Sn-Cu3Sn1 / Cu catalyst and its preparation, supported copper-tin catalyst electrode and its preparation and application

Abstract

This invention discloses a Sn-Cu3Sn1 / Cu catalyst and its preparation, as well as a supported copper-tin catalyst electrode and its preparation and application. The microstructure of the Sn-Cu3Sn1 / Cu catalyst consists of a Cu3Sn1 alloy layer reconstructed on the surface of copper nanoparticles, with Sn atoms grown at the Sn sites of the Cu3Sn1 alloy as termination sites. The supported copper-tin catalyst electrode is obtained by uniformly mixing a slurry containing the Sn-Cu3Sn1 / Cu catalyst with a 5%-25% (w / w) Nafion solution, uniformly coating the mixed slurry onto an electrode material, and then drying. This invention provides the application of the supported copper-tin catalyst electrode in the electrocatalytic selective hydrogenation of acetylene, exhibiting advantages such as high conversion rate, high selectivity, and high Faradaic efficiency.

Description

Technical Field

[0001] This invention belongs to the field of electrocatalytic selective hydrogenation technology of acetylene, specifically relating to a Sn-Cu3Sn1 / Cu catalyst and its preparation method, a supported copper-tin catalyst electrode and its preparation method, and its application in the electrocatalytic selective hydrogenation reaction of acetylene. Background Technology

[0002] Ethylene is an important component in chemical synthesis. However, the crude ethylene gas produced industrially contains 0.1-2.0% acetylene by volume. The strong coordination of acetylene can poison and deactivate the (Ziegler-Natta) catalyst used in ethylene polymerization. Therefore, it is necessary to remove acetylene from the ethylene feedstock.

[0003] Thermocatalytic acetylene hydrogenation typically requires temperatures above 200°C, pressures of approximately 5 atmospheres, and the use of expensive hydrogen gas. Furthermore, thermocatalytic selective acetylene hydrogenation often uses palladium as a catalyst, which presents problems such as the tendency for acetylene to be over-hydrogenated to ethane and low selectivity for ethylene.

[0004] Compared to traditional thermocatalytic acetylene hydrogenation, electrocatalytic selective acetylene hydrogenation offers advantages such as high selectivity, mild reaction conditions, and low cost. Furthermore, the added hydrogen atoms originate from the dissociation of water molecules in the electrolyte solution, eliminating the costs and safety hazards associated with hydrogen production, transportation, and storage. Copper-based catalysts are commonly used in electrocatalytic acetylene hydrogenation due to their high catalytic performance and low cost, indicating the technology's significant potential. However, copper-based catalysts also exhibit good catalytic performance in hydrogen evolution. Moreover, acetylene intermediates activated on the surface of copper-based catalysts may undergo C-C coupling reactions, producing butadiene, isobutene, and other (C4) byproducts. The presence of these side reactions leads to low Faraday efficiency in copper-based catalysts.

[0005] Based on the above-mentioned prior art, the inventors aim to invent a catalyst that exhibits high catalytic activity in the electrocatalytic hydrogenation reaction of acetylene and can effectively suppress the production of hydrogen and C4, thereby improving the selectivity and Faraday efficiency of ethylene. Summary of the Invention

[0006] To improve the selective hydrogenation of acetylene to ethylene via electrocatalysis and effectively suppress the production of hydrogen and C4, this invention provides a Sn-Cu3Sn1 / Cu catalyst with high conversion rate, high selectivity and high Faradaic efficiency, its preparation method, a supported copper-tin catalyst electrode and its preparation method, and its application in the electrocatalytic hydrogenation reaction of acetylene.

[0007] The present invention specifically adopts the following technical solution:

[0008] In a first aspect, the present invention provides a Sn-Cu3Sn1 / Cu catalyst, the microstructure of which is formed by reconstructing a Cu3Sn1 alloy layer (copper atoms and tin atoms arranged regularly) on the surface of copper nanoparticles, and Sn atoms are grown at the Sn sites of the Cu3Sn1 alloy as termination sites.

[0009] In a second aspect, the present invention provides a method for preparing the Sn-Cu3Sn1 / Cu catalyst described in the first aspect, comprising the following steps:

[0010] Step 1: Dissolve copper salt and tin salt in water and stir until homogeneous to prepare solution A, wherein the Sn / Cu molar ratio is 0.01-0.2, preferably 0.04-0.06;

[0011] Step 2: Prepare concentrations between 0.1-10 mol / L -1 Aqueous solution of sodium borohydride B;

[0012] Step 3: Quickly add sodium borohydride aqueous solution B to solution A at -10℃~25℃ and let it stand for 2-6 hours;

[0013] Step 4: Collect the solid in the solution, wash and dry to obtain the Sn-Cu3Sn1 / Cu catalyst.

[0014] Preferably, the copper salt mentioned in step one is selected from at least one of copper chloride, copper nitrate, copper sulfate, copper phosphate, copper pyrophosphate, basic copper carbonate, and copper acetate.

