Amorphous ruthenium / manganese-doped tungsten oxide hydrogen evolution electrode resistant to calcium and magnesium deposition, and preparation method and seawater electrolysis application thereof

Abstract

The application belongs to the technical field of energy and electrochemical catalysis, and discloses an amorphous ruthenium / manganese-doped tungsten oxide hydrogen evolution electrode resistant to calcium and magnesium deposition and a preparation method and seawater electrolysis application thereof. The electrode comprises an electrically conductive substrate and a manganese-doped tungsten oxide nanoarray loaded thereon, and is anchored with amorphous ruthenium on the surface. The preparation is obtained by growing the nanoarray through a hydrothermal method, immersing in ruthenium chloride and then performing plasma treatment. The manganese doping effectively enhances the electrical conductivity of the material, and in combination with the rich active sites of the amorphous ruthenium, significantly reduces the hydrogen evolution overpotential; the synergistic effect of the two further constructs a local acidic microenvironment on the electrode surface, fundamentally inhibiting the nucleation and adhesion of calcium / magnesium hydroxide and other alkaline precipitates. The application has a simple process, effectively solves the problem of deactivation of traditional cathodes in seawater electrolysis due to fouling, exhibits excellent hydrogen evolution activity and long-term stability, and has a wide application prospect.

Description

Technical Field

[0001] This invention relates to an amorphous ruthenium / manganese-doped tungsten oxide hydrogen evolution electrode resistant to calcium and magnesium deposition, its preparation method and application, belonging to the field of energy and electrochemical catalysis technology. Background Technology

[0002] Seawater, as the most abundant water resource on Earth, accounting for 96.5% of global water resources, is considered an ideal way to solve the freshwater shortage problem through seawater electrolysis, possessing significant economic value and ecological advantages. However, seawater contains a large amount of calcium... 2+ Mg 2+ Cl - And various impurity ions, the hydrogen evolution process at the cathode continuously generates OH. - It is easy for insoluble magnesium hydroxide and calcium hydroxide precipitates to form on the electrode surface, which can block catalytic active sites and block charge transport channels, thus imposing stringent requirements on the anti-scaling ability, corrosion resistance, and high-current stability of the catalytic electrode.

[0003] Traditional platinum-based noble metal catalysts exhibit excellent hydrogen evolution kinetics, but the scarcity of noble metal reserves and high procurement costs make them unsuitable for large-scale industrial hydrogen production. Tungsten oxide-based materials possess proton storage properties, which can buffer electrode interface alkalization to some extent, but the proton insertion / extraction kinetics of pure tungsten oxide are sluggish, leading to a rapid increase in local pH at the interface under high current conditions, and the problem of calcium and magnesium precipitation remains prominent. Single ruthenium-based catalysts have limited active sites and lack a proton buffering system, resulting in rapid surface coating with hydroxides after long-term seawater electrolysis, causing a rapid decline in catalytic performance. Existing doping modification and heterojunction control methods mostly only improve the inherent hydrogen evolution activity and cannot fundamentally solve the problem of calcium and magnesium precipitation passivation at the seawater cathode. Single-structure materials generally suffer from the shortcoming of being unable to simultaneously achieve both activity and long-term stability.

[0004] In recent years, the interfacial microenvironment regulation strategy has been proven to be an effective way to solve the problem of scaling on seawater electrodes. By constructing a localized acidification interface, it is possible to neutralize the OH- enriched at the cathode. - Thermodynamically, this method suppresses the nucleation and precipitation of hydroxides. Manganese possesses tunable multi-valence states; doping it with tungsten oxide can induce lattice distortion and generate a large number of oxygen vacancies, significantly enhancing the proton sponge capacity of tungsten oxide. Amorphous ruthenium has a large number of unsaturated coordination active sites, which can greatly accelerate the hydrogen evolution reaction kinetics. The synergy of these two elements can simultaneously achieve anti-precipitation and high catalytic activity. Therefore, developing a manganese-doped tungsten oxide-supported amorphous ruthenium three-dimensional nanorod array electrode, which utilizes a dynamic localized acidification microenvironment to achieve long-term repulsion of calcium and magnesium precipitation while maintaining excellent HER activity and seawater corrosion resistance, can overcome the industry pain points of traditional seawater electrodes, such as easy scaling, short lifespan, and high consumption of precious metals. This provides a new electrode solution for wind-solar coupled seawater hydrogen production, contributing to the sustainable development of the marine hydrogen energy industry. Summary of the Invention

