Green and efficient method for electrochemically synthesizing olefin by transferring hydrogen atoms in water through electrocatalysis

Abstract

The invention relates to a green and efficient method for electrochemically synthesizing olefin by electrocatalyzing transfer of hydrogen atoms in water, which comprises the following steps: by taking cheap chemicals alkyne and water as raw materials, Pd TpBpy-SH with a large specific surface area as an electrocatalyst and electric energy as an energy source, promoting water splitting of hydrogen atoms in the water to be transferred to alkyne to synthesize an olefin compound; the synthesis method has the advantages of atom economy, simple steps, high efficiency, green and environment-friendly synthesis route so as to meet the requirements of industrial application, and the synthesis method is greener, more environment-friendly and wide in application range.

Description

Technical Field

[0001] The present invention relates to a method for electrochemically synthesizing olefins by green and efficient electrocatalytic hydrogen atom transfer in water, belonging to the technical field of electrochemical heterogeneous catalysis. Background Art

[0002] As a key basic chemical raw material in the petrochemical industry, olefins have extremely wide downstream applications and play an important role in the synthesis of fine chemicals, advanced materials, drugs and spices. Therefore, the demand for olefins has been increasing year by year. The chemoselective semi-hydrogenation reaction of alkynes is one of the important reactions for synthesizing olefins. In the past decade or so, numerous innovative catalytic methods have been developed to solve the problem of selective hydrogenation of alkynes.

[0003] Traditional thermal catalytic selective hydrogenation of alkynes has been widely used in both the petrochemical and fine chemical industries. However, for different alkyne hydrogenation reactions, the required reaction conditions and catalysts are different. Most thermal catalytic alkyne hydrogenation reactions have a reaction temperature range between 45 and 250 °C, and an excessive amount of H 2 needs to be added as a hydrogen source and selective hydrogenation is carried out within an appropriate pressure range. H 2 As a flammable gas, the safety during transportation and reaction has raised concerns. In addition, in such reactions, over-hydrogenation reactions often occur, generating alkane by-products, resulting in poor selectivity for the target olefin; at the same time, the cracking of alkynes and their intermediates to form coke is also one of the side reactions of thermal catalytic hydrogenation. These problems not only reduce the selectivity of the target olefin, but also the substances such as oligomers and coke produced have a serious impact on actual production. Therefore, there is an urgent need to develop catalysts that can effectively inhibit the side reactions of alkyne semi-hydrogenation and a safe, efficient and green alkyne semi-hydrogenation method.

[0004] The electrochemical semi-hydrogenation of alkynes uses the active hydrogen in-situ generated from water, providing a safe, sustainable and environmentally friendly alternative to traditional hydrogenation processes. The earliest electrochemical hydrogenation of alkynes can be traced back to 1943, but at that time, due to problems such as low reaction current density, poor olefin selectivity and low alkyne conversion rate, it could not be compared with traditional thermal catalytic alkyne hydrogenation, restricting the development of electrocatalytic alkyne hydrogenation.

[0005] In recent years, with the rapid development of material synthesis technology and reaction devices, electrocatalytic alkyne hydrogenation reactions have come back into the spotlight. Compared with traditional thermal catalytic hydrogenation, electrocatalytic alkyne hydrogenation has the following advantages: Firstly, electrochemical hydrogenation can be carried out at room temperature and atmospheric pressure, reducing energy consumption and improving the stability of the hydrogenation process; Secondly, the driving force of electrocatalysis comes from green renewable electric energy, and at the same time, it can alleviate the problem of abandoned wind power; Thirdly, water is selected as the hydrogen source, avoiding the problems of hydrogen storage and excessive hydrogen consumption, and reducing the potential safety hazards in production.