[0015] Preferably, the tin salt mentioned in step one is selected from at least one of stannous chloride, stannous tetrachloride, stannous nitrate, and stannous sulfate.

[0016] In step three of this invention, the feeding ratio of the sodium borohydride aqueous solution B to solution A is preferably such that the sodium borohydride in solution B can completely reduce the metal ions in solution A to zero-valent metals, and preferably, sodium borohydride is in excess.

[0017] Preferably, in step three, the temperature is controlled between -10°C and 5°C, and more preferably at 0°C.

[0018] Preferably, the drying in step four is performed in a vacuum oven at 40℃-120℃ for 6-12 hours.

[0019] Preferably, in step four, the washing reagents are water and ethanol.

[0020] Thirdly, the present invention provides a copper-tin catalyst supported electrode, which is obtained by uniformly mixing a slurry containing the Sn-Cu3Sn1 / Cu catalyst described in the first aspect with a Nafion solution of 5%-25% by mass, uniformly coating the mixed slurry onto an electrode material, and then drying it.

[0021] Preferably, the concentration of the slurry containing the Sn-Cu3Sn1 / Cu catalyst is 0.5-10 mg / ml. -1 The volume ratio of the slurry containing the Sn-Cu3Sn1 / Cu catalyst to the Nafion solution is 2500:30-200. More preferably, the concentration of the slurry containing the Sn-Cu3Sn1 / Cu catalyst is 10 mg / ml. -1 The mass fraction of the Nafion solution is 5%, and the volume ratio of the slurry containing the Sn-Cu3Sn1 / Cu catalyst to the volume of the Nafion solution is 2500:150.

[0022] Preferably, the electrode material is at least one of carbon paper, carbon cloth, nickel foam, and copper foam.

[0023] As a further preferred embodiment, the electrode material is carbon paper, and the loading of the mixed slurry on the carbon paper is 0.1-2 mg / cm³. 2 More preferably, it is 0.8–1.2 mg / cm³. 2 .

[0024] Fourthly, the present invention provides a method for preparing the copper-tin catalyst electrode described in the third aspect, comprising the following steps:

[0025] Step A: Add Sn-Cu3Sn1 / Cu catalyst to the solvent to prepare a solution of 0.5-10 mg / ml. -1 The ink-like slurry is then mixed with 5%-25% Nafion solution by mass, and the mixture is ultrasonically treated to ensure thorough dispersion.

[0026] Step B: Wash the cut electrode material (preferably with hydrochloric acid, ethanol and deionized water) and then dry it;

[0027] Step C: The mixed slurry obtained in step A is evenly coated onto the electrode material obtained in step B, and then irradiated with an infrared lamp until the slurry is completely dry to obtain a copper-tin catalyst-supported electrode.

[0028] Preferably, the solvent mentioned in step A is selected from at least one of deionized water, acetone, ethanol, isobutanol, ethylene glycol, n-propanol, and isopropanol.

[0029] Preferably, the ultrasonic waves used in step A have a frequency of 20-100 kHz and an ultrasonic duration of 0.5-3 hours.

[0030] Preferably, in step A, the volume ratio of the slurry containing the Sn-Cu3Sn1 / Cu catalyst to the Nafion solution is 2500:30 to 200. More preferably, the concentration of the slurry containing the Sn-Cu3Sn1 / Cu catalyst is 10 mg / ml. -1 The mass fraction of the Nafion solution is 5%, and the volume ratio of the slurry containing the Sn-Cu3Sn1 / Cu catalyst to the volume of the Nafion solution is 2500:150.

[0031] Preferably, the electrode material in step B is at least one of carbon paper, carbon cloth, nickel foam, and copper foam.

[0032] As a further preferred embodiment, the electrode material is carbon paper, and the loading of the mixed slurry on the carbon paper is 0.1-2 mg / cm³. 2 More preferably, it is 0.8–1.2 mg / cm³. 2 .

[0033] Preferably, the infrared lamp in step C has a power of 100-300W and an irradiation time of 10-60min.

[0034] Fifthly, the present invention provides an application of the copper-tin catalyst electrode described in the third aspect in the electrocatalytic selective hydrogenation reaction of acetylene.

[0035] Preferably, the application is performed according to the following steps:

[0036] Step 1: Place the copper-tin catalyst-supported electrode at the cathode of the electrochemical device as the working electrode, and select nickel foam or copper foam as the counter electrode, with an ion exchange membrane and 0.5-2 mol L⁻¹ in between. -1 The KOH electrolyte solution separates the two electrodes;

[0037] Step 2: Introduce the acetylene-containing feed gas into the acetylene chamber of the electrocatalytic acetylene hydrogenation reaction system through the inlet;

[0038] Step 3: Turn on the power supply to bring the working electrode to the reaction potential. Acetylene gas diffuses to the working electrode to carry out the electrocatalytic hydrogenation reaction of acetylene, so that acetylene is selectively hydrogenated to ethylene.

[0039] Step 4: The acetylene hydrogenation gas product is discharged from the outlet of the acetylene chamber.

[0040] Preferably, the electrochemical device in step 1 can be an H-type electrolytic cell or a flow electrolytic cell.

