A binuclear copper coordination polymer material for membrane electrode electrocatalytic hydrogenation and a preparation method thereof

Abstract

The application provides a binuclear copper coordination polymer material for membrane electrode electrocatalytic hydrogenation and a preparation method thereof, and solves the problems of high cost, easy production of hydrogen by-product and difficulty in large-scale application of existing membrane electrode electrolytic catalytic hydrogenation materials. First, an imidazole salt containing a dicarboxyl group is used as a ligand, a mononuclear copper coordination polyimidazole salt is generated by direct action of the carboxyl group in the ligand and a copper salt through a solvothermal method, and then a binuclear copper coordination polymer material is successfully prepared by introducing a copper site through a metal post-modification method. The binuclear copper coordination polymer material is more conducive to enhancing the electron donor-acceptor effect to promote acetylene activation semi-hydrogenation due to its electronic properties different from the mononuclear copper site, has excellent membrane cell electrocatalytic hydrogenation performance, and can be applied as a catalytic hydrogenation material.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of membrane electrode electrocatalytic materials, and particularly relates to a binuclear copper coordination polymer material for membrane electrode electrocatalytic hydrogenation and a preparation method thereof. BACKGROUND

[0002] Ethylene is an important raw material in the chemical industry, which is currently mainly produced by high-temperature naphtha cracking process. Due to the limited oil reserves in China and the low self-sufficiency rate of crude oil, it is urgent to seek a method of producing ethylene independent of oil. In view of the resource endowment of more coal and less oil in China, producing ethylene by coal-to-acetylene (15vol.%) and then acetylene hydrogenation is a promising approach. In combination with the national strategic goal of "carbon peak and carbon neutralization", developing an electrocatalytic acetylene hydrogenation system with water as the hydrogen source has important application value for the green and clean development and high-value utilization of coal-to-acetylene.

[0003] As the most common device for electrocatalytic acetylene hydrogenation reaction at present, the liquid flow type electrolytic cell has shown good ethylene selectivity and current density, but there are still problems such as electrolyte overflow, gas diffusion layer blockage, high applied cell voltage and high energy consumption, which need to be solved urgently.

[0004] In contrast, the cathode of the membrane electrode electrolytic cell is free of electrolyte, and the reaction gas with a certain humidity directly reacts with the catalytic material through the gas diffusion layer, effectively avoiding the problems of electrolyte overflow and gas diffusion layer blockage. At the same time, the distance between the anode and the cathode in the membrane electrode electrolytic cell is short, which can significantly reduce the impedance loss, and thus reduce the applied voltage and energy consumption. So far, the membrane electrode electrocatalytic acetylene hydrogenation material is mainly a palladium-based material, but its high cost hinders its large-scale application; at the same time, the palladium-based catalytic material is easy to combine with active hydrogen, thereby producing hydrogen evolution by-product, which reduces the selectivity of electrocatalytic acetylene hydrogenation.

[0005] Therefore, it is necessary to explore a new membrane electrode electrocatalytic hydrogenation material. SUMMARY

[0006] The purpose of the present application is to solve the problems of high cost, easy production of hydrogen evolution by-product and difficulty in large-scale application of the existing membrane electrode electrolytic catalytic hydrogenation material, and to provide a binuclear copper coordination polymer material for membrane electrode electrocatalytic hydrogenation and a preparation method thereof. Under industrial current, whether using a flow type electrolytic cell or a membrane electrode electrolytic cell, it has excellent electrocatalytic acetylene hydrogenation performance and can effectively inhibit the hydrogen evolution by-product.

[0007] The idea of the present application is:

[0008] In order to reduce the cost of catalysis and the generation of hydrogen by-product, the research direction of the present application focuses on the development of non-noble metal hydrogenation catalytic materials. The copper-based coordination polymer material has the advantages of high porosity, abundant raw materials and good gas adsorption, and can combine the moderate affinity of copper sites to active hydrogen, which is expected to reduce the cost of catalysis while avoiding the generation of hydrogen by-product. It is worth noting that the research team found that the dinuclear copper site has different electronic properties from the mononuclear copper site, which is more conducive to enhancing the electron donation effect to promote the activation of acetylene semi-hydrogenation. Therefore, the present application intends to select a dinuclear copper coordination polymer material as a membrane electrode electrocatalytic hydrogenation material with high activity (i.e. low cell voltage) and high selectivity.

[0009] Based on the above inventive concept, in order to achieve the purpose of the present application, the technical solution provided by the present application is:

[0010] A preparation method of a dinuclear copper coordination polymer material for membrane electrode electrocatalytic hydrogenation, which is characterized by comprising the following steps:

[0011] 1) A dicarboxy-containing imidazole salt and a copper salt are weighed, an organic solvent A is added thereto, and after stirring and ultrasonic dispersion, a mixed solution is obtained;

[0012] The mixed solution is transferred to a reaction kettle for solvothermal reaction, and after the reaction is completed and cooled to room temperature, the reaction product is washed and vacuum filtered several times, and then the filtered solid is dried to obtain a mononuclear copper coordination polyimidazole salt;

[0013] 2) The mononuclear copper coordination polyimidazole salt obtained in step 1) and a copper salt are dispersed in an organic solvent B, and under inert gas and alkaline conditions, stirring is performed for reaction, and coordination with copper is performed by metal post-modification method. After the reaction is completed, the reaction product is washed and centrifuged several times, and then the centrifuged solid is dried to obtain a dinuclear copper coordination polymer material;

[0014] The base used in the alkaline condition is 1,8-diazabicyclo[5.4.0]undec-7-ene, potassium carbonate or potassium tert-butoxide.

