A copper-silver dual single-atom electrocatalytic material, its preparation method and application

Abstract

This invention belongs to the field of electrochemical energy materials technology, specifically disclosing a copper-silver dual-single-atom electrocatalytic material, its preparation method, and its application. The preparation method involves using silica as a template to encapsulate dopamine hydrochloride as a nitrogen and carbon source, followed by carbonization and etching to obtain porous nitrogen-doped hollow carbon spheres with high specific surface area, thereby achieving high carbon dioxide adsorption activity and high carbon monoxide desorption activity. Then, through the uniform loading of copper-silver dual-single atoms on the porous nitrogen-doped hollow carbon spheres and the electronic interactions between the doped nitrogen atoms, the hydrogen evolution reaction is reduced, significantly improving the selectivity of the CO2RR of the copper-silver dual-single-atom electrocatalytic material loaded on porous nitrogen-doped hollow carbon spheres. The copper-silver dual-single-atom electrocatalytic material provided by this invention is used for the electrocatalytic reduction of carbon dioxide. The synthesis process is simple, convenient, has a short reaction time, reliable reproducibility, and low production cost, making it very suitable for large-scale industrial production.

Description

Technical Field

[0001] This invention relates to the field of electrochemical energy materials technology, and in particular to a copper-silver dual single-atom electrocatalytic material, its preparation method, and its application. Background Technology

[0002] Electrocatalytic reduction of carbon dioxide (CO2RR) is considered a promising pathway to convert carbon dioxide into value-added chemicals via an electrochemical process. While significant progress has been made in the industrial application of reducing carbon dioxide to C1 products in recent years, the formation of C1 products with higher energy density and greater commercial value remains a challenge. n , n≥2(C2 + Multi-carbon molecules are more ideal, but still challenging.

[0003] Copper-based materials are widely used in the production of C2 from CO2RR due to their unique C-coupling ability. + Products. *CO and CO-related intermediates (such as *OCCO) have been shown to form C2 via dimerization or coupling. + The key intermediate of the product. Increased *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 remain 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 high surface coverage of *CO intermediates, and then transfer *CO to Cu active sites via spillover. This ingenious design, by dividing the reaction into different steps through multiple local catalytic sites in the CO generation catalyst / Cu-based material, acts as a tandem catalyst for the conversion of CO2RR to C2. + The products are attractive. Therefore, compared with single-phase catalysts, how to design and adjust different structural units in tandem catalysts to achieve multifunctional synergistic optimization, including C / C coupling, CO generation, and spillover, is an urgent problem to be solved. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by providing a copper-silver dual-single-atom electrocatalytic material, its preparation method, and its applications. Porous nitrogen-doped hollow carbon spheres are prepared using a silica template method, and further, copper-silver dual-single-atom materials supported on these porous nitrogen-doped hollow carbon spheres are prepared using a liquid nitrogen freezing and thermal decomposition method, thereby improving carbon dioxide adsorption activity. Through the tandem interaction of Cu and Ag, the surface coverage of *CO intermediates is increased, and then *CO is transferred to Cu active sites via overflow, thus promoting CC coupling and significantly improving the CO2RR production of C2 from the copper-silver dual-single-atom supported porous nitrogen-doped hollow carbon sphere electrocatalytic material. + Product selectivity.

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

[0006] S1. Preparation of silica spheres coated with dopamine hydrochloride: A certain amount of deionized water, ethanol, tetraethyl orthosilicate and ammonia water are mixed and stirred. Then, dopamine hydrochloride solution is added and stirred. Carbonization treatment is performed to obtain silica spheres coated with dopamine hydrochloride.

[0007] S2. Preparation of nitrogen-coated silica spheres: The silica spheres coated with dopamine hydrochloride obtained in step S1 are calcined at high temperature to obtain nitrogen-coated silica spheres.

[0008] S3. Preparation of nitrogen-doped hollow carbon spheres: The nitrogen-doped carbon-coated silica spheres obtained in step S2 are added to a hydrofluoric acid solution, stirred, centrifuged, washed, and dried to obtain nitrogen-doped hollow carbon spheres.

