Copper-oxygen coordination controllable and anti-reconstruction copper-based electrocatalyst, and preparation method and application thereof

Abstract

The invention provides a copper-oxygen coordination controllable and anti-reconstruction copper-based electrocatalyst, and a preparation method and application thereof. The preparation method comprises the following steps: S1, providing a CuO precursor; s2, mixing a CuO precursor with Nafion, and then coating the surface of the substrate electrode with the mixture to obtain a CuO precursor electrode; s3, placing the CuO precursor electrode in a first electrolyte at normal temperature and normal pressure, and modifying the surface of the CuO precursor electrode with polyphenylenediamine by a cyclic voltammetry method to obtain a modified electrode; and S4, placing the modified electrode in a second electrolyte at normal temperature and normal pressure, and performing in-situ reduction on the CuO precursor by a constant voltage method to obtain the copper-based electrocatalyst. According to the invention, a method for in-situ reduction of a CuO precursor under a specific mesoscopic morphology is adopted to obtain the anti-reconstruction oxide-derived copper (OD-Cu) catalyst with controllable Cu-O coordination number, and the catalyst has high electro-catalytic activity, high selectivity and high stability in carbon dioxide electro-reduction reaction.

Description

Technical Field

[0001] The present invention belongs to the technical field of inorganic nanocatalytic materials, and in particular relates to a copper-based electrocatalyst with controllable copper-oxygen coordination and anti-reconstruction, a preparation method and application thereof. Background Art

[0002] As global climate change and energy crisis become increasingly severe, it is particularly important to find sustainable energy solutions. As a major greenhouse gas, the increase in carbon dioxide (CO2) emissions has had a serious impact on the environment. However, CO2 is also a rich carbon source that can be converted into valuable multi-carbon chemicals such as ethylene, ethanol, and propane through electrochemical reduction reaction (CO2ERR), which not only helps reduce greenhouse gas emissions but also provides a potential solution to the energy crisis.

[0003] In CO2ERR, copper (Cu)-based catalysts have attracted much attention due to their unique advantages in the formation of multi-carbon products. The performance of copper-based catalysts is affected by many factors, including the Cu content in the catalyst. δ+ The existence of substances, the dimensional characteristics of the catalyst, and the surface structure of the catalyst. δ+ The presence of substances will affect the adsorption of the catalyst on the intermediates of the CO2 reduction reaction, thereby affecting the C 2+ In addition, the dimensional characteristics and surface structure of the catalyst will also affect the mass and charge transfer efficiency during the reaction, thereby affecting the overall performance of the catalyst.

[0004] Although a variety of Cu-based electrocatalysts have been studied and developed, they still face challenges in terms of stability and structure-activity relationship establishment in the CO2ER process. In particular, oxide-derived copper (OD-Cu) catalysts, despite their rich Cu-O coordination and specific structural features such as grain boundaries, crystal planes, and Cu δ+ However, during the CO2ERR process, these catalysts often undergo reconstruction, resulting in the destruction of the structure and characteristics of the catalysts, which is not only not conducive to the stability of the catalyst performance, but also not conducive to a deep understanding of the structure-activity relationship of the catalyst.

[0005] Therefore, it is necessary to provide an improved technical solution to address the above-mentioned deficiencies in the prior art. Summary of the invention

[0006] In view of the shortcomings of the prior art mentioned above, the object of the present invention is to provide a copper-based electrocatalyst with controllable copper-oxygen coordination and resistance to reconstruction, a preparation method and its application, so as to solve the problem of uncontrollable copper-oxygen coordination in copper-based electrocatalysts in the prior art, and the problem that the catalyst is easily reconstructed during the electrochemical reduction reaction, resulting in the destruction of the structure and characteristics of the catalyst.

[0007] To achieve the above objectives and other related objectives, the present invention provides a method for preparing a copper-based electrocatalyst with controllable copper-oxygen coordination and anti-reconstruction, the preparation method comprising the following steps:

[0008] S1. providing a CuO precursor;

[0009] S2, mixing the CuO precursor with Nafion to form a mixed solution, and then applying the mixed solution to the surface of the base electrode to obtain a CuO precursor electrode loaded with the CuO precursor;

[0010] S3, placing the CuO precursor electrode in a first electrolyte at room temperature and pressure, and modifying the surface of the CuO precursor electrode with polyphenylenediamine by cyclic voltammetry to obtain a modified electrode;

[0011] S4. At room temperature and pressure, the modified electrode is placed in a second electrolyte, and a CuO precursor is in situ reduced by a constant voltage method to obtain a copper-based electrocatalyst with controllable copper-oxygen coordination and resistance to reconstruction.

[0012] Preferably, the preparation method of the CuO precursor in step S1 is one of direct precipitation method, precipitation conversion method and hydrothermal synthesis method.

[0013] Preferably, the mesoscopic dimensional characteristics of the CuO precursor in step S1 are one or a combination of zero-dimensional, one-dimensional, two-dimensional, and three-dimensional characteristics.

[0014] Preferably, the base electrode in step S2 comprises one of carbon paper, carbon cloth and titanium sheet.

[0015] Preferably, in step S2, the loading amount of the CuO precursor on the substrate electrode is 0.1-2 mg cm -2 .

[0016] Preferably, in step S3, the first electrolyte comprises a mixture of 0.01-1M phosphate buffer solution and 0.01-1M phenylenediamine; wherein the pH value of the phosphate buffer solution is 7.0; and the phenylenediamine is one or more of o-phenylenediamine, m-phenylenediamine, and p-phenylenediamine.

[0017] Preferably, the voltage range of the cyclic voltammetry in step S3 is -0.4 to 0.7 V, the number of scans is 2 to 100, and the scan rate is 2 to 100 mVs -1 .

[0018] Preferably, in step S4, the second electrolyte is one of 0.01-5M NaHCO3 and 0.01-5M KHCO3.

