Doping regulation type ruthenium-iridium-based electro-catalytic oxygen evolution catalyst and preparation method thereof

Abstract

The invention belongs to the technical field of preparation of electrocatalytic oxygen evolution catalysts, and particularly discloses a doping regulation type ruthenium-iridium-based electrocatalytic oxygen evolution catalyst and a preparation method thereof.The preparation method comprises the following steps that S1, ruthenium salt, iridium salt and doped metal salt are dispersed in a solvent, the doped metal salt is selected from one or more of yttrium salt, strontium salt, potassium salt, calcium salt, magnesium salt, scandium salt, gallium salt and aluminum salt; s2, preparing a precursor mixture; s3, performing heat treatment to obtain a solid product; and S4, washing and drying to obtain the metal element doped ruthenium-iridium-based electro-catalytic oxygen evolution catalyst. According to the doping regulation type ruthenium-iridium-based electro-catalysis oxygen evolution catalyst and the preparation method thereof, the process is simple, the universality is high, doping of multiple elements can be achieved only by replacing the doped metal salt, and the obtained catalyst has excellent acidic water electrolysis oxygen evolution activity and long circulation stability; and excessive phase splitting of the Y element and excessive lattice distortion of other elements can be avoided.

Description

Technical Field

[0001] This invention relates to the field of electrocatalytic oxygen evolution catalyst preparation technology, and in particular to a doped and regulated ruthenium-iridium based electrocatalytic oxygen evolution catalyst and its preparation method. Background Technology

[0002] With the global energy crisis and environmental pollution becoming increasingly severe, the development of clean and sustainable new energy conversion technologies has become a current research hotspot. Hydrogen production through water electrolysis is considered one of the most promising energy storage and conversion pathways because it can convert renewable energy sources (such as solar and wind power) into high-energy-density hydrogen. The oxygen evolution reaction (OER), as the core anode reaction in the water electrolysis process, suffers from a slow kinetic process that severely restricts the overall efficiency of the water electrolysis system. Therefore, developing efficient and stable OER electrocatalytic materials is crucial for promoting the large-scale application of water electrolysis hydrogen production technology.

[0003] In acidic water electrolysis systems, the selection of electrocatalysts is severely limited due to harsh operating conditions such as strong acid media and high operating potentials. Commercially available acidic OER catalysts mainly rely on oxides of the rare and precious metals ruthenium (Ru) and iridium (Ir). Among them, ruthenium-iridium composite oxides have become one of the optimal systems for balancing activity and stability due to the high catalytic activity of Ru and the excellent structural stability of Ir. However, pure ruthenium-iridium composite oxides still suffer from problems such as insufficient electronic structure regulation and easy loss of active sites during long-term reactions, making it difficult for their catalytic performance to meet the requirements of large-scale applications. Heterogeneous element doping has been proven to be an effective strategy for optimizing the electronic structure of ruthenium-iridium composite oxides, stabilizing the crystal structure, and simultaneously improving catalytic activity and cycle stability.

[0004] Existing methods for preparing doped ruthenium-iridium based catalysts have significant limitations: (1) Most preparation processes are highly targeted and can only achieve doping of a specific single element. It is difficult to flexibly replace the doping element to adapt to the performance requirements of different application scenarios, and the universality is poor. (2) The control precision of the doping element content is insufficient, and the amount of carrier and element characteristics are not considered together. When the doping element is Y, excessive doping can easily cause phase separation, while excessive doping of other elements may lead to lattice distortion. At the same time, improper carrier dosage will cause metal ion aggregation or residue, further affecting the catalytic performance. (3) The support used in some preparation methods is difficult to completely remove. The residual support components will affect the exposure of the catalyst active sites, thereby restricting the synergistic catalytic efficiency of the ruthenium-iridium composite system.

[0005] Therefore, the selection of doping elements, control of doping content, and proportion of support should work together to meet the performance requirements of ruthenium-iridium based catalysts. Developing a doped ruthenium-iridium based electrocatalytic oxygen evolution catalyst with strong universality (flexible replacement of doping elements and precise control of key parameters), simple preparation process, and high catalyst purity is of great significance for promoting the development of acidic water electrolysis hydrogen production technology. Summary of the Invention

[0006] The purpose of this invention is to provide a doped and regulated ruthenium-iridium-based electrocatalytic oxygen evolution catalyst and its preparation method. The process is simple and universal. Multiple element doping can be achieved by simply replacing the doping metal salt. The resulting catalyst has both excellent acidic water electrolysis oxygen evolution activity and long-term cycle stability, and can avoid excessive phase separation of Y element and excessive lattice distortion of other elements.

