Electrolytic bath, anode catalytic material and preparation method and application of anode catalytic material

Abstract

The invention provides an electrolytic bath, an anode catalytic material and a preparation method and application of the anode catalytic material, and the anode catalytic material comprises a substrate which is an alloy containing a nickel element and an iron element; the surface of the substrate is coated with the nickel-rich oxide layer, the nickel-rich oxide layer comprises nickel oxide and / or nickel hydroxide, and the mass content of nickel elements in metal components of the nickel-rich oxide layer is larger than 70%.

Description

Technical Field

[0001] The present application relates to the technical field of electrolytic oxygen production, in particular to the technical field of electrolytic water oxygen production. Specifically, the present application relates to an electrolytic cell, an anode catalytic material, and a preparation method and application thereof. Background Art

[0002] In the alkaline water electrolysis oxygen production technology, a high-concentration alkaline solution is generally used as the electrolyte in the electrolyzer, and it is operated at a temperature of 75-90°C. In this environment, the kinetic reaction of the oxygen evolution reaction on the anode side is slow, which is the bottleneck restricting the alkaline water electrolysis oxygen production. In addition, the anode side chamber of the electrolyzer needs to withstand high voltage (1.6~3 V) and continue to tolerate the continuous precipitation of oxygen. Therefore, the anode side electrode material is required to have good electrochemical activity, as well as alkali and oxygen corrosion resistance.

[0003] In the process of realizing the concept of this application, the inventors found that there are at least the following problems in the related technology: the related technology uses metal nickel with good alkali corrosion resistance as the anode material, but the oxygen evolution performance of pure nickel material is limited, resulting in a high overpotential of the anode of the electrolytic cell, affecting the overall electrolysis efficiency. Summary of the invention

[0004] In view of this, in order to at least partially solve at least one of the above-mentioned technical problems, the present application provides an anode catalyst material and a preparation method and application thereof.

[0005] In order to achieve the above purpose, the technical solution of this application is as follows:

[0006] According to an embodiment of one aspect of the present application, an anode catalytic material is provided, comprising: a substrate, which is an alloy containing nickel and iron elements; and a nickel-rich oxide layer 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 an embodiment of another aspect of the present 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 elements; using the intermediate as an anode, performing anodization in an alkaline electrolyte to form a nickel-rich oxide layer, thereby obtaining the anode catalyst material.

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

[0009] According to an embodiment of yet another aspect of the present application, there is provided an application of the above-mentioned anode catalytic material as an anode in the field of electrolytic oxygen production.

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

[0011] According to an embodiment of yet another aspect of the present application, an electrolytic cell is provided, wherein the electrolytic cell comprises the anode catalytic material described in any one of the above items.

[0012] According to the anode catalytic material and its preparation method and application provided by the embodiment of the present application, first, an alloy containing nickel and iron elements is used as the substrate of the anode catalytic material, and a nickel-rich oxide layer can be coated on the surface of the substrate by an anodic oxidation method, so as to reduce the anode overpotential and thus reduce the energy consumption of water electrolysis. Secondly, by regulating the proportion of nickel and iron content in the alloy, the long-term stability of the nickel-rich oxide layer can be improved, and while maintaining a low overpotential, the dissolution of other elements (such as iron elements, etc.) in the substrate is significantly inhibited, the stability of the catalytic material is enhanced, and the purity of the obtained oxygen is improved. In particular, for high nickel-iron ratio alloys, it can be directly anodized to obtain the anode catalytic material, and it is suitable for preparing anode catalytic materials by in-situ anodization preparation method; and for low nickel-iron ratio alloys, a nickel-containing metal layer can be deposited on its surface, and after increasing the nickel content on the surface of the substrate layer, it can also be anodized to construct a long-term structurally stable nickel-rich oxide layer on the substrate surface. In addition, when an appropriate amount of molybdenum is contained in the alloy material, a trace amount of molybdenum will be dynamically deposited on the cathode side, improving the surface structure and electrocatalytic activity of the cathode, thereby improving the catalytic performance of the cathode and reducing the overall electrolysis energy consumption. The electrolytic cell of the present application has the same or similar advantages as the prior art and the aforementioned anode catalyst material, which will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The above and other objects, features and advantages of the present application will become more apparent through the following description of the embodiments of the present application with reference to the accompanying drawings, in which:

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

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

[0016] Figure 3This is a curve diagram of the change in cell voltage of the 904L anode obtained in Example 1 of the present application after working in the electrolytic cell cell 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 the present 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 the present application after working in the electrolytic cell chamber for 20 days;

[0019] Figure 6 This is a scanning electron microscope image of the cathode material surface of the electrolytic cell chamber containing the 904L anode obtained in Example 1 of the present application after operation for 20 days;

[0020] Figure 7 The cathode polarization curves of the electrolytic cell chamber in Example 1 of the present application before and after continuous operation for 20 days;

[0021] Figure 8 This is a curve diagram of the change in cell voltage of the pure nickel mesh anode of Comparative Example 1 of the present application after working in the electrolytic cell cell for 10 days;

[0022] Fig. 9 This is a curve diagram of the change in cell voltage of the 304 stainless steel in Comparative Example 2 of the present application after working in the electrolytic cell cell for 20 days;

[0023] Fig.10 This is a graph showing the change in hydrogen content in oxygen of the 304 stainless steel of Comparative Example 2 of the present application after working in the electrolytic cell chamber for 20 days;

[0024] Fig.11 This is a scanning electron microscope image of the surface of the anode and cathode materials of the electrolytic cell chamber of Comparative Example 2 of the present application after operation for 20 days;

[0025] Fig.12 This is the EDS spectrum of the anode surface of the 304 stainless steel of Comparative Example 2 of the present application after working in the electrolytic cell chamber for 20 days. DETAILED DESCRIPTION

[0026] In order to make the objectives, technical solutions and advantages of the present application more clearly understood, the present application is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0027] The terms used herein are only for describing specific embodiments and are not intended to limit the present application. The terms "including", "comprising", etc. 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 (including technical and scientific terms) used herein 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 as having a meaning consistent with the context of this specification and should not be interpreted in an idealized or overly rigid manner.

