A high-activity super-hydrophilic and gas-repellent electrode used in low-pressure environment, and a preparation method and application thereof

Abstract

This invention discloses a highly active superhydrophilic and gas-repellent electrode for use in low-pressure environments, its preparation method, and its application, relating to the field of electrocatalysis. The preparation method includes the following steps: after cleaning and drying nickel fiber felt, a three-electrode system is assembled; linear scanning is performed using cyclic voltammetry; the precursor is then cleaned and dried; scanning etching is performed using a femtosecond laser processing device with a scanning interval of 25-300 μm to form periodic nanoscale and / or microscale structures, thus preparing the electrode. This application utilizes femtosecond laser-induced hydrophilic micro / nano physical structures for surface reconstruction and seeks a balance between efficient mass transfer and high-activity sites by optimizing the scanning interval, thereby improving the catalytic activity of the OER reaction and its stability under high current density. It has significant advantages such as simple preparation process, high mechanical strength, and excellent mass transfer efficiency, which is beneficial for the stable operation of water electrolysis hydrogen production equipment in extreme environments of high altitude and low pressure.

Description

Technical Field

[0001] This invention relates to the field of electrocatalysis, and more particularly to a highly active superhydrophilic and gas-repellent electrode for use under low-pressure conditions, its preparation method, and its application. Background Technology

[0002] Electrolysis of water to produce hydrogen has become the mainstream technology for large-scale green hydrogen production due to its advantages of zero carbon emissions and high hydrogen purity. The oxygen evolution reaction (OER) at the anode is a crucial step in this process. In high-altitude areas, the low air pressure and thin air lead to a decrease in oxygen partial pressure, affecting the efficiency of the OER at the anode and resulting in lower overall electrolysis efficiency. On one hand, as an evolution reaction, the nucleation, growth, and desorption processes of bubbles in the OER significantly impact the overall reaction. Superhydrophilic / superhydrophobic electrode surfaces can rapidly wet the electrolyte, making it easier for reactants to contact the active sites and facilitating rapid desorption of bubbles from the electrode surface, thereby improving catalytic activity. Therefore, it is necessary to optimize the electrode's physical structure to improve its hydrophilicity / hydrophobicity and regulate the solid-liquid-gas three-phase mass transfer on the electrode surface. On the other hand, the chemical composition of the electrode determines the catalytic active sites and reaction energy barriers. Currently, nickel (Ni)-based electrodes are widely used as OER catalysts due to their low cost, abundant reserves, good alkalinity adaptability, and high catalytic performance. Their catalytic activity originates from the dynamically generated amorphous NiOOH phase on the surface, and this activity is mediated by… - The adsorption-desorption mechanism of the OOH intermediate enables efficient oxygen evolution.

[0003] Current techniques for preparing nickel-based alloy electrodes using electrodeposition coupled with high-temperature sintering suffer from drawbacks such as high energy consumption, poor pore structure uniformity, and low OER catalytic activity. Another approach involves fabricating self-supporting nickel-based electrodes based on a NiFe binary metal system using laser processing technology. Compared to traditional methods, this method is simpler to operate and allows for more precise control of active sites. However, this system, being based on a NiFe binary metal, while advantageous... While in-situ transformation and reduction of the activation energy barrier can be achieved, the potential for failure due to dynamic Fe dissolution remains. Traditional electrochemical methods can effectively activate Fe, but this process requires prolonged high-potential polarization, leading to a surge in energy consumption and a high risk of substrate structural collapse. Summary of the Invention

[0004] This invention provides a highly active superhydrophilic and gas-repellent electrode for use in low-pressure environments, its preparation method, and its application. By using femtosecond laser processing to precisely induce the formation of periodic micro-nano structures on the electrode substrate, it is possible to achieve rapid in-situ generation of highly active NiOOH and reduce the activation energy barrier, thereby improving the catalytic activity of OER. This achieves a three-dimensional synergistic improvement in mass transfer efficiency, mechanical strength, and catalytic activity, and solves the contradiction between the exposure of active sites and mass transfer efficiency in the electrode.

[0005] To address the aforementioned technical problems, one objective of this invention is to provide a method for preparing a highly active superhydrophilic and gas-repellent electrode under low-pressure conditions, comprising the following steps:

[0006] (1) Take nickel fiber felt for preliminary cleaning and drying. The thickness of the nickel fiber felt is 0.3-1.0 mm. Then, use it as a working electrode to assemble a three-electrode system. Use cyclic voltammetry to perform linear scanning. After processing, the nickel fiber felt is cleaned and dried a second time to obtain the precursor.