[0015] Further, in step 1), the dicarboxy-containing imidazole salt is any one of 1,3-bis(4-carboxyphenyl)-halogenated imidazole salt, 1,3-bis[(4-carboxy-3',5'-diisopropyl)biphenyl]-halogenated imidazole salt, 4,7-bis(4-carboxyphenyl)-1,3-dimethylbenzimidazole halide salt or 3-[(4,4'-dicarboxy[1,1'-biphenyl]-2-yl)methyl]-1-methyl-1H-halogenated imidazole salt and its derivatives;

[0016] The copper salt is copper nitrate, copper halide or cuprous halide;

[0017] The organic solvent A is N, N-dimethylformamide, methanol, acetone, tetrahydrofuran or 1, 4-dioxane;

[0018] The molar ratio of the dicarboxy-containing imidazole salt to the copper salt is 1:1-1:1.5;

[0019] The ratio of the raw material to the organic solvent A is 1:125-250 mmol / mL, wherein the amount of the raw material refers to the total amount of the dicarboxy-containing imidazole salt and the copper salt;

[0020] The temperature of the solvothermal reaction is 120-160 DEG C, and the reaction time is 24-48 h.

[0021] Further, in step 2), the copper salt is copper nitrate, copper halide or cuprous halide;

[0022] The organic solvent B is tetrahydrofuran, methanol or acetone;

[0023] The molar ratio of the mononuclear copper-coordinated polyimidazole salt to the copper salt is 1:1-1:1.5;

[0024] The ratio of the raw material to the organic solvent B is 1:100-400 mmol / mL, wherein the amount of the raw material refers to the total amount of the mononuclear copper-coordinated polyimidazole salt and the copper salt;

[0025] The temperature of the reaction is 20-60 DEG C, and the reaction time is 24-48 h.

[0026] The inert gas is nitrogen or argon.

[0027] Meanwhile, the application also provides a binuclear copper-coordinated polymer material for membrane electrode electrocatalytic hydrogenation prepared by the aforementioned preparation method, and application of the binuclear copper-coordinated polymer material as a hydrogenation material in preparation of ethylene by membrane electrode electrocatalytic hydrogenation.

[0028] The molecular structure of the binuclear copper-coordinated polymer material is as follows:

[0029]

[0030] Wherein, the square represents an aromatic ring.

[0031] Based on the aforementioned application, the application provides a method for preparing ethylene by membrane electrode electrocatalytic hydrogenation, which is characterized in that the method comprises the following steps:

[0032] S1. The binuclear copper-coordinated polymer material prepared by the aforementioned preparation method is weighed as a cathode electrocatalytic hydrogenation material, a binder is added, and the mixture is uniformly dispersed in a volatile organic solvent C to obtain a cathode material slurry;

[0033] S2. The cathode material slurry obtained in S1 is uniformly coated on the gas diffusion layer (until the desired loading amount is reached), and after sufficient drying, the cathode is ready for use, i.e., the binuclear copper coordination polymer material serves as the cathode catalytic layer;

[0034] S3. The non-noble metal-based anode, the cathode obtained in S2, and an ion exchange membrane are assembled into a membrane electrode electrolysis cell to perform electrocatalytic ethyne hydrogenation reaction, thereby obtaining ethylene.

[0035] Further, in S1, the binder is a polytetrafluoroethylene emulsion, a perfluorosulfonic acid resin emulsion, or a fluorocarbon resin emulsion.

[0036] The organic solvent C is an easily volatile organic solvent such as isopropyl alcohol, ethanol, methanol, or acetone.

[0037] The use amount ratio of the binuclear copper coordination polymer material, the organic solvent C, and the binder is 1-100:5-20:10-500 (mg:mL:μL).

[0038] Further, in S2, the cathode material slurry is uniformly coated on the gas diffusion layer by spraying.

[0039] The gas diffusion layer is 5% polytetrafluoroethylene, which is placed on a flat material, and the flat material is made of carbon fiber paper, carbon fiber woven cloth, non-woven fabric, or carbon black paper.

[0040] Further, in S3, the non-noble metal-based anode is prepared by growing non-noble metal-based particles or alloys, oxides, hydroxides, or composites on the anode current collector by immersion or electrodeposition, i.e., the non-noble metal-based material serves as the anode catalytic layer; the non-noble metal is Fe, Co, or Ni.

[0041] The anode current collector is foamed nickel, copper mesh, titanium felt, carbon paper, or carbon cloth.

[0042] The wet ethyne raw material used is pure ethyne or a mixed gas of ethyne and other gases (such as inert gases or ethylene); the flow rate of the wet ethyne raw material used is 5-1000 sccm.

[0043] The anode electrolyte used is an acidic, neutral, or alkaline liquid electrolyte or a solid electrolyte, such as 0.01-5 M hydrochloric acid, 0.01-5 M sulfuric acid, 0.01-5 M KCl solution, 0.01-10 M KHCO3 solution, or 0.01-10 M KOH solution; the flow rate of the anode electrolyte used is 5-200 sccm.

[0044] Further, in S3, the wet ethyne raw material enters from the gas hole inlet of the cathode, and the corresponding product is collected from the gas hole outlet; at the same time, a peristaltic pump is used to promote the circulation of the anode electrolyte in the anode hole.

[0045] Principles of the present application:

[0046] The present application first uses dicarboxy-containing imidazole salt as ligand, and then uses solvent thermal method and metal post-modification method to successfully prepare binuclear copper coordination polymer material. The binuclear copper coordination polymer material has excellent membrane electrode electrocatalytic hydrogenation performance, and can realize efficient electrocatalytic ethylene production from acetylene in a membrane electrode electrolysis cell.

[0047] Advantages of the present application:

[0048] 1. The present application uses dicarboxy-containing imidazole salt as ligand, and then uses solvent thermal method and metal post-modification method to successfully prepare binuclear copper coordination polymer material. The material has excellent membrane electrode electrocatalytic hydrogenation performance, and can realize efficient electrocatalytic ethylene production from acetylene in a membrane electrode electrolysis cell.

