B, p co-doped ni fe-based alkaline electrode material and its preparation and electrolysis of seawater application

Abstract

This paper describes a B / P co-doped NiFe-based alkaline electrode material, its preparation, and its application in seawater electrolysis, belonging to the technical field of electrochemical energy storage materials. The preparation method uses nickel nitrate hexahydrate and ferrous sulfate heptahydrate as metal salts, dissolved in deionized water. A nickel foam substrate is immersed in the completely dissolved mixture at room temperature, and the resulting catalyst is placed in an oven and allowed to cool naturally to room temperature. The material is then removed, treated in a beaker with a mixed solution of NaBH4 and NaOH, and calcined again in a tube furnace, allowed to cool naturally to room temperature, and finally, phosphide is synthesized on the catalyst in a tube furnace to obtain the final catalyst. This method is simple to operate, requires no complicated solvothermal reactions, and is easy to prepare on a large scale. In a standard three-electrode system, the prepared electrocatalyst is used as the anode in a 1 M KOH + natural seawater electrolysis system for electrocatalytic reaction; the electrocatalyst exhibits excellent water splitting activity and stability.

Description

Technical Field

[0001] This invention relates to the field of electrocatalytic hydrogen production technology, specifically to a non-metallic B and P co-doped oxide NiFe-based alkaline seawater electrolytic electrode material, its preparation method, and its application, particularly suitable for the oxygen evolution reaction (OER) of direct alkaline seawater electrolysis. Background Technology

[0002] With the intensification of global climate change and the need for energy system transformation, clean hydrogen production technology has become a research hotspot. Water electrolysis has become a core technology for high-purity hydrogen production due to its scalability and sustainability. Direct seawater electrolysis eliminates the dependence on high-purity water and is an important development direction for clean hydrogen production; however, seawater has a high concentration of Cl... - This can trigger competition between the chloride oxidation reaction (ClOR) and the oxygen evolution reaction (OER), while also causing electrode corrosion, leading to a decline in electrolytic performance and a deterioration in stability.

[0003] The alkaline design principle can expand the thermodynamic potential window of OER and ClOR to 490 mV, achieving preferential selectivity for OER. Therefore, developing OER catalysts with high activity and strong corrosion resistance under alkaline conditions is key to direct alkaline seawater electrolysis for hydrogen production. OER involves complex four-electron transfer steps with high overpotentials. Researchers mainly optimize reaction kinetics through catalyst surface and electronic structure engineering, among which elemental doping is an effective method to improve catalytic activity.

[0004] In existing technologies, single-element doped catalysts have performance bottlenecks: focusing solely on single-element doping makes it difficult to achieve synergistic optimization of activity, selectivity, and stability. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a non-metallic B and P co-doped NiFe-based alkaline seawater electrolytic electrode material, its preparation method, and its application. By precisely controlling the NiFe-based catalyst through B and P co-doping, the problems of low catalytic activity, poor stability, and insufficient selectivity caused by single-element doping are solved. At the same time, a simple and scalable preparation method is provided, and the obtained catalyst exhibits excellent comprehensive performance in alkaline seawater electrolysis (OER).

[0006] To achieve the above objectives, the present invention adopts the following technical solution: a method for preparing a non-metallic B and P co-doped NiFe-based alkaline electrocatalytic material for seawater electrolysis, comprising the following steps:

[0007] (1) Nickel foam pretreatment;

[0008] (2) Ni(NO3)2·6H2O and FeSO4·7H2O were dissolved in water at a molar ratio of 1:1 to prepare a mixed solution of metal salts; the pretreated nickel foam was immersed in the mixed solution of metal salts for reaction; and then calcined in a muffle furnace to obtain NiFe;

[0009] (3) Dissolve NaBH4 and NaOH in water to prepare a boron source mixed solution. Immerse NiFe in the boron source mixed solution to react. After taking it out, calcine it in a muffle furnace at 200-400 °C to obtain NiFeB;

[0010] (4) NiFeB is placed in a tube furnace with N2 flowing through it. NaH2PO2 is placed upstream of the catalyst as a phosphorus source. The temperature is raised to 200-400 ℃ and kept at that temperature. After natural cooling, the NiFe-based alkaline electrocatalytic electrode material for seawater electrolysis, co-doped with B and P, is obtained.

