A nickel-based chlorine corrosion resistant electrode and a preparation method and application thereof

Abstract

This invention provides a nickel-based chlorine-resistant electrode, its preparation method, and its application, belonging to the field of new materials technology. The invention involves diluting an inorganic acid solution with water to prepare a dilute acid solution, thus obtaining a etching solution. A metallic nickel substrate is then immersed in the etching solution. Afterward, the substrate is dried twice at 60°C. The resulting nickel electrode is then electrochemically reconstructed to obtain the nickel-based chlorine-resistant electrode. This invention has advantages such as simple process and equipment, low cost, and simple post-processing. The nickel-based chlorine-resistant electrode obtained by this invention has excellent application prospects in catalytic seawater electrolysis reactions.

Description

Technical Field

[0001] This invention belongs to the field of new materials technology, and in particular relates to a nickel-based chlorine-resistant electrode, its preparation method and application. Background Technology

[0002] Seawater electrolysis can utilize renewable energy sources such as offshore wind and solar power, converting vast seawater resources into seawater energy. Therefore, seawater electrolysis has broad development prospects. However, chloride ions in seawater undergo an anodic competition reaction during electrolysis, and the resulting hypochlorite ions severely corrode the electrodes, reducing the lifespan of the electrode materials.

[0003] Existing technologies can achieve a certain degree of resistance to chloride corrosion by modifying the surface of electrode materials with a layer of oxyacid ions or oxides as a protective layer. However, the introduced foreign acid ions are unstable and easily fall off during the reaction process, causing secondary pollution to the electrolyte. At the same time, the additional protective layer also increases the material preparation cost and process flow, limiting the large-scale production and application of the material.

[0004] The key to chlorine corrosion resistance technology lies in the formation of a high-oxidation-state Lewis acid layer on the catalyst surface, which adsorbs hydroxide ions in the electrolyte, thus repelling chloride ions. Nickel-based materials exhibit good oxygen evolution performance in water electrolysis and readily form a high-oxidation-state nickel hydroxyl oxide layer after electrooxidation, significantly improving the stability of seawater electrolysis. This fully demonstrates the enormous potential of high-oxidation-state Lewis acid layers in seawater electrolysis chlorine corrosion resistance applications, making the development of nickel-based chlorine corrosion resistant electrodes of significant scientific and technological importance. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention proposes a nickel-based chlorine-resistant electrode, its preparation method, and its applications. The method of this invention enables the simple preparation of nickel-based chlorine-resistant electrodes, offering advantages such as simple processes and equipment, low cost, and easy post-processing, facilitating large-scale production. The nickel-based chlorine-resistant electrode obtained by this invention shows promising application prospects in catalytic seawater electrolysis reactions.

[0006] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a method for preparing a nickel-based chlorine-resistant electrode, comprising the following steps: Inorganic acid is diluted with water to obtain a dilute acid solution, which is used as a etching solution; The nickel substrate is immersed in the etching solution; The impregnated nickel metal substrate is dried for the first time. Rinse the surface of the nickel substrate after the first drying with clean water to remove impurities, and then perform a second drying to obtain a dried nickel electrode. The dried nickel electrode is subjected to an electrochemical reconstruction reaction to obtain the nickel-based chlorine-resistant electrode.

[0007] Technical Principle: This invention uses a dilute acid etching solution to etch the surface of a metallic nickel substrate. Through the slight corrosion reaction between the acid and nickel and the in-situ growth process of the etching solution, a low-valence nickel oxide / hydroxide precursor layer is generated on the substrate surface, laying the material basis for the formation of a high-oxidation-state anti-corrosion layer. On the other hand, the acid etching process creates an uneven, rough structure on the nickel substrate surface, increasing the substrate's specific surface area and providing more active sites for subsequent electrochemical reconstruction to form a catalytic / anti-corrosion layer. The two drying steps are not simply dehydration and drying. The first drying process ensures uniform evaporation of the etching solution on the nickel substrate surface, allowing the precursors generated by the corrosion reaction to adhere evenly to the etched sites on the substrate, avoiding uneven distribution of the modified layer caused by local concentration inconsistencies. Rinsing with clean water removes unbonded corrosion byproducts / residual acid radicals from the surface, eliminating interference from impurities on subsequent electrochemical reactions. The second drying process ensures that the substrate surface is dry and clean, ensuring uniform contact between the electrode and the electrolyte during electrochemical reconstruction, and avoiding electrochemical reaction side effects caused by aqueous impurities.

