Metal hydroxide, preparation method, electrolytic tank and application of metal hydroxide in seawater electrolytic hydrogen production

Abstract

The invention provides a metal hydroxide (LDH) and a preparation method and application thereof in seawater electrolysis, and belongs to the field of new materials and hydrogen energy preparation. Aqueous solutions of ferric salt, cobalt salt and nickel salt are stirred to obtain a mixed solution; under a constant voltage, metal ions of the mixed solution are subjected to a reduction reaction on the surface of the working electrode to generate ternary NiCoFe-LDH, namely, the metal hydroxide is obtained; according to the method, a high-activity and high-stability nano-structure material directly grows on a conductive substrate through an electrochemical deposition method of three metal (Fe, Co and Ni) hydroxides in a specific proportion, and the low-cost seawater electrolysis catalyst can be constructed only through direct in-situ growth of LDH through a potentiostatic method, so that the high-temperature and high-pressure requirements of a traditional hydrothermal method are avoided, and the method is suitable for industrial production. The LDH nanosheet array structure directly grown in the invention avoids the use of a binder, improves the mechanical stability of the electrode and prolongs the cycle life of the electrode. The ternary NiCoFe-LDH is used as an anode material of an electrolytic tank and can be used for directly electrolyzing seawater to produce hydrogen.

Description

Technical Field

[0001] The present application relates to the technical field of new material preparation and hydrogen energy production, and in particular to a metal hydroxide, a preparation method, an anode material and applications thereof. Background Art

[0002] Since the advent of industrial civilization, human society has become highly dependent on fossil fuels, resulting in significant carbon emissions, energy consumption, and ecological and environmental problems, leading to global climate change and unsustainable development. Efforts have been made to utilize renewable energy sources such as solar, wind, and hydropower to replace traditional fossil fuels such as coal, oil, and natural gas. However, renewable energy sources suffer from intermittent and unstable nature, as well as difficulty in large-scale storage, limiting their practical application. Hydrogen combustion produces water, which emits no carbon or pollutants, making it the world's cleanest energy source. Effectively coupling water electrolysis with renewable energy has the potential to become a strategic technology for large-scale hydrogen production and effective response to carbon emissions. Electrochemical water splitting is the most efficient method for producing green hydrogen to date. Water electrolysis involves two half-reactions: the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER). However, the OER is a kinetically slow four-electron transfer process that requires a significant energy barrier, necessitating the use of efficient OER catalysts to improve the overall efficiency of water splitting.

[0003] Currently, most water-splitting catalysts are first prepared as powders and then dispersed on a substrate using Nafion as a binder to form electrodes. This can lead to particle agglomeration and structural disorder. Furthermore, most catalyst designs are based on precious metals, significantly increasing the cost of industrial applications. Furthermore, existing catalysts generally suffer from poor stability and high reaction overpotentials in the complex electrolyte system of seawater, severely limiting their application in emerging fields such as marine energy. Summary of the Invention

[0004] In view of this, it is necessary to provide a metal hydroxide (LDH) self-supported catalytic material with a clear structure and excellent catalytic performance, a preparation method, an electrolytic cell and its application in seawater electrolysis for hydrogen production to address the defects of the existing technology.

[0005] To solve the above problems, this application adopts the following technical solutions:

[0006] One of the purposes of this application is to provide a method for preparing a metal hydroxide, comprising the following steps:

[0007] stirring aqueous solutions of iron salt, cobalt salt and nickel salt to obtain a mixed solution;

[0008] Under a constant voltage, the metal ions in the mixed solution undergo a reduction reaction on the surface of the working electrode to generate ternary NiCoFe-LDH, that is, the metal hydroxide.

[0009] In some embodiments, in the step of stirring the aqueous solutions of iron salt, cobalt salt and nickel salt to obtain a mixed solution, the molar ratio of iron ion, cobalt ion and nickel ion is (0.5-1.5):(1.5-2.5):(2-4).

[0010] In some embodiments, the mixed solution is a mixed solution of nitrates or sulfates.

[0011] In some embodiments, the total concentration of metal ions in the mixed solution is 0.04-0.07 mol / L, and the metal molar ratio is (0.5-1.5):(1.5-2.5):(2-4).

