A lanthanum-hafnium-tantalum-tungsten multi-component co-doped ruthenium dioxide catalyst, its preparation method, and its application in the acidic oxygen evolution reaction.

Abstract

This invention relates to a lanthanum-hafnium-tantalum-tungsten multi-component co-doped ruthenium dioxide catalyst, its preparation method, and its application in acidic oxygen evolution reaction (OER). The preparation method involves dissolving ruthenium, lanthanum, hafnium, tantalum, and tungsten sources in a solvent, removing the solvent to obtain a precursor powder. A molten salt is then heated to melt, followed by the addition of the obtained precursor powder, and the reaction is carried out at a constant temperature. The resulting reaction solution is subjected to solid-liquid separation, and the solid phase is collected; the obtained solid phase is the lanthanum-hafnium-tantalum-tungsten multi-component co-doped ruthenium dioxide acidic OER catalyst. The catalyst obtained by this invention exhibits excellent OER catalytic performance in a 0.5 mol / L H₂SO₄ electrolyte at 10 mA / cm⁻¹. 2 The oxygen evolution overpotential is only 158 mV at current density, and it can achieve long-term stable operation for more than 1800 hours.

Description

Technical Field

[0001] This invention relates to the field of catalyst technology, and in particular to a lanthanum-hafnium-tantalum-tungsten multi-component co-doped ruthenium dioxide catalyst, its preparation method, and its application in the acidic oxygen evolution reaction. Background Technology

[0002] Hydrogen energy is an ideal green and clean energy source, meeting the demands of ecological environmental protection and low-carbon development. Proton exchange membrane electrolysis (PEMWE) has become one of the mainstream development directions for hydrogen production through water electrolysis due to its advantages such as high current density, fast start-up and shutdown response, and high hydrogen purity. Currently, PEMWE technology commonly uses the precious metal iridium dioxide (IrO2) as the anode catalyst material, but its high cost severely limits its large-scale application. Ruthenium dioxide (RuO2) combines excellent electrocatalytic activity with low cost, making it an ideal candidate material to replace IrO2. However, RuO2's poor stability limits its large-scale commercial application in PEMWE. This is mainly due to the synergistic effect of two deactivation mechanisms: On the one hand, during the acidic oxygen evolution reaction, RuO2 tends to follow the lattice oxygen oxidation mechanism (LOM), which easily induces the generation of oxygen vacancies, destroys the intrinsic coordination structure of the crystal, and leads to structural collapse; on the other hand, under the strong oxidation environment of the anodic potential, Ru sites are very prone to over-oxidation, and the low-coordination, highly active Ru atoms in the lattice are continuously oxidized into high-valence soluble species, namely Ru 8+ The continuous leaching and loss of ionic forms leads to irreversible loss of active sites. Researchers have conducted extensive work to address this deactivation mechanism. To suppress the LOM (Left-Induced Malfunction) mechanism, Guo's team synthesized a lead-doped ruthenium dioxide catalyst (Pb-RuO2) by doping RuO2 with lead (Pb), an element with a large ionic radius. They utilized lattice stress to narrow the oxygen atom migration channels and reduce the covalent nature of the Ru-O bond, thereby inhibiting the participation of lattice oxygen in the reaction and structural collapse (Nature Communications, 2024, 15, 9774). Furthermore, they addressed the issue of RuO2's tendency to undergo peroxidation to generate soluble high-valence Ru... 8+ To address the performance degradation issue, Rao's team synthesized a cobalt-doped ruthenium dioxide catalyst (Co-RuO2) by introducing single-atom cobalt (Co) onto the RuO2 surface. The surface oxidation state of Ru is reduced through the electron transfer effect from Co to Ru, while a local Ru-O-Co coordination structure is formed to enhance the Ru-O lattice bond strength, thus significantly suppressing Ru peroxidation and dissolution (Advanced Functional Materials, 36, e23636).

