Modification method of copper catalyst and application of copper catalyst in carbon dioxide electroreduction reaction

Abstract

The invention discloses a modification method of a copper catalyst and application of the copper catalyst in a carbon dioxide electroreduction reaction, and belongs to the technical field of metal catalysts, and the modification method specifically comprises the following steps: placing copper powder in air until a layer of cuprous oxide is oxidized on the surface, adding into a hydrogen peroxide aqueous solution, stirring for 0.5-3 hours, and filtering; and carrying out multiple centrifugal washing treatment and vacuum drying to obtain the modified copper catalyst. According to the method, the surfaces of the copper particles are subjected to oxidation treatment through hydrogen peroxide, the morphology and composition of the surfaces of the copper particles are changed, and the copper particles are applied to the carbon dioxide electroreduction reaction, so that the electrocatalytic reduction efficiency of multi-carbon products, especially the electrocatalytic reduction efficiency of the multi-carbon products ethanol and ethylene, is improved; the Faraday efficiency of 76% or above on a multi-carbon product is shown in a commercial gas diffusion type flowing electrolytic tank, the modification method is efficient, the technology is mild, the process is simple, green and environment-friendly are achieved, macro preparation is easy, and the method is suitable for wide chemical production.

Description

Technical Field

[0001] The invention belongs to the technical field of metal catalysts, and in particular relates to a method for modifying a copper catalyst and an application of the copper catalyst in a carbon dioxide electroreduction reaction. Background Art

[0002] Excessive carbon dioxide emissions caused by human production and life have caused a series of environmental problems such as the greenhouse effect. It is urgent to develop efficient carbon dioxide utilization technology. Among them, as sustainable energy power generation technology becomes more mature, clean electricity-driven carbon dioxide electroreduction reactions have gradually attracted attention. Through electric drive, carbon dioxide is converted into high-value-added chemicals such as formic acid, carbon monoxide, ethylene, and ethanol. While helping to increase the value of carbon dioxide, it also realizes the effective consumption of clean electricity and alleviates energy waste such as "abandoning wind" and "abandoning light".

[0003] Among the many products of carbon dioxide reduction reaction, the research on single-carbon products is relatively mature, and the selectivity of carbon monoxide and formic acid that have been studied is close to 100%. Compared with single-carbon products, multi-carbon products often have higher volume energy density and economic value. For example, the calorific value of ethylene is 54.2MJ m -3 , is carbon monoxide (11.5 MJ m -3 ) is nearly five times that of formic acid; the market price of ethanol (5,675 yuan / ton) is twice that of formic acid (2,775 yuan / ton). Multi-carbon molecules can also be used as important raw materials for the synthesis of chemical products such as long-chain hydrocarbon fuels and oxygen-containing compounds, and are widely used in chemical production. However, due to the large number of transferred electrons and complex reaction pathways of multi-carbon products, their preparation efficiency is not ideal.

[0004] Due to its moderate adsorption energy for reaction coupling intermediates, copper has become a commonly used catalytic material for catalyzing the electroreduction of carbon dioxide to produce multi-carbon products. However, the products obtained by copper catalysis are complex, and the selectivity for multi-carbon products needs to be further optimized. Therefore, the development of efficient copper catalysts for catalyzing the electroreduction of carbon dioxide to produce multi-carbon products has become one of the research hotspots in this field. Summary of the invention

[0005] In view of the problem that existing copper catalysts produce complex products in the carbon dioxide electroreduction reaction, the present invention provides a method for modifying a copper catalyst and its application in the carbon dioxide electroreduction reaction. The surface of copper particles is oxidized by hydrogen peroxide, which significantly improves the activity and selectivity of copper-based materials in the electrocatalytic reduction of carbon dioxide to multi-carbon products. In addition, the synthesis method is green, mild, simple and fast, and is suitable for large-scale production and application.

[0006] The technical solution adopted by the present invention is as follows:

[0007] A method for modifying a copper catalyst comprises the following steps:

[0008] Step 1: Place copper powder in air to oxidize a layer of cuprous oxide on the surface of the copper particles;

[0009] Step 2, adding the copper powder treated in step 1 into a hydrogen peroxide solution, stirring for 0.5 to 3 hours to obtain a suspension; wherein the mass volume ratio of the copper powder to the hydrogen peroxide solution is 0.01 to 0.25 mg / ml;

[0010] Step 3: The suspension is subjected to multiple centrifugal washing treatments and vacuum drying to obtain a modified copper catalyst.

