A porous titanium-based mxenes composite electrocatalytic membrane, a preparation method and application thereof

Abstract

The present application belongs to the technical field of electrocatalysis, and particularly relates to a porous titanium-based Mxenes composite electrocatalytic film as well as a preparation method and application thereof. The present application discloses a porous titanium-based Mxenes composite electrocatalytic film, which comprises a support film and a catalytic film arranged on at least one surface of the support film. The support film comprises a porous titanium metal, and the catalytic film comprises Mxenes. The porous titanium-based Mxenes composite electrocatalytic film takes Mxenes with high catalytic activity as a functional layer, significantly improves the mineralization and degradation effect of the electrocatalytic film on organic pollutants in water, effectively reduces the pollution of the catalytic film, improves the stability and applicability of the composite electrocatalytic film, and increases the service life and use scenarios of the electrocatalytic film.

Description

Technical Field

[0001] This invention belongs to the field of electrocatalysis technology, specifically relating to a porous titanium-based Mxenes composite electrocatalytic membrane, its preparation method, and its application. Background Technology

[0002] Social production and human activities generate a large amount of pollutants that enter the ecological environment. These pollutants are bioaccumulative, difficult to biodegrade, and carcinogenic, and they also disrupt the circulatory systems of organisms, posing serious harm to both the environment and human health, ultimately threatening human survival. Electrochemical advanced oxidation technology has broad application prospects due to its advantages such as high efficiency, multifunctionality, simple operation, and easy scalability. Among them, anode materials can effectively degrade pollutants through direct and indirect oxidation. Therefore, the performance and stability of anode materials largely determine the efficiency, applicable scenarios, and service life of electrochemical advanced oxidation technology.

[0003] Recent studies have shown that combining membrane technology with anode materials to form electrocatalytic membrane technology organically couples electrochemical advanced oxidation technology and membrane separation technology: membrane separation technology weakens the diffusion boundary layer by enhancing convection mass transfer, thus improving the electrochemical degradation efficiency; electrochemical technology can effectively mitigate membrane fouling while degrading pollutants, thereby improving pollutant removal and degradation efficiency. This technology can effectively remove organic pollutants, inorganic pollutants, and heavy metals from water bodies, making it an ideal method for advanced treatment. However, current electrocatalytic membrane technology is not yet perfect and cannot effectively remove pollutants from water bodies; therefore, further in-depth research on electrocatalytic membrane technology is necessary. Summary of the Invention

[0004] This invention is based on the inventor's discoveries and understanding of the following facts and problems:

[0005] The performance of electrocatalytic membranes is mainly based on their electrochemical functions, which include two aspects: ion transport and electron conduction. Mxenes materials have fast ion transport and electron conduction capabilities, exhibiting excellent catalytic activity and are widely used in electrocatalysis applications.

[0006] In the literature (ACS Applied Materials & Interfaces, 2022, 14(1): 1838-1849), a high-performance reverse osmosis composite membrane was prepared by interfacial polymerization of Mxenes and polyamide-based membranes. This method can improve the chemical compatibility between Mxenes nanosheets and polyamide matrix, which helps to form a tight network structure. The electric field repulsion effectively alleviates the deposition rate of negatively charged model compounds such as sodium alginate and bovine serum albumin on the membrane surface, and effectively improves the salt rejection rate (>96%) and antifouling performance. Although the electrocatalytic membrane has good electrochemical stability and pollutant removal performance, it has poor water pressure resistance. When the water pressure is high, the electrocatalytic membrane is prone to damage, resulting in a decrease in pollutant removal efficiency.

[0007] This invention aims to at least partially solve one of the technical problems in related technologies. To this end, embodiments of this invention propose a porous titanium-based Mxenes composite electrocatalytic membrane. This membrane uses highly catalytically active Mxenes as a functional layer, significantly improving the mineralization and degradation effect of the electrocatalytic membrane on organic pollutants in water, effectively reducing membrane fouling, improving the stability and applicability of the composite electrocatalytic membrane, and increasing its service life and application scenarios.

[0008] The porous titanium-based Mxenes composite electrocatalytic membrane of this invention includes a support membrane and a catalytic membrane disposed on at least one surface of the support membrane. The support membrane comprises porous titanium metal, and the catalytic membrane comprises Mxenes.