[0041] Preferably, the ion exchange membrane in step 1 is at least one of commercially available ion exchange membranes, such as a proton exchange membrane or anion exchange membrane.

[0042] Preferably, the acetylene-containing feed gas in step 2 can be ethylene-rich gas with an acetylene concentration between 0.5% and 10%, or it can be pure acetylene gas.

[0043] Preferably, the flow rate of the acetylene-containing feed gas in step 2 is 1 ml / min. -1 -60ml min -1 .

[0044] Preferably, the power source in step 3 is at least one of an electrochemical workstation, a constant current power source, and a constant voltage power source.

[0045] Preferably, in step 3, the reaction potential is 0V to -1.5V relative to the reversible hydrogen electrode.

[0046] Compared with the prior art, the present invention has the following innovations and advantages:

[0047] (1) The Sn-Cu3Sn1 / Cu catalyst of the present invention uses Sn termination sites as active centers. Compared with the surface of Cu nanoparticles, which are prone to carbon-carbon coupling reaction and hydrogen evolution reaction, Sn termination sites effectively avoid the formation of C4 byproducts and hydrogen.

[0048] (2) Using Sn-Cu3Sn1 / Cu catalyst, acetylene can be converted into ethylene under expanded reactor and high flow rate feed gas conditions, which can create conditions for the large-scale application of electrocatalytic acetylene hydrogenation reaction.

[0049] (3) Compared with traditional thermocatalytic technology, the electrocatalytic selective hydrogenation reaction method of acetylene described in this invention can reduce acetylene gas to ethylene at room temperature and pressure without consuming hydrogen. This can significantly improve the selectivity of the reaction and greatly reduce the energy consumption of the process, which is more in line with the requirements of green chemical industry and is of great strategic significance. Attached Figure Description

[0050] Figure 1 It is at -0.4V (V vs. RHE) and 50ml min -1 Graphs showing the conversion of EASR reactants and the FE (%) of products at different flow rates using different catalysts;

[0051] Figure 2 The images show the XRD patterns of the Cu, Sn-Cu3Sn1 / Cu, Sn / Cu, Cu6Sn4 and Cu6Sn5 catalysts prepared in the examples and comparative examples.

[0052] Figure 3 These are HAADF-STEM images of the Sn-Cu3Sn1 / Cu catalyst prepared in Example 1;

[0053] Figure 4 This is a schematic diagram of the one-step synthesis of Sn-Cu3Sn1 / Cu catalyst and EASR. Detailed Implementation

[0054] The present invention will now be illustrated with specific embodiments. It should be noted that these embodiments are merely for further illustrative purposes and should not be construed as limiting the scope of protection of the invention. The invention is not limited thereto in any way. Those skilled in the art can make some non-essential improvements and adjustments based on the above description.

[0055] Example 1: Synthesis of Sn-Cu3Sn1 / Cu catalyst and its application in the electrocatalytic hydrogenation of acetylene.

[0056] Solution A was prepared by dissolving 862 mg of anhydrous copper chloride and 64 mg of stannous chloride in 10 ml of deionized water. This yielded 10 ml of a solution with a concentration of 5 mol / L. -1 A sodium borohydride aqueous solution B was prepared by rapidly adding 10 ml of solution B to 10 ml of solution A at 0 °C and allowing it to stand for 2 hours. The black solid in the solution was collected and then washed several times with water and ethanol. The solid was then dried in a vacuum oven at 40 °C for 12 hours. The resulting catalyst was named Sn-Cu3Sn1 / Cu. The XRD pattern and HAADF-STEM image of this Sn-Cu3Sn1 / Cu catalyst are shown below. Figure 2 and Figure 3 ; Figure 2 XRD patterns show that the Sn-Cu3Sn1 / Cu catalyst mainly consists of a Cu phase, with small amounts of Cu3Sn1 and Sn phases. This can be confirmed by standard cards for Cu, Cu3Sn1, and Sn (JCPDS PDF#04-0836, JCPDS PDF#01-074-6752, and JCPDS PDF / 04-0673). The XRD pattern results are consistent with... Figure 3 The structure of the Cu3Sn1 alloy, as detected by HAAD-STEM, shows that Sn atoms grow at the Sn sites as termination sites, consistent with the desired structure. This demonstrates the successful synthesis of the Sn-Cu3Sn1 / Cu catalyst.

[0057] Take 25 mg of Sn-Cu3Sn1 / Cu catalyst and add it to 2500 μL of anhydrous ethanol solvent to prepare a 10 mg / mL solution. -1 The ink-like slurry was then mixed with 150 μL of 5% Nafion solution. The slurry was ultrasonically treated at 60 kHz for 0.5 hours. The carbon paper was then cut into 25 cm pieces. 2 The mixture was then washed with ethanol and deionized water and dried. The prepared slurry was then evenly coated onto carbon paper with a loading of 1 mg / cm². 2The slurry was completely dried by irradiating it with a 100W infrared lamp for 50 minutes, resulting in a carbon paper-supported Sn-Cu3Sn1 / Cu electrode.

