Method for realizing electrochemically controllable restructuring of copper oxide by adding cobalt ions and application thereof

Abstract

The present application belongs to the technical field of electrochemical catalysis, and relates to a method for realizing electrochemical controllable restructuring of copper oxide by adding cobalt ions, which comprises the following steps: in a three-electrode system, taking a platinum sheet as a counter electrode, a mercury / mercury oxide electrode (Hg / HgO) as a reference electrode, and copper oxide as a working electrode, and taking an alkaline solution as an electrolyte, performing LSV test on the copper oxide in an H-type electrolytic cell until the curve is stable, wherein the copper oxide is prepared by pyrolysis of a copper oxide precursor prepared by a cyclic voltammetry method; adding a cobalt ion solution to the anode of the electrolytic cell, standing, and performing LSV test on the copper oxide until it is stable. By adding trace cobalt ions to the electrolyte, the catalytic performance of the copper oxide can be significantly improved, and by adjusting the concentration of the added cobalt ions, the copper oxide can grow into nanowires of different sizes, so as to realize electrochemical controllable restructuring of the copper oxide. The nanowires on the surface of the catalyst not only increase the contact area of the catalyst with the electrolyte, but also significantly reduce the charge transfer resistance, which is conducive to reducing the overpotential in the actual catalytic process.

Description

Technical Field

[0001] This invention belongs to the field of electrochemical catalysis technology, and relates to catalyst reconstruction, particularly to a method for achieving electrochemically controllable reconstruction of copper oxide by adding cobalt ions and its application. Background Technology

[0002] With technological advancements and industrial progress, the extensive use of fossil fuels is leading to their continuous depletion, ultimately threatening reserves. Therefore, seeking new energy sources to replace fossil fuels is crucial. Hydrogen, a secondary energy source that can be produced using clean energy sources such as solar and wind power, boasts high energy density and ease of storage, thus attracting widespread attention. Among these, water electrolysis for hydrogen production is a mature technology with a simple process and high gas purity, making it a currently viable method for hydrogen production that can be integrated with renewable energy sources. Water electrolysis for hydrogen production involves two half-reactions: the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER). The OER, occurring at the anode, exhibits slow kinetics and a large overpotential, limiting the large-scale application of water electrolysis. Therefore, seeking high-performance catalysts to reduce the OER overpotential is imperative.

[0003] As research has progressed, transition metal-based catalysts have been found to offer excellent performance and low cost. While copper oxide has been extensively studied as an OER catalyst, its performance is not outstanding compared to other transition metals, making it unsuitable for industrial production. Therefore, improving the OER catalytic performance of copper oxide is crucial.

[0004] In electrochemical processes, the surface sites of electrocatalysts exhibit dynamic characteristics, capable of triggering remodeling phenomena. Particularly in OER (Organic Emission Reduction), remodeling connects the electrocatalyst surface with the active sites involved in the reaction. Surface remodeling can also modulate electrocatalyst behaviors such as adsorption, activation, and desorption, thereby influencing OER performance. Based on this, increasing research indicates that surface remodeling engineering is an effective strategy for improving the catalytic performance of OER electrocatalysts. Summary of the Invention

[0005] To address the shortcomings of the existing technology, the purpose of this invention is to disclose a method for achieving electrochemically controllable reconfiguration of copper oxide by adding cobalt ions.

[0006] Technical solution

[0007] A method for electrochemically controllable reconfiguration of copper oxide by adding cobalt ions includes the following steps:

[0008] A. In the three-electrode system, a platinum sheet is used as the counter electrode, a mercury / mercury oxide electrode (Hg / HgO) is used as the reference electrode, and copper oxide is used as the working electrode. The electrolyte concentration is 0.5–1.0 mol·L⁻¹. -1 The alkaline solution was used to perform LSV testing on copper oxide in an H-type electrolytic cell at a scan rate of 0.005 V·s. -1The process continues until the curve stabilizes. The copper oxide is prepared by cyclic voltammetry to obtain a copper oxide precursor, which is then pyrolyzed.