[0006] Pd-based catalysts have become the preferred catalysts for alkyne hydrogenation due to their large atomic utilization rate, isolated and uniform active sites, and excellent ability to adsorb and store active hydrogen. However, the activity of Pd catalysts is often too high, resulting in over-catalytic reactions and the formation of alkane by-products. Therefore, it is necessary to carefully design the electronic state of Pd in the palladium-based catalyst to enhance the activity and selectivity. A typical example is the Lindlar catalyst, which uses CaCO 3 as a carrier and adds several modifiers (usually lead acetate) to inhibit over-hydrogenation. However, this strategy of enhancing selectivity comes at the cost of activity and introduces toxic substances, which is prone to causing pollution. Therefore, in addition to the metal catalytic center, choosing a suitable catalytic carrier is still crucial, as it can immobilize metal nanoparticles and change their dispersion ability and electronic effects. As is well known, covalent organic frameworks (COFs) are an emerging class of porous crystalline organic catalytic carrier materials that show considerable potential applications in catalysis due to their many advantages, such as a suitable surface area, regular porosity, structural uniformity, and designability. Various researchers have developed many strategies to anchor metal nanoparticles on COF materials, which show excellent activity in catalytic reactions.

[0007] However, the research on metal-modified COF materials in the field of electrocatalytic hydrogenation reactions is still scarce. Given the continuous growth of the market demand for olefins and related high-value chemicals, it is urgent to develop more environmentally friendly and sustainable new electrochemical catalytic hydrogenation reactions. Summary of the Invention

[0008] Aiming at the deficiencies of the existing technology, especially the problems of complex reaction systems and operations, narrow application scope, serious over-hydrogenation, and environmental unfriendliness in the existing catalytic systems, the present invention provides a method for electrochemically synthesizing olefins by green and efficient electrocatalytic hydrogen atom transfer in water. Overview of the Invention:

[0010] The method of the present invention uses inexpensive chemicals, alkynes and water, as raw materials, uses Pd TpBpy-SH as an electrocatalyst, and uses electric energy as the energy source to promote water splitting. The generated active hydrogen is transferred to alkynes to synthesize olefins, which has an atomically economical, step-simple, low-cost, highly efficient, and green and environmentally friendly synthesis route to meet the requirements of industrial applications. The synthesis method of the present invention is more green, environmentally friendly, and has a wide application scope. Detailed Description of the Invention:

[0012] The present invention is realized through the following technical solutions:

[0013] A green and efficient method for electrocatalytic hydrogen atom transfer in water for electrochemical synthesis of olefins. This method uses chemical alkyne and water as raw materials, Pd TpBpy-SH as an electrocatalyst, and electric energy as the energy source to promote water splitting. The generated active hydrogen is transferred to the alkyne to synthesize olefins. The steps are as follows:

[0014] In an electrolytic cell separated by a Nafion117 anion exchange membrane, a solvent, an electrolyte, an alkyne, a cathode, an anode, and a reference electrode are added in sequence, stirred at room temperature, and the reaction is carried out under a constant voltage condition. The cathode is a carbon paper loaded with Pd TpBpy-SH electrocatalyst, the anode is a platinum sheet, and the reference electrode is a mercury / mercuric oxide electrode.

[0015] Preferably according to the present invention, the carbon paper loaded with Pd TpBpy-SH electrocatalyst is prepared by the following method:

[0016] (1) Dissolve phloroglucinol trialdehyde and 5,5'-diamino-2,2'-bipyridine in a mixed solvent of N,N-dimethylacetamide and 1,2-dichlorobenzene, add acetic acid solution, disperse by ultrasonic, perform freeze-pump cycles, heat in an oven, react, wash, filter, dry, and grind to obtain TpBpy COF catalyst;

[0017] (2) Disperse TpBpy COF catalyst and palladium acetate in dichloromethane, stir under a nitrogen atmosphere, filter, and dry in vacuo to obtain Pd-TpBpy COF loaded with metallic palladium; then dissolve Pd-TpBpy COF loaded with metallic palladium and β-mercaptoethylamine in a mixed solvent of absolute ethanol and water, stir, filter, dry in vacuo, and grind to obtain Pd TpBpy-SH catalyst;

[0018] (3) Disperse Pd TpBpy-SH catalyst, conductive carbon black, and polyvinylidene fluoride binder in N-methylpyrrolidone, mix evenly, and coat on carbon fiber paper to obtain the carbon paper loaded with Pd TpBpy-SH electrocatalyst.