[0012] In some embodiments, under a constant voltage, the metal ions in the mixed solution undergo a reduction reaction on the surface of the working electrode to generate ternary NiCoFe-LDH, that is, to obtain the metal hydroxide, specifically comprising the following steps:

[0013] The pretreated metal substrate is used as the working electrode, the carbon rod is used as the counter electrode, the saturated calomel electrode is used as the reference electrode, the mixed solution is used as the electrolyte, a constant voltage is applied to deposit the metal ions in the mixed solution on the surface of the substrate, and then the surface of the working electrode is rinsed to obtain the metal hydroxide.

[0014] In some embodiments, the constant voltage is -1.8V to -2.2V relative to the electrode potential of a saturated calomel electrode, and the pressure is applied for 15 to 25 minutes.

[0015] In some embodiments, the step of pre-treating the metal substrate specifically includes: ultrasonically cleaning the metal substrate with acetone and dilute hydrochloric acid for 10 to 15 minutes respectively, and then washing with water to obtain a clean metal substrate.

[0016] In some embodiments, the metal substrate is one of foamed copper, foamed cobalt, and foamed nickel.

[0017] The second purpose of this application is to provide a metal hydroxide prepared by any of the preparation methods described above.

[0018] The third object of the present application is to provide an electrolytic cell comprising an anode material, wherein the anode material comprises the metal hydroxide.

[0019] A fourth object of this application is to provide the application of the electrolytic cell in seawater electrolysis.

[0020] This application adopts the above technical solution, and its beneficial effects are as follows:

[0021] The preparation method of the metal hydroxide provided in the present application comprises stirring an aqueous solution of an iron salt, a cobalt salt and a nickel salt to obtain a mixed solution; under a constant voltage, the metal ions in the mixed solution undergo a reduction reaction on the surface of a working electrode to generate a ternary NiCoFe-LDH, namely the metal hydroxide. The present application directly grows a highly active and highly stable nanostructured material on a conductive substrate through an electrochemical deposition method of a trimetallic (Fe, Co, Ni) hydroxide with a specific ratio. Since the LDH is directly grown in situ only by a constant potential method, a low-cost seawater electrolysis catalyst can be constructed, avoiding the high temperature and high pressure requirements of the traditional hydrothermal method. The directly grown LDH nanosheet array structure of the present application avoids the use of a binder, thereby improving the mechanical stability and cycle life of the electrode. The metal hydroxide provided in the present application can be used as an anode material for an electrolytic cell and can be applied in industrial scenarios of hydrogen production from seawater. It exhibits excellent catalytic activity and stability in seawater electrolysis, effectively improving the catalyst activity. In addition, the preparation method of the metal hydroxide provided in the present application can effectively reduce the cost of catalyst preparation, is expected to be realized in industrial application, and has great economic value. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments of the present application or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0023] Figure 1 is a scanning electron microscope (SEM) image of the NiCoFe-LDH obtained in Example 1;

[0024] Figure 2 TEM image of NiCoFe-LDH obtained in Example 1;

[0025] Figure 3 is the X-ray diffraction (TEM) pattern of NiCoFe-LDH obtained in Example 1;

[0026] Figure 4 : is a linear sweep voltammetry curve of the oxygen evolution process of NiCoFe-LDH obtained in Example 1 in 1 mol / L KOH electrolyte;

[0027] Figure 5 NiCoFe obtained in Example 3 0.25 -Linear sweep voltammetry curve of oxygen evolution process of LDH in 1 mol / L KOH electrolyte;

[0028] Figure 6: This is a linear sweep voltammetry curve of the oxygen evolution process of NiCoFe-LDH obtained in Example 1 in 1 mol / L KOH seawater electrolyte;

[0029] Figure 7 This is the time-current curve of the oxygen evolution process of the FeCoNi LDH / NF obtained in Example 1 in 1 mol / L KOH seawater electrolyte. DETAILED DESCRIPTION

[0030] The following describes in detail embodiments of the present application, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0031] In the description of this application, it should be understood that the terms "upper", "lower", "horizontal", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on this application.

[0032] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. Throughout the description of this application, "plurality" means two or more, unless otherwise specifically defined.

[0033] In order to make the purpose, technical solutions and advantages of this application more clear, this application is further described in detail below with reference to the accompanying drawings and embodiments.

