Preparation method of three-dimensional porous Ti3C2Tx MXene

Abstract

A preparation method of three-dimensional porous Ti < 3 > C < 2 > T < x > MXene comprises the steps that S1, Ti3AlC2 powder serves as a raw material, an alkaline aqueous solution serves as an etching agent, etching treatment is conducted for 3-6 hours at the temperature of 50-80 DEG C under the normal pressure condition, ultrasonic treatment is conducted for 1-3 hours, and a Ti3AlC2 powder mixture subjected to alkaline etching treatment is obtained; s2, the Ti3AlC2 powder mixture obtained after alkaline etching treatment is filtered and separated through a microfiltration membrane, deionized water is used for washing, impurities are removed, and Ti3AlC2 powder obtained after alkaline etching treatment is obtained; and S3, dispersing the Ti3AlC2 powder subjected to alkaline etching treatment into absolute ethyl alcohol, carrying out ultrasonic treatment for 1-3 hours, filtering and separating by virtue of a microporous filter membrane, washing by virtue of absolute ethyl alcohol, and removing impurities, so as to obtain the three-dimensional porous Ti3C2Tx MXene. Ti3AlC2 powder is directly subjected to alkaline etching to form three-dimensional porous Ti3C2Tx MXene, covalent bonds of the three-dimensional porous Ti3C2Tx MXene are combined with end-capping groups-O and-OH, a large number of sodium ions are intercalated, and the three-dimensional porous Ti3C2Tx MXene has an excellent three-dimensional micro-nano structure and is expected to become an ideal material applied to electromagnetic wave absorption and energy storage. The preparation process is simple, green and safe.

Description

Technical Field

[0001] The present invention relates to a method for preparing MXene, and more particularly to a three-dimensional porous Ti3C2T x MXene preparation method. Background Art

[0002] MXene materials are a class of metal carbides and metal nitrides with a two-dimensional layered structure, and their appearance is similar to that of stacked graphene layers. Due to the unique structure and properties of MXene, it has been widely used in many fields such as electromagnetic wave absorption, energy storage, catalysts, ion sieving, photothermal conversion, field effect transistors, topological insulators, and hydrogen evolution reactions, which has attracted extensive attention worldwide.

[0003] Since 2011, Ti3C2T x MXene was first successfully prepared by Naguib et al. from the research group of Professor Yury Gogotsi at Drexel University in the United States by selectively etching Ti3AlC2 powder with hydrofluoric acid (HF) at room temperature. In the same etching agent HF, various MXene materials have been successively prepared. Naguib et al. first proposed that after removing the A (Al) layer, the MXene (Ti3C2) layer can be separated from the MAX phase (Ti3AlC2) phase, and then through ultrasonic treatment, a new two-dimensional Ti3C2 MXene phase can be obtained, and the effects of etching time, temperature, particle size, and the source of Ti3AlC2 on the preparation of two-dimensional Ti3C2 MXene by the HF method were systematically studied (Naguib, M.; Mashtalir, O.; Carle, J.; et al.; Two-Dimensional Transition Metal Carbides. ACS Nano 2012, 6, 1322-1331.). In addition, the strength of the A bond also determines the etching conditions.

[0004] Due to the use of fluoride-based etching agents in conventional methods, -F, -O, and -OH groups are always covalently bonded to the MXene surface. Generally, MXene can be represented as M n+1 X n T x, where T represents surface capping groups, including –F, –O, and –OH. Due to the presence of hydrogen atoms, the –OH group is not stable and can be replaced by alkali metals (such as Li, Na, and K), alkaline earth metals (such as Mg and Ca), or transition metals (such as Pb). Additionally, at high temperatures, the –OH group can be converted into an –O-type group. Therefore, the MXene surface may be a rather complex combination of one or some of –OH, –O, and –F and other capping groups, and these capping groups greatly affect its properties. However, through chemical treatment, thermal annealing, and mechanical exfoliation processes, MXene can incorporate specific capping groups.