[0007] To achieve the above objectives, the present invention provides a method for preparing a doped and modulated ruthenium-iridium-based electrocatalytic oxygen evolution catalyst, comprising the following steps: S1. Preparation of mixed metal salt solution: Disperse ruthenium salt, iridium salt and doped metal salt in solvent by molar ratio, stir to obtain mixed metal salt solution; wherein, the doped metal salt is selected from one or more of yttrium salt Y, strontium salt Sr, potassium salt K, calcium salt Ca, magnesium salt Mg, scandium salt Sc, gallium salt Ga and aluminum salt Al; S2. Preparation of precursor mixture: The metal salt mixture solution obtained in S1 is added to the carrier precursor, and after grinding and homogenization, the precursor mixture is obtained. S3. The precursor mixture obtained in S2 is placed in a heat treatment device and heat-treated in an oxygen-containing atmosphere. After cooling to room temperature, a solid product is obtained. S4. Washing and drying: The solid product obtained in S3 is first acid-washed, then washed with deionized water until the washing solution is neutral, and then dried to obtain a metal element-doped ruthenium-iridium-based electrocatalytic oxygen evolution catalyst.

[0008] Preferably, in S1, the ruthenium salt is selected from one or two of ruthenium trichloride and ruthenium trichloride hydrate, the iridium salt is selected from one or two of iridium trichloride and iridium trichloride hydrate, and the yttrium salt is selected from one or two of yttrium chloride hexahydrate and yttrium nitrate.

[0009] Preferably, in S1, the solvent is ethanol to ensure the full dissolution and uniform dispersion of ruthenium salt, iridium salt, and doped metal salt, laying the foundation for the subsequent formation of a uniform ruthenium-iridium composite oxide.

[0010] Preferably, in S1, the molar ratio of the ruthenium salt, the iridium salt, and the yttrium salt is 0.6~0.8:0.1~0.3:0.05~0.15.

[0011] Preferably, in S1, the molar ratio of the ruthenium salt, the iridium salt, and the yttrium salt is 0.7~0.75:0.15~0.25:0.08~0.12.

[0012] The molar ratio of this yttrium salt is precisely controlled by adjusting the proportion of highly active sites of Ru, the lattice stabilizing effect of Ir, and the electronic regulation function of dopants, thereby achieving synergistic optimization of the three factors and maximizing the overall performance of the catalyst.

[0013] Preferably, in S1, the concentration of ruthenium in the metal salt mixed solution is 10~50 g / L, the concentration of iridium is 5~20 g / L, and the concentration of the dopant element corresponding to the doped metal salt is 2~10 g / L.

[0014] By precisely controlling the concentration, the molar fraction of subsequent doping elements in the ruthenium-iridium composite oxide is ensured to meet the design requirements, while also guaranteeing the uniform distribution of Ru and Ir.

[0015] Preferably, in S1, the concentration of ruthenium in the metal salt mixed solution is 20~40 g / L, the concentration of iridium is 8~15 g / L, and the concentration of the dopant element corresponding to the doped metal salt is 3~8 g / L.

[0016] The doping element is selected from at least one of Y (yttrium), Sr (strontium), K (potassium), Ca (calcium), Mg (magnesium), Sc (scandium), Ga (gallium), and Al (aluminum). These elements have suitable ionic radii and electronic properties, and can be precisely integrated into the ruthenium-iridium composite oxide lattice to form a synergistic effect with Ru and Ir, thereby optimizing electron transport efficiency and lattice stability. Among them, due to its unique ionic properties, Y element is prone to phase separation when the doping amount exceeds the standard, and its content needs to be controlled in a targeted manner.

[0017] The molar fraction of the dopant element in the ruthenium-iridium composite oxide is 0.05~0.15, and this content range is synergistically adapted to the characteristics of the selected dopant element and the proportion of the support. When the dopant element is Y: when the molar fraction is less than 0.05, its regulatory effect on the electronic and crystal structures of the ruthenium-iridium composite oxide is insufficient, and it cannot fully stimulate the catalytic activity of Ru and the structural stability of Ir, so the oxygen evolution activity of the catalyst cannot meet the requirements of high-efficiency catalysis; when the molar fraction is greater than 0.15, excess Y will destroy the lattice integrity of the ruthenium-iridium composite oxide, triggering the phase separation phenomenon of Ru-O phase and Ir-O phase, breaking the synergistic effect of Ru and Ir, resulting in a significant decrease in catalytic stability; When the doping element is any one of Sr, K, Ca, Mg, Sc, Ga, or Al: when the molar fraction is less than 0.05, there is also the problem of insufficient regulation and limited improvement in catalytic activity; when the molar fraction is greater than 0.15, although it will not cause obvious phase separation, it will lead to lattice distortion of ruthenium-iridium composite oxide, destroy the synergistic interaction sites of Ru and Ir, and reduce structural stability and catalytic cycle performance.

[0018] Preferably, in S2, the carrier precursor is a mixture of NH4NO3 and D-glucose, wherein the mass ratio of NH4NO3 to D-glucose is 0.6~1.0:1.

