Rare earth element ruthenium-based composite catalyst as well as preparation method and application thereof

Abstract

The invention discloses a rare earth element ruthenium-based composite catalyst as well as a preparation method and application thereof. The preparation method of the rare earth element ruthenium-based composite catalyst comprises the following steps: (1) mixing and grinding rare earth metal salt, a ruthenium source, a conductive carbon material and an additive to obtain a uniform precursor material; and (2) putting the precursor material into a microwave reactor, and carrying out microwave reaction to prepare the rare earth element ruthenium-based composite catalyst. The rare earth element ruthenium-based composite catalyst prepared by the preparation method disclosed by the invention has excellent activity and wide application prospect when being used as an electrocatalytic water decomposition oxygen evolution electrode material.

Description

Technical Field

[0001] The invention relates to a preparation method of a rare earth element ruthenium-based composite catalyst and application of the composite catalyst in an anode reaction of an acidic water electrolysis system, belonging to the field of catalytic materials. Background Art

[0002] In the context of the "dual carbon" goal, hydrogen, as a clean and high-energy-density carrier, will play an important role in the transformation of the energy structure. Proton exchange membrane (PEM) water electrolysis hydrogen production technology has the advantages of high current density, high hydrogen purity, fast response speed, and high conversion efficiency. It is a very promising method for preparing green hydrogen (Ni et al. Nano Energy, 2020, 78, 105392; Liang et al. Environ. Chem. Lett., 2022, 20, 3429), but its strong acidity and high oxidizing working environment of the anode put forward high requirements on the stability of the catalyst. At present, commercial anodes are mainly based on iridium-based catalysts, which have good stability, but low reserves and high prices (Liu et al. J. Mater. Chem. A, 2022, 10, 13170; Zhu et al. Small 2022, 2205495). The theoretical oxygen evolution performance of ruthenium-based catalysts is higher than that of iridium-based catalysts, but their stability is poor. Under oxidizing conditions, ruthenium is easily oxidized to a higher valence state and then dissolved, resulting in reduced catalyst activity (Lu et al. J. Energy Chem., 2023, 85, 220; Liu et al. Small 2023, 2304889). By compounding rare earth metal elements with special 4f electron configurations, it is expected to form a stable rare earth metal-ruthenium compound structure, which improves the performance of ruthenium-based catalysts while reducing the content of precious metal ruthenium, ultimately saving the raw material cost of the catalyst (Yagi et al. Small 2022, 18, 2202439; Liu et al. Nat. Commun. 2022, 13, 4106). However, there are currently few synthetic methods for rare earth element ruthenium-based multi-component composite catalysts, and the material preparation process is cumbersome. High-performance acidic oxygen evolution reaction catalysts for batch preparation still need to be developed. Summary of the invention

[0003] The present invention provides the following technical solutions:

[0004] A method for preparing a rare earth element ruthenium-based composite catalyst, the preparation method comprising the following steps:

[0005] (1) mixing and grinding a rare earth metal salt with a ruthenium source, a conductive carbon material and an additive to obtain a uniform precursor material;

[0006] (2) Placing the precursor material in a microwave reactor and performing microwave reaction to obtain the rare earth element ruthenium-based composite catalyst.

[0007] According to an embodiment of the present invention, in step (1), the rare earth metal salt contains at least one of the following rare earth elements: at least one of lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, and ytterbium. Preferably, the rare earth metal salt is selected from at least one of the nitrates of the rare earth elements, the sulfates of the rare earth elements, the acetates of the rare earth elements, the chlorides of the rare earth elements, and the carbonyl salts of the rare earth elements.

[0008] According to an embodiment of the present invention, in step (1), the ruthenium source is at least one of ruthenium chloride, ruthenium carbonyl, ruthenium oxide, ruthenium oxalate, ruthenium nitrate, and bis(cyclopentadienyl)ruthenium.

[0009] According to an embodiment of the present invention, in step (1), the conductive carbon material is at least one of carbon tubes, graphite powder, carbon black, hard carbon, and carbon fiber.

[0010] According to an embodiment of the present invention, in step (1), the complexing agent is selected from at least one of citric acid, phosphoric acid and urea.

