing methods. Among them, the electrochemical workstation is a Shanghai Chenhua CHI 760E electrochemical workstation.
[0024] Currently, in the process of preparing glycine by electroreduction of oxalic acid and nitrate, oxalic acid and nitrate are easily over-reduced to glycolic acid and ammonium ions, which reduces the selectivity and Faradaic efficiency of the reaction.
[0025] In response to the problems existing in the above-mentioned prior art, the present invention provides a method for electrocatalytically synthesizing glycine from oxalic acid and nitrate, comprising the following steps: using an electrode material loaded with a two-dimensional PbSnS2 catalyst as a working electrode, adopting a working electrode, a reference electrode and a counter electrode to form a three-electrode system, using a mixed solution composed of oxalic acid solution and potassium nitrate solution as an electrolyte solution, immersing one end of the three-electrode system in the electrolyte solution, and electrically connecting the other end to an electrochemical workstation; continuously introducing an inert gas into the electrolyte solution, and electrolyzing the electrolyte solution at a constant current density. During the electrolysis process, the sulfur vacancies and metal sites of the two-dimensional PbSnS2 catalyst synergistically regulate the electron transfer path, reduce the activation energy of the C=O and NO bonds, promote the CN coupling selectivity, and obtain glycine.
[0026] In response to the problem in the prior art that oxalic acid and nitrate ions are easily over-reduced to glycolic acid and ammonium ions, resulting in reduced reaction selectivity and Faradaic efficiency, the present invention overcomes this problem by synergistically regulating the electron transfer pathway through the sulfur vacancies and metal sites of the two-dimensional PbSnS2 catalyst, reducing the activation energy of the C=O and NO bonds, and promoting CN coupling selectivity.
[0027] Specifically, during the electrolysis process, oxalic acid is electroreduced to glyoxylic acid on the cathode surface, and nitrate is simultaneously reduced to form a hydroxylamine intermediate; the carbonyl carbon of glyoxylic acid undergoes a nucleophilic addition reaction with the amino group of hydroxylamine to form glyoxylic acid oxime, which is further electroreduced and deoxygenated to form glycine; and the atomic-level thin layer structure of the two-dimensional PbSnS2 has a double-sided exposed surface characteristic. Compared with the bulk material, its active site density is significantly improved, and its sulfur vacancies and metal sites synergistically regulate the electron transfer path, reduce the activation energy of the C=O and NO bonds, promote CN coupling selectivity, and inhibit the excessive reduction of oxalic acid to glycolic acid and the excessive reduction of nitrate to ammonium, thereby realizing the efficient electrosynthesis of glycine.
[0028] 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 with reference to specific embodiments.
[0029] The specific synthesis method of the electrode material loaded with the two-dimensional PbSnS2 catalyst in the embodiment of the present invention is chemical vapor transport (CVT), and the preparation is as follows: Method 1: S1. Weigh 0.2374 g of tin and 0.1282 g of sulfur at a molar ratio of 1:2, respectively. Use iodine as a transfer agent, and weigh 55 mg of iodine at a mass ratio of 20:3 between the mixed powder of tin and sulfur and the iodine.
[0030] Tin, sulfur and iodine were ground in a mortar, mixed evenly and then transferred into a quartz tube and vacuumed to 10 -4 The quartz tube was sealed after Pa; then the quartz tube was placed in a tube furnace, heated to 800°C at a heating rate of 5°C / min and calcined for 24 hours; after the reaction was completed, it was naturally cooled to room temperature to obtain PbSnS2 crystals.
[0031] S2. Immerse the PbSnS2 crystal in an isopropanol solution and ultrasonically treat it in an ultrasonic cleaner for 5 hours to obtain a two-dimensional PbSnS2 catalyst.
[0032] S3. Soak the carbon paper in acetone to remove the organic matter on the surface and set aside. Disperse 5 mg of the two-dimensional PbSnS2 catalyst in a mixture of 600 µL, 0.5 wt% Nafion, 200 µL ethanol and 200 µL deionized water and ultrasonicate for 30 min to obtain a slurry. Then, spray 1 mL of the slurry evenly on a 1 cm 2 ×1cm 2 On the carbon paper, an electrode material loaded with two-dimensional PbSnS2 catalyst was obtained.
[0033] The loading amount of the two-dimensional PbSnS2 catalyst in the electrode material is 2.5 mg / cm 2 .
[0034] Method 2: The preparation method is the same as that of method 1, except that the ultrasonic treatment time of S2 is replaced from 5 h to 3 h.
[0035] Method 3: The preparation method is the same as that of method 1, except that the amount of S3 two-dimensional PbSnS2 catalyst is replaced from 5 mg to 3 mg.
[0036] The loading amount of the two-dimensional PbSnS2 catalyst in the electrode material is 1.5 mg / cm 2 .
[0037] Depend on Figure 1 It was found that the XRD peak positions of the PbSnS2 crystal and the two-dimensional PbSnS2 catalyst in the present invention fully matched the standard comparison chart, which preliminarily proved that the prepared two-dimensional PbSnS2 catalyst had high purity and good cleanliness.
