Electrolytic cell, anode catalytic material, preparation method therefor, and use thereof

Abstract

The present application provides an electrolytic cell, an anode catalytic material, a preparation method therefor, and a use thereof. The anode catalytic material in the present application comprises: a substrate, which is an alloy comprising nickel and iron elements; and a nickel-rich oxide layer, which covers the surface of the substrate, wherein the nickel-rich oxide layer comprises nickel oxide and / or nickel hydroxide, and the mass content of nickel element in metal components of the nickel-rich oxide layer is greater than 70%. The anode catalytic material uses a nickel-iron alloy as a substrate, and the addition of iron element can effectively reduce the oxygen evolution overpotential of the substrate material; the nickel-rich oxide layer covering the surface of the substrate can passivate the substrate, and inhibit the dissolution of metal ions, preventing collapse of the skeleton structure of the alloy substrate, thereby maintaining mechanical stability; when the nickel-rich oxide layer is used as an anode, the thickness of the nickel-rich oxide layer does not increase significantly, thus not affecting the catalytic performance thereof; the nickel oxide and / or nickel hydroxide contained in the nickel-rich oxide layer and nickel iron hydroxide which may also be contained therein are also used as active components, thereby further ensuring the catalytic activity of the material.

Description

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

[0001] Cross-reference to related applications

[0002] This application claims priority to Chinese Patent Application No. 2024111865850, filed on August 27, 2024, entitled "An Electrolyzer, Anode Catalyst Material and Its Preparation Method and Application", the entire contents of which are incorporated herein by reference. Technical Field

[0003] 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

[0004] 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 (1.6–3V) while continuously resisting the release of oxygen. Therefore, the anode electrode material must possess good electrochemical activity and resistance to alkali and oxygen corrosion.

[0005] 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

[0006] 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 preparing the same, and its application.

[0007] To achieve the above objectives, the technical solution of this application is as follows:

[0008] 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%.

[0009] 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.

[0010] 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.

[0011] 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.

[0012] 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%.

[0013] 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.

[0014] According to the anodic catalyst materials, their preparation methods, and applications provided in this application, firstly, an alloy containing nickel and iron is used as the substrate for the anodic catalyst material. A nickel-rich oxide layer can be coated onto the substrate surface through anodic oxidation, thereby reducing the anodic overpotential and thus lowering the energy consumption for water electrolysis. Secondly, by controlling the nickel-iron content ratio 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 catalyst material and improving the purity of the produced oxygen. Especially for high nickel-iron ratio alloys, they can be directly anodicized to obtain the anodic catalyst material, and this method is suitable for preparing anodic catalyst materials via in-situ anodic oxidation. For low nickel-iron ratio alloys, a nickel-containing metal layer can be deposited on their surface. After increasing the nickel content on the substrate surface, anodic oxidation can then be performed, similarly constructing a long-term structurally stable nickel-rich oxide layer on the substrate surface. Furthermore, when the alloy material contains an appropriate amount of molybdenum, trace amounts of molybdenum will dynamically deposit on the cathode side, improving the cathode's surface structure and electrocatalytic activity, thereby enhancing the cathode's catalytic performance and reducing the overall electrolysis energy consumption. The electrolyzer of this application has the same or similar advantages as the related technologies and the aforementioned anode catalyst materials, which will not be elaborated here. Attached Figure Description

[0015] 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:

[0016] Figure 1 is a schematic flowchart of the preparation method of the anode catalyst material according to an embodiment of this application;

[0017] Figure 2 is a cross-sectional scanning electron microscope (SEM) image of the 904L anode obtained in Example 1 of this application;

[0018] Figure 3 is a graph showing the voltage change in the cell chamber of the 904L anode obtained in Example 1 of this application after working in the electrolytic cell for 20 days.

[0019] Figure 4 shows the change in hydrogen content in oxygen of the 904L anode obtained in Example 1 of this application after working in the electrolytic cell for 15 days.

[0020] Figure 5 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;

[0021] Figure 6 is a scanning electron microscope 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;

[0022] Figure 7 shows the cathode polarization curves of the electrolytic cell chamber in Example 1 of this application before and after 20 days of continuous operation.

[0023] Figure 8 is a graph showing the voltage change of the pure nickel mesh anode of Comparative Example 1 of this application after working in the electrolytic cell for 10 days.

