A method for preparing an oxygen evolution electrode

Abstract

The present application relates to the technical field of hydrogen production by electrolysis of water, and in particular to a method for preparing an oxygen evolution electrode. The preparation method comprises: selecting stainless steel and titanium nickel as a base mesh substrate, and cleaning the mesh substrate; placing the mesh substrate and the target material into a vacuum chamber, and introducing a protective gas and a reaction gas into the vacuum chamber, applying a deposition current and a deposition bias, and using the target material to deposit on the mesh substrate to form a bottom layer; gradually increasing the deposition current, gradually reducing the deposition bias, and using the target material to deposit on the bottom layer to form a catalytic layer to obtain an oxygen evolution electrode; moving the oxygen evolution electrode into a reaction chamber, and introducing a reaction medium into the reaction chamber to etch the catalyst layer so that the catalyst layer has a porous network. This method adjusts the current and bias during the deposition process to adjust the growth orientation of the catalytic material, forming a dense and intricate network of branches, so as to enhance the bonding force between the catalytic layer and the mesh substrate, and also enhance the specific surface area of ​​the oxygen evolution electrode.

Description

Technical Field

[0001] The present application relates to the technical field of hydrogen production by electrolysis of water, and in particular to a method for preparing an oxygen evolution electrode. Background Art

[0002] Hydrogen energy can be widely used in methanol production, oil hydrogenation, synthetic ammonia, metal smelting, heating and vehicle transportation, etc. The total amount of renewable energy is increasing significantly and will become one of the main energy sources. Its power generation cost is decreasing with the maturity of technology and the expansion of scale. Renewable energy hydrogen production is expected to have market competitiveness.

[0003] At present, the anode in the electrolyzer is mainly MEA (catalyst coated on membrane electrode) solution, there is no efficient oxygen evolution electrode, and most of the preparations are made by chemical immersion or electroplating process, electroplating a layer of nickel-iron material on the surface of the porous diffusion layer. The bonding strength is low, and powder often falls off during short-term operation, and the catalytic performance decays significantly. Summary of the invention

[0004] The embodiment of the present application provides a method for preparing an oxygen evolution electrode, which aims to prepare the oxygen evolution electrode by a vacuum deposition process to improve the film bonding strength and material stability.

[0005] The present application provides a method for preparing an oxygen evolution electrode, the preparation method comprising:

[0006] S1: cleaning the mesh substrate;

[0007] S2: placing the mesh substrate and the target material into a vacuum chamber, introducing a protective gas and a reaction gas into the vacuum chamber, applying a deposition current and a deposition bias, and using the target material to deposit on the mesh substrate to form a bottom layer;

[0008] S3: gradually increasing the deposition current, gradually reducing the deposition bias voltage, and using the target material to deposit on the bottom layer to form a catalytic layer, thereby obtaining the oxygen evolution electrode;

[0009] S4: moving the oxygen evolution electrode into a reaction chamber, introducing a reaction medium into the reaction chamber to etch the catalyst layer, so that the catalyst layer has a porous network.

[0010] In a possible design, the material of the mesh substrate includes at least one of a titanium mesh, a stainless steel mesh, and a nickel mesh.

[0011] In a possible design, in step S2, the protective gas and the reaction gas are O 2 and Ar.

[0012] In a possible design, in step S2, the target material is deposited on the surface of the mesh substrate by a physical vapor deposition process or an electroplating impact process to form the bottom layer.

[0013] In a possible design, the target material includes at least one of a titanium target material, a nickel target material, an iron target material, a nickel-iron alloy target material, a stainless steel target material, and an iron-cobalt alloy target material.

[0014] In a possible design, the material of the bottom layer includes one or more combinations of metals of nickel, titanium, and aluminum and alloy oxide materials thereof.

[0015] In a possible design, in step S3, the deposition current is gradually increased from 5A to 12A, and the deposition voltage is gradually decreased from 1500V to 120V.

[0016] In one possible design, in step S4, the reaction medium is H 2 Or Ar or alkaline solution.

[0017] In a possible design, the main element of the catalytic layer is Ni-Fe-Ox, and the ratio of Fe atoms to the total Ni-Fe atoms is 20%-40%;

[0018] The doping element of the catalytic layer includes at least one of Co, Mn and Cr, and the proportion of atoms of the doping element to total atoms is 15%-30%.

[0019] In a possible design, the thickness of the oxygen evolution electrode is 300nm-500nm.

[0020] In one possible design, the specific surface area of ​​the oxygen evolution electrode is greater than 100 m 2 / g.

[0021] In a possible design, the surface contact angle of the oxygen evolution electrode is less than 40°.

