A Ru-RE2O3 catalyst, its preparation method and application

Abstract

The application discloses a Ru-RE2O3 catalyst and a preparation method and application thereof, and the Ru-RE2O3 catalyst comprises a rare earth metal oxide RE2O3 shell and Ru inside. The catalyst is prepared from a carbon sphere carrier, a ruthenium salt and a rare earth metal salt through first calcination and second calcination. The first calcination is used for converting the ruthenium salt and the rare earth metal salt into corresponding oxides, and the second calcination is carried out under a reducing protective gas atmosphere, and the ruthenium oxide is selectively reduced, so that the Ru-RE2O3 catalyst with a core-shell structure is finally obtained. Compared with existing catalysts, the catalyst of the application forms a heterojunction between ruthenium and rare earth oxides and is uniformly loaded on the surface of the carbon sphere, the utilization rate of active sites is high, and the catalyst exhibits excellent water electrolysis catalytic activity, good mass transfer efficiency and stable cycle performance.

Description

Technical Field

[0001] This invention relates to an electrocatalytic material, particularly to a Ru-RE2O3 catalyst, and also to a method for preparing the catalyst and its application. Background Technology

[0002] Electrolysis of water to produce hydrogen is a mainstream technology for green hydrogen production. Due to its wide availability of raw materials and clean, pollution-free products, it is a key path to achieve large-scale green development of hydrogen energy.

[0003] Ruthenium-based catalysts, as ideal alternatives to platinum-based catalysts, still face significant bottlenecks: ruthenium nanoparticles have high surface energy, making them prone to sintering and agglomeration during reactions, leading to a reduction in active sites and decreased catalytic performance; furthermore, their limited electronic structure tunability and insufficient mass transfer efficiency restrict industrial applications. Rare earth oxides, as promoters, can regulate the electronic structure and dispersion of active components, and their combination with ruthenium-based catalysts can optimize the electronic states of ruthenium active sites, inhibit sintering, and improve stability. However, existing composite catalysts still have shortcomings: rare earth oxides are prone to agglomeration, resulting in insufficient contact with ruthenium active sites; and ruthenium-based catalysts and rare earth oxides are difficult to uniformly disperse on HCS. Existing technologies mostly employ support-based modification to inhibit ruthenium particle agglomeration, such as the ruthenium-based rare earth composite catalyst and its preparation method and application disclosed in CN 120575242 A, and the rare earth element-doped Ru-based catalyst and its preparation method and application disclosed in CN 119194496 A. However, these schemes rely on the functional groups of the support to improve catalyst stability.

[0004] Therefore, developing a composite catalyst that enhances catalytic activity, mass transfer efficiency, and stability without requiring special support is of great significance for overcoming existing shortcomings and for industrialization. Summary of the Invention

[0005] Purpose of the invention: The purpose of this invention is to provide a catalyst that improves catalytic activity; this invention also provides a method for preparing the catalyst and its application.

[0006] Technical solution: The catalyst of the present invention includes a rare earth metal oxide RE2O3 shell and Ru inside.

[0007] In the catalyst of this invention, rare earth metals serve as a protective layer for ruthenium (Ru), surrounding the Ru and making full contact with it to form a stable heterojunction structure, which significantly improves the intrinsic activity and stability of the catalyst.

[0008] Preferably, in order to improve catalyst dispersibility, the catalyst is supported on a mesoporous carbon support.

[0009] Preferably, the rare earth metal oxide is at least one of the oxides of gadolinium, lanthanum, praseodymium, neodymium, samarium, europium, erbium, and thulium, and the carbon support is hollow mesoporous carbon.

[0010] Preferably, the catalyst particle size is 1~5 nm.

[0011] The aforementioned method for preparing the catalyst includes the following steps:

[0012] (1) Mix ruthenium salt, rare earth metal salt and carbon support in a liquid medium to disperse the ruthenium salt and rare earth metal salt on the carbon support, and then remove the liquid medium;

[0013] (2) Under the protection of inert gas, the product obtained in step (1) is subjected to a first calcination until the rare earth metal salt and ruthenium salt are converted into the corresponding oxides;

[0014] (3) Under a reducing gas and an inert gas atmosphere, the product obtained in step (2) is subjected to a second calcination until ruthenium oxide is reduced to ruthenium to obtain the catalyst.

[0015] In step (1), mixing in the liquid medium is mainly to improve the dispersion uniformity. The liquid medium can be an organic solvent or water. In order to facilitate the removal of the liquid medium, preferably, the liquid medium is a volatile organic solvent, and the organic solvent is at least one of methanol, ethanol, acetone, isopropanol, dichloromethane, and chloroform.

