A copper-based catalyst, its preparation method and use

Abstract

The present application relates to the field of energy catalysis technology, and particularly relates to a copper-based catalyst and a preparation method and application thereof.The preparation method comprises the following steps: a copper-containing compound and a reducing agent are added into a first solvent, and a suspension containing a Cu2O core is prepared by a solvothermal method; solid-liquid separation treatment is performed on the suspension containing the Cu2O core to obtain Cu2O particles; the Cu2O particles, aniline and ammonium persulfate are added into a second solvent, and a suspension containing a Cu2O@PANI core-shell structure is prepared by in-situ chemical oxidation polymerization; and solid-liquid separation treatment is performed on the suspension containing the Cu2O@PANI core-shell structure to obtain a polyaniline-coated Cu2O catalyst.The copper-based catalyst provided by the present application can be applied to the electrocatalytic reduction of carbon dioxide and / or carbon monoxide to prepare multi-carbon products in an acidic system, and the copper-based catalyst has the advantages of high efficiency, high selectivity and particularly high stability.

Description

Technical Field

[0001] This invention relates to the field of energy catalysis technology, and in particular to a copper-based catalyst, its preparation method, and its application. Background Technology

[0002] Carbon dioxide electrocatalytic reduction technology can use the electricity generated from the conversion of new energy sources to convert carbon dioxide into valuable chemicals. This can not only reduce the content of greenhouse gases in the atmosphere, but also create considerable additional economic benefits.

[0003] The products of the electrocatalytic reduction of carbon dioxide vary depending on the catalyst and other conditions; among them, copper-based catalysts produce ethylene, ethanol, and other C... 2+ The products are valuable chemical raw materials and energy carriers.

[0004] In the more than ten years of development of carbon dioxide electrocatalytic reduction technology, most studies have employed alkaline systems. An alkaline environment allows the hydrogen evolution side reaction at the cathode to proceed at a lower rate and also promotes carbon-carbon coupling at the heterogeneous catalytic interface. However, the electrocatalytic reduction process under alkaline conditions has the following drawbacks:

[0005] (1) Carbon dioxide can react with OH- - The ionic reaction generates carbonates that diffuse towards the anode, which not only reduces the utilization rate of carbon dioxide but also significantly increases the potential of the oxygen evolution reaction at the anode, greatly increasing the energy consumption of the reaction.

[0006] (2) Liquid products such as formate and acetate produced by carbon dioxide reduction will diffuse to the anode through the anion exchange membrane (AEM) under alkaline conditions, resulting in product loss.

[0007] Electrocatalytic reduction under acidic reaction conditions can effectively avoid the problems caused by the above-mentioned defects. On the one hand, under acidic reaction conditions, OH... - The concentration is extremely low, so there is no problem of carbonate formation, and the utilization rate of carbon dioxide can reach 100%; on the other hand, the cation exchange membrane (CEM) used in the acidic system can minimize the loss of liquid products.

[0008] However, acidic systems also have significant drawbacks in the application of carbon dioxide electrocatalytic reduction. Their main disadvantages are a more severe hydrogen evolution side reaction and a lower carbon-carbon coupling reaction rate, which is unfavorable for C… 2+ The generation of products.

[0009] To address this issue in acidic systems, Sargent et al. (Nature 537, 382–386 (2016)) conducted in-depth research on the electrocatalytic reduction of carbon dioxide under acidic conditions, by enriching K on the surface of a copper catalyst.+ Strategies to improve C 2+ The selectivity and stability of the products are further enhanced by introducing Pd to improve local CO coverage, thereby promoting carbon-carbon coupling. However, in these studies, copper-based catalysts showed severe corrosion and spalling in acidic electrolytes, and their stability was generally poor.

[0010] In summary, developing a highly efficient, selective, and stable catalyst suitable for the electrocatalytic reduction of carbon dioxide to produce multi-carbon products in acidic systems is of paramount importance and is precisely the technical problem that those skilled in the art are dedicated to solving. Summary of the Invention

[0011] To address the shortcomings of the prior art mentioned in the background section, this invention provides a copper-based catalyst, its preparation method, and its application. The prepared catalyst can be used to electroreduced carbon dioxide and / or carbon monoxide in an acidic system to prepare multi-carbon products, and has the advantages of high efficiency, high selectivity, and especially high stability.

[0012] The preparation method of the copper-based catalyst provided by this invention is as follows:

[0013] The preparation method of this copper-based catalyst includes the following steps:

[0014] A copper-containing compound and a reducing agent are added to a first solvent, and a suspension containing Cu2O cores is prepared by a solvothermal method; the suspension containing Cu2O cores is subjected to solid-liquid separation treatment to obtain Cu2O particles;

[0015] The Cu2O particles, aniline, and ammonium persulfate are added to a second solvent, and a polymerization reaction is carried out by in-situ chemical oxidation to obtain a suspension containing a Cu2O@PANI core-shell structure. The Cu2O@PANI core-shell structure suspension is subjected to solid-liquid separation treatment to obtain a polyaniline-coated Cu2O catalyst.

[0016] In one embodiment, the following steps are included:

[0017] The copper-containing compound is dissolved in the first solvent to prepare solution A;

[0018] A reducing agent was added to solution A and heated to obtain suspension B containing Cu2O cores;

[0019] The suspension containing Cu2O cores was subjected to impurity removal and solid-liquid separation treatment to obtain Cu2O particles;

[0020] The Cu2O particles were added to a second solvent to prepare suspension C;

[0021] Aniline and ammonium persulfate were added to the suspension C to carry out a polymerization reaction to obtain a suspension containing a Cu2O@PANI core-shell structure;

[0022] The suspension containing the Cu2O@PANI core-shell structure was subjected to impurity removal and solid-liquid separation treatment to obtain the polyaniline-coated Cu2O catalyst.

[0023] In one embodiment, the copper-containing compound includes at least one of copper acetate, copper sulfate, copper nitrate, copper halide, and copper acetylacetonate; the first solvent includes at least one of ethanol, methanol, n-propanol, isopropanol, and water; and the mass percentage concentration of the copper-containing compound in solution A is 0.5% to 15%.

[0024] In one embodiment, a reducing agent is added to solution A and stirred for 0.5 to 1.5 hours, then sealed and heated to a system temperature of 120°C to 200°C for 1 to 20 hours to obtain a suspension B containing Cu2O cores; wherein the reducing agent includes at least one of glucose, ascorbic acid, sodium citrate, and hydrazine hydrate; and the molar ratio of Cu ions in the copper-containing compound to the reducing agent is 1:(0.05 to 5).

[0025] In one embodiment, the second solvent is water; the mass ratio of the Cu2O particles to the second solvent is (0.0005~0.005):1.