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

[0029] In the process of realizing the concept of this application, it was found that cheaper alloys containing nickel and iron elements, such as stainless steel, can be used as anode catalyst materials for alkaline water electrolysis, thereby reducing the oxygen evolution overpotential and improving the oxygen evolution efficiency. However, it was further found that as these materials are used for a longer time, the metal deposits in the cathode chamber of the electrolytic cell will gradually increase, affecting the performance of the electrolytic cell and even causing the risk of diaphragm puncture. Through experimental analysis, it is speculated that the reason is that the iron element in the alloy will be oxidized during the electrolysis process to form the intermediate product HFeO2 - , and it is easy to further react with alkaline solution to be converted into Fe2O3 or FeOOH, leaving the electrode surface and entering the electrolyte. In addition, the Fe element ions in the electrolyte are easy to deposit on the cathode surface during the electrolysis process, and even grow into a dendrite structure. The dendrite structure may grow and penetrate the diaphragm to reach the anode side, so that the anode side is also accompanied by the occurrence of hydrogen evolution reaction, which seriously affects the hydrogen content index in oxygen and causes major safety hazards.

[0030] In addition, it was further discovered that common elements in alloys such as chromium (Cr), manganese (Mn), molybdenum (Mo), and silicon (Si) would also migrate into the electrolyte in the form of ions. Chromium is easy to migrate into the electrolyte in the form of high-valent oxygen-containing ions (CrO4 2- or Cr2O7 2- ) exists in the electrolyte; manganese is initially present as MnO4 2- Molybdenum will also be partially dissolved in the form of MoO4 2- The continued dissolution of these elements will affect the stability of the substrate skeleton structure and the purity of the produced oxygen.

[0031] Therefore, the present invention coats a dense nickel-rich oxide layer on an alloy substrate containing nickel and iron elements, and the nickel-rich oxide layer contains nickel oxide and / or nickel hydroxide. First, a protective barrier is formed based on the nickel-rich oxide layer, which can effectively block the substrate and the electrolyte, and inhibit the further precipitation of metal ions from the substrate during the electrolysis process, thereby avoiding the risk of collapse of the alloy substrate skeleton structure due to continuous corrosion, and ensuring the original mechanical stability of the alloy substrate. Secondly, the nickel oxide and / or nickel hydroxide of the nickel-rich oxide layer, as well as a certain amount of nickel-iron hydroxide that may be further included, have efficient catalytic activity, provide abundant active sites for the electrolysis reaction, further promote the oxidation and decomposition of water molecules on the anode side, and improve the water decomposition efficiency.

[0032] Specifically, according to an embodiment of one aspect of the present application, an anode catalytic material is provided, comprising a substrate and a nickel-rich oxide layer, wherein: the substrate is an alloy comprising nickel and iron elements; the 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 element in the metal component of the nickel-rich oxide layer is greater than 70%.

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

[0034] According to the embodiments of the present application, "nickel oxide and / or nickel hydroxide" mainly refers to nickel oxide or oxyhydroxide, and according to the anode side reaction of metallic nickel, the valence state of nickel may include +2, +3, etc., and specifically may include one or more of NiO, Ni2O3, NiOOH, Ni(OH)2, etc.

[0035] According to the embodiments of the present application, first, the anode catalyst material uses an alloy of nickel and iron as the anode catalyst material substrate, and the addition of iron promotes proton conduction and charge transfer, 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, avoid the collapse of the alloy substrate skeleton structure, and maintain the original mechanical stability of the alloy substrate. Again, when the nickel-rich oxide layer is used as an anode, its thickness will not significantly increase after the formation is stable and affect its catalytic performance. In addition, the nickel oxide and / or nickel hydroxide contained in the nickel-rich oxide layer, and the nickel-iron hydroxide that can be further included are also used as active components in the catalytic reaction. By being closely combined with the substrate material, while ensuring that the substrate material can efficiently transmit electrons to the catalyst, the catalytic activity of the material is further guaranteed.

[0036] According to an embodiment of the present application, the mass ratio of the nickel element to the iron element of the substrate is 0.15~10, for example, the mass ratio of the nickel element to the iron element can be 0.15, 0.16, 0.45, 0.5, 1, 1.1, 1.35, 3, 4.2, 5, 7, 9, 10. The mass content of the nickel element is not less than 10%, for example, it can be 10%, 11%, 20%, 25%, 34%, 40%, 43%, 50%, 60%, 70%, 75%, 76%, 80%, 85%, 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 surface of the substrate by anodic oxidation. At the same time, the content of the nickel element in the substrate should not be too high. Excessive nickel content will cause the anode overpotential to be high, thereby reducing the oxygen evolution performance and affecting the overall electrolysis efficiency. Preferably, the mass content of the nickel element of the substrate is 10%~80%.

[0037] According to the embodiments of the present application, since a nickel-rich oxide layer is formed, a material with a nickel:iron element mass ratio within a wide range and a variable nickel content can be selected as a substrate. On the one hand, it can have a lower anode overpotential, thereby achieving lower energy consumption for water electrolysis. On the other hand, it can also better maintain structural stability to flexibly adapt to the needs of different applications.

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

[0039] According to the embodiments of the present application, elemental nickel or nickel-based alloy exists between the substrate with low nickel content 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 an embodiment of the present application, the mass ratio of nickel and iron elements in the substrate is 0.4~10. For example, the mass ratio of nickel and iron elements can be 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 element is 21%~80%. For example, it can be 21%, 25%, 30%, 34%, 43%, 60%, 70%, 75%, 76%, and 80%.

