Low-temperature pulse electrodeposition method for self-supported ni-fe ldh oxygen evolution electrode and application thereof

Abstract

The application discloses a low-temperature pulse electrodeposition preparation method of a self-supporting NiFe LDH oxygen evolution electrode and application thereof, and belongs to the technical field of electrocatalytic materials, and specifically relates to the following steps: preparing a deposition solution containing nickel salt, ferrous salt and formamide, taking a conductive substrate as a working electrode, and placing the working electrode in the deposition solution at 2-6 DEG C to perform double-potential pulse electrodeposition, and then performing washing and vacuum drying to obtain NiFe LDH nanosheet arrays which are in situ grown on the surface of the conductive substrate, and form a uniform and dense self-supporting NiFe LDH oxygen evolution electrode. Through the synergistic regulation strategy of low-temperature environment control and pulse electrodeposition, the catalyst has high electrochemical active area and high mechanical stability, and thus the apparent current density of OER and the long-time stability of catalysis are significantly improved.

Description

Technical Field

[0001] This invention belongs to the field of electrocatalytic materials technology, specifically relating to a low-temperature pulse electrodeposition method for preparing a self-supporting NiFe LDH oxygen evolution electrode and its application. Background Technology

[0002] The alkaline oxygen evolution reaction (OER) is a key half-reaction in the electrolysis of water to produce hydrogen, and its slow four-electron transfer kinetics severely limit the energy conversion efficiency of water electrolysis. Among non-precious metal catalysts, nickel-iron layered double hydroxides (NiFe LDH / NiFeOOH) are widely recognized as the best-performing OER catalyst under alkaline conditions due to their high intrinsic activity and low cost.

[0003] However, traditional supported catalysts are prone to active material detachment under high current densities. While self-supported electrodes partially alleviate this problem, they still face significant challenges: Firstly, the intense oxygen bubbles generated during long-term operation mechanically erode the catalyst layer. If the bonding force is insufficient, the thin-layer structure is easily peeled off or cracked, leading to increased electrolytic cell pressure and decreased stability. Secondly, the geometric active area of ​​existing self-supported NiFe-based (hydroxyl) catalysts is far lower than the theoretical value, limiting the apparent OER current density per unit area (typically requiring greater than 500 mA cm⁻¹). -2 Improving the effective active area of ​​a self-supporting catalyst system through morphology engineering and other measures is key to further enhancing catalytic performance at high current densities.

[0004] In summary, the development of self-supporting NiFe catalysts with both high mechanical stability and high active surface area is of great significance for promoting the industrialization of alkaline water electrolysis and anion exchange membrane water electrolysis. Summary of the Invention

[0005] To address the problems of poor mechanical stability (thin layer cracking or peeling caused by oxygen bubble erosion) and low geometric active area of ​​existing self-supported NiFe-based catalysts during long-term alkaline OER operation, this invention provides a low-temperature pulse electrodeposition method for preparing a self-supported NiFe LDH oxygen evolution electrode and its application. By suppressing excessive nucleus growth under low-temperature conditions, combined with pulse electrodeposition to promote uniform nucleation and in-situ formamide intercalation, the electrochemical active area of ​​the electrode (ECSA > 6 mF cm⁻²) is significantly increased, and the apparent reactivity of the catalyst is improved. At the same time, the interfacial bonding between the catalyst layer and the substrate is enhanced, and the catalyst can operate stably for 1000 hours without peeling in 1 M KOH electrolyte and at a current density of 1 A cm⁻².

[0006] The technical solution adopted in this invention is as follows:

[0007] A low-temperature pulse electrodeposition method for preparing a self-supporting NiFe LDH oxygen evolution electrode includes the following steps:

[0008] Step 1: Pre-treat the conductive substrate;

[0009] Step 2: Prepare a precipitation solution containing nickel salt, ferrous salt and formamide;

[0010] Step 3: Using a conductive substrate as the working electrode, perform dual-potential pulse electrodeposition in a deposition solution at 2~6 ℃;

[0011] Step 4: After deposition, the material is washed and vacuum dried to obtain an array of NiFeLDH nanosheets grown in situ on the surface of a conductive substrate, forming a uniform and dense self-supporting NiFe LDH oxygen evolution electrode.