[0022] In a second aspect, an embodiment of the present application further provides an oxygen evolution electrode, which is prepared by the method described above, and the oxygen evolution electrode comprises a mesh substrate, a bottom layer and a catalytic layer in an integrated structure.

[0023] In a third aspect, the present application further provides an electrolytic cell, which comprises the oxygen evolution electrode described above.

[0024] It should be understood that the foregoing general description and the following detailed description are exemplary only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A schematic diagram of the process for preparing an oxygen evolution electrode provided in this application;

[0026] Figure 2 This is a cross-sectional schematic diagram of the oxygen evolution electrode provided in this application;

[0027] Figure 3 This is an electron scanning microscope image of the oxygen evolution electrode surface provided in this application;

[0028] Figure 4 This is a test diagram showing the hydrophilicity of the oxygen evolution electrode provided in this application;

[0029] Figure 5 A comparison diagram of polarity curves of Example 1, Example 4 and a comparative example (untreated porous diffusion layer) provided in the present application;

[0030] Figure 6 This is a schematic diagram of the change in voltage required for electrolyzing water in the electrolytic cell provided in this application over time.

[0031] Reference numerals:

[0032] 1- oxygen evolution electrode;

[0033] 11- mesh substrate;

[0034] 12- bottom floor;

[0035] 13-Catalytic layer.

[0036] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application. DETAILED DESCRIPTION

[0037] In order to better understand the technical solution of the present application, the embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0038] It should be clear that the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0039] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a", "said" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0040] It should be understood that the term "and / or" used in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0041] It should be noted that the directional words such as "upper", "lower", "left", and "right" described in the embodiments of the present application are described at the angles shown in the accompanying drawings and should not be understood as limiting the embodiments of the present application. In addition, in the context, it is also necessary to understand that when it is mentioned that an element is connected to another element "upper" or "lower", it can not only be directly connected to another element "upper" or "lower", but also indirectly connected to another element "upper" or "lower" through an intermediate element.

[0042] With the increasing global attention to environmental protection and decarbonization and the advancement of renewable energy power generation technology, the use of renewable energy such as wind, electricity, light, photovoltaics, and hydropower to produce hydrogen is an important way to achieve a green hydrogen economy. Hydrogen energy can be widely used in methanol production, oil hydrogenation, synthetic ammonia, metal smelting, heating, and automotive transportation. The total amount of renewable energy is growing significantly and will become one of the main energy sources. Its power generation cost is constantly decreasing with the expansion of technology and scale. Renewable energy hydrogen production is expected to be competitive in the market. In addition, renewable energy hydrogen production can absorb abandoned wind, abandoned light, and abandoned hydropower to obtain low-cost hydrogen.

[0043] Water electrolysis hydrogen production technology includes alkaline water electrolysis hydrogen production, proton exchange membrane (PEM) water electrolysis hydrogen production, alkaline anion exchange membrane (AEM) water electrolysis hydrogen production and solid oxide water electrolysis hydrogen production.

[0044] Among them, alkaline water electrolysis hydrogen production technology is the most mature. The technology has the advantages of low equipment cost, long life and robustness, and is suitable for large-scale production of green hydrogen. However, it has the disadvantages of low current density and high electrolysis energy consumption. In addition, due to the thicker diaphragm and greater resistance in the alkaline electrolyzer, the hydrogen production efficiency is relatively low and the hydrogen purity is low. De-alkali mist treatment is required to improve the hydrogen purity.

[0045] The proton exchange membrane in PEM water electrolysis hydrogen production is very thin and has low resistance. It can withstand large currents under high efficiency, making hydrogen production more efficient. However, PEM electrolyzers need to operate in a highly acidic and highly oxidizing working environment, and have high material requirements. They are more dependent on expensive metal materials such as iridium, platinum, and titanium, resulting in high costs.

[0046] AEM combines the advantages of traditional alkaline liquid electrolyte water electrolysis and PEM water electrolysis. It can use non-precious metal catalysts in alkaline media to reduce equipment and material costs. However, AEM water electrolysis technology is still in the experimental product stage, and the thermal and chemical stability of the oxygen evolution electrode is poor. Therefore, it is particularly important to develop an AEM electrolyzer anode oxygen evolution electrode and its preparation method.

[0047] In the AEM electrolyzer, the GDE (Gas diffusion electrode) scheme and the CCM (catalyst-coated membrane) scheme are two different AEM preparation technologies. The CCM scheme is to deposit the catalyst directly on the ion membrane to form a catalyst coating membrane. This scheme can be achieved through the catalyst coating membrane (CCM) technology, that is, the catalyst powder and ionomer are mixed with a suitable solvent and directly coated on the membrane. The preparation process is relatively complicated and requires precise control of the coating amount and uniformity of the catalyst. The stability of the membrane may be affected by the catalyst deposition process. The GDE scheme usually deposits the catalyst on a gas diffusion layer (GDL) or a porous transport layer (PTL). The preparation process is relatively simple and easy to achieve large-scale production. In addition, the GDE scheme improves the rate and efficiency of water electrolysis and the effective utilization of catalysts by optimizing the electrode structure and uniformly distributing and transmitting the protective gas.

