Preparation method and application of self-supporting oxygen-containing bimetallic Prussian blue analogue electrocatalyst

Abstract

The invention discloses a preparation method and application of a self-supporting oxygen-containing bimetallic Prussian blue analogue electrocatalyst. A CoFe bimetallic prussian blue analogue (CoFe-PBA) is preferentially prepared by utilizing a simple and effective coprecipitation method to serve as a catalyst precursor, then oxygen plasma is creatively adopted for bombardment on the CoFe bimetallic prussian blue analogue, oxygen atoms are introduced while cyano ligands are removed, and preparation of a Co-O-Fe local active structure is achieved. The self-supporting catalyst prepared by the method is uniform and firm in growth, has the possibility of batch and large-area production, and is low in preparation cost, short in reaction period and high in repeatability. Meanwhile, due to introduction of oxygen atoms, lattice oxygen can be successfully activated, overpotential limitation caused by a traditional adsorbate precipitation mechanism is overcome, and ultrahigh oxygen evolution activity and stability under the industrial ampere-level current density are achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrocatalysts, and relates to a method for preparing a self-supporting oxygen-containing bimetallic Prussian blue analogue, and also relates to its application in the preparation of oxygen evolution catalyst materials and oxygen absorption electrodes, and also has potential application value in other fields such as energy development and environmental protection. Background Art

[0002] Under the current severe international situation, energy issues remain one of the main reasons for restricting economic development. The excessive consumption of traditional fossil fuel energy has also further led to energy consumption and environmental degradation problems. Therefore, in the context of the increasingly prominent energy crisis, the use of renewable electricity to decompose water to produce hydrogen is widely regarded as a key foundation for achieving global carbon neutrality.

[0003] There are two half reactions in the electrolysis of water to produce hydrogen. Under different acid-base conditions, the anode process involves a four-electron oxygen evolution reaction (OER), which has problems such as slow kinetics and high overpotential. In the electrolysis of water to produce hydrogen, compared with the hydrogen evolution reaction (HER) occurring at the cathode, the oxygen evolution reaction (OER) occurring on the anode side is considered to be an energy barrier limiting the overall electrocatalytic decomposition of water to produce hydrogen due to its slow reaction kinetics. These disadvantages greatly limit the efficiency of the electrolysis of water. Although precious metal catalysts, such as IrO2 or RuO2, can effectively solve the problem of high overpotential required in the OER process, their high cost also limits the effective deployment of electrolysis of water to produce hydrogen technology.

[0004] In recent years, with the continuous development of new anion exchange membrane water electrolyzer hydrogen production technology, the dependence on precious metal catalysts on the anode side has been further reduced. Therefore, exploring the use of abundant and economical non-precious metals, especially 3d-transition metals, as OER catalysts in alkaline media has gradually become the mainstream of research. However, in the actual operation of AEMWE, it is often in a relatively extreme hydrogen production environment (such as current density higher than 1A·cm -2 , operating temperature of about 55°C, etc.), resulting in many non-precious metal catalysts with excellent activity being unable to be truly used in membrane electrode devices. Therefore, it is urgent to develop a non-precious metal catalyst that can maintain excellent activity and durability under real working conditions. Summary of the invention

[0005] The present invention is directed to the above problems and provides a method for preparing a self-supporting oxygen-containing bimetallic Prussian blue analogue and its application as an oxygen evolution catalytic material in a water electrolysis reaction.

