Copper-silver double-monatomic electro-catalytic material as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of electrochemical energy materials, and particularly discloses a copper-silver double-monatomic electro-catalysis material and a preparation method and application thereof. The preparation method comprises the following steps: coating dopamine hydrochloride with silicon dioxide as a template to provide a nitrogen source and a carbon source, and carbonizing and etching to obtain the porous nitrogen-doped hollow carbon spheres with high specific surface area, thereby obtaining high carbon dioxide adsorption activity and high carbon monoxide desorption activity. And then through uniform loading of the copper-silver double monoatoms on the porous nitrogen-doped hollow carbon spheres and the electron action between doped nitrogen, the hydrogen evolution reaction is reduced, and the selectivity of CO2RR of the copper-silver double monoatom loaded porous nitrogen-doped hollow carbon sphere electrocatalytic material is greatly improved. The copper-silver double-monatomic electrocatalytic material provided by the invention is used for electrocatalytic reduction of carbon dioxide, and the synthesis process is simple in procedure, convenient to operate, short in reaction time, reliable in repeatability, low in production cost and very suitable for large-scale industrial production.

Description

Technical Field

[0001] The present invention relates to the technical field of electrochemical energy materials, and in particular to a copper-silver double single-atom electrocatalytic material and a preparation method and application thereof. Background Art

[0002] The electrocatalytic reduction of carbon dioxide (CO2RR) is considered a promising route to convert carbon dioxide into value-added chemicals through electrochemical processes. Although the reduction of carbon dioxide to C1 products has made significant progress in industrial applications in recent years, the formation of C1 products with higher energy density and higher commercial value is still a hot topic. n , n≥2(C2 + )Multi-carbon molecules are more ideal, but still challenging.

[0003] Copper-based materials are widely used in CO2RR to produce C2 due to their special CC coupling ability. + *CO and CO-related intermediates (such as *OCCO) were confirmed to form C2 + The increase in *CO surface coverage can further improve CC coupling. However, the selectivity and adsorption strength of copper-based materials for reaction intermediates such as *CO and *OCCO are still limited. It has been reported that tandem catalysts using copper-based materials in conjunction with CO generation catalysts such as Ag, Au or Zn can easily form a high coverage of surface *CO intermediates, and then transfer *CO to Cu active sites through overflow. This ingenious design divides the reaction into different steps through local multiple catalytic sites in the CO generation catalyst / Cu-based material. As a tandem catalyst, it is very useful for converting CO2RR to C2 + The products are attractive. Therefore, how to design and regulate different structural units in tandem catalysts to achieve multifunctional synergistic optimization including C / C coupling, CO generation and spillover, compared with single-phase catalysts, is an urgent problem to be solved. Summary of the invention

[0004] The purpose of the present invention is to provide a copper-silver double single atom electrocatalytic material and its preparation method and application in view of the above-mentioned deficiencies of the prior art, prepare porous nitrogen-doped hollow carbon spheres by a silica template method, and further prepare copper-silver double single atoms loaded on porous nitrogen-doped hollow carbon sphere electrocatalytic materials by liquid nitrogen freezing and thermal decomposition, thereby improving the carbon dioxide adsorption activity. Through the tandem action of Cu and Ag, the coverage of surface *CO intermediates is promoted, and then *CO is transferred to Cu active sites by overflow action, thereby promoting CC coupling, greatly improving the CO2RR production of C2 by copper-silver double single atoms loaded on porous nitrogen-doped hollow carbon sphere electrocatalytic materials. + Product selectivity.

[0005] The first aspect of the present invention is to provide a method for preparing a copper-silver double single-atom electrocatalytic material, comprising the following steps:

[0006] S1. Preparation of silica spheres wrapped with dopamine hydrochloride: a certain amount of deionized water, ethanol, tetraethyl orthosilicate and ammonia water are mixed and stirred, and then dopamine hydrochloride solution is added and stirred, and carbonization treatment is performed to obtain silica spheres wrapped with dopamine hydrochloride;

[0007] S2, preparing nitrogen-coated silica spheres: calcining the dopamine hydrochloride-coated silica spheres obtained in step S1 at high temperature to obtain nitrogen-coated silica spheres;