[0048] In current technology, most oxygen evolution electrodes are prepared by chemical immersion or electroplating process, in which a layer of nickel-iron material is electroplated on the surface of the porous diffusion layer. The bonding strength is low, and powder loss often occurs during short-term operation, and the catalytic performance is significantly attenuated.

[0049] The MEA solution uses a catalyst composited onto an anion exchange membrane. The polymer membrane has large swelling and shrinkage changes in an alkaline environment, the catalyst is very easy to fall off, and the performance decays significantly.

[0050] Compared with conventional oxygen evolution electrodes and MEA solutions, the contact resistance between the membrane and the catalyst is increased, the ohmic internal resistance is significantly increased, and the overall performance is significantly degraded.

[0051] The surface of the oxygen evolution electrode was prepared without hydrophilicity adjustment, so a stable gas-solid-liquid three-phase interface was constructed to suppress electrolyte overflow and gas transmission problems under high current density.

[0052] To this end, this embodiment provides a method for preparing an oxygen evolution electrode to solve the above technical problems.

[0053] like Figure 1 The figure shows a schematic diagram of a process for preparing an oxygen evolution electrode, wherein the preparation method comprises:

[0054] S1: Selecting a mesh substrate 11 and cleaning the mesh substrate 11;

[0055] S2: placing the mesh substrate 11 and the target material into a vacuum chamber, introducing a protective gas and a reaction gas into the vacuum chamber, applying a deposition current and a deposition bias, and using the target material to deposit on the mesh substrate 11 to form a bottom layer 12;

[0056] S3: gradually increasing the deposition current, gradually reducing the deposition bias voltage, and using the target material to deposit a catalytic layer 13 on the bottom layer 12 to obtain an oxygen evolution electrode 1;

[0057] S4: The oxygen evolution electrode 1 is moved into a reaction chamber, and a reaction medium is introduced into the reaction chamber to etch the catalyst layer, so that the catalyst layer 13 has a porous network.

[0058] Specifically, the material of the mesh substrate 11 includes at least one of a titanium mesh, a stainless steel mesh, and a nickel mesh. The mesh substrate can also be made of other materials, which can be set according to actual conditions, and this embodiment is not limited thereto. Before placing the mesh substrate 11 in the vacuum chamber, the mesh substrate 11 can be cleaned. For example, the mesh substrate 11 can be placed in ethanol and water for ultrasonic cleaning to remove grease and debris on the surface of the mesh substrate 11.

[0059] Then, the mesh substrate 11 is placed in the vacuum chamber, and the target is placed in the vacuum chamber, and the distance between the target and the mesh substrate 11 is set between 4 cm and 8 cm. The target includes at least one of a titanium target, a nickel target, an iron target, a nickel-iron alloy target, a stainless steel target, and an iron-cobalt alloy target. Alternatively, the target can also be made of other materials, which can be set according to actual conditions, and this embodiment is not limited here.

[0060] Introduce reactive gases and protective gases, such as Ar and O, into the vacuum chamber. 2 , so that the target reacts with oxygen to generate oxides. Among them, the protective gas can also be selected from other gases, which can be set according to actual conditions, and this embodiment does not limit it here.

[0061] The target material is deposited on the surface of the mesh substrate 11 by a physical vapor deposition process or an electroplating impact process to form a bottom layer 12. The physical vapor deposition process includes but is not limited to magnetron sputtering, evaporation, multi-arc ion plating and other processes.

[0062] Taking the magnetron sputtering process as an example, during the magnetron sputtering process, electrons fly toward the mesh substrate 11 under the action of the electric field. In the process of flying toward the mesh substrate 11, the electrons collide with argon atoms, ionizing them to produce argon positive ions and new electrons. New electrons fly toward the mesh substrate 11 under the action of the electric field, and argon positive ions fly toward the target material under the action of the electric field, and bombard the surface of the target material with high energy, causing the target material to sputter. The atoms or molecules on the surface of the target material break away from the surface of the target material and deposit on the surface of the mesh substrate 11 to form a bottom layer 12. Among them, the material of the bottom layer 12 includes, but is not limited to, metals of nickel, titanium, and aluminum elements and their alloy oxide materials, and the bottom layer 12 is one or more combinations thereof.

