Precious metal-doped ferroferric oxide coating electrode and preparation method thereof

Abstract

This invention relates to the field of novel electrochemical electrode materials, providing a noble metal-doped Fe3O4 coated electrode and its preparation method. The method includes: S1, coating a conductive substrate with a Fe3O4 coating, wherein noble metal elements are uniformly distributed within or on the surface of the Fe3O4 coating; S2, subjecting the Fe3O4 coating doped with noble metals after step S1 to appropriate heat treatment, thereby obtaining the electrode. The electrode of this invention achieves high dispersion of noble metals on a carrier, and the resulting novel composite Fe3O4 coated electrode exhibits high electrocatalytic activity. Noble metals are loaded onto the conductive coating substrate in the form of single atoms or small clusters, optimizing cost and performance and improving the application efficiency of noble metal materials. The preparation process is simple, low-cost, and environmentally friendly. The prepared electrode has high noble metal utilization and excellent conductivity, while also possessing high reliability, resistance to poisoning, corrosion resistance, and long lifespan.

Description

Technical Field

[0001] This invention relates to the field of new electrochemical electrode materials, and in particular to a magnetite-coated electrode doped with noble metals and its preparation method. Background Technology

[0002] In electrochemical manufacturing practices, electrode materials are often crucial for improving process efficiency, reducing costs, and achieving environmentally friendly production.

[0003] Dimensionally stable electrodes (DSEs) are of great significance in applied electrochemistry. Traditional DSEs typically consist of a titanium substrate coated with a noble metal oxide coating (such as RuO2 and IrO2). These noble metal oxide coatings can significantly improve the efficiency of electrolysis reactions in industries including hydrogen electrolysis and chlor-alkali production, and possess excellent corrosion resistance, maintaining stability and long service life in highly corrosive environments.

[0004] However, the widespread application of noble metal electrode materials in electrolysis processes is significantly limited. First, the scarcity and high price of noble metal resources result in high investment costs for these electrode materials, limiting their economic feasibility for large-scale industrial applications. Second, the low utilization rate of active sites in traditional noble metal-based electrocatalysts leads to a cost-benefit mismatch, increasing operating costs. Furthermore, although noble metal electrode materials exhibit good corrosion resistance and chemical stability, their catalytic performance may gradually decline over long-term use, and this lack of long-term stability also contributes to increased costs.

[0005] Therefore, high utilization rate of precious metals and low cost of precious metal-based coated electrodes have always been one of the hot topics in the field of electrode technology. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a Fe3O4 coated electrode doped with precious metals and its preparation method. The Fe3O4 coated electrode with specific loading of precious metal elements has the advantages of excellent electrocatalytic performance, long life, low cost, environmental friendliness and high utilization rate of precious metals.

[0007] The present invention adopts the following technical solution:

[0008] On the one hand, the present invention provides a method for preparing a Fe3O4 coated electrode doped with noble metals. The method involves uniformly distributing noble metal elements onto the surface layer of a high-temperature and oxidation-resistant conductive substrate carrier, and then heat-treating the substrate to load the noble metals onto the Fe3O4 coating, thereby obtaining a Fe3O4 coated electrode doped with noble metals.

[0009] Specifically, a method for preparing a magnetite-coated electrode doped with noble metals includes:

[0010] S1. The conductive substrate is coated with Fe3O4 coating, and the noble metal elements are uniformly distributed in the Fe3O4 coating or on the surface of the Fe3O4 coating.

[0011] S2. The Fe3O4 coating doped with noble metal after step S1 is subjected to heat treatment to obtain the Fe3O4 coating electrode doped with noble metal.

[0012] In addition to any of the possible implementations described above, another implementation is provided in which, in step S1, the noble metal element is uniformly distributed within the Fe3O4 coating. The specific method includes:

[0013] S11. Slurry preparation: Mix the precious metal soluble salt, Fe3O4 powder, organic binder and dispersing solvent to prepare a uniform slurry;

[0014] S12. Coating: The prepared slurry is coated onto the surface of a conductive substrate material or an electrode material coated with Fe3O4 to form a Fe3O4 material coating layer doped with noble metals.