[0005] This invention relates to an amorphous ruthenium / manganese-doped tungsten oxide hydrogen evolution electrode resistant to calcium and magnesium deposition, its preparation method, and its application in seawater electrolysis, aiming to achieve long-lasting anti-scaling, high-efficiency, and stable seawater electrolysis hydrogen evolution under industrial-grade high current density.

[0006] To achieve the above objectives, this invention provides an amorphous ruthenium / manganese-doped tungsten oxide hydrogen evolution electrode resistant to calcium and magnesium deposition. Amorphous ruthenium is loaded onto the surface of a manganese-doped tungsten oxide nanoarray to form a heterostructure. The electrode exhibits a nanoarray structure, and a strong metal-support interaction is formed between the amorphous ruthenium and the manganese-doped tungsten oxide support, inducing electron migration from ruthenium to the tungsten oxide support and optimizing the hydrogen evolution activity of the ruthenium sites. Oxygen vacancies introduced by manganese doping regulate the electronic structure and surface charge state of the tungsten oxide. The electrode surface exhibits a positive charge due to interfacial charge transfer between ruthenium and tungsten oxide, inhibiting the migration of calcium and magnesium ions from seawater to the cathode surface through electrostatic repulsion, thus preventing the deposition of hydroxide precipitates. Simultaneously, by constructing an acidified microenvironment in situ at the electrode / electrolyte interface, Mg2+ deposition is effectively inhibited. 2+ and Ca 2+ Hydroxide deposition on the cathode surface enables efficient and stable hydrogen production via seawater electrolysis.

[0007] This invention also provides a method for preparing an amorphous ruthenium / manganese-doped tungsten oxide hydrogen evolution electrode resistant to calcium and magnesium deposition, comprising the following steps:

[0008] Step 1: Cut the conductive substrate to the appropriate size, and clean it with hydrochloric acid, anhydrous ethanol and ultrapure water in sequence using ultrasonic cleaning. After cleaning, place it in an oven to dry for later use.

[0009] Step 2: Dissolve the tungsten source and manganese source in a solvent in a certain proportion and stir thoroughly to obtain a mixed solution. Place the pretreated conductive substrate in this solution and grow a manganese-doped tungsten oxide nanoarray in situ on the conductive substrate via a hydrothermal reaction.

[0010] Step 3: Immerse the manganese-doped tungsten oxide electrode obtained in Step 2 in a precursor solution containing ruthenium salt, and load ruthenium species on the surface of manganese-doped tungsten oxide by the immersion-adsorption method to obtain a ruthenium salt / manganese-doped tungsten oxide composite electrode.

[0011] Step 4: Place the product obtained in Step 3 in a plasma processing device and perform plasma irradiation treatment under a specific atmosphere to transform the loaded ruthenium species into amorphous ruthenium nanoparticles and strengthen the metal-support interaction between amorphous ruthenium and manganese-doped tungsten oxide support, thereby obtaining an amorphous ruthenium-loaded manganese-doped tungsten oxide heterojunction electrode.

[0012] Preferably, in step 1:

[0013] The conductive substrate is carbon paper, carbon cloth, or nickel foam. The cutting area is determined according to actual needs and requires pretreatment: ultrasonic cleaning with hydrochloric acid, ethanol, and ultrapure water for 15-25 minutes in sequence, followed by drying at 50-70℃.

[0014] Preferably, in step 2:

[0015] The tungsten source is any one of sodium tungstate, ammonium metatungstate, tungsten chloride, or sodium tungstate, and its concentration in the solution is 0.01-0.10 M;

[0016] The manganese source is any one of manganese nitrate, manganese chloride, manganese acetate, or manganese sulfate, and the final manganese doping level is controlled to be 2~8 at.% by adjusting the amount of manganese source added.