[0063] Specifically, before depositing the bottom layer 12, the vacuum chamber may be evacuated to 5 10 ﹣3 pa, turn on the heater to heat to 300°C, keep warm for a while, and then introduce Ar and O into the vacuum chamber. 2 The sputtering gas pressure was controlled at 2 Pa. At a deposition temperature of 300° C., the deposition current was controlled at 5 A, the deposition time was 10 min, and the deposition bias was 1500 V, and a metal bottom layer 12 was deposited.

[0064] Continue to deposit on the bottom layer 12, and gradually increase the deposition current, gradually reduce the deposition bias, and use the target material to deposit on the bottom layer 12 to form a catalytic layer 13 to obtain an oxygen evolution electrode 1. For example, the deposition current can be gradually increased from 5A to 12A, and the deposition bias can be gradually reduced from 1500V to 120V. With the increase of the deposition current and the decrease of the deposition voltage, the mechanical properties such as the deposition rate and the hardness of the film are improved to a certain extent. In this embodiment, the growth orientation of the catalytic material is adjusted by adjusting the current and bias during the deposition process to form a dense and intricate network to enhance the bonding force between the catalytic layer 13 and the mesh substrate 11, while also increasing the specific surface area of ​​the oxygen evolution electrode 1.

[0065] Of course, in this step, when different materials of the target are used, the applied deposition current, deposition voltage and deposition time are all different, and the obtained oxygen evolution electrode 1 (the elements contained therein) are also different.

[0066] Exemplarily, in the process of continuing to deposit the catalytic layer 13 on the bottom layer 12, when the target material is a titanium target or a nickel-iron alloy target, at a deposition temperature of 300°C, the deposition current of the titanium target and the nickel-iron alloy target is controlled to be 5A, the deposition time is 10min, and the deposition bias is 1200V. Then, at a deposition temperature of 300°C, the deposition current of the titanium target and the nickel-iron alloy target is controlled to be 10A, the deposition time is 30min, and the deposition bias is 500V. Finally, at a deposition temperature of 300°C, the deposition current of the titanium target and the nickel-iron alloy target can be controlled to be 10A, the deposition time is 30min, and the deposition bias is 500V. After the deposition is completed, the vacuum chamber is gradually cooled to room temperature to obtain an oxygen evolution electrode 1Ni-Fe-Ox electrode.

[0067] Alternatively, in the process of continuing to deposit the catalytic layer 13 on the bottom layer 12, when the target material is a titanium target, a nickel target and an iron target, at a deposition temperature of 300°C, the deposition current is controlled to be 5A for the nickel target, 3A for the iron target, the deposition time is 15min, and the deposition bias is 1200V. At a deposition temperature of 300°C, the deposition current is controlled to be 10A for the nickel target, 3A for the iron target, the deposition time is 30min, and the deposition bias is 500V. At a deposition temperature of 300°C, the deposition current is controlled to be 12A for the nickel target, 3A for the iron target, the deposition time is 45min, and the deposition bias is 120V. After the deposition is completed, the vacuum chamber is gradually cooled to room temperature to obtain an oxygen evolution electrode 1 oxygen Ni-Fe-Ox electrode.

[0068] Alternatively, in the process of continuing to deposit the catalytic layer 13 on the bottom layer 12, when the target material is a nickel target and a stainless steel (316L) target, at a deposition temperature of 300°C, the deposition current is controlled to be 5A for the nickel target, 2A for the stainless steel target, the deposition time is 10min, and the deposition bias is 1500V. At a deposition temperature of 300°C, the deposition current is controlled to be 10A for the nickel target, 3A for the stainless steel target, the deposition time is 30min, and the deposition bias is 500V. At a deposition temperature of 300°C, the deposition current is controlled to be 12A for the nickel target, 4A for the stainless steel target, the deposition time is 40min, and the deposition bias is 120V. After the deposition is completed, the vacuum chamber is gradually cooled to room temperature to obtain an oxygen evolution electrode 1 oxygen Ni-Fe-Cr-Ox electrode.

[0069] Alternatively, in the process of continuing to deposit the catalytic layer 13 on the bottom layer 12, when the target material is a nickel target and an iron-cobalt alloy target, at a deposition temperature of 300°C, the deposition current is controlled to be 5A for the nickel target, 2A for the iron-cobalt alloy target, the deposition time is 10min, and the deposition bias is 1500V. At a deposition temperature of 300°C, the deposition current is controlled to be 10A for the nickel target, 3A for the iron-cobalt alloy target, the deposition time is 30min, and the deposition bias is 500V. At a deposition temperature of 300°C, the deposition current is controlled to be 12A for the nickel target, 4A for the iron-cobalt alloy target, the deposition time is 40min, and the deposition bias is 120V. After the deposition is completed, the vacuum chamber is gradually cooled to room temperature to obtain an oxygen evolution electrode 1 oxygen Ni-Fe-Co-Ox electrode.