[0015] In addition to any of the possible implementations described above, another implementation is provided in which, in step S1, the noble metal element is uniformly distributed on the surface layer of the Fe3O4 coating. Specifically, the method is to coat the surface of the prepared Fe3O4 coating with a noble metal soluble salt solution.

[0016] In addition to any of the possible implementations described above, a further implementation is provided, in which the Fe3O4 coating is prepared by a high-temperature spraying method, specifically: Fe3O4 powder is fed into a spray gun, the Fe3O4 powder is heated by high temperature, and the Fe3O4 powder is sprayed onto the surface of a conductive substrate by a high-speed airflow to form a uniform Fe3O4 coating.

[0017] In addition to any of the possible implementations described above, another implementation is provided in which, in step S11, the precious metal element is one or more combinations of iridium, platinum, palladium, ruthenium, rhodium, and rhenium.

[0018] The conductive substrate is made of high-temperature and oxidation-resistant materials, including metallic materials such as stainless steel, inorganic non-metallic materials such as silicon carbide, and metallic materials covered with conductive ceramic coatings.

[0019] The organic adhesive is one of polyvinyl alcohol, methyl polyvinyl acetate, and methylcellulose;

[0020] The dispersing solvent is one of ethanol, water, and ethylene glycol.

[0021] In addition to any of the possible implementations described above, another implementation is provided in which the conductive substrate material in step S11 is in the form of a sheet, mesh, block, rod, or strip.

[0022] In addition to any of the possible implementations described above, another implementation is provided in which the heat treatment in step S2 includes sintering heat treatment and thermal diffusion heat treatment.

[0023] In addition to any of the possible implementations described above, another implementation is provided, in step S2,

[0024] When the noble metal elements are uniformly distributed within the Fe3O4 coating, the slurry is coated onto the conductive substrate surface and then subjected to sintering heat treatment. The specific process is as follows:

[0025] S21. Place the conductive substrate coated with Fe3O4 of precious metal into a high-temperature heating furnace and introduce a protective atmosphere.

[0026] S22. Raise the temperature of the high-temperature heating furnace to 250-300℃ at a rate of 2-4℃ / min, and hold at this temperature for 5-20 minutes to perform glue removal.

[0027] S23. Continue to raise the temperature to 1050-1200℃ at a rate of 200-400℃ / h, and hold at this temperature for 3-10 minutes for sintering treatment;

[0028] S24. The conductive substrate coated with the Fe3O4 coating of noble metal is naturally cooled to room temperature by the furnace body to obtain the Fe3O4 coated electrode doped with noble metal.

[0029] In addition to any of the possible implementations described above, another implementation is provided in which the high-temperature heating furnace is a tube furnace or an electric resistance furnace.

[0030] In addition to any of the possible implementations described above, another implementation is provided in which the protective atmosphere is nitrogen or argon.

[0031] In addition to any of the possible implementations described above, another implementation is provided, in step S2,

[0032] When the noble metal element is uniformly distributed on the surface layer of the Fe3O4 coating, a noble metal soluble salt solution is coated onto the prepared Fe3O4 coating surface, followed by thermal diffusion heat treatment, specifically including:

[0033] X21. Place the Fe3O4 coating, which has been coated with a precious metal soluble salt solution, into a high-temperature heating furnace and introduce a protective atmosphere.

[0034] X22. Raise the temperature of the high-temperature heating furnace to 500-600℃ at a rate of 2-4℃ / min, and hold at this temperature for 5-20min;

[0035] X23. Subsequently, the Fe3O4 coating coated with a noble metal soluble salt solution was allowed to cool naturally to room temperature in the furnace, resulting in a Fe3O4 coated electrode doped with noble metal.

