Method for electrochemically regulating MoS2 structure through potassium and application

Abstract

The invention discloses a method for electrochemically regulating and controlling a MoS2 structure through potassium and application. According to the method, an integrated MoS2-based flexible self-supporting hydrogen evolution catalytic electrode is constructed by adopting an electrostatic spinning combined hydrothermal synthesis technology. The potassium ion battery is assembled by using the self-supporting electrode as a negative electrode, and the MoS2 is subjected to electrochemical intercalation structure regulation and control by using the operation environment of the potassium ion battery. The MoS2-based flexible electrode disclosed by the invention shows ideal super-hydrophilic property and super-hydrophobic property. Meanwhile, the electrode has excellent HER performance, the overpotential of the electrode in 0.5 M H2SO4 electrolyte under the current density of 10 mA cm < 2 > is only 51 mV, and the corresponding Tafel value is 77 mV dec1. And meanwhile, the amorphous MoS2 electrochemically regulated and controlled by potassium ions has more active sites, and can provide more excellent HER electro-catalytic performance. In addition, a parallel carbon layer on the outer surface of MoSx not only provides a faster electron transfer approach, but also constructs H adsorption and HER micro limited areas. The electrode obtained by electrochemically regulating and controlling the MoS2 structure through potassium has an extremely high electrochemical application prospect.

Description

Technical Field

[0001] This invention relates to the field of electrochemical regulation, and in particular to a method for regulating the structure of MoS2 (molybdenum disulfide) by electrochemical intercalation of potassium ions and its application in the electrocatalytic hydrogen evolution reaction. Background Technology

[0002] With the increasing global energy demand and the growing severity of environmental pollution, finding clean and efficient energy alternatives has become a crucial and urgent issue. Hydrogen energy, as an ideal clean energy source, has attracted significant attention due to its zero-carbon emission characteristic, with water as its only combustion product. Hydrogen evolution reaction (HER), a technology that electrochemically splits water into hydrogen and oxygen, is an effective way to achieve large-scale hydrogen production. However, currently widely used HER catalysts are mainly precious metals (such as platinum), whose high cost limits large-scale application. Therefore, developing efficient and low-cost electrocatalysts has become a current research hotspot.

[0003] Transition metal dichalcogenides (TMDs) are a class of materials that have attracted much attention due to their unique physical and chemical properties. These compounds have a layered structure, containing transition metals (such as molybdenum and tungsten) and chalcogen elements (such as sulfur and selenium), and have broad application prospects in electronics, optics, and catalysis. In the electrocatalytic hydrogen evolution reaction, TMDs are considered to be potentially highly efficient catalysts due to their abundant edge active sites and good stability. However, the interlayer stacking of TMDs and their inherently poor conductivity limit their catalytic performance. Molybdenum disulfide (MoS2), as a typical TMD, has been widely studied and applied due to its unique layered structure and abundant edge active sites. MoS2 has the advantages of abundant edge sites, low cost, and good chemical stability. However, MoS2 faces some challenges in practical applications, such as the reduction of effective active sites caused by interlayer stacking and its inherently poor conductivity. To overcome these problems, researchers have adopted various methods to regulate the structure and optimize the performance of MoS2. Among them, electrochemical intercalation technology has become an effective method for regulating the structure of layered materials due to its simple operation, mild conditions, and significant effects.

[0004] Electrochemical intercalation technology, by inserting ions into the interlayer spaces of layered materials, can effectively control the interlayer spacing and crystal structure, thereby improving their physicochemical properties. For example, alkali metal ions (such as lithium, sodium, and potassium), ammonium ions, and anions have been successfully used as intercalating agents to regulate the structure of materials such as graphene and tungsten disulfide (WS2), significantly improving their performance. Based on this background, this invention proposes a method for regulating the structure of MoS2 through potassium ion electrochemical intercalation to improve its performance in the electrocatalytic hydrogen evolution reaction.