[0008] Electrochemical reconstruction is a key step in achieving resistance to chloride corrosion. It involves electrochemically driving the oxidation of low-valence nickel species on the nickel substrate surface, forming a highly oxidized nickel hydroxyl oxide layer (NiOOH) in situ. This layer is a Lewis acid layer and can react with OH groups in the electrolyte. - Strong adsorption, utilizing electrostatic repulsion to block Cl - Migration to the electrode surface fundamentally inhibits Cl. - The anodic competitive reaction and the corrosive effect of hypochlorite are combined, and the oxide layer is in situ bonded to the nickel substrate, which solves the problem of easy peeling of traditional coatings and takes into account both conductivity and structural stability.

[0009] Furthermore, the inorganic acid includes at least one of hydrochloric acid, sulfuric acid, and nitric acid. Hydrochloric acid, sulfuric acid, and nitric acid are all strong inorganic acids that can completely dissociate into H+ in aqueous solution. + It can undergo a mild and non-violent corrosion reaction with metallic nickel, enabling surface etching and precursor generation on the nickel substrate. This avoids the problems of weak organic acids having weak dissociation ability and poor corrosion effect, or strong oxidizing acids (such as concentrated nitric acid) causing passivation of the nickel substrate and the inability to form an effective etching structure.

[0010] Furthermore, the concentration of the dilute acid solution is 0.1-2M. A concentration ≥0.1M ensures that the acid solution contains sufficient H+. + Concentration is crucial for effective etching of the nickel substrate; if the concentration is below 0.1M, H... +If the concentration is too low, the corrosion reaction rate is too slow, failing to form a sufficiently rough structure and precursor. This results in insufficient sites and uneven thickness of the subsequent electrochemically reconstructed anti-corrosion layer, significantly reducing its resistance to chloride corrosion. A concentration ≤2M keeps the corrosion reaction within a mild etching range; however, if the concentration exceeds 2M, H… + Excessive concentration leads to a violent corrosion reaction, which can cause excessive etching of the nickel substrate surface, even resulting in holes and peeling, damaging the structural integrity and conductivity of the substrate. At the same time, severe corrosion generates a large number of nickel ions, which are prone to agglomerate on the substrate surface to form amorphous impurities, interfering with subsequent electrochemical reconstruction reactions.

[0011] Furthermore, the temperature of the first drying is 60°C, and the time is 3-6 hours.

[0012] Furthermore, the second drying process is carried out at a temperature of 60°C for 3-6 hours.

[0013] Furthermore, the electrochemical reconstruction reaction employs a three-electrode system, with the dried nickel electrode as the working electrode, a 1M potassium hydroxide solution as the electrolyte, and the reconstruction method being either chronopotential or chronocurrent.

[0014] This invention employs a dried nickel electrode as the working electrode (reactant), silver / silver chloride as the reference electrode (for precise potential control and to eliminate system resistance interference), and a graphite rod as the counter electrode (to provide an electron conduction channel and ensure electronic balance in the oxidation reaction). This three-electrode system is a classic system for precise electrochemical synthesis, enabling quantitative control of the electrochemical reaction on the working electrode surface. It avoids the problems of inaccurate potential control and over / under-reaction issues inherent in two-electrode systems. A 1M KOH electrolyte provides a strongly alkaline reaction environment, on the one hand... - It is a necessary reactant for the formation of the nickel hydroxyl oxide layer. Low-valence nickel species on the nickel substrate surface react with OH under alkaline conditions. - Combined, it is electrochemically oxidized to generate NiOOH; on the other hand, the high concentration of OH in 1M KOH... - It can be pre-adsorbed onto the nickel substrate surface, providing Cl for subsequent resistance to chloride corrosion. - The repulsion lays the foundation, and KOH is a strong base, which is stable upon dissociation and free from impurity ions that interfere with the electrochemical reaction.