[0009] B. Add cobalt ion solution to the anode of the electrolytic cell, let it stand, and perform LSV testing on copper oxide at a scan rate of 0.005 V·s. -1 until the curve stabilizes.

[0010] In a preferred embodiment of the present invention, the alkaline solution in step A is a potassium hydroxide or sodium hydroxide solution, preferably 1.0 mol·L⁻¹. -1 A potassium hydroxide solution.

[0011] In a preferred embodiment of the present invention, the copper oxide described in step A is prepared by a method comprising: first, placing cut carbon paper successively in acetone and ethanol for ultrasonication; then washing with deionized water; and finally using the carbon paper as a catalyst support; using 0.5 mol·L⁻¹ -1 The copper ion solution is used as the electrolyte, and the copper ion solution contains 0.05~0.1 mol·L⁻¹ -1 A copper oxide precursor was prepared by cyclic voltammetry using sodium nitrate or potassium nitrate, a carbon rod as the counter electrode, an Ag / AgCl electrode as the reference electrode, and carbon paper as the working electrode. The prepared copper oxide precursor was then subjected to cyclic voltammetry at 10 °C·min. -1 The temperature is increased to 400℃ at a certain rate, held for 60 minutes, and then naturally cooled to room temperature to obtain the product.

[0012] Furthermore, the copper ion solution is a solution of copper nitrate, copper sulfate, copper chloride, etc., preferably a copper nitrate solution.

[0013] Furthermore, the copper ion solution contains 0.05 mol·L⁻¹ -1 Potassium nitrate.

[0014] Furthermore, the cyclic voltammetry test range is -1.2 to -1.0 V, and the scan rate is 0.01 V·s. -1 The number of cycles is 24.

[0015] In a preferred embodiment of the present invention, the cobalt ion solution in step B is a solution of cobalt nitrate, cobalt sulfate, cobalt chloride, etc., with cobalt nitrate solution being preferred.

[0016] In a preferred embodiment of the present invention, the concentration of cobalt ions in the anolyte in step B is 6 × 10⁻⁶. -6 ~6×10 -4 mol·L -1 .

[0017] The second objective of this invention is to apply it to improve the catalytic performance of the oxygen evolution reaction of copper oxide.

[0018] Electrochemical performance testing and structural reconstruction experiments of copper oxide:

[0019] a. In an H-type electrolytic cell, a three-electrode system is used, with a platinum sheet as the counter electrode, a mercury / mercury oxide electrode (Hg / HgO) as the reference electrode, and copper oxide as the working electrode, at 1.0 mol·L⁻¹. -1 The electrochemical performance of copper oxide in KOH electrolyte was tested using linear sweep voltammetry (LSV) at a scan rate of 0.005 V·s. -1 Continue until the LSV curve stabilizes;

[0020] b. Add a total of 60 μL of cobalt ion solution of different concentrations to the anode of the H-type electrolytic cell in three separate additions. Perform LSV testing on copper oxide after each addition until the curve stabilizes.

[0021] Adding cobalt ions to the electrolyte can not only improve the catalytic performance of copper oxide, but also change the structure of copper oxide from particulate to nanowire of different sizes by adding different concentrations of cobalt ions, thereby achieving electrochemically controllable reconstruction of copper oxide and thus improving the OER catalytic performance of copper oxide.

[0022] Beneficial effects

[0023] This invention is simple to operate. By adding trace amounts of cobalt ions to the electrolyte, the catalytic performance of copper oxide can be significantly improved. Adjusting the concentration of added cobalt ions allows for the growth of nanowires of different sizes from the copper oxide, thereby achieving electrochemically controllable reconstruction of copper oxide. The nanowires on the catalyst surface not only increase the contact area with the electrolyte but also significantly reduce the charge transfer resistance, which is beneficial for reducing overpotential in actual catalytic processes. This invention exhibits good reproducibility, uses inexpensive and non-toxic reaction materials, and has significant guiding significance for industrial water electrolysis. Attached Figure Description

[0024] Figure 1 Scanning electron microscope (SEM) images of copper oxide: (a) is a SEM image of copper oxide, (b) is a SEM image of copper oxide in Example 1, (c) is a SEM image of copper oxide in Example 2, and (d) is a SEM image of copper oxide in Example 3.

