Photo-thermal driven strong-weak convection coupled nitrite to ammonia electrode and preparation method thereof
By constructing a photothermal-driven strong-weak convection coupled electrode for nitrite ammonia production, the problems of limited mass transfer and single catalyst active site were solved by utilizing the synergistic effect of photothermal effect and fluid dynamics, thus achieving high ammonia yield and Faraday efficiency improvement.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- NANTONG UNIV
- Filing Date
- 2026-03-30
- Publication Date
- 2026-06-26
AI Technical Summary
In existing electrocatalytic ammonia production technologies, the limitations of mass transfer and the single active site of the catalyst restrict the improvement of the reaction rate, and the existing designs fail to fully utilize the synergistic effect of photothermal effect and fluid mass transfer.
A three-dimensional carrier with dual-scale asymmetric traps was constructed by photopolymerization 3D printing technology. Combined with photothermal-driven strong and weak convection coupling, a copper-based heterojunction catalytic layer was constructed to achieve active transport of reactants and timely desorption of products, thereby enhancing mass transfer efficiency and catalytic activity.
It significantly improved catalytic activity and mass transfer efficiency, increased ammonia yield by 80%, achieved a Faraday efficiency of 96%, and exhibited a Tafel slope superior to that of traditional electrodes, demonstrating highly efficient and stable electrochemical performance.
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Figure CN122279674A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of electrocatalytic ammonia production technology, specifically relating to a photothermal driven strong-weak convection coupled nitrite ammonia production electrode and its preparation method. Background Technology
[0002] Ammonia is a core chemical in modern society, serving as a fertilizer raw material for ensuring global food security and a highly promising hydrogen carrier in future clean energy systems. Currently, industrial ammonia production mainly relies on the Haber-Bosch process, which uses iron / ruthenium-based catalysts and requires high temperatures of 300-500℃ and high pressures of 100-200 atm to produce ammonia from the reaction of hydrogen and nitrogen derived from fossil fuels. This process suffers from high energy consumption, large carbon emissions, and complex equipment, contradicting the "dual-carbon" goals and the demands of sustainable development. Electrocatalytic ammonia production technology uses nitrite or nitrate and water as raw materials, driving the reaction with electricity at ambient temperature and pressure. It can be directly coupled with renewable energy sources such as solar and wind power to achieve low-carbon or even zero-carbon ammonia production. Furthermore, it offers advantages such as flexible equipment and modular application adaptability, making it a core direction for green ammonia production.
[0003] However, existing electrocatalytic ammonia production technology still faces key bottlenecks: (1) Traditional catalytic electrodes mostly adopt flat plates or simple two-dimensional structures. During the reaction process, a concentration polarization layer is easily formed on the electrode surface. The mass transfer of reactants to active sites depends on slow natural diffusion, resulting in insufficient reactant supply under high current density, which limits the further improvement of the reaction rate; (2) The nitrite reduction reaction involves a multi-proton-electron transfer process. The adsorption energy barrier of intermediates is high, and the competition of hydrogen evolution side reactions is fierce. Traditional catalysts cannot simultaneously achieve high activity, high selectivity and long-term stability.
[0004] In terms of catalytic materials, copper-based catalysts are the mainstream materials for the reduction of nitrite to ammonia. However, mono-anion copper-based catalysts suffer from problems such as a single active site, poor matching of intermediate adsorption energies, and limited space for electronic structure regulation. Although multi-anion-doped copper-based catalysts can optimize catalytic performance, existing preparation methods often have simple structural designs and fail to fully utilize the synergistic effect of photothermal effect and fluid mass transfer.
