Titanium-based catalytic electrode and method for manufacturing the same

Abstract

This invention discloses a titanium-based catalytic electrode and its preparation method, comprising steps such as substrate pretreatment, hydrothermal preparation, and CV doping. Through the above method, the titanium-based catalytic electrode and its preparation method of this invention, using a titanium mesh as a substrate, constructs a titanium-based metal electrode through a multi-step sequential preparation process including substrate etching, hydrothermal treatment, and electrochemical doping. This not only effectively enhances the local pH of the cathode and promotes the rapid precipitation of Mg(OH)2, but also inhibits the dense adhesion of calcium and magnesium scale, extending the electrode's self-cleaning cycle. It is suitable for treating high-hardness wastewater under alkaline conditions, providing important technical support for water pollution control, recycling, and the implementation of sustainable development strategies, possessing significant scientific value and promising application prospects.

Description

Technical Field

[0001] This invention relates to the field of electrochemical industrial water treatment technology, and in particular to a titanium-based catalytic electrode and its preparation method. Background Technology

[0002] Driven by the global transition to clean and low-carbon energy, water pollution control and recycling have become core tasks for ecological and environmental protection. Electrochemical water treatment technology, with its advantages of being chemical-free or requiring minimal chemical dosage, being environmentally friendly, and ensuring thorough degradation, has become a key pathway for treating high-salt, high-hardness, and recalcitrant industrial wastewater, showing broad application prospects in areas such as advanced industrial wastewater treatment and hardness removal in circulating water systems. The cathode, as the core reaction unit of this system, directly determines key indicators such as calcium and magnesium ion removal and hydrogen evolution efficiency through material selection and performance optimization, and is crucial for improving system efficiency and reducing energy consumption.

[0003] Titanium-based materials, due to their abundant reserves, strong corrosion resistance, excellent mechanical properties, and good compatibility with catalytic components, have become the preferred substrate for electrochemical water treatment cathodes. Compared with traditional graphite and stainless steel cathodes, they can effectively avoid corrosion and passivation, extending their service life. Through strategies such as metal loading and doping modification, the electronic structure and surface properties of titanium-based cathodes can be controlled. Among them, titanium-based catalytic cathodes loaded with non-precious metals such as iron and aluminum combine cost advantages with catalytic potential, making them suitable for core requirements such as hardening and flocculation. Furthermore, their preparation processes are flexible; low-cost methods such as electrodeposition and hydrothermal synthesis can achieve efficient loading, providing a foundation for large-scale application and overcoming the pain points of high cost and short lifespan of traditional cathodes.

[0004] However, current titanium-based cathodes still face significant bottlenecks: First, their intrinsic catalytic activity is insufficient, and the efficiency of hydrogen evolution and calcium-magnesium electrodeposition at high current densities is insufficient to meet the treatment requirements of high-concentration wastewater. Second, their stability is poor; in high-hardness environments, the metal support layer is prone to detachment and scaling, leading to activity degradation. Third, their electron conduction efficiency is low, increasing energy consumption. Fourth, their modification strategies are imperfect, resulting in poor dispersion and binding of active components and insufficient adaptability. Therefore, developing low-cost, high-activity titanium-based cathode modification technologies to address these bottlenecks is a core issue for promoting the large-scale implementation of electrochemical water treatment technologies. Summary of the Invention

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0006] A method for preparing a titanium-based catalytic electrode is provided, the steps of which include:

[0007] S1. Substrate pretreatment: First, the titanium substrate is placed in a heated pickling solution. The pickling solution cleans, etches, and activates the surface of the titanium substrate, effectively removing surface oil and natural oxide layers to increase surface roughness and specific surface area.