[0011] According to an embodiment of the present invention, in step (1), the mass ratio of the rare earth metal salt to the conductive carbon material is 0.1-5, for example, 0.5, 1, 2, 3, 4.

[0012] According to an embodiment of the present invention, in step (1), the molar ratio of the rare earth metal salt to the ruthenium source is 0.1-10, for example, 0.5:1, 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1.

[0013] According to an embodiment of the present invention, in step (1), the additive accounts for 0.1-50 wt% of the mass of the precursor material, for example, 10 wt%, 20 wt%, 30 wt%.

[0014] According to an embodiment of the present invention, in step (1), the precursor material is in powder form.

[0015] According to an embodiment of the present invention, in step (2), the conditions of the microwave reaction include: a temperature of 10-100°C (for example, 20°C, 30°C, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C); an atmosphere of one of air, oxygen, nitrogen, and argon; a microwave power range of 100-1000W (for example, 200W, 300W, 400W, 500W, 600W, 700W, 800W, 900W); and a microwave duration range of 1-1800 seconds (for example, 10 seconds, 50 seconds, 100 seconds, 500 seconds, 1000 seconds, 1500 seconds).

[0016] According to an embodiment of the present invention, in step (2), the microwave reaction is performed at least once. Preferably, the microwave reaction includes performing a microwave synthesis under a single power and time condition, or performing multiple microwave syntheses continuously. Further, the multiple microwave syntheses refer to performing a microwave reaction at least 2 times or more, and when performing multiple microwave syntheses, the microwave power and time of each time are independent of each other and can be the same or different.

[0017] The invention provides a rare earth element ruthenium-based composite catalyst, and the rare earth element ruthenium-based composite catalyst is obtained by the above-mentioned preparation method.

[0018] According to an embodiment of the present invention, the components of the rare earth element ruthenium-based composite catalyst are oxides and / or carbides of multi-metals; the multi-metals include ruthenium and the above-mentioned rare earth elements.

[0019] According to the embodiment of the present invention, the ruthenium in the components of the rare earth element ruthenium-based composite catalyst is not easily lost under acidic conditions and has excellent stability.

[0020] The present invention also provides the use of the rare earth element ruthenium-based composite catalyst in electrocatalytic decomposition of water to produce oxygen, preferably for the anode.

[0021] The present invention also provides a method for producing oxygen by electrocatalytically decomposing water. Under acidic conditions, the rare earth element ruthenium-based composite catalyst is used as an anode for electrolyzing water.

[0022] Beneficial Effects

[0023] The present invention has the following advantages:

[0024] 1. The preparation method provided can produce a rare earth element ruthenium-based composite catalyst. This method has wide universality, easy conditions to control, easy to operate, and can quickly and efficiently prepare catalysts in batches.

[0025] 2. The element composition, content, and ratio of the prepared rare earth element ruthenium-based composite catalyst are easy to adjust and the structure is controllable, and can be adjusted according to the different requirements of the catalytic reaction.

[0026] 3. The prepared rare earth element ruthenium-based composite catalyst exhibits excellent catalytic reaction performance and structural stability in the acidic electrocatalytic water decomposition system.

[0027] 4. This type of material has potential application prospects in the field of water electrolysis to produce hydrogen. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 These are transmission electron microscope morphology illustrations of the ruthenium-based catalyst (ab) not containing rare earth elements prepared in Comparative Example 1 and the rare earth element ruthenium-based composite catalyst (cd) prepared in Example 4, wherein the magnification of images a and c is 80,000 times, and the magnification of images b and d is 200,000 times.

[0029] Figure 2 This is the XRD characterization structure diagram of the rare earth element ruthenium-based composite catalyst prepared in Example 4.

[0030] Figure 3 This is the element distribution diagram of the rare earth element ruthenium-based composite catalyst prepared in Example 4.

[0031] Figure 4 This is a comparison chart of the performance of the oxygen evolution reaction in acidic water electrolysis in Application Example 1.

[0032] Figure 5 This is a comparison chart of the performance of the oxygen evolution reaction in acidic water electrolysis in Application Example 2.

