A self-supporting catalytic electrode based on porous WB / WC composite ceramic membrane and a preparation method thereof

Abstract

This invention discloses a self-supporting catalytic electrode based on a porous WB / WC composite ceramic membrane and its preparation method. By employing phase transformation casting combined with BN powder embedding and sintering processes, a WB / WC heterojunction with nanogrooves and oriented straight pores is constructed in situ. This effectively increases active sites, optimizes interfacial mass transfer, improves electrocatalytic kinetics, and significantly enhances the electrode's catalytic performance. This invention combines phase transformation casting, powder embedding and sintering, and in-situ reaction techniques to prepare a ceramic membrane catalytic electrode with excellent performance in catalytic fields such as hydrogen evolution in water electrolysis, oxygen evolution in water electrolysis, carbon dioxide reduction, urea electrooxidation, methanol electrooxidation, and alkane dehydrogenation. The preparation process is simple, low-cost, and suitable for large-scale industrial production.

Description

Technical Field

[0001] This invention relates to a self-supporting catalytic electrode based on a porous WB / WC composite ceramic membrane and its preparation method, belonging to the field of new energy material preparation technology. Background Technology

[0002] With the increasing depletion of fossil fuel resources and the growing prominence of global climate and environmental problems, developing clean and sustainable new energy alternative technologies is a crucial direction for optimizing the energy structure at this stage. Hydrogen, as a clean and efficient energy carrier, can effectively store and convert renewable energy, and has significant application value in the transformation and upgrading of the global energy system. Proton exchange membrane electrolyzer technology is currently the mainstream solution for large-scale, high-efficiency water electrolysis; however, it relies on precious metal-based electrocatalysts such as platinum, iridium, and ruthenium, which are costly and scarce. Furthermore, traditional coated catalytic electrodes suffer from problems such as covered active sites, low charge transport rates, easy catalyst detachment, and poor mechanical stability, hindering the large-scale commercial application of this technology. Water electrolysis technology urgently needs low-cost, highly active, and highly stable non-precious metal self-supporting electrocatalytic materials to overcome the bottlenecks in large-scale application. Electrocatalytic CO2 reduction technology can utilize renewable electricity to convert greenhouse gases into high-value-added chemicals, offering the dual advantages of storing renewable energy and reducing atmospheric CO2 concentration, making it an advanced energy conversion and storage pathway. Furthermore, while electrocatalytic technologies such as methanol electro-oxidation, urea electro-oxidation, and alkane catalytic dehydrogenation are still under development, they hold promising future applications. Therefore, developing novel non-precious metal catalysts that are low-cost, highly active, and highly stable is crucial for overcoming existing energy conversion technology bottlenecks and promoting industrial application.

[0003] WC possesses a similar number of valence electrons and Fermi level electronic state density to Pt, exhibiting platinum-like electronic structure characteristics. It boasts excellent conductivity, good mechanical stability, and abundant surface active sites, making it suitable for demanding operating conditions and a high-performance non-precious metal-based catalytic material. Meanwhile, tungsten borides are abundant in the Earth's crust, have low raw material costs, and possess high hardness, high melting point, excellent chemical stability, and good electrical and thermal conductivity. Due to their excellent electrocatalytic activity, high current density adaptability, and long-term service stability, they show promising application prospects in water electrolysis for hydrogen and oxygen production. However, current technologies lack mature processes for the large-scale, low-cost preparation of WB / WC composite catalytic electrodes, making it difficult to obtain WB / WC composite catalysts that combine high hydrogen evolution catalytic activity, strong corrosion resistance, and stable structural characteristics. Summary of the Invention

[0004] This invention aims to propose a self-supporting catalytic electrode based on a porous WB / WC composite ceramic membrane and its preparation method. The method first prepares a porous WC / WS2 ceramic membrane green body by phase transformation casting, and then achieves in-situ reaction by embedding BN powder and sintering, thus obtaining a WB / WC heterojunction ceramic membrane self-supporting catalytic electrode with both nanogroove structure and oriented finger-shaped straight pore structure.