[0009] The advantages and technical effects of the porous titanium-based Mxenes composite electrocatalytic membrane in this invention are as follows: 1. In this invention, porous titanium metal has a rich pore structure, which allows Mxenes to form a good loading on its surface, resulting in a composite electrocatalytic membrane with better stability and support; 2. In this invention, porous titanium, as an electrode material, has good electrochemical properties, is stable, high-temperature resistant, and has excellent corrosion resistance, making the resulting composite electrocatalytic membrane suitable for deep treatment fields with complex pollutants and harsh treatment conditions; 3. In this invention, using highly catalytically active Mxenes as the main functional layer increases the specific surface area of ​​the surface active layer of the electrocatalytic membrane, increases the number of active sites in the electrocatalytic membrane, ensures that the composite catalytic membrane has good catalytic and retention performance, and significantly improves the mineralization and degradation effect on organic pollutants in water; 4. In this invention, through the doping modification of Mxenes, the stability and applicability of the composite electrocatalytic membrane can be significantly improved, effectively reducing catalytic membrane pollution and increasing the service life and application scenarios of the electrocatalytic membrane.

[0010] In some embodiments, the thickness of the support film is 10-15 mm; and / or, the thickness of the catalyst film is 1-3 mm.

[0011] This invention also provides a method for preparing a porous titanium-based Mxenes composite electrocatalytic membrane, comprising the following steps:

[0012] (1) Mix urea and titanium powder and press them together. Then calcine the pressed film to obtain a porous titanium-based film.

[0013] (2) Mix Mxenes, polyvinylidene fluoride and dimethylformamide to form a slurry;

[0014] (3) The slurry obtained in step (2) is coated on at least one surface of the porous titanium substrate obtained in step (1), and then calcined to obtain a porous titanium Mxenes composite electrocatalytic membrane.

[0015] The advantages and technical effects of the preparation method of the porous titanium-based Mxenes composite electrocatalytic membrane in this invention are as follows: 1. The method of this invention first prepares a porous titanium substrate as a support membrane, which allows the catalytic material to be better loaded on its surface, forming a more stable and supportive composite electrocatalytic membrane; 2. The method of this invention loads Mxenes material with good catalytic activity onto the surface of the porous titanium substrate, increasing the specific surface area of ​​the active layer on the electrocatalytic membrane surface, increasing the number of active sites on the electrocatalytic membrane, effectively improving the electrocatalytic oxidation performance of the electrode, and strengthening the catalytic performance of the electrode; 3. The method of this invention adds polyvinylidene fluoride to the preparation of the Mxenes slurry, which enables it to be uniformly mixed with Mxenes to form a basic material for the catalytic layer. The addition of dimethylformamide enables the basic material for the catalytic layer to be better miscible to form the slurry; 4. The method of this invention is simple to operate, has high production efficiency, and the obtained composite electrocatalytic membrane has better electrocatalytic performance, which is convenient for promotion and application in industrial production.

[0016] In some embodiments, in step (1), the average particle size of the urea is 100-400 μm; the average particle size of the titanium powder is 20-45 μm; and / or, the mass ratio of the urea to the titanium powder is 1:50-1:100.

[0017] In some embodiments, in step (1), the pressing is performed using a hot press, and the pressing pressure is 2 to 4 MPa.

[0018] In some embodiments, step (1), the calcination includes: placing the diaphragm in a vacuum furnace, raising the temperature inside the vacuum furnace to 400-600°C at a rate of 2-8°C / min under a vacuum of 5-20 Pa, then cooling the diaphragm to room temperature with the vacuum furnace, and then transferring the diaphragm to a horizontal carbon nanotube sintering furnace for sintering, wherein the vacuum degree of the horizontal carbon nanotube sintering furnace is 10 Pa. -4 -10 -5 Pa, the sintering temperature is 1000~1400℃, and the sintering time is 8~12 hours.

[0019] In some embodiments, in step (2), the mass ratio of Mxenes, polyvinylidene fluoride and dimethylformamide is (6-8):(1-3):(1-3).

[0020] In some embodiments, in step (3), the calcination is carried out under an inert atmosphere, the calcination temperature is 100-140°C, and the calcination time is 20-26 hours.

[0021] In some embodiments, in step (3), the coating is performed using a coating machine with a speed of 10 to 30 mm / s.