[0033] Figure 6 This is a comparison chart of the performance of the acidic water electrolysis oxygen evolution reaction in Application Example 3. DETAILED DESCRIPTION

[0034] The technical scheme of the present invention will be further described in detail below in conjunction with specific embodiments. It should be understood that the following embodiments are only exemplary descriptions and explanations of the present invention and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are included in the scope that the present invention is intended to protect.

[0035] Unless otherwise specified, the raw materials and reagents used in the following examples are commercially available or can be prepared by known methods.

[0036] The products of Examples 1-12 of the present invention were detected by the following instruments and methods:

[0037] The morphology of the catalyst prepared in the example was characterized by transmission electron microscopy (TEM), and the structural composition information of the catalyst prepared in the example was characterized by X-ray diffractometer (XRD) and inductively coupled plasma (ICP);

[0038] The oxygen evolution performance of Examples 1-12 was measured in an acidic electrocatalytic water decomposition system.

[0039] Example 1

[0040] 1. Weigh 1 gram of ruthenium chloride, 1 gram of cerium nitrate, 1 gram of carbon black and 0.5 gram of citric acid raw materials, mix the four materials, put them into a mortar and grind them evenly to obtain a microwave precursor material.

[0041] 2. Take the microwave precursor material in step 1, place it in a microwave reactor and spread it out flatly. Under room temperature and air atmosphere, set the microwave power to 600 W, the microwave reaction time to 200 seconds, and the microwave program to once.

[0042] 3. After the reaction is completed, take out the sample powder to obtain the rare earth element ruthenium-based composite catalyst.

[0043] Example 2

[0044] 1. Weigh 1 g of ruthenium chloride, 0.1 g of lanthanum nitrate, 0.5 g of carbon black and 0.2 g of citric acid raw materials, mix the four materials, put them into a mortar and grind them evenly to obtain a microwave precursor material.

[0045] 2. Take the microwave precursor material in step 1, place it in a microwave reactor and spread it out flatly. Under room temperature and air atmosphere, set the microwave power to 600 W, the microwave reaction time to 200 seconds, and the microwave program to once.

[0046] 3. After the reaction is completed, take out the sample powder to obtain the rare earth element ruthenium-based composite catalyst.

[0047] Example 3

[0048] 1. Weigh 1 g of ruthenium oxide, 2 g of cerium acetate, 2 g of graphite powder and 0.2 g of citric acid raw materials, mix the four materials, put them into a mortar and grind them evenly to obtain a microwave precursor material.

[0049] 2. Take the microwave precursor material in step 1, place it in a microwave reactor and spread it out flatly. Under room temperature and air atmosphere, set the microwave power to 600 W, the microwave reaction time to 300 seconds, and the microwave program to once.

[0050] 3. After the reaction is completed, take out the sample powder to obtain the rare earth element ruthenium-based composite catalyst.

[0051] Example 4

[0052] 1. Weigh 1 gram of carbonyl ruthenium, 1 gram of lanthanum acetate, 1 gram of carbon tube and 0.5 gram of citric acid raw materials, mix the four materials, put them into a mortar and grind them evenly to obtain a microwave precursor material.

[0053] 2. Take the microwave precursor material in step 1, place it in a microwave reactor and spread it out flatly. Under room temperature and air atmosphere, set the microwave power to 900 W, the microwave reaction time to 20 seconds, and the microwave program to once.

[0054] 3. After the reaction is completed, take out the sample powder to obtain the rare earth element ruthenium-based composite catalyst.

[0055] The transmission electron microscope image of the rare earth element ruthenium-based composite catalyst of Example 4 is as follows: Figure 1 As shown in a and b, the prepared rare earth element ruthenium-based composite material is distributed on the outer wall of the carbon tube, and has no significant difference in morphology compared with the ruthenium-based catalyst without rare earth elements (Comparative Example 1). Figure 2 The XRD results show that the rare earth element ruthenium-based composite catalyst of Example 4 is composed of oxides of rare earth element lanthanum and precious metal ruthenium. The content of each element in the rare earth element ruthenium-based composite catalyst of Example 4 is as follows: Figure 3 As shown, it is proved that the catalyst contains lanthanum and ruthenium elements, and this result is confirmed by the XRD structural composition analysis.