[0005] To address the aforementioned mass transfer limitations, existing technologies primarily improve electrode performance by constructing porous structures or increasing specific surface area. However, such designs often only provide static diffusion channels and cannot actively break down the mass transfer boundary layer at the electrode-solution interface. Furthermore, existing electrode structures mostly employ planar or simple two-dimensional configurations, where mass transfer relies on the natural diffusion of reactants, making it difficult to generate active convective mass transfer. Although illumination has been shown to generate photothermal effects and light-induced microconvection on the electrode surface, current research still treats it only as an independent energy input method and has not yet intrinsically coupled it with the hydrodynamic design of the electrode structure. Summary of the Invention
[0006] This invention provides a photothermal driven strong-weak convection coupled electrode for nitrite ammonia production and its preparation method. Through synergistic innovation in electrode material system, microstructure and photothermal multi-physics field coupling effect, a strong-weak convection coupled structure with photothermal response characteristics and asymmetric three-dimensional morphology is constructed, thereby significantly improving the catalytic activity, mass transfer efficiency and cycle stability of the electrode.
[0007] This invention provides a method for preparing a photothermally driven, strong-weak convection coupled nitrite ammonia production electrode, comprising the following steps:
[0008] Step 1: A three-dimensional carrier with dual-scale asymmetric trap units is prepared by photopolymerization 3D printing technology, and a pure copper conductive layer is deposited on the surface of the three-dimensional carrier.
[0009] Step 2: The copper-plated three-dimensional carrier is subjected to oxidation etching, acid coordination treatment and alkaline reduction treatment in sequence to construct a copper-based heterojunction catalytic layer on the surface of the three-dimensional carrier.
[0010] Step 3: After reduction reaction, a nitrite ammonia production electrode is obtained.
[0011] Preferably, in step 1, the 3D printing parameters are: light source wavelength 405nm, single-layer exposure time 5~15s, single-layer thickness 25~100μm, printing fill density 30%~80%, and printing speed 20~60mm / s; after printing, the material is cleaned with ethanol and then subjected to UV secondary curing for 10~30min.
[0012] Preferably, in step 1, the dual-scale asymmetric trap units are a large-scale trap and a small-scale trap, which are connected by a straight channel of equal diameter; wherein, the large-scale trap has a diameter of 2~3mm and an inscribed angle of 20~30°; the small-scale trap has a diameter of 1~2mm and an inscribed angle of 10~15°, and the straight channel has a length of 0.5~1.5mm.
[0013] Preferably, both the large-scale trap and the small-scale trap have isosceles triangular internal folds with a constant apex angle on their inner walls, forming a tortuous interface through local excision; wherein the apex angle is 1~5°.
[0014] Preferably, the configuration of the three-dimensional carrier is selected from at least one of SC lattice, DSHG lattice, DLHG lattice, SLHG lattice and LTAG lattice.
[0015] Preferably, in step 2, the specific method of the oxidation etching treatment is as follows: immerse the three-dimensional carrier in a mixed solution of oxidant and alkaline regulator, soak it at 20~80℃ for 40~100min, and then take it out and dry it; wherein, the oxidant is selected from at least one of sodium persulfate, potassium persulfate, potassium permanganate, potassium dichromate, chromic anhydride, hydrogen peroxide, sodium hypochlorite, ammonium persulfate, and ammonium persulfate-ferrous sulfate composite system, and the concentration is 0.01~1M; the alkaline regulator is selected from at least one of sodium hydroxide, potassium hydroxide, lithium hydroxide, cesium hydroxide, potassium carbonate, sodium carbonate, sodium bicarbonate, and tetramethylammonium hydroxide, and the concentration is 1~5M.
[0016] Preferably, in step 2, the acidic coordination treatment specifically involves immersing the oxidized and etched three-dimensional carrier in a coordination agent solution at 20-100°C for 40-100 minutes, then removing and drying it; wherein the coordination agent is selected from at least one of malonic acid, succinic acid, phthalic acid, pyromellitic acid, squaric acid, citric acid, tartaric acid, disodium EDTA, salicylic acid, terephthalic acid, and maleic acid, and its concentration is 0.1-1.0M.