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

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

[0043] According to the embodiments of the present application, since the oxygen evolution activity of other elements (Cr, Mn, Mo, Si, etc.) in the substrate is relatively low, a high content thereof is not conducive to improving the efficiency of the oxygen evolution reaction. However, it is found that it is more preferred to include an appropriate amount of molybdenum. During the electrolysis of water, as the anode reaction proceeds, trace amounts of molybdenum will be converted into MoO4 2- The morphology is dissolved from the anode surface and dynamically deposited 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 an embodiment of the present application, the substrate may include nickel-containing stainless steel or a nickel-based alloy, the stainless steel being 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 being selected from 800 nickel-based alloy, 825 nickel-based alloy, 601 nickel-based alloy, or 600 nickel-based alloy.

[0045] According to an embodiment of the present application, the substrate may further include a customized synthetic material that meets the nickel content requirements, and a material corresponding to a metal material with a low nickel content that increases its surface nickel content by surface nickel enrichment, electrodeposition, chemical plating, etc. Further optionally, the substrate may be a material whose surface is plated with a nickel-containing metal layer (e.g., nickel elemental metal or nickel-iron alloy) on commercially available stainless steel or a nickel-based alloy, for example, a nickel-iron alloy is plated on the surface of 316L stainless steel. The nickel-iron alloy may be a nickel element to iron element mass ratio of 0.4 to 10, such as 0.4, 0.8, 2, 4, 5, 6, 8, 10, and a nickel element mass content of 21% to 80%, such as 21%, 25%, 30%, 34%, 43%, 60%, 70%, 75%, 76%, 80%.

[0046] According to the embodiments of the present application, the shape of the base material is not limited, for example, it can be a metal mesh, a metal plate, a plate mesh, etc. Stainless steel or a nickel-based alloy can be used. The material is cheap and easy to obtain, which effectively reduces the overall cost of the catalytic material and improves the economy and practicality.

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

[0048] According to the embodiments of the present application, a higher content of nickel in the nickel-rich oxide layer is conducive to the formation of a dense oxide layer, thereby reducing the dissolution effect of ions in the base 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 is not conducive to reducing the overpotential and will reduce the electronic conductivity. If the nickel content is too low, it is difficult to form a dense porous structure, which is not conducive to inhibiting the dissolution of metal ions.

[0049] According to another embodiment of the present application, a method for preparing the above-mentioned anode catalyst material is provided. Figure 1 Schematic diagram of the process for preparing the anode catalyst material of the present invention. Figure 1 As shown, the preparation method of the present application may include the following steps S101 to S102.

[0050] In step S101, 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 elements;

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

[0052] According to the embodiments of the present application, a nickel-containing metal layer is deposited on the substrate layer, the nickel content on the surface of the substrate layer is increased, and then a nickel-rich oxide layer is constructed on the substrate surface by anodic oxidation. The nickel-rich oxide layer can inhibit the dissolution of metal ions in the substrate layer, and the prepared anode catalyst material has a good oxygen evolution effect when used as an anode. In addition, after the nickel-rich oxide layer grows stably, the thickness will not increase significantly when used as an anode, thereby affecting its catalytic performance.

[0053] According to an embodiment of the present application, in step S101, depositing a nickel-containing metal layer on the surface of a 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 the present application, in step S101, the nickel-containing metal layer may be, for example, a material of a nickel single metal or a nickel-based alloy, and further, for example, may be a nickel-iron alloy plated on the surface of stainless steel or a nickel-based alloy. The nickel-iron alloy may have a mass ratio of nickel to iron of 0.4 to 10, such as 0.4, 0.45, 0.8, 1.1, 1.35, 2, 4, 4.2, 5, 6, 8, 9, 10.

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

[0056] According to an embodiment of the present application, further optionally, the nickel source in the electrolyte can be one or more of nickel nitrate, nickel sulfate, and nickel sulfide. In addition, the electrolyte can also contain other additives, such as boric acid, sodium chloride, sodium nitrate, sodium citrate, sodium acetate, sodium saccharin, etc.

[0057] According to the embodiments of the present application, further optionally, the amount of nickel-containing metal layer deposited on the substrate surface can be controlled by the total amount of electricity deposited according to the different nickel content of the substrate. Specifically, assuming that all non-nickel parts of the substrate material are replaced by nickel, the number of moles of nickel that can be deposited on the electrode surface is x = (1-mol content of nickel in the bulk) × electrode contactable area (cm 2 ) / Area of ​​nickel atom (6.5×10 -14 cm 2 ) / unit molar atomic weight (6.02×10 23 );

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

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

[0060] According to an embodiment of the present application, in step S102, the conditions for anodization include: in a 10%~50% (for example, it can be 10%, 20%, 25%, 30%, 35%, 40%, 50%) NaOH or KOH electrolyte, a temperature of 25~95°C (for example, it can be 25°C, 40°C, 50°C, 60°C, 70°C, 80°C, 95°C), applying a voltage of 1.5~3.5 V (for example, it can be 1.5 V, 1.8 V, 2.0 V, 2.2 V, 2.5 V, 3.0 V, 3.5 V), and continuing for 72~1440 hours (for example, it can be 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 the present application, preferably, the mass ratio of nickel element to iron element of the substrate is 0.4~10, and the mass content of nickel element is 21%~80%; at this time, the preparation method of the present application is to use the substrate as the anode and perform anodization in an alkaline electrolyte to obtain the anode catalyst material.

[0062] According to an embodiment of the present application, for the above substrate having a preferred composition of nickel and iron elements, the anodization in step S102 can be to directly use the substrate as an anode material in an industrial alkali tank, and a nickel-rich oxide layer can be formed in situ on the substrate in a period of time (e.g., 15 to 60 days). The anodization time can be determined according to the substrate material and application requirements, and as the nickel content in the substrate material increases, the anodization time can be appropriately increased to form a more stable nickel-rich oxide layer.

[0063] According to an embodiment of yet another aspect of the present application, there is provided an application of the above-mentioned anode catalytic material as an anode in the field of electrolytic oxygen production.