[0011] Furthermore, in step (1), the pretreatment involves sonicating in 0.1 M HCl, then sonicating in an ethanol-water mixture, and drying for later use.

[0012] Furthermore, in step (2), the calcination temperature is 280-350 ℃, the calcination time is 1.5-3 h, and the heating rate is 3-5 ℃·min. -1 .

[0013] Furthermore, in step (3), the molar ratio of NaBH4 to NaOH is 1:(1.5-3), and the concentration of NaBH4 in the boron source mixed solution is 0.008-0.015 mol·L⁻¹. -1 .

[0014] Furthermore, in step (3), the heating rate of the muffle furnace is 3-5 ℃·min. -1 In step (4), the heating rate is 3-5℃·min. -1 .

[0015] The non-metallic B and P co-doped NiFe-based alkaline electrocatalytic electrode material for seawater electrolysis was prepared using the method described above.

[0016] The electrode material uses nickel foam as a substrate, with a NiFe-based electrocatalyst co-doped with B and P supported on its surface. The catalyst contains Ni... 3+ / Ni 2+ The molar ratio is 1.18, Fe 3+ / Fe 2+ With a molar ratio of 1.27, B and P are uniformly distributed on the catalyst surface and form BO, B-Ni, B-Fe, and PO bonded structures.

[0017] The application of the B, P co-doped NiFe-based alkaline seawater electrocatalytic electrode material in the direct alkaline seawater electrolysis oxygen removal reaction.

[0018] The alkaline seawater is a mixture of 1 M KOH and pretreated natural seawater. The pretreatment method for the natural seawater is as follows: take natural seawater, filter to remove silt, add 1 M KOH to remove some calcium and magnesium ions, filter again, and take the supernatant to obtain the solution.

[0019] Using the aforementioned electrode material as the working electrode, Hg / HgO as the reference electrode, and a carbon rod as the counter electrode, a three-electrode system was constructed to carry out the oxygen evolution reaction in alkaline seawater electrolyte.

[0020] This invention provides a non-metallic B and P co-doped oxide NiFe-based alkaline seawater electrocatalytic electrode material, with nickel foam (NF) as the substrate and boron and phosphorus co-doped NiFe-based active components loaded on the surface, denoted as P-NiFeB; in the catalyst, B and P are uniformly distributed on the catalyst surface and form BO, BM (M=Ni / Fe), and PO bonded structures.

[0021] This invention provides a method for preparing a non-metallic B and P co-doped NiFe-based alkaline seawater electrolytic electrode material, comprising the following steps:

[0022] For nickel foam pretreatment, the nickel foam was cut into 3 cm × 2 cm × 0.1 cm pieces and then ultrasonically cleaned in 0.1 M HCl for 20 min (to remove the surface oxide layer and impurities) and in ethanol for 15 min (to remove organic impurities). After cleaning, the pieces were dried and ready for use.

[0023] Preparation of NiFe precursor: 1.74 g Ni(NO3)2·6H2O and 1.6651 g FeSO4·7H2O (Ni:Fe molar ratio 1:1) were dissolved in 40 mL of ultrapure water to prepare a mixed metal salt solution with pH ≈ 5. Pretreated nickel foam was immersed in this mixed solution for 3 min, then removed and dried under an infrared lamp. This immersion-drying operation was repeated 3 times to ensure uniform metal salt loading on the surface of the nickel foam. Subsequently, the metal salt-loaded nickel foam was placed in a muffle furnace and dried at 5 ℃·min. -1 The heating rate was increased to 300 °C, and the calcination was carried out for 2 h. After natural cooling, the NiFe precursor was obtained.

[0024] To prepare NiFeB, 0.1135 g NaBH4 (0.3 mmol) and 0.2474 g NaOH were dissolved in 30 mL of water to prepare a boron source mixed solution. The NiFe precursor was immersed in the boron source mixed solution for 15 min, then removed and placed in a muffle furnace at 5 °C·min.-1 The heating rate was increased to 300 °C, and the mixture was calcined at that temperature for 2 h. After natural cooling, NiFeB was obtained.

