A catalyst for preparing glycolic acid by selective oxidation of ethylene glycol and a preparation method thereof

Abstract

The application belongs to the technical field of electrocatalytic synthesis and nanomaterials, and particularly relates to a catalyst for preparing glycolic acid by selective oxidation of ethylene glycol and a preparation method thereof.The catalyst has a multi-stage composite structure: taking a nickel-based metal organic framework as a precursor, high-temperature thermal reduction and carbonization are performed to reconstruct a carbon nanotube conductive substrate loaded with nickel nanoparticle tips; on this basis, cobalt phthalocyanine molecules with clear active centers are loaded by a non-covalent bonding mode. By regulating the substituent structure around the cobalt phthalocyanine molecules, the selectivity of the catalyst to the ethylene glycol oxidation path can be finely adjusted, and efficient directional conversion of the glycolic acid product can be realized. The catalyst completely uses non-noble metals, has the advantages of high activity, excellent selectivity, good stability and low cost; the preparation process is simple and controllable, and has good reproducibility, thereby providing an efficient and reliable catalyst solution for green electrocatalytic value-added conversion of ethylene glycol.

Description

Technical Field

[0001] This invention belongs to the field of electrocatalytic synthesis and nanomaterials technology, specifically relating to a catalyst for the selective oxidation of ethylene glycol to prepare glycolic acid and its preparation method. Background Technology

[0002] Electrocatalytic synthesis, which uses renewable electricity to drive the directional conversion of organic molecules into high-value-added chemicals, has become a cutting-edge direction in the fields of green chemistry and sustainable energy. This technology can achieve oxidation reactions that require high temperature, high pressure, and toxic oxidants (such as potassium permanganate and nitric acid) in traditional thermocatalysis under mild conditions (normal temperature and pressure) using water as an oxygen source. It has great potential for process safety, environmental friendliness, and coupling with intermittent renewable energy sources (such as wind and solar power).

[0003] Ethylene glycol (EG), a readily available bulk chemical (which can be produced via biomass or coal chemical routes), produces glycolic acid (GA), a highly valuable high-end fine chemical, through selective oxidation. Glycolic acid is widely used in cosmetics, biodegradable polymers (such as polyglycolic acid), pharmaceuticals, and cleaning agents. Currently, industrial production of glycolic acid mainly relies on the high-temperature, high-pressure nitric acid oxidation of ethylene glycol or the formaldehyde carbonylation process. These traditional processes suffer from inherent drawbacks such as severe equipment corrosion, generation of large amounts of toxic waste gases including nitrogen oxides and carbon monoxide, high energy consumption, and poor safety. Therefore, developing a green, safe, and efficient new process for ethylene glycol oxidation has significant industrial application value and economic and environmental implications.

[0004] Electrocatalytic oxidation technology provides an ideal route for the green conversion of ethylene glycol to glycolic acid. This reaction is typically carried out in an alkaline medium, and the core challenge lies in designing efficient and stable electrocatalysts to achieve high selectivity for the target product, glycolic acid. The ethylene glycol molecule contains two primary hydroxyl groups, and its electrooxidation process is complex, potentially involving multiple electron transfer steps and generating various intermediates and byproducts, such as glyoxal, oxalic acid, formate, and even complete oxidation to carbon dioxide. Therefore, the catalyst must be able to precisely activate the CH bond, promoting the selective oxidation of the first hydroxyl group to a carboxyl group while effectively inhibiting the over-oxidation of the second hydroxyl group or the breaking of the C / C bond.

[0005] Currently, research in this field mainly focuses on the following types of catalysts: Noble metal-based catalysts (such as Pt, Pd and their alloys): Although these catalysts have certain activity, their selectivity for glycolic acid is generally low, and the reaction tends to produce C1 products (such as formate and CO2). In addition, noble metals are expensive and scarce, and are easily poisoned and deactivated by intermediate products (such as CO) during the reaction, which seriously restricts their prospects for large-scale industrial application.

[0006] Non-precious metal catalysts (such as oxides / hydroxides of Ni, Co, and Cu): These materials are inexpensive and show potential to replace precious metals. Nickel-based catalysts, in particular, exhibit good activity for alcohol oxidation under alkaline conditions. However, most existing non-precious metal catalysts still show unsatisfactory selectivity for the electrooxidation of ethylene glycol to glycolic acid. Their surface active sites often lack the ability to precisely control the reaction pathway, resulting in a broad product distribution. The Faraday efficiency for glycolic acid is typically below 80%, making it difficult to meet the economic requirements of industrial production.