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

[0065] According to another embodiment of the present application, there is provided an application of stainless steel or nickel-based alloy in the preparation of an anode catalytic material, wherein the mass ratio of nickel element to iron element in the stainless steel or nickel-based alloy is 0.4-10 (for example, it may be 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 element is 21%-80% (for example, it may be 21%, 25%, 30%, 34%, 43%, 60%, 70%, 75%, 76%, 80%).

[0066] According to the embodiments of the present application, the above-mentioned stainless steel or nickel-based alloy can be used to prepare anode catalyst materials, which can be conducive to forming a stabilized nickel-rich oxide layer on the surface. On the one hand, the nickel-rich oxide layer can passivate the substrate, inhibit the precipitation of metal ions in the substrate, avoid the collapse of the alloy substrate skeleton structure, and maintain the original mechanical stability of the alloy substrate. On the other hand, the nickel oxide and / or nickel hydroxide contained in the nickel-rich oxide layer, as well as the nickel-iron hydroxide that may be further contained, can be used as active components in the catalytic reaction, and through close combination with the substrate material, while ensuring that the substrate material can efficiently transfer electrons to the catalyst, the catalytic activity of the material is further guaranteed.

[0067] According to an embodiment of the present application, the stainless steel or nickel-based alloy can 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 mass ratio of nickel to iron ≥ 0.4 and a mass content of nickel ≥ 21%.

[0068] According to the embodiments of the present application, the anode catalyst material prepared from the above stainless steel or nickel-based alloy can be used in the reaction of electrolyzing alkaline water to produce oxygen. This is conducive to improving the reaction activity and stability of electrolyzing water to produce oxygen, and is conducive to reducing the energy consumption of electrolyzing water to produce oxygen, and has the advantage of low cost.

[0069] According to an embodiment of the present application, the method for preparing the anode catalyst material is an in-situ anodization preparation method. The "in-situ" here means that in the reaction system, the stainless steel or nickel-based alloy can first undergo an anodization reaction to generate an anode catalyst material, and then be used as an anode catalyst material in the system, without the need to first prepare the anode catalyst material in one reaction system and then transfer it to another reaction system for use as an anode catalyst. It may be further preferred that the stainless steel or nickel-based alloy is anodized in a device for producing oxygen by electrolysis with an alkaline electrolyte, wherein the device for producing oxygen by electrolysis with an alkaline electrolyte may be 100-5000 Nm 3 / h industrial bipolar electrolyzer, 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 the present application, an electrolytic cell is provided, which includes the anode catalytic material described in any one of the above items. The electrolytic cell can be a device for producing oxygen by electrolysis of alkaline electrolyte, such as an alkaline water oxygen electrolytic cell (ALK) or the like.

[0071] The present invention is further described below by embodiments and related test experiments. In the following detailed description, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of the embodiments of the present invention. However, it is obvious that one or more embodiments may also be implemented without these specific details. And, in the absence of conflict, the details in the following embodiments may be combined into other feasible embodiments at will.

[0072] Embodiment 1:

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

[0074] The above-mentioned stainless steel 904L metal mesh was placed in the electrolytic cell, and the counter electrode was 5×5 cm 2 The size of the pure nickel mesh is 250 μm in diameter and the mesh size is 50. A 30% KOH solution is used as the electrolyte, and a pps fabric is used as the diaphragm. It is operated continuously for 30 days at normal pressure, 85°C, and a voltage of 2.3V, and then taken out for washing and drying to obtain a 904L anode. In this process, the nickel-rich oxide layer on the surface of the 904L anode is gradually formed and stabilized.

[0075] The 904L anode with a nickel-rich oxide layer on the surface, the new pure nickel mesh cathode and the diaphragm were reassembled in the electrolytic cell chamber to perform the water electrolysis oxygen production reaction at an operating temperature of 85°C, an operating pressure of atmospheric pressure, and an operating current density of 3000 A / m 2 .

[0076] Figure 2 This is a cross-sectional view of the 904L anode obtained in Example 1 of the present application. The gray box area of ​​the nickel-rich layer was subjected to element scanning analysis by an energy dispersive spectrometer (EDS), and the nickel-iron ratio was 2.9, and the proportion of Ni in the metal elements (Ni, Fe, Cr, Mn, Mo) was 71%. Figure 2 The thickness of the nickel-rich layer shown is approximately 1 μm.

[0077] Figure 3This is a curve of the change in chamber voltage of the 904L anode containing a nickel-rich oxide layer obtained in Example 1 of the present application, which has been working in the electrolytic cell chamber for 20 days.

[0078] like Figure 3 As shown in the figure, during the 20-day continuous operation period of the electrolytic cell chamber, the change trend of the chamber voltage showed good stability, basically maintained at around 2.14 V, and no significant upward or downward trend appeared, which proved that the anode material used can ensure that the electrolytic cell can continue to 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 after the 904L anode obtained in Example 1 of the present application has worked in an electrolytic cell chamber for 15 days.

[0080] like Figure 4 As shown, during the 15 days of continuous operation in the electrolytic cell chamber, the hydrogen content in oxygen remained at a low level, basically maintained 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 image of the 904L anode obtained in Example 1 of the present application after working in the electrolytic cell chamber for 20 days; 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 the thickness was still about 1 μm.

[0082] Figure 6 This is a scanning electron microscope image of the cathode material surface of the electrolytic cell chamber containing the 904L anode obtained in Example 1 of the present application after operation for 20 days, wherein (a) is a scanning electron microscope image of the cathode surface, and (b) is a partial enlarged image of (a).

[0083] like Figure 6 As shown, after the electrolytic cell chamber has been running continuously for 20 days, there is no obvious change on the corresponding cathode surface, indicating that there is no obvious dissolution and redeposition of metal. Elemental analysis of the cathode surface by energy spectrometer revealed that the cathode surface contained 0.24% molybdenum by mass, that is, the trace molybdenum element dissolved from the anode surface was dynamically deposited on the cathode side.