[0022] The present invention also provides an application of the above-described porous titanium-based Mxenes composite electrocatalytic membrane or the porous titanium-based Mxenes composite electrocatalytic membrane prepared by the above-described preparation method in wastewater treatment. Attached Figure Description

[0023] Figure 1 Here are the SEM images and elemental distribution maps of the porous titanium-based Mxenes composite electrocatalytic membrane prepared in Example 1;

[0024] Figure 2 These are cyclic voltammetry curves of the electrocatalytic membranes prepared in Example 1 and Comparative Example 1;

[0025] Figure 3 The graphs show the degradation rates of atenolol by the porous titanium-based Mxenes composite electrocatalytic membranes prepared in each embodiment and comparative example. Detailed Implementation

[0026] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0027] The porous titanium-based Mxenes composite electrocatalytic membrane of this invention includes a support membrane and a catalytic membrane disposed on at least one surface of the support membrane. The support membrane comprises porous titanium metal, and the catalytic membrane comprises Mxenes.

[0028] The porous titanium-based Mxenes composite electrocatalytic membrane of this invention utilizes the abundant pore structure of porous titanium metal, which allows Mxenes to form a good loading on its surface, resulting in a composite electrocatalytic membrane with better stability and support. Porous titanium, as an electrode material, possesses excellent electrochemical properties, exhibiting stability, high temperature resistance, and excellent corrosion resistance. The resulting composite electrocatalytic membrane is suitable for advanced treatment applications involving complex pollutants and demanding processing conditions. Using highly catalytically active Mxenes as the main functional layer increases the specific surface area of ​​the active layer of the electrocatalytic membrane, enhances the number of active sites, and ensures good catalytic and retention performance, significantly improving the mineralization and degradation of organic pollutants in water. Mxenes doping modification significantly improves the stability and applicability of the composite electrocatalytic membrane, effectively reduces membrane fouling, and increases the membrane's lifespan and application scenarios.

[0029] In some embodiments, the thickness of the supporting membrane is 10-15 mm; and / or, the thickness of the catalytic membrane is 1-3 mm. In these embodiments, the preferred thicknesses of the supporting membrane and the catalytic membrane are beneficial for further improving the catalytic performance of the composite electrocatalytic membrane. If the supporting membrane is too thick, it will hinder the retention of pollutants; if the supporting membrane is too thin, it cannot effectively support the catalytic membrane, affecting the rigidity of the overall structure. If the catalytic membrane is too thick, it will affect the membrane separation process of pollutants; if the catalytic membrane is too thin, it will weaken the catalytic effect.

[0030] This invention also provides a method for preparing a porous titanium-based Mxenes composite electrocatalytic membrane, comprising the following steps:

[0031] (1) Mix urea and titanium powder and press them together. Then calcine the pressed film to obtain a porous titanium-based film.

[0032] (2) Mix Mxenes, polyvinylidene fluoride and dimethylformamide to form a slurry;

[0033] (3) The slurry obtained in step (2) is coated on at least one surface of the porous titanium substrate obtained in step (1), and then calcined to obtain a porous titanium Mxenes composite electrocatalytic membrane.

[0034] The method for preparing a porous titanium-based Mxenes composite electrocatalytic membrane according to embodiments of the present invention first prepares a porous titanium substrate as a support membrane, which allows the catalytic material to be better loaded on its surface, forming a more stable and supportive composite electrocatalytic membrane. In this embodiment, Mxenes material with good catalytic activity is loaded on the surface of the porous titanium substrate, increasing the specific surface area of ​​the active layer on the electrocatalytic membrane surface, increasing the number of active sites on the electrocatalytic membrane, effectively improving the electrocatalytic oxidation performance of the electrode, and strengthening the catalytic performance of the electrode. In this embodiment, polyvinylidene fluoride is added to the preparation of the Mxenes slurry, which enables it to be uniformly mixed with Mxenes to form the basic material of the catalytic layer. The addition of dimethylformamide can make the basic material of the catalytic layer more miscible to form the slurry. The method of this embodiment is simple and easy to operate, has high production efficiency, and the obtained composite electrocatalytic membrane has better electrocatalytic performance, which is convenient for promotion and application in industrial production.

[0035] In some embodiments, preferably, in step (1), the average particle size of the urea is 100–400 μm, and the average particle size of the titanium powder is 20–45 μm. More preferably, in step (1), the mass ratio of the urea to the titanium powder is 1:50–1:100. Even more preferably, the purity of the titanium powder is 99.9%, and the oxygen content is less than 0.5%.

[0036] In this embodiment of the invention, the average particle size of urea and titanium powder and their ratio are preferred, which enables the prepared porous titanium to have a suitable porosity, thereby ensuring that the composite electrocatalytic membrane can effectively retain pollutants and has better electrocatalytic efficiency.