[0009] S4. Preparation of copper-silver dual single-atom supported porous nitrogen-doped hollow carbon sphere electrocatalytic material: After uniformly dispersing the nitrogen-doped hollow carbon spheres obtained in step S3 in deionized water, copper salt and silver salt were added, and the mixture was stirred, frozen, dried, and calcined to obtain the copper-silver dual single-atom electrocatalytic material supported on nitrogen-doped hollow carbon spheres.

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

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

[0012] Furthermore, in step S3, the mass ratio of nitrogen-doped carbon-coated silica spheres to 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] Furthermore, in step S4, the total mass fraction of copper and silver in the nitrogen-doped hollow carbon spheres is 0.5–15 wt%, 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℃–900℃, and the calcination time is 3–3.5 h.

[0015] A second aspect of the present invention is to provide a method for preparing a copper-silver dual-single-atom electrocatalytic material supported on nitrogen-doped hollow carbon spheres using the above-described preparation method.

[0016] A third aspect of the present invention is to provide the above-mentioned copper-silver dual single-atom electrocatalytic material for the electrocatalytic reduction of carbon dioxide to C2. + Applications in product development.

[0017] Furthermore, under ambient temperature conditions and with a 2 mol / L potassium bicarbonate solution as the electrolyte, the electrocatalytic reduction of carbon dioxide to C2 was carried out. + product.

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

[0019] It should be noted that the reducing agent of the present invention reduces carbon dioxide by contacting it with a raw material gas containing carbon dioxide, thereby producing a product containing carbon monoxide or C2. + Products. In some applications, the reducing agent provided by this invention can also be used to produce carbon monoxide gas.

[0020] A fifth aspect of the present invention is to provide an electrocatalytic CO2 reduction flow cell employing a three-electrode system, comprising a working electrode, a counter electrode, and a reference electrode, wherein the working electrode is loaded with the aforementioned copper-silver dual-monoatomic electrocatalytic material.

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

[0022] 1. This invention provides a method for preparing a copper-silver dual-single-atom electrocatalytic material. First, a nitrogen and carbon source is provided by encapsulating dopamine hydrochloride using silica as a template. Carbonization and etching are then performed to obtain porous nitrogen-doped hollow carbon spheres with high specific surface area, thereby achieving high carbon dioxide adsorption activity and high carbon monoxide desorption activity. Then, through the uniform loading of copper-silver dual-single atoms on the porous nitrogen-doped hollow carbon spheres and the electronic interactions between the doped nitrogen atoms, the hydrogen evolution reaction is reduced, significantly improving the selectivity of the CO2RR of the copper-silver dual-single-atom-loaded porous nitrogen-doped hollow carbon sphere electrocatalytic material.

[0023] 2. The copper-silver dual-single-atom electrocatalytic material provided by this invention promotes the coverage of *CO intermediates on the surface through the tandem interaction of Cu and Ag, and then transfers *CO to Cu active sites through overflow, thereby promoting CC coupling. This greatly improves the CO2RR production of C2 on copper-silver dual-single-atom electrocatalytic materials supported on porous nitrogen-doped hollow carbon spheres. + Product selectivity.

[0024] 3. The preparation method provided by this invention does not require expensive high-precision equipment. The synthesis process is simple, easy to operate, has a short reaction time, reliable repeatability, and low production cost, making it very suitable for large-scale industrial production. Attached Figure Description

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

[0027] Figure 3 Image showing the current density of the copper-silver dual single-atom supported on porous nitrogen-doped hollow carbon sphere electrocatalytic material prepared in Example 1, tested using a flow cell.

[0028] Figure 4 The image shows the Faraday efficiency of the copper-silver dual single-atom supported porous nitrogen-doped hollow carbon sphere electrocatalytic material prepared in Example 1, tested using a flow cell.

[0029] Figure 5 This is the X-ray diffraction pattern of Example 1.