[0007] (2) The surface of the precursor is scanned and etched using a femtosecond laser processing device with a scanning interval of 25-300 μm to form a periodic nanoscale and / or microscale structure, thereby preparing the electrode.

[0008] This application employs linear scanning to pre-activate the nickel fiber felt, removing residual impurities and oxide layers from the electrode surface, preventing contact with the electrolyte, and stabilizing the electrode surface state to ensure chemical homogeneity. This effectively avoids uneven etching or energy dispersion issues during subsequent femtosecond laser processing. Subsequently, femtosecond laser processing is used to optimize the performance of the nickel fiber felt at both the physical structure and chemical composition levels. Physically, when the laser scanning interval is small, the material's specific surface area increases, leading to more active sites. However, the dense microgroove structure significantly increases electrolyte penetration resistance. Conversely, an excessively large scanning interval reduces the number of active sites. Therefore, controlling the scanning interval allows for a better balance between mass transfer rate and high-efficiency active sites, resulting in optimal catalytic efficiency. In terms of chemical composition, femtosecond lasers, with their ultrashort pulses, can instantly inject energy into the material surface. The incident laser interferes with the plasmon polaritons on the material surface, inducing the formation of a metastable NiO pre-oxidized layer. Coupled with the surface lattice distortion effect, this synergistically lowers the energy barrier of the NiO→Ni(OH)2→NiOOH phase transition in the OER reaction, enabling rapid in-situ generation of highly reactive NiOOH, reducing the reaction barrier of highly reactive NiOOH, and accelerating the process. - The adsorption-desorption process of OOH intermediates is beneficial to improving the catalytic activity of OER. Electrolyte convection is guided by a microgroove array, and periodic nanostripes expose more active phase, thus achieving both "highly active sites" and "efficient mass transfer pathways." Furthermore, this nickel fiber felt exhibits good conductivity and high mechanical strength, facilitating femtosecond laser processing and demonstrating potential for industrial applications at high current densities. It can adapt to high-altitude, low-pressure environments, improving the electrolysis efficiency of water electrolysis hydrogen production equipment.

[0009] In some embodiments, in step (1), the counter electrode in the three-electrode system is a platinum sheet, and the reference electrode is Hg / HgO.

[0010] In some embodiments, in step (1), the electrolyte in the three-electrode system is a KOH solution with a concentration of 0.5-2 mol / L.

[0011] In some implementations, in step (1), when linear scanning is performed using cyclic voltammetry, the scanning potential is 0.3 V-1 V vs. Hg / HgO, the scanning rate is 5-50 mV / s, and the number of scans is 20-30.

[0012] In some embodiments, in step (1), the initial cleaning is performed by sequentially cleaning with acetone, HCl solution and water, wherein the concentration of the HCl solution is 1-5 mol / L.

[0013] In some implementations, the secondary cleaning in step (1) is water cleaning.

[0014] In some embodiments, when scanning with a femtosecond laser processing device in step (2), the laser wavelength is 750-850 nm, the pulse width is 30-40 fs, the frequency is 1-2 kHz, the focal length is 95-105 mm, and the laser energy is 4×10⁻⁶. 4 -6×10 4 W / cm 2 The scanning speed is 4-6 mm / s.

[0015] In some implementations, when scanning with a femtosecond laser processing device in step (2), the scanning interval is 40-60 μm.

[0016] In some embodiments, in step (2), a femtosecond laser processing device is used to perform parallel line scanning etching, wherein the periodic nanoscale and / or microscale structure is nanoscale stripes and microscale grooves arranged at intervals, and the scanning interval is the center-to-center distance between adjacent scanning parallel lines.

[0017] To solve the above-mentioned technical problems, the second objective of this invention is to provide a highly active superhydrophilic and gas-repellent electrode for use in low-pressure environments, prepared by the above-mentioned method for preparing a highly active superhydrophilic and gas-repellent electrode for use in low-pressure environments.

[0018] To address the aforementioned technical problems, a third objective of this invention is to provide an application of a highly active, superhydrophilic, and gas-repellent electrode for hydrogen production via water electrolysis under low-pressure conditions.

[0019] In some embodiments, the highly active superhydrophilic and gas-repellent electrode for low-pressure environments serves as the anode for hydrogen production via water electrolysis.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] 1. This application achieves a balance between mass transfer rate and active sites by adjusting the scanning interval of femtosecond laser processing. This not only significantly increases the specific surface area of ​​the material and exposes more active sites, but also ensures a high mass transfer rate and improves the OER reaction catalytic activity of nickel-based electrode materials.