[0084] In addition, polarization curves were tested on the cathode of the electrolytic cell before and after continuous operation for 20 days. The test conditions were as follows: room temperature, 1 mol / L KOH, three-electrode system, working electrode as the corresponding cathode, effective area 1×1 cm 2 , the counter electrode is pure nickel mesh, and the reference electrode mesh is Hg / HgO electrode. Figure 7As shown, when achieving the same current density, the overpotential required for the cathode is reduced after the electrolytic cell chamber has been running continuously for 20 days, indicating that the deposition of molybdenum can improve the surface structure and electrocatalytic activity of the cathode and enhance the hydrogen evolution performance of the cathode, that is, accelerate the hydrogen evolution rate and efficiency, thereby reducing the overall energy consumption of water electrolysis.

[0085] Embodiment 2:

[0086] In the application of industrial alkaline electrolysis cell oxygen production, 904L stainless steel material with a mass ratio of nickel to iron of about 0.45, a mass content of nickel of about 25%, and a mass content of molybdenum of about 4% is selected as the anode substrate material, with a structure of 5×5 cm 2 The size of the plain mesh is woven with a wire diameter of 160 μm and a mesh number of 60.

[0087] The above stainless steel 904L metal mesh was placed in a double-electrode electrolytic cell for anodization. The counter electrode was 5×5 cm 2 The size of the pure nickel mesh is woven with a wire diameter of 250 μm and a mesh size of 50. A 35% concentration of KOH solution was selected as the electrolyte, the temperature was controlled at 90°C, the voltage was cycled between 2V and 2.5V at a rate of 0.5V / s, and it was continuously operated for 480 h. After stopping, the electrode was taken out, rinsed with deionized water, and dried to obtain the required 904L anode. The cross-section of the 904L anode was photographed by scanning electron microscopy. The thickness of the nickel-rich oxide layer on the surface was 1.2-1.5 μm, the nickel-iron ratio was 3, and the nickel content in the metal component was about 74%.

[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 heated at 3000 A / m 2 The current density was 2.5, and the temperature of the chamber was controlled at 85°C. During the 60-day test, the chamber voltage was basically stable at 2.09 V, and the hydrogen content in oxygen was kept stable below 0.1%. There was no obvious change in the cathode and anode surfaces after 60 days of reaction. The elemental analysis of the cathode surface by energy spectrometer found that the cathode surface contained 0.31% molybdenum by mass. In addition, the polarization curve test was conducted on the cathode before and after the electrolytic cell chamber was continuously operated for 60 days. The results showed that the overpotential required for the cathode was reduced after the electrolytic cell chamber was continuously operated for 60 days.

[0089] Embodiment 3:

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

[0091] The nickel-based alloy 800 metal mesh was placed in a double-electrode electrolytic cell for anodization. The counter electrode was 5×5 cm 2 The size of the pure nickel mesh was woven with a wire diameter of 250 μm and the mesh size was set to 50 mesh. A 35% concentration of KOH solution was selected as the electrolyte, the temperature was controlled at 90°C, the voltage was cycled between 2V and 2.5V at a rate of 0.5V / s, and it was continuously operated for 720 h. After stopping, the electrode was taken out, rinsed with deionized water, and dried to obtain the required 800 anode. The cross-section of the anode was photographed by scanning electron microscopy. The thickness of the nickel-rich oxide layer on the surface was about 1.1 μm, the nickel-iron ratio was 3.1, and the nickel content in the metal component was about 77%.

[0092] The obtained 800 anode with a nickel-rich oxide layer was placed in an electrolytic cell chamber containing a Zirfon 500UPT diaphragm and a cathode of 5×5 cm 2 The pure nickel mesh is 250 μm in diameter and 50 mesh in size. 2 The current density was 2.50 and the temperature of the chamber was controlled at 85°C. The chamber voltage was stable at 2.15 V within 60 days, and the hydrogen content in oxygen was kept stable below 0.1%. There was no obvious change on the cathode and anode surfaces after 60 days of reaction.

[0093] Embodiment 4:

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

[0095] The nickel-based alloy 825 metal mesh was placed in a double-electrode electrolytic cell for anodization. The counter electrode was 5×5 cm 2 The size of the pure nickel mesh was woven with a wire diameter of 250 μm and the mesh size was set to 50 meshes. A 35% concentration of KOH solution was selected as the electrolyte, the temperature was controlled at 90°C, and the voltage was continuously operated at 2.5V for 600 h. After stopping, the electrode was taken out, rinsed with deionized water, and dried to obtain the required 825 anode. The cross-section of the anode was photographed by scanning electron microscopy. The thickness of the nickel-rich oxide layer on the surface was about 0.9 μm, the nickel-iron ratio was 3.3, and the nickel content in the metal component was about 76%.

[0096] The obtained 825 anode with a nickel-rich oxide layer was placed in an electrolysis chamber containing a Zirfon 500UPT diaphragm and a cathode of 5×5 cm 2The pure nickel mesh is 250 μm in diameter and 50 mesh. 2 The current density was 2.04 and the temperature of the chamber was controlled at 90°C. After 60 days, the measured chamber voltage was stable at 2.17 V, and the hydrogen content in oxygen was kept stable below 0.1%. There was no obvious change in the cathode and anode surfaces after 60 days of reaction. The elemental analysis of the cathode surface by energy spectrometer found that the cathode surface contained 0.29% molybdenum by mass. In addition, the polarization curves of the cathodes before and after the electrolytic cell chamber was continuously operated for 60 days were tested. The results showed that the overpotential required for the cathode decreased after the electrolytic cell chamber was continuously operated for 60 days.