[0030] Figure 6 This refers to the electrocatalytic reduction of carbon dioxide to C2 in Example 1 and Comparative Examples 1 and 2. + A comparison chart of the Faraday efficiency of the products;

[0031] Figure 7 Electrocatalytic carbon dioxide reduction to C2 production in Examples 1-10 + A comparison chart of the Faraday efficiency of the products. Detailed Implementation

[0032] To more clearly explain the technical solution and beneficial effects of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and embodiments. It should be noted that the described accompanying drawings are only some embodiments of the present invention and are used only to explain the present invention, and should not be construed as limiting the present invention. Unless otherwise specified, the equipment and reagents used in the present invention are commercially available products conventional in this technical field.

[0033] This invention provides a method for preparing a copper-silver dual-single-atom electrocatalytic material, comprising using silica as a template to encapsulate dopamine hydrochloride, providing both nitrogen and carbon sources, followed by carbonization and etching to obtain porous nitrogen-doped hollow carbon spheres with high specific surface area and high carbon dioxide adsorption activity. By uniformly adding a certain mass fraction of copper and silver salts, followed by freeze-drying and high-temperature calcination, the copper-silver dual-single atoms are uniformly loaded onto the surface of the porous nitrogen-doped hollow carbon spheres, thereby ensuring sufficient contact and reaction with carbon dioxide, reducing the hydrogen evolution reaction, and significantly improving the selectivity of carbon dioxide reduction in the copper-silver dual-single-atom supported porous nitrogen-doped hollow carbon sphere electrocatalytic material. Furthermore, the synthesis process of the nitrogen-doped porous carbon supported copper-silver dual-single-atom electrocatalytic material is simple and convenient.

[0034] Example 1

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

[0036] (1) Preparation of silica spheres coated with dopamine hydrochloride: After thoroughly stirring 100 mL of deionized water, 30 mL of ethanol, 2 mL of tetraethyl orthosilicate and 3 mL of ammonia, add 10 mL of dopamine hydrochloride solution, stir for 48 h, and then centrifuge and wash with deionized water and ethanol to obtain silica spheres coated with dopamine hydrochloride.

[0037] (2) Preparation of nitrogen-coated silica spheres: After grinding the silica spheres coated with dopamine hydrochloride, they were calcined at 900°C for 3 hours under 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 and stirred for 2 h to remove the silica template. After centrifugation, washing and drying, nitrogen-doped hollow carbon spheres were obtained.

[0039] (4) Preparation of copper-silver dual single-atom supported porous nitrogen-doped hollow carbon sphere electrocatalytic material: Nitrogen-doped hollow carbon spheres were uniformly dispersed in deionized water. Cu(NO3)2 and AgNO3, with a total mass of copper and silver accounting for 1 wt% of the nitrogen-doped hollow carbon spheres, were mixed at a mass ratio of Cu:Ag = 0.5:0.5 and 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℃ for 3 h to obtain copper-silver dual single-atom supported porous nitrogen-doped hollow carbon sphere electrocatalytic material.

[0040] Example 2

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

[0042] The process is basically the same as in Example 1, except that in step (4): Cu(NO3)2 and AgNO3, whose total mass of copper and silver accounts for 1 wt% 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 dual single-atom electrocatalytic material. The specific steps are as follows:

[0045] The process is basically the same as in Example 1, except that in step (4): Cu(NO3)2 and AgNO3, whose total mass of copper and silver accounts for 1 wt% 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 dual single-atom electrocatalytic material. The specific steps are as follows:

[0048] The process is basically the same as in Example 1, except that in step (4): Cu(NO3)2 and AgNO3, whose total mass of copper and silver accounts for 0.5 wt% 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 dual single-atom electrocatalytic material. The specific steps are as follows:

[0051] The process is basically the same as in Example 1, except that in step (4): Cu(NO3)2 and AgNO3, whose total mass of copper and silver accounts for 5 wt% 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 dual single-atom electrocatalytic material. The specific steps are as follows:

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

[0055] Example 7

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

[0057] The process is basically the same as in Example 1, except that step (4) involves calcining the material at 900°C for 3 hours to obtain copper-silver double single-atom supported porous nitrogen-doped hollow carbon sphere electrocatalytic material.

