Preparation method and application of metal lanthanum doped coupling oxygen vacancy ruthenium oxide based monolithic electrode

Abstract

The application discloses a preparation method and application of a metal lanthanum doped coupling oxygen vacancy ruthenium oxide based monolithic electrode and belongs to the technical field of electrochemical materials. First, impurities on the surface of a metal conductive substrate or a carbon substrate are removed, then an aqueous solution containing a ruthenium salt and a lanthanum salt is prepared, the prepared solution is drop-coated on the metal conductive substrate or the carbon substrate under infrared lamp irradiation, drying is performed, and the prepared solution is calcined at 300-500 DEG C for 1-5 h in an oxidizing atmosphere; after cooling, the metal lanthanum doped coupling oxygen vacancy ruthenium oxide based monolithic electrode is obtained. The preparation method can prepare a non-supported monolithic ruthenium oxide based catalyst, the method has wide universality, the conditions are easy to control, and the method is easy to operate. The metal lanthanum doped coupling oxygen vacancy ruthenium oxide based monolithic electrode prepared by the method can be used as an anode material for an acid oxygen evolution reaction and has excellent performance and wide application prospect.

Description

A method for fabricating and applying a monolithic ruthenium oxide-based electrode with lanthanum doping and oxygen vacancies. Technical Field

[0001] This invention belongs to the field of electrochemical materials technology, and more specifically, it relates to a method for preparing and applying an acid-resistant lanthanum-doped ruthenium oxide-based monolithic electrode coupled with oxygen vacancies. Background Technology

[0002] The overuse of fossil fuels not only leads to resource depletion but also causes serious environmental problems such as the greenhouse effect and air pollution, urgently requiring renewable energy storage and conversion technologies. Hydrogen (H2) is one of the most promising new energy sources and an optimal energy carrier and an essential choice for future low-carbon energy (Peter et al., ACS Energy Lett., 2023, 8, 3330). Polymer electrolyte membrane electrolyzers (PEMWEs) powered by renewable electricity are considered a promising green hydrogen production technology. However, the oxygen evolution reaction (OER) at the anode is one of the main obstacles to the practical application of PEMWEs. The highly acidic environment and extremely oxidizing working conditions make the development of highly active and stable OER electrocatalysts extremely challenging (Wang et al., ACS Cat., 2023, 13, 8670; Chong et al., Science, 2023, 380, 609). Ruthenium oxide (Ru)-based materials, as acidic OER catalysts, possess the advantages of high activity and the lowest price among the noble metal family, but their long-term durability is far from satisfactory. To improve the stability of Ruthenium oxide-based catalysts, a "metal doping" strategy has been proposed. Metal doping can enhance the covalent nature of the metal-oxygen bond, accelerating electron transfer in the OER process. Simultaneously, the doped metal modulates the electronic structure of Ruthenium oxide, preventing further oxidation and dissolution (Qin et al., Nano Lett., 2021, 21, 5774). This strategy opens up possibilities for the catalytic application of Ruthenium oxide in harsh environments and provides a new approach for developing highly active and stable acidic water electrolysis catalysts.

[0003] Studies have shown that controllable vacancy defects can increase the number and catalytic activity of surface active sites, potentially improving the activity and stability of acidic OER catalysts. Current research on "vacancy defects" is limited to the modification of nanocatalysts, resulting in ruthenium oxide-based catalysts that are powder materials requiring further fabrication into supported electrodes to participate in the reaction (Wang et al., Nat. Commun., 2023, 14, 1412). The fabrication process of supported electrodes has the following drawbacks: firstly, the use of substrates and binders increases process costs; secondly, under conditions of strong stirring and high gas flow, the catalyst may detach from the substrate during prolonged testing, leading to a decrease in the activity and stability of acidic OER. More importantly, the limited catalyst loading and active sites restrict the catalytic performance of the electrode per unit area for water electrolysis. Therefore, developing monolithic ruthenium oxide catalytic electrodes is essential for advancing the development of the oxygen evolution reaction in acidic water electrolysis. Currently, the fabrication of monolithic catalytic electrodes remains challenging, and no research has been reported on the use of monolithic ruthenium oxide catalytic electrodes with metal doping coupled with oxygen vacancies in water electrolysis technology. Summary of the Invention