[0007] Current Status of Catalyst Structure Design: Current research generally recognizes that the electronic structure, crystal facet exposure, defect engineering, and microstructure of a catalyst have a decisive influence on its catalytic performance. For example, constructing nanostructures with abundant active interfaces, specific crystal facets, or oxygen vacancies helps to improve activity. However, for the specific reaction "ethylene glycol → glycolic acid," how to design a non-noble metal catalyst active center that can simultaneously optimize reactant adsorption, intermediate stabilization, and product desorption processes through precise and controllable preparation methods remains a key unsolved scientific problem and technological bottleneck in this field.

[0008] In summary, existing catalysts for the electrocatalytic oxidation of ethylene glycol to glycolic acid generally suffer from problems such as insufficient selectivity, dependence on precious metals, poor stability, or complex and uncontrollable preparation methods. Therefore, there is an urgent need to develop a novel, low-cost, highly active, and ultra-highly selective non-precious metal electrocatalyst, coupled with a simple and scalable preparation method, to promote the practical application of this green process for the electrocatalytic synthesis of glycolic acid from ethylene glycol. Summary of the Invention

[0009] To address the problems of low selectivity, reliance on noble metals, poor stability, and complex preparation processes in existing catalysts for the electrocatalytic oxidation of ethylene glycol to glycolic acid, this invention aims to provide a novel non-noble metal composite catalyst and its simple and controllable preparation method. This invention includes the following aspects: 1. Develop a non-noble metal catalyst and corresponding active center that can accurately and efficiently activate specific primary hydroxyl groups in ethylene glycol molecules, thereby highly selectively guiding the reaction pathway to the formation of glycolic acid and effectively suppressing side reactions (such as excessive oxidation or C / C bond cleavage).

[0010] 2. Construct a catalyst support structure that combines high conductivity, high stability, and abundant active sites to promote electron transport, stabilize active centers, and improve overall catalytic efficiency.

[0011] 3. To provide a catalyst preparation method that is simple, low-cost, easy to control, and highly reproducible, so as to meet the needs of future large-scale production.

[0012] To achieve the above-mentioned technical objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a non-precious metal composite catalyst, the catalyst having a multi-level composite structure comprising: Conductive carbon substrate: The substrate is a three-dimensional conductive network formed by interwoven one-dimensional carbon nanotubes, and metallic nickel nanoparticles (Ni NPs) are grown in situ at the tips of the carbon nanotubes; the structure is reconstructed from nickel-based metal-organic framework (Ni-MOF) precursors through a high-temperature thermal reduction and carbonization process, wherein the carbon nanotubes originate from the catalytic graphitization growth of organic ligands in the MOF, and the nickel nanoparticles serve as growth catalysts and remain at the tips of the tubes.

[0013] Molecular active center: Cobalt phthalocyanine molecules are loaded onto the conductive carbon substrate via non-covalent bonding (such as π-π stacking or physical adsorption). The cobalt phthalocyanine molecule serves as the primary catalytic active center, and the central cobalt atom and the substituent structures surrounding the phthalocyanine macrocycle are key to regulating catalytic selectivity.

[0014] Preferably, the cobalt phthalocyanine molecule is a derivative with different substituents, including but not limited to: unsubstituted cobalt phthalocyanine (CoPc), tetraaminocobalt phthalocyanine (CoTAPc), tetracarboxycobalt phthalocyanine (CoTCPc), or tetrasulfonic cobalt phthalocyanine (CoTSPc); different substituents can finely control the selectivity of the ethylene glycol oxidation pathway by changing the electron cloud density of the phthalocyanine macrocycle, the valence state of the central cobalt atom, and the binding energy with the reaction intermediate.

[0015] Preferably, the nickel nanoparticles have a size of 10-50 nanometers, which form a strong chemical bond with the tip of the carbon nanotube, enhancing the structural stability and conductivity of the substrate.