[0008] S2. Hydrothermal preparation: Soluble iron salts and aluminum salts are mixed with ultrapure water and stirred until completely dissolved. The mixture is then heated to 40-80℃ to prepare a mixed iron-aluminum solution. The concentration of iron salts in the mixed iron-aluminum solution is 0.2-1M, and the concentration of aluminum salts is 0.2-1M. This mixed iron-aluminum solution is used as the hydrothermal solution. The hydrothermal solution and the pretreated titanium substrate are placed in a reactor for hydrothermal reaction at a temperature of 120℃-180℃ for 6-12 hours. After cooling to room temperature, the substrate is removed, rinsed, and dried for later use to obtain the Fe-Al / Ti electrode.

[0009] S3, CV doping: Soluble nickel salt and zinc salt are mixed with ultrapure water and stirred until completely dissolved, then heated to 40-80℃ to prepare a mixed nickel-zinc solution. The concentration of nickel salt in the mixed nickel-zinc solution is 0.05-0.5M, and the concentration of zinc salt is 0.05-0.5M. The mixed nickel-zinc solution is used as the deposition solution. The Fe-Al / Ti electrode is placed in the deposition solution, and electrochemical deposition is performed using cyclic voltammetry. Nickel and zinc metals are doped on the Fe-Al / Ti electrode deposition layer to further improve the catalytic activity and stability of the electrode. Zinc element plays a role in regulating the electrode surface as an auxiliary metal, thereby obtaining a titanium-based catalytic electrode.

[0010] In a preferred embodiment of the present invention, the titanium substrate is a titanium mesh.

[0011] In a preferred embodiment of the present invention, in step S1, the pickling solution includes citric acid, ascorbic acid, or acetic acid.

[0012] In a preferred embodiment of the present invention, in step S1, a 10 cm * 10 cm titanium mesh substrate is placed in a 0.01-0.1 M oxalic acid solution, and the titanium substrate is placed in an oxalic acid solution at 60℃-80℃ for 50 minutes and then removed; after washing with ethanol and ultrapure water multiple times, it is placed in a 60℃ oven to dry for later use.

[0013] In a preferred embodiment of the present invention, in step S2, the soluble iron salt includes one or more of ferric chloride, ferric nitrate, ferric sulfate, ferrous sulfate, and ferrous chloride; wherein the concentration of the iron salt in the hydrothermal solution is 0.5M.

[0014] In a preferred embodiment of the present invention, in step S2, the soluble aluminum salt includes one of aluminum nitrate, alum, aluminum sulfate, and aluminum chloride; wherein the concentration of the aluminum salt in the hydrothermal solution is 0.5M.

[0015] In a preferred embodiment of the present invention, in step S3, the soluble nickel salt includes one of nickel chloride, nickel nitrate, and nickel sulfate; wherein the concentration of the nickel salt in the precipitation solution is 0.1M.

[0016] In a preferred embodiment of the present invention, in step S3, the soluble zinc salt includes one of zinc chloride, zinc nitrate, and zinc sulfate; wherein the concentration of the zinc salt in the precipitate is 0.1M.

[0017] In a preferred embodiment of the present invention, in step S3, during electrochemical deposition, the activation voltage range is set to -0.6V to 1.8V, the scan rate is 3mV / s, and the number of scans is 8.

[0018] A water treatment cathode electrode comprising a titanium-based catalytic electrode prepared by any of the above methods, for removing calcium and magnesium ions from industrial water and reducing the total hardness of industrial water.

[0019] The beneficial effects of this invention are as follows: by using a titanium mesh as a substrate and constructing a titanium-based metal electrode through a multi-step sequential preparation process including substrate etching, hydrothermal treatment, and electrochemical doping, it not only effectively enhances the local pH of the cathode and promotes the rapid precipitation of Mg(OH)2, but also inhibits the dense adhesion of calcium and magnesium scale, extends the self-cleaning cycle of the electrode, and is suitable for the treatment of high-hardness wastewater under alkaline conditions. It plays an important supporting role in promoting water pollution control, resource recycling, and sustainable development strategies, and has outstanding scientific value and broad application prospects. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, wherein:

[0021] Figure 1 This is a SEM image of the catalyst obtained in Example 1 of the titanium-based catalytic electrode and its preparation method of the present invention. Detailed Implementation

[0022] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] Please see Figure 1 The embodiments of the present invention include:

[0024] Example 1

[0025] A method for preparing a titanium-based catalytic electrode, comprising the following steps:

[0026] 1) Substrate Pretreatment (Ti): A 10 cm * 10 cm titanium mesh substrate was placed in a 0.05 M oxalic acid solution and immersed in the oxalic acid solution at 70 °C for 50 min. Afterward, it was removed and washed multiple times with ethanol and ultrapure water before being dried in a 60 °C oven for later use. Under heating conditions, the oxalic acid solution can clean, etch, and activate the surface of the titanium mesh, effectively removing surface oil and natural oxide layers, increasing surface roughness and specific surface area, and improving the bonding strength between the titanium mesh and the subsequently supported catalytic materials, thus providing a good surface foundation for the preparation of high-performance titanium-based catalytic electrodes.

[0027] 2) Hydrothermal preparation (Fe-Al / Ti): Soluble iron salt and aluminum salt are mixed with ultrapure water and stirred until completely dissolved. The mixture is then heated to 60°C to prepare a mixed iron-aluminum solution containing 0.5M and 0.5M, which serves as the hydrothermal solution. The hydrothermal solution and the treated titanium mesh are placed in a reactor for hydrothermal reaction at 150°C for 9 hours. After cooling to room temperature, the mesh is removed, rinsed, and dried for later use to obtain the Fe-Al / Ti electrode.

[0028] 3) CV Doping (Ni-Zn / Fe-Al / Ti): Soluble nickel and zinc salts were mixed with ultrapure water and stirred until completely dissolved. The mixture was then heated to 60°C to prepare a mixed nickel-zinc solution containing 0.1M and 0.1M solutions, which served as the deposition solution. The Fe-Al / Ti electrode was placed in the deposition solution, and electrochemical deposition was performed using cyclic voltammetry. Nickel and zinc metals were doped onto the Fe-Al / Ti electrode deposition layer to further enhance the catalytic activity and stability of the electrode. Zinc also served as an auxiliary metal to regulate the electrode surface. The deposition voltage range was set to -0.6V to 1.8V, the scan rate was 3mV / s, and the number of scan cycles was 8.

[0029] Using titanium mesh as the substrate material, metallic iron and aluminum are loaded onto the surface of the titanium mesh via a hydrothermal synthesis method. Utilizing the high temperature and high pressure environment of the hydrothermal reaction, the iron and aluminum components grow in situ on the titanium mesh surface to form a uniform and dense load layer, constructing a stable composite carrier structure. Subsequently, a small amount of metallic nickel and zinc are doped onto this iron-aluminum composite carrier using an electrochemical deposition method, ultimately preparing a titanium mesh-based multi-metal composite electrode. This electrode is then used as a cathode in the electrochemical treatment of industrial water, specifically for removing calcium and magnesium ions and reducing the total hardness of industrial water.

[0030] Hydrothermally loaded iron and aluminum can fully leverage their synergistic flocculation and co-precipitation effects, providing ample active sites for the efficient removal of calcium and magnesium ions. Simultaneously, the titanium mesh substrate possesses excellent corrosion resistance and mechanical stability, effectively avoiding the corrosion and passivation problems of traditional cathode materials during long-term operation. Electrochemical doping with small amounts of nickel and zinc further modulates the electronic states of the electrode surface and optimizes interfacial electron transport efficiency, significantly improving the electrodeposition efficiency and reaction selectivity for calcium and magnesium ions. This effectively addresses the shortcomings of traditional iron-aluminum loaded titanium-based electrodes, such as limited active sites, insufficient electron conduction, and weak calcium and magnesium precipitation adhesion. Furthermore, the titanium mesh substrate, as a support, effectively fixes the active components of iron, aluminum, nickel, and zinc, solving the stability problems caused by oxide layer detachment and grain growth in loaded metal layers. This allows the composite cathode to exhibit excellent catalytic activity and structural stability in high-hardness, high-salt industrial water systems, providing a novel cathode solution for the low-cost, large-scale application of electrochemical water treatment technology to efficiently remove calcium and magnesium ions, reduce the total hardness of industrial water, and achieve industrial wastewater softening.