[0019] The mass ratio of the carrier precursor is synergistically matched with the selection and content of doping elements, playing a dispersing and supporting role in the preparation process. This can prevent metal ion agglomeration, ensure uniform distribution of Ru, Ir, and doping elements, and completely decompose and remove them during subsequent heat treatment, leaving no residue in the final catalyst.

[0020] Preferably, in S3, the heat treatment specifically includes: Heat to 400~600℃ at a rate of 5~10℃ / min and hold for 60~120min. The oxygen-containing atmosphere is specifically an air atmosphere.

[0021] Through heat treatment, the metal salt is transformed into a ruthenium-iridium composite oxide, and the dopant element is successfully incorporated into the crystal lattice, forming a stable synergistic structure with Ru and Ir. At the same time, the carrier precursor is completely decomposed and removed.

[0022] Preferably, in S4, the washing specifically includes: Wash the solid product 2-3 times with 0.5-2.0 mol / L hydrochloric acid or sulfuric acid, filter the solid product, and then wash it with deionized water. Repeat the washing until the pH of the washing solution is 6.5-7.5.

[0023] Preferably, in step S4, the drying specifically involves: Freeze-drying is employed, using liquid nitrogen in a freeze dryer at a temperature of -100 to -25°C, a drying pressure of 10 to 40 Pa, and a drying time of 1 to 5 days.

[0024] The present invention also provides a doped and regulated ruthenium-iridium-based electrocatalytic oxygen evolution catalyst, comprising a Y-doped Ru-Ir composite oxide active component, wherein the purity of the Y-doped Ru-Ir composite oxide is ≥99.9 wt%.

[0025] Glucose and ammonium nitrate form gases that evaporate in the air atmosphere. This purity of Y-doped Ru-Ir composite oxide has no residual support components, which can maximize the exposure of Ru-Ir-doped element synergistic active sites and avoid the interference of impurities on catalytic performance.

[0026] Preferably, the size of the nanoparticles is 2-3 nm.

[0027] Nanoparticles in this size range can maximize the exposure of Ru-Ir synergistic active sites while shortening charge transport pathways and improving catalytic kinetics.

[0028] Therefore, the present invention employs the above-mentioned doped and regulated ruthenium-iridium-based electrocatalytic oxygen evolution catalyst and its preparation method, which has the following beneficial effects: The catalyst of this invention exhibits high purity and excellent performance through the synergistic effect of three factors: selection of doping elements (Y, Sr, K, Ca, Mg, Sc, Ga, Al), control of doping content (mole fraction 0.05~0.15), and support ratio (NH4NO3 to D-glucose mass ratio 0.6~1.0:1). The ionic characteristics of the doping elements are well-suited to the ruthenium-iridium composite system and the support ratio—the chloride salts of Y, Sr, K, Ca, Mg, Sc, Ga, and Al exhibit good solubility and can be uniformly dispersed with ruthenium and iridium salts in the same solvent system, and their ionic radii are similar to those of Ru. 4+ Ir 4+ With good compatibility, it can be smoothly integrated into the ruthenium-iridium composite oxide lattice under the support ratio of 0.6 to 1.0:1. At the same time, the doping content range of 0.05 to 0.15 is synergistic with the support ratio, which can avoid problems such as phase separation of Y element and lattice distortion of other elements. Only by changing the type of doped metal salt, while keeping the type and ratio of ruthenium and iridium salts, solvent type, ultrasonic grinding parameters, heat treatment conditions, washing and drying parameters and other preparation process parameters unchanged, the controllable preparation of ruthenium-iridium based electrocatalytic oxygen evolution catalysts with different doping elements can be achieved. It has both abundant active sites and rapid charge transport capability, ensuring that the catalysts corresponding to different doping elements can maintain a stable crystal structure and excellent oxygen evolution catalytic performance.

[0029] This invention offers flexibility, overcoming the limitations of single-parameter control in existing technologies. It allows for the flexible preparation of ruthenium-iridium-based catalysts with multiple element doping levels simply by replacing the doped metal salt. This fully leverages the regulatory advantages of different doping elements on the ruthenium-iridium composite system, adapting to the diverse catalytic performance requirements of different application scenarios. Specifically, the Y-element-controlled ruthenium-iridium-based electrocatalytic oxygen evolution catalyst meets the engineering application requirements of 3 A / cm². 2 Far exceeding the existing 1A / cm 2 This provides a systematic solution for the diversified design and optimization of catalysts.

[0030] This invention features consistency and reproducibility. By specifically differentiating the content thresholds of Y with other doping elements, the molar fraction of doping is strictly controlled within the range of 0.05 to 0.15. At the same time, the ratio of support is optimized to 0.6 to 1.0:1, achieving a synergistic effect of "high activity of Ru + high stability of Ir + electronic regulation of doping elements + dispersion support of the support". The fixed preparation process parameters can ensure the consistency and reproducibility of the catalyst's performance (both high oxygen evolution activity and long cycle stability).

