Conducting layer coated ruthenium-doped beta-manganese dioxide catalyst as well as preparation method and application thereof

Abstract

The invention discloses a conductive layer coated ruthenium-doped beta-manganese dioxide catalyst and a preparation method and application thereof.The preparation method comprises the following steps that a manganese source, ruthenium trichloride trihydrate, an oxidizing agent and water are mixed, an obtained precursor solution is subjected to microwave synthesis, and the conductive layer coated ruthenium-doped beta-manganese dioxide catalyst is obtained. The obtained ruthenium-doped beta-manganese dioxide composite material, hydrochloric acid A and aniline are added into water, then hydrochloric acid B and ammonium persulfate are added, the obtained polyaniline-coated ruthenium-doped beta-manganese dioxide composite material is subjected to calcination treatment, and the conductive layer-coated ruthenium-doped beta-manganese dioxide catalyst is obtained. The conductive layer coated ruthenium-doped beta-manganese dioxide catalyst prepared by the invention has excellent catalytic activity and catalytic stability, and solves the problem of insufficient stability caused by high catalytic potential and catalyst dissolution in the test process of the anode catalyst of the proton exchange membrane electrolytic cell.

Description

Technical Field

[0001] This invention relates to the field of ruthenium-based catalyst technology, specifically to a ruthenium-doped β-manganese dioxide catalyst with a conductive layer coated thereon, its preparation method, and its application. Background Technology

[0002] With the continued growth in global demand for renewable energy, hydrogen, as a high-energy-density and environmentally friendly carbon-neutral energy carrier, plays a crucial role in the future energy system. To achieve green hydrogen production, alkaline electrolyzers and proton exchange membrane (PEM) electrolyzers are currently the main technologies used. Among them, PEM electrolyzers have significant advantages over traditional alkaline electrolyzers, including high energy density, high energy conversion efficiency, high hydrogen purity, and rapid start-up and shutdown. However, the oxygen evolution reaction at the anode in PEM electrolyzers is slow due to the four-electron transfer process in the oxygen intermediate, requiring a high catalytic potential. Simultaneously, the high current density and characteristics of the PEM in commercial applications place the anode in a harsh environment of strong oxidizing and high acidity, resulting in a lack of stable and efficient catalysts under acidic conditions. This has become a key bottleneck restricting its large-scale industrial application.

[0003] Currently, iridium-based and ruthenium-based catalysts are commonly used catalysts for the anodes of proton exchange membrane electrolyzers (PEMECs). While iridium-based electrocatalysts exhibit excellent catalytic activity and stability, making them suitable for industrial anodes, their scarcity and high cost, coupled with the high loading requirements per unit area in PEMECs, significantly increase the overall cost and severely limit the large-scale adoption of PEMECs. Ruthenium-based catalysts, although exhibiting high activity, are prone to oxidation and dissolution during operation and have poor stability, similarly failing to meet the demands of large-scale applications. Furthermore, existing catalysts generally suffer from poor dispersion of active sites and a tendency to aggregate, resulting in low utilization of reactive sites and further increasing the amount of precious metals required.

[0004] In summary, there is an urgent need to develop a proton exchange membrane electrolyzer anode catalyst that combines high activity, high stability, low cost, and high utilization of active sites. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a ruthenium-doped β-manganese dioxide catalyst coated with a conductive layer, its preparation method, and its application.

[0006] This invention is achieved through the following technical solution:

[0007] The first aspect of this invention provides a method for preparing a ruthenium-doped β-manganese dioxide catalyst coated with a conductive layer, comprising the following steps:

[0008] (1) A precursor solution is obtained by mixing a manganese source, a ruthenium source, an oxidant and water; wherein the molar ratio of the manganese source and the oxidant is (1.5-2.35):1; and the ruthenium source is ruthenium trichloride trihydrate.

[0009] (2) The precursor solution obtained in step (1) was placed in a microwave reactor for microwave synthesis to obtain ruthenium-doped β-manganese dioxide composite material;

[0010] (3) The ruthenium-doped β-manganese dioxide composite material obtained in step (2), hydrochloric acid A and aniline were added to water under ice-water bath conditions, and then hydrochloric acid B and ammonium persulfate were added and stirred to obtain polyaniline-coated ruthenium-doped β-manganese dioxide composite material.