[0024] Figure 9 is a graph showing the voltage change of the 304 stainless steel in the electrolytic cell chamber of Comparative Example 2 of this application after working for 20 days.

[0025] Figure 10 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.

[0026] Figure 11 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;

[0027] Figure 12 shows the EDS energy spectrum of the anode surface of the 304 stainless steel of Comparative Example 2 of this application after working in the electrolytic cell chamber for 20 days. Detailed Implementation

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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 the form of its high-valence oxygen ion (CrO4). 2- or Cr2O7 2- It exists in the electrolyte; manganese initially exists as MnO4. 2- It dissolves in the form of MnO2 and will later be deposited on the cathode; 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.

[0033] Therefore, this application 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 potentially 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.

[0034] 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%.

[0035] 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.).

[0036] 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.

[0037] 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.

[0038] 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%.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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%.

[0043] 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.

[0044] 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., with a total mass content of, for example, 30%, 25%, 20%, 10%, or 5%; the other elements preferably include molybdenum, with a molybdenum mass content of less than 5%, for example, 4%, 3%, 2%, 1%, or 0.5%.

[0045] 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.

[0046] 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.

[0047] 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%.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] According to another aspect of this application, a method for preparing the above-mentioned anode catalyst material is provided. Figure 1 is a schematic flowchart of the preparation method of the anode catalyst material according to an embodiment of this application. As shown in Figure 1, the preparation method of this application may include the following steps S101 to S102.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] 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 ) / unit molar atomic weight (6.02×10 23 );

[0060] 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 ) / unit 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).

[0061] 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 15 min to 24 h, rinsed with pure water, and dried in an environment of room temperature to 50°C.

[0062] According to an embodiment of this application, in step S102, the conditions for anodizing include: using a NaOH or KOH electrolyte of 10% to 50% (e.g., 10%, 20%, 25%, 30%, 35%, 40%, 50%), 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 3.5V (e.g., 1.5V, 1.8V, 2.0V, 2.2V, 2.5V, 3.0V, 3.5V), 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).

[0063] 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.

[0064] 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 over a 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.

[0065] 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.

[0066] 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 to 210 mV, thereby achieving lower energy consumption for water electrolysis oxygen production. The material cost is also reduced by 25 to 75% compared to pure nickel anode materials.

[0067] 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%).

[0068] 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.

[0069] 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, wherein the mass ratio of nickel to iron is ≥0.4 and the mass content of nickel is ≥21%.

[0070] 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.

[0071] 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 an anodic catalyst. More preferably, the stainless steel or nickel-based alloy is anodized in an oxygen-generating device using an alkaline electrolyte, wherein the oxygen-generating device 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 0.1 MPa-3 MPa, preferably 1-2 MPa; the chamber voltage is 2V-2.8V, and the temperature is 75℃-90℃.

[0072] 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), etc.

[0073] The present application is further illustrated below through embodiments and related test experiments. In the detailed description below, numerous specific details are set forth for ease of explanation to provide a comprehensive understanding of the embodiments of the present application. However, it is apparent that one or more embodiments may be implemented without these specific details. Moreover, the details in the following embodiments can be arbitrarily combined to form other feasible embodiments without conflict.

[0074] Example 1:

[0075] 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 plain weave mesh is made with 250μm wire diameter and has a mesh count of 50.

[0076] The aforementioned 904L stainless steel mesh was placed in the electrolytic cell, and a 5×5cm electrode was selected. 2 A pure nickel mesh of a specific size, woven with 250μm wire diameter and 50 mesh count, 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.

[0077] 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 3000A / m³. 2 .

[0078] Figure 2 is a cross-sectional view of the 904L anode obtained in Example 1 of this application. Elemental analysis of the nickel-rich oxide layer (gray box area) using energy dispersive spectroscopy (EDS) revealed a nickel-iron ratio of 2.9 and a Ni content of 71% among the metallic elements (Ni, Fe, Cr, Mn, Mo). As shown in Figure 2, the thickness of the nickel-rich oxide layer is approximately 1 μm.

[0079] Figure 3 is a graph showing the voltage change of the 904L anode with a nickel-rich oxide layer obtained in Example 1 of this application after working in the electrolytic cell for 20 days.

[0080] As shown in Figure 3, 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 2.14V, 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.

[0081] Figure 4 shows 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.