[0058] The prepared carbon paper-supported Sn-Cu3Sn1 / Cu electrode was placed as the cathode of a flowing electrolytic cell as the working electrode, and nickel foam was selected as the counter electrode. A proton exchange membrane and 1 mol L⁻¹ were used as interlayers. -1 The KOH electrolyte solution separates the two electrodes. The flow rate is 50 ml / min. -1 An ethylene-rich feed gas containing 0.5% acetylene (20% ethylene, 0.5% acetylene, and the remainder argon) is introduced into the acetylene chamber of the electrocatalytic acetylene hydrogenation reaction system through the inlet. The electrochemical workstation is connected, and the working electrode potentials are set to -0.2V, -0.4V, and -0.6V, respectively. The acetylene gas diffuses to the working electrodes to undergo the electrocatalytic acetylene hydrogenation reaction, selectively hydrogenating acetylene to ethylene. Gas chromatography is used to analyze the acetylene hydrogenation gas products discharged from the acetylene chamber outlet.

[0059] At a reaction potential of -0.2 V, the Sn-Cu3Sn1 / Cu catalyst exhibited a conversion of 93.5%, a selectivity of 90.4%, and a Faradaic efficiency of 89.2%. At a reaction potential of -0.4 V, the Sn-Cu3Sn1 / Cu catalyst achieved a conversion of 100.0%, a selectivity of 92.9%, and a Faradaic efficiency of 86.2%. At a reaction potential of -0.6 V, the Sn-Cu3Sn1 / Cu catalyst achieved a conversion of 100.0%, a selectivity of 95.3%, and a Faradaic efficiency of 79.1%. (The last sentence appears to be incomplete and possibly refers to a different reaction timeframe.) -1 Data on the conversion of EASR reactants and the FE (%) of products at the given flow rate using this catalyst are shown in [reference needed]. Figure 1 .

[0060] Comparative Example 1: Synthesis of Sn / Cu catalyst and its application in the electrocatalytic hydrogenation of acetylene.

[0061] Solution A was prepared by dissolving 1.07 g of anhydrous copper chloride and 0.38 g of stannous chloride in 10 ml of deionized water, and then preparing 10 ml of solution A with a concentration of 5 mol / L. -1 A sodium borohydride aqueous solution B was prepared by rapidly adding 10 ml of solution B to 10 ml of solution A at 0 °C and allowing it to stand for 2 hours. The black solid in the solution was collected and then washed several times with water and ethanol. The solid was then dried in a vacuum oven at 40 °C for 12 hours. The resulting catalyst was named Sn / Cu, and its XRD pattern is shown below. Figure 2 . Figure 2 The results show that as the molar ratio of metal Sn increases, the peak representing metal Sn in the Sn / Cu catalyst increases.

[0062] Take 25 mg of Sn / Cu catalyst and add it to 2500 μL of anhydrous ethanol solvent to prepare a 10 mg / mL solution. -1 The ink-like slurry was then mixed with 150 μL of 5% Nafion solution. The slurry was ultrasonically treated at 60 kHz for 0.5 hours. The carbon paper was then cut into 25 cm pieces. 2 The mixture was then washed with ethanol and deionized water and dried. The prepared slurry was then evenly coated onto carbon paper with a loading of 1 mg / cm². 2 The slurry was completely dried by irradiating it with a 100W infrared lamp for 50 minutes, resulting in a carbon paper-supported Sn / Cu electrode.

[0063] The prepared carbon paper-supported Sn / Cu electrode was placed as the cathode of a flowing electrolytic cell as the working electrode, and nickel foam was selected as the counter electrode. A proton exchange membrane and 1 mol L⁻¹ were used in between. -1 The KOH electrolyte solution separates the two electrodes. The flow rate is 50 ml / min. -1 An ethylene-rich feed gas containing 0.5% acetylene (20% ethylene, 0.5% acetylene, and the remainder argon) is introduced into the acetylene chamber of the electrocatalytic acetylene hydrogenation reaction system through the inlet. The electrochemical workstation is connected, and the working electrode potentials are set to -0.2V, -0.4V, and -0.6V, respectively. The acetylene gas diffuses to the working electrodes to undergo the electrocatalytic acetylene hydrogenation reaction, selectively hydrogenating acetylene to ethylene. Gas chromatography is used to analyze the acetylene hydrogenation gas products discharged from the acetylene chamber outlet.

[0064] At a reaction potential of -0.2 V, the Sn / Cu catalyst achieved a conversion of 79.7%, a selectivity of 80.9%, and a Faradaic efficiency of 62.5%. At a reaction potential of -0.4 V, the Sn / Cu catalyst achieved a conversion of 90.1%, a selectivity of 88.7%, and a Faradaic efficiency of 87.3%. At a reaction potential of -0.6 V, the Sn / Cu catalyst achieved a conversion of 99.4%, a selectivity of 89.2%, and a Faradaic efficiency of 65.6%. (The last sentence appears to be incomplete and possibly refers to a different reaction timeframe.) -1 Data on the conversion of EASR reactants and the FE (%) of products at the given flow rate using this catalyst are shown in [reference needed]. Figure 1 .