[0015] Furthermore, the current density applied by the chronoamperometry method is 50-500 mA per square centimeter, and the application time is 1-6 hours; The voltage applied by the chronopotential method is 1.5V-1.8V, and the application time is 1-6 hours.

[0016] Both chronopotentiometry and chronocurrent methods are electrochemical constant-parameter oxidation methods. Chronopotentiometry achieves the oxidation reaction through constant current, while chronocurrent method achieves the oxidation reaction through constant potential. Both can precisely control the time and extent of the electrochemical reaction, enabling controllable synthesis of nickel hydroxyl oxide layer thickness and valence state. This avoids the uneven oxide layer structure caused by dynamic potential methods such as cyclic voltammetry, ensuring the density and uniformity of the anti-corrosion layer.

[0017] The present invention also proposes a nickel-based chlorine-resistant electrode, which is prepared according to the above preparation method.

[0018] The present invention also proposes the application of the above-mentioned nickel-based chlorine-resistant electrode in seawater electrolysis.

[0019] Compared with the prior art, the present invention has the following advantages and technical effects: (1) The preparation process has significant advantages and is suitable for large-scale production: The raw materials used in this invention are commercially available metallic nickel substrates, inorganic acids and other conventional and readily available raw materials. The preparation process only includes simple steps such as dilute acid corrosion, two drying cycles and electrochemical reconstruction. It does not require complex equipment and cumbersome operations, resulting in low preparation cost and good repeatability. Moreover, the corrosion method allows the catalyst to be tightly bonded to the nickel substrate, avoiding the additional process of preparing and modifying the protective layer, greatly simplifying the production process, reducing industrial production costs, and facilitating the large-scale and industrialized production of nickel-based chloride corrosion resistant electrodes.

[0020] (2) Excellent electrode performance, with both conductivity and stability: The nickel-based electrode prepared by dilute acid corrosion and electrochemical reconstruction has a tight bond between the substrate and the catalyst layer, and has high conductivity, which can effectively reduce the resistance loss in the electrolysis reaction; at the same time, a stable high oxidation state nickel hydroxyl oxide layer (Lewis acid layer) is formed on the electrode surface. After the hydroxide ions in the electrolyte are adsorbed, the layer can effectively repel chloride ions, greatly improve the electrode's resistance to chloride corrosion, adapt to the harsh environment of seawater electrolysis, and can be stably applied to the anode reaction of seawater electrolysis.

[0021] (3) Solving the inherent defects of traditional protection technology: Overcoming the problem that the external modification layer is easy to fall off and cause secondary pollution to the electrolyte when the electrode surface is modified with oxyacid ion or oxide protective layer in the existing technology, the present invention forms an anti-chlorine corrosion layer in situ on the nickel substrate through electrochemical reconstruction, which is integrated with the electrode body, with no risk of falling off and no introduction of external impurities to pollute the electrolyte, thus improving the cleanliness and stability of the seawater electrolysis system.

[0022] (4) High catalytic activity and obvious advantages in electrolysis efficiency: After the electrode prepared by the present invention is regulated by dilute acid corrosion, the thickness of the surface corrosion layer and the electro-oxidation activation layer can be controlled, and the formed nickel hydroxyl oxide layer is a highly efficient oxygen evolution catalytic site. Among them, the electrode prepared by 1M hydrochloric acid corrosion shows the best electrocatalytic activity. The thickness of the chlorine corrosion-resistant layer is positively correlated with the catalytic activity, which can effectively improve the oxygen evolution efficiency of seawater electrolysis and reduce the overpotential of the electrolysis reaction.

[0023] (5) Extremely high stability and long service life: The nickel-based anti-chlorine corrosion electrode prepared by the present invention exhibits extremely high stability in the simulated seawater electrolysis environment. The electrode material of the optimal embodiment can operate stably in simulated seawater for more than 600 hours, which is far superior to the nickel-based electrode that has not undergone dilute acid corrosion treatment, greatly improving the service life of the electrode and reducing the electrode replacement frequency and maintenance cost of seawater electrolysis equipment.

