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

Abstract

The invention discloses a preparation method and application of a metal lanthanum doped oxygen vacancy coupled ruthenium oxide-based integral electrode, and belongs to the technical field of electrochemical materials. The preparation method comprises the following steps: firstly, removing impurities on the surface of a metal conductive substrate or a carbon substrate, then preparing an aqueous solution containing ruthenium salt and lanthanum salt, dispensing the prepared solution on the metal conductive substrate or the carbon substrate under the irradiation of an infrared lamp, drying, roasting for 1-5 hours at 300-500 DEG C in an oxidizing atmosphere, and cooling, thereby obtaining the product, the preparation method disclosed by the invention can be used for preparing the unsupported integral ruthenium oxide-based catalyst, and is wide in universality, easy in condition control and easy to operate. The lanthanum metal doped oxygen vacancy coupled ruthenium oxide-based integral electrode prepared by the method can be used as an anode material for acidic oxygen evolution reaction, and shows excellent performance and wide application prospect.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrochemical materials, and in particular, relates to a preparation method and application of an acid-resistant metal lanthanum doped ruthenium oxide-based integral electrode coupled with oxygen vacancies. Background Art

[0002] The excessive use of fossil fuels not only leads to resource depletion, but also brings serious environmental problems such as greenhouse effect and air pollution. There is an urgent need for storage and conversion technologies of renewable energy. Hydrogen (H2) is one of the most promising new energy sources, the best energy carrier and an essential choice for future low-carbon energy (Peter et al., ACS Energy Lett., 2023, 8, 3330). Polymer electrolyte membrane water electrolyzers (PEMWEs) driven by renewable electricity are considered to be a promising green hydrogen production technology. The anode oxygen evolution reaction (OER) is one of the main obstacles to the practical application of PEMWEs. The strong acidic environment and extremely oxidative working conditions make it extremely challenging to develop highly active and stable OER electrocatalysts (Wang et al., ACS Cat., 2023, 13, 8670; Chong et al., Science, 2023, 380, 609). Ruthenium oxide (Ru)-based materials, as acidic OER catalysts, have the advantages of high activity and the lowest price in the precious metal family, but their long-term durability is far from satisfactory. In order to improve the stability of ruthenium oxide-based catalysts, a "metal doping" strategy has been proposed. Metal doping can enhance the covalency of metal-oxygen bonds and accelerate electron transfer during the OER process. At the same time, doped metals regulate the electronic structure of ruthenium oxide to prevent further oxidation and dissolution (Qin et al., Nano Lett., 2021, 21, 5774). The proposal of this strategy makes it possible for the catalytic application of ruthenium oxide in harsh environments, and also provides new ideas for the development of highly active and stable acidic water electrolysis catalysts.

[0003] Studies have shown that controllable vacancy defects can increase the number of surface active sites and the catalytic ability of active sites, and are expected to improve the activity and stability of acidic OER catalysts. At present, the research on "vacancy defects" is limited to the modification of nanocatalysts. The prepared ruthenium oxide-based catalyst is a powder material, which needs to be further prepared into a supported electrode to participate in the reaction (Wang et al., Nat. Commun., 2023, 14, 1412). The preparation process of supported electrodes has the following shortcomings: on the one hand, the use of substrates and binders increases the process cost. On the other hand, the supported electrodes are under strong stirring and high airflow conditions. The catalyst will fall off the substrate after long-term testing, resulting in a decrease in acidic OER activity and stability. More importantly, the limited catalyst loading and active sites limit the catalytic performance of the electrode per unit area for water electrolysis. Therefore, the development of a monolithic ruthenium oxide catalytic electrode is very necessary to promote the development of acidic water electrolysis oxygen evolution reaction. At present, there are still challenges in the preparation of monolithic catalytic electrodes, and no related research on the use of metal-doped ruthenium oxide monolithic catalytic electrodes with coupled oxygen vacancies for water electrolysis technology has been reported. Summary of the invention

[0004] In view of this, the purpose of the present invention is to provide a method for preparing a metal lanthanum-doped coupled oxygen vacancy ruthenium oxide-based monolithic catalytic electrode for acidic water electrolysis oxygen evolution reaction and its application. The present invention obtains a lanthanum-doped ruthenium oxide monolithic electrode material by simultaneously dripping a ruthenium salt and a lanthanide metal salt solution on the surface of a titanium mesh, irradiating the mesh with an infrared lamp, and calcining the resulting solution in an air atmosphere. The method is simple to operate and easy to scale up. The self-supporting electrode material with in-situ growth is prepared, and as an anode material for the acidic water electrolysis oxygen evolution reaction, it exhibits excellent electrocatalytic performance and has broad application prospects.