[0019] Preferably, the voltage of the in-situ reduction in step S4 is -0.8 to -2.5 V vs RHE, and the application time of the in-situ reduction is 1 to 24 h.

[0020] The present invention also provides a copper-based electrocatalyst with controllable copper-oxygen coordination and anti-reconstruction. The copper-based electrocatalyst is prepared by adopting the preparation method of the copper-based electrocatalyst with controllable copper-oxygen coordination and anti-reconstruction.

[0021] The present invention also provides an application of a copper-based electrocatalyst with controllable copper-oxygen coordination and resistance to reconstruction, and the application of the copper-based electrocatalyst in the carbon dioxide electroreduction reaction, wherein the copper-based electrocatalyst is prepared by adopting the above-mentioned preparation method of the copper-based electrocatalyst with controllable copper-oxygen coordination and resistance to reconstruction.

[0022] Preferably, the reaction time of the carbon dioxide electroreduction reaction is 0.5 to 72 hours.

[0023] Preferably, the applied voltage for the carbon dioxide electroreduction reaction is -0.5 to -2.0 V vs. RHE.

[0024] Preferably, the electrolyte in the carbon dioxide electroreduction reaction is one of 0.1-1M KHCO3, 0.1-1M NaHCO3, 0.1-1M KOH, and 0.1-1M NaOH.

[0025] As described above, the copper-oxygen coordination controllable and reconstruction-resistant copper-based electrocatalyst, preparation method and application thereof of the present invention have the following beneficial effects:

[0026] The present invention provides a method for preparing a copper-based electrocatalyst with high efficiency, controllable copper-oxygen coordination, low cost and anti-reconstruction. The method adopts a method of in-situ reduction of a CuO precursor under a specific mesoscopic morphology to obtain an oxide-derived copper (OD-Cu) catalyst with controllable Cu-O coordination number and anti-reconstruction. The preparation method is simple and the result is controllable. The prepared copper-based electrocatalyst has high electrocatalytic activity, high selectivity and high stability in the carbon dioxide electroreduction reaction. The copper-based electrocatalyst is applied to the electrocatalytic carbon dioxide reduction reaction, especially to the reaction of electrocatalytic carbon dioxide conversion to generate multi-carbon products, which can effectively solve the problem that the copper-based catalyst in the prior art affects C 2+ The problem of low product selectivity. The copper-based electrocatalyst in the present invention is resistant to reconstruction in the electrochemical reduction reaction, and the copper-oxygen coordination number of the constructed catalyst is high. In the carbon dioxide electroreduction reaction at room temperature and pressure, the total Faraday efficiency of the generated multi-carbon products is as high as 77%, which has extremely high application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Shown is a SEM image of the CuO precursor provided in Example 1 of the present invention.

[0028] Figure 2 Shown is a SEM image of the copper-based electrocatalyst prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0029] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0030] Before further describing the specific embodiments of the present invention, it should be understood that the scope of protection of the present invention is not limited to the specific embodiments described below; it should also be understood that the terms used in the examples of the present invention are intended to describe specific embodiments, rather than to limit the scope of protection of the present invention. The test methods in the following examples without specifying specific conditions are generally carried out under conventional conditions or under conditions recommended by the manufacturers.

[0031] When the embodiments give numerical ranges, it should be understood that, unless otherwise specified in the present invention, both endpoints of each numerical range and any numerical value between the two endpoints can be selected. Unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as those generally understood by those skilled in the art. In addition to the specific methods, equipment, and materials used in the embodiments, according to the grasp of the prior art by those skilled in the art and the record of the present invention, any methods, equipment, and materials of the prior art similar or equivalent to the methods, equipment, and materials described in the embodiments of the present invention can also be used to realize the present invention.

[0032] A method for preparing a copper-based electrocatalyst with controllable copper-oxygen coordination and anti-reconstruction, the preparation method comprising the following steps:

[0033] S1. providing a CuO precursor;

[0034] S2, mixing the CuO precursor with Nafion to form a mixed solution, and then applying the mixed solution to the surface of the base electrode to obtain a CuO precursor electrode loaded with the CuO precursor;

[0035] S3, placing a CuO precursor electrode in a first electrolyte at room temperature and pressure, and modifying the surface of the CuO precursor electrode with polyphenylenediamine by cyclic voltammetry to obtain a modified electrode;

[0036] S4. At room temperature and pressure, the modified electrode is placed in a second electrolyte, and the CuO precursor is reduced in situ using a constant voltage method to obtain a copper-based electrocatalyst with controllable copper-oxygen coordination and resistance to reconstruction.

[0037] Specifically, the Nafion in step S2 is a perfluorosulfonic acid-polytetrafluoroethylene copolymer, which has a certain bonding effect and can solidify the catalyst in the process of changing from liquid to solid. In addition, the sulfonic acid in Nafion has an electrostatic effect based on the amino group in polyphenylenediamine, which can improve the bonding degree between the sulfonic acid and the polyphenylenediamine. In addition, the presence of Nafion allows a dense and non-detachable polyphenylenediamine layer to be formed on the surface of the catalyst; and polyphenylenediamine is an electropolymer material with self-limited thickness and can achieve uniform coverage, with a thickness of only a few nanometers. Its coverage on the surface of the CuO precursor can enable CuO to better maintain its initial structure during the subsequent in-situ reduction process of preparing a copper-based catalyst.

[0038] In a specific embodiment of the present invention, the mass ratio between the CuO precursor and Nafion is 1:1 to 10:1; preferably, Nafion is a solution with a mass fraction of 0.5 wt.%.

[0039] The present invention provides a method for preparing a copper-based electrocatalyst with high efficiency, controllable copper-oxygen coordination, low cost and resistance to reconstruction. The method adopts a method of in-situ reduction of a CuO precursor with a specific mesoscopic morphology to obtain an oxide-derived copper (OD-Cu) catalyst with controllable Cu-O coordination number and resistance to reconstruction. The preparation method is simple and the result is controllable.

