A method for fabricating and applying 3D-printed silver-ruthenium co-doped copper nanowire electrodes

Abstract

This invention discloses a method for preparing and applying a 3D-printed silver-ruthenium co-doped copper nanowire electrode. The method includes the following steps: first, using a high-temperature resistant resin as a substrate, the electrode is printed using a micro / nano 3D printer; then, the electrode is sequentially subjected to chemical plating, chemical oxidation, chemical reduction, and chemical doping to obtain the 3D-printed silver-ruthenium co-doped copper nanowire electrode. The 3D-printed silver-ruthenium co-doped copper nanowire electrode prepared by this invention possesses a large number of hierarchical porous structures, providing more active sites for the nitrate reduction to ammonia catalyst. Simultaneously, the introduction of silver and ruthenium modulates the d-band center and electronic structure of copper, further enhancing the performance of nitrate reduction to ammonia. This preparation method has significant advantages such as simple preparation and controllable structure, providing not only insights for the research of the nitrate reduction to ammonia green energy system but also reference value for the design of novel nitrate reduction to ammonia electrode materials.

Description

Technical Field

[0001] This invention belongs to the technical field of electrocatalytic nitrate reduction to ammonia synthesis and the preparation of 3D printed copper electrodes, specifically relating to a method for preparing a 3D printed silver-ruthenium co-doped copper nanowire electrode and its application in electrocatalytic nitrate reduction to ammonia synthesis. Background Technology

[0002] The continued decline of fossil fuels and rapid population growth have led to a severe energy crisis in most parts of the world today. The global scientific community is working to obtain renewable and sustainable energy to meet these growing demands. Industrial-scale ammonia synthesis is considered one of the most influential discoveries of the last century. Due to environmental concerns and the high installation costs of producing ammonia using traditional technologies such as the Haber-Bosch process, researchers are now focusing on simple, efficient, and alternative methods for ammonia synthesis.

[0003] Currently, research on nitrate ions has attracted widespread attention and emerged as a new research area, where nitrate ions are considered a potential source of ammonia production. The electrochemical reduction of nitrate to ammonia (NRA) is an 8-electron, 9-proton transfer reaction involving multiple reaction pathways / intermediate steps and has a lower reaction potential than the hydrogen evolution reaction (HER). Furthermore, in the NRA process, HER can be a disruptive and competing process, where electrons can be used for hydrogen production, which may significantly limit the Faradaic efficiency and selectivity of the reaction system. Therefore, catalyst fabrication has become a key step in addressing the challenges associated with NRA by limiting N≡N bond formation and competing for HER, thus aiding selective reduction and providing the Faradaic efficiency required for practical applications. While several catalyst fabrication techniques have been reported, the need for new alternative strategies is increasing.

[0004] From a manufacturing perspective, traditional molding techniques such as injection molding, and subtractive manufacturing techniques such as drilling, cutting, and milling, while having practical limitations—for example, the complexity associated with equipment and electrode fabrication, as well as time consumption and high costs—have slowed the pace of manufacturing state-of-the-art catalysts. Furthermore, the poor selectivity, stability, activity, and mass transfer limitations associated with catalysts directly restrict their application in catalysis. Therefore, the need for simpler manufacturing methods that can easily tune internal structures and print complex geometries has increased dramatically.

[0005] In recent years, 3D printing technology, as an emerging material and device fabrication technology, has attracted much attention due to its potential applications in electronics, aerospace, medicine, and new energy fields. Advances in technologies such as 3D printing (also known as additive manufacturing) have revolutionized materials manufacturing, offering rapid prototyping capabilities and flexibility in design and printing. This innovative technology has the potential to provide structures with diverse geometries, better rigidity, and adjustable porosity and size, thereby alleviating many limitations associated with traditional manufacturing techniques. Furthermore, designs can be modified relatively easily using computer-aided design (CAD) software. These 3D-printed catalyst structures, with their nanostructures at micron resolution, can induce pores and increase specific surface area, providing nanoscale features that enhance catalytic activity. Simultaneously, 3D-printed catalyst structures can be designed with different geometries, increasing the opportunities to fabricate active catalyst structures for the reduction of nitrates to ammonia.

[0006] Currently, many metals have been explored for use in the electrocatalytic reduction of nitrates to ammonia. Among them, copper, whether alone or in combination with other metals, has shown excellent electrocatalytic reduction performance of nitrates. Theoretical calculations indicate that NO3... − Adsorption on the Cu surface is relatively difficult, which is why NO3 is present. − LUMO π * The high energy makes charge injection into its orbital very unfavorable, becoming the potential-dependent step (PDS) of the NRA process. NO3... − Adsorption on the Cu surface, as the first step in the NRA process, plays a crucial role in catalyzing the entire reaction, providing a good source of NO3. − High coverage is crucial for the reaction to proceed as it suppresses competitive adsorption of other ions. Furthermore, Cu plays a significant role in the catalytic NRA process. * The difficulty in NH3 desorption leads to the poisoning of reaction sites on the Cu surface, limiting the overall reaction rate and affecting the stability of the catalyst during the reaction process. Introducing metals with weaker N adsorption strength than Cu (such as Ag and Au) into Cu can modulate the electronic structure of Cu, thereby... * The interaction between NH3 and the Cu surface reaches an adsorption-desorption equilibrium, thereby improving the activity and stability of the Cu catalyst. Based on this, the present invention prepares a 3D-printed silver-ruthenium co-doped copper nanowire electrode through 3D printing technology, chemical plating, oxidation, reduction, and doping steps for use in the electrocatalytic reduction of nitrate to ammonia synthesis. Currently, there are no related reports in this area. Summary of the Invention

[0007] The technical problem solved by this invention is to provide a method for preparing and applying a 3D-printed silver-ruthenium co-doped copper nanowire electrode. This method successfully prepares a 3D-printed silver-ruthenium co-doped copper nanowire electrode through steps such as 3D printing, chemical plating, oxidation, reduction, and doping. The prepared 3D-printed silver-ruthenium co-doped copper nanowire electrode exhibits excellent activity and stability in the electrocatalytic reduction of nitrate to ammonia.

[0008] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: a method for preparing a 3D-printed silver-ruthenium co-doped copper nanowire electrode, characterized by the following specific process:

[0009] Step S1: Design the electrode structure model using 3D modeling software. The electrode is an ordered porous array structure composed of 10×10 basic units, each basic unit being 0.1cm×0.1cm×0.1cm, with an overall size of 1cm×1cm×0.1cm and a porosity of 92%.