[0005] In order to achieve the above object, the technical solution of the present invention is as follows:

[0006] The present invention provides a method for preparing a metal lanthanum doped coupled oxygen vacancy ruthenium oxide-based integral electrode, comprising the following steps:

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

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

[0009] (3) under the irradiation of an infrared lamp, drop-coating the solution prepared in step (2) on the surface of a metal conductive substrate or a carbon substrate, and drying;

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

[0011] Based on the above technical solution, further, in step (1), any one of the following two methods is used to remove impurities on the surface of the metal conductive substrate or the carbon substrate:

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

[0013] 2. Hydrogen reduction method: The substrate is reduced and purged in a reducing atmosphere of hydrogen or an inert gas containing hydrogen at 100-300°C 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 cm 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, and the concentration of the lanthanum salt is 3 mmol / L to 50 mmol / L; and the solvent is one of water or ethanol.

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

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

[0018] Another aspect of the present invention provides a metal lanthanum doped coupled oxygen vacancy ruthenium oxide-based integral electrode obtained by the above-mentioned preparation method, wherein the integral electrode has a porous structure.

[0019] On the other hand, the present invention provides the use of the above-mentioned metal lanthanum doped coupled oxygen vacancy ruthenium oxide-based integral electrode in an acidic electrocatalytic water decomposition reaction, which is used as an anode material in an acidic water electrolysis reaction for efficient water electrolysis and oxygen evolution, and has 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 non-loaded integral electrode. This method has wide universality, simple conditions and is easy to operate.

[0022] 2. The metal-doped coupled oxygen vacancy ruthenium oxide monolithic electrode prepared by the present invention has controllable doping metal type, oxygen vacancy content and conductive substrate, and can be adjusted according to different requirements of catalytic production.

[0023] 3. The metal-doped coupled oxygen vacancy ruthenium oxide monolithic electrode prepared by the present invention has a stable structure, excellent catalytic performance and good durability in a strong acid, strong alkali and strong corrosive environment.

[0024] 4. The metal-doped coupled oxygen vacancy ruthenium oxide integral electrode prepared by the present invention does not require a binder, saves production costs, simplifies electrode processing technology, and can avoid the difficulties of powder shedding and electrode inactivation in practical applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a scanning electron microscope morphology of the ruthenium oxide monolithic electrode with a titanium mesh as a substrate and metal lanthanum doped coupled oxygen vacancies in Example 1, wherein the magnifications of a, b, c, and d are 110 times, 500 times, 1000 times, and 24000 times, respectively;

[0026] Figure 2 This is a picture of the appearance of the large-sized metal-doped coupled oxygen vacancy ruthenium oxide monolithic electrode in Example 2, with a size of 10*10 cm;

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

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

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

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

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

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

[0033] Fig. 9 This is a performance diagram of the ruthenium oxide-based integral electrode of Example 13 in the anodic oxygen evolution reaction in acidic water electrolysis.

[0034] Fig.10 The ruthenium oxide-based monolithic electrode of Example 1 was subjected to strong acid (0.5M H2SO4) and high current (100mAcm -2 )’s long term stability performance diagram. DETAILED DESCRIPTION

[0035] The following is a detailed description of the entire material preparation process through examples, but the scope of the claims of the present invention is not limited by these examples. At the same time, the examples only provide some conditions for achieving this purpose, but do not mean that these conditions must be met to achieve this purpose.

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

[0037] The products in this example were detected by the following instruments and methods:

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

[0039] The vacancy degree diagrams of Examples 1, 7-9 were characterized by electron paramagnetic resonance (EPR);

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

[0041] Examples 1-10 are examples of adjusting the conductive substrate type and sintering temperature of the metal-doped ruthenium oxide integral electrode coupled with oxygen vacancies; Examples 11-13 are examples of adjusting the doping metal type of the metal-doped ruthenium oxide integral electrode coupled with oxygen vacancies.

[0042] Example 1

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

[0044] 1. 1cm 2 The titanium mesh was ultrasonically cleaned in deionized water, 2 mol / L hydrochloric acid solution, acetone, ethanol, and deionized water for 15 minutes each, and then placed in a vacuum oven at 60°C and dried for 4 hours.