[0005] This invention modulates the crystal structure of MoS2 through potassium ion electrochemical intercalation, increasing the interlayer spacing, exposing more active sites, and significantly improving the electrocatalytic hydrogen evolution performance of the MoS2-based electrode. Experimental results show that the modulated MoS2-based electrode exhibits excellent electrocatalytic hydrogen evolution performance in acidic electrolytes, with lower hydrogen evolution overpotential and higher catalytic efficiency. In summary, this invention effectively solves the problems of interlayer stacking and poor conductivity faced by MoS2 in the electrocatalytic hydrogen evolution reaction through innovative electrochemical intercalation modulation technology, significantly improving its electrocatalytic performance. This provides a new approach and method for developing efficient and low-cost electrocatalysts, and is of great significance for improving the efficiency of the electrocatalytic hydrogen evolution reaction. Summary of the Invention

[0006] To address the aforementioned problems, this invention aims to provide a method and application for potassium electrochemical regulation of MoS2 structure.

[0007] This invention aims to provide a method for regulating the structure of molybdenum disulfide (MoS2) through potassium ion electrochemical intercalation to improve its performance in the electrocatalytic hydrogen evolution reaction. This method utilizes potassium ions (K... + This invention possesses a large ionic radius and strong intercalation capability. Through electrochemical intercalation and deintercalation processes, it enables precise control over the interlayer spacing and structure of MoS2, thereby exposing more catalytically active sites, improving electron transport efficiency, and significantly enhancing its electrocatalytic hydrogen evolution performance. This invention has the advantages of simple operation, low cost, and significant effects, making it suitable for large-scale production.

[0008] The technical solution of this invention is a method and application of potassium electrochemical regulation of MoS2 structure, characterized in that the specific preparation steps are as follows: Step 1: Design and fabrication of MoS2-based self-supporting electrodes (1) Mix polyvinyl alcohol (PVA) and polytetrafluoroethylene (PTFE) and add them to deionized water, stir to obtain a homogeneous solution; (2) The solution from step (1) is electrospun under an electrostatic field to obtain PTFE / PVA nascent fibers; (3) The nascent fibers from step (2) are uniformly heated to 260°C for heat treatment to obtain a pre-oxidized CNF film; (4) The CNF film from step (3) is uniformly heated to 800°C under an inert gas atmosphere to carbonize it, thereby obtaining a pCNF film; (5) Add the CNF film from step (3) to (NH4)6Mo7O 24 • In an aqueous solution of 4H2 and CS(NH)2, until the color brightens; (6) The solution obtained in step (5) is transferred to a stainless steel reactor lined with PTFE and subjected to hydrothermal treatment to obtain MoS2@pCNF composite material; (7) Immerse the MoS2@pCNF composite material obtained in step (6) in Tris buffer, and add C8H 12 ClNO2 was added to the solution and stirred to obtain PDA@MoS2@pCNF precursor material; (8) The precursor material from step (7) is washed several times in deionized water and then dried; (9) The precursor material after step (8) is uniformly heated to 550°C under an inert gas atmosphere to obtain C@MoS2@pCNF film.

[0009] Step 2: Electrochemical intercalation to regulate the structure of MoS2 (1) Cut the C@MoS2@pCNF film from step one into small pieces and use them as cathodes. KFSI / EC and DMC are used as anodes and electrolytes, respectively. Assemble coin cells in a glove box filled with inert gas. (2) After the button cell of step (1) is charged and discharged in a constant current cycle within a certain potential range, the cathode is removed from the cell and washed in acetone, anhydrous ethanol and deionized water respectively, and the residual electrolyte is removed. (3) The cathode processed in step (2) is placed in a drying oven for drying to obtain C@MoS x @pCNF film.

[0010] Furthermore, in step one, the amount of polyvinyl alcohol used in the first sub-step is 1.412 g, the stirring temperature is 60 ℃, and the stirring time is 5 h; the amount of polytetrafluoroethylene used is 5.491 g, the stirring temperature is 60 ℃, and the stirring time is 12 h.

[0011] Furthermore, in step one, the electrostatic field in the second sub-step is 18 kV.

[0012] Furthermore, in step one, the heating rate in the third sub-step is 5 °C / min, and the heat treatment time is 2 h.

[0013] Furthermore, in step one, the second sub-step involves evacuating and introducing inert gas 3 to 5 times, for a duration of 5 to 10 minutes.