[0017] The hydrothermal reaction temperature is 160-200℃, and the hydrothermal reaction time is 12-20 h;

[0018] Preferably, in step 3:

[0019] The ruthenium salt precursor is an aqueous solution of ruthenium trichloride with a molar concentration of 0.001-0.02 M; the impregnation time is 5-20 min.

[0020] Preferably, in step 4:

[0021] The atmosphere for plasma treatment is any one of argon, nitrogen, or an argon-hydrogen mixture (H2 volume fraction 5%).

[0022] The plasma treatment pressure is 10-100 Pa;

[0023] The power of the plasma treatment is 50-300 W;

[0024] The plasma treatment time is 5-15 minutes;

[0025] Through plasma treatment, the loaded ruthenium species are reduced in situ and transformed into amorphous ruthenium nanoparticles. At the same time, the high-energy particle bombardment effect in the plasma generates a strong metal-support interaction at the interface between ruthenium and manganese-doped tungsten oxide.

[0026] In addition, this application also provides an application of the above-described amorphous ruthenium / manganese-doped tungsten oxide hydrogen evolution electrode, which is resistant to calcium and magnesium deposition, in seawater electrolysis for hydrogen production.

[0027] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0028] 1. This invention provides a method for preparing an amorphous ruthenium / manganese-doped tungsten oxide hydrogen evolution electrode resistant to calcium and magnesium deposition. The method employs a hydrothermal approach combined with impregnation-adsorption and plasma treatment processes to construct an amorphous ruthenium-supported manganese-doped tungsten oxide nanoarray heterojunction electrode in situ on a conductive substrate. The process is simple and controllable, with mild operating conditions, avoiding the damage to the nanostructure caused by prolonged high-temperature treatment, and is easy to scale up for mass production. Tungsten and manganese are abundant transition metal elements in the raw materials used, while the ruthenium loading is extremely low (only 1 / 10 to 1 / 5 of that of noble metal catalysts), significantly reducing the electrode preparation cost while ensuring high catalytic activity. Plasma treatment technology, as a green and efficient surface modification method, eliminates the need for chemical reducing agents, avoiding the problem of impurity residues in traditional liquid-phase reduction methods.

[0029] 2. In the amorphous ruthenium / manganese-doped tungsten oxide heterojunction electrode prepared in this invention, amorphous ruthenium provides abundant low-coordination active sites and a large number of dangling bonds, significantly improving the density of catalytic active centers. Manganese doping effectively modulates the band structure and oxygen vacancy concentration of tungsten oxide, enhancing the electronic conductivity of the support and its ability to regulate the adsorption / desorption of reaction intermediates. Plasma treatment not only achieves the amorphization of ruthenium species but also constructs a strong metal-support interaction at the interface between amorphous ruthenium and manganese-doped tungsten oxide, inducing electron migration from ruthenium to tungsten oxide and optimizing the hydrogen evolution reaction barrier at ruthenium sites. The synergistic effect of these three factors enables the electrode to exhibit excellent HER activity and durability in seawater.

[0030] 3. This invention utilizes an in-situ acidified microenvironment constructed at the amorphous ruthenium / manganese-doped tungsten oxide interface to maintain the local pH value of the cathode surface at 7.5–9.5 during seawater electrolysis, effectively suppressing Mg2+. 2+ and Ca 2+ Hydroxide precipitate is generated. Compared with existing technologies that use external electric fields, add deposition sites, or use ultrasonic cleaning, this invention starts from the interfacial chemical properties of the material itself, achieving an active, in-situ, and long-lasting anti-deposition effect without the need for additional equipment and additives, resulting in lower cost and simpler operation.