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

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

[0047] Example 2

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

[0049] 1. Place 100cm 2 The titanium mesh was ultrasonically cleaned in deionized water, 2 mol / L hydrochloric acid solution, acetone, ethanol, and deionized water for 15 minutes each, and then placed in a vacuum oven at 60°C and dried for 4 hours.

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

[0051] The scanning electron microscopy of this material Figure 1 As shown, compared with the original titanium mesh, the surface of the prepared metal lanthanum doped ruthenium oxide-based monolithic electrode coupled with oxygen vacancies grows nanorod-like materials with a length of about 300 nanometers; the picture of the material is shown in Figure 2 As shown, it fully demonstrates the scalability of the integrated electrode in industrial production.

[0052] Example 3

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

[0054] 1. 1cm2 The titanium foam 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 vacuum oven at 60°C for 4 hours.

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

[0056] Example 4

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

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

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

[0060] Example 5

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

[0062] 1. 1cm 2 The carbon cloth was 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 vacuum oven at 60°C and dried for 4 hours;

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

[0064] Example 6

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

[0066] 1. 1cm 2 The carbon felt 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 vacuum oven at 60°C for 4 hours;

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

[0068] The above Examples 1-6 are examples of adjusting different conductive substrate types of ruthenium oxide-based integral electrodes doped with metal lanthanum and coupled with oxygen vacancies. The above examples show that under the regulation of a single variable, by changing different conductive substrate types, ruthenium oxide-based integral electrodes doped with metal lanthanum and coupled with oxygen vacancies can be prepared, that is, the preparation method involved in the present invention can realize ruthenium oxide-based integral electrode materials doped with metal lanthanum and coupled with oxygen vacancies on different conductive substrates, and the electrocatalytic performance of such materials is verified and explained in the application examples.

[0069] Example 7

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

[0071] 1. 1cm 2 The titanium mesh was ultrasonically cleaned in deionized water, 2 mol / L hydrochloric acid solution, acetone, ethanol, and deionized water for 15 minutes each, and then placed in a vacuum oven at 60°C and dried for 4 hours.

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

[0073] Example 8

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

[0075] 1. 1cm 2 The titanium mesh was ultrasonically cleaned in deionized water, 2 mol / L hydrochloric acid solution, acetone, ethanol, and deionized water for 15 minutes each, and then placed in a vacuum oven at 60°C and dried for 4 hours.

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

[0077] Example 9

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

[0079] 1. 1cm 2 The titanium mesh was ultrasonically cleaned in deionized water, 2 mol / L hydrochloric acid solution, acetone, ethanol, and deionized water for 15 minutes each, and then placed in a vacuum oven at 60°C and dried for 4 hours.

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

[0081] The above Examples 7-9 are examples of adjusting different heating temperatures for the ruthenium oxide-based monolithic electrode doped with metal lanthanum and coupled with oxygen vacancies. The above examples show that, under the control of a single variable, by changing different heating temperatures, monolithic electrodes containing different numbers of oxygen vacancies (such as Figure 5 As shown), that is, the preparation method involved in the present invention can realize ruthenium oxide-based integral electrode materials doped with metal lanthanum with different numbers of oxygen vacancies, and the electrocatalytic performance of such materials is verified and explained in the application examples.

[0082] Example 10

[0083] The preparation of a metal-doped ruthenium oxide-based monolithic electrode coupled with oxygen vacancies comprises the following steps:

[0084] 1. 1cm 2The titanium mesh was ultrasonically cleaned in deionized water, 2 mol / L hydrochloric acid solution, acetone, ethanol, and deionized water for 15 minutes each, and then placed in a vacuum oven at 60°C and dried for 4 hours.

[0085] 2. Place the cleaned titanium mesh under an infrared lamp, and drop an ethanol solution (0.1 mL) containing 0.05 mol / L ruthenium chloride and different concentrations of lanthanum nitrate solution (5, 7, 10, 15 mmol / L, named 5La-RuO2-Implementation Example 10, 7La-RuO2-Implementation Example 10, 10La-RuO2-Implementation Example 10, 15La-RuO2-Implementation Example 10, respectively) on the titanium mesh. Then, in an air atmosphere, heat the mixture to 350°C at a rate of 5°C / min, heat for 240 min, and then cool the mixture to 30°C at a rate of 2°C / min to obtain four metal-doped ruthenium oxide-based integral electrodes with coupled oxygen vacancies.