[0011] (4) The ruthenium-doped β-manganese dioxide composite material obtained in step (3) is calcined at 300-400℃ to obtain the ruthenium-doped β-manganese dioxide catalyst coated with the conductive layer.

[0012] This invention uses manganese dioxide as a base and dops it with the active element ruthenium, so that ruthenium is uniformly dispersed in manganese dioxide. This solves the problem of uneven dispersion of catalytic sites, improves the utilization rate of ruthenium at active sites, reduces the amount of precious metal ruthenium used, lowers the price of catalyst, and solves the problem of high cost in large-scale catalyst preparation.

[0013] The ruthenium-doped β-manganese dioxide catalyst with a conductive layer prepared by this invention has excellent catalytic activity and catalytic stability, solving the problems of high catalytic potential and insufficient stability caused by catalyst dissolution in the anode catalyst of proton exchange membrane electrolyzers during testing.

[0014] Further, in step (1), the manganese source is manganese sulfate and / or manganese chloride, which can be manganese sulfate monohydrate; the oxidant is potassium permanganate and / or ammonium persulfate.

[0015] Further, in step (1), the molar ratio of the manganese source and the ruthenium source is (1-2):0.5.

[0016] Furthermore, in step (1), the ratio of manganese source to water is 2 mmol: 20-40 mL.

[0017] When the molar ratio of manganese source to oxidant is too low, such as 1:2, α-manganese dioxide is ultimately synthesized; when the molar ratio is too high, such as 5:1, δ-manganese dioxide is ultimately synthesized. Among all crystalline forms of manganese dioxide, β-manganese dioxide with a 1×1 tunnel structure has the smallest tunnel structure, the most compact structure, and generates the greatest lattice stress when doped with a foreign metal. In this invention, the lattice stress generated when the foreign metal ruthenium is incorporated promotes ruthenium segregation during calcination.

[0018] Further, in step (1), the manganese source is added to water, then an oxidant is added and stirred for 10-20 min, followed by sonication for 3-10 min, and then a ruthenium source is added and stirred for 10-20 min to obtain a precursor solution.

[0019] The stirring time after adding the oxidant should not be less than 10 minutes, otherwise manganese dioxide will be difficult to nucleate; the stirring time after adding the ruthenium source should not be less than 10 minutes, otherwise ruthenium trichloride trihydrate will be difficult to disperse.

[0020] Furthermore, in step (2), the stirring rate of the microwave synthesis is 300-500 rpm and the microwave power is 300-500 W.

[0021] Further, in step (2), the conditions for microwave synthesis are: heating from 20-40℃ to 110-130℃ within 5-15 minutes and holding for 2-5 minutes, and then heating to 160-180℃ within 3-8 minutes and holding for 20-40 minutes.

[0022] Further, in step (2), after the microwave synthesis is completed, the solution is centrifuged and the precipitate is dried to obtain ruthenium-doped β-manganese dioxide composite material.

[0023] Specifically, after the microwave synthesis is completed, the solution is cooled and centrifuged with deionized water and ethanol. The precipitate is then dried in an oven to obtain a ruthenium-doped β-manganese dioxide composite material.

[0024] Furthermore, in step (3), the ratio of ruthenium-doped β-manganese dioxide composite material to aniline is 0.1-5 mg: 0.0015 mL. If the amount of ruthenium-doped β-manganese dioxide composite material is too low, subsequent material collection will be difficult.

[0025] Further, in step (3), the volume ratio of aniline to hydrochloric acid A is (0.03-0.15):5.

[0026] Further, in step (3), the concentration of hydrochloric acid A is 0.3-0.7M.

[0027] Further, in step (3), the mass ratio of the ruthenium-doped β-manganese dioxide composite material to ammonium persulfate is (0.1-5):2.

[0028] Further, in step (3), the ratio of ammonium persulfate to hydrochloric acid B is 30-300 mg: 5 mL.

[0029] Furthermore, in step (3), the concentration of hydrochloric acid B is 0.3-0.7M.

[0030] Furthermore, in step (3), the stirring time after adding hydrochloric acid B and ammonium persulfate is 5-8 hours.