[0024] (6) Revealing the anti-chlorine corrosion mechanism and having scientific guiding significance: This invention studies the formation law of nickel hydroxyl oxide layer on nickel substrate surface through electrochemical activation process, and clarifies the anti-chlorine corrosion stabilization mechanism of high oxidation state Lewis acid layer. It provides important scientific basis and technical reference for the subsequent design and development of more efficient nickel-based and other metal-based anti-chlorine corrosion electrolytic electrodes, and promotes the technological development of anti-chlorine corrosion electrode materials for seawater electrolysis.

[0025] (7) High resource utilization value and meets the needs of industrial development: The electrode prepared by this invention is specially designed for seawater electrolysis reaction, which can effectively utilize seawater resources, which account for more than 95% of the global water reserves, and combine them with renewable energy sources such as wind and solar power to produce green hydrogen from seawater electrolysis, realize the synergistic utilization of renewable energy and seawater resources, solve the problem of limited freshwater resources restricting hydrogen production by water electrolysis, and has broad industrial application prospects and resource utilization value. Attached Figure Description

[0026] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a schematic diagram of dilute acid corrosion and drying in Example 1; Figure 2 This is a schematic diagram of the electrochemical reconstruction reaction in Examples 1, 2, and 1. Figure 3 SEM images of the materials before and after electro-oxidation in Examples 1, 2, and 1 (Comparative Example 1); Figure 4 XPS image of the NF-1M material obtained in Example 1; Figure 5The image shows the in-situ Raman diagram of the NF-1M NiOOH material obtained in Example 1. Figure 6 LSV diagrams of the substrate material, electrodes of Examples 1-2 and Comparative Examples 1-3; Figure 7 This is a comparison diagram of the chlorine corrosion resistance of the materials before and after electro-oxidation in Examples 1, 2, and 1. Figure 8 The results of long-term stability testing of the NF-1M NiOOH material obtained in Example 1 are shown. Detailed Implementation

[0027] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0028] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0029] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0030] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0031] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0032] This invention provides a method for preparing a nickel-based chlorine-resistant electrode, comprising the following steps: Inorganic acid is diluted with water to obtain a dilute acid solution, which is used as a etching solution; The nickel substrate is immersed in the etching solution; The impregnated nickel metal substrate is dried for the first time. Rinse the surface of the nickel substrate after the first drying with clean water to remove impurities, and then perform a second drying to obtain a dried nickel electrode. A nickel-based chlorine-resistant electrode was obtained by electrochemical reconstruction of a dried nickel electrode.

[0033] In a preferred embodiment of the present invention, the inorganic acid includes at least one of hydrochloric acid, sulfuric acid, and nitric acid.

[0034] In a preferred embodiment of the present invention, the concentration of the dilute acid solution is 0.1-2M.

[0035] In a preferred embodiment of the present invention, the temperature of the first drying is 60°C and the time is 3-6 hours.

[0036] In a preferred embodiment of the present invention, the temperature of the second drying is 60°C and the time is 3-6 hours.

[0037] In a preferred embodiment of the present invention, the electrochemical reconstruction reaction adopts a three-electrode system, with a dried nickel electrode as the working electrode, a 1M potassium hydroxide solution as the electrolyte, and the reconstruction method is either chronopotential or chronocurrent.

[0038] In a preferred embodiment of the present invention, the current density applied by the chronoamperometry method is 50-500 mA·cm². -2 The application time is 1-6 hours; the voltage applied by the chronopotential method is 1.5V-1.8V, and the application time is 1-6 hours.

[0039] In this embodiment of the invention, the preparation method of the nickel-based chloride-resistant electrode specifically includes the following steps: Dilute a commercially available inorganic acid (at least one of hydrochloric acid, sulfuric acid, and nitric acid) with water to a 0.1-2M dilute acid solution as the etching solution. Take 2 mL of the etching solution into a porcelain boat and place a piece of foamed nickel (NF, 1×3 cm) inside. 2 After soaking, the ceramic boat is placed in a 60℃ forced-air drying oven for 3-6 hours until the solution evaporates. Impurities adhering to the surface are rinsed with clean water, and then placed in a 60℃ forced-air drying oven again for 3-6 hours until the electrolytic surface is dry. Using the obtained electrode material as the working electrode, silver / silver chloride as the reference electrode, and a graphite rod as the counter electrode, an application of 50-500 mA·cm⁻¹ is performed on the working electrode in a 1M KOH electrolyte using a chronopotentiometric method. -2 By maintaining the current density for 1-6 hours, a nickel-based chlorine-resistant electrode is obtained.