[0005] To achieve its objectives, the present invention employs the following technical solution: A method for preparing a self-supporting catalytic electrode based on a porous WB / WC composite ceramic membrane includes the following steps: (1) Tungsten carbide and tungsten disulfide powders are ball-milled and mixed with solvent, dispersant and binder to obtain a uniform ceramic slurry; (2) The ceramic slurry is degassed, cast, phase-transformed and cured, and then naturally dried to obtain a WC / WS2 ceramic film green body; (3) Cut the ceramic film blank to the required size; (4) The cut ceramic film green body is embedded in BN powder for pressureless sintering. During the powder embedding and sintering process, WB / WC heterostructure is generated in situ on the WC / WS2 ceramic film, thus obtaining a self-supporting catalytic electrode based on porous WB / WC composite ceramic film.

[0006] Furthermore, in step (1), the particle size of the tungsten carbide and tungsten disulfide powders is 1~10 μm.

[0007] Furthermore, in step (1), the mass ratio of the tungsten carbide and tungsten disulfide powders is 9:1 to 6:4.

[0008] Further, in step (1), the solvent is at least one of N-methylpyrrolidone and methyl ethyl ketone, the dispersant is at least one of KD-1 dispersant, polyvinylpyrrolidone and O-(2-aminopropyl)-O′-(2-methoxyethyl)polypropylene glycol, and the binder is at least one of polyvinyl alcohol, polyvinyl butyral and polyethersulfone.

[0009] Furthermore, in step (1), the rotational speed of the ball mill is 200~300 r·min. -1 The ball milling time is 24~50 h.

[0010] Further, in step (2), the ceramic slurry is first degassed for 0.5~1 h, then poured into the mold groove, and the height of the casting scraper is adjusted to 0.5~1.1 mm, and the casting speed is 20~100 cm·min. -1 After casting into a film, it is placed in water to solidify for 12-24 hours, and then naturally dried to obtain the WC / WS2 ceramic film green body.

[0011] Furthermore, in step (3), the length of the cut green blank is 1.0~10.0 cm and the width is 0.5~10.0 cm.

[0012] Furthermore, in step (4), the sintering temperature is 1400~1600℃, the holding time is 0.5~4 h, and the heating rate is 2~10℃·min. -1 The atmosphere is argon or nitrogen.

[0013] Furthermore, in step (4), the particle size of the BN powder used for sintering is 0.5~10 μm, the thickness of the lower layer of BN in the embedded powder is 1~10 mm, and the thickness of the upper layer is 1~10 mm.

[0014] Furthermore, in step (4), the composite ceramic membrane uses tungsten carbide phase as a supporting skeleton, and the tungsten boride generated by the reaction is attached in situ to the surface of the tungsten carbide skeleton, and finally a porous composite ceramic membrane rich in WB / WC heterostructure is obtained.

[0015] This invention combines phase transformation casting and powder embedding sintering to prepare a porous WB / WC composite ceramic membrane with excellent performance. It can be used as a self-supporting catalytic electrode in multiple fields. The process is simple, low-cost, and suitable for industrial-scale production. The specific benefits of this invention are as follows: Compared with other catalyst materials, the WB / WC heterostructure in the catalyst prepared by this invention is directly grown in situ on the grain surface of WC ceramics, which have excellent conductivity and high mechanical strength, providing a large number of grain boundaries / phase boundaries, thereby exposing sufficient active sites. Simultaneously, this invention employs a buried powder sintering-in-situ reaction process to grow the WB / WC heterostructure catalytic functional layer in situ on the surface of the WC ceramic substrate, eliminating the polymer binder required for traditional electrode preparation. This fundamentally prevents interfacial failure problems caused by binder decomposition, aging, and detachment, effectively suppressing the detachment of active components and structural instability under various catalytic conditions, and significantly improving the structural reliability and long-term electrochemical stability of the composite catalyst. Furthermore, porous ceramic membranes possess excellent mechanical and chemical stability, and their inherent hydrophilic and gas-repellent surface properties, along with their internal pore structure, facilitate mass and gas transfer. This allows the performance of water electrolysis catalysis based on ceramic membrane electrodes to meet the requirements of high-current-density hydrogen production in industrial applications, and it is suitable for catalytic fields such as hydrogen evolution through water electrolysis, oxygen evolution through water electrolysis, carbon dioxide reduction, alkane dehydrogenation, methanol electrooxidation, and urea electrooxidation. Finally, the raw materials used in this invention are inexpensive, and the preparation technology and processes are mature, simple, and cost-effective, making them suitable for large-scale industrial production. Attached Figure Description