[0008] S3, preparing nitrogen-doped hollow carbon spheres: adding the nitrogen-doped carbon-coated silica spheres obtained in step S2 into a hydrofluoric acid solution, stirring, centrifugally washing, and drying to obtain nitrogen-doped hollow carbon spheres;

[0009] S4. Preparation of copper-silver double single-atom electrocatalytic material loaded on porous nitrogen-doped hollow carbon spheres: after uniformly dispersing the nitrogen-doped hollow carbon spheres obtained in step S3 in deionized water, adding copper salt and silver salt and stirring, freezing, drying and calcining to obtain the copper-silver double single-atom electrocatalytic material loaded on nitrogen-doped hollow carbon spheres.

[0010] Furthermore, in step S1, the stirring time of deionized water, ethanol, tetraethyl orthosilicate and ammonia water is 20 to 40 minutes.

[0011] Furthermore, in step S2, after adding the dopamine hydrochloride solution, the stirring time is 24 to 48 hours, the high temperature calcination temperature is 700 to 1000° C., and the calcination time is 3 to 3.5 hours.

[0012] Further, in step S3, the mass ratio of the nitrogen-doped carbon-coated silica spheres to the hydrofluoric acid is 1:1000.

[0013] Furthermore, in step S3, the concentration of the hydrofluoric acid solution is 20-40 wt %, and the etching time is 1-3 h.

[0014] Further, in step S4, the total mass fraction of copper and silver in the nitrogen-doped hollow carbon spheres is 0.5-15wt%, wherein the mass ratio of copper salt to silver salt is Cu:Ag=0.1:0.9-0.9:0.1, the calcination temperature is 500°C-900°C, and the calcination time is 3-3.5h.

[0015] The second aspect of the present invention is to provide the above-mentioned preparation method for preparing nitrogen-doped hollow carbon sphere-loaded copper-silver double single-atom electrocatalytic material.

[0016] The third aspect of the present invention is to provide the above copper-silver double single-atom electrocatalytic material in the electrocatalytic reduction of carbon dioxide to produce C2 + Product applications.

[0017] Furthermore, under normal temperature conditions, electrocatalytic reduction of carbon dioxide to produce C2 + product.

[0018] A fourth aspect of the present invention is to provide a reducing agent for reducing carbon dioxide to C2 + The product comprises the above-mentioned copper-silver double single-atom electrocatalytic material.

[0019] It should be noted that the reducing agent of the present invention is to reduce carbon dioxide by contacting with a raw gas containing carbon dioxide to produce a raw gas containing carbon monoxide or C2 + In some applications, the reducing agent provided by the present invention can also be used to produce carbon monoxide gas.

[0020] The fifth aspect of the present invention is to provide an electrocatalytic CO2 reduction flow cell, which adopts a three-electrode system, including a working electrode, a counter electrode and a reference electrode, and the working electrode is loaded with the above-mentioned copper-silver double single-atom electrocatalytic material.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. The present invention provides a method for preparing a copper-silver double single atom electrocatalytic material, which first provides a nitrogen source and a carbon source by wrapping dopamine hydrochloride with silicon dioxide as a template, and then carbonizing and etching to obtain porous nitrogen-doped hollow carbon spheres with a high specific surface area, thereby obtaining high carbon dioxide adsorption activity and high carbon monoxide desorption activity. Then, by uniformly loading the copper-silver double single atoms on the porous nitrogen-doped hollow carbon spheres and the electronic interaction between the doped nitrogen, the hydrogen evolution reaction is reduced, which greatly improves the selectivity of CO2RR of the copper-silver double single atoms loaded on the porous nitrogen-doped hollow carbon sphere electrocatalytic material.

[0023] 2. The copper-silver double single atom electrocatalytic material provided by the present invention promotes the coverage of surface *CO intermediates through the tandem action of Cu and Ag, and then transfers *CO to the Cu active site through the overflow action, thereby promoting CC coupling, greatly improving the CO2RR production of C2 by the copper-silver double single atom loaded on the porous nitrogen-doped hollow carbon sphere electrocatalytic material. + Product selectivity.