[0040] As an example, the preparation method of the CuO precursor in step S1 is one of direct precipitation method, precipitation conversion method and hydrothermal synthesis method.

[0041] Specifically, the preparation method of the CuO precursor by direct precipitation method includes: adding a certain concentration of NaOH solution dropwise into a certain concentration of CuCl2·2H2O solution, stirring at room temperature for a certain period of time, filtering and washing to obtain blue Cu(OH)2 nanowires, and finally placing the Cu(OH)2 nanowires in a muffle furnace at 2℃min -1 The temperature was raised to 200°C and maintained for 2 h to obtain one-dimensional CuO nanowires.

[0042] The preparation method of the CuO precursor using the precipitation conversion method specifically includes: adding a certain amount of ammonia water to the copper acetate solution, stirring evenly, and then adding a certain concentration of sodium carbonate solution, then placing the mixed solution in a conical flask, bathing it in a 95°C water bath for 2 hours, filtering, washing, and drying to obtain three-dimensional CuO nanoflowers.

[0043] The preparation method of the CuO precursor using a hydrothermal synthesis method specifically includes: adding a certain concentration of NaOH solution dropwise into a certain concentration of CuCl2·2H2O solution, stirring evenly at room temperature, transferring the solution to a hydrothermal kettle, hydrothermally reacting at 120°C for 12 hours, filtering and washing the precipitate, and obtaining a two-dimensional CuO nanosheet.

[0044] As an example, the mesoscopic dimensional characteristics of the CuO precursor in step S1 are one or a combination of zero-dimensional, one-dimensional, two-dimensional, and three-dimensional characteristics.

[0045] Preferably, the mesoscopic dimension of the CuO precursor is characterized by one-dimensional CuO nanowires.

[0046] As an example, in step S2, the base electrode includes one of carbon paper, carbon cloth, and titanium sheet.

[0047] As an example, in step S2, on the electrode loaded with the CuO precursor, the loading amount of the CuO precursor on the substrate electrode is 0.1-2 mg cm -2 .

[0048] Specifically, on the electrode loaded with the CuO precursor, the loading amount of the CuO precursor on the substrate electrode may include 0.1 mg cm -2 , 0.5mg cm -2 , 1mg cm -2 , 1.5 mg cm -2 , 2mg cm -2 Preferably, the loading amount is 0.5 to 1 mg cm -2 (e.g. 0.5 mg cm -2 , 0.6mg cm -2 , 0.7mg cm -2 , 0.8mg cm -2 , 0.9mg cm -2 、1mgcm -2 any range of values).

[0049] As an example, the first electrolyte in step S3 includes a mixture of 0.01 to 1 M (e.g., 0.01 M, 0.05 M, 0.01 M, 0.05 M, 0.1 M, 0.5 M, 1 M, etc.) of phosphate buffer solution (PBS) and 0.01 to 1 M (e.g., 0.01 M, 0.05 M, 0.01 M, 0.05 M, 0.1 M, 0.5 M, 1 M, etc.) of phenylenediamine, wherein the pH value of the phosphate buffer solution is 7.0; and the phenylenediamine is one or more of p-phenylenediamine, o-phenylenediamine or m-phenylenediamine.

[0050] As an example, the voltage range in the cyclic voltammetry in step S3 is -0.4 to 0.7 V, the number of scans is 2 to 100, and the scan rate is 2 to 100 mVs -1 . .

[0051] Specifically, the voltage range in the cyclic voltammetry in step S3 may include values ​​in any range of -0.4 to 0.4 V, -0.4 to 0.5 V, -0.4 to 0.7 V, -0.3 to 0.6 V, etc.; the number of scans may include values ​​in any range of 2, 10, 20, 50, 80, 100, etc.; the scan rate may include 2 mVs -1 , 10mVs -1 , 20mVs -1 , 50mVs -1 、80mVs -1 , 100mVs -1 Any value in the range.

[0052] As an example, the second electrolyte in step S4 is one of 0.01-5M (such as 0.01M, 0.05M, 0.1M, 1M, 2M, 3M, 4M, 5M, etc.) NaHCO3 and 0.01-5M (such as 0.01M, 0.05M, 0.1M, 1M, 2M, 3M, 4M, 5M, etc.) KHCO3.

[0053] Preferably, the second electrolyte is 0.1-1M (eg, 0.1M, 0.2M, 0.4M, 0.6M, 0.8M, 1M, etc.) KHCO3.

[0054] As an example, the voltage of the in-situ reduction in step S4 is -0.8 to -2.5 V vs RHE, and the application time of the in-situ reduction is 1 to 24 hours.

[0055] Specifically, the voltage for the in-situ reduction in step S4 may include a value within any range such as -0.8 V vs RHE, -0.5 V vs RHE, -1 V vs RHE, -1.5 V vs RHE, -2.0 V vs RHE, -2.5 V vs RHE, etc., and the application time for the in-situ reduction may include a value within any range such as 1 h, 6 h, 12 h, 18 h, 24 h, etc.

[0056] Preferably, the voltage of the in-situ reduction in step S4 is -1.2 to -2.0 V vs RHE (e.g., -1.2 V vs RHE, -1.5 V vs RHE, -1.8 V vs RHE, -2.0 V vs RHE, etc.), and the application time of the in-situ reduction is 1.5 to 10 h (e.g., 1.5 h, 2 h, 4 h, 6 h, 8 h, 10 h, etc.).

[0057] The present invention also provides a copper-based electrocatalyst with controllable copper-oxygen coordination and anti-reconstruction, and the copper-based electrocatalyst is prepared by adopting the preparation method of the copper-based electrocatalyst with controllable copper-oxygen coordination and anti-reconstruction.