[0036] In addition to any of the possible implementations described above, another implementation is provided in which the coating in step S12 is one of the following methods: drop coating, immersion coating, and spray coating.

[0037] On the other hand, the present invention also provides a magnetite coated electrode doped with noble metals, wherein the magnetite coated electrode doped with noble metals is prepared by the above method.

[0038] The reason for choosing a Fe3O4 coating doped with noble metals in this invention is as follows:

[0039] 1. The different valence states of iron ions at the octahedral positions in Fe3O4 accelerate electron transitions, resulting in significantly high conductivity. This promotes electron transfer between the catalyst and electrode, enhancing the efficiency of electrocatalytic reactions. Furthermore, the high specific surface area and abundant defect sites of the Fe3O4 coating mean it can provide more surface area for loading noble metal particles, thereby increasing its electrocatalytic activity. Noble metals themselves possess excellent electrocatalytic performance. Therefore, uniformly dispersing noble metals in the Fe3O4 coating can further enhance the conductivity of the coating electrode and significantly increase the active sites for electrocatalytic reactions, thus improving overall electrocatalytic performance.

[0040] 2. Fe3O4 also has high stability due to its unique anti-spinel structure, which is conducive to providing a long service life.

[0041] 3. Fe3O4 itself is an environmentally friendly material. The preparation process is relatively simple and has little impact on the environment. Precious metal resources are scarce and expensive. By dispersing precious metals in the Fe3O4 coating, the amount of precious metals used can be significantly reduced, thereby reducing costs and resource consumption.

[0042] The beneficial effects of this invention are as follows:

[0043] The noble metal-doped coated electrode provided by this invention achieves high dispersion of noble metals on a carrier, allowing the noble metals to be loaded onto the conductive coating substrate in the form of single atoms or small clusters. This optimizes cost and performance, improving the application efficiency of noble metal materials. The preparation process is simple, low-cost, and environmentally friendly. The prepared noble metal-doped Fe3O4 coated electrode exhibits high noble metal utilization and excellent conductivity, while also possessing high reliability, resistance to poisoning, corrosion resistance, and long lifespan. Attached Figure Description

[0044] Figure 1 The diagram shown is a schematic flowchart of a method for preparing a magnetite-coated electrode doped with noble metals according to an embodiment of the present invention.

[0045] Figure 2 The diagram shown is a schematic diagram of the flat conductive substrate structure in the embodiment.

[0046] Figure 3 The diagram shown is a schematic of the flat conductive substrate material after being coated with a Fe3O4 coating doped with noble metals in the embodiment. Detailed Implementation

[0047] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that the technical features or combinations of technical features described in the following embodiments should not be considered in isolation, but can be combined with each other to achieve better technical effects.

[0048] like Figure 1 As shown, an embodiment of the present invention provides a method for preparing a magnetite-coated electrode doped with noble metals, comprising:

[0049] S1. The conductive substrate is coated with Fe3O4 coating, and the noble metal elements are uniformly distributed in the Fe3O4 coating or on the surface of the Fe3O4 coating.

[0050] S2. The Fe3O4 coating doped with noble metal after step S1 is subjected to heat treatment to obtain the Fe3O4 coating electrode doped with noble metal.

[0051] In one specific embodiment, in step S1, the noble metal element is uniformly distributed within the Fe3O4 coating, and the specific method includes:

[0052] S11. Slurry preparation: Mix the precious metal soluble salt, Fe3O4 powder, organic binder and dispersing solvent to prepare a uniform slurry;

[0053] S12. Coating: The prepared slurry is coated onto the surface of a conductive substrate material or an electrode material coated with Fe3O4 to form a Fe3O4 material coating layer doped with noble metals.

[0054] In one specific embodiment, in step S1, the noble metal element is uniformly distributed on the surface layer of the Fe3O4 coating. The specific method is to coat the surface of the prepared Fe3O4 coating with a noble metal soluble salt solution.