[0049] 2. The binuclear copper coordination polymer material obtained in the present application is used as a cathode catalytic layer, a non-noble metal-based material is used as an anode catalytic layer, and a gas diffusion layer and an ion exchange membrane are assembled into a membrane electrode electrolysis cell for electrocatalytic acetylene hydrogenation performance test. Test results show that when a simulated coal acetylene gas stream (15vol.%) is used, the binuclear copper coordination polymer material can realize 81.3% ethylene faradic efficiency and 81.4% acetylene conversion rate (0.7A current) under the condition of 0.7A current. Figure 4 ) The membrane electrode catalytic energy consumption of the material is not only lower than that of the traditional flow cell electrocatalytic energy consumption, but also exceeds the membrane electrode electrocatalytic acetylene hydrogenation performance of the currently reported membrane electrode materials and mononuclear adsorbed copper coordination polymer materials. BRIEF DESCRIPTION OF DRAWINGS

[0050] Figure 1 It is a schematic diagram of a membrane electrode electrolysis cell.

[0051] Figure 2 It is a synthesis schematic diagram of a binuclear copper coordination polymer material (copper salt is selected as copper nitrate).

[0052] Figure 3 It is a synthesis schematic diagram of a binuclear copper coordination polymer material (dicarboxy-containing imidazole salt is selected as 1,3-bis(4-carboxyphenyl)-halogenated imidazole salt, and copper salt is selected as copper nitrate).

[0053] Figure 4 It is a scanning electron microscope (SEM) photo of a binuclear copper coordination polymer material.

[0054] Figure 5 It is a membrane electrode electrolysis cell (catalytic reaction area: 4cm2 Product Faraday efficiency and acetylene conversion rate distribution map at different current densities on the cathode (15 vol. % acetylene mixed gas flow rate: 60 sccm). DETAILED DESCRIPTION

[0055] The content of the present application is further described in detail below in combination with the drawings and specific examples:

[0056] The present application proposes a binuclear copper coordination polymer material for membrane electrode electrocatalytic hydrogenation and a preparation method thereof. An imidazole salt containing dicarboxylic acid is used as a ligand, and a binuclear copper coordination polymer catalytic material is synthesized by solvent thermal method and metal post-modification method in sequence. The catalytic material is uniformly dispersed in a solvent to prepare a slurry with a certain concentration, which is uniformly coated on a gas diffusion layer as a cathode electrode, a non-precious metal-based material (such as NiFeCo 0.5 -LDH / Ni, NiFeCo 0.5 -LDH / Ti, IrO x / Ti, etc.) as an anode electrode, and an ion exchange membrane as a diaphragm between the cathode and the anode, to be assembled into a membrane electrode electrolysis cell reaction device. Figure 1 It is a schematic diagram of a membrane electrode electrolysis cell.

[0057] In the synthesis step of the mononuclear copper coordination polyimidazole salt, the imidazole salt containing dicarboxylic acid includes but is not limited to 1,3-bis(4-carboxyphenyl)-halogenated imidazole salt, 1,3-bis[(4-carboxy-3',5'-diisopropyl)biphenyl]-halogenated imidazole salt, 4,7-bis(4-carboxyphenyl)-1,3-dimethylbenzimidazole halide salt, 3-[(4,4'-dicarboxy[1,1'-biphenyl]-2-yl)methyl]-1-methyl-1H-halogenated imidazole salt, and derivatives thereof; the copper salt used includes but is not limited to copper nitrate, copper halide, and cuprous halide, and the solvent (organic solvent A) used includes but is not limited to N,N-dimethylformamide, methanol, acetone, tetrahydrofuran, and 1,4-dioxane.

[0058] In the synthesis step of the binuclear copper coordination polymer material, the inert gas includes but is not limited to nitrogen and argon; the base used includes but is not limited to 1,8-diazabicyclo[5.4.0]undec-7-ene, potassium carbonate, and potassium tert-butoxide; the good solvent (organic solvent B) used includes but is not limited to tetrahydrofuran, methanol, and acetone; and the copper salt used includes but is not limited to copper halide, cuprous halide, and copper nitrate.

[0059] The binder includes but is not limited to polytetrafluoroethylene emulsion, perfluorosulfonic acid resin emulsion, and fluorocarbon resin emulsion; and the solvent (organic solvent C) used for preparing the slurry includes but is not limited to isopropyl alcohol, ethanol, methanol, and acetone, which are volatile organic solvents.

[0060] The gas diffusion layer is 5% polytetrafluoroethylene, which is placed on a flat material made of carbon fiber paper, carbon fiber woven cloth, non-woven fabric or carbon black paper.

[0061] The anode current collector includes but is not limited to nickel foam, copper mesh, titanium felt, carbon paper, carbon cloth, etc.

[0062] The catalytic reaction area of the membrane electrode electrolytic cell is mainly 1*1cm 2 , 2*2cm 2 and 5*5cm 2 .

[0063] The anode electrolyte used is an acidic, neutral, alkaline electrolyte or a solid electrolyte, including but not limited to: 0.01-5M hydrochloric acid, 0.01-5M sulfuric acid, 0.01-5M KCl solution, 0.01-10M KHCO3 solution or 0.01-10M KOH solution, etc.

[0064] The present application provides a synthesis diagram of binuclear copper coordination polymer catalytic material (Cu(Bcpi) / Cu), as shown in Figure 2 (Wherein, the square represents an aromatic ring), the specific synthesis steps are as follows:

[0065] (1) 0.4mmol of dicarboxy-containing imidazole salt and 0.4mmol of copper nitrate are added to 50mL of N,N-dimethylformamide, stirred and ultrasonic for a period of time to make it fully dispersed, then transferred to a hydrothermal reactor 120℃ solvent thermal reaction for 24h, after the reaction is completed and cooled to room temperature, the reaction product is washed with a good solvent for several times and vacuum filtration, then the filtration solid is placed in a 60℃ oven overnight drying, to obtain mononuclear copper coordination polymer imidazole salt (Cu(Bcpi)).

[0066] (2) 20mg of mononuclear copper coordination polymer imidazole salt, 3mg of potassium tert-butoxide and 10mg of copper chloride are added to 5mL of anhydrous methanol, and the reaction is carried out at room temperature for 24h under inert gas protection, after the reaction is completed, the reaction product is washed with a good solvent for several times and centrifuged, then the centrifuged solid is dried to obtain binuclear copper coordination polymer material (Cu(Bcpi) / Cu).