[0017] Preferably, in step 2, the alkaline reduction treatment specifically involves immersing the acid-coordinated three-dimensional carrier in a mixed solution containing a reducing agent and an alkaline regulator for 10-60 minutes.
[0018] The present invention also provides a photothermal driven strong and weak convection coupled nitrite ammonia production electrode, which is prepared by any of the above-described preparation methods.
[0019] Preferably, the electrode comprises a three-dimensional carrier, a pure copper conductive layer, and a copper-based heterojunction catalytic layer; the three-dimensional carrier has a dual-scale asymmetric trap unit structure; the copper-based heterojunction catalytic layer is a multi-anion-doped copper-based heterojunction composed of crystalline copper, crystalline cuprous oxide, and amorphous copper organic complexes.
[0020] One or more technical solutions provided in the embodiments of this application have at least the following technical effects:
[0021] 1. This invention constructs a dual-scale asymmetric trap array with a size gradient distribution using photopolymerization 3D printing technology. During the reaction process, the local ammonia concentration difference caused by reaction consumption within traps of different sizes can spontaneously induce a strong-weak coupling convection effect. The concentration difference between traps of different sizes drives the formation of a material cycle, realizing the rapid replenishment of reactants and the timely desorption of products.
[0022] Building upon this, illumination further generates a dual convection enhancement mechanism: on the one hand, the temperature gradient on the electrode surface caused by the photothermal effect can induce natural convection, breaking the concentration polarization layer on the electrode surface; on the other hand, the light field gradient can induce the generation of micro-vortex structures, significantly improving local mass transfer efficiency. The synergistic effect of photothermal-driven convection and structural asymmetry-driven convection transforms reactants from "passively waiting" to "actively transporting," fundamentally breaking through the mass transfer bottleneck of traditional electrodes and improving catalytic activity.
[0023] 2. The inner wall of the trap of the electrode of the present invention is provided with an isosceles triangular pleated structure, which enhances the electrocatalytic performance through multiple mechanisms: ① At the level of fluid dynamics, the pleats transform laminar flow into turbulent flow, reducing the concentration boundary layer by more than 60%, forming micro-vortices in small traps to enhance micro-mixing, enhancing mass transfer near the wall of large traps, and maintaining the concentration difference between traps required to drive strong and weak convection; ② At the level of concentration distribution, turbulent scouring accelerates the replenishment of reactants and the desorption of ammonia products, preventing poisoning of active sites, maintaining a high level of reactant concentration in small traps, and achieving dynamic equilibrium of the ammonia environment; ③ At the level of catalytic activity, the pleats increase the active surface area by 80%, enriching high-index crystal faces and oxygen vacancies at the peak, while enhancing light absorption and thermal localization, so that the photothermal effect and strong and weak convection form a positive feedback loop, ultimately achieving a synergistic improvement in ammonia yield and Faraday efficiency.
[0024] 3. This invention constructs a multi-anion-doped copper-based heterojunction catalyst layer through a multi-step chemical process. A heterojunction is formed by encapsulating crystalline copper oxide and crystalline copper with an amorphous copper organic complex (such as copper squaric acid, copper citrate, or copper terephthalate). This heterojunction optimizes the NO2 response through the electronic coupling effect between the amorphous and crystalline interfaces. - The adsorption energy of the reaction intermediate lowers the reaction energy barrier, thereby significantly suppressing the hydrogen evolution side reaction and improving the Faraday efficiency and ammonia yield.