[0012] Further, the specific process of the pretreatment described in step 1 is as follows: ultrasonic cleaning with acid solution, acetone, anhydrous ethanol and deionized water in sequence, followed by vacuum drying for later use.

[0013] Furthermore, the conductive substrate is any one of nickel foam (NF), nickel mesh, nickel foil, carbon cloth, and carbon paper, preferably nickel foam.

[0014] Further, the nickel salt mentioned in step 2 is at least one of nickel nitrate, nickel chloride, or nickel sulfate, and the concentration of Ni²⁺ in the deposition solution is 0.08~0.20 mol / L.

[0015] Further, the ferrous salt mentioned in step 2 is at least one of ferrous sulfate or ferrous chloride, and the concentration of Fe²⁺ in the precipitation solution is 0.02~0.08 mol / L.

[0016] Furthermore, the molar ratio of Ni²⁺ to Fe²⁺ in the deposition solution described in step 2 is 3:1.

[0017] Furthermore, the volume fraction of formamide in the sedimentation solution described in step 2 is 7% to 11%.

[0018] Furthermore, the solvent for the deposition solution in step 2 is deionized water.

[0019] Furthermore, the dual-potential pulse electrodeposition described in step 3 is carried out in a three-electrode system, with the reference electrode being a mercury / mercury oxide electrode (Hg / HgO) and the counter electrode being a graphite rod or platinum sheet.

[0020] Furthermore, the high potential of the dual-potential pulse electrodeposition is -0.7 to -0.9 V vs. Hg / HgO, and the low potential is -0.9 to -1.1 V vs. Hg / HgO, with a difference of 0.2 V between the high and low potentials.

[0021] Furthermore, the pulse duty cycle (high potential application time: low potential application time) of the dual-potential pulse electrodeposition is 1:2 to 2:1, and the pulse period is 1 to 10 seconds.

[0022] Furthermore, the total deposition time for the dual-potential pulse electrodeposition described in step 3 is 10-20 minutes.

[0023] Furthermore, the detergent used for washing in step 4 is deionized water.

[0024] Furthermore, the vacuum drying in step 4 is carried out at a temperature of 40~60 ℃ for 8~12 hours.

[0025] Furthermore, the planar dimensions of the NiFe LDH nanosheets are 30 nm to 50 nm.

[0026] The present invention also provides the application of the self-supported NiFe LDH oxygen evolution electrode obtained by the low-temperature pulse electrodeposition method in the oxygen evolution reaction at the anode of alkaline water electrolysis or anion exchange membrane water electrolysis.

[0027] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0028] 1. The low-temperature pulse electrodeposition preparation method of self-supporting NiFe LDH oxygen evolution electrode proposed in this invention and its application, through the synergistic regulation strategy of low-temperature environment control and pulse electrodeposition, enables the catalyst to have both high electrochemical active area and high mechanical stability, thereby significantly improving the apparent current density of OER and long-term catalytic stability.

[0029] 2. Regarding the high electrochemical active area, this invention utilizes the periodic modulation of more negative and more positive potentials under a dual-potential pulse mode, which slows down the growth rate of already deposited crystal nuclei, alleviates the continuous overgrowth process of crystal nuclei in constant potential deposition, and increases the number of stable crystal nuclei formed per unit time, which is beneficial for forming a relatively dense deposition layer. Furthermore, by controlling the low temperature of the deposition solution, the diffusion coefficient and mobility of metal ions are significantly reduced, so that even if the species reduced to the electrode surface do not diffuse to the surface of existing crystal nuclei, they will combine with the nearest lattice position to generate new crystal nuclei, promoting the multiple nucleation process. Finally, under the low-temperature pulse electrodeposition conditions, a uniform and dense NiFe LDH catalyst layer composed of tightly packed fine nanosheet grains is formed, with its electrochemical active area increased by about 4 times compared to the electrode of constant potential deposition at room temperature. The apparent current density at the same potential is significantly improved, thereby improving the energy conversion efficiency of alkaline water electrolysis.