[0006] The present invention is a pioneering and simple method of using oxygen plasma treatment, using cheap non-precious metals to synthesize bimetallic oxygen-containing Prussian blue analogs, which grow evenly and firmly, have the possibility of large-scale production in batches, and meet the preparation and application conditions of commercial water electrolysis electrodes. Further, the present invention treats traditional Prussian blue analogs by oxygen plasma to bombard CN ligands and introduce oxygen atoms to form self-supporting oxygen-containing bimetallic Prussian blue analogs with special Co-O-Fe active structures. First, a CoFe bimetallic Prussian blue analog (CoFe-PBA) is preferentially prepared as a catalyst precursor using a simple and effective coprecipitation method using cheap non-precious metals, and then it is bombarded by oxygen plasma in a pioneering manner, and oxygen atoms are introduced while removing cyano ligands to achieve the preparation of Co-O-Fe local active structures. The self-supporting catalyst obtained by this method grows evenly and firmly, has the possibility of large-scale production in batches, has low preparation costs, short reaction cycles, and high repeatability. At the same time, thanks to the introduction of oxygen atoms, lattice oxygen can be successfully activated, overcoming the overpotential limitation caused by the traditional adsorbate precipitation mechanism, achieving ultra-high oxygen evolution activity and stability at industrial ampere-level current density, and having the possibility of large-scale batch production, which meets the preparation and application conditions of commercial water electrolysis electrodes.

[0007] The constructed self-supporting oxygen-containing bimetallic Prussian blue analogue was used as the anode catalyst of the water electrolysis hydrogen production system, successfully realizing the unique double exchange interaction between Co and Fe atoms. While the lattice oxygen participates in the activation reaction, it can also ensure the stability of the active sites in the catalytic process, thereby overcoming the high overpotential limitation brought by the oxygen evolution reaction. In the future, using it as the anode electrode for commercial alkaline water hydrogen production can promote the transformation of the alkaline water electrolysis hydrogen production industry and reduce the cost of hydrogen production. It not only provides a strategy for the development of efficient electrocatalysts, but also deepens the understanding of the origin of the activity and reaction pathway of oxygen evolution catalysts, and also provides a prerequisite for the development of the next generation of high-performance alkaline water splitting membrane electrode hydrogen production systems.

[0008] In order to achieve the above object, the technical solutions specifically adopted by the present invention are as follows:

[0009] In a first aspect, the present invention provides a method for preparing a self-supporting oxygen-containing bimetallic Prussian blue analog electrocatalyst, comprising the following steps:

[0010] (1) Cobalt chloride hexahydrate is dissolved in deionized water to prepare a 2 mol / L cobalt chloride hexahydrate aqueous solution as solution A; and a certain amount of potassium ferricyanide reagent is weighed at a ratio of 2:1 to the molar ratio of cobalt chloride hexahydrate, which is used as reagent B.

[0011] (2) Slowly add reagent B to solution A under light-proof and stirring conditions. After sufficient reaction, place the electrode support substrate in the mixed suspension. The substrate size is 10 cm 2 / 30mL mixed suspension; let stand for aging reaction at 60°C in the dark without any interference for 6 hours.

[0012] (3) The electrode support substrate after the reaction is repeatedly rinsed with deionized water and ethanol, and naturally dried and oxidized in an air environment, thereby obtaining a catalyst precursor (a traditional bimetallic Prussian blue analogue) grown on the electrode support substrate.

[0013] (4) The catalyst precursor was treated with oxygen plasma in the chamber of a radio frequency plasma enhanced chemical vapor deposition (RF-PECVD) system for 30 minutes while maintaining the chamber pressure at 50 Pa and the RF plasma discharge power at 200 W to obtain a self-supporting oxygen-containing bimetallic Prussian blue analog electrocatalyst named PBA-30.

[0014] Wherein, the electrode supporting substrate is selected from nickel foam or carbon paper.

[0015] In a second aspect, the present invention provides a self-supporting oxygen-containing bimetallic Prussian blue analog electrocatalyst, which is prepared by the above method.

[0016] The results of X-ray diffraction analysis show that after oxygen plasma treatment, the self-supporting oxygen-containing bimetallic Prussian blue analogue still maintains the same lattice structure as the traditional bimetallic Prussian blue analogue, but the diffraction peak shifts to a higher angle. This is because the introduction of smaller ionic oxygen elements causes the lattice of the Prussian blue analogue to be distorted.