[0011] Furthermore, the size of the copper particles is 0.5 to 2 microns.

[0012] Furthermore, the modified copper catalyst is a copper particle with a scaly surface, and the components of the scaly structure include cuprous oxide and cupric oxide.

[0013] Furthermore, in step 2, the mass fraction of the aqueous hydrogen peroxide solution is 10% to 30%.

[0014] Furthermore, the stirring temperature in step 2 is room temperature.

[0015] Furthermore, the stirring rate in step 2 is 500 to 2000 revolutions per minute.

[0016] Furthermore, the centrifugal speed in step 3 is 1000 to 3000 revolutions per minute.

[0017] Furthermore, the washing solvent used in step 3 is one or more of deionized water, isopropanol, etc.

[0018] Furthermore, the volume of the washing solvent used in step 3 is 50 to 100 ml.

[0019] Furthermore, the number of centrifugal washing in step 3 is 2 to 4 times.

[0020] Furthermore, the vacuum drying temperature in step 3 is 20 to 40 degrees Celsius.

[0021] Furthermore, the vacuum drying time in step 3 is 3 to 10 hours.

[0022] The present invention also provides the use of a modified copper catalyst obtained by any modification method of the above technical scheme in a carbon dioxide electroreduction reaction.

[0023] A carbon dioxide electric reduction reaction device adopts the modified copper catalyst to prepare catalyst ink, which is sprayed on a gas diffusion layer and used as a working electrode for carbon dioxide electric reduction reaction.

[0024] Furthermore, the concentration of the catalyst ink is 5 to 20 mg / ml.

[0025] Furthermore, the solvent of the catalyst ink is one or more of isopropyl alcohol, water and the like.

[0026] Furthermore, the spraying amount of the catalyst ink is 0.2 to 2 mg of the modified copper catalyst per square centimeter of the gas diffusion layer.

[0027] Furthermore, the carbon dioxide electroreduction reaction device is implemented based on a gas diffusion type flow electrolytic cell.

[0028] Furthermore, the cathode electrolyte used in the carbon dioxide electric reduction reaction device includes one or more of potassium bicarbonate, potassium hydroxide, sodium bicarbonate, sodium hydroxide, etc., and the concentration of the cathode electrolyte is 0.1 to 3 mol per liter.

[0029] Furthermore, the anode electrolyte used in the carbon dioxide electric reduction reaction device includes one or more of potassium bicarbonate, potassium hydroxide, sodium bicarbonate, sodium hydroxide, perchloric acid, sulfuric acid, etc., and the concentration of the anode electrolyte is 0.05 to 2 mol per liter.

[0030] Furthermore, the ion exchange membrane used in the carbon dioxide electric reduction reaction device is a proton exchange membrane or a bipolar membrane.

[0031] Furthermore, the carbon dioxide electroreduction reaction is carried out in a constant current mode or a constant voltage mode at normal pressure. When electrolysis is carried out in a constant current mode, the current density range is -50 to -600 milliamperes per square centimeter; when electrolysis is carried out in a constant voltage mode, the voltage range is -1.0 to -3.0 volts.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] 1. The present invention proposes a copper catalyst modification method, which uses hydrogen peroxide to oxidize the surface of copper particles to change the morphology and composition of the copper particles, so that the copper catalyst can be applied to the carbon dioxide electroreduction reaction to help improve the electrocatalytic reduction efficiency of multi-carbon products, especially the electrocatalytic reduction efficiency of ethanol and ethylene. Ethanol and ethylene not only have higher energy density and economic value, but are also often used as basic organic raw materials for the production of chemicals such as polyethylene, vinyl chloride, styrene, ethylene oxide, acetic acid, acetaldehyde, ethylamine, ethyl acetate, etc., and are widely used in chemical production. Therefore, improving the production efficiency of ethanol and ethylene is of great significance;

