An electrolyzer, an anode catalyst, its preparation method and application

Abstract

This application provides an electrolytic cell, an anode catalyst material, a preparation method thereof, and an application thereof. The anode catalyst material in this application includes: a substrate, which is an alloy containing nickel and iron; and a nickel-rich oxide layer, which is coated on the surface of the substrate. The nickel-rich oxide layer contains nickel oxide and / or nickel hydroxide, and the mass content of nickel in the metal component of the nickel-rich oxide layer is greater than 70%.

Description

Technical Field

[0001] This application relates to the field of oxygen production by electrolysis, and more particularly to the field of oxygen production by water electrolysis. Specifically, this application relates to an electrolyzer, an anode catalyst, a method for preparing the same, and its application. Background Technology

[0002] In alkaline water electrolysis for oxygen production, a high-concentration alkaline solution is typically used as the electrolyte in the electrolyzer, operating at a temperature of 75-90℃. In this environment, the kinetics of the oxygen evolution reaction on the anode side are sluggish, which is a bottleneck restricting oxygen production through alkaline water electrolysis. Furthermore, the anode-side chamber of the electrolyzer needs to withstand high voltage (1.6~3 V) while continuously resisting the release of oxygen. Therefore, the anode electrode material must possess good electrochemical activity and resistance to alkali and oxygen corrosion.

[0003] In the process of realizing the concept of this application, the inventors discovered at least the following problems in the related technology: the related technology uses metallic nickel, which has good resistance to alkali corrosion, as the anode material, but the oxygen evolution performance of pure nickel material is limited, which leads to a high overpotential at the anode of the electrolytic cell and affects the overall electrolysis efficiency. Summary of the Invention

[0004] In view of the above, in order to at least partially solve at least one of the aforementioned technical problems, this application provides an anode catalytic material, a method for its preparation, and its application.

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

[0006] According to one embodiment of this application, an anode catalyst material is provided, comprising: a substrate, which is an alloy containing nickel and iron; and a nickel-rich oxide layer, which is coated on the surface of the substrate, wherein the nickel-rich oxide layer contains nickel oxide and / or nickel hydroxide, and the mass content of nickel in the metal component of the nickel-rich oxide layer is greater than 70%.

[0007] According to another embodiment of this application, a method for preparing the above-mentioned anode catalyst material is provided, comprising: depositing a nickel-containing metal layer on the surface of a substrate to obtain an intermediate, wherein the substrate is an alloy containing nickel and iron; using the intermediate as an anode, performing anodic oxidation in an alkaline electrolyte to form a nickel-rich oxide layer, thereby obtaining the anode catalyst material.

[0008] According to another embodiment of this application, a method for preparing an anode catalyst material is provided, comprising: providing a substrate, wherein the mass ratio of nickel to iron in the substrate is 0.4 to 10, and the mass content of nickel is 21% to 80%; and using the substrate as an anode, performing anodic oxidation in an alkaline electrolyte to obtain the anode catalyst material.

[0009] According to another embodiment of this application, an application of the above-mentioned anode catalyst material as an anode in the field of electrolytic oxygen production is provided.

[0010] According to another embodiment of this application, an application of stainless steel or nickel-based alloy in the preparation of anode catalyst materials is provided, wherein the mass ratio of nickel to iron in the stainless steel or nickel-based alloy is 0.4 to 10, and the mass content of nickel is 21% to 80%.

[0011] According to another aspect of this application, an electrolyzer is provided, the electrolyzer comprising the anode catalyst material described in any of the preceding claims.

[0012] According to the anodic catalytic material, its preparation method, and its application provided in the embodiments of this application, firstly, an alloy containing nickel and iron is used as the substrate of the anodic catalytic material. A nickel-rich oxide layer can be coated on the substrate surface by anodizing, thereby reducing the anodic overpotential and thus reducing the energy consumption of water electrolysis. Secondly, by controlling the ratio of nickel to iron in the alloy, the long-term stability of the nickel-rich oxide layer can be improved. While maintaining a low overpotential, the dissolution of other elements (such as iron) in the substrate is significantly suppressed, enhancing the stability of the catalytic material and improving the purity of the produced oxygen. Especially for high nickel-iron ratio alloys, they can be directly anodized to obtain the anodic catalytic material, which is suitable for preparing anodic catalytic materials by in-situ anodizing. For low nickel-iron ratio alloys, a nickel-containing metal layer can be deposited on its surface. After increasing the nickel content on the substrate surface, anodizing can also be used to construct a long-term structurally stable nickel-rich oxide layer on the substrate surface. In addition, when the alloy material contains an appropriate amount of molybdenum, trace amounts of molybdenum will dynamically deposit on the cathode side, improving the surface structure and electrocatalytic activity of the cathode, thereby enhancing the catalytic performance of the cathode and reducing the overall electrolysis energy consumption. The electrolyzer of this application has the same or similar advantages as the prior art and the aforementioned anode catalyst materials, which will not be elaborated here. Attached Figure Description

[0013] The above and other objects, features and advantages of this application will become clearer from the following description of embodiments with reference to the accompanying drawings, in which:

[0014] Figure 1 This is a schematic diagram of the preparation method of the anode catalyst material according to an embodiment of this application;

[0015] Figure 2 This is a cross-sectional scanning electron microscope (SEM) image of the 904L anode obtained in Example 1 of this application;

[0016] Figure 3This is a graph showing the voltage change in the electrolytic cell chamber of the 904L anode obtained in Example 1 of this application after working for 20 days.

[0017] Figure 4 This is a graph showing the change in hydrogen content in oxygen of the 904L anode obtained in Example 1 of this application after working in the electrolytic cell chamber for 15 days;

[0018] Figure 5 This is a cross-sectional scanning electron microscope image of the 904L anode obtained in Example 1 of this application after working in the electrolytic cell chamber for 20 days;

[0019] Figure 6 The image shows a scanning electron microscope (SEM) image of the cathode material surface after 20 days of operation of the electrolytic cell containing the 904L anode obtained in Example 1 of this application.

[0020] Figure 7 The images show the cathode polarization curves of the electrolytic cell chamber in Example 1 of this application before and after 20 days of continuous operation.

[0021] Figure 8 The voltage change curve of the pure nickel mesh anode of Comparative Example 1 of this application after working in the electrolytic cell for 10 days is shown.

[0022] Figure 9 The voltage change curve of the 304 stainless steel in Comparative Example 2 of this application after working in the electrolytic cell for 20 days is shown.

[0023] Figure 10 The graph shows the change in hydrogen content in oxygen of the 304 stainless steel used in Comparative Example 2 of this application after working in the electrolytic cell chamber for 20 days.

[0024] Figure 11 This is a scanning electron microscope image of the anode and cathode material surfaces after 20 days of operation in the electrolytic cell chamber of Comparative Example 2 of this application.

[0025] Figure 12 The image shows the EDS energy spectrum of the anode surface of the 304 stainless steel in Comparative Example 2 of this application after working in the electrolytic cell chamber for 20 days. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0027] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of this application. The terms “comprising,” “including,” etc., as used herein indicate the presence of features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components. All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein should be interpreted in a manner consistent with the context of this specification and should not be interpreted in an idealized or overly rigid manner.

[0028] In the field of oxygen electrolysis, nickel has become the mainstream choice for anode catalysts due to its excellent resistance to alkali corrosion. However, the high price of pure nickel and its relatively limited oxygen evolution performance directly affect the overall electrolysis efficiency and economics. Therefore, how to improve electrolysis efficiency while ensuring high system reliability and effectively reducing material costs through optimized design of the anode and corresponding electrolytic cell system has become an urgent problem to be solved in the development of alkaline water electrolysis technology.