[0014] Furthermore, in step 4 of step one, the inert gas is Ar, the heating rate is 5 °C / min, and the carbonization time is 2 h.

[0015] Furthermore, the amount of CNF film sample added in step 5 of step one is 30 mg, (NH4)6Mo7O 24 The volume of the mixed aqueous solution of ·4H2O and CS(NH)2 is 10 mL, in which (NH4)6Mo7O 24 The mass of 4H2O is 60 mg, and the mass of CS(NH)2 is 1.5 g.

[0016] Furthermore, in step 6 of step one, the hydrothermal temperature is 220 ℃ and the hydrothermal time is 24 h.

[0017] Furthermore, in step 7 of step one, the volume of the Tris buffer is 100 mL, C8H 12 The amount of ClNO2 sample used was 200 mg, and the stirring time was 6 h.

[0018] Furthermore, in step one, the drying temperature in sub-step 8 is 60 ℃ and the drying time is 12 h.

[0019] Furthermore, in step 9 of step one, the inert gas is Ar, the heating rate is 5 ℃ / min, and the heat treatment time is 3.5 h.

[0020] Furthermore, in step two, the average areal density of the C@MoS2@pCNF film cut in the first sub-step is 1.5 mg / cm³. -2 .

[0021] Furthermore, in step two, the KFSI concentration in the first sub-step is 1.0 mol / L, the volume ratio of EC to DMC is 1:1, and the inert gas is Ar (H2O, O2<0.01 ppm).

[0022] Furthermore, in the second sub-step of step two, the sample is charged and discharged at 100 mA g. −1 At current density, the potential range is 0.01~3 V ( vs. K + / K), the cleaning time is 2 min.

[0023] Furthermore, the drying time in the third sub-step of step two is 5 minutes.

[0024] Furthermore, the potassium electrochemical intercalation-regulated MoS2-based self-supporting electrode can be applied in electrocatalytic hydrogen evolution.

[0025] Compared with the prior art, the beneficial effects of the present invention are reflected in: (1) The method of the present invention is simple to operate and can be carried out at room temperature and pressure, making it suitable for large-scale production. The electrochemical intercalation process is easy to control and can precisely regulate the interlayer spacing and structure of MoS2. Moreover, this method is not only applicable to the performance optimization of MoS2, but can also be extended to the electrochemical performance regulation of other layered materials, and has broad application prospects.

[0026] (2) The C@MoS2@pCNF thin film of the present invention has a layered nanostructure and exhibits excellent hydrophilic properties, which promotes the entry of electrolyte and mass transfer. The synergistic effect between the MoS2 edge sites and the carbon fiber skeleton significantly improves the activity of the catalyst. At the same time, the carbon layer on the outer surface of the MoS2 nanosheets also provides a faster electron transfer pathway for the composite material, exhibiting superior HER catalytic activity in the electrochemical hydrogen evolution reaction.

[0027] (3) C@MoS2 after potassium electrochemical regulation in this invention x The @pCNF self-supporting electrode not only exhibits ideal superhydrophilic and superhydrophobic properties, but also potassium ion electrochemically modulates α-MoS2. x It possesses more active sites. Based on C@MoS x The electrocatalytic hydrogen evolution reaction using a pCNF self-supporting electrode exhibits a hydrogen evolution overpotential of only 51 mV in 0.5 M H₂SO₄ electrolyte, corresponding to a Tafel value of only 77 mV. ‒1 It exhibits superior HER catalytic activity. Additionally, MoS2... x The parallel carbon layer on the outer surface provides a fast electron transfer pathway and also creates a micro-confined region that is different from the environment observed on the macroscopic surface. This provides sufficient space for H adsorption and also pushes H closer to the catalyst surface. Attached Figure Description