[0034] The method for preparing metal hydroxide provided in the present application includes the following steps S110 to S120, and the implementation method of each step is described in detail below.

[0035] Step S110: stirring the aqueous solution of iron salt, cobalt salt and nickel salt to obtain a mixed solution.

[0036] In this embodiment, in the step of stirring the aqueous solution of iron salt, cobalt salt and nickel salt to obtain a mixed solution, the molar ratio of iron ions, cobalt ions and nickel ions is 1:2:3.

[0037] Furthermore, the iron salt, the cobalt salt and the nickel salt may be iron nitrate nonahydrate (Fe(NO 3 ) 3 ·9H 2 O), cobalt nitrate hexahydrate (Co(NO 3 ) 2 ·6H 2 O) and nickel nitrate hexahydrate (Ni(NO 3 ) 2 ·6H 2 O).

[0038] It should be noted that, in practical applications, the above specific iron salts, cobalt salts and nickel salts are not limited thereto, and other compositions may also be used; for example, a mixed solution of sulfates may also be used.

[0039] In this embodiment, the molar ratio of the ferric nitrate nonahydrate, the cobalt nitrate hexahydrate, and the nickel nitrate hexahydrate is 1:2:3.

[0040] It can be understood that the stoichiometric ratio of the metal elements in the above-mentioned mixed solution is controlled to affect the electronic structure and catalytic activity of the material. When the molar ratio of the ferric nitrate nine hydrate, the cobalt nitrate hexahydrate and the nickel nitrate hexahydrate is 1:2:3 to ensure Fe:Co:Ni=1:2:3, the high nickel ratio (Ni accounts for 50%) improves the catalytic activity (Ni is an efficient active center for OER), the bridging effect of cobalt (Co accounts for 33%) is conducive to optimizing electron transport and enhancing stability, and the trivalent characteristics of iron (Fe accounts for 17%) are introduced by high-valent metal sites to adjust the charge density of the LDH layer, thereby meeting better catalytic performance.

[0041] It can be understood that by precisely controlling the ratio of ternary metal ions and solution homogeneity, a chemical foundation is laid for the electrodeposition preparation of high-performance FeCoNi LDH electrodes.

[0042] Furthermore, the total concentration of metal ions in the mixed solution is 0.04-0.07 mol / L, and the metal molar ratio is 1:2:3.

[0043] It can be understood that the total concentration of metal ions in the mixed solution is related to the subsequent deposition rate and film thickness. When the total concentration of metal ions in the mixed solution is smaller, the deposition is slower and the film thickness is thinner. When the total concentration of metal ions in the mixed solution is larger, the deposition is faster and the film thickness is thicker. At low concentrations, the deposition current density is smaller (~5–10 mA / cm 2 ), the deposition time needs to be extended to 25 minutes to ensure the film thickness. Therefore, the total concentration of metal ions in the mixed solution is set between 0.04 and 0.07 mol / L to achieve better deposition effect.

[0044] In addition, when the total concentration of metal ions in the mixed solution is ≤0.07 mol / L, the ion diffusion rate matches the deposition rate, and a dense nanosheet structure is easily obtained.

[0045] It can be understood that this ratio scheme provides a reliable precursor basis for the controllable preparation of high-performance FeCoNi LDH by precisely controlling the ion concentration and ratio.

[0046] Step S120: Under a constant voltage, the metal ions in the mixed solution undergo a reduction reaction on the surface of the working electrode to generate ternary NiCoFe-LDH, that is, the metal hydroxide.

[0047] In this embodiment, under a constant voltage, the metal ions in the mixed solution undergo a reduction reaction on the surface of the working electrode to generate ternary NiCoFe-LDH, that is, the step of obtaining the metal hydroxide, specifically including the following steps: using the pretreated metal substrate as the working electrode, the carbon rod as the counter electrode, and the saturated calomel electrode as the reference electrode, using the mixed solution as the electrolyte, applying a constant voltage to deposit the metal ions in the mixed solution on the nickel surface, and then rinsing the surface of the metal substrate to obtain the metal hydroxide.

[0048] It can be understood that this embodiment is constructed through a three-electrode system, with a metal substrate as the working electrode (conductive substrate) to provide a deposition interface, a carbon rod counter electrode to form a current loop, and a saturated calomel electrode as the reference electrode to accurately control the working electrode potential.