[0030] 3. Regarding high mechanical stability, the self-supporting NiFe LDH oxygen evolution electrode obtained by the low-temperature pulse electrodeposition method of this invention, on the one hand, increases the contact area and strengthens the bonding force between the catalyst layer and the conductive substrate due to the dense and uniform distribution of the catalyst layer. Simultaneously, the uniform stress distribution at the interface prevents further peeling and detachment of the catalyst layer when subjected to oxygen bubble erosion and the appearance of local small cracks due to uneven stress. On the other hand, the deposition kinetics of metal ions become slow and controllable under low-temperature conditions, resulting in more complete chemical bonding between the primary crystal nuclei and the substrate, which is conducive to the formation of stronger bonding effects, thereby greatly improving the mechanical stability of the electrode. Ultimately, in 1 M KOH electrolyte and 1 A cm⁻¹… -2 Stable operation for up to 1000 hours was achieved at current density. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 The images show the scanning electron microscope (SEM) morphology of the oxygen evolution electrodes obtained in Comparative Examples 1, 2, and 1; where a and b are SEM morphology images of Comparative Example 1 at scale bars of 3 μm and 1 μm, respectively; c and d are SEM morphology images of Comparative Example 2 at scale bars of 2 μm and 1 μm, respectively; and e and f are SEM morphology images of Example 1 at scale bars of 2 μm and 500 nm, respectively.

[0033] Figure 2 SEM images of the oxygen evolution electrodes obtained in Examples 2 and 3 are shown below; where a is the SEM image of Example 2 at a scale bar of 500 nm; and b is the SEM image of Example 3 at a scale bar of 200 nm.

[0034] Figure 3 Cyclic voltammetry (CV) curves of the oxygen evolution electrodes obtained in Comparative Example 1 and Example 1 at different scan rates are shown; where a is Comparative Example 1; b is Example 1.

[0035] Figure 4 The fitting results are for the electrochemical active area (ECSA) of the oxygen evolution electrodes obtained in Comparative Example 1 and Example 1;

[0036] Figure 5The fine X-ray photoelectron spectroscopy (XPS) spectra of Ni 2p and Fe 2p of the oxygen evolution electrodes obtained in Comparative Examples 1, 2, and 1 are shown; where a represents Ni 2p and b represents Fe 2p.

[0037] Figure 6 Linear sweep voltammetry (LSV) curves of the oxygen evolution electrodes obtained in Comparative Example 1, Comparative Example 2 and Example 1 in an H-type electrolytic cell and in 1 M KOH electrolyte;

[0038] Figure 7 The results show the electrochemical stability of the oxygen evolution electrodes obtained in Comparative Example 1, Comparative Example 2 and Example 1 in an H-type electrolytic cell, in 1 M KOH electrolyte, and at a current density of 1 A cm⁻².

[0039] Figure 8 The images show the SEM morphology of the oxygen evolution electrodes obtained in Comparative Examples 1, 2, and 1 after electrochemical stability testing; where a represents Comparative Example 1, b represents Comparative Example 2, and c represents Example 1. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0041] Example 1

[0042] This embodiment proposes a low-temperature pulse electrodeposition method for preparing a self-supporting NiFe LDH oxygen evolution electrode, including the following steps:

[0043] Step 1: Using nickel foam as a conductive substrate, cut the nickel foam into 1 cm × 2 cm sizes, and then ultrasonically clean it in sequence with 3 M HCl solution for 20 minutes, acetone for 5 minutes, ethanol for 5 minutes, and deionized water for 5 minutes to remove the surface oxide layer and oil stains. Then, vacuum dry it at 60 ℃ for 8 hours for later use.

[0044] Step 2: Add Ni(NO3)2•6H2O and FeSO4•7H2O to 40 mL of deionized water, where the concentration of Ni(NO3)2•6H2O is 0.12 M and the concentration of FeSO4•7H2O is 0.04 M, and add 4 mL of formamide to obtain the sedimentation solution.

[0045] Step 3: The pretreated nickel foam is used as the working electrode, the platinum sheet as the counter electrode, and the Hg / HgO electrode as the reference electrode, and placed in the deposition solution. The temperature of the deposition solution is controlled at 4 ± 1℃ by an ice bath. Pulse electrodeposition is performed by applying a dual-potential pulse mode to the working electrode: high potential (E1) is -0.8 V vs. Hg / HgO, low potential (E2) is -1.0 V vs. Hg / HgO, pulse duty cycle is 1:1, pulse period is 2 seconds, and the total deposition time is 15 minutes.