[0031] The preparation process of this invention is simple and efficient, adopting a simple process route of "mixing-dispersion-heat treatment-washing and drying". It does not require complex equipment or harsh reaction conditions. The carrier precursor can be completely removed during the heat treatment process without the need for additional removal steps. The preparation cycle is short, the operation is convenient, the raw materials are readily available, and the key parameters are highly controllable, making it suitable for large-scale industrial production.

[0032] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0033] Figure 1 These are X-ray diffraction (XRD) patterns of Examples 1, 5-7 of the present invention, which describe a doped and regulated ruthenium-iridium-based electrocatalytic oxygen evolution catalyst and its preparation method. Figure 2 This is a transmission electron microscope (TEM) image of Example 1 of the present invention, which describes a doped and regulated ruthenium-iridium-based electrocatalytic oxygen evolution catalyst and its preparation method. Figure 3 This is an atomic force microscope (AFM) image of Example 1 of the present invention, which describes a doped and regulated ruthenium-iridium-based electrocatalytic oxygen evolution catalyst and its preparation method. In the image, a is a surface morphology image and b is a height profile image. Figure 4 This is a PEMWE stability test graph of Example 1 of the present invention, which describes a doped and regulated ruthenium-iridium-based electrocatalytic oxygen evolution catalyst and its preparation method. Figure 5 This invention relates to a doped and regulated ruthenium-iridium-based electrocatalytic oxygen evolution catalyst and its preparation method, as described in Examples 1-4 of the present invention, at a 10 mA cm⁻¹. -2 Current density test graphs, where a is the scanning volt-ampere curve and b is the overpotential diagram; Figure 6 These are XRD patterns of Examples 1-4 of the present invention: a doped and regulated ruthenium-iridium-based electrocatalytic oxygen evolution catalyst and its preparation method. Figure 7 These are XRD patterns of various element dopings in the embodiments and comparative examples of the present invention, namely, a is Example 8, b is Example 9, c is Comparative Example 1, and d is Example 10. Figure 8This is a performance comparison chart of Examples 1, 5-7 and Comparative Example 1 of the present invention, which describes a doped and regulated ruthenium-iridium-based electrocatalytic oxygen evolution catalyst and its preparation method. In the figure, a is the polarization curve and b is the overpotential bar chart. Figure 9 This is a comparison of the polarization curves of Example 1 and Comparative Examples 1-2 of the present invention, which describes a doped and regulated ruthenium-iridium-based electrocatalytic oxygen evolution catalyst and its preparation method. Detailed Implementation

[0034] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0035] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0037] Example 1 A doped and regulated ruthenium-iridium-based electrocatalytic oxygen evolution catalyst, specifically a yttrium-doped and regulated ruthenium-iridium-based electrocatalytic oxygen evolution catalyst, is prepared as follows: 1. Preparation of metal salt mixed solution: Weigh 35 μmol of ruthenium trichloride (RuCl3), 10 μmol of iridium trichloride (IrCl3), and 5 μmol of yttrium chloride hexahydrate (YCl3·6H2O) according to the molar ratio of Ru, Ir, and Y of 0.7:0.2:0.1. Disperse them in 10 mL of ethanol and stir at room temperature for 40 min until completely dissolved to obtain a metal salt mixed solution. The concentration of Ru is 353.75 mg / L, the concentration of Ir is 192.22 mg / L, and the concentration of Y is 44.46 mg / L, ensuring that Ru and Ir are uniformly dispersed and that the Y element is accurately proportioned.

[0038] 2. Preparation of precursor mixture: Mix 0.8g NH4NO3 and 1g D-glucose evenly (mass ratio of NH4NO3 to D-glucose 0.8:1), then add metal salt mixed solution, and then transfer to a mortar and grind for 25min until homogenized to obtain precursor mixture. Ensure that the metal ions and the support precursor are fully mixed to avoid agglomeration.

[0039] 3. Heat treatment: The precursor mixture is placed in an alumina crucible and then placed in a muffle furnace. The temperature is increased to 500°C at a heating rate of 8°C / min under an air atmosphere and held for 100 min. After the heat treatment, the mixture is naturally cooled to room temperature to obtain a solid product. During this process, the metal salt is converted into Y-doped ruthenium-iridium composite oxide and the support precursor is completely decomposed.

[0040] 4. Washing and drying: The solid product was washed three times with 1.0 mol / L sulfuric acid, filtered, and then dispersed in 50 mL of deionized water. After standing, the supernatant was removed by decantation. The washing was repeated three times until the pH of the washing solution was 7.0. Subsequently, the solid product was dried in a freeze dryer at -60℃ and 25 Pa for 48 h to obtain the Y-doped ruthenium-iridium-based electrocatalytic oxygen evolution catalyst.