[0028] Figure 1 Flowchart for the design and fabrication of C@MoS2@pCNF flexible thin films; Figure 2 Photographs, flexible features, and SEM images of the pCNF thin film at different magnifications are provided. Figure 3 Photographs, flexible features, and SEM images of C@MoS2@pCNF films at different magnifications are provided for MoS2@pCNF films and C@MoS2@pCNF films. Figure 4 TEM images of C@MoS2@pCNF thin films at different magnifications; Figure 5 HRTEM images of the edges of MoS2 nanosheets at different magnifications; Figure 6A schematic diagram showing the assembly and disassembly of a potassium-ion button cell; Figure 7 C@MoS at different magnifications x SEM images of the @pCNF thin film; Figure 8 C@MoS at different magnifications x TEM images of the @pCNF thin film; Figure 9 For C@MoS x TEM images, HRTEM images, HAADF-STEM images, and corresponding elemental distribution images of the @pCNF thin film; Figure 10 pCNF, C@MoS2@pCNF, and C@MoS in Embodiment 7 of the present invention x Contact angle diagram of @pCNF; Figure 11 C@MoS in Embodiment 8 of the present invention x @pCNF bubble adhesion force performance diagram and bubble adhesion schematic diagram; Figure 12 pCNF, C@MoS2@pCNF, and C@MoS in Embodiment 10 of the present invention x Electrochemical hydrogen production performance of @pCNF. Detailed Implementation

[0029] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0030] 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 described herein.

[0031] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be readily apparent to those skilled in the art. This application specification and embodiments are merely exemplary.

[0032] The terms "contains," "includes," "has," and "contains" used in this article are all open-ended, meaning they include but are not limited to: Example 1: Design and fabrication process of a C@MoS2@pCNF flexible thin film Preparation process as follows Figure 1 As shown (1) Preparation of pCNF thin films by electrospinning Using polyvinyl alcohol (PVA) as the carbon matrix, it is mixed with polytetrafluoroethylene (PTFE) and PTFE / PVA nascent fibers are prepared by electrospinning the PTFE / PVA mixed solution. Then, pCNF membranes are prepared by pre-oxidation and carbonization.

[0033] (2) Preparation of MoS2@pCNF thin films by hydrothermal method (NH4)6Mo7O 24 MoS2 was grown in the pores of pCNF thin films using ×4H2O as the Mo source and CS(NH)2 as the S source via a hydrothermal method.

[0034] (3) Preparation of C@MoS2@pCNF thin films by polydopamine (PDA) coating method First, the MoS2@pCNF composite material was immersed in 100 mL of Tris buffer, and then 200 mg of C8H was added. 12 ClNO2 was added to the solution and stirred for 6 h to obtain PDA@MoS2@pCNF precursor material.

[0035] Example 2: Characterization of C@MoS2@pCNF flexible thin film material (1) X-ray diffraction analysis (XRD) The phase composition and crystal structure of the C@MoS2@pCNF flexible thin film were determined by X-ray diffraction (XRD). A Cu Kα radiation source was used, with a scanning range of 2q = 10–80°. The diffraction patterns were analyzed and compared with powder diffraction profile cards (PDF cards) to identify the phase composition of the material.

[0036] (2) Scanning electron microscopy (SEM) The surface microstructure of C@MoS2@pCNF flexible films was observed using scanning electron microscopy (SEM). A focused electron beam was used to scan the samples, collecting secondary electrons to form images. The microstructure, surface smoothness, and degree of aggregation of the samples were analyzed by examining the contrast of the images.

[0037] (3) Transmission electron microscopy (TEM) Transmission electron microscopy (TEM) is used to characterize the size, crystallinity, phase structure, and growth orientation of C@MoS2@pCNF flexible films. A high-voltage electron beam is transmitted through the sample, secondary electron signals are collected and converted into images, and a low accelerating voltage is used to avoid material damage, thus obtaining high-resolution structural information.

[0038] (4) Energy-dispersive X-ray spectroscopy (EDS) Energy-dispersive X-ray spectroscopy (EDS) was used to analyze the micro-region composition and content of the C@MoS2@pCNF flexible thin film. Combined with SEM, characteristic X-rays excited by the incident electron beam were collected to obtain the energy spectrum. Qualitative and quantitative analyses were performed using photon count rate and elemental energy values ​​to determine the material's compositional distribution.

[0039] (5) X-ray photoelectron spectroscopy (XPS) X-ray photoelectron spectroscopy (XPS) is used for elemental analysis of C@MoS2@pCNF flexible thin films. A high-energy electron beam bombards a target (such as Al or Mg), generating characteristic X-rays that irradiate the material, causing electrons within atoms to ionize and escape. These electrons are then collected and analyzed. The elemental types and contents are determined by the peak positions, intensities, and shifts of the photoelectron spectra. The analysis is performed using an Al Kα radiation source.