[0097] Embodiment 5:

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

[0099] The nickel-based alloy 600 metal mesh was placed in a double-electrode electrolytic cell for anodization. The counter electrode was 5×5 cm 2 The size of the pure nickel mesh is 250 μm in diameter and 50 mesh. A 30% concentration of KOH solution was selected as the electrolyte, the temperature was controlled at 90°C, and the voltage was continuously operated at 2.8V for 300 h. After stopping, the electrode was taken out, rinsed with deionized water, and dried to obtain the required 600 anode. The cross section of the anode was photographed by scanning electron microscopy. The thickness of the nickel-rich oxide layer on the surface was about 0.6 μm, the nickel-iron ratio was 5.1, and the nickel content in the metal component was about 83%.

[0100] The obtained 600 anode with a nickel-rich oxide layer was placed in an electrolytic cell chamber containing a Zirfon 500UPT diaphragm and a cathode of 5×5 cm 2 The pure nickel mesh is 250 μm in diameter and 50 mesh. 2 The current density was 2.04 and the temperature of the chamber was controlled at 90°C. The chamber voltage was stable at 2.18 V and the hydrogen content in oxygen was kept below 0.1% within 60 days. There was no obvious change on the cathode and anode surfaces after 60 days of reaction.

[0101] Embodiment 6:

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

[0103] The nickel-based alloy 601 metal mesh was placed in a double-electrode electrolytic cell for anodization. The counter electrode was 5×5 cm 2 The size of the pure nickel mesh is 250 μm in diameter and 50 mesh. A 30% concentration of KOH solution is selected as the electrolyte, the temperature is controlled at 90 ° C, and the voltage is 3.0V for continuous operation for 300 h. After stopping, the electrode is taken out, rinsed with deionized water, and dried to obtain the required 601 anode. The cross-section of the anode is photographed by scanning electron microscopy. The thickness of the nickel-rich oxide layer on the surface is about 0.5 μm, the nickel-iron ratio is 10, and the nickel content in the metal component is about 89%.

[0104] The obtained 601 anode with a nickel-rich oxide layer was placed in an electrolytic cell chamber containing a Zirfon 500UPT diaphragm and a cathode of 5×5 cm 2 The pure nickel mesh is 250 μm in diameter and 50 mesh. 2 The current density was 2.04 and the temperature of the chamber was controlled at 90°C. The voltage of the chamber was stable at 2.17 V and the hydrogen content in oxygen was kept below 0.1% within 60 days. There was no obvious change on the cathode and anode surfaces after 60 days of reaction.

[0105] Embodiment 7:

[0106] A 316L stainless steel wire mesh with a nickel-iron alloy coating of 100 μm with a mass ratio of nickel and iron of about 5 and a nickel content of about 80% was selected. The overall size specification is: 5×5 cm 2 The size of the plain mesh is 250 μm in diameter and 40 mesh.

[0107] The stainless steel 316L metal mesh coated with nickel-iron alloy was placed in a double-electrode electrolytic cell for anodization. 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% concentration of KOH solution was selected as the electrolyte, the temperature was controlled at 90°C, the voltage was cycled at a rate of 1V / s between 1.9-2.6V, and it was continuously operated for 360 h. After stopping, the electrode was taken out, rinsed with deionized water, and dried to obtain the required 316L anode. The cross-section of the anode was photographed by scanning electron microscopy. The thickness of the nickel-rich oxide layer on the surface was about 1.2 μm. The nickel-iron ratio was 6 according to EDS elemental analysis, and the nickel content in the metal component was about 83%.

[0108] The obtained anode containing a nickel-rich oxide layer and a new pure nickel mesh cathode were placed in an electrolysis chamber containing a Zirfon 500UPT diaphragm and heated at 3000 A / m. 2The current density was set at 85°C, and the cell temperature was kept at 85°C. The cell voltage was kept stable at 2.16V within 60 days, and the hydrogen content in oxygen was kept stable below 0.1%. There was no obvious change on the cathode and anode surfaces after 60 days of reaction.

[0109] Example 8

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

[0111] The above 314 stainless steel mesh was placed in a double-electrode electrolytic cell for anodization. The counter electrode was 5×5 cm 2 The size of the pure nickel mesh is 250 μm in diameter and 50 mesh. A 30% concentration of KOH solution was selected as the electrolyte, the temperature was controlled at 90 ° C, and the voltage was 2.5V for continuous operation for 640 h. After stopping, the electrode was taken out, rinsed with deionized water, and dried to obtain the required 314 anode with a surface nickel-rich layer. The cross-section of the anode was photographed by scanning electron microscopy. The thickness of the surface nickel-rich oxide layer was about 1.3 μm, the nickel-iron ratio was 2.85, and the nickel content in the metal component was about 72%.

[0112] The obtained 314 anode with a nickel-rich oxide layer was placed in an electrolytic cell chamber containing a Zirfon 500UPT diaphragm and a cathode of 5×5 cm 2 The pure nickel mesh is 250 μm in diameter and 50 mesh. 2 The current density was 2.04 and the temperature of the chamber was controlled at 90°C. The voltage of the chamber was basically stable at 2.14 V within 60 days, and the hydrogen content in oxygen was kept stable below 0.1%. There was no obvious change on the cathode and anode surfaces after 60 days of reaction.

[0113] Example 9

[0114] In the application of industrial alkaline electrolyzer oxygen production, 316L stainless steel material with a mass ratio of nickel and iron of about 0.16, a mass content of nickel of about 11%, and a mass content of molybdenum of about 1.4% is selected as the base material, with a specification of 5×5 cm 2 The size of the steel wire mesh is 250 μm in diameter and 40 meshes.

[0115] After cleaning the substrate material with acetone and ethanol, soak it in 1M sulfuric acid for 2 hours, rinse it with deionized water, and dry it at room temperature;

[0116] Then, the substrate material is 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 is controlled at 0.003 coulombs, the current is set to 0.6 mA, and the deposition time is set to 5 s to obtain the deposited intermediate material.

[0117] The intermediate material was used as the anode and the nickel wire mesh of the same size was used as the cathode. The anode was placed in a 6M KOH electrolyte, the chamber potential was set to 2V, and the operating temperature was controlled at 85°C for anodic oxidation. After running for 480 hours, the anode was taken out, rinsed with deionized water, and dried at room temperature to obtain a 316L anode.