[0049] Furthermore, the electrode potential applied relative to the saturated calomel electrode is -1.8V to -2.2V, and the strong negative potential ensures that the metal ions are fully reduced and avoids interference from the hydrogen evolution competition reaction.

[0050] Furthermore, the pressing time is 15 to 25 minutes. If the pressing time is too short, the film thickness may be insufficient, while if the pressing time is too long, the particles may agglomerate or the substrate may peel off.

[0051] Furthermore, the step of pre-treating the metal substrate specifically includes: ultrasonically cleaning the metal substrate with acetone and dilute hydrochloric acid for 10 to 15 minutes respectively, and then washing with water to obtain a clean metal substrate.

[0052] Furthermore, the nickel is one of foamed nickel, foamed cobalt and foamed copper.

[0053] It is understandable that the use of nickel foam, cobalt foam, or copper foam as a self-supporting substrate further enhances the overall performance of the catalyst. Nickel foam has excellent electrical conductivity, a good pore structure, and a large specific surface area, making it an ideal support material. Its three-dimensional open structure can provide a richer reaction surface, accelerate the transport of reactants, and effectively reduce the structural degradation of the catalyst during the electrolysis process. By electrodepositing NiCo-LDH on nickel foam, it is possible to construct a self-supporting catalyst with high catalytic activity, combining stability and efficiency.

[0054] Furthermore, in terms of optimizing catalytic performance, the introduction of Fe can significantly adjust the electronic structure and physicochemical properties of the catalyst. Fe doping can promote the formation of reactive sites and improve the overall reactivity of the catalyst. In particular, during the OER process of water electrolysis, Fe doping not only enhances the conductivity of the catalyst but also improves its stability at high current densities, thereby achieving sustained and efficient hydrogen generation. Therefore, the synergistic effect of Co and Ni combined with Fe doping will significantly improve the performance of the designed self-supporting catalyst, opening up new prospects for the practical application of electrocatalytic technology.

[0055] The preparation method of the metal hydroxide provided in the present application comprises stirring an aqueous solution of an iron salt, a cobalt salt and a nickel salt to obtain a mixed solution; under a constant voltage, the metal ions in the mixed solution undergo a reduction reaction on the surface of a working electrode to generate a ternary NiCoFe-LDH, namely the metal hydroxide. The present application directly grows a highly active and highly stable nanostructured material on a conductive substrate through an electrochemical deposition method of a trimetallic (Fe, Co, Ni) hydroxide with a specific ratio. Since the LDH is directly grown in situ only by a constant potential method, a low-cost seawater electrolysis catalyst can be constructed, avoiding the high temperature and high pressure requirements of the traditional hydrothermal method. In addition, the LDH nanosheet array structure directly grown in the present application avoids the use of a binder, thereby improving the mechanical stability and cycle life of the electrode.

[0056] The present invention utilizes a simple and efficient electrodeposition method to obtain metal hydroxides. The material exhibits a nanosheet-like appearance. The metal hydroxides prepared by the present invention can be used as NiCoFe-LDH catalysts and as anode materials for electrolytic cells. They can be applied in industrial scenarios of seawater hydrogen production. They exhibit excellent catalytic activity and stability in seawater electrolysis. In a 1 mol / L KOH seawater solution, a low overpotential of only 282 mV is required at room temperature to achieve a 100 mA cm -2 The current density is 500 mA cm -2 The present invention can effectively reduce the cost of catalyst preparation, is expected to be industrially applicable, and has great economic value.

[0057] The above technical solutions of the present application are described in detail below with reference to specific embodiments.

[0058] Example 1

[0059] (1) Dissolve 0.5 mmol of ferric nitrate nonahydrate (Fe(NO3)3·9H2O), 1.0 mmol of cobalt nitrate hexahydrate (Co(NO3)2·6H2O), and 1.5 mmol of nickel nitrate hexahydrate (Ni(NO3)2·6H2O) in 50 mL of water and stir well to obtain solution A.

[0060] (2) In a three-electrode system, clean nickel foam was used as the working electrode, a carbon rod as the counter electrode, a saturated calomel electrode as the reference electrode, and solution A as the electrolyte. A voltage of -2 V (vs. SCE) was applied for 20 min. NiCoFe-LDH was deposited on the surface of the nickel foam. The surface of the nickel foam was rinsed with clean water to obtain the target product.

