CuO active site modified nitrogen-doped porous carbon catalyst as well as preparation method and application thereof

Abstract

The invention discloses a preparation method of a CuO active site modified nitrogen-doped porous carbon catalyst, which specifically comprises the following steps: taking copper salt and benzenetricarboxylic acid as raw materials, then adding a nitrogen source precursor, and preparing N / Cu-MOF by adopting a hydrothermal method; and etching and oxidizing by using a potassium hydroxide solution to finally prepare the CuO active site modified nitrogen-doped porous carbon catalyst. The prepared CuO / N-C catalyst can be used for electro-catalysis acetylene semi-hydrogenation reaction, high Faraday efficiency and selectivity can still be kept under large flow, the heteroatom N serves as a strong electron-donating ligand, adsorption of reactant acetylene and desorption of product ethylene in the acetylene semi-hydrogenation reaction process can be effectively promoted, and the selectivity of acetylene is improved. The selectivity and Faraday efficiency of ethylene can be obviously improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of catalyst preparation, and in particular relates to a preparation method of a CuO active site modified nitrogen-doped porous carbon catalyst, and also relates to a CuO active site modified nitrogen-doped porous carbon catalyst and application thereof. Background Art

[0002] Selective hydrogenation of acetylene to produce ethylene has become a new method for high value-added coal-based chemicals. Commercial industrial catalysts are mainly precious metal palladium catalysts, and the catalytic temperature is 50-80°C for the optimal activity range. When the catalyst exceeds 85°C, its selectivity will drop sharply. At the same time, a large amount of hydrogen needs to be introduced during the catalytic hydrogenation of acetylene. The conversion rate of the reactant acetylene is greater than 90%, and the selectivity of the reaction product ethylene is about 85%. Therefore, it is necessary to develop an acetylene hydrogenation process (C2H2+2H2O+2e - →C2H4+2OH - ) is of great significance for achieving clean and efficient utilization of coal resources. However, low Faradaic efficiency, ethylene selectivity, and catalyst stability during electrocatalytic acetylene semi-hydrogenation at high current densities, as well as the strongly competing hydrogen evolution reaction, have been key challenges hindering the practical application of this process. Therefore, designing high-performance electrocatalytic acetylene semi-hydrogenation catalysts has become a research priority.

[0003] Existing methods for preparing acetylene semi-hydrogenation catalysts include: (1) impregnation method: impregnate the active metal (such as Pd, Ag, Cu, etc.) precursor solution into a carrier (such as Al2O3, SiO2, carbon material, etc.), and obtain the catalyst after drying, calcination, and reduction. This method has the advantages of simple process and easy large-scale production. However, this method will cause the metal particles to agglomerate, and the catalyst activity and selectivity are both low; (2) colloidal method: by chemically reducing metal salts to form nano-colloidal particles, and then loading them onto the carrier, the size of the metal nanoparticles can be precisely controlled (such as 15nm), and the selectivity and activity can be improved. However, this method is complex to prepare and has high cost (stabilizers and reducing agents are required), and residual organic matter may block the active sites; (3) alloying method: the main metal (Pd) and the second metal (Ag, Cu, Au, etc.) are made into an alloy (such as PdAg), and the electronic structure is adjusted through synergistic effect. The alloy effect inhibits excessive hydrogenation, improves the anti-carbon deposition ability and stability; However, this method has complex preparation process and is time-consuming. Summary of the Invention

[0004] The first purpose of the present invention is to provide a method for preparing a CuO active site modified nitrogen-doped porous carbon catalyst, which solves the problems of low selectivity and poor stability of existing catalysts in the acetylene semi-hydrogenation reaction.

[0005] The second object of the present invention is to provide a CuO active site modified nitrogen-doped porous carbon catalyst.

[0006] The third object of the present invention is to provide an application of a CuO active site modified nitrogen-doped porous carbon catalyst in the electrocatalytic acetylene semi-hydrogenation reaction.

[0007] The first technical solution adopted in the present invention is a preparation method of a CuO active site modified nitrogen-doped porous carbon catalyst, which uses copper salt and benzenetricarboxylic acid as raw materials, then adds a nitrogen source precursor, and adopts a hydrothermal method to prepare N / Cu-MOF; then it is etched and oxidized with potassium hydroxide solution to finally prepare a CuO active site modified nitrogen-doped porous carbon catalyst.