[0004] Therefore, the purpose of this invention is to provide a method for preparing a monolithic ruthenium oxide-based catalytic electrode with lanthanum-doped metal and coupled oxygen vacancies for the acidic water electrolysis oxygen evolution reaction, and its application. This invention involves simultaneously drop-coating ruthenium salt and lanthanide metal salt solutions onto a titanium mesh surface, followed by calcination in air after infrared lamp irradiation to obtain a monolithic lanthanum-doped ruthenium oxide electrode material. This method is simple to operate and easy to scale up. The prepared self-supporting electrode material exhibits excellent electrocatalytic performance as an anode material for the acidic water electrolysis oxygen evolution reaction, and has broad application prospects.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows:

[0006] This invention provides a method for preparing a monolithic ruthenium oxide-based electrode doped with lanthanum and coupled with oxygen vacancies, comprising the following steps:

[0007] (1) Remove impurities from the surface of a metal conductive substrate or a carbon substrate;

[0008] (2) An aqueous solution containing ruthenium salt and lanthanum salt;

[0009] (3) Under infrared lamp irradiation, drop-coat the solution prepared in step (2) onto the surface of a metal conductive substrate or carbon substrate and dry it;

[0010] (4) The substrate precursor obtained in step (3) is calcined at 300-500°C for 1-5 hours in an oxidizing atmosphere to oxidize the ruthenium salt on the substrate. Ruthenium oxide with oxygen vacancies is grown in situ on the substrate surface. After cooling, a monolithic ruthenium oxide electrode with metal doping coupled with oxygen vacancies is obtained.

[0011] Based on the above technical solution, further, in step (1), impurities on the surface of the metal conductive substrate or carbon substrate are removed using either of the following two methods:

[0012] 1. Solution cleaning method: Place the substrate in deionized water, hydrochloric acid solution, acetone, and ethanol, and clean it by ultrasonication or stirring. Finally, clean it again with deionized water, and blow dry or dry it for later use. The order of deionized water, hydrochloric acid solution, acetone, and ethanol is not limited.

[0013] II. Hydrogen reduction method: The substrate is reduced and purged in a reducing atmosphere of hydrogen or an inert gas containing hydrogen at 100-300℃ for more than 1 hour, and finally cooled to room temperature and taken out for use.

[0014] Based on the above technical solution, further, in step (1), the carbon substrate is one of carbon paper, carbon cloth, or carbon felt; the metal conductive substrate is one of titanium mesh or titanium foam; the area of ​​the carbon substrate or the metal conductive substrate is 1 to 100 cm². 2 .

[0015] Based on the above technical solution, further, in step (2), the ruthenium salt is one of carbonyl ruthenium, ruthenium chloride or ruthenium acetylacetonate; the concentration of the ruthenium salt is 0.01 mol / L to 0.05 mol / L, the concentration of the lanthanum salt is 3 mmol / L to 50 mmol / L; the solvent is one of water or ethanol.

[0016] Based on the above technical solution, further, in step (3), the droplet amount on the substrate surface is 100-400 μL / cm. 2 .

[0017] Based on the above technical solution, further, the oxidizing atmosphere mentioned in step (4) is either air or oxygen; the heating process is as follows: the temperature is increased to 300-500℃ at a heating rate of 5-10℃ / min, and the constant temperature time is 2-4h.

[0018] Another aspect of the present invention provides a monolithic lanthanum-doped ruthenium oxide-based electrode with oxygen vacancy coupling obtained by the above-described preparation method, wherein the monolithic electrode has a porous structure.

[0019] Another aspect of the present invention provides the application of the above-mentioned monolithic ruthenium oxide-based lanthanum-doped metal coupled with oxygen vacancy in acidic electrocatalytic water splitting reaction, which serves as an anode material for efficient water electrolysis and oxygen evolution, and exhibits long-term stability under strong acid and high current conditions.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] 1. The preparation method of the present invention can prepare an acid-resistant unloaded monolithic electrode. This method has wide applicability, simple conditions, and is easy to operate.

[0022] 2. The monolithic ruthenium oxide electrode with metal doping coupled to oxygen vacancies prepared by this invention can control the type of doped metal, the content of oxygen vacancies, and the conductive substrate, and can be adjusted according to different needs of catalytic production.

[0023] 3. The monolithic ruthenium oxide electrode with metal doping coupled oxygen vacancies prepared by this invention exhibits structural stability, excellent catalytic performance, and good durability in strong acid, strong alkali, and highly corrosive environments.