[0055] In one specific embodiment, the Fe3O4 coating is prepared by a high-temperature spraying method, which involves feeding Fe3O4 powder into a spray gun, heating the Fe3O4 powder at high temperature, and spraying the Fe3O4 powder onto the surface of a conductive substrate by a high-speed airflow to form a uniform Fe3O4 coating.

[0056] In one specific embodiment, in step S11, the precious metal element is one or more combinations of iridium, platinum, palladium, ruthenium, rhodium, and rhenium;

[0057] The conductive substrate is made of high-temperature and oxidation-resistant materials, including metallic materials such as stainless steel, inorganic non-metallic materials such as silicon carbide, and metallic materials covered with conductive ceramic coatings.

[0058] The organic adhesive is one of polyvinyl alcohol, methyl polyvinyl acetate, and methylcellulose;

[0059] The dispersing solvent is one of ethanol, water, and ethylene glycol.

[0060] The choice of organic adhesives can be based on specific needs. For example, polyvinyl alcohol (PVA) has good solubility in water, making it easy to adjust the concentration and viscosity of the adhesive to meet the needs of different applications. It is an environmentally friendly material, harmless and non-toxic, and has good chemical resistance, resisting the erosion of oils, solvents, etc. Compared with PVA, methyl polyvinyl acetate (MCA) has better water resistance; the dried film is not easily hydrolyzed, making it suitable for applications requiring a certain degree of waterproofing. It can be mixed with a variety of other materials, providing good compatibility and a wide range of applications. Methylcellulose is temperature sensitive; its solubility changes with temperature, making it suitable for specific temperature-controlled applications. It has good tolerance to salts and is stable over a wide pH range.

[0061] Dispersants such as ethanol have good volatility and can evaporate rapidly at room temperature, making them suitable for applications requiring rapid drying. They can dissolve a variety of organic substances and some inorganic salts, are compatible with many other solvents, and can be used to formulate multi-component solvent systems. Water is one of the most environmentally friendly and safest solvents, producing no harmful volatiles, making it friendly to operators and the environment. It is also one of the most readily available and lowest-cost solvents, suitable for large-scale industrial production. Ethylene glycol has low volatility, making it suitable for applications requiring the solvent to remain in the system for extended periods. It has a high boiling point, allowing it to be used as a solvent at higher temperatures, making it suitable for reactions under high-temperature conditions. It does not easily freeze at low temperatures and is commonly used as an antifreeze. Therefore, it is used as a solvent in chemical processes requiring low-temperature conditions. It can dissolve a variety of organic substances and some inorganic substances, exhibiting good solubility, especially for certain poorly soluble substances.

[0062] In one specific embodiment, in step S11, the conductive substrate material is in the form of sheets, meshes, blocks, rods, or wires.

[0063] In one specific embodiment, step S2 includes sintering heat treatment and thermal diffusion heat treatment.

[0064] In one specific embodiment, in step S2,

[0065] When the noble metal elements are uniformly distributed within the Fe3O4 coating, the slurry is coated onto the conductive substrate surface and then subjected to sintering heat treatment. The specific process is as follows:

[0066] S21. Place the conductive substrate coated with Fe3O4 of precious metal into a high-temperature heating furnace and introduce a protective atmosphere.

[0067] S22. Raise the temperature of the high-temperature heating furnace to 250-300℃ at a rate of 2-4℃ / min, and hold at this temperature for 5-20 minutes to perform glue removal.

[0068] S23. Continue to raise the temperature to 1050-1200℃ at a rate of 200-400℃ / h, and hold at this temperature for 3-10 minutes for sintering treatment;

[0069] S24. The conductive substrate coated with the Fe3O4 coating of noble metal is naturally cooled to room temperature by the furnace body to obtain the Fe3O4 coated electrode doped with noble metal.

[0070] In one specific embodiment, the high-temperature heating furnace is a tubular furnace or an electric resistance furnace.

[0071] In one specific embodiment, the protective atmosphere is nitrogen or argon.