[0058] Specifically, the copper-oxygen coordination number of the copper-based electrocatalyst in the specific embodiment of the present invention is 1 to 5 (such as any value within the range of 1, 1.5, 2.0, 2.5, 3.0, 35., 4.0, 4.5, 5, etc.).

[0059] The present invention also provides an application of a copper-based electrocatalyst with controllable copper-oxygen coordination and resistance to reconstruction, and an application of the copper-based electrocatalyst in the carbon dioxide electroreduction reaction, wherein the copper-based electrocatalyst is prepared by adopting the above-mentioned preparation method of the copper-based electrocatalyst with controllable copper-oxygen coordination and resistance to reconstruction.

[0060] As an example, the reaction time in the carbon dioxide electroreduction reaction is 0.5 to 72 hours.

[0061] Specifically, the reaction time in the carbon dioxide electro-reduction reaction may include values ​​within any range such as 0.5 h, 1 h, 6 h, 12 h, 24 h, 48 h, 60 h, 66 h, and 72 h.

[0062] Preferably, the reaction time is 1 to 7 h (eg, 1 h, 2 h, 4 h, 6 h, 7 h, etc.).

[0063] As an example, the applied voltage for the carbon dioxide electroreduction reaction is -0.5 to -2.0 V vs. RHE.

[0064] Specifically, the applied voltage for the carbon dioxide electroreduction reaction may include values ​​within any range, such as -0.5 V vs. RHE, -1.0 V vs. RHE, -1.5 V vs. RHE, and -2.0 V vs. RHE.

[0065] Preferably, the applied voltage is -1.2 to -1.6 V vs. RHE (eg, -1.2 V vs. RHE, -1.3 V vs. RHE, -1.4 V vs. RHE, -1.5 V vs. RHE, -1.6 V vs. RHE).

[0066] As an example, the electrolyte in the carbon dioxide electro-reduction reaction is one of 0.1~1M (such as 0.1M, 0.3M, 0.5M, 0.7M, 1M, etc.) KHCO3, 0.1~1M (such as 0.1M, 0.3M, 0.5M, 0.7M, 1M, etc.) NaHCO3, 0.1~1M (such as 0.1M, 0.3M, 0.5M, 0.7M, 1M, etc.) KOH, and 0.1~1M (such as 0.1M, 0.3M, 0.5M, 0.7M, 1M, etc.) NaOH.

[0067] In order to better understand the copper-oxygen coordination controllable and reconstruction-resistant copper-based electrocatalyst, preparation method and application thereof in the present invention, the copper-oxygen coordination controllable and reconstruction-resistant copper-based electrocatalyst, preparation method and application thereof in the present invention are described below with reference to specific embodiments. It should be noted that these embodiments are merely descriptive and do not limit the present invention in any way.

[0068] Example 1

[0069] This embodiment provides a method for preparing a copper-based electrocatalyst with controllable copper-oxygen coordination and anti-reconstruction, and the preparation method comprises the following steps:

[0070] S1. Prepare CuO precursor (one-dimensional CuO nanowire precursor) by direct precipitation method;

[0071] The preparation method of the one-dimensional CuO nanowire precursor is as follows: 30 mL of 0.3 M NaOH solution is added dropwise into 30 mL of 0.15 M CuCl2·2H2O solution, stirred at room temperature for a certain period of time, filtered and washed to obtain blue Cu(OH)2 nanowires, and finally the Cu(OH)2 nanowires are placed in a muffle furnace at 2°C min -1 The temperature was raised to 200°C and maintained for 2 h to obtain a CuO precursor (one-dimensional CuO nanowire precursor);

[0072] S2, the CuO precursor was mixed with 0.5wt.% Nafion to form a mixed solution, and then the mixed solution was dropwise coated on the surface of the substrate electrode (carbon paper), and vacuum dried at 40°C for 12h to obtain a loading of 0.5mg cm -2 A CuO precursor electrode loaded with a CuO precursor;

[0073] S3. At room temperature and pressure, place the CuO precursor electrode in the first electrolyte (0.1 M phosphate buffer solution (pH = 7.0) and 0.05 M p-phenylenediamine solution), set the voltage range to -0.4 to 0.7 V, scan 20 times, and scan speed to 5 mVs -1 , poly(p-phenylenediamine) was modified on the surface of the CuO precursor electrode by cyclic voltammetry, and after modification, the electrode was placed in ultrapure water for ultrasonic cleaning for 30 seconds to obtain a modified electrode;

[0074] S4. At room temperature and pressure, the modified electrode was placed in the second electrolyte (0.1M KHCO3), and the CuO precursor was in situ reduced at -1.5V vs RHE for 1.5h using the constant voltage method to obtain a copper-based electrocatalyst with controllable copper-oxygen coordination and anti-reconstruction (one-dimensional OD-Cu catalyst). The structure of the one-dimensional OD-Cu catalyst is consistent with that of the CuO precursor. The characterization results of X-ray absorption fine structure spectroscopy (XAFS) showed that its Cu-O coordination number was 4.7.

[0075] See also Figure 1 and Figure 2 They are respectively the SEM images of the CuO precursor prepared in this embodiment and the copper-based electrocatalyst (one-dimensional OD-Cu catalyst) prepared. It can be seen from the figure that the CuO precursor and the copper-based electrocatalyst have obvious nanowire morphology characteristics, indicating that the CuO precursor in Example 1 and the corresponding copper-based catalyst prepared have good anti-reconstruction ability, and the nanowire morphology characteristics of the CuO precursor are well preserved. This embodiment also provides an application of a copper-oxygen coordination controllable and anti-reconstruction copper-based electrocatalyst in the carbon dioxide electroreduction reaction. The copper-based electrocatalyst prepared in this embodiment is used as a catalyst. At room temperature, in a neutral buffer solution, a constant potential electrolysis method is used to reduce CO2, the applied voltage is -1.2V vs RHE, the reaction time is 1.5h, and the electrolyte is 0.5M KHCO3, generating multi-carbon products (ethanol, ethylene and propane and other products). According to performance testing, the total Faraday efficiency of the multi-carbon product reaches 77%, and the stability is good, with good catalytic effect.