[0022] 2. This application achieves synergistic optimization through micron-level parallel linear grooves and periodic stripe grooves. The parallel linear grooves formed by femtosecond laser ablation can guide the flow of electrolyte in a directional manner, enhancing mass transfer efficiency. The periodic nanostripes formed on the material surface by laser-induced ablation are conducive to exposing more active sites, thereby achieving a leap in material performance. The micron-level grooves and nanostripes work together to form a hierarchical pore network, which dual-effectly enhances the catalytic effect.

[0023] 3. The femtosecond laser processing described in this application alters the hydrophilic / hydrophobic and gas-philic / hydrophobic properties of the nickel fiber felt surface. This is because the scanning interval of the laser processing affects the surface roughness of the material. With constant surface energy, the droplet contact angle is related to the surface roughness; the greater the roughness, the smaller the droplet contact angle, resulting in better hydrophilicity. This optimizes the three-phase interface and the bubble nucleation-growth-desorption process under low pressure. The synergistic effect of the micro / nano structure and the surface oxide layer significantly enhances the electrode's hydrophilicity. Simultaneously, through gas-phobicity control, the risk of electrolyte retention is effectively reduced, maintaining highly efficient and stable oxygen evolution reaction performance, especially in complex environments such as seawater electrolysis.

[0024] 4. The electrode preparation method of this application is simple to operate, energy-saving and efficient. The femtosecond laser adopts non-contact processing technology, which has short processing time and high precision, and does not require chemical etching and high temperature sintering, making it environmentally friendly.

[0025] 5. This application prepares a self-supporting electrode by integrally molding a three-dimensional nickel fiber felt substrate and a laser-induced multi-scale structure, which eliminates the need for binders or epitaxial growth, removes the risk of interface detachment, improves stability, and is suitable for actual industrial production.

[0026] 6. This invention achieves the construction of a highly active nickel-based OER electrode by optimizing the morphology and chemical composition of the Ni-based electrode, thus constructing a stable single-metal reinforcement system and avoiding the negative impact of Fe and Mo metal dissolution on system components (anion exchange membrane) caused by binary Ni-based alloys (such as NiMo, NiFe) during the OER process. Attached Figure Description

[0027] Figure 1 This is a partial flowchart illustrating a method for preparing a highly active superhydrophilic and gas-repellent electrode under low-pressure conditions, as described in an embodiment of the present invention.

[0028] Figure 2SEM images of the nickel-based electrodes in Example 1 and Comparative Example 1 of the present invention (Note: a - Comparative Example 1 with 500 nm resolution; b - Example 1 with 2 μm resolution; c - Example 1 with 500 nm resolution).

[0029] Figure 3 The image shows the Ni 2p peaks of the X-ray photoelectron spectroscopy spectra of the nickel-based electrodes in Embodiment 1 and Comparative Example 1 of this invention.

[0030] Figure 4 The O1s peak diagrams are shown for the X-ray photoelectron spectroscopy spectra of the nickel-based electrodes in Embodiment 1 and Comparative Example 1 of this invention.

[0031] Figure 5 The graph shows the test results of the droplet contact angle of the nickel-based electrode in Embodiment 1 and Comparative Example 1 of the present invention;

[0032] Figure 6 The image shows the Ni 2p peaks in the X-ray photoelectron spectra of the nickel-based electrodes before and after the OER reaction in Example 1 and Comparative Example 1 of this invention.

[0033] Figure 7 Linear voltammetry (LSV) curves of nickel-based electrodes in 1 mol / L KOH in Examples 1-5 and Comparative Example 1 of this invention.

[0034] Figure 8 Linear voltammetry (LSV) curves of nickel-based electrodes in 1 mol / L KOH in Example 1 and Comparative Examples 2-5 of this invention.

[0035] Figure 9 The double-layer capacitance (Cdl) obtained by testing the nickel-based electrode in Embodiment 1 and Comparative Examples 1-4 of the present invention after CV cycling under the non-Radida region.

[0036] Figure 10 The electrochemical impedance spectroscopy results are shown for the nickel-based electrodes in Examples 1-5 and Comparative Example 1 of this invention.

[0037] Figure 11 The electron paramagnetic resonance spectroscopy test results of the nickel-based electrodes in Example 1 and Comparative Example 1 of this invention;

[0038] Figure 12 The results are the in-situ Raman spectroscopy analysis of the nickel-based electrodes in Example 1 and Comparative Example 1 of this invention;

[0039] Figure 13 This is a 24-hour chronopotential curve of the nickel-based electrode after CP testing in Example 1 of the present invention. Detailed Implementation

[0040] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] 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. Any stated value or intermediate value within a stated range, as well as each smaller range between 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.