[0010] Step S2: Export the electrode structure model designed in Step S1 as an STL file, and then slice the STL file with a layer thickness of 10μm to obtain a series of two-dimensional images of the electrode structure.

[0011] Step S3: Import the two-dimensional image of the electrode structure processed in step S2 into the micro-nano 3D printer, adjust the printing platform, set the printing parameters, start printing the electrode, take out the printed electrode, rinse it with ethanol, and then cure it in the UV curing chamber to obtain the 3D printed electrode.

[0012] Step S4: The 3D printed electrode obtained in step S3 is subjected to chemical plating pretreatment by immersing it in a mixed solution of KMnO4 and KOH, rinsing it with deionized water, then immersing it in Na2S2O3 solution, rinsing it with deionized water and drying it, and finally immersing it in a mixed solution of AgNO3 and ethanol to obtain the chemically pretreated 3D printed electrode.

[0013] Step S5: The 3D-printed electrode obtained from the pre-treatment in step S4 is subjected to electroless copper plating in an environment containing NaOH, CuSO4·5H2O, HCHO, and C. 10 H 14 N₂Na₂O₈, NaKC₄H₄O₆, C 10 The 3D-printed electrode was obtained by immersing in a solution of H8N2 and K4Fe(CN)6 and then vacuum drying.

[0014] Step S6: The chemically plated copper 3D printed electrode obtained in step S5 is subjected to oxidation treatment by immersing it in a solution containing (NH4)2S2O8 and NaOH to obtain a chemically plated copper and oxidized 3D printed electrode.

[0015] Step S7: The 3D printed electrode obtained in step S6 through chemical copper plating and oxidation treatment is subjected to heat reduction treatment to obtain a 3D printed copper nanowire electrode.

[0016] Step S8: The 3D printed copper nanowire electrode obtained in step S7 is chemically doped with silver and ruthenium by immersing it in a mixed solution of RuCl3 and AgNO3 to obtain a 3D printed silver and ruthenium co-doped copper nanowire electrode.

[0017] Further specifying, the micro-nano 3D printer mentioned in step S3 is the microArch S240 from Mofang Precision, which has an optical precision of 10μm and a printing layer thickness of 10~40μm.

[0018] Further specifying, in step S4, the pretreatment for chemical plating involves immersion at 40°C for 2 minutes in a solution of 7.5 g / L KMnO4 and 20 g / L KOH; immersion at 60°C for 10 minutes in a solution of 5 g / L Na2S2O3; drying at 40°C for 30 minutes; and immersion at 25°C for 10 minutes in a solution of 2 g / L AgNO3 and 50 mL / L ethanol.

[0019] Further specifying, the conditions for electroless copper plating in step S5 are: NaOH 10g / L, CuSO4·5H2O 8g / L, HCHO 12mL / L, C 10 H 14 N2Na2O8 2g / L, NaKC4H4O6 2g / L, C 10 The sample was soaked in a solution of 10 mg / L H8N2 and 20 mg / L K4Fe(CN)6 at 45°C for 40 minutes, and then vacuum dried at 60°C for 6 hours.

[0020] Further specifying, the oxidation treatment conditions in step S6 are: soaking in 0.1 mol / L (NH4)2S2O8 and 1 mol / L NaOH solution for 1 hour, followed by vacuum drying at 60°C for 6 hours.

[0021] Further specifying, the heating and reduction treatment in step S7 is performed by heating at 300°C for 1 hour in a tube furnace, with a hydrogen-argon mixture in the heating and reduction atmosphere.

[0022] Further specifying, the chemical doping of silver ruthenium in step S8 is to soak in a mixed solution of 3 mmol / L RuCl3 and 1~20 mmol / L AgNO3 for 15 minutes.

[0023] The method for preparing a 3D-printed silver-ruthenium co-doped copper nanowire electrode according to the present invention is characterized by the following specific steps:

[0024] Step S1: Design the electrode structure model using 3D modeling software. The electrode is an ordered porous array structure composed of 10×10 basic units, each basic unit being 0.1cm×0.1cm×0.1cm, with an overall size of 1cm×1cm×0.1cm and a porosity of 92%.

[0025] Step S2: Export the electrode structure model designed in Step S1 as an STL file, and then slice the STL file with a layer thickness of 10μm to obtain a series of two-dimensional images of the electrode structure.

[0026] Step S3: Import the two-dimensional image of the electrode structure processed in step S2 into the micro-nano 3D printer, adjust the printing platform, set the printing parameters, start printing the electrode, take out the printed electrode, rinse with ethanol, and then cure in the UV curing chamber for 2 minutes to obtain the 3D printed electrode. The micro-nano 3D printer is the microArch S240 of Mofang Precision. The optical precision of the micro-nano 3D printer is 10μm, and the printing layer thickness is 10μm.

[0027] Step S4: The 3D printed electrode obtained in step S3 is immersed in a solution of KMnO4 7.5 g / L and KOH 20 g / L at 40°C for 2 minutes; immersed in a solution of Na2S2O3 5 g / L at 60°C for 10 minutes; dried at 40°C for 30 minutes; and immersed in a solution of AgNO3 2 g / L and ethanol 50 mL / L at 25°C for 10 minutes to obtain a 3D printed electrode pretreated with electroless plating.

[0028] Step S5: The 3D printed electrode obtained from the pre-chemical plating treatment in step S4 is subjected to NaOH 10g / L, CuSO4·5H2O 8g / L, HCHO 12mL / L, C 10 H 14 N2Na2O8 2g / L, NaKC4H4O6 2g / L, C 10 The electrode was immersed in a solution of 10 mg / L H8N2 and 20 mg / L K4Fe(CN)6 at 45°C for 40 minutes, and then dried at 60°C for 6 hours to obtain a chemically plated copper 3D printed electrode.

[0029] Step S6: Immerse the chemically plated copper 3D printed electrode obtained in step S5 in 0.1 mol / L (NH4)2S2O8 and 1 mol / L NaOH solution for 1 hour, and then vacuum dry at 60℃ for 6 hours to obtain a chemically plated copper and oxidized 3D printed electrode.