[0061] Example 2

[0062] The same as Example 1, except that in step 1, the amounts of Fe(NO3)3·9H2O, Co(NO3)2·6H2O and Ni(NO3)2·6H2O were changed to 1 mmol, 2 mmol and 3 mmol, respectively, and the other conditions remained unchanged.

[0063] Example 3

[0064] The same as Example 1, except that the amount of Fe(NO3)3·9H2O in step 1 was changed to 0.25 mmol, and the amounts of other reactants and conditions remained unchanged.

[0065] Example 4

[0066] The process is the same as Example 1, except that the deposition voltage is changed to -1 V in step 2, and the amounts of other reactants and conditions remain unchanged.

[0067] Example 5

[0068] The process is the same as Example 1, except that the deposition time in step 2 can be adjusted according to the target thickness (5 minutes to 30 minutes), and the amounts of other reactants and conditions remain unchanged.

[0069] Example 6

[0070] The method is the same as Example 1, except that in step 2 the substrate is replaced from nickel foam to other porous conductive substrates such as copper foam and cobalt foam, and the amounts and conditions of other reactions remain unchanged.

[0071] Example 7

[0072] The same as Example 1, except that nitrate is replaced by sulfate in step 1, and the amounts and conditions of other reactions remain unchanged.

[0073] See also Figure 1 , is a scanning electron microscope (SEM) image of the NiCoFe-LDH obtained in the above Example 1.

[0074] The NiCoFe-LDH catalyst prepared in Example 1 was structurally characterized. Figure 1 This is a scanning electron microscope (SEM) image obtained in Example 1. Figure 2 This is a transmission electron microscope (TEM) image of the NiCoFe-LDH catalyst prepared in Example 1. Figure 3 is the X-ray diffraction peak of NiCoFe-LDH prepared in Example 1. Figure 1 It can be seen from the SEM image that the NiCoFe-LDH catalyst prepared in Example 1 of the present invention is in the form of stacked nanosheets.

[0075] See also Figure 2 , is a transmission electron microscope (TEM) image of the NiCoFe-LDH obtained in the above Example 1.

[0076] from Figure 2 It can be seen from the TEM image that NiCoFe-LDH exhibits low crystallinity, and the broad peaks of XRD also prove this argument.

[0077] See also Figure 3 , is the X-ray diffraction (XRD) pattern of NiCoFe-LDH obtained in the above Example 1.

[0078] The NiCoFe-LDH catalyst prepared in Example 1 was tested for oxygen evolution reaction performance in 1 mol / L KOH and 1 mol / L KOH seawater electrolytes. Saturated calomel was used as the reference electrode, a carbon rod was used as the counter electrode, and the catalyst-loaded nickel foam was used as the working electrode. The catalyst loading area was 0.25 cm 2 (0.5 cm × 0.5 cm), all potentials were converted to reversible hydrogen electrode potentials according to the formula. -1 Linear sweep voltammetry (LSV) tests were performed at a scan rate of 100 nm.

[0079] See also Figure 4 , is a linear sweep voltammetry curve of the oxygen evolution process of NiCoFe-LDH obtained in Example 1 above in 1 mol / L KOH electrolyte.

[0080] Figure 4 The linear sweep voltammetry curve of the NiCoFe-LDH catalyst prepared in Example 1 during oxygen evolution in 1 mol / L KOH electrolyte is shown in the figure. As can be seen from the figure, only 238 mV and 309 mV overpotentials are required to achieve 100 mA cm -2 and 500mA cm -2 The current density shows that the NiCoFe-LDH catalyst material prepared by the present invention has excellent electrochemical performance.

[0081] See also Figure 5 , is a linear sweep voltammogram of the oxygen evolution process of NiCoFe-LDH obtained in Example 1 above in 1 mol / L KOH electrolyte.

[0082] Figure 5NiCoFe prepared in Example 3 0.25 The linear sweep voltammetry curve of the -LDH catalyst in the oxygen evolution process in 1 mol / L KOH electrolyte shows that when the voltage reaches 100 mA cm -2 , the oxygen evolution overpotential is 250 mV, and its performance is lower than that of the NiCoFe-LDH catalyst prepared in Example 1. This result shows that the amount of iron has an impact on the catalytic performance. When the iron content is low, there are fewer catalytic active sites, resulting in decreased performance.