[0029] In realizing the concept of this application, it was discovered that cheaper nickel- and iron-containing alloys, such as stainless steel, can be used as anode catalysts for alkaline water electrolysis, thereby reducing the oxygen evolution overpotential and improving oxygen evolution efficiency. However, further investigation revealed that with increasing usage time, metal deposits in the cathode chamber of the electrolyzer gradually increase, affecting the electrolyzer performance and even potentially causing diaphragm puncture. Experimental analysis suggests that this is because the iron in the alloy is oxidized during electrolysis, forming the intermediate product HFeO2. - Furthermore, it readily reacts with alkaline solutions, transforming into Fe₂O₃ or FeOOH, which then detach from the electrode surface and enter the electrolyte. Moreover, Fe ions in the electrolyte easily deposit on the cathode surface during electrolysis, even growing into dendritic structures. These dendritic structures may grow and penetrate the membrane to reach the anode side, causing hydrogen evolution reactions to occur there as well, severely affecting the hydrogen content in the oxygen content and posing a significant safety hazard.

[0030] Furthermore, it was discovered that common alloying elements such as chromium (Cr), manganese (Mn), molybdenum (Mo), and silicon (Si) also migrate into the electrolyte in ionic form. Chromium readily migrates into the electrolyte in its high-valence oxygen ion form (CrO4). 2- or Cr2O7 2- Manganese exists in the electrolyte; initially, it exists as MnO4. 2- It dissolves in form and will later be deposited on the cathode as MnO2; molybdenum will also partially dissolve as MoO4. 2- Form leaching. The continued leaching of these elements can affect the stability of the substrate framework structure and the purity of the produced oxygen.

[0031] Therefore, this invention coats a dense nickel-rich oxide layer onto a nickel- and iron-containing alloy substrate, the nickel-rich oxide layer comprising nickel oxide and / or nickel hydroxide. First, this nickel-rich oxide layer forms a protective barrier, effectively isolating the substrate from the electrolyte and inhibiting further metal ion deposition during electrolysis. This avoids the risk of the alloy substrate's framework structure collapsing due to continuous corrosion, ensuring the original mechanical stability of the alloy substrate. Second, the nickel oxide and / or nickel hydroxide in the nickel-rich oxide layer, and may further contain a certain amount of nickel-iron hydroxide, possess highly efficient catalytic activity, providing abundant active sites for the electrolysis reaction, further promoting the oxidative decomposition of water molecules on the anode side, and improving water decomposition efficiency.

[0032] Specifically, according to one aspect of the present application, an anode catalyst material is provided, comprising a substrate and a nickel-rich oxide layer, wherein: the substrate is an alloy containing nickel and iron; the nickel-rich oxide layer covers the surface of the substrate, wherein the nickel-rich oxide layer contains nickel oxide and / or nickel hydroxide, and the mass content of nickel in the metal component of the nickel-rich oxide layer is greater than 70%.

[0033] According to embodiments of this application, an "alloy" is a material with metallic properties obtained by alloying one metal with one or more other metals or non-metals through processes such as smelting. In other words, in addition to metallic elements, it may also include non-metallic elements (C, Si, N, etc.).

[0034] According to the embodiments of this application, "nickel oxide and / or nickel hydroxide" mainly refers to nickel oxide or hydroxy oxide. As can be seen from the anodic reaction of metallic nickel, the valence state of nickel can include +2, +3, etc., specifically including one or more of NiO, Ni2O3, NiOOH, Ni(OH)2, etc.

[0035] According to embodiments of this application, firstly, the anode catalyst material uses an alloy of nickel and iron as the substrate. The addition of iron promotes proton conduction and charge transport, effectively reducing the oxygen evolution overpotential of the substrate material. Secondly, a nickel-rich oxide layer is coated on the substrate surface. The nickel-rich oxide layer can passivate the substrate, inhibit the precipitation of metal ions in the substrate, prevent the collapse of the alloy substrate framework structure, and maintain the original mechanical stability of the alloy substrate. Thirdly, when used as an anode, the thickness of the nickel-rich oxide layer does not significantly increase after it stabilizes, thus not affecting its catalytic performance. In addition, the nickel oxide and / or nickel hydroxide contained in the nickel-rich oxide layer, and may further contain nickel-iron hydroxide, also serve as active components in the catalytic reaction. Through close bonding with the substrate material, they ensure that the substrate material can efficiently transfer electrons to the catalyst, further guaranteeing the catalytic activity of the material.

[0036] According to embodiments of this application, the mass ratio of nickel to iron in the substrate is 0.15 to 10, for example, the mass ratio of nickel to iron can be 0.15, 0.16, 0.45, 0.5, 1, 1.1, 1.35, 3, 4.2, 5, 7, 9, or 10. The mass content of nickel is not less than 10%, for example, it can be 10%, 11%, 20%, 25%, 34%, 40%, 43%, 50%, 60%, 70%, 75%, 76%, 80%, 85%, or 90%. When the nickel content in the substrate is less than 10%, it is difficult to form a structurally stable nickel-rich oxide layer on the substrate surface by anodizing. At the same time, the nickel content in the substrate should not be too high, as excessive nickel content will lead to a high anodic overpotential, thereby reducing oxygen evolution performance and affecting the overall electrolysis efficiency. Preferably, the mass content of nickel in the substrate is 10% to 80%.

[0037] According to the embodiments of this application, since a nickel-rich oxide layer is formed, materials with a wide range of nickel-iron mass ratios and varying nickel content can be selected as the substrate. On the one hand, this can achieve lower energy consumption for water electrolysis by having a lower anodic overpotential. On the other hand, it can also maintain structural stability to flexibly adapt to the needs of different applications.

[0038] According to embodiments of this application, the mass ratio of nickel to iron in the substrate is 0.15 or more and less than 0.4, for example, the mass ratio of nickel to iron can be 0.15, 0.16, 0.17, 0.18, 0.2, 0.25, 0.3, 0.35, or 0.39. The mass content of nickel is 10% to 21%, for example, 10%, 11%, 13%, 14%, 16%, 18%, or 21%. In this case, the preferred anode catalyst material also includes elemental nickel or a nickel-based alloy, present between the substrate and the nickel-rich oxide layer.

[0039] According to embodiments of this application, there is elemental nickel or a nickel-based alloy between the low-nickel content substrate and the nickel-rich oxide layer, which effectively supports and promotes the stable formation of the nickel-rich oxide layer, ensuring good bonding and performance between the oxide layer and the substrate.

[0040] According to embodiments of this application, the mass ratio of nickel to iron in the substrate is 0.4 to 10, for example, the mass ratio of nickel to iron can be 0.4, 0.45, 0.8, 1.1, 1.35, 2, 4, 4.2, 5, 6, 8, 9, or 10, and the mass content of nickel is 21% to 80%, for example, 21%, 25%, 30%, 34%, 43%, 60%, 70%, 75%, 76%, or 80%.

[0041] According to embodiments of this application, there is no need for elemental nickel to exist between the high-nickel-content substrate and the nickel-rich oxide layer.

[0042] According to embodiments of this application, the total mass content of elements other than nickel and iron in the substrate is less than or equal to 30%, and the other elements include Cr, Mn, Mo, Si, etc., and the total mass content can be, for example, 30%, 25%, 20%, 10%, 5%; the other elements preferably include molybdenum, and the mass content of molybdenum is less than 5%, for example, 4%, 3%, 2%, 1%, 0.5%.

[0043] According to embodiments of this application, since other elements (Cr, Mn, Mo, Si, etc.) in the substrate have low oxygen evolution activity, excessively high content is detrimental to improving the efficiency of the oxygen evolution reaction. However, the presence of an appropriate amount of molybdenum is preferred. During water electrolysis, as the anodic reaction proceeds, trace amounts of molybdenum will be released as MoO4. 2- The morphology dissolves from the anode surface and dynamically deposits on the cathode side in a specific chemical form, which can improve the surface structure and electrocatalytic activity of the cathode, enhance the catalytic performance of the cathode, and thus reduce the overall electrolysis energy consumption.