[0016] Figure 1 The casting process in Embodiment 1 of the present invention ( Figure 1 (a) and phase transformation ( Figure 1 (b) Schematic diagram in the middle; Figure 2 The image shows a cross-sectional scanning electron microscope (SEM) image of the WB / WC-Ⅱ composite ceramic membrane obtained in Example 1 of this invention. In the image, (a) corresponds to low magnification and (b) corresponds to high magnification.

[0017] Figure 3 The XRD patterns of the WB / WC composite ceramic membrane and the WC ceramic membrane obtained in Example 1 of this invention after being ground into powder are shown.

[0018] Figure 4 This is a diagram of the three-electrode device used in the electrochemical test in Example 1 of the present invention. Figure 4 (a) and (b) are enlarged views of the working electrode. Figure 4 (b) in the middle.

[0019] Figure 5 The hydrogen evolution LSV curve of the porous WB / WC composite ceramic membrane self-supporting catalytic electrode prepared in Example 1 in an acidic environment ( Figure 5 (a) and the 100-h long-term stability test curve ( Figure 5 (b) in the middle.

[0020] Figure 6 The hydrogen evolution LSV curve of the porous WB / WC composite ceramic membrane self-supporting catalytic electrode prepared in Example 1 in an alkaline environment ( Figure 6 (a) and the 100-h long-term stability test curve ( Figure 6 (b) in the middle.

[0021] Figure 7 The hydrogen evolution Tafel curve and corresponding Tafel slope of the porous WB / WC composite ceramic membrane self-supporting catalytic electrode prepared in Example 1 in an acidic environment. Figure 7 (a) and the Tafel curve of hydrogen evolution in an alkaline environment and the corresponding Tafel slope ( Figure 7 (b) in the middle.

[0022] Figure 8 This is a diagram of the H-type electrolytic cell device used in Embodiment 3 of the present invention.

[0023] Figure 9 This refers to the Faraday efficiency and corresponding bias current density of Cu-BTC-WB / WC-Ⅱ in converting CO2 into formic acid in Example 3 of the present invention.

[0024] Figure 10 This is a comparison of the current density at 0.8 V (vs. RHE) when the porous WB / WC composite ceramic membrane self-supporting catalytic electrode is used for methanol electro-oxidation in Example 4 of the present invention.

[0025] Figure 11 This is a diagram of the apparatus used in Example 5 of the present invention to perform methylcyclohexane dehydrogenation testing using a porous WB / WC-II composite ceramic membrane self-supporting catalytic electrode. Figure 11 (a) and the conversion of catalytic dehydrogenation of methylcyclohexane within 14 hours ( Figure 11 (b) in the middle. Detailed Implementation

[0026] The present invention will be further described below with reference to the accompanying drawings and specific preferred embodiments, but this does not limit the scope of protection of the present invention.

[0027] Example 1 In this embodiment, a self-supporting catalytic electrode based on a porous WB / WC composite ceramic membrane was prepared according to the following steps: (1) Ceramic slurry: WC powder with an average particle size of 1.5 μm and WS2 powder with a particle size of 1 μm were mixed at mass ratios of 10:0, 9:1, 8:2, 7:3, and 6:4, respectively. Then, 1.97% of the total mass of the slurry was added as a dispersant and 25% of the total mass of the slurry was added as a solvent. The mixture was then poured into a ball mill jar for ball milling at a speed of 300 r·min. -1 The ball milling time was 24 hours. Then, 7.31% polyethersulfone (PES) was added as a binder and ball milling continued for another 24 hours to obtain a uniform ceramic slurry. The specific slurry composition is shown in Table 1.