[0025] 4. Synergistic Enhancement of Comprehensive Electrochemical Performance through Photothermal-Fluid Multi-Field Coordination: The technical solution of this invention achieves multi-field coupling of thermal, fluid, and concentration fields in the electrode under photothermal drive through the synergistic effect of structural design and material regulation. Test results (see Example 1) show that the LTAG lattice structure electrode prepared in this invention achieves an ammonia yield of 2.6 mmol·h in a 1M KOH + 1M KNO2 electrolyte under simulated sunlight irradiation. -1 ·cm -2 The Faraday efficiency reached 96%, and the Tafel slope was 51.7 mV / dec. The current of the five electrode configurations (SC, DSHG, DLHG, SLHG, LTAG) increased sequentially at the same potential, and all of them were significantly better than the traditional planar electrode and the control sample under dark conditions, showing significantly better electrochemical performance than the traditional electrode structure and the dark conditions. Attached Figure Description
[0026] Figure 1 The diagram shows the structure of the electrode of the present invention, corresponding to five structures: SC lattice, DSHG lattice, DLHG lattice, SLHG lattice, and LTAG lattice.
[0027] Figure 2 The XRD pattern of the electrode of this invention (showing characteristic peaks of Cu2O phase and Cu phase);
[0028] Figure 3 The TEM microstructure of the electrode interface of this invention is shown (labeled Cu, Cu2O, and CuC4O4 phases).
[0029] Figure 4 The LSV curves of electrodes with different structures in Embodiment 1 of the present invention are shown.
[0030] Figure 5 This is a comparison of ammonia yield and Faraday efficiency at the same potential for electrodes with different structures in Example 1 of the present invention;
[0031] Figure 6 This is a comparison of the Tafel slopes of electrodes with different structures in Embodiment 1 of the present invention.
[0032] Figure 7 This is a schematic diagram of the ammonia environment inside traps of different sizes according to the present invention (the density of lines represents the ammonia concentration, and the flow rate is the opposite of the concentration).
[0033] Figure 8 This is a schematic diagram of the ammonia environment inside a trap of the same large size;
[0034] Figure 9 This is a schematic diagram of the ammonia environment inside a small-sized trap. Detailed Implementation
[0035] This application provides a method for preparing a nitrite ammonia production electrode using photothermal-driven strong-weak coupling convection. By constructing a dual-scale asymmetric trap structure and coupling it with photothermal-driven strong-weak convection, it achieves efficient mass transfer and improved catalytic performance.
[0036] The technical solution in this application is to solve the above problems, and the overall approach is as follows:
[0037] First, based on an asymmetric three-dimensional structure, a dual-scale trap array is constructed. The concentration differences within the traps of different scales drive strong and weak convection coupling, achieving active transport of reactants and timely desorption of products, overcoming the mass transfer bottleneck of traditional electrodes that rely on concentration gradient diffusion. Building upon this, a photothermal effect is introduced, utilizing light-induced micro-convection and thermal gradients to further enhance local mass transfer, forming a multi-physics synergy with structure-driven strong and weak convection. Through synergistic innovation in material systems, microstructures, and photothermal multi-physics coupling, this invention constructs a micro-reaction environment with synergistic thermal, flow, and concentration fields. It surpasses the technological advancements of purely strong and weak convection schemes in three core dimensions: catalytic activity, mass transfer efficiency, and cycle stability, providing a highly efficient and stable electrode solution for nitrite reduction to ammonia production.
[0038] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods.
[0039] Example 1
[0040] Step 1: Preparation of the three-dimensional carrier
[0041] A UV-curing 3D printer was used with photosensitive polyacrylate as the printing material to prepare three-dimensional carriers using five configurations: SC lattice, DSHG lattice, DLHG lattice, SLHG lattice, and LTAG lattice. The printing parameters were set as follows: light source wavelength 405 nm, single-layer exposure time 12 s, single-layer thickness 50 μm, printing infill density 60%, and printing speed 40 mm / s. After printing, the uncured resin was removed by ultrasonic cleaning with anhydrous ethanol for 5 min, followed by a second UV curing for 20 min to obtain the three-dimensional carriers.
[0042] The three-dimensional carrier structure contains dual-scale asymmetric trap units, wherein the large-scale trap has a diameter of 2.8 mm and an incision angle of 25°; the small-scale trap has a diameter of 1.5 mm and an incision angle of 12°; the straight channel between the large and small traps has a length of 1.2 mm; the inner wall of the trap is provided with isosceles triangular internal folds with a vertex angle of 3°, and a tortuous interface is formed by local excision.