[0019] Preferably according to the present invention, in step (1), the molar ratio of phloroglucinol trialdehyde to 5,5'-diamino-2,2'-bipyridine is (1-3):(2-5).

[0020] Most preferably, in step (1), the molar ratio of phloroglucinol trialdehyde to 5,5'-diamino-2,2'-bipyridine is 2:3.

[0021] Preferably according to the present invention, in step (1), the volume ratio of N,N-dimethylacetamide to 1,2-dichlorobenzene is (2-6):1.

[0022] Most preferably, in step (1), the volume ratio of N,N-dimethylacetamide to 1,2-dichlorobenzene is 3:1.

[0023] Preferably according to the present invention, in step (1), the mass-volume ratio of phloroglucinol trialdehyde to the mixed solvent is (18-25):(1-5), unit, mg / mL.

[0024] Preferably according to the present invention, in step (1), the concentration of the acetic acid solution is 4-8M, and the volume ratio of the acetic acid solution to the mixed solvent is (0.1-0.5):(1-5).

[0025] Preferably according to the present invention, in step (1), the heating reaction temperature is 110-140 °C and the reaction time is 3-5 days.

[0026] Preferably according to the present invention, in step (2), the mass ratio of TpBpy COF to palladium acetate is (0.8-1):1.

[0027] Preferably according to the present invention, in step (2), the mass-volume ratio of palladium acetate to dichloromethane is (2-3):1, unit mg / mL.

[0028] Preferably according to the present invention, in step (2), the mass ratio of Pd TpBpy COF loaded with metallic palladium to β-mercaptoethylamine is (40-60):(180-200).

[0029] Preferably according to the present invention, in step (2), the molar ratio of β-mercaptoethylamine to palladium acetate is (8-12):1.

[0030] Most preferably, in step (2), the molar ratio of β-mercaptoethylamine to palladium acetate is 10:1.

[0031] Preferably according to the present invention, in step (2), the volume ratio of absolute ethanol to water is (2-6):1.

[0032] Preferably according to the present invention, in step (2), the mass-volume ratio of β-mercaptoethylamine to the mixed solvent is (180-200):(8-20), unit, mg / mL.

[0033] Preferably according to the present invention, in step (3), the mass ratio of Pd TpBpy-SH electrocatalyst, conductive carbon black, and polyvinylidene fluoride binder is (4-10):(1-3):(1-3).

[0034] Preferably according to the present invention, in step (3), the mass-volume ratio of Pd TpBpy-SH electrocatalyst to N-methylpyrrolidone is (1-2):(80-100), unit mg / μL.

[0035] Preferably, in the method for synthesizing an olefin compound:

[0036] Preferably according to the present invention, the electrolyte is potassium hydroxide, the solvent is a mixed solution of an organic solvent and water, and the organic solvent is 1,4-dioxane.

[0037] Preferably according to the present invention, the volume ratio of dioxane to water is (4 - 6):(6 - 4), in units of mL.

[0038] Preferably according to the present invention, the solvent, electrolyte, and alkyne are uniformly mixed to form a mixed solution, and the concentration of the electrolyte in the mixed solution is 0.3 - 0.6 M.

[0039] Preferably according to the present invention, the solvent, electrolyte, and alkyne are uniformly mixed to form a mixed solution, and the concentration of the alkyne in the mixed solution is 8 - 12 mM.

[0040] The present invention uses water as a raw material and Pd TpBpy-SH as an electrocatalyst. Water provides a hydrogen source. When water is activated and decomposed on Pd TpBpy-SH to form a hydrogen-containing intermediate, this intermediate acts as an active species to selectively hydrogenate alkynes to olefin compounds with a high yield of olefin compounds. Excessive or too little water content will lead to a decrease in the yield.