[0028] (2) After degassing the ceramic slurry for 30 minutes, pour it into the casting mold tank and adjust the scraper height to 1.0 mm. The casting process is as follows: Figure 1 The casting speed is controlled at 30 cm·min. -1 After casting, the membrane is placed horizontally in a water bath. After standing for 12 hours, the sample is removed from the water and dried at room temperature for 3 days to obtain a WC / WS2 ceramic membrane green body or a WC ceramic membrane green body.

[0029] (3) Cut the ceramic film blank to a size of 0.6 cm × 1.5 cm.

[0030] (4) The ceramic film green body is placed in a corundum crucible for sintering by embedding powder. The particle size of the BN powder used is 500 nm, the thickness of the lower BN layer is 2.5 mm, and the thickness of the upper layer is 2.5 mm.

[0031] (5) Place the crucible after embedding the ceramic film green body in a corundum tube furnace with flowing argon gas, and heat it at 5℃·min. -1 The temperature was increased to 1500℃ at a heating rate, held for 2 hours, and then increased at a rate of 2℃·min. -1The temperature is reduced to 600℃ and then cooled to room temperature in the furnace to obtain a porous WB / WC composite ceramic membrane or a WC ceramic membrane (slurry without WS2 cannot react to generate WB), which can be directly used as a self-supporting electrode.

[0032] Table 1. Composition of WC and WB / WC slurries (wt%)

[0033] Cross-sectional scanning electron microscope image of the porous WB / WC-II composite ceramic membrane is shown below. Figure 2 As shown in (a) and (b) in the figure. In (a) it can be seen that the ceramic film has an asymmetric finger-shaped through-pore structure with a pore size of 80~100 μm, and there are also many small pores of 0.5~1 μm inside the finger-shaped pores, indicating that it has a hierarchical porous structure; In the microstructure shown in (b), a large number of nanogroove structures are uniformly distributed inside the ceramic film. The groove width is mainly concentrated in the range of 20~80 nm. The groove size is uniform and the distribution is dense.

[0034] Under the conditions of BN buried powder sintering, the W remaining from WS2 decomposition reacts in situ with BN on the surface of tungsten carbide matrix grains to generate WB, thereby reconstructing a large number of WB / WC heterojunctions on the ceramic surface. The relevant reaction process is shown in Equations (1) to (3):

[0035]

[0036]

[0037] Figure 3 The XRD patterns of the prepared WB / WC electrode and the WC electrode after grinding into powder are shown. The diffraction peaks match the standard patterns of WC (JCPDS No. 73-0471) and WB (JCPDS No. 35-0738). The intensity of the WB diffraction peak in the ceramic electrode increases significantly with the increase of WS2 content in the slurry. The WB (112) crystal plane gradually shifts to higher angles by 0.2°~0.5°, corresponding to a decrease in interplanar spacing and shrinkage of cell parameters. This is attributed to the replacement of boron atoms in the WB lattice with carbon atoms of smaller radius. With the increase of WS2 ratio in the raw material powder, the amount of WB generated continues to increase, the crystallinity is significantly improved, and the cell size and lattice parameters decrease, eventually causing its characteristic diffraction peaks to gradually shift to higher angles.