[0005] On the other hand, in order to reduce or eliminate the use of the harmful etchant HF, researchers have been working on finding new methods to prepare more MXene. Currently, Ghidiu et al. (Ghidiu, M.; Lukatskaya, M. R.; Zhao, M.-Q.; et al., Conductive Two-Dimensional Titanium Carbide 'clay' with High Volumetric Capacitance. Nature 2014, 516, 78 - 81.) reported the in-situ formation of HF as an etchant using a mixture of HCl and LiF to replace HF. Compared with the HF etchant, the in-situ formed HF selectively corrodes the 'A' layer, which is a relatively simple, safe, and fast route. The obtained MXene due to the intercalation of water and cations between the MXene layers has a larger interlayer spacing and weaker interactions, and there are no nanoscale defects in the flakes; compared with HF, the properties of LiF and HCl are much milder. Additionally, fluorides such as NaF, KF, CsF, CaF2, etc. can replace LiF, and H2SO4 can replace HCl, and this method has been successfully applied to prepare various MXenes. At the same time, Halim et al. (Halim, J.; Lukatskaya, M. R.; Cook, K. M.; et al.; Transparent Conductive Two-Dimensional Titanium Carbide Epitaxial Thin Films. Chemistry of Materials 2014, 26, 2374 - 2381.) proposed NH4HF2 as a new etchant. Due to the interaction of the obtained MXene film with NH3 and NH4 + ions, the obtained MXene film is a promising material for transparent conductive electrodes, sensors, and other applications.

[0006] Currently, the vast majority of two-dimensional Ti3C2T xMXene nanosheets are prepared by a wet chemical method, synthesized by etching their parent MAX phase Ti3AlC2 powder in a fluorine-based etchant (such as HF, in-situ formed HF, difluorides such as NH4HF2, etc.), and at Ti3C2T x Several capping groups are covalently bonded to the MXene surface, and these groups greatly affect their excellent properties. At the same time, in order to prevent the stacking of layers from affecting their excellent properties, two-dimensional Ti3C2T x MXene nanosheets need to be assembled into three-dimensional Ti3C2T through complex subsequent processing x MXene materials for application in specific fields (such as electromagnetic wave absorption, energy storage, etc.). Existing three-dimensional Ti3C2T x MXene preparation methods first etch the parent MAX phase Ti3AlC2 powder into two-dimensional Ti3C2T with a fluorine-based etchant x MXene nanosheets; then assemble them into a three-dimensional structure through subsequent related processing procedures.

[0007] The invention patent with the application number 201910885633.8 discloses a self-supporting three-dimensional porous MXene foam material and its preparation method. The preparation includes: (1) Preparation of two-dimensional layered MXene; such as Ti3C2T x Preparation of MXene, using LiF added to concentrated hydrochloric acid to form HF in-situ as an etchant, and the etching reaction is carried out for 24 hours. (2) Stir and mix the dispersion of nano sulfur particles (templates) with the aqueous dispersion of two-dimensional layered MXene material, and filter under reduced pressure to form a MXene / sulfur composite film; (3) Remove the sulfur template in the MXene / sulfur composite film. The preparation method disclosed in this patent uses a toxic fluorine-based etchant and has a long etching time; removing the sulfur template requires high-temperature heating or dissolving with a toxic organic solvent.

[0008] The invention patent with the application number 202011057801.3 discloses a high-performance silicon-carbon composite material and its preparation method, and the MXene preparation process involved is as follows: Hydrothermal treatment is carried out under the conditions of a 65% mass fraction sodium hydroxide solution and 270 °C to remove Al in Ti2AlC to prepare the silicon-carbon composite material Si@GE@Ti2C; or hydrothermal treatment is carried out under the conditions of a 65% mass fraction sodium hydroxide solution and 200 °C to remove Al in Ti3AlC2 to prepare the silicon-carbon composite material Si@GE@Ti3C2. In this patent, high-temperature hydrothermal treatment is carried out in a 65% mass fraction sodium hydroxide solution, and the obtained Ti2C or Ti3C2 MXene is in the form of nanosheets, rather than a three-dimensional porous structure.

[0009] Therefore, in order to effectively avoid the toxicity, corrosiveness to the human body and the harm to the environment of fluorine-based etchants, reduce or even eliminate the use of harmful etchants, and accelerate the process of large-scale preparation and functional application, it is urgent to explore a simple, safe and scalable method for preparing three-dimensional Ti3C2T x MXene with controllable surface capping groups, which is also a major challenge. Summary of the Invention

[0010] In view of the deficiencies of the prior art, the present invention proposes a method for directly converting a simple alkaline etching into three-dimensional porous Ti3C2T x MXene. There is no need for toxic fluorine-based etchants, no need for high-temperature heating or dissolving the template with toxic solvents; using an alkaline aqueous solution as the etchant, directly etching the raw material Ti3AlC2 powder into three-dimensional porous MXene, and the etching reaction time is relatively short.