[0008] The present invention is also characterized in that:

[0009] Please follow the steps below to implement it:

[0010] Step 1, synthesis of nitrogen-doped copper-based metal organic framework compounds; specifically:

[0011] Step 1.1, dissolving a copper salt in N,N-dimethylformamide to obtain a copper salt solution; dissolving benzenetricarboxylic acid in N,N-dimethylformamide to obtain a benzenetricarboxylic acid solution; mixing the copper salt solution with a nitrogen source precursor, stirring uniformly, adding the benzenetricarboxylic acid solution, and stirring uniformly to obtain a precursor mixture;

[0012] Step 1.2, placing the precursor mixture obtained in step 1.1 in a high-pressure reactor for hydrothermal reaction, centrifuging after the reaction, washing with N,N-dimethylformamide and anhydrous ethanol several times in sequence, and vacuum drying to obtain a nitrogen-doped copper-based metal organic framework compound;

[0013] Step 2: dissolving the nitrogen-doped copper-based metal organic framework compound in water, ultrasonically stirring, then adding potassium hydroxide solution and stirring to react. After the reaction is completed, centrifuging, washing with water and ethanol several times in sequence, and freeze-drying to obtain a CuO active site modified nitrogen-doped porous carbon catalyst.

[0014] In step 1.1, the mass ratio of copper salt, benzenetricarboxylic acid and nitrogen source precursor is 0.3-1.5:0.1-0.8:0.1-0.5; the copper salt is any one of copper nitrate, copper sulfate, copper carbonate and copper chloride; and the nitrogen source precursor is any one of polyvinylpyrrolidone, melamine and pyrazole.

[0015] In step 1.2, the hydrothermal reaction time is 10 to 36 hours, the hydrothermal reaction temperature is 50 to 120° C.; the centrifugal speed is 5000 to 10000 rpm, and the centrifugal time is 3 to 20 minutes; the vacuum drying temperature is 30 to 80° C., and the drying time is 8 to 36 hours.

[0016] In step 2, the mass ratio of the nitrogen-doped copper-based metal organic framework compound to water is 0.1-1:5-10; and the concentration of the potassium hydroxide solution is 0.5-3 mol / L.

[0017] In step 2, the stirring reaction time is 5 to 12 hours, the stirring rate is 1000 to 5000 rpm; the centrifugal rate is 5000 to 10000 rpm, and the centrifugal time is 3 to 20 minutes; the freeze-drying temperature is -30 to -80°C, and the freeze-drying time is 12 to 36 hours.

[0018] The second technical solution adopted by the present invention is a nitrogen-doped porous carbon catalyst prepared by a preparation method of a CuO active site modified nitrogen-doped porous carbon catalyst.

[0019] The third technical solution adopted by the present invention is the application of CuO active site modified nitrogen-doped porous carbon catalyst in the electrocatalytic acetylene semi-hydrogenation reaction.

[0020] The beneficial effects of the present invention are:

[0021] (1) The present invention forms a CuO active site modified nitrogen-doped porous carbon catalyst (CuO / NC) by deriving a nitrogen-doped copper-based metal organic framework compound. Compared with traditional noble metal Pd-based catalysts, Cu-based catalysts have lower costs. In addition, compared with traditional carbon materials, metal organic framework-derived nitrogen-doped carbon can obtain an ordered structure, controllable pore size and specific surface area, thereby obtaining highly active CuO and nitrogen coordinated catalytic active sites.

[0022] (2) The heteroatom N in the catalyst of the present invention acts as a strong electron-donating ligand, which can effectively promote the adsorption of the reactant acetylene and the desorption of the product ethylene during the acetylene semi-hydrogenation reaction, enabling the CuO / NC catalyst to achieve high Faradaic efficiency, stability, and selectivity under high current density conditions;

[0023] (3) The CuO / NC catalyst prepared by the present invention can efficiently convert acetylene into ethylene through an electrocatalytic process under normal temperature and pressure conditions using water as a hydrogen source, which is of great significance for the low-carbon and green development of acetylene chemical industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is the SEM image of the CuO / NC catalyst prepared in Example 1;

[0025] Figure 2 XRD pattern of the CuO / NC catalyst prepared in Example 1;

[0026] Figure 3 This is the XPS spectrum of the CuO / NC catalyst prepared in Example 1;

[0027] Figure 4 The linear sweep voltammogram of the CuO / NC catalyst prepared in Example 1 under acetylene gas and argon atmosphere;

