A preparation method and application of Mo2TiC2 MXene material
Mo2TiC2 MXene was prepared by high-temperature solid-state method and anhydrous etching method, which solved the problems of HF acid contamination and stability, and expanded its application fields.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- XI AN JIAOTONG UNIV
- Filing Date
- 2024-04-22
- Publication Date
- 2026-07-14
AI Technical Summary
Existing methods for preparing MXenes use toxic HF acid, leading to contamination and reduced stability. Furthermore, there are insufficient preparation routes for other types of MXenes, limiting their application potential.
Two-dimensional carbide crystals Mo2TiAlC2 were prepared by a high-temperature solid-state method, and Al was etched by dissolving ammonium chloride solution in anhydrous dimethyl sulfoxide to avoid the use of HF acid, thus preparing Mo2TiC2 MXene material.
A green and environmentally friendly MXene preparation process has been achieved, which improves the stability of the material and expands its application potential in hydrogen storage, catalyst support, lithium-ion battery electrodes and supercapacitor electrode materials.
Smart Images
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Abstract
Description
Technical Field
[0001] This invention relates to the field of nanomaterials, specifically to a method for preparing Mo2TiC2 MXene material and its application. Background Technology
[0002] MXenes are a class of two-dimensional materials represented by transition metal carbides or nitrides. Their high tunability and multifunctionality have made them a hot topic in materials science research. The preparation method of MXenes greatly affects their structure and properties; therefore, in-depth research on MXene synthesis is crucial for their application development. Wet chemical methods are one of the earliest techniques used to prepare MXenes, involving the chemical exfoliation of the MAX phase (where M is a transition metal element, A is mainly a group 13 or 14 element, and X is carbon or nitrogen) in a fluorinated acid medium (such as HF solution). Selective etching of the A layer elements in the precursor MAX phase using chemical methods can yield novel two-dimensional nanomaterials called MXenes.
[0003] However, chemical etching generates a large amount of non-recyclable and difficult-to-manage waste. Furthermore, most current preparation methods rely primarily on water as the main solvent for selectively etching Al, and the introduction of intercalated water during the preparation process significantly reduces the stability of MXenes. Currently, large-scale MXene preparation processes mainly focus on the Ti3C2MXene series, while preparation routes for other MXenes are still under exploration. Therefore, it is necessary to develop anhydrous MXene etching methods to further enhance the application potential of MXenes. Summary of the Invention
[0004] The purpose of this invention is to provide a method for preparing and applying Mo2TiC2 MXene material that is simple in process steps, mild in reaction, easy to control, avoids the use of highly corrosive and toxic HF acid, and is green, environmentally friendly and pollution-free.
[0005] To achieve the above objectives, the preparation method employed in this invention includes the following steps:
[0006] 1) Molybdenum powder, titanium powder, aluminum powder and graphite powder are mixed and ground in a molar ratio of (1.8-2.2):(0.8-1.2):(1-1.5):(1.8-2.0) to obtain a precursor mixture;
[0007] 2) The precursor mixture was transferred to a tube furnace. Under inert gas protection, the tube furnace was heated from room temperature to 1500-1700℃ at a heating rate of 2-6℃ / min and kept at the temperature for 2-8h to obtain Mo2TiAlC2MAX.
[0008] 3) Stir (0.5-1)g Mo2TiAlC2 MAX, (0.5-4)g ammonium chloride and 20-40mL dimethyl sulfoxide to obtain a homogeneous mixture;
[0009] 4) Transfer the mixture to a Teflon-lined stainless steel reactor and etch it in an oven at 100-180℃ for 1-5 days;
[0010] 5) The precipitate obtained by etching is washed with anhydrous ethanol, then washed with deionized water and vacuum dried to obtain Mo2TiC2 MXene.
[0011] The purity of the molybdenum powder, titanium powder, aluminum powder, and graphite powder is all analytical grade.
[0012] The mixing and grinding in step 1) is carried out by wet grinding with ethanol, and then dried after grinding to obtain the precursor mixture.