[0041] Preferably according to the present invention, the alkyne is 4-biphenylacetylene, and its structural formula is shown as the following formula I:

[0042]

[0043] Preferably according to the present invention, the reaction temperature is 20 - 30 °C, and the reaction time is 8 - 12 hours.

[0044] Preferably according to the present invention, the magnitude of the applied voltage is 1.1 - 1.4 V.

[0045] Preferably according to the present invention, the reaction is carried out in an air environment.

[0046] The present invention uses inexpensive chemical alkynes and water as raw materials, uses Pd TpBpy-SH with an easily designed structure as an electrocatalyst, uses electrical energy as an energy source to promote water splitting, and the generated hydrogen atoms are transferred to alkynes to synthesize olefin compounds. The obtained olefin structure is shown as formula II:

[0047]

[0048] The reaction route of the present invention is as follows:

[0049]

[0050] The technical features and advantages of the present invention:

[0051] 1. The method of the present invention uses inexpensive chemicals, alkynes and water, as raw materials, and uses Pd TpBpy-SH with an easily designed structure as an electrocatalyst. With electrical energy as the energy source, it promotes water splitting, and the generated oxygen atoms are transferred to alkynes to synthesize olefin compounds. It has an atomically economical, step-simple, low-cost, highly efficient, green and environmentally friendly synthesis route to meet the requirements of industrial applications. The synthesis method of the present invention is more green, environmentally friendly and has a wide range of applications.

[0052] 2. The present invention adopts an electrochemical method for synthesizing olefin compounds. This method avoids the use of toxic and harmful regulators such as lead acetate and quinoline and dangerous chemicals such as flammable gas hydrogen, will not cause safety problems and harmful waste residue problems, is easy to operate, has a considerable yield, is environmentally friendly, and has good application prospects.

[0053] 3. The present invention uses water as the raw material and Pd TpBpy-SH as the electrocatalyst. Water provides a hydrogen source. When water is activated and decomposed on Pd TpBpy-SH to form a hydrogen-containing intermediate, this intermediate selectively hydrogenates alkynes to olefin compounds as an active species. The olefin yield is high. It not only avoids the use of flammable gas hydrogen, greatly reduces the reaction cost, but also has the advantages of simple and safe operation; it saves costs and also avoids environmental pollution caused by lead-containing waste. Description of the Drawings

[0054] Figure 1 SEM image of the Pd TpBpy-SH electrocatalyst prepared in Example 1 of the present invention.

[0055] Figure 2 TEM image of the Pd TpBpy-SH electrocatalyst prepared in Example 1 of the present invention.

[0056] Figure 3 FT-IR image of the Pd TpBpy-SH electrocatalyst prepared in Example 1 of the present invention.

[0057] Figure 4 TEM Mapping image of the Pd TpBpy-SH electrocatalyst prepared in Example 1 of the present invention.

[0058] Figure 5 Standard curve used for the quantification of the remaining substrate of the present invention.

[0059] Figure 6 Standard curve used for the quantification of the product formation of the present invention.

[0060] Figure 7 Standard curve used for the quantification of the by-product formation of the present invention

[0061] Figure 8 Mass spectra of the substrate, product and by-products of the present invention. Detailed implementation mode

[0062] The following further illustrates the content of the present invention through specific examples, but does not limit the present invention.

[0063] The raw materials used in the examples can be purchased on the market or prepared according to the existing technology.

