Copper-nickel-zinc ternary composite electrode, preparation method thereof and application of copper-nickel-zinc ternary composite electrode in electrocatalytic nitrate reduction synthesis of ammonia
The preparation of copper, nickel and zinc ternary composite electrodes through laser induction solves the problems of complex synthesis of traditional electrocatalysts and poor stability of electrode preparation, and achieves efficient preparation of high-performance electrocatalysts, which significantly improves the activity and ammonia production performance of electrocatalytic nitrate reduction reaction.
Patent Information
- Application Number
- CN202510387358.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-31
- Publication Date
- 2025-06-27
- Estimated Expiration
- Not applicable · inactive patent
AI Technical Summary
The controllable synthesis of traditional electrocatalysts is complex and time-consuming, and the electrode preparation method that relies on polymer binders is poor in stability, resulting in a decrease in activity and selectivity of electrocatalytic nitrate reduction reaction.
The copper-nickel-zinc ternary composite electrode was prepared by laser induction method, and the copper alloy sheet was engraved by pulsed laser scanning to form a high-performance electrocatalyst, which simplified the electrode preparation process and improved the preparation efficiency.
It realizes efficient preparation of high-performance electrocatalysts under normal temperature and pressure, significantly improves the activity and ammonia production performance of electrocatalytic nitrate reduction reaction, simplifies the electrode preparation process and reduces the use of harmful reagents and solvents.
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Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of electrocatalytic nitrate reduction, and specifically relates to a copper-nickel-zinc ternary composite electrode, a preparation method thereof, and an application thereof in electrocatalytic nitrate reduction for ammonia synthesis. Background Art
[0002] The electrocatalytic nitrate reduction reaction (NO3RR) for ammonia production involves competitive adsorption and conversion of multiple intermediate products, including a complex 8-electron transfer process between the electrode interface and various adsorbed substrates, accompanied by multiple 9-proton transfer reactions. In addition, too high or too low adsorption energy between the electrocatalyst and the intermediate products can easily lead to a decrease in the NO3RR activity or ammonia production selectivity of the electrocatalyst, resulting in limited ammonia Faraday efficiency and yield.
[0003] Through the rational design, preparation, and regulation of electrocatalysts (such as single-atom doping, surface defect regulation, crystal plane orientation, and crystal structure regulation), the adsorption energy and activation energy of intermediates can be optimized, thus significantly enhancing the kinetics of the electrocatalytic nitrate reduction reaction. However, the controllable synthesis of traditional electrocatalysts often requires complex multi-step reactions, long preparation times, and harsh preparation conditions (such as hydrothermal methods at high temperature and high pressure). In addition, the actual performance of the electrocatalytic nitrate reduction reaction largely depends on the immobilization and assembly strategy of the electrocatalyst at the current collector interface. The traditional electrode preparation method relying on polymer binders not only has poor stability and cumbersome operation, but also leads to a decrease in the conductivity of the electrode interface and the activity of the electrocatalytic nitrate reduction reaction. Therefore, exploring a simple and rapid preparation method for realizing high-performance electrocatalytic nitrate reduction reaction electrodes remains an important challenge. Summary of the Invention
[0004] The present invention provides a preparation method for a copper-nickel-zinc ternary composite electrode, comprising the following steps: scanning and engraving a cupronickel alloy sheet with a pulsed laser, and after the scanning is completed, obtaining a copper-nickel-zinc ternary composite electrode.
[0005] In the above preparation method, the cupronickel alloy sheet is cleaned with dilute hydrochloric acid before laser engraving to remove the surface oxide layer.
[0006] In the above preparation method, the laser scanning parameters are selected from: laser wavelength of 353 - 1064 nm, pulse frequency of 1 - 200 kHz, laser power of 10 - 30 W, scanning speed of 20 - 60 cm / s, DPI resolution of 800 - 1200, and laser scanning area of 1 - 100 cm 2 ; preferably: laser wavelength of 1064 nm, pulse frequency of 1.0 kHz, laser power of 15 W, scanning speed of 42 cm / s, DPI resolution of 1200, and laser scanning area of 1 cm 2 .