[0056] Example 5

[0057] 1. Weigh 1 gram of carbonyl ruthenium, 0.5 gram of cerium acetate, 1 gram of carbon tube and 0.5 gram of citric acid raw materials, mix the four materials, put them into a mortar and grind them evenly to obtain a microwave precursor material.

[0058] 2. Take the microwave precursor material in step 1, place it in a microwave reactor and spread it out flatly. Under room temperature and air atmosphere, set the microwave power to 900 W, the microwave reaction time to 20 seconds, and the microwave program to once.

[0059] 3. After the reaction is completed, take out the sample powder to obtain the rare earth element ruthenium-based composite catalyst.

[0060] Example 6

[0061] 1. Weigh 1 gram of carbonyl ruthenium, 0.5 gram of praseodymium nitrate, 1 gram of carbon tubes and 0.5 gram of citric acid raw materials, mix the four materials, put them into a mortar and grind them evenly to obtain a microwave precursor material.

[0062] 2. Take the microwave precursor material in step 1, place it in a microwave reactor and spread it out flatly. Under room temperature and air atmosphere, set the microwave power to 900 W, the microwave reaction time to 20 seconds, and the microwave program to once.

[0063] 3. After the reaction is completed, take out the sample powder to obtain the rare earth element ruthenium-based composite catalyst.

[0064] The above Examples 1-6 are examples of adjusting the types of rare earth metal salts, ruthenium sources and conductive carbon materials, indicating that under the regulation of a single variable, by changing the types of each component, the corresponding rare earth element ruthenium-based composite catalyst can be prepared. It can be seen that the preparation method of the present invention can be applied to the preparation of ruthenium-based composite materials of various rare earth elements, and its oxygen evolution reaction performance is verified and explained in the application examples.

[0065] Example 7

[0066] 1. Weigh 1 gram of carbonyl ruthenium, 0.5 gram of lanthanum acetate, 1 gram of carbon tube and 0.5 gram of citric acid raw materials, mix the four materials, put them into a mortar and grind them evenly to obtain a microwave precursor material.

[0067] 2. Take the microwave precursor material in step 1, place it in a microwave reactor and spread it out flatly. Under room temperature and air atmosphere, set the microwave power to 900 W, the microwave reaction time to 20 seconds, and the microwave program to once.

[0068] 3. After the reaction is completed, take out the sample powder to obtain the rare earth element ruthenium-based composite catalyst.

[0069] Example 8

[0070] 1. Weigh 0.5 g of carbonyl ruthenium, 1 g of lanthanum acetate, 1 g of carbon tubes and 0.5 g of citric acid raw materials, mix the four materials, put them into a mortar and grind them evenly to obtain a microwave precursor material.

[0071] 2. Take the microwave precursor material in step 1, place it in a microwave reactor and spread it out flatly. Under room temperature and air atmosphere, set the microwave power to 900 W, the microwave reaction time to 40 seconds, and the microwave program to once.

[0072] 3. After the reaction is completed, take out the sample powder to obtain the rare earth element ruthenium-based composite catalyst.

[0073] The above Examples 4, 7-8 are about the modulation of the content of rare earth metal salt and ruthenium source in the microwave precursor material, indicating that under the regulation of a single variable, by changing the content of each component, the corresponding rare earth element ruthenium-based composite catalyst can be prepared, that is, the preparation method designed in the present invention can be applied to the preparation of composite catalysts with different metal contents, and its oxygen evolution reaction performance is verified and illustrated in the application examples.

[0074] Example 9

[0075] 1. Weigh 1 gram of carbonyl ruthenium, 0.5 gram of lanthanum acetate, 1 gram of carbon tube and 0.5 gram of citric acid raw materials, mix the four materials, put them into a mortar and grind them evenly to obtain a microwave precursor material.

[0076] 2. Take the microwave precursor material in step 1, place it in a microwave reactor and spread it out flatly. Under room temperature and air atmosphere, set the microwave power to 700 W, the microwave reaction time to 300 seconds, and the microwave program to once.

