Preparation method and application of rare earth element doped ruthenium oxide catalyst

Abstract

The invention discloses a preparation method and application of a rare earth element doped ruthenium oxide catalyst, and the preparation method comprises the following steps: (1) dissolving a rare earth metal salt, a ruthenium metal salt, dopamine hydrochloride and a Tris-HCl buffer agent in water to obtain a mixed solution, and carrying out in-situ polymerization reaction, solid-liquid separation and drying to obtain a powder precursor; and (2) carrying out high-temperature calcination on the powder precursor obtained in the step (1) to obtain the rare earth doped ruthenium oxide catalyst. Rare earth metal salt and ruthenium salt precursors are dispersed on an in-situ constructed porous carbon substrate, and the rare earth element doped ruthenium oxide nanosheet is generated by oxidation under a high-temperature condition through a self-sacrifice template method. The method has the characteristics of high efficiency and no pollution. The rare earth element doped ruthenium oxide disclosed by the invention is used as a catalyst for the anodic reaction of the acidic electrolyzed water, and shows excellent catalytic activity and wide application prospect.

Description

Technical Field

[0001] This invention belongs to the field of catalytic materials and relates to a method for preparing a rare earth element-doped ruthenium oxide catalyst and its application. Background Technology

[0002] Proton exchange membrane electrolysis (PEM) water splitting technology is widely regarded as a key technological path for the large-scale production of green hydrogen due to its fast response, flexible load adjustment, and high hydrogen purity. However, the commercialization of this technology is currently severely constrained by the availability of core materials (especially the oxygen evolution reaction catalyst at the anode), which are highly dependent on the rare but scarce precious metal iridium (Int. J. Hydrog. Energy 2013, 38, 4901; Science 2016, 353, 1011). To address these technical challenges, ruthenium oxide has attracted attention due to its theoretically higher intrinsic activity in the oxygen evolution reaction. However, under the strong acidity and high potential conditions of practical applications, the ruthenium oxide crystal structure is unstable, easily transforming into high-valence soluble ruthenium oxide and dissolving, leading to rapid loss of active sites and collapse of the catalyst layer structure. This results in stability far below the requirements of industrial applications (ACS Catal. 2012, 2, 1765; Adv. Mater. 2019, 31, 1900510). Based on the unique 4f electron configuration and strong oxygen affinity of rare earth metals, introducing them into the ruthenium oxide lattice can effectively fix the ruthenium active centers and regulate its electronic structure, thereby significantly enhancing the stability of the ruthenium oxide lattice during the reaction process and reducing the ruthenium content in the catalyst, thus achieving the dual goals of cost reduction and efficiency improvement (C). hem. Rev. 2022, 122, 6, 5519). However, the uneven distribution of rare earth elements in currently synthesized rare earth-doped ruthenium oxide materials leads to the easy aggregation of ruthenium oxide nanoparticles and difficulty in precisely controlling their size, thus limiting their specific surface area and the number of exposed active sites. Nat. Commun. 2020, 11 (1278). Therefore, developing highly efficient rare earth-ruthenium-based anode catalysts that combine high activity and high stability and are suitable for the acidic environment of PEM electrolyzers remains a key technical challenge that urgently needs to be addressed in this field. Summary of the Invention

[0003] To address the aforementioned technical problems, this invention provides a method for preparing rare-earth-doped ruthenium oxide, comprising the following steps: (1) A mixed solution was obtained by dissolving rare earth metal salt, ruthenium metal salt, dopamine hydrochloride and Tris-HCl buffer in water, followed by in-situ polymerization, solid-liquid separation and drying to obtain a powder precursor; (2) The powder precursor obtained in step (1) is calcined at high temperature to obtain rare earth-doped ruthenium oxide catalyst.

[0004] According to an embodiment of the present invention, in step (1), the mass ratio of rare earth metal salt to ruthenium metal salt is 1:(2~15), for example, 1:2, 1:5, 1:8, 1:10, 1:12 or 1:15.