[0031] In summary, this electrode, fabricated through a multi-step sequential process involving substrate cleaning and etching, hydrothermal treatment, and electrochemical doping to construct a titanium-based metal electrode, effectively enhances the local pH of the cathode, promotes rapid precipitation of Mg(OH)₂, inhibits dense adhesion of calcium and magnesium scale, and extends the electrode's self-cleaning cycle. Furthermore, the iron-aluminum metal coupling provides ample active sites for the efficient removal of calcium and magnesium ions. Electrochemical doping with nickel and zinc further modulates the electronic states on the electrode surface and optimizes interfacial electron transport efficiency, significantly improving the electrodeposition efficiency and reaction selectivity for calcium and magnesium ions. Experimental results demonstrate that the synthesized electrode exhibits excellent catalytic activity and structural stability in industrial water treatment. This system provides a novel cathode solution for low-cost, large-scale application in industrial wastewater softening.

[0032] Comparative Example 1

[0033] A 10 cm * 10 cm titanium mesh substrate was placed in a 0.05 M oxalic acid solution. The titanium mesh substrate was then immersed in the oxalic acid solution at 70 °C for 50 min and then removed. After washing it multiple times with ethanol and ultrapure water, it was dried in a 60 °C oven to obtain the electrode.

[0034] Comparative Example 2

[0035] A 10 cm * 10 cm titanium mesh substrate was placed in a 0.05 M oxalic acid solution and then immersed in the oxalic acid solution at 70 °C for 50 min before being removed. After washing repeatedly with ethanol and ultrapure water, it was dried in a 60 °C oven. Iron salt was mixed with ultrapure water and stirred until completely dissolved, then heated to 60 °C to prepare a 0.5 M iron solution, which was used as a hydrothermal solution. The hydrothermal solution and the treated titanium mesh were placed in a reactor for hydrothermal reaction at 150 °C for 9 h. After cooling to room temperature, the substrate was removed, rinsed, and dried to obtain the Fe / Ti electrode.

[0036] Comparative Example 3

[0037] A 10 cm * 10 cm titanium mesh substrate was placed in a 0.05 M oxalic acid solution and immersed in the oxalic acid solution at 70 °C for 50 min before being removed. After washing multiple times with ethanol and ultrapure water, it was dried in a 60 °C oven. Aluminum salt was mixed with ultrapure water and stirred until completely dissolved, then heated to 60 °C to prepare a 0.5 M aluminum solution, which was used as a hydrothermal solution. The hydrothermal solution and the treated titanium mesh were placed in a reactor for hydrothermal reaction at 150 °C for 9 h. After cooling to room temperature, the substrate was removed, rinsed, and dried to obtain the Al / Ti electrode.

[0038] Comparative Example 4

[0039] A method for preparing an electrode, comprising:

[0040] 1) Substrate pretreatment (Ti): Place a 10 cm * 10 cm titanium mesh substrate into a 0.05 M oxalic acid solution. After immersing the titanium mesh substrate in the oxalic acid solution at 70 °C for 50 min, remove it. After washing it multiple times with ethanol and ultrapure water, dry it in a 60 °C oven for later use.

[0041] 2) Hydrothermal preparation (Fe-Al / Ti): Iron salts and aluminum salts are mixed with ultrapure water and stirred until completely dissolved. The mixture is then heated to 60°C to prepare a mixed iron-aluminum solution containing 0.5M and 0.5M iron salts, which serves as the hydrothermal solution. The hydrothermal solution and the treated titanium mesh are placed in a reactor for hydrothermal reaction at 150°C for 9 hours. After cooling to room temperature, the mesh is removed, rinsed, and dried for later use to obtain the Fe-Al / Ti electrode.

