Preparation method of anti-scaling cathode with long-life hydrophobic coating
By constructing a multi-level microcone array structure and a hydrophobic coating on the cathode surface, the cathode scaling problem was solved, achieving a long-life anti-scaling effect and maintaining the stability and efficiency of the electrolysis process.
Patent Information
- Application Number
- CN202511340026.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-19
- Publication Date
- 2026-01-30
AI Technical Summary
In existing technologies, cathode scaling increases the resistance to interfacial charge transfer during electrochemical treatment of saline water, affecting the stability and efficiency of the electrolysis reaction. Furthermore, existing hydrophobic coatings are prone to failure during continuous operation, failing to achieve long-life anti-scaling effects.
By constructing a multi-level microcone array structure and combining it with a hydrophobic intermediate layer and a self-healing coating, an anti-scaling cathode with a long-life hydrophobic coating was prepared. By using a micron-level tin cone array and a nano-level nickel-iron microcone array combined with a hydrophobic coating, a stable hydrophobic coating was formed to block the adhesion of crystals such as calcium carbonate.
It significantly enhances the stability and service life of the hydrophobic layer on the cathode surface, effectively blocks the adhesion of crystals such as calcium carbonate, extends the durability and anti-scaling properties of the cathode, and maintains the stability and efficiency of the electrolysis process.
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Figure CN121428591A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of electrode technology and relates to a method for preparing an anti-scaling cathode with a long-life hydrophobic coating. Background Technology
[0002] Electrochemical technology utilizes clean and renewable energy to drive chemical reactions, offering advantages such as being green and low-carbon, requiring no chemical reagents, and being highly controllable. It shows promise in brine treatment fields such as seawater hydrogen production, seawater uranium extraction, brine lake lithium extraction, brackish water desalination, circulating cooling water softening, and heavy metal recovery from industrial wastewater. During the brine electrolysis process, a large amount of OH- is generated on the cathode surface. - This leads to a significant increase in pH near the cathode, and the Ca in the solution... 2+ and Mg 2+ With the generated OH - The reaction produces insulating CaCO3 and Mg(OH)2, which deposit on the cathode surface, causing cathode scaling. To ensure continuous and stable operation of the brine electrolysis reaction, the allowable upper limits for calcium and magnesium ions are Ca2+, Ca2+, and Mg2+, respectively. 2+ ≤0.01 mol / L, Mg 2+ ≤0.1 mol / L. However, the actual calcium and magnesium concentrations in saline water are usually much higher than these values; for example, the calcium concentration in natural seawater is often much higher than these values. 2+ and Mg 2+ The concentrations are approximately 0.42 g / L and 1.33 g / L, respectively. Therefore, cathode scaling is inevitable in the electrochemical treatment of actual saline solutions. As the reaction time increases, the insulating scale layer deposited on the cathode surface becomes thicker, and the resistance to interfacial charge transfer continuously increases. Under constant voltage, after 48 hours of operation, the current density loss of a conventional cathode reaches over 57%. Therefore, cathode scaling has become a bottleneck limiting the application of direct electrolysis of saline solutions.
[0003] Currently, there are few reports on preventing cathode scaling, both domestically and internationally. The reference "A membrane-based seawater electrolyser for hydrogen generation" reports a phase change membrane that converts seawater in situ into pure water for electrolysis through a phase change migration mechanism. However, the wetting problem of hydrophobic phase change membranes severely restricts the development of this method. Furthermore, the reference "Solidophobic surface for electrochemical extraction of high-valued Mg(OH)2 coupled with H2 production from seawater" reports the introduction of a hydration layer on the cathode surface to prevent contact between the electrode and Mg(OH)2, thus avoiding scale buildup on the electrode surface. However, the hydration layer method mainly focuses on optimizing the microenvironment of the electrode surface, and its isolation effect on ions in the brine is not as direct as that of a membrane. Additionally, the reference "In situ ammonium formation mediates efficient hydrogen production from natural seawater splitting" reports that the cathode can generate NH4 in situ. + Capture OH - This prevents the solution pH from rising and avoids scale crystal nucleation in the solution. However, NH4 + OH - Surface trapping exacerbates scale nucleation on the electrode surface. Furthermore, the reference "Visualization of crystal automatic exfoliation on an anti-scaling cathode with well-ordered hydrophobic microcones" describes a mechanism for automatic scale removal by designing the cathode as a copper nanotip structure with a hydrophobic surface. However, due to the use of dodecyl mercaptan to modify the nanotip, this surface-modified hydrophobicity easily disappears during continuous operation, resulting in poor stability of this electrode.