[0025] The NiFeB catalyst was prepared by placing NiFeB in a tube furnace purged with high-purity N2. 100 mg of NaH2PO2 was placed in a quartz boat upstream of the catalyst as a phosphorus source, ensuring that the N2 carried the phosphorus source vapor to the catalyst surface. The catalyst was prepared at 5 °C / min. -1 The tube furnace was heated to 300 °C at a certain heating rate, held for 20 min, and then naturally cooled to room temperature to obtain the oxygen vacancy coupled boron-phosphorus co-doped NiFe-based catalyst P-NiFeB.

[0026] This invention provides the application of the above-mentioned non-metallic B and P co-doped oxide NiFe-based alkaline seawater electrocatalytic electrode material in the direct alkaline seawater electrolytic oxygen evolution reaction. Specifically, the P-NiFeB catalyst is used as the working electrode, Hg / HgO is used as the reference electrode, and a carbon rod is used as the counter electrode to construct a three-electrode system for carrying out the oxygen evolution reaction (OER) in alkaline seawater electrolyte.

[0027] The alkaline seawater is a mixture of 1 M KOH and pretreated natural seawater. The pretreatment method for the natural seawater is as follows: take natural seawater from Dalian Heishijiao Park, filter it to remove silt, add 1 M KOH to remove some calcium and magnesium ions, filter it again to take the supernatant, and then obtain the pretreated natural seawater. Mix 1 M KOH with the pretreated natural seawater as an electrolyte.

[0028] The oxygen evolution reaction was carried out at room temperature, and before the test, it was first tested at 50 mV·s. -1 Cyclic voltammetry (CV) was performed at a scan rate to remove impurities from the electrode surface and activate the electrode; linear sweep voltammetry (LSV) was performed at 5 mV·s. -1 Under 90% IR compensation conditions, all potentials are converted to a reversible hydrogen electrode (RHE) using the formula: E RHE = E Hg / HgO +0.098 V +0.059 V×pH.

[0029] This invention employs an immersion method, utilizing the precise control of B and P nonmetals over NiFe oxides, to successfully prepare a P-NiFeB electrocatalyst on a nickel foam substrate through a series of immersion and calcination reactions, eliminating the need for complex solvothermal reactions. Compared with existing technologies, this invention has the following advantages:

[0030] 1. The catalyst of this invention exhibits excellent electrocatalytic activity in alkaline seawater electrolysis of OER, at 10 mA·cm⁻¹. -2 500 mA·cm -2 1000 mA·cm-2 The overpotentials at current densities are only 207 mV, 321 mV, and 358 mV, and the Tafel slope is as low as 65.88 mV·dec. -1 It exhibits superior reaction kinetics; simultaneously, it has the lowest charge transfer resistance, a large electrochemical surface area, and a significantly increased density of active sites.

[0031] 2. The catalyst of the present invention has high selectivity for OER and produces almost no active chlorine after 10,000 CV cycles, effectively avoiding competition between ClOR and OER. At the same time, the passivation layer formed by PO bonds and the inert protective layer of BO can inhibit the erosion of active sites by Cl⁻, greatly improving corrosion resistance.

[0032] 3. The catalyst of this invention exhibits excellent stability at 250 mA·cm⁻¹. -2 It can operate stably for at least 1100 hours at 500 mA·cm⁻¹. -2 and 1 A·cm -2 It can operate stably for 400 hours and 590 hours respectively without performance degradation, meeting the requirements of industrial-grade electrolytic hydrogen production.

[0033] 4. The preparation method of the present invention adopts a two-step process of soaking and calcination, which is simple, convenient to operate, and uses readily available raw materials. It does not require complex equipment, can be prepared on a large scale, and has mild reaction conditions, low energy consumption, and is environmentally friendly, making it suitable for industrial promotion.

[0034] 5. The catalyst of the present invention uses nickel foam as a base, which has good electrical conductivity and mechanical stability. It is tightly bound to the active components and is not easy to fall off. It can be used directly as a self-supporting electrode without the need for additional binders, thus simplifying the construction of the electrolysis device. Attached Figure Description

[0035] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below.

[0036] Figure 1 The images show the scanning electron microscope (SEM) images and energy dispersive spectroscopy (EDS) spectra of the prepared P-NiFeB; where (a) and (b) are SEM images of NiFe; (c) and (d) are SEM images and EDS spectra of NiFeB, respectively; and (e) and (f) are SEM images and EDS spectra of P-NiFeB.