[0016] Preferably, in step (1), the molar ratio of ruthenium salt to rare earth metal salt is 1:0.15-0.52, and the mass ratio of ruthenium salt to carbon support is 1:0.5-2. The ruthenium salt is ruthenium trichloride, ruthenium acetylacetonate, or ruthenium acetate, and the rare earth metal salt is rare earth metal acetylacetonate, rare earth metal chloride, or rare earth metal nitrate. Insufficient addition of rare earth metals and carbon support will not adequately reduce the charge distribution regulation effect, while excessive addition will affect performance due to their lack of catalytic activity. More preferably, the molar ratio of ruthenium salt to rare earth metal salt is 1:0.18-0.3, and the mass ratio of ruthenium salt to carbon support is 1:0.8-1.2.

[0017] In step (1), there are no special restrictions on the carbon support, but mesoporous carbon is preferred, and hollow mesoporous carbon prepared using tetrapropoxysilane as a template agent is most preferred. The synthesis method of hollow mesoporous carbon is as follows:

[0018] Tetrapropoxysilane and ammonia were dissolved in ethanol to form a colloidal suspension. Resorcinol and formaldehyde were then added to react the product. The product was washed with alcohol and dried. It was then carbonized under inert gas protection and etched with a strong alkali solution to remove SiO2. The product was washed with water and alcohol until neutral and then dried.

[0019] Preferably, the molar ratio of tetrapropoxysilane to resorcinol is 1:0.2-0.4. After adding resorcinol, the reaction time is 18-36 hours, the drying temperature is 50-80℃, the drying time is 12-36 hours, the carbonization temperature is 600-900℃, and the carbonization time is 3-6 hours. The strong alkaline solution is a potassium hydroxide solution or a sodium hydroxide solution with a concentration of 0.5-2 mol / L. The etching removal of SiO2 lasts for 18-36 hours.

[0020] Preferably, in order to improve the uniformity of dispersion, the liquid phase medium is removed by freeze drying in step (1). The freeze drying temperature is -40 to -60°C, the vacuum degree is 5 to 20 kPa, and the time is 24 to 96 hours.

[0021] Preferably, the ruthenium salt and rare earth metal salt are acetylacetonate, and the liquid medium is acetone.

[0022] Preferably, the first calcination temperature is 350–550°C, and the time is 6–10 hours.

[0023] Preferably, in step (3), the reducing gas is hydrogen, the volume fraction of the reducing gas is 5% to 11%, the second calcination temperature is 150 to 200°C, and the time is 1 to 3 hours.

[0024] Preferably, in steps (2) and (3), the inert gas is nitrogen or argon. In step (2), the purpose of using an inert atmosphere is to protect the carrier.

[0025] Preferably, step (2) further includes acid leaching of the rare earth metal oxides and ruthenium oxide. The acid solution used for acid leaching is sulfuric acid or hydrochloric acid, with a hydrogen ion concentration of 0.05–0.2 mol / L, a temperature of 40–60°C, and a duration of 2–6 hours. The acid treatment is used to clean and activate the carbon support, and also acts as an etchant to remove part of the rare earth metal oxides from the outer shell, promoting the reduction of ruthenium oxide and further improving the catalytic performance of the catalyst.

[0026] The aforementioned catalyst is used in the alkaline hydrogen evolution half-reaction of water electrolysis to produce hydrogen.

[0027] Beneficial Effects: Compared with the prior art, the present invention has the following significant advantages: 1. The present invention introduces rare earth metals to enhance the intrinsic activity of the active components. The rare earth metals act as a shell surrounding ruthenium, optimizing the catalyst crystal structure, strengthening the interfacial bonding between ruthenium-based materials, rare earth oxides, and carbon sphere supports, promoting electron transfer, improving catalytic stability, and reducing support requirements; 2. The support used in this scheme has a regular mesoporous structure and a large specific surface area, which can provide sufficient and uniform loading sites for ruthenium-based materials and rare earth oxides, significantly improving the dispersibility of active components; 3. Freeze-drying is used to uniformly disperse ruthenium salts and rare earth metal salts, avoiding agglomeration of active components and improving the utilization rate of active sites; 4. The process of this scheme is simple and controllable, and can be mass-produced, with significant industrial application value and promotion prospects. Attached Figure Description

[0028] Figure 1 Characterization images of the hollow mesoporous carbon spheres prepared in Example 1: (a) Transmission electron microscope (TEM) image and corresponding particle size distribution diagram; (b) Nitrogen adsorption-desorption isotherm and corresponding BJH pore size distribution curve.