[0044] According to embodiments of this application, the substrate may include nickel-containing stainless steel or a nickel-based alloy, wherein the stainless steel is selected from 316 stainless steel, 305J1 stainless steel, 309s stainless steel, 310s stainless steel, 314 stainless steel, 316L stainless steel, 321 stainless steel, and 904L stainless steel, and the nickel-based alloy is selected from 800 nickel-based alloy, 825 nickel-based alloy, 601 nickel-based alloy, or 600 nickel-based alloy.

[0045] According to embodiments of this application, the substrate may further include a custom-made synthetic material that meets the nickel content requirements, and a material corresponding to a metal material with a low nickel content that has had its surface nickel content increased through methods such as surface nickel enrichment, electrodeposition, or chemical coating. Further optionally, the substrate may be a commercially available stainless steel or nickel-based alloy material with a nickel-containing metal layer (e.g., elemental nickel or nickel-iron alloy) plated on its surface. For example, a nickel-iron alloy may be plated on the surface of 316L stainless steel. The nickel-iron alloy may have a nickel-to-iron mass ratio of 0.4 to 10, such as 0.4, 0.8, 2, 4, 5, 6, 8, or 10, and a nickel content of 21% to 80%, such as 21%, 25%, 30%, 34%, 43%, 60%, 70%, 75%, 76%, or 80%.

[0046] According to the embodiments of this application, the shape of the substrate material is not limited, such as metal wire mesh, metal plate, plate mesh, etc., and stainless steel or nickel-based alloy can be used. The materials are inexpensive and readily available, which effectively reduces the overall cost of the catalytic material and improves its economy and practicality.

[0047] According to embodiments of this application, the mass ratio of nickel to iron in the nickel-rich oxide layer is greater than 2.5, for example, the mass ratio of nickel to iron can be 2.6, 2.7, 2.8, 2.9, 3, 3.5, 4, 6, 8, or 10; and / or the thickness of the nickel-rich oxide layer is 0.5 to 5 μm, for example, 0.5 μm, 1 μm, 2 μm, 3 μm, 4 μm, or 5 μm, preferably 0.5 to 1.5 μm.

[0048] According to embodiments of this application, a higher nickel content in the nickel-rich oxide layer is beneficial for the formation of a dense oxide layer, thereby reducing the ion dissolution effect in the substrate material and improving the overall stability of the anode catalyst material. The thickness of the nickel-rich oxide layer can also be adjusted within a wide range to flexibly adapt to the needs of different applications. However, if the nickel content in the nickel-rich oxide layer is too high or the thickness of the nickel-rich oxide layer is too thick, it will be detrimental to the reduction of overpotential and will reduce electronic conductivity. If the nickel content is too low, it will be difficult to form a dense porous structure, which will be detrimental to suppressing the dissolution of metal ions.

[0049] According to another embodiment of this application, a method for preparing the above-described anode catalyst material is provided. Figure 1 This is a schematic diagram of the preparation method of the anode catalyst material according to an embodiment of this application, as shown below. Figure 1 As shown, the preparation method of this application may include the following steps S101 to S102.

[0050] In step S101, a nickel-containing metal layer is deposited on the surface of the substrate to obtain an intermediate, wherein the substrate is an alloy containing nickel and iron.

[0051] In step S102, using the intermediate as the anode, anodic oxidation is performed in an alkaline electrolyte to form a nickel-rich oxide layer, thereby obtaining the anode catalyst material.

[0052] According to embodiments of this application, a nickel-containing metal layer is deposited on a substrate to increase the nickel content on the substrate surface, and then anodizing is performed to construct a nickel-rich oxide layer on the substrate surface. The nickel-rich oxide layer can inhibit the dissolution of metal ions from the substrate, and the resulting anodic catalyst exhibits good oxygen evolution performance when used as an anode. Furthermore, once the nickel-rich oxide layer has stabilized, its thickness does not significantly increase when used as an anode, thus not affecting its catalytic performance.

[0053] According to an embodiment of this application, in step S101, depositing a nickel-containing metal layer on the surface of the substrate may specifically include: using the substrate as a cathode and performing electrodeposition in an electrolyte containing a nickel source.

[0054] According to an embodiment of this application, in step S101, the nickel-containing metal layer can be, for example, elemental nickel or a nickel-based alloy material. More specifically, it can be a nickel-iron alloy plated onto the surface of stainless steel or a nickel-based alloy. The nickel-iron alloy can have a nickel-to-iron element mass ratio of 0.4 to 10, for example, 0.4, 0.45, 0.8, 1.1, 1.35, 2, 4, 4.2, 5, 6, 8, 9, or 10.

[0055] According to embodiments of this application, a nickel-containing metal layer is formed on the substrate surface using electrodeposition technology. The operation process is simple, and the amount of nickel-containing metal layer deposited can be controlled by controlling various deposition conditions. It should be noted that this electrodeposition step does not require the formation of a dense nickel layer on the electrode surface, but only requires increasing the nickel content located on the substrate surface.

[0056] According to embodiments of this application, optionally, the nickel source in the electrolyte can be one or more of nickel nitrate, nickel sulfate, and nickel sulfide. Furthermore, the electrolyte may also contain other additives, such as boric acid, sodium chloride, sodium nitrate, sodium citrate, sodium acetate, sodium saccharin, etc.

[0057] According to embodiments of this application, optionally, the amount of nickel-containing metal layer deposited on the substrate surface can be controlled by the total amount of electrodeposition, depending on the nickel content of the substrate. Specifically, assuming that all non-nickel portions of the substrate material are replaced by nickel, the number of nickel moles that can be deposited on the electrode surface x = (1 - bulk nickel mole content) × electrode contact area (cm²) 2 ) / Nickel atomic area (6.5 × 10 -14 cm 2 ) / molar atomic weight (6.02 × 10 23 );

[0058] Assuming the substrate material is entirely replaced by nickel, the number of moles of nickel that can be deposited on the electrode surface, y = 1 × the electrode contact area (cm²). 2 ) / Nickel atomic area (6.5×10 -14 cm 2 ) / molar atomic weight (6.02 × 10 23 Based on the above assumptions, the amount of nickel deposited, D (mol), should be less than or equal to 20y (the number of atomic layers of nickel is less than 20), preferably greater than or equal to 5x and less than or equal to 15y; the corresponding total charge, Q, is 2D × 96500 coulombs. The amount of metallic nickel deposited can be controlled by using a small or large current in combination with an appropriate time (Q = I × t).

[0059] According to an embodiment of this application, before step S101, the preparation method of this application may further include a pretreatment step of the substrate, that is, the substrate may be subjected to surface pickling treatment: specifically, the substrate may be immersed in a 0.5~6M hydrochloric acid, nitric acid or sulfuric acid solution for 15min~24h, rinsed with pure water, and dried in an environment of room temperature to 50°C.

[0060] According to an embodiment of this application, in step S102, the conditions for anodizing include: using a 10% to 50% (e.g., 10%, 20%, 25%, 30%, 35%, 40%, 50%) NaOH or KOH electrolyte, at a temperature of 25 to 95°C (e.g., 25°C, 40°C, 50°C, 60°C, 70°C, 80°C, 95°C), applying a voltage of 1.5 to 3.5 V (e.g., 1.5 V, 1.8 V, 2.0 V, 2.2 V, 2.5 V, 3.0 V, 3.5 V), for a duration of 72 to 1440 hours (e.g., 72 hours, 90 hours, 120 hours, 240 hours, 360 hours, 480 hours, 600 hours, 840 hours, 1080 hours, 1320 hours, 1440 hours).

[0061] According to an embodiment of this application, preferably, the mass ratio of nickel to iron in the substrate is 0.4 to 10, and the mass content of nickel is 21% to 80%. In this case, the preparation method of this application is to use the substrate as an anode and perform anodic oxidation in an alkaline electrolyte to obtain the anode catalyst material.