[0013] In step 2), the inert gas introduced is argon gas with a pressure of 0.02-0.08 MPa and a flow rate of 20-100 cc / min.
[0014] In step 5), the precipitate is washed 2-3 times with anhydrous ethanol.
[0015] The Mo2TiC2 MXene material prepared by the above method is used as a hydrogen storage material, catalyst support, lithium-ion battery electrode, and supercapacitor electrode material.
[0016] Compared with existing technologies, this invention first prepares a two-dimensional carbide crystal Mo2TiAlC2 using a high-temperature solid-state method. Mo2TiAlC2 is a quaternary layered compound in which three M-layer atoms occupy two 4f and one 2a Wyckoff positions, respectively. In its outer layers, Mo and Ti account for 75% and 25%, respectively. The middle layer is entirely composed of Ti atoms, with Mo atoms occupying the middle M-layer (arranged in a face-centered cubic lattice) surrounded by C atoms. Its atomic stacking sequence is Mo-Ti-Mo-Al-Mo-Ti-Mo, consisting of three MX-layers stacked alternately with one A-plane. Mo2TiAlC2 is then etched using an ammonium chloride solution dissolved in dimethyl sulfoxide, utilizing Cl... - The Al in the two-dimensional carbide crystal Mo2TiAlC2 is etched away to obtain Mo2TiC2 MXene material. The preparation method is simple, the reaction is mild and easy to control, and it avoids the use of HF acid, which is highly corrosive and toxic. Attached Figure Description
[0017] Figure 1 These are XRD patterns of Mo2TiAlC2 MAX and Mo2TiC2 MXene materials prepared in Example 1 of this invention;
[0018] Figure 2 This is a SEM image of the Mo2TiC2 MXene material prepared in Example 1 of this invention;
[0019] Figure 3 This is an XPS image of the Mo2TiC2 MXene material prepared in Example 1 of this invention;
[0020] Figure 4 This is the Raman diagram of the Mo2TiC2 MXene material prepared in Example 1 of this invention. Detailed Implementation
[0021] The present invention will be further explained and described below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0022] This invention provides a method for preparing Mo2TiC2 MXene material. First, a two-dimensional carbide crystal, Mo2TiAlC2, is prepared via a high-temperature solid-state method. Then, the Mo2TiAlC2 is etched using an ammonium chloride solution dissolved in dimethyl sulfoxide to remove the Al atomic layer from the two-dimensional carbide crystal, thus obtaining the MXene material. Specifically, the method includes:
[0023] 1) Molybdenum powder, titanium powder, aluminum powder, and graphite powder are added to a mortar in a molar ratio of (1.8-2.2):(0.8-1.2):(1-1.5):(1.8-2.0), ground with alcohol, and dried at 35°C for 12 hours to obtain a precursor mixture; preferably, the molar ratio of molybdenum powder, titanium powder, aluminum powder, and graphite powder is 2:1:1.5:2; preferably, the purity of molybdenum powder, titanium powder, and aluminum powder is analytical grade, and the graphite powder is artificial graphite powder;
[0024] 2) The precursor mixture is transferred to a tube furnace, an inert gas is introduced, and the temperature of the tube furnace is increased to 1500-1700℃ at 2-6℃ / min and kept at the temperature for 2-8 hours to obtain two-dimensional carbide crystals Mo2TiAlC2; preferably, the temperature of the tube furnace is increased to 1600℃ at 4℃ / min and kept at the temperature for 4 hours; the inert gas is a flowing argon atmosphere.
[0025] 3) Mix 0.5-1g Mo2TiAlC2 MAX, 0.5-4g ammonium chloride, and 20-40mL dimethyl sulfoxide evenly and stir for 10 minutes. Preferably, the mass ratio of Mo2TiAlC2 to ammonium chloride is 1:3.33; preferably, the volume of dimethyl sulfoxide is 20mL; transfer the mixture to a 50mL Teflon-lined stainless steel reactor and place it in an oven. Set the temperature to 100-180℃ and the etching time to 1-5 days; preferably, the temperature is 150℃ and the time is 5 days.