[0070] The thickness of the oxygen evolution electrode 1 may be 300nm-500nm. For example, the thickness of the oxygen evolution electrode 1 may be 300nm, 400nm, 500nm, etc., or the thickness may be further increased or decreased according to the demand, which may be set according to the actual situation, and this embodiment is not limited here.

[0071] The obtained oxygen evolution electrode 1 is transferred into the reaction chamber, and the catalytic layer 13 is etched by the reaction medium in the reaction chamber to make it porous, thereby increasing the specific surface area of ​​the oxygen evolution electrode 1. Figure 2 , as shown in FIG2 , is a schematic cross-sectional view of the oxygen evolution electrode 1 .

[0072] like Figure 3 The electron scanning microscope image of the surface of the oxygen evolution electrode 1 is shown, from which it can be seen that the pore distribution on the surface of the oxygen evolution electrode 1 is shown as a porous structure, so that the oxygen evolution electrode 1 has a high specific surface area.

[0073] In some embodiments, the reaction medium may be H 2 Or Ar or alkaline solution.

[0074] For example, the reaction chamber may be a vacuum environment. After the oxygen evolution electrode 1 is moved to the reaction chamber, the reaction chamber is evacuated to 5 10 ﹣3 pa, and heat the reaction chamber to 600°C and keep it warm for a while. Then, the reaction gas H 2 , control the vacuum to maintain at 0.2 Pa, control the deposition bias to 800 V-1200 V, and the deposition temperature to 600 ° C. The processing time is 60 min.

[0075] Alternatively, the reaction chamber may be in a vacuum environment. After the oxygen evolution electrode 1 is moved to the reaction chamber, the reaction chamber is evacuated to 5 10 ﹣3The reaction chamber was heated to 800°C and kept warm for a period of time. Then, argon gas was introduced into the reaction chamber, the vacuum was controlled to be maintained at 0.01 Pa, the deposition bias was controlled to be 1000 V, and the deposition temperature was 800°C for 30 min.

[0076] Alternatively, 0.1M potassium hydroxide is provided in the reaction chamber, and after the oxygen evolution electrode 1 is moved to the reaction chamber, the potassium hydroxide is heated to 120° C. for 30 minutes, and then taken out and dried.

[0077] In this embodiment, the oxygen evolution electrode 1 obtained by the above preparation method can achieve stable attachment of the catalyst on the substrate surface of the oxygen evolution electrode 1, thereby improving the stability of the oxygen evolution electrode 1. At the same time, through the above preparation method, the oxygen evolution electrode 1 has a hydrophilic surface and a porous structure, which greatly improves the enrichment of reactants on the catalyst surface to produce reactions, greatly reduces the reaction overpotential, and improves the catalytic performance. Furthermore, the above preparation method is simple in process and cost-effective, and is easy to prepare the oxygen evolution electrode 1 on a large scale.

[0078] In some embodiments, the oxygen evolution electrode 1 obtained by the above preparation method has a specific surface area of ​​100 m 2 / g, so that the oxygen evolution electrode 1 has a porous structure, which improves the catalytic efficiency.

[0079] In some embodiments, the oxygen evolution electrode 1 obtained by the above preparation method has a surface contact angle of less than 40°, which improves the hydrophilic effect of the oxygen evolution electrode 1, realizes a gas-solid-liquid three-phase interface, and stabilizes the entry of reactants and the discharge of gases.

[0080] Please refer to Figure 4 , Figure 4 This is a test diagram showing the hydrophilicity of the oxygen evolution electrode 1 of this embodiment. The figure shows that a liquid is dropped on the test surface (the surface of the oxygen evolution electrode 1) to measure the contact angle of the liquid on the test surface. When the contact angle (CA) is above 90°, the test surface is hydrophobic, and when the contact angle (CA) is below 90°, the test surface is hydrophilic.

[0081] It can be seen that in this test, the contact angle (CA) is 22.518°, indicating that the test surface (the surface of the oxygen evolution electrode 1) has good hydrophilicity.

[0082] In some embodiments, the main element of the catalytic layer 13 is Ni-Fe-Ox, and the ratio of Fe atoms to the total Ni-Fe atoms is 20%-40%. The doping elements of the catalytic layer 13 include at least one of Co, Mn, and Cr, and the ratio of the atoms of the doping elements to the total atoms is 15%-30%.

[0083] In this embodiment, by limiting the ratio of Fe atoms in the catalytic layer 13, the overpotential of the oxygen evolution electrode 1 is reduced, the catalytic performance is improved, and the reaction rate and efficiency are improved, so that the actual voltage required to achieve the relative current density is lower, the energy consumption is relatively smaller, and the catalytic activity is higher.