[0037] Figure 2 X-ray diffraction patterns and Raman spectra of the prepared P-NiFeB and its comparative sample are shown.

[0038] Figure 3(a) shows the CV curves of the prepared NiFeB and its NiFe; (b) shows the LSV curves of the prepared P-NiFeB and its comparative sample; (c) shows the Tafel slope of the prepared P-NiFeB and its comparative sample; and (d) shows the electrochemical active surface area of ​​the prepared P-NiFeB and its comparative sample.

[0039] Figure 4 The curves (ac) in the middle are the CV curves of the prepared P-NiFeB and its comparative sample.

[0040] Figure 5 EIS spectra of P-NiFeB prepared by chemiluminescence (ac) and its comparative sample at different potentials.

[0041] Figure 6 (a) shows the UV curve of the prepared P-NiFeB electrolyte after CV testing, determined by the o-toluidine colorimetric method for hypochlorous acid concentration; (b) shows the color comparison graph after CV testing with different concentrations of hypochlorous acid and 10,000 cycles, and the blank control group deionized water.

[0042] Figure 7 (ac) represents the P-NiFeB obtained at current densities of 250, 500, and 1000 mA·cm⁻¹. -2 IT tests.

[0043] Figure 8 The image shows a scanning electron microscope (SEM) image of the prepared P-NiFeB after a stability test.

[0044] Figure 9 X-ray diffraction patterns and Raman spectra of the prepared P-NiFeB before and after stability testing. Detailed Implementation

[0045] To make the present invention concise and easy to understand, the following embodiments are preferred, and detailed descriptions are provided in conjunction with the accompanying drawings. Unless otherwise specified, all raw materials are available from publicly available commercial sources.

[0046] Example 1B: Preparation of P-co-doped NiFe-based alkaline electrode material

[0047] (1) Cut the nickel foam into 3 cm × 2 cm × 0.1 cm pieces, sonicate in 0.1 M HCl for 20 min, then sonicate in an ethanol-water mixture (v / v = 1:1) for 15 min, and dry for later use;

[0048] (2) Dissolve 1.74 g Ni(NO3)2·6H2O and 1.6651 g FeSO4·7H2O in 40 mL of ultrapure water (pH≈ 5), immerse the pretreated nickel foam in the solution for 3 min, dry it under an infrared lamp, and repeat 3 times; then calcine it in a muffle furnace at 300℃ for 2 h with a heating rate of 5℃·min. -1 NiFe was obtained;

[0049] (3) Dissolve 0.1135 g NaBH4 and 0.2474 g NaOH in 30 mL of water, immerse NiFe in the solution for 15 min, remove it and calcine it in a muffle furnace at 300 ℃ for 2 h, with a heating rate of 5 ℃·min. -1 NiFeB was obtained;

[0050] (4) Place NiFeB / NF in a tube furnace with N2 flowing through it, and place 100 mg NaH2PO2 upstream. Heat at 5 °C·min -1 The temperature was raised to 300 °C, held for 20 min, and then cooled to obtain the P-NiFeB catalyst.

[0051] Example 2: Application of seawater electrolysis catalyst

[0052] The application of the P-NiFeB catalyst in direct alkaline seawater electrolysis OER involves the following steps:

[0053] Preparation of alkaline seawater: Natural seawater from Dalian Heishijiao Park was taken, filtered to remove silt, 1 M KOH was added to remove calcium and magnesium ions, and the supernatant was obtained by filtration again; 1 M KOH was mixed with the supernatant to obtain alkaline seawater electrolyte;

[0054] Construction of the three-electrode system: P-NiFeB prepared in Example 1 was used as the working electrode, Hg / HgO was used as the reference electrode, and carbon rod was used as the counter electrode;

[0055] OER performance testing: At room temperature, first at 50 mV·s -1 Perform CV testing to activate the electrode; then at 5 mV·s -1 LSV testing was performed under 90% IR compensation, and the potential was converted to RHE (E RHE = E Hg / HgO Stability was tested using the chronopotential method (+0.098 V +0.059 V × pH) and electrochemical impedance spectroscopy (EIS) was performed at frequencies of 0.1–100,000 Hz.