[0040] Example 3: Morphology and Structure Analysis of C@MoS2@pCNF Flexible Thin Film pCNF thin films were prepared by electrospinning technology, such as Figure 2 As shown in Figure a, in the spinning sol precursor, PVA and PTFE molecules crosslink through hydrogen bonding to form a stable PVA-PTFE sol. During oxidation at 260 °C, PVA dehydrogenates to form conjugated C=C bonds, enhancing fiber stability. Carbonization in a N2 atmosphere at 800 °C causes pyrolysis of the PTFE macromolecules, forming pores and yielding a pCNF film with a porous morphology. A bending force is applied to the pCNF film... Figure 2 (b) The film did not break upon release, demonstrating its flexibility. SEM observation revealed that the pCNF film exhibited a nanofiber structure with fiber thicknesses of approximately 220–230 nm. Figure 2 c and d). A comparison of carbon distribution regions and pore structures in SEM reveals that pores are distributed throughout the entire carbon nanofiber, possessing a porous interconnected structure capable of supporting catalytically active materials and providing a conductive network. Figure 2 e and f).

[0041] MoS2 nanosheets were grown on pCNF via a hydrothermal method, and a carbon layer was coated onto the MoS2 surface using a polydopamine carbon coating method to prepare an integrated C@MoS2@pCNF flexible film. Bending forces were applied to the MoS2@pCNF film and the C@MoS2@pCNF film. Figure 3 (a and b) did not break after release, demonstrating its flexibility. SEM tests showed that the individual fibers of the C@MoS2@pCNF film had a diameter of approximately 420~450 nm, loaded with a large number of MoS2 nanosheets, with almost no aggregation. Figure 3(c and d). The pCNF framework is uniformly dispersed and loaded with MoS2 nanosheets, reducing electron transport resistance loss and exposing more active sites. The precursor solution enters the macropores of the pCNF, and the MoS2 nanosheets nucleate and grow from the pores, becoming tightly fixed on the pCNF framework, enhancing the charge transfer process and protecting the MoS2 nanosheets.

[0042] TEM images show that ultrathin MoS2 nanosheets grow vertically on carbon nanofibers, with carbon layers covering the edges. Figure 4 (a and b). The carbon layer is formed by the self-polymerization of organic dopamine under weakly alkaline conditions, and graphitized carbon layer is formed after calcination and carbonization. The carbon layer and the pCNF framework work synergistically to improve the charge transfer rate. TEM observation shows that the lateral size of MoS2 nanosheets is approximately 100~200 nm. Figure 4 c and d).

[0043] HRTEM observations show that MoS2 has a layered structure with a discontinuous lattice, exhibiting abundant defects and creating more catalytically active sites. Figure 5 a). The (002) interplanar spacing of MoS2 is approximately 0.66 nm, which is 0.04 nm longer than that of 2H-MoS2, thus favoring the electrochemical behavior and H ingress and H2 exgress during the HER catalytic process. Figure 5 b).

[0044] Example 4: A C@MoS x Sample preparation method of @pCNF thin film Potassium electrochemical intercalation was regulated by assembling coin-type potassium-ion batteries. The prepared C@MoS2@pCNF films were cut into small pieces with an average areal density of approximately 1.5 mg / cm³. ‒2 The cathode was used as a cathode. A coin cell was assembled in a glove box filled with Ar gas (H2O, O2 < 0.01 ppm) using K foil and 1.0 M KFSI / EC:DMC (1:1, v / v) as the anode and electrolyte, respectively. Figure 6 As shown. At 100 mA g −1 At current densities of 0.01~3 V ( vs. K + A constant current charge-discharge cycle was performed within the potential range of / K to achieve potassium electrochemical regulation. After charge-discharge, the cathode was removed from the battery and washed for 2 min each in acetone, anhydrous ethanol, and deionized water to remove residual electrolyte. Finally, it was dried in a drying oven for 5 min to obtain C@MoS x @pCNF film.