[0037] In some embodiments, preferably, in step (1), the pressing is performed using a hot press, and the pressing pressure is 2-4 MPa. More preferably, in step (1), the calcination includes: placing the diaphragm in a vacuum furnace, raising the temperature inside the vacuum furnace to 400-600°C at a rate of 2-8°C / min under a vacuum of 5-20 Pa, then cooling the diaphragm to room temperature with the vacuum furnace, and then transferring the diaphragm to a horizontal carbon nanotube sintering furnace for sintering, wherein the vacuum degree of the horizontal carbon nanotube sintering furnace is 10 MPa. -4 Pa, the sintering temperature is 1000~1400℃, and the sintering time is 8~12 hours.

[0038] In some embodiments, preferably, in step (2), the mass ratio of Mxenes, polyvinylidene fluoride, and dimethylformamide is (6-8):(1-3):(1-3). More preferably, the mass ratio of Mxenes, polyvinylidene fluoride, and dimethylformamide is 8:1:1.

[0039] In this embodiment of the invention, the dosage ratio of Mxenes, polyvinylidene fluoride and dimethylformamide is further optimized, which is beneficial to forming a uniform catalyst layer slurry and enabling the catalyst layer to effectively exert its catalytic performance.

[0040] In some embodiments, preferably, in step (3), the calcination is carried out under an inert atmosphere, the calcination temperature is 100-140°C, and the calcination time is 20-26 hours. More preferably, in step (3), the coating is carried out using a coating machine, and the speed of the coating machine is 10-30 mm / s.

[0041] In this embodiment of the invention, the calcination temperature and time are further optimized, which is conducive to the uniform evaporation of solvent in the slurry, so that Mxenes and porous titanium substrate are tightly bonded together, ensuring the stability of the composite electrocatalytic membrane.

[0042] The present invention also provides an application of the above-described porous titanium-based Mxenes composite electrocatalytic membrane or the porous titanium-based Mxenes composite electrocatalytic membrane prepared by the above-described preparation method in wastewater treatment.

[0043] The technical solution of the present invention will now be described in detail with reference to specific embodiments and accompanying drawings.

[0044] Example 1

[0045] (1) Mix 1g of urea with a particle size of 150μm with 50g of titanium powder with a purity of 99.9%, an oxygen content of 0.4%, and an average particle size of 25μm. Stir the mixture thoroughly in a mortar. Then, press the mixture in a hydraulic press at a pressure of 2MPa. Place the pressed membrane in a vacuum furnace and raise the temperature in the vacuum furnace to 500℃ at a heating rate of 5℃ / min under a vacuum of 10Pa. Then, cool the membrane to room temperature in the vacuum furnace and transfer it to a horizontal carbon tube sintering furnace. -4 Porous titanium-based material was obtained by high vacuum (Pa) and high temperature sintering at 1200℃ for 10 hours.

[0046] (2) Mix Mxenes, polyvinylidene fluoride and dimethylformamide in a mass ratio of 8:1:1 to obtain a slurry;

[0047] (3) The slurry is placed in a coating machine and coated on a porous titanium substrate at a speed of 20 mm / s. Then, it is calcined at 120°C for 24 hours under a nitrogen atmosphere to obtain a porous titanium-based Mxenes composite electrocatalytic membrane. The porous titanium metal support membrane has a thickness of 10 mm, and the catalytic membrane with Mxenes as the main functional layer has a thickness of 1 mm.

[0048] Example 2

[0049] (1) Mix 1g of urea with a particle size of 250μm with 50g of titanium powder with a purity of 98%, an oxygen content of 0.4%, and an average particle size of 30μm. Stir the mixture thoroughly in a mortar. Then, press the mixture in a hydraulic press at a pressure of 2MPa. Place the pressed membrane in a vacuum furnace and raise the temperature in the vacuum furnace to 500℃ at a heating rate of 5℃ / min under a vacuum of 10Pa. Then, cool the membrane to room temperature in the vacuum furnace and transfer it to a horizontal carbon tube sintering furnace. -4 Porous titanium-based material was obtained by high vacuum (Pa) and high temperature sintering at 1200℃ for 10 hours.

[0050] (2) Mix Mxenes, polyvinylidene fluoride and dimethylformamide in a mass ratio of 6:2:2 to obtain a slurry;

[0051] (3) The slurry is placed in a coating machine and coated on a porous titanium substrate at a speed of 20 mm / s; then it is calcined at 120°C for 24 hours under a nitrogen atmosphere to obtain a porous titanium-based Mxenes composite electrocatalytic membrane; wherein the thickness of the porous titanium metal support membrane is 10 mm and the thickness of the catalytic membrane with Mxenes as the main functional layer is 1 mm.