[0007] In the present invention, the cupronickel alloy sheet is one of ferronickel, manganese nickel, zinc nickel, and aluminum nickel; preferably zinc nickel.
[0008] The present invention provides a copper-nickel-zinc ternary composite electrode prepared by the above method.
[0009] The present invention provides the application of the above copper-nickel-zinc ternary composite electrode in electrocatalytic nitrate reduction for ammonia synthesis.
[0010] The present invention provides a method for electrocatalytic nitrate reduction for ammonia synthesis, comprising the following steps:
[0011] Using a platinum wire electrode as the counter electrode, an Ag / AgCl electrode as the reference electrode, and a copper-nickel-zinc ternary composite electrode as the working electrode; adopting an H-type electrolytic cell, separating the anode chamber and the cathode chamber with a proton exchange membrane, and filling an anode electrolyte solution and a cathode electrolyte solution respectively; inserting the working electrode and the reference electrode into the cathode chamber, and inserting the counter electrode into the anode chamber to form a three-electrode system; then setting the electrocatalytic reaction parameters and synthesizing ammonia by electrocatalytic nitrate reduction.
[0012] In the above method for electrocatalytic nitrate reduction for ammonia synthesis, the anode electrolyte solution is a salt solution without nitrate; the salt is selected from one or more of potassium sulfate, sodium sulfate, lithium sulfate, and cesium sulfate; the concentration of the salt solution is selected from 300-700 mM, preferably 500 mM.
[0013] In the above method for electrocatalytic nitrate reduction for ammonia synthesis, the cathode electrolyte solution is a mixed salt solution containing nitrate; the other salt in the mixed salt is selected from one or more of potassium sulfate, sodium sulfate, lithium sulfate, and cesium sulfate; the nitrate is selected from one or more of potassium nitrate, sodium nitrate, lithium nitrate, and cesium nitrate; in the mixed salt solution, the concentration of nitrate is selected from 50-150 mM, preferably 100 mM; the concentration of the other salt is selected from 100-1000 mM, preferably 500 mM.
[0014] In the above method for electrocatalytic nitrate reduction for ammonia synthesis, the electrocatalytic reaction parameters are selected from: the electrocatalytic potential is -0.6 to -1.0 V vs RHE, and the electrocatalytic temperature is 20 to 30 °C; preferably: the electrocatalytic potential is -0.8 V vs RHE, and the electrocatalytic temperature is 25 °C.
[0015] The beneficial effects of the present invention are:
[0016] The present invention uses a laser-induced method to prepare a copper-nickel-zinc ternary composite electrode. This method is a new preparation method for the copper-nickel-zinc ternary composite electrode, which can be completed in an atmospheric environment at normal temperature and pressure. It is a direct solid-phase conversion process, which greatly simplifies the electrode preparation process, improves the electrode preparation efficiency, and effectively reduces the use of harmful reagents and solvents. In addition, when using the laser-induced method to prepare the copper-nickel-zinc ternary composite electrode, the controllability is relatively strong. The electrode performance can be regulated and optimized by changing the laser scanning parameters, and the shape and size of the electrocatalyst generation area can be controlled in a patterned manner. The copper-nickel-zinc ternary composite electrode prepared by the laser-induced method described in the present invention has high electrocatalytic nitrate reduction reaction activity and excellent ammonia production performance, so it has important application value in the field of electrocatalytic nitrate reduction to produce ammonia.