[0031] 4. The amorphous ruthenium / manganese-doped tungsten oxide hydrogen evolution electrode prepared by this invention can effectively inhibit calcium and magnesium deposition, avoiding the blockage and coverage of active sites by precipitates. At the same time, the amorphous ruthenium / manganese-doped tungsten oxide composite structure itself has good chemical stability and corrosion resistance, enabling the electrode to operate stably for a long time in seawater electrolysis. It has great practical application value and is especially suitable for large-scale industrial seawater electrolysis hydrogen production applications. Attached Figure Description

[0032] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below.

[0033] Figure 1 The XRD pattern of the amorphous ruthenium / manganese-doped tungsten oxide hydrogen evolution electrode prepared in Example 1 of this invention;

[0034] Figure 2 The image shows a scanning electron microscope (SEM) image of the amorphous ruthenium / manganese-doped tungsten oxide hydrogen evolution electrode prepared in Example 1 of this invention.

[0035] Figure 3 Transmission electron microscopy (TEM) images and selected area electron diffraction (SAED) patterns of the amorphous ruthenium / manganese-doped tungsten oxide hydrogen evolution electrode prepared in Example 1 of the present invention show that ruthenium exists in an amorphous state.

[0036] Figure 4 This is a comparison of the linear sweep voltammetry (LSV) curves of the hydrogen evolution electrode prepared in Example 1 of the present invention and the comparative electrode in simulated seawater electrolyte.

[0037] Figure 5 This is a comparison of the potential-time curves of the hydrogen evolution electrode prepared in Example 1 of the present invention and the comparative electrode during constant current electrolysis in simulated seawater electrolyte.

[0038] Figure 6 The images show the scanning electron microscope (SEM) image and corresponding EDX elemental distribution map of the hydrogen evolution electrode prepared in Example 1 of this invention after seawater electrolysis, revealing the calcium and magnesium deposition. Detailed Implementation

[0039] The technical solution of the present invention is illustrated below through specific embodiments. It should be emphasized that the embodiments are only used to explain the core concept of the present invention and do not constitute a limitation on the scope of the claims. In specific implementation, experimental parameters not explicitly marked are performed using conventional technical conditions in the art or standards recommended by equipment suppliers. Unless otherwise specified, the manufacturers of the experimental materials and instruments involved are all standardized products known in the art and available commercially.

[0040] According to a first aspect of the present invention, a method for preparing an amorphous ruthenium / manganese-doped tungsten oxide hydrogen evolution electrode resistant to calcium and magnesium deposition is provided, comprising the following steps:

[0041] Step 1: Cut the conductive substrate to the appropriate size, and clean it with hydrochloric acid, anhydrous ethanol and ultrapure water in sequence using ultrasonic cleaning. After cleaning, place it in an oven to dry for later use.

[0042] The conductive substrate is carbon paper, carbon cloth, or nickel foam. The cutting area is determined according to actual needs and requires pretreatment: ultrasonic cleaning with hydrochloric acid, ethanol, and ultrapure water for 15-25 minutes in sequence, followed by drying at 50-70℃.

[0043] Step 2: Dissolve the tungsten source and manganese source in a solvent in a certain proportion and stir thoroughly to obtain a mixed solution. Place the pretreated conductive substrate in this solution and grow a manganese-doped tungsten oxide nanoarray in situ on the conductive substrate via a hydrothermal reaction.

[0044] The tungsten source is any one of sodium tungstate, ammonium metatungstate, tungsten chloride, or sodium tungstate, and its concentration in the solution is 0.01-0.10 M;

[0045] The manganese source is any one of manganese nitrate, manganese chloride, manganese acetate, or manganese sulfate, and the final manganese doping level is controlled to be 2~8 at.% by adjusting the amount of manganese source added.

[0046] The hydrothermal reaction temperature is 160-200℃, and the hydrothermal reaction time is 12-20 h.

[0047] Step 3: Immerse the manganese-doped tungsten oxide electrode obtained in Step 2 in a precursor solution containing ruthenium salt, and load ruthenium species on the surface of manganese-doped tungsten oxide by the immersion-adsorption method to obtain a ruthenium salt / manganese-doped tungsten oxide composite electrode.