[0041] Example 2 A doped and regulated ruthenium-iridium-based electrocatalytic oxygen evolution catalyst, specifically an Sr-doped and regulated ruthenium-iridium-based electrocatalytic oxygen evolution catalyst, is prepared as follows: 1. Preparation of metal salt mixed solution: Weigh 35 μmol of ruthenium trichloride (RuCl3), 10 μmol of iridium trichloride (IrCl3), and 5 μmol of strontium chloride (SrCl2) according to the molar ratio of Ru, Ir, and Sr of 0.7:0.2:0.1. Disperse them in 10 mL of ethanol and stir at room temperature for 35 min until completely dissolved to obtain a metal salt mixed solution. The concentration of Ru is 353.75 mg / L, the concentration of Ir is 192.22 mg / L, and the concentration of Sr is 43.81 mg / L to ensure the synergistic ratio of Ru and Ir and the precise doping of Sr.

[0042] 2. Preparation of precursor mixture: Mix 0.7g NH4NO3 and 1g D-glucose evenly (mass ratio of NH4NO3 to D-glucose 0.7:1), then add metal salt mixed solution, and then transfer to a mortar and grind for 25min until homogenized to obtain precursor mixture.

[0043] 3. Heat treatment: The precursor mixture was placed in an alumina crucible and placed in a muffle furnace. The temperature was increased to 480°C at a heating rate of 7°C / min under an air atmosphere and held for 110 min. After the heat treatment, the mixture was allowed to cool naturally to room temperature to obtain a solid product.

[0044] 4. Washing and drying: The solid product was washed three times with 1.0 mol / L sulfuric acid, filtered, and then dispersed in 50 mL of deionized water. After standing, the supernatant was removed by decantation. The washing was repeated three times until the pH of the washing solution was 7.0. Subsequently, the solid product was dried in a freeze dryer at -60℃ and 25 Pa for 48 h to obtain Sr-doped ruthenium-iridium-based electrocatalytic oxygen evolution catalyst.

[0045] Example 3 A doped and regulated ruthenium-iridium-based electrocatalytic oxygen evolution catalyst, specifically a Sc-doped and regulated ruthenium-iridium-based electrocatalytic oxygen evolution catalyst, is prepared as follows: 1. Preparation of mixed metal salt solution: 35 μmol of ruthenium trichloride (RuCl3), 10 μmol of iridium trichloride (IrCl3), and 5 μmol of scandium chloride (ScCl3) were weighed according to the molar ratio of Ru, Ir, and Sc of 0.7:0.2:0.1. The mixture was dispersed in 10 mL of ethanol and stirred at room temperature for 45 min until completely dissolved to obtain a mixed metal salt solution. The concentration of Ru was 353.75 g / L, the concentration of Ir was 192.22 mg / L, and the concentration of Sc was 22.48 mg / L, to enhance the stabilizing effect of Ir and the regulatory effect of Sc.

[0046] 2. Preparation of precursor mixture: Mix 0.9g NH4NO3 and 1g D-glucose evenly (mass ratio of NH4NO3 to D-glucose 0.9:1), then add metal salt mixed solution, and then transfer to a mortar and grind for 25min until homogenized to obtain precursor mixture.

[0047] 3. Heat treatment: The precursor mixture was placed in an alumina crucible and then placed in a muffle furnace. The temperature was increased to 520°C at a heating rate of 9°C / min under an air atmosphere and held for 90 min. After the heat treatment, the mixture was allowed to cool naturally to room temperature to obtain a solid product.

[0048] 4. Washing and drying: The solid product was washed three times with 1.0 mol / L sulfuric acid, filtered, and then dispersed in 50 mL of deionized water. After standing, the supernatant was removed by decantation. The washing was repeated three times until the pH of the washing solution was 7.0. Subsequently, the solid product was dried in a freeze dryer at -60℃ and 25 Pa for 48 h to obtain Sc-doped ruthenium-iridium-based electrocatalytic oxygen evolution catalyst.

[0049] Example 4 A doped and regulated ruthenium-iridium-based electrocatalytic oxygen evolution catalyst, specifically an Al-doped and regulated ruthenium-iridium-based electrocatalytic oxygen evolution catalyst, is prepared as follows: 1. Preparation of metal salt mixed solution: 35 μmol of ruthenium trichloride (RuCl3), 10 μmol of iridium trichloride (IrCl3), and 5 μmol of aluminum chloride (AlCl3) were weighed according to the molar ratio of Ru, Ir, and Al of 0.7:0.2:0.1. The mixture was dispersed in 10 mL of ethanol and stirred at room temperature for 30 min until completely dissolved to obtain a metal salt mixed solution. The concentration of Ru was 353.75 mg / L, the concentration of Ir was 192.22 mg / L, and the concentration of Al was 13.49 mg / L. The synergistic ratio of Ru, Ir, and Al was optimized.

[0050] 2. Preparation of precursor mixture: Mix 0.6g NH4NO3 and 1g D-glucose evenly (mass ratio of NH4NO3 to D-glucose 0.6:1), then add metal salt mixed solution, and then transfer to a mortar and grind for 25min until homogenized to obtain precursor mixture.