[0045] Example 5: C@MoS x Morphology and structural analysis of pCNF thin films To understand the potash-treated C@MoS x The morphology of the @pCNF thin film was analyzed by SEM, and the results are as follows. Figure 7 As shown in the SEM image, C@MoS x The pCNF film still maintains a complete fiber network structure, indicating that the film structure was not damaged during potassium electrochemistry, demonstrating good stability. Figure 7 a and b). Compared to the original C@MoS2@pCNF film, the number of MoS2 sheets in the potassium-treated film is significantly reduced ( Figure 7 c). The fiber diameter in the region without nanosheets is larger than that of the pCNF film, and the fibers have a dense porous structure, exhibiting a particle aggregate morphology. Figure 7 d) This is because the MoS2 crystals are regulated to form amorphous α-MoS2 during the potassium electrochemical process. x Nanoparticles aggregate on the surface and in the pores of pCNF.

[0046] To further understand C@MoS x The structure of the @pCNF thin film was analyzed using TEM, and the results are as follows: Figure 8 As shown, the potassium-treated film retains its intact fibrous structure, with no obvious nanosheet structure observed. The fibers exhibit a porous structure, consistent with the SEM results. Figure 8 a). TEM testing of a single fiber revealed regions of particle aggregation, and a carbon layer remained on the outer surface of the fiber. Figure 8 (b) This demonstrates that the graphite network structure possesses both mechanical flexibility and electrochemical stability, maintaining structural stability during potassium electrochemistry and achieving confined potassium encapsulation of MoS2, thus transforming the loose α-MoS2... x Nanoparticles are bound to pCNF to prevent structural collapse and loss of MoS2.

[0047] Further analysis of potassic C@MoS2 after potassium treatment using HRTEM and elemental distribution images. x The microstructure of the @pCNF thin film, as shown in the results. Figure 9 As shown. The HRTEM image reveals a large-area amorphous structure, and the corresponding elemental distribution image indicates that Mo, S, and C elements are uniformly distributed (…). Figure 9 This confirms that amorphous MoS2 x The existence of.

[0048] Example 6: Potassium electrochemical intercalation to regulate the structure of MoS2 (1) Battery assembly: In an inert atmosphere glove box, a C@MoS2@pCNF thin film is used as the cathode, potassium foil as the anode, and glass fiber as the diaphragm.

[0049] Prepare the electrolyte: Dissolve 1M KPF6 in a mixed solvent of ethylene carbonate (EC) and diethyl carbonate (DEC) (1:1, volume ratio).

[0050] The above components are assembled into a button cell.

[0051] (2) Electrochemical intercalation: Potassium ion intercalation and deintercalation were performed using constant current charge-discharge cycling. Within a voltage range of 0.01–2.5 V, 50 charge-discharge cycles were conducted at a current density of 0.1 C to achieve potassium ion intercalation and deintercalation, thereby controlling the interlayer spacing and structure of MoS2 to achieve amorphous crystal formation and the formation of an integrated MoS2 crystal. x Self-supporting electrode.

[0052] Example 7: Contact angle testing of a material based on potassium electrochemical modulation of MoS2 structure Figure 10 pCNF, C@MoS2@pCNF, and C@MoS were displayed. x The contact angle of @pCNF was measured. Using electrospun pCNF films as a comparison, the contact angles of pCNF, C@MoS2@pCNF, and C@MoS2@pCNF were tested using the static contact angle method. x @Surface wettability of pCNF. When approximately 1 mL of deionized water is dropped onto each of the three surfaces, the contact angle of the droplet on the pCNF film surface is approximately 130°, indicating that it exhibits hydrophobic properties. Figure 10 a). In contrast, in the contact angle test of the C@MoS2@pCNF self-supporting electrode, the contact angle when the droplet just contacts the electrode surface is 40° ( Figure 10 b), and the potassium-treated C@MoS x In the contact angle test of the @pCNF self-supporting electrode, the droplet rapidly diffused and disappeared upon contact with the catalytic electrode surface, indicating that the C@MoS x @pCNF self-supporting electrodes have superhydrophilic properties ( Figure 10 c).