[0042] 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.

[0043] As used in this article:

[0044] In these embodiments, unless otherwise specified, the portions and percentages are all by weight.

[0045] "And / or" is used to indicate that one or both of the described situations may occur, for example, A and / or B includes (A and B) and (A or B).

[0046] In the description of this invention, it should be understood that the terms "upper", "lower", "left", "right", "top", "bottom", etc., indicating orientation or positional relationship are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0047] To further illustrate the present invention, the following detailed description is provided in conjunction with embodiments, but these should not be construed as limiting the scope of protection of the present invention. Unless otherwise specified, the raw materials used in the following embodiments and comparative examples are all commercially available, and the same raw materials were used in parallel experiments.

[0048] Example 1

[0049] A method for preparing a highly active superhydrophilic and gas-repellent electrode for use in low-pressure environments includes the following steps:

[0050] (1) Preparation of precursor: Take a nickel fiber felt with a thickness of 0.5 mm, and clean it by ultrasonication for 30 min each with acetone, 3 mol / L HCl solution and deionized water, then dry it in a nitrogen atmosphere and cut it into 1×1 cm size.

[0051] (2) Enhanced pre-activation treatment: The nickel fiber felt was used as the working electrode and placed in a standard three-electrode electrolytic cell. The counter electrode was a platinum sheet and the reference electrode was Hg / HgO. 1 mol / L KOH solution was used as the electrolyte. Cyclic voltammetry (CV) was used for linear scanning. The cyclic scanning potential was 0.3 V-1 V vs. Hg / HgO, the scanning rate was 10 mV / s, and the number of scanning cycles was 30 to pre-generate highly active substances on the surface. After the treatment, the nickel fiber felt was rinsed with deionized water and dried quickly to obtain the precursor.

[0052] (3) Femtosecond laser processing: such as Figure 1 As shown, parallel linear scanning was performed on a single surface of the nickel fiber felt precursor using a laser with a wavelength of 800 nm, a pulse width of 35 fs, a frequency of 1 kHz, a focal length of 100 mm, and a laser energy of 5 × 10⁻⁶. 4 W / cm 2 The scanning speed was 5 mm / s and the scanning spacing was 50 μm to etch periodic nanoscale stripes and microscale grooves on the surface of nickel fiber felt to prepare the electrode.

[0053] Example 2

[0054] A method for preparing a highly active superhydrophilic and gas-repellent electrode for use in a low-pressure environment. The steps, reagents, equipment and process parameters used in each step are the same as those in Example 1. The difference is that in step (3), the scanning distance during femtosecond laser processing is 25 μm.

[0055] Example 3

[0056] A method for preparing a highly active superhydrophilic and gas-repellent electrode for use in a low-pressure environment. The steps, reagents, equipment and process parameters used in each step are the same as those in Example 1. The difference is that in step (3), the scanning distance during femtosecond laser processing is 100 μm.

[0057] Example 4

[0058] A method for preparing a highly active superhydrophilic and gas-repellent electrode for use in a low-pressure environment. The steps, reagents, equipment and process parameters used in each step are the same as those in Example 1. The difference is that in step (3), the scanning distance during femtosecond laser processing is 200 μm.

[0059] Example 5

[0060] A method for preparing a highly active superhydrophilic and gas-repellent electrode for use in a low-pressure environment. The steps, reagents, equipment and process parameters used in each step are the same as those in Example 1. The difference is that in step (3), the scanning distance during femtosecond laser processing is 300 μm.

[0061] Comparative Example 1

[0062] A method for preparing an electrode includes the following steps:

[0063] (1) Preparation of precursor: Take a nickel fiber felt with a thickness of 0.5 mm, and clean it by ultrasonication for 30 min each with acetone, 3 mol / L HCl solution and deionized water, then dry it in a nitrogen atmosphere and cut it into 1×1 cm size.

[0064] (2) Enhanced pre-activation treatment: The nickel fiber felt was used as the working electrode and placed in a standard three-electrode electrolytic cell. The counter electrode was a platinum sheet and the reference electrode was Hg / HgO. 1 mol / L KOH solution was used as the electrolyte. Cyclic voltammetry (CV) was used for linear scanning. The cyclic scanning potential was 0.3 V-1 V vs. Hg / HgO, the scanning rate was 10 mV / s, and the number of scanning cycles was 30 to pre-generate highly active substances on the surface. After the treatment, the nickel fiber felt was rinsed with deionized water and dried quickly to prepare the electrode.