[0017] In summary, the present invention has developed a new method for constructing a binder-free, self-supporting, and patterned electrocatalytic nitrate reduction electrode that can in-situ and synchronously generate a high-performance copper-nickel-zinc ternary composite electrocatalyst on the surface of a metal alloy sheet current collector. While simplifying the preparation process of the electrocatalytic nitrate reduction electrode, it improves the electrocatalytic nitrate reduction to ammonia efficiency and selectivity. Brief Description of the Drawings
[0018] Figure 1 is the laser-induced preparation process of the copper-nickel-zinc ternary composite electrode;
[0019] Figure 2 is the experimental result diagram of electrocatalytic nitrate reduction using the copper-nickel-zinc ternary composite electrode described in Example 1;
[0020] Figure 3 is the chronopotentiometry curve diagram of constant-potential electrocatalytic nitrate synthesis of ammonia using the copper-nickel-zinc ternary composite electrode described in Example 2;
[0021] Figure 4 is the standard curve diagram for detecting ammonia by colorimetry in Example 2;
[0022] Figure 5 is the absorbance curve diagram of the product detection of ammonia synthesis using the copper-nickel-zinc ternary composite electrode described in Example 2;
[0023] Figure 6 is the chronopotentiometry curve diagram of constant-potential electrocatalytic nitrate synthesis of ammonia using the copper-nickel-zinc ternary composite electrode described in Comparative Example 1;
[0024] Figure 7 is the standard curve diagram for detecting ammonia by colorimetry in Comparative Example 1;
[0025] Figure 8 is the chronopotentiometry curve diagram of constant-potential electrocatalytic nitrate synthesis of ammonia using the copper-nickel-zinc ternary composite electrode described in Comparative Example 1;
[0026] Figure 9 Chronopotentiometry curve of constant potential electrocatalytic synthesis of ammonia from nitrate using the copper-nickel-zinc ternary composite electrode described in Comparative Example 2;
[0027] Figure 10 Standard curve for colorimetric detection of ammonia in Comparative Example 2;
[0028] Figure 11 Chronopotentiometry curve of constant potential electrocatalytic synthesis of ammonia from nitrate using the copper-nickel-zinc ternary composite electrode described in Comparative Example 2. Specific embodiments
[0029] In the present invention, Figure 1 The laser-induced process of the copper-nickel-zinc ternary composite electrode is shown.
[0030] There are mainly two purposes for the laser induction: First, a metastable composite metal oxide layer is in-situ generated on the surface of the alloy sheet, such as a composite of metastable cuprous oxide, metastable nickel oxide, and metastable zinc oxide. During the electrocatalytic reduction process, the metastable metal oxide layer is partially reduced to metal, forming a metal-metal oxide composite electrocatalyst, such as a copper / metastable cuprous oxide composite electrocatalyst, which contains a large number of oxygen vacancy defects and greatly improves the electrocatalytic nitrate reduction activity. Second, the copper-nickel composite catalyst generated by laser induction greatly improves the roughness of the metal surface morphology and increases the specific surface area of the catalyst.
[0031] The laser-induced process is as follows:
[0032] When the laser scans a certain position on the metal sheet, the metal at this position can absorb the 1064 nm pulsed laser. After the metal absorbs the laser, local high temperature will be instantly generated at this position, and the temperature can reach above 1000 °C, triggering the plasma reaction between the metal surface and air to produce composite metal oxides. When the laser leaves this position, its local temperature drops rapidly, causing the rapid cooling of the metal oxide, so that a large number of vacancy defect sites are retained, forming a metastable composite metal oxide electrocatalyst.
[0033] The principle of electrocatalytic nitrate reduction is as follows:
[0034] Copper-based catalysts have excellent nitrate adsorption performance, so they can improve the substrate adsorption ability and nitrate deoxygenation ability; nickel-based catalysts have excellent hydrogen activation effect, so they can improve the nitrate hydrogenation process.
[0035] During the electrocatalytic nitrate reduction process of the copper-nickel composite electrocatalyst, nitrate is first adsorbed on the surface of the copper-based catalyst. With the help of the proton-coupled electron transfer process, the oxygen atom on nitrate combines with hydrogen ions in the solution to form water, and finally activated nitrogen atoms are generated, thus realizing the efficient electrocatalytic reduction and deoxygenation of nitrate. At the same time, hydrogen ions in the solution are adsorbed on the surface of the nickel-based electrocatalyst and reduced to activated hydrogen. With the help of the hydrogen atom transfer process, the activated hydrogen on the surface of the nickel-based catalyst combines with the activated nitrogen on the surface of the copper-based catalyst to complete the hydrogenation reaction process, thus realizing the efficient electrocatalytic hydrogenation reaction of nitrate and improving the efficiency of ammonia synthesis.