[0062] According to embodiments of this application, for the substrate having a preferred nickel and iron composition, the anodizing in step S102 can be achieved by directly using the substrate as an anode material in an industrial alkaline bath, where a nickel-rich oxide layer can be formed in situ on the substrate within a certain period of time (e.g., 15-60 days). The anodizing time can be determined based on the substrate material and application requirements, and as the nickel content in the substrate material increases, the anodizing time can be appropriately increased to form a more stable nickel-rich oxide layer.

[0063] According to another embodiment of this application, an application of the above-mentioned anode catalyst material as an anode in the field of electrolytic oxygen production is provided.

[0064] According to the embodiments of this application, the anode catalyst material of this application has a lower anode overpotential than pure nickel electrodes of the same specification. When applied to the process of electrolytic oxygen production, the chamber potential can be reduced by 120~210mV, thereby achieving lower energy consumption for water electrolysis oxygen production. The material cost is also reduced by 25~75% compared to pure nickel anode materials.

[0065] According to another embodiment of this application, an application of stainless steel or nickel-based alloy in the preparation of anodic catalyst materials is provided, wherein the mass ratio of nickel to iron in the stainless steel or nickel-based alloy is 0.4 to 10 (e.g., 0.4, 0.45, 0.8, 1.1, 1.35, 2, 4, 4.2, 5, 6, 8, 9, 10), and the mass content of nickel is 21% to 80% (e.g., 21%, 25%, 30%, 34%, 43%, 60%, 70%, 75%, 76%, 80%).

[0066] According to embodiments of this application, the aforementioned stainless steel or nickel-based alloy, when used in the preparation of anodic catalyst materials, can facilitate the formation of a stable nickel-rich oxide layer on the surface. On one hand, the nickel-rich oxide layer can passivate the substrate, inhibit the precipitation of metal ions in the substrate, prevent the collapse of the alloy substrate's framework structure, and maintain the original mechanical stability of the alloy substrate. On the other hand, the nickel oxides and / or nickel hydroxides contained in the nickel-rich oxide layer, and may further contain nickel-iron hydroxides, can serve as active components in the catalytic reaction. Through close bonding with the substrate material, they ensure that the substrate material can efficiently transfer electrons to the catalyst, while further guaranteeing the catalytic activity of the material.

[0067] According to embodiments of this application, the stainless steel or nickel-based alloy may be selected from 314 stainless steel, 904L stainless steel, 800 nickel-based alloy, 825 nickel-based alloy, 601 nickel-based alloy or 600 nickel-based alloy with a nickel-to-iron mass ratio ≥0.4 and a nickel content ≥21%.

[0068] According to embodiments of this application, the anode catalyst material prepared from the aforementioned stainless steel or nickel-based alloy can be used in the alkaline water electrolysis oxygen production reaction. This is beneficial for improving the reactivity and stability of water electrolysis oxygen production, and also helps to reduce the energy consumption of water electrolysis oxygen production, offering the advantage of low cost.

[0069] According to embodiments of this application, the method for preparing the anodic catalyst material is an in-situ anodic oxidation preparation method. Here, "in-situ" means that stainless steel or nickel-based alloys can first undergo an anodic oxidation reaction in the reaction system to generate the anodic catalyst material, which is then used as the anodic catalyst material in that system, without needing to first prepare the anodic catalyst material in one reaction system and then transfer it to another reaction system for use as the anodic catalyst. More preferably, the stainless steel or nickel-based alloy is anodized in an equipment for generating oxygen using an alkaline electrolyte, wherein the equipment for generating oxygen using an alkaline electrolyte can be 100-5000 Nm. 3 An industrial bipolar electrolyzer with a capacity of 1000 m³ / h, wherein the alkaline electrolyte is 30%-35% KOH, the system pressure during operation is 0.1MPa-3MPa, preferably 1-2MPa; the chamber voltage is 2V-2.8V, and the temperature is 75℃-90℃.

[0070] According to an embodiment of this application, an electrolytic cell is provided, the electrolytic cell including the anode catalyst material described in any of the above claims, the electrolytic cell can be a device for generating oxygen by electrolysis with an alkaline electrolyte, such as an alkaline water oxygen electrolytic cell (ALK).

[0071] The present invention will be further illustrated below through embodiments and related test experiments. In the following detailed description, numerous specific details are set forth to provide a comprehensive understanding of the embodiments of the present invention for ease of explanation. However, it will be apparent that one or more embodiments may be practiced without these specific details. Moreover, the details in the following embodiments can be arbitrarily combined to form other feasible embodiments without conflict.

[0072] Example 1:

[0073] In industrial alkaline electrolytic cell oxygen production applications, 904L stainless steel with a nickel-to-iron mass ratio of approximately 0.45, a nickel content of approximately 25%, and a molybdenum content of approximately 4% is selected as the base material. The structure is 5×5cm. 2 The size is plain weave, made with 250 μm wire diameter and 50 mesh.

[0074] The aforementioned 904L stainless steel mesh was placed in the electrolytic cell, and a 5×5 cm electrode was selected. 2 A pure nickel mesh of a specific size, woven with 250 μm wire diameter and 50 mesh, was used. A 30% KOH solution was selected as the electrolyte, and PPS fabric was used as the diaphragm. The mesh was continuously operated for 30 days under normal pressure, 85℃, and 2.3V conditions. Afterward, the mesh was removed, washed, and dried to obtain the 904L anode. During this process, a nickel-rich oxide layer gradually formed and stabilized on the surface of the 904L anode.

[0075] The 904L anode with a nickel-rich oxide layer, the new pure nickel mesh cathode, and the diaphragm were reassembled in the electrolytic cell chamber to carry out the water electrolysis oxygen production reaction. The operating temperature was 85℃, the operating pressure was atmospheric pressure, and the operating current density was 3000 A / m³. 2 .

[0076] Figure 2 This is a cross-sectional view of the 904L anode obtained in Example 1 of this application. Elemental analysis of the nickel-rich layer (gray box region) using an energy dispersive spectroscopy (EDS) instrument revealed a nickel-iron ratio of 2.9 and a Ni content of 71% among the metallic elements (Ni, Fe, Cr, Mn, Mo). Figure 2 The thickness of the nickel-rich layer shown is approximately 1 μm.

[0077] Figure 3This is a graph showing the voltage change in the electrolytic cell chamber of the 904L anode with a nickel-rich oxide layer obtained in Example 1 of this application after working for 20 days.

[0078] like Figure 3 As shown, during the 20-day continuous operation of the electrolytic cell chamber, the voltage change trend of the chamber showed good stability, basically maintained at around 2.14 V, without significant upward or downward trends, proving that the anode material used can ensure that the electrolytic cell can operate stably for more than 20 days under the above operating conditions.

[0079] Figure 4 This is a graph showing the change in hydrogen content in oxygen of the 904L anode obtained in Example 1 of this application after working in the electrolytic cell chamber for 15 days.

[0080] like Figure 4 As shown, the hydrogen content in the oxygen in the electrolytic cell remained at a low level for 15 consecutive days of operation, basically below 0.1%. Using this anode, the system can operate safely and stably for a long time.

[0081] Figure 5 This is a cross-sectional scanning electron microscope (SEM) image of the 904L anode obtained in Example 1 of this application after working in the electrolytic cell chamber for 20 days; from Figure 7 It can be seen that the nickel-rich oxide layer on the surface of the anode did not change significantly after 20 days of operation, and its thickness was still about 1 μm.

[0082] Figure 6 The image shows a scanning electron microscope (SEM) image of the cathode material surface after the electrolytic cell containing the 904L anode obtained in Example 1 of this application has been running for 20 days. (a) is a scanning electron microscope image of the cathode surface, and (b) is a magnified view of (a).