[0024] 3. The preparation method provided by the present invention does not require expensive high-precision equipment, the synthesis process is simple, the operation is convenient, the reaction time is short, the repeatability is reliable, the production cost is low, and it is very suitable for large-scale industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a scanning electron microscope image of the copper-silver double single atoms supported on the porous nitrogen-doped hollow carbon sphere electrocatalytic material prepared in Example 1;

[0026] Figure 2 This is a specific surface area diagram of the copper-silver double single atoms loaded on the porous nitrogen-doped hollow carbon sphere electrocatalytic material prepared in Example 1;

[0027] Figure 3 This is a picture of the current density of the copper-silver double single atoms loaded on the porous nitrogen-doped hollow carbon sphere electrocatalytic material prepared in Example 1 tested using a flow cell;

[0028] Figure 4 This is a diagram of the electrocatalytic Faraday efficiency of the copper-silver double single atoms loaded on the porous nitrogen-doped hollow carbon sphere electrocatalytic material prepared in Example 1 tested using a flow cell;

[0029] Figure 5 is the X-ray diffraction pattern of this embodiment 1;

[0030] Figure 6 The electrocatalytic reduction of carbon dioxide to produce C2 + Comparison of the Faraday efficiencies of the products;

[0031] Figure 7 The electrocatalytic reduction of carbon dioxide to produce C2 + Comparison of the Faradaic efficiencies of the products. DETAILED DESCRIPTION

[0032] In order to explain the technical scheme and beneficial effects of the present invention more clearly, the present invention is described in detail below in conjunction with the accompanying drawings and Examples. It should be clear that the reference drawings described are only partial embodiments of the present invention, which are only used to explain the present invention and cannot be construed as limitations of the present invention. Unless otherwise specified, the equipment and reagents used in the present invention are conventional commercial products in the art.

[0033] The present invention provides a method for preparing a copper-silver double single atom electrocatalytic material, comprising using silicon dioxide as a template, encapsulating hydrochloric acid dopamine, and providing a nitrogen source and a carbon source at the same time, and carbonizing and etching to obtain a porous nitrogen-doped hollow carbon sphere with a high specific surface area and high carbon dioxide adsorption activity. By uniformly advancing and adding a certain mass fraction of copper salt and silver salt, freeze drying and high-temperature calcination, the copper-silver double single atoms are uniformly loaded on the surface of the porous nitrogen-doped hollow carbon sphere, so that they are fully contacted and reacted with carbon dioxide, reducing the progress of hydrogen evolution reaction, and greatly improving the selectivity of carbon dioxide reduction of the copper-silver double single atoms loaded on the porous nitrogen-doped hollow carbon sphere electrocatalytic material. In addition, the synthesis process of the nitrogen-doped porous carbon-loaded copper-silver double single atom electrocatalytic material is simple in procedure and easy to operate.

[0034] Example 1

[0035] This embodiment provides a method for preparing a copper-silver double single-atom electrocatalytic material. The specific steps are as follows:

[0036] (1) Preparation of silica spheres coated with dopamine hydrochloride: 100 mL of deionized water, 30 mL of ethanol, 2 mL of tetraethyl orthosilicate and 3 mL of ammonia water were fully stirred, and then 10 mL of dopamine hydrochloride solution was added. After stirring for 48 hours, the mixture was centrifuged and washed with deionized water and ethanol to obtain silica spheres coated with dopamine hydrochloride;

[0037] (2) Preparation of nitrogen-coated silica spheres: After grinding the dopamine hydrochloride-coated silica spheres, the silica spheres were calcined at 900° C. for 3 h in a nitrogen atmosphere to obtain nitrogen-doped carbon-coated silica spheres;

[0038] (3) Preparation of nitrogen-doped hollow carbon spheres: 1000 mg of nitrogen-doped carbon-coated silica spheres and 30 mL of 30 wt% hydrofluoric acid solution were mixed, stirred for 2 h to remove the silica template, and centrifuged and washed and dried to obtain nitrogen-doped hollow carbon spheres;

[0039] (4) Preparation of copper-silver double single atoms loaded on porous nitrogen-doped hollow carbon sphere electrocatalytic material: The nitrogen-doped hollow carbon spheres were evenly dispersed in deionized water, and Cu(NO3)2 and AgNO3, whose total mass of copper and silver accounted for 1wt% of the nitrogen-doped hollow carbon spheres, were mixed in a mass ratio of Cu:Ag=0.5:0.5, and added to an aqueous solution containing 40mg of nitrogen-doped hollow carbon spheres. After stirring evenly, the mixture was freeze-dried and calcined at 700°C for 3h to obtain copper-silver double single atoms loaded on porous nitrogen-doped hollow carbon sphere electrocatalytic material.