[0056] Example 3

[0057] Structural characterization: The prepared P-NiFeB, NiFeB and NiFe were directly applied to characterization and analysis processes such as X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and Raman spectroscopy.

[0058] Figure 1 In the image, (a) and (b) are scanning electron microscope (SEM) images of NiFe; (c) and (d) are SEM images and energy dispersive spectroscopy (EDS) spectra of NiFeB, respectively; and (e) and (f) are SEM images and EDS spectra of P-NiFeB. Figure 1 The SEM image shows that NiFe has a sea urchin-like appearance. After treatment with NaBH4, the spikes disappear. The EDS spectrum shows that B, Ni and Fe are evenly distributed. The surface of the phosphated catalyst P-NiFeB is nano-flower-like, and B, P, Ni and Fe are evenly distributed.

[0059] from Figure 2 The XRD and Raman spectra show that characteristic peaks (20 1) and (1 0 2) planes belonging to NiFeB appear near 28.4 ° and 40.6 ° (PDF#35-1317). Through the characteristic vibration peaks of metal-oxygen bonds such as Ni-O and Fe-O in the Raman spectrum, it can be clearly proved that the main body of the three catalysts is NiFe-based oxide structure. After B and P doping, the orderliness of the oxide phase and the stability of metal-oxygen bonds are further improved. P is also doped into the oxide lattice in the form of PO bonds, and finally P-doped NiFeB-based oxide catalysts are formed.

[0060] Electrochemical testing: Electrochemical performance is an important indicator for evaluating the quality of electrocatalysts. From... Figure 3 It can be seen that in alkaline seawater electrolyte, Figure 3 In (a), B doping effectively reduces Ni 2+ Oxidized to Ni 3+ The oxidation potential makes Ni species more easily oxidized into high-valence active phases. Figure 3 In (b) and (c), the P-NiFeB catalyst at 10 mA·cm -2 500 mA·cm -2 1000mA·cm -2 The overpotentials were 207 mV, 321 mV, and 358 mV, respectively, and the Tafel slope was 65.88 mV·dec. -1 It is significantly superior to NiFe and NiFeB catalysts. Figure 3 In the middle (d), P-NiFeB has the largest active surface area, indicating that P-NiFeB has more active sites.

[0061] Figure 4In the study, the performance of three materials—NiFe, NiFeB, and P-NiFeB—in the range of 20–120 mV·s was compared. -1 Cyclic voltammetry (CV) curves within the scan rate range, showing the performance of pure NiFe catalyst at high scan rates (120 mV·s). -1 The upper limit of the current density under these conditions is only about 0.10 mA·cm. -2 Overall, the electrochemical response was weak; the performance of NiFeB catalysts doped with a single element (B) was slightly improved, with some improvement in current density amplitude, but the improvement was limited; while the P-NiFeB catalysts co-doped / treated with P element exhibited significantly optimized electrochemical activity, reaching 120 mV·s⁻¹. -1 The upper limit of current density at scan rate exceeds 0.10 mA·cm. -2 The highest value is close to 0.20 mA·cm -2 Among the three, this material exhibits the best charge storage capacity and electrochemical response intensity. This result demonstrates that boron doping can moderately modulate the electronic structure and active sites of the NiFe catalyst, while the synergistic introduction of phosphorus further optimizes the ion transport efficiency and charge transfer kinetics, significantly enhancing its electrochemical activity and charge storage performance, thus improving its electrochemical catalytic performance.

[0062] Figure 5 The figures show the Nyquist curves for NiFeB, NiFe, and P-NiFeB at potentials of 1.29–1.84 V vs RHE. NiFe exhibits the highest impedance amplitude and the slowest charge transfer kinetics. B-doped NiFeB shows a significant decrease in impedance and an improvement in interfacial charge transfer efficiency. P-co-doped P-NiFeB demonstrates the best kinetic performance, with a further reduction in charge transfer resistance, confirming that B and P co-doping can effectively optimize the interfacial impedance and electrocatalytic reaction kinetics of NiFe-based catalysts. The figure also shows that P-NiFeB has the lowest impedance.

[0063] Selectivity: From Figure 6 The UV curves show that after 10,000 CV cycles, the o-toluidine colorimetric method showed that there was almost no active chlorine in the electrolyte, indicating that the catalyst has high selectivity for OER.