[0003] While existing research strategies have made significant progress in improving catalytic performance, most studies only target one aspect of the two deactivation mechanisms of RuO2 catalysts: structural collapse caused by the LOM mechanism or dissolution and loss induced by Ru peroxidation. There is a lack of simultaneous suppression of both deactivation mechanisms. These strategies often compromise on one aspect: focusing on suppressing the LOM mechanism makes it difficult to effectively stabilize the Ru valence state; focusing on suppressing Ru peroxidation may result in insufficient control over lattice oxygen migration. This makes it difficult for RuO2 regulated by single strategies to achieve a balance between activity and stability under long-term PEMWE conditions, which has become a key bottleneck that urgently needs to be overcome for the industrial application of ruthenium-based catalysts for the acidic oxygen evolution reaction. Summary of the Invention

[0004] To address the above technical problems, this invention provides a multi-element doping strategy targeting the deactivation mechanism of Ru-based catalysts to improve the acidic oxygen evolution reaction (PEMWE) performance of RuO2. Another objective of this invention is to provide a method for preparing a single-phase RuO2 with uniform multi-element doping. A further objective of this invention is to provide the application of lanthanum-hafnium-tantalum-tungsten multi-element co-doped ruthenium dioxide in the acidic oxygen evolution reaction and PEMWE.

[0005] The first objective of this invention is to provide a method for preparing a lanthanum-hafnium-tantalum-tungsten multi-component co-doped ruthenium dioxide catalyst, comprising the following steps: (1) Ruthenium source, lanthanum source, hafnium source, tantalum source and tungsten source are added to a solvent and mixed and dissolved, and the solvent is removed to obtain precursor powder; (2) The molten salt is heated and melted, and then the precursor powder obtained in step (1) is added and reacted at a constant temperature. The resulting reaction solution is separated into solid and liquid phases and the solid phase is obtained. The solid phase is the lanthanum hafnium tantalum tungsten multi-component co-doped ruthenium dioxide acid oxygen evolution catalyst (LHTW-RuO2).

[0006] In some embodiments of the present invention, in step (1), the mass ratio of the ruthenium source, lanthanum source, hafnium source, tantalum source and tungsten source is 40~50:8~10:3~6:3~7:3~7.

[0007] In some embodiments of the present invention, in step (1), the ruthenium source is selected from one or more of ruthenium trichloride (RuCl3), ruthenium trichloride hydrate (RuCl3.xH2O) and ruthenium acetylacetone (Ru(acac)2); The lanthanum source is selected from one or more of lanthanum trichloride hexahydrate (LaCl3･6H2O), anhydrous lanthanum trichloride (LaCl3), and lanthanum acetylacetone (La(acac)3); The hafnium source is selected from hafnium tetrachloride (HfCl4) and / or hafnium nitrate (Hf(NO3)4). The tantalum source is selected from tantalum pentachloride (TaCl5) and / or tantalum nitrate (Ta(NO3)5). The tungsten source is selected from tungsten hexachloride (WCl6) and / or tungsten acetylacetone (W(acac)4). The solvent is selected from ethanol and / or isopropanol.

[0008] In some embodiments of the present invention, in step (2), the heating and melting conditions are: heating rate of 5~10℃ / min and temperature of 300~400°C.

[0009] In some embodiments of the present invention, in step (2), the temperature of the isothermal reaction is 300~400°C and the reaction time is 2~4h.

[0010] In some embodiments of the present invention, in step (2), the mass ratio of molten salt sodium nitrate to precursor powder is 40:1 to 100:1; the molten salt is selected from one or more of sodium nitrate, sodium chloride, and potassium nitrate.

[0011] The second objective of this invention is to provide a lanthanum-hafnium-tantalum-tungsten multi-component co-doped ruthenium dioxide acidic oxygen evolution catalyst, prepared by the aforementioned preparation method.

[0012] A third objective of this invention is to provide the application of the aforementioned lanthanum-hafnium-tantalum-tungsten multi-component co-doped ruthenium dioxide catalyst in the acidic oxygen evolution reaction.

[0013] In some embodiments of the present invention, the amount of the lanthanum-hafnium-tantalum-tungsten multi-component co-doped ruthenium dioxide acidic oxygen evolution catalyst is 1 mg / cm³. 2 ~4mg / cm 2 .

[0014] In some embodiments of the present invention, the acidic oxygen evolution reaction is carried out using a three-electrode system, wherein a carbon rod is used as the counter electrode, a saturated calomel electrode is used as the reference electrode, and an electrode containing a lanthanum-hafnium-tantalum-tungsten multi-component co-doped ruthenium dioxide oxygen evolution catalyst is used as the working electrode.

[0015] The technical solution of the present invention has the following advantages compared with the prior art: This invention successfully prepared lanthanum-hafnium-tantalum-tungsten multi-element co-doped ruthenium dioxide via the molten salt method, providing a method for synthesizing multi-element doped ruthenium dioxide as a catalyst for acidic oxygen evolution reaction.