[0084] Based on the above content, the possible preparation method of the oxygen evolution electrode 1 is described in detail below in this embodiment.

[0085] In one embodiment (embodiment 1), a stainless steel mesh with uniform thickness is selected as the mesh substrate 11, and the stainless steel mesh is ultrasonically cleaned in ethanol and water to remove grease and surface debris.

[0086] Fix the stainless steel mesh on the rack and move it into the vacuum chamber. When the vacuum is drawn to 5 10 ﹣3 pa, turn on the heater to heat to 300°C, keep warm for a while, and then introduce Ar and O into the vacuum chamber. 2 At the same time, the titanium target and the nickel-iron alloy target were placed in a vacuum chamber, and the sputtering pressure was controlled at 2 Pa. At a deposition temperature of 300° C., the deposition current was controlled to be 5 A, the deposition time was 10 min, and the deposition bias was 1500 V, and a metal titanium bottom layer 12 was deposited.

[0087] Continue to deposit the catalytic layer 13 on the bottom layer 12, at a deposition temperature of 300°C, control the deposition current of the titanium target and the nickel-iron alloy target to be 5A, the deposition time to be 10min, and the deposition bias to be 1200V. Then, at a deposition temperature of 300°C, control the deposition current of the titanium target and the nickel-iron alloy target to be 10A, the deposition time to be 30min, and the deposition bias to be 500V. Finally, at a deposition temperature of 300°C, control the deposition current of the titanium target and the nickel-iron alloy target to be 10A, the deposition time to be 30min, and the deposition bias to be 500V. After the deposition is completed, gradually cool the vacuum chamber to room temperature to obtain an oxygen evolution electrode 1Ni-Fe-Ox electrode, and the thickness of the Ni-Fe-Ox electrode is 300nm.

[0088] After the oxygen evolution electrode 1 is moved to the reaction chamber, the reaction chamber is evacuated to 5 10 ﹣3 pa, and heat the reaction chamber to 600°C and keep it warm for a while. Then, the reaction gas H 2 , control the vacuum to maintain at 0.2 Pa, control the deposition bias to 800 V-1200 V, and the deposition temperature to 600 ° C. The processing time is 60 min.

[0089] In another embodiment (Example 2), a nickel mesh with uniform thickness is selected as the mesh substrate 11, and the nickel mesh is placed in ethanol and water for ultrasonic cleaning to remove surface grease and surface debris.

[0090] Fix the nickel mesh on the electrode holder, move it to the vacuum chamber and evacuate the inside of the chamber. When the vacuum reaches 5 When the pressure reaches 10-3Pa, turn on the heater to heat to 300℃ and keep it warm for a while. Then, introduce Ar and O into the vacuum chamber. 2 At the same time, titanium target, nickel target and iron target were placed in a vacuum chamber, and the sputtering pressure was controlled at 2 Pa. At a deposition temperature of 300° C., the deposition current was controlled to be 5 A, the deposition time was 10 min, and the deposition bias was 1500 V, and a metal titanium bottom layer 12 was deposited.

[0091] Continue to deposit the catalytic layer 13 on the bottom layer 12, at a deposition temperature of 300°C, control the deposition current nickel target 5A, iron target 3A, deposition time 15min, and deposition bias 1200V. At a deposition temperature of 300°C, control the deposition current nickel target 10A, iron target 3A, deposition time 30min, and deposition bias 500V. At a deposition temperature of 300°C, control the deposition current nickel target 12A, iron target 3A, deposition time 45min, and deposition bias 120V. After the deposition is completed, gradually cool the vacuum chamber to room temperature to obtain an oxygen evolution electrode 1 oxygen Ni-Fe-Ox electrode, and the Ni-Fe-Ox electrode is 500nm.

[0092] After the oxygen evolution electrode 1 is moved to the reaction chamber, the reaction chamber is evacuated to 5 10 ﹣3 pa, and heat the reaction chamber to 600°C and keep it warm for a while. Then, the reaction gas H 2 , control the vacuum to maintain at 0.2 Pa, control the deposition bias to 800 V-1200 V, and the deposition temperature to 600 ° C. The processing time is 60 min.

[0093] In another embodiment (Embodiment 3), a nickel mesh with uniform thickness is selected as the mesh substrate 11, and the nickel mesh is placed in ethanol and water for ultrasonic cleaning to remove surface grease and surface debris.

[0094] Fix the nickel mesh on the electrode holder, move it to the vacuum chamber and evacuate the inside of the chamber. When the vacuum reaches 5 When the pressure reaches 10-3Pa, turn on the heater to heat to 300℃ and keep it warm for a while. Then, introduce Ar and O into the vacuum chamber. 2 At the same time, a nickel target and a stainless steel 316L target were placed in a vacuum chamber, and the sputtering pressure was controlled at 2 Pa. At a deposition temperature of 300° C., a deposition current of 5 A, a deposition time of 10 min, and a deposition bias of 1500 V, a titanium bottom layer 12 was deposited.