[0038] 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 with reference to specific examples, wherein the electrode materials loaded with two-dimensional PbSnS2 catalysts in Examples 1 to 4 are all prepared by Method 1.
[0039] In Examples 1 to 4 of the present invention, the electrocatalytic method for synthesizing glycine from oxalic acid and nitrate is as follows: Figure 2 As shown, the reaction site is an H-type double electrolytic cell, and the cathode chamber and the anode chamber of the electrolytic cell are separated by a proton exchange membrane (Nafion-117).
[0040] Example 1 A method for electrocatalytically synthesizing glycine from oxalic acid and nitrate, comprising the following steps: S1. A calomel electrode is used as a reference electrode, a platinum sheet is used as a counter electrode, and an electrode material loaded with a two-dimensional PbSnS2 catalyst is used as a working electrode, which are assembled together into a three-electrode system.
[0041] The electrolyte solution used in the cathode chamber is a mixed solution of equal volumes of 0.25 mol / L oxalic acid and 0.25 mol / L potassium nitrate dissolved in 8 mL of 1 mol / L H2SO4, and the electrolyte solution used in the anode chamber is 8 mL of 1 mol / L H2SO4 solution.
[0042] S2. Place the working electrode in the cathode chamber and the counter electrode in the anode chamber, and introduce argon gas into the cathode chamber at a flow rate of 5 mL / min to prevent air interference. At the same time, mechanically stir the electrolyte solution at a speed of 500 rpm.
[0043] Subsequently, the assembled three-electrode system was electrically connected to an electrochemical workstation, and electrolysis was performed at a current density of 100 mA / cm for 5 h to obtain glycine.
[0044] Example 2 A method for electrocatalytically synthesizing glycine from oxalic acid and nitrate, comprising the following steps: S1. A calomel electrode is used as a reference electrode, a platinum sheet is used as a counter electrode, and an electrode material loaded with a two-dimensional PbSnS2 catalyst is used as a working electrode, which are assembled together into a three-electrode system.
[0045] The electrolyte solution used in the cathode chamber is a mixed solution of equal volumes of 0.25 mol / L oxalic acid and 0.25 mol / L potassium nitrate dissolved in 8 mL of 1 mol / L H2SO4, and the electrolyte solution used in the anode chamber is 8 mL of 1 mol / L H2SO4 solution.
[0046] S2. Place the working electrode in the cathode chamber and the counter electrode in the anode chamber, and introduce argon gas into the cathode chamber at a flow rate of 5 mL / min to prevent air interference. At the same time, mechanically stir the electrolyte solution at a speed of 500 rpm.
[0047] Subsequently, the assembled three-electrode system was electrically connected to an electrochemical workstation and electrolysis was performed at a current density of 150 mA / cm for 5 h to obtain glycine.
[0048] Example 3 A method for electrocatalytically synthesizing glycine from oxalic acid and nitrate, comprising the following steps: S1. A calomel electrode is used as a reference electrode, a platinum sheet is used as a counter electrode, and an electrode material loaded with a two-dimensional PbSnS2 catalyst is used as a working electrode, which are assembled together into a three-electrode system.
[0049] The electrolyte solution used in the cathode chamber is a mixed solution of equal volumes of 0.25 mol / L oxalic acid and 0.25 mol / L potassium nitrate dissolved in 8 mL of 1 mol / L H2SO4, and the electrolyte solution used in the anode chamber is 8 mL of 1 mol / L H2SO4 solution.
[0050] S2. Place the working electrode in the cathode chamber and the counter electrode in the anode chamber, and introduce argon gas into the cathode chamber at a flow rate of 5 mL / min to prevent air interference. At the same time, mechanically stir the electrolyte solution at a speed of 500 rpm.
[0051] Subsequently, the assembled three-electrode system was electrically connected to an electrochemical workstation, and electrolysis was performed at a current density of 200 mA / cm for 5 h to obtain glycine.
[0052] Example 4 A method for electrocatalytically synthesizing glycine from oxalic acid and nitrate, comprising the following steps: S1. A calomel electrode is used as a reference electrode, a platinum sheet is used as a counter electrode, and an electrode material loaded with a two-dimensional PbSnS2 catalyst is used as a working electrode, which are assembled together into a three-electrode system.
[0053] The electrolyte solution used in the cathode chamber is a mixed solution of equal volumes of 0.25 mol / L oxalic acid and 0.25 mol / L potassium nitrate dissolved in 8 mL of 1 mol / L H2SO4, and the electrolyte solution used in the anode chamber is 8 mL of 1 mol / L H2SO4 solution.
[0054] S2. Place the working electrode in the cathode chamber and the counter electrode in the anode chamber, and introduce argon gas into the cathode chamber at a flow rate of 5 mL / min to prevent air interference. At the same time, mechanically stir the electrolyte solution at a speed of 500 rpm.
[0055] Subsequently, the assembled three-electrode system was electrically connected to an electrochemical workstation and electrolysis was performed at a current density of 250 mA / cm for 5 h to obtain glycine.