[0004] The methods described above have made some contributions to the research on anti-scaling of cathodes, but the problem of short-term anti-scaling effect still exists. Obviously, to completely solve this problem, it is necessary to develop a long-life cathode that can achieve automatic scale removal. Summary of the Invention
[0005] The purpose of this invention is to provide a method for preparing an anti-scaling cathode with a long-life hydrophobic coating.
[0006] The technical solution of the present invention:
[0007] A method for preparing an anti-scaling cathode with a long-life hydrophobic coating, comprising the following steps:
[0008] (1) Pretreatment of metal wire mesh: Place the metal wire mesh in a sulfuric acid solution with a mass fraction of 1-30% for 5-60 min, then take it out and clean it with anhydrous ethanol. After that, store it in anhydrous ethanol for later use.
[0009] (2) Construction of micron-scale tin cone array: Under isothermal conditions of 1-90 °C, using an aqueous solution of tin salt, buffer and surfactant as electrolyte, and a current density of 1-200 mA / cm², the array was constructed. 2 The reaction time is 1-300 min to create a micron-sized tin cone array on the surface of the metal wire mesh; then it is stored in anhydrous ethanol for later use.
[0010] (3) Construction of nanoscale nickel-iron microcone arrays: Under isothermal conditions of 1-90 °C, using an aqueous solution of nickel salt, iron salt, crystal plane protectant and buffer as electrolyte, and a current density of 1-200 mA / cm², 2 The reaction time is 1-300 min to cover the surface of the metal wire mesh with the micron-sized tin cone array with the nano-sized nickel-iron binary alloy micro cone array; then it is stored in anhydrous ethanol for later use.
[0011] (4) Construction of hydrophobic intermediate layer: Prepare hydrophobic coating containing hydrophobic reagent and dispersant in ethyl acetate. Apply the hydrophobic coating evenly to a metal wire mesh containing a nanoscale nickel-iron binary alloy microcone array by spin coating. Heat cure at 80-130 ℃ for 1-600 min to obtain a hydrophobic coating with strong adhesion.
[0012] (5) Construction of self-healing hydrophobic layer: Prepare hydrophobic coating containing hydrophobic reagent, dispersant and binder in ethyl acetate. Apply the hydrophobic coating evenly to the hydrophobic coating by spin coating. Heat cure at 40-100 ℃ for 1-300 min to obtain anti-scaling cathode.
[0013] In step (1), the material of the metal wire mesh includes, but is not limited to, stainless steel, iron, titanium, copper, nickel and other metal elements and their alloys.
[0014] In step (2), the tin salt includes, but is not limited to, stannous chloride, stannous sulfate, stannous methanesulfonate, stannous pyrophosphate, etc., and the buffer includes, but is not limited to, acidic solutions such as acetic acid, hydrochloric acid, phosphoric acid, sulfuric acid, etc., with a buffer concentration of 0.01-5 mol / L. The surfactant includes, but is not limited to, organic substances such as Tween-20, Tween-40, Tween-80, Triton X-114, Triton X-100, etc.
[0015] In step (2), the mass fraction ratio of tin salt, buffer and surfactant is (1-60%): (1-50%): (0.1-30%).
[0016] In step (3), the nickel salt includes, but is not limited to, nickel sulfate, nickel chloride, nickel acetate, nickel aminosulfonate, nickel hypophosphite, etc., the iron salt includes, but is not limited to, ferrous chloride, ferrous sulfate, ferrous nitrate, ferrous acetate, etc., the crystal surface protectant includes, but is not limited to, calcium chloride, sodium chloride, magnesium chloride, potassium chloride, etc., and the buffer includes, but is not limited to, acetic acid, hydrochloric acid, ammonia, potassium hydroxide, etc., and the buffer concentration is 0.01-5 mol / L.