[0083] like Figure 6 As shown, after the electrolytic cell chamber ran continuously for 20 days, no significant changes were observed on the corresponding cathode surface, indicating that there was no significant dissolution and redeposition of metals. However, elemental analysis of the cathode surface by energy dispersive spectroscopy revealed that the cathode surface contained 0.24% by mass molybdenum, meaning that trace amounts of molybdenum dissolved from the anode surface were dynamically deposited on the cathode side.

[0084] In addition, polarization curves of the cathodes in the electrolytic cell chamber were tested before and after 20 days of continuous operation. The test conditions were as follows: room temperature, 1 mol / L KOH, three-electrode system, with the working electrode being the corresponding cathode, and an effective area of ​​1×1 cm². 2 The counter electrode is a pure nickel mesh, and the reference electrode mesh is an Hg / HgO electrode. For example... Figure 7As shown, under the same current density, the overpotential required by the cathode after 20 days of continuous operation of the electrolyzer chamber is reduced, indicating that the deposition of molybdenum can improve the surface structure and electrocatalytic activity of the cathode, enhance the hydrogen evolution performance of the cathode, that is, accelerate the hydrogen evolution rate and efficiency, and thus reduce the overall energy consumption of water electrolysis.

[0085] Example 2:

[0086] In industrial alkaline electrolytic cells for oxygen production, 904L stainless steel with a nickel-to-iron mass ratio of approximately 0.45, a nickel content of approximately 25%, and a molybdenum content of approximately 4% is selected as the anode substrate material. The structure is 5×5 cm. 2 The plain weave mesh is made with 160 μm wire diameter and has a mesh count of 60.

[0087] The aforementioned 904L stainless steel mesh was placed in a dual-electrode electrolytic cell for anodic oxidation, with a 5×5cm counter electrode selected. 2 A pure nickel mesh of 250 μm diameter and 50 mesh was used. A 35% KOH solution was selected as the electrolyte, the temperature was controlled at 90℃, and the voltage was cyclically applied at a rate of 0.5 V / s between 2V and 2.5V for 480 h. After stopping, the electrode was removed, rinsed with deionized water, and dried to obtain the desired 904L anode. Scanning electron microscopy (SEM) images of the 904L anode cross-section showed a nickel-rich oxide layer thickness of 1.2-1.5 μm, a nickel-iron ratio of 3, and a nickel content of approximately 74% in the metal composition.

[0088] The obtained 904L anode and a new pure nickel mesh cathode were placed in an electrolytic cell chamber containing a Zirfon 500UPT diaphragm and subjected to an electrolysis rate of 3000 A / m. 2 Operating at the specified current density, the chamber temperature was controlled at 85℃. During the 60-day test, the chamber voltage remained relatively stable at 2.09 V, and the hydrogen content in the oxygen remained consistently below 0.1%. No significant changes were observed on the cathode and anode surfaces after 60 days of reaction. However, elemental analysis of the cathode surface using energy dispersive spectroscopy revealed the presence of 0.31% molybdenum by mass. Furthermore, polarization curve tests were performed on the cathode before and after 60 days of continuous operation of the electrolytic cell chamber. The results showed that the overpotential required for the cathode decreased after 60 days of continuous operation.

[0089] Example 3:

[0090] In the application of oxygen production in industrial alkaline electrolytic cells, nickel-based alloy 800, with a nickel-to-iron mass ratio of approximately 1.1 and a nickel content of approximately 34%, is selected as the anode substrate material for industrial alkaline electrolytic cells, with a structure of 5×5cm. 2 The size is plain weave, made with 250 μm wire diameter and 40 mesh.

[0091] The aforementioned nickel-based alloy 800 metal mesh was placed in a two-electrode electrolytic cell for anodic oxidation, with a 5×5cm counter electrode selected. 2 A pure nickel mesh of a specific size was woven using 250 μm wire with a mesh size of 50. A 35% KOH solution was used as the electrolyte, the temperature was controlled at 90℃, and the voltage was cyclically applied between 2V and 2.5V at a rate of 0.5V / s for 720 hours. After stopping, the electrode was removed, rinsed with deionized water, and dried to obtain the desired 800 anode. Scanning electron microscopy (SEM) images of the anode cross-section showed a nickel-rich oxide layer thickness of approximately 1.1 μm, a nickel-iron ratio of 3.1, and a nickel content of approximately 77% in the metal composition.

[0092] The obtained 800 anode containing a nickel-rich oxide layer was placed in an electrolytic cell chamber containing a Zirfon 500UPT diaphragm, and the cathode was 5×5 cm. 2 The pure nickel mesh of this size is woven with 250 μm wire diameter and 50 mesh count, at 3000 A / m 2 The system operated at the specified current density with the chamber temperature controlled at 85°C. Within 60 days, the chamber voltage stabilized at 2.15 V, and the hydrogen content in the oxygen remained consistently below 0.1%. No significant changes were observed on the cathode and anode surfaces after 60 days of reaction.

[0093] Example 4:

[0094] In the application of oxygen production in industrial alkaline electrolyzers, nickel-based alloy 825, with a nickel-to-iron mass ratio of approximately 1.35, a nickel content of approximately 43%, and a molybdenum content of approximately 3.5%, is selected as the anode substrate material for industrial alkaline electrolyzers. The specific structure is 5×5 cm. 2 The size is plain weave, made with 250 μm wire diameter and 50 mesh.

[0095] The nickel-based alloy 825 metal mesh was placed in a two-electrode electrolytic cell for anodic oxidation, with a 5×5cm counter electrode selected. 2 A pure nickel mesh of the specified size was woven using 250 μm wire with a mesh size of 50. A 35% KOH solution was used as the electrolyte, and the temperature was controlled at 90℃ while the voltage was 2.5V for continuous operation for 600 h. After stopping, the electrode was removed, rinsed with deionized water, and dried to obtain the desired 825 anode. Scanning electron microscopy (SEM) images of the anode cross-section showed a nickel-rich oxide layer thickness of approximately 0.9 μm, a nickel-iron ratio of 3.3, and a nickel content of approximately 76% in the metal composition.

[0096] The obtained 825 anode with a nickel-rich oxide layer was placed in an electrolytic cell containing a Zirfon 500UPT diaphragm, and the cathode was 5×5 cm. 2The pure nickel mesh is woven with 250 μm wire diameter and 50 mesh count. At 3300 A / m 2 Operating at the specified current density with the chamber temperature controlled at 90℃, the chamber voltage stabilized at 2.17 V after 60 days, and the hydrogen content in the oxygen remained consistently below 0.1%. No significant changes were observed on the cathode and anode surfaces after 60 days of reaction. However, elemental analysis of the cathode surface using energy dispersive spectroscopy revealed the presence of 0.29% molybdenum by mass. Furthermore, polarization curve tests were performed on the cathode before and after 60 days of continuous operation of the electrolytic cell chamber. The results showed that the overpotential required for the cathode decreased after 60 days of continuous operation.

[0097] Example 5:

[0098] In the application of oxygen production in industrial alkaline electrolytic cells, nickel-based alloy 600 with a nickel-to-iron mass ratio of approximately 4.2 and a nickel content of approximately 60% is selected as the anode substrate material for industrial alkaline electrolytic cells, with a specification of 5×5cm. 2 The plain weave mesh is made with 250 μm wire diameter and a mesh count of 50.

[0099] The aforementioned nickel-based alloy 600 metal mesh was placed in a two-electrode electrolytic cell for anodic oxidation, with a 5×5cm counter electrode selected. 2 A pure nickel mesh of the required size was woven using 250 μm wire with a mesh size of 50. A 30% KOH solution was used as the electrolyte, and the temperature was controlled at 90℃ while the voltage was 2.8V for continuous operation for 300 h. After stopping, the electrode was removed, rinsed with deionized water, and dried to obtain the desired 600 anode. The anode cross-section was photographed using a scanning electron microscope. The thickness of the nickel-rich oxide layer on the surface was approximately 0.6 μm, the nickel-iron ratio was 5.1, and the nickel content in the metal composition was approximately 83%.