[0067] Taking 1,3-bis(4-carboxyphenyl)-halogenated imidazole salt as an example of dicarboxy-containing imidazole salt, the synthesis principle is shown in Figure 3 , and the SEM image of the prepared binuclear copper coordination polymer catalytic material is shown in Figure 4 .

[0068] The present application provides a preparation method of the above-mentioned cathode electrode:

[0069] Accurately take a certain mass (1-100 mg) of binuclear copper coordination polymer catalytic material, add a certain volume (5-20 mL) of solvent and a certain volume (10-500 μL) of binder solution, then ultrasonic for 30-60 s and magnetic stirring for 30-60 min to obtain a uniform catalyst slurry; accurately take a certain volume (5-10 mL) of the catalyst slurry, load it on the material with a gas diffusion layer in the form of spraying, and after drying, obtain a cathode electrode.

[0070] The application provides a preparation method of the anode electrode:

[0071] (1) electrochemical deposition method: using a current collector as a working electrode and a mixed solution containing non-noble metal ions such as nickel, iron and cobalt as an electrolyte;

[0072] using Ag / AgCl or Hg / HgO as a reference electrode, depositing non-noble metal-based particles such as Fe, Co and Ni or alloys, oxides, hydroxides and composites of the non-noble metal on the current collector by a three-electrode system at a current density of 10 mA / cm 2 for a certain time (6-60 min).

[0073] (2) impregnation and thermal decomposition method: first, washing the current collector with acetone / water, and then etching in a 6M HCl solution for 30 min. Subsequently, immersing the etched current collector in a mixed solution containing isopropyl alcohol (9 mL), 6M HCl (1 mL) and a non-noble metal precursor salt of a certain concentration. After drying by an infrared lamp, calcining the current collector at 500 DEG C for 20 min. Repeating the above impregnation and thermal decomposition steps to obtain non-noble metal-based particles such as Fe, Co and Ni or alloys, oxides and composites of the non-noble metal grown on the current collector.

[0074] The application provides a method for testing the performance of the membrane electrode electrolytic cell in electrocatalytic hydrogenation of acetylene:

[0075] (1) using a membrane electrode electrolytic cell, using a gas diffusion electrode loaded with binuclear copper coordination polymer material as a cathode, and using an ion exchange membrane and a non-noble metal-based anode (such as NiFeCo 0.5 -LDH / Ni, NiFeCo 0.5 -LDH / Ti, IrO x / Ti, etc.) to form a membrane electrode.

[0076] (2) pure acetylene or a mixed gas of acetylene and other gases (inert gas, ethylene, etc.) of a certain humidity enters from the gas channel inlet of the cathode, and the corresponding product is collected from the gas channel outlet; at the same time, a peristaltic pump is used to promote the circulation of the anode electrolyte in the anode channel.

[0077] (3) The gas flow rate of the wet gas raw material is 5-1000 sccm, and the flow rate of the anolyte is 5-200 sccm.

[0078] (4) The obtained catalytic material is evaluated for the electrocatalytic acetylene hydrogenation performance by using a direct current stabilized power supply, and the content of each gas phase product is detected by using an online gas chromatograph.

[0079] Example 1

[0080] (1) When 1,3-bis(4-carboxyphenyl)-halogenated imidazole salt is used as the dicarboxy-containing imidazole salt, the obtained binuclear copper coordination polymer catalytic material (Cu(Bcpi) / Cu) is loaded on a gas diffusion electrode as the cathode of an electrolytic cell, NiFeCo 0.5 -LDH / Ni is used as the anode of the electrolytic cell, the cathode and the anode are separated by an anion exchange membrane, the anolyte is a 1M KOH solution, and the electrolytic cell components are assembled into a membrane electrode electrolytic cell (catalytic reaction area: 1 cm 2 ).

[0081] (2) The wet acetylene raw material used for the cathode is pure acetylene. The gas flow rate of the pure acetylene is controlled by a gas mass flow meter to be 60 sccm.

[0082] (3) The flow rate of the anolyte is controlled by a peristaltic pump to be 10 rpm.

[0083] (4) The electrocatalytic hydrogenation performance of the binuclear copper coordination polymer catalytic material (Cu(Bcpi) / Cu) is evaluated at a current of 0.8 A, the content of each gas phase product at the outlet of the gas chamber is detected by using an online gas chromatograph, and the Faraday efficiency of the product is calculated.

[0084] Example 2

[0085] (1) When 1,3-bis(4-carboxyphenyl)-halogenated imidazole salt is used as the dicarboxy-containing imidazole salt, the obtained binuclear copper coordination polymer catalytic material (Cu(Bcpi) / Cu) is loaded on a gas diffusion electrode as the cathode of an electrolytic cell, NiFeCo 0.5 -LDH / Ni is used as the anode of the electrolytic cell, the cathode and the anode are separated by an anion exchange membrane, the anolyte is a 1M KOH solution, and the electrolytic cell components are assembled into a membrane electrode electrolytic cell (catalytic reaction area: 1 cm 2 ).

[0086] (2) The wet acetylene raw material used for the cathode is pure acetylene. The gas flow rate of the pure acetylene is controlled by a gas mass flow meter to be 60 sccm.

[0087] (3) The flow rate of the anolyte is controlled by a peristaltic pump to be 10 rpm.

[0088] (4) The electrocatalytic hydrogenation performance of the dinuclear copper coordination polymer catalytic material (Cu(Bcpi) / Cu) was evaluated at a current of 0.5 A; the content of each gaseous product at the outlet of the gas chamber was detected using an online gas chromatograph, and the Faraday efficiency of the product was calculated.

[0089]

Example 3

[0090] (1) When 1,3-bis[(4-carboxyl-3',5'-diisopropyl) biphenyl]-halogenated imidazole salt was used as the dicarboxy-containing imidazole salt, the obtained dinuclear copper coordination polymer catalytic material (Cu(Bcpi) / Cu) was loaded on a gas diffusion electrode as an electrolytic cell cathode, and NiFeCo 0.5 -LDH / Ti was used as an electrolytic cell anode, the cathode and the anode were separated by an anion exchange membrane, the anode electrolyte was a 1M KOH solution, and the electrolytic cell components were assembled into a membrane electrode electrolytic cell (catalytic reaction area: 1 cm 2 ).