[0017] In step (3), the mass fraction ratio of nickel salt, iron salt, crystal surface protectant and buffer is (1-40%): (0.1-15%): (1-20%): (0.01-10%).
[0018] In step (4), the hydrophobic reagent includes, but is not limited to, polytetrafluoroethylene, dodecyl mercaptan, polydimethylsiloxane, paraffin, etc., and the dispersant includes, but is not limited to, methanol, ethanol, acetone, etc.
[0019] In step (4), the mass fraction ratio of the hydrophobic reagent to the dispersant is (1-70%): (0.01-30%).
[0020] In step (5), the hydrophobic agent includes, but is not limited to, polyurethane, perfluoropolyether diol, trifluoropropylmethylcyclotrisiloxane, epoxy resin, etc., the dispersant includes, but is not limited to, methanol, ethanol, acetone, etc., and the binder includes, but is not limited to, vinyltriamine, diaminocyclohexane, diethylenetriamine, dibenzylamine ether, etc.
[0021] In step (5), the mass fraction ratio of the hydrophobic reagent, dispersant and binder is (1-30%): (0.01-5%): (0.1-50%).
[0022] The beneficial effects of this invention are as follows: By constructing a multi-level microcone array structure and combining it with a hydrophobic intermediate layer and a self-healing coating, this invention significantly enhances the stability and service life of the hydrophobic layer on the cathode surface. This composite coating system can maintain its hydrophobic properties for a long time during electrolysis, effectively preventing the adhesion of crystals such as calcium carbonate to the surface. Even after long-term operation, the coating can still maintain its integrity and hydrophobic function, delaying scaling caused by coating failure, thereby improving the durability and anti-scaling persistence of the cathode under real high-hardness water conditions. This invention requires no chemical dosing, does not increase operational complexity, and does not interrupt the electrolysis process, offering advantages such as simple operation and maintenance, high energy efficiency, and environmental friendliness. Attached Figure Description
[0023] Figure 1 This is a schematic diagram illustrating the preparation of the anti-scaling cathode of the present invention.
[0024] Figure 2 This is a flowchart of the preparation process of the present invention.
[0025] Figure 3 This is a scanning electron microscope image of an anti-fouling electrode with a long-life hydrophobic coating.
[0026] Figure 4 This is a scanning electron microscope image of an anti-scaling electrode with a long-life hydrophobic coating after a hydrophobic layer lifetime test.
[0027] Figure 5 The graphs show the changes in the hydrophobic angle of the anti-scaling electrode with a long-life hydrophobic coating before (a) and after (b) the hydrophobic layer life test experiment.
[0028] Figure 6 This is a scanning electron microscope image of the morphology of the prepared electrode. Detailed Implementation
[0029] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and technical solutions.
[0030] Example 1
[0031] (1) A 40-mesh commercial nickel mesh was used as the substrate. All solutions in the experiment were prepared using analytical grade chemicals and ultrapure water. Before electrodeposition, the nickel mesh was first sonicated in 10% H2SO4 solution for 15 minutes to remove surface contaminants and oxides, then rinsed with ethanol and ultrapure water and stored in anhydrous ethanol.
[0032] (2) The first step of electrodeposition was carried out in a two-electrode electrochemical system. The electrodeposition solution contained stannous chloride, phosphoric acid, and Tween-80, with concentrations of 0.25 mol / L, 0.03 mol / L, and 0.005 mol / L, respectively. The electrodeposition temperature was 35 ℃, and the current density was 75 mA / cm². 2 Electrodeposition for 5 min. After deposition, remove the sample from the electrolyte, rinse thoroughly with water and ethanol, and store in anhydrous ethanol.
[0033] (3) The second electrodeposition step was carried out in a two-electrode chemical system. The electrodeposition solution contained nickel sulfate, ferrous sulfate, sulfuric acid, and calcium chloride, with concentrations of 0.5 mol / L, 0.08 mol / L, 0.007 mol / L, and 0.9 mol / L, respectively. The electrodeposition temperature was 45 ℃, and the current density was 50 mA / cm². 2 Electrodeposition for 10 min. After deposition, remove the sample from the electrolyte, rinse thoroughly with water and ethanol, and store in anhydrous ethanol.