[0065] Comparative Example 2: Synthesis of Cu6Sn4 catalyst and its application in the electrocatalytic hydrogenation of acetylene.

[0066] Solution A was prepared by dissolving 202 mg anhydrous copper chloride, 189 mg stannous chloride, and 774 mg sodium citrate in 20 ml of water. Solution A was stirred on a magnetic stirrer for 10 min at room temperature. The prepared concentration was approximately 0.2 mol / L. -1A sodium borohydride aqueous solution B was prepared. 40 ml of solution B was rapidly added to 20 ml of solution A, and the mixture was heated at 80 °C for 5 hours. The black solid in the solution was collected and then washed several times with water and ethanol. The solid was then dried in a vacuum oven at 100 °C for 12 hours. The resulting catalyst was named Cu6Sn4, and its XRD pattern is shown below. Figure 2 .

[0067] Take 25 mg of Cu6Sn4 catalyst and add it to 2500 μL of anhydrous ethanol solvent to prepare a 10 mg L solution. -1 The ink-like slurry was then mixed with 150 μL of 5% Nafion solution. The slurry was ultrasonically treated at 60 kHz for 0.5 hours. The carbon paper was then cut into 25 cm pieces. 2 The mixture was then washed with ethanol and deionized water and dried. The prepared slurry was then evenly coated onto carbon paper with a loading of 1 mg / cm². 2 The slurry was completely dried by irradiating it with a 100W infrared lamp for 50 minutes, resulting in a carbon paper-supported Cu6Sn4 electrode.

[0068] The prepared carbon paper-supported Cu6Sn4 electrode was placed as the cathode of a flowing electrolytic cell as the working electrode, and nickel foam was selected as the counter electrode. A proton exchange membrane and 1 mol L⁻¹ were used in between. -1 The KOH electrolyte solution separates the two electrodes. The flow rate is 50 ml / min. -1 An ethylene-rich feed gas containing 0.5% acetylene (20% ethylene, 0.5% acetylene, and the remainder argon) is introduced into the acetylene chamber of the electrocatalytic acetylene hydrogenation reaction system through the inlet. The electrochemical workstation is connected, and the working electrode potentials are set to -0.2V, -0.4V, and -0.6V, respectively. The acetylene gas diffuses to the working electrodes to undergo the electrocatalytic acetylene hydrogenation reaction, selectively hydrogenating acetylene to ethylene. Gas chromatography is used to analyze the acetylene hydrogenation gas products discharged from the acetylene chamber outlet.

[0069] At a reaction potential of -0.2 V, the conversion of the catalyst Cu6Sn4 was 20.1%, the selectivity was 71.3%, and the Faradaic efficiency was 60.4%. At a reaction potential of -0.4 V, the conversion of the catalyst Cu6Sn4 was 38.5%, the selectivity was 81.3%, and the Faradaic efficiency was 75.5%. At a reaction potential of -0.6 V, the conversion of the catalyst Cu6Sn4 was 44.6%, the selectivity was 87.1%, and the Faradaic efficiency was 50.9%. (The last sentence appears to be incomplete and possibly refers to a different reaction timeframe.) -1 Data on the conversion of EASR reactants and the FE (%) of products at the given flow rate using this catalyst are shown in [reference needed]. Figure 1 .

[0070] Comparative Example 3: Synthesis of Cu6Sn5 catalyst and its application in the electrocatalytic hydrogenation of acetylene.

[0071] Solution A was prepared by dissolving 161 mg anhydrous copper chloride, 189 mg stannous chloride, and 774 mg sodium citrate in 20 mL of water. Solution A was stirred on a magnetic stirrer for 10 min at room temperature. The prepared concentration was approximately 0.2 mol / L. -1 A sodium borohydride aqueous solution B was prepared. 40 ml of solution B was rapidly added to 20 ml of solution A, and the mixture was heated at 80 °C for 5 hours. The black solid in the solution was collected and then washed several times with water and ethanol. The solid was dried in a vacuum oven at 100 °C for 12 hours. The resulting catalyst was named Cu6Sn5, and its XRD pattern is shown below. Figure 2 .

[0072] Take 25 mg of Cu6Sn5 catalyst and add it to 2500 μL of anhydrous ethanol solvent to prepare a 10 mg / mL solution. -1 The ink-like slurry was then mixed with 150 μL of 5% Nafion solution. The slurry was ultrasonically treated at 60 kHz for 0.5 hours. The carbon paper was then cut into 25 cm pieces. 2 The mixture was then washed with ethanol and deionized water and dried. The prepared slurry was then evenly coated onto carbon paper with a loading of 1 mg / cm². 2 The slurry was completely dried by irradiating it with a 100W infrared lamp for 50 minutes, resulting in a carbon paper-supported Cu6Sn5 electrode.