[0042] 3) CV doping (Ni / Fe-Al / Ti): Soluble nickel salt is mixed with ultrapure water and stirred until completely dissolved, and then heated to 60°C to prepare a solution containing 0.1M nickel, which is used as the deposition solution; the Fe-Al / Ti electrode is placed in the deposition solution and electrochemical deposition is performed by cyclic voltammetry to dope nickel metal on the Fe-Al / Ti electrode deposition layer to obtain the electrode.

[0043] Comparative Example 5

[0044] A method for preparing an electrode, comprising:

[0045] 1) Substrate pretreatment (Ti): Place a 10 cm * 10 cm titanium mesh substrate into a 0.05 M oxalic acid solution. After immersing the titanium mesh substrate in the oxalic acid solution at 70 °C for 50 min, remove it. After washing it multiple times with ethanol and ultrapure water, dry it in a 60 °C oven for later use.

[0046] 2) Hydrothermal preparation (Fe-Al / Ti): Iron salts and aluminum salts are mixed with ultrapure water and stirred until completely dissolved. The mixture is then heated to 60°C to prepare a mixed iron-aluminum solution containing 0.5M and 0.5M iron salts, which serves as the hydrothermal solution. The hydrothermal solution and the treated titanium mesh are placed in a reactor for hydrothermal reaction at 150°C for 9 hours. After cooling to room temperature, the mesh is removed, rinsed, and dried for later use to obtain the Fe-Al / Ti electrode.

[0047] 3) CV doping (Zn / Fe-Al / Ti): Soluble zinc salt is mixed with ultrapure water and stirred until completely dissolved, and then heated to 60°C to prepare a solution containing 0.1M zinc, which is used as the deposition solution; the Fe-Al / Ti electrode is placed in the deposition solution and electrochemical deposition is performed by cyclic voltammetry to dope zinc metal on the Fe-Al / Ti electrode deposition layer to prepare the electrode.

[0048] Figure 1 The image shows a SEM image of the cathode electrode prepared in Example 1. The surface of the composite cathode electrode exhibits a loose and porous micron-sized particle aggregation morphology. The three-dimensional stacking forms abundant channels and a high specific surface area, providing sufficient active sites and an efficient mass transfer interface for the removal of calcium and magnesium ions.

[0049] The test results are shown in Table 1 below, which corresponds to the ion removal results.

[0050] Table 1

[0051]

[0052] Table 1 shows the data on calcium ion, magnesium ion, and total hardness removal rates of the synthesized electrode and its comparative examples.

[0053] A comparison of the removal rates of Example 1 and its comparative example clearly shows that, under the same experimental conditions, the removal rates of calcium ions, magnesium ions, and total hardness in Comparative Example 1 were 56.37%, 36.67%, and 38.54%, respectively, all superior to the comparative example. This demonstrates that Example 1 exhibits excellent electrochemical activity and good removal performance in electrochemical water treatment. The titanium-based metal electrode, prepared through a multi-step process of substrate cleaning and etching, hydrothermal loading, and electrochemical doping, effectively enhances the local pH of the cathode, promotes rapid precipitation of Mg(OH)2, inhibits dense adhesion of calcium and magnesium scale, and extends the electrode's self-cleaning cycle. Iron-aluminum metal coupling provides sufficient active sites for calcium and magnesium ion removal, while nickel and zinc doping can regulate the electronic states on the electrode surface and optimize interfacial electron transport, significantly improving electrodeposition efficiency and reaction selectivity. Ultimately, it exhibits excellent catalytic activity and structural stability in industrial water treatment.