[0016] Secondly, the present invention provides a method for preparing the above-mentioned catalyst, comprising the following steps: S1: Preparation of Ni-MOF precursor: A certain amount of 1,4-phthalic acid was ultrasonically dispersed in a certain amount of N,N-dimethylformamide to obtain a first dispersion; at the same time, a certain amount of nickel nitrate was dissolved in a certain amount of water to obtain a first solution. Then, the first dispersion and the first solution are thoroughly mixed to obtain mixture I. The resulting mixture I is then transferred to an autoclave and heated at 150~200℃ for 10~15 hours to carry out the reaction. After the reaction is completed, the precipitate is collected and washed with water and anhydrous ethanol in sequence. Finally, it is vacuum dried to obtain Ni-MOF precursor powder. S2: High-temperature thermal reconstruction for the preparation of carbon nanotube substrates (Ni-NPs@CNT): The Ni-MOF precursor powder obtained in step S1 was subjected to high-temperature heat treatment under an inert atmosphere to obtain a carbon nanotube composite material loaded with nickel nanoparticles, denoted as Ni-NPs@CNT. S3: Loading of cobalt phthalocyanine molecules: The Ni-NPs@CNT material obtained in step S2 is uniformly dispersed in organic solvent I to form dispersion A; the cobalt phthalocyanine molecule with the selected structure is dissolved in organic solvent I to form solution B; Under ultrasonic and stirring conditions, solution B is slowly added dropwise to dispersion A, and the mixture is continuously stirred and ultrasonically treated for a certain period of time (e.g., 6-24 hours, preferably 6-12 hours) to allow cobalt phthalocyanine molecules to be fully adsorbed onto the carbon surface of Ni-NPs@CNT. Subsequently, the mixture is centrifuged, washed, and vacuum dried to obtain a non-noble metal composite catalyst, denoted as CoPc / Ni-NPs@CNT (where CoPc can be replaced by the name of a specific derivative, such as CoTAPc / Ni-NPs@CNT, etc.).

[0017] Specifically, in step S1, the ratio of 1,4-phthalic acid to N,N-dimethylformamide is 1 mol: (1~5) L.

[0018] Specifically, in step S1, the ratio of nickel nitrate to water is 1 mol: (2~4) L.

[0019] Specifically, in step S2, the inert atmosphere is formed by one or more of nitrogen, argon, and helium.

[0020] Specifically, in step S2, the heat treatment procedure is as follows: the temperature is increased to 300-900°C at a rate of 2-8°C / min, and held at this temperature for 1-3 hours; during this process, the organic ligands in the MOF partially decompose and catalyze the growth to form carbon nanotubes (CNTs), while nickel ions are reduced to metallic nickel nanoparticles (Ni NPs) and embedded in the tips of the carbon nanotubes.

[0021] Specifically, in step S3, organic solvent I is N,N-dimethylformamide (DMF), DMSO, or ethanol.

[0022] Specifically, in step S3, when preparing solution A, the ratio of Ni-NPs@CNT material to organic solvent I is 1g:(10~20)L.

[0023] Specifically, in step S3, when preparing solution B, the ratio of cobalt phthalocyanine molecules to organic solvent I is 1g:(10~20)L.

[0024] Specifically, in step S3, the cobalt phthalocyanine molecule is one or more of unsubstituted cobalt phthalocyanine (CoPc), tetraaminocobalt phthalocyanine (CoTAPc), tetracarboxycobalt phthalocyanine (CoTCPc), and tetrasulfonic cobalt phthalocyanine (CoTSPc).

[0025] As another preferred technical solution, the method for preparing the catalyst of this application includes the following steps: (1) Preparation of Ni-MOF precursor: A certain amount of 1,4-phthalic acid was ultrasonically dispersed in a certain amount of N,N-dimethylformamide to obtain a first dispersion; at the same time, a certain amount of nickel nitrate was dissolved in a certain amount of water to obtain a first solution. Then, the first dispersion and the first solution are thoroughly mixed to obtain mixture I. The resulting mixture I is then transferred to an autoclave and heated at 150~200℃ for 10~15 hours to carry out the reaction. After the reaction is completed, the precipitate is collected and washed with water and anhydrous ethanol in sequence. Finally, it is vacuum dried to obtain Ni-MOF precursor powder. (2) High-temperature thermal reconstruction for the preparation of carbon nanotube substrates (Ni-NPs@CNT): The Ni-MOF precursor powder obtained in step (1) was subjected to high-temperature heat treatment under an inert atmosphere to obtain a carbon nanotube composite material loaded with nickel nanoparticles, denoted as Ni-NPs@CNT; (3) Loading of cobalt phthalocyanine molecules: The selected cobalt phthalocyanine molecules were dissolved in organic solvent I to obtain a second solution. The Ni-NPs@CNT material prepared in step (2) was then dispersed in the second solution to obtain a mixture II. The mixture II was ultrasonically treated for a certain time and then stirred for 6 to 24 hours to allow the cobalt phthalocyanine molecules to be fully adsorbed on the carbon surface of Ni-NPs@CNT. Subsequently, the mixture was centrifuged, washed, and vacuum dried to obtain a non-noble metal composite catalyst, denoted as CoPc / Ni-NPs@CNT (where CoPc can be replaced by a specific derivative name, such as CoTAPc / Ni-NPs@CNT, etc.).