[0030] Step S7: Place the chemically plated and oxidized 3D printed electrode obtained in step S6 in a tube furnace and heat it at 300°C for 1 hour under a hydrogen-argon mixed gas to obtain a 3D printed copper nanowire electrode.

[0031] Step S8: The 3D-printed copper nanowire electrode obtained in step S7 is immersed in a mixed solution of 3 mmol / L RuCl3 and 10 mmol / L AgNO3 for 15 minutes to chemically dope silver ruthenium to obtain a 3D-printed silver ruthenium co-doped copper nanowire electrode.

[0032] The application of the 3D-printed silver-ruthenium co-doped copper nanowire electrode described in this invention in the electrocatalytic reduction of nitrate to ammonia synthesis, wherein the Cu metal in the 3D-printed silver-ruthenium co-doped copper nanowire electrode is beneficial for achieving NO3- − To NO2 − During the deoxidation process of the transformation, the high d-band central energy level of metallic Ru allows the introduction of Ru to increase the d-band center of Cu while maintaining the three-dimensional network nanowire structure, thereby enhancing NO3-. − Adsorption on the surface lowers the reaction energy barrier for the first electron transfer process, thereby optimizing the overall reaction kinetics. The introduction of metallic Ag makes Cu... * The desorption of NH3 transforms it into NO3. − The adsorption of ruthenium lowers the overall reaction energy barrier. This 3D-printed silver-ruthenium co-doped copper nanowire electrode exhibits excellent activity and stability in the electrocatalytic reduction of nitrate to ammonia, with a maximum Faraday efficiency of 96.98% and a maximum ammonia yield of 826.16 μmol / h / cm³. 2 .

[0033] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0034] 1. The 3D printing technology involved in this invention possesses rapid prototyping capabilities and design and printing flexibility, leading to significant advancements in materials manufacturing technology. Furthermore, 3D printing technology can easily print structures with complex geometries, adjustable porosity, and dimensions, thereby alleviating multiple limitations associated with traditional manufacturing techniques. These 3D printed structures, with their nanostructures at micron resolution, can induce pores and increase specific surface area, providing nanoscale features beneficial for catalytic reactions. Simultaneously, the designed structures can be modified using computer-aided design (CAD) software, offering simplicity, speed, and convenience.

[0035] 2. This invention utilizes steps such as 3D printing, chemical plating, chemical oxidation, chemical reduction, and chemical doping to control the morphology and electronic structure of 3D-printed silver-ruthenium co-doped copper electrodes, successfully obtaining 3D-printed silver-ruthenium co-doped copper nanowire electrodes. Related research indicates that Cu metal is more conducive to the realization of NO3-. − To NO2 −During the deoxidation process of the transformation, the high d-band central energy level of metallic Ru allows the introduction of Ru to increase the d-band center of Cu while maintaining the three-dimensional network nanowire structure, thereby enhancing NO3-. − Adsorption on the surface lowers the reaction energy barrier for the first electron transfer process, thereby optimizing the overall reaction kinetics. The introduction of metallic Ag makes Cu... * The desorption of NH3 transforms it into NO3. − The adsorption of ruthenium lowers the overall reaction energy barrier. This 3D-printed silver-ruthenium co-doped copper nanowire electrode exhibits excellent activity and stability in the electrocatalytic reduction of nitrate to ammonia, achieving a Faraday efficiency of 96.98% and an ammonia yield of 826.16 μmol / h / cm³. 2 . Attached Figure Description

[0036] Figure 1 The 3D-printed silver-ruthenium co-doped copper electrode F1 prepared in Examples 1-5 is shown. Figure 1 a) 3D printed silver-ruthenium co-doped copper electrode F2 ( Figure 1 (b) 3D printed silver-ruthenium co-doped copper electrode F3 ( Figure 1 c), 3D printed silver-ruthenium co-doped copper electrode F4 ( Figure 1 d), 3D printed silver-ruthenium co-doped copper electrode F5 ( Figure 1 Scanning electron microscope (SEM) image of (e) in the middle;

[0037] Figure 2 These are the X-ray diffraction (XRD) patterns of samples F1 / F2 / F3 / F4 / F5 prepared in Examples 1-5;

[0038] Figure 3 This is the X-ray photoelectron spectroscopy (XPS) image of sample F3 prepared in Example 3. Figure 3 a) High-resolution Cu 2p spectrum ( Figure 3 (b) High-resolution Ru 3p spectrum ( Figure 3 (c) High-resolution Ag 5d spectrum ( Figure 3 (d)

[0039] Figure 4 These are linear sweep voltammetry (LSV) curves of the electrocatalytic nitrate-to-ammonia catalysts for samples F1 / F2 / F3 / F4 / F5 in Examples 1-5. Figure 4(a), LSV curves of sample F3 in Example 3 and samples F6 / F7 / F8 in Comparative Examples 1-3, as well as sample F3 in Example 3 in pure KOH and KOH + KNO3 solutions ( Figure 4 (b)

[0040] Figure 5 The nitrate transammonia faradaic efficiency of the 3D-printed silver-ruthenium co-doped copper electrode F3 prepared in Example 3 at different potentials during the NRA process is shown. Figure 5 a) and ammonia yield diagram ( Figure 5 (b)

[0041] Figure 6 This is a graph showing the nitrate conversion Faraday efficiency and ammonia yield of the 3D-printed silver-ruthenium co-doped copper electrode F3 prepared in Example 3 during the stability test.

[0042] Figure 7 The image shows the nuclear magnetic resonance (1H NMR) spectrum obtained after the 3D-printed silver-ruthenium co-doped copper electrode F3 prepared in Example 3 was reacted in a 14 / 15N nitrate solution.

[0043] Figure 8 This is a process flow diagram of the present invention. Detailed Implementation

[0044] The following examples further illustrate the above-described content of the present invention, but it should not be construed as limiting the scope of the subject matter of the present invention to the following examples. All technologies implemented based on the above-described content of the present invention fall within the scope of the present invention. Example 1

[0045] Step S1: Design the electrode structure model using 3D modeling software. The electrode is an ordered porous array structure composed of 10×10 basic units, each basic unit being 0.1cm×0.1cm×0.1cm, with an overall size of 1cm×1cm×0.1cm and a porosity of 92%.

[0046] Step S2: Export the electrode structure model designed in Step S1 as an STL file, and then slice the STL file with a layer thickness of 10μm to obtain a series of two-dimensional images of the electrode structure.