[0017] Transmission electron microscopy analysis results show that the prepared self-supporting oxygen-containing bimetallic Prussian blue analogue maintains the CoFe-PBA lattice, which is consistent with the conclusion obtained by X-ray diffraction analysis, indicating that plasma treatment does not destroy the lattice structure of the Prussian blue analogue.

[0018] The ratio of cobalt and iron elements in the self-supporting oxygen-containing bimetallic Prussian blue analogue electrocatalyst (PBA-30) and the traditional bimetallic Prussian blue analogue (PBA-0) before and after the reaction was analyzed. The results showed that the Fe content in the traditional bimetallic Prussian blue analogue after the reaction was almost negligible, indicating that the Fe element was dissolved during the reaction. In contrast, the self-supporting oxygen-containing bimetallic Prussian blue analogue electrocatalyst can still maintain the presence of the Fe element after the reaction, inhibiting the dissolution and disappearance of the Fe element.

[0019] Electrochemical performance test: The prepared self-supporting oxygen-containing bimetallic Prussian blue analogue (electrode area 1×1 cm 2) as the working electrode, silver-silver chloride electrode as the reference electrode, platinum mesh electrode as the counter electrode, the test temperature was 15-25°C, and the test was carried out in an H-type electrolytic cell. The results showed that only an extremely low overpotential of 276mV was required to drive 1000mA·cm -2 The ampere-level current density is nearly 100 mV lower than the overpotential (378 mV) of traditional bimetallic Prussian blue analogs at the same current density.

[0020] It was prepared into anion exchange membrane coupled hydrogen production anode electrode material, and a full battery test was carried out in anion exchange membrane alkaline water electrolyzer to simulate the industrial water electrolysis environment. The results showed that compared with the traditional commercial precious metal iridium oxide catalyst (1.97V), only about 1.76V of battery voltage was required to reach 1000mA·cm -2 , and has good catalyst stability: at up to 1000mA·cm -2 It exhibits excellent stability for over 200 hours at a current density of 1.5 Å, and the potential decay is almost negligible.

[0021] Therefore, the third aspect of the present invention provides the use of the above self-supporting oxygen-containing bimetallic Prussian blue analog electrocatalyst in the preparation of an electrolytic oxygen evolution electrode.

[0022] In a fourth aspect, the present invention provides an electrolytic oxygen-splitting anode electrode, comprising an anode carrier and a catalyst material loaded thereon, wherein the catalyst material is a self-supporting oxygen-containing bimetallic Prussian blue analog electrocatalyst prepared by any of the methods described above.

[0023] In a fifth aspect, the present invention provides a method for electrolyzing water, using the above-mentioned electrolytic oxygen-decomposing anode electrode as an anode.

[0024] Preferably, the electrolyte is 1M KOH solution.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] (1) The catalyst of the present invention uses cheap cobalt salt and potassium ferrocyanide as main raw materials, and all reagents are commercial products and do not require further processing, thereby reducing the preparation cost of the electrode;

[0027] (2) The synthesis process of the self-supporting oxygen-containing bimetallic Prussian blue analog electrocatalyst is simple, the reaction conditions are mild, and the preparation cycle is short. By adjusting the amount of synthesis liquid, the electrode size ratio can be customized and adjusted, which meets the conditions for large-scale production of commercial electrolytic hydrogen production electrodes;

[0028] (3) The prepared self-supporting oxygen-containing bimetallic Prussian blue analog electrocatalyst can achieve 1000 mA cm-2 in the electrolytic oxygen evolution reaction of water in alkaline electrolyte with an overpotential of only 276 mV. 2 The current density can be kept stable for 400h without potential decay. In addition, the anion exchange membrane electrolyzer hydrogen production system based on oxygen-containing bimetallic Prussian blue analogues as anode catalyst can achieve 1000mA·cm at only 1.76V. 2 The industrial-grade current density can reduce the energy consumption of hydrogen production by nearly 200mV compared with the traditional noble metal iridium oxide catalyst as the anode, while reducing the cost of hydrogen production and the cost of raw materials while maintaining excellent hydrogen production stability. This shows that the prepared self-supporting oxygen-containing bimetallic Prussian blue analog electrocatalyst has good catalytic activity, is suitable for the use environment of high current density of commercial water electrolysis, and can be effectively used in industrial operating environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is an X-ray diffraction analysis diagram of the product prepared in Example 1;