[0026] In one embodiment, aniline is added to the suspension C and stirred for 0.5–1.5 h, followed by the addition of ammonium persulfate for a polymerization reaction of 2–10 h to obtain the suspension containing the Cu2O@PANI core-shell structure; wherein the polymerization reaction temperature is controlled at 0–25 °C; wherein the molar ratio of aniline to Cu2O particles in suspension C is (0.05–5):1; the molar ratio of ammonium persulfate to Cu2O particles in suspension C is (0.05–5):1; and the molar ratio of aniline to ammonium persulfate is (0.2–5):1.

[0027] The present invention also provides a copper-based catalyst, which is prepared by the preparation method described above.

[0028] The present invention also provides an application of a copper-based catalyst, wherein the copper-based catalyst is used to prepare multi-carbon products by electroreduction of carbon dioxide and / or carbon monoxide in an acidic system, and the copper-based catalyst is used as a cathode in a flowing electrolyzer; wherein the copper-based catalyst is prepared by the preparation method described above.

[0029] In one embodiment, an electroreduction reaction is carried out in a flowing electrolytic cell. Gas is introduced into the cathode, and electrolysis is performed by applying a negative potential or negative current to produce a multi-carbon product. The gas is carbon dioxide and / or carbon monoxide, the cathode is the copper-based catalyst, the anode is at least one of iridium dioxide, titanium mesh, and titanium foam, and a saturated Ag / AgCl electrode is used as a reference electrode.

[0030] In one embodiment, in the electroreduction reaction of the flowing electrolytic cell, the gas flow rate is 1–100 mL / min. -1 The electrolyte comprises a solution of acidic substances, a solution of salts, or a mixed solution of acidic and salt substances; the concentration of the electrolyte is 0.01–10 mol·L⁻¹. -1 pH value less than 7; negative potential of -0.2V to -1.5V vs. RHE; negative current density of 50 to 2000 mA·cm⁻¹ -2 The multicarbon product includes at least one of ethylene, ethanol, acetic acid, and n-propanol.

[0031] Based on the above, compared with the prior art, the present invention has the following beneficial effects:

[0032] This invention provides a copper-based catalyst and its preparation method. The copper-based catalyst is applicable to the electrocatalytic reduction of carbon dioxide and / or carbon monoxide in acidic systems to prepare multi-carbon products. It has the advantages of high efficiency, high selectivity, and especially high stability.

[0033] Other features and beneficial effects of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other beneficial effects of the invention can be realized and obtained by means of the structures particularly pointed out in the description, claims and drawings. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Unless otherwise specified, the positional relationships shown in the drawings in the following description are based on the direction in which the components are drawn in the figure.

[0035] Figure 1 The X-ray diffraction patterns of Cu2O@PANI and Cu2O catalysts synthesized in Example 1 and Comparative Example 1 before and after the CO2 electroreduction reaction are shown.

[0036] Figure 2This is a scanning electron microscope image of the Cu2O@PANI catalyst synthesized in Example 1;

[0037] Figure 3 This is a transmission electron microscope (TEM) image of the Cu2O@PANI catalyst synthesized in Example 1.

[0038] Figure 4 This is a schematic diagram of the flow electrolysis cell device used for electroreduction and performance evaluation in this invention;

[0039] Figure 5 The diagram shows the cathode potential and product selectivity of the Cu2O@PANI catalysts synthesized in Examples 1 and 4 when applied to the electrocatalytic reduction of carbon dioxide at different current densities.

[0040] Figure 6 The graph shows the product selectivity and CO2 conversion rate of the Cu2O@PANI catalyst synthesized in Example 5 when applied to the electrocatalytic reduction of carbon dioxide at different CO2 gas flow rates.

[0041] Figure 7 When the Cu2O@PANI catalyst in Example 6 and the Cu2O catalyst in Comparative Example 1 are applied to the electrocatalytic reduction of carbon dioxide, at 200 mA·cm -2 Comparison of stability tests under current density;

[0042] Figure 8 When PANI@Cu in Comparative Example 2 and Cu catalyst in Comparative Example 3 are applied to the electrocatalytic reduction of carbon dioxide at 200 mA·cm⁻¹ -2 Comparison of stability tests under current density;

[0043] Figure 9 The diagram shows the cathode potential and product selectivity at different current densities when the Cu2O@PANI catalyst synthesized in Example 7 is applied to the electrocatalytic reduction of carbon monoxide.

[0044] Figure 10 When the Cu2O@PANI catalyst in Example 8 and the Cu2O catalyst in Comparative Example 4 are applied to the electrocatalytic reduction of carbon monoxide, at 300 mA·cm⁻¹ -2 Comparison of stability tests under current density;

[0045] Figure 11 The diagram shows the cathode potential and product selectivity at different current densities when the Cu2O catalyst synthesized in Comparative Example 4 is applied to the electrocatalytic reduction of carbon monoxide.

[0046] Figure label:

[0047] 10 Reference electrode 20 Ion exchange membrane 30 Electrolyte

[0048] 40 gas diffusion layer 50 anode Detailed Implementation

[0049] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. The technical features designed in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0050] In the description of this invention, it should be noted that all terms used in this invention (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains, and should not be construed as limiting the invention; it should be further understood that the terms used in this invention should be understood to have the same meaning as those in the context of this specification and in the relevant field, and should not be understood in an idealized or overly formal sense, except as expressly defined in this invention.

[0051] The method for preparing the copper-based catalyst provided by this invention specifically includes the following preparation steps:

[0052] (1) Dissolve the copper-containing compound in the first solvent to prepare solution A;

[0053] (2) Add a reducing agent to the solution A and heat it to obtain a suspension B containing Cu2O cores;

[0054] (3) The suspension containing Cu2O cores is subjected to impurity removal and solid-liquid separation treatment to obtain Cu2O particles;

[0055] (4) The Cu2O particles are added to the second solvent to prepare a suspension C;

[0056] (5) Add aniline and ammonium persulfate to the suspension C and carry out a polymerization reaction to obtain a suspension containing Cu2O@PANI core-shell structure;

[0057] (6) The suspension containing the Cu2O@PANI core-shell structure is subjected to impurity removal and solid-liquid separation treatment to obtain the polyaniline-coated Cu2O catalyst, namely the copper-based catalyst.

[0058] For step (1):

[0059] The copper-containing compound is preferably at least one of copper acetate, copper sulfate, copper nitrate, copper halide, and copper acetylacetonate; the first solvent is preferably at least one of ethanol, methanol, n-propanol, isopropanol, and water; the mass percentage concentration of the copper-containing compound in solution A is preferably 0.5% to 15%.