[0011] The present invention develops a simple and safe method for preparing porous Ti3C2T x MXene. By selectively etching the Al layer in MAX phase Ti3AlC2 in an aqueous NaOH solution, a large amount of H2 bubbles are generated and ultrasonic treatment significantly accelerates the etching process; then, through filtration, washing and ultrasonic delamination, the Ti3AlC2 powder is directly etched into a new type of three-dimensional porous Ti3C2T x MXene, which is covalently bonded with surface capping groups –O and –OH, and has a large amount of sodium ion intercalation, and is expected to be used for electromagnetic wave absorption and energy storage, etc. Compared with traditional fluorine-based etchants, the preparation process of the present invention is simple, green and safe, the preparation time is short, no special equipment is required, and it is easy to produce in batches. There is no relevant literature report at present.

[0012] The present invention adopts the following technical solutions:

[0013] Using Ti3AlC2 powder to prepare three-dimensional porous Ti3C2T x MXene, including the following steps:

[0014] Step 1: Using Ti3AlC2 powder as the raw material, adopting an alkaline NaOH aqueous solution (6-9 mol / L) as the etchant, etching at 50-80 °C and normal pressure for 3-6 hours, with a large amount of H2 bubbles generated, and ultrasonic treatment for 1-3 hours to prepare a mixture of Ti3AlC2 powder treated by alkaline etching;

[0015] Step 2: In the mixture of Ti3AlC2 powder treated by alkaline etching prepared in Step 1, filter and separate through a microporous membrane, wash 3-5 times with deionized water to remove impurities, and obtain Ti3AlC2 powder treated by alkaline etching;

[0016] Step 3: Disperse the alkaline-etched Ti3AlC2 powder prepared in Step 2 in absolute ethanol and perform ultrasonic treatment for 1 to 3 hours to expand the interlayer spacing of three-dimensional porous Ti3C2T x MXene, filter and separate through a microporous membrane filter, and then wash with absolute ethanol 3 to 5 times to remove impurities by cleaning, and obtain three-dimensional porous Ti3C2T x MXene;

[0017] Step 4: Dry the three-dimensional porous Ti3C2T x MXene prepared in Step 3 in a vacuum drying oven at 60 to 90 °C for 6 to 10 hours.

[0018] Advantages of the invention:

[0019] 1. In the present invention, an alkaline aqueous solution is used as an etchant to directly alkaline-etch the raw material Ti3AlC2 powder into three-dimensional porous Ti3C2T x MXene, and the etching reaction time is relatively short; using an alkaline NaOH aqueous solution (6 to 9 mol / L) as an etchant, there is no need for toxic and harmful fluorine-based etchants containing fluorine elements, which is green and safe; no template is required, so there is no need for high-temperature heating or dissolving and removing the template with a toxic solvent, and the operation is simple. The prepared three-dimensional porous Ti3C2T x MXene has covalently bonded groups –O and –OH, and has a large amount of sodium ion intercalation, so it has an excellent three-dimensional micro-nano structure and is expected to become an ideal material for electromagnetic wave absorption and energy storage.

[0020] 2. In the present invention, the Ti3AlC2 powder is dispersed in an alkaline NaOH aqueous solution and etched at 50 to 80 °C and normal pressure. At the same time, a large amount of H2 bubbles are generated and ultrasonic treatment accelerates the etching process. The reaction time is 4 to 9 hours, while traditional fluorine-based etchants generally require 24 hours. Its preparation process is simple, the etching reaction time is relatively short, and it is easy to mass-produce.

[0021] 3. For the preparation method of three-dimensional porous Ti3C2T x MXene in the present invention, the alkaline-etched Ti3AlC2 powder is dispersed in absolute ethanol and ultrasonic-treated to obtain three-dimensional porous Ti3C2T x MXene, which can not only expand the interlayer spacing of three-dimensional porous Ti3C2T x MXene, without adding an organic intercalating agent, and after ultrasonic treatment, it is filtered and separated through a microporous membrane filter, which is beneficial to further cleaning and removing impurities; traditional fluorine-based etchants also need to add an organic intercalating agent and require subsequent processing.