[0005] According to an embodiment of the present invention, in step (1), the mass ratio of ruthenium metal salt to dopamine hydrochloride is 1:(2~50), for example, 1:5, 1:10, 1:20 or 1:40.

[0006] According to an embodiment of the present invention, in step (1), the rare earth element contained in the rare earth metal salt is at least one of lanthanum, cerium, praseodymium, neodymium, samarium, europium and gadolinium; the rare earth metal salt is at least one of rare earth metal nitrate, sulfate, acetate, chloride or carbonyl salt.

[0007] According to an exemplary embodiment of the present invention, in step (1), the ruthenium metal salt is at least one of ruthenium chloride, ruthenium carbonyl, ruthenium nitrate and ruthenium dicerocene.

[0008] According to an embodiment of the present invention, in step (1), the concentration of rare earth metal ions in the mixed solution is 0.1-10 mmol / L, for example 0.1 mol / L, 0.2 mol / L, 0.25 mol / L, 0.5 mol / L, 1 mol / L, 2 mol / L, 5 mol / L, 8 mol / L or 10 mol / L.

[0009] According to an embodiment of the present invention, in step (1), the concentration of ruthenium ions in the mixed solution is 0.001-1 mol / L, for example 0.001 mol / L, 0.005 mol / L, 0.01 mol / L, 0.05 mol / L, 0.1 mol / L, 0.2 mol / L, 0.25 mol / L, 0.5 mol / L or 1 mol / L.

[0010] According to an embodiment of the present invention, in step (1), the concentration of dopamine hydrochloride in the mixed solution is 0.01-0.5 mol / L, for example 0.01 mol / L, 0.0556 mol / L, 0.1 mol / L, 0.2 mol / L, 0.25 mol / L or 0.5 mol / L.

[0011] According to an embodiment of the present invention, in step (1), the concentration of the Tris-HCl buffer in the mixed solution is 0.01-0.5 mol / L, for example, 0.01 mol / L, 0.025 mol / L, 0.05 mol / L, 0.1 mol / L, 0.2 mol / L, 0.25 mol / L, or 0.5 mol / L. Further, the initial pH of the Tris-HCl buffer is 8.2-9.0, for example, 8.2, 8.5, 8.8, or 9.0.

[0012] According to an embodiment of the present invention, in step (1), the in-situ polymerization reaction is carried out under stirring. For example, the stirring time is 12-48 hours, such as 12 hours, 24 hours, 36 hours or 48 hours.

[0013] According to an embodiment of the present invention, in step (1), the solid-liquid separation can be vacuum filtration.

[0014] According to an embodiment of the present invention, in step (1), the drying temperature can be 40~100℃, for example 60℃; the drying time is 1~24h, for example 12h.

[0015] According to an embodiment of the present invention, in step (2), the calcination temperature is 200-450°C. o C, for example, 200 o C, 250 o C, 300 o C, 350 o C, 400 o C or 450 o C; calcination time is 1-12 hours, for example, 1 hour, 2 hours, 6 hours or 12 hours.

[0016] According to an embodiment of the present invention, step (2) further includes washing, solid-liquid separation (e.g., filtration), and drying of the product after high-temperature calcination. For example, the washing solvent is H2SO4. Alternatively, the concentration of the H2SO4 is 0.1~1M, for example, 0.5M. The drying temperature can be 40~100℃, for example, 60℃; the drying time is 1~24h, for example, 12h.

[0017] This invention provides a rare-earth element-doped ruthenium oxide prepared by the above-described method. The rare-earth element-doped ruthenium oxide of this invention has a nanosheet structure, and its ruthenium component is not easily lost under acidic conditions, resulting in excellent material stability.

[0018] This invention also provides an application of the aforementioned rare-earth element-doped ruthenium oxide in the electrocatalytic oxygen evolution reaction. For example, it can be used as a catalytic material for the anodic oxygen evolution reaction in an acidic water electrolysis hydrogen production system.