[0086] Embodiment 11

[0087] The preparation of a metal-doped ruthenium oxide-based monolithic electrode coupled with oxygen vacancies comprises the following steps:

[0088] 1. 1cm 2 The titanium mesh was ultrasonically cleaned in deionized water, 2 mol / L hydrochloric acid solution, acetone, ethanol, and deionized water for 15 minutes each, and then placed in a vacuum oven at 60°C and dried for 4 hours.

[0089] 2. Place the cleaned titanium mesh under an infrared lamp, and drop an ethanol solution (0.1 mL) 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 on the titanium mesh. Then, in an air atmosphere, heat the mixture to 350°C at a rate of 5°C / min, heat for 240 min, and then cool the mixture to 30°C at a rate of 2°C / min to obtain a ruthenium oxide-based integral electrode with four metal-doped coupled oxygen vacancies.

[0090] Example 12

[0091] The preparation of a metal-doped ruthenium oxide-based monolithic electrode coupled with oxygen vacancies comprises the following steps:

[0092] 1. 1cm 2 The titanium mesh was ultrasonically cleaned in deionized water, 2 mol / L hydrochloric acid solution, acetone, ethanol, and deionized water for 15 minutes each, and then placed in a vacuum oven at 60°C and dried for 4 hours.

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

[0094] Example 13

[0095] The preparation of a metal-doped ruthenium oxide-based monolithic electrode coupled with oxygen vacancies comprises the following steps:

[0096] 1. 1cm 2 The titanium mesh was ultrasonically cleaned in deionized water, 2 mol / L hydrochloric acid solution, acetone, ethanol, and deionized water for 15 minutes each, and then placed in a vacuum oven at 60°C and dried for 4 hours.

[0097] 2. Place the cleaned titanium mesh under an infrared lamp, and drop an ethanol solution (0.1 mL) 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 on the titanium mesh. Then, in an air atmosphere, heat the mixture to 350°C at a rate of 5°C / min, heat for 240 min, and then cool the mixture to 30°C at a rate of 2°C / min to obtain a ruthenium oxide-based integral electrode with three metal doped coupled oxygen vacancies.

[0098] The above embodiments 10-13 are examples of adjusting different types of doped metals including lanthanide metals, transition metals and high-valent metal-doped ruthenium oxide-based monolithic electrodes. The above embodiments show that under the regulation of a single variable, by changing the types of different types of doped metal precursors, corresponding metal-doped coupled oxygen vacancies ruthenium oxide-based monolithic catalytic electrodes can be prepared, that is, the preparation method involved in the present invention can realize multiple types of metal doping including lanthanide metals, transition metals and high-valent metal doped coupled oxygen vacancies ruthenium oxide-based monolithic electrode materials, and the electrocatalytic performance of such materials is verified and explained in the application examples.

[0099] Application Example 1

[0100] The metal lanthanum doped ruthenium oxide-based monolithic electrodes with coupled oxygen vacancies on different substrates obtained in the above examples were used as anode catalysts in acidic electrocatalytic water decomposition systems, confirming the application potential of such materials in acidic water electrolysis oxygen evolution reactions.

[0101] 1. Test system construction: The test device is a three-electrode system, the reference electrode is Ag / AgO (1M KCl solution), the counter electrode is a C rod, and the working electrode is a 1cm 2 The metal lanthanum doped coupled oxygen vacancy ruthenium oxide based monolithic electrode, the electrolyte is 0.5M H2SO4 solution. During the test, the gas bubbling device is used to saturate the electrolyte with O2.

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

[0103] By comparison, it can be seen that the oxygen evolution reaction performance of the ruthenium oxide-based monolithic electrode doped with metal lanthanum coupled with oxygen vacancies is higher than that of the current commercial catalyst RuO2, which confirms that this type of ruthenium oxide-based monolithic electrode doped with metal lanthanum coupled with oxygen vacancies has excellent performance in the electrolytic water electrolysis oxygen evolution reaction under acidic conditions. Different conductive substrates and calcination temperatures have different effects on the structure of the ruthenium oxide-based monolithic catalyst, thereby affecting its activity. By adjusting the calcination temperature and different substrates, its catalytic activity in the anode reaction oxygen evolution reaction of electrocatalytic water decomposition can be effectively improved.

[0104] Application Example 2

[0105] The metal-doped ruthenium oxide-based monolithic electrode with coupled oxygen vacancies of different metal species obtained in the above examples was used as an anode catalyst in an acidic electrocatalytic water decomposition system, confirming the application potential of such materials in acidic water electrolysis oxygen evolution reaction.