[0040] Example 2

[0041] This embodiment provides a method for preparing a copper-silver double single-atom electrocatalytic material. The specific steps are as follows:

[0042] Basically the same as Example 1, except that, step (4): Cu(NO3)2 and AgNO3, whose total mass of copper and silver accounts for 1wt% of the nitrogen-doped hollow carbon spheres, are mixed in a mass ratio of Cu:Ag=0.3:0.7.

[0043] Example 3

[0044] This embodiment provides a method for preparing a copper-silver double single-atom electrocatalytic material. The specific steps are as follows:

[0045] Basically the same as Example 1, except that, step (4): Cu(NO3)2 and AgNO3, whose total mass of copper and silver accounts for 1wt% of the nitrogen-doped hollow carbon spheres, are mixed in a mass ratio of Cu:Ag=0.7:0.3.

[0046] Example 4

[0047] This embodiment provides a method for preparing a copper-silver double single-atom electrocatalytic material. The specific steps are as follows:

[0048] Basically the same as Example 1, except that, step (4): Cu(NO3)2 and AgNO3, whose total mass of copper and silver accounts for 0.5wt% of the nitrogen-doped hollow carbon spheres, are mixed in a mass ratio of Cu:Ag=0.5:0.5.

[0049] Example 5

[0050] This embodiment provides a method for preparing a copper-silver double single-atom electrocatalytic material. The specific steps are as follows:

[0051] Basically the same as Example 1, except that, step (4): Cu(NO3)2 and AgNO3, whose total mass of copper and silver accounts for 5wt% of the nitrogen-doped hollow carbon spheres, are mixed in a mass ratio of Cu:Ag=0.5:0.5.

[0052] Example 6

[0053] This embodiment provides a method for preparing a copper-silver double single-atom electrocatalytic material. The specific steps are as follows:

[0054] The method is basically the same as Example 1, except that, step (4): calcining at 500° C. for 3 h to obtain a copper-silver double single atom loaded on a porous nitrogen-doped hollow carbon sphere electrocatalytic material.

[0055] Example 7

[0056] This embodiment provides a method for preparing a copper-silver double single-atom electrocatalytic material. The specific steps are as follows:

[0057] The method is basically the same as Example 1, except that, step (4): calcining at 900° C. for 3 h to obtain a copper-silver double single atom loaded on a porous nitrogen-doped hollow carbon sphere electrocatalytic material.

[0058] Example 8

[0059] This embodiment provides a method for preparing a copper-silver double single-atom electrocatalytic material. The specific steps are as follows:

[0060] Basically the same as Example 1, except that, step (4): Cu(NO3)2 and AgCl, whose total mass of copper and silver accounts for 0.7wt% of the nitrogen-doped hollow carbon spheres, are mixed in a mass ratio of Cu:Ag=0.5:0.5, added to an aqueous solution containing 40mg of nitrogen-doped hollow carbon spheres, stirred evenly, freeze-dried, and calcined at 900°C for 3h to obtain a copper-silver double single atom loaded on a porous nitrogen-doped hollow carbon sphere electrocatalytic material.

[0061] Example 9

[0062] This embodiment provides a method for preparing a copper-silver double single-atom electrocatalytic material. The specific steps are as follows:

[0063] Basically the same as Example 1, except that, step (4): Cu(NO3)2 and AgCl, whose total mass of copper and silver accounts for 0.7wt% of the nitrogen-doped hollow carbon spheres, are mixed in a mass ratio of Cu:Ag=0.5:0.5, added to an aqueous solution containing 40mg of nitrogen-doped hollow carbon spheres, stirred evenly, freeze-dried, and calcined at 900°C for 3h to obtain a copper-silver double single atom loaded on a porous nitrogen-doped hollow carbon sphere electrocatalytic material.