[0019] The present invention also provides an electrolysis system in which ruthenium oxide doped with the above-mentioned rare earth elements is used as the working electrode.

[0020] The beneficial effects of this invention are: 1. This invention disperses rare earth metal salts and ruthenium salt precursors on an in-situ constructed porous carbon substrate, and then oxidizes them under high temperature conditions using a self-sacrificial template method to generate rare earth element-doped ruthenium oxide nanosheets. The preparation method of this invention is applicable to the preparation of ruthenium oxide catalysts doped with different rare earth elements. This method has wide applicability, easily controllable conditions, and is easy to operate, enabling rapid and efficient batch preparation of rare earth element-doped ruthenium oxide catalysts.

[0021] 2. The rare earth elements in the rare earth element-doped ruthenium oxide prepared by this invention are uniformly distributed, and the size, morphology, and structure of the ruthenium oxide nanosheets are controllable and can be adjusted according to different requirements of the catalytic reaction.

[0022] 3. The rare earth element-doped ruthenium oxide prepared in this invention exhibits superior catalytic performance and structural stability as a catalyst in the acidic oxygen evolution reaction.

[0023] 4. The rare earth element-doped ruthenium oxide prepared by this invention has potential application prospects in the field of hydrogen production by water electrolysis. Attached Figure Description

[0024] Figure 1 This is a transmission electron microscope (TEM) image illustrating the morphology of the rare earth element-doped ruthenium oxide catalyst prepared in Example 7.

[0025] Figure 2 This is an elemental distribution diagram of the rare earth element-doped ruthenium oxide catalyst prepared in Example 7.

[0026] Figure 3 The image shows the XRD structure of the rare earth element-doped ruthenium oxide catalyst prepared in Example 7.

[0027] Figure 4 This is a diagram showing the elemental distribution of the rare earth element-doped ruthenium oxide catalyst prepared in Example 7.

[0028] Figure 5 This is a comparison chart showing the performance of the catalysts prepared in Example 1 and Comparative Example 1, as well as a commercial ruthenium dioxide catalyst, in the acidic water electrolysis oxygen evolution reaction.

[0029] Figure 6 The graph shows a comparison of the performance of the catalysts prepared in Examples 1, 3, 6, and 7 in the acidic water electrolysis oxygen evolution reaction.

[0030] Figure 7 This is a comparison chart of the performance of the catalysts prepared in Examples 7, 8, and 9 in the acidic water electrolysis oxygen evolution reaction. Detailed Implementation

[0031] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanatory 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 covered within the scope of protection intended by the present invention.

[0032] Unless otherwise stated, the raw materials and reagents used in the following examples are commercially available products or can be prepared by known methods.

[0033] Terminology Definitions and Explanations Unless otherwise defined, all scientific and technical terms herein have the same meaning as commonly understood by one of ordinary skill in the art to which the subject matter of the claims pertains. In the specification and claims of this application, unless otherwise stated, scientific and technical terms used herein have the meanings commonly understood by one of ordinary skill in the art. However, for a better understanding of this disclosure, definitions and explanations of some related terms are provided below. Furthermore, in the event of any discrepancy between the definitions and explanations of terms provided herein and the meanings commonly understood by one of ordinary skill in the art, the definitions and explanations provided herein shall prevail.

[0034] The term "room temperature" refers to room temperature in the conventional sense in this field, generally 10 to 30°C, preferably 25°C ± 5°C, such as 20°C, 25°C, or 30°C.

[0035] The products of Examples 1-10 of the present invention were tested using the following instruments and methods: The catalyst morphology was characterized by transmission electron microscopy (TEM), and the structural composition information of the catalyst was characterized by X-ray diffraction (XRD) and inductively coupled plasma (ICP). The oxygen evolution performance of the products obtained in Examples 1-10 was determined in an acidic electrocatalytic water splitting system.