[0065] Comparative Example 2

[0066] A method for preparing an electrode includes the following steps:

[0067] (1) Preparation of precursor: Take a nickel fiber felt with a thickness of 0.5 mm, and clean it by ultrasonication for 30 min each with acetone, 3 mol / L HCl solution and deionized water, then dry it in a nitrogen atmosphere and cut it into 1×1 cm size to obtain the precursor.

[0068] (2) Femtosecond laser processing: A single-sided or double-sided parallel linear scan is performed on the surface of the nickel fiber felt precursor. The laser wavelength is 800 nm, the pulse width is 35 fs, the frequency is 1 kHz, the focal length is 100 mm, and the laser energy is 5 × 10⁻⁶. 4 W / cm 2The scanning speed was 5 mm / s and the scanning spacing was 50 μm to etch periodic nanoscale stripes and microscale grooves on the surface of nickel fiber felt to prepare the electrode.

[0069] Comparative Example 3

[0070] An electrode preparation method is provided, and the steps, reagents, equipment and process parameters used in each step are the same as those in Example 1. The difference is that in step (1), the thickness of the nickel fiber felt is 1 mm.

[0071] Comparative Example 4

[0072] An electrode preparation method is provided, and the steps, reagents, equipment and process parameters used in each step are the same as those in Example 1. The difference is that in step (1), the thickness of the nickel fiber felt is 0.3 mm.

[0073] Comparative Example 5

[0074] An electrode preparation method is provided, and the steps, reagents, equipment and process parameters used in each step are the same as those in Example 1. The difference is that in step (1), nickel fiber felt is replaced by nickel iron fiber felt of the same size.

[0075] Performance testing methods

[0076] 1. The electrodes prepared in Example 1 and Comparative Example 1 were observed on their surfaces using a scanning electron microscope. The SEM image of the electrode in Comparative Example 1 is shown below. Figure 2 As shown in Figure a, it can be seen that the surface of the electrode material in Comparative Example 1 is relatively smooth and does not have significant micro or nano structures. Figure 2 Figure b shows the SEM image of the electrode of Example 1. Compared with Comparative Example 1, the electrode material of Example 1 exhibits periodic nanoscale stripes and micrometer-scale trenches on its surface. This phenomenon can be attributed to the interaction between the ultrashort pulses of femtosecond laser processing and the material. When the laser energy is near the ablation threshold, the incident laser interferes with the plasmons on the material surface, inducing periodic rearrangement of atoms on the material surface, forming a nanoscale periodic stripe structure. The formation of nanoscale stripes effectively increases the surface roughness of the material, thereby increasing the electrochemically active area.

[0077] 2. The electrodes prepared in Example 1 and Comparative Example 1 were detected using X-ray photoelectron spectroscopy. Figure 3 The XPS plots of Ni 2p in Example 1 and Comparative Example 1 show that Ni 2p in Example 1 exhibits multiple splitting peaks, indicating a NiO structure. However, Ni 2p in Comparative Example 1 does not show multiple splitting, exhibiting a Ni(OH)2 structure. This is because NiO has a cubic rock salt structure (O... 2-Octahedral coordination), a strong crystal field leads to the splitting of d orbital energy levels, and the exchange interaction of unpaired electrons further exacerbates the multipeak splitting. Ni(OH)₂ has a hexagonal layered structure (…). - (OH octahedral coordination) and the low-symmetry coordination environment lead to a different d-orbital energy level splitting mode compared to NiO, which suppresses the formation of multiple peaks.

[0078] Figure 4 The XPS spectra of O1s in Example 1 and Comparative Example 1 show that Example 1 exhibits NiO lattice oxygen (O) at a binding energy of ~530 eV. 2- The significant characteristic peak of ) is observed in Comparative Example 1, while at ~532 eV, it mainly exhibits the hydroxyl oxygen of Ni(OH)2 () - OH) peak.

[0079] pass Figure 3-4 The results confirm that after femtosecond laser processing, the nickel-based electrode material was transformed from Ni(OH)2 to NiO. Combined with the laser processing conditions in Example 1, it can be inferred that the instantaneous high-temperature effect generated by the femtosecond laser induced the dehydration reaction of Ni(OH)2. This leads to the formation of oxide phases on the surface of nickel fiber felt.