[0064] Example 1:

[0065] The preparation method of the Pd TpBpy-SH electrocatalyst is as follows:

[0066] (1) Add 21 mg of phloroglucinol trialdehyde and 27.9 mg of 5,5'-diamino-2,2'-bipyridine into a Schlenk tube, then add 1.5 mL of DMAc and 0.5 mL of o-DCB, and then add 0.2 mL of 6 M acetic acid, and disperse evenly by ultrasonic. Under the condition of liquid nitrogen, after three freeze-thaw-pump-thaw cycles, seal it and put it into an oven at 120 °C for 72 h. Wait for it to naturally cool to room temperature, and perform Soxhlet extraction with DMAc, H 2 O, and acetone, and vacuum dry at 60 °C to obtain TpBpy COF.

[0067] (2) Take 50 mg of TpBpy COF and 56 mg of palladium acetate and disperse them in 28 mL of dichloromethane, stir for 6 h under a nitrogen atmosphere, filter and wash, and vacuum dry at 60 °C to obtain Pd TpBpy COF loaded with palladium metal. Dissolve 50 mg of Pd TpBpy COF and 193 mg of β-mercaptoethylamine in a mixed solution of anhydrous ethanol (6 mL) and water (2 mL), stir at 30 °C for 6 h, filter and wash, vacuum dry, and grind to obtain the Pd TpBpy-SH catalyst;

[0068] The SEM image and TEM image of the Pd TpBpy-SH catalyst prepared in this example are shown in Figure 1 、 Figure 2 . It can be seen from the SEM image that the prepared sample presents a rod-like structure. The TEM image shows that palladium metal is evenly dispersed.

[0069] The infrared spectrum and TEM Mapping of the Pd TpBpy-SH catalyst prepared in this example are shown in Figure 3 、 Figure 4 . The infrared spectrum shows the presence of the C-N bond of the catalyst, indicating the successful synthesis of the catalyst skeleton. TEM Mapping shows the uniform dispersion of various elements of the catalyst and the successful coordination of sulfur, further proving the successful synthesis of the catalyst.

[0070] Example 2:

[0071] Preparation of Carbon Paper Loaded with Pd TpBpy-SH Electrocatalyst:

[0072] 5 mg of the Pd TpBpy-SH catalyst prepared in Example 1, conductive carbon black, and polyvinylidene fluoride binder were dispersed in 500 μL of N-methylpyrrolidone in a mass ratio of 5:1:1, and mixed evenly to obtain a slurry. The slurry was coated on carbon fiber paper and dried to obtain carbon paper loaded with Pd TpBpy-SH electrocatalyst.

[0073] Example 3:

[0074] Electrocatalytic Alkyne Hydrogenation Reaction:

[0075] 5 mL of dioxane, 5 mL of 1 M potassium hydroxide aqueous solution, and 0.1 mmol of 4-stilbene were successively added to a divided cell separated by a Nafion 117 ion membrane. The carbon paper loaded with Pd TpBpy-SH electrocatalyst prepared in Example 2 was used as the anode, and a platinum sheet electrode was used as the cathode. Under air conditions at 25 °C, with a constant voltage of 1.1 V, the reaction was carried out for 12 h. Using water as the raw material, water was electrolyzed, and the generated oxygen atoms were transferred to alkynes to synthesize olefin compounds.

[0076] Comparative Example 1

[0077] The electrocatalytic alkyne hydrogenation reaction method described in Example 3 was used, except that:

[0078] The water content was reduced to 4 mL, and the volume ratio of water to dioxane was 4:6. With other condition parameters unchanged, the operation was carried out according to Example 3.

[0079] Comparative Example 2

[0080] The electrocatalytic alkyne hydrogenation reaction method described in Example 3 was used, except that:

[0081] The water content was increased to 6 mL, and the volume ratio of water to dioxane was 6:4. With other condition parameters unchanged, the operation was carried out according to Example 3.

[0082] Comparative Example 3

[0083] The electrocatalytic alkyne hydrogenation reaction method described in Example 3 was used, except that:

[0084] Carbon fiber paper was used as the working electrode. With other condition parameters unchanged, the operation was carried out according to Example 3.