[0036] Example 1 The preparation method of rare earth element-doped ruthenium oxide catalyst includes the following steps: 1. Add 20 mg cerium hydrochloride, 100 mg ruthenium chloride, 1 g dopamine hydrochloride, and 3 mL Tris-HCl pH buffer (1.5 mol / L, pH=8.8) to 100 mL deionized water. Stir at a constant speed for 12 hours, then filter. Incubate the product at 60 °C. o The resulting powder precursor was collected after drying at C for 12 hours.

[0037] 2. Take 0.2g of the precursor powder and heat it in air at 300°C. o Calcination at C temperature for 6 hours, acid washing with 0.5 M H2SO4 for 30 minutes, followed by filtration, and then sterilization at 60°C.o Cerium-doped ruthenium oxide catalyst was prepared by drying at C for 12 hours.

[0038] Example 2 The preparation method of rare earth element-doped ruthenium oxide catalyst includes the following steps: 1. Add 20 mg lanthanum acetate, 100 mg ruthenium carbonyl, 1 g dopamine hydrochloride, and 3 mL Tris-HCl pH buffer (1.5 mol / L, pH=8.8) to 100 mL deionized water. Stir at a constant speed for 12 hours, then filter. Incubate the product at 60 °C. o The resulting powder precursor was collected after drying at C for 12 hours.

[0039] 2. Take 0.2g of the precursor powder and heat it in air at 300°C. o Calcination at C temperature for 6 hours, acid washing with 0.5 M H2SO4 for 30 minutes, followed by filtration, and then sterilization at 60°C. o Lanthanum-doped ruthenium oxide catalyst was prepared by drying at C for 12 hours.

[0040] Example 3 The preparation method of rare earth element-doped ruthenium oxide catalyst includes the following steps: 1. Add 20 mg neodymium nitrate, 100 mg ruthenium nitrate, 1 g dopamine hydrochloride, and 3 mL Tris-HCl pH buffer (1.5 mol / L, pH=8.8) to 100 mL of deionized water. Stir at a constant speed for 12 hours, then filter. Incubate the product at 60 °C. o The resulting powder precursor was collected after drying at C for 12 hours.

[0041] 2. Take 0.2g of the precursor powder and heat it in air at 300°C. o Calcination at C temperature for 6 hours, acid washing with 0.5 M H2SO4 for 30 minutes, followed by filtration, and then sterilization at 60°C. o Neodymium-doped ruthenium oxide catalyst was prepared by drying at C for 12 hours.

[0042] Example 4 The preparation method of rare earth element-doped ruthenium oxide catalyst includes the following steps: 1. Add 10 mg neodymium nitrate, 100 mg ruthenium carbonyl, 0.5 g dopamine hydrochloride, and 1.5 mL Tris-HCl pH buffer (1.5 mol / L, pH=8.8) to 50 mL of deionized water. Stir at a constant speed for 12 hours, then filter. Incubate the product at 60 °C. o The resulting powder precursor was collected after drying at C for 12 hours.

[0043] 2. Take 0.2g of the precursor powder and heat it in air at 300°C. oCalcination at C temperature for 6 hours, acid washing with 0.5 M H2SO4 for 30 minutes, followed by filtration, and then sterilization at 60°C. o Neodymium-doped ruthenium oxide catalyst was prepared by drying at C for 12 hours.

[0044] Example 5 The preparation method of rare earth element-doped ruthenium oxide catalyst includes the following steps: 1. Add 20 mg cerium hydrochloride, 50 mg ruthenium chloride, 1 g dopamine hydrochloride, and 3 mL Tris-HCl pH buffer (1.5 mol / L, pH=8.8) to 100 mL deionized water. Stir at a constant speed for 12 hours, then filter. Incubate the product at 60 °C. o The resulting powder precursor was collected after drying at C for 12 hours.