[0073] The prepared carbon paper-supported Cu6Sn5 electrode was placed as the cathode of a flowing electrolytic cell as the working electrode, and nickel foam was selected as the counter electrode. A proton exchange membrane and 1 mol L⁻¹ were used in between. -1 The KOH electrolyte solution separates the two electrodes. The flow rate is 50 ml / min. -1 An ethylene-rich feed gas containing 0.5% acetylene (20% ethylene, 0.5% acetylene, and the remainder argon) is introduced into the acetylene chamber of the electrocatalytic acetylene hydrogenation reaction system through the inlet. The electrochemical workstation is connected, and the working electrode potentials are set to -0.2V, -0.4V, and -0.6V, respectively. The acetylene gas diffuses to the working electrodes to undergo the electrocatalytic acetylene hydrogenation reaction, selectively hydrogenating acetylene to ethylene. Gas chromatography is used to analyze the acetylene hydrogenation gas products discharged from the acetylene chamber outlet.

[0074] At a reaction potential of -0.2 V, the conversion of the catalyst Cu6Sn5 was 25.4%, the selectivity was 75.4%, and the Faradaic efficiency was 63.5%. At a reaction potential of -0.4 V, the conversion of the catalyst Cu6Sn5 was 41.2%, the selectivity was 87.3%, and the Faradaic efficiency was 81.5%. At a reaction potential of -0.6 V, the conversion of the catalyst Cu6Sn5 was 50.1%, the selectivity was 89.8%, and the Faradaic efficiency was 55.8%. (The last sentence appears to be incomplete and possibly refers to a different reaction timeframe.)-1 Data on the conversion of EASR reactants and the FE (%) of products at the given flow rate using this catalyst are shown in [reference needed]. Figure 1 .

[0075] By comparing catalysts Sn-Cu3Sn1 / Cu, Sn / Cu, Cu6Sn4, and Cu6Sn5 at potentials of -0.2V, -0.4V, and -0.6V for 25cm using Example 1 and Comparative Examples 1-3, the effects of these catalysts on potentials of 25cm at potentials of -0.2V, -0.4V, and -0.6V were investigated. 2 The conversion rate of acetylene, product selectivity, and FE (%) of EASR in the gas chamber were investigated. With increasing surface Sn content, a Sn / Cu catalyst was formed in Sn-Cu3Sn1 / Cu, where Sn coated Cu nanoparticles to form a core-shell structure. This resulted in the Sn / Cu catalyst failing to completely convert acetylene in the ethylene-rich stream. As the thickness of the outer Sn layer increased, the amount of C4 byproduct increased, leading to a decrease in ethylene selectivity. Product formation was directly related to potential. At a potential of -0.2V, the Sn-Cu3Sn1 / Cu catalyst achieved a conversion rate of only 93.5%, which did not meet the requirements for complete acetylene conversion. The optimal reaction conditions for the Sn-Cu3Sn1 / Cu catalyst were -0.4V, with ethylene FE (%) ≥ 86.2% and C2H4 selectivity ≥ 92.9%, achieving complete acetylene conversion.

[0076] Comparative Example 4: Synthesis of Cu Catalyst and Its Application in Electrocatalytic Acetylene Hydrogenation

[0077] Prepare solution A by dissolving 1g of anhydrous copper chloride in 10ml of deionized water, and then prepare 10ml of solution A with a concentration of 5mol / L. -1 A sodium borohydride aqueous solution B was prepared by rapidly adding 10 ml of solution B to 10 ml of solution A at 0 °C and allowing it to stand for 2 hours. The black solid in the solution was collected and then washed several times with water and ethanol. The solid was then dried in a vacuum oven at 40 °C for 12 hours. The resulting catalyst was named Cu, and its XRD pattern is shown below. Figure 2 .Depend on Figure 2 The main diffraction peak positions of the Cu catalyst in the XRD pattern are 43.3, 50.4, and 74.1, which are consistent with the positions on the copper standard card, indicating the successful synthesis of the copper catalyst. The XRD pattern of the Cu catalyst contains a small amount of Cu₂O diffraction peaks, which are inevitably generated by the contact between copper and air during the preparation and testing process.

[0078] Take 25 mg of Cu catalyst and add it to 2500 μL of anhydrous ethanol solvent to prepare a 10 mg / mL solution. -1 The ink-like slurry was then mixed with 150 μL of 5% Nafion solution. The slurry was ultrasonically treated at 60 kHz for 0.5 hours. The carbon paper was then cut into 25 cm pieces. 2The mixture was then washed with ethanol and deionized water and dried. The prepared slurry was then evenly coated onto carbon paper with a loading of 1 mg / cm². 2 The slurry was completely dried by irradiating it with a 100W infrared lamp for 50 minutes, resulting in a carbon paper-supported Cu electrode.