[0036] Other materials used in the present invention can be obtained through commercial channels unless otherwise specified. Other terms used in the present invention generally have the meanings commonly understood by those of ordinary skill in the art unless otherwise stated. The present invention will be described in further detail below with reference to specific examples and data. The following examples are only for illustrating the present invention and do not limit the scope of the present invention in any way.
[0037] Example 1
[0038] 1. Preparation of laser-induced copper-nickel-zinc ternary composite electrode
[0039] A copper-nickel-zinc ternary composite electrode was prepared using a cupronickel alloy sheet. The steps are as follows:
[0040] A cupronickel alloy sheet (nickel silver) with dimensions of 30*10*0.5 mm was placed in a dilute hydrochloric acid solution for cleaning to remove the surface oxide layer. The cleaned metal sheet was dried and placed in a laser engraving machine. The two sides of the cupronickel alloy sheet were scanned with a pulsed laser with a wavelength of 1064 nm. The specific laser parameters were: laser wavelength 1064 nm, pulse frequency 1.0 kHz, laser power 15 W, scanning speed 42 cm / s, DPI resolution 1200, and the laser scanning area was 1 cm 2 . After the scanning was completed, a laser-induced copper-nickel-zinc ternary composite electrode was obtained.
[0041] 2. Electrocatalytic nitrate reduction reaction experiment
[0042] Accurately weigh 87.13 g of potassium sulfate and dissolve it in 1000 mL of ultrapure water to prepare an electrolyte solution without nitrate. Accurately weigh 78.417 g of potassium sulfate and 10.1 g of potassium nitrate and dissolve them in 1000 mL of ultrapure water to prepare an electrolyte solution containing nitrate. Using a platinum wire electrode as the counter electrode, an Ag / AgCl electrode as the reference electrode, and a copper-nickel-zinc ternary composite electrode as the working electrode, a three-electrode system is formed. Linear sweep voltammetry tests are respectively carried out in the above electrolyte solutions, controlling the solution temperature at a constant 25 °C, the scanning voltage range is 0 to -1.2 V vs RHE, and the scanning rate is 5 mV / s to obtain a linear sweep voltammogram, as Figure 2 shown.
[0043] It can be seen from Figure 2 that: under the same experimental conditions, the linear sweep voltammetry test curve (curve a) of the electrode in the electrolyte solution without nitrate shows that the current is almost zero before the potential of -0.6 V vs RHE, indicating that there is no electrocatalytic effect. When the potential reaches -0.6 V vs RHE, an obvious catalytic current begins to appear. This current is the hydrogen evolution reaction current for electrocatalytic reduction of hydrogen ions, and the current is relatively low. However, from the linear sweep voltammetry test curve of the electrode in the electrolyte solution containing nitrate, it can be seen that an obvious catalytic current begins to be obtained when the potential reaches -0.15 V vs RHE. Comparing with curve a at the same potential, it can be seen that the catalytic current starting from -0.15 V vs RHE of curve b completely comes from the current of electrocatalytic nitrate reduction. This current increases rapidly with the negative shift of the potential and is much larger than curve a without nitrate. From the above data, it can be obtained that this electrode has a good electrocatalytic reduction effect on nitrate, and it is feasible to use this electrode for electrocatalytic reduction of nitrate.
[0044] Example 2
[0045] 1. Preparation of a laser-induced copper-nickel-zinc ternary composite electrode
[0046] Use a cupronickel alloy sheet to prepare a copper-nickel-zinc ternary composite electrode, and the steps are as follows:
[0047] Place a cupronickel alloy sheet (zinc cupronickel) with dimensions of 30*10*0.5 mm in dilute hydrochloric acid solution for cleaning to remove the surface oxide layer. Dry the cleaned metal sheet and place it in a laser engraving machine. Use a pulsed laser with a wavelength of 1064 nm to scan both sides of the cupronickel alloy sheet. The specific laser parameters are: laser wavelength 1064 nm, pulse frequency 1.0 kHz, laser power 15 W, scanning speed 42 cm / s, DPI resolution 1200, and the laser scanning area is 1 cm 2 , after the scanning is completed, a laser-induced copper-nickel-zinc ternary composite electrode is obtained.