[0052] Comparative Example 1

[0053] (1) Mix 1g of urea with a particle size of 150μm with 50g of titanium powder with a purity of 99.9%, an oxygen content of 0.4%, and an average particle size of 25μm. Stir the mixture thoroughly in a mortar. Then, press the mixture in a hydraulic press at a pressure of 2MPa. Place the pressed membrane in a vacuum furnace and raise the temperature in the vacuum furnace to 500℃ at a heating rate of 5℃ / min under a vacuum of 10Pa. Then, cool the membrane to room temperature in the vacuum furnace and transfer it to a horizontal carbon tube sintering furnace. -4 Porous titanium-based material was obtained by sintering under high vacuum of Pa and high temperature of 1200℃ for 10 hours.

[0054] (2) Polyvinylidene fluoride and dimethylformamide are mixed in a mass ratio of 5:5 to obtain a slurry;

[0055] (3) The slurry is placed in a coating machine and coated on a porous titanium substrate at a speed of 20 mm / s. Then, it is calcined at 120°C for 24 hours under a nitrogen atmosphere to obtain a porous titanium-based composite electrocatalytic membrane. The thickness of the porous titanium metal support membrane is 10 mm and the thickness of the catalytic membrane is 1 mm.

[0056] Comparative Example 2

[0057] The preparation method of this comparative example is the same as that of Example 1, except that the porous titanium metal in step (1) is not prepared, and a titanium-based Mxenes composite electrocatalytic membrane is prepared using a titanium metal thin film as the substrate. The thickness of the titanium metal thin film is 1 mm.

[0058] In the titanium-based Mxenes composite electrocatalytic membrane prepared in this comparative example, the thickness of the titanium metal film is 1 mm and the thickness of the catalyst layer is 1 mm.

[0059] Performance testing

[0060] (1) The electrocatalytic membranes prepared in Examples 1-2 and Comparative Examples 1-2 were characterized by SEM.

[0061] The SEM image and elemental distribution map of the porous titanium-based Mxenes composite electrocatalytic membrane prepared in Example 1 are shown below. Figure 1 As shown, from Figure 1 As can be seen, Mxenes particles are uniformly present on the surface of the porous titanium-based Mxenes composite electrocatalytic membrane. The Mxenes particles are composed of stacked layers. The elemental distribution shows that the atomic percentages of Ti, C, F and Cl are 26.18%, 28.08%, 18.52% and 0.01%, respectively, confirming that the porous titanium-based Mxenes composite electrocatalytic membrane was successfully prepared by this method.

[0062] In Example 2, the atomic percentages of Ti, C, F, and Cl in the porous titanium-based Mxenes composite electrocatalytic membrane were 24.2%, 22.1%, 12.5%, and 0.01%, respectively.

[0063] In Comparative Example 1, the composite electrocatalytic membrane did not show the presence of F and Cl elements due to the absence of Mxenes material.

[0064] In Comparative Example 2, the atomic percentages of Ti, C, F, and Cl were 24.3%, 22.2%, 12.3%, and 0.01%, respectively.

[0065] (2) Electrical Cycling Performance Test

[0066] Test conditions: Cyclic voltammetry curves of the electrocatalytic membrane were measured at 10 mV / s in 0.5 M H2SO4 solution.

[0067] Cyclic voltammetry curves of the electrodes Figure 2 The results show that the integral area of ​​the porous titanium-based Mxenes composite electrocatalytic membrane prepared in Example 1 is larger than that of the porous titanium electrocatalytic membrane prepared in Comparative Example 1. This indicates that loading Mxenes material onto porous titanium can improve the catalytic oxidation activity of the electrocatalytic membrane and enhance the performance of the electrode.

[0068] (3) Degradation rate test of atenolol

[0069] Test method: Atenolol (aqueous solution concentration of 30 mg / L) was used as the target pollutant. An electrocatalytic membrane was used as the anode and a stainless steel mesh as the cathode, with a current density of 5 mA / cm². 2 The removal efficiency of the porous titanium-based Mxenes composite electrocatalytic membrane for atenolol was tested under the specified conditions. The degradation rate curves of atenolol by the composite electrocatalytic membranes prepared in Examples 1-2 and Comparative Examples 1-2 are shown in the figure. Figure 3 As shown, the test results are shown in Table 1.