[0077] 3. After the reaction is completed, take out the sample powder to obtain the rare earth element ruthenium-based composite catalyst.

[0078] Example 10

[0079] 1. Weigh 1 gram of carbonyl ruthenium, 0.5 gram of lanthanum acetate, 1 gram of carbon tube and 0.5 gram of citric acid raw materials, mix the four materials, put them into a mortar and grind them evenly to obtain a microwave precursor material.

[0080] 2. Take the microwave precursor material in step 1, place it in a microwave reactor and spread it out flatly. Under room temperature and air atmosphere, set the microwave power to 500 W, the microwave reaction time to 1000 seconds, and the microwave program to once.

[0081] 3. After the reaction is completed, take out the sample powder to obtain the rare earth element ruthenium-based composite catalyst.

[0082] Embodiment 11

[0083] 1. Weigh 1 gram of carbonyl ruthenium, 0.5 gram of lanthanum acetate, 1 gram of carbon tube and 0.5 gram of citric acid raw materials, mix the four materials, put them into a mortar and grind them evenly to obtain a microwave precursor material.

[0084] 2. Take the microwave precursor material in step 1, place it in a microwave reactor and spread it out flatly. Under room temperature and air atmosphere, set the microwave power to 900 W, the microwave reaction time to 40 seconds, and the microwave program to once.

[0085] 3. After the reaction is completed, take out the sample powder to obtain the rare earth element ruthenium-based composite catalyst.

[0086] Example 12

[0087] 1. Weigh 1 gram of carbonyl ruthenium, 0.5 gram of lanthanum acetate, 1 gram of carbon tube and 0.5 gram of citric acid raw materials, mix the four materials, put them into a mortar and grind them evenly to obtain a microwave precursor material.

[0088] 2. Take the microwave precursor material in step 1, place it in a microwave reactor and spread it out flatly. Under room temperature and air atmosphere, set the microwave power to 900 W, the microwave reaction time to 10 seconds, and the microwave program to once.

[0089] 3. After the reaction is completed, take out the sample powder to obtain the rare earth element ruthenium-based composite catalyst.

[0090] Example 13

[0091] 1. Weigh 1 gram of carbonyl ruthenium, 0.5 gram of lanthanum acetate, 1 gram of carbon tube and 0.5 gram of citric acid raw materials, mix the four materials, put them into a mortar and grind them evenly to obtain a microwave precursor material.

[0092] 2. Take the microwave precursor material in step 1, place it in a microwave reactor and spread it flat. Under room temperature and air atmosphere, set the microwave power to 600 W, the microwave reaction time to 300 seconds, 750 W, the microwave reaction time to 120 seconds, and then the microwave power to 900 W, the microwave time to 30 seconds. Set it to a three-step microwave program and perform the set step program twice.

[0093] 3. After the reaction is completed, take out the sample powder to obtain the rare earth element ruthenium-based composite catalyst.

[0094] The above Examples 9-13 are settings and adjustments for the power, time, and program flow in the microwave conditions, indicating that by changing the microwave conditions under the control of a single variable, the corresponding rare earth element ruthenium-based composite catalyst can be prepared within the set range, and its oxygen evolution reaction performance is verified and illustrated in the application examples.

[0095] Comparative Example 1

[0096] 1. Weigh 1 gram of carbonyl ruthenium, 1 gram of carbon tubes and 0.5 gram of citric acid raw material, mix the four materials, put them into a mortar and grind them evenly to obtain a microwave precursor material.

[0097] 2. Take the microwave precursor material in step 1, place it in a microwave reactor and spread it out flatly. Under room temperature and air atmosphere, set the microwave power to 900 W, the microwave reaction time to 40 seconds, and the microwave program to once.

[0098] 3. After the reaction is completed, take out the sample powder to obtain a ruthenium-based catalyst without rare earth components.

[0099] Comparative Example 2

[0100] 1. Weigh 1 gram of ruthenium chloride, 1 gram of carbon black and 0.5 gram of citric acid raw materials, mix the four materials, put them into a mortar and grind them evenly to obtain a microwave precursor material.