[0048] 2. Electrochemical Catalytic Nitrate Reduction Reaction Experiment
[0049] Accurately weigh 87.13 g of potassium sulfate and dissolve it in 1000 mL of ultrapure water to prepare an anodic electrolyte solution without nitrate. Accurately weigh 78.417 g of potassium sulfate and 10.1 g of potassium nitrate and dissolve them in 1000 mL of ultrapure water to prepare a cathodic electrolyte solution containing nitrate. Use a platinum wire electrode as the counter electrode, an Ag / AgCl electrode as the reference electrode, and a copper-nickel-zinc ternary composite electrode as the working electrode. Adopt an H-type electrolytic cell, separate the anodic chamber and the cathodic chamber with a proton exchange membrane, and fill them with equal volumes of the anodic electrolyte solution and the cathodic electrolyte solution respectively. Insert the working electrode and the reference electrode into the cathodic chamber, and insert the counter electrode into the anodic chamber to form a three-electrode system. Subsequently, use chronopotentiometry to conduct a feasibility test for electrocatalytic ammonia synthesis. The electrocatalytic potential is -0.8 V vs RHE, the electrocatalytic time is 3600 s, control the solution temperature at 25 °C, and obtain a chronopotentiometry curve as shown in Figure 3 shown. After electrocatalysis, take 800 μL of the cathodic electrolyte solution and dilute it 200 times, and then use colorimetry to detect its ammonia content. The standard curve for colorimetric detection of ammonia and the absorbance detection curve are respectively shown in Figure 4 and Figure 5 shown.
[0050] It can be seen from Figure 3 that the chronopotentiometry curve of electrocatalytic reduction of nitrate to ammonia is relatively stable, the current intensity reaches 110 mA / cm 2 , and the total charge is 845.3 C, indicating good electrode stability and high electrocatalytic reduction activity of nitrate. It can be seen from Figure 4 and Figure 5 that the absorbance peak of ammonia detected by colorimetry reaches 0.58, indicating that the ammonia concentration in the cathodic electrolyte solution is 26.4 mM. After calculation, the Faraday efficiency of ammonia can reach 96.5%, and the yield can reach 13.2 mM / h / cm 2 .
[0051] From the above data, it can be obtained that this electrode has good electrocatalytic nitrate reduction to ammonia effect for nitrate, and it is feasible to use this electrode for electrocatalytic ammonia synthesis.
[0052] Comparative Example 1
[0053] 1. Preparation of Copper-Nickel-Zinc Ternary Composite Electrode by Traditional Electrodeposition Method
[0054] Accurately weigh 144.81 g of copper sulfate pentahydrate, 48.39 g of nickel sulfate hexahydrate, and 69.02 g of zinc sulfate heptahydrate, and dissolve them in 1000 mL of aqueous solution containing 1 M sulfuric acid, 0.1 M acetic acid, 50 mM hydrochloric acid, and 0.4 M sodium citrate to prepare the electrolyte solution required for electrodeposition. Use a gold sheet as the substrate electrode for electrodepositing the copper-nickel-zinc ternary composite electrocatalyst. Place a gold sheet with dimensions of 30*10*0.5 mm in acetone and ultrapure water for cleaning to remove surface contaminants. Dry the cleaned gold sheet and use it as the working electrode, a platinum wire electrode as the counter electrode, and an Ag / AgCl electrode as the reference electrode to form a three-electrode system for electrodeposition in the above electrolyte solution. Before the start of electrodeposition, first degas and deoxygenate the electrolyte solution. Electrodeposition is carried out in a constant current mode with a current density of -2.5 A / cm 2 , the electrodeposition temperature is kept constant at 25 °C, the stirring speed is 600 r / min, and the electrodeposition time is 120 s. After the electrodeposition is completed, rinse the obtained electrode with ultrapure water and then air-dry it to obtain the copper-nickel-zinc ternary composite electrode.