[0085] Comparative Example 4

[0086] The electrocatalytic alkyne hydrogenation reaction method described in Example 3 was used, except that:

[0087] Using carbon paper loaded with TpBpy COF as the working electrode, with other condition parameters unchanged, conduct the experiment according to Example 3.

[0088] Comparative Example 5

[0089] The electrocatalytic alkyne hydrogenation reaction method is the same as that described in Example 3, except that:

[0090] Using carbon paper loaded with Pd TpBpy COF as the working electrode, with other condition parameters unchanged, conduct the experiment according to Example 3.

[0091] Comparative Example 6

[0092] The electrocatalytic alkyne hydrogenation reaction method is the same as that described in Example 3, except that:

[0093] Using carbon paper as the working electrode, adding 5 mg of palladium acetate, with other condition parameters unchanged, conduct the experiment according to Example 3.

[0094] Comparative Example 7

[0095] The electrocatalytic alkyne hydrogenation reaction method is the same as that described in Example 3, except that:

[0096] The voltage is -0.9 V, with other condition parameters unchanged, conduct the experiment according to Example 3.

[0097] Comparative Example 8

[0098] The electrocatalytic alkyne hydrogenation reaction method is the same as that described in Example 3, except that:

[0099] The voltage is -1.0 V, with other condition parameters unchanged, conduct the experiment according to Example 3.

[0100] Comparative Example 9

[0101] The electrocatalytic alkyne hydrogenation reaction method is the same as that described in Example 3, except that:

[0102] The voltage is -1.2 V, with other condition parameters unchanged, conduct the experiment according to Example 3.

[0103] Comparative Example 10

[0104] The electrocatalytic alkyne hydrogenation reaction method is the same as that described in Example 3, except that:

[0105] The voltage is -1.3 V, with other condition parameters unchanged, conduct the experiment according to Example 3.

[0106] Comparative Example 11

[0107] The electrocatalytic alkyne hydrogenation reaction method is the same as that described in Example 3, except that:

[0108] Replace the cathode with carbon paper loaded with Pd TpBpy-thiol, and keep other condition parameters unchanged, and carry out according to Example 3.

[0109] The preparation of carbon paper loaded with Pd TpBpy-thiol was carried out according to Example 2. The PdTpBpy-SH catalyst was replaced with Pd-TpBpy-thiol, and Pd TpBpy-thiol was prepared according to Example 1, except that β-mercaptoethylamine was replaced with propanethiol, and the other parameters remained unchanged.

[0110] Test Example

[0111] Test the conversion rate and selectivity of Example 3 and Comparative Examples 1-11, as shown in Table 1 below:

[0112] Table 1

[0113]

[0114] It can be seen from Table 1 above that the water content, the type of cathode electrode, and the electrochemical reaction voltage all affect the product conversion rate and selectivity. If the water content is too high or too low, the substrate conversion rate will decrease. Changing the type of cathode electrode will lead to a decrease in the yield or no reaction. Both decreasing or increasing the voltage will result in a decrease in the conversion rate or selectivity. In summary, the present invention controls the water content, the type of cathode electrode, and the electrochemical reaction voltage, uses Pd TpBpy-SH with a large specific surface area as an electrocatalyst, uses electric energy as an energy source, promotes water splitting, and the generated hydrogen atoms are transferred to alkynes to synthesize olefin compounds. It has atom economy, simplicity of steps, high efficiency, and a green and environmentally friendly synthesis route to meet the requirements of industrial applications. The synthesis method of the present invention is more green, environmentally friendly, and has a wide range of applications.

Claims

1. A green and efficient electrocatalytic method for electrochemically synthesizing olefins by hydrogen atom transfer in water, which uses chemical alkynes and water as raw materials, uses Pd TpBpy-SH as an electrocatalyst, uses electrical energy as an energy source, promotes water splitting, and transfers the generated active hydrogen to alkynes to synthesize olefins, and the steps are as follows: Solvent, electrolyte, alkyne, cathode, anode and reference electrode were sequentially added to an electrolytic cell separated by a Nafion117 anion membrane, stirred at room temperature, and reacted under constant voltage conditions. The cathode was carbon paper loaded with Pd TpBpy-SH electrocatalyst, the anode was a platinum sheet, and the reference electrode was a mercury / mercury oxide electrode.