[0031] The stirring time after adding hydrochloric acid B and ammonium persulfate should not exceed 8 hours, otherwise the ruthenium-doped β-manganese dioxide composite material will be gradually dissolved.

[0032] Specifically, in step (3), the ruthenium-doped β-manganese dioxide composite material obtained in step (2) is added to water and stirred under ice-water bath conditions. Hydrochloric acid and aniline are added to allow the aniline monomer to attach to the ruthenium-doped β-manganese dioxide composite material. Aniline is polymerized by adding hydrochloric acid and ammonium persulfate to obtain polyaniline-coated ruthenium-doped β-manganese dioxide composite material.

[0033] Specifically, after adding hydrochloric acid and ammonium persulfate to polymerize aniline, the process also includes centrifuging the resulting solution and drying the precipitate.

[0034] Further, in step (4), the ruthenium-doped β-manganese dioxide composite material obtained in step (3) is heated to 300-400℃ at a heating rate of 4-8℃ / min and calcined for 3-4h to obtain the ruthenium-doped β-manganese dioxide catalyst coated with the conductive layer.

[0035] Specifically, in step (4), the ruthenium-doped β-manganese dioxide composite material obtained in step (3) is placed in a tube furnace and heated to 300-400℃ at a heating rate of 4-8℃ / min for calcination treatment for 3-4 hours to obtain the ruthenium-doped β-manganese dioxide catalyst coated with the conductive layer.

[0036] The second aspect of the present invention provides a ruthenium-doped β-manganese dioxide catalyst with a conductive layer prepared by the preparation method described in the first aspect.

[0037] The third aspect of the present invention provides the application of the ruthenium-doped β-manganese dioxide catalyst with the conductive layer described in the second aspect in the electrolysis of water to produce hydrogen.

[0038] Furthermore, the ruthenium-doped β-manganese dioxide catalyst coated with the conductive layer serves as the anode catalyst for the proton exchange membrane electrolyzer.

[0039] Furthermore, the ruthenium-doped β-manganese dioxide catalyst coated on the conductive layer has a loading of 0.1-15 mg·cm³ on the electrode. -2 Preferably 1-12 mg·cm -2 .

[0040] The beneficial effects of this invention are:

[0041] 1. This invention uses manganese dioxide as a base and dops it with the active element ruthenium, so that ruthenium is uniformly dispersed in manganese dioxide. This solves the problem of uneven dispersion of catalytic sites, improves the utilization rate of ruthenium at active sites, and at the same time reduces the amount of precious metal ruthenium used, thereby reducing the price of the catalyst and making it more economical. It also solves the problem of high cost of large-scale catalyst preparation.

[0042] 2. The present invention uses a conductive layer to coat a ruthenium-doped β-manganese dioxide composite material. The resulting conductive layer-coated ruthenium-doped β-manganese dioxide catalyst improves electron transport efficiency, reduces impedance, enhances catalytic activity, lowers catalytic potential, and limits the dissolution of active elements during the test process, significantly improving stability. This solves the problems of high catalytic potential and insufficient stability caused by catalyst dissolution in proton exchange membrane electrolyzer anode catalysts during the test process. Attached Figure Description

[0043] Figure 1 This is a schematic diagram of the preparation process of the ruthenium-doped β-manganese dioxide catalyst coated with the conductive layer in Example 1.

[0044] Figure 2 The images show scanning electron microscope (SEM) and X-ray diffraction (XRD) images of the ruthenium-doped β-manganese dioxide catalyst coated with a conductive layer prepared in Example 1; where a) is the SEM image and b) is the XRD image.

[0045] Figure 3 The images show transmission electron microscopy (TEM) images of the ruthenium-doped β-manganese dioxide composite material and the ruthenium-doped β-manganese dioxide catalyst coated with a conductive layer in Example 1; where a) is the ruthenium-doped β-manganese dioxide composite material and b) is the ruthenium-doped β-manganese dioxide catalyst coated with a conductive layer.

[0046] Figure 4 The images show the in-situ infrared spectra of the ruthenium-doped β-manganese dioxide composite material and the ruthenium-doped β-manganese dioxide catalyst coated with a conductive layer in Example 1; where a) is the ruthenium-doped β-manganese dioxide composite material and b) is the ruthenium-doped β-manganese dioxide catalyst coated with a conductive layer.