[0054] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A method for preparing a titanium-based catalytic electrode, characterized in that the steps include... include: S1. Substrate pretreatment: First, the titanium substrate is placed in a heated pickling solution. The pickling solution cleans, etches, and activates the surface of the titanium substrate, effectively removing surface oil and natural oxide layers to increase surface roughness and specific surface area. S2. Hydrothermal preparation: Soluble iron salts and aluminum salts are mixed with ultrapure water and stirred until completely dissolved. The mixture is then heated to 40-80℃ to prepare a mixed iron-aluminum solution. The concentration of iron salts in the mixed iron-aluminum solution is 0.2-1M, and the concentration of aluminum salts is 0.2-1M. This mixed iron-aluminum solution is used as the hydrothermal solution. The hydrothermal solution and the pretreated titanium substrate are placed in a reactor for hydrothermal reaction at a temperature of 120℃-180℃ for 6-12 hours. After cooling to room temperature, the substrate is removed, rinsed, and dried for later use to obtain the Fe-Al / Ti electrode. S3, CV doping: Soluble nickel salt and zinc salt are mixed with ultrapure water and stirred until completely dissolved, then heated to 40-80℃ to prepare a mixed nickel-zinc solution. The concentration of nickel salt in the mixed nickel-zinc solution is 0.05-0.5M, and the concentration of zinc salt is 0.05-0.5M. The mixed nickel-zinc solution is used as the deposition solution. The Fe-Al / Ti electrode is placed in the deposition solution, and electrochemical deposition is performed using cyclic voltammetry. Nickel and zinc metals are doped on the Fe-Al / Ti electrode deposition layer to further improve the catalytic activity and stability of the electrode. Zinc element plays a role in regulating the electrode surface as an auxiliary metal, thereby obtaining a titanium-based catalytic electrode.

2. The method for preparing a titanium-based catalytic electrode according to claim 1, characterized in that, The titanium substrate is a titanium mesh.

3. The method for preparing a titanium-based catalytic electrode according to claim 1, characterized in that, In step S1, the pickling solution includes citric acid, ascorbic acid, or acetic acid.

4. The method for preparing a titanium-based catalytic electrode according to claim 1, characterized in that, In step S1, a 10 cm * 10 cm titanium mesh substrate is placed in a 0.01-0.1 M oxalic acid solution. The titanium substrate is then placed in the oxalic acid solution at 60℃-80℃ for 50 minutes and then removed. After washing it several times with ethanol and ultrapure water, it is placed in a 60℃ oven to dry for later use.

5. The method for preparing a titanium-based catalytic electrode according to claim 1, characterized in that, In step S2, the soluble iron salt includes one of ferric chloride, ferric nitrate, ferric sulfate, ferrous sulfate, and ferrous chloride; wherein the concentration of the iron salt in the hydrothermal solution is 0.5M.

6. The method for preparing a titanium-based catalytic electrode according to claim 1, characterized in that, In step S2, the soluble aluminum salt includes one of aluminum nitrate, alum, aluminum sulfate, and aluminum chloride; wherein the concentration of the aluminum salt in the hydrothermal solution is 0.5M.

7. The method for preparing a titanium-based catalytic electrode according to claim 1, characterized in that, In step S3, the soluble nickel salt includes one of nickel chloride, nickel nitrate, and nickel sulfate; wherein the concentration of the nickel salt in the precipitate is 0.1M.

8. The method for preparing a titanium-based catalytic electrode according to claim 1, characterized in that, In step S3, the soluble zinc salt includes one of zinc chloride, zinc nitrate, and zinc sulfate; wherein the concentration of the zinc salt in the precipitate is 0.1M.

9. The method for preparing a titanium-based catalytic electrode according to claim 1, characterized in that, In step S3, during electrochemical deposition, the activation voltage range is set to -0.6V to 1.8V, the scan rate is 3mV / s, and the number of scans is 8.

10. A water treatment cathode electrode, characterized in that, The titanium-based catalytic electrode is prepared by any of the methods described in claims 1-8 to remove calcium and magnesium ions from industrial water and reduce the total hardness of industrial water.

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