[0064] Example 10

[0065] This embodiment provides a method for preparing a copper-silver double single-atom electrocatalytic material. The specific steps are as follows:

[0066] The method is basically the same as Example 1, except that, step (4): Cu(Cl)2 and AgCl, whose total mass of copper and silver accounts for 0.7wt% of the nitrogen-doped hollow carbon spheres, are mixed in a mass ratio of Cu:Ag=0.5:0.5, added to an aqueous solution containing 40mg of nitrogen-doped hollow carbon spheres, stirred evenly, freeze-dried, and calcined at 700°C for 3h to obtain a copper-silver double single atom loaded on a porous nitrogen-doped hollow carbon sphere electrocatalytic material.

[0067] Comparative Example 1

[0068] A preparation method of a nitrogen-doped porous carbon-supported copper single-atom catalyst, the specific steps are as follows:

[0069] (1) Preparation of silica spheres coated with dopamine hydrochloride: 100 mL of deionized water, 30 mL of ethanol, 2 mL of tetraethyl orthosilicate and 3 mL of ammonia water were fully stirred, and then 10 mL of dopamine hydrochloride solution was added. After stirring for 48 h, the mixture was centrifuged and washed with deionized water and ethanol to obtain silica spheres coated with dopamine hydrochloride.

[0070] (2) Preparation of nitrogen-coated silica spheres: The obtained dopamine hydrochloride-coated silica spheres were ground and then calcined at 900° C. for 3 h in a nitrogen atmosphere to obtain nitrogen-doped carbon-coated silica spheres;

[0071] (3) Preparation of nitrogen-doped hollow carbon spheres: 1000 mg of the obtained nitrogen-doped carbon-coated silica spheres were mixed with 30 mL of a 30 wt% hydrofluoric acid solution, stirred for 2 h to remove the silica template, and centrifuged and washed and dried to obtain nitrogen-doped hollow carbon spheres;

[0072] (4) Preparation of porous nitrogen-doped hollow carbon spheres loaded with copper single atom electrocatalytic materials: The obtained nitrogen-doped hollow carbon spheres were evenly dispersed in deionized water, and a Cu(NO3)2 solution in which the total mass of copper accounted for 1 wt% of the nitrogen-doped hollow carbon spheres was added to an aqueous solution containing 40 mg of nitrogen-doped hollow carbon spheres. After stirring evenly, the solution was freeze-dried and calcined at 700°C for 3 h to obtain a nitrogen-doped porous carbon loaded with copper single atom catalyst.

[0073] Comparative Example 2

[0074] A method for preparing a nitrogen-doped porous carbon-supported silver single atom catalyst, the specific steps are as follows:

[0075] (1) Preparation of silica spheres coated with dopamine hydrochloride: 100 mL of deionized water, 30 mL of ethanol, 2 mL of tetraethyl orthosilicate and 3 mL of ammonia water were fully stirred, and then 10 mL of dopamine hydrochloride solution was added. After stirring for 48 hours, the mixture was centrifuged and washed with deionized water and ethanol to obtain silica spheres coated with dopamine hydrochloride;

[0076] (2) Preparation of nitrogen-coated silica spheres: The obtained dopamine hydrochloride-coated silica spheres were ground and then calcined at 900° C. for 3 h in a nitrogen atmosphere to obtain nitrogen-doped carbon-coated silica spheres;

[0077] (3) Preparation of nitrogen-doped hollow carbon spheres: 1000 mg of the obtained nitrogen-doped carbon-coated silica spheres were mixed with 30 mL of a 30 wt% hydrofluoric acid solution, stirred for 2 h to remove the silica template, and centrifuged and washed and dried to obtain nitrogen-doped hollow carbon spheres;

[0078] (4) Preparation of porous nitrogen-doped hollow carbon spheres loaded with silver single atom electrocatalytic materials: The obtained nitrogen-doped hollow carbon spheres were evenly dispersed in deionized water, and a AgNO3 solution in which the total mass of copper accounted for 1 wt% of the nitrogen-doped hollow carbon spheres was added to an aqueous solution containing 40 mg of nitrogen-doped hollow carbon spheres. After stirring evenly, the mixture was freeze-dried and calcined at 700°C for 3 h to obtain a nitrogen-doped porous carbon loaded with silver single atom catalyst.