[0047] Figure 5 The X-ray absorption fine structure spectra of manganese and ruthenium in the ruthenium-doped β-manganese dioxide composite material in Example 1 are obtained after Fourier transform; wherein, a) is the X-ray absorption fine structure spectrum of manganese after Fourier transform, and b) is the X-ray absorption fine structure spectrum of ruthenium after Fourier transform.

[0048] Figure 6The X-ray absorption fine structure spectra of manganese and ruthenium in the ruthenium-doped β-manganese dioxide catalyst coated with the conductive layer prepared in Example 1 are obtained after Fourier transform; wherein, a) is the X-ray absorption fine structure spectrum of ruthenium after Fourier transform, and b) is the X-ray absorption fine structure spectrum of manganese after Fourier transform.

[0049] Figure 7 The images shown are SEM and TEM images of the ruthenium-doped β-manganese dioxide catalyst with a conductive layer prepared in Example 2; where a) is the SEM image and b) is the TEM image.

[0050] Figure 8 The figures show the catalytic activity and stability test results of the ruthenium-doped β-manganese dioxide catalyst with conductive layer coated in Example 1; where a) is the catalytic activity test result and b) is the stability test result. Detailed Implementation

[0051] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0052] 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.

[0053] The following examples use instruments and equipment conventional in the art. The microwave reactor used in these examples is a multifunctional microwave synthetic extraction instrument, purchased from Shanghai Xinyi Microwave Chemistry Technology Co., Ltd., model UWave-2000, instrument serial number UW2139. Experimental methods in the following examples, unless otherwise specified, are generally performed under standard conditions or as recommended by the manufacturer.

[0054] All raw materials used in the following examples are conventional commercially available products with specifications in the art, unless otherwise stated. In the examples below, ruthenium trichloride trihydrate was purchased from Shanghai Haohong Biomedical Technology Co., Ltd., with a purity of 98%.

[0055] Example 1

[0056] A method for preparing a ruthenium-doped β-manganese dioxide catalyst coated with a conductive layer includes the following steps:

[0057] (1) Take a 100mL round-bottom flask, add 30mL of deionized water, add 0.338g of manganese sulfate monohydrate, stir until colorless and transparent, then add 0.158g of potassium permanganate, stir for 20min, sonicate for 5min, add 0.1307g of ruthenium trichloride trihydrate, stir for 10min to obtain a uniform brown precursor solution. The molar ratio of manganese sulfate monohydrate to potassium permanganate is 2:1.

[0058] (2) The precursor solution obtained in step (1) was placed in a microwave reactor, and ruthenium-doped β-manganese dioxide composite material was synthesized using microwave. The specific conditions for microwave synthesis were: magnetic spindle speed of 400 rpm, microwave power of 400 W, temperature increase from room temperature to 120℃ in 10 min, holding at 120℃ for 3 min, then increasing to 180℃ in 5 min and holding for 30 min. After cooling, the resulting solution was taken out, centrifuged and dried using water and ethanol to obtain the ruthenium-doped β-manganese dioxide composite material.

[0059] (3) After grinding the ruthenium-doped β-manganese dioxide composite material obtained in step (2), 100 mg was poured into a round-bottom flask, 20 mL of deionized water was added, and the mixture was sonicated for 10 min, then stirred in an ice-water bath for 10 min. 5 mL of 0.5 M hydrochloric acid and 0.15 mL of aniline were added, and the mixture was stirred in an ice-water bath for another 10 min. Then, 5 mL of 0.5 M hydrochloric acid and 300 mg of ammonium persulfate were added. After stirring in an ice-water bath for 6 h, the solution was removed, centrifuged with ethanol, and then dried in an oven to obtain the polyaniline-coated ruthenium-doped β-manganese dioxide composite material.

[0060] (4) The polyaniline-coated ruthenium-doped β-manganese dioxide composite material obtained in step (3) is placed in a ceramic boat and placed in a tube furnace. The temperature is raised to 350°C at a heating rate of 5°C / min for 3 hours to obtain the conductive layer-coated ruthenium-doped β-manganese dioxide catalyst.