[0043] The aforementioned three-dimensional carrier was placed in an electroplating solution, with pure copper as the anode, and electroplated for 30 minutes at a current density of 2 A / dm², forming a pure copper conductive layer with a thickness of approximately 8 μm on the carrier surface. After electroplating, the carrier was rinsed with deionized water and dried.
[0044] Step 2: Multi-step chemical treatment
[0045] The copper-plated substrate was immersed in an oxidation etching solution, which was a mixed solution containing 0.2 M ammonium persulfate and 1.0 M potassium hydroxide, at 30°C for 40 min. After removal, it was rinsed with deionized water and dried in an oven at 60°C.
[0046] The dried carrier was immersed in a 0.5 M squaric acid aqueous solution at 50°C for 80 min. After removal, it was rinsed with deionized water and dried in an oven at 60°C.
[0047] The coordinated support was immersed in a reducing solution, which was a mixed solution containing 0.1 M sodium borohydride and 0.08 M potassium hydroxide, and reduced at room temperature for 60 min. After removal, it was thoroughly rinsed with deionized water to obtain the corresponding five target catalytic electrodes.
[0048] Step 3 Performance Verification
[0049] Five target electrodes were prepared and used as working electrodes in the electrocatalytic reduction of nitrite to ammonia reaction. The electrolyte was 1M KOH + 1M KNO2. A platinum sheet was used as the counter electrode and Ag / AgCl as the reference electrode. The reaction was carried out under simulated sunlight (AM 1.5G, 100mW / cm²). 2 Electrochemical tests were conducted under irradiation. The results showed that the current of the five target catalytic electrodes (SC lattice, DSHG lattice, DLHG lattice, SLHG lattice, and LTAG lattice) increased sequentially at the same potential. The ammonia yield of the SC lattice electrode was 1.1 mmol·h⁻¹. -1 ·cm -2 The Faraday efficiency was 82%; the ammonia yield of the DSHG lattice electrode was 1.4 mmol·h⁻¹. -1 ·cm -2 The Faraday efficiency was 86%; the ammonia yield of the DLHG lattice configuration electrode was 1.8 mmol·h⁻¹. -1 ·cm -2 The Faraday efficiency was 89%; the ammonia yield of the SLHG lattice configuration electrode was 2.0 mmol·h⁻¹. -1 ·cm -2 The Faraday efficiency is 93%; and the ammonia yield of the target catalytic electrode corresponding to the LTAG lattice is 2.6 mmol·h⁻¹. -1 ·cm -2 The Faraday efficiency reaches 96%, and the Tafel slope is 51.7 mV / dec, exhibiting the best electrochemical performance.
[0050] Example 2
[0051] Step 1: Preparation of the three-dimensional carrier
[0052] A UV-curing 3D printer was used with photosensitive polyacrylate as the printing material to prepare three-dimensional carriers using five configurations: SC lattice, DSHG lattice, DLHG lattice, SLHG lattice, and LTAG lattice. The printing parameters were set as follows: light source wavelength 405 nm, single-layer exposure time 12 s, single-layer thickness 50 μm, printing infill density 60%, and printing speed 40 mm / s. After printing, the uncured resin was removed by ultrasonic cleaning with anhydrous ethanol for 5 min, followed by a second UV curing for 20 min to obtain the three-dimensional carriers.
[0053] The three-dimensional carrier structure contains dual-scale asymmetric trap units, wherein the large-scale trap has a diameter of 2.0 mm and an incision angle of 20°; the small-scale trap has a diameter of 1.0 mm and an incision angle of 12°; the straight channel between the large and small traps has a length of 1.0 mm; the inner wall of the trap is provided with isosceles triangular internal folds with a vertex angle of 3°, and a tortuous interface is formed by local excision.