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

[0119] The prepared 316L anode and a new pure nickel mesh cathode were placed in an electrolytic cell chamber containing a Zirfon 500UPT diaphragm. The cathode was 5×5 cm 2 The pure nickel mesh with a wire diameter of 250 μm and a mesh size of 50 was used. It was operated at a current density of 3000 A / m² and the temperature of the chamber was controlled at 85°C. After 20 days, the measured chamber voltage was stable at 2.15 V, and the hydrogen content in oxygen was stably maintained below 0.1%. After 20 days of reaction, the cathode and anode surfaces remained flat and crack-free. The elemental analysis of the cathode surface by energy spectrometer found that the cathode surface contained 0.1% molybdenum by mass. In addition, the polarization curve test was performed on the cathode before and after the electrolytic cell chamber was continuously operated for 20 days. The results showed that the overpotential required for the cathode was reduced after the electrolytic cell chamber was continuously operated for 20 days.

[0120] Example 10

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

[0122] The substrate material was cleaned with ethanol and acetone, immersed in 1M sulfuric acid for 1 hour, rinsed with deionized water, and dried at room temperature;

[0123] Then, the substrate material is 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 is controlled at 0.002 coulomb, the current is set to 0.4 mA, and the deposition time is set to 5 s to obtain the deposited intermediate material.

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

[0125] The obtained 310s anode was observed by scanning electron microscopy (SEM) and elemental analysis was performed by energy dispersive spectrometer. The thickness of the nickel-rich oxide layer on the surface was about 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 could be found between the surface oxide layer and the base layer.

[0126] The target 310s anode prepared above and a new pure nickel mesh cathode were placed in an electrolytic cell chamber containing a Zirfon 500UPT diaphragm. The cathode was 5×5 cm 2 The pure nickel mesh is woven with a wire diameter of 250 μm and a mesh size of 50. It is operated at a current density of 3000A / m² and the temperature of the chamber is controlled at 85°C. After 30 days, the voltage of the chamber is basically stable at 2.16 V, the hydrogen content in oxygen is stably maintained below 0.1%, and the cathode and anode surfaces remain flat without cracks after 20 days of reaction.

[0127] Comparative Example 1:

[0128] In the application of industrial alkaline electrolytic cell oxygen production, pure nickel mesh is selected as the anode of industrial alkaline electrolytic cell, with a structure of 5×5 cm 2 The size of the plain mesh is 250 μm in diameter and the mesh size is 50. The cathode is 5×5 cm 2 The pure nickel mesh is woven with a wire diameter of 250 μm and the mesh number is set to 50 mesh.

[0129] The pure nickel mesh anode and cathode were placed in an electrolytic cell chamber containing a Zirfon 500UPT diaphragm at 3000 A / m 2 The current density was maintained at 85 °C for 10 days.

[0130] Figure 8 This is a curve diagram of the change in cell voltage of the pure nickel mesh anode in the electrolytic cell chamber of comparative example 1 of the present application after working in the chamber for 10 days.

[0131] like Figure 8 As shown in the figure, during the 10-day continuous operation cycle of the electrolytic cell chamber, the chamber voltage experienced a power outage on the 5th day. After 10 days, the chamber voltage basically remained at around 2.3 V, without showing a significant upward or downward trend. This comparative example shows that when pure nickel mesh is used as the anode material, the chamber potential is higher and the energy consumption for electrolytic oxygen production is higher.

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

[0133] Comparative Example 2:

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

[0135] The stainless steel 304 metal mesh and cathode were placed in the electrolytic cell chamber containing the Zirfon 500UPT diaphragm and the electrolysis was carried out at 3000A / m 2 The current density was maintained at 85°C for 20 days.

[0136] Fig. 9 This is a curve diagram of the change in chamber voltage of the stainless steel 304 in comparative example 2 of the present application after working in the electrolytic cell chamber for 20 days.

[0137] like Fig. 9 As shown in the figure, during the 20-day continuous operation of the electrolytic cell, the cell voltage fluctuated significantly, and the electric density began to decrease from the 10th day. After 20 days, the cell voltage was basically maintained at around 1.9 V.

[0138] Fig.10 This is a graph showing the change in hydrogen content in oxygen of stainless steel 304 of comparative example 2 of the present application after working in an electrolytic cell chamber for 20 days.

[0139] like Fig.10 As shown, the hydrogen content in oxygen in the electrolytic cell chamber showed a gradual increasing trend during 20 days of continuous operation. It began to increase significantly after the 7th day. On the 14th day, the hydrogen content in oxygen increased to 24%. The lower explosion limit of hydrogen in oxygen was 4%, posing a major safety hazard.

[0140] Fig.11These are scanning electron microscope images of the surfaces of the anode and cathode materials of the electrolytic cell chamber of Comparative Example 2 of the present application after 20 days of operation, wherein (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 partial enlarged image of (b).

[0141] like Fig.11 As shown, after the electrolytic cell chamber has been in continuous operation for 20 days, the oxide layer on the anode surface has obvious cracks, and obvious metal deposition also appears on the corresponding cathode surface.

[0142] Fig.12 This is the EDS spectrum of the anode surface of stainless steel 304 in comparative example 2 of the present application after working in the electrolytic cell chamber for 20 days;

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

[0144] Comparative Example 3

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

[0146] The stainless steel 316L anode and cathode were placed in an electrolytic cell chamber containing a Zirfon 500UPT diaphragm and heated to 3000 A / m. 2 The current density was maintained at 85°C for 20 days.

[0147] After 20 days of continuous operation of the electrolytic cell chamber, the chamber voltage was basically maintained at about 2.08 V, and the hydrogen content in oxygen was basically maintained below 0.1%, but there was an increasing trend, and the oxide layer on the surface of the anode showed obvious cracking, and metal deposition also appeared on the corresponding cathode surface. EDS analysis showed that the nickel-iron ratio of the surface elements of the anode in Comparative Example 3 after 20 days of operation was about 1.5.