[0045] 2. Take 0.2g of the precursor powder and heat it in air at 300°C. o Calcination at C temperature for 6 hours, acid washing with 0.5 M H2SO4 for 30 minutes, followed by filtration, and then sterilization at 60°C. o Cerium-doped ruthenium oxide catalyst was prepared by drying at C for 12 hours.

[0046] Example 6 The preparation method of rare earth element-doped ruthenium oxide catalyst includes the following steps: 1. Add 20 mg praseodymium nitrate, 200 mg ruthenium carbonyl, 2 g dopamine hydrochloride, and 6 mL Tris-HCl pH buffer (1.5 mol / L, pH=8.8) to 100 mL deionized water. Stir at a constant speed for 12 hours, then filter. Incubate the product at 60 °C. o The resulting powder precursor was collected after drying at C for 12 hours.

[0047] 2. Take 0.2g of the precursor powder and heat it in air at 300°C. o Calcination at C temperature for 6 hours, acid washing with 0.5 M H2SO4 for 30 minutes, followed by filtration, and then sterilization at 60°C. o Praseodymium-doped ruthenium oxide catalyst was prepared by drying at C for 12 hours.

[0048] Example 7 The preparation method of rare earth element-doped ruthenium oxide catalyst includes the following steps: 1. Add 50 mg lanthanum hydrochloride, 500 mg ruthenium chloride, 20 g dopamine hydrochloride, and 60 mL Tris-HCl pH buffer (1.5 mol / L, pH=8.8) to 1000 mL deionized water. Stir at a constant speed for 12 hours, then filter. Incubate the product at 60 °C. o The resulting powder precursor was collected after drying at C for 12 hours.

[0049] 2. Take 5g of precursor powder and heat it in air at 300°C. o Calcination at C temperature for 6 hours, acid washing with 0.5 M H2SO4 for 30 minutes, followed by filtration, and then sterilization at 60°C. o Lanthanum-doped ruthenium oxide catalyst was prepared by drying at C for 12 hours.

[0050] The transmission electron microscope (TEM) image and elemental distribution of the lanthanum-doped ruthenium oxide material prepared in this embodiment are as follows: Figure 1 and Figure 2 As shown in the figure, rare earth element-doped ruthenium oxide has a nanosheet structure with a size distribution in the range of 5-20 nanometers, and the rare earth elements are uniformly distributed in the ruthenium oxide lattice.

[0051] The XRD results of the lanthanum-doped ruthenium oxide prepared in this embodiment are as follows: Figure 3 As shown in the figure, the diffraction peaks are mainly ruthenium oxide, while the doping of rare earth elements caused the shift of the diffraction peaks.

[0052] The elemental contents of the lanthanum-doped ruthenium oxide prepared in this embodiment were determined by ICP as follows: Figure 4 As shown, this demonstrates that the lanthanum-doped ruthenium oxide prepared in this embodiment contains lanthanum and ruthenium elements, a result that is corroborated by EDS and XRD structural composition analyses.

[0053] Examples 1-7 show that by controlling the types and / or contents of rare earth metal salts, ruthenium sources, and dopamine hydrochloride, corresponding rare earth element-doped ruthenium oxide catalysts can be prepared. This indicates that the preparation method of the present invention can be applied to the preparation of various ruthenium oxide-based composite materials doped with different rare earth elements.

[0054] Example 8 The preparation method of rare earth element-doped ruthenium oxide catalyst includes the following steps: 1. Add 20 mg lanthanum hydrochloride, 100 mg ruthenium chloride, 1 g dopamine hydrochloride, and 3 mL Tris-HCl pH buffer (1.5 mol / L, pH=8.8) to 100 mL deionized water. Stir at a constant speed for 12 hours, then filter. Incubate the product at 60 °C. o The resulting powder precursor was collected after drying at C for 12 hours.

[0055] 2. Take 0.2g of the precursor powder and heat it in air at 200°C. o Calcination at C temperature for 6 hours, acid washing with 0.5 M H2SO4 for 30 minutes, followed by filtration, and then sterilization at 60°C. o Lanthanum-doped ruthenium oxide catalyst was prepared by drying at C for 12 hours.