[0091] (2) The wet acetylene raw material used for the cathode was pure acetylene. The gas flow rate of pure acetylene was controlled to be 60 sccm using a gas mass flow meter.

[0092] (3) The flow rate of the anode electrolyte was controlled to be 10 rpm using a peristaltic pump.

[0093] (4) The electrocatalytic hydrogenation performance of the dinuclear copper coordination polymer catalytic material (Cu(Bcpi) / Cu) was evaluated at a current of 0.8 A; the content of each gaseous product at the outlet of the gas chamber was detected using an online gas chromatograph, and the Faraday efficiency of the product was calculated.

[0094]

Example 4

[0095] (1) When 1,3-bis(4-carboxyphenyl)-halogenated imidazole salt was used as the dicarboxy-containing imidazole salt, the obtained dinuclear copper coordination polymer catalytic material (Cu(Bcpi) / Cu) was loaded on a gas diffusion electrode as an electrolytic cell cathode, and NiFeCo 0.5 -LDH / Ti was used as an electrolytic cell anode, the cathode and the anode were separated by an anion exchange membrane, the anode electrolyte was a 1M KOH solution, and the electrolytic cell components were assembled into a membrane electrode electrolytic cell (catalytic reaction area: 1 cm 2 ).

[0096] (2) The wet acetylene raw material used for the cathode was pure acetylene. The gas flow rate of pure acetylene was controlled to be 60 sccm using a gas mass flow meter.

[0097] (3) The flow rate of the anode electrolyte was controlled to be 10 rpm using a peristaltic pump.

[0098] (4) The electrocatalytic hydrogenation performance of the dinuclear copper coordination polymer catalytic material (Cu(Bcpi) / Cu) was evaluated at a current of 0.6 A; the content of each gaseous product at the outlet of the gas chamber was detected using an online gas chromatograph, and the Faraday efficiency of the product was calculated.

[0099] Example 5

[0100] (1) When 1,3-bis(4-carboxyphenyl)-halogenated imidazole salt was used as the dicarboxy-containing imidazole salt, the obtained dinuclear copper coordination polymer catalytic material (Cu(Bcpi) / Cu) was loaded on a gas diffusion electrode as an electrolytic cell cathode, IrO 0.5 / Ti was used as an electrolytic cell anode, the cathode and the anode were separated by an anion exchange membrane, the anode electrolyte was a 1M KOH solution, and the electrolytic cell components were assembled into a membrane electrode electrolytic cell (catalytic reaction area: 1 cm 2 ).

[0101] (2) The wet acetylene raw material used for the cathode was pure acetylene. The gas flow rate of pure acetylene was controlled to be 60 sccm using a gas mass flow meter.

[0102] (3) The flow rate of the anode electrolyte was controlled to be 10 rpm using a peristaltic pump.

[0103] (4) The electrocatalytic hydrogenation performance of the dinuclear copper coordination polymer catalytic material (Cu(Bcpi) / Cu) was evaluated at a current of 0.5 A; the content of each gaseous product at the outlet of the gas chamber was detected using an online gas chromatograph, and the Faraday efficiency of the product was calculated.

[0104] Example 6

[0105] (1) When 1,3-bis(4-carboxyphenyl)-halogenated imidazole salt was used as the dicarboxy-containing imidazole salt, the obtained dinuclear copper coordination polymer catalytic material (Cu(Bcpi) / Cu) was loaded on a gas diffusion electrode as an electrolytic cell cathode, IrO x / Ti was used as an electrolytic cell anode, the cathode and the anode were separated by an anion exchange membrane, the anode electrolyte was a 1M KOH solution, and the electrolytic cell components were assembled into a membrane electrode electrolytic cell (catalytic reaction area: 1 cm 2 ).

[0106] (2) The wet acetylene raw material used for the cathode was pure acetylene. The gas flow rate of pure acetylene was controlled to be 60 sccm using a gas mass flow meter.

[0107] (3) The flow rate of the anode electrolyte was controlled to be 10 rpm using a peristaltic pump.

[0108] (4) The electrocatalytic hydrogenation performance of the dinuclear copper coordination polymer catalytic material (Cu(Bcpi) / Cu) was evaluated at a current of 0.7 A; the content of each gaseous product at the outlet of the gas chamber was detected using an online gas chromatograph, and the Faraday efficiency of the product was calculated.

[0109] Example 7

[0110] (1) When 1,3-bis(4-carboxyphenyl)-halogenated imidazole salt was used as the dicarboxy-containing imidazole salt, the obtained dinuclear copper coordination polymer catalytic material (Cu(Bcpi) / Cu) was loaded on a gas diffusion electrode as a cathode of an electrolytic cell, IrO x / Ti was used as an anode of the electrolytic cell, the cathode and the anode were separated by an anion exchange membrane, the anode electrolyte was a 1M KOH solution, and the electrolytic cell components were assembled into a membrane electrode electrolytic cell (catalytic reaction area: 1 cm 2 ).

[0111] (2) The wet acetylene raw material used for the cathode was pure acetylene. The gas flow rate of pure acetylene was controlled to be 60 sccm using a gas mass flow meter.

[0112] (3) The flow rate of the anode electrolyte was controlled to be 10 rpm using a peristaltic pump.

[0113] (4) The electrocatalytic hydrogenation performance of the dinuclear copper coordination polymer catalytic material (Cu(Bcpi) / Cu) was evaluated at a current of 0.5 A; the content of each gaseous product at the outlet of the gas chamber was detected using an online gas chromatograph, and the Faraday efficiency of the product was calculated.

[0114] Example 8

[0115] (1) When 1,3-bis(4-carboxyphenyl)-halogenated imidazole salt was used as the dicarboxy-containing imidazole salt, the obtained dinuclear copper coordination polymer catalytic material (Cu(Bcpi) / Cu) was loaded on a gas diffusion electrode as a cathode of an electrolytic cell, NiFeCo 0.5 -LDH / Ni was used as an anode of the electrolytic cell, the cathode and the anode were separated by an anion exchange membrane, the anode electrolyte was a 1M KOH solution, and the electrolytic cell components were assembled into a membrane electrode electrolytic cell (catalytic reaction area: 4 cm 2 ).