[0064] Stability: From Figure 7 The it curve shows that the P-NiFeB catalyst at 250 mA·cm⁻¹... -2 Stable operation for over 1100 hours at 500 mA·cm -2 Stable operation for 400 hours, 1 A·cm -2 After 590 hours of stable operation, there was no performance degradation. Figure 8 The SEM images show that the catalyst bulk structure remains intact after the reaction, with no aggregation or collapse. Figure 9 The XRD and Raman spectra show that the structure of P-NiFeB did not change significantly before and after the reaction, further proving that its structure is stable.

[0065] The boron-phosphorus co-doped NiFe-based catalyst prepared by this invention has high activity, high selectivity, and high stability. The preparation process is simple and scalable. It can be directly used as a self-supporting electrode in the field of direct alkaline seawater electrolysis for hydrogen production. It solves the problems of low catalyst activity, poor stability, and insufficient selectivity in existing seawater hydrogen production catalysts. At the same time, it eliminates the dependence on high-purity water and reduces the cost of hydrogen production. It has significant industrial application value and market prospects.

[0066] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a non-metallic B and P co-doped NiFe-based alkaline electrocatalytic material for seawater electrolysis, characterized in that, Includes the following steps: (1) Nickel foam pretreatment; (2) Ni(NO3)2·6H2O and FeSO4·7H2O were dissolved in water at a molar ratio of 1:1 to prepare a mixed solution of metal salts; the pretreated nickel foam was immersed in the mixed solution of metal salts for reaction; and then calcined in a muffle furnace to obtain NiFe; (3) Dissolve NaBH4 and NaOH in water to prepare a boron source mixed solution. Immerse NiFe in the boron source mixed solution to react. After taking it out, calcine it in a muffle furnace at 200-400 °C to obtain NiFeB; (4) NiFeB is placed in a tube furnace with N2 flowing through it. NaH2PO2 is placed upstream of the catalyst as a phosphorus source. The temperature is raised to 200-400 ℃ and kept at that temperature. After natural cooling, the NiFe-based alkaline electrocatalytic electrode material for seawater electrolysis, co-doped with B and P, is obtained.

2. The preparation method according to claim 1, characterized in that: In step (1), the pretreatment involves sonicating in 0.1 M HCl, then sonicating in an ethanol-water mixture, and drying for later use.

3. The preparation method according to claim 1, characterized in that: In step (2), the calcination temperature is 280-350 ℃, the calcination time is 1.5-3 h, and the heating rate is 3-5 ℃·min. -1 .

4. The preparation method according to claim 1, characterized in that: In step (3), the molar ratio of NaBH4 to NaOH is 1:(1.5-3), and the concentration of NaBH4 in the boron source mixed solution is 0.008-0.015 mol·L⁻¹. -1 .

5. The preparation method according to claim 1, characterized in that: In step (3), the heating rate of the muffle furnace is 3-5℃·min. -1 In step (4), the heating rate is 3-5 ℃·min. -1 .

6. A non-metallic B and P co-doped NiFe-based alkaline electrocatalytic electrode material for seawater electrolysis, characterized in that: The electrode material is prepared by the preparation method described in any one of claims 1-5.

7. The non-metallic B, P co-doped NiFe-based alkaline seawater electrolytic electrode material according to claim 6, characterized in that: The electrode material is based on nickel foam, with a NiFe-based electrocatalyst co-doped with B and P loaded on its surface. In the catalyst, B and P are uniformly distributed on the catalyst surface and form BO, B-Ni, B-Fe, and PO bonded structures.

8. The application of the B, P co-doped NiFe-based alkaline seawater electrocatalytic electrode material as described in claim 6 or 7 in the alkaline seawater electrolytic oxygen removal reaction.

9. The application according to claim 8, characterized in that, The alkaline seawater is a mixture of 1 M KOH and pretreated natural seawater. The pretreatment method for the natural seawater is as follows: take natural seawater, filter to remove silt, add 1 M KOH to remove some calcium and magnesium ions, filter again, and take the supernatant to obtain the solution.

10. The application according to claim 8, characterized in that, Using the aforementioned electrode material as the working electrode, Hg / HgO as the reference electrode, and a carbon rod as the counter electrode, a three-electrode system was constructed to carry out the oxygen evolution reaction in alkaline seawater electrolyte.

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