[0051] 3. Heat treatment: The precursor mixture was placed in an alumina crucible and placed in a muffle furnace. The temperature was increased to 460°C at a heating rate of 6°C / min under an air atmosphere and held for 115 min. After the heat treatment, the mixture was allowed to cool naturally to room temperature to obtain a solid product.

[0052] 4. Washing and drying: The solid product was washed three times with 1.0 mol / L sulfuric acid, filtered, and then dispersed in 50 mL of deionized water. After standing, the supernatant was removed by decantation. The washing was repeated three times until the pH of the washing solution was 7.0. Subsequently, the solid product was dried in a freeze dryer at -60℃ and 25 Pa for 48 h to obtain Al-doped ruthenium-iridium-based electrocatalytic oxygen evolution catalyst.

[0053] Example 5 A doped and regulated ruthenium-iridium-based electrocatalytic oxygen evolution catalyst, specifically a Y-doped and regulated ruthenium-iridium-based electrocatalytic oxygen evolution catalyst, differs from that in Example 1 in that the molar ratio of Ru, Ir, and Y is adjusted to 0.75:0.2:0.05.

[0054] The remaining steps are exactly the same as in Example 1.

[0055] Example 6 A doped and regulated ruthenium-iridium-based electrocatalytic oxygen evolution catalyst, specifically a Y-doped and regulated ruthenium-iridium-based electrocatalytic oxygen evolution catalyst, differs from that in Example 1 in that the molar ratio of Ru, Ir, and Y is adjusted to 0.65:0.2:0.15.

[0056] The remaining steps are exactly the same as in Example 1.

[0057] Example 7 A doped and regulated ruthenium-iridium-based electrocatalytic oxygen evolution catalyst, specifically a Y-doped and regulated ruthenium-iridium-based electrocatalytic oxygen evolution catalyst, differs from the preparation method in Example 1 in that the molar ratio of Ru, Ir, and Y is adjusted to 0.6:0.2:0.2.

[0058] The remaining steps are exactly the same as in Example 1.

[0059] Example 8 A doped and regulated ruthenium-iridium-based electrocatalytic oxygen evolution catalyst, specifically a K-doped and regulated ruthenium-iridium-based electrocatalytic oxygen evolution catalyst, differs in its preparation method from that of Example 1 in that: Preparation of the metal salt mixed solution: Weigh 35 μmol of ruthenium trichloride (RuCl3), 10 μmol of iridium trichloride (IrCl3), and 5 μmol of potassium chloride (KCl) according to the molar ratio of Ru, Ir, and K of 0.7:0.2:0.1. Disperse them in 10 mL of ethanol and stir at room temperature for 40 min until completely dissolved to obtain the metal salt mixed solution; wherein, the concentration of Ru is 353.75 mg / L, the concentration of Ir is 192.22 mg / L, and the concentration of K is 19.55 mg / L.

[0060] The remaining steps are exactly the same as in Example 1.

[0061] Example 9 A doped and regulated ruthenium-iridium-based electrocatalytic oxygen evolution catalyst, specifically a Mg-doped and regulated ruthenium-iridium-based electrocatalytic oxygen evolution catalyst, differs in its preparation method from that of Example 1 in that: Preparation of the metal salt mixed solution: Weigh 35 μmol of ruthenium trichloride (RuCl3), 10 μmol of iridium trichloride (IrCl3), and 5 μmol of potassium chloride (MgCl2) according to the molar ratio of Ru, Ir, and Mg of 0.7:0.2:0.1. Disperse them in 10 mL of ethanol and stir at room temperature for 40 min until completely dissolved to obtain the metal salt mixed solution; wherein, the concentration of Ru is 353.75 mg / L, the concentration of Ir is 192.22 mg / L, and the concentration of Mg is 12.15 mg / L.

[0062] The remaining steps are exactly the same as in Example 1.

[0063] Example 10 A doped and regulated ruthenium-iridium-based electrocatalytic oxygen evolution catalyst, specifically a Ca-doped and regulated ruthenium-iridium-based electrocatalytic oxygen evolution catalyst, differs in its preparation method from that of Example 1 in that: Preparation of the metal salt mixed solution: Weigh 35 μmol of ruthenium trichloride (RuCl3), 10 μmol of iridium trichloride (IrCl3), and 5 μmol of calcium chloride (CaCl2) according to the molar ratio of Ru, Ir, and Ca of 0.7:0.2:0.1. Disperse them in 10 mL of ethanol and stir at room temperature for 40 min until completely dissolved to obtain the metal salt mixed solution; wherein, the concentration of Ru is 353.75 mg / L, the concentration of Ir is 192.22 mg / L, and the concentration of Ca is 20.04 mg / L.

[0064] The remaining steps are exactly the same as in Example 1.