[0048] The ruthenium salt precursor is an aqueous solution of ruthenium trichloride with a molar concentration of 0.001-0.02 M; the immersion time is 5-20 min.

[0049] Step 4: Place the product obtained in Step 3 in a plasma processing device and perform plasma irradiation treatment under a specific atmosphere to transform the loaded ruthenium species into amorphous ruthenium nanoparticles and strengthen the metal-support interaction between amorphous ruthenium and manganese-doped tungsten oxide support, thereby obtaining an amorphous ruthenium-loaded manganese-doped tungsten oxide heterojunction electrode.

[0050] The atmosphere for plasma treatment is any one of argon, nitrogen, or an argon-hydrogen mixture (H2 volume fraction 5%).

[0051] The plasma treatment pressure is 10-100 Pa;

[0052] The power of the plasma treatment is 50-300 W;

[0053] The plasma treatment time is 5-15 minutes.

[0054] The present invention will be further described below with reference to specific embodiments and comparative examples.

[0055] Example 1

[0056] The method for preparing the amorphous ruthenium / manganese-doped tungsten oxide hydrogen evolution electrode provided in this embodiment includes the following steps:

[0057] 1. The nickel foam (NF) was ultrasonically cleaned several times with hydrochloric acid, ethanol, and ultrapure water, and then dried in a vacuum oven at 60°C. Next, 2 mmol of ammonium metatungstate, 0.5 mmol of manganese chloride tetrahydrate, and 30 mL of deionized water were mixed thoroughly. The homogeneous solution was transferred together with the NF into a high-pressure reactor (50 mL), and kept at 180°C for 16 hours. After the oven cooled to room temperature, the electrode was removed from the reactor, washed several times with deionized water, and then dried in an air oven at 60°C.

[0058] 2. The electrode synthesized in step 1 was immersed in a 0.01 M ruthenium trichloride solution for 5 minutes, and then dried in an oven at 60°C to obtain a ruthenium salt-loaded manganese-doped tungsten oxide electrode.

[0059] 3. The ruthenium salt-loaded manganese-doped tungsten oxide electrode synthesized in step 2 was placed in a radio frequency enhanced plasma chemical vapor deposition (RF-PECVD) system and treated with nitrogen plasma at a pressure of 60 Pa for 5 min. The radio frequency plasma discharge power was 100 W to obtain an amorphous ruthenium / manganese-doped tungsten oxide electrode.

[0060] Comparative Example 1

[0061] Preparation of tungsten oxide electrodes: Nickel foam (NF) was ultrasonically cleaned several times with hydrochloric acid, ethanol, and ultrapure water, and then dried in a vacuum oven at 60°C. Next, 2 mmol of ammonium metatungstate was mixed thoroughly with 30 mL of deionized water. The homogeneous solution was transferred together with NF to a high-pressure reactor (50 mL) and kept at 180°C for 16 hours. After the oven cooled to room temperature, the electrode was removed from the reactor, washed several times with deionized water, and then dried in an air oven at 60°C.

[0062] Comparative Example 2

[0063] Preparation of manganese-doped tungsten oxide electrodes: Nickel foam (NF) was ultrasonically cleaned several times with hydrochloric acid, ethanol, and ultrapure water, and then dried in a vacuum oven at 60 °C. Next, 2 mmol of ammonium metatungstate was mixed thoroughly with 30 mL of deionized water. The homogeneous solution was transferred together with NF to a high-pressure reactor (50 mL) and kept at 180 °C for 16 hours. After the oven cooled to room temperature, the electrode was removed from the reactor, washed several times with deionized water, and then dried in an air oven at 60 °C.