[0034] 2. Specifically, the modified copper catalyst obtained by the present invention exhibits a Faraday efficiency (selectivity) of more than 76% for multi-carbon products in a commercial gas diffusion flow electrolytic cell, the maximum effective current density of multi-carbon products reaches -376 milliamperes per square centimeter, and the selectivity ratio of multi-carbon products to single-carbon products reaches 4.4, which is 3.3 times that of the copper catalyst before modification;

[0035] 3. The modification method of the present invention is efficient, mild in process, simple in procedure, green and environmentally friendly, and easy to prepare in large quantities, providing an effective strategy for optimizing copper catalysts for the electrocatalytic carbon dioxide reduction reaction to produce multi-carbon products. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 is a scanning electron microscope photograph of the copper powder (i.e., commercial micron copper powder) after being treated in step 1 in Example 1 of the present invention;

[0037] Figure 2 This is a scanning electron microscope photograph of the modified copper catalyst (i.e., flaky microsphere copper catalyst) obtained in Example 1 of the present invention;

[0038] Figure 3 The X-ray diffraction spectra of the flaky microsphere copper catalyst and the commercial micron copper powder obtained in Example 1 of the present invention;

[0039] Figure 4 The X-ray photoelectron spectra of the flaky microsphere copper catalyst and the commercial micron copper powder obtained in Example 1 of the present invention are shown;

[0040] Figure 5 The product distribution and Faraday efficiency of the carbon dioxide electroreduction reaction catalyzed by the commercial micron copper powder in Example 1 of the present invention in a commercial gas diffusion flow electrolytic cell;

[0041] Figure 6 The product distribution and Faraday efficiency of the electroreduction reaction of carbon dioxide catalyzed by the flaky microsphere copper catalyst obtained in Example 1 of the present invention in a commercial gas diffusion flow electrolytic cell;

[0042] Figure 7 The Faraday efficiency of the multi-carbon product of the carbon dioxide electroreduction reaction catalyzed by the flaky microsphere copper catalyst obtained in Example 1 of the present invention and the commercial micron copper powder in a commercial gas diffusion flow electrolytic cell;

[0043] Figure 8 The product distribution and Faraday efficiency of the electroreduction reaction of carbon dioxide catalyzed by the flaky microsphere copper catalyst obtained in Example 2 of the present invention in a commercial gas diffusion flow electrolytic cell;

[0044] Fig. 9The product distribution and Faraday efficiency of the flaky copper microsphere catalyst obtained in Example 3 of the present invention in the electroreduction reaction of carbon dioxide catalyzed in a commercial gas diffusion flow electrolytic cell. DETAILED DESCRIPTION

[0045] In order to further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples, but it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the invention.

[0046] All raw materials of the present invention have no particular limitation on their sources, and can be purchased from the market or prepared according to conventional methods known to those skilled in the art.

[0047] There is no particular limitation on the purity of all raw materials in the present invention. The present invention preferably adopts analytically pure materials or materials with conventional purity requirements in the field of atomic layer deposition.

[0048] All raw materials and process steps of the present invention, their brands or abbreviations are conventional brands or abbreviations in the art, and each brand or abbreviation is clear and definite in the field of its related use. Those skilled in the art can purchase them from the market or prepare them by conventional methods, or implement them with corresponding equipment according to the brands, abbreviations and corresponding uses.

[0049] The present invention provides a method for modifying a copper catalyst, comprising the following steps:

[0050] Step 1: Place copper powder in air to oxidize a layer of cuprous oxide on the surface of the copper particles;

[0051] Step 2, adding the copper powder treated in step 1 into a hydrogen peroxide solution, stirring for 0.5 to 3 hours to obtain a suspension; wherein the mass volume ratio of the copper powder to the hydrogen peroxide solution is 0.01 to 0.25 mg / ml;

[0052] Step 3: The suspension is subjected to multiple centrifugal washing treatments and vacuum drying to obtain a modified copper catalyst.

[0053] Furthermore, the size of the copper particles is 0.5 to 2 microns, preferably 0.5 to 1 micron.

[0054] Furthermore, the modified copper catalyst is a copper particle with a scaly surface, and the components of the scaly structure include cuprous oxide and cupric oxide.

[0055] Furthermore, in step 2, the mass volume ratio of copper powder to aqueous hydrogen peroxide solution is preferably 0.2 to 0.25 mg / ml.