[0060] For step (2):

[0061] Preferably, after adding a reducing agent to solution A and stirring for 0.5 to 1.5 hours, the solution is sealed and heated to a system temperature of 120°C to 200°C for 1 to 20 hours to obtain a suspension B containing Cu2O cores.

[0062] The reducing agent is preferably at least one of glucose, ascorbic acid, sodium citrate, and hydrazine hydrate; the molar ratio of Cu ions in the copper-containing compound to the reducing agent is preferably 1:(0.05-5).

[0063] For step (4):

[0064] The second solvent is preferably water; the mass ratio of the Cu2O particles to the second solvent is preferably (0.0005~0.005):1.

[0065] For step (5):

[0066] Preferably, aniline is added to the suspension C and stirred for 0.5 to 1.5 h, and then ammonium persulfate is added to carry out a polymerization reaction for 2 to 10 h to obtain a suspension containing a Cu2O@PANI core-shell structure; wherein, the polymerization reaction temperature is controlled at 0 to 25°C, preferably 0°C;

[0067] The molar ratio of aniline to Cu2O particles in suspension C is (0.05–5):1; the molar ratio of ammonium persulfate to Cu2O particles in suspension C is (0.05–5):1; and the molar ratio of aniline to ammonium persulfate is (0.2–5):1. Preferably, the molar ratio of aniline to Cu2O particles in suspension C is less than 1.3:1, more preferably (0.1–0.6):1. Preferably, the molar ratio of aniline to ammonium persulfate is 1:1.

[0068] Furthermore, this invention also provides an application of the aforementioned copper-based catalyst, wherein the copper-based catalyst is used in the electroreduction of carbon dioxide to prepare multi-carbon products under acidic conditions, and the copper-based catalyst is used as the cathode in a flowing electrolyzer. This invention also provides an example of the application of this copper-based catalyst in the electroreduction of carbon dioxide to prepare multi-carbon products under acidic conditions, the specific steps of which are as follows: Figure 4 As shown, an electroreduction reaction is carried out in a flowing electrolytic cell by passing carbon dioxide gas into the cathode and applying a negative potential or negative current to perform electrolysis, thereby producing a multi-carbon product.

[0069] In this configuration, the copper-based catalyst serves as the cathode, the anode 50 is at least one of iridium dioxide, titanium mesh, and titanium foam, and the saturated Ag / AgCl electrode serves as the reference electrode 10. Preferably, in the electroreduction reaction of the flowing electrolytic cell, the flow rate of the carbon dioxide gas is 1–100 mL / min. -1 Electrolyte 30 is a solution of an acid, a solution of a salt, or a mixed solution of an acid and a salt. The acid includes, but is not limited to, one or more combinations of sulfuric acid, carbonic acid, and phosphoric acid. The salt includes, but is not limited to, one or more combinations of sulfates, carbonates, and phosphates. The concentration of electrolyte 30 is 0.01–10 mol·L⁻¹. -1 Furthermore, its pH value is less than 7; its negative potential is -0.2V to -1.5V vs. RHE, and its negative current density is 50 to 2000 mA·cm⁻¹. -2 The multi-carbon product includes at least one of ethylene, ethanol, acetic acid, and n-propanol. More preferably, the gas flow rate is 5–100 mL / min. -1 The current density of the negative current is 500 mA·cm. -2 .

[0070] It should be noted that the inventors of this application have discovered that, based on the above-mentioned catalyst application concept, the copper-based catalyst prepared in this application can also be used as a cathode in a flowing electrolytic cell, applied to the electrocatalytic reduction of carbon monoxide gas to prepare multi-carbon products in an acidic system, or applied to the electrocatalytic reduction of a mixture of carbon monoxide and carbon dioxide gas to prepare multi-carbon products in an acidic system.

[0071] This invention also provides an example of applying the copper-based catalyst to the electroreduction of carbon monoxide in an acidic system to prepare multi-carbon products, the specific steps of which are as follows: Figure 4 As shown, an electroreduction reaction is carried out in a flowing electrolytic cell. Carbon monoxide gas is introduced into the cathode, and electrolysis is performed by applying a negative potential or negative current, thus producing a multi-carbon product.

[0072] In this configuration, the copper-based catalyst serves as the cathode, the anode 50 is at least one of iridium dioxide, titanium mesh, and titanium foam, and the saturated Ag / AgCl electrode serves as the reference electrode 10. Preferably, in the electroreduction reaction of the flowing electrolytic cell, the flow rate of the carbon monoxide gas is 1–100 mL / min. -1 Electrolyte 30 is a solution of an acid, a solution of a salt, or a mixed solution of an acid and a salt. The acid includes, but is not limited to, one or more combinations of sulfuric acid, carbonic acid, and phosphoric acid. The salt includes, but is not limited to, one or more combinations of sulfates, carbonates, and phosphates. The concentration of electrolyte 30 is 0.01–10 mol·L⁻¹. -1Furthermore, its pH value is less than 7; its negative potential is -0.2V to -1.5V vs. RHE, and its negative current density is 50 to 2000 mA·cm⁻¹. -2 The multi-carbon product includes at least one of ethylene, ethanol, acetic acid, and n-propanol. Preferably, the current density of the negative current is 100–500 mA·cm⁻¹. -2 More preferably, the current density of the negative current is 300 mA·cm. -2 .

[0073] The present invention also provides the following embodiments and comparative examples to verify the technical effects of the present invention:

[0074] Example 1

[0075] Weigh 1.4 g of Cu(Ac)₂·H₂O and add it to 50 mL of anhydrous ethanol solution. Stir vigorously for 60 min, then add 0.09 g of C₆H₂O. 12 After stirring with O6·H2O for 60 min, the mixture was transferred to a 100 mL reactor. The reactor was sealed and placed in an oven to be heated to 140 °C and maintained for 2 h. After naturally cooling to room temperature, the mixture was washed with ethanol and water, centrifuged, and freeze-dried overnight under vacuum to obtain the Cu2O catalyst.

[0076] Weigh 100 mg of the Cu2O catalyst synthesized according to the above method, add 100 mL of deionized water, sonicate for 20 min, add 28 μL of aniline in an ice bath at 0 °C with vigorous stirring, continue stirring for 30 min, and then add a certain amount of ammonium persulfate to make the molar ratio of aniline to ammonium persulfate 1:1. Polymerize for 5 h, and finally wash with ethanol and water three times, centrifuge three times, freeze-dry and collect the Cu2O@PANI catalyst sample.