[0022] 4. For the three-dimensional porous Ti3C2T xMXene preparation method, using an alkaline aqueous solution as an etchant, directly etching the raw material Ti3AlC2 powder into three-dimensional porous MXene, which has an excellent three-dimensional micro-nano structure, rather than a simple nanosheet structure, without the need for high temperature (200 or 270 °C) and high pressure (reaction in a high-pressure reactor). Description of the Drawings

[0023] Figure 1 is a scanning electron microscope image of Ti3AlC2 powder magnified 5000 times;

[0024] Figure 2 is a scanning electron microscope image of Ti3AlC2 powder magnified 30000 times;

[0025] Figure 3 is a scanning electron microscope image of the alkaline-etched Ti3AlC2 powder magnified 30000 times;

[0026] Figure 4 is a scanning electron microscope image of the alkaline-etched Ti3AlC2 powder magnified 60000 times;

[0027] Figure 5 is a scanning electron microscope image of three-dimensional porous Ti3C2T x MXene magnified 60000 times;

[0028] Figure 6 is the X-ray diffraction pattern of Ti3AlC2 powder and three-dimensional porous Ti3C2T x MXene;

[0029] Figure 7 is the infrared spectrum of Ti3AlC2 powder and three-dimensional porous Ti3C2T x MXene;

[0030] Figure 8 is the X-ray photoelectron spectrum of Ti3AlC2 powder and three-dimensional porous Ti3C2T x MXene; Specific Embodiments

[0031] To make the technical concept and advantages of the present invention for achieving its invention purpose clearer and more understandable, the technical solutions of the present invention will be further described in detail below with reference to the accompanying drawings. It should be understood that the following embodiments are only for explaining and illustrating the preferred embodiments of the present invention, and should not be regarded as and do not constitute a limitation on the scope of the patent protection required by the present invention.

[0032] Example 1

[0033] The present invention uses Ti3AlC2 powder to prepare three-dimensional porous Ti3C2Tx MXene, comprising the following steps:

[0034] The first step: Using Ti3AlC2 powder (see Figure 1 , Figure 2 ) as raw material, using alkaline NaOH aqueous solution as etchant to carry out etching reaction to prepare a mixture of alkaline-etched Ti3AlC2 powder. Specifically as follows:

[0035] (1) In a clean 250 mL beaker, add 100 mL of NaOH aqueous solution (6 mol / L), slowly pour 2 g of Ti3AlC2 powder into it, and heat the mixture to 60 °C using a water bath.

[0036] (2) Etch for 3 hours under normal pressure, with a large amount of H2 bubbles generated, and ultrasonically treat for 2 hours to prepare a mixture of alkaline-etched Ti3AlC2 powder.

[0037] The second step: Filter and separate the mixture of alkaline-etched Ti3AlC2 powder prepared in the first step through a microporous membrane, wash it 3 times with deionized water to remove impurities, and obtain alkaline-etched Ti3AlC2 powder (see Figure 3 , Figure 4 ).

[0038] The microporous membrane is a mixed cellulose ester microporous membrane with a diameter of 80 mm and a pore size of 0.22 μm.

[0039] The third step: Disperse the alkaline-etched Ti3AlC2 powder prepared in the second step in absolute ethanol and ultrasonically treat for 2 hours, filter and separate through a microporous membrane, wash it 3 times with absolute ethanol, and further wash to remove impurities to obtain three-dimensional porous Ti3C2T x MXene. The microporous membrane is a mixed cellulose ester microporous membrane with a diameter of 80 mm and a pore size of 0.22 μm.

[0040] The fourth step: Dry the three-dimensional porous Ti3C2T x MXene prepared in the third step in a vacuum drying oven at 70 °C for 6 hours.

[0041] Figure 1 , Figure 2 Shown are scanning electron microscope images of the raw material MAX phase Ti3AlC2 powder at different magnifications, showing that its particle diameter is 0 - 5 μm.

[0042] Figure 3 , Figure 4Shown are scanning electron microscope images of Ti3AlC2 powder treated by alkaline etching at different magnifications, showing that the Ti3AlC2 powder has been etched into a three-dimensional cross-linked structure with excellent microstructure.

[0043] The three-dimensional porous Ti3C2T prepared as described above x MXene was characterized for its microstructure and composition:

[0044] As Figure 5 shown, it is a scanning electron microscope image of three-dimensional porous Ti3C2T x MXene, showing that it is a three-dimensional porous micro-nano structure composed of countless Ti3C2T x MXene nanosheets or nanoribbons cross-linked together.