[0040] This invention also proposes a nickel-based chlorine-resistant electrode, which is prepared according to the above-described preparation method.

[0041] This invention also proposes an application of the above-mentioned nickel-based chlorine-resistant electrode in seawater electrolysis.

[0042] All raw materials used in the embodiments of this invention were purchased commercially.

[0043] The technical solution of the present invention will be further illustrated by the following embodiments.

[0044] Example 1 Dilute commercially available hydrochloric acid (HCl) with water to a 1M dilute acid solution as the etching solution; take 2mL of the etching solution into a porcelain boat, and place a piece of foamed nickel (NF, 1×3 cm) inside. 2 After soaking, the ceramic boat was placed in a 60℃ forced-air drying oven for 6 hours until the solution evaporated. Impurities adhering to the surface were rinsed with water, and the boat was again placed in a 60℃ forced-air drying oven for 6 hours until the electrolytic surface was dry. Using the obtained electrode material (denoted as NF-1M) as the working electrode, silver / silver chloride as the reference electrode, and a graphite rod as the counter electrode, a 100 mA·cm⁻¹ electrolytic flux was applied to the working electrode in a 1M KOH electrolyte using a chronopotentiometric method. -2 The current density was maintained for 3 hours to obtain a nickel-based chlorine-resistant electrode, denoted as NF-1M NiOOH.

[0045] Example 2 Dilute commercially available hydrochloric acid with water to a 0.1M solution as the etching solution. Take 2 mL of the etching solution and place it in a porcelain boat. Place a piece of foamed nickel (1×3 cm in size) inside. 2 After soaking, the ceramic boat was placed in a 60℃ forced-air drying oven for 6 hours until the solution evaporated. Impurities adhering to the surface were rinsed with water, and the boat was again placed in a 60℃ forced-air drying oven for 6 hours until the electrolytic surface was dry. Using the obtained electrode material (denoted as NF-0.1M) as the working electrode, silver / silver chloride as the reference electrode, and a graphite rod as the counter electrode, a 100 mA·cm⁻¹ electrolytic flux was applied to the working electrode in a 1M KOH electrolyte using a chronopotentiometric method. -2 The current density was maintained for 3 hours to obtain a nickel-based chlorine-resistant electrode, denoted as NF-0.1M NiOOH.

[0046] Example 3 Dilute commercially available sulfuric acid with water to a 2M dilute acid solution as the etching solution. Take 2mL of the etching solution and place it in a porcelain boat. Place a piece of foamed nickel (1×3 cm in size) inside. 2After soaking, the ceramic boat was placed in a 60℃ forced-air drying oven for 3 hours until the solution evaporated. Impurities adhering to the surface were rinsed with clean water, and the boat was again placed in a 60℃ forced-air drying oven for 3 hours until the electrolytic surface was dry. Using the obtained electrode material as the working electrode, silver / silver chloride as the reference electrode, and a graphite rod as the counter electrode, a 50 mA·cm⁻¹ electrode was applied to the working electrode in a 1M KOH electrolyte using a chronopotentiometric method. -2 The current density was maintained for 6 hours to obtain a nickel-based chlorine-resistant electrode.

[0047] Example 4 Dilute commercially available nitric acid with water to a 0.5M dilute acid solution as the etching solution. Take 2 mL of the etching solution and place it in a porcelain boat. Place a piece of foamed nickel (1×3 cm in size) inside. 2 After soaking, the ceramic boat was placed in a 60℃ forced-air drying oven and dried for 5 hours until the solution evaporated. The impurities attached to the surface were rinsed with clean water, and the surface was placed in a 60℃ forced-air drying oven and dried for another 5 hours until the electrolytic surface was dry. The obtained electrode material was used as the working electrode, silver / silver chloride as the reference electrode, and graphite rod as the counter electrode. In 1M KOH electrolyte, a voltage of 11.6V was applied by chronopotential method for 4 hours to obtain a nickel-based chlorine corrosion resistant electrode.