[0100] The obtained 600 anode containing a nickel-rich oxide layer was placed in an electrolytic cell chamber containing a Zirfon 500UPT diaphragm, and the cathode was 5×5 cm. 2 The pure nickel mesh is woven with 250 μm wire diameter and 50 mesh count. At 3500 A / m 2 Under the specified current density, the chamber temperature was controlled at 90℃; the chamber voltage remained stable at 2.18 V for 60 days, and the hydrogen content in the oxygen remained stable below 0.1%. No significant changes were observed on the surfaces of the cathode and anode after 60 days of reaction.

[0101] Example 6:

[0102] In the application of oxygen production in industrial alkaline electrolyzers, nickel-based alloy 601, with a nickel-to-iron mass ratio of approximately 9 and a nickel content of approximately 75%, is selected as the anode substrate material for industrial alkaline electrolyzers, with a specification of 5×5 cm. 2The size is plain weave, made with 250 μm wire diameter and 40 mesh.

[0103] The aforementioned nickel-based alloy 601 metal mesh was placed in a two-electrode electrolytic cell for anodic oxidation, with a 5×5cm counter electrode selected. 2 A pure nickel mesh of the specified size was woven using wires with a diameter of 250 μm and a mesh count of 50. A 30% KOH solution was used as the electrolyte, and the operation was maintained at 90℃ and 3.0V for 300 hours. After shutdown, the electrodes were removed, rinsed with deionized water, and dried to obtain the desired 601 anode. Scanning electron microscopy (SEM) images of the anode cross-section showed a nickel-rich oxide layer thickness of approximately 0.5 μm, a nickel-iron ratio of 10, and a nickel content of approximately 89% in the metal composition.

[0104] The obtained 601 anode with a nickel-rich oxide layer was placed in an electrolytic cell chamber containing a Zirfon 500UPT diaphragm, and the cathode was 5×5 cm. 2 The pure nickel mesh is woven with 250 μm wire diameter and 50 mesh count. At 3500 A / m 2 Under the specified current density, the chamber temperature was controlled at 90℃; the chamber voltage remained stable at 2.17 V for 60 days, and the hydrogen content in the oxygen remained stable below 0.1%. No significant changes were observed on the surfaces of the cathode and anode after 60 days of reaction.

[0105] Example 7:

[0106] The selected material is 316L stainless steel wire mesh coated with a nickel-iron alloy material with a mass ratio of approximately 5 (nickel to iron) of 100 μm and a nickel content of approximately 80%. The overall dimensions are 5 × 5 cm. 2 Plain weave mesh, 250 μm wire diameter, 40 mesh.

[0107] The aforementioned 316L stainless steel mesh, coated with a nickel-iron alloy, was placed in a two-electrode electrolytic cell for anodic oxidation. A 5×5 cm mesh was selected. 2 A pure nickel mesh with a size of 50 mesh and a wire diameter of 250 μm was used as the counter electrode. A 30% KOH solution was used as the electrolyte. The temperature was controlled at 90℃, and the voltage was cyclically applied at a rate of 1V / s from 1.9 to 2.6V for 360 h. After stopping, the electrode was removed, rinsed with deionized water, and dried to obtain the desired 316L anode. Scanning electron microscopy (SEM) of the anode cross-section showed a nickel-rich oxide layer thickness of approximately 1.2 μm. EDS elemental analysis revealed a nickel-iron ratio of 6, with nickel comprising approximately 83% of the metal composition.

[0108] The obtained anode with a nickel-rich oxide layer and a new pure nickel mesh cathode were placed in an electrolytic chamber containing a Zirfon 500UPT diaphragm and subjected to an electrolysis at 3000 A / m. 2Under the specified current density, the chamber temperature was controlled at 85℃; the chamber voltage remained stable at 2.16V for 60 days, and the hydrogen content in the oxygen remained stable below 0.1%. No significant changes were observed on the surfaces of the cathode and anode after 60 days of reaction.

[0109] Example 8

[0110] In industrial alkaline electrolytic cells for oxygen production, 314 stainless steel with a nickel-to-iron mass ratio of approximately 0.43 and a nickel content of approximately 21.2% is selected as the anode substrate material for the industrial alkaline electrolytic cell, with a specification of 5×5cm. 2 The size is plain weave, made with 200 μm wire diameter and 46 mesh.

[0111] The 314 stainless steel mesh was placed in a dual-electrode electrolytic cell for anodic oxidation, with a 5×5 cm counter electrode. 2 A pure nickel mesh of 250 μm diameter and 50 mesh was used. A 30% KOH solution was selected as the electrolyte, and the operation was maintained at 90℃ and 2.5V for 640 hours. After stopping, the electrode was removed, rinsed with deionized water, and dried to obtain the desired 314 anode with a nickel-rich surface layer. Scanning electron microscopy (SEM) images of the anode cross-section showed a nickel-rich oxide layer thickness of approximately 1.3 μm, a nickel-iron ratio of 2.85, and a nickel content of approximately 72% in the metal composition.

[0112] The obtained 314 anode with a nickel-rich oxide layer was placed in an electrolytic cell chamber containing a Zirfon 500UPT diaphragm, and the cathode was 5×5 cm. 2 The pure nickel mesh is woven with 250 μm wire diameter and 50 mesh count. At 3500 A / m 2 Under the specified current density, the chamber temperature was controlled at 90℃. Within 60 days, the chamber voltage remained relatively stable at 2.14 V, and the hydrogen content in the oxygen remained consistently below 0.1%. No significant changes were observed on the surfaces of the cathode and anode after 60 days of reaction.

[0113] Example 9

[0114] In industrial alkaline electrolytic cell oxygen production applications, 316L stainless steel with a nickel-to-iron mass ratio of approximately 0.16, a nickel content of approximately 11%, and a molybdenum content of approximately 1.4% is selected as the base material, with dimensions of 5×5 cm. 2 The steel wire mesh is woven with 250 μm wire diameter and has a mesh count of 40.

[0115] After cleaning the substrate material with acetone and ethanol, it was immersed in 1M sulfuric acid for 2 hours, then rinsed with deionized water and air-dried at room temperature.

[0116] The substrate material was then placed in a mixed solution containing 1.5 M nickel sulfate, 0.5 M sodium sulfate, 0.6 M boric acid, and 0.1 M sodium citrate. The charge was controlled at 0.003 coulombs, the current at 0.6 mA, and the deposition time at 5 s to obtain the deposited intermediate material.

[0117] Using an intermediate material as the anode and a nickel wire mesh of the same size as the cathode, the anode was placed in a 6M KOH electrolyte, with the chamber potential set at 2V and the operating temperature controlled at 85℃ for anodizing. After 480 hours of operation, the anode was removed, rinsed with deionized water, and dried at room temperature to obtain a 316L anode.

[0118] The obtained 316L anode was observed using scanning electron microscopy (SEM) and elemental analysis was performed using energy dispersive spectroscopy (EDS). The thickness of the nickel-rich oxide layer on the surface of the obtained 316L anode was approximately 1.4 μm. EDS analysis showed that the mass ratio of nickel to iron was 4, and the nickel content in the metal composition was approximately 80%. There was some elemental nickel between the surface oxide layer and the substrate layer.

[0119] The 316L anode prepared above and the new pure nickel mesh cathode were placed in an electrolytic cell chamber containing a Zirfon 500UPT diaphragm. The cathode was 5×5 cm in size. 2 The pure nickel mesh, woven with 250 μm wire and a mesh size of 50, was used under a current density of 3000 A / m², with the chamber temperature controlled at 85℃. After 20 days, the chamber voltage stabilized at 2.15 V, and the hydrogen content in the oxygen remained consistently below 0.1%. Both the cathode and anode surfaces remained smooth and crack-free after 20 days of reaction. Elemental analysis of the cathode surface using energy dispersive spectroscopy revealed the presence of 0.1% molybdenum by mass. Furthermore, polarization curve tests were performed on the cathode before and after 20 days of continuous operation of the electrolytic cell chamber. The results showed that the overpotential required for the cathode decreased after 20 days of continuous operation.