[0034] (4) Polytetrafluoroethylene and acetone were selected as hydrophobic reagents and dispersants, with contents of 5 g / L and 1 g / L, respectively, to prepare an inert coating. The inert coating was uniformly coated onto the material containing the multi-level microcone array by spin coating, and then heat-cured at 80 °C for 90 min and stored at room temperature.
[0035] (5) Epoxy resin, methanol, and vinyltriamine were selected as hydrophobic reagents, dispersants, and binders, with contents of 20 g / L, 7.5 g / L, and 5 g / L, respectively, to prepare a hydrophobic coating. The hydrophobic coating was uniformly coated onto a material containing a multi-level microcone array by spin coating and thermo-cured at 60 ℃ for 100 min. The morphology of the prepared anti-scaling electrode is shown in the figure. Figure 3 .
[0036] Electrode hydrophobic layer lifetime testing was conducted in an electrochemical reactor. The anode and cathode used RuO2-IrO2-TiO2 / Ti mesh and an anti-scaling electrode, respectively. A 0.05 M sodium sulfate solution was prepared as the electrolyte. The electrolyte was tested at 100 mA / cm². 2 The reaction was carried out at a constant current density for 10 h. The experimental results are shown in Table 1. After the reaction, the hydrophobic layer on the electrode surface did not rupture, and the microstructure was as follows. Figure 4 As shown. The hydrophobic angle of the electrode surface did not decrease significantly before and after the reaction, as... Figure 5 As shown.
[0037] Electrode scale inhibition experiments were conducted in an electrochemical reaction tank. The anode and cathode used RuO2-IrO2-TiO2 / Ti mesh and anti-scaling electrodes, respectively. A solution containing 400 mg / L Ca was prepared. 2+ 360 mg / L HCO3 - An aqueous solution was used as the electrolyte. A DC power supply of 2 mA / cm² was applied during the reaction. 2 A constant current density was applied, and the reaction time was 40 min. The experimental results are shown in Table 2:
[0038] Table 1. Comparison of hydrophobic layer lifespan between paraffin electrodes and anti-scaling electrodes
[0039]
[0040] Table 2. Performance of Anti-scaling Electrodes
[0041]
[0042] Example 2
[0043] (1) The substrate is stainless steel mesh, the H2SO4 content is 1%, and the ultrasonic time is 30 min. The remaining conditions and steps are the same as those in step (1) of Example 1.
[0044] (2) The electrodeposition solution contained stannous sulfate, sulfuric acid, and Tween-20, with concentrations of 0.15 mol / L, 0.04 mol / L, and 0.003 mol / L, respectively. The electrodeposition temperature was 45 ℃, and the current density was 5 mA / cm². 2 Electrodeposition for 250 min. All other conditions and steps are the same as step (2) in Example 1.
[0045] (3) The electrodeposition solution contains nickel chloride, ferrous chloride, hydrochloric acid, and sodium chloride, with concentrations of 0.8 mol / L, 0.1 mol / L, 0.005 mol / L, and 1.5 mol / L, respectively. The electrodeposition temperature is 70 ℃, and the current density is 10 mA / cm². 2 Electrodeposition for 90 min. All other conditions and steps are the same as step (3) in Example 1.
[0046] (4) Dodecanethiol and ethanol were selected as hydrophobic reagents and dispersants, with contents of 3 g / L and 0.7 g / L, respectively, to prepare an inert coating. The inert coating was uniformly coated onto the material containing the multi-level microcone array by spin coating and heat-cured at 130 °C for 550 min. The remaining conditions and steps were the same as step (4) in Example 1.
[0047] (5) Polyurethane, methanol, and diaminocyclohexane were selected as hydrophobic reagents, dispersants, and binders, with contents of 10 g / L, 1 g / L, and 5 g / L, respectively, to prepare a hydrophobic coating. The hydrophobic coating was uniformly coated onto a material containing a multi-level microcone array by spin coating and thermo-cured at 40 ℃ for 300 min to prepare an anti-scaling electrode.
[0048] Example 2
[0049] (1) The substrate is iron mesh, the H2SO4 solution concentration is 30%, and the ultrasonic time is 5 min. The remaining conditions and steps are the same as those in step (1) of Example 1.