[0083] See also Figure 6 , is a linear sweep voltammetry curve of the oxygen evolution process of NiCoFe-LDH obtained in Example 1 above in 1 mol / L KOH seawater electrolyte.

[0084] Figure 6 The linear sweep voltammetry curve of the NiCoFe-LDH catalyst prepared in Example 1 during oxygen evolution in 1 mol / L KOH seawater electrolyte is shown in the figure. As can be seen from the figure, only 282 mV and 381 mV overpotentials are required to achieve 100 mA cm -2 and 500mAcm -2 The current density shows that the NiCoFe-LDH catalyst material prepared by the present invention has excellent electrochemical performance.

[0085] See also Figure 7 , is the time-current curve of the oxygen evolution process of NiCoFe-LDH obtained in Example 1 in 1 mol / L KOH seawater electrolyte.

[0086] Figure 7 The time-voltage curve of the oxygen evolution process of the NiCoFe-LDH catalyst prepared in Example 1 in 1 mol / L KOH seawater electrolyte shows that at a current density of 500 mA cm -2 When the catalyst is heated to 100 °C, the catalyst can be stable for at least 320 hours, indicating that the NiCoFe-LDH catalyst material of the present invention has excellent stability.

[0087] It can be understood that the various technical features of the above-described embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the various technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0088] The above are merely preferred embodiments of the present application and only specifically describe the technical principles of the present application. These descriptions are intended only to explain the principles of the present application and should not be construed in any way as limiting the scope of protection of the present application. Based on the explanations herein, any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present application, as well as other specific implementations of the present application that can be conceived by those skilled in the art without inventive effort, shall be included within the scope of protection of the present application.

Claims

1. A method for preparing a metal hydroxide, characterized in that: stirring aqueous solutions of iron salt, cobalt salt and nickel salt to obtain a mixed solution; Under a constant voltage, the metal ions in the mixed solution undergo a reduction reaction on the surface of the working electrode to generate ternary NiCoFe-LDH, that is, the metal hydroxide.

2. The method for preparing a metal hydroxide according to claim 1, wherein In the step of stirring the aqueous solutions of iron salt, cobalt salt and nickel salt to obtain a mixed solution, the molar ratio of iron ion, cobalt ion and nickel ion is (0.5-1.5):(1.5-2.5):(2-4).

3. The method for preparing a metal hydroxide according to claim 1 or 2, wherein: The mixed solution is a mixed solution of nitrates or sulfates.

4. The method for preparing a metal hydroxide according to claim 1 or 2, wherein: The total concentration of metal ions in the mixed solution is 0.04-0.07 mol / L.

5. The method for preparing a metal hydroxide according to claim 1, wherein Under a constant voltage, the metal ions in the mixed solution undergo a reduction reaction on the surface of the working electrode to generate ternary NiCoFe-LDH, that is, the step of obtaining the metal hydroxide includes the following sub-steps: The pretreated metal substrate is used as the working electrode, the carbon rod is used as the counter electrode, the saturated calomel electrode is used as the reference electrode, the mixed solution is used as the electrolyte, a constant voltage is applied to allow the metal ions in the mixed solution to be deposited on the surface of the working electrode, and then the surface of the working electrode is rinsed to obtain the metal hydroxide.

6. The method for preparing a metal hydroxide according to claim 5, wherein The constant voltage is -1.8 V to -2.2 V relative to the electrode potential of a saturated calomel electrode (vs. SCE), and the pressure is applied for 15 to 25 minutes.

7. The method for preparing a metal hydroxide according to claim 5, wherein The step of pre-treating the metal substrate specifically includes: ultrasonically cleaning the metal substrate with acetone and dilute hydrochloric acid for 10 to 15 minutes respectively, and then washing with water to obtain a clean metal substrate.

8. The method for preparing a metal hydroxide according to claim 6, wherein The substrate may be one of nickel foam, cobalt foam and copper foam.

9. A metal hydroxide, characterized in that The compound is prepared by the preparation method according to any one of claims 1 to 8.

10. An electrolytic cell, characterized in that An anode material is included, wherein the anode material includes the metal hydroxide according to claim 9.

11. Use of the electrolytic cell according to claim 10 in seawater electrolysis.

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