[0026] Preferably, in step (1), the ratio of 1,4-phthalic acid to N,N-dimethylformamide is 1 mol: (1~5) L.

[0027] Preferably, in step (1), the ratio of nickel nitrate to water is 1 mol: (2~4) L.

[0028] Preferably, in step (2), the inert atmosphere is formed by a mixture of one or more of nitrogen, argon, and helium.

[0029] Preferably, in step (2), the heat treatment procedure is as follows: the temperature is increased to 300-900°C at a rate of 2-8°C / min, and held at this temperature for 1-3 hours. During this process, the organic ligands in the MOF partially decompose and catalyze the growth to form carbon nanotubes (CNTs), while nickel ions are reduced to metallic nickel nanoparticles (Ni NPs) and embedded in the tips of the carbon nanotubes.

[0030] Preferably, in step (3), the organic solvent I is N,N-dimethylformamide DMF, DMSO or ethanol.

[0031] Preferably, in step (3), when preparing the second solution, the ratio of cobalt phthalocyanine molecules to organic solvent I is 1g:(10~20)L.

[0032] Preferably, in step (3), when preparing mixture II, the mass ratio of cobalt phthalocyanine molecules to Ni-NPs@CNT material is 1:(10~20).

[0033] Preferably, in step (3), the cobalt phthalocyanine molecule is one or more of unsubstituted cobalt phthalocyanine (CoPc), tetraaminocobalt phthalocyanine (CoTAPc), tetracarboxycobalt phthalocyanine (CoTCPc), and tetrasulfonic cobalt phthalocyanine (CoTSPc).

[0034] Furthermore, the present invention also provides the application of the aforementioned non-precious metal composite catalyst in the preparation of glycolic acid by ethylene glycol oxidation.

[0035] The catalyst of this invention has a multi-level composite structure: a nickel-based metal-organic framework is used as a precursor, which is subjected to high-temperature thermal reduction and carbonization reconstruction to form a conductive carbon nanotube substrate with nickel nanoparticles loaded at its tip; on this basis, cobalt phthalocyanine molecules with well-defined active centers are loaded through non-covalent bonding. By controlling the substituent structure around the cobalt phthalocyanine molecules, the selectivity of the catalyst for the ethylene glycol oxidation pathway can be finely tuned, achieving efficient and directional conversion of glycolic acid products. The catalyst of this invention is made entirely of non-precious metals and has the advantages of high activity, excellent selectivity, good stability, and low cost; its preparation process is simple and controllable, with good reproducibility, providing an efficient and reliable catalyst solution for the green electrocatalytic value-added conversion of ethylene glycol.

[0036] Compared with the prior art, the catalyst and its preparation method provided by the present invention have the following significant advantages: 1. Extremely high catalytic selectivity: This invention creatively combines a molecular catalyst (cobalt phthalocyanine) with a nanostructure support (Ni NPs@CNT). The cobalt phthalocyanine molecule has a well-defined and uniform active center (Co-N4), and its surrounding substituents (such as amino and carboxyl groups) can act as proton or electronic regulation groups, precisely optimizing the adsorption / desorption behavior of ethylene glycol and its oxidation intermediates. This locks the reaction pathway onto the step of glycolic acid formation, achieving a glycolic acid Faradaic efficiency close to 95% or even higher.