[0056] Furthermore, in step 2, the mass fraction of the aqueous hydrogen peroxide solution is 10% to 30%, preferably 25% to 30%.

[0057] Furthermore, the stirring time in step 2 is preferably 2.5 to 3 hours.

[0058] Furthermore, the stirring temperature in step 2 is room temperature.

[0059] Furthermore, the stirring rate in step 2 is 500 to 2000 revolutions per minute, preferably 800 to 1200 revolutions per minute.

[0060] Furthermore, the centrifugal speed in step 3 is 1000 to 3000 rpm, preferably 1500 to 2000 rpm.

[0061] Furthermore, the washing solvent used in step 3 is one or more of deionized water, isopropanol, etc., preferably deionized water.

[0062] Furthermore, the volume of the washing solvent used in step 3 is 50 to 100 ml, preferably 80 to 100 ml.

[0063] Furthermore, the number of centrifugal washing in step 3 is 2 to 4 times, preferably 3 times.

[0064] Furthermore, the vacuum drying temperature in step 3 is 20 to 40 degrees Celsius, preferably 20 to 30 degrees Celsius.

[0065] Furthermore, the vacuum drying time in step 3 is 3 to 10 hours, preferably 8 to 10 hours.

[0066] The present invention also provides the use of a modified copper catalyst obtained by any modification method of the above technical scheme in a carbon dioxide electroreduction reaction.

[0067] A carbon dioxide electric reduction reaction device adopts the modified copper catalyst to prepare catalyst ink, which is sprayed on a gas diffusion layer and used as a working electrode for carbon dioxide electric reduction reaction.

[0068] Furthermore, the concentration of the catalyst ink is 5 to 20 mg / ml, preferably 8 to 12 mg / ml.

[0069] Furthermore, the solvent of the catalyst ink is one or more of isopropyl alcohol, water, etc., preferably isopropyl alcohol.

[0070] Furthermore, the spraying amount of the catalyst ink is 0.2-2 mg of modified copper catalyst per square centimeter of gas diffusion layer, preferably 0.5-1.5 mg of catalyst per square centimeter.

[0071] Furthermore, the carbon dioxide electroreduction reaction device is implemented based on a gas diffusion type flow electrolytic cell.

[0072] Furthermore, the cathode electrolyte used in the carbon dioxide electric reduction reaction device includes one or more of potassium bicarbonate, potassium hydroxide, sodium bicarbonate, sodium hydroxide, etc., preferably potassium bicarbonate or potassium hydroxide; the concentration of the cathode electrolyte is 0.1 to 3 mol per liter, preferably 0.5 to 1 mol per liter.

[0073] Furthermore, the anode electrolyte used in the carbon dioxide electric reduction reaction device includes one or more of potassium bicarbonate, potassium hydroxide, sodium bicarbonate, sodium hydroxide, perchloric acid, sulfuric acid, etc., preferably potassium hydroxide; the concentration of the anode electrolyte is 0.05 to 2 mol per liter, preferably 0.5 to 1.5 mol per liter.

[0074] Furthermore, the ion exchange membrane used in the carbon dioxide electric reduction reaction device is a proton exchange membrane or a bipolar membrane, etc., preferably a proton exchange membrane.

[0075] Furthermore, the carbon dioxide electroreduction reaction is carried out in a constant current mode or a constant voltage mode at normal pressure. When electrolysis is carried out in a constant current mode, the current density range is -50 to -600 milliamperes per square centimeter, preferably -300 to -500 milliamperes per square centimeter; when electrolysis is carried out in a constant voltage mode, the voltage range is -1.0 to -3.0 volts, preferably -1.7 to -2.0 volts.

[0076] In order to further illustrate the present invention, a modification method of a copper catalyst provided by the present invention and its application in the carbon dioxide electro-reduction reaction are described in detail below in combination with examples. However, it should be understood that these examples are implemented on the premise of the technical scheme of the present invention, and detailed implementation methods and specific operating processes are given only to further illustrate the features and advantages of the present invention, rather than to limit the claims of the present invention, and the protection scope of the present invention is not limited to the following examples.