[0028] Figure 5 This is a graph showing the Faradaic efficiency and selectivity of the CuO / NC catalyst prepared in Example 1 in acetylene gas. DETAILED DESCRIPTION

[0029] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0030] The preparation method of the CuO active site modified nitrogen-doped porous carbon catalyst of the present invention comprises the following steps: using copper salt and benzenetricarboxylic acid as raw materials, adding a nitrogen source precursor, and preparing N / Cu-MOF by a hydrothermal method; then etching and oxidizing with a potassium hydroxide solution to finally prepare a CuO active site modified nitrogen-doped porous carbon (CuO / NC) catalyst;

[0031] Please follow the steps below to implement it:

[0032] Step 1, synthesis of nitrogen-doped copper-based metal organic framework compounds; specifically:

[0033] Step 1.1, dissolving a copper salt in N,N-dimethylformamide to obtain a copper salt solution; dissolving benzenetricarboxylic acid in N,N-dimethylformamide to obtain a benzenetricarboxylic acid solution; mixing the copper salt solution with a nitrogen source precursor, stirring uniformly, adding the benzenetricarboxylic acid solution, and stirring uniformly to obtain a precursor mixture;

[0034] The mass ratio of copper salt, benzenetricarboxylic acid and nitrogen source precursor is 0.3-1.5:0.1-0.8:0.1-0.5;

[0035] The copper salt is any one of copper nitrate, copper sulfate, copper carbonate and copper chloride;

[0036] The nitrogen source precursor is any one of polyvinyl pyrrolidone, melamine, and pyrazole;

[0037] Step 1.2, placing the precursor mixture obtained in step 1.1 in a polytetrafluoroethylene-lined autoclave for hydrothermal reaction. After the reaction is completed, centrifugation is performed, and the mixture is washed with N,N-dimethylformamide and anhydrous ethanol several times in sequence, and vacuum dried to obtain a nitrogen-doped copper-based metal organic framework compound (N / Cu-MOF);

[0038] The hydrothermal reaction time is 10 to 36 hours, the hydrothermal reaction temperature is 50 to 120° C.; the centrifugal speed is 5000 to 10000 rpm, and the centrifugal time is 3 to 20 minutes; the vacuum drying temperature is 30 to 80° C., and the drying time is 8 to 36 hours;

[0039] Step 2: dissolving N / Cu-MOF in water, ultrasonically stirring, then adding potassium hydroxide solution and stirring to react. After the reaction is completed, centrifuging, washing with water and ethanol several times, and freeze-drying to obtain a CuO active site modified nitrogen-doped porous carbon (CuO / NC) catalyst;

[0040] The mass ratio of N / Cu-MOF to water is 0.1-1:5-10; the concentration of potassium hydroxide solution is 0.5-3 mol / L;

[0041] The stirring reaction time is 5 to 12 hours, the stirring rate is 1000 to 5000 rpm; the centrifugal rate is 5000 to 10000 rpm, and the centrifugal time is 3 to 20 minutes; the freeze-drying temperature is -30 to -80°C, and the freeze-drying time is 12 to 36 hours;

[0042] The CuO / NC catalyst prepared in the present invention can be used in the electrocatalytic acetylene semi-hydrogenation reaction, and can still maintain a high Faradaic efficiency and selectivity under high flow. In addition, the heteroatom N acts as a strong electron-donating ligand, which can effectively promote the adsorption of the reactant acetylene and the desorption of the product ethylene during the acetylene semi-hydrogenation reaction, and can significantly improve the selectivity and Faradaic efficiency of ethylene.

[0043] The catalyst of the present invention is used for electrocatalytic acetylene semi-hydrogenation, and the application conditions are: acetylene gas concentration is 0-99.99 vol.%, acetylene gas flow rate is 5-50 mL / min;

[0044] Example 1

[0045] The preparation method of the CuO active site modified nitrogen-doped porous carbon catalyst of the present invention is specifically as follows:

[0046] 0.8g of copper nitrate solid and 0.4g of benzenetricarboxylic acid solid were weighed and dissolved in 20mL of N,N-dimethylformamide and stirred to prepare copper salt solution and benzenetricarboxylic acid solution, respectively. 0.3g of polyvinyl pyrrolidone was added to the copper salt solution and stirred for 5 minutes. The benzenetricarboxylic acid solution was added and stirred to obtain a uniform solution. The resulting solution was placed in an autoclave and reacted at 50°C for 12 hours. After the reaction, the solution was centrifuged and washed until neutral. The solution was then dried in a vacuum oven at 60°C for 24 hours to obtain the N / Cu-MOF catalyst. 0.5g of N / Cu-MOF solid was then fully dissolved in 5mL of water, followed by the addition of 30mL of potassium hydroxide (1 mol / L) solution and stirring. After the reaction, the solution was washed with water and anhydrous ethanol, respectively, and the solid precipitate was collected by centrifugation and freeze-dried to obtain a CuO active site-modified nitrogen-doped porous carbon material, designated as CuO / NC.