[0101] 2. Take the microwave precursor material in step 1, place it in a microwave reactor and spread it out flatly. Under room temperature and air atmosphere, set the microwave power to 300 W, the microwave reaction time to 400 seconds, and the microwave program to once.

[0102] 3. After the reaction is completed, take out the sample powder to obtain a ruthenium-based catalyst without rare earth components.

[0103] Application Example 1

[0104] The rare earth element ruthenium-based composite catalyst of the above-mentioned Example 4, the catalyst obtained in Comparative Example 1, and the commercial iridium black catalyst were respectively used as anode catalysts in the acidic water electrolysis system and recorded as test catalysts to demonstrate the application potential of the rare earth element ruthenium-based composite catalyst of the present invention.

[0105] 1. Test system construction: The test device is a three-electrode system, the reference electrode is Ag / AgCL (saturated KCl solution), the counter electrode is a carbon rod, the working electrode is a glassy carbon electrode with 1 mg / cm2 of test catalyst drop-coated, and the electrolyte is 0.5MH2SO4 solution. A 50mL single-cell electrolytic cell is used during the test.

[0106] 2. Catalytic performance evaluation method: The temperature of the electrolytic cell is maintained at room temperature, and the oxygen evolution performance of the catalyst is evaluated by polarization curves. The current density of the catalyst with / without rare earth elements at the same potential is compared. The polarization curve scanning rate is 3 minutes / time. After 10 tests, that is, the oxidation reaction is carried out for 30 minutes, the change trend of the sample polarization curve is compared, and the specific test results Figure 4 As shown, the test result of the polarization curve test of the rare earth element ruthenium-based composite catalyst of Example 4 for the first time is recorded as "Example 4", and the test result of the reciprocating polarization curve test after 30 minutes of scanning is recorded as "Example 4-30mim"; the test result of the polarization curve test of the ruthenium-based catalyst without rare earth component of Comparative Example 1 for the first time is recorded as "Comparative Example 1", and the test result of the reciprocating polarization curve test after 30 minutes of scanning is recorded as "Comparative Example 1-30mim".

[0107] By comparison, it can be seen that the oxygen evolution performance of the ruthenium-based composite catalyst containing rare earth element components is better than that of the ruthenium-based composite catalyst without rare earth elements, proving that the introduction of rare earth elements is conducive to improving the catalytic performance of the ruthenium-based catalyst and is better than the commercial iridium black catalyst. After the polarization curve test is carried out for a certain period of time, the performance attenuation degree of Example 4 is much lower than that of Comparative Example 1, indicating that after the ruthenium-based catalyst is composited with a rare earth element compound, the structural stability in the acidic oxygen evolution reaction is significantly enhanced.

[0108] Application Example 2

[0109] The catalysts obtained in Examples 4, 5 and 6 were used as anode catalysts in an acidic water electrolysis system and recorded as test catalysts, demonstrating the application potential of ruthenium-based composite catalysts of different rare earth element types.

[0110] 1. Test system construction: The test device is a three-electrode system, the reference electrode is Ag / AgCL (saturated KCl solution), the counter electrode is a carbon rod, the working electrode is a glassy carbon electrode with a test catalyst drop-coated, and the electrolyte is a 0.5M H2SO4 solution. A 50mL single-cell electrolytic cell is used during the test.

[0111] 2. Catalytic performance evaluation method: The temperature of the electrolytic cell is maintained at room temperature, and the oxygen evolution performance of the catalyst is evaluated by polarization curves. The current density of catalysts with different metal contents at the same potential is compared. The specific test results Figure 5 shown.

[0112] By comparison, it can be seen that adjusting the type of rare earth element will affect the performance of its oxygen evolution reaction with ruthenium-based composite catalyst. The composite catalyst formed by rare earth metal lanthanum and ruthenium is preferred, which is conducive to the preparation of catalyst materials with higher activity.

[0113] Application Example 3

[0114] The catalysts obtained in Examples 4 and 11-12 were used as anode catalysts in an acidic water electrolysis system and recorded as test catalysts to demonstrate the application potential of composite catalysts with different ruthenium contents.