[0024] 4. The monolithic ruthenium oxide electrode with metal doping coupled oxygen vacancies prepared by the present invention has the advantages of eliminating the need for binders, saving production costs, simplifying electrode processing technology, and avoiding the problems of powder shedding and electrode deactivation in practical applications compared with powder-loaded electrodes. Attached Figure Description

[0025] Figure 1 is a scanning electron microscope image of the monolithic ruthenium oxide electrode with titanium mesh as substrate and lanthanum doping coupled with oxygen vacancies in Example 1. The magnifications of a, b, c, and d are 110x, 500x, 1000x, and 24000x, respectively.

[0026] Figure 2 shows the appearance of the large-sized monolithic ruthenium oxide electrode with metal doping coupled oxygen vacancies in Example 2, which measures 10*10cm.

[0027] Figure 3 shows the performance of Examples 1, 3-6 and commercial RuO2 acidic water electrolysis in the anodic oxygen evolution reaction;

[0028] Figure 4 shows the performance of the anodic oxygen evolution reaction in Examples 1, 7-9 and commercial RuO2 acidic water electrolysis;

[0029] Figure 5 shows the EPR diagrams for Examples 1, 7, 8, and 9;

[0030] Figure 6 shows the performance of the ruthenium oxide-based monolithic electrode of Example 10 in the anodic oxygen evolution reaction of acidic water electrolysis.

[0031] Figure 7 shows the performance of the ruthenium oxide-based monolithic electrode of Example 11 in the anodic oxygen evolution reaction of acidic water electrolysis.

[0032] Figure 8 shows the performance of the ruthenium oxide-based monolithic electrode of Example 12 in the anodic oxygen evolution reaction of acidic water electrolysis.

[0033] Figure 9 shows the performance of the ruthenium oxide-based monolithic electrode of Example 13 in the anodic oxygen evolution reaction of acidic water electrolysis.

[0034] Figure 10 shows the ruthenium oxide-based monolithic electrode of Example 1 under strong acid (0.5 M H2SO4) and high current (100 mA / cm²). -2 The long-term stability performance diagram of ). Detailed Implementation

[0035] The entire material preparation process is described in detail below through examples, but the scope of the claims of this invention is not limited to these examples. Furthermore, the examples only provide some conditions for achieving this objective, and do not imply that these conditions must be met to achieve this objective.

[0036] Unless otherwise specified, the materials used in the embodiments of the present invention can be obtained commercially or prepared according to conventional methods known to those skilled in the art.

[0037] The products in this embodiment were detected using the following instruments and methods:

[0038] The morphology of the products of Examples 1-12 was characterized using scanning electron microscopy (SEM) and transmission electron microscopy (TEM);

[0039] Vacancy extent maps of Examples 1, 7-9 were characterized using electron paramagnetic resonance (EPR);

[0040] The performance of the monolithic ruthenium oxide electrode with metal doped and oxygen vacancies prepared in Examples 1-13 in the acidic water electrolysis oxygen evolution reaction system was determined.

[0041] Examples 1-10 are examples of modulating the conductive substrate type and calcination temperature of the monolithic ruthenium oxide electrode with metal doping coupled with oxygen vacancies; Examples 11-13 are examples of modulating the dopant metal type of the monolithic ruthenium oxide electrode with metal doping coupled with oxygen vacancies.

[0042] Example 1

[0043] The fabrication of a monolithic ruthenium oxide-based electrode doped with lanthanum and coupled with oxygen vacancies includes the following steps:

[0044] 1. Place 1cm 2 The titanium mesh was sequentially placed in deionized water, 2 mol / L hydrochloric acid aqueous solution, acetone, ethanol, and deionized water for ultrasonic cleaning for 15 minutes each, and then placed in a 60℃ vacuum oven for drying for 4 hours.

[0045] 2. Place the cleaned titanium mesh under an infrared lamp, and drop 0.1 mL of an ethanol solution containing 0.05 mol / L ruthenium chloride and 5 mmol / L lanthanum nitrate onto the titanium mesh. In an air atmosphere, heat the mesh to 350 °C at a programmed rate of 5 °C / min for 240 min, and then cool it down to 30 °C at a programmed rate of 2 °C / min to obtain a monolithic ruthenium oxide-based electrode with lanthanum doped and coupled with oxygen vacancies.