[0030] Figure 2 is a high-resolution transmission electron microscope of the product prepared in Example 1;

[0031] Figure 3 This is the analysis of the proportion of cobalt and iron elements in the product prepared in Example 1 before and after the reaction;

[0032] Figure 4 The R space spectrum of the in-situ cobalt element of the product prepared in Example 1 at different potentials and the R space spectrum of the standard cobalt foil;

[0033] Figure 5 This is the linear scanning curve of the product prepared in Example 1 directly used as the working electrode in an alkaline electrolyte;

[0034] Figure 6 The product prepared in Example 1 was directly used as the working electrode in an alkaline electrolyte at a constant current (1000 mA·cm 2 ) Long-term stability test chart;

[0035] Figure 7 It is an anion exchange membrane alkaline water electrolyzer device for full battery testing of the product prepared in Example 1;

[0036] Figure 8 It is a linear scanning curve of the product prepared in Example 1 in a full-cell test in an anion exchange membrane alkaline water electrolyzer;

[0037] Fig. 9 This is a stability test curve of the product prepared in Example 1 in a full battery test in an anion exchange membrane alkaline water electrolyzer. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solution and advantages of the embodiment of the present invention clearer, the technical solution of the embodiment of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all of the embodiments. Based on the described embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0039] The "range" disclosed herein is in the form of a lower limit and an upper limit. It can be one or more lower limits, and one or more upper limits, respectively. A given range is defined by selecting a lower limit and an upper limit. The selected lower limit and upper limit define the boundaries of a particular range. All ranges that can be defined in this way are inclusive and combinable, i.e., any lower limit can be combined with any upper limit to form a range. For example, a range of 100 to 140 and 500 to 900 is listed for a particular parameter, and it is understood that a range of 100 to 140 and 500 to 900 is also expected. In addition, if the minimum range values ​​1 and 2 are listed, and if the maximum ranges 3, 4 and 5 are listed, the following ranges can all be expected: 1 to 2, 1 to 4, 1 to 5, 2 to 3, 2 to 4 and 2 to 5.

[0040] In the present invention, unless otherwise specified, the numerical range "a-b" represents an abbreviation of any real number combination between a and b, where a and b are real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" are listed in this document, and "0-5" is just an abbreviation of these numerical combinations.

[0041] In the present invention, unless otherwise specified, all embodiments and preferred embodiments mentioned herein can be combined with each other to form a new technical solution.

[0042] Example 1

[0043] 1. Preparation of self-supported oxygen-containing bimetallic Prussian blue analogue electrocatalysts

[0044] (1) dissolving cobalt chloride hexahydrate in deionized water to prepare a cobalt chloride hexahydrate aqueous solution with a concentration of 2 mol / L as solution A;

[0045] (2) At the same time, a certain amount of potassium ferricyanide reagent is weighed, and the weight weighed is in a molar ratio of 2:1 to the amount of cobalt chloride hexahydrate used in solution A, and is used as reagent B;

[0046] (3) Slowly add reagent B to solution A under light-proof and stirring conditions. After sufficient reaction, place the electrode support substrate in the mixed suspension. The substrate size is 10 cm 2 / 30mL mixed suspension, let stand for aging reaction at 60℃ in the dark without any interference for 6 hours;

[0047] (4) The electrode support substrate after the reaction is repeatedly rinsed with deionized water and ethanol, and naturally dried and oxidized in an air environment, thereby obtaining a catalyst precursor (a traditional bimetallic Prussian blue analogue) grown on the electrode support substrate;

[0048] (5) The catalyst precursor was continuously treated with oxygen plasma in the chamber of a radio frequency plasma enhanced chemical vapor deposition (RF-PECVD) system for 30 minutes, while maintaining the chamber pressure at 50 Pa and the RF plasma discharge power at 200 W to obtain a self-supporting oxygen-containing bimetallic Prussian blue analog electrocatalyst.