[0029] Figure 2 TEM images of Ru-RE2O3 / HCS prepared in Example 1 at different magnifications;

[0030] Figure 3 Aberration-corrected high-angle annular dark-field images and corresponding particle size distributions of Ru-RE2O3 / HCS prepared in Example 1 at different magnifications;

[0031] Figure 4 X-ray diffraction (XRD) pattern of Ru-RE2O3 / HCS prepared in Example 1;

[0032] Figure 5 Fourier transform X-ray extended fine absorption spectrum of Ru-RE2O3 / HCS prepared in Example 1;

[0033] Figure 6 The HER polarization curve of Ru-RE2O3 / HCS prepared in Example 1 in nitrogen-saturated 1 mol / L KOH;

[0034] Figure 7 Chronopotential curve of Ru-RE2O3 / HCS prepared in Example 1 in nitrogen-saturated 1 mol / L KOH. Detailed Implementation

[0035] The technical solution of the present invention will be further described in detail below through specific embodiments. However, it should be noted that the following embodiments are only used to describe the content of the invention and do not constitute a limitation on the scope of protection of the present invention.

[0036] Example 1: Carrier Synthesis: 3.5 mL of tetrapropoxysilane was mixed with 70 mL of ethanol, 10 mL of water, and 3.5 mL of ammonia to form a solution. Simultaneously, 0.4 g of resorcinol was mixed with 2 mL of ethanol and 0.56 mL of formaldehyde to form a solution. The mixture was stirred for 24 hours to allow for complete reaction. After washing with alcohol, the mixture was dried at 60 °C for 24 hours. Then, it was carbonized at 700 °C for 5 hours under an argon atmosphere. Finally, it was etched with 1.0 mol / L sodium hydroxide for 24 hours. After washing with water and alcohol, the mixture was dried at 60 °C for 24 hours to obtain the hollow mesoporous carbon sphere carrier HCS.

[0037] Catalyst preparation: 35 mg of carbon spheres, 35 mg of ruthenium acetylacetone, 10 mg of gadolinium acetylacetone (molecular weight 454.57) were ultrasonically mixed with 3.5 mL of acetone for 20 minutes until homogeneous, and then freeze-dried to obtain a metal salt precursor. The precursor was calcined at 450 °C for 8 hours under an argon atmosphere, then immersed in 0.05 mol / L sulfuric acid, heated to 50 °C, stirred for 4 hours, washed with water until neutral, and dried at 60 °C for 24 hours. The catalyst supported on hollow mesoporous carbon spheres was calcined at 180 °C for 2 hours in an argon-hydrogen mixture containing 10% hydrogen by volume to obtain Ru-RE2O3 / HCS.

[0038] Comparative Example 1: Based on Example 1, without adding rare earth source gadolinium, and with other conditions unchanged, the resulting product is denoted as Ru / HCS.

[0039] Performance testing (1) The hollow mesoporous carbon spheres prepared in Example 1 were physically characterized using a transmission electron microscope (TEM) and a fully automated surface area and porosity analyzer (BET). The results are as follows: Figure 1 As shown. By Figure 1 Part a shows that the synthesized hollow mesoporous carbon spheres are uniform in size, with a diameter of approximately 0.47 micrometers. Part b shows that the carbon spheres have a mesoporous structure, providing abundant metal adsorption sites.

[0040] (2) The Ru-RE2O3 / HCS catalyst prepared in Example 1 was physically characterized by transmission electron microscopy (TEM), and the results are as follows: Figure 2 As shown. By Figure 2 It can be seen that there are abundant and uniform Ru-RE2O3 heterojunction particles on the HCS surface.

[0041] (3) The Ru-RE2O3 / HCS catalyst prepared in Example 1 was further characterized using aberration-corrected transmission electron microscopy, and the results are as follows: Figure 3 As shown. By Figure 3 As can be seen from part a, the Ru-RE2O3 heterojunction particles are uniformly loaded in the carbon spheres, with an average particle size of 3.06 nm; Figure 3In part b, magnifying a single particle reveals that the middle part of the particle is Ru, surrounded by a Gd2O3 shell, with Ru and Gd2O3 forming a heterojunction structure.