[0047] Step S3: Import the two-dimensional image of the electrode structure processed in step S2 into the micro-nano 3D printer, adjust the printing platform, set the printing parameters, start printing the electrode, take out the printed electrode, rinse it with ethanol, and then cure it in the UV curing chamber to obtain the 3D printed electrode A1.

[0048] Step S4: Take out the 3D printed electrode A1 and perform a chemical plating pretreatment on it. Immerse it in a mixed solution of KMnO4 (7.5 g / L) and KOH (20 g / L) (immersion temperature 40℃, immersion time 2 minutes), take it out and rinse it with deionized water, then immerse it in a Na2S2O3 (5 g / L) solution (immersion temperature 60℃, immersion time 10 minutes), take it out and rinse it with deionized water and dry it (drying temperature 40℃, drying time 30 minutes). Finally, immerse it in a mixed solution of AgNO3 (2 g / L) and ethanol (50 mL / L) (immersion temperature 25℃, immersion time 10 minutes) to obtain the 3D printed electrode B1.

[0049] Step S5: Chemically plate the 3D-printed electrode B1 with copper in the following solutions: NaOH (10 g / L), CuSO4·5H2O (8 g / L), HCHO (12 mL / L), and C. 10 H 14 N2Na2O8 (2g / L), NaKC4H4O6 (2g / L), C 10 The copper electrode C1 was obtained by soaking in a solution of H8N2 (10 mg / L) and K4Fe(CN)6 (20 mg / L) (soaking temperature 45℃, soaking time 40 minutes) and then vacuum drying (drying temperature 60℃, drying time 6 hours).

[0050] Step S6: The 3D printed copper electrode C1 after chemical copper plating is oxidized by immersing it in 0.1 mol / L (NH4)2S2O8 and 1 mol / L NaOH solution (immersion time 1 hour) to obtain 3D printed electrode D1.

[0051] Step S7: The 3D printed electrode D1, which has undergone chemical copper plating and oxidation treatment, is subjected to heat reduction treatment in a tube furnace (heating temperature 300℃, heating time 1 hour, heating atmosphere hydrogen-argon mixture) to obtain the 3D printed copper nanowire electrode E1.

[0052] Step S8: Immerse the 3D-printed copper nanowire electrode E1 in a mixed solution of 3 mmol / L RuCl3 and 1 mmol / L AgNO3 for 15 minutes to chemically dope silver and ruthenium to obtain the 3D-printed silver and ruthenium co-doped copper nanowire electrode F1. Example 2

[0053] Step S1: Design the electrode structure model using 3D modeling software. The electrode is an ordered porous array structure composed of 10×10 basic units, each basic unit being 0.1cm×0.1cm×0.1cm, with an overall size of 1cm×1cm×0.1cm and a porosity of 92%.

[0054] Step S2: Export the electrode structure model designed in Step S1 as an STL file, and then slice the STL file with a layer thickness of 10μm to obtain a series of two-dimensional images of the electrode structure.

[0055] Step S3: Import the two-dimensional image of the electrode structure processed in step S2 into the micro-nano 3D printer, adjust the printing platform, set the printing parameters, start printing the electrode, take out the printed electrode, rinse it with ethanol, and then cure it in the UV curing chamber to obtain the 3D printed electrode A2.

[0056] Step S4: Take out the 3D printed electrode A2 and perform a chemical plating pretreatment on it. Immerse it in a mixed solution of KMnO4 (7.5 g / L) and KOH (20 g / L) (immersion temperature 40℃, immersion time 2 minutes), take it out and rinse it with deionized water, then immerse it in a Na2S2O3 (5 g / L) solution (immersion temperature 60℃, immersion time 10 minutes), take it out and rinse it with deionized water and dry it (drying temperature 40℃, drying time 30 minutes). Finally, immerse it in a mixed solution of AgNO3 (2 g / L) and ethanol (50 mL / L) (immersion temperature 25℃, immersion time 10 minutes) to obtain the 3D printed electrode B2.

[0057] Step S5: Chemically plate the 3D-printed electrode B2 with copper in the following solutions: NaOH (10 g / L), CuSO4·5H2O (8 g / L), HCHO (12 mL / L), and C. 10 H 14 N2Na2O8 (2g / L), NaKC4H4O6 (2g / L), C 10 The copper electrode C2 was obtained by soaking in a solution of H8N2 (10 mg / L) and K4Fe(CN)6 (20 mg / L) (soaking temperature 45℃, soaking time 40 minutes) and then vacuum drying (drying temperature 60℃, drying time 6 hours).

[0058] Step S6: The 3D printed copper electrode C2 after chemical copper plating is oxidized by immersing it in 0.1 mol / L (NH4)2S2O8 and 1 mol / L NaOH solution (immersion time 1 hour) to obtain the 3D printed electrode D2.

[0059] Step S7: The 3D printed electrode D2, which has undergone chemical copper plating and oxidation treatment, is subjected to heat reduction treatment in a tube furnace (heating temperature 300℃, heating time 1 hour, heating atmosphere hydrogen-argon mixture) to obtain the 3D printed copper nanowire electrode E2.

[0060] Step S8: Immerse the 3D-printed copper nanowire electrode E2 in a mixed solution of 3 mmol / L RuCl3 and 5 mmol / L AgNO3 for 15 minutes to chemically dope silver and ruthenium to obtain the 3D-printed silver and ruthenium co-doped copper nanowire electrode F2. Example 3

[0061] Step S1: Design the electrode structure model using 3D modeling software. The electrode is an ordered porous array structure composed of 10×10 basic units, each basic unit being 0.1cm×0.1cm×0.1cm, with an overall size of 1cm×1cm×0.1cm and a porosity of 92%.

[0062] Step S2: Export the electrode structure model designed in Step S1 as an STL file, and then slice the STL file with a layer thickness of 10μm to obtain a series of two-dimensional images of the electrode structure.

[0063] Step S3: Import the two-dimensional image of the electrode structure processed in step S2 into the micro-nano 3D printer, adjust the printing platform, set the printing parameters, start printing the electrode, remove the printed electrode, rinse it with ethanol, and then cure it in the UV curing chamber to obtain the 3D printed electrode A3.