[0046] The scanning electron microscope image of the material is shown in Figure 1. The prepared lanthanum-doped ruthenium oxide-based monolithic electrode with oxygen vacancies has a macroporous structure of titanium mesh, and some nanorods are grown on the surface of the titanium mesh.

[0047] Example 2

[0048] The fabrication of a monolithic ruthenium oxide-based electrode doped with lanthanum and coupled with oxygen vacancies includes the following steps:

[0049] 1. Place 100cm 2 The titanium mesh was sequentially placed in deionized water, 2 mol / L hydrochloric acid aqueous solution, acetone, ethanol, and deionized water for ultrasonic cleaning for 15 minutes each, and then placed in a 60℃ vacuum oven for drying for 4 hours.

[0050] 2. Place the cleaned titanium mesh under an infrared lamp, and drop-coat 0.1 mL of an ethanol solution containing 0.05 mol / L ruthenium chloride and 5 mmol / L lanthanum nitrate onto the titanium mesh. Then, under an air atmosphere, heat the mesh to 350 °C at a programmed rate of 5 °C / min for 240 min, and then cool it down to 30 °C at a programmed rate of 2 °C / min to obtain a monolithic ruthenium oxide-based electrode with lanthanum doped and coupled with oxygen vacancies.

[0051] The scanning electron microscope image of the material is shown in Figure 1. Compared with the original titanium mesh, the prepared ruthenium oxide-based monolithic electrode with lanthanum doping and oxygen vacancies has nanorod-like materials growing on its surface, with a length of about 300 nanometers. The image of the material is shown in Figure 2, which fully illustrates the scalability of the monolithic electrode in industrial production.

[0052] Example 3

[0053] The fabrication of a monolithic ruthenium oxide-based electrode doped with lanthanum and coupled with oxygen vacancies includes the following steps:

[0054] 1. Place 1cm 2 The foamed titanium was sequentially placed in deionized water, 2 mol / L hydrochloric acid aqueous solution, acetone, ethanol, and deionized water for ultrasonic cleaning for 15 minutes each, and then placed in a 60℃ vacuum oven for drying for 4 hours.

[0055] 2. Place the cleaned foamed titanium under an infrared lamp, and drop 0.1 mL of an ethanol solution containing 0.05 mol / L ruthenium chloride and 5 mmol / L lanthanum nitrate onto the foamed titanium. Then, under an air atmosphere, heat the solution to 350 °C at a programmed rate of 5 °C / min for 240 min, and then cool it down to 30 °C at a programmed rate of 2 °C / min to obtain a monolithic ruthenium oxide-based electrode with lanthanum doped and coupled with oxygen vacancies.

[0056] Example 4

[0057] The fabrication of a monolithic ruthenium oxide-based electrode doped with lanthanum and coupled with oxygen vacancies includes the following steps:

[0058] 1. Place 1cm 2 The carbon paper was placed in deionized water, 2 mol / L hydrochloric acid aqueous solution, acetone, ethanol and deionized water respectively for ultrasonic cleaning for 15 minutes each, and then placed in a vacuum oven at 60℃ for drying for 4 hours.

[0059] 2. Place the cleaned carbon paper under an infrared lamp, and drop 0.1 mL of an ethanol solution containing 0.05 mol / L ruthenium chloride and 5 mmol / L lanthanum nitrate onto the carbon paper. Then, in an air atmosphere, heat the paper to 350 °C at a programmed rate of 5 °C / min for 240 min, and then cool it down to 30 °C at a programmed rate of 2 °C / min to obtain a monolithic ruthenium oxide-based electrode with lanthanum doped and coupled with oxygen vacancies.

[0060] Example 5

[0061] The fabrication of a monolithic ruthenium oxide-based electrode doped with lanthanum and coupled with oxygen vacancies includes the following steps:

[0062] 1. Place 1cm 2 The carbon cloth was placed in deionized water, 2 mol / L hydrochloric acid aqueous solution, acetone, ethanol and deionized water respectively for ultrasonic cleaning for 15 minutes each, and then placed in a vacuum oven at 60℃ for drying for 4 hours.

[0063] 2. Place the cleaned carbon cloth under an infrared lamp, and drop 0.1 mL of an ethanol solution containing 0.05 mol / L ruthenium chloride and 5 mmol / L lanthanum nitrate onto the carbon cloth. Then, in an air atmosphere, heat the carbon cloth to 350 °C at a programmed rate of 5 °C / min for 240 min, and then cool it down to 30 °C at a programmed rate of 2 °C / min to obtain a monolithic ruthenium oxide-based electrode with lanthanum doped and coupled with oxygen vacancies.