[0116] (2) The wet acetylene raw material used for the cathode was pure acetylene. The gas flow rate of pure acetylene was controlled to be 60 sccm using a gas mass flow meter.

[0117] (3) The flow rate of the anode electrolyte was controlled to be 10 rpm using a peristaltic pump.

[0118] (4) The electrocatalytic hydrogenation performance of the dinuclear copper coordination polymer catalytic material (Cu(Bcpi) / Cu) was evaluated at 1 A current. The content of each gaseous product at the outlet of the gas chamber was detected using an online gas chromatograph, and the Faraday efficiency of the product was calculated.

[0119] Example 9

[0120] (1) When 1,3-bis(4-carboxyphenyl)-halogenated imidazole salt was used as the dicarboxy-containing imidazole salt, the obtained dinuclear copper coordination polymer catalytic material (Cu(Bcpi) / Cu) was loaded on a gas diffusion electrode as an electrolytic cell cathode, and NiFeCo 0.5 -LDH / Ni was used as an electrolytic cell anode, the cathode and the anode were separated by an anion exchange membrane, the anode electrolyte was 1 M KOH solution, and the electrolytic cell components were assembled into a membrane electrode electrolytic cell (catalytic reaction area: 4 cm 2 ).

[0121] (2) The wet acetylene raw material used for the cathode was pure acetylene. The gas flow rate of pure acetylene was controlled to be 60 sccm using a gas mass flow meter.

[0122] (3) The flow rate of the anode electrolyte was controlled to be 10 rpm using a peristaltic pump.

[0123] (4) The electrocatalytic hydrogenation performance of the dinuclear copper coordination polymer catalytic material (Cu(Bcpi) / Cu) was evaluated at 0.7 A current. The content of each gaseous product at the outlet of the gas chamber was detected using an online gas chromatograph, and the Faraday efficiency of the product was calculated.

[0124] Example 10

[0125] (1) When 1,3-bis(4-carboxyphenyl)-halogenated imidazole salt was used as the dicarboxy-containing imidazole salt, the obtained dinuclear copper coordination polymer catalytic material (Cu(Bcpi) / Cu) was loaded on a gas diffusion electrode as an electrolytic cell cathode, and NiFeCo 0.5 -LDH / Ni was used as an electrolytic cell anode, the cathode and the anode were separated by an anion exchange membrane, the anode electrolyte was 1 M KOH solution, and the electrolytic cell components were assembled into a membrane electrode electrolytic cell (catalytic reaction area: 4 cm 2 ).

[0126] (2) The wet acetylene raw material used for the cathode was 15 vol.% acetylene mixed gas. The gas flow rate of the mixed gas was controlled to be 40 sccm using a gas mass flow meter.

[0127] (3) The flow rate of the anode electrolyte was controlled to be 10 rpm using a peristaltic pump.

[0128] (4) The electrocatalytic hydrogenation performance of the binuclear copper coordination polymer catalytic material (Cu(Bcpi) / Cu) was evaluated at a current of 0.5 A. The content of each gas phase product at the gas chamber outlet was detected using online gas chromatography, and the Faraday efficiency of the product was calculated.

[0129] [Example 11]

[0130] (1) When 1,3-bis(4-carboxylic acid phenyl)-halogenated imidazolium salt is used as the imidazolium salt containing dicarboxyl group, the obtained binuclear copper coordination polymer catalytic material (Cu(Bcpi) / Cu) is loaded on the gas diffusion electrode as the cathode of the electrolytic cell, and NiFeCo 0.5 -LDH / Ni was used as the anode of the electrolytic cell. The cathode and anode were separated by an anion exchange membrane. The anolyte was 1M KOH solution. The electrolytic cell components were assembled into a membrane electrode electrolytic cell (catalytic reaction area: 4 cm 2 ).

[0131] (2) The wet acetylene raw material used for the cathode is: 15 vol.% acetylene mixed gas. The gas flow rate of the mixed gas is controlled by a gas mass flow meter to be 40 sccm.

[0132] (3) The flow rate of the anolyte was controlled at 10 rpm using a peristaltic pump.

[0133] (4) The electrocatalytic hydrogenation performance of the binuclear copper coordination polymer catalytic material (Cu(Bcpi) / Cu) was evaluated at a current of 0.3 A. The content of each gas phase product at the gas chamber outlet was detected using online gas chromatography, and the Faraday efficiency of the product was calculated.

[0134] [Example 12]

[0135] (1) When 1,3-bis(4-carboxylic acid phenyl)-halogenated imidazolium salt is used as the imidazolium salt containing dicarboxyl group, the obtained binuclear copper coordination polymer catalytic material (Cu(Bcpi) / Cu) is loaded on the gas diffusion electrode as the cathode of the electrolytic cell, and NiFeCo 0.5 -LDH / Ni was used as the anode of the electrolytic cell. The cathode and anode were separated by an anion exchange membrane. The anolyte was 1M KOH solution. The electrolytic cell components were assembled into a membrane electrode electrolytic cell (catalytic reaction area: 4 cm 2 ).

[0136] (2) The wet acetylene raw material used for the cathode is: 15 vol.% acetylene mixed gas. The gas flow rate of the mixed gas is controlled by a gas mass flow meter to be 60 sccm.

[0137] (3) The flow rate of the anolyte was controlled at 10 rpm using a peristaltic pump.

[0138] (4) The electrocatalytic hydrogenation performance of the dinuclear copper coordination polymer catalytic material (Cu(Bcpi) / Cu) was evaluated at a current of 0.7 A; the content of each gaseous product at the outlet of the gas chamber was detected using an online gas chromatograph, and the Faraday efficiency of the product was calculated.