[0047] Weigh 10 mg of the CuO / NC catalyst prepared above, add 2 mL of anhydrous ethanol and 50 μL of Nafion, and ultrasonically disperse at room temperature for 2 hours to form a homogeneous solution. Then, spray 20 μL of this solution evenly onto a 2 x 0.5 cm piece of carbon paper to form a working electrode. A Hg-HgO electrode was used as the reference electrode, nickel foam as the counter electrode, and 1 mol / L potassium hydroxide solution as the electrolyte at a flow rate of 20 rpm. Acetylene gas was introduced evenly at a rate of 20 mL / min.

[0048] The prepared catalyst was used to electrocatalyze the semi-hydrogenation of acetylene in an alkaline medium. The reaction conditions were: at room temperature and pressure, a three-electrode system with hydrophobic carbon paper coated with CuO / NC as the working electrode, a Hg-HgO electrode as the reference electrode, nickel foam as the counter electrode, and a 1 mol / L potassium hydroxide solution as the electrolyte. The electrochemical instrument used was a CS310M electrochemical workstation, and a HP-901 gas chromatograph for electrocatalytic acetylene hydrogenation testing. Cyclic voltammetry, linear sweep voltammetry, and galvanostatic polarization were used to test the catalyst's hydrogenation performance in alkaline medium.

[0049] Example 2

[0050] The preparation method of the CuO active site modified nitrogen-doped porous carbon catalyst of the present invention is specifically implemented according to the following steps:

[0051] 0.8 g of copper sulfate solid and 0.4 g of benzenetricarboxylic acid solid were weighed and dissolved in 25 mL of N,N-dimethylformamide and stirred to prepare copper salt solution and benzenetricarboxylic acid solution, respectively. 0.3 g of melamine was added to the copper salt solution and stirred for 10 minutes. The benzenetricarboxylic acid solution was then added and stirred to obtain a uniform solution. The resulting solution was placed in an autoclave and reacted at 60°C for 12 hours. After the reaction, the solution was centrifuged and washed until neutral. The solution was then dried in a vacuum oven at 60°C for 20 hours. 0.8 g of N / Cu-MOF solid was then fully dissolved in 8 mL of water, followed by the addition of 40 mL of potassium hydroxide (1 mol / L) solution and stirring. After the reaction, the solution was washed with water and anhydrous ethanol, respectively, and the solid precipitate was collected by centrifugation. Finally, the CuO active site-modified nitrogen-doped porous carbon material was freeze-dried to obtain CuO / NC.

[0052] Weigh 10 mg of the CuO / NC catalyst prepared above, add 2 mL of anhydrous ethanol and 50 μL of Nafion, and ultrasonically disperse at room temperature for 2 hours to form a homogeneous solution. Then, spray 20 μL of this solution evenly onto a 2 x 0.5 cm piece of carbon paper to form a working electrode. A Hg-HgO electrode was used as the reference electrode, nickel foam as the counter electrode, and 1 mol / L potassium hydroxide solution as the electrolyte at a flow rate of 20 rpm. Acetylene gas was introduced evenly at a rate of 20 mL / min.

[0053] The prepared catalyst was used to electrocatalyze the semi-hydrogenation of acetylene in an alkaline medium. The reaction conditions were: at room temperature and pressure, a three-electrode system with hydrophobic carbon paper coated with CuO / NC as the working electrode, a Hg-HgO electrode as the reference electrode, nickel foam as the counter electrode, and a 1 mol / L potassium hydroxide solution as the electrolyte. The electrochemical instrument used was a CS310M electrochemical workstation and a HP-901 gas chromatograph. Cyclic voltammetry, linear sweep voltammetry, and galvanostatic polarization were used to test the catalyst's hydrogenation performance in alkaline medium.