[0042] (4) X-ray diffraction tests were performed on the Ru-RE2O3 / HCS prepared in Example 1 to obtain the XRD pattern, as shown below. Figure 4 As shown. By Figure 4 It can be seen that the diffraction peak positions of Ru-RE2O3 / HCS completely coincide with those of the Ru elemental standard card (PDF#70-0274), indicating the successful formation of the Ru cluster. Gd2O3 does not show diffraction peaks due to its low content.

[0043] (5) Synchrotron radiation tests were performed on the Ru-RE2O3 / HCS prepared in Example 1 to obtain a Fourier transform X-ray extended fine absorption spectrum, as shown in the figure. Figure 5 As shown. By Figure 5 As can be seen, compared with the Gd2O3 standard sample, the test spectrum of Ru-RE2O3 / HCS has characteristic peaks of Gd-O and Gd-Gd coordination bonds, proving that Gd2O3 exists in the catalyst sample prepared in Example 1.

[0044] (6) Commercial Pt / C (Johnson Matthey, USA) was used as a reference catalyst. The hydrogen evolution (HER) polarization curves of Ru-RE2O3 / HCS prepared in Example 1, the comparative example, and commercial Pt / C were tested in 1 mol / L KOH saturated with nitrogen. The tests were performed on a CHI 760E electrochemical workstation using a three-electrode system. The test voltage range was -0.4 V to 0 V, and the scan rate was 5 mV / s. All measured potentials were converted to reversible hydrogen electrodes.

[0045] Depend on Figure 6 It can be seen that the Ru-RE2O3 / HCS catalyst prepared in Example 1 operates at a current density of 10 mA cm⁻¹. -2 The overpotential was only 10 mV, which is superior to that of commercial Pt / C (29 mV) and the comparative catalyst (20 mV). Therefore, the Ru-RE2O3 / HCS catalyst prepared in Example 1 exhibits superior HER activity in alkaline electrolyte compared to commercial Pt / C. This is mainly attributed to the introduction of rare earth element Gd, which forms a Ru-Gd2O3 core-shell heterojunction structure with Ru, significantly optimizing the electronic structure of Ru and improving its catalytic performance.

[0046] (7) Chorothermal potentiometry was used to test the Ru-RE2O3 / HCS prepared in Example 1, the comparative Ru / HCS, and commercial Pt / C in nitrogen-saturated 1 mol / L KOH. Figure 7It can be seen that the Ru-RE2O3 / HCS catalyst prepared in Example 1 can maintain stable operation for 140 hours with only slight degradation, which is more stable than commercial Pt / C and Ru / HCS in Comparative Example 1.

[0047] The difference between Example 2 and Example 1 is that 0.4g of resorcinol is replaced with 0.27g of resorcinol, and the rest is the same as in Example 1.

[0048] The difference between Example 3 and Example 1 is that 0.4g of resorcinol is replaced with 0.53g of resorcinol, and the rest is the same as in Example 1.

[0049] The difference between Example 4 and Example 1 is that the high-temperature carbonization at 700°C for 5 hours in an argon atmosphere is replaced with high-temperature carbonization at 600°C for 6 hours in an argon atmosphere. The rest of the content is the same as Example 1.

[0050] The difference between Example 5 and Example 1 is that the high-temperature carbonization at 700°C for 5 hours in an argon atmosphere is replaced with high-temperature carbonization at 900°C for 3 hours in an argon atmosphere. The rest of the content is the same as Example 1.

[0051] The difference between Example 6 and Example 1 is that 1.0 mol / L sodium hydroxide is replaced with 1.0 mol / L potassium hydroxide, and the rest is the same as Example 1.

[0052] The difference between Example 7 and Example 1 is that the etching time of 1.0 mol / L sodium hydroxide for 24 hours is replaced by etching time of 2.0 mol / L sodium hydroxide for 18 hours. The rest of the process is the same as in Example 1.

[0053] The difference between Example 8 and Example 1 is that the etching time of 24 hours with 1.0 mol / L sodium hydroxide is replaced with etching time of 36 hours with 0.5 mol / L sodium hydroxide. The rest of the process is the same as in Example 1.

[0054] The difference between Example 9 and Example 1 is that ruthenium acetylacetone is replaced with ruthenium chloride, while the rest is the same as in Example 1.

[0055] The difference between Example 10 and Example 1 is that ruthenium acetylacetone is replaced with ruthenium acetate, while the rest is the same as in Example 1.

[0056] The difference between Example 11 and Example 1 is that gadolinium acetylacetonate is replaced with lanthanum acetylacetonate, and the corresponding product is denoted as Ru-La2O3 / HCS. The rest of the contents are the same as in Example 1.