[0082] As shown in Figure 4, the hydrogen content in the oxygen in the electrolytic cell remained at a low level for 15 consecutive days, basically below 0.1%. Using this anode, the system can operate safely and stably for a long time.

[0083] Figure 5 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 for 20 days; as can be seen from Figure 7, the nickel-rich oxide layer on the surface of the anode did not change significantly after working for 20 days, and the thickness was still about 1 μm.

[0084] Figure 6 is 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, where (a) is a scanning electron microscope image of the cathode surface and (b) is a partial magnified view of (a).

[0085] As shown in Figure 6, 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.

[0086] 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. As shown in Figure 7, under the same current density, the overpotential required for the cathode after 20 days of continuous operation of the electrolytic cell 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.

[0087] Example 2:

[0088] 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 5×5cm. 2 The plain weave mesh is made with 160μm wire diameter and has a mesh count of 60.

[0089] 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, woven with 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 2 V and 2.5 V for 480 hours. 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.

[0090] 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 2.09V, 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.

[0091] Example 3:

[0092] In the application of oxygen production in industrial alkaline electrolytic cells, a 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 250μm wire diameter and 40 mesh.

[0093] 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. 2A pure nickel mesh of a specific size was used, woven with 250 μm wire diameter and a mesh size of 50. A 35% KOH solution was selected 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.

[0094] 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 5×5cm. 2 The pure nickel mesh of this size is woven with 250μm wire diameter and 50 mesh count, at 3000A / 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 2.15V, 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.

[0095] Example 4:

[0096] 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 5×5cm. 2 The plain weave mesh is made with 250μm wire diameter and has a mesh count of 50.

[0097] 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 hours. 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.

[0098] 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 5×5cm. 2 The pure nickel mesh is woven with 250μm wire diameter and 50 mesh count. At 3300A / m 2Operating at the specified current density with the chamber temperature controlled at 90℃, the chamber voltage stabilized at 2.17V 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 required overpotential for the cathode decreased after 60 days of continuous operation.

[0099] Example 5:

[0100] In industrial alkaline electrolytic cells for oxygen production, a 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 the industrial alkaline electrolytic cell, with a specification of 5×5cm. 2 The plain weave mesh is made with 250μm wire diameter and has a mesh count of 50.

[0101] 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 hours. After stopping, the electrodes were removed, rinsed with deionized water, and dried to obtain the desired 600 anode. Scanning electron microscopy (SEM) images of the anode cross-section showed a nickel-rich oxide layer thickness of approximately 0.6 μm, a nickel-iron ratio of 5.1, and a nickel content of approximately 83% in the metallic composition.

[0102] 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 5×5cm. 2 The pure nickel mesh is woven with 250μm wire diameter and 50 mesh count. At 3500A / m 2 Under the specified current density, the chamber temperature was controlled at 90℃; the chamber voltage remained stable at 2.18V 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.

[0103] Example 6:

[0104] In the application of oxygen production in industrial alkaline electrolytic cells, 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 electrolytic cells, with a specification of 5×5cm. 2 The size is plain weave, made with 250μm wire diameter and 40 mesh.

[0105] 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 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 maintained at 3.0V for 300 hours. After the operation was stopped, the electrode was 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.

[0106] 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 5×5cm. 2 The pure nickel mesh is woven with 250μm wire diameter and 50 mesh count. At 3500A / m 2 Under the specified current density, the chamber temperature was controlled at 90℃; the chamber voltage remained stable at 2.17V 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.

[0107] Example 7:

[0108] 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) and a nickel content of approximately 80%. The overall dimensions are 5×5cm. 2 Plain weave mesh, 250μm wire diameter, 40 mesh.

[0109] The aforementioned 316L stainless steel mesh, coated with a nickel-iron alloy, was placed in a two-electrode electrolytic cell for anodic oxidation. A 5×5cm mesh was selected. 2 A pure nickel mesh with a mesh size of 50 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 circulated at a rate of 1 V / s between 1.9 and 2.6 V for 360 hours continuously. 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.

[0110] 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. 2 Under 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.

[0111] Example 8

[0112] 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 200μm wire diameter and 46 mesh.

[0113] The 314 stainless steel mesh was placed in a dual-electrode electrolytic cell for anodic oxidation, with a 5×5cm electrode selected as the 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 electrodes were 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.