[0061] Figure 1 This is a schematic diagram of the preparation process of the ruthenium-doped β-manganese dioxide catalyst coated with the conductive layer in Example 1.

[0062] Figure 2 The images show the SEM and XRD patterns of the ruthenium-doped β-manganese dioxide catalyst with a conductive layer prepared in Example 1; where a) is the SEM image and b) is the XRD pattern.

[0063] Figure 3 The images show TEM images of the ruthenium-doped β-manganese dioxide composite material and the ruthenium-doped β-manganese dioxide catalyst coated with a conductive layer in Example 1; where a) is the ruthenium-doped β-manganese dioxide composite material and b) is the ruthenium-doped β-manganese dioxide catalyst coated with a conductive layer.

[0064] Figure 4 The images show the in-situ infrared spectra of the ruthenium-doped β-manganese dioxide composite material and the ruthenium-doped β-manganese dioxide catalyst coated with a conductive layer in Example 1; where a) is the ruthenium-doped β-manganese dioxide composite material and b) is the ruthenium-doped β-manganese dioxide catalyst coated with a conductive layer.

[0065] Figure 5 The X-ray absorption fine structure spectra of manganese and ruthenium in the ruthenium-doped β-manganese dioxide composite material in Example 1 are obtained after Fourier transform; where a) is the X-ray absorption fine structure spectrum of manganese after Fourier transform, and b) is the X-ray absorption fine structure spectrum of ruthenium after Fourier transform. The X-ray absorption fine structure data after Fourier transform show that after ruthenium doping, the manganese oxygen bond shifts to the right, and the ruthenium oxygen bond shifts to the left, indicating an interaction between manganese dioxide and ruthenium.

[0066] Figure 6 The X-ray absorption fine structure (XAS) spectra of manganese and ruthenium in the ruthenium-doped β-manganese dioxide catalyst coated with a conductive layer prepared in Example 1 are shown in Figure 1. Specifically, a) is the XAS fine structure spectrum of ruthenium after Fourier transform, and b) is the XAS fine structure spectrum of manganese after Fourier transform. The XAS fine structure data after Fourier transform show that after the conductive layer is coated with ruthenium doping, the manganese-oxygen bond shifts to the right, the ruthenium-oxygen bond shifts to the right, but the manganese-oxygen-manganese bond shifts to the left. This indicates that ruthenium interacts not only with the manganese-oxygen on the surface but also with the manganese-oxygen-manganese bond within the manganese dioxide, enhancing the stability of the active ruthenium sites. The difference in surface morphology between the conductive layer-coated active sites and the ruthenium-doped β-manganese dioxide composite material also affects stability. In-situ infrared spectroscopy tests show that, compared to the ruthenium-doped β-manganese dioxide composite material, the ruthenium-doped β-manganese dioxide catalyst coated with a conductive layer exhibits higher adsorption density at 1121 cm⁻¹ in the intermediate. -1 Unlike other methods, the conductive layer coating can effectively regulate the catalytic reaction pathway of the catalyst.

[0067] Example 2

[0068] A method for preparing a ruthenium-doped β-manganese dioxide catalyst coated with a conductive layer includes the following steps:

[0069] (1) Take a 100mL round-bottom flask, add 30mL of deionized water, add 0.338g of manganese sulfate, stir until colorless and transparent, then add 0.158g of potassium permanganate, stir for 5min, sonicate for 5min, add 0.1307g of ruthenium trichloride trihydrate, and stir for 10min to obtain a uniform brown precursor solution. The molar ratio of manganese sulfate to potassium permanganate is 2:1.

[0070] (2) The precursor solution obtained in step (1) was placed in a microwave reactor, and ruthenium-doped β-manganese dioxide composite material was synthesized using microwave. The specific conditions for microwave synthesis were: magnetic spindle speed of 400 rpm, microwave power of 400 W, temperature increase from room temperature to 120℃ in 10 min, holding at 120℃ for 3 min, then increasing to 180℃ in 5 min and holding for 30 min. After cooling, the resulting solution was taken out, centrifuged and dried using water and ethanol to obtain the ruthenium-doped β-manganese dioxide composite material.