[0064] Comparative Example 3

[0065] Preparation of amorphous ruthenium / tungsten oxide electrodes: Nickel foam (NF) was ultrasonically cleaned several times with hydrochloric acid, ethanol, and ultrapure water, and then dried in a vacuum oven at 60 °C. Next, 2 mmol of ammonium metatungstate was mixed with 30 mL of deionized water. The homogeneous solution was transferred together with NF to a high-pressure reactor (50 mL) and kept at 180 °C for 16 hours. After the oven cooled to room temperature, the electrode was removed from the reactor, washed several times with deionized water, and then dried in an air oven at 60 °C. Subsequently, it was immersed in 0.01 M ruthenium trichloride solution for 5 minutes, and then dried in an oven at 60 °C. The dried sample was then treated with 100 W radio frequency plasma discharge power for 5 minutes under a nitrogen atmosphere of 60 Pa to obtain the amorphous ruthenium / tungsten oxide electrode.

[0066] To verify the technical effects of each embodiment and comparative example, the following experiments were conducted.

[0067] Material characterization analysis:

[0068] 1. Phase composition (corresponding to) Figure 1 )

[0069] The phase composition of the amorphous ruthenium / manganese-doped tungsten oxide hydrogen evolution electrode prepared in Example 1 was analyzed by X-ray diffraction (XRD). Figure 1 As shown, the diffraction peaks at 23.2°, 28.1°, and 36.8° belong to the hexagonal tungsten trioxide phase (PDF# 85-2460), and no characteristic peaks belonging to manganese-related phases were observed, indicating that manganese has been successfully doped into the tungsten oxide lattice. It is noteworthy that no characteristic diffraction peaks of metallic ruthenium were observed in the full spectrum, possibly due to its amorphous state or limitations imposed by the detection methods.

[0070] 2. Microscopic morphology (corresponding to) Figure 2 )

[0071] The surface morphology of the catalyst layer prepared in Example 1 was characterized using scanning electron microscopy (SEM). Figure 2 As shown, manganese-doped tungsten oxide exhibits a uniform nanorod morphology with a diameter of approximately 200 nm. The nanorods interweave to form a loose, porous network structure. This porous structure facilitates electrolyte penetration and rapid bubble release, while also exposing more active sites. After loading amorphous ruthenium, the nanorod surface becomes slightly rougher, but the overall morphology remains largely unchanged, indicating that the introduction of ruthenium does not disrupt the nanostructure of manganese-doped tungsten oxide.

[0072] 3. Microstructure and Amorphous State Verification (corresponding to) Figure 3 )

[0073] The microstructure of the amorphous ruthenium / manganese-doped tungsten oxide composite prepared in Example 1 was further characterized using transmission electron microscopy (TEM) and selected area electron diffraction (SAED). High-resolution TEM images ( Figure 3 a) shows that the manganese-doped tungsten oxide nanorods have clear lattice fringes with a crystal plane spacing of approximately 0.383 nm, corresponding to the (002) crystal plane of hexagonal tungsten trioxide. Uniformly distributed fine ruthenium nanoparticles are observed on the surface of the manganese-doped tungsten oxide nanorods. Notably, these ruthenium nanoparticles do not show any obvious diffraction rings or diffraction spots in the SAED pattern. Figure 3 (b) Only diffraction rings belonging to the manganese-doped tungsten oxide support were observed, further confirming, combined with XRD results, that the supported ruthenium existed in an amorphous state. Amorphous ruthenium possesses numerous structural defects and dangling bonds, providing abundant catalytic active sites for the hydrogen evolution reaction.

[0074] 4. Electrochemical performance analysis (corresponding to) Figure 4 )

[0075] Linear sweep voltammetry (LSV) tests were performed in natural seawater on the amorphous ruthenium / manganese-doped tungsten oxide hydrogen evolution electrode prepared in Example 1 and the electrodes of Comparative Examples 1-3 using a standard three-electrode system at a scan rate of 5 mV / s. Figure 4 As shown, Example 1 exhibits optimal HER activity at 100 mA cm⁻¹. -2 The overpotential at current density is only 181 mV, which is significantly better than that of Comparative Example 1 (WO3, 361 mV@100 mA cm⁻¹). -2 Comparative Example 2 (Mn-doped WO3, 344 mV @ 100 mA cm⁻¹) -2 ) and Comparative Example 3 (amorphous Ru / WO3, 283 mV@100 mA cm⁻¹) -2 This result indicates that the synergistic effect between amorphous ruthenium and Mn-doped WO3 significantly improves hydrogen evolution kinetics. The oxygen vacancies introduced by Mn doping increase the number of active sites, while amorphous ruthenium provides abundant active sites and optimizes HER kinetics.