[0046] Step 4: After deposition, remove the working electrode, rinse it repeatedly with deionized water, and vacuum dry it at 60 °C for 8 hours to obtain a catalyst layer grown in situ on the surface of a conductive substrate, namely a formamide-intercalated NiFe LDH nanosheet array, which then forms a uniform and dense self-supporting NiFe LDH oxygen evolution electrode, denoted as LP-NiFe LDH.

[0047] Example 2

[0048] This embodiment proposes a low-temperature pulse electrodeposition method for preparing a self-supporting NiFe LDH oxygen evolution electrode. Compared with Example 1, the only difference is that the high potential of the pulse electrodeposition is changed from -0.8 V to -0.7 V, and the low potential is changed from -1.0 V to -0.9 V; all other conditions are exactly the same. The resulting self-supporting NiFe LDH oxygen evolution electrode is designated as LP-NiFe LDH-2.

[0049] Example 3

[0050] This embodiment proposes a low-temperature pulse electrodeposition method for preparing a self-supporting NiFe LDH oxygen evolution electrode. Compared with Example 1, the only difference is that the pulse duty cycle changes from 1:1 to 1:2; all other conditions are exactly the same. The resulting self-supporting NiFe LDH oxygen evolution electrode is denoted as LP-NiFe LDH-3.

[0051] Comparative Example 1

[0052] This comparative example presents a room-temperature constant-potential deposition method for preparing a self-supporting NiFe LDH oxygen evolution electrode. The only difference from Example 1 is that the temperature of the deposition solution is controlled at 25 °C, the electrodeposition mode is changed to constant-potential deposition with a constant potential of -0.90 V vs. Hg / HgO, and the deposition time is 15 minutes; all other conditions (deposition solution formulation and substrate pretreatment) are exactly the same. The resulting self-supporting NiFe LDH oxygen evolution electrode is denoted as NiFe LDH.

[0053] Comparative Example 2

[0054] This comparative example presents a room-temperature pulse electrodeposition method for preparing a self-supporting NiFe LDH oxygen evolution electrode. The only difference from Example 1 is that the temperature of the deposition solution is controlled at 25 °C; all other conditions are identical. The resulting self-supporting NiFeLDH oxygen evolution electrode is denoted as P-NiFe LDH.

[0055] Test Example 1

[0056] The morphology of the oxygen evolution electrodes obtained in Examples 1, 2, 3, Comparative Example 1, and Comparative Example 2 was observed using SEM, and the results are as follows: Figure 1 and Figure 2 As shown.

[0057] Figure 1 a and b are SEM images of Comparative Example 1 (NiFe LDH) at scale bars of 3 μm and 1 μm, respectively. It can be seen that the intercalated NiFe LDH prepared by room temperature constant potential deposition exhibits a typical three-dimensional porous network structure of ultrathin nanosheets. The open pores between the nanosheets are well developed, showing a relatively loose stacking morphology. This results in a relatively smaller contact area between the catalyst layer and the conductive substrate and a less firm bond.

[0058] Figure 1 c and d are SEM morphology images of Comparative Example 2 (P-NiFe LDH) at scale bars of 2 μm and 1 μm, respectively. It can be seen that the nanosheet array of the oxygen evolution electrode obtained by room temperature pulse electrodeposition is more uniform and dense than that of Comparative Example 1, with increased interlayer stacking and retention of some open pore structures.

[0059] Figure 1 e and f are SEM morphology images of Example 1 (LP-NiFe LDH) at scale bars of 2 μm and 500 nm, respectively. It can be seen that the microstructure of the oxygen evolution electrode obtained by low-temperature pulse electrodeposition has changed significantly. The electrode surface exhibits a dense, compact, and uniform cluster structure, in which the nanosheets are tightly stacked. The planar size of the nanosheets is 30 nm to 50 nm, and the gap between the layers is significantly reduced.

[0060] Figure 2 Image a is the SEM morphology of Example 2 (LP-NiFe LDH-2) at a scale bar of 500 nm. Figure 2Figure b shows the SEM morphology of Example (LP-NiFe LDH-3) 3 at a scale bar of 200 nm. As can be seen from the figure, the NiFe LDH prepared in both examples exhibits a dense and compact clustered nanosheet stacked structure, highly consistent with the morphological characteristics of Example 1 (LP-NiFe LDH). This indicates that fine-tuning the pulse electrodeposition parameters (such as pulse duty cycle and deposition potential) within a reasonable range does not disrupt the dominant control of morphology by the low-temperature pulse electrodeposition process. This demonstrates that the low-temperature pulse electrodeposition preparation method of the present invention has good parameter tolerance, which is beneficial for the reproducibility of synthesis in industrial production.