[0076] Example 2

[0077] The present embodiment provides a method for preparing a copper-based electrocatalyst with controllable copper-oxygen coordination and anti-reconstruction. The difference between the preparation method and the method in Example 1 is that: in step S1, a CuO precursor (two-dimensional CuO nanosheet) is prepared by a hydrothermal synthesis method; the preparation method of the CuO precursor by a hydrothermal synthesis method specifically comprises: adding 30 mL of a 0.3M NaOH solution dropwise to 30 mL of a 0.15M CuCl2·2H2O solution, stirring evenly at room temperature, transferring the solution to a hydrothermal reactor, performing a hydrothermal reaction at 120°C for 12 hours, filtering and washing the precipitate to obtain a two-dimensional CuO nanosheet;

[0078] Other methods and steps are the same as those in Example 1 and will not be described again. The structure of the prepared copper-based electrocatalyst (two-dimensional OD-Cu catalyst) is consistent with that of the CuO precursor, and its Cu-O coordination number is 2.3.

[0079] This embodiment also provides an application of a copper-based electrocatalyst with controllable copper-oxygen coordination and anti-reconstruction in a carbon dioxide electroreduction reaction. The copper-based electrocatalyst prepared in this embodiment is used as a catalyst, and the other steps are the same as those in Example 1, which will not be repeated here. According to performance testing, the total Faraday efficiency of the multi-carbon product reaches 65.5%, and the stability is good, and it has a high CO2 electrocatalytic reduction ability.

[0080] Example 3

[0081] The present embodiment provides a method for preparing a copper-based electrocatalyst with controllable copper-oxygen coordination and anti-reconstruction. The difference between the preparation method and the one in Example 1 is that: in step S1, a CuO precursor (three-dimensional CuO nanoflower) is prepared by a precipitation conversion method; the preparation method of the CuO precursor prepared by the precipitation conversion method specifically comprises: adding 3 mL of ammonia water (25% to 28%) to 30 mL of a 0.06 M copper acetate solution, stirring evenly, and then adding 20 mL of a 0.075 M sodium carbonate solution, and then placing the mixed solution in a conical flask, placing it in a water bath at 95° C. for 2 hours, filtering, washing, and drying to obtain a three-dimensional CuO nanoflower;

[0082] Other methods and steps are the same as those in Example 1 and will not be described again. The structure of the prepared copper-based electrocatalyst (three-dimensional OD-Cu catalyst) is consistent with that of the CuO precursor, and its Cu-O coordination number is 1.7.

[0083] This embodiment also provides an application of a copper-based electrocatalyst with controllable copper-oxygen coordination and anti-reconstruction in a carbon dioxide electroreduction reaction. The copper-based electrocatalyst prepared in this embodiment is used as a catalyst, and the other steps are the same as those in Example 1, which will not be repeated here. According to performance testing, the total Faraday efficiency of the multi-carbon product reaches 52.1%, and the stability is good, and it has a high CO2 electrocatalytic reduction ability.

[0084] Example 4

[0085] This embodiment provides a method for preparing a copper-based electrocatalyst with controllable copper-oxygen coordination and anti-reconstruction, and the difference between the preparation method and the method in Example 1 is that the substrate electrode in step S2 is carbon cloth; the other methods and steps are the same as those in Example 1, and are not repeated here. The structure of the prepared copper-based electrocatalyst is consistent with that of the CuO precursor, and its Cu-O coordination number is 4.2.

[0086] This embodiment also provides an application of a copper-based electrocatalyst with controllable copper-oxygen coordination and anti-reconstruction in a carbon dioxide electroreduction reaction. The copper-based electrocatalyst prepared in this embodiment is used as a catalyst, and the other steps are the same as those in Example 1, which will not be repeated here. According to performance testing, the total Faraday efficiency of the multi-carbon product reaches 73.2%, and the stability is good, and it has a high CO2 electrocatalytic reduction ability.

[0087] Example 5

[0088] This embodiment provides a method for preparing a copper-based electrocatalyst with controllable copper-oxygen coordination and anti-reconstruction. The difference between the preparation method and the method in Example 1 is that the loading amount of the CuO precursor electrode loaded with the CuO precursor obtained in step S2 is 1 mg cm -2 The other methods and steps are the same as those in Example 1 and will not be described in detail. The structure of the obtained copper-based electrocatalyst is consistent with that of the CuO precursor, and its Cu-O coordination number is 3.8.

[0089] This embodiment also provides an application of a copper-based electrocatalyst with controllable copper-oxygen coordination and anti-reconstruction in a carbon dioxide electroreduction reaction. The copper-based electrocatalyst prepared in this embodiment is used as a catalyst, and the other steps are the same as those in Example 1, which will not be repeated here. According to performance testing, the total Faraday efficiency of the multi-carbon product reaches 68.9%, and the stability is good, and it has a high CO2 electrocatalytic reduction ability.

[0090] Example 6

[0091] This embodiment provides a method for preparing a copper-based electrocatalyst with controllable copper-oxygen coordination and anti-reconstruction, and the difference between the preparation method and the method in Example 1 is that the first electrolyte in step S3 is composed of 0.01M phosphate buffer solution (pH=7.0) and 0.1M o-phenylenediamine; the other methods and steps are the same as those in Example 1, and are not repeated here. The structure of the prepared copper-based electrocatalyst is consistent with the CuO precursor, and its Cu-O coordination number is 3.1.