[0064] Step S4: Take out the 3D printed electrode A3 and perform a chemical plating pretreatment on it. Immerse it in a mixed solution of KMnO4 (7.5 g / L) and KOH (20 g / L) (immersion temperature 40℃, immersion time 2 minutes), take it out and rinse it with deionized water, then immerse it in a Na2S2O3 (5 g / L) solution (immersion temperature 60℃, immersion time 10 minutes), take it out and rinse it with deionized water and dry it (drying temperature 40℃, drying time 30 minutes). Finally, immerse it in a mixed solution of AgNO3 (2 g / L) and ethanol (50 mL / L) (immersion temperature 25℃, immersion time 10 minutes) to obtain the 3D printed electrode B3.

[0065] Step S5: Chemically plate the 3D-printed electrode B3 with copper in the following solutions: NaOH (10 g / L), CuSO4·5H2O (8 g / L), HCHO (12 mL / L), and C. 10 H 14 N2Na2O8 (2g / L), NaKC4H4O6 (2g / L), C 10 The copper electrode C3 was obtained by soaking in a solution of H8N2 (10 mg / L) and K4Fe(CN)6 (20 mg / L) (soaking temperature 45℃, soaking time 40 minutes) and then vacuum drying (drying temperature 60℃, drying time 6 hours).

[0066] Step S6: The 3D printed copper electrode C3 after chemical copper plating is oxidized by immersing it in 0.1 mol / L (NH4)2S2O8 and 1 mol / L NaOH solution (immersion time 1 hour) to obtain the 3D printed electrode D3.

[0067] Step S7: The 3D printed electrode D3, which has undergone chemical copper plating and oxidation treatment, is subjected to heat reduction treatment in a tube furnace (heating temperature 300℃, heating time 1 hour, heating atmosphere hydrogen-argon mixture) to obtain the 3D printed copper nanowire electrode E3.

[0068] Step S8: Immerse the 3D-printed copper nanowire electrode E3 in a mixed solution of 3 mmol / L RuCl3 and 10 mmol / L AgNO3 for 15 minutes to chemically dope silver and ruthenium to obtain the 3D-printed silver and ruthenium co-doped copper nanowire electrode F3. Example 4

[0069] Step S1: Design the electrode structure model using 3D modeling software. The electrode is an ordered porous array structure composed of 10×10 basic units, each basic unit being 0.1cm×0.1cm×0.1cm, with an overall size of 1cm×1cm×0.1cm and a porosity of 92%.

[0070] Step S2: Export the electrode structure model designed in Step S1 as an STL file, and then slice the STL file with a layer thickness of 10μm to obtain a series of two-dimensional images of the electrode structure.

[0071] Step S3: Import the two-dimensional image of the electrode structure processed in step S2 into the micro-nano 3D printer, adjust the printing platform, set the printing parameters, start printing the electrode, remove the printed electrode, rinse it with ethanol, and then cure it in the UV curing chamber to obtain the 3D printed electrode A4.

[0072] Step S4: Take out the 3D printed electrode A4 and perform a chemical plating pretreatment on it. Immerse it in a mixed solution of KMnO4 (7.5 g / L) and KOH (20 g / L) (immersion temperature 40℃, immersion time 2 minutes), rinse it with deionized water, then immerse it in a Na2S2O3 (5 g / L) solution (immersion temperature 60℃, immersion time 10 minutes), rinse it with deionized water and dry it (drying temperature 40℃, drying time 30 minutes). Finally, immerse it in a mixed solution of AgNO3 (2 g / L) and ethanol (50 mL / L) (immersion temperature 25℃, immersion time 10 minutes) to obtain the 3D printed electrode B4.

[0073] Step S5: Chemically plate the 3D-printed electrode B4 with copper in the following solutions: NaOH (10 g / L), CuSO4·5H2O (8 g / L), HCHO (12 mL / L), and C. 10 H 14 N2Na2O8 (2g / L), NaKC4H4O6 (2g / L), C 10 The copper electrode C4 was obtained by soaking in a solution of H8N2 (10 mg / L) and K4Fe(CN)6 (20 mg / L) (soaking temperature 45℃, soaking time 40 minutes) and then vacuum drying (drying temperature 60℃, drying time 6 hours).

[0074] Step S6: The 3D printed copper electrode C4 after chemical copper plating is oxidized by immersing it in 0.1 mol / L (NH4)2S2O8 and 1 mol / L NaOH solution (immersion time 1 hour) to obtain the 3D printed electrode D4.

[0075] Step S7: The chemically plated and oxidized 3D printed electrode D4 is subjected to a heat reduction treatment in a tube furnace (heating temperature 300℃, heating time 1 hour, heating atmosphere hydrogen-argon mixture) to obtain the 3D printed copper nanowire electrode E4.

[0076] Step S8: Immerse the 3D-printed copper nanowire electrode E4 in a mixed solution of 3 mmol / L RuCl3 and 15 mmol / L AgNO3 for 15 minutes to chemically dope silver and ruthenium to obtain the 3D-printed silver and ruthenium co-doped copper nanowire electrode F4. Example 5

[0077] Step S1: Design the electrode structure model using 3D modeling software. The electrode is an ordered porous array structure composed of 10×10 basic units, each basic unit being 0.1cm×0.1cm×0.1cm, with an overall size of 1cm×1cm×0.1cm and a porosity of 92%.

[0078] Step S2: Export the electrode structure model designed in Step S1 as an STL file, and then slice the STL file with a layer thickness of 10μm to obtain a series of two-dimensional images of the electrode structure.

[0079] Step S3: Import the two-dimensional image of the electrode structure processed in step S2 into the micro-nano 3D printer, adjust the printing platform, set the printing parameters, start printing the electrode, take out the printed electrode, rinse it with ethanol, and then cure it in the UV curing chamber to obtain the 3D printed electrode A5.

[0080] Step S4: Take out the 3D printed electrode A5 and perform a chemical plating pretreatment on it. Immerse it in a mixed solution of KMnO4 (7.5 g / L) and KOH (20 g / L) (immersion temperature 40℃, immersion time 2 minutes), take it out and rinse it with deionized water, then immerse it in a Na2S2O3 (5 g / L) solution (immersion temperature 60℃, immersion time 10 minutes), take it out and rinse it with deionized water and dry it (drying temperature 40℃, drying time 30 minutes). Finally, immerse it in a mixed solution of AgNO3 (2 g / L) and ethanol (50 mL / L) (immersion temperature 25℃, immersion time 10 minutes) to obtain the 3D printed electrode B5.