[0061] Test Example 2

[0062] Cyclic voltammetry was used to test CV curves at different scan rates in the non-Radida interval, and the electric double layer capacitance (Cdl) was calculated to evaluate the ECSA of the oxygen evolution electrodes obtained in Example 1 and Comparative Example 1. Figure 3 Figures a and b show the CV test curves of the oxygen evolution electrodes obtained in Comparative Example 1 and Example 1, respectively, at different scan rates. The scan potential range is 0.15~0.25 V vs. Hg / HgO, and the scan rate is 10~100 mV s. -1 . Figure 4 The ECSA fitting results for the oxygen evolution electrodes obtained in Comparative Example 1 and Example 1 show that their ECSAs are 1.56 mF cm⁻¹. -2 and 6.56 mF cm -2 This quantitatively demonstrates that low-temperature pulse deposition significantly increases the active area of ​​NiFe LDH.

[0063] Test Example 3

[0064] The chemical bonding strength of the oxygen evolution electrodes obtained in Comparative Example 1, Comparative Example 2, and Example 1 was evaluated using XPS testing. The structures are as follows: Figure 5 As shown, Figure 5 a represents Ni 2p and b represents Fe 2p. It can be seen that the characteristic peaks of Ni 2p and Fe 2p in Example 1 (LP-NiFe LDH) are shifted by about 0.4 eV and 0.8 eV towards the direction of higher binding energy, respectively, compared with Comparative Example 1 (NiFe LDH) and Comparative Example 2 (P-NiFe LDH). This indicates that the electron cloud density around Ni and Fe atoms in LP-NiFe LDH is lower and the covalentity of the metal-oxygen coordination bond is stronger. This means that the low-temperature pulse electrodeposition method enhances the cohesive strength of the catalyst layer and its interfacial bonding force with the conductive substrate.

[0065] Test Example 4

[0066] The alkaline OER performance of the oxygen evolution electrodes obtained in Comparative Example 1, Comparative Example 2 and Example 1 was evaluated in an H-type electrolytic cell. The cathode was a platinum sheet electrode and the anode was an oxygen evolution electrode. The electrolytes for both the cathode and anode were 1 M KOH and separated by an anion exchange membrane.

[0067] First, perform the LSV test, and the results are as follows: Figure 6 As shown, with the increase of anode potential, the current density of Example 1 (LP-NiFe LDH) at the same potential is significantly greater than that of Comparative Example 1 (NiFe LDH) and Comparative Example 2 (P-NiFeLDH), demonstrating superior apparent OER activity. For example, at a potential of 1.49 V vs. RHE, the OER current density of LP-NiFe LDH can reach 1 A cm⁻¹. -2 The current densities of NiFe LDH and P-NiFe LDH are only 443 mA cm⁻¹. -2 and 697 mA cm -2 Therefore, it can be seen that LP-NiFe LDH prepared by low-temperature pulse electrodeposition achieves a significant improvement in the apparent activity of alkaline OER due to its higher electrochemical active surface area.

[0068] Then, at 1 A cm -2 The electrochemical stability of NiFe LDH, P-NiFe LDH, and LP-NiFe LDH was tested at a current density of [value missing], and the results are as follows: Figure 7 As shown, LP-NiFe LDH can operate stably for 1000 hours, and the reaction potential remains relatively stable throughout the process; while NiFe LDH and P-NiFe LDH both exhibit drastic potential fluctuations during operation, with a sudden increase in potential around 200 hours, indicating irreversible degradation of activity.