[0057] The difference between Example 12 and Example 1 is that gadolinium acetylacetonate is replaced with praseodymium acetylacetonate, and the corresponding product is denoted as Ru-Pr2O3 / HCS. The rest of the contents are the same as in Example 1.

[0058] The difference between Example 13 and Example 1 is that gadolinium acetylacetonate is replaced with neodymium acetylacetonate, and the corresponding product is denoted as Ru-Nd2O3 / HCS. The rest is the same as in Example 1.

[0059] Example 14 differs from Example 1 in that gadolinium acetylacetonate is replaced with samarium acetylacetonate, and the corresponding product is denoted as Ru-Sm2O3 / HCS. The rest of the contents are the same as in Example 1.

[0060] The difference between Example 15 and Example 1 is that gadolinium acetylacetonate is replaced with europium acetylacetonate, and the corresponding product is denoted as Ru-Eu2O3 / HCS. The rest is the same as in Example 1.

[0061] The difference between Example 16 and Example 1 is that gadolinium acetylacetonate is replaced with erbium acetylacetonate, and the corresponding product is denoted as Ru-Er2O3 / HCS. The rest is the same as in Example 1.

[0062] The difference between Example 17 and Example 1 is that gadolinium acetylacetonate is replaced with thulium acetylacetonate, and the corresponding product is denoted as Ru-Tm2O3 / HCS. The rest is the same as in Example 1.

[0063] The difference between Example 18 and Example 1 is that gadolinium acetylacetonate is replaced with gadolinium chloride, while the rest is the same as Example 1.

[0064] The difference between Example 19 and Example 1 is that gadolinium acetylacetonate is replaced with gadolinium nitrate, while the rest is the same as Example 1.

[0065] The difference between Example 20 and Example 1 is that acetone is replaced with isopropanol, and the rest is the same as Example 1.

[0066] Example 21 differs from Example 1 in that acetone is replaced with anhydrous ethanol, while the rest is the same as Example 1.

[0067] Example 22 differs from Example 1 in that 10 mg of gadolinium acetylacetonate is replaced with 8 mg of gadolinium acetylacetonate; otherwise, the contents are the same as in Example 1.

[0068] Example 23 differs from Example 1 in that 10 mg of gadolinium acetylacetonate is replaced with 20 mg of gadolinium acetylacetonate, while the rest is the same as Example 1.

[0069] Example 24 differs from Example 1 in that 35 mg of carbon spheres is replaced with 17.5 mg of carbon spheres; otherwise, it is identical to Example 1. The overpotential of the sample in this example is 12 mV, slightly higher than that in Example 1, possibly due to the reduced carrier content and decreased uniformity of the active ingredient.

[0070] Example 25 differs from Example 1 in that 35 mg of carbon spheres is replaced with 70 mg of carbon spheres; otherwise, the contents are the same as in Example 1. The overpotential of the sample in this example is 13 mV, slightly higher than in Example 1, possibly due to excessive carrier content leading to decreased uniformity of the active ingredient.

[0071] The difference between Example 26 and Example 1 is that the high-temperature calcination at 450°C for 8 hours in an argon atmosphere is replaced with high-temperature calcination at 350°C for 10 hours in an argon atmosphere. The rest of the content is the same as Example 1.

[0072] The difference between Example 27 and Example 1 is that the high-temperature calcination at 450°C for 8 hours in an argon atmosphere is replaced with high-temperature calcination at 550°C for 6 hours in an argon atmosphere. The rest of the content is the same as Example 1.

[0073] The difference between Example 28 and Example 1 is that the etching with 0.05 mol / L sulfuric acid for 4 hours is replaced with etching with 0.1 mol / L hydrochloric acid for 4 hours. The rest of the content is the same as Example 1.

[0074] Example 29 differs from Example 1 in that the etching time is changed from 4 hours of 0.05 mol / L sulfuric acid to 2 hours of 0.1 mol / L sulfuric acid. The rest of the process is the same as Example 1. The overpotential of the product in this example is 13 mV, slightly higher than that in Example 1. This may be due to the shorter acid treatment time, a slightly thicker outer shell of the non-catalytic rare earth oxides, and the fact that the rare earth metals themselves lack catalytic activity, thus affecting the overall catalytic activity.