[0045] Figure 6 Shown are the X-ray diffraction patterns of Ti3AlC2 powder and three-dimensional porous Ti3C2T x MXene, showing that compared with the Ti3AlC2 powder, the X-ray diffraction (002) peak of three-dimensional porous Ti3C2T x MXene is smaller, and the corresponding interlayer spacing increases;

[0046] Figure 7 Shown are the infrared spectra of Ti3AlC2 powder and three-dimensional porous Ti3C2T x MXene, showing that compared with the Ti3AlC2 powder, the intensities of oxygen-containing groups (O-H, C=O, C-O-C, Ti-O) in three-dimensional porous Ti3C2T x MXene are enhanced, and a new peak (C-H) appears;

[0047] Figure 8 Shown are the X-ray photoelectron spectra of Ti3AlC2 powder and three-dimensional porous Ti3C2T x MXene; showing that compared with the Ti3AlC2 powder, the intensity of the Ti2p peak in three-dimensional porous Ti3C2T x MXene increases (Ti content increases), the intensity of the Al2p peak decreases (Al content decreases), and in particular, a new peak Na1s appears (sodium ion intercalation).

[0048] Example 2

[0049] The preparation method of three-dimensional porous Ti3C2T x MXene in this example is mainly different from that in Example 1 in that: the concentration of the etching agent NaOH aqueous solution is adjusted to 9 mol / L; the mixture is heated to 70 °C by water bath heating.

[0050] Step 1: Using Ti3AlC2 powder as raw material, an alkaline NaOH aqueous solution is used as an etching agent for etching reaction to prepare a mixture of Ti3AlC2 powder treated by alkaline etching. Specifically as follows:

[0051] (1) In a clean 250 mL beaker, add 100 mL of NaOH aqueous solution (9 mol / L), and slowly pour 2 g of Ti3AlC2 powder into it. Heat the mixture to 70 °C using a water bath.

[0052] (2) Etch for 3 hours under normal pressure, accompanied by the generation of a large amount of H2 bubbles, and perform ultrasonic treatment for 2 hours to prepare a mixture of Ti3AlC2 powder treated by alkaline etching.

[0053] Step 2: The mixture of Ti3AlC2 powder treated by alkaline etching prepared in Step 1 is separated by filtration through a microporous membrane, washed 3 times with deionized water to remove impurities, and Ti3AlC2 powder treated by alkaline etching is obtained. The microporous membrane is a mixed cellulose ester microporous membrane with a diameter of 80 mm and a pore size of 0.45 μm.

[0054] Step 3: Disperse the Ti3AlC2 powder treated by alkaline etching prepared in Step 2 in absolute ethanol and perform ultrasonic treatment for 2 hours. Separate by filtration through a microporous membrane, wash 3 times with absolute ethanol, and further wash to remove impurities to obtain three-dimensional porous Ti3C2T x MXene. The microporous membrane is a mixed cellulose ester microporous membrane with a diameter of 80 mm and a pore size of 0.45 μm.

[0055] Step 4: Dry the three-dimensional porous Ti3C2T x MXene prepared in Step 3 in a vacuum drying oven at 80 °C for 6 hours.

[0056] Perform relevant characterizations on the three-dimensional porous Ti3C2T x MXene prepared above. The microscopic morphology and structure of the obtained three-dimensional porous Ti3C2T x MXene are basically the same as those in Example 1.

[0057] Example 3

[0058] The method for preparing three-dimensional porous Ti3C2T x MXene in this example is mainly different from that in Example 1 in that the etching reaction time of the NaOH aqueous solution is adjusted to 6 hours and the ultrasonic treatment time is adjusted to 3 hours.

[0059] Using Ti3AlC2 powder to prepare three-dimensional porous Ti3C2T x MXene includes the following steps:

[0060] Step 1: Using Ti3AlC2 powder as raw material, an alkaline NaOH aqueous solution is used as an etchant for etching reaction to prepare a mixture of Ti3AlC2 powder treated by alkaline etching. Specifically as follows:

[0061] (1) In a clean 250 mL beaker, add 100 mL of an aqueous solution of NaOH (6 mol / L), and slowly pour 2 g of Ti3AlC2 powder into it. Heat the mixture to 60 °C using a water bath.

[0062] (2) Etch for 6 hours under normal pressure, accompanied by the generation of a large amount of H2 bubbles, and perform ultrasonic treatment for 3 hours to prepare a mixture of Ti3AlC2 powder treated by alkaline etching.