[0053] Example 8: Test of bubble adhesion force of a material based on potassium electrochemical regulation of MoS2 structure Figure 11 C@MoS was displayed x The change in bubble adhesion force of @pCNF was further investigated, and the potassium-treated C@MoS2 was further studied. x @pCNF self-supporting electrode surface wettability. Figure 11 a and 11b demonstrate C@MoS x @pCNF bubble adhesion test results and schematic diagram. C@MoS xIn the bubble adhesion force test of the @pCNF catalytic electrode, the lower half of the curve represents the process of bubbles approaching the electrode surface, and the upper half of the curve represents the process of bubbles gradually leaving the electrode surface. The inset shows optical images of the bubble state at the corresponding stages during the adhesion force test. Figure 11 a). C@MoS x The @pCNF electrode did not exhibit significant bubble adhesion, which facilitates bubble detachment. Ideal superhydrophilicity and surface air-repellency allow bubbles to rapidly detach from C@MoS₂. x @pCNF electrode surface release facilitates gas evolution reactions. This characteristic can be attributed to the nanoarray structure on the fiber surface causing a discontinuous state in the gas-liquid-solid three-phase contact line on the electrode surface. Figure 11 (b) This reduces the contact area between the bubbles and the sample surface, thereby decreasing the adhesion force of the electrode to the bubbles in the liquid medium. Superhydrophilicity promotes the wetting of the electrocatalyst and the aqueous electrolyte, while superhydrophobicity facilitates the rapid detachment of bubbles, which in turn promotes sufficient contact between the electrolyte and the electrocatalyst, thus enhancing charge transfer and mass transfer processes.

[0054] Example 9: Hydrogen evolution performance test of a material based on potassium electrochemical modulation of MoS2 structure at different pH values To further evaluate C@MoS2@pCNF and C@MoS x The HER stability of the @pCNF self-supported electrode was investigated, and its electrocatalytic hydrogen evolution performance in electrolytes with different pH values ​​was tested using cyclic voltammetry (CV) and linear sweep voltammetry (LSV). In acidic electrolyte (0.5 M H₂SO₄), C@MoS₂... x The @pCNF electrode exhibits a hydrogen evolution overpotential of 120 mV at a current density of -10 mA / cm², 150 mV in alkaline electrolyte (1 M KOH), and 180 mV in neutral electrolyte (0.1 M PBS). These results indicate that C@MoS x The @pCNF electrode exhibits good hydrogen evolution performance in electrolytes with different pH values, especially under acidic conditions.

[0055] Example 10: An application of electrochemical hydrogen production based on potassium electrochemical regulation of MoS2 structure Figure 12 C@MoS2@pCNF and C@MoS were displayed. x The electrocatalytic HER performance of @pCNF was tested using a three-electrode system. Based on this, we further analyzed the changes in the electrode hydrogen evolution mechanism before and after potassium ion electrochemical intercalation regulation. The C@MoS2@pCNF self-supporting electrode exhibited excellent hydrophilicity, such as... Figure 12 As shown in figure a, in 0.5 M H2SO4 electrolyte, 10 mA cm‒2 The hydrogen evolution overpotential at the current density is only 85 mV, corresponding to a Tafel value of 90 mV dec. ‒1 ( Figure 12 (b) exhibits excellent HER catalytic performance. The synergistic effect between the MoS2 edge sites and the carbon fiber framework significantly improves the catalyst activity. Simultaneously, the carbon layer on the outer surface of the MoS2 nanosheets provides a faster electron transfer pathway for the composite material. Potassium-modified C@MoS2... x The @pCNF electrode exhibits ideal superhydrophilicity and superhydrophobicity in 0.5 M H₂SO₄ electrolyte at 10 mA cm⁻¹. ‒2 The overpotential at the current density is only 51 mV, corresponding to a Tafel value of 77 mV dec. ‒1 ( Figure 12 (b) exhibits superior HER catalytic performance. Potassium-ion electrochemically regulated amorphous MoS2 possesses more active sites, providing superior HER electrocatalytic performance compared to crystalline MoS2. Furthermore, MoS... x The parallel carbon layer on the outer surface provides a faster electron transfer pathway and also creates a micro-confined region for H adsorption and HER.