[0069] Furthermore, the electrode morphology of NiFe LDH, P-NiFe LDH, and LP-NiFe LDH after stable operation was characterized by SEM, and the results are as follows: Figure 8 As shown, where, Figure 8In Figure a, Comparative Example 1 is shown; in Figure b, Comparative Example 2 is shown; and in Figure c, Example 1 is shown. It can be seen that the original three-dimensional porous structure of the NiFe LDH nanosheets was severely damaged after the stability test, and the catalyst layer detached from the conductive substrate. While P-NiFe LDH retained some nanosheet morphology features, the catalyst layer showed obvious edge lifting and cracking, exposing the conductive substrate. This indicates that NiFe LDH and P-NiFe LDH could not withstand the long-term scouring of oxygen bubbles under high current density, leading to peeling and detachment. In contrast, even after a long-term stability test of 1000 hours, the LP-NiFe LDH electrode surface maintained a dense nanosheet structure highly similar to that before the reaction, and no obvious catalyst layer lifting or peeling was observed; only slight cracks appeared. Therefore, LP-NiFe LDH prepared by low-temperature pulse electrodeposition achieves excellent OER mechanical stability due to its stronger bonding with the substrate.

[0070] It should be noted that this is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions, and improvements made by those skilled in the art within the scope of the technology disclosed in the present invention, and within the spirit and principles of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing a self-supporting NiFe LDH oxygen evolution electrode by low-temperature pulse electrodeposition, characterized in that, Includes the following steps: Step 1: Pre-treat the conductive substrate; Step 2: Prepare a precipitation solution containing nickel salt, ferrous salt and formamide; Step 3: Using a conductive substrate as the working electrode, perform dual-potential pulse electrodeposition in a deposition solution at 2~6 ℃; Step 4: After deposition, the material is washed and vacuum dried to obtain an array of NiFe LDH nanosheets grown in situ on the surface of a conductive substrate, forming a uniform and dense self-supporting NiFe LDH oxygen evolution electrode.

2. The method for preparing a self-supporting NiFe LDH oxygen evolution electrode by low-temperature pulse electrodeposition according to claim 1, characterized in that, The dual-potential pulse electrodeposition described in step 3 is performed in a three-electrode system, with Hg / HgO as the reference electrode and a graphite rod or platinum sheet as the counter electrode.

3. The method for preparing a self-supporting NiFe LDH oxygen evolution electrode by low-temperature pulse electrodeposition according to claim 2, characterized in that, The high potential of the dual-potential pulse electrodeposition is -0.7 to -0.9 V vs. Hg / HgO, and the low potential is -0.9 to -1.1 V vs. Hg / HgO, with a difference of 0.2 V between the high and low potentials.

4. The method for preparing a self-supporting NiFe LDH oxygen evolution electrode by low-temperature pulse electrodeposition according to claim 3, characterized in that, The pulse duty cycle of the dual-potential pulse electrodeposition is 1:2 to 2:1, and the pulse period is 1 to 10 seconds.

5. The method for preparing a self-supporting NiFe LDH oxygen evolution electrode by low-temperature pulse electrodeposition according to claim 4, characterized in that, The total deposition time for the dual-potential pulse electrodeposition described in step 3 is 10-20 minutes.

6. The method for preparing a self-supporting NiFe LDH oxygen evolution electrode by low-temperature pulse electrodeposition according to claim 1, characterized in that, The conductive substrate is any one of nickel foam, nickel mesh, nickel foil, carbon cloth, and carbon paper.

7. The method for preparing a self-supporting NiFe LDH oxygen evolution electrode by low-temperature pulse electrodeposition according to claim 6, characterized in that, The nickel salt in step 2 is at least one of nickel nitrate, nickel chloride, or nickel sulfate, and the concentration of Ni²⁺ in the deposition solution is 0.08~0.20 mol / L; the ferrous salt in step 2 is at least one of ferrous sulfate or ferrous chloride, and the concentration of Fe²⁺ in the deposition solution is 0.02~0.08 mol / L; the molar ratio of Ni²⁺ to Fe²⁺ in the deposition solution is 3:

1.

8. The method for preparing a self-supporting NiFe LDH oxygen evolution electrode by low-temperature pulse electrodeposition according to claim 7, characterized in that, The volume fraction of formamide in the sedimentation solution described in step 2 is 7% to 11%.

9. The method for preparing a self-supporting NiFe LDH oxygen evolution electrode by low-temperature pulse electrodeposition according to any one of claims 1 to 8, characterized in that, The planar dimensions of the NiFe LDH nanosheets are 30 nm to 50 nm.

10. The application of the self-supporting NiFe LDH oxygen evolution electrode prepared by the method according to any one of claims 1 to 8 in the oxygen evolution reaction at the anode of alkaline water electrolysis or anion exchange membrane water electrolysis.

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