[0063] Step 2: The mixture of Ti3AlC2 powder treated by alkaline etching prepared in Step 1 is separated by filtration through a microporous membrane, washed 3 times with deionized water to remove impurities, and Ti3AlC2 powder treated by alkaline etching is obtained. The microporous membrane is a mixed cellulose ester microporous membrane with a diameter of 80 mm and a pore size of 0.22 μm.

[0064] Step 3: Disperse the Ti3AlC2 powder treated by alkaline etching prepared in Step 2 in absolute ethanol and perform ultrasonic treatment for 3 hours. Separate by filtration through a microporous membrane, wash 3 times with absolute ethanol to further remove impurities by washing, and three-dimensional porous Ti3C2T x MXene is obtained. The microporous membrane is a mixed cellulose ester microporous membrane with a diameter of 80 mm and a pore size of 0.22 μm.

[0065] Step 4: The three-dimensional porous Ti3C2T x MXene prepared in Step 3 is dried in a vacuum drying oven at 80 °C for 6 hours.

[0066] The three-dimensional porous Ti3C2T x MXene prepared above is subjected to relevant characterizations of microstructure and composition, and the obtained three-dimensional porous Ti3C2T x MXene has a microstructure and morphology basically consistent with that of Example 1.

[0067] In the present invention, an alkaline NaOH aqueous solution is used as an etchant, without the need for an etchant containing fluorine elements and an organic intercalating agent. The preparation method is simple, green and safe, operates under normal pressure, does not require special equipment, does not require high temperature, greatly shortens the preparation time, and is easy to mass-produce. There is no need to first prepare two-dimensional Ti3C2T x MXene, and then assemble it into three-dimensional Ti3C2T x MXene through a complex subsequent treatment process. Importantly, the Ti3AlC2 powder is directly transformed into three-dimensional porous Ti3C2T through alkaline etching.x MXene, with covalently linked surface capping groups –O and –OH and no –F groups, and with a large amount of sodium ion intercalation, has an excellent microstructure and structure, and is expected to become an ideal nanomaterial for electromagnetic wave absorption and energy storage carriers.

Claims

1. A three-dimensional porous Ti3C2T x A method for preparing MXene, characterized in that: include: Step S1, using Ti3AlC2 powder as a raw material, using an alkaline aqueous solution as an etchant, etching at 50-80° C. and normal pressure to obtain an alkaline-etched Ti3AlC2 powder mixture; Step S2, filtering and separating the alkaline-etched Ti3AlC2 powder mixture obtained in step S1 through a microporous filter membrane, washing with deionized water for 3 to 5 times to remove impurities, and obtaining alkaline-etched Ti3AlC2 powder; Step S3, the Ti3AlC2 powder obtained in step S2 after alkaline etching is dispersed in anhydrous ethanol and subjected to ultrasonic treatment for 1 to 3 hours, filtered and separated by a microporous filter membrane, and washed with anhydrous ethanol for 3 to 5 times to remove impurities, thereby obtaining a three-dimensional porous Ti3C2T x MXene.

2. The three-dimensional porous Ti3C2T according to claim 1 x A method for preparing MXene, characterized in that: In step S1, a 6-9 mol / L alkaline NaOH aqueous solution is used as an etchant. After etching at 50-80°C and normal pressure for 3-6 hours, a large amount of H2 bubbles are generated, and ultrasonic treatment is performed for 1-3 hours to obtain an alkaline-etched Ti3AlC2 powder mixture.

3. The three-dimensional porous Ti3C2T3 according to claim 1 or 2 x A method for preparing MXene, characterized in that: Also includes: Step S4, the three-dimensional porous Ti3C2T prepared in step S3 x MXene was dried in a vacuum oven at 60-90°C for 6-10 hours to obtain three-dimensional porous Ti3C2T x MXene solid powder.

4. The three-dimensional porous Ti3C2T3 according to claim 1 or 2 x A method for preparing MXene, characterized in that: In step S3, the microporous filter membrane is a mixed cellulose ester microporous filter membrane with a diameter of 60 to 90 mm and a pore size of 0.22 μm or 0.45 μm.

5. The three-dimensional porous Ti3C2T3 according to claim 3 x A method for preparing MXene, characterized in that: In step S3, the microporous filter membrane is a mixed cellulose ester microporous filter membrane with a diameter of 60 to 90 mm and a pore size of 0.22 μm or 0.45 μm.

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