[0148] Comparative Example 4

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

[0150] The 310s stainless steel mesh was directly used as the anode, and the 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°C, and the electrode was set at 2.6 V for anodic oxidation. After running for 640 hours, it was taken out, rinsed with deionized water, and dried at room temperature to obtain the target 310s anode.

[0151] The obtained 310s anode was observed by scanning electron microscope (SEM) and elemental analysis was performed by energy dispersive spectrometer. It was found that a certain nickel-rich layer was formed on the surface, but the distribution was uneven and there were some gaps. EDS analysis showed that the mass ratio of nickel to iron in the nickel-rich layer area was about 2.5, and nickel accounted for 66% of the metal elements.

[0152] The target 310s anode prepared above and a new pure nickel mesh cathode were placed in an electrolytic cell chamber containing a Zirfon 500UPT diaphragm. The cathode was 5×5 cm 2 The pure nickel mesh is woven with a wire diameter of 250 μm and a mesh size of 50. It is operated at a current density of 3000A / m² and the temperature of the chamber is controlled at 85°C. The chamber voltage reaches 2.18 V after 30 days of measurement, and there is a continuous growth trend. The hydrogen content in oxygen is basically maintained below 0.1%, and there is also an increasing trend. After the reaction, a small amount of sediment can be observed on the cathode surface, and the oxide layer on the anode surface is 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, relative to the anode made of pure nickel base material, the anode catalytic material provided by the embodiments of the present invention can not only always maintain the hydrogen content in oxygen at a low level (<0.1%), and the anode surface morphology remains stable during long-term operation, but also can reduce the anode overpotential, thereby reducing the energy consumption of water electrolysis.

[0155] Secondly, it can be seen from Examples 1-8 that for stainless steel or nickel-based alloys with a high nickel content (Ni / Fe mass ratio of 0.4-10, nickel mass content of 21%-80%), they can be directly anodized in an alkaline electrolyte to obtain an anode catalyst material. It can be seen that it is suitable for preparing an anode catalyst material by an in-situ anodization preparation method, that is, stainless steel or nickel-based alloys can first be anodized in a reaction system to generate an anode catalyst material, and then used as an anode catalyst material in the system, without first preparing the anode catalyst material in a reaction system and then transferring it to another reaction system for use as an anode catalyst.

[0156] By comparing Examples 9-10 with Comparative Examples 3-4, it can be seen that for stainless steel with a high iron content (Ni / Fe mass ratio of 0.15 or more and less than 0.4, and the mass content of nickel element of 10% to 21%), when it is directly used as an anode catalyst material, although a lower anode overpotential (1.9V) can be achieved, the hydrogen content in oxygen reaches the explosion limit (24%) in long-term operation, which is prone to safety hazards. Moreover, after a long period of anodic oxidation, the anode surface cracks, and it is difficult to form a stable nickel-rich oxide layer, thereby reducing the electrolysis efficiency. However, when a nickel-containing metal layer is deposited on its surface to increase the nickel content on the surface of the substrate layer, a long-term structurally stable nickel-rich oxide layer can be constructed on the substrate surface through anodic oxidation.

[0157] Finally, it can be seen from the data of Examples 1-2, 4, and 9 that when the base material contains an appropriate amount of molybdenum, trace amounts of molybdenum will be dynamically deposited 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 solutions and beneficial effects of the present application. It should be understood that the above description is only a specific embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application should be included in the scope of protection of the present application.

[0159] Table 1

[0160]

Claims

1. An anode catalyst material, comprising: The substrate is an alloy containing nickel and iron elements; 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 element in the metal component of the nickel-rich oxide layer is greater than 70%.

2. The anode catalytic 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 element to iron element of the substrate is 0.15-10, and the mass content of nickel element is not less than 10%, preferably 10%-80%.

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

5. The anode catalyst material according to claim 1 or 4, wherein: There is single-element nickel or nickel-based alloy between the substrate and the nickel-rich oxide layer.

6. The anode catalyst material according to claim 1 or 2, wherein: The mass ratio of nickel element to iron element of the substrate is 0.4-10; the mass content of nickel element is 21%-80%.

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

8. A method for preparing an anode catalyst material, 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 elements; The intermediate is used as an anode and 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 depositing of the nickel-containing metal layer on the surface of the substrate comprises: using the substrate as a cathode and performing electrodeposition in an electrolyte containing a nickel source; and / or The anodizing conditions include: in a 10% to 50% NaOH or KOH electrolyte, a temperature of 25 to 95° C., applying a voltage of 1.5 to 3.5 V, and continuing for 72 to 1440 hours.

10. The preparation method according to claim 8 or 9, wherein: The mass ratio of nickel to iron in the substrate is 0.15-10, and the mass content of nickel is 10%-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%-21%; Alternatively, there is single nickel or nickel-based alloy between the substrate and the nickel-rich oxide layer.

11. A method for preparing an anode catalyst material, comprising: Provided is a substrate, wherein the mass ratio of nickel element to iron element of the substrate is 0.4-10, and the mass content of nickel element is 21%-80%; The substrate is used as an anode and anodic oxidation is performed in an alkaline electrolyte to obtain the anode catalytic material.

12. Use of the anode catalytic material according to any one of claims 1 to 7 as an anode in the field of electrolytic oxygen production.

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

14. The use according to claim 13, wherein: The anode catalytic material is used in the reaction of producing oxygen by electrolysis of alkaline water.

15. The use according to claim 13, wherein: The anode catalytic material is prepared by an in-situ anodizing method of the stainless steel or nickel-based alloy. Preferably, the stainless steel or nickel-based alloy is anodized in a device for producing oxygen by electrolysis with an alkaline electrolyte.

16. An electrolytic cell, characterized in that: The electrolytic cell comprises the anode catalytic material according to any one of claims 1 to 7.

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