[0077] The synthesized Cu₂O@PANI catalyst sample was applied to the electroreduction of carbon dioxide and / or carbon monoxide in an acidic system to prepare multi-carbon products, serving as the cathode in a flow electrolyzer. A schematic diagram of the flow electrolyzer is shown below. Figure 4 As shown, it includes components and structures such as a reference electrode 10, an ion exchange membrane 20, an electrolyte 30, a gas diffusion layer 40, and an anode 50. In use, the synthesized Cu₂O@PANI catalyst sample is loaded onto the gas diffusion layer 40 at a loading rate of 1.0 mg·cm⁻¹. -2 Using this catalyst as the cathode, a titanium mesh supported on iridium dioxide as the anode 50, and a saturated Ag / AgCl electrode as the reference electrode 10, the reaction is carried out in a three-electrode flow electrolysis cell.

[0078] The electrolyte 30 is a mixture of 0.5 M K2SO4 and H2SO4 (pH=3), and the cathode carbon dioxide gas flow rate is 50 mL·min. -1Apply a negative current, making the current density 500 mA·cm. -2 At this point, the cathode potential is -1.10V vs. RHE. After reacting for 10 minutes, C 2+ The product has a Faraday efficiency of 75.4%, specifically as follows: Figure 5 As shown.

[0079] Example 2

[0080] Weigh 1.4 g of Cu(Ac)₂·H₂O and add it to 50 mL of anhydrous ethanol solution. Stir vigorously for 60 min, then add 0.09 g of C₆H₂O. 12 After stirring with O6·H2O for 60 min, the mixture was transferred to a 100 mL reactor. The reactor was sealed and placed in an oven to be heated to 140 °C and maintained for 2 h. After naturally cooling to room temperature, the mixture was washed with ethanol and water, centrifuged, and freeze-dried overnight under vacuum to obtain the Cu2O catalyst.

[0081] Weigh 100 mg of the Cu2O catalyst synthesized according to the above method, add 100 mL of deionized water, sonicate for 20 min, add 14 μL of aniline in an ice bath at 0 °C with vigorous stirring, continue stirring for 30 min, and then add a certain amount of ammonium persulfate to make the molar ratio of aniline to ammonium persulfate 1:1. The polymerization reaction is carried out for 5 h, and finally the sample is washed three times with ethanol and water respectively, centrifuged, and freeze-dried to collect the Cu2O@PANI catalyst sample.

[0082] The synthesized Cu₂O@PANI catalyst sample was loaded onto gas diffusion layer 40 at a loading rate of 1.0 mg·cm⁻¹. -2 Using this catalyst as the cathode, a titanium mesh supported on iridium dioxide as the anode 50, and a saturated Ag / AgCl electrode as the reference electrode 10, the reaction is carried out in a three-electrode flow electrolytic cell. A schematic diagram of the electrolytic cell is shown below. Figure 4 As shown;

[0083] Electrolyte 30 is a mixture of 0.5 M K2SO4 and H2SO4 (pH=3), and the cathode carbon dioxide gas flow rate is 50 mL·min. -1 Apply a negative current, making the current density 500 mA·cm. -2 At this point, the cathode potential is -1.17V vs. RHE. After 10 minutes of reaction, C 2+ The product has a Faraday efficiency of 62.6%.

[0084] Example 3

[0085] Weigh 1.4 g of Cu(Ac)₂·H₂O and add it to 50 mL of anhydrous ethanol solution. Stir vigorously for 60 min, then add 0.09 g of C₆H₂O. 12After stirring with O6·H2O for 60 min, the mixture was transferred to a 100 mL reactor. The reactor was sealed and placed in an oven to be heated to 140 °C and maintained for 2 h. After naturally cooling to room temperature, the mixture was washed with ethanol and water, centrifuged, and freeze-dried overnight under vacuum to obtain the Cu2O catalyst.

[0086] Weigh 100 mg of the Cu2O catalyst synthesized according to the above method, add 100 mL of deionized water, sonicate for 20 min, add 85 μL of aniline under 0℃ ice bath and vigorous stirring, continue stirring for 30 min, and then add a certain amount of ammonium persulfate to make the molar ratio of aniline to ammonium persulfate 1:1. Polymerize for 5 h, and finally wash with ethanol and water three times, centrifuge three times, freeze-dry and collect the Cu2O@PANI catalyst sample.

[0087] The synthesized Cu₂O@PANI catalyst sample was loaded onto gas diffusion layer 40 at a loading rate of 1.0 mg·cm⁻¹. -2 Using this catalyst as the cathode, a titanium mesh supported on iridium dioxide as the anode 50, and a saturated Ag / AgCl electrode as the reference electrode 10, the reaction is carried out in a three-electrode flow electrolytic cell. A schematic diagram of the electrolytic cell is shown below. Figure 4 As shown;

[0088] Electrolyte 30 is a mixture of 0.5 M K2SO4 and H2SO4 (pH=3), and the cathode carbon dioxide gas flow rate is 50 mL·min. -1 Apply a negative current, making the current density 500 mA·cm. -2 At this point, the cathode potential is -1.28V vs. RHE. After a reaction of 10 minutes, C 2+ The product has a Faraday efficiency of 52.3%.

[0089] Example 4

[0090] The synthesis process and parameters of the Cu2O@PANI catalyst sample are the same as those in Example 1.

[0091] The synthesized Cu₂O@PANI catalyst sample was loaded onto gas diffusion layer 40 at a loading rate of 1.0 mg·cm⁻¹. -2 Using this catalyst as the cathode, a titanium mesh supported on iridium dioxide as the anode 50, and a saturated Ag / AgCl electrode as the reference electrode 10, the reaction is carried out in a three-electrode flow electrolytic cell. A schematic diagram of the electrolytic cell is shown below. Figure 4 As shown;

[0092] The electrolyte 30 is a mixture of 0.5 M K2SO4 and H2SO4 (pH=3), and the cathode carbon dioxide gas flow rate is 50 mL·min. -1 Apply negative currents with current densities of 50, 100, 300, 700, and 1000 mA·cm⁻¹.-2 At this point, the cathode potentials were -0.57, -0.77, -0.92, -1.22, and -1.38 V vs. RHE, respectively. After 10 min of reaction, C 2+ The Faraday efficiencies of the products were 30.4%, 46.4%, 61.1%, 73.1%, and 68.7%, respectively. Figure 5 As shown.

[0093] Example 5

[0094] The synthesis process and parameters of the Cu2O@PANI catalyst sample are the same as those in Example 1.

[0095] The synthesized Cu₂O@PANI catalyst sample was loaded onto gas diffusion layer 40 at a loading rate of 1.0 mg·cm⁻¹. -2 Using this catalyst as the cathode, a titanium mesh supported on iridium dioxide as the anode 50, and a saturated Ag / AgCl electrode as the reference electrode 10, the reaction is carried out in a three-electrode flow electrolytic cell. A schematic diagram of the electrolytic cell is shown below. Figure 4 As shown;

[0096] Electrolyte 30 is a mixture of 0.5 M K2SO4 and H2SO4 (pH=3), and the cathode carbon dioxide gas flow rates are 3, 5, 10, 20, 35, and 50 mL·min. -1 Apply a negative current to make the current density 700 mA·cm. -2 At this point, the cathode potential is -1.22V vs. RHE. After reacting for 10 minutes, C 2+ The Faraday efficiencies of the products were 40.8, 68.4, 67.4, 70.4, 67.8, and 73.9%, respectively, and the CO2 conversion rates were 35.5%, 40.5%, 19.4%, 10.9%, 6.16%, and 4.57%, respectively. Figure 6 As shown.