2. The method according to claim 1, characterized in that The carbon paper loaded with Pd TpBpy-SH electrocatalyst was prepared as follows: (1) dissolving trialdehyde phloroglucinol and 5,5'-diamino-2,2'-bipyridine in a mixed solvent of N,N-dimethylacetamide and 1,2-dichlorobenzene, adding acetic acid solution, performing ultrasonic dispersion, freeze-pump cycle, oven heating reaction, washing, filtering and drying, and grinding to obtain TpBpy COF catalyst; (2) dispersing the TpBpy COF catalyst and palladium acetate in dichloromethane, stirring under a nitrogen atmosphere, filtering, and vacuum drying to obtain Pd-TpBpy COF loaded with metal palladium; then dissolving the Pd-TpBpy COF loaded with metal palladium and β-mercaptoethylamine in a mixed solvent of anhydrous ethanol and water, stirring, filtering, vacuum drying, and grinding to obtain a Pd TpBpy-SH catalyst; (3) The Pd TpBpy-SH catalyst, conductive carbon black, and polyvinylidene fluoride binder are dispersed in N-methylpyrrolidone, mixed evenly, and coated on carbon fiber paper to obtain carbon paper loaded with Pd TpBpy-SH electrocatalyst.

3. The method according to claim 2, characterized in that In step (1), the molar ratio of trialdehyde phloroglucinol to 5,5'-diamino-2,2'-bipyridine is (1-3):(2-5), and the volume ratio of N,N-dimethylacetamide to 1,2-dichlorobenzene is (2-6):

1.

4. The method according to claim 2, characterized in that: In step (1), the mass volume ratio of trialdehyde phloroglucinol to the mixed solvent is (18-25): (1-5), the unit is mg / mL, the concentration of the acetic acid solution is 4-8M, the volume ratio of the acetic acid solution to the mixed solvent is (0.1-0.5): (1-5), the heating reaction temperature is 110-140°C, and the reaction time is 3-5 days.

5. The method according to claim 2, characterized in that: In step (2), the mass ratio of TpBpy COF to palladium acetate is (0.8-1):1, the mass volume ratio of palladium acetate to dichloromethane is (2-3):1, the unit is mg / mL, the mass ratio of Pd-TpBpy COF loaded with metal palladium to β-mercaptoethylamine is (40-60):(180-200), and the molar ratio of β-mercaptoethylamine to palladium acetate is (8-12):

1.

6. The method according to claim 2, characterized in that In step (2), the volume ratio of anhydrous ethanol to water is (2-6):1, and the mass volume ratio of β-mercaptoethylamine to the mixed solvent is (180-200):(8-20), in units of mg / mL.

7. The method according to claim 2, characterized in that In step (3), the mass ratio of Pd TpBpy-SH electrocatalyst, conductive carbon black and polyvinylidene fluoride binder is (4-10): (1-3): (1-3), and the mass volume ratio of Pd TpBpy-SH electrocatalyst and nitrogen methyl pyrrolidone is (1-2): (80-100), unit: mg / μL.

8. The method according to claim 1, characterized in that The electrolyte is potassium hydroxide, the solvent is a mixed solution of an organic solvent and water, and the organic solvent is 1,4-dioxane.

9. The method according to claim 1, characterized in that: The volume ratio of dioxane to water is (4-6):(6-4), unit: mL.

10. The method according to claim 1, characterized in that The solvent, electrolyte and alkyne are mixed evenly to form a mixed solution, wherein the concentration of the electrolyte in the mixed solution is 0.3-0.6M. The solvent, electrolyte and alkyne are mixed evenly to form a mixed solution, wherein the concentration of the alkyne in the mixed solution is 8-12mM.

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