[0056] Depend on Figure 3 It was found that the Faradaic efficiency of glycine could reach 63.35% at a current density of 150 mA / cm, corresponding to a yield of 90.55 mmol / h / g. cat At a current density of 250 mA / cm, the Faradaic efficiency of glycine can still reach 53%, with a yield of 126.19 mmol / h / g. cat , which is better than previous studies.
[0057] observe Figure 4The results showed that after 1 hour of electrolysis at a current density of 100 mA / cm, glyoxylic acid accounted for a high proportion of the cathode solution, with almost no glycine produced. As the reaction proceeded, glyoxylic acid (GC) accumulated, reacting with the nitrogen-reduced intermediate hydroxylamine, increasing the concentration of glyoxylic acid oxime (GX). At 4 hours of reaction, the concentration of glycine increased significantly, while glycolic acid (GAO) and glyoxylic acid oxime were consumed with no significant increase.
[0058] Figure 5 This is a cyclic stability test of the two-dimensional PbSnS2 catalyst in the present invention for the electrocatalytic coupling reaction of oxalic acid and nitrate to produce glycine. Each test is 5 hours, and the cumulative cycle is 8 times. Figure 5 It was concluded that the electrocatalytic performance of the two-dimensional PbSnS2 catalyst did not decrease and showed good stability.
[0059] It should be noted that when the present invention involves numerical ranges, it should be understood that both endpoints of each numerical range and any value between the two endpoints can be selected. Since the steps and methods used are the same as those in the embodiments, in order to avoid redundancy, the present invention describes preferred embodiments. Although preferred embodiments of the present invention have been described, those skilled in the art will be able to make additional changes and modifications to these embodiments once they understand the basic inventive concepts. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.
Claims
1. A method for electrocatalytic synthesis of glycine from oxalic acid and nitrate, characterized in that: The following steps are involved: The electrode material loaded with two-dimensional PbSnS2 catalyst is used as the working electrode, and a three-electrode system is composed of a working electrode, a reference electrode and a counter electrode. A mixed solution composed of oxalic acid solution and potassium nitrate solution is used as the electrolyte solution. One end of the three-electrode system is immersed in the electrolyte solution, and the other end is electrically connected to the electrochemical workstation; an inert gas is continuously introduced into the electrolyte solution, and the electrolyte solution is electrolyzed at a constant current density. During the electrolysis process, the sulfur vacancies and metal sites of the two-dimensional PbSnS2 catalyst synergistically regulate the electron transfer path, reduce the activation energy of the C=O and NO bonds, promote the CN coupling selectivity, and obtain glycine.
2. The method for electrocatalytic synthesis of glycine from oxalic acid and nitrate according to claim 1, characterized in that: The electrolysis conditions were: room temperature, 100 mA / cm 2 ~250mA / cm 2 Electrolysis was carried out for 3h~8h under the conditions of 3. The method for electrocatalytic synthesis of glycine from oxalic acid and nitrate according to claim 1, characterized in that: In the electrode material loaded with two-dimensional PbSnS2 catalyst, the loading amount of two-dimensional PbSnS2 catalyst is 1.5 mg / cm 2 ~2.5mg / cm 2 .
4. The method for electrocatalytic synthesis of glycine from oxalic acid and nitrate according to claim 1, characterized in that: The electrode material loaded with two-dimensional PbSnS2 catalyst was prepared according to the following steps: The two-dimensional PbSnS2 catalyst, a binder and a solvent are mixed to obtain a slurry, which is then coated on carbon paper and dried.
5. The method for electrocatalytic synthesis of glycine from oxalic acid and nitrate according to claim 1, characterized in that: In the electrolyte solution, the concentrations of the oxalic acid solution and the potassium nitrate solution are both 0.25 mol / L, and the volume ratio of the oxalic acid solution to the potassium nitrate solution is 1:
1.
6. The method for electrocatalytic synthesis of glycine from oxalic acid and nitrate according to claim 1, characterized in that: The two-dimensional PbSnS2 catalyst was prepared according to the following steps: Lead, tin and sulfur are mixed and calcined to obtain PbSnS2 crystals; The PbSnS2 crystals were subjected to ultrasonic exfoliation in a solvent, and then filtered and dried to obtain a two-dimensional PbSnS2 catalyst.
7. The method for electrocatalytic synthesis of glycine from oxalic acid and nitrate according to claim 6, characterized in that: The molar ratio of lead element, tin element and sulfur element is 1:2:
1.
8. The method for electrocatalytic synthesis of glycine from oxalic acid and nitrate according to claim 6, characterized in that: The calcination treatment conditions are: under sealed conditions, at 800℃~900℃ and vacuum degree less than 10 -4 Calcination under Pa conditions for 1 to 2 days.
9. The method for electrocatalytic synthesis of glycine from oxalic acid and nitrate according to claim 6, characterized in that: The peeling treatment conditions are: ultrasonic treatment at room temperature for 3h~5h.