[0106] 1. Test system construction: The test device is a three-electrode system, the reference electrode is Ag / AgO (1M KCl solution), the counter electrode is a C rod, and the working electrode is a 1cm 2 The metal-doped coupled oxygen vacancy ruthenium oxide-based monolithic electrode was used, and the electrolyte was 0.5M H2SO4 solution. During the test, a gas bubbling device was used to saturate the electrolyte with O2.

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

[0108] By comparison, it can be seen that the performance of ruthenium oxide-based monolithic electrode doped with metal lanthanum and coupled with oxygen vacancies in oxygen evolution in acidic water electrolysis is much higher than that of other lanthanide metals, transition metals and high-valent metal doping, and even higher than commercial ruthenium oxide materials, confirming that this type of ruthenium oxide-based monolithic electrode doped with metal lanthanum and coupled with oxygen vacancies has excellent activity and stability in oxygen evolution in acidic water electrolysis.

[0109] Application Examples 1-2 show that in the anode reaction of acidic water electrolysis, compared with simple conductive substrates, commercial ruthenium oxide materials, and other metal-doped ruthenium oxide-based monolithic catalytic electrodes coupled with oxygen vacancies, metal lanthanum-doped ruthenium oxide-based monolithic electrodes coupled with oxygen vacancies have better catalytic performance and can maintain long-term stability under strong acid and high current. This is due to the porous structure of the titanium mesh that is conducive to proton transport. Metal lanthanum can adjust the electronic structure of ruthenium in ruthenium oxide to prevent dissolution due to excessive oxidation, and oxygen vacancies can provide more catalytic active sites. Therefore, in actual electrocatalytic applications, it is necessary to consider the coupling of metal doping and oxygen vacancies, and choose to prepare a ruthenium oxide-based monolithic catalytic electrode that is more suitable for production needs.

[0110] The above embodiments are only preferred embodiments of the present invention and are not intended to limit the implementation methods. The protection scope of the present invention shall be subject to the scope defined in the claims. Other different forms of changes or modifications may be made based on the above description. Obvious changes or modifications derived therefrom are still within the protection scope of the present invention.

Claims

1. A method for preparing a metal lanthanum doped coupled oxygen vacancy ruthenium oxide-based monolithic electrode, comprising the following steps: (1) Removing impurities from the surface of a metal conductive substrate or a carbon substrate; (2) a prepared aqueous solution containing a ruthenium salt and a lanthanum salt; (3) under the irradiation of an infrared lamp, drop-coating the solution prepared in step (2) on a metal conductive substrate or a carbon substrate, and drying; (4) calcining the substrate precursor obtained in step (3) at 300-500° C. for 1-5 h in an oxidizing atmosphere, and then cooling to obtain the substrate precursor.

2. The preparation method according to claim 1, characterized in that: 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 cm 2 .

3. The preparation method according to claim 1, characterized in that: In step (1), impurities on the surface of the metal conductive substrate or the carbon substrate are removed by any of the following two methods:

1. Solution cleaning method: Place the substrate in deionized water, hydrochloric acid solution, acetone, and ethanol, clean it with ultrasound or stirring, and finally clean it again with deionized water, blow dry or bake it for later use; the order of deionized water, hydrochloric acid solution, acetone, and ethanol is not limited; 2. Hydrogen reduction method: The substrate is reduced and purged in a reducing atmosphere of hydrogen or an inert gas containing hydrogen at 100-300°C for more than 1 hour, and finally cooled to room temperature and taken out for use.

4. The preparation method according to claim 1, characterized in that: 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; and the solvent is one of water or ethanol.

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

6. The preparation method according to claim 1, characterized in that: The oxidizing atmosphere described in step (4) is one of air or oxygen; the heating process is: heating to 300-500°C at a heating rate of 5-10°C / min, and the constant temperature time is 2-4h.

7. The metal lanthanum doped coupled oxygen vacancy ruthenium oxide based monolithic electrode obtained by the preparation method according to any one of claims 1 to 6.

8. Application of the metal lanthanum doped coupled oxygen vacancy ruthenium oxide-based monolithic electrode according to claim 7 in acidic electrocatalytic water decomposition reaction, characterized in that: It is used as anode material in acidic electrocatalytic water splitting reaction for efficient electrolysis of water and oxygen evolution.

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