[0025] Figure 2 X-ray diffraction (XRD) pattern of copper oxide.

[0026] Figure 3 Linear sweep voltammetry (LSV) curves in the copper oxide electrolysis of water reaction.

[0027] Figure 4 Electrochemical impedance spectroscopy (EIS) of copper oxide. Detailed Implementation

[0028] The present invention will be described in detail below with reference to embodiments, so that those skilled in the art can better understand the present invention, but the present invention is not limited to the following embodiments.

[0029] Example 1

[0030] A method for electrochemically controllable reconfiguration of copper oxide by adding cobalt ions includes the following steps:

[0031] (1) Add 30 mL of 0.5 mol·L⁻¹ to a single-hole electrolytic cell. -1 Copper nitrate solution (containing 0.05 mol·L⁻¹) -1 Potassium nitrate), with a carbon rod as the counter electrode, Ag / AgCl as the reference electrode, and carbon paper as the working electrode, was used to prepare copper oxide precursor by cyclic voltammetry;

[0032] (2) The obtained copper oxide precursor was subjected to a temperature of 10 °C·min. -1 The temperature was increased to 400℃ at a heating rate and held for 60 minutes, then naturally cooled to room temperature to obtain copper oxide.

[0033] (3) In the H-type electrolytic cell, a three-electrode system was adopted, with a platinum sheet as the counter electrode, Hg / HgO as the reference electrode, and copper oxide as the working electrode. The electrolyte was prepared in 50 mL of 1.0 mol·L⁻¹ solution. -1 The electrochemical performance of copper oxide in KOH electrolyte was tested using linear sweep voltammetry at a scan rate of 0.005 V·s. -1 until the LSV curve stabilizes;

[0034] (4) Add 60 μL of 0.5 mol·L⁻¹ solution dropwise to the anode of the H-type electrolytic cell in three portions. -1 The copper oxide was subjected to LSV testing after stirring and standing for 1 minute in a cobalt nitrate solution until the curve stabilized.

[0035] After the prepared copper oxide sample stabilized under scanning tests, 60 μL of 0.5 mol·L⁻¹ solution was added dropwise. -1 The performance of copper oxide was improved by adding 60 μL of cobalt nitrate solution. Analysis showed that at a reversible hydrogen potential of 2.2 V, adding 0.5 mol·L⁻¹ of cobalt nitrate solution to the electrolyte improved the performance. -1 After using cobalt nitrate solution, the electrolytic water performance of copper oxide improved by 48.5%.

[0036] Figure 1 SEM images of the prepared copper oxide and copper oxide with added cobalt ions show that the prepared copper oxide covers the surface of the carbon paper in the form of irregular particles, while the morphology of the copper oxide changes to nanowires after the addition of cobalt ions.

[0037] Figure 2The XRD pattern of the prepared copper oxide material shows that the position and intensity of the diffraction peaks are consistent with the standard JCPDS-PDF card.

[0038] Figure 3 The measured LSV curves show that the performance of copper oxide is improved after the addition of cobalt ions.

[0039] Figure 4 The measured EIS diagram shows that the charge transfer resistance of copper oxide decreased after the addition of cobalt ions.

[0040] Once the prepared copper oxide has stabilized, a trace amount of 0.5 mol·L⁻¹ is added to the electrolyte solution. -1 The LSV curves show that the addition of cobalt nitrate solution significantly improved the catalytic performance of copper oxide. Analysis revealed that at a reversible hydrogen potential of 2.2 V, the addition of cobalt nitrate solution to the electrolyte solution improved the water electrolysis performance of copper oxide by 48.5%, and the morphology of the copper oxide changed from particulate to nanowire-like, with an average nanowire length of approximately 2.4 μm.