[0092] This embodiment also provides an application of a copper-based electrocatalyst with controllable copper-oxygen coordination and anti-reconstruction in a carbon dioxide electroreduction reaction. The copper-based electrocatalyst prepared in this embodiment is used as a catalyst, and the other steps are the same as those in Example 1, which will not be repeated here. According to performance testing, the total Faraday efficiency of the multi-carbon product reaches 60.3%, and the stability is good, and it has a high CO2 electrocatalytic reduction ability.

[0093] Example 7

[0094] This embodiment provides a method for preparing a copper-based electrocatalyst with controllable copper-oxygen coordination and anti-reconstruction. The difference between the preparation method and the method in Example 1 is that the conditions of the cyclic voltammetry in step S3 are to set the voltage range to -0.3 to 0.7 V, the number of scans to 50, and the scan rate to 20 mVs -1 The other methods and steps are the same as those in Example 1 and will not be described in detail. The structure of the obtained copper-based electrocatalyst is consistent with that of the CuO precursor, and its Cu-O coordination number is 3.4.

[0095] This embodiment also provides an application of a copper-based electrocatalyst with controllable copper-oxygen coordination and anti-reconstruction in a carbon dioxide electroreduction reaction. The copper-based electrocatalyst prepared in this embodiment is used as a catalyst, and the other steps are the same as those in Example 1, which will not be repeated here. According to performance testing, the total Faraday efficiency of the multi-carbon product reaches 64.4%, and the stability is good, and it has a high CO2 electrocatalytic reduction ability.

[0096] Example 8

[0097] This embodiment provides a method for preparing a copper-based electrocatalyst with controllable copper-oxygen coordination and anti-reconstruction, and the difference between the preparation method and the method in Example 1 is that the second electrolyte in step S4 is 0.1M NaHCO3; the other methods and steps are the same as those in Example 1, and are not repeated here. The structure of the prepared copper-based electrocatalyst is consistent with that of the CuO precursor, and its Cu-O coordination number is 3.2.

[0098] This embodiment also provides an application of a copper-based electrocatalyst with controllable copper-oxygen coordination and anti-reconstruction in a carbon dioxide electroreduction reaction. The copper-based electrocatalyst prepared in this embodiment is used as a catalyst, and the other steps are the same as those in Example 1, which will not be repeated here. According to performance testing, the total Faraday efficiency of the multi-carbon product reaches 62.3%, and the stability is good, and it has a high CO2 electrocatalytic reduction ability.

[0099] Example 9

[0100] This embodiment provides a method for preparing a copper-based electrocatalyst with controllable copper-oxygen coordination and anti-reconstruction, and the difference between the preparation method and the method in Example 1 is that in step S4, a constant voltage method is used to in-situ reduce the CuO precursor at -2.0V vs RHE for 1h; other methods and steps are the same as those in Example 1, and are not repeated here. The structure of the prepared copper-based electrocatalyst is consistent with that of the CuO precursor, and its Cu-O coordination number is 3.3.

[0101] This embodiment also provides an application of a copper-based electrocatalyst with controllable copper-oxygen coordination and anti-reconstruction in a carbon dioxide electroreduction reaction. The copper-based electrocatalyst prepared in this embodiment is used as a catalyst, and the other steps are the same as those in Example 1, which will not be repeated here. According to performance testing, the total Faraday efficiency of the multi-carbon product reaches 63.8%, and the stability is good, and it has a high CO2 electrocatalytic reduction ability.

[0102] Example 10

[0103] This embodiment provides a method for preparing a copper-based electrocatalyst with controllable copper-oxygen coordination and anti-reconstruction, and the difference between the preparation method and the method in Example 1 is that in step S4, a constant voltage method is used to in-situ reduce the CuO precursor at -1.2V vs RHE for 10 hours; other methods and steps are the same as those in Example 1, and are not repeated here. The structure of the prepared copper-based electrocatalyst is consistent with that of the CuO precursor, and its Cu-O coordination number is 3.6.

[0104] This embodiment also provides an application of a copper-based electrocatalyst with controllable copper-oxygen coordination and anti-reconstruction in a carbon dioxide electroreduction reaction. The copper-based electrocatalyst prepared in this embodiment is used as a catalyst, and the other steps are the same as those in Example 1, which will not be repeated here. According to performance testing, the total Faraday efficiency of the multi-carbon product reaches 65.1%, and the stability is good, and it has a high CO2 electrocatalytic reduction ability.

[0105] Embodiment 11

[0106] This embodiment provides a method for preparing a copper-based electrocatalyst with controllable copper-oxygen coordination and anti-reconstruction, and the difference between the preparation method and the method in Example 2 is that the substrate electrode in step S2 is a titanium sheet; the other methods and steps are the same as those in Example 2, and are not repeated here. The structure of the prepared copper-based electrocatalyst is consistent with that of the CuO precursor, and its Cu-O coordination number is 2.5.

[0107] This embodiment also provides an application of a copper-based electrocatalyst with controllable copper-oxygen coordination and anti-reconstruction in a carbon dioxide electroreduction reaction. The copper-based electrocatalyst prepared in this embodiment is used as a catalyst, and the other steps are the same as those in Example 1, which will not be repeated here. According to performance testing, the total Faraday efficiency of the multi-carbon product reaches 66.1%, and the stability is good, and it has a high CO2 electrocatalytic reduction ability.

[0108] Example 12

[0109] This embodiment provides a method for preparing a copper-based electrocatalyst with controllable copper-oxygen coordination and anti-reconstruction. The difference between the preparation method and the method in Example 2 is that the loading amount of the CuO precursor electrode loaded with the CuO precursor obtained in step S2 is 0.7 mg cm -2 The other methods and steps are the same as those in Example 2 and will not be described in detail. The structure of the obtained copper-based electrocatalyst is consistent with that of the CuO precursor, and its Cu-O coordination number is 2.1.