[0080] Figure 5 The figures show the droplet contact angle test results for Example 1 and Comparative Example 1. It can be seen that the water contact angle in Example 1 is 172.2°, close to 180°, almost completely wetting the electrode surface, consistent with the superhydrophilic model. Conversely, the water contact angle in Comparative Example 1 is 56.2°, exhibiting superhydrophobic characteristics. This demonstrates that the preparation method of this invention achieves superhydrophilic / superhydrophobic electrodes, controlling the wettability of the electrode surface and laying the foundation for improving the performance of the subsequent oxygen evolution reaction.

[0081] 3. To investigate the practical application effect of nickel-based electrodes in the OER reaction, the electrodes prepared in Examples 1-5 and Comparative Examples 1-5 were tested for oxygen evolution reaction (OER) performance. The application method was as follows: the OER electrochemical performance of the materials was evaluated using a three-electrode system connected to a CHI1140E electrochemical workstation. The electrodes (1 cm × 1 cm) prepared in Examples 1-5 and Comparative Example 1, graphite rods, and Hg / HgO were used as working electrodes, counter electrodes, and reference electrodes, respectively. The catalytic performance of the materials was tested by linear voltammetry (LSV). The LSV test conditions were: at room temperature, in 1 mol / L KOH solution, at a scan rate of 5 mV / s. All LSV reactions were corrected by 80% iR compensation. The measured potential of OER was converted to a reversible hydrogen electrode (RHE) according to the following equation: E( vs. RHE)=E( vs.(Hg / HgO) + 0.098 + 0.059 × pH, the Ni 2p XPS spectrum tested in Example 1 is as follows. Figure 5 As shown, the OER polarization curves of Examples 1-5 and Comparative Examples 1-5 are as follows. Figure 6-7 The overpotentials under different current densities are shown in Table 1 below.

[0082] like Figure 6 As shown, in a 1 mol / L KOH electrolyte environment, the Ni 2p XPS spectrum tested after the OER reaction in Example 1 shows that Ni 2+ The characteristic peak (~854 eV) shifts towards the direction of higher binding energy and binds with Ni. 3+ The significant change in the intensity of the characteristic peak (~856 eV) confirms that NiO is transformed into the highly catalytically active NiOOH phase (NiO + OH) during electrochemical activation. - →NiOOH + e - Since NiOOH is an active intermediate in the OER reaction, its in-situ formation effectively lowers the oxygen adsorption energy barrier, thereby increasing the OER reaction rate. This result indicates that the NiO phase formed by laser processing dynamically reconstructs into active species during electrolysis, providing a clear phase evolution path for electrode performance optimization. Figure 7 The OER polarization curves of Examples 1-5 and Comparative Example 1 in 1 mol / L KOH electrolytic solution show that the OER catalytic performance of the electrode in Example 1 is improved, and the electrode material at 1 A / cm -2 At a current density of 1.65 V, the overpotential after conversion is only 420 mV, significantly lower than the 668 mV of Comparative Example 1, demonstrating highly efficient OER catalytic activity under industrial-grade high current density. This shows that the synergistic induction of periodic nanostripes by the micron-sized stripes in Examples 1-5 can significantly improve the material surface morphology and enhance OER catalytic performance. Furthermore, compared to Examples 2-5, Example 1, with a laser scanning spacing of 50 mm, exhibits the lowest overpotential and highest catalytic efficiency at a higher current density.

[0083] Figure 8The OER polarization curves of Example 1 and Comparative Examples 2-5 in 1 mol / L KOH electrolytic solution are shown. Compared with Comparative Example 25, Example 1 exhibits the highest current density and the best oxygen evolution reaction catalytic performance under the same voltage. Comparing Example 1 and Comparative Example 2 under controlled experimental variables, it can be seen that when the nickel fiber felt substrate thickness is 0.5 mm, the enhanced pre-activated nickel fiber felt substrate in Example 1 effectively improves the precursor catalytic activity. Furthermore, comparing Example 1 and Comparative Examples 3-5, which also underwent pre-activation treatment before femtosecond laser processing, the catalytic performance was optimal when the nickel fiber felt thickness was 0.5 mm. Based on the above analysis, the electrode from Example 1 was selected for subsequent femtosecond laser processing.

[0084] 4. Assemble a three-electrode system using the electrodes prepared in Examples 1-5 and Comparative Examples 1-5 (nickel-based electrode, graphite rod, and Hg / HgO were used as the working electrode, counter electrode, and reference electrode, respectively; 1 mol / L KOH solution was used as the electrolyte). To quantify the difference in active site density between this example and the comparative examples, cyclic voltammetry (CV) was used to scan within the non-Radial potential window. The test voltage range was selected as 1.0-1.1V (vs. RHE), the scan rate was 20mV / s-100mV / s, and data was extracted every 20 mV / s as a test interval. The number of scans was 200, and the double-layer capacitance (C) was calculated. dl The test results are as follows: Figure 9 As shown in Table 1, C dl The greater the slope of the line, the larger the electrochemically active area on the material surface.