[0016] This invention provides the application of lanthanum-hafnium-tantalum-tungsten multi-component co-doped ruthenium dioxide as a catalyst for the acidic oxygen evolution reaction (OER). This catalyst exhibits excellent OER catalytic performance in a 0.5 mol / L H₂SO₄ electrolyte at 10 mA / cm⁻¹. 2The oxygen evolution overpotential at the current density is only 158 mV, and it can achieve long-term stable operation for more than 1800 hours. Compared with the overpotentials of 188 mV for Pb-RuO2 and 206 mV for Co-RuO2 reported in the literature, the catalytic activity of this invention is significantly improved. In terms of stability testing, the lanthanum-hafnium-tantalum-tungsten multi-component co-doped ruthenium dioxide can operate stably for 1800 hours without significant degradation. The continuous operating times of Pb-RuO2 and Co-RuO2 are 1100 hours and 800 hours, respectively. The stability time of this invention is improved by more than 50% compared with similar catalysts.

[0017] This invention incorporates four elements—lanthanum, hafnium, tantalum, and tungsten—into a ruthenium dioxide lattice. 1. Lanthanum's atomic radius is much larger than ruthenium's. After doping, it exerts a strong compressive effect on the original crystal lattice, inducing lattice distortion and stress, effectively reducing the generation and quantity of oxygen vacancies in the catalyst, thereby inhibiting LOM (Left-of-Morph) formation during the acidic oxygen evolution reaction. 2. Tantalum and tungsten are both high-valence metals. Co-doping them into the RuO2 lattice utilizes the electronic regulation effect of high-valence heteroatoms to effectively adjust the electron cloud density and valence distribution of ruthenium active sites, reducing excessive oxidation and dissolution deactivation of ruthenium sites. 3. Hafnium, as a transitional dopant, mainly plays an intermediate transitional regulatory role in the multi-element doping system. The introduction of hafnium effectively increases the overall configurational entropy of the RuO2 crystal, further stabilizing the overall lattice structure. Attached Figure Description

[0018] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings, wherein... Figure 1 This is a transmission electron microscope (TEM) image of the material obtained in Example 1 (LHTW-RuO2).

[0019] Figure 2 This is a high-resolution transmission electron microscope (HR-TEM) image of the material obtained in Example 1 (LHTW-RuO2).

[0020] Figure 3 This is the energy dispersive X-ray spectral elemental distribution map (EDS-Mapping) of the material obtained in Example 1 (LHTW-RuO2).

[0021] Figure 4 This is a scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDS) image of the material obtained in Example 1 (LHTW-RuO2).

[0022] Figure 5 These are X-ray diffraction (XRD) patterns and simulated spectra of Example 1 (LHTW-RuO2) and Comparative Example 4 (C-RuO2).

[0023] Figure 6 The linear sweep voltammetry and fitting curves of Example 1 and Comparative Example 1 (LHTW-RuO2), Comparative Example 1 (TW-RuO2), Comparative Example 2 (L-RuO2), Comparative Example 3 (RuO2) and Comparative Example 4 (C-RuO2) are shown. Figure 7 These are the electrochemical impedance spectra and fitting curves of the samples corresponding to Example 1 (LHTW-RuO2), Comparative Example 3 (RuO2), and Comparative Example 4 (C-RuO2).

[0024] Figure 8 The corresponding samples of Example 1 (LHTW-RuO2), Comparative Example 3 (RuO2), and Comparative Example 4 (C-RuO2) are at 10 mA / cm 2 Stability test results under current.

[0025] Figure 9 This describes the actual application performance of Example 1 (LHTW-RuO2) and Comparative Example 3 (RuO2) in PEMWE. Detailed Implementation

[0026] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0027] The present invention achieves its objective by employing the following technical solution: Lanthanum-hafnium-tantalum-tungsten multi-component co-doped ruthenium dioxide was prepared via a molten salt method. The method is as follows: Ruthenium salt, lanthanum salt, hafnium salt, tantalum salt, and tungsten salt were weighed into small beakers, dissolved in ethanol, and the ethanol was evaporated to dryness to obtain precursor powder. The obtained precursor powder and molten salt were added to a crucible, and the mixture was kept at 350°C for 3 hours in a muffle furnace. After natural cooling, the mixture was removed, washed, and dried to obtain lanthanum-hafnium-tantalum-tungsten multi-component co-doped ruthenium dioxide (LHTW-RuO2). Example 1

[0028] This embodiment provides a method for preparing a lanthanum-hafnium-tantalum-tungsten multi-component co-doped ruthenium dioxide acidic oxygen evolution catalyst, as detailed below: (1) Weigh 41 mg of ruthenium trichloride (RuCl3), 10 mg of lanthanum trichloride hexahydrate (LaCl3･6H2O), 3.2 mg of hafnium tetrachloride (HfCl4), 3.6 mg of tantalum pentachloride (TaCl5), and 3.9 mg of tungsten hexachloride (WCl6) into a 50 mL beaker, add 2 mL of ethanol to dissolve, then sonicate for 1 h, and evaporate the ethanol to dryness to obtain the precursor powder.