[0110] This embodiment also provides an application of a copper-based electrocatalyst with controllable copper-oxygen coordination and anti-reconstruction in a carbon dioxide electroreduction reaction. The copper-based electrocatalyst prepared in this embodiment is used as a catalyst, and the other steps are the same as those in Example 1, which will not be repeated here. According to performance testing, the total Faraday efficiency of the multi-carbon product reaches 61.0%, and the stability is good, and it has a high CO2 electrocatalytic reduction ability.

[0111] Example 13

[0112] This embodiment provides a method for preparing a copper-based electrocatalyst with controllable copper-oxygen coordination and anti-reconstruction, and the difference between the preparation method and the method in Example 2 is that the first electrolyte in step S3 is composed of 1M phosphate buffer solution (pH=7.0) and 1M m-phenylenediamine; the other methods and steps are the same as those in Example 2, and are not repeated here. The structure of the prepared copper-based electrocatalyst is consistent with the CuO precursor, and its Cu-O coordination number is 2.2.

[0113] This embodiment also provides an application of a copper-based electrocatalyst with controllable copper-oxygen coordination and anti-reconstruction in a carbon dioxide electroreduction reaction. The copper-based electrocatalyst prepared in this embodiment is used as a catalyst, and the other steps are the same as those in Example 1, which will not be repeated here. According to performance testing, the total Faraday efficiency of the multi-carbon product reaches 57.7%, and the stability is good, and it has a high CO2 electrocatalytic reduction ability.

[0114] Embodiment 14

[0115] This embodiment provides a method for preparing a copper-based electrocatalyst with controllable copper-oxygen coordination and anti-reconstruction, and the difference between the preparation method and the method in Example 2 is that the second electrolyte in step S4 is 1M KHCO3; the other methods and steps are the same as those in Example 2, and are not repeated here. The structure of the prepared copper-based electrocatalyst is consistent with that of the CuO precursor, and its Cu-O coordination number is 2.0.

[0116] This embodiment also provides an application of a copper-based electrocatalyst with controllable copper-oxygen coordination and anti-reconstruction in a carbon dioxide electroreduction reaction. The copper-based electrocatalyst prepared in this embodiment is used as a catalyst, and the other steps are the same as those in Example 1, which will not be repeated here. According to performance testing, the total Faraday efficiency of the multi-carbon product reaches 55.5%, and the stability is good, and it has a high CO2 electrocatalytic reduction ability.

[0117] Embodiment 15

[0118] This embodiment provides a method for preparing a copper-based electrocatalyst with controllable copper-oxygen coordination and anti-reconstruction. The difference between the preparation method and the method in Example 3 is that the conditions of the cyclic voltammetry in step S3 are to set the voltage range to -0.4 to 0.6 V, the number of scans to 100, and the scan rate to 100 mVs-1 The other methods and steps are the same as those in Example 3 and will not be described in detail. The structure of the obtained copper-based electrocatalyst is consistent with that of the CuO precursor, and its Cu-O coordination number is 1.5.

[0119] This embodiment also provides an application of a copper-based electrocatalyst with controllable copper-oxygen coordination and anti-reconstruction in a carbon dioxide electroreduction reaction. The copper-based electrocatalyst prepared in this embodiment is used as a catalyst, and the other steps are the same as those in Example 1, which will not be repeated here. According to performance testing, the total Faraday efficiency of the multi-carbon product reaches 51.8%, and the stability is good, and it has a high CO2 electrocatalytic reduction ability.

[0120] Example 16

[0121] This embodiment provides a method for preparing a copper-based electrocatalyst with controllable copper-oxygen coordination and anti-reconstruction, and the difference between the preparation method and that in Example 3 is that in step S4, a constant voltage method is used to in-situ reduce the CuO precursor at -1.6V vs RHE for 2.5h; other methods and steps are the same as those in Example 3, and are not repeated here. The structure of the prepared copper-based electrocatalyst is consistent with that of the CuO precursor, and its Cu-O coordination number is 1.5.

[0122] This embodiment also provides an application of a copper-based electrocatalyst with controllable copper-oxygen coordination and anti-reconstruction in a carbon dioxide electroreduction reaction. The copper-based electrocatalyst prepared in this embodiment is used as a catalyst, and the other steps are the same as those in Example 1, which will not be repeated here. According to performance testing, the total Faraday efficiency of the multi-carbon product reaches 50.8%, and the stability is good, and it has a high CO2 electrocatalytic reduction ability.

[0123] Comparative Example 1

[0124] This comparative example provides a method for preparing a copper-based electrocatalyst with controllable copper-oxygen coordination and anti-reconstruction, and the difference between the preparation method and the method in Example 1 is that step S3 is omitted; the other steps are the same as those in Example 1 and are not repeated here. The structure of the prepared copper-based electrocatalyst is quite different from that of the precursor, and its Cu-O coordination number is 1.3.

[0125] The copper-based electrocatalyst prepared in this comparative example was used as a catalyst in the carbon dioxide electroreduction reaction, and the other steps were the same as those in Example 1. According to the performance test, the total Faraday efficiency of the multi-carbon product was only 49.8%.

[0126] It can be seen from the above Examples 1 to 16 and Comparative Example 1 that the main factors affecting the Cu-O coordination number of the prepared oxide-derived copper catalyst (OD-Cu) include the dimensional characteristics of the CuO precursor and the modification of polyphenylene diamine during the in-situ reconstruction process. The difference in dimension means a significant difference in specific surface area. The low-dimensional structure has a large specific surface area, which leads to a high surface energy of the catalyst and a strong oxygen affinity, and thus the Cu in the obtained OD-Cu is δ+ More types, stronger Cu-O coordination ability. Polyphenylenediamine, as a thickness-limited electropolymer, can be evenly covered on the surface of the CuO precursor, but the thickness is only a few nanometers. Its presence can stabilize the surface microenvironment of the CuO precursor during the electroreduction process, allowing the CuO precursor to maintain the stability of its microstructure during the reduction to OD-Cu; in addition, it can also prevent the oxidation of the generated OD-Cu; and then according to the preparation method of the present invention, a stable OD-Cu catalyst can be prepared according to the set copper-oxygen coordination target. Factors such as substrate materials, electropolymerization parameters of phenylenediamine, and in-situ electroreduction parameters of CuO will affect the Cu-O coordination number, but will not have a significant impact on the structure and catalytic stability of the final OD-Cu.