[0079] The prepared carbon paper-supported Cu electrode was placed as the cathode of a flowing electrolytic cell as the working electrode, and nickel foam was selected as the counter electrode. A proton exchange membrane and 1 mol L⁻¹ were used as interlayers. -1 The KOH electrolyte solution separates the two electrodes. The flow rate is 50 ml / min. -1 An ethylene-rich feed gas containing 0.5% acetylene (20% ethylene, 0.5% acetylene, and the remainder argon) is introduced into the acetylene chamber of the electrocatalytic acetylene hydrogenation reaction system through the inlet. The electrochemical workstation is connected, and the working electrode potentials are set to -0.2V, -0.4V, and -0.6V, respectively. The acetylene gas diffuses to the working electrodes to undergo the electrocatalytic acetylene hydrogenation reaction, selectively hydrogenating acetylene to ethylene. Gas chromatography is used to analyze the acetylene hydrogenation gas products discharged from the acetylene chamber outlet.

[0080] At a reaction potential of -0.2 V, the conversion of Cu catalyst was 93.8%, the selectivity was 75.1%, and the Faradaic efficiency was 59.1%. At a reaction potential of -0.4 V, the conversion of Cu catalyst was 100.0%, the selectivity was 82.1%, and the Faradaic efficiency was 47.8%. At a reaction potential of -0.6 V, the conversion of Cu catalyst was 100.0%, the selectivity was 84.7%, and the Faradaic efficiency was 30.9%. (The last sentence appears to be incomplete and requires further context.) -1 Data on the conversion of EASR reactants and the FE (%) of products at the given flow rate using this catalyst are shown in [reference needed]. Figure 1 .

[0081] By comparing Example 1 and Comparative Example 4, the catalyst Sn-Cu3Sn1 / Cu and the catalyst Cu were compared at potentials of -0.2V, -0.4V, and -0.6V for 25cm. 2 The selectivity, FE (%), and acetylene conversion of EASR products in the gas chamber were investigated. At -0.4V, Cu nanoparticles achieved complete conversion of acetylene impurities, but the excellent HER performance of Cu nanoparticles reduced the FE (%) of the ethylene product to 47.8%, limiting the application of copper catalysts in EASR. Sn metal effectively inhibited the HER activity of copper nanoparticles. The C2H4 selectivity of the Sn-Cu3Sn1 / Cu catalyst reached as high as 92.9%. Weak adsorption formed between the Sn termination site and C2H2 made it difficult for carbon-carbon coupling reactions to occur between adjacent activated C2H2 molecules. The highest FE (%) of the Sn-Cu3Sn1 / Cu catalyst reached 86.2%.

[0082] Comparative Example 5: Performance evaluation of Sn-Cu3Sn1 / Cu catalyst under different gas chamber areas

[0083] Cut the carbon paper into 1cm pieces 2 The flow rate of the ethylene-rich feed gas (20% ethylene, 0.5% acetylene, and the remainder being argon) containing 0.5% acetylene was set to 2 ml / min. -1 Except for the synthesis of Sn-Cu3Sn1 / Cu catalyst, the preparation and evaluation of carbon paper supported Sn-Cu3Sn1 / Cu electrode are the same as in Example 1.

[0084] At a reaction potential of -0.2V, the Sn-Cu3Sn1 / Cu catalyst exhibits a conversion of 90.5%, a selectivity of 78.4%, and a Faradaic efficiency of 83.5%. At a reaction potential of -0.4V, the Sn-Cu3Sn1 / Cu catalyst achieves a conversion of 100.0%, a selectivity of 90.9%, and a Faradaic efficiency of 80.2%. At a reaction potential of -0.6V, the Sn-Cu3Sn1 / Cu catalyst... 1 / The Cu catalyst achieved a conversion rate of 100.0%, a selectivity of 92.3%, and a Faraday efficiency of 75.1%.

[0085] By comparing Example 1 and Comparative Example 5, the area of ​​the air chamber increased from 1 cm². 2 Expand to 25cm 2 The Sn-Cu3Sn1 / Cu catalyst achieves a higher removal rate of acetylene impurities. At a potential of -0.4V, the feed gas at 1cm... 2 In the air chamber, 2 ml min -1 Flow rate and at 25cm 2 In the air chamber at 50ml min -1 The flow rate was completely converted to C2H4, with ethylene selectivity greater than 90%. The expanded reactor could increase the gas flow rate from 2 ml / min. -1 Increase to 50ml min -1 This achieves complete removal of C2H2 impurities, meeting production requirements. The results of Example 1 and Comparative Example 5 demonstrate that the Sn-Cu3Sn1 / Cu catalyst shows promising potential for the electrochemical removal of ethylene impurities.

[0086] Comparative Example 6: Performance evaluation of Sn-Cu3Sn1 / Cu catalyst under thermocatalytic acetylene hydrogenation conditions

[0087] The Sn-Cu3Sn1 / Cu catalyst was prepared in the same manner as in Example 1. The performance of the Sn-Cu3Sn1 / Cu catalyst in the selective hydrogenation of acetylene was evaluated in a fixed-bed reactor at atmospheric pressure. The flow rate of the ethylene-rich feed gas (20% ethylene, 0.5% acetylene, 10% hydrogen, and the remainder argon) was controlled at 50 ml / min. -1 The reaction temperature was set to 200℃. Gas chromatography was used to analyze the gaseous products of acetylene hydrogenation. The conversion rate of the Sn-Cu3Sn1 / Cu catalyst was 55.6%, and the selectivity was 40.5%.