[0038] Using the prepared catalytic electrode as the working electrode and a graphite / platinum electrode as the counter electrode, and saturated silver / silver chloride (corresponding to the acidic system) and saturated mercury / mercury oxide (corresponding to the alkaline system) electrodes as reference electrodes, a three-electrode system was constructed. Electrochemical hydrogen evolution (HER) tests were performed in acidic (0.5 M H₂SO₄) / alkaline (1.0 M KOH) electrolytes (e.g., Figure 4 (As shown). The results are shown in Tables 2 and 3. Figures 5-7 As shown, the hydrogen evolution performance of the catalytic electrode initially increases with the increase of the WS2 precursor mass fraction in the slurry (i.e., the increase of the proportion of WB generated in the electrode), reaching a peak at WC:WS2 = 8:2, and then the performance begins to decrease with further increases in the WS2 precursor mass fraction. The WB / WC-II electrode has an output of 2000 mA·cm⁻¹. -2 The overpotential required for the current density is only 334 mV (acidic) and 294 mV (basic), far lower than that of other catalytic electrodes and commercial Pt / C electrodes, exhibiting excellent hydrogen evolution activity. Furthermore, to verify the industrial application prospects of the prepared catalytic electrode, this embodiment tested the electrode at a high current density (1000 mA·cm⁻¹). -2 ) respectively in 0.5 M H2SO4 (e.g. Figure 5 (b) and 1.0 M KOH ( Figure 6 (b) Long-term stability testing was conducted. The results showed that the electrode could operate stably for over 100 hours under high current conditions in both acidic and alkaline environments, demonstrating excellent durability to meet the needs of practical industrial applications.

[0039] Table 2. HER performance of the WB / WC catalytic electrode prepared in Example 1 in 0.5 M H2SO4 medium.

[0040] Table 3. HER performance of the WB / WC catalytic electrode prepared in Example 1 in 1.0 M KOH medium.

[0041] Example 2 In this embodiment, the self-supporting catalytic electrode based on the porous WB / WC-II composite ceramic membrane prepared in Example 1 is used for electrochemical oxygen evolution (OER) testing. The specific steps are as follows: In an alkaline medium (1.0 M KOH), the following method is used: Figure 4The three-electrode setup shown in (a) uses the prepared porous WB / WC composite ceramic membrane as the working electrode, a saturated mercury / mercuric oxide electrode as the reference electrode, a graphite electrode as the counter electrode, and 1.0 M KOH as the electrolyte. The prepared WB / WC electrode exhibits excellent electrocatalytic oxygen evolution performance. The test results are shown in Table 4. The WB / WC-II electrode outputs 10 mA·cm⁻¹. -2 The required overpotential is 207 mV, and the Tafel slope is 86 mV·dec. -1 They are superior to WC electrodes and other WB / WC electrodes, exhibiting the best oxygen evolution performance.

[0042] Table 4. OER performance of the WB / WC catalytic electrode prepared in Example 2 in 1.0 M KOH medium.

[0043] Example 3 This embodiment uses the self-supporting catalytic electrode based on a porous WB / WC-II composite ceramic membrane prepared in Example 1 for carbon dioxide electroreduction. The specific steps are as follows: Step 1: A two-electrode system was constructed using a porous WB / WC-II composite ceramic membrane as the working electrode and a platinum electrode as the counter electrode. 50 mL of a 1.0 M NaOH solution was taken, and trimesic acid (7:4 mass ratio to NaOH) was added and mixed thoroughly to form the electrolyte. The working electrode was electrodeposited at a constant voltage of 5 V for 3 h to obtain a porous WB / WC-II composite ceramic membrane loaded with trimesic acid.

[0044] Step 2: First, prepare solutions with a concentration of 0.072 g·mL. -1 A copper nitrate aqueous solution with a concentration of 0.036 g·mL -1 The WB / WC-II composite ceramic membrane, after electrodeposition, was placed in an aqueous solution of copper nitrate, and then the ethanolic solution of trimellitic acid was slowly added dropwise to achieve a volume ratio of 1:1. The mixture was then magnetically stirred for 1.0 h, and transferred to a hydrothermal reactor. The membrane was then subjected to hydrothermal reaction at 95 °C for 15 h, resulting in the in-situ formation of a CuMOF nanocube catalytic layer on the surface of the WB / WC-II composite ceramic membrane, denoted as the Cu-BTC-WB / WC-II catalytic electrode.