[0077] Example 1

[0078] This embodiment provides a method for modifying a copper catalyst, which specifically comprises the following steps:

[0079] Step 1, placing copper powder with a particle size of 1 micron in the air to oxidize a layer of cuprous oxide on the surface of the copper particles, thereby obtaining commercial micron copper powder;

[0080] Step 2, adding the commercial micron copper powder obtained in step 1 into a 30% by mass aqueous solution of hydrogen peroxide, stirring at a speed of 1000 revolutions per minute at room temperature for 3 hours to obtain a suspension; wherein the mass volume ratio of the copper powder to the hydrogen peroxide aqueous solution is 0.25 mg / ml;

[0081] Step 3, the suspension was centrifuged and washed three times, specifically at a speed of 2000 revolutions per minute, and the precipitate was washed with 100 ml of deionized water and redispersed to obtain a precipitate;

[0082] Step 4: Place the precipitate in a vacuum drying oven at 25 degrees Celsius for 10 hours to dry it to obtain a modified copper catalyst, namely, a flaky microsphere copper catalyst.

[0083] The structure of the flaky microsphere copper catalyst obtained in this example is characterized below.

[0084] Figure 1 This is a scanning electron microscope photograph of the commercial micron copper powder in this embodiment. It can be seen that the copper particles are spherical and have a relatively flat surface before being oxidized by the hydrogen peroxide aqueous solution.

[0085] Figure 2 This is a scanning electron microscope photograph of the flaky microsphere copper catalyst obtained in this example. It can be seen that after the spherical copper particles are oxidized by aqueous hydrogen peroxide, their surfaces are flaky.

[0086] Figure 3 The X-ray diffraction spectra of the flaky microsphere copper catalyst and the commercial micron copper powder obtained in this example can be seen from the figure that after the oxidation treatment with aqueous hydrogen peroxide, the peak corresponding to cuprous oxide on the surface of the commercial micron copper powder weakens, and the peak corresponding to cupric oxide appears, indicating that part of the cuprous oxide on the surface of the commercial micron copper powder is oxidized to cupric oxide.

[0087] Figure 4 The X-ray photoelectron spectra of the flaky microsphere copper catalyst and the commercial micron copper powder obtained in this example are shown in FIG. 1 . As can be seen from the figure, after the surface treatment with hydrogen peroxide aqueous solution, the divalent copper satellite peak (i.e., the signal corresponding to copper oxide) on the surface of the copper catalyst is significantly enhanced, which is consistent with the Figure 3 The conclusion is consistent with that of the X-ray diffraction spectrum.

[0088] This embodiment also proposes a carbon dioxide electroreduction reaction device, which uses the flaky microsphere copper catalyst obtained in this embodiment to prepare catalyst ink, which is sprayed onto a gas diffusion layer and used as a working electrode for carbon dioxide electroreduction reaction.

[0089] Next, based on the carbon dioxide electroreduction reaction device, the catalytic performance of the flaky microsphere copper catalyst obtained in this example was tested for the carbon dioxide electroreduction reaction.

[0090] The flaky microsphere copper catalyst obtained in this embodiment is dispersed with isopropanol to prepare a catalyst ink with a concentration of 5 to 20 mg per milliliter. The catalyst ink is evenly sprayed on the gas diffusion layer with a loading amount of 1 mg per square centimeter of flaky microsphere copper catalyst. The flaky microsphere copper catalyst loaded on the gas diffusion layer is used as a working electrode, nickel foam is used as a counter electrode, a silver / silver chloride electrode (containing a saturated potassium chloride solution) is used as a reference electrode, a proton exchange membrane is used as an ion exchange membrane, a 0.5 mol per liter potassium bicarbonate solution is used as a cathode electrolyte, and a 1 mol per liter potassium sulfate solution is used as an anolyte. A carbon dioxide electroreduction reaction device is obtained based on a commercial gas diffusion type flow electrolytic cell, and a carbon dioxide electroreduction performance test is performed. This embodiment is tested using a constant current method, and the added cathode current density range is -50 to -600 mA per square centimeter. The gaseous products obtained from the carbon dioxide electroreduction reaction were carried to the gas chromatography by argon carrier gas, and the liquid products were detected by ion chromatography. The coulomb amount corresponding to the product concentration was calculated, and the catalytic selectivity, activity and other data were obtained based on the total coulomb amount recorded by the electrochemical workstation.