[0055] 2. Electrochemical Catalysis of Nitrate Reduction Reaction Experiment
[0056] Accurately weigh 87.13 g of potassium sulfate and dissolve it in 1000 mL of ultrapure water to prepare the anodic electrolyte solution without nitrate. Accurately weigh 78.417 g of potassium sulfate and 10.1 g of potassium nitrate and dissolve them in 1000 mL of ultrapure water to prepare the cathodic electrolyte solution containing nitrate. Use a platinum wire electrode as the counter electrode, an Ag / AgCl electrode as the reference electrode, and the copper-nickel-zinc ternary composite electrode as the working electrode. Adopt an H-type electrolytic cell, separate the anodic chamber and the cathodic chamber with a proton exchange membrane, and fill them with equal volumes of the anodic electrolyte solution and the cathodic electrolyte solution respectively. Insert the working electrode and the reference electrode into the cathodic chamber, and insert the counter electrode into the anodic chamber to form a three-electrode system. Subsequently, conduct a feasibility test for electrocatalytic ammonia synthesis using chronopotentiometry. The electrocatalytic potential is -0.8 V vs RHE, the electrocatalytic time is 3600 s, and the solution temperature is controlled at 25 °C to obtain the chronopotentiometry curve, as Figure 6 shown. After the electrocatalysis is completed, take 800 μL of the cathodic electrolyte solution and dilute it 200 times, and then use colorimetry to detect its ammonia content. The standard curve for colorimetric detection of ammonia and the absorbance detection curve are respectively as Figure 7 and Figure 8 shown.
[0057] It can be seen from Figure 6 that the chronopotentiometry curve for electrocatalytic reduction of nitrate to ammonia is relatively stable. However, its current density is only 63 mA / cm 2 , the total charge is 448 C. Although the electrode stability is also good, the electrocatalytic reduction activity of nitrate reaction is relatively low. It can be seen from Figure 7 andFigure 8 It can be seen that the peak absorbance of ammonia detected by the colorimetric method is 0.24, indicating that the ammonia concentration in the cathode electrolyte solution is only 5.3 mM. After calculation, the Faraday efficiency of ammonia is 36.7%, and the yield is 2.66 mM / h / cm 2 .
[0058] From the above data, it can be obtained that compared with the laser-induced method, the electrocatalytic ammonia synthesis performance of the copper-nickel-zinc ternary composite electrode prepared by the electrodeposition method is lower.
[0059] Comparative Example 2
[0060] 1. The nickel silver alloy sheet not induced by laser
[0061] The nickel silver alloy sheet with a size of 30*10*0.5 mm was placed in acetone and ultrapure water for cleaning to remove surface contaminants. The cleaned nickel silver alloy sheet was dried and reserved.
[0062] 2. Electrocatalytic nitrate reduction reaction experiment
[0063] Accurately weigh 87.13 g of potassium sulfate and dissolve it in 1000 mL of ultrapure water to prepare an anode electrolyte solution without nitrate. Accurately weigh 78.417 g of potassium sulfate and 10.1 g of potassium nitrate and dissolve them in 1000 mL of ultrapure water to prepare a cathode electrolyte solution containing nitrate. Using a platinum wire electrode as the counter electrode, an Ag / AgCl electrode as the reference electrode, and an uninduced nickel silver alloy sheet by laser as the working electrode. An H-type electrolytic cell was used, and the anode chamber and the cathode chamber were separated by a proton exchange membrane, and equal volumes of the anode electrolyte solution and the cathode electrolyte solution were filled respectively. The working electrode and the reference electrode were inserted into the cathode chamber, and the counter electrode was inserted into the anode chamber to form a three-electrode system. Subsequently, chronopotentiometry was used for the feasibility test of electrocatalytic ammonia synthesis. The electrocatalytic potential was -0.8 V vs RHE, and the electrocatalytic time was 3600 s. The solution temperature was controlled at 25 °C to obtain the chronopotentiometry curve, as Figure 9 shown. After electrocatalysis, 800 μL of the cathode electrolyte solution was diluted 50 times, and then the ammonia content was detected by the colorimetric method. The standard curve for the colorimetric detection of ammonia and the absorbance detection curve are respectively as Figure 10 and Figure 11 shown.