[0114] 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 5×5cm. 2 The pure nickel mesh is woven with 250μm wire diameter and 50 mesh count. At 3500A / m 2 Under the specified current density, the chamber temperature was controlled at 90℃. Within 60 days, the chamber voltage remained relatively stable at 2.14V, and the hydrogen content in the oxygen remained consistently below 0.1%. No significant changes were observed on the surfaces of both the cathode and anode after 60 days of reaction.

[0115] Example 9

[0116] In industrial alkaline electrolytic cells for oxygen production, 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 5×5cm. 2 The wire mesh is 250μm in diameter and has a mesh count of 40.

[0117] 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.

[0118] 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 was set to 0.6 mA, and the deposition time was set to 5 s to obtain the deposited intermediate material.

[0119] 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.

[0120] 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.

[0121] 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 5×5cm in size. 2 The pure nickel mesh of this size is woven with 250μm wire diameter and 50 mesh count, at 3000A / m 2 The system operated at the specified current density with the chamber temperature controlled at 85℃. After 20 days, the chamber voltage stabilized at 2.15V, 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.

[0122] Example 10

[0123] In industrial alkaline electrolytic cells for oxygen production, 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 5×5cm. 2 The steel wire mesh is woven with 200μm wire diameter and has a mesh count of 50.

[0124] 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.

[0125] 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 was set to 0.4 mA, and the deposition time was set to 5 s to obtain the deposited intermediate material.

[0126] 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 voltage was set at 2.6V 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.

[0127] 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.

[0128] 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 5×5cm in size. 2 The pure nickel mesh of this size is woven with 250μm wire diameter and 50 mesh count, at 3000A / m 2 Operating at the specified current density, the chamber temperature was controlled at 85℃. After 30 days, the chamber voltage stabilized at approximately 2.16V, 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.

[0129] Comparative Example 1:

[0130] In the application of oxygen production in industrial alkaline electrolytic cells, pure nickel mesh is selected as the anode of the industrial alkaline electrolytic cell, with a structure of 5×5cm. 2 The mesh is a plain weave, made with 250μm wire diameter and a mesh count of 50. The cathode is 5×5cm. 2 The pure nickel mesh of this size is woven with a wire diameter of 250μm and a mesh count of 50.

[0131] 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.

[0132] Figure 8 is a graph showing the voltage change in the cell of the pure nickel mesh anode of Comparative Example 1 of this application after working in the electrolytic cell for 10 days.

[0133] As shown in Figure 8, during the 10-day continuous operation of the electrolytic cell, the cell voltage experienced a power outage on the 5th day. After 10 days, the cell voltage remained at around 2.3V without any significant upward or downward trend. This comparison illustrates that when using pure nickel mesh as the anode material, the cell potential is high and the energy consumption for electrolytic oxygen production is large.

[0134] During 10 days of continuous operation, the hydrogen content in the oxygen in the electrolytic cell was maintained at less than 0.1%, and the surfaces of both the cathode and anode remained flat and crack-free.

[0135] Comparative Example 2:

[0136] 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 5×5cm. 2 The mesh is a plain weave, made with 250μm wire diameter and a mesh count of 40. The cathode is 5×5cm. 2 The pure nickel mesh is woven with 250μm wire diameter and has a mesh count of 50.

[0137] 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℃.

[0138] Figure 9 is a graph showing the voltage change of the 304 stainless steel in Comparative Example 2 of this application during 20 days of operation in the electrolytic cell.

[0139] As shown in Figure 9, during the 20-day continuous operation of the electrolytic cell, the voltage in the small chamber fluctuated significantly, with a decrease in electrical density starting from the 10th day. After 20 days, the voltage in the small chamber remained at approximately 1.9V.

[0140] Figure 10 shows the change in hydrogen content in oxygen of stainless steel 304 (Comparative Example 2) after working in an electrolytic cell chamber for 20 days.

[0141] As shown in Figure 10, the hydrogen content in the oxygen in the electrolytic cell chamber gradually increased over 20 days of continuous operation. The increase became more pronounced after the 7th day, and reached 24% on the 14th day. The lower limit for hydrogen explosion in oxygen is 4%, indicating a significant safety hazard.

[0142] Figure 11 shows scanning electron microscope (SEM) images of the anode and cathode material surfaces after 20 days of operation in the electrolytic cell chamber of Comparative Example 2 of this application, where (a) is an SEM image of the anode surface; (b) is an SEM image of the cathode surface; and (c) is a magnified view of (b).