[0056] Example 9 The preparation method of rare earth element-doped ruthenium oxide catalyst includes the following steps: 1. Add 20 mg lanthanum hydrochloride, 100 mg ruthenium chloride, 1 g dopamine hydrochloride, and 3 mL Tris-HCl pH buffer (1.5 mol / L, pH=8.8) to 100 mL deionized water. Stir at a constant speed for 12 hours, then filter. Incubate the product at 60 °C. o The resulting powder precursor was collected after drying at C for 12 hours.

[0057] 2. Take 0.2g of the precursor powder and heat it in air at 400°C. o Calcination at C temperature for 6 hours, acid washing with 0.5 M H2SO4 for 30 minutes, followed by filtration, and then sterilization at 60°C. o Lanthanum-doped ruthenium oxide catalyst was prepared by drying at C for 12 hours.

[0058] Example 10 The preparation method of rare earth element-doped ruthenium oxide catalyst includes the following steps: 1. Add 20 mg cerium hydrochloride, 100 mg ruthenium chloride, 1 g dopamine hydrochloride, and 3 mL Tris-HCl pH buffer (1.5 mol / L, pH=8.8) to 100 mL deionized water. Stir at a constant speed for 12 hours, then filter. Incubate the product at 60 °C. o The resulting powder precursor was collected after drying at C for 12 hours.

[0059] 2. Take 0.2g of the precursor powder and heat it in air at 300°C. o Calcination at C temperature for 12 hours, acid washing with 0.5 M H2SO4 for 30 minutes, followed by filtration, and then sterilization at 60°C. o Cerium-doped ruthenium oxide catalyst was prepared by drying at C for 12 hours.

[0060] Comparative Example 1 The preparation method of ruthenium oxide catalyst includes the following steps: 1. Add 100 mg ruthenium chloride, 1 g dopamine hydrochloride, and 3 mL Tris-HCl pH buffer (1.5 mol / L, pH=8.8) to 100 mL of deionized water. Stir at a constant speed for 12 hours, then filter. Incubate the product at 60 °C. o The resulting powder precursor was collected after drying at C for 12 hours.

[0061] 2. Take 0.2g of the precursor powder and heat it in air at 300°C. o Calcination at C temperature for 6 hours, acid washing with 0.5 M H2SO4 for 30 minutes, followed by filtration, and then sterilization at 60°C. o Ruthenium oxide catalyst was prepared by drying at C for 12 hours.

[0062] Comparative Example 2 20 mg of cerium hydrochloride, 100 mg of ruthenium chloride, and 3 mL of Tris-HCl pH buffer (1.5 mol / L, pH=8.8) were added to 100 mL of deionized water. After stirring at a constant speed for 12 hours and filtering, no solid sample was formed, thus the rare earth element-doped ruthenium oxide catalyst could not be prepared. This may be because no dopamine hydrochloride raw material was added, thus failing to polymerize in situ to form polydopamine in the first step. In contrast, in Example 1, the generated polydopamine uniformly dispersed the metal salt in the substrate. Under subsequent high-temperature calcination conditions, the polydopamine carbonized into carbon dioxide and volatilized, while the dispersed metal ions oxidized to form small-sized metal oxides. This indicates that dopamine hydrochloride is a necessary component for generating small-sized, well-dispersed, and highly active rare earth element-doped ruthenium oxide.

[0063] Comparative Example 3 Adding 20 mg of cerium hydrochloride, 100 mg of ruthenium chloride, and 1 g of dopamine hydrochloride to 100 mL of deionized water and stirring at a constant speed for 12 hours, followed by filtration, revealed no solid sample formation, indicating that the polymerization of dopamine hydrochloride failed. Therefore, it was impossible to prepare a rare-earth element-doped ruthenium oxide catalyst. This demonstrates that the pH buffer is crucial for maintaining the polymerization conditions of dopamine hydrochloride; only polydopamine formed under stable pH conditions exhibits a relatively homogeneous and reproducible structure.