[0095] Continue to deposit the catalytic layer 13 on the bottom layer 12, at a deposition temperature of 300°C, control the deposition current nickel target 5A, stainless steel target 2A, deposition time 10min, and deposition bias 1500V. At a deposition temperature of 300°C, control the deposition current nickel target 10A, stainless steel target 3A, deposition time 30min, and deposition bias 500V. At a deposition temperature of 300°C, control the deposition current nickel target 12A, stainless steel target 4A, deposition time 40min, and deposition bias 120V. After the deposition is completed, gradually cool the vacuum chamber to room temperature to obtain an oxygen evolution electrode 1 oxygen Ni-Fe-Cr-Ox electrode, and the thickness of the Ni-Fe-Cr-Ox electrode is 500nm.

[0096] The reaction chamber can be a vacuum environment. After the oxygen evolution electrode 1 is moved to the reaction chamber, the reaction chamber is evacuated to 5 10 ﹣3 The reaction chamber was heated to 800°C and kept warm for a period of time. Then, argon gas was introduced into the reaction chamber, the vacuum was controlled to be maintained at 0.01 Pa, the deposition bias was controlled to be 1000 V, and the deposition temperature was 800°C for 30 min.

[0097] In another embodiment (embodiment 4), a nickel mesh with uniform thickness is selected as the mesh substrate 11, and the nickel mesh is placed in ethanol and water for ultrasonic cleaning to remove surface grease and surface debris.

[0098] Fix the nickel mesh on the electrode holder, move it to the vacuum chamber and evacuate the inside of the chamber. When the vacuum reaches 5* When the pressure reaches 10-3Pa, turn on the heater to heat to 300℃ and keep it warm for a while. Then, introduce Ar and O into the vacuum chamber. 2 At the same time, a nickel target and an iron-cobalt alloy target were placed in a vacuum chamber, and the sputtering pressure was controlled at 2 Pa. At a deposition temperature of 300° C., a deposition current of 5 A, a deposition time of 10 min, and a deposition bias of 1500 V, a titanium bottom layer 12 was deposited.

[0099] Continue to deposit the catalytic layer 13 on the bottom layer 12, at a deposition temperature of 300°C, control the deposition current nickel target 5A, iron-cobalt alloy target 2A, deposition time 10min, and deposition bias 1500V. At a deposition temperature of 300°C, control the deposition current nickel target 10A, iron-cobalt alloy target 3A, deposition time 30min, and deposition bias 500V. At a deposition temperature of 300°C, control the deposition current nickel target 12A, iron-cobalt alloy target 4A, deposition time 40min, and deposition bias 120V. After the deposition is completed, gradually cool the vacuum chamber to room temperature to obtain an oxygen evolution electrode 1 oxygen Ni-Fe-Co-Ox electrode.

[0100] The oxygen evolution electrode 1 is moved to a reaction chamber, in which 0.1 M potassium hydroxide is arranged. After the oxygen evolution electrode 1 is moved to the reaction chamber, the potassium hydroxide is heated to 120° C. for 30 min. After completion, the electrode is taken out and dried.

[0101] This embodiment also provides an oxygen evolution electrode 1, which is prepared by the above method, and this embodiment will not be repeated here. Figure 2 The oxygen evolution electrode 1 includes a mesh substrate 11, a bottom layer 12 and a catalyst layer 13 in an integrated structure. The mesh substrate 11 is a diffusion layer. That is, in this embodiment, the bottom layer and the catalyst layer of the oxygen evolution electrode 1 are deposited on the surface of the diffusion layer by a vacuum deposition process, so that the diffusion layer and the catalyst layer 13 are in an integrated structure.

[0102] This embodiment also provides an electrolytic cell, which includes an oxygen evolution electrode 1, an exchange membrane and a hydrogen evolution electrode arranged in a stacked manner. The hydrogen evolution electrode can be prepared by the above-mentioned contents, which will not be described in detail in this embodiment. The electrolytic cell can be used to electrolyze the electrolyte in the electrolytic cell to produce hydrogen and oxygen.

[0103] In some embodiments, the electrolyte in the electrolytic cell may be an alkaline solution or pure water. Water molecules in the electrolyte undergo oxygen evolution reaction and hydrogen evolution reaction on the oxygen evolution electrode 1 and the hydrogen evolution electrode, respectively, thereby being decomposed into hydrogen and oxygen.

[0104] Since the catalytic layer 13 on the oxygen evolution electrode 1 in this embodiment is deposited on the surface of the diffusion layer by vacuum deposition, the catalytic layer 13 can be stably attached to the diffusion layer during the oxygen evolution reaction and is not easy to fall off, thereby improving the stability of the electrolytic cell.