[0091] Figure 5 The product distribution and Faraday efficiency of the carbon dioxide electroreduction reaction catalyzed by the commercial micron copper powder obtained in step 1 in a commercial gas diffusion flow electrolytic cell are shown. It can be seen that under different test cathode currents, the main products of the carbon dioxide reduction reaction of the commercial micron copper powder catalyst are carbon monoxide, hydrogen, ethylene, ethanol, etc., among which multi-carbon products such as ethylene and ethanol account for a relatively low proportion, and the Faraday efficiency (selectivity) of multi-carbon products is only 41% at a current density of 400 mA per square centimeter.

[0092] Figure 6 The product distribution and Faraday efficiency of the carbon dioxide electroreduction reaction catalyzed by the flaky microsphere copper catalyst obtained in this embodiment in a commercial gas diffusion type flow electrolyzer are shown. It can be seen that under different test cathode currents, the main products of the carbon dioxide reduction reaction of the flaky microsphere copper catalyst are carbon monoxide, ethylene, ethanol, etc., among which multi-carbon products such as ethylene and ethanol account for a relatively high proportion. It can be seen that the multi-carbon product Faraday efficiency (selectivity) of the flaky microsphere copper catalyst can reach more than 76% at a current density of 400 mA per square centimeter, which is significantly higher than the multi-carbon product selectivity of commercial micron copper powder.

[0093] Figure 7 The Faraday efficiency of the multi-carbon products of the carbon dioxide electroreduction reaction catalyzed by the flaky microsphere copper catalyst obtained in this example is compared with that of commercial micron copper powder in a commercial gas diffusion flow electrolytic cell. It can be seen that the maximum effective current density of the multi-carbon products of the flaky microsphere copper catalyst reaches -376 milliamperes per square centimeter, indicating that the oxidation treatment with aqueous hydrogen peroxide solution can significantly improve the selectivity of the copper catalyst for multi-carbon products in the carbon dioxide electroreduction reaction.

[0094] Example 2

[0095] This embodiment provides a method for modifying a copper catalyst. The process is different from that of Embodiment 1, except that the normal temperature stirring treatment time of Step 2 is adjusted to 1 hour; the other steps are exactly the same.

[0096] The flaky microsphere copper catalyst obtained in this example is applied to the carbon dioxide electroreduction reaction, specifically used as a working electrode of a commercial gas diffusion flow electrolytic cell.

[0097] Figure 8 The product distribution and Faraday efficiency of the carbon dioxide electroreduction reaction catalyzed by the flaky microsphere copper catalyst obtained in this embodiment in a commercial gas diffusion type flow electrolyzer are shown. It can be seen that under different test cathode currents, the main products of the carbon dioxide reduction reaction of the flaky microsphere copper catalyst are carbon monoxide, ethylene, ethanol, etc., among which multi-carbon products such as ethylene and ethanol account for a relatively high proportion. It can be seen that the multi-carbon product Faraday efficiency (selectivity) of the flaky microsphere copper catalyst reaches more than 76% at a current density of 400 mA per square centimeter, which is significantly higher than the multi-carbon product selectivity of commercial micron copper powder.

[0098] Example 3

[0099] This embodiment provides a method for modifying a copper catalyst. The process is different from that of Embodiment 1, except that the normal temperature stirring treatment time of Step 2 is adjusted to 0.5 hours; the other steps are exactly the same.

[0100] The flaky microsphere copper catalyst obtained in this example is applied to the carbon dioxide electroreduction reaction, specifically used as a working electrode of a commercial gas diffusion flow electrolytic cell.

[0101] Fig. 9 The product distribution and Faraday efficiency of the carbon dioxide electroreduction reaction catalyzed by the flaky microsphere copper catalyst obtained in this example in a commercial gas diffusion flow electrolyzer are shown. It can be seen that under different test cathode currents, the main products of the carbon dioxide reduction reaction of the flaky microsphere copper catalyst are carbon monoxide, ethylene, ethanol, etc., among which ethylene, ethanol and other multi-carbon products account for a high proportion. It can be seen that the multi-carbon product Faraday efficiency (selectivity) of the flaky microsphere copper catalyst reaches more than 67% at a current density of 400 mA per square centimeter, which is significantly higher than the multi-carbon product selectivity of commercial micron copper powder. .