[0056] The present invention has been described above by way of example. It should be noted that any simple modifications, alterations or other equivalent substitutions that can be made by those skilled in the art without creative effort without departing from the core of the present invention fall within the protection scope of the present invention.

Claims

1. A method and application for potassium electrochemical regulation of MoS2 structure, characterized in that, The method includes the following steps: (1) Mix polyvinyl alcohol (PVA) and polytetrafluoroethylene (PTFE) and add them to deionized water, then stir to obtain a homogeneous solution; (2) Electrospinning the solution from step (1) under an electrostatic field to obtain PTFE / PVA nascent fibers; (3) The nascent fibers from step (2) are uniformly heated to 260°C for heat treatment to obtain a pre-oxidized CNF film. (4) The CNF film from step (3) is uniformly heated to 800°C in an inert gas atmosphere to carbonize it and obtain a pCNF film. (5) Add the CNF film from step (4) to (NH4)6Mo7O 24 • In an aqueous solution of 4H2O and CS(NH)2, until the color brightens; (6) The solution obtained in step (5) is transferred to a stainless steel reactor lined with PTFE and subjected to hydrothermal reaction to obtain MoS2@pCNF composite material. (7) Immerse the MoS2@pCNF composite material obtained in step (6) in Tris buffer and add C8H 12 ClNO2 solution, stirred, to obtain PDA@MoS2@pCNF precursor material; (8) Wash the precursor material from step (7) several times in deionized water and then dry it; (9) The precursor material after step (8) is uniformly heated to 550°C in an inert gas atmosphere for heat treatment to obtain C@MoS2@pCNF film. (10) Cut the C@MoS2@pCNF film from step (9) into small pieces and use them as cathodes. K foil, KFSI / EC, and DMC are used as anodes and electrolytes, respectively. Assemble coin cells in a glove box filled with inert gas, perform constant current cyclic charging and discharging, clean and dry the cathode to obtain C@MoSx@pCNF film.

2. The method and application of potassium electrochemical regulation of MoS2 structure according to claim 1, characterized in that, In step (1), the amount of polyvinyl alcohol used is 1.412 g, the stirring temperature is 60 ℃, and the stirring time is 5 hours; the amount of polytetrafluoroethylene used is 5.491 g, the stirring temperature is 60 ℃, and the stirring time is 12 hours.

3. The method and application of potassium electrochemical regulation of MoS2 structure according to claim 1, characterized in that, The electrostatic field voltage in step (2) is 18 kV.

4. The method and application of potassium electrochemical regulation of MoS2 structure according to claim 1, characterized in that, The heating rate in step (3) is 5°C / minute, and the heat treatment time is 2 hours.

5. The method and application of potassium electrochemical regulation of MoS2 structure according to claim 1, characterized in that, The inert gas in step (4) is argon (Ar), the heating rate is 5℃ / minute, and the carbonization time is 2 hours.

6. The method and application of potassium electrochemical regulation of MoS2 structure according to claim 1, characterized in that, The CNF film added in step (5) has a mass of 30 mg and (NH4)6Mo7O 24 The volume of the mixed aqueous solution of ·4H2O and CS(NH)2 is 10 mL, in which (NH4)6Mo7O 24 The mass of 4H2O is 60 mg, and the mass of CS(NH)2 is 1.5 g.

7. The method and application of potassium electrochemical regulation of MoS2 structure according to claim 1, characterized in that, The hydrothermal reaction temperature in step (6) is 220°C, and the hydrothermal reaction time is 24 hours.

8. A method for potassium electrochemical regulation of MoS2 structure and its application according to claim 1, characterized in that, The volume of Tris buffer in step (7) is 100 mL, and the added C8H... 12 The mass of ClNO2 was 200 mg, and the stirring time was 6 hours.

9. The method and application of potassium electrochemical regulation of MoS2 structure according to claim 1, characterized in that, The drying temperature in step (8) is 60°C and the drying time is 12 hours.

10. The application of the potassium electrochemically intercalated MoS2-based flexible self-supporting catalytic electrode prepared by the method according to claims 1 to 9 in electrocatalytic hydrogen evolution.

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