[0071] (3) After grinding the ruthenium-doped β-manganese dioxide composite material obtained in step (2), 20 mg of the material was poured into a 100 mL volumetric flask, 20 mL of deionized water was added, and the mixture was sonicated for 10 min. Then, it was stirred in an ice-water bath for 10 min. 5 mL of 0.5 M hydrochloric acid and 30 μL of aniline were added, and the mixture was stirred in an ice-water bath for 30 min. Then, 5 mL of 0.5 M hydrochloric acid and 60 mg of ammonium persulfate were added. After stirring in an ice-water bath for 5.5 h, the solution was removed, centrifuged with ethanol, and dried in an oven to obtain the polyaniline-coated ruthenium-doped β-manganese dioxide composite material.

[0072] (4) The polyaniline-coated ruthenium-doped β-manganese dioxide composite material obtained in step (3) is placed in a ceramic boat and placed in a tube furnace. The temperature is raised to 350°C at a heating rate of 5°C / min for 3 hours to obtain the conductive layer-coated ruthenium-doped β-manganese dioxide catalyst.

[0073] Figure 7 The images shown are SEM and TEM images of the ruthenium-doped β-manganese dioxide catalyst with a conductive layer prepared in Example 2; where a) is the SEM image and b) is the TEM image.

[0074] Test Example 1

[0075] 4 mg of the ruthenium-doped β-manganese dioxide catalyst with a conductive layer prepared in Example 1 and 1 mg of Ketjen Black conductive carbon black (KB) were mixed, and 800 μL of ethanol, 200 μL of deionized water, and 50 μL of perfluorosulfonic acid resin solution (Nafion, 5% by mass) were added. The mixture was ultrasonically dispersed for 30 min until a homogeneous slurry was formed. 10 μL of the homogeneous slurry was drop-coated three times onto a platinum-carbon rotating disk electrode with a working diameter of 5 mm. (The loading of the ruthenium-doped β-manganese dioxide catalyst with a conductive layer prepared in Example 1 on the electrode was 0.203 mg·cm³.) -2 It can be used after being naturally dried at room temperature until the surface is uniform and flat, without cracks or agglomeration. It is then assembled onto the rotating rod of the rotating disc electrode manufactured by PINE in the United States at a speed of 1600 rpm.

[0076] Electrochemical tests were performed using a Chenhua electrochemical workstation (CHI760E) at 25℃. The electrolyte was 0.5M H₂SO₄. The counter electrode was a carbon rod, and the reference electrode was a saturated calomel electrode (with saturated KCl as the reference solution). Before the test, nitrogen gas was bubbled into the electrolyte for 30 minutes to saturate the electrolyte with dissolved gases. Linear sweep voltammetry was used to test the reactivity. The initial potential input was 0.956V, the termination potential input was 1.556V (corresponding to RHE of 1.2-1.8V), the waiting time was 2 seconds, and the scan rate was 10 mV / s. -1 Overpotential (η) is the difference between the actual potential and the theoretical value at a specific current density (1.23V vs. RHE). Physically, it represents the portion of the actual operating potential that exceeds the theoretical equilibrium potential. For the oxygen evolution reaction activity of catalysts, a specific current density (10 mA·cm⁻¹) is typically compared. -2 The overpotential of η is used as a standard to measure the activity of different catalysts. The lower the value of η, the higher the intrinsic activity of the catalyst.

[0077] Stability testing was conducted using a three-electrode system. Hydrophobic carbon paper of model YLS-30T was cut into pieces with a working area of ​​1×1 cm. 2 The working electrode has tabs. The above homogeneous slurry is uniformly drop-coated onto the working area with a loading of 1 mg·cm⁻¹. -2 Thoroughly dry the slurry to remove all solvents and avoid affecting stability testing. Use a platinum electrode clamp to hold the pre-drilled tabs on the carbon paper as the working electrode, immersing it in 0.5M H₂SO₄ electrolyte (clamp above the liquid surface, carbon paper below to avoid interference). The counter electrode is a carbon rod, and the reference electrode is a saturated calomel electrode. Stability testing is performed using the chronoamperometry method, providing a constant current of 10mA and a constant current density of 10mA·cm⁻¹. -2 Record the time and voltage curves.