[0127] In summary, the present invention provides a method for preparing a copper-based electrocatalyst with high efficiency, controllable copper-oxygen coordination, low cost and anti-reconstruction, and adopts a method of in-situ reduction of a CuO precursor under a specific mesoscopic morphology to obtain an oxide-derived copper (OD-Cu) catalyst with controllable Cu-O coordination number and anti-reconstruction, the preparation method is simple, the result is controllable, and the prepared copper-based electrocatalyst has high electrocatalytic activity, high selectivity and high stability in the carbon dioxide electroreduction reaction; the copper-based electrocatalyst is applied to the electrocatalytic carbon dioxide reduction reaction, especially to the reaction of electrocatalytic carbon dioxide conversion to generate multi-carbon products, which can effectively solve the problem of low selectivity of C2+ products affected by copper-based catalysts in the prior art. The copper-based electrocatalyst in the present invention resists reconstruction in the electrochemical reduction reaction, and the copper-oxygen coordination number of the constructed catalyst is high. In the carbon dioxide electroreduction reaction at room temperature and pressure, the total Faraday efficiency of the generated multi-carbon products is as high as 77%, which has a very high application prospect. Therefore, the present invention effectively overcomes the various shortcomings in the prior art and has a high industrial utilization value.

[0128] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A method for preparing a copper-based electrocatalyst with controllable copper-oxygen coordination and anti-reconstruction, characterized in that: The preparation method comprises the following steps: S1. providing a CuO precursor; S2, mixing the CuO precursor with Nafion to form a mixed solution, and then applying the mixed solution to the surface of the base electrode to obtain a CuO precursor electrode loaded with the CuO precursor; S3, placing the CuO precursor electrode in a first electrolyte at room temperature and pressure, and modifying the surface of the CuO precursor electrode with polyphenylenediamine by cyclic voltammetry to obtain a modified electrode; S4. At room temperature and pressure, the modified electrode is placed in a second electrolyte, and a CuO precursor is in situ reduced by a constant voltage method to obtain a copper-based electrocatalyst with controllable copper-oxygen coordination and resistance to reconstruction.

2. The method for preparing a copper-based electrocatalyst with controllable copper-oxygen coordination and anti-reconstruction according to claim 1, characterized in that: Step S1 includes one or a combination of the following conditions: The preparation method of the CuO precursor is one of a direct precipitation method, a precipitation conversion method, and a hydrothermal synthesis method; The mesoscopic dimensional characteristics of the CuO precursor are one or a combination of zero-dimensional, one-dimensional, two-dimensional, and three-dimensional characteristics.

3. The method for preparing a copper-based electrocatalyst with controllable copper-oxygen coordination and anti-reconstruction according to claim 1, characterized in that: Step S2 includes one or a combination of the following conditions: The base electrode comprises one of carbon paper, carbon cloth and titanium sheet; On the electrode loaded with CuO precursor, the loading amount of CuO precursor on the substrate electrode is 0.1-2 mg cm -2 .

4. The method for preparing a copper-based electrocatalyst with controllable copper-oxygen coordination and anti-reconstruction according to claim 1, characterized in that: In step S3, the first electrolyte includes a mixture of 0.01-1M phosphate buffer solution and 0.01-1M phenylenediamine. The pH value of the phosphate buffer solution is 7.0; and the phenylenediamine is one or more of o-phenylenediamine, m-phenylenediamine, and p-phenylenediamine.

5. The method for preparing a copper-based electrocatalyst with controllable copper-oxygen coordination and anti-reconstruction according to claim 1, characterized in that: The voltage range of the cyclic voltammetry in step S3 is -0.4 to 0.7 V, the number of scans is 2 to 100, and the scan rate is 2 to 100 mVs -1 .

6. The method for preparing a copper-based electrocatalyst with controllable copper-oxygen coordination and anti-reconstruction according to claim 1, characterized in that: In step S4, the second electrolyte is one of 0.01-5M NaHCO3 and 0.01-5M KHCO3.

7. The method for preparing a copper-based electrocatalyst with controllable copper-oxygen coordination and anti-reconstruction according to claim 1, characterized in that: The voltage of the in-situ reduction in step S4 is -0.8 to -2.5 V vs RHE, and the application time of the in-situ reduction is 1 to 24 hours.

8. A copper-based electrocatalyst with controllable copper-oxygen coordination and anti-reconstruction, characterized in that: The copper-based electrocatalyst is prepared by the method for preparing a copper-based electrocatalyst with controllable copper-oxygen coordination and anti-reconstruction according to any one of claims 1 to 7.

9. Application of a copper-based electrocatalyst with controllable copper-oxygen coordination and anti-reconstruction, characterized in that: The application of the copper-based electrocatalyst in the carbon dioxide electroreduction reaction, wherein the copper-based electrocatalyst is prepared by the preparation method of the copper-oxygen coordination controllable and reconstruction-resistant copper-based electrocatalyst according to any of claims 1 to 7.

10. The use of the copper-based electrocatalyst with controllable copper-oxygen coordination and anti-reconstruction according to claim 9, characterized in that: Includes one or a combination of the following conditions: The reaction time of the carbon dioxide electroreduction reaction is 0.5 to 72 hours; The applied voltage of the carbon dioxide electroreduction reaction is -0.5 to -2.0 V vs. RHE; The electrolyte in the carbon dioxide electroreduction reaction is one of 0.1-1M KHCO3, 0.1-1M NaHCO3, 0.1-1M KOH, and 0.1-1M NaOH.

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