[0054] The aforementioned three-dimensional carrier was placed in an electroplating solution, with pure copper as the anode, and electroplated for 30 minutes at a current density of 2 A / dm², forming a pure copper conductive layer with a thickness of approximately 8 μm on the carrier surface. After electroplating, the carrier was rinsed with deionized water and dried.
[0055] Step 2: Multi-step chemical treatment
[0056] The copper-plated substrate was immersed in an oxidation etching solution, which was a mixed solution containing 0.05M potassium persulfate and 2M sodium hydroxide, at 60°C for 60 min. After removal, it was rinsed with deionized water and dried in an oven at 50°C.
[0057] The dried carrier was immersed in a 0.5 M citric acid solution at 60°C for 60 min. After removal, it was rinsed with deionized water and dried in an oven at 50°C.
[0058] The coordinated support was immersed in a reducing solution, which was a mixed solution containing 0.05 M potassium borohydride and 0.05 M potassium hydroxide, and reduced at room temperature for 30 min. After removal, it was thoroughly rinsed with deionized water to obtain the corresponding five target catalytic electrodes.
[0059] Step 3 Performance Verification
[0060] Five target electrodes were prepared and used as working electrodes in the electrocatalytic reduction of nitrite to ammonia reaction. The electrolyte was 1M KOH + 1M KNO2. A platinum sheet was used as the counter electrode and Ag / AgCl as the reference electrode. The reaction was carried out under simulated sunlight (AM 1.5G, 100mW / cm²). 2 Electrochemical tests were performed under irradiation. The results showed that the ammonia yield of the SC lattice electrode was 1.3 mmol·h⁻¹. -1 ·cm -2 The Faraday efficiency was 82%; the ammonia yield of the DSHG lattice electrode was 1.6 mmol·h⁻¹. -1 ·cm -2 The Faraday efficiency was 86%; the ammonia yield of the DLHG lattice configuration electrode was 1.9 mmol·h⁻¹. -1 ·cm -2 The Faraday efficiency was 89%; the ammonia yield of the SLHG lattice configuration electrode was 2.2 mmol·h⁻¹. -1 ·cm -2 The Faraday efficiency was 93%; the ammonia yield of the LTA Glattice configuration electrode reached 2.6 mmol·h⁻¹. -1 ·cm -2 The Faraday efficiency was 96%, and the Tafel slope was 52.3 mV / dec. These results indicate that the LTAG lattice configuration electrode exhibits the best overall electrochemical performance, and the performance of all five configuration electrodes is significantly superior to that of the conventional planar electrode and the control sample under dark conditions.
[0061] Example 3
[0062] Step 1: Preparation of the three-dimensional carrier
[0063] A three-dimensional carrier was prepared using a UV-curing 3D printer with photosensitive polyacrylate as the printing material and an LTAG lattice configuration. The printing parameters were set as follows: light source wavelength 405 nm, single-layer exposure time 8 s, single-layer thickness 30 μm, infill density 70%, and printing speed 30 mm / s. After printing, the carrier was ultrasonically cleaned with anhydrous ethanol for 5 min to remove uncured resin, followed by a second UV curing for 25 min to obtain the three-dimensional carrier.
[0064] The three-dimensional carrier structure contains dual-scale asymmetric trap units, wherein the large-scale trap has a diameter of 2.2 mm and an incision angle of 28°; the small-scale trap has a diameter of 1.8 mm and an incision angle of 14°; the straight channel between the large and small traps has a length of 0.8 mm; the inner wall of the trap is provided with isosceles triangular internal folds with a vertex angle of 4°, and a tortuous interface is formed by local excision.
[0065] The aforementioned three-dimensional carrier was placed in an electroplating solution, with pure copper as the anode, and electroplated for 30 minutes at a current density of 2 A / dm², forming a pure copper conductive layer with a thickness of approximately 10 μm on the carrier surface. After electroplating, the carrier was rinsed with deionized water and dried.