[0097] Test results show that at a lower CO2 flow rate (3 mL·min), -1 Under these conditions, the product is mainly H2, and C 2+ The product Faraday efficiency was low (40.8%); when the CO2 flow rate increased to 5 mL·min -1 C 2+ The product Faraday efficiency is significantly increased; further increasing the CO2 flow rate, C 2+ Faraday efficiency showed no significant increase. At lower CO2 flow rates (3 mL·min⁻¹), -1 Or 5 mL·min -1 At the specified conditions, the CO2 conversion rate is relatively high (35.5%, 40.5%); further increasing the CO2 flow rate causes the CO2 conversion rate to decrease sharply.

[0098] Example 6

[0099] The synthesis process and parameters of the Cu2O@PANI catalyst sample are the same as those in Example 1.

[0100] The synthesized Cu₂O@PANI catalyst sample was loaded onto gas diffusion layer 40 at a loading rate of 1.0 mg·cm⁻¹. -2 Using this catalyst as the cathode, a titanium mesh supported on iridium dioxide as the anode 50, and a saturated Ag / AgCl electrode as the reference electrode 10, the reaction is carried out in a three-electrode flow electrolytic cell. A schematic diagram of the electrolytic cell is shown below. Figure 4 As shown;

[0101] The electrolyte 30 is a mixture of 0.5 M K2SO4 and H2SO4 (pH=3), and the cathode carbon dioxide gas flow rate is 50 mL·min. -1 Apply a negative current, making the current density 200 mA·cm⁻¹ -2 The reaction lasted 120 hours at C. 2+ The selectivity of the product can be maintained at over 60%, such as Figure 7 As shown.

[0102] Example 7

[0103] The synthesis process and parameters of the Cu2O@PANI catalyst sample are the same as those in Example 1.

[0104] The Cu2O@PANI catalyst synthesized in this example was applied to the electrocatalytic reduction of carbon monoxide to prepare multi-carbon products: the synthesized Cu2O@PANI catalyst sample was loaded onto the gas diffusion layer 40 with a loading amount of 1.0 mg·cm³. -2 Using this catalyst as the cathode, a titanium mesh supported on iridium dioxide as the anode 50, and a saturated Ag / AgCl electrode as the reference electrode 10, the reaction is carried out in a three-electrode flow electrolytic cell. A schematic diagram of the flow electrolytic cell is shown below. Figure 4 As shown;

[0105] Electrolyte 30 is a mixture of 0.5M K2SO4 and H2SO4 (pH=3), and the cathode carbon monoxide gas flow rate is 50 mL·min. -1 A negative current is applied, with current densities of 20, 50, 100, 300, 500, 700, 1000, 1200, and 1700 mA·cm⁻¹. -2 At this point, the cathode potentials were -0.34, -0.38, -0.42, -0.48, -0.55, -0.62, -0.79, -0.91, and -1.11 V, respectively, compared to RHE. After 10 min of reaction, C 2+The Faraday efficiencies of the products were 55.4%, 74.6%, 87.8%, 88.8%, 80.5%, 78.2%, 73.8%, 75.9%, and 61.4%, respectively. Figure 9 As shown.

[0106] Example 8

[0107] The synthesis process and parameters of the Cu2O@PANI catalyst sample are the same as those in Example 1.

[0108] The Cu2O@PANI catalyst synthesized in this example was applied to the electrocatalytic reduction of carbon monoxide to prepare multi-carbon products: the synthesized Cu2O@PANI catalyst sample was loaded onto the gas diffusion layer 40 with a loading amount of 1.0 mg·cm³. -2 Using this catalyst as the cathode, a titanium mesh supported on iridium dioxide as the anode 50, and a saturated Ag / AgCl electrode as the reference electrode 10, the reaction is carried out in a three-electrode flow electrolytic cell. A schematic diagram of the electrolytic cell is shown below. Figure 4 As shown;

[0109] Electrolyte 30 is a mixture of 0.5M K2SO4 and H2SO4 (pH=3), and the cathode carbon monoxide gas flow rate is 50 mL·min. -1 Apply a negative current to make the current density 300 mA·cm. -2 The reaction lasted for 25 hours, at C 2+ The selectivity of the product can be maintained at over 80%, such as Figure 10 As shown.

[0110] Comparative Example 1:

[0111] Weigh 1.4 g of Cu(Ac)₂·H₂O and add it to 50 mL of anhydrous ethanol solution. Stir vigorously for 60 min, then add 0.09 g of C₆H₂O. 12 After stirring with O6·H2O for 60 min, the mixture was transferred to a 100 mL reactor. The reactor was sealed and placed in an oven to be heated to 140 °C and maintained for 2 h. After naturally cooling to room temperature, the mixture was washed with ethanol and water, centrifuged, and freeze-dried overnight under vacuum to obtain the Cu2O catalyst.

[0112] The Cu₂O catalyst synthesized in this comparative example was applied to the electrocatalytic reduction of carbon dioxide to prepare multi-carbon products: the synthesized Cu₂O catalyst sample was supported on a gas diffusion layer 40 with a loading of 1.0 mg·cm⁻¹. -2 Using this catalyst as the cathode, a titanium mesh supported on iridium dioxide as the anode 50, and a saturated Ag / AgCl electrode as the reference electrode 10, the reaction is carried out in a three-electrode flow electrolytic cell. A schematic diagram of the electrolytic cell is shown below. Figure 4As shown; wherein, electrolyte 30 is a mixture of 0.5 M K2SO4 and H2SO4 (pH=3), and the cathode carbon dioxide gas flow rate is 50 mL·min. -1 Apply a negative current, making the current density 500 mA·cm. -2 At this point, the cathode potential is -1.27V vs. RHE. After 10 minutes of reaction, C 2+ The product's Faraday efficiency is approximately 61.9%. A negative current is then applied, resulting in a current density of 200 mA·cm⁻¹. -2 At the initial stage of the reaction, C 2+ The product selectivity is around 43%, the reaction time is 17 hours, and the concentration is C. 2+ The selectivity of the product decreased rapidly after 12 hours, eventually remaining at less than 20%. Figure 7 As shown.