[0029] (2) Add 5g of sodium nitrate (NaNO3) to a 15mL crucible, heat at 10℃ / min until 350°C, and add the precursor powder obtained in step (1) after the NaNO3 melts. Continue to keep warm at 350°C for 3h. After the reaction is completely cooled to room temperature, dissolve the sample in the crucible in deionized water to obtain a turbid black solution. Filter the solution and wash it 4-5 times. Remove the filter paper and dry it in an oven at 60℃ for 6h. Scrape off the filter paper to obtain lanthanum hafnium tantalum tungsten multi-component co-doped ruthenium dioxide powder (LHTW-RuO2).

[0030] The obtained lanthanum-hafnium-tantalum-tungsten multi-component co-doped ruthenium dioxide was structurally characterized, and the results are shown in the figure. Figures 1-5 .

[0031] Figure 1 This is a transmission electron microscope (TEM) image of the material obtained in Example 1 (LHTW-RuO2). As can be seen from the image, the sample exhibits a two-dimensional layered structure. Figure 2 This is a high-resolution transmission electron microscope (HR-TEM) image of the material obtained in Example 1 (LHTW-RuO2). As can be seen from the image, the sample exhibits clear and regular lattice fringes, and its lattice spacing is measured to be approximately 0.330 nm, corresponding to the (110) crystal plane of standard ruthenium dioxide; Figure 3 This is the energy-dispersive X-ray spectral elemental distribution map (EDS-Mapping) of the material obtained in Example 1 (LHTW-RuO2). As can be seen from the figure, the elements are uniformly distributed in the obtained material. Figure 4 This is a scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDS) image of the material obtained in Example 1 (LHTW-RuO2). As can be seen from the image, the atomic ratios of ruthenium / lanthanum / hafnium / tantalum / tungsten / oxygen in the obtained material are 31.8 / 2.7 / 2.8 / 1.3 / 2.7 / 58.6, respectively. Figure 5 These are the X-ray diffraction (XRD) patterns and simulated spectra of Example 1 (LHTW-RuO2) and Comparative Example 4 (C-RuO2). The refined results show that the cell volume of LHTW-RuO2 is 80.55 Å. The experimental and calculated spectra after structural refinement agree well. The refined results for C-RuO2 show a cell volume of 62.42 Å. This indicates that lanthanum, hafnium, tantalum, and tungsten were successfully incorporated into ruthenium dioxide, leading to cell volume expansion. The experimental and calculated spectra after structural refinement also agree well.

[0032] Comparative Example 1 This comparative example provides a method for preparing a tantalum-tungsten-doped ruthenium dioxide acidic oxygen evolution catalyst, as detailed below: (1) Weigh 41 mg of ruthenium trichloride (RuCl3), 3.6 mg of tantalum pentachloride (TaCl5), and 3.9 mg of tungsten hexachloride (WCl6) into a 50 mL beaker, add 2 mL of ethanol to dissolve, then sonicate for 1 h, and evaporate the ethanol to dryness to obtain the precursor powder.

[0033] (2) Add 5g of sodium nitrate (NaNO3) to a 15mL crucible, and heat at 10℃ / min until 350°C. After the NaNO3 melts, add the precursor powder obtained in step (1) and continue to keep warm at 350°C for 3h. After the reaction is completely cooled to room temperature, dissolve the sample in the crucible in deionized water to obtain a turbid black solution. Filter the black solution and wash it 4-5 times. Remove the filter paper and dry it in an oven at 60℃ for 6h. Scrape off the filter paper to obtain tantalum-tungsten doped ruthenium dioxide (TW-RuO2).

[0034] Comparative Example 2 This comparative example provides a method for preparing a lanthanum-doped ruthenium dioxide acidic oxygen evolution catalyst, as detailed below: (1) Weigh 41 mg of ruthenium trichloride (RuCl3) and 10 mg of lanthanum trichloride hexahydrate (LaCl3･6H2O) into a 50 mL beaker, add 2 mL of ethanol to dissolve, then sonicate for 1 h, and evaporate the ethanol to dryness to obtain the precursor powder.