[0072] In addition to any of the possible implementations described above, another implementation is provided, in step S2,

[0073] When the noble metal element is uniformly distributed on the surface layer of the Fe3O4 coating, a noble metal soluble salt solution is coated onto the prepared Fe3O4 coating surface, followed by thermal diffusion heat treatment, specifically including:

[0074] X21. Place the Fe3O4 coating, which has been coated with a precious metal soluble salt solution, into a high-temperature heating furnace and introduce a protective atmosphere.

[0075] X22. Raise the temperature of the high-temperature heating furnace to 500-600℃ at a rate of 2-4℃ / min, and hold at this temperature for 5-20min;

[0076] X23. Subsequently, the Fe3O4 coating coated with a noble metal soluble salt solution was allowed to cool naturally to room temperature in the furnace, resulting in a Fe3O4 coated electrode doped with noble metal.

[0077] In one specific embodiment, in step S12, the coating is one of the following methods: drop coating, immersion coating, and spray coating.

[0078] This invention provides a noble metal-doped magnetite coated electrode, which is prepared by the above method.

[0079] Example 1

[0080] Using 2μm Fe3O4 powder, PVA (polyvinyl alcohol), ethanol, and a 405 stainless steel plate with dimensions of 20cm × 10cm × 1mm, such as... Figure 2 As shown, a novel coated electrode was prepared by mixing Fe3O4 powder with PVA and finely grinding it to obtain a uniform PVA-Fe3O4 fine powder. Then, the fine powder was mixed with ethanol to form a slurry. The slurry was uniformly coated onto a 405 stainless steel conductive substrate to form a coating. Finally, the stainless steel plate coated with the Fe3O4 slurry was placed in a tube furnace and sintered under nitrogen protection. After cooling, the Fe3O4 coated electrode with stainless steel as the conductive substrate was obtained. The process parameters are as follows:

[0081] Heating: Starting from room temperature, increase the temperature to 250°C at a rate of 2°C / min;

[0082] Debinding treatment: Keep warm at 250℃ for 20 minutes;

[0083] Continue heating: Increase the temperature from 250℃ to 1100℃ at a rate of 200℃ / h;

[0084] Sintering treatment: Hold at 1100℃ for 5 minutes;

[0085] Cooling: Cool to room temperature with the furnace.

[0086] A chloroiridic acid solution was drop-coated onto the Fe3O4 coating surface at a coating depth of 1 mg / cm². 2 Subsequently, the coating material was placed in a tube furnace and subjected to thermal diffusion treatment in a nitrogen protective atmosphere to obtain an Fe3O4 coated electrode doped with the noble metal iridium. Figure 3 As shown, the process parameters are as follows:

[0087] Heating: Starting from room temperature, increase the temperature to 600℃ at a rate of 2℃ / min;

[0088] Heat diffusion treatment: Hold at 600℃ for 10 minutes;

[0089] Cooling: Cool to room temperature along with the furnace.

[0090] Example 2

[0091] The Fe3O4 slurry prepared in Example 1 was uniformly mixed with a 0.5 g / L platinum hexachloroplatinic acid ethanol solution. The mixed slurry was then drop-coated onto the surface of a 316L stainless steel plate to form a coating layer. Subsequently, this coating material was placed in a resistance furnace and sintered under a nitrogen protective atmosphere to load the noble metal platinum onto the Fe3O4 coating, resulting in a platinum-doped Fe3O4 coated electrode. The process parameters are as follows:

[0092] Heating: Starting from room temperature, increase the temperature to 300°C at a rate of 3°C / min;

[0093] Debinding process: Keep warm at 300℃ for 5 minutes;

[0094] Continue heating: Increase the temperature from 300℃ to 1200℃ at a rate of 300℃ / h;

[0095] Sintering treatment: Hold at 1200℃ for 3 minutes;

[0096] Cooling: Cool to room temperature along with the furnace.