[0045] like Figure 8As shown, the prepared self-supporting ceramic membrane electrode was inserted into an H-type electrolytic cell as the working electrode, with a platinum sheet electrode as the counter electrode and a saturated silver / silver chloride electrode as the reference electrode. The performance of carbon dioxide electroreduction was tested in a CO2-saturated 0.5 M KHCO3 electrolyte. The H-type electrolytic cell uses a Nafion-117 proton exchange membrane to separate the cathode and anode chambers, effectively avoiding cross-interference between the anode and cathode reactions. The prepared self-supporting ceramic membrane electrode exhibited stable and excellent CO2 electroreduction catalytic activity and product selectivity.

[0046] Figure 9 The Faradaic efficiency and corresponding bias current density of the Cu-BTC-WB / WC-Ⅱ electrode for converting CO2 to formic acid products are shown in the voltage range of 0.6 ~ -1.1 V (vs. RHE). As the voltage increases from 0.6 V (vs. RHE) to 1.1 V (vs. RHE), the Faradaic efficiency (FE) of the formic acid products... Formate The percentage initially increased from 19%, reaching a peak (53%) at 0.9 V (vs. RHE), and then decreased to 31% at 1.1 V (vs. RHE). Regarding current density, the partial current density corresponding to the formic acid product initially increased and then decreased with increasing applied voltage, reaching a maximum of 44.9 mA·cm at 0.9 V (vs. RHE). -2 .

[0047] Example 4 This embodiment uses the self-supporting catalytic electrode based on a porous WB / WC composite ceramic membrane prepared in Example 1 for methanol electro-oxidation. The specific steps are as follows: Constructing a three-electrode system (such as...) Figure 4 (a) Using the prepared catalytic electrode as the working electrode, a platinum electrode as the counter electrode, and a saturated calomel electrode as the reference electrode, the methanol oxidation reaction was tested in a mixed electrolyte of 1.0 M KOH and 0.5 M methanol. Within a voltage range of 0.5 ~ 1.0 V (vs. RHE), the yield of electrochemical products gradually increased with increasing applied voltage. Figure 10 The current densities of different electrodes at 0.8 V (vs. RHE) in different test solutions were compared. The differences in current density directly reflect the electrocatalytic oxidation performance of each electrode for methanol; WB / WC-Ⅱ showed 105.7 mA·cm⁻¹. -2 The maximum current density exhibits the best methanol electro-oxidation performance.

[0048] Example 5 This embodiment uses the self-supporting catalytic electrode based on the porous WB / WC-II composite ceramic membrane prepared in Example 1 for the thermal catalytic dehydrogenation of methylcyclohexane. The specific steps are as follows: A porous WB / WC-II composite ceramic membrane was used as a thermal catalyst and placed in a quartz tube with a diameter of 1.0 cm (e.g., Figure 11 (a) As shown, a mixture of methylcyclohexane and argon was introduced at an operating temperature of 350°C to conduct a methylcyclohexane dehydrogenation test. The methylcyclohexane evaporation temperature was 130°C, the heating temperature was 120°C, and the methylcyclohexane flow rate was 0.03 mL / min. -1 The argon flow rate is 35 mL / min. -1 Collect the generated gas, analyze the hydrogen content in the products, and calculate the conversion rate. For example... Figure 11 As shown in (b), the prepared porous WB / WC-II self-supporting ceramic membrane exhibits stable and excellent thermocatalytic performance for methylcyclohexane dehydrogenation, with the conversion rate remaining at approximately 61.3% for 14 hours. This indicates that the self-supporting catalytic electrode based on the porous WB / WC composite ceramic membrane prepared in this invention also possesses excellent catalytic activity, high-temperature structural stability, and service life in the field of thermocatalytic alkane dehydrogenation. It can efficiently achieve alkane dehydrogenation conversion while avoiding the defects of traditional powder catalysts such as easy agglomeration, difficulty in recovery, and high-temperature sintering deactivation.

[0049] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any person skilled in the art can make many possible variations and modifications to the technical solutions of the present invention, or modify them into equivalent embodiments, without departing from the spirit and technical essence of the present invention. Therefore, any simple modifications, equivalent substitutions, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention, without departing from the content of the technical solutions of the present invention, shall still fall within the scope of protection of the technical solutions of the present invention.