[0037] 2. Excellent Activity and Stability: The unique Ni NPs@CNT support not only provides a high specific surface area and abundant adsorption sites, but its excellent three-dimensional conductive network also ensures rapid electron transport. The presence of the advanced nickel nanoparticles can also generate a potential electronic synergistic effect with cobalt phthalocyanine, further enhancing intrinsic activity. Simultaneously, the carbon nanotube framework and stable chemical connections endow the catalyst with excellent physical and electrochemical stability, exhibiting minimal activity and selectivity degradation during long-term electrolysis tests.

[0038] 3. Low cost and environmentally friendly: The catalyst is composed entirely of non-precious metals (Ni, Co) and carbon materials, making the raw material cost far lower than that of precious metal catalysts such as platinum and palladium. The preparation process does not require the use of highly corrosive reagents, the pyrolysis step is completed in one step, the molecular loading process is mild, and the overall process is green and economical.

[0039] 4. The preparation method offers strong controllability and good reproducibility: By adjusting the morphology, pyrolysis temperature, and time of the Ni-MOF precursor, the diameter and length of the resulting carbon nanotubes and the size of the nickel nanoparticles can be precisely controlled. By selecting cobalt phthalocyanine molecules with different substituents, the catalytic performance can be flexibly adjusted like a "molecular switch," achieving "on-demand design" of product selectivity. This method is simple in procedure, with easily controllable parameters, and possesses good process scalability and product consistency.

[0040] In summary, this invention provides a novel, high-performance, cost-effective, and easy-to-prepare highly selective electrocatalyst, offering a promising technical solution for the industrial application of green electrosynthesis of glycolic acid from ethylene glycol. Attached Figure Description

[0041] Figure 1 The X-ray diffraction pattern of the product obtained in Example 1 of this application (Wide-angle XRD patterns of CoTAPc / Ni NPs@CNT). Figure 2 This is a field emission scanning electron microscope image of the product obtained in Example 1 of this application (SEM image of CoTAPc / Ni NPs@CNT). Figure 3Linear scanning voltammetric curves (CV curves of CoTAPc / Ni NPs@CNT in 1 M KOH / 0.5 M EG) of the product obtained in Example 1 of this application at different scan rates. Figure 4 The polarization curves of the product obtained in Example 1 of this application in glycerol electrolyte systems with and without glycerol (LSV curves in 1 M KOH with and without 0.5 M EG). Detailed Implementation

[0042] The technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application. The raw materials or reagents used in the following embodiments are all commercially available or self-made.

[0043] In the following examples, room temperature or normal temperature refers to 25±5℃.

[0044] Example 1 Example 1 provides a method for preparing a catalyst for the selective oxidation of ethylene glycol to prepare glycolic acid. The specific steps are as follows: (1) Preparation of Ni-MOF precursor: 5 mmol of 1,4-phthalic acid was ultrasonically dispersed in 15 mL of N,N-dimethylformamide to obtain a first dispersion; simultaneously, 6.5 mmol of nickel nitrate was dissolved in 15 mL of deionized water to obtain a first solution.

[0045] Then, the first dispersion and the first solution were thoroughly mixed to obtain mixture I. The obtained mixture I was transferred to a 50 mL high-pressure reactor lined with polytetrafluoroethylene and heated at 180 °C for 12 hours. After the reaction was completed, the precipitate was collected and washed with deionized water and anhydrous ethanol in sequence. Finally, it was dried under vacuum to obtain Ni-MOF precursor powder. (2) High-temperature thermal reconstruction for the preparation of carbon nanotube substrates (Ni-NPs@CNT): The Ni-MOF prepared in step (1) was heated to different temperatures (temperature range of 300-900℃, specifically 300℃, 500℃, 700℃, and 900℃) in a nitrogen atmosphere at a heating rate of 7°C / min, with a nitrogen flow rate of 100 mL / min, and held at this temperature for 2 hours, and then naturally cooled to room temperature; respectively, carbon nanotube composite materials loaded with nickel nanoparticles were obtained: Ni-NPs@CNT300, Ni-NPs@CNT500, Ni-NPs@CNT700 and Ni-NPs@CNT900.