[0070] Table 1

[0071] Example 1 Example 2 Comparative Example 1 Comparative Example 2 10-minute degradation rate 100％ 95％ 42％ 26％ Membrane flux decline rate 1％ 2％ 15％ 10％

[0072] Through Table 1 and Figure 3 It can be seen that within a 10-minute processing time, the porous titanium-based Mxenes composite electrocatalytic membrane prepared in Example 1 achieved a 100% degradation rate of atenolol with a 1% decrease in membrane flux; the porous titanium-based Mxenes composite electrocatalytic membrane prepared in Example 2 achieved a 95% degradation rate of atenolol with a 2% decrease in membrane flux; the porous titanium electrocatalytic membrane prepared in Comparative Example 1 achieved a 42% degradation rate of atenolol with a 15% decrease in membrane flux; and the porous titanium electrocatalytic membrane prepared in Comparative Example 2 achieved a 26% degradation rate of atenolol with a 10% decrease in membrane flux. Therefore, the porous titanium-based Mxenes composite electrocatalytic membrane significantly improved the degradation rate of atenolol and significantly enhanced its resistance to membrane fouling.

[0073] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0074] Although the above embodiments have been shown and described, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Any changes, modifications, substitutions and variations made to the above embodiments by those skilled in the art are within the protection scope of the present invention.

Claims

1. Application of a porous titanium-based Mxenes composite electrocatalytic membrane in sewage treatment, characterized in that, The porous titanium-based Mxenes composite electrocatalytic film comprises a support film and a catalytic film arranged on at least one surface of the support film, the support film comprises a porous titanium metal, the thickness of the support film is 10-15 mm, the catalytic film comprises Mxenes, the pollutants in the sewage are organic pollutants, and the porous titanium-based Mxenes composite electrocatalytic film is an anode.

2. Use of the porous titanium-based Mxenes composite electrocatalytic membrane according to claim 1 in wastewater treatment, characterized in that, The thickness of the catalytic film is 1-3 mm.

3. Use of the porous titanium-based Mxenes composite electrocatalytic membrane according to claim 1 in wastewater treatment, characterized in that, The preparation method of the porous titanium-based Mxenes composite electrocatalytic film comprises the following steps: (1) mixing urea or polyether sulfone and titanium powder, then pressing, calcining the pressed film sheet to obtain a porous titanium base; (2) mixing Mxenes, polyvinylidene fluoride and dimethylformamide to form a slurry; (3) coating the slurry obtained in the step (2) on at least one surface of the porous titanium base obtained in the step (1), and then calcining to obtain a porous titanium-based Mxenes composite electrocatalytic film.

4. Use of the porous titanium-based Mxenes composite electrocatalytic membrane according to claim 3 in wastewater treatment, characterized in that, In the step (1), the average particle size of the urea is 100-400 μm, and the average particle size of the titanium powder is 20-45 μm; and / or, the mass ratio of the urea to the titanium powder is 1:50-1:

100.

5. Use of the porous titanium-based Mxenes composite electrocatalytic membrane according to claim 3 in wastewater treatment, characterized in that, In the step (1), the pressing is performed by using a hot press, and the pressing pressure is 2-4 MPa.

6. Use of the porous titanium-based Mxenes composite electrocatalytic membrane according to claim 3 in wastewater treatment, characterized in that, In the step (1), the calcining comprises: placing the film into a vacuum furnace, increasing the temperature in the vacuum furnace to 400-600 °C at a rate of 2-8 °C / min under a vacuum degree of 5-20 Pa, then cooling the film to room temperature along with the vacuum furnace, and then transferring the film to a horizontal carbon tube sintering furnace for sintering, wherein the vacuum degree of the horizontal carbon tube sintering furnace is 10 -4 -10 -5 Pa, the sintering temperature is 1000-1400 °C, and the sintering time is 8-12 hours.

7. Use of the porous titanium-based Mxenes composite electrocatalytic membrane according to claim 3 in wastewater treatment, characterized in that, In the step (2), the mass ratio of the Mxenes, polyvinylidene fluoride and dimethylformamide is (6-8):(1-3):(1-3).

8. Use of the porous titanium-based Mxenes composite electrocatalytic membrane according to claim 3 in wastewater treatment, characterized in that, In the step (3), the calcining is performed in an inert atmosphere, the calcining temperature is 100-140 °C, and the calcining time is 20-26 hours.

9. Use of the porous titanium-based Mxenes composite electrocatalytic membrane according to claim 3 or 8 in wastewater treatment, characterized in that, In the step (3), the coating is performed by using a film coating machine, and the speed of the film coating machine is 10-30 mm / s.

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