[0085] Figure 9 The double-layer capacitance diagrams (C) obtained after CV cycling tests for Examples 1-5 and Comparative Example 1 are shown. dl In the embodiment, the double-layer capacitance Cdl is distributed at 4-12 mF / cm. 2 Comparative Example 1, C dl Only 0.48 mF / cm 2 The difference is significantly lower than that of the electrodes in the example. Furthermore, when the laser scanning spacing D in Example 2 is 25 mm, the sample exhibits the maximum C. dl It is 11.85 mF / cm 2 This indicates that the electrochemical active area is maximized under these conditions, directly verifying the significant enhancement effect of micro / nano structure formation on the exposure of active sites.

[0086] 5. Assemble a three-electrode system using the electrodes from Examples 1-5 and Comparative Example 1 (the electrodes from the examples or comparative examples, the graphite rod, and Hg / HgO were used as the working electrode, counter electrode, and reference electrode, respectively, and a 1 mol / L KOH solution was used as the electrolyte), measure the open-circuit voltage, and then at 10... -2-10 5 Electrochemical impedance spectroscopy (EIS) was acquired in the Hz frequency range to obtain the Nyquist plot, as shown below. Figure 10 As shown in the figure, the real part of the impedance corresponding to the middle of the semicircle represents the charge transfer resistance; a smaller charge transfer resistance corresponds to a faster electron transfer rate. The charge transfer resistance R of the nickel-based electrode prepared in Examples 1-5 is shown. t The charge transfer resistance (R) is distributed in the range of 1.3-2.5 Ω, significantly lower than that of the nickel-based electrode prepared in Comparative Example 1. Furthermore, in Example 1, when the scanning spacing D is 50 mm, the charge transfer resistance R... t The minimum value of 1.3 Ω indicates that the electrode of Example 1 has the fastest electron transfer rate and the highest OER catalytic activity.

[0087] Table 1 - Results of LSV, CV, and EIS tests on electrodes of the embodiments and comparative examples of this application.

[0088]

[0089] Based on the above analysis, through Figure 6-9 The results show that Example 2 (scanning distance D = 25 mm) has the largest electrochemical active area, while Example 1 (scanning distance D = 50 mm) exhibits the highest catalytic activity at industrial-grade high current densities. The two are not entirely consistent because while a smaller scanning distance increases the electrochemical active area of ​​the electrode, it hinders electrolyte flow and reactant diffusion, thus reducing mass transfer efficiency. However, if the scanning distance is too large, insufficient exposure of active sites also affects catalytic activity. Therefore, the optimal scanning distance in Example 1 achieves a better balance between mass transfer rate and highly efficient active sites, resulting in the best catalytic efficiency.

[0090] In Comparative Example 5, the nickel-iron fiber felt used to improve electrode activity in the short term due to the introduction of Fe. However, in long-term operation and in the high-potential (typically >1.4 V vs. RHE) and strongly alkaline (KOH solution) environment of the OER reaction, the Fe component in the NiFe alloy is in a less stable thermodynamic state compared to Ni. The dissolution potential of Fe is lower than that of Ni. Therefore, under anodic polarization conditions, Fe atoms are preferentially oxidized to Fe2+. 3+ or FeO4 2- Soluble ions are released and detach from the alloy lattice. Due to the dissolution of Fe elements and the failure of surface reconstruction, both catalytic efficiency and stability will decrease.

[0091] 6. Electron paramagnetic resonance (EPR) tests and in-situ Raman spectroscopy analyses were performed on the electrodes prepared in Example 1 and Comparative Example 1. The EPR spectra of Example 1 and Comparative Example 1 are as follows: Figure 11As shown, Example 1 exhibits a significant characteristic peak at g=2.0035, corresponding to the signal of a single-electron-occupied oxygen vacancy (VO); while Comparative Example 1 did not observe a significant characteristic peak at the same position. This result confirms that femtosecond laser processing in Example 1 successfully induced high-density oxygen vacancy formation on the nickel-based electrode surface, triggering surface reconstruction. In-situ Raman spectroscopy analyses of Example 1 and Comparative Example 1 are as follows: Figure 12 As shown, Example 1 exhibits a characteristic peak transition at 1.30 V vs. RHE potential, at 445 cm⁻¹. -1 (Ni) 2+ -OH) and 500 cm -1 (Ni) 2+ -O) vibration peak gradually disappears, while 475 cm -1 (Ni) 3+ -OH) and 550 cm -1 (Ni) 3+ The significantly enhanced characteristic peak (-O) indicates that the NiOOH active phase is generated in situ at this voltage. This phenomenon is observed in Comparative Example 1 (requires 1.45 V). vs The characteristic peak transition (occurring 150 mV earlier than expected at RHE potential) directly confirms that oxygen vacancies reduce OH-. - Adsorption and conversion accelerate the formation of highly active *OOH intermediates, effectively weakening the NiO→NiOOH phase transition energy barrier, thereby increasing the OER reaction rate.