[0026] 4) Place the obtained mixture in a 50mL centrifuge tube, add anhydrous ethanol and centrifuge at 3500rpm / min for 3min. Discard the supernatant and repeat 3 times. Finally, vacuum dry at 60℃ for 12h to obtain MXene material.
[0027] The present invention will now be described in detail through specific embodiments.
[0028] Example 1:
[0029] 1) Analytical grade molybdenum powder, titanium powder, aluminum powder and graphite powder, all with a particle size of 200 mesh, were mixed in a molar ratio of 2:1:1.5:2 and wet-milled with ethanol. After milling, the mixture was dried to obtain a precursor mixture.
[0030] 2) The precursor mixture was transferred to a tube furnace and heated from room temperature to 1600℃ at a rate of 4℃ / min under argon protection at a pressure of 0.05MPa and a flow rate of 80cc / min. The mixture was kept at the same temperature for 4h to obtain Mo2TiAlC2 MAX block powder, which was then ground through a 40-micron sieve.
[0031] 3) Mix 0.6g Mo2TiAlC2 MAX, 2g ammonium chloride and 20mL dimethyl sulfoxide until homogeneous to obtain a mixture;
[0032] 4) Transfer the mixture to a Teflon-lined stainless steel reactor and etch it in an oven at 150°C for 5 days;
[0033] 5) The precipitate obtained by etching was washed by centrifugation with anhydrous ethanol at a speed of 3500 rpm / min for 3 min. The supernatant was discarded and the mixture was washed by centrifugation three times. After washing with deionized water, it was dried under vacuum at 60℃ to obtain Mo2TiC2 MXene.
[0034] XRD analysis was performed on the Mo2TiAlC2 and MXene materials prepared in Example 1, see [link to relevant documentation]. Figure 1 ,from Figure 1As can be seen, the Al layer in the original Mo2TiAlC2 was etched, and the (002) peak was significantly shifted, thus successfully obtaining MXene.
[0035] SEM analysis was performed on the MXene material prepared in Example 1, see [link to relevant documentation]. Figure 2 ,from Figure 2 As can be seen, MXene exhibits a distinct accordion-like layered structure.
[0036] XPS analysis was performed on the MXene material prepared in Example 1, see [link to relevant documentation]. Figure 3 ,from Figure 3 As can be seen, the Al layer of MXene is etched, and there is no Al 2p signal.
[0037] Raman analysis was performed on the MXene material prepared in Example 1, see [reference needed]. Figure 4 ,from Figure 4 The disappearance of the M-Al bond signal in MXene indicates that Al has been etched.
[0038] Example 2:
[0039] 1) Analytical grade molybdenum powder, titanium powder, aluminum powder and graphite powder, all with a particle size of 200 mesh, were mixed in a molar ratio of 2:1:1.3:2 and wet-milled with ethanol. After milling, the mixture was dried to obtain a precursor mixture.
[0040] 2) The precursor mixture was transferred to a tube furnace and heated from room temperature to 1600℃ at a rate of 4℃ / min under argon protection at a pressure of 0.02MPa and a flow rate of 20cc / min. The mixture was kept at the same temperature for 4h to obtain Mo2TiAlC2 MAX powder, which was then ground through a 40-micron sieve.
[0041] 3) Mix 0.6g Mo2TiAlC2 MAX, 4g ammonium chloride and 20mL dimethyl sulfoxide until homogeneous to obtain a mixture;
[0042] 4) Transfer the mixture to a Teflon-lined stainless steel reactor and etch it in an oven at 150°C for 3 days;
[0043] 5) The precipitate obtained by etching was washed by centrifugation with anhydrous ethanol at a speed of 3500 rpm / min for 3 min. The supernatant was discarded and the mixture was washed by centrifugation three times. After washing with deionized water, it was dried under vacuum at 60℃ to obtain Mo2TiC2 MXene.
[0044] Example 3:
[0045] 1) Analytical grade molybdenum powder, titanium powder, aluminum powder and graphite powder with a particle size of 200 mesh were mixed in a molar ratio of 2:1:1.3:1.8 and wet-milled with ethanol. After milling, the mixture was dried to obtain the precursor mixture.