[0081] Step S5: Chemically plate the 3D-printed electrode B5 with copper in the following solutions: NaOH (10 g / L), CuSO4·5H2O (8 g / L), HCHO (12 mL / L), and C. 10 H 14 N2Na2O8 (2g / L), NaKC4H4O6 (2g / L), C 10 The copper electrode C5 was obtained by soaking in a solution of H8N2 (10 mg / L) and K4Fe(CN)6 (20 mg / L) (soaking temperature 45℃, soaking time 40 minutes) and then vacuum drying (drying temperature 60℃, drying time 6 hours).

[0082] Step S6: The 3D printed copper electrode C5 after chemical copper plating is oxidized by immersing it in 0.1 mol / L (NH4)2S2O8 and 1 mol / L NaOH solution (immersion time 1 hour) to obtain the 3D printed electrode D5.

[0083] Step S7: The chemically plated and oxidized 3D printed electrode D5 is subjected to a heat reduction treatment in a tube furnace (heating temperature 300℃, heating time 1 hour, heating atmosphere hydrogen-argon mixture) to obtain the 3D printed copper nanowire electrode E5.

[0084] Step S8: Immerse the 3D-printed copper nanowire electrode E5 in a mixed solution of 3 mmol / L RuCl3 and 20 mmol / L AgNO3 for 15 minutes to chemically dope silver and ruthenium to obtain the 3D-printed silver and ruthenium co-doped copper nanowire electrode F5.

[0085] Comparative Example 1

[0086] Step S1: Design the electrode structure model using 3D modeling software. The electrode is an ordered porous array structure composed of 10×10 basic units, each basic unit being 0.1cm×0.1cm×0.1cm, with an overall size of 1cm×1cm×0.1cm and a porosity of 92%.

[0087] Step S2: Export the electrode structure model designed in Step S1 as an STL file, and then slice the STL file with a layer thickness of 10μm to obtain a series of two-dimensional images of the electrode structure.

[0088] Step S3: Import the two-dimensional image of the electrode structure processed in step S2 into the micro-nano 3D printer, adjust the printing platform, set the printing parameters, start printing the electrode, take out the printed electrode, rinse it with ethanol, and then cure it in the UV curing chamber to obtain the 3D printed electrode A6.

[0089] Step S4: Take out the 3D printed electrode A6 and perform a chemical plating pretreatment on the 3D printed electrode A6. Immerse it in a mixed solution of KMnO4 (7.5 g / L) and KOH (20 g / L) (immersion temperature 40℃, immersion time 2 minutes), take it out and rinse it with deionized water, then immerse it in Na2S2O3 (5 g / L) solution (immersion temperature 60℃, immersion time 10 minutes), take it out and rinse it with deionized water and dry it (drying temperature 40℃, drying time 30 minutes). Finally, immerse it in a mixed solution of AgNO3 (2 g / L) and ethanol (50 mL / L) (immersion temperature 25℃, immersion time 10 minutes) to obtain the 3D printed electrode B6.

[0090] Step S5: Chemically plate the 3D-printed electrode B6 with copper in the following solutions: NaOH (10 g / L), CuSO4·5H2O (8 g / L), HCHO (12 mL / L), and C. 10 H 14 N2Na2O8 (2g / L), NaKC4H4O6 (2g / L), C 10 The copper electrode C6 was obtained by soaking in a solution of H8N2 (10 mg / L) and K4Fe(CN)6 (20 mg / L) (soaking temperature 45℃, soaking time 40 minutes) and then vacuum drying (drying temperature 60℃, drying time 6 hours).

[0091] Step S6: The 3D printed copper electrode C6 after chemical copper plating is oxidized by immersing it in 0.1 mol / L (NH4)2S2O8 and 1 mol / L NaOH solution (immersion time 1 hour) to obtain the 3D printed electrode D6.

[0092] Step S7: The chemically plated and oxidized 3D printed electrode D6 is subjected to a heat reduction treatment in a tube furnace (heating temperature 300℃, heating time 1 hour, heating atmosphere hydrogen-argon mixture) to obtain the 3D printed copper nanowire electrode F6.

[0093] Comparative Example 2

[0094] Step S1: Design the electrode structure model using 3D modeling software. The electrode is an ordered porous array structure composed of 10×10 basic units, each basic unit being 0.1cm×0.1cm×0.1cm, with an overall size of 1cm×1cm×0.1cm and a porosity of 92%.

[0095] Step S2: Export the electrode structure model designed in Step S1 as an STL file, and then slice the STL file with a layer thickness of 10μm to obtain a series of two-dimensional images of the electrode structure.

[0096] Step S3: Import the two-dimensional image of the electrode structure processed in step S2 into the micro-nano 3D printer, adjust the printing platform, set the printing parameters, start printing the electrode, take out the printed electrode, rinse it with ethanol, and then cure it in the UV curing chamber to obtain the 3D printed electrode A7.

[0097] Step S4: Take out the 3D printed electrode A7 and perform a chemical plating pretreatment on it. Immerse it in a mixed solution of KMnO4 (7.5 g / L) and KOH (20 g / L) (immersion temperature 40℃, immersion time 2 minutes), take it out and rinse it with deionized water, then immerse it in a Na2S2O3 (5 g / L) solution (immersion temperature 60℃, immersion time 10 minutes), take it out and rinse it with deionized water and dry it (drying temperature 40℃, drying time 30 minutes). Finally, immerse it in a mixed solution of AgNO3 (2 g / L) and ethanol (50 mL / L) (immersion temperature 25℃, immersion time 10 minutes) to obtain the 3D printed electrode B7.

[0098] Step S5: Chemically plate the 3D-printed electrode B7 with copper in the following solutions: NaOH (10 g / L), CuSO4·5H2O (8 g / L), HCHO (12 mL / L), and C. 10 H 14 N2Na2O8 (2g / L), NaKC4H4O6 (2g / L), C 10 The copper electrode C7 was obtained by soaking in a solution of H8N2 (10 mg / L) and K4Fe(CN)6 (20 mg / L) (soaking temperature 45℃, soaking time 40 minutes) and then vacuum drying (drying temperature 60℃, drying time 6 hours).