[0143] As shown in Figure 11, after the electrolytic cell chamber has been running continuously for 20 days, the oxide layer on the anode surface has obvious cracks, and correspondingly, obvious metal deposition has also appeared on the cathode surface.

[0144] Figure 12 shows the EDS energy spectrum of the anode surface of the stainless steel 304 of Comparative Example 2 of this application after working in the electrolytic cell chamber for 20 days.

[0145] As shown in Figure 12, 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.

[0146] Comparative Example 3

[0147] 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*5cm. 2 The plain weave screen is made with 250μm wire diameter and a mesh count of 40. The cathode is 5*5cm. 2 The pure nickel mesh is made of 250μm wire with a mesh count of 50.

[0148] The 316L stainless steel 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 It was operated at current density for 20 days, with the chamber temperature controlled at 85℃.

[0149] After 20 days of continuous operation in the electrolytic cell, the cell voltage remained at approximately 2.08V, 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.

[0150] Comparative Example 4

[0151] In industrial alkaline electrolytic cells for oxygen production, 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 5×5cm. 2 The steel wire mesh is woven with 200μm wire diameter and has a mesh count of 50.

[0152] 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 electrolytic cell temperature was controlled at 85℃, and the electrode voltage was set to 2.6V 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.

[0153] 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, with nickel accounting for 66% of the total metallic element content.

[0154] 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 5×5cm in size. 2 The pure nickel mesh of this size is woven with 250μm wire diameter and 50 mesh count, at 3000A / m 2 Operating at current density, the chamber temperature was controlled at 85℃. After 30 days, the chamber voltage reached 2.18V and showed a continuous upward trend. The hydrogen content in the oxygen remained below 0.1% and also showed an upward 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.

[0155] According to the data in Table 1:

[0156] 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 this application can not only maintain the hydrogen content in oxygen at a low level (<0.1%) and keep the anode surface morphology stable during long-term operation, but also reduce the anode overpotential, thereby reducing the energy consumption of water electrolysis.

[0157] Secondly, as shown in Examples 1-8, stainless steel or nickel-based alloys with high nickel content (Ni / Fe mass ratio of 0.4-10, nickel content of 21%-80%) 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.

[0158] A comparison of Examples 9-10 and Comparative Examples 3-4 reveals that for stainless steel with a high iron content (Ni / Fe mass ratio of 0.15 or higher but less than 0.4, and nickel content of 10%–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.

[0159] 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.

[0160] 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.

Claims

1. An anode catalyst material, comprising: The base is an alloy containing nickel and iron. as well as 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, preferably 0.5–1.5 μm.

3. The anode catalyst material according to claim 1 or 2, wherein, The mass ratio of nickel to iron in the substrate is 0.15 to 10, and the mass content of nickel is not less than 10%, preferably 10% to 80%.

4. The anode catalyst material according to any one of claims 1-3, 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 any one of claims 1-3, wherein, The mass ratio of nickel to iron in the substrate is 0.4 to 10; the mass content of nickel is 21% to 80%.

6. The anode catalyst material according to any one of claims 1-5, wherein, There is elemental nickel or a nickel-based alloy between the substrate and the nickel-rich oxide layer.

7. The anode catalyst material according to any one of claims 1-6, 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. 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%–50% NaOH or KOH electrolyte, at a temperature of 25–95°C, applying a voltage of 1.5–3.5V for 72–1440 hours.

10. The preparation method according to claim 8 or 9, wherein, The mass ratio of nickel to iron in the substrate is 0.15 to 10, and the mass content of nickel is 10% to 80%; preferably, 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%. Alternatively, there may be elemental nickel or a nickel-based alloy between the substrate and the nickel-rich oxide layer.

11. 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.

12. 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.

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

14. The application according to claim 13, wherein, The anode catalyst material is used in the alkaline water electrolysis reaction to produce oxygen.

15. The application according to claim 13, wherein, The stainless steel or nickel-based alloy is prepared by in-situ anodizing, preferably by anodizing in an equipment for generating oxygen by electrolysis with an alkaline electrolyte.

16. An electrolytic cell, wherein, The electrolytic cell includes the anode catalyst material according to any one of claims 1 to 7.

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