[0113] Comparative Example 2:

[0114] Weigh 100 mg of elemental copper catalyst (commercial product), add 100 mL of deionized water, sonicate for 20 min, add 28 μL of aniline in an ice bath at 0 °C with vigorous stirring, continue stirring for 30 min, then add a certain amount of ammonium persulfate to make the molar ratio of aniline to ammonium persulfate 1:1. Incubate the polymerization reaction for 5 h, then wash three times with ethanol and water respectively, centrifuge, and freeze-dry to collect the Cu@PANI catalyst sample.

[0115] The synthesized Cu@PANI catalyst sample was loaded onto gas diffusion layer 40 at a loading rate of 1.0 mg·cm⁻¹. -2 Using this catalyst as the cathode, a titanium mesh supported on iridium dioxide as the anode 50, and a saturated Ag / AgCl electrode as the reference electrode 10, the reaction is carried out in a three-electrode flow electrolytic cell. A schematic diagram of the electrolytic cell is shown below. Figure 4 As shown;

[0116] The electrolyte 30 is a mixture of 0.5 M K2SO4 and H2SO4 (pH=3), and the cathode carbon dioxide gas flow rate is 50 mL·min. -1 Apply a negative current, making the current density 500 mA·cm. -2 At this point, the cathode potential is -1.09V vs. RHE. After 10 minutes of reaction, C 2+ The product's Faraday efficiency is approximately 42.8%. A negative current is then applied, resulting in a current density of 200 mA·cm⁻¹. -2 The reaction lasted for 30 hours, at C 2+ The selectivity of the product can be consistently maintained above 20%, such as Figure 8 As shown.

[0117] Comparative Example 3:

[0118] The elemental copper catalyst sample was loaded onto the gas diffusion layer 40 at a loading rate of 1.0 mg·cm³. -2 Using this catalyst as the cathode, a titanium mesh supported on iridium dioxide as the anode 50, and a saturated Ag / AgCl electrode as the reference electrode 10, the reaction is carried out in a three-electrode flow electrolytic cell. A schematic diagram of the electrolytic cell is shown below. Figure 4 As shown; the electrolyte 30 at anode 5 is a mixture of 0.5 Mk2SO4 and H2SO4 (pH=3), and the carbon dioxide gas flow rate at cathode is 50 mL·min. -1 Apply a negative current, making the current density 500 mA·cm. -2 At this point, the cathode potential is -1.04V vs. RHE. After 10 minutes of reaction, C 2+ The Faraday efficiency of the product is approximately 43%. Additionally, a negative current is applied, resulting in a current density of 200 mA·cm⁻¹. -2 The elemental copper catalyst deactivates rapidly within 2.5 hours, such as... Figure 8 As shown.

[0119] Comparative Example 4:

[0120] The synthesis process and parameters of the Cu2O catalyst sample were the same as those of Comparative Example 1.

[0121] The synthesized Cu₂O catalyst sample was loaded onto the gas diffusion layer 40 with a loading amount of 1.0 mg·cm⁻¹. -2 Using this catalyst as the cathode, a titanium mesh supported on iridium dioxide as the anode 50, and a saturated Ag / AgCl electrode as the reference electrode 10, the reaction is carried out in a three-electrode flow electrolytic cell. A schematic diagram of the electrolytic cell is shown below. Figure 4 As shown; wherein, electrolyte 30 is a mixture of 0.5M K2SO4 and H2SO4 (pH=3), and the cathode carbon monoxide gas flow rate is 50 mL·min. -1 A negative current is applied, with current densities of 20, 50, 100, 300, 500, 700, 800, 1200, and 1500 mA·cm⁻¹, respectively. -2 At this point, the cathode potentials were -0.36, -0.40, -0.44, -0.49, -0.60, -0.76, -0.94, -1.12, and -1.23 V, respectively, compared to RHE. After reacting for 10 minutes, C... 2+ The Faraday efficiencies of the products were 52.0, 69.5, 76.1, 80.7, 70.9, 57.0, 50.4, 47.9, and 39.9%, respectively. Figure 11 As shown.

[0122] In addition, a negative current is applied, making the current density 300 mA·cm. -2 At the initial stage of the reaction, C 2+The product selectivity is around 80%, the reaction time is 5 hours, and the concentration is C. 2+ The selectivity of the product decreased rapidly after 3 hours, eventually remaining at less than 30%. Figure 10 As shown.

[0123] In summary, the test results of the above comparative examples and embodiments are shown in Table 1 below:

[0124] Table 1

[0125]

[0126]

[0127] Analyzing the test results of the above embodiments and comparative examples, it can be seen that:

[0128] (1) Test results of Examples 1-3:

[0129] The XRD image of the catalyst sample synthesized in Example 1 is shown below. Figure 1 As shown, Figure 1 As can be seen, the precursor is Cu₂O, and the phase changes to Cu after the electroreduction reaction; the SEM and TEM images of the sample are shown below. Figure 2 , Figure 3 As shown, Figures 2-3 As can be seen, the Cu₂O particle size is approximately 2 μm, while the PANI coating thickness is 8–12 nm. The PANI coating has an amorphous structure, with the main exposed surface of Cu being... Figure 3 The exposed crystal plane 111 is shown.

[0130] When the catalyst is used for the electrocatalytic reduction of carbon dioxide, the thickness of the polyaniline coating layer has a certain impact on the performance of the carbon dioxide electrocatalytic reduction reaction. Both a smaller amount of polyaniline coating (Example 2: 14% PANI-Cu2O) and a larger amount of polyaniline coating (Example 1: 28% PANI-Cu2O) can improve the CO2RR activity and increase the current density. 2+ The product selectivity increased, while the C1 product selectivity decreased, and the enhancing effect became more significant with increasing polyaniline coating content. However, excessive polyaniline coating (Example 3: 85% PANI-Cu2O) did not improve catalyst performance; the catalyst C... 2+ The product selectivity was only 52.3%, even lower than that of the pure Cu2O catalyst in Comparative Example 1. This may be because an excessively thick capping layer would inhibit the formation of active sites.

[0131] (2) Comparison of the test results of Examples 1 and 4:

[0132] The test results of Examples 1 and 4 show that when the catalyst is applied to the electrocatalytic reduction of carbon dioxide, in Example 4, the current densities are 50, 100, 300, 700, and 1000 mA·cm⁻¹, respectively. -2 When, the corresponding C 2+ The Faraday efficiencies of the products were 30.4%, 46.4%, 61.1%, 73.1%, and 68.7%, respectively. This indicates that when a relatively small current density is applied, C... 2+ The product has low Faraday efficiency; as the applied current density increases, the cathode potential increases, and C... 2+ The selectivity of the product gradually increased; the current density in Example 1 was 500 mA·cm. -2 C 2+ The product has a Faraday efficiency of 75.4%, indicating that at a current density of 500 mA·cm⁻¹, the efficiency is high. -2 At that time, C 2+ The product selectivity was highest, reaching 75.4%, while further increasing the current density, C 2+ Product selectivity decreased.