[0099] Step S6: The 3D printed copper electrode C7 after chemical copper plating is oxidized by immersing it in 0.1 mol / L (NH4)2S2O8 and 1 mol / L NaOH solution (immersion time 1 hour) to obtain the 3D printed electrode D7.

[0100] Step S7: The 3D printed electrode D7, after chemical copper plating and oxidation treatment, is subjected to heat reduction treatment in a tube furnace (heating temperature 300℃, heating time 1 hour, heating atmosphere hydrogen-argon mixture) to obtain the 3D printed copper nanowire electrode E7.

[0101] Step S8: Immerse the 3D printed copper nanowire electrode E7 in a 3 mmol / L RuCl3 solution for 15 minutes to chemically dope ruthenium to obtain the 3D printed ruthenium-doped copper nanowire electrode F7.

[0102] Comparative Example 3

[0103] Step S1: Design the electrode structure model using 3D modeling software. The electrode is an ordered porous array structure composed of 10×10 basic units, each basic unit being 0.1cm×0.1cm×0.1cm, with an overall size of 1cm×1cm×0.1cm and a porosity of 92%.

[0104] Step S2: Export the electrode structure model designed in Step S1 as an STL file, and then slice the STL file with a layer thickness of 10μm to obtain a series of two-dimensional images of the electrode structure.

[0105] Step S3: Import the two-dimensional image of the electrode structure processed in step S2 into the micro-nano 3D printer, adjust the printing platform, set the printing parameters, start printing the electrode, take out the printed electrode, rinse it with ethanol, and then cure it in the UV curing chamber to obtain the 3D printed electrode A8.

[0106] Step S4: Take out the 3D printed electrode A8 and perform a chemical plating pretreatment on the 3D printed electrode A8. Immerse it in a mixed solution of KMnO4 (7.5 g / L) and KOH (20 g / L) (immersion temperature 40℃, immersion time 2 minutes), take it out and rinse it with deionized water, then immerse it in Na2S2O3 (5 g / L) solution (immersion temperature 60℃, immersion time 10 minutes), take it out and rinse it with deionized water and dry it (drying temperature 40℃, drying time 30 minutes). Finally, immerse it in a mixed solution of AgNO3 (2 g / L) and ethanol (50 mL / L) (immersion temperature 25℃, immersion time 10 minutes) to obtain the 3D printed electrode B8.

[0107] Step S5: Chemically plate the 3D-printed electrode B8 with copper in the following solutions: NaOH (10 g / L), CuSO4·5H2O (8 g / L), HCHO (12 mL / L), and C. 10 H 14 N2Na2O8 (2g / L), NaKC4H4O6 (2g / L), C 10The copper electrode C8 was obtained by soaking in a solution of H8N2 (10 mg / L) and K4Fe(CN)6 (20 mg / L) (soaking temperature 45℃, soaking time 40 minutes) and then vacuum drying (drying temperature 60℃, drying time 6 hours).

[0108] Step S6: The 3D printed copper electrode C8 after chemical copper plating is oxidized by immersing it in 0.1 mol / L (NH4)2S2O8 and 1 mol / L NaOH solution (immersion time 1 hour) to obtain the 3D printed electrode D8.

[0109] Step S7: The chemically plated and oxidized 3D printed electrode D8 is subjected to a heat reduction treatment in a tube furnace (heating temperature 300℃, heating time 1 hour, heating atmosphere hydrogen-argon mixture) to obtain the 3D printed copper nanowire electrode E8.

[0110] Step S8: Immerse the 3D printed copper nanowire electrode E8 in 10 mmol / L AgNO3 solution for 15 minutes to chemically dope it with silver to obtain the 3D printed silver-doped copper nanowire electrode F5.

[0111] NO3RR activity testing procedure: A series of prepared 3D printed electrodes (F1 / F2 / F3 / F4 / F5 / F6 / F7 / F8) were placed in a Pt sheet electrode holder as working electrodes, with mercury / mercuric oxide as the reference electrode and the Pt sheet as the counter electrode. 1 mol L... -1 KOH + 0.1 mol L -1 A KNO3 mixed aqueous solution was used as the electrolyte to construct a three-electrode testing system. LSV measurements were then performed to obtain the LSV polarization curves of the F1–F8 catalysts at a scan rate of 10 mV / s. -1 The potential range is −0.4 ~ −1.6 V; in 1 mol L -1 KOH+ 0.1mol L -1 Chronocurrent response tests were conducted using a KNO3 mixed aqueous solution to obtain chronocurrent curves at different potentials of electrode F3, with a reaction time of 1800 s.

[0112] The surface morphology of samples F1~F5 was observed by SEM, such as Figure 1 As shown, the nanowire structure is maintained, but the surface begins to roughen and has large protrusions. This is due to the coating of Cu nanowires with a layer of Ag and Ru. F1 ( Figure 1 a) and F2 ( Figure 1 On the surface of (b), Ag and Ru loadings are relatively low, while on F3 ( Figure 1 The surface load of c) is more uniform and dense, in F4 ( Figure 1 (d) and F5 ( Figure 1On the surface of sample F1-F5, obvious agglomeration was observed. Samples F1-F5 were characterized by XRD, as shown... Figure 2 As shown, diffraction peaks appeared, which perfectly matched the diffraction peaks of pure metal Cu. Only the Cu(111), Cu(200), and Cu(220) crystal planes were observed, and no diffraction peaks of Ag and Ru were observed, indicating that the content of Ag and Ru may be low or exist in an amorphous structure.

[0113] Sample F3 was characterized using XPS, such as Figure 3 As shown, XPS full spectrum ( Figure 3 In section a), the presence of Cu, Ag, Ru, and O elements is clearly visible. The presence of O is likely due to oxidation of the sample surface caused by exposure to air. The high-resolution Cu 2p spectrum of F3 (…) Figure 3 b) can be fitted to two peaks, a pair of peaks located around 932.48 eV and 952.2 eV, corresponding to Cu, respectively. 0 / 1+ 2p 3 / 2 and Cu 0 / 1+ 2p 1 / 2 The characteristic peaks and observed satellite peaks are likely due to partial surface oxidation of F3 when exposed to air. Combined with XRD results, this indicates that Cu in F3 exists primarily in elemental form. Compared to the 932.8 eV and 952.8 eV of pure Cu, the Cu 2p2 in F3... 3 / 2 and Cu 2p 1 / 2 The shift of the characteristic peak to lower binding energies, specifically the shift in the Cu 2p characteristic peak position, indicates that Ag and Ru atom doping alters the electronic structure of Cu. For example... Figure 3 As shown in Figure c, the binding energies of Ru3p in F3 are centered at 462.5 eV and 484.5 eV, higher than those of metallic Ru (461.6 eV and 483.9 eV), but lower than those of RuO2 (465.0 eV and 488.2 eV), indicating that the valence state of Ru in F3 is between 0 and +4. Figure 3 As shown in Figure d, the spectrum of the Ag 3d region has two peaks at 368.4 eV and 374.4 eV, which belong to Ag 3d and 374.4 eV, respectively. 5 / 2 and Ag 3d 3 / 2 The binding energy difference between them is 6 eV, indicating that the Ag on F3 is metallic silver.