[0120] Example 10

[0121] In industrial alkaline electrolytic cell oxygen production applications, 310s stainless steel with a nickel-to-iron mass ratio of approximately 0.35 and a nickel content of approximately 20.8% is selected as the base material, with dimensions of 5×5 cm. 2 The wire mesh is sized and woven with 200 μm wire diameter and 50 mesh.

[0122] After cleaning the substrate material with ethanol and acetone, it was immersed in 1M sulfuric acid for 1 hour, then rinsed with deionized water and air-dried at room temperature.

[0123] The substrate material was then placed in a mixed solution containing 1.5 M nickel sulfate, 0.5 M sodium sulfate, 0.6 M boric acid, and 0.1 M sodium citrate. The charge was controlled at 0.002 coulombs, the current at 0.4 mA, and the deposition time at 5 s to obtain the deposited intermediate material.

[0124] Using an intermediate material as the anode and a nickel wire mesh of the same size as the cathode, the electrode was placed in a 7M KOH electrolyte. The electrolytic cell temperature was controlled at 85℃, and the electrode was set at 2.6 V for anodizing. After running for 480 hours, the electrode was removed, rinsed with deionized water, and dried at room temperature to obtain the target 310s anode.

[0125] The obtained 310s anode was observed using scanning electron microscopy (SEM) and elemental analysis was performed using energy dispersive spectroscopy (EDS). The thickness of the nickel-rich oxide layer on the surface was approximately 1.2 μm. EDS analysis showed that the mass ratio of nickel to iron was 4.5, and nickel accounted for 82% of the metal elements. A small amount of elemental nickel was found between the surface oxide layer and the substrate layer.

[0126] The target 310s anode prepared above and the new pure nickel mesh cathode were placed in an electrolytic cell chamber containing a Zirfon 500UPT diaphragm. The cathode was 5×5 cm in size. 2 The pure nickel mesh was woven with 250 μm wire and 50 mesh, operating at a current density of 3000 A / m², with the chamber temperature controlled at 85℃. After 30 days, the chamber voltage stabilized at approximately 2.16 V, and the hydrogen content in the oxygen remained consistently below 0.1%. After 20 days of reaction, both the cathode and anode surfaces remained smooth and crack-free.

[0127] Comparative Example 1:

[0128] In the application of oxygen production in industrial alkaline electrolyzers, pure nickel mesh is selected as the anode of the industrial alkaline electrolyzer, with a structure of 5×5 cm. 2 The plain weave screen is 250 μm in diameter and has a mesh count of 50. The cathode is 5 × 5 cm. 2 The pure nickel mesh of this size is woven with a wire diameter of 250 μm and a mesh count of 50.

[0129] The pure nickel mesh anode and cathode were placed in an electrolytic cell chamber containing a Zirfon 500UPT diaphragm, and the electrolysis was performed at 3000 A / m. 2 The chamber temperature was controlled at 85℃ for 10 days under the current density.

[0130] Figure 8 This is a graph showing the voltage change in the cell chamber of the pure nickel mesh anode in Comparative Example 1 of this application after working for 10 days in the electrolytic cell.

[0131] like Figure 8 As shown, during the 10-day continuous operation of the electrolytic cell chamber, the chamber voltage experienced a power outage on the 5th day. After 10 days, the chamber voltage remained at around 2.3 V without any significant upward or downward trend. This comparison illustrates that when using pure nickel mesh as the anode material, the chamber potential is high and the energy consumption for electrolytic oxygen production is large.

[0132] During 10 days of continuous operation, the hydrogen content in the oxygen in the electrolytic cell chamber remained below 0.1%, and the surfaces of both the cathode and anode remained smooth and free of cracks.

[0133] Comparative Example 2:

[0134] In the application of oxygen production in industrial alkaline electrolytic cells, 304 stainless steel with a nickel-to-iron mass ratio of approximately 0.11 and a nickel content of approximately 8% is selected as the anode material for the industrial alkaline electrolytic cell, with a structure of 5×5 cm. 2 The plain weave screen is woven with 250 μm wire diameter and has a mesh count of 40. The cathode is 5×5 cm. 2 The pure nickel mesh is woven with 250 μm wire diameter and has a mesh count of 50.

[0135] A 304 stainless steel mesh and a cathode were placed in an electrolytic cell chamber containing a Zirfon 500UPT diaphragm, and the electrolysis was performed at 3000 A / m. 2 It was operated at current density for 20 days, with the chamber temperature controlled at 85℃.

[0136] Figure 9 The voltage change curve of the 304 stainless steel in Comparative Example 2 of this application after working in the electrolytic cell for 20 days is shown.

[0137] like Figure 9 As shown, during the 20-day continuous operation of the electrolytic cell, the cell voltage fluctuated significantly, with a decrease in voltage density starting from the 10th day. After 20 days, the cell voltage remained at approximately 1.9 V.

[0138] Figure 10 The graph shows the change in hydrogen content in oxygen of stainless steel 304 (Comparative Example 2) after it has been working in an electrolytic cell chamber for 20 days.

[0139] like Figure 10 As shown, the hydrogen content in the oxygen in the electrolytic cell chamber gradually increased over 20 days of continuous operation, with a significant increase starting on the 7th day. On the 14th day, the hydrogen content in the oxygen increased to 24%, while the lower explosive limit of hydrogen in oxygen was 4%, indicating a significant safety hazard.

[0140] Figure 11The images shown are scanning electron microscope (SEM) images of the anode and cathode material surfaces after 20 days of operation of the electrolytic cell chamber in Comparative Example 2 of this application. (a) is a scanning electron microscope image of the anode surface; (b) is a scanning electron microscope image of the cathode surface; and (c) is a magnified view of (b).

[0141] like Figure 11 As shown, after 20 days of continuous operation in the electrolytic cell chamber, the oxide layer on the anode surface showed obvious cracks, and correspondingly, obvious metal deposition appeared on the cathode surface.

[0142] Figure 12 EDS energy spectrum of the anode surface of stainless steel 304 in Comparative Example 2 of this application after working in an electrolytic cell chamber for 20 days;

[0143] like Figure 12 As shown, EDS analysis revealed that the nickel-iron ratio in the nickel-rich oxide layer on the surface of the stainless steel 304 anode in Comparative Example 2 was approximately 0.9 after 20 days in the electrolytic cell.

[0144] Comparative Example 3

[0145] In the application of oxygen production in industrial alkaline electrolytic cells, 316L stainless steel with a nickel-to-iron mass ratio of approximately 0.16, a nickel content of approximately 11%, and a molybdenum content of approximately 1.4% is selected as the anode material for the industrial alkaline electrolytic cell, with a structure of 5*5 cm. 2 The mesh is a plain weave, made with 250 μm wire diameter and a mesh count of 40. The cathode is 5*5 cm. 2 The pure nickel mesh is made of 250 μm wire with a mesh count of 50.

[0146] The 316L stainless steel anode and cathode were placed in an electrolytic cell chamber containing a Zirfon 500UPT diaphragm, and subjected to an electrolytic voltage of 3000 A / m. 2 It was operated at current density for 20 days, with the chamber temperature controlled at 85℃.

[0147] After 20 days of continuous operation in the electrolytic cell, the cell voltage remained at approximately 2.08 V, and the hydrogen content in the oxygen remained below 0.1%, although it showed an increasing trend. Significant cracking of the oxide layer on the anode surface was observed, and corresponding metal deposition appeared on the cathode surface. EDS analysis revealed that the nickel-iron ratio of the anode surface elements in Comparative Example 3 after 20 days of operation was approximately 1.5.