[0076] 5. Stability verification (corresponding) Figure 5 )

[0077] A standard three-electrode system was used to conduct constant current electrolysis tests (current density 200 mA cm⁻¹) on the electrodes of Example 1 and Comparative Examples 1-3 in natural seawater. -2 To assess its long-term stability. Figure 5As shown, Example 1 can operate continuously for 100 hours with overpotential fluctuations of <5%, demonstrating excellent stability in natural seawater electrolysis. In contrast, Comparative Example 3 showed significant performance degradation after 40 hours. The superior stability of Example 1 is attributed to the in-situ constructed acidified microenvironment at the ruthenium / amorphous manganese-doped tungsten oxide interface, which effectively inhibits the deposition of calcium and magnesium hydroxides, avoiding blockage and deactivation of active sites.

[0078] 6. Resistance to calcium / magnesium precipitation (corresponding to) Figure 6 )

[0079] In the hydrogen evolution reaction at the cathode, the abundant calcium and magnesium ions in natural seawater easily generate Ca(OH)₂ and Mg(OH)₂ precipitates due to the local pH increase. These precipitates can adhere to or even completely cover the active sites, thus severely impairing the hydrogen evolution performance of the cathode catalyst. To verify the anti-calcium and magnesium deposition ability of the electrode of this invention, the electrode of Example 1 was subjected to a 200 mA cm⁻¹ solution of natural seawater. -2 After 24 hours of constant current electrolysis, the electrode surface was characterized using SEM and corresponding EDX elemental distribution. Figure 6 As shown, the electrode surface remained clean after electrolysis, with clearly visible nanorod-like morphology and no obvious granular deposits observed. EDX elemental distribution maps showed extremely weak Ca and Mg elemental signals on the electrode surface, with no significant difference compared to before electrolysis, indicating almost no calcium and magnesium deposition on the electrode surface. This result fully demonstrates the excellent resistance to calcium and magnesium deposition in the electrode of this invention during seawater electrolysis. The mechanism is attributed to the in-situ acidified microenvironment constructed at the amorphous ruthenium / manganese-doped tungsten oxide interface, which maintains the local pH of the electrode surface at a low level, inhibiting Ca deposition at its source. 2+ and Mg 2+ Thermodynamic conditions for the formation of hydroxide precipitates.

[0080] In summary, the amorphous ruthenium / manganese-doped tungsten oxide hydrogen evolution electrode prepared in this invention exhibits excellent HER activity (100 mA cm⁻¹) in natural seawater electrolyte. -2 Overpotential of only 181 mV), long-term stability (200 mA cm⁻¹) -2 With its ability to operate continuously for 100 hours and excellent resistance to calcium and magnesium deposition, it provides a low-cost and highly durable solution for direct seawater electrolysis hydrogen production, which can strongly promote the industrialization of marine hydrogen energy, and is especially suitable for off-grid hydrogen production scenarios coupled with wind power / photovoltaic power.

Claims

1. An amorphous ruthenium / manganese-doped tungsten oxide hydrogen evolution electrode resistant to calcium and magnesium deposition, characterized in that, The electrode comprises: a) a conductive substrate; b) a manganese-doped tungsten oxide matrix material grown on the surface of the conductive substrate; c) amorphous ruthenium active sites uniformly loaded on the surface of the manganese-doped tungsten oxide matrix; d) the electrode is a multi-level micro / nano array through-pore structure with a dynamic acid-like micro-interface, which neutralizes OH⁻ generated by hydrogen evolution at the cathode and inhibits the scaling and precipitation of calcium and magnesium ions on the electrode surface.

2. The amorphous ruthenium / manganese-doped tungsten oxide hydrogen evolution electrode resistant to calcium and magnesium deposition according to claim 1, characterized in that, The conductive substrate is one of carbon paper, carbon cloth, or nickel foam.