[0058] Example 8

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

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

[0061] Example 9

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

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

[0064] Example 10

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

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

[0067] Comparative Example 1

[0068] The specific steps for preparing a nitrogen-doped porous carbon-supported copper single-atom catalyst are as follows:

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

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

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

[0072] (4) Preparation of porous nitrogen-doped hollow carbon sphere supported copper single-atom electrocatalytic material: The obtained nitrogen-doped hollow carbon spheres were uniformly dispersed in deionized water. A Cu(NO3)2 solution with a total copper mass of 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℃ for 3 h to obtain a nitrogen-doped porous carbon supported 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 of which are as follows:

[0075] (1) Preparation of silica spheres coated with dopamine hydrochloride: After thoroughly stirring 100 mL of deionized water, 30 mL of ethanol, 2 mL of tetraethyl orthosilicate and 3 mL of ammonia, add 10 mL of dopamine hydrochloride solution, stir for 48 h, and then centrifuge and wash with deionized water and ethanol to obtain silica spheres coated with dopamine hydrochloride.

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

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

[0078] (4) Preparation of porous nitrogen-doped hollow carbon spheres supported on silver single-atom electrocatalytic material: The obtained nitrogen-doped hollow carbon spheres were uniformly dispersed in deionized water. An AgNO3 solution with a total copper mass of 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℃ for 3 h to obtain a nitrogen-doped porous carbon supported on silver single-atom catalyst.

[0079] The copper-silver dual single-atom electrocatalytic materials (copper-silver dual single-atom electrocatalytic materials) prepared in Examples 1-10 all exhibit similar microstructures, structures, and catalytic performance. Example 1 is used as an example for illustration:

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

[0081] like Figure 2 The figure shows the BET curve of the copper-silver dual single-atom electrocatalytic material prepared in Example 1. As can be seen from the figure, this electrocatalytic material has a high BET curve of up to 1841 m. 2 / g -1 High specific surface area.

[0082] Figure 3 This is a current density diagram of the copper-silver dual-monoatomic electrocatalytic material prepared in Example 1. As shown in the diagram, the copper-silver dual-monoatomic material prepared in Example 1, loaded onto porous nitrogen-doped hollow carbon spheres, provides current density per unit area for the electrocatalytic reduction of carbon dioxide to C2. + The product has the highest current, reaching 560 mA / cm. -2 .

[0083] Figure 4 The graph shows the electrocatalytic Faraday efficiency of the copper-silver dual-single-atom electrocatalytic material prepared in Example 1, tested using a flow cell. As can be seen from the graph, the copper-silver dual-single-atom electrocatalytic material prepared in Example 1, supported on porous nitrogen-doped hollow carbon spheres, exhibits extremely high electrocatalytic efficiency for the reduction of carbon dioxide to C2. + The product efficiency is as high as 84%.

[0084] Figure 5 The image shows the X-ray diffraction pattern of Example 1. As can be seen from the image, the copper-silver dual-monoatomic electrocatalytic material prepared in Example 1 does not show the characteristic peaks of metallic copper and silver, which means that there are no copper and silver nanoparticles. This proves the successful preparation of copper-silver dual-monoatomic loaded on porous nitrogen-doped hollow carbon sphere electrocatalytic material.

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

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

[0087] Example 11

[0088] Copper-silver dual single-atom electrocatalytic materials are used for the electrocatalytic reduction of carbon dioxide.

[0089] An electrocatalytic flow cell device was constructed: a three-electrode system was placed in a carbon dioxide-containing electrolyte for electrolysis; the three-electrode system included a working electrode, a counter electrode, and a reference electrode, wherein the counter electrode was a platinum sheet electrode, the reference electrode was an Ag / AgCl electrode, and the working electrode was a modified glassy carbon electrode; the electrode modification process involved modifying the glassy carbon electrode with a modifier via chemical deposition; the modifier was a copper-silver dual-monoatom electrocatalytic material. This invention uses a copper-silver dual-monoatom electrocatalytic material as a catalyst for the electrocatalytic reduction of carbon dioxide.