[0035] (2) Add 5g of sodium nitrate (NaNO3) to a 15mL crucible, heat at 10℃ / min until 350°C, and add the collected precursor powder after the NaNO3 melts. Continue to keep warm at 350°C for 3h. After the reaction is complete and cooled to room temperature, dissolve the sample in the crucible in deionized water to obtain a turbid black solution. Filter the black solution and wash it 4-5 times. Remove the filter paper and dry it in an oven at 60℃ for 6h. Scrape off the filter paper to obtain lanthanum-doped ruthenium dioxide (L-RuO2).

[0036] Comparative Example 3 This comparative example provides a method for preparing an acidic oxygen evolution catalyst of ruthenium dioxide, as detailed below: Weigh 41 mg of RuCl3 into a 50 mL beaker, add 2 mL of ethanol to dissolve it, then sonicate for 1 h, and evaporate the ethanol to dryness to obtain a powder. Add 5 g of sodium nitrate (NaNO3) to a 15 mL crucible, heat at 10 °C / min until it reaches 350 °C, and after the NaNO3 melts, add the collected precursor powder, and continue to maintain the temperature at 350 °C for 3 h. After the reaction is complete and cooled to room temperature, dissolve the sample in deionized water to obtain a turbid black solution. Filter the black solution, wash 4-5 times, remove the filter paper, dry it in an oven at 60 °C for 6 h, and scrape it off to obtain RuO2.

[0037] Comparative Example 4 This comparative example used a commercial ruthenium oxide catalyst (C-RuO2), purchased from Innochem Technology Co., Ltd., with a purity of 99.9%.

[0038] To evaluate the oxygen evolution reaction performance of Examples 1-4 under acidic conditions, electrocatalytic performance tests were conducted on them. The specific test steps are as follows: (1) Weigh 5 mg of the catalysts obtained in Examples 1-4 and 1-4 respectively, and ultrasonically disperse them in 2 mL of isopropanol. Add 5 mg of conductive carbon black to improve conductivity, and then add 40 μL of perfluorosulfonic acid (5 wt%) as a binder. Continue ultrasonication for more than 1 hour to obtain a uniformly mixed suspension. Use a pipette to transfer 20 μL of the suspension onto a surface with an area of ​​0.196 cm². 2 The working electrode is obtained by air-drying the glassy carbon electrode.

[0039] (2) To test the linear sweep voltammetric performance of the catalysts obtained in Examples 1 and 4, a three-electrode mode was used in a 0.5 M sulfuric acid (H₂SO₄) electrolyte with a carbon rod as the counter electrode and a saturated calomel electrode as the reference electrode. All potentials were converted to reversible hydrogen electrode potentials (RHE). High-purity oxygen (O₂) was continuously bubbled into the electrolyte solution for 30 min before testing. The anodic linear sweep voltammetric rate was controlled at 5 mV / s, and the IR compensation was 95%. The experimental results are shown in […]. Figure 6 As shown in the figure, LHTW-RuO2 has the smallest overpotential and the best oxygen evolution reaction performance.

[0040] (3) To test the electrochemical impedance performance of the catalysts obtained in Examples 1, 3, and 4, a three-electrode mode was used in 0.5 M H₂SO₄ with a carbon rod as the counter electrode and a saturated calomel electrode as the reference electrode, and all potentials were converted to RHE. High-purity O₂ was continuously bubbled into the electrolyte solution for 30 min before the test. The frequency was set from 0.1 to 100,000 Hz, and the test voltage was 1.45 V. The experimental results are shown in […]. Figure 7 As can be seen from the figure, LHTW-RuO2 exhibits the smallest electrochemical impedance, demonstrating that it has the fastest reaction kinetic rate and electron transport capability.

[0041] (4) To test the stability of the catalysts obtained in Example 1, Comparative Example 3, and Comparative Example 4, a three-electrode mode was used in 0.5 M H₂SO₄ with a carbon rod as the counter electrode and a saturated calomel electrode as the reference electrode, and all potentials were converted to RHE. High-purity O₂ was continuously bubbled into the electrolyte solution for 30 min before the test, and the potentials were measured at 10 mA / cm⁻¹ using a chronopotentiometric method. 2 Long-term stability tests were conducted at the specified current density. Experimental results are shown below. Figure 8As can be seen from the figure, the LHTW-RuO2 catalyst exhibits the longest electrochemical working time, demonstrating its best stability.