[0102] Example 4

[0103] This embodiment provides a method for modifying a copper catalyst. The process is different from that of Example 1, except that the mass volume ratio of copper powder to hydrogen peroxide aqueous solution in step 2 is adjusted to 0.2 mg / ml; the other steps are exactly the same.

[0104] The flaky microsphere copper catalyst obtained in this example is applied to the carbon dioxide electroreduction reaction, specifically used as a working electrode of a commercial gas diffusion flow electrolytic cell.

[0105] Example 5

[0106] This embodiment provides a method for modifying a copper catalyst. The process is different from that of Example 1, except that the mass volume ratio of copper powder to aqueous hydrogen peroxide solution in step 2 is adjusted to 0.01 mg / ml; the other steps are exactly the same.

[0107] The flaky microsphere copper catalyst obtained in this example is applied to the carbon dioxide electroreduction reaction, specifically used as a working electrode of a commercial gas diffusion flow electrolytic cell.

[0108] Example 6

[0109] This embodiment provides a method for modifying a copper catalyst. The process is different from that of Embodiment 1 in that the mass fraction of the aqueous hydrogen peroxide solution in step 2 is adjusted to 10%; the other steps are exactly the same.

[0110] The flaky microsphere copper catalyst obtained in this example is applied to the carbon dioxide electroreduction reaction, specifically used as a working electrode of a commercial gas diffusion flow electrolytic cell.

[0111] The above embodiments only illustrate the principles and advantages of the present invention, and are not intended to limit the present invention. They are only intended to help understand the principles of the present invention. The protection scope of the present invention is not limited to the above configurations and embodiments. Those skilled in the art can make various other specific modifications and combinations based on the disclosed technology without departing from the essence of the present invention, but they are still within the protection scope of the present invention.

Claims

1. A method for modifying a copper catalyst, characterized in that: The following steps are involved: Step 1: Place copper powder in air to oxidize a layer of cuprous oxide on the surface of the copper particles; Step 2, adding the copper powder treated in step 1 into a hydrogen peroxide solution, stirring for 0.5 to 3 hours to obtain a suspension; wherein the mass volume ratio of the copper powder to the hydrogen peroxide solution is 0.01 to 0.25 mg / ml; Step 3: The suspension is subjected to multiple centrifugal washing treatments and vacuum drying to obtain a modified copper catalyst.

2. The method for modifying a copper catalyst according to claim 1, characterized in that: The size of the copper particles is 0.5 to 2 microns.

3. The method for modifying a copper catalyst according to claim 1, characterized in that: The mass fraction of the aqueous hydrogen peroxide solution in step 2 is 10% to 30%.

4. The method for modifying a copper catalyst according to claim 1, characterized in that: The stirring temperature in step 2 is room temperature, and the stirring speed is 500 to 2000 revolutions per minute.

5. The method for modifying a copper catalyst according to claim 1, characterized in that: The centrifugal speed in step 3 is 1000 to 3000 revolutions per minute, the washing solvent used for washing is one or more of deionized water and isopropanol, and the number of centrifugal washing is 2 to 4 times.

6. The method for modifying a copper catalyst according to claim 1, characterized in that: The vacuum drying temperature in step 3 is 20 to 40 degrees Celsius and the time is 3 to 10 hours.

7. Use of the modified copper catalyst obtained by the modification method according to any one of claims 1 to 6 in the electro-reduction reaction of carbon dioxide.

8. A carbon dioxide electroreduction reaction device, characterized in that: The modified copper catalyst obtained by the modification method according to any one of claims 1 to 6 is prepared into catalyst ink, which is sprayed onto a gas diffusion layer and used as a working electrode.

9. The carbon dioxide electric reduction reaction device according to claim 8, characterized in that: The carbon dioxide electroreduction reaction device is implemented based on a gas diffusion type flow electrolytic cell.

10. The carbon dioxide electric reduction reaction device according to claim 8, characterized in that: The concentration of the catalyst ink is 5-20 mg / ml, and the spraying amount is 0.2-2 mg of modified copper catalyst per square centimeter of gas diffusion layer.

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