[0148] Comparative Example 4

[0149] In industrial alkaline electrolytic cell oxygen production applications, 310s stainless steel with a nickel-to-iron mass ratio of approximately 0.35 and a nickel content of approximately 20.8% is selected as the base material, with dimensions of 5×5 cm. 2The wire mesh is sized and woven with 200 μm wire diameter and 50 mesh.

[0150] A 310s stainless steel mesh was used directly as the anode, and a nickel wire mesh of the same size was used as the cathode. The mesh was placed in a 7M KOH electrolyte, the cell temperature was controlled at 85℃, and the electrode voltage was set to 2.6 V for anodizing. After 640 hours of operation, the mesh was removed, rinsed with deionized water, and dried at room temperature to obtain the target 310s anode.

[0151] The obtained 310s anode was observed using scanning electron microscopy (SEM) and elemental analysis was performed using energy dispersive spectroscopy (EDS). A nickel-rich layer was found on the surface, but its distribution was uneven and contained some gaps. EDS analysis of the nickel-rich layer region showed that the mass ratio of nickel to iron was approximately 2.5, and nickel accounted for 66% of the metallic elements.

[0152] The target 310s anode prepared above and the new pure nickel mesh cathode were placed in an electrolytic cell chamber containing a Zirfon 500UPT diaphragm. The cathode was 5×5 cm in size. 2 The pure nickel mesh was woven with 250 μm wire diameter and 50 mesh size, operating at a current density of 3000 A / m², with the chamber temperature controlled at 85℃. After 30 days, the chamber voltage reached 2.18 V and showed a continuous increasing trend. The hydrogen content in the oxygen remained basically below 0.1%, but also showed an increasing trend. After the reaction, a small amount of deposits could be observed on the cathode surface, and the oxide layer on the anode surface thickened.

[0153] According to the data in Table 1:

[0154] First, by comparing Examples 1-10 with Comparative Examples 1-4, it can be seen that, compared with anodes made of pure nickel substrate materials, the anode catalyst materials provided in the embodiments of the present invention can not only maintain the hydrogen content in oxygen at a low level (<0.1%) and the anode surface morphology remain stable during long-term operation, but also reduce the anode overpotential, thereby reducing the energy consumption of water electrolysis.

[0155] Secondly, as shown in Examples 1-8, for stainless steel or nickel-based alloys with high nickel content (Ni / Fe mass ratio of 0.4-10, nickel content of 21%-80%), they can be directly anodized in an alkaline electrolyte to obtain an anode catalyst. Therefore, this method is suitable for preparing anode catalysts via in-situ anodization, where the stainless steel or nickel-based alloy can first undergo anodization to generate the anode catalyst, which can then be used as an anode catalyst in that system, eliminating the need to first prepare the anode catalyst in one reaction system and then transfer it to another for use as an anode catalyst.

[0156] A comparison of Examples 9-10 and Comparative Examples 3-4 reveals that for stainless steel with high iron content (Ni / Fe mass ratio of 0.15 or higher but less than 0.4, and nickel content of 10% to 21%), while a low anodic overpotential (1.9V) can be achieved when used directly as an anode catalyst, the hydrogen content in the oxygen reaches the explosion limit (24%) during long-term operation, posing a safety hazard. Furthermore, prolonged anodizing leads to surface cracking of the anode, making it difficult to form a stable nickel-rich oxide layer, thus reducing electrolysis efficiency. However, by depositing a nickel-containing metal layer on its surface to increase the nickel content of the substrate, followed by anodizing, a long-term stable nickel-rich oxide layer can be constructed on the substrate surface.

[0157] Finally, the data from Examples 1-2, 4, and 9 show that when the substrate material contains an appropriate amount of molybdenum, trace amounts of molybdenum will dynamically deposit on the cathode side, improving the surface structure and electrocatalytic activity of the cathode, thereby enhancing the hydrogen evolution performance of the cathode, that is, accelerating the hydrogen evolution rate and efficiency, and reducing the overall energy consumption of water electrolysis.

[0158] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of this application. It should be understood that the above descriptions are merely specific embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

[0159] Table 1

[0160]

Claims

1. An anode catalyst material, comprising: The substrate is an alloy containing nickel and iron, wherein the nickel content of the substrate is 10% to 80% by mass, and the mass ratio of nickel to iron in the substrate is 0.15 to 10; and A nickel-rich oxide layer is coated on the surface of the substrate, wherein the nickel-rich oxide layer comprises nickel oxide and / or nickel hydroxide, and the mass content of nickel in the metal component of the nickel-rich oxide layer is greater than 70%.

2. The anode catalyst material according to claim 1, wherein: The mass ratio of nickel to iron in the nickel-rich oxide layer is greater than 2.5; and / or The thickness of the nickel-rich oxide layer is 0.5~5 μm.

3. The anode catalytic material of claim 1, wherein, The thickness of the nickel-rich oxide layer is 0.5~1.5 μm.

4. The anode catalytic material of claim 1, 2, or 3, wherein, The mass ratio of nickel to iron in the substrate is greater than 0.15 and less than 0.4, and the mass content of nickel is 10% to 21%.

5. The anode catalyst material according to claim 1, 2 or 3, wherein, There is elemental nickel or a nickel-based alloy between the substrate and the nickel-rich oxide layer.

6. The anode catalyst material according to claim 1, 2 or 3, wherein, The mass ratio of nickel to iron in the substrate is 0.4 to 10.

7. The anode catalyst material according to claim 1, 2 or 3, wherein, The total mass content of elements other than nickel and iron in the substrate is less than or equal to 30%; The other elements include molybdenum, and the mass content of molybdenum is less than 5%.

8. A method for preparing an anode catalyst material, comprising: A nickel-containing metal layer is deposited on the surface of a substrate to obtain an intermediate, wherein the substrate is an alloy containing nickel and iron, the nickel content of the substrate is 10% to 80% by mass, and the mass ratio of nickel to iron in the substrate is 0.15 to 10. Using the intermediate as the anode, anodic oxidation is performed in an alkaline electrolyte to form a nickel-rich oxide layer, thereby obtaining the anode catalyst material.

9. The preparation method according to claim 8, wherein: The deposition of a nickel-containing metal layer on the surface of the substrate includes: using the substrate as a cathode and performing electrodeposition in an electrolyte containing a nickel source; and / or The conditions for anodizing include: using a 10% to 50% NaOH or KOH electrolyte, at a temperature of 25 to 95°C, applying a voltage of 1.5 to 3.5 V for 72 to 1440 hours.

10. The preparation method according to claim 8 or 9, wherein, There is elemental nickel or a nickel-based alloy between the substrate and the nickel-rich oxide layer.

11. The preparation method according to claim 10, wherein, The mass ratio of nickel to iron in the substrate is greater than 0.15 and less than 0.4, and the mass content of nickel is 10% to 21%.

12. A method for preparing an anode catalyst material, comprising: A substrate is provided, wherein the mass ratio of nickel to iron in the substrate is 0.4 to 10, and the mass content of nickel is 21% to 80%. Using the substrate as the anode, anodic oxidation is performed in an alkaline electrolyte to obtain the anode catalyst material.

13. The application of an anode catalyst material as described in any one of claims 1 to 7 as an anode in the field of electrolytic oxygen production.

14. The application of a stainless steel or nickel-based alloy in the preparation of anode catalyst materials, wherein, The mass ratio of nickel to iron in the stainless steel or nickel-based alloy is 0.4 to 10, and the mass content of nickel is 21% to 80%.

15. The application according to claim 14, wherein, The anode catalyst material is used in the alkaline water electrolysis reaction to produce oxygen.

16. The application according to claim 14, wherein, The stainless steel or nickel-based alloy is used to prepare the anode catalyst material by in-situ anodic oxidation.

17. The application according to claim 16, wherein, The stainless steel or nickel-based alloy is anodized in an equipment that generates oxygen by electrolysis with an alkaline electrolyte.

18. An electrolytic cell, characterized in that: The electrolytic cell includes the anode catalyst material according to any one of claims 1 to 7.

Images