[0065] Comparative Example 1 A ruthenium-iridium-based electrocatalytic oxygen evolution catalyst, with a Ru:Ir molar ratio of 0.8:0.2, differs in its preparation method from that of Example 1 in that: 1. Preparation of mixed metal salt solution: Weigh RuCl3 and IrCl3·3H2O according to the molar ratio of Ru to Ir of 0.8:0.2, disperse them in 10 mL of ethanol, and stir at room temperature for 35 min until completely dissolved to obtain a mixed metal salt solution.

[0066] The remaining steps are exactly the same as in Example 1.

[0067] Comparative Example 2 A commercial ruthenium oxide electrocatalytic oxygen evolution catalyst, sourced from Zhongke Kechuang New Energy Technology Co., Ltd., Ningbo City, Zhejiang Province.

[0068] Test 1. Structural analysis was performed on the Y-doped ruthenium-iridium based catalysts prepared in Examples 1 and 5-7. X-ray diffraction (XRD) was used to analyze the structures. Figure 1 As shown, the transmission electron microscope (TEM) of Example 1 is as follows: Figure 2 As shown, the atomic force microscope (AFM) of Example 1 is as follows: Figure 3 As shown.

[0069] Depend on Figure 1 It can be seen that the catalyst has a typical ruthenium-iridium composite oxide crystal structure with no obvious impurity peaks or phase separation peaks, proving that the Y element was successfully integrated into the crystal lattice under the protection content and support ratio, and that the synergistic structure of Ru and Ir is stable.

[0070] Depend on Figure 2 It can be seen that the catalyst exists in the form of nanoparticles with uniform particle size of about 2~3nm and good dispersibility, proving that the proportion of support is reasonable and no metal ion agglomeration occurs.

[0071] Depend on Figure 3 It can be seen that the thickness of the catalyst nanosheets is about 1~3nm, proving that they are ultrathin nanosheets.

[0072] Furthermore, if the molar fraction is below 0.05, its regulatory effect on the electronic and crystal structures of the ruthenium-iridium composite oxide is insufficient, failing to fully stimulate the catalytic activity of Ru and the structural stability of Ir, thus making the oxygen evolution activity of the catalyst unable to meet the requirements for high-efficiency catalysis. When the molar fraction is above 0.15, excess Y will destroy the lattice integrity of the ruthenium-iridium composite oxide, inducing phase separation of Ru-O and Ir-O phases, breaking the synergistic effect of Ru and Ir, and thus leading to a significant decrease in catalytic stability. Similarly, when the doping element is any one of Sr, K, Ca, Mg, Sc, Ga, or Al: when the molar fraction is below 0.05, the same problem of insufficient regulation and limited improvement in catalytic activity exists; when the molar fraction is above 0.15, although it will not induce obvious phase separation, it will cause lattice distortion of the ruthenium-iridium composite oxide, destroying the synergistic interaction sites of Ru and Ir, and reducing structural stability and catalytic cycle performance.

[0073] 2. The Y-doped ruthenium-iridium based catalyst prepared in Example 1 was subjected to PEMWE stability testing. The electrolyte was ultrapure water, 3 A·cm⁻¹. -2 After 2800 hours of continuous operation at current density, the results are as follows: Figure 4 As shown.

[0074] Depend on Figure 4 It can be seen that the overpotential of the catalyst does not decrease significantly, indicating excellent catalytic stability, which proves that the synergistic effect of ruthenium-iridium synergy, Y doping regulation and support amount optimization is effective.

[0075] 3. Electrochemical tests were performed on the ruthenium-iridium based catalysts with different doping elements prepared in Examples 1-4. The electrolyte was a 0.1 M HClO4 aqueous solution, and the electrochemical temperature was 10 mA cm⁻¹. -2 The scanning voltammetric curve at current density is as follows: Figure 5 As shown in a, at 10 mAcm -2 The overpotential under current density is illustrated as follows: Figure 5 As shown in b in the figure.

[0076] Depend on Figure 5 It can be seen that some of the catalysts exhibit excellent electrocatalytic activity, among which the catalyst with Y element introduced in Example 1 shows the best electrocatalytic activity, meeting the engineering application requirement of 3A / cm. 2 standard.

[0077] 4. Structural analysis was performed on the ruthenium-iridium based catalysts with different doping element regulation prepared in Examples 1-4, 8-10, and Comparative Example 1. XRD patterns are shown below. Figure 6 and Figure 7 As shown.

[0078] Depend on Figure 6 and Figure 7It can be seen that the catalyst of the shown embodiment has a typical ruthenium-iridium composite oxide crystal structure with no obvious impurity peaks or phase separation peaks, proving that the elements were successfully incorporated into the crystal lattice under the protection content and support ratio, and that the synergistic structure of Ru and Ir is stable.

[0079] 5. Performance analysis was performed on the Y-doped ruthenium-iridium based catalysts prepared in Examples 1, 5-7, the ruthenium-iridium based electrocatalytic oxygen evolution catalyst prepared in Comparative Example 1, and the ruthenium oxide electrocatalytic oxygen evolution catalyst prepared in Comparative Example 2. The results are as follows: Figures 8-9 As shown.