[0105] Please refer to Figure 5 , Figure 5 This is a comparison diagram of polarity curves of Example 1 and Example 4 and the comparative example (untreated porous diffusion layer) in the present application, showing the relationship between current density and voltage in the electrolytic cell. At the same current density, the lower the voltage, the smaller the external output power, and the better the oxygen evolution performance of the oxygen evolution electrode 1.

[0106] from Figure 5 It can be seen that under the same current density, the voltage of the oxygen evolution electrode 1 prepared in Example 1 and Example 4 is significantly lower than the voltage of the oxygen evolution electrode 1 prepared in the comparative example. Therefore, the oxygen evolution electrode 1 prepared in this example has a relatively excellent oxygen evolution performance.

[0107] Figure 6 Schematic diagram showing the change of the voltage required for electrolysis of water in the electrolytic cell over time in this embodiment. Figure 6It can be seen that the voltage required for the electrolytic cell assembled with the oxygen evolution electrode 1 prepared in this embodiment to electrolyze water does not fluctuate significantly, and the voltage is stable, indicating that the electrolytic cell has stable electrolysis performance, good alkali resistance and durability, and can maintain long-term stable operation. This shows that the oxygen evolution electrode 1 prepared in this embodiment has excellent stability.

[0108] Therefore, the preparation method of the present application can be used to prepare an oxygen evolution electrode 1 with high activity and high stability, and the preparation process is simple. Compared with the preparation of electrodes by chemical plating and electroplating processes, the risk of sewage pollution to the environment is reduced.

[0109] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preparing an oxygen evolution electrode, characterized in that: The preparation method comprises: Placing a mesh substrate (11) and a target material into a vacuum chamber, introducing a protective gas and a reaction gas into the vacuum chamber, applying a deposition current and a deposition bias voltage, and using the target material to deposit on the mesh substrate (11) to form a bottom layer (12); Gradually increasing the deposition current and gradually decreasing the deposition bias voltage, using the target material to deposit on the bottom layer (12) to form a catalytic layer (13), thereby obtaining the oxygen evolution electrode (1); The oxygen evolution electrode (1) is moved into a reaction chamber, and a reaction medium is introduced into the reaction chamber to etch the catalyst layer, so that the catalyst layer (13) has a porous network; When the deposition current is gradually increased and the deposition bias voltage is gradually decreased, the target material is used to deposit a catalytic layer (13) on the bottom layer (12) to obtain the oxygen evolution electrode (1), the deposition current is gradually increased from 5A to 12A, and the deposition voltage is gradually decreased from 1500V to 120V; The main element of the catalyst layer (13) is Ni-Fe-Ox, and the ratio of Fe atoms to the total Ni-Fe atoms is 20%-40%; The doping element of the catalytic layer (13) includes at least one of Co, Mn and Cr, and the proportion of atoms of the doping element to total atoms is 15%-30%.

2. The method for preparing an oxygen evolution electrode according to claim 1, characterized in that: The material of the mesh substrate (11) includes at least one of a titanium mesh, a stainless steel mesh, and a nickel mesh.

3. The method for preparing an oxygen evolution electrode according to claim 1, characterized in that: The protective gas and reaction gas are O2 and Ar.

4. The method for preparing an oxygen evolution electrode according to claim 1, characterized in that: When a target material is deposited on the mesh substrate (11) to form a bottom layer (12), the method specifically comprises: using a physical vapor deposition process or an electroplating impact process to deposit the target material on the surface of the mesh substrate (11) to form the bottom layer (12).

5. The method for preparing an oxygen evolution electrode according to claim 1, characterized in that: The target material includes at least one of a titanium target material, a nickel target material, an iron target material, a nickel-iron alloy target material, a stainless steel target material, and an iron-cobalt alloy target material.

6. The method for preparing an oxygen evolution electrode according to claim 1, characterized in that: The material of the bottom layer (12) includes one or more combinations of metals of nickel, titanium, aluminum and alloy oxide materials thereof.

7. The method for preparing an oxygen evolution electrode according to claim 1, characterized in that: The reaction medium is H2 or Ar or an alkaline solution.

8. The method for preparing an oxygen evolution electrode according to claim 1, characterized in that: The thickness of the oxygen evolution electrode (1) is 300nm-500nm.

9. The method for preparing an oxygen evolution electrode according to claim 1, characterized in that: The specific surface area of ​​the oxygen evolution electrode (1) is greater than 100 m 2 / g.

10. The method for preparing an oxygen evolution electrode according to claim 1, characterized in that: The surface contact angle of the oxygen evolution electrode (1) is less than 40°.

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