[0079] The multi-copper-silver double single-atom electrocatalytic materials loaded on porous nitrogen-doped hollow carbon spheres (copper-silver double single-atom electrocatalytic materials) prepared in Examples 1 to 10 all have similar microscopic morphology, structure and catalytic performance, and Example 1 is used as an example for illustration:

[0080] like Figure 1 As shown, it is a scanning electron microscope image of the copper-silver double single atom electrocatalytic material prepared in Example 1. As can be seen from the figure, it has hollow carbon spheres of uniform size, and the copper-silver double single atoms are loaded on the porous nitrogen-doped hollow carbon spheres.

[0081] like Figure 2 As shown in the figure, it is the BET diagram of the copper-silver double single atom electrocatalytic material prepared in Example 1. It can be seen from the figure that the electrocatalytic material has a high 2 / g -1 High specific surface area.

[0082] Figure 3 The current density diagram of the copper-silver double single atom electrocatalyst material prepared in Example 1 is shown in the figure. As can be seen from the figure, the copper-silver double single atom electrocatalyst material prepared in Example 1 loaded on the porous nitrogen-doped hollow carbon sphere electrocatalyst material passes through the electrocatalytic reduction of carbon dioxide to produce C2 + The product has the highest current, up to 560mAcm -2 .

[0083] Figure 4 The electrocatalytic Faraday efficiency diagram of the copper-silver double single-atom electrocatalytic material prepared in Example 1 using a flow cell test. As can be seen from the figure, the copper-silver double single-atom electrocatalytic material prepared in Example 1 loaded on porous nitrogen-doped hollow carbon spheres has extremely high electrocatalytic carbon dioxide reduction to produce C2 + The efficiency of the product is as high as 84%.

[0084] Figure 5 This is the X-ray diffraction diagram of Example 1. It can be seen from the figure that the copper-silver double single atom electrocatalytic material prepared in Example 1 does not have the characteristic peaks of metallic copper and silver, which means that there are no copper and silver nanoparticles, thereby proving the successful preparation of the copper-silver double single atom loaded on the porous nitrogen-doped hollow carbon sphere electrocatalytic material.

[0085] Figure 6is the Faraday efficiency of the electrocatalytic reduction of carbon dioxide to produce carbon monoxide in Example 1 and Comparative Examples 1 and 2. It can be seen from the figure that the electrocatalytic reduction of carbon dioxide to produce C2 + The product efficiency was the highest, reaching 84%.

[0086] Figure 7 is the Faraday efficiency of the electrocatalytic reduction of carbon dioxide to produce carbon monoxide in Example 1 and Examples 2-10. It can be seen from the figure that the electrocatalytic reduction of carbon dioxide to produce C2 + The product efficiency was the highest, reaching 84%.

[0087] Embodiment 11

[0088] Copper-silver double single-atom electrocatalytic material is used for electrocatalytic reduction of carbon dioxide.

[0089] Construct an electrocatalytic flow cell device: place a three-electrode system in an electrolyte containing carbon dioxide for electrolysis; the three-electrode system includes a working electrode, a counter electrode and a reference electrode, wherein the counter electrode is a platinum sheet electrode, the reference electrode is an Ag / AgCl electrode, and the working electrode is a glassy carbon electrode after electrode modification; the electrode modification process is to modify the glassy carbon electrode with a modifier by chemical deposition; the modifier is a copper-silver double single-atom electrocatalytic material. The present invention uses the copper-silver double single-atom electrocatalytic material as a catalyst for electrocatalytic reduction of carbon dioxide.

[0090] The copper-silver double single atom electrocatalytic materials with the porous nitrogen-doped hollow carbon sphere loading ratio prepared in Examples 1 to 10 were tested for the activity of electrocatalytic reduction of carbon dioxide, wherein the mass ratio of the copper-silver double single atoms, the high-temperature calcination deposition temperature and the total mass fraction of copper and silver in the nitrogen-doped hollow carbon spheres were different. Figure 7 The copper-silver double single atoms were loaded on porous nitrogen-doped hollow carbon sphere electrocatalytic materials for electrocatalytic reduction of carbon dioxide to produce C2 at a voltage of -0.8 V. + The activity comparison diagram of the product shows that under this method, the electrocatalytic materials obtained have good performance under different mass ratios of copper-silver double single atoms, different high-temperature calcination deposition temperatures, different total mass fractions of copper-silver in nitrogen-doped hollow carbon spheres, and different copper sources and silver sources. The carbon dioxide reduction reaction of the copper-silver double single atoms prepared in Example 1 loaded on the porous nitrogen-doped hollow carbon sphere electrocatalytic material produces C2 + The product has the highest activity.