[0049] 2. Performance Characterization Test

[0050] Figure 1 The X-ray diffraction analysis diagram of the prepared self-supporting oxygen-containing bimetallic Prussian blue analogue electrocatalyst and the traditional bimetallic Prussian blue analogue is shown. It can be seen that after oxygen plasma treatment, the self-supporting oxygen-containing bimetallic Prussian blue analogue still maintains the lattice structure of the traditional bimetallic Prussian blue analogue, but the diffraction peak shifts to a higher angle. This is because the introduction of smaller ionic oxygen elements causes the lattice of the Prussian blue analogue to be distorted.

[0051] Figure 2 This is a high-resolution transmission electron microscopy of the prepared self-supporting oxygen-containing bimetallic Prussian blue analogue electrocatalyst. It can be seen that the self-supporting oxygen-containing bimetallic Prussian blue analogue maintains the lattice of CoFe-PBA, which is consistent with the conclusion obtained by X-ray diffraction analysis, indicating that plasma treatment does not destroy the lattice structure of the Prussian blue analogue.

[0052] Figure 3 The cobalt and iron content of the prepared self-supporting oxygen-containing bimetallic Prussian blue analogue electrocatalyst (PBA-30) and the traditional bimetallic Prussian blue analogue (PBA-0) before and after the reaction is analyzed. It can be seen that the Fe content of the traditional bimetallic Prussian blue analogue after the reaction is almost negligible, indicating that the Fe element is dissolved during the reaction. In contrast, the self-supporting oxygen-containing bimetallic Prussian blue analogue electrocatalyst can still maintain the presence of the Fe element after the reaction, inhibiting the dissolution and disappearance of the Fe element.

[0053] Figure 4The R-space spectrum of the in-situ cobalt element of the prepared self-supporting oxygen-containing bimetallic Prussian blue analog electrocatalyst at different potentials and the R-space spectrum of the standard cobalt foil. The microscopic coordination information of the product can be qualitatively analyzed by Fourier transforming the extended edge of the X-ray absorption fine structure spectrum. Among them: Curve 1 is the curve of the standard cobalt foil; Curve 2 is the curve of the self-supporting oxygen-containing bimetallic Prussian blue analog prepared in Example 1 at the open circuit potential; Curve 3 is the curve of the prepared self-supporting oxygen-containing bimetallic Prussian blue analog at a test potential of 1.55V; Curve 4 is the curve of the prepared self-supporting oxygen-containing bimetallic Prussian blue analog at a test potential of 1.65V.

[0054] according to Figure 4 It can be seen that the intensity of the Fe-C coordination peak tends to decrease after the potential increases, and then remains stable. This may be due to the instability of the -CN group at the beginning of the reaction, but the local coordination structure around Fe has not undergone any essential changes. This further proves that the coordination structure around the Fe element of the oxygen-containing bimetallic Prussian blue analogue electrocatalyst is stable during the oxygen evolution reaction, thereby ensuring that it is not easily dissolved, thereby ensuring catalytic stability.

[0055] 3. Electrochemical performance test

[0056] The prepared oxygen-containing bimetallic Prussian blue analogue was directly used as the working electrode for electrochemical characterization test. The prepared oxygen-containing bimetallic Prussian blue analogue electrode was placed in 1.0M KOH aqueous solution using a CHI760 electrochemical workstation and a standard three-electrode system, and the linear scan test and cycle performance test were performed using conventional methods.