[0046] 2) The precursor mixture was transferred to a tube furnace and heated from room temperature to 1600℃ at a rate of 4℃ / min under argon protection at a pressure of 0.08MPa and a flow rate of 100cc / min. The mixture was kept at the same temperature for 4h to obtain Mo2TiAlC2MAX block powder, which was then ground through a 40-micron sieve.
[0047] 3) Mix 0.6g Mo2TiAlC2 MAX, 2g ammonium chloride and 20mL dimethyl sulfoxide until homogeneous to obtain a mixture;
[0048] 4) Transfer the mixture to a Teflon-lined stainless steel reactor and etch it in an oven at 180°C for 1 day;
[0049] 5) The precipitate obtained by etching was washed by centrifugation with anhydrous ethanol at a speed of 3500 rpm / min for 3 min. The supernatant was discarded, and the mixture was washed by centrifugation twice. After washing with deionized water, it was dried under vacuum at 60℃ to obtain Mo2TiC2 MXene.
[0050] Example 4:
[0051] 1) Analytical grade molybdenum powder, titanium powder, aluminum powder and graphite powder, all with a particle size of 200 mesh, were mixed in a molar ratio of 2:1:1.5:2 and wet-milled with ethanol. After milling, the mixture was dried to obtain a precursor mixture.
[0052] 2) The precursor mixture was transferred to a tube furnace and heated from room temperature to 1600℃ at a rate of 2℃ / min under argon protection at a pressure of 0.04MPa and a flow rate of 50cc / min. The mixture was kept at the same temperature for 4h to obtain Mo2TiAlC2 MAX block powder, which was then ground through a 40-micron sieve.
[0053] 3) Mix 0.8g Mo2TiAlC2 MAX, 2g ammonium chloride and 30mL dimethyl sulfoxide until homogeneous to obtain a mixture;
[0054] 4) Transfer the mixture to a Teflon-lined stainless steel reactor and etch it in an oven at 150°C for 3 days;
[0055] 5) The precipitate obtained by etching was washed by centrifugation with anhydrous ethanol at a speed of 3500 rpm / min for 3 min. The supernatant was discarded and the mixture was washed by centrifugation three times. After washing with deionized water, it was dried under vacuum at 60℃ to obtain Mo2TiC2 MXene.
[0056] Example 5:
[0057] 1) Analytical grade molybdenum powder, titanium powder, aluminum powder and graphite powder with a particle size of 200 mesh were mixed in a molar ratio of 1.8:0.8:1:1.8 and wet-milled with ethanol. After milling, the mixture was dried to obtain a precursor mixture.
[0058] 2) The precursor mixture was transferred to a tube furnace and heated from room temperature to 1500℃ at a rate of 5℃ / min under argon protection at a pressure of 0.06MPa and a flow rate of 60cc / min. The mixture was kept at the same temperature for 8 hours to obtain Mo2TiAlC2 MAX block powder, which was then ground through a 40-micron sieve.
[0059] 3) Mix 0.5g Mo2TiAlC2 MAX, 0.5g ammonium chloride and 20mL dimethyl sulfoxide to obtain a homogeneous mixture;
[0060] 4) Transfer the mixture to a Teflon-lined stainless steel reactor and etch it in an oven at 100°C for 5 days;
[0061] 5) The precipitate obtained by etching was washed by centrifugation with anhydrous ethanol at a speed of 3500 rpm / min for 3 min. The supernatant was discarded and the mixture was washed by centrifugation three times. After washing with deionized water, it was dried under vacuum at 60℃ to obtain Mo2TiC2 MXene.
[0062] Example 6:
[0063] 1) Analytical grade molybdenum powder, titanium powder, aluminum powder and graphite powder, all with a particle size of 200 mesh, were mixed in a molar ratio of 2.2:1.2:1.2:1.9 and wet-milled with ethanol. After milling, the mixture was dried to obtain a precursor mixture.
[0064] 2) The precursor mixture was transferred to a tube furnace and heated from room temperature to 1700℃ at a rate of