[0090] The copper-silver dual-single-atom electrocatalytic materials with porous nitrogen-doped hollow carbon sphere loading ratios prepared in Examples 1-10 were tested for their electrocatalytic reduction of carbon dioxide. The mass ratio of copper-silver dual-single-atom materials, 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 This study tested the electrocatalytic reduction of carbon dioxide to C2 using copper-silver dual single-atom supported porous nitrogen-doped hollow carbon sphere electrocatalytic material at -0.8V. + The activity comparison diagram of the products shows that, under this method, the electrocatalytic materials obtained with different mass ratios of copper and silver duomonatoms, different high-temperature calcination deposition temperatures, different copper and silver percentages in the total mass of nitrogen-doped hollow carbon spheres, and different copper and silver sources all exhibit good performance. Among them, the copper-silver duomonatoms prepared in Example 1, loaded onto porous nitrogen-doped hollow carbon sphere electrocatalytic materials, demonstrate particularly good performance in the carbon dioxide reduction reaction for C2 production. + The product has the highest activity.

[0091] For any points not covered above, existing technologies shall apply.

[0092] Although specific embodiments of the present invention have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and are not intended to limit the scope of the invention. Those skilled in the art can make various modifications or additions to the described specific embodiments or use similar methods to replace them, without departing from the direction of the invention or exceeding the scope defined by the appended 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 within the protection scope of the present invention.

Claims

1. A copper-silver biatomic electrocatalytic material for electrocatalytic reduction of carbon dioxide to C2 in the presence of water. + The use of the product is characterized in that, The preparation method of the copper-silver double-atomic electrocatalytic material comprises the following steps: S1, preparing dopamine hydrochloride coated silica balls: a certain amount of deionized water, ethanol, tetraethyl orthosilicate and ammonia water are mixed under stirring, and then a dopamine hydrochloride solution is added and stirred to obtain dopamine hydrochloride coated silica balls; S2, preparing nitrogen coated silica balls: the dopamine hydrochloride coated silica balls obtained in step S1 are calcined at high temperature to obtain nitrogen coated silica balls; S3, preparing nitrogen doped hollow carbon balls: the nitrogen doped carbon coated silica balls obtained in step S2 are added to a hydrofluoric acid solution, stirred, centrifuged, washed and dried to obtain nitrogen doped hollow carbon balls; S4, preparing copper-silver double-atomic electrocatalytic material loaded on porous nitrogen doped hollow carbon balls: the nitrogen doped hollow carbon balls obtained in step S3 are uniformly dispersed in deionized water, then copper salt and silver salt are added and stirred, frozen, dried and calcined to obtain the copper-silver double-atomic electrocatalytic material loaded on nitrogen doped hollow carbon balls; The total mass fraction of copper and silver in the nitrogen doped hollow carbon balls is 0.7-1wt%, the mass ratio of copper salt to silver salt is Cu:Ag = 0.3:0.7-0.7:0.3, the calcination temperature is 500-900°C, and the calcination time is 3-3.5h.

2. Use according to claim 1, wherein In step S1, the stirring time of deionized water, ethanol, tetraethyl orthosilicate and ammonia water is 20-40min.

3. The use according to claim 1, wherein In step S2, after adding the dopamine hydrochloride solution, the stirring time is 24-48h, the high-temperature calcination temperature is 700-1000°C, and the calcination time is 3-3.5h.

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

5. The use according to claim 1, wherein A three-electrode system is used, including a working electrode, a counter electrode and a reference electrode, and the copper-silver double-atomic electrocatalytic material is loaded on the working electrode.

6. Use according to claim 1, characterized in that, The electrocatalytic reduction of carbon dioxide to produce C2 under the condition of 2 mol / L potassium bicarbonate solution as electrolyte at room temperature + products.

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