[0050] (2) The electrodeposition solution contained stannous sulfate, sulfuric acid, and Triton X-100, with concentrations of 0.5 mol / L, 0.4 mol / L, and 0.3 mol / L, respectively. The electrodeposition temperature was 5 ℃, and the current density was 200 mA / cm². 2 Electrodeposition for 10 min. All other conditions and steps are the same as step (2) in Example 1.
[0051] (3) The electrodeposition solution contained nickel acetate, ferrous acetate, acetic acid, and calcium chloride, with concentrations of 1.5 mol / L, 0.09 mol / L, 0.005 mol / L, and 0.5 mol / L, respectively. The electrodeposition temperature was 90 ℃, and the current density was 5 mA / cm².2 Electrodeposition for 10 min. All other conditions and steps are the same as step (3) in Example 1.
[0052] (4) Polydimethylsiloxane and methanol were selected as hydrophobic reagent and dispersant, respectively, with contents of 20 g / L and 5 g / L, to prepare an inert coating. The inert coating was uniformly coated onto the material containing the multi-level microcone array by spin coating and heat-cured at 80 °C for 600 min. The remaining conditions and steps were the same as step (4) of Example 1.
[0053] (5) Perfluoropolyether diol, acetone, and dibis(benzyl)amino ether were selected as hydrophobic reagents, dispersants, and binders, with contents of 20 g / L, 1 g / L, and 15 g / L, respectively, to prepare a hydrophobic coating. The hydrophobic coating was uniformly coated onto a material containing a multi-level microcone array by spin coating and then heat-cured at 100 °C for 30 min to prepare an anti-scaling electrode.
[0054] Example 3
[0055] (1) The substrate is a titanium mesh, the H2SO4 solution concentration is 20%, and the ultrasonic time is 20 min. The remaining conditions and steps are the same as those in step (1) of Example 1.
[0056] (2) The electrodeposition solution contained stannous pyrophosphate, phosphoric acid, and Triton X-114, with concentrations of 1.5 mol / L, 0.1 mol / L, and 0.1 mol / L, respectively. The electrodeposition temperature was 80 ℃, and the current density was 100 mA / cm². 2 Electrodeposition for 150 min. All other conditions and steps are the same as step (2) in Example 1.
[0057] (3) The electrodeposition solution contained hypophosphite, ferrous nitrate, ammonia, and magnesium chloride, with concentrations of 3.5 mol / L, 0.01 mol / L, 0.08 mol / L, and 0.15 mol / L, respectively. The electrodeposition temperature was 20 ℃, and the current density was 100 mA / cm². 2 Electrodeposition for 80 min. All other conditions and steps are the same as step (3) in Example 1.
[0058] (4) Paraffin wax and acetone were selected as hydrophobic reagent and dispersant, respectively, with contents of 40 g / L and 0.2 g / L, to prepare an inert coating. The inert coating was uniformly coated onto the material containing the multi-level microcone array by spin coating and heat-cured at 110 °C for 30 min. The remaining conditions and steps were the same as step (4) of Example 1.
[0059] (5) Trifluoropropylmethylcyclotrisiloxane, methanol, and diethylenetriamine were selected as hydrophobic reagents, dispersants, and binders, with contents of 2 g / L, 0.1 g / L, and 1 g / L, respectively, to prepare a hydrophobic coating. The hydrophobic coating was uniformly coated onto a material containing a multi-level microcone array by spin coating and thermosetting at 70 °C for 100 min to prepare an anti-scaling electrode.
[0060] Comparative Example 1
[0061] Step (4) is omitted; the other steps are the same as steps (1), (2), (3), and (5) in Example 1. The morphology of the prepared electrode is as follows. Figure 6 As shown in Table 3, the electrode was subjected to a scale inhibition experiment, with the specific operation and conditions being the same as in Example 1. The scale inhibition rate of the electrode prepared in Example 1 was significantly higher than that in Comparative Example 1, indicating a significant anti-scaling effect.
[0062] Table 3
[0063] .