[0066] Step 2: Multi-step chemical treatment
[0067] The copper-plated substrate was immersed in an oxidation etching solution, which was a mixed solution containing 0.1M hydrogen peroxide and 3M potassium carbonate, at 40°C for 80 min. After removal, it was rinsed with deionized water and dried in an oven at 50°C. Hydrogen peroxide, as a mild oxidant, can form a finer copper oxide nanostructure.
[0068] The dried carrier was immersed in a coordination solution (0.2 M terephthalic acid solution) at 80°C for 80 min. After removal, it was rinsed with deionized water and dried in an oven at 60°C. In this process, terephthalic acid coordinates with copper ions to form a copper terephthalate metal-organic framework structure, which constitutes a heterostructure with copper oxide and metallic copper.
[0069] The coordinated support was immersed in a reducing solution, which was a mixed solution containing 0.02 M ascorbic acid and 0.03 M lithium hydroxide, and reduced at room temperature for 45 min. After removal, it was thoroughly rinsed with deionized water to obtain the target catalytic electrode.
[0070] Step 3 Performance Verification
[0071] The prepared target electrode was used as the working electrode in the electrocatalytic reduction of nitrite to ammonia reaction. The electrolyte was 1M KOH + 1M KNO2. A platinum sheet was used as the counter electrode and Ag / AgCl as the reference electrode. The reaction was carried out under simulated sunlight (AM 1.5G, 100 mW / cm²). 2 Electrochemical tests were performed under irradiation. The results showed that the ammonia yield of this LTAG lattice electrode reached 2.4 mmol·h⁻¹. -1 ·cm -2 The Faraday efficiency was 94%, and the Tafel slope was 55.6 mV / dec. Compared with the electrode prepared using squaric acid coordination in Example 1, the metal-organic framework heterostructure constructed using terephthalic acid coordination in this example also exhibited excellent catalytic performance, verifying the universality of the preparation method described in this invention. Under photothermal-driven strong-weak coupling convection, the mass transfer efficiency of this electrode was significantly improved, and its overall electrochemical performance was significantly better than that of the traditional planar electrode and the control sample under dark conditions.
[0072] In the embodiments of this application, the oxidizing etching solution in step 2 is a mixed solution of oxidant and alkaline regulator. The oxidant may be at least one of sodium persulfate, potassium permanganate, potassium dichromate, chromic anhydride, sodium hypochlorite, and ammonium persulfate-ferrous sulfate composite system. The alkaline regulator is at least one of lithium hydroxide, cesium hydroxide, sodium carbonate, sodium bicarbonate, and tetramethylammonium hydroxide, to replace the potassium persulfate, hydrogen peroxide, and ammonium persulfate oxidants, and sodium hydroxide, potassium hydroxide, and potassium carbonate alkaline regulators listed in Examples 1-3.
[0073] The complexing solution in step 2 can also be at least one of malonic acid, succinic acid, phthalic acid, pyromellitic acid, tartaric acid, disodium EDTA, salicylic acid, and maleic acid, in place of squaric acid, citric acid, and terephthalic acid listed in Examples 1-3.
[0074] The reducing solution in step 2 is a mixed solution of a reducing agent and an alkalinity regulator. The reducing agent may be at least one of dimethylamine borane, hydrazine hydrate, sodium hypophosphite, lithium borohydride, hydrazine aqueous solution, formaldehyde solution, or glucose. The alkalinity regulator is at least one of sodium hydroxide, cesium hydroxide, potassium carbonate, sodium carbonate, sodium bicarbonate, or tetramethylammonium hydroxide. Potassium borohydride, sodium borohydride, and ascorbic acid reducing agents, and potassium hydroxide and lithium hydroxide alkalinity regulators listed in Examples 1-3 are used instead.
[0075] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.
[0076] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.