[0139] Example 13

[0140] (1) When 1,3-bis(4-carboxyphenyl)-halogenated imidazole salt was used as the dicarboxy-containing imidazole salt, the obtained dinuclear copper coordination polymer catalytic material (Cu(Bcpi) / Cu) was loaded on a gas diffusion electrode as an electrolytic cell cathode, NiFeCo 0.5 -LDH / Ni was used as an electrolytic cell anode, the cathode and the anode were separated by an anion exchange membrane, the anode electrolyte was a 1M KOH solution, and the electrolytic cell components were assembled into a membrane electrode electrolytic cell (catalytic reaction area: 4 cm 2 ).

[0141] (2) The wet acetylene raw material used for the actual cathode was 15 vol.% acetylene mixed gas. The gas flow rate of the mixed gas was controlled to be 60 sccm using a gas mass flow meter.

[0142] (3) The flow rate of the anode electrolyte was controlled to be 10 rpm using a peristaltic pump.

[0143] (4) The electrocatalytic hydrogenation performance of the dinuclear copper coordination polymer catalytic material (Cu(Bcpi) / Cu) was evaluated at a current of 0.5 A; the content of each gaseous product at the outlet of the gas chamber was detected using an online gas chromatograph, and the Faraday efficiency of the product was calculated.

[0144] Example 14

[0145] (1) When 1,3-bis(4-carboxyphenyl)-halogenated imidazole salt was used as the dicarboxy-containing imidazole salt, the obtained dinuclear copper coordination polymer catalytic material (Cu(Bcpi) / Cu) was loaded on a gas diffusion electrode as an electrolytic cell cathode, NiFeCo 0.5 -LDH / Ni was used as an electrolytic cell anode, the cathode and the anode were separated by an anion exchange membrane, the anode electrolyte was a 1M KOH solution, and the electrolytic cell components were assembled into a membrane electrode electrolytic cell (catalytic reaction area: 4 cm 2 ).

[0146] (2) The wet acetylene raw material used for the actual cathode was 15 vol.% acetylene mixed gas. The gas flow rate of the mixed gas was controlled to be 60 sccm using a gas mass flow meter.

[0147] (3) The flow rate of the anode electrolyte was controlled to be 10 rpm using a peristaltic pump.

[0148] (4) The electrocatalytic hydrogenation performance of the dinuclear copper coordination polymer catalytic material Cu(Bcpi) / Cu was evaluated at a current of 0.7 A; the content of each gaseous product at the outlet of the gas chamber was detected using an online gas chromatograph, and the Faraday efficiency of the product was calculated.

[0149] Example 15

[0150] (1) When 1,3-bis(4-carboxyphenyl)-halogenated imidazole salt is used as a dicarboxy-containing imidazole salt, the obtained dinuclear copper coordination polymer catalytic material (Cu(Bcpi) / Cu) is loaded on a gas diffusion electrode as a cathode of an electrolytic cell, NiFeCo 0.5 -LDH / Ni is used as an anode of the electrolytic cell, the cathode and the anode are separated by an anion exchange membrane, and the anode electrolyte is a 1M KOH solution. The electrolytic cell components are assembled into a membrane electrode electrolytic cell (catalytic reaction area: 4 cm 2 ).

[0151] (2) The wet acetylene raw material used for the cathode is 15 vol.% acetylene mixed gas. The gas flow rate of the mixed gas is controlled to be 100 sccm using a gas mass flow meter.

[0152] (3) The flow rate of the anode electrolyte is controlled to be 10 rpm using a peristaltic pump.

[0153] (4) The electrocatalytic hydrogenation performance of the dinuclear copper coordination polymer catalytic material Cu(Bcpi) / Cu was evaluated at a current of 0.4 A; the content of each gaseous product at the outlet of the gas chamber was detected using an online gas chromatograph, and the Faraday efficiency of the product was calculated.

[0154] Comparative Example

[0155] (1) 20 mg of a mononuclear copper coordination polyimidazole salt and 10 mg of a copper salt are added to 5 mL of anhydrous solvent, and the reaction is carried out at room temperature for 24 h under inert gas protection. After the reaction is completed, the reaction product is washed and centrifuged multiple times using a good solvent, and then the centrifuged solid is dried to obtain a mononuclear copper coordination polymer (Cu(Bcpi)-ACu) adsorbed with copper as a comparative material.

[0156] (2) The gas diffusion electrode loaded with the above Cu(Bcpi)-ACu is used as a cathode of an electrolytic cell, and NiFeCo 0.5 -LDH / Ni is used as an anode of the electrolytic cell, the cathode and the anode are separated by an anion exchange membrane, and the anode electrolyte is a 1M KOH solution. The electrolytic cell components are assembled into a membrane electrode electrolytic cell (catalytic reaction area: 1 cm 2 ).

[0157] (3) The wet acetylene raw material used for the cathode is pure acetylene. The gas flow rate of pure acetylene is controlled by a gas mass flow meter to be 60 sccm.

[0158] (4) The flow rate of the anolyte was controlled at 10 rpm using a peristaltic pump.

[0159] (5) The electrocatalytic hydrogenation performance of the copper coordination polymer catalytic material (Cu(Bcpi)-ACu) was evaluated using a DC regulated power supply. The content of each gas phase product at the gas chamber outlet was detected using an online gas chromatograph, and the Faraday efficiency of the product was calculated.

[0160] The specific evaluation results are shown in Table 1.

[0161] Table 1

[0162]

[0163]

[0164] As shown in Table 1: The membrane electrode PdCu / C material (ACS Appl. Mater. Interfaces, 2024, 16, 8668-8678) can obtain an ethylene Faraday efficiency of <75% at a current of 0.2A. Under the same acetylene atmosphere, the binuclear copper coordination polymer material (Cu(Bcpi) / Cu) obtained by the present invention exhibits a better ethylene Faraday efficiency at a higher current (0.6A~1A), while optimizing the membrane electrode performance while reducing the amount of precious metal Pd. It is worth mentioning that Cu(Bcpi) / Cu can achieve an ethylene Faraday efficiency of 88.2% at a current of 0.8A, which is not only better than the performance of the existing reported materials, but also significantly better than the ethylene Faraday efficiency (47.6%) of the mononuclear adsorbed copper coordination polymer material (Cu(Bcpi)-ACu) at the same current.