[0064] Example 6

[0065] The fabrication of a monolithic ruthenium oxide-based electrode doped with lanthanum and coupled with oxygen vacancies includes the following steps:

[0066] 1. Place 1cm 2The carbon felt was placed in deionized water, 2 mol / L hydrochloric acid aqueous solution, acetone, ethanol and deionized water respectively for ultrasonic cleaning for 15 minutes each, and then placed in a vacuum oven at 60℃ for drying for 4 hours.

[0067] 2. Place the cleaned carbon felt under an infrared lamp, and drop 0.1 mL of an ethanol solution containing 0.05 mol / L ruthenium chloride and 5 mmol / L lanthanum nitrate onto the carbon felt. Then, under an air atmosphere, heat the carbon felt to 350 °C at a programmed rate of 5 °C / min for 240 min, and then cool it down to 30 °C at a programmed rate of 2 °C / min to obtain a monolithic ruthenium oxide-based electrode with lanthanum doped and coupled with oxygen vacancies.

[0068] Examples 1-6 above are modulation examples of ruthenium oxide-based monolithic electrodes with lanthanum doping coupled with oxygen vacancies under different conductive substrate types. These examples demonstrate that, under the control of a single variable, ruthenium oxide-based monolithic electrodes with lanthanum doping coupled with oxygen vacancies can be prepared by changing different conductive substrate types. That is, the preparation method involved in this invention can realize ruthenium oxide-based monolithic electrode materials with lanthanum doping coupled with oxygen vacancies on different conductive substrates. The electrocatalytic performance of such materials is verified and illustrated in the application examples.

[0069] Example 7

[0070] The fabrication of a monolithic ruthenium oxide-based electrode doped with lanthanum and coupled with oxygen vacancies includes the following steps:

[0071] 1. Place 1cm 2 The titanium mesh was sequentially placed in deionized water, 2 mol / L hydrochloric acid aqueous solution, acetone, ethanol, and deionized water for ultrasonic cleaning for 15 minutes each, and then placed in a 60℃ vacuum oven for drying for 4 hours.

[0072] 2. Place the cleaned titanium mesh under an infrared lamp, and drop-coat 0.1 mL of an ethanol solution containing 0.05 mol / L ruthenium chloride and 5 mmol / L lanthanum nitrate onto the titanium mesh. Then, under an air atmosphere, heat the mesh to 300 °C at a programmed rate of 5 °C / min for 240 min, and then cool it down to 30 °C at a programmed rate of 2 °C / min to obtain a monolithic ruthenium oxide-based electrode with lanthanum doped and coupled with oxygen vacancies.

[0073] Example 8

[0074] The fabrication of a monolithic ruthenium oxide-based electrode doped with lanthanum and coupled with oxygen vacancies includes the following steps:

[0075] 1. Place 1cm 2 The titanium mesh was sequentially placed in deionized water, 2 mol / L hydrochloric acid aqueous solution, acetone, ethanol, and deionized water for ultrasonic cleaning for 15 minutes each, and then placed in a 60℃ vacuum oven for drying for 4 hours.

[0076] 2. Place the cleaned titanium mesh under an infrared lamp, and drop 0.1 mL of an ethanol solution containing 0.05 mol / L ruthenium chloride and 5 mmol / L lanthanum nitrate onto the titanium mesh. Then, under an air atmosphere, heat the mesh to 400 °C at a programmed rate of 5 °C / min for 240 min, and then cool it down to 30 °C at a programmed rate of 2 °C / min to obtain a monolithic ruthenium oxide-based electrode with lanthanum doped and coupled with oxygen vacancies.

[0077] Example 9

[0078] The fabrication of a monolithic ruthenium oxide-based electrode doped with lanthanum and coupled with oxygen vacancies includes the following steps:

[0079] 1. Place 1cm 2 The titanium mesh was sequentially placed in deionized water, 2 mol / L hydrochloric acid aqueous solution, acetone, ethanol, and deionized water for ultrasonic cleaning for 15 minutes each, and then placed in a 60℃ vacuum oven for drying for 4 hours.