Claims

1. A method for preparing a self-supporting catalytic electrode based on a porous WB / WC composite ceramic membrane, characterized in that, Includes the following steps: (1) Tungsten carbide and tungsten disulfide powders are ball-milled and mixed with solvent, dispersant and binder to obtain a uniform ceramic slurry; (2) The ceramic slurry is degassed, cast, phase-transformed and cured, and then naturally dried to obtain a WC / WS2 ceramic film green body; (3) Cut the ceramic film blank to the required size; (4) The cut ceramic film green body is embedded in BN powder for pressureless sintering. During the powder embedding and sintering process, WB / WC heterostructure is generated in situ on the WC / WS2 ceramic film, thus obtaining a self-supporting catalytic electrode based on porous WB / WC composite ceramic film.

2. The method for preparing a self-supporting catalytic electrode based on a porous WB / WC composite ceramic membrane according to claim 1, characterized in that: In step (1), the mass ratio of tungsten carbide and tungsten disulfide powder is 9:1 to 6:

4.

3. The method for preparing a self-supporting catalytic electrode based on a porous WB / WC composite ceramic membrane according to claim 1, characterized in that: In step (1), the solvent is at least one of N-methylpyrrolidone and methyl ethyl ketone, the dispersant is at least one of KD-1 dispersant, polyvinylpyrrolidone and O-(2-aminopropyl)-O′-(2-methoxyethyl)polypropylene glycol, and the binder is at least one of polyvinyl alcohol, polyvinyl butyral and polyethersulfone.

4. The method for preparing a self-supporting catalytic electrode based on a porous WB / WC composite ceramic membrane according to claim 1, characterized in that: In step (1), the rotational speed of the ball mill is 200~300 r·min. -1 The ball milling time is 24~50 h.

5. The method for preparing a self-supporting catalytic electrode based on a porous WB / WC composite ceramic membrane according to claim 1, characterized in that: In step (2), the ceramic slurry is first degassed for 0.5 to 1 h, then poured into the mold groove, and the height of the casting squeegee is adjusted to 0.5 to 1.1 mm, and the casting speed is 20 to 100 cm·min. -1 After casting into a film, it is placed in water to solidify for 12-24 hours, and then naturally dried to obtain the WC / WS2 ceramic film green body.

6. The method for preparing a self-supporting catalytic electrode based on a porous WB / WC composite ceramic membrane according to claim 1, characterized in that: In step (4), the sintering temperature is 1400~1600℃, the holding time is 0.5~4 h, and the heating rate is 2~10℃·min. -1 The atmosphere is argon or nitrogen.

7. The method for preparing a self-supporting catalytic electrode based on a porous WB / WC composite ceramic membrane according to claim 1, characterized in that: In step (4), the particle size of the BN powder used for sintering is 0.5~10 μm, the thickness of the lower layer of BN in the embedded powder is 1~10 mm, and the thickness of the upper layer is 1~10 mm.

8. The method for preparing a self-supporting catalytic electrode based on a porous WB / WC composite ceramic membrane according to claim 1, characterized in that: In step (4), the composite ceramic membrane uses tungsten carbide as a supporting skeleton, and the tungsten boride generated by the reaction is attached to the surface of the tungsten carbide skeleton in situ, and finally a porous composite ceramic membrane rich in WB / WC heterostructure is obtained.

9. A self-supporting catalytic electrode based on a porous WB / WC composite ceramic membrane prepared by the preparation method according to any one of claims 1 to 8.

10. The application of the self-supporting catalytic electrode based on the porous WB / WC composite ceramic membrane as described in claim 9, characterized in that: It is applied in the catalytic field, including one of the following: water electrolysis for hydrogen evolution, water electrolysis for oxygen evolution, carbon dioxide reduction, urea electro-oxidation, methanol electro-oxidation, or alkane dehydrogenation.

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