[0092] 7. To verify the industrial application potential of the electrode material of this application under high current density, a three-electrode system was selected, with the electrode of Example 1, Hg / HgO, and the stone rod serving as the working electrode, reference electrode, and counter electrode, respectively, at 1 A / cm. -2 Potential constant (CP) tests were performed at high current densities to verify the OER stability of the material under high current density conditions. Figure 13 Example 1 at 1 A / cm -2 Chronopotential curves were obtained under a constant current density for 24 hours. The results show that the electrode material prepared in Example 1 maintains a relatively constant potential within 24 hours, exhibiting strong stability and potential for industrial application.

[0093] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. In particular, it should be noted that any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention for those skilled in the art.

Claims

1. A method for preparing a highly active superhydrophilic and gas-phobic electrode for use in low-pressure environments, characterized in that, Includes the following steps: (1) Take nickel fiber felt for preliminary cleaning and drying. The thickness of the nickel fiber felt is 0.3-1.0 mm. Then, use it as a working electrode to assemble a three-electrode system. Use cyclic voltammetry to perform linear scanning. After processing, the nickel fiber felt is cleaned and dried a second time to obtain the precursor. (2) The surface of the precursor is scanned and etched using a femtosecond laser processing device with a scanning interval of 25-300 μm to form a periodic nanoscale and / or microscale structure, thereby preparing the electrode; In step (1), when linear scanning is performed using cyclic voltammetry, the scanning potential is 0.3 V-1 V vs. Hg / HgO, the scanning rate is 5-50 mV / s, and the number of scans is 20-30.

2. The method for preparing a highly active superhydrophilic and gas-repellent electrode under low pressure environment as described in claim 1, characterized in that, In step (1), the counter electrode in the three-electrode system is a platinum sheet, and the reference electrode is Hg / HgO; And / or, in step (1), the electrolyte in the three-electrode system is a KOH solution with a concentration of 0.5-2 mol / L.

3. The method for preparing a highly active superhydrophilic and gas-phobic electrode under low pressure environment as described in claim 1, characterized in that, In step (1), the initial cleaning is performed by sequentially cleaning with acetone, HCl solution and water, wherein the concentration of the HCl solution is 1-5 mol / L; Alternatively, in step (1), the secondary cleaning is performed using water.

4. The method for preparing a highly active superhydrophilic and gas-repellent electrode under low pressure environment as described in claim 1, characterized in that, In step (2), when scanning with a femtosecond laser processing device, the laser wavelength is 750-850 nm, the pulse width is 30-40 fs, the frequency is 1-2 kHz, the focal length is 95-105 mm, and the laser energy is 4×10⁻⁶. 4 -6×10 4 W / cm 2 The scanning speed is 4-6 mm / s.

5. The method for preparing a highly active superhydrophilic and gas-phobic electrode under low pressure environment as described in claim 1, characterized in that, In step (2), when scanning with a femtosecond laser processing device, the scanning interval is 40-60 μm.

6. The method for preparing a highly active superhydrophilic and gas-phobic electrode under low pressure environment as described in claim 1, characterized in that, In step (2), a femtosecond laser processing device is used to perform parallel linear scanning etching, and the periodic nanoscale and / or microscale structure consists of nanoscale stripes and microscale trenches arranged at intervals.

7. A highly active superhydrophilic and gas-repellent electrode for low-pressure environments, prepared by the preparation method of the highly active superhydrophilic and gas-repellent electrode for low-pressure environments as described in any one of claims 1-6.

8. The application of the highly active superhydrophilic and gas-repellent electrode as described in claim 7 in the field of water electrolysis for hydrogen production under low pressure.

9. The application of the highly active superhydrophilic and gas-phobic electrode under low pressure environment as described in claim 8 in the field of hydrogen production by water electrolysis, characterized in that, The highly active, superhydrophilic, and gas-repellent electrode used in low-pressure environments serves as the anode for hydrogen production via water electrolysis.

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