[0064] From Figure 9 it can be seen that the chronopotentiometry curve of electrocatalytic reduction of nitrate to ammonia is relatively stable. However, its current intensity is only 55 mA / cm 2 , and the total charge amount is 397.6 C. Although the electrode stability is also good, the electrocatalytic reduction activity of nitrate reaction is low. From Figure 10 and Figure 11It can be seen that the absorbance peak of ammonia detected by the colorimetric method is 0.428, indicating that the ammonia concentration in the cathode electrolyte solution is only 4.18 mM. After calculation, the Faraday efficiency of ammonia is 32.5%, and the yield is 2.09 mM / h / cm 2 .
[0065] From the above data, it can be obtained that the electrocatalytic ammonia synthesis performance of the non-laser-induced nickel silver alloy sheet is lower than that of the laser-induced nickel silver alloy sheet.
[0066] As mentioned above, it is only a preferred embodiment of the present invention, and it is not a limitation of the present invention in other forms. Any person skilled in the art may use the disclosed technical content to make changes or modifications into equivalent embodiments with equivalent changes. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the technical solution content of the present invention still belong to the protection scope of the technical solution of the present invention.
Claims
1. A method for preparing a copper-nickel-zinc ternary composite electrode, characterized in that: The method comprises the following steps: scanning and engraving a white copper alloy sheet by using a pulse laser, and obtaining a copper-nickel-zinc ternary composite electrode after the scanning is completed.
2. The preparation method according to claim 1, characterized in that: The white copper alloy sheet is cleaned with dilute hydrochloric acid before laser engraving to remove the surface oxide layer.
3. The preparation method according to claim 1, characterized in that: The laser scanning parameters are selected from: laser wavelength of 353-1064 nm, pulse frequency of 1-200 kHz, laser power of 10-30 W, scanning speed of 20-60 cm / s, DPI resolution of 800-1200, laser scanning area of 1-100 cm 2 .
4. The preparation method according to claim 1, characterized in that: The nickel silver alloy sheet is one of iron nickel silver, manganese nickel silver, zinc nickel silver and aluminum nickel silver.
5. A copper-nickel-zinc ternary composite electrode prepared by the method according to any one of claims 1 to 4.
6. Use of the copper-nickel-zinc ternary composite electrode according to claim 5 in electrocatalytic nitrate reduction to synthesize ammonia.
7. A method for synthesizing ammonia by electrocatalytic nitrate reduction, characterized in that: The steps include: A platinum wire electrode is used as a counter electrode, an Ag / AgCl electrode is used as a reference electrode, and a copper-nickel-zinc ternary composite electrode is used as a working electrode; an H-type electrolytic cell is used, and the anode chamber and the cathode chamber are separated by a proton exchange membrane, and the anode electrolyte solution and the cathode electrolyte solution are filled respectively; the working electrode and the reference electrode are inserted into the cathode chamber, and the counter electrode is inserted into the anode chamber to form a three-electrode system; then, the electrocatalytic reaction parameters are set to synthesize ammonia by electrocatalytic nitrate reduction; The copper-nickel-zinc ternary composite electrode is the copper-nickel-zinc ternary composite electrode as claimed in claim 5.
8. The method according to claim 7, characterized in that The anode electrolyte solution is a salt solution without nitrate; the salt is selected from one or more of potassium sulfate, sodium sulfate, lithium sulfate and cesium sulfate; the concentration of the salt solution is selected from 300 to 700 mM.
9. The method according to claim 7, characterized in that: The cathode electrolyte solution is a mixed salt solution containing nitrate; the other salt in the mixed salt is selected from one or more of potassium sulfate, sodium sulfate, lithium sulfate, and cesium sulfate; the nitrate is selected from one or more of potassium nitrate, sodium nitrate, lithium nitrate, and cesium nitrate; in the mixed salt solution, the concentration of nitrate is selected from 50 to 150 mM; the concentration of other salt is selected from 100 to 1000 mM.
10. The method according to claim 7, characterized in that The electrocatalytic reaction parameters are selected from: electrocatalytic potential of -0.6 to -1.0 V vs RHE, and electrocatalytic temperature of 20 to 30°C.