[0088] The performance of the Sn-Cu3Sn1 / Cu catalyst under thermocatalytic acetylene hydrogenation and electrocatalytic acetylene hydrogenation conditions was compared using Example 1 and Comparative Example 6. It was found that under electrocatalytic conditions, the Sn-Cu3Sn1 / Cu catalyst exhibits high conversion and selectivity, and does not require hydrogen consumption. This makes it possible for electrocatalytic acetylene hydrogenation technology to replace thermocatalytic acetylene hydrogenation technology.

Claims

1. A Sn-Cu3Sn1 / Cu catalyst, characterized in that: The microstructure of the Sn-Cu3Sn1 / Cu catalyst is that a Cu3Sn1 alloy layer is reconstructed on the surface of copper nanoparticles, and Sn atoms are grown at the Sn sites of the Cu3Sn1 alloy as termination sites. The Sn-Cu3Sn1 / Cu catalyst was prepared according to the following steps: Step 1: Dissolve copper salt and tin salt in water and stir until homogeneous to prepare solution A, wherein the Sn / Cu molar ratio is 0.04-0.06; Step 2: Prepare concentrations between 0.1-10 mol·L⁻¹ -1 Aqueous solution of sodium borohydride B; Step 3: Quickly add sodium borohydride aqueous solution B to solution A at -10℃~25℃ and let it stand for 2-6 hours; Step 4: Collect the solid in the solution, wash and dry to obtain the Sn-Cu3Sn1 / Cu catalyst.

2. A method for preparing the Sn-Cu3Sn1 / Cu catalyst as described in claim 1, characterized in that: The preparation method is carried out according to the following steps: Step 1: Dissolve copper salt and tin salt in water and stir until homogeneous to prepare solution A, wherein the Sn / Cu molar ratio is 0.04-0.06; Step 2: Prepare concentrations between 0.1-10 mol·L⁻¹ -1 Aqueous solution of sodium borohydride B; Step 3: Quickly add sodium borohydride aqueous solution B to solution A at -10℃~25℃ and let it stand for 2-6 hours; Step 4: Collect the solid in the solution, wash and dry to obtain the Sn-Cu3Sn1 / Cu catalyst.

3. The preparation method according to claim 2, characterized in that: The copper salt mentioned in step one is selected from at least one of copper chloride, copper nitrate, copper sulfate, copper phosphate, copper pyrophosphate, basic copper carbonate, and copper acetate; the tin salt is selected from at least one of stannous chloride, stannous tetrachloride, stannous nitrate, and stannous sulfate.

4. An electrode supported on a copper-tin catalyst, characterized in that: The supported copper-tin catalyst electrode is obtained by uniformly mixing a slurry containing the Sn-Cu3Sn1 / Cu catalyst of claim 1 with a 5%-25% Nafion solution, uniformly coating the mixed slurry onto the electrode material, and then drying it.

5. The supported copper-tin catalyst electrode as described in claim 4, characterized in that: The concentration of the slurry containing the Sn-Cu3Sn1 / Cu catalyst is 0.5-10 mg·ml. -1 The volume ratio of the slurry containing the Sn-Cu3Sn1 / Cu catalyst to the Nafion solution is 2500:30~200.

6. The supported copper-tin catalyst electrode as described in claim 5, characterized in that: The concentration of the slurry containing the Sn-Cu3Sn1 / Cu catalyst was 10 mg·ml. -1 The mass fraction of the Nafion solution is 5%, and the volume ratio of the slurry containing the Sn-Cu3Sn1 / Cu catalyst to the volume of the Nafion solution is 2500:

150.

7. The supported copper-tin catalyst electrode according to any one of claims 4-6, characterized in that: The electrode material is at least one of carbon paper, carbon cloth, nickel foam, and copper foam.

8. The supported copper-tin catalyst electrode as described in claim 7, characterized in that: The electrode material is carbon paper, and the loading of the mixed slurry on the carbon paper is 0.1-2 mg / cm³. 2 .

9. The supported copper-tin catalyst electrode as described in claim 8, characterized in that: The loading rate of the mixed slurry on carbon paper is 0.8~1.2 mg / cm. 2 .

10. A method for preparing a copper-tin catalyst supported electrode as described in any one of claims 4-9, characterized in that: The preparation method is carried out according to the following steps: Step A: Add the Sn-Cu3Sn1 / Cu catalyst to the solvent to prepare a solution of 0.5-10 mg·ml. -1 The ink-like slurry is then mixed with 5%-25% Nafion solution by mass, and the mixture is ultrasonically treated to ensure full dispersion. Step B: Wash and dry the cut electrode material; Step C: The mixed slurry obtained in step A is evenly coated onto the electrode material obtained in step B, and then irradiated with an infrared lamp until the slurry is completely dry to obtain a copper-tin catalyst-supported electrode.

11. The application of a copper-tin catalyst electrode as described in any one of claims 4-9 in the selective electrocatalytic hydrogenation of acetylene.

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