[0133] (3) Comparison of test results of Example 5 at different cathode carbon dioxide gas flow rates:

[0134] When the catalyst was applied to the electrocatalytic reduction of carbon dioxide, test results showed that at a lower CO2 flow rate (3 mL·min), -1 Under these conditions, the product is mainly H2, and C 2+ The product Faraday efficiency was low (40.8%); when the CO2 flow rate increased to 5 mL·min -1 C 2+ The product Faraday efficiency increased significantly; then, by further increasing the CO2 flow rate, C 2+ Faraday efficiency did not increase significantly.

[0135] (4) Test results of Example 6:

[0136] When the catalyst is applied to the electrocatalytic reduction of carbon dioxide, the test results of Example 6 show that its C 2+ The selectivity of the product can be maintained at over 60%, and the stability is good.

[0137] (4) Compare the test results of Example 6 and Comparative Example 1:

[0138] When catalysts are used in the electrocatalytic reduction of carbon dioxide, such as Figure 7 As shown, the C measured under the same current density is compared. 2+ The selective stability of the product, in Example 6, after a reaction of 120 h, C 2+ The selectivity of the product can be maintained above 60%, while in Comparative Example 1, the initial reaction, C 2+The product selectivity is around 43%, the reaction time is 17 hours, and the concentration is C. 2+ The selectivity of the product decreased rapidly after 12 hours, eventually reaching less than 20%; these results indicate that, compared to Comparative Example 1, the polyaniline modification in Example 6 significantly improved the C2O catalyst's selectivity. 2+ The product selectivity is significantly improved, which may be because the polyaniline coating on the Cu2O surface enhances the stability of positive copper, thereby increasing the coverage of the *CO intermediate and promoting carbon-carbon coupling. In addition, polyaniline modification can also greatly reduce the rate of corrosion of Cu2O catalyst by electrolyte and significantly improve its stability.

[0139] (4) Compare the test results of Example 6 and Comparative Examples 1-3:

[0140] When the catalyst was applied to the electrocatalytic reduction of carbon dioxide, the test results of Comparative Example 6 and Comparative Examples 1-3 showed that the elemental copper in Comparative Example 3 and the polyaniline-coated elemental copper in Comparative Example 2 had lower C values. 2+ The selectivity of the product was lower than that of the cuprous oxide catalyst in Comparative Example 1 and the Cu2O@PANI catalyst in Example 6, indicating that the C of the zero-valent copper catalyst is lower regardless of whether polyaniline modification is used. 2+ The product selectivity was significantly weaker than that of the Cu2O catalyst. Comparing Comparative Example 2 and Comparative Example 3, it was found that Comparative Example 2 had significantly better stability. This indicates that modification with polyaniline can greatly improve the stability of the zero-valent copper catalyst, but it also affects its C... 2+ The product selectivity was not improved.

[0141] (5) Compare the test results of Examples 1 and 4:

[0142] Comparing the test results of Examples 7-8 and Comparative Example 4, it can be seen that under acidic conditions, the PANI-coated Cu2O catalyst can significantly increase the C content in the electrocatalytic CO reduction reaction. 2+ The product selectivity promotes coupling and inhibits the hydrogen evolution reaction. Consistent with the stability trend of the carbon dioxide electrocatalytic reduction reaction, PANI coating can extend the stability of the carbon monoxide electrocatalytic reduction reaction from 3 hours to 25 hours. In summary, the PANI coating strategy improves the stability of the carbon monoxide electrocatalytic reduction reaction. 2+ The catalyst exhibits excellent product selectivity and enhanced stability under acidic conditions, making it widely applicable. It can be used for the electrocatalytic reduction of carbon monoxide and / or carbon dioxide to produce multi-carbon products.

[0143] Compared with the prior art, the present invention has the following beneficial effects:

[0144] 1. This invention uses Cu2O instead of elemental Cu as the catalyst active material. Coating the surface of Cu2O particles with polyaniline not only inhibits the hydrogen evolution reaction but also improves the stability of positive copper, thereby increasing the coverage of the *CO intermediate and promoting carbon-carbon coupling.

[0145] The results of the examples show that the Cu2O@PANI catalyst prepared according to the technical solution of the present invention can enable C 2+ The selectivity of the product is significantly improved.

[0146] When applied to the electroreduction of carbon dioxide to prepare multi-carbon products, at 500 mA·cm -2 At current density, C 2+ The product exhibits the highest Faraday efficiency, reaching 75.4%; when applied to the electroreduction of carbon monoxide to prepare multi-carbon products, it achieves high efficiency in the range of 50–1200 mA·cm⁻¹. -2 Within the current density range, C 2+ The Faraday efficiency of the products can all reach over 74.6% at 300 mA·cm⁻¹. -2 It reaches a maximum of 88.8% at current density.

[0147] 2. In this invention, the active material Cu2O is coated with polyaniline, which avoids the corrosion of the catalyst by the acidic electrolyte and ensures the good stability of the Cu2O@PANI catalyst. Furthermore, Cu2O particles synthesized by the solvothermal method are relatively large and not prone to agglomeration. However, by using an in-situ chemical oxidation method to coat the Cu2O surface with polyaniline, a more uniform coating layer is formed, which further improves the stability of the Cu2O@PANI catalyst.

[0148] 3. The copper-based catalyst prepared by this invention can be used to prepare multi-carbon products by electroreduction of carbon dioxide in an acidic system. When used as the cathode in a flow electrolytic cell in an acidic system, the acidic system avoids the salt precipitation problem caused by the alkaline system, thus greatly improving the utilization rate of carbon dioxide.

[0149] 4. The copper-based catalyst prepared by this invention can be used in the electroreduction of carbon dioxide to prepare multi-carbon products in an acidic system. When used as the cathode in a flowing electrolyzer, it can achieve a current of 200 mA·cm⁻¹. -2 Stable operation at current density for 120 hours, while C 2+ Selectivity was maintained at over 60%; lifespan was extended by approximately 10 times under the same conditions compared to similar previously reported research results.

[0150] The copper-based catalyst prepared by this invention is used in the electroreduction of carbon monoxide to prepare multi-carbon products in an acidic system. When used as the cathode in a flowing electrolyzer, it can achieve an efficiency of 300 mA·cm⁻¹. -2 Stable operation at current density for 25 hours, while C2+ The selectivity of the product remained above 80%, and its stability was significantly improved compared to Cu2O catalyst.