Claims
1. A method for preparing a photothermally driven, strong-weak convection coupled nitrite ammonia production electrode, characterized in that, Includes the following steps: Step 1: A three-dimensional carrier with dual-scale asymmetric trap units is prepared by photopolymerization 3D printing technology, and a pure copper conductive layer is deposited on the surface of the three-dimensional carrier. Step 2: The copper-plated three-dimensional carrier is subjected to oxidation etching, acid coordination treatment and alkaline reduction treatment in sequence to construct a copper-based heterojunction catalytic layer on the surface of the three-dimensional carrier. Step 3: After reduction reaction, a nitrite ammonia production electrode is obtained.
2. The preparation method according to claim 1, characterized in that, In step 1, the 3D printing parameters are: light source wavelength 405nm, single-layer exposure time 5~15s, single-layer thickness 25~100μm, printing fill density 30%~80%, and printing speed 20~60mm / s. After printing, the product is cleaned with ethanol and then cured under UV light for 10-30 minutes.
3. The preparation method according to claim 1, characterized in that, In step 1, the dual-scale asymmetric trap unit consists of a large-scale trap and a small-scale trap, which are connected by a straight channel of equal diameter; wherein, the large-scale trap has a diameter of 2~3mm and an inscribed angle of 20~30°; the small-scale trap has a diameter of 1~2mm and an inscribed angle of 10~15°, and the straight channel has a length of 0.5~1.5mm.
4. The preparation method according to claim 3, characterized in that, Both the large-scale and small-scale traps have isosceles triangular internal folds with a constant apex angle on their inner walls, forming a tortuous interface through local excision; wherein the apex angle is 1~5°.
5. The preparation method according to claim 1, characterized in that, The configuration of the three-dimensional carrier is selected from at least one of SC lattice, DSHG lattice, DLHG lattice, SLHG lattice and LTAG lattice.
6. The preparation method according to claim 1, characterized in that, In step 2, the specific method of the oxidation etching treatment is as follows: the three-dimensional carrier is immersed in a mixed solution of oxidant and alkaline regulator at 20~80℃ for 40~100min, and then dried; wherein, the oxidant is selected from at least one of sodium persulfate, potassium persulfate, potassium permanganate, potassium dichromate, chromic anhydride, hydrogen peroxide, sodium hypochlorite, ammonium persulfate, and ammonium persulfate-ferrous sulfate composite system, with a concentration of 0.01~1M; the alkaline regulator is selected from at least one of sodium hydroxide, potassium hydroxide, lithium hydroxide, cesium hydroxide, potassium carbonate, sodium carbonate, sodium bicarbonate, and tetramethylammonium hydroxide, with a concentration of 1~5M.
7. The preparation method according to claim 1, characterized in that, In step 2, the acidic coordination treatment specifically involves immersing the oxidized and etched three-dimensional carrier in a coordination agent solution at 20-100°C for 40-100 minutes, then removing and drying it. The coordination agent is selected from at least one of malonic acid, succinic acid, phthalic acid, pyromellitic acid, squaric acid, citric acid, tartaric acid, disodium EDTA, salicylic acid, terephthalic acid, and maleic acid, and its concentration is 0.1-1.0 M.
8. The preparation method according to claim 1, characterized in that, In step 2, the alkaline reduction treatment specifically involves immersing the acid-coordinated three-dimensional carrier in a mixed solution containing a reducing agent and an alkaline regulator for 10-60 minutes.
9. A photothermal-driven, strong-weak convection coupled electrode for nitrite ammonia production, characterized in that, It is prepared by the preparation method according to any one of claims 1 to 8.
10. The nitrite-to-ammonia electrode as described in claim 9, characterized in that, The electrode comprises a three-dimensional carrier, a pure copper conductive layer, and a copper-based heterojunction catalytic layer; the three-dimensional carrier has a dual-scale asymmetric trap unit structure; the copper-based heterojunction catalytic layer is a multi-anion-doped copper-based heterojunction composed of crystalline copper, crystalline cuprous oxide, and amorphous copper organic complexes.