[0064] Application Example 1 The cerium-doped ruthenium oxide prepared in Example 1, the ruthenium oxide obtained in Comparative Example 1, and the commercial iridium black (Maclean, CAS No. 7439-88-5) were used as anodic catalysts in an acidic water electrolysis system, demonstrating the application potential of rare earth element-doped ruthenium oxide catalysts.

[0065] 1. Test System Setup: The test setup was a three-electrode system. The reference electrode was Ag / AgCl (saturated KCl solution), the counter electrode was a carbon rod, and the working electrode was a glassy carbon electrode coated with the catalyst to be tested (5 mg of catalyst was dispersed in 980 μL of isopropanol solution, 20 μL of Nafion solution was added, and after sonication for 30 minutes, it was dropped onto a 5 mm diameter glassy carbon electrode, with a catalyst loading of 5 mg / cm³). 2 The electrolyte was a 0.5 M H2SO4 solution. A 50 mL single-cell electrolytic cell was used in the test.

[0066] 2. Catalytic performance evaluation method: The electrolytic cell temperature was maintained at room temperature. The oxygen evolution performance of the catalyst was evaluated by polarization curves. The current density of catalysts with and without rare earth elements at the same potential was compared, and the trend of polarization curve changes with reaction time was compared. Specific test results were presented. Figure 5As shown. The results indicate that the oxygen evolution performance of the rare-earth element-doped ruthenium oxide catalyst of this invention is superior to that of the ruthenium-based catalyst without rare-earth elements. This proves that the introduction of rare-earth elements in this invention is beneficial to improving the catalytic performance of the ruthenium-based catalyst and is superior to that of the commercial iridium black catalyst. After a certain period of polarization curve testing, the degree of oxygen evolution performance degradation of the rare-earth element-doped ruthenium oxide catalyst in Example 1 is much lower than that in Comparative Example 1. This indicates that the structural stability of the ruthenium-based catalyst in the acidic oxygen evolution reaction is also significantly enhanced after the rare-earth elements are combined.

[0067] Application Example 2 The rare earth element-doped ruthenium oxide obtained in Examples 1, 3, 6, and 7 was used as the anode catalyst in the acidic water electrolysis system to demonstrate the application potential of ruthenium oxide catalysts doped with different rare earth elements.

[0068] 1. Test System Setup: The test setup was a three-electrode system. The reference electrode was Ag / AgCl (saturated KCl solution), the counter electrode was a carbon rod, and the working electrode was a glassy carbon electrode coated with rare earth element-doped ruthenium oxide obtained in Examples 1, 3, 6, and 7, respectively (5 mg of catalyst was dispersed in 980 μL of isopropanol solution, 20 μL of Nafion solution was added, and after sonication for 30 minutes, it was dropped onto a glassy carbon electrode with a diameter of 5 mm, with a catalyst loading of 5 mg / cm³). 2 The electrolyte was a 0.5 M H2SO4 solution. A 50 mL single-cell electrolytic cell was used in the test.

[0069] 2. Catalytic performance evaluation method: The electrolytic cell temperature was maintained at room temperature, and the oxygen evolution performance of the catalyst was evaluated by polarization curves. The current density of catalysts with different metal contents at the same potential was compared. Specific test results were obtained. Figure 6 As shown. The results indicate that the present invention can affect the oxygen evolution reaction performance of rare earth element-doped ruthenium oxide as a catalyst by adjusting the type and doping amount of rare earth elements.

[0070] Application Example 3 The rare earth element-doped ruthenium oxide obtained in Examples 7, 8, and 9 was used as the anolyte catalyst in the acidic water electrolysis system, demonstrating the application potential of rare earth element-doped ruthenium oxide prepared at different calcination temperatures as a catalyst.