[0054] Example 3

[0055] The preparation method of the CuO active site modified nitrogen-doped porous carbon catalyst of the present invention is specifically as follows:

[0056] 0.8g of copper carbonate solid and 0.4g of benzenetricarboxylic acid solid were weighed and dissolved in 30ml of N,N-dimethylformamide, stirring thoroughly to prepare copper salt solution and benzenetricarboxylic acid solution. 0.3g of pyrazole was added to the copper salt solution and stirred for 15 minutes. The benzenetricarboxylic acid solution was then added and stirred thoroughly. The resulting solution was placed in an autoclave and reacted at 60°C for 24 hours. After the reaction, the solution was centrifuged and washed until neutral. The solution was then dried in a vacuum oven at 60°C for 24 hours. 1g of N / Cu-MOF solid was then fully dissolved in 10ml of water, 50ml of potassium hydroxide (1 mol / L) solution was added, and stirring thoroughly. After the reaction, the solution was washed with water and anhydrous ethanol, respectively, and the solid precipitate was collected by centrifugation. Finally, the CuO active site-modified nitrogen-doped porous carbon material was freeze-dried to obtain CuO / NC.

[0057] Weigh 10 mg of the CuO / NC catalyst prepared above, add 2 mL of anhydrous ethanol and 50 μL of Nafion, and ultrasonically disperse at room temperature for 2 hours to form a homogeneous solution. Then, spray 20 μL of this solution evenly onto a 2 x 0.5 cm piece of carbon paper to form a working electrode. A Hg-HgO electrode was used as the reference electrode, nickel foam as the counter electrode, and 1 mol / L potassium hydroxide solution as the electrolyte at a flow rate of 20 rpm. Acetylene gas was introduced evenly at a rate of 20 mL / min.

[0058] The prepared catalyst was used for the electrocatalytic semi-hydrogenation of acetylene in an alkaline medium. The reaction conditions were: at room temperature and pressure, a three-electrode system with hydrophobic carbon paper coated with CuO / NC as the working electrode, a Hg-HgO electrode as the reference electrode, nickel foam as the counter electrode, and a 1 mol / L potassium hydroxide solution as the electrolyte. The electrochemical instrument used was a CS310M electrochemical workstation and a HP-901 gas chromatograph. Cyclic voltammetry, linear sweep voltammetry, and galvanostatic polarization were used to test the catalyst's hydrogenation performance in alkaline medium.

[0059] Example 4

[0060] Figure 1 This is the SEM image of the CuO / NC catalyst prepared in Example 1. It can be seen that the catalyst is in a dense flake shape, which proves that there are more active sites on the catalyst and it has higher activity. Figure 2 is the XRD pattern of the CuO / NC catalyst prepared in Example 1; Figure 2 It can be seen that the prepared catalyst is basically consistent with the CuO standard card, thus proving the successful preparation of the catalyst; Figure 3 This is the XPS spectrum of the CuO / NC catalyst prepared in Example 1. It can be seen from the figure that the prepared catalyst contains substances such as C, O, N, and Cu, which can prove that the catalyst was successfully prepared.

[0061] Example 5

[0062] Figure 4 1 is the linear sweep voltammetry curve of the CuO / NC catalyst prepared in Example 1 under acetylene gas and argon atmospheres. It can be seen that the catalyst has a larger current density under acetylene gas atmosphere. Figure 5 1 is the Faradaic efficiency and selectivity diagram of the CuO / NC catalyst prepared in Example 1 in acetylene gas. It can be seen that the catalyst still has high Faradaic efficiency and stability under large current.

[0063] Example 6

[0064] Table 1 Performance test results of CuO / NC catalyst in Example 1

[0065]

[0066] Table 1 shows the catalyst in Example 1 at 0.1-1.0 A / cm 2 Performance test under current density. It can be seen from this table that the catalyst in this embodiment has a current density of 1.0A / cm 2 The Faradaic efficiency of 80-85% and the conversion rate of 90-95% are still maintained at a high current density.

[0067] Table 2 Performance test results of CuO / NC catalyst in Example 2

[0068]

[0069]

[0070] Table 2 shows the catalyst in Example 2 at 0.1-1.0 A / cm 2 Performance test under current density. It can be seen from this table that the catalyst in this embodiment has a current density of 1.0A / cm 2 The Faradaic efficiency of 75-80% and the conversion rate of 85-90% are still maintained at a high current density.