[0048] Comparative Example 1 Using a nickel foam electrode (NF) as the working electrode, silver / silver chloride as the reference electrode, and a graphite rod as the counter electrode, a 100 mA·cm² electrode was applied to the working electrode in a 1 M KOH electrolyte using a chronopotentiometric method. -2 The current density was maintained for 3 hours to obtain a nickel-based chlorine-resistant electrode, denoted as NF-NiOOH.

[0049] Comparative Example 2 Same as Example 1, except that electrochemical reconstruction is not performed, i.e., the chronopotential method process is omitted. The remaining steps (1M hydrochloric acid etching, two drying cycles) are the same as in Example 1, and the resulting electrode is denoted as NF-1M.

[0050] Comparative Example 3 Same as Example 1, except that electrochemical reconstruction is not performed, i.e., the chronopotential method process is omitted. The remaining steps (0.1M hydrochloric acid etching, two drying cycles) are the same as in Example 2, denoted as NF-0.1M.

[0051] Performance testing Figure 1 This is a schematic diagram of dilute acid corrosion and drying in Example 1. Figure 1The paper demonstrates the process of immersing a nickel foam substrate in hydrochloric acid etching solution, followed by drying to achieve the evaporation of the etching solution and the corrosion reaction. It clearly shows the uniform wetting characteristics of dilute acid on the surface of the nickel substrate, as well as the uniform fixation effect of the corrosion products on the substrate surface after drying. This proves the uniformity and controllability of the dilute acid etching + drying process of this invention, laying a good physical foundation for subsequent electrochemical reconstruction.

[0052] Figure 2 The diagram shows the electrochemical reconstruction reaction in Examples 1, 2 and Comparative Example 1. It can be seen that as the etching thickness increases, the thickness of the activated layer generated by electro-oxidation also increases, revealing a positive correlation between the concentration of dilute acid corrosion and the thickness of the electro-oxidized layer after electrochemical reconstruction, and proving the regulatory effect of dilute acid corrosion pretreatment on the formation of the electro-oxidized layer.

[0053] The surface morphology of the materials before and after electro-oxidation in Examples 1, 2, and Comparative Example 1 was observed using a scanning electron microscope (SEM). (Taking Example 1 as an example, the material before electro-oxidation was NF-1M, and the material after electro-oxidation was NF-1M NiOOH.) The results are as follows: Figure 3 As shown, compared to Comparative Example 1, the surface corrosion layer thickness of Examples 1 and 2 is increased. From the perspective of microscopic morphology, this confirms that dilute acid corrosion pretreatment can form a thicker corrosion layer on the nickel substrate surface. Furthermore, the growth of the electro-oxidation layer after electrochemical reconstruction is highly matched with the corrosion layer structure, further verifying the modification effect of corrosion pretreatment on the electrode surface structure.

[0054] The surface valence structure of the NF-1M material obtained in Example 1 was analyzed using X-ray photoelectron spectroscopy (XPS), and the results are as follows: Figure 4 As shown. Based on the binding energy analysis, it can be concluded that the surface of the Ni(OH)2 structure after corrosion synthesis in Example 1 has a +2 valence.

[0055] The surface valence structure of the NF-1M NiOOH material obtained in Example 1 was analyzed using in-situ electrochemical Raman spectroscopy. The results are as follows: Figure 5 As shown. Based on the binding energy analysis, the signal of surface nickel hydroxide material in Example 1 generating surface nickel hydroxyl oxide during the electrochemical process can be obtained. In-situ characterization confirmed that during the electrochemical reconstruction process, the Ni(OH)2 precursor on the NF-1M surface can be successfully oxidized to γ-NiOOH (high oxidation state nickel hydroxyl oxide), and this reaction is a potential-driven in-situ transformation process, clarifying the phase composition and formation mechanism of the chlorine corrosion resistant functional layer.

[0056] Electrochemical testing: A conventional three-electrode system electrochemical workstation was used, with the electrode or nickel foam (substrate material) obtained in the examples or comparative examples as the working electrode, a graphite rod as the counter electrode, and an Ag-AgCl electrode as the reference electrode.