[0091] For matters not mentioned above, the prior art applies.

[0092] Although some specific embodiments of the present invention have been described in detail through examples, those skilled in the art should understand that the above examples are for illustration only and are not intended to limit the scope of the present invention. Those skilled in the art to which the present invention belongs may make various modifications or supplements to the specific embodiments described or replace them in a similar manner, but they will not deviate from the direction of the present invention or exceed the scope defined by the attached claims. Those skilled in the art should understand that any modifications, equivalent substitutions, improvements, etc. made to the above embodiments based on the technical essence of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a copper-silver double single-atom electrocatalytic material, characterized in that: The steps include: S1. Preparation of silica spheres wrapped with dopamine hydrochloride: a certain amount of deionized water, ethanol, tetraethyl orthosilicate and ammonia water are mixed and stirred, and then dopamine hydrochloride solution is added and stirred, and carbonization treatment is performed to obtain silica spheres wrapped with dopamine hydrochloride; S2, preparing nitrogen-coated silica spheres: calcining the dopamine hydrochloride-coated silica spheres obtained in step S1 at high temperature to obtain nitrogen-coated silica spheres; S3, preparing nitrogen-doped hollow carbon spheres: adding the nitrogen-doped carbon-coated silica spheres obtained in step S2 into a hydrofluoric acid solution, stirring, centrifugally washing, and drying to obtain nitrogen-doped hollow carbon spheres; S4. Preparation of copper-silver double single-atom electrocatalytic material loaded on porous nitrogen-doped hollow carbon spheres: after uniformly dispersing the nitrogen-doped hollow carbon spheres obtained in step S3 in deionized water, adding copper salt and silver salt and stirring, freezing, drying and calcining to obtain the copper-silver double single-atom electrocatalytic material loaded on nitrogen-doped hollow carbon spheres.

2. The preparation method according to claim 1, characterized in that In step S1, the stirring time of deionized water, ethanol, tetraethyl orthosilicate and ammonia water is 20 to 40 minutes.

3. The preparation method according to claim 1, characterized in that: In step S2, after adding the dopamine hydrochloride solution, the stirring time is 24 to 48 hours, the high-temperature calcination temperature is 700 to 1000° C., and the calcination time is 3 to 3.5 hours.

4. The preparation method according to claim 1, characterized in that: In step S3, the mass ratio of nitrogen-doped carbon-coated silica spheres to hydrofluoric acid is 1:1000; the concentration of the hydrofluoric acid solution is 20-40 wt %, and the etching time is 1-3 h.

5. The preparation method according to claim 1, characterized in that: In step S4, the total mass fraction of copper and silver in the nitrogen-doped hollow carbon spheres is 0.5-15wt%, wherein the mass ratio of copper salt to silver salt is Cu:Ag=0.1:0.9-0.9:0.1, the calcination temperature is 500°C-900°C, and the calcination time is 3-3.5h.

6. The preparation method according to any one of claims 1 to 5 is used to prepare the copper-silver double single atom electrocatalytic material supported by nitrogen-doped hollow carbon spheres.

7. The copper-silver double single-atom electrocatalytic material as claimed in claim 6 is used for electrocatalytic reduction of carbon dioxide to produce C2 + Product applications.

8. The use according to claim 7, characterized in that Under normal temperature conditions, electrocatalytic reduction of carbon dioxide to produce C2 was carried out using 2 mol / L potassium bicarbonate solution as the electrolyte. + product.

9. A reducing agent for reducing carbon dioxide to C2 + The product is characterized in that It comprises the copper-silver double single-atom electrocatalytic material as described in claim 6.

10. An electrocatalytic CO2 reduction flow cell, using a three-electrode system, including a working electrode, a counter electrode and a reference electrode, characterized in that: The working electrode is loaded with the copper-silver double single-atom electrocatalytic material as described in claim 6.

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