[0046] (3) Loading of cobalt phthalocyanine molecules: A CoPc / DMF solution was obtained by dissolving 2 mg of CoPc (unsubstituted cobalt phthalocyanine) in 30 mL of DMF. Then, 30 mg of NiNP-C (i.e. Ni-NPs@CNT300, Ni-NPs@CNT500, Ni-NPs@CNT700 or Ni-NPs@CNT900 in step (2)) was dispersed in CoPc / DMF solution to obtain mixture II. Mixture II was ultrasonically treated for 30 minutes and then stirred for 24 hours to promote the solution to penetrate into carbon nanotubes. Subsequently, the product was centrifuged and thoroughly washed with DMF, ethanol and deionized water in sequence. Finally, CoTAPc / Ni-NPs@CNT powder was obtained after freeze drying.

[0047] Figure 1 The X-ray diffraction pattern of the product obtained in Example 1 of this application (Wide-angle XRD patterns of CoTAPc / Ni NPs@CNT). Figure 2 This is a field emission scanning electron microscope image of the product obtained in Example 1 of this application (SEM image of CoTAPc / Ni NPs@CNT). Figure 3 Linear scanning voltammetric curves (CV curves of CoTAPc / Ni NPs@CNT in 1 M KOH / 0.5 M EG) of the product obtained in Example 1 of this application at different scan rates. Figure 4 The polarization curves of the product obtained in Example 1 of this application in glycerol electrolyte systems with and without glycerol (LSV curves in 1 M KOH with and without 0.5 M EG).

[0048] Example 2 Example 2 provides a method for preparing a catalyst for the selective oxidation of ethylene glycol to prepare glycolic acid. The difference between Example 2 and Example 1 is that step (3) is different. 30 mg of Ni-NPs@CNT material obtained in step S2 was uniformly dispersed in DMF to form dispersion A; 2 mg of CoPc (unsubstituted cobalt phthalocyanine) was dissolved in DMF to form solution B. Under ultrasonic and stirring conditions, solution B was slowly added dropwise to dispersion A, and the mixture was continuously stirred and ultrasonically treated for 24 hours to allow cobalt phthalocyanine molecules to be fully adsorbed onto the carbon surface of Ni-NPs@CNT. The mixture was then centrifuged and thoroughly washed with DMF, ethanol and deionized water, and finally vacuum dried to obtain the non-noble metal composite catalyst CoTAPc / Ni-NPs@CNT powder.

[0049] The foregoing has shown and described the basic principles and main features of the present invention, as well as its advantages. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A catalyst for the selective oxidation of ethylene glycol to prepare glycolic acid, characterized in that, The catalyst has a multi-level composite structure, comprising: Conductive carbon substrate: The substrate is a three-dimensional conductive network formed by interwoven one-dimensional carbon nanotubes, and metallic nickel nanoparticles are grown in situ at the tips of the carbon nanotubes. Molecular active center: Cobalt phthalocyanine molecules are loaded on the conductive carbon substrate via non-covalent bonding; the cobalt phthalocyanine molecules serve as the main catalytic active center.

2. The catalyst according to claim 1, characterized in that, The cobalt phthalocyanine molecule is a derivative with different substituents, including but not limited to: unsubstituted cobalt phthalocyanine, tetraaminocobalt phthalocyanine, tetracarboxycobalt phthalocyanine, or tetrasulfonic cobalt phthalocyanine.

3. The catalyst according to claim 1, characterized in that, The nickel nanoparticles, with a size of 10-50 nanometers, form a strong chemical bond with the tips of carbon nanotubes, enhancing the structural stability and conductivity of the substrate.

4. A method for preparing a catalyst for the selective oxidation of ethylene glycol to prepare glycolic acid, characterized in that, Includes the following steps: S1: Preparation of Ni-MOF precursor: A certain amount of 1,4-phthalic acid was ultrasonically dispersed in a certain amount of N,N-dimethylformamide to obtain a first dispersion; at the same time, a certain amount of nickel nitrate was dissolved in a certain amount of water to obtain a first solution. Then, the first dispersion and the first solution are mixed to obtain mixture I. The obtained mixture I is then transferred to a reaction vessel and heated at 150~200℃ for 10~15 hours to carry out the reaction. After the reaction is completed, the precipitate is collected and washed with water and anhydrous ethanol in sequence. Finally, it is vacuum dried to obtain Ni-MOF precursor powder. S2: High-temperature thermal reconstruction for preparing carbon nanotube substrates: The Ni-MOF precursor powder obtained in step S1 was subjected to high-temperature heat treatment under an inert atmosphere to obtain a carbon nanotube composite material loaded with nickel nanoparticles, denoted as Ni-NPs@CNT. S3: Loading of cobalt phthalocyanine molecules: The Ni-NPs@CNT material obtained in step S2 is uniformly dispersed in organic solvent I to form dispersion A; cobalt phthalocyanine molecules are dissolved in organic solvent I to form solution B; Under ultrasonic and stirring conditions, solution B was added to dispersion A, and the mixture was continuously stirred and ultrasonically treated for 6-24 hours to allow cobalt phthalocyanine molecules to be fully adsorbed on the carbon surface of Ni-NPs@CNT. Subsequently, the mixture was centrifuged, washed, and vacuum dried to obtain a non-noble metal composite catalyst, denoted as CoPc / Ni-NPs@CNT.