Claims
1. A method for the production of an anti-fouling cathode with a long- life hydrophobic coating, characterized in that, The steps are as follows: (1) Pretreatment of the metal mesh: place the metal mesh in a 1-30% sulfuric acid solution for 5-60 minutes, then clean it with anhydrous ethanol, and store it in anhydrous ethanol for later use; (2) Construction of micrometer-sized tin cone array: under the constant temperature condition of 1-90 ℃, using the water solution mixed by tin salt, buffer and surfactant as electrolyte, reacting 1-300 min under the current density of 1-200 mA / cm 2 to make the metal wire mesh surface with micrometer-sized tin cone array; Then store it in anhydrous ethanol for later use; (3) Construction of nanoscale nickel-iron microcone array: under constant temperature conditions of 1-90 ℃, using the aqueous solution of mixed nickel salt, iron salt, crystal face protective agent and buffer as electrolyte, and under the conditions of current density of 1-200 mA / cm 2 2> reacting for 1-300 min, so that the surface of the metal wire mesh with microscale tin cone array is covered with nanoscale nickel-iron binary alloy microcone array; Then store it in anhydrous ethanol for later use; (4) Construction of the hydrophobic intermediate layer: in ethyl acetate, prepare a hydrophobic coating containing a hydrophobic reagent and a dispersant, uniformly coat the hydrophobic coating onto the metal mesh containing the nano-scale nickel-iron binary alloy micro-cone array using a spin coating method, and heat cure at a temperature of 80-130°C for 1-600 minutes to obtain a strong adhesion hydrophobic coating; (5) Construction of the self-healing hydrophobic layer: in ethyl acetate, prepare a hydrophobic coating containing a hydrophobic reagent, a dispersant, and a binder, uniformly coat the hydrophobic coating onto the hydrophobic coating using a spin coating method, and heat cure at a temperature of 40-100°C for 1-300 minutes to obtain an anti-fouling cathode.
2. The preparation method of the anti-fouling cathode with a long-life hydrophobic coating according to claim 1, characterized in that, in step (1), The material of the metal mesh includes stainless steel, iron, titanium, copper, nickel, and their alloys.
3. The preparation method of the anti-fouling cathode with a long-life hydrophobic coating according to claim 1, characterized in that, in step (2), The tin salt is stannous chloride, stannous sulfate, stannous methylsulfonate, or stannous pyrophosphate; The buffer is acetic acid, hydrochloric acid, phosphoric acid, or sulfuric acid, with a concentration of 0.01-5 mol / L; The surfactant is Tween-20, Tween-40, Tween-80, Triton X-114, or Triton X-100; The mass fraction ratio of the tin salt, the buffer, and the surfactant is (1-60%):(1-50%):(0.1-30%).
4. The preparation method of the anti-fouling cathode with a long-life hydrophobic coating according to claim 1, characterized in that, in step (3), The nickel salt is nickel sulfate, nickel chloride, nickel acetate, nickel sulfamate, or nickel hypophosphite; The iron salt is ferrous chloride, ferrous sulfate, ferrous nitrate, or ferrous acetate; The crystal face protective agent is calcium chloride, sodium chloride, magnesium chloride, or potassium chloride; The buffer is acetic acid, hydrochloric acid, ammonia, or potassium hydroxide, with a concentration of 0.01-5 mol / L; The mass fraction ratio of the nickel salt, the iron salt, the crystal face protective agent, and the buffer is (1-40%):(0.1-15%):(1-20%):(0.01-10%).
5. The preparation method of the anti-fouling cathode with a long-life hydrophobic coating according to claim 1, characterized in that, in step (4), The hydrophobic reagent is polytetrafluoroethylene, dodecanethiol, polydimethylsiloxane, or paraffin; The dispersant is methanol, ethanol, or acetone; The mass fraction ratio of the hydrophobic reagent and the dispersant is (1-70%):(0.01-30%).
6. The preparation method of the anti-fouling cathode with a long-life hydrophobic coating according to claim 1, characterized in that, in step (5), The hydrophobic reagent is polyurethane, perfluoropolyether diol, trifluoropropylmethylcyclotrisiloxane, or epoxy resin; The dispersant is methanol, ethanol or acetone; The binder is vinyl triamine, diaminocyclohexane or diethylenetriamine; The mass ratio of the hydrophobic agent, the dispersant and the binder is (1-30%): (0.01-5%): (0.1-50%).