[0080] 2. Place the cleaned titanium mesh under an infrared lamp, and drop 0.1 mL of an ethanol solution containing 0.05 mol / L ruthenium chloride and 5 mmol / L lanthanum nitrate onto the titanium mesh. Then, under an air atmosphere, heat the mesh to 500 °C at a programmed rate of 5 °C / min for 240 min, and then cool it down to 30 °C at a programmed rate of 2 °C / min to obtain a monolithic ruthenium oxide-based electrode with lanthanum doped and coupled with oxygen vacancies.

[0081] Examples 7-9 above are examples of modulating the heating temperature of ruthenium oxide-based monolithic electrodes doped with lanthanum and coupled with oxygen vacancies. These examples demonstrate that, under the control of a single variable, different heating temperatures can be used to prepare monolithic electrodes containing different numbers of oxygen vacancies (as shown in Figure 5). That is, the preparation method involved in this invention can realize lanthanum oxide-based monolithic electrode materials with different numbers of oxygen vacancies. The electrocatalytic performance of such materials is verified and illustrated in the application examples.

[0082] Example 10

[0083] The fabrication of a monolithic ruthenium oxide-based electrode with metal doping and oxygen vacancies includes the following steps:

[0084] 1. Place 1cm 2 The titanium mesh was sequentially placed in deionized water, 2 mol / L hydrochloric acid aqueous solution, acetone, ethanol, and deionized water for ultrasonic cleaning for 15 minutes each, and then placed in a 60℃ vacuum oven for drying for 4 hours.

[0085] 2. Place the cleaned titanium mesh under an infrared lamp, and drop 0.1 mL of an ethanol solution containing 0.05 mol / L ruthenium chloride and different concentrations of lanthanum nitrate solutions (5, 7, 10, and 15 mmol / L, named 5La-RuO2-Example 10, 7La-RuO2-Example 10, 10La-RuO2-Example 10, and 15La-RuO2-Example 10, respectively) onto the titanium mesh. Then, under an air atmosphere, the temperature is increased to 350°C at a programmed rate of 5°C / min and heated for 240 min, followed by a cooling rate of 2°C / min to 30°C, thus obtaining four metal-doped ruthenium oxide-based monolithic electrodes coupled with oxygen vacancies.

[0086] Example 11

[0087] The fabrication of a monolithic ruthenium oxide-based electrode with metal doping and oxygen vacancies includes the following steps:

[0088] 1. Place 1cm 2 The titanium mesh was sequentially placed in deionized water, 2 mol / L hydrochloric acid aqueous solution, acetone, ethanol, and deionized water for ultrasonic cleaning for 15 minutes each, and then placed in a 60℃ vacuum oven for drying for 4 hours.

[0089] 2. Place the cleaned titanium mesh under an infrared lamp, and drop-coat 0.1 mL of an ethanol solution containing 0.05 mol / L ruthenium chloride and 5 mmol / L lanthanum nitrate, or 5 mmol / L cerium nitrate, or 5 mmol / L praseodymium nitrate, or 5 mmol / L europium nitrate onto the titanium mesh. Then, under an air atmosphere, heat the mesh to 350 °C at a programmed rate of 5 °C / min for 240 min, and then cool it down to 30 °C at a programmed rate of 2 °C / min to obtain a monolithic ruthenium oxide-based electrode with four metal doped oxygen vacancies.

[0090] Example 12

[0091] The fabrication of a monolithic ruthenium oxide-based electrode with metal doping and oxygen vacancies includes the following steps:

[0092] 1. Place 1cm 2 The titanium mesh was sequentially placed in deionized water, 2 mol / L hydrochloric acid aqueous solution, acetone, ethanol, and deionized water for ultrasonic cleaning for 15 minutes each, and then placed in a 60℃ vacuum oven for drying for 4 hours.

[0093] 2. Place the cleaned titanium mesh under an infrared lamp, and drop-coat 0.1 mL of an ethanol solution containing 0.05 mol / L ruthenium chloride and 5 mmol / L manganese chloride, or 5 mmol / L chromium chloride, or 5 mmol / L ferric chloride, or 5 mmol / L cobalt chloride, or 5 mmol / L nickel chloride onto the titanium mesh. Then, under an air atmosphere, heat the mesh to 350 °C at a programmed rate of 5 °C / min for 240 min, and then cool it down to 30 °C at a programmed rate of 2 °C / min to obtain a monolithic ruthenium oxide-based electrode with five metal doped oxygen vacancies.