[0075] The difference between Example 30 and Example 1 is that the etching time of 4 hours with 0.05 mol / L sulfuric acid was replaced with 7 hours with 0.025 mol / L sulfuric acid. All other aspects are the same as in Example 1. The overpotential of the sample in this example was 13 mV, and the chronopotential curve showed greater fluctuations than in Example 1. This may be because the rare earth outer shell was excessively removed, affecting stability.

[0076] The difference between Example 31 and Example 1 is that the calcination at 180°C for 2 hours in an argon-hydrogen mixture with a hydrogen content of 10% is replaced with calcination at 180°C for 2 hours in an argon-hydrogen mixture with a hydrogen content of 5%. The rest of the contents are the same as in Example 1.

[0077] The difference between Example 32 and Example 1 is that the calcination at 180°C for 2 hours in an argon-hydrogen mixture with 10% hydrogen content is replaced with calcination at 150°C for 3 hours in an argon-hydrogen mixture with 10% hydrogen content. The rest of the content is the same as Example 1.

[0078] The difference between Example 33 and Example 1 is that the calcination at 180°C for 2 hours in an argon-hydrogen mixture with 10% hydrogen content is replaced with calcination at 200°C for 1 hour in an argon-hydrogen mixture with 10% hydrogen content. The rest of the content is the same as Example 1.

[0079] Example 34 differs from Example 1 in that the 0.05 mol / L sulfuric acid is replaced with deionized water; the remaining steps are the same as in Example 1. The overpotential of the sample in this example is 16 mV, which is higher than in Example 1. This may be because the acid treatment was omitted, the carbon support was less clean, or the rare earth oxide shell was slightly thicker.

[0080] In summary, the catalyst of this invention features a simple and controllable preparation process, enabling large-scale production. This method effectively solves the problems of active component agglomeration, uneven loading, weak interfacial bonding, and insufficient catalytic performance in traditional preparation methods. In the obtained catalyst, ruthenium and rare earth oxides are uniformly loaded on the surface of hollow mesoporous carbon spheres, exhibiting high utilization of active sites and excellent electron transfer efficiency. This effectively reduces the energy consumption for hydrogen production via water electrolysis, demonstrating significant industrial application value and broad market prospects.

Claims

1. A catalyst, characterized in that, It includes a rare earth metal oxide (RE2O3) shell and an inner Ru.

2. The catalyst according to claim 1, characterized in that, The catalyst is supported on a mesoporous carbon support.

3. The catalyst according to claim 2, characterized in that, The carbon support is hollow mesoporous carbon, and the rare earth metal oxide is at least one of gadolinium oxide, lanthanum oxide, praseodymium oxide, neodymium oxide, samarium oxide, europium oxide, erbium oxide, and thulium oxide.

4. The catalyst according to claim 2, characterized in that, The catalyst has a particle size of 1~5nm.

5. The method for preparing the catalyst according to any one of claims 1 to 2, characterized in that, Includes the following steps: (1) Mix ruthenium salt, rare earth metal salt and carbon support in a liquid medium to disperse the ruthenium salt and rare earth metal salt on the carbon support, and then remove the liquid medium; (2) Under the protection of inert gas, the product obtained in step (1) is subjected to a first calcination until the rare earth metal salt and ruthenium salt are converted into the corresponding oxides; (3) Under a reducing gas and a protective inert atmosphere, the product obtained in step (2) is subjected to a second calcination until ruthenium oxide is reduced to ruthenium to obtain the catalyst.

6. The preparation method according to claim 5, characterized in that, In step (1), the molar ratio of ruthenium salt to rare earth metal salt is 1:0.15 to 0.52, the mass ratio of ruthenium salt to carbon support is 1:0.5 to 2, and the liquid medium is a volatile organic solvent.

7. The preparation method according to claim 5, characterized in that, In step (2), the first calcination temperature is 350~550℃ and the duration is 6~10 hours.

8. The preparation method according to claim 5, characterized in that, In step (2), the rare earth metal oxide and ruthenium oxide are further subjected to acid leaching treatment. The acid used for acid leaching treatment is sulfuric acid and / or hydrochloric acid, the hydrogen ion concentration is 0.05 to 0.2 mol / L, the temperature is 40 to 60°C, and the duration is 2 to 6 hours.

9. The preparation method according to claim 5, characterized in that, In step (3), the second calcination temperature is 150~200℃, the duration is 1~3 hours, the reducing gas is hydrogen, and the volume fraction of the reducing gas is 5~11%.

10. The preparation method according to claim 5, characterized in that, The ruthenium salt and rare earth metal salt are acetylacetonate salts, and the liquid medium is acetone.

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