[0165] In addition, the present invention also prepares other binuclear copper coordination polymer materials according to the same method within the aforementioned process range, and applies them as hydrogenation materials in membrane electrode electrocatalytic hydrogenation to produce ethylene. They all have excellent electrocatalytic acetylene hydrogenation performance and can effectively suppress hydrogen evolution by-products, meeting the needs.

[0166] The above description is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with this technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed in the present invention, and these modifications or replacements should all be included in the scope of protection of the present invention.

Claims

1. Application of binuclear copper coordination polymer materials as hydrogenation materials in membrane electrode electrocatalytic hydrogenation to ethylene; The molecular structure of the binuclear copper coordination polymer material is: in, The boxes represent aromatic rings; Its synthesis method comprises the following steps: 1) Weighing a dicarboxyl-containing imidazole salt and a copper salt, adding an organic solvent A thereto, stirring and ultrasonically dispersing them sufficiently to obtain a mixed solution; The mixed solution is transferred to a reactor for a solvothermal reaction. After the reaction is completed and cooled to room temperature, the reaction product is rinsed multiple times and filtered under reduced pressure. The filtered solid is then dried to obtain a mononuclear copper coordinated polyimidazole salt. The dicarboxyl-containing imidazole salt is any one of 1,3-bis(4-carboxylic acid phenyl)-halogenated imidazole salt, 1,3-bis[(4-carboxyl-3',5'-diisopropyl)biphenyl]-halogenated imidazole salt, 4,7-bis(4-carboxylphenyl)-1,3-dimethylbenzimidazole halide salt or 3-[(4,4'-dicarboxyl[1,1'-biphenyl]-2-yl)methyl]-1-methyl-1H-halogenated imidazole salt and derivatives thereof; 2) dispersing the mononuclear copper coordinated polyimidazole salt and copper salt obtained in step 1) in an organic solvent B, stirring and reacting under inert gas and alkaline conditions, eluting and centrifuging the reaction product multiple times after the reaction, and then drying the solid after centrifugation to obtain a binuclear copper coordination polymer material; The base used in the alkaline condition is 1,8-diazabicyclo[5.4.0]undec-7-ene, potassium carbonate or potassium tert-butoxide.

2. The application according to claim 1, characterized in that: In step 1), the copper salt is copper nitrate, copper halide or cuprous halide; The organic solvent A is N,N-dimethylformamide, methanol, acetone, tetrahydrofuran or 1,4-dioxane; The molar ratio of the dicarboxyl-containing imidazole salt to the copper salt is 1:1 to 1:1.5; The ratio of the raw material to the organic solvent A is 1:125-250, mmol / mL; the amount of the raw material here refers to the total amount of the dicarboxyl-containing imidazole salt and the copper salt; The temperature of the solvent thermal reaction is 120-160° C., and the reaction time is 24-48 hours.

3. The use according to claim 1 or 2, characterized in that: In step 2), the copper salt is copper nitrate, copper halide or cuprous halide; The organic solvent B is tetrahydrofuran, methanol or acetone; The molar ratio of the mononuclear copper coordinated polyimidazole salt to the copper salt is 1:1 to 1:1.5; The ratio of the raw material to the organic solvent B is 1:100-400, mmol / mL; the amount of the raw material here refers to the total amount of the mononuclear copper coordinated polyimidazole salt and the copper salt; The reaction temperature is 20-60° C., and the reaction time is 24-48 hours.

4. A method for preparing ethylene by membrane electrode electrocatalytic hydrogenation, characterized in that: The following steps are involved: S1. Weigh the binuclear copper coordination polymer material according to any one of claims 1-3 as a cathode electrocatalytic hydrogenation material, add a binder, and evenly disperse it in a volatile organic solvent C to obtain a cathode material slurry; S2. The cathode material slurry obtained in S1 is evenly coated on the gas diffusion layer and fully dried as a cathode standby; S3. Assemble the non-precious metal-based anode, the cathode obtained in S2, and the ion exchange membrane into a membrane electrode electrolysis cell, and perform an electrocatalytic acetylene hydrogenation reaction to produce ethylene.

5. The method for preparing ethylene by membrane electrode electrocatalytic hydrogenation according to claim 4, characterized in that: In S1, the adhesive is polytetrafluoroethylene emulsion, perfluorosulfonic acid resin emulsion or fluorocarbon resin emulsion; The organic solvent C is isopropanol, ethanol, methanol or acetone; The material ratio of the binuclear copper coordination polymer material, the organic solvent C and the adhesive is 1-100:5-20:10-500, mg:mL:μL.

6. The method for preparing ethylene by membrane electrode electrocatalytic hydrogenation according to claim 4 or 5, characterized in that: In S2, the cathode material slurry is evenly coated on the gas diffusion layer by spraying; The gas diffusion layer is 5% polytetrafluoroethylene and is placed on a flat plate material. The material of the flat plate material is carbon fiber paper, carbon fiber woven cloth, non-woven fabric or carbon black paper.

7. The method for preparing ethylene by membrane electrode electrocatalytic hydrogenation according to claim 6, characterized in that: In S3, the non-noble metal-based anode is prepared by growing non-noble metal-based particles or their alloys, oxides, hydroxides, or composites on the anode current collector by impregnation or electrodeposition; The anode current collector is nickel foam, copper mesh, titanium felt, carbon paper or carbon cloth; The acetylene is a wet acetylene raw material, and the wet acetylene raw material used is pure acetylene or a mixture of acetylene and other gases; the flow rate of the wet acetylene raw material used is 5 to 1000 sccm.

8. The method for preparing ethylene by membrane electrode electrocatalytic hydrogenation according to claim 7, characterized in that: In S3, wet acetylene raw material enters from the gas channel inlet of the cathode, and the corresponding product is collected from the gas channel outlet; at the same time, a peristaltic pump is used to promote the circulation of the anode electrolyte in the anode channel.

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