3. The amorphous ruthenium / manganese-doped tungsten oxide hydrogen evolution electrode resistant to calcium and magnesium deposition according to claim 1, characterized in that, In the manganese-doped tungsten oxide matrix, the molar percentage of manganese doping is 2~8 at.%; the ruthenium is in amorphous form, and the ruthenium loading is 1.5~5 wt.%.

4. The amorphous ruthenium / manganese-doped tungsten oxide hydrogen evolution electrode resistant to calcium and magnesium deposition according to claim 1, characterized in that, The multi-level micro-nano array is composed of a nanorod backbone and nanoparticle branches, forming a continuous and interconnected multi-level pore structure. The pore structure accelerates seawater mass transfer and rapid desorption of hydrogen bubbles, avoids local OH⁻ accumulation, helps maintain a stable local acidic environment on the electrode surface, and further blocks the precipitation and growth channels of calcium and magnesium sparingly soluble salts.

5. The method for preparing an amorphous ruthenium / manganese-doped tungsten oxide hydrogen evolution electrode resistant to calcium and magnesium deposition as described in any one of claims 1-4, characterized in that, Includes the following steps: Step 1: Cut the selected conductive substrate into 2 cm × 4 cm sizes, and ultrasonically clean it for 15~25 min in sequence with hydrochloric acid, anhydrous ethanol and ultrapure water to remove surface oil, impurities and oxide layer. After cleaning, place it in an oven at 50~70℃ to dry for later use. Step 2: Prepare a mixed precursor aqueous solution containing tungsten source and manganese source, immerse the pretreated conductive substrate from Step 1 in the mixed precursor solution, and carry out a hydrothermal reaction to grow a manganese-doped tungsten oxide array in situ on the surface of the conductive substrate; after the reaction is completed, remove the electrode, rinse with ultrapure water, and dry at 60~80℃. Step 3: Immerse the manganese-doped tungsten oxide array electrode obtained in Step 2 in the ruthenium salt precursor impregnation solution to adsorb and bind the ruthenium salt through impregnation, and dry at 60~80℃. Step 4: The ruthenium salt-loaded manganese-doped tungsten oxide obtained in Step 3 is subjected to plasma treatment to finally obtain an amorphous ruthenium-loaded manganese-doped tungsten oxide seawater anti-precipitation hydrogen evolution cathode electrode.

6. The preparation method according to claim 5, characterized in that: In step 2, the tungsten source is any one of sodium tungstate, ammonium metatungstate, or tungsten chloride, with a molar concentration of 0.01~0.10 M; the manganese source is any one of manganese nitrate, manganese chloride, manganese acetate, or manganese sulfate; the hydrothermal reaction temperature is 160~200℃, and the reaction time is 12~20 h.

7. The preparation method according to claim 5, characterized in that: In step 3, the ruthenium salt precursor is an aqueous solution of ruthenium trichloride with a molar concentration of 0.001-0.02 M; the immersion time is 5-20 min.

8. The preparation method according to claim 5, characterized in that: In step 4, the plasma treatment atmosphere is any one of nitrogen, argon, or a hydrogen-argon mixture (H2 volume fraction 5%); the plasma treatment pressure is 10-100 Pa; the plasma power is 50-300 W; and the plasma treatment time is 5-15 min.

9. The application of the amorphous ruthenium / manganese-doped tungsten oxide hydrogen evolution electrode resistant to calcium and magnesium deposition as described in any one of claims 1 to 4 in seawater electrolysis, characterized in that: The electrode serves as the cathode catalyst for seawater electrolysis, used in real seawater systems for the electrocatalytic hydrogen evolution reaction; it can suppress the concentration of Ca in seawater under high current density conditions. 2+ Mg 2+ Hydroxide deposition is formed; high current density seawater hydrogen evolution is achieved at low overpotential; no significant surface precipitation or activity decay occurs during long-term cycling at high current density; Faraday efficiency ≥98%; suitable for industrial-scale seawater electrolysis hydrogen production.

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