[0071] 1. Test System Setup: The test setup was a three-electrode system. The reference electrode was Ag / AgCl (saturated KCl solution), the counter electrode was a carbon rod, and the working electrode was a glassy carbon electrode coated with rare earth element-doped ruthenium oxide obtained in Examples 7, 8, and 9, respectively (5 mg of catalyst was dispersed in 980 μL of isopropanol solution, 20 μL of Nafion solution was added, and after sonication for 30 minutes, it was dropped onto a glassy carbon electrode with a diameter of 5 mm, with a catalyst loading of 5 mg / cm³). 2 The electrolyte was a 0.5 M H2SO4 solution. A 50 mL single-cell electrolytic cell was used in the test.

[0072] 2. Catalytic performance evaluation method: The electrolytic cell temperature was maintained at room temperature. The oxygen evolution performance of catalysts prepared at different calcination temperatures was evaluated by polarization curves. The current density of different catalysts at the same potential was compared. Specific test results were obtained. Figure 7 As shown in the figure, different calcination temperatures affect the oxygen evolution performance of the rare earth element-doped ruthenium oxide as an anode catalyst in an acidic water electrolysis system. This may be because the oxidation rate of the porous carbon template generated in situ differs at different calcination temperatures, thus affecting the morphology and size of the ruthenium oxide. Too low a temperature is not conducive to the carbon oxidation reaction, and the carbon template hinders the formation of ruthenium oxide active sites, resulting in an insufficient number of active sites. On the other hand, too high a temperature results in an excessively large size of the ruthenium oxide, reducing the number of edge active sites and thus affecting its reactivity. The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiments. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing rare earth element-doped ruthenium oxide, characterized in that, Includes the following steps: (1) A mixed solution was obtained by dissolving rare earth metal salt, ruthenium metal salt, dopamine hydrochloride and Tris-HCl buffer in water, followed by in-situ polymerization, solid-liquid separation and drying to obtain a powder precursor; (2) The powder precursor obtained in step (1) is calcined at high temperature to obtain rare earth-doped ruthenium oxide catalyst.

2. The preparation method according to claim 1, characterized in that, In step (1), the mass ratio of rare earth metal salt to ruthenium metal salt is 1:(2~15).

3. The preparation method according to claim 1 or 2, characterized in that, The mass ratio of ruthenium metal salt to dopamine hydrochloride is 1:(2~50).

4. The preparation method according to any one of claims 1-3, characterized in that, The rare earth element contained in the rare earth metal salt is at least one of lanthanum, cerium, praseodymium, neodymium, samarium, europium, and gadolinium; the rare earth metal salt is at least one of the rare earth metal nitrate, sulfate, acetate, chloride, or carbonyl salt.

5. The preparation method according to any one of claims 1-4, characterized in that, The ruthenium metal salt is at least one of ruthenium chloride, ruthenium carbonyl, ruthenium nitrate, and ruthenium dicerocene.

6. The preparation method according to any one of claims 1-5, characterized in that, The concentration of rare earth metal ions in the mixed solution is 0.1-10 mmol / L; And / or, the concentration of ruthenium ions in the mixed solution is 0.001-1 mol / L; And / or, the concentration of dopamine hydrochloride in the mixed solution is 0.01-0.5 mol / L.

7. The preparation method according to any one of claims 1-6, characterized in that... In step (2), the calcination temperature is 200-450°C. o C; calcination time is 1-12 hours.

8. A rare earth element-doped ruthenium oxide prepared by the preparation method according to any one of claims 1-7.

9. The application of the rare-earth element-doped ruthenium oxide as described in claim 8 in the electrocatalytic oxygen evolution reaction. For example, it can be used as a catalytic material for the anodic oxygen evolution reaction in an acidic water electrolysis hydrogen production system.

10. An electrolysis system wherein the rare earth element-doped ruthenium oxide of claim 8 is used as the working electrode.

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