[0078] Test results are as follows Figure 8 As shown, Figure 8 The figures show the catalytic activity and stability test results of the ruthenium-doped β-manganese dioxide catalyst with a conductive layer coated in Example 1; where a) is the catalytic activity test result and b) is the stability test result. In the activity test results, the scanning linear voltammetry tests of the ruthenium-doped β-manganese dioxide catalyst with a conductive layer coated in Example 1 and the RuO2 catalyst show that the RuO2 catalyst exhibits better stability at 10 mA·cm⁻¹. -2 The potential under the current is 1.548V, and the overpotential is 318mV; while the ruthenium-doped β-manganese dioxide catalyst with conductive layer coated in Example 1 has a potential of 1.548V and an overpotential of 318mV; while the ruthenium-doped β-manganese dioxide catalyst with conductive layer coated in Example 1 has a potential of 10mA·cm -2The potential at this point is only 1.394V, and the overpotential is 164mV. In the stability test, the scanning linear voltammetry of the ruthenium-doped β-manganese dioxide catalyst with conductive layer coated in Example 1 and the RuO2 catalyst showed that the RuO2 catalyst was stable in 0.5M H2SO4 for less than 30h, while the ruthenium-doped β-manganese dioxide catalyst with conductive layer coated in Example 1 could be stable in 0.5M H2SO4 for more than 300h.

[0079] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art should understand that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing a ruthenium-doped β-manganese dioxide catalyst coated with a conductive layer, characterized in that, Includes the following steps: (1) A precursor solution is obtained by mixing a manganese source, a ruthenium source, an oxidant and water; wherein the molar ratio of the manganese source and the oxidant is (1.5-2.35):1; and the ruthenium source is ruthenium trichloride trihydrate. (2) The precursor solution obtained in step (1) was placed in a microwave reactor for microwave synthesis to obtain ruthenium-doped β-manganese dioxide composite material; (3) The ruthenium-doped β-manganese dioxide composite material obtained in step (2), hydrochloric acid A and aniline were added to water under ice-water bath conditions, and then hydrochloric acid B and ammonium persulfate were added and stirred to obtain polyaniline-coated ruthenium-doped β-manganese dioxide composite material. (4) The ruthenium-doped β-manganese dioxide composite material obtained in step (3) is calcined at 300-400℃ to obtain the ruthenium-doped β-manganese dioxide catalyst coated with the conductive layer.

2. The preparation method according to claim 1, characterized in that, In step (1), the manganese source is manganese sulfate and / or manganese chloride; the oxidant is potassium permanganate and / or ammonium persulfate.

3. The preparation method according to claim 1, characterized in that, In step (1), the molar ratio of the manganese source and the ruthenium source is (1-2):0.

5.

4. The preparation method according to claim 1, characterized in that, In step (2), the stirring rate of the microwave synthesis is 300-500 rpm and the microwave power is 300-500 W.

5. The preparation method according to claim 1, characterized in that, In step (2), the microwave synthesis conditions are as follows: the temperature is raised from 20-40℃ to 110-130℃ within 5-15 minutes and held for 2-5 minutes, and then raised to 160-180℃ within 3-8 minutes and held for 20-40 minutes.

6. The preparation method according to claim 1, characterized in that, In step (3), the ratio of the amount of ruthenium-doped β-manganese dioxide composite material to aniline is 0.1-5 mg: 0.0015 mL; the mass ratio of the ruthenium-doped β-manganese dioxide composite material to ammonium persulfate is (0.1-5):

2.

7. The preparation method according to claim 1, characterized in that, In step (3), the stirring time after adding hydrochloric acid B and ammonium persulfate is 5-8 hours.

8. A ruthenium-doped β-manganese dioxide catalyst with a conductive layer prepared by the preparation method according to any one of claims 1-7.

9. The application of the ruthenium-doped β-manganese dioxide catalyst with a conductive layer as described in claim 8 in the electrolysis of water to produce hydrogen.

10. The application according to claim 9, characterized in that, The ruthenium-doped β-manganese dioxide catalyst coated with the conductive layer serves as the anode catalyst for the proton exchange membrane electrolyzer.

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