5. The preparation method according to claim 4, characterized in that, In step S1, the ratio of 1,4-phthalic acid to N,N-dimethylformamide is 1 mol: (1~5) L; In step S1, the ratio of nickel nitrate to water is 1 mol: (2~4) L.

6. The preparation method according to claim 4, characterized in that, In step S3, organic solvent I is DMF, DMSO, or ethanol; In step S3, when preparing solution A, the ratio of Ni-NPs@CNT material to organic solvent I is 1g:(10~20)L; In step S3, when preparing solution B, the ratio of cobalt phthalocyanine molecules to organic solvent I is 1g:(10~20)L; In step S3, the cobalt phthalocyanine molecule is one or more of unsubstituted cobalt phthalocyanine, tetraaminocobalt phthalocyanine, tetracarboxycobalt phthalocyanine, and tetrasulfonic cobalt phthalocyanine.

7. A method for preparing a catalyst for the selective oxidation of ethylene glycol to prepare glycolic acid, characterized in that, Includes the following steps: (1) Preparation of Ni-MOF precursor: A certain amount of 1,4-phthalic acid was ultrasonically dispersed in a certain amount of N,N-dimethylformamide to obtain a first dispersion; at the same time, a certain amount of nickel nitrate was dissolved in a certain amount of water to obtain a first solution. Then, the first dispersion and the first solution are thoroughly mixed to obtain mixture I. The resulting mixture I is then transferred to a reaction vessel and heated at 150~200℃ for 10~15 hours to carry out the reaction. After the reaction is completed, the precipitate is collected and washed with water and anhydrous ethanol in sequence. Finally, it is vacuum dried to obtain Ni-MOF precursor powder. (2) High-temperature thermal reconstruction for the preparation of carbon nanotube substrates: The Ni-MOF precursor powder obtained in step (1) was subjected to high-temperature heat treatment under an inert atmosphere to obtain a carbon nanotube composite material loaded with nickel nanoparticles, denoted as Ni-NPs@CNT; (3) Loading of cobalt phthalocyanine molecules: Cobalt phthalocyanine molecules were dissolved in organic solvent I to obtain a second solution. Then, the Ni-NPs@CNT material prepared in step (2) was dispersed in the second solution to obtain a mixture II. The mixture II was ultrasonically treated for a certain time and then stirred for 6 to 24 hours to allow the cobalt phthalocyanine molecules to be fully adsorbed on the carbon surface of Ni-NPs@CNT. Subsequently, the mixture was centrifuged, washed, and vacuum dried to obtain a non-noble metal composite catalyst, denoted as CoPc / Ni-NPs@CNT.

8. The preparation method according to claim 7, characterized in that, In step (1), the ratio of 1,4-phthalic acid to N,N-dimethylformamide is 1 mol: (1~5) L; In step (1), the ratio of nickel nitrate to water is 1 mol: (2~4) L.

9. The preparation method according to claim 7, characterized in that, In step (3), organic solvent I is DMF, DMSO, or ethanol; In step (3), when preparing the second solution, the ratio of cobalt phthalocyanine molecules to organic solvent I is 1 g: (10~20) L; In step (3), when preparing mixture II, the mass ratio of cobalt phthalocyanine molecules to Ni-NPs@CNT materials is 1:(10~20). In step (3), the cobalt phthalocyanine molecule is one or more of unsubstituted cobalt phthalocyanine, tetraaminocobalt phthalocyanine, tetracarboxycobalt phthalocyanine, and tetrasulfonic cobalt phthalocyanine.

10. The use of the catalyst according to any one of claims 1 to 3 in the preparation of glycolic acid by oxidation of ethylene glycol.

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