[0080] Depend on Figure 8 It can be seen that the Y-doped ruthenium-iridium based catalyst of Example 1 meets the engineering application requirements of 3 A / cm. 2 .

[0081] Depend on Figure 9 It can be seen that the engineering application performance of commercial catalysts is 1 A / cm. 2 The Y-element-regulated ruthenium-iridium-based electrocatalytic oxygen evolution catalyst far exceeds the standards of existing commercial catalysts.

[0082] Therefore, the present invention employs the above-mentioned doped ruthenium-iridium-based electrocatalytic oxygen evolution catalyst and its preparation method. The process is simple and highly universal. Multiple element doping can be achieved simply by replacing the doping metal salt. The resulting catalyst has both excellent acidic water electrolysis oxygen evolution activity and long-term cycle stability, and can avoid excessive phase separation of Y element and excessive lattice distortion of other elements.

[0083] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for preparing a doped and regulated ruthenium-iridium-based electrocatalytic oxygen evolution catalyst, characterized in that, Includes the following steps: S1. Preparation of mixed metal salt solution: Disperse ruthenium salt, iridium salt and doped metal salt in solvent by molar ratio, stir to obtain mixed metal salt solution; wherein, the doped metal salt is selected from one or more of yttrium salt, strontium salt, potassium salt, calcium salt, magnesium salt, scandium salt, gallium salt and aluminum salt; S2. Preparation of precursor mixture: The metal salt mixture solution obtained in S1 is added to the carrier precursor, and after grinding and homogenization, the precursor mixture is obtained. S3. The precursor mixture obtained in S2 is placed in a heat treatment device and heat-treated in an oxygen-containing atmosphere. After cooling to room temperature, a solid product is obtained. S4. Washing and drying: The solid product obtained in S3 is first acid-washed, then washed with deionized water until the washing solution is neutral, and then dried to obtain a metal element-doped ruthenium-iridium-based electrocatalytic oxygen evolution catalyst.

2. The method for preparing a doped and regulated ruthenium-iridium-based electrocatalytic oxygen evolution catalyst according to claim 1, characterized in that, In S1, the ruthenium salt is selected from one or two of ruthenium trichloride and ruthenium trichloride hydrate; the iridium salt is selected from one or two of iridium trichloride and iridium trichloride hydrate; and the yttrium salt is selected from one or two of yttrium chloride hexahydrate and yttrium nitrate.

3. The method for preparing a doped and regulated ruthenium-iridium-based electrocatalytic oxygen evolution catalyst according to claim 2, characterized in that, In S1, the solvent is specifically ethanol.

4. The method for preparing a doped and regulated ruthenium-iridium-based electrocatalytic oxygen evolution catalyst according to claim 2, characterized in that, In S1, the molar ratio of the ruthenium salt, the iridium salt, and the yttrium salt is 0.6~0.8:0.1~0.3:0.05~0.

15.

5. The method for preparing a doped and regulated ruthenium-iridium-based electrocatalytic oxygen evolution catalyst according to claim 1, characterized in that, In S1, the concentration of ruthenium in the metal salt mixed solution is 10~50 g / L, the concentration of iridium is 5~20 g / L, and the concentration of the dopant element corresponding to the doped metal salt is 2~10 g / L.

6. The method for preparing a doped and regulated ruthenium-iridium-based electrocatalytic oxygen evolution catalyst according to claim 1, characterized in that, In S2, the carrier precursor is a mixture of NH4NO3 and D-glucose, wherein the mass ratio of NH4NO3 to D-glucose is 0.6~1.0:

1.

7. The method for preparing a doped and regulated ruthenium-iridium-based electrocatalytic oxygen evolution catalyst according to claim 1, characterized in that, In S3, the heat treatment specifically includes: Heat to 400~600℃ at a rate of 5~10℃ / min and hold for 60~120min. The oxygen-containing atmosphere is specifically an air atmosphere.

8. The method for preparing a doped and regulated ruthenium-iridium-based electrocatalytic oxygen evolution catalyst according to claim 1, characterized in that, In S4, the washing process specifically includes: Wash the solid product 2-3 times with 0.5-2.0 mol / L hydrochloric acid or sulfuric acid, filter the solid product, and then wash it with deionized water. Repeat the washing until the pH of the washing solution is 6.5-7.

5.

9. The method for preparing a doped and regulated ruthenium-iridium-based electrocatalytic oxygen evolution catalyst according to claim 1, characterized in that, In S4, the drying process specifically involves: Freeze drying is used, with a drying temperature of -100 to -25℃, a drying pressure of 10 to 40 Pa, and a drying time of 1 to 5 days.

10. A doped ruthenium-iridium-based electrocatalytic oxygen evolution catalyst prepared by the method described in any one of claims 1 to 9, characterized in that, The active component includes a Y-doped Ru-Ir composite oxide, wherein the purity of the Y-doped Ru-Ir composite oxide is ≥99.9 wt%.

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