[0094] Example 13

[0095] The fabrication of a monolithic ruthenium oxide-based electrode with metal doping and oxygen vacancies includes the following steps:

[0096] 1. Place 1cm 2 The titanium mesh was sequentially placed in deionized water, 2 mol / L hydrochloric acid aqueous solution, acetone, ethanol, and deionized water for ultrasonic cleaning for 15 minutes each, and then placed in a 60℃ vacuum oven for drying for 4 hours.

[0097] 2. Place the cleaned titanium mesh under an infrared lamp, and drop 0.1 mL of an ethanol solution containing 0.05 mol / L ruthenium chloride and 5 mmol / L molybdenum chloride, or 5 mmol / L tungsten chloride, or 5 mmol / L tantalum chloride onto the titanium mesh. Then, under an air atmosphere, heat the mesh to 350 °C at a programmed rate of 5 °C / min for 240 min, and then cool it down to 30 °C at a programmed rate of 2 °C / min to obtain a monolithic ruthenium oxide-based electrode with three metal doped oxygen vacancies.

[0098] Examples 10-13 above are modulation examples of ruthenium oxide-based monolithic electrodes doped with different types of metals, including lanthanides, transition metals, and high-valence metals. These examples demonstrate that, under the control of a single variable, changing the type of different doped metal precursors can yield corresponding metal-doped ruthenium oxide-based monolithic catalytic electrodes coupled with oxygen vacancies. That is, the preparation method involved in this invention can realize ruthenium oxide-based monolithic electrode materials doped with various types of metals, including lanthanides, transition metals, and high-valence metals coupled with oxygen vacancies. The electrocatalytic performance of such materials is verified and illustrated in application examples.

[0099] Application Example 1

[0100] Using the monolithic ruthenium oxide-based electrodes with lanthanum doped and coupled oxygen vacancies on different substrates obtained in the above embodiments as the anode catalysts for acidic electrocatalytic water splitting systems, the application potential of such materials in the oxygen evolution reaction of acidic water electrolysis is confirmed.

[0101] 1. Test System Setup: The test setup is a three-electrode system. The reference electrode is Ag / AgO (1 M KCl solution), the counter electrode is a C rod, and the working electrode has an area of ​​1 cm². 2 A monolithic ruthenium oxide-based electrode, doped with lanthanum and coupled with oxygen vacancies, was used with a 0.5 M H₂SO₄ solution as the electrolyte. During the test, a gas bubbling device was employed to saturate the electrolyte with O₂.

[0102] 2. Catalytic performance evaluation method: The electrolytic cell temperature was maintained at 25℃. The performance of the catalyst in the oxygen evolution reaction was tested by polarization curve. The potential required by the catalyst to reach a certain oxidation current density was compared. The specific test results are shown in Figure 3-4.

[0103] Comparative analysis shows that the ruthenium oxide-based monolithic electrode doped with lanthanum and coupled with oxygen vacancies exhibits superior oxygen evolution reaction (OER) performance compared to the currently available commercial catalyst RuO2. This confirms that this type of lanthanum-doped ruthenium oxide-based monolithic electrode possesses excellent OER performance in water electrolysis under acidic conditions. Different conductive substrates and calcination temperatures have varying effects on the structure of the ruthenium oxide-based monolithic catalyst, thereby influencing its activity. By adjusting the calcination temperature and using different substrates, its catalytic activity in the anodic OER of electrocatalytic water splitting can be effectively improved.

[0104] Application Example 2

[0105] Using ruthenium oxide-based monolithic electrodes with different metal types coupled with oxygen vacancies obtained in the above embodiments as anolyte catalysts in acidic electrocatalytic water splitting systems, the application potential of such materials in the oxygen evolution reaction of acidic water electrolysis is confirmed.

[0106] 1. Test System Setup: The test setup is a three-electrode system. The reference electrode is Ag / AgO (1 M KCl solution), the counter electrode is a C rod, and the working electrode has an area of ​​1 cm². 2 A monolithic ruthenium oxide-based electrode with metal doping and oxygen vacancies was used, with a 0.5 M H₂SO₄ solution as the electrolyte. During the test, a gas bubbling device was employed to saturate the electrolyte with O₂.