[0071] Table 3 Performance test results of CuO / NC catalyst in Example 3

[0072]

[0073]

[0074] Table 3 shows the catalyst in Example 3 at 0.1-1.0 A / cm 2 Performance test under current density. It can be seen from this table that the catalyst in this embodiment has a current density of 1.0A / cm 2 The Faradaic efficiency of 75-80% and the conversion rate of 90-95% are still maintained at a high current density.

[0075] Table 4 Test results of C2H2 electrocatalytic semi-hydrogenation performance of catalysts

[0076]

[0077] Table 4 shows the test results of the electrocatalytic semi-hydrogenation performance of existing catalysts and the CuO / NC catalyst of the present invention for C2H2. It can be seen that the catalyst of the present invention is much higher in selectivity than other catalysts and has a higher Faraday efficiency.

Claims

1. A method for preparing a CuO active site modified nitrogen-doped porous carbon catalyst, characterized in that: Using copper salt and benzenetricarboxylic acid as raw materials, and then adding a nitrogen source precursor, N / Cu-MOF was prepared by a hydrothermal method; then it was etched and oxidized with potassium hydroxide solution to finally obtain a CuO active site modified nitrogen-doped porous carbon catalyst.

2. The method for preparing the CuO active site modified nitrogen-doped porous carbon catalyst according to claim 1, wherein: Please follow the steps below to implement it: Step 1, synthesis of nitrogen-doped copper-based metal organic framework compounds; specifically: Step 1.1, dissolving a copper salt in N,N-dimethylformamide to obtain a copper salt solution; dissolving benzenetricarboxylic acid in N,N-dimethylformamide to obtain a benzenetricarboxylic acid solution; mixing the copper salt solution with a nitrogen source precursor, stirring uniformly, adding the benzenetricarboxylic acid solution, and stirring uniformly to obtain a precursor mixture; Step 1.2, placing the precursor mixture obtained in step 1.1 in a high-pressure reactor for hydrothermal reaction, centrifuging after the reaction, washing with N,N-dimethylformamide and anhydrous ethanol several times in sequence, and vacuum drying to obtain a nitrogen-doped copper-based metal organic framework compound; Step 2: dissolving the nitrogen-doped copper-based metal organic framework compound in water, ultrasonically stirring, then adding potassium hydroxide solution and stirring to react. After the reaction is completed, centrifuging, washing with water and ethanol several times in sequence, and freeze-drying to obtain a CuO active site modified nitrogen-doped porous carbon catalyst.

3. The method for preparing the CuO active site modified nitrogen-doped porous carbon catalyst according to claim 2, wherein: In the step 1.1, the mass ratio of copper salt, benzenetricarboxylic acid and nitrogen source precursor is 0.3-1.5:0.1-0.8:0.1-0.5; the copper salt is any one of copper nitrate, copper sulfate, copper carbonate and copper chloride; and the nitrogen source precursor is any one of polyvinylpyrrolidone, melamine and pyrazole.

4. The method for preparing the CuO active site modified nitrogen-doped porous carbon catalyst according to claim 2, wherein: In the step 1.2, the hydrothermal reaction time is 10 to 36 hours, the hydrothermal reaction temperature is 50 to 120° C.; the centrifugal speed is 5000 to 10000 rpm, and the centrifugal time is 3 to 20 minutes; the vacuum drying temperature is 30 to 80° C., and the drying time is 8 to 36 hours.

5. The method for preparing the CuO active site modified nitrogen-doped porous carbon catalyst according to claim 2, wherein: In step 2, the mass ratio of the nitrogen-doped copper-based metal organic framework compound to water is 0.1-1:5-10; and the concentration of the potassium hydroxide solution is 0.5-3 mol / L.

6. The method for preparing the CuO active site modified nitrogen-doped porous carbon catalyst according to claim 2, wherein: In step 2, the stirring reaction time is 5 to 12 hours, the stirring rate is 1000 to 5000 rpm; the centrifugal rate is 5000 to 10000 rpm, and the centrifugal time is 3 to 20 minutes; the freeze-drying temperature is -30 to -80°C, and the freeze-drying time is 12 to 36 hours.

7. The nitrogen-doped porous carbon catalyst prepared by the method for preparing a CuO active site modified nitrogen-doped porous carbon catalyst according to any one of claims 1 to 6.

8. Use of the CuO active site modified nitrogen-doped porous carbon catalyst according to any one of claims 1 to 6 in the electrocatalytic acetylene semi-hydrogenation reaction.

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