[0057] All potentials were calibrated relative to the reversible hydrogen electrode (RHE) using the following calculation: E(vs.RHE) = E(vs.Ag-AgCl) + 0.197 + 0.059 pH. All polarization profiles were corrected for 90% IR compensation.

[0058] The solution was a 1M KOH alkaline simulated seawater electrolyte. Linear sweep voltammetry (LSV) curves for the substrate material and the electrodes of Examples 1-2 and Comparative Examples 1-3 are shown below. Figure 6 As can be seen, the electrocatalytic activity of Comparative Examples 2 and 3 (which omitted electrochemical reconstruction) was significantly lower than that of Examples 1 and 2. Furthermore, Example 1 exhibited the highest electrocatalytic activity compared to the other comparative examples, indicating that the thicker the chlorine corrosion-resistant layer, the better the activity. From the perspective of electrochemical catalytic activity, the positive correlation between dilute acid corrosion concentration and electrode oxygen evolution catalytic activity was verified. Among them, Example 1 (NF-1M NiOOH) showed the best electrocatalytic activity, proving that a thick and continuous γ-NiOOH layer can significantly improve the oxygen evolution efficiency of seawater electrolysis.

[0059] The stability analysis of seawater electrolysis is as follows: Stability analysis was performed on the materials before and after electro-oxidation in Examples 1, 2, and Comparative Example 1 in simulated seawater at four times the normal concentration. The comparison graph of chlorine corrosion resistance stability among Examples 1, 2, and Comparative Example 1 is shown below. Figure 7 As shown, the electrolytic stability of seawater was improved after electro-oxidation in Examples 1, 2, and 1, with Example 1 exhibiting the highest resistance to chlorine corrosion.

[0060] The long-term stability of the NF-1M NiOOH material obtained in Example 1 was tested in simulated seawater, and the results are as follows: Figure 8 As shown, the chlorine-resistant electrode material of Example 1 operated stably in simulated seawater for over 600 hours. During the 600-hour test, the potential of the NF-1M NiOOH electrode remained stable at around 1.8V, without significant increase or drastic fluctuation, indicating that the γ-NiOOH chlorine-resistant layer on the electrode surface was not corroded by Cl. -The electrode exhibits strong resistance to corrosion and remains firmly bonded to the nickel substrate, without any detachment or failure. Its long-term stable operation under high current density overcomes the technical bottleneck of traditional nickel-based electrodes being prone to corrosion and having short lifespans in seawater electrolysis. In simulated seawater, the electrode materials of Examples 2-4 show similar performance to those of Example 1, demonstrating that the nickel-based chlorine-resistant electrode prepared by this invention meets the core performance requirements for large-scale industrial application, providing a long-life, highly stable electrode material for the production of green hydrogen through seawater electrolysis.

[0061] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for preparing a nickel-based chlorine-resistant electrode, characterized in that, Includes the following steps: Inorganic acids are diluted with water to obtain dilute acid solutions with a concentration of 0.1-2M, which are used as etching solutions. The nickel substrate is immersed in the etching solution; The impregnated nickel substrate is first dried at 60°C for 3-6 hours. Rinse the surface of the nickel substrate after the first drying with clean water to remove impurities, and then dry it a second time at 60°C for 3-6 hours to obtain a dried nickel electrode. The dried nickel electrode was subjected to an electrochemical reconstruction reaction to obtain the nickel-based chlorine-resistant electrode; The electrochemical reconstruction reaction adopts a three-electrode system, with the dried nickel electrode as the working electrode, the electrolyte being a 1M potassium hydroxide solution, and the reconstruction method being either chronopotential or chronocurrent. The current density applied by the chronopotential method is 50-500 mA per square centimeter, and the application time is 1-6 hours; The voltage applied by the chronoamperometry method is 1.5V-1.8V, and the application time is 1-6 hours; The inorganic acid is at least one of hydrochloric acid, sulfuric acid, and nitric acid.

2. A nickel-based chlorine-resistant electrode, characterized in that, It is prepared according to the preparation method described in claim 1.

3. The application of the nickel-based chlorine-resistant electrode of claim 2 in seawater electrolysis.

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