[0097] Example 3

[0098] Preparation of Fe3O4 Coating: A novel coated electrode was prepared using 20μm Fe3O4 powder, plasma spraying equipment, and a 316L stainless steel plate with dimensions of 20cm × 10cm × 1mm. The specific steps involved feeding the Fe3O4 powder into a spray gun, activating the plasma spraying equipment, heating the Fe3O4 powder with a high-temperature plasma arc, and then spraying it onto a 316L stainless steel conductive substrate using a high-speed nitrogen gas stream to form a coating. The sprayed coating was then allowed to cool naturally, resulting in an Fe3O4 coating with stainless steel as the conductive substrate. Figure 1 As shown, the process parameters are as follows:

[0099] Feed rate: 10g / min;

[0100] Spraying rate: 3m / s;

[0101] Spray gun movement speed: 20cm / min;

[0102] Spraying distance: 100mm;

[0103] Carrier gas flow rate: 30L / min;

[0104] Auxiliary gas flow rate: 10L / min.

[0105] Using the prepared Fe3O4 coating as a carrier, a mixed noble metal salt solution was obtained by mixing hexachloroplatinic acid ethanol solution and chloropalladiumic acid ethanol solution. The prepared Fe3O4 slurry was then mixed with the mixed noble metal salt solution to obtain a mixed slurry. The surface of the Fe3O4 coating was immersed in the mixed slurry, ensuring complete coverage of the coating. The slurry coating amount was 0.5 mg / cm². 2 After immersion for 5 minutes, the sample was removed. The coating material was then placed in a tube furnace and sintered under an argon protective atmosphere to obtain an Fe3O4 coated electrode doped with the noble metals platinum and palladium. The process parameters are as follows:

[0106] Heating: Starting from room temperature, increase the temperature to 260°C at a rate of 4°C / min;

[0107] De-adhesion treatment: Keep warm at 260℃ for 10 minutes;

[0108] Continue heating: Increase the temperature from 260℃ to 1050℃ at a rate of 400℃ / h;

[0109] Sintering treatment: Hold at 1050℃ for 10 minutes;

[0110] Cooling: Cool to room temperature along with the furnace.

[0111] Example 4

[0112] The Fe3O4 coating prepared in Example 3 was used as a carrier. The surface of the Fe3O4 coating was completely immersed in a ruthenium trichloride ethylene glycol solution with a ruthenium concentration of 0.5 mg / ml. After 5 minutes, the sample was removed and then placed in a resistance furnace for thermal diffusion treatment under an argon protective atmosphere to obtain an Fe3O4 coated electrode doped with the noble metal ruthenium. The process parameters are as follows:

[0113] Heating: Starting from room temperature, increase the temperature to 500°C at a rate of 3°C / min;

[0114] Thermal diffusion treatment: Hold at 500℃ for 20 minutes;

[0115] Cooling: Cool to room temperature along with the furnace.

[0116] The electrode of this invention possesses advantages such as excellent electrocatalytic performance, long lifespan, low cost, environmental friendliness, and high utilization rate of precious metals. The electrode of this invention exhibits superior electrocatalytic performance in electrocatalytic tests, characterized by low overpotential, small Tafel slope, and low charge transfer resistance, and demonstrates stable catalytic effects during long-term, high-current electrochemical testing. Through practical comparative analysis, the electrode of this invention shows significantly improved electrocatalytic performance and lifespan compared to traditional iron-based catalysts.

[0117] While several embodiments of the present invention have been provided herein, those skilled in the art should understand that modifications can be made to these embodiments without departing from the spirit of the invention. The above embodiments are merely exemplary and should not be construed as limiting the scope of the invention.