[0041] Example 2

[0042] A method for electrochemically controllable reconfiguration of copper oxide by adding cobalt ions includes the following steps:

[0043] (1) Add 30 mL of 0.5 mol·L⁻¹ to a single-hole electrolytic cell. -1 Copper nitrate solution (containing 0.05 mol·L⁻¹) -1 Potassium nitrate), with a carbon rod as the counter electrode, Ag / AgCl as the reference electrode, and carbon paper as the working electrode, was used to prepare copper oxide precursor by cyclic voltammetry;

[0044] (2) The obtained copper oxide precursor was subjected to a temperature of 10 °C·min. -1 The temperature is increased to 400℃ at a heating rate and held for 60 minutes, then naturally cooled to room temperature to obtain copper oxide.

[0045] (3) In the H-type electrolytic cell, a three-electrode system is adopted, with a platinum sheet as the counter electrode, Hg / HgO as the reference electrode, and copper oxide as the working electrode, in 50 mL of 1 mol·L⁻¹ electrolyte. -1 The electrochemical performance of copper oxide in KOH electrolyte was tested using linear sweep voltammetry at a scan rate of 0.005 V·s. -1 until the LSV curve stabilizes;

[0046] (4) Add 60 μL of 0.05 mol·L⁻¹ solution dropwise to the anode of the H-type electrolytic cell in three portions. -1 The copper oxide was subjected to LSV testing after stirring and standing for 1 minute in a cobalt nitrate solution until the curve stabilized.

[0047] After the prepared copper oxide has stabilized, a trace amount of 0.05 mol·L⁻¹ is added to the electrolyte solution. -1 The LSV curves show that the addition of cobalt nitrate solution significantly improved the catalytic performance of copper oxide. Analysis revealed that at a reversible hydrogen potential of 2.2 V, the addition of cobalt nitrate solution to the electrolyte solution improved the water electrolysis performance of copper oxide by 24.9%, and the morphology of the copper oxide changed from particulate to nanowire-like, with an average nanowire length of approximately 2.2 μm.

[0048] Example 3

[0049] A method for electrochemically controllable reconfiguration of copper oxide by adding cobalt ions includes the following steps:

[0050] (1) Add 30 mL of 0.5 mol·L⁻¹ to a single-hole electrolytic cell. -1 Copper nitrate solution (containing 0.05 mol·L⁻¹) -1 Potassium nitrate), with a carbon rod as the counter electrode, Ag / AgCl as the reference electrode, and carbon paper as the working electrode, was used to prepare copper oxide precursor by cyclic voltammetry;

[0051] (2) The obtained copper oxide precursor was subjected to a temperature of 10 °C·min. -1 The temperature is increased to 400 °C at a heating rate and held for 60 min, then naturally cooled to room temperature to obtain copper oxide.

[0052] (3) In the H-type electrolytic cell, a three-electrode system was adopted, with a platinum sheet as the counter electrode, Hg / HgO as the reference electrode, and copper oxide as the working electrode. The electrolyte was prepared in 50 mL of 1.0 mol·L⁻¹ solution. -1 The electrochemical performance of copper oxide in KOH electrolyte was tested using linear sweep voltammetry at a scan rate of 0.005 V·s. -1 until the LSV curve stabilizes;

[0053] (4) Add 60 μL of 0.005 mol·L⁻¹ solution dropwise to the anode of the H-type electrolytic cell in three portions. -1 The copper oxide was subjected to LSV testing after stirring and standing for 1 minute in a cobalt nitrate solution until the curve stabilized.