[0057] Specifically, in a conventional environment of water electrolysis for hydrogen production, i.e., a 1 mol potassium hydroxide (1.0 M KOH) aqueous solution is used as the electrolyte solution, the self-supporting oxygen-containing bimetallic Prussian blue analog (electrode area of ​​1×1 cm 2 ) was used as the working electrode, the silver-silver chloride electrode was used as the reference electrode, the platinum mesh electrode was used as the counter electrode, the test temperature was 15-25°C, and the test was carried out in an H-type electrolytic cell.

[0058] Figure 5The linear scanning curve of the self-supporting oxygen-containing bimetallic Prussian blue analogue prepared above directly as a working electrode in an alkaline electrolyte is shown. Wherein: Curve 1 is a linear scanning curve under the test conditions of the prepared self-supporting oxygen-containing bimetallic Prussian blue analogue as a working electrode, a silver-silver chloride electrode as a reference electrode, a platinum mesh as a counter electrode, a 1.0M KOH aqueous solution as an electrolyte, a test temperature of 15-25°C and a scanning speed of 5mV / s; Curve 2 is a linear scanning curve under the test conditions of the traditional bimetallic Prussian blue analogue as a working electrode, a silver-silver chloride electrode as a reference electrode, a platinum mesh as a counter electrode, a 1.0M KOH aqueous solution as an electrolyte, a test temperature of 15-25°C and a scanning speed of 5mV / s.

[0059] Depend on Figure 5 As far as we know, the self-supported oxygen-containing bimetallic Prussian blue analogues show better OER performance than traditional bimetallic Prussian blue analogues. -2 The overpotential at a current density of only 218 mV (the traditional bimetallic Prussian blue analog is 258 mV). More notably, the self-supported oxygen-containing bimetallic Prussian blue analog exhibits exciting catalytic performance at high current density: only an extremely low overpotential of 276 mV is required to drive 1000 mA cm -2 The current density is much lower than the 378 mV overpotential required for traditional bimetallic Prussian blue analogs.

[0060] Figure 6 The stability test results are shown. The prepared self-supporting oxygen-containing bimetallic Prussian blue analogue was directly used as the working electrode, the silver-silver chloride electrode was used as the reference electrode, the platinum mesh was used as the counter electrode, the 1.0M KOH aqueous solution was used as the electrolyte, and the test temperature was room temperature. The constant current (1000mA·cm -2 ) for a long time. During the 400-hour test, the potential did not rise, indicating that the catalytic activity did not decay.

[0061] 3. Membrane electrode test simulation

[0062] In an anion exchange membrane alkaline water electrolyzer, a full cell test was conducted to simulate the industrial water electrolysis environment. 1.0M KOH aqueous solution was used as the electrolyte solution, the prepared self-supporting oxygen-containing bimetallic Prussian blue analogue was used as the anode electrode, and commercial Pt / C (20wt%) was sprayed on the gas diffusion layer (GDE) as the cathode electrode, and the full cell performance test was conducted at a temperature of 55°C. Figure 7 A schematic diagram of the full-cell test device and internal structure of the anion exchange membrane alkaline water electrolyzer is shown.

[0063] Figure 8The linear scanning curves of the full-cell test in the anion exchange membrane alkaline water electrolyzer are shown in Figure 1. Curve 1 is the test curve of the anion exchange membrane electrolysis hydrogen production device with the prepared self-supporting oxygen-containing bimetallic Prussian blue analog as the anode electrode and commercial Pt / C (20wt%) sprayed on the gas diffusion layer (GDE) as the cathode electrode; Curve 2 is the test curve of the anion exchange membrane electrolysis hydrogen production device with the prepared commercial iridium oxide catalyst sprayed on the gas diffusion layer (GDE) as the anode electrode and commercial Pt / C (20wt%) sprayed on the gas diffusion layer (GDE) as the cathode electrode.

[0064] Depend on Figure 8 It can be seen that in an anion exchange membrane alkaline water electrolyzer, compared with the traditional commercial precious metal iridium oxide catalyst (1.97V), only about 1.76V of battery voltage is required to reach 1000mA·cm -2 , with excellent catalytic activity.