Claims

1. A method for preparing a magnetite-coated electrode doped with noble metals, characterized in that, The method includes: S1. The conductive substrate is coated with Fe3O4 coating, and the noble metal elements are uniformly distributed in the Fe3O4 coating or on the surface of the Fe3O4 coating. S2. Heat-treat the Fe3O4 coating doped with noble metal after step S1 to obtain the Fe3O4 coating electrode doped with noble metal. In step S1, the noble metal elements are uniformly distributed within the Fe3O4 coating. The specific method includes: S11. Slurry preparation: Mix the precious metal soluble salt, Fe3O4 powder, organic binder and dispersing solvent to prepare a uniform slurry; S12. Coating: The prepared slurry is coated onto the surface of a conductive substrate material or an electrode material coated with Fe3O4 to form a Fe3O4 material coating layer doped with noble metals. In step S2, the heat treatment includes sintering heat treatment and thermal diffusion heat treatment; When the noble metal elements are uniformly distributed within the Fe3O4 coating, the slurry is coated onto the surface of the conductive substrate, followed by sintering heat treatment. The specific process is as follows: S21. Place the conductive substrate coated with Fe3O4 of precious metal into a high-temperature heating furnace and introduce a protective atmosphere. S22. Raise the temperature of the high-temperature heating furnace to 250-300℃ at a rate of 2-4℃ / min, and hold at this temperature for 5-20 minutes to perform glue removal. S23. Continue to raise the temperature to 1050-1200℃ at a rate of 200-400℃ / h, and hold at this temperature for 3-10 minutes for sintering treatment; S24. The conductive substrate coated with the Fe3O4 coating of noble metal is naturally cooled to room temperature by the furnace body to obtain the Fe3O4 coated electrode doped with noble metal. When the noble metal element is uniformly distributed on the surface layer of the Fe3O4 coating, a noble metal soluble salt solution is coated onto the prepared Fe3O4 coating surface, followed by thermal diffusion heat treatment, specifically including: X21. Place the Fe3O4 coating, which has been coated with a precious metal soluble salt solution, into a high-temperature heating furnace and introduce a protective atmosphere. X22. Raise the temperature of the high-temperature heating furnace to 500-600℃ at a rate of 2-4℃ / min, and hold at this temperature for 5-20min; X23. Subsequently, the Fe3O4 coating coated with a noble metal soluble salt solution was allowed to cool naturally to room temperature in the furnace, resulting in a Fe3O4 coated electrode doped with noble metal.

2. The method for preparing a magnetite-coated electrode doped with noble metals as described in claim 1, characterized in that, In step S1, the noble metal elements are uniformly distributed on the surface layer of the Fe3O4 coating. Specifically, the method is to coat the surface of the prepared Fe3O4 coating with a noble metal soluble salt solution.

3. The method for preparing a magnetite-coated electrode doped with noble metals as described in claim 2, characterized in that, The Fe3O4 coating was prepared by high-temperature spraying, specifically by feeding Fe3O4 powder into a spray gun, heating the Fe3O4 powder at high temperature, and spraying the Fe3O4 powder onto the surface of a conductive substrate by a high-speed airflow to form a uniform Fe3O4 coating.

4. The method for preparing a magnetite-coated electrode doped with noble metals as described in claim 1, characterized in that, In step S11, the precious metal element is one or more combinations of iridium, platinum, palladium, ruthenium, rhodium, and rhenium; The conductive substrate is made of high-temperature and oxidation-resistant materials, including metallic materials, inorganic non-metallic materials, and metallic materials coated with conductive ceramic coatings. The organic adhesive is one of polyvinyl alcohol, methyl polyvinyl acetate, and methylcellulose; The dispersing solvent is one of ethanol, water, and ethylene glycol; The conductive substrate material is in the form of sheets, meshes, blocks, rods, or wires.

5. The method for preparing a magnetite-coated electrode doped with noble metals as described in claim 1, characterized in that, In step S12, the coating is performed using one of the following methods: drop coating, immersion coating, or spray coating.

6. A magnetite-coated electrode doped with noble metals, characterized in that, The magnetite-coated electrode doped with noble metals is prepared by the method described in any one of claims 1-5.

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