[0107] 2. Catalytic performance evaluation method: The electrolytic cell temperature was maintained at 25℃. The performance of the catalyst in the oxygen evolution reaction was tested by polarization curve. The potential required by the catalyst to reach a certain oxidation current density was compared. The specific test results are shown in Figure 6-10.

[0108] The comparison shows that the monolithic ruthenium oxide electrode doped with lanthanum and coupled with oxygen vacancies has a much higher oxygen evolution performance in acidic water electrolysis than other lanthanide metals, transition metals and high-valence metals, and even higher than commercial ruthenium oxide materials. This confirms that this type of monolithic ruthenium oxide electrode doped with lanthanum and coupled with oxygen vacancies has excellent activity and stability in acidic water electrolysis for oxygen evolution.

[0109] Application Examples 1-2 demonstrate that in the anodic reaction of acidic water electrolysis, compared to monolithic ruthenium oxide (RuO2) catalytic electrodes with lanthanum doping and oxygen vacancies, the lanthanum-doped RuO2-coupled electrode exhibits superior catalytic performance and maintains long-term stability under strong acid and high current conditions. This is attributed to the porous structure of the titanium mesh facilitating proton transport, the ability of lanthanum to modulate the electronic structure of ruthenium in RuO2 to prevent over-oxidation and dissolution, and the provision of more catalytically active sites by oxygen vacancies. Therefore, in practical electrocatalytic applications, the coupling of both metal doping and oxygen vacancies must be considered to select a ruthenium oxide-based monolithic electrode that better suits production requirements.

[0110] The above embodiments are merely preferred embodiments of the present invention and are not intended to limit the implementation. The scope of protection of the present invention should be determined by the scope defined in the claims. Other variations or modifications can be made based on the above description. Obvious variations or modifications derived therefrom are still within the scope of protection of the present invention.

Claims

1. A method for preparing a monolithic ruthenium oxide-based electrode doped with lanthanum metal and coupled with oxygen vacancies, comprising the following steps: (1) Remove impurities from the surface of the metal conductive substrate or carbon substrate; (2) Prepare an aqueous solution containing ruthenium salt and lanthanum salt; (3) Under infrared lamp irradiation, drop-coat the solution prepared in step (2) onto the metal conductive substrate or carbon substrate and dry it; (4) calcine the substrate precursor obtained in step (3) at 300~500℃ for 1~5h in an oxidizing atmosphere, and then cool it down to obtain the substrate; the carbon substrate is one of carbon paper, carbon cloth or carbon felt; the metal conductive substrate is one of titanium mesh or foamed titanium; the area of ​​the carbon substrate or metal conductive substrate is 1~100 cm². 2 In step (1), impurities on the surface of the metal conductive substrate or carbon substrate are removed using either of the following two methods:

1. Solution cleaning method: The substrate is placed in deionized water, hydrochloric acid solution, acetone, or ethanol, and cleaned by ultrasonication or stirring. Finally, it is cleaned again with deionized water and dried by blowing or baking. The order of deionized water, hydrochloric acid solution, acetone, and ethanol is not limited.

2. Hydrogen reduction method: The substrate is reduced and purged at 100-300 °C for more than 1 hour in a reducing atmosphere of hydrogen or an inert gas containing hydrogen. Finally, it is cooled to room temperature and taken out for use. In step (2), the ruthenium salt is one of carbonyl ruthenium, ruthenium chloride, or ruthenium acetylacetonate. The concentration of the ruthenium salt is 0.01 mol / L to 0.05 mol / L, and the concentration of the lanthanum salt is 3 mmol / L to 50 mmol / L. The solvent is water.

2. The preparation method according to claim 1, characterized in that: In step (3), the droplet amount on the substrate surface is 100–400 μL / cm. 2 .

3. The preparation method according to claim 1, characterized in that: The oxidizing atmosphere mentioned in step (4) is either air or oxygen; the heating process is as follows: the temperature is increased to 300-500℃ at a heating rate of 5-10℃ / min, and the holding time is 2-4 h.

4. The monolithic lanthanum-doped ruthenium oxide-based electrode with oxygen vacancy coupling obtained by the preparation method according to any one of claims 1-3.

5. The application of the monolithic lanthanum-doped ruthenium oxide-based electrode with oxygen vacancy coupling as described in claim 4 in acidic electrocatalytic water splitting reaction, characterized in that: It can be used as an anode material in acidic electrocatalytic water splitting reactions for efficient water electrolysis and oxygen evolution.

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