[0065] Fig. 9 The stability test curve of the anion exchange membrane electrolysis hydrogen production device is shown in Figure 2, which uses the prepared self-supporting oxygen-containing bimetallic Prussian blue analog as the anode electrode and commercial Pt / C (20wt%) sprayed on the gas diffusion layer (GDE) as the cathode electrode. Fig. 9 It can be seen that the new anion exchange membrane electrolysis hydrogen production system constructed with the prepared self-supporting oxygen-containing bimetallic Prussian blue analog as the anode electrode has a high conductivity at up to 1000 mA cm -2 It exhibits excellent stability for over 200 hours at a current density of 2.5 Å, and the potential decay is almost negligible, which indicates the excellent hydrogen production stability of the hydrogen production system.

[0066] The preferred embodiments of the present invention have been specifically described above, but the present invention is not limited to the embodiments. Those skilled in the art may make various equivalent modifications or substitutions without violating the spirit of the present invention. These equivalent modifications or substitutions are all included in the scope defined by the claims of this application.

Claims

1. A method for preparing a self-supporting oxygen-containing bimetallic Prussian blue analog electrocatalyst, characterized in that: The steps include: A cobalt precursor is prepared into solution A, and potassium ferrocyanide is weighed as a coprecipitant and named as reagent B; reagent B is slowly added to solution A under light-proof and stirring conditions, and a mixed suspension C is obtained after sufficient reaction; then an electrode support substrate of a certain proportion is placed in the above-mentioned mixed suspension C, and allowed to stand for aging in the dark, and after rinsing and drying, a catalyst precursor D grown on the electrode support substrate is obtained; finally, the precursor D is continuously treated with oxygen plasma for a certain period of time to obtain a self-supporting oxygen-containing bimetallic Prussian blue analogue electrocatalyst.

2. The preparation method according to claim 1, characterized in that: in, The preparation method of solution A is as follows: dissolving cobalt chloride hexahydrate in deionized water to prepare a cobalt chloride hexahydrate aqueous solution with a concentration of 2 mol / L as solution A; The molar ratio between potassium ferrocyanide and cobalt chloride hexahydrate is 2:

1.

3. The preparation method according to claim 2, characterized in that: in, The ratio between the electrode support substrate and the mixed suspension C is 10 cm 2 Base / 30mL mixed suspension C; The static aging conditions are: static aging reaction for 6 hours at 60°C in dark conditions without any interference, repeatedly rinsing the electrode support substrate after the reaction with deionized water and ethanol, and naturally drying and oxidizing in an air environment to obtain a catalyst precursor D grown on the electrode support substrate.

4. The preparation method according to claim 2, characterized in that: in, The electrode support substrate is selected from nickel foam or carbon paper.

5. The preparation method according to claim 1, characterized in that: in, The method for treating precursor D with oxygen plasma is as follows: the catalyst precursor is continuously treated with oxygen plasma in the chamber of a radio frequency plasma enhanced chemical vapor deposition system for 30 minutes, while maintaining the chamber pressure at 50 Pa and the radio frequency plasma discharge power at 200 W to obtain a self-supporting oxygen-containing bimetallic Prussian blue analog electrocatalyst.

6. A self-supporting oxygen-containing bimetallic Prussian blue analog electrocatalyst, characterized in that: The method is prepared by any one of claims 1 to 5.

7. Use of the self-supporting oxygen-containing bimetallic Prussian blue analog electrocatalyst according to claim 6 in the preparation of an electrolytic oxygen evolution electrode.

8. An electrolytic oxygen anode electrode, characterized in that: It comprises an anode carrier and a catalyst material loaded thereon, wherein the catalyst material is an ethylene glycol electro-oxidation catalyst prepared by the method according to any one of claims 1 to 5.

9. A method for electrolyzing water, characterized in that: The electrolytic oxygen-splitting anode electrode according to claim 8 is used as the anode.

10. The method for electrolyzing water according to claim 9, characterized in that: in, The electrolyte was 1 M KOH solution.

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