[0114] The NRA catalytic performance of the F1-F5 samples prepared in Examples 1-5 and Comparative Examples 1-3 is as follows: Figure 4 a and Figure 4 As shown in Figure b, F3 exhibits the highest limiting reaction current, demonstrating that sample F3 possesses the best NRA activity; as Figure 5As shown, the F3 sample exhibits the best performance in terms of ammonia yield and Faradaic efficiency at different potentials, with a Faradaic efficiency of 96.98% and an ammonia yield of 826.16 μmol / h / cm³. 2 ;like Figure 6 As shown, the ammonia yield and Faraday efficiency of F3 were calculated by UV colorimetric analysis of the electrolyte after 10 chronocurrent cycles at the optimal potential of −0.2V. No significant decrease was observed, indicating good durability. Figure 7 As shown, when using respectively 14N KNO3 and 15N KNO3 was used as the nitrogen source for the reaction. The resulting electrolyte was then subjected to nuclear magnetic resonance (NMR) analysis to obtain the 1H NMR spectrum. The results indicate that when the nitrogen source is... 14N When KNO3 is used, the ammonia product is... 14N NH3, when the nitrogen source is 15N When KNO3 is used, the ammonia product is... 15N The presence of NH3 clearly indicates that the ammonia product obtained after the reaction indeed originated from the KNO3 reactants.

[0115] The above embodiments describe the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are only illustrative of the principles of the present invention. Various changes and modifications can be made to the present invention without departing from the scope of the principles of the present invention, and all such changes and modifications fall within the protection scope of the present invention.

Claims

1. A method for preparing a 3D printed silver-ruthenium co-doped copper nanowire electrode, characterized in that The specific steps are: Step S1: using 3D modeling software to design electrode structure model, the electrode is an ordered porous array structure, which is composed of 10x10 basic units, each basic unit is 0.1cmx0.1cmx0.1cm, the overall size is 1cmx1cmx0.1cm, and the porosity is 92%; Step S2: the electrode structure model designed in step S1 is exported in STL format, and the STL format file is sliced with a layer thickness of 10μm to obtain a series of two-dimensional pictures of electrode structure; Step S3: the two-dimensional picture of electrode structure sliced in step S2 is imported into micro-nano 3D printer, the printing platform is adjusted, the printing parameters are set, the electrode is printed, the printed electrode is taken out, washed with ethanol, and then cured in a ultraviolet curing box for 2 minutes to obtain a 3D printed electrode, the micro-nano 3D printer is microArch S240 of Mofang Precision, the optical precision of the micro-nano 3D printer is 10μm, and the printing layer thickness is 10μm; Step S4: the 3D printed electrode obtained in step S3 is soaked in KMnO4 7.5g / L and KOH 20g / L solution at 40℃ for 2 minutes, in Na2S2O3 5g / L solution at 60℃ for 10 minutes, and then dried at 40℃ for 30 minutes, and then soaked in AgNO3 2g / L and ethanol 50mL / L solution at 25℃ for 10 minutes to obtain a 3D printed electrode after chemical plating pretreatment; Step S5: the chemical plating pretreated 3D-printed electrode obtained in step S4 is immersed in a solution of NaOH 10 g / L, CuSO4-5H2O 8 g / L, HCHO 12 mL / L, C 10 H 14 N2Na2O8 2 g / L, NaKC4H4O6 2 g / L, C 10 H8N2 10 mg / L and K4Fe(CN)620 mg / L at 45°C for 40 minutes, and then dried at 60°C for 6 hours to obtain a chemical copper-plated 3D-printed electrode; Step S6: the 3D printed electrode after chemical copper plating obtained in step S5 is soaked in 0.1mol / L (NH4)2S2O8 and 1mol / L NaOH solution for 1 hour, and then vacuum dried at 60℃ for 6 hours to obtain a 3D printed electrode after chemical copper plating and oxidation treatment; Step S7: the 3D printed electrode after chemical copper plating and oxidation treatment obtained in step S6 is placed in a tube furnace and heated at 300℃ for 1 hour under hydrogen and argon mixed gas to obtain a 3D printed copper nanowire electrode; Step S8: the 3D printed copper nanowire electrode obtained in step S7 is soaked in a mixed solution of 3mmol / L RuCl3 and 10mmol / L AgNO3 for 15 minutes to perform chemical doping of silver and ruthenium to obtain a 3D printed silver and ruthenium co-doped copper nanowire electrode.

2. Application of the 3D printed silver and ruthenium co-doped copper nanowire electrode prepared by the method of claim 1 in electrocatalytic reduction of nitrate to synthesize ammonia.

3. Use according to claim 2, characterized in that: The Cu metal in the 3D-printed silver-ruthenium co-doped copper nanowire electrode is conducive to realizing the conversion of NO3 − to NO2 − The deoxidation process, the metal Ru has a higher d-band center energy level, which can make the Ru introduction to improve the d-band center of Cu while keeping the three-dimensional network-like nanowire structure unchanged, enhance the NO3 − adsorption on the surface, and further reduce the reaction energy barrier of the first electron transfer process, thereby optimizing the overall reaction kinetics. The introduction of metal Ag makes Cu change from * NH3 desorption to NO3 − adsorption, which reduces the overall reaction energy barrier; the 3D-printed silver-ruthenium co-doped copper nanowire electrode exhibits excellent nitrate reduction synthesis ammonia activity and stability in the electrocatalytic reduction of nitrate to synthesize ammonia, with a Faraday efficiency of up to 96.98% and an ammonia yield of up to 826.16 μmol / h / cm 2 .

Images