[0054] After the prepared copper oxide has stabilized, a trace amount of 0.005 mol·L⁻¹ is added to the electrolyte solution. -1The LSV curves show that the addition of cobalt nitrate solution significantly improved the catalytic performance of copper oxide. Analysis revealed that at a reversible hydrogen potential of 2.2 V, the addition of cobalt nitrate solution to the electrolyte solution improved the water electrolysis performance of copper oxide by 15.2%, and the morphology of the copper oxide changed from particulate to nanowire-like, with an average nanowire length of approximately 1.5 μm.

[0055] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made using the present invention specification, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A method for achieving electrochemically controllable reconfiguration of copper oxide by adding cobalt ions, characterized in that, Includes the following steps: A. In the three-electrode system, a platinum sheet is used as the counter electrode, a mercury / mercury oxide electrode as the reference electrode, and copper oxide as the working electrode. The electrolyte concentration is 0.5–1.0 mol·L⁻¹. -1 The alkaline solution was used to perform LSV testing on copper oxide in an H-type electrolytic cell at a scan rate of 0.005 V·s. -1 The process continues until the curve stabilizes. The copper oxide is prepared by cyclic voltammetry to obtain a copper oxide precursor, which is then pyrolyzed. B. Add cobalt ion solution to the anode of the electrolytic cell, allow to stand, and perform LSV testing on copper oxide at a scan rate of 0.005 V·s. -1 until the curve stabilizes.

2. The method for electrochemically controllable reconfiguration of copper oxide by adding cobalt ions according to claim 1, characterized in that: The alkaline solution mentioned in step A is a potassium hydroxide or sodium hydroxide solution.

3. The method for electrochemically controllable reconfiguration of copper oxide by adding cobalt ions according to claim 1, characterized in that: The alkaline solution mentioned in step A is 1.0 mol·L⁻¹. -1 A potassium hydroxide solution.

4. The method for electrochemically controllable reconfiguration of copper oxide by adding cobalt ions according to claim 1, characterized in that, The copper oxide described in step A is prepared by: first, placing cut carbon paper successively in acetone and ethanol for ultrasonic treatment; then washing with deionized water; the carbon paper is used as a catalyst support; and then... -1 The copper ion solution is used as the electrolyte, and the copper ion solution contains 0.05~0.1 mol·L⁻¹ -1 A copper oxide precursor was prepared by cyclic voltammetry using sodium nitrate or potassium nitrate, a carbon rod as the counter electrode, an Ag / AgCl electrode as the reference electrode, and carbon paper as the working electrode. The prepared copper oxide precursor was then subjected to cyclic voltammetry at 10 °C·min. -1 The temperature is increased to 400℃ at a certain rate, held for 60 minutes, and then naturally cooled to room temperature to obtain the product.

5. The method for electrochemically controllable reconfiguration of copper oxide by adding cobalt ions according to claim 4, characterized in that: The copper ion solution is a copper nitrate, copper sulfate, or copper chloride solution.

6. The method for electrochemically controllable reconfiguration of copper oxide by adding cobalt ions according to claim 4, characterized in that: The copper ion solution contains 0.05 mol·L⁻¹ -1 Potassium nitrate.

7. The method for electrochemically controllable reconfiguration of copper oxide by adding cobalt ions according to claim 4, characterized in that: The cyclic voltammetry test range is -1.2 to -1.0 V, and the scan rate is 0.01 V·s. -1 The number of cycles is 24.

8. The method for electrochemically controllable reconfiguration of copper oxide by adding cobalt ions according to claim 1, characterized in that: The cobalt ion solution mentioned in step B is a cobalt nitrate, cobalt sulfate, or cobalt chloride solution.

9. The method for electrochemically controllable reconfiguration of copper oxide by adding cobalt ions according to claim 1, characterized in that: In step B, the cobalt ion concentration in the anolyte is 6 × 10⁻⁶. -6 ~6×10 -4 mol·L -1 .

10. An application of the method as described in any one of claims 1-9, characterized in that: It was applied to improve the catalytic performance of the oxygen evolution reaction of copper oxide.

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