[0042] (5) To test the PEMWE performance of the catalysts obtained in Example 1 and Comparative Example 3, respectively, Example 1 and Comparative Example 3 were used as PEMWE anode oxygen evolution reaction catalysts, and commercial platinum / carbon (Pt / C) was used as cathode hydrogen evolution reaction catalysts to prepare membrane electrode assemblies (MEAs); the loading of the anode material was controlled at 2 mg / cm³. 2 The cathode Pt loading is 0.3 mg / cm³. 2 A Nafion proton exchange membrane was used as the electrolyte membrane, and an MEA (Medium Electrolyte Assembly) was assembled through coating, drying, and hot pressing processes. This MEA was then matched with a titanium felt gas diffusion layer and assembled into a PEM (Potential Electrolyte Mixture) single-cell electrolyzer. The PEMWE (Potential Electrolyte Weighing) single-cell polarization curve was measured to characterize the actual electrolyzer performance under operating conditions. Experimental results are shown below. Figure 9 As can be seen from the figure, when LHTW-RuO2 is used as the cation exchanger for oxygen evolution, the electrolyzer exhibits a significantly reduced cell voltage across the entire current density range, demonstrating excellent activity in hydrogen production through water electrolysis. This invention meets the core requirements for continuous industrial production of PEMWE and possesses significant application value and broad development potential in the industrialization process of large-scale green hydrogen production.

[0043] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for preparing a lanthanum-hafnium-tantalum-tungsten multi-component co-doped ruthenium dioxide catalyst, characterized in that, Includes the following steps: (1) Ruthenium source, lanthanum source, hafnium source, tantalum source and tungsten source are added to a solvent and mixed and dissolved, and the solvent is removed to obtain precursor powder; (2) The molten salt is heated and melted, and then the precursor powder obtained in step (1) is added and reacted at a constant temperature. The resulting reaction solution is separated into solid and liquid phases and the solid phase is obtained. The solid phase is the lanthanum hafnium tantalum tungsten multi-component co-doped ruthenium dioxide acidic oxygen evolution catalyst.

2. The preparation method according to claim 1, characterized in that, In step (1), the mass ratio of the ruthenium source, lanthanum source, hafnium source, tantalum source and tungsten source is 40~50:8~10:3~6:3~7:3~7.

3. The preparation method according to claim 1, characterized in that, In step (1), the ruthenium source is selected from one or more of ruthenium trichloride, ruthenium trichloride hydrate, and ruthenium acetylacetone; The lanthanum source is selected from one or more of lanthanum trichloride hexahydrate, anhydrous lanthanum trichloride, and lanthanum acetylacetonate. The hafnium source is selected from hafnium tetrachloride and / or hafnium nitrate. The tantalum source is selected from tantalum pentachloride and / or tantalum nitrate. The tungsten source is selected from tungsten hexachloride and / or tungsten acetylacetone; The solvent is selected from ethanol and / or isopropanol.

4. The preparation method according to claim 1, characterized in that, In step (2), the heating and melting conditions are: heating rate of 5~10℃ / min and temperature of 300~400°C.

5. The preparation method according to claim 1, characterized in that, In step (2), the temperature of the isothermal reaction is 300~400°C and the reaction time is 2~4h.

6. The preparation method according to claim 1, characterized in that, In step (2), the mass ratio of molten salt to precursor powder is 40:1 to 100:1; the molten salt is selected from one or more of sodium nitrate, sodium chloride, and potassium nitrate.

7. A lanthanum-hafnium-tantalum-tungsten multi-component co-doped ruthenium dioxide catalyst, characterized in that, Prepared by the preparation method according to any one of claims 1 to 6.

8. The application of the lanthanum-hafnium-tantalum-tungsten multi-component co-doped ruthenium dioxide catalyst according to claim 7 in the acidic oxygen evolution reaction.

9. The application according to claim 8, characterized in that, The amount of the lanthanum-hafnium-tantalum-tungsten multi-component co-doped ruthenium dioxide catalyst is 1 mg / cm³. 2 ~4mg / cm 2 .

10. The application according to claim 8, characterized in that, The acidic oxygen evolution reaction is carried out using a three-electrode system, in which a carbon rod is used as the counter electrode, a saturated calomel electrode is used as the reference electrode, and an electrode containing a lanthanum-hafnium-tantalum-tungsten multi-component co-doped ruthenium dioxide oxygen evolution catalyst is used as the working electrode.

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