[0151] 5. The copper-based catalyst prepared in this invention is used in the electroreduction of carbon dioxide to prepare multi-carbon products in an acidic system. When used as the cathode in a flowing electrolyzer, it achieves a reaction rate of 5 mL·min⁻¹. -1 At a CO2 flow rate, using an acidic electrolyte with a pH of 3, the CO2 conversion rate can reach 40.5%. Through comparative experiments, the inventors found that using a neutral electrolyte with a pH of 7.3, the CO2 conversion rate is only 11.8% at the same CO2 flow rate; and using an alkaline electrolyte with a pH of 13.7, the CO2 conversion rate is only 9.47% at the same CO2 flow rate. This demonstrates that the acidic system significantly improves the utilization rate of carbon dioxide.

[0152] 6. The copper-based catalyst prepared by this invention is used as the cathode in a flow electrolyzer for the electroreduction of carbon dioxide to produce multi-carbon products in an acidic system. At a relatively low CO2 flow rate (5 mL·min⁻¹), it achieves optimal performance. -1 At pH 3, the acidic electrolyte can still maintain a high C0. 2+ Product selectivity (C 2+ Faraday efficiency can reach 68.4%.

[0153] In summary, this invention includes at least the following inventive mechanisms, inventive concepts, and technical effects:

[0154] The key features and greatest advantages of this invention are as follows: Polyaniline is directly coated onto the surface of Cu2O particles via in-situ chemical oxidation. The resulting polyaniline coating effectively protects the substrate catalyst (i.e., Cu2O particles), preventing corrosion and detachment of the copper catalyst in acidic electrolytes, thereby significantly improving catalyst stability. Furthermore, the polyaniline coating effectively stabilizes positive-valent copper, thereby increasing the coverage of key CO intermediates and effectively promoting coupling to form C. 2+ The product, which modifies the C content of the Cu2O catalyst, makes the polyaniline modification more effective. 2+ The product selectivity is significantly improved, and the prepared copper-based catalyst (i.e., Cu2O@PANI) has the advantages of high efficiency, high selectivity, and especially high stability.

[0155] It should be noted that the working principle and process of the electrocatalytic reduction of carbon dioxide and / or carbon monoxide to prepare multi-carbon products under acidic conditions are existing technologies, and the composition of each component of the flow electrolyzer, as well as its electroreduction reaction principle and process, are also existing technologies, and will not be elaborated here. This invention focuses on studying the applicability and effectiveness of this specific copper-based catalyst in the electrocatalytic reduction of carbon dioxide and / or carbon monoxide to prepare multi-carbon products under acidic conditions.

[0156] Furthermore, those skilled in the art should understand that although many problems exist in the prior art, each embodiment or technical solution of the present invention can be improved in only one or a few aspects, without necessarily solving all the technical problems listed in the prior art or the background art simultaneously. Those skilled in the art should understand that any content not mentioned in a claim should not be construed as a limitation on that claim.

[0157] Although this document frequently uses terms such as copper-containing compounds and solvothermal methods, the possibility of using other terms is not excluded. These terms are used merely for the convenience of describing and explaining the essence of the invention; interpreting them as any additional limitation would contradict the spirit of the invention. The terms "first," "second," etc. (if present) in the specification, claims, and accompanying drawings of the embodiments of the invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0158] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a copper-based catalyst, characterized in that, Includes the following steps: The copper-containing compound is dissolved in the first solvent to prepare solution A; After adding a reducing agent to solution A and stirring for 0.5–1.5 h, the solution is sealed and heated to a system temperature of 120 °C–200 °C for 1–20 h to obtain a suspension B containing Cu₂O cores; the molar ratio of Cu element to the reducing agent in the copper-containing compound is 1:(0.05–5). The suspension containing Cu2O cores was subjected to impurity removal and solid-liquid separation treatment to obtain Cu2O particles; The Cu2O particles were added to a second solvent to prepare suspension C; Aniline was added to the suspension C and stirred for 0.5–1.5 h, followed by the addition of ammonium persulfate for a polymerization reaction of 2–10 h to obtain a suspension containing a Cu2O@PANI core-shell structure; wherein the polymerization reaction temperature was controlled at 0–25 °C; the molar ratio of aniline to Cu2O particles in the suspension C was (0.1–0.6):1; the molar ratio of ammonium persulfate to Cu2O particles in the suspension C was (0.05–5):1; and the molar ratio of aniline to ammonium persulfate was (0.2–5):

1. The suspension containing the Cu2O@PANI core-shell structure was subjected to impurity removal and solid-liquid separation treatment to obtain the polyaniline-coated Cu2O catalyst. The copper-containing compound includes at least one of copper acetate, copper sulfate, copper nitrate, copper halide, and copper acetylacetonate; the first solvent includes at least one of ethanol, methanol, n-propanol, isopropanol, and water; and the mass percentage concentration of the copper-containing compound in solution A is 0.5% to 15%.

2. The method for preparing the copper-based catalyst according to claim 1, characterized in that: The reducing agent includes at least one of glucose, ascorbic acid, sodium citrate, and hydrazine hydrate.

3. The method for preparing the copper-based catalyst according to any one of claims 1 to 2, characterized in that: The second solvent is water; The mass ratio of Cu2O particles to the second solvent is (0.0005~0.005):

1.

4. A copper-based catalyst, characterized in that: It is prepared by the preparation method described in any one of claims 1 to 3.

5. An application of a copper-based catalyst, characterized in that: The copper-based catalyst is used to electroreduce carbon dioxide and / or carbon monoxide in an acidic system to prepare multi-carbon products, and the copper-based catalyst is used as the cathode in a flow electrolyzer. The copper-based catalyst is prepared by the preparation method described in any one of claims 1 to 3.

6. The application of the copper-based catalyst according to claim 5, characterized in that: Electroreduction reactions are carried out in a flowing electrolytic cell by passing gas into the cathode and applying a negative potential or negative current to electrolyze the product, thus producing a multi-carbon product. The gas is carbon dioxide and / or carbon monoxide, the cathode is the copper-based catalyst, the anode is at least one of iridium dioxide, titanium mesh, and titanium foam, and the saturated Ag / AgCl electrode is used as a reference electrode.

7. The application of the copper-based catalyst according to claim 6, characterized in that: In the electroreduction reaction of a flowing electrolytic cell, the flow rate of the gas is 1–100 mL·min. -1 ; Electrolytes include solutions of acids, solutions of salts, or mixed solutions of acids and salts. The concentration of the electrolyte is 0.01–10 mol·L⁻¹. -1 pH value less than 7; negative potential of -0.2V to -1.5V vs. RHE; negative current density of 50 to 2000 mA·cm⁻¹ -2 ; The multicarbon product includes at least one of ethylene, ethanol, acetic acid, and n-propanol.

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