[0115] 1. Test system construction: The test device is a three-electrode system, the reference electrode is Ag / AgCL (saturated KCl solution), the counter electrode is a carbon rod, the working electrode is a glassy carbon electrode with a test catalyst drop-coated, and the electrolyte is a 0.5M H2SO4 solution. A 50mL single-cell electrolytic cell is used during the test.

[0116] 2. Catalytic performance evaluation method: The temperature of the electrolytic cell is maintained at room temperature. The oxygen evolution performance of the catalysts prepared with different microwave durations is evaluated by polarization curves. The current density of different catalysts at the same potential is compared. The specific test results Figure 6 shown.

[0117] By comparison, it can be seen that different microwave times will affect the oxygen evolution performance of the prepared samples. It is speculated that different microwave synthesis times will affect the number of bonds between rare earth elements and ruthenium elements, affect the consistency of the redundant composite catalyst structure, and thus affect the oxygen evolution performance of the material. The preferred microwave synthesis conditions are 900W and the microwave time is 40 seconds, which is conducive to the preparation of catalyst materials with higher activity.

[0118] The above is a description of the exemplary embodiments of the present invention. However, the protection scope of the present application is not limited to the above embodiments. Any modification, equivalent substitution, improvement, etc. made by those skilled in the art within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing a rare earth element ruthenium-based composite catalyst, characterized in that: The preparation method comprises the following steps: (1) mixing and grinding a rare earth metal salt with a ruthenium source, a conductive carbon material and an additive to obtain a uniform precursor material; (2) Placing the precursor material in a microwave reactor and performing microwave reaction to obtain the rare earth element ruthenium-based composite catalyst.

2. The preparation method according to claim 1, characterized in that: In step (1), the rare earth metal salt contains at least one of the following rare earth elements: at least one of lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium and ytterbium. Preferably, in step (1), the ruthenium source is at least one of ruthenium chloride, carbonyl ruthenium, ruthenium oxide, ruthenium oxalate, ruthenium nitrate and bis(cyclopentadienyl)ruthenium.

3. The preparation method according to claim 1 or 2, characterized in that: In step (1), the conductive carbon material is at least one of carbon tubes, graphite powder, carbon black, hard carbon, and carbon fiber. Preferably, in step (1), the complexing agent is selected from at least one of citric acid, phosphoric acid and urea.

4. The preparation method according to any one of claims 1 to 3, characterized in that In step (1), the mass ratio of the rare earth metal salt to the conductive carbon material is 0.1-5. Preferably, in step (1), the molar ratio of the rare earth metal salt to the ruthenium source is 0.1-10.

5. The preparation method according to any one of claims 1 to 4, characterized in that: In step (1), the additive accounts for 0.1-50 wt % of the mass of the precursor material. Preferably, in step (1), the precursor material is in powder form.

6. The preparation method according to any one of claims 1 to 5, characterized in that: In step (2), the conditions for the microwave reaction include: a temperature of 10-100° C.; an atmosphere of one of air, oxygen, nitrogen, and argon; a microwave power range of 100-1000 W; and a microwave duration range of 1-1800 seconds. Preferably, in step (2), the microwave reaction is performed at least once.

7. A rare earth element ruthenium-based composite catalyst, characterized in that: The rare earth element ruthenium-based composite catalyst is obtained by the preparation method described in any one of claims 1-6.

8. The rare earth element ruthenium-based composite catalyst according to claim 7, characterized in that: The rare earth element ruthenium-based composite catalyst comprises oxides and / or carbides of multi-metal components; the multi-metal components include ruthenium and rare earth elements. Preferably, the rare earth element ruthenium-based composite catalyst has excellent stability because the ruthenium in the components is not easily lost under acidic conditions.

9. Use of the rare earth element ruthenium-based composite catalyst according to claim 7 or 8 in electrocatalytic decomposition of water to produce oxygen.

10. A method for producing oxygen by electrocatalytic decomposition of water, characterized in that: Under acidic conditions, the rare earth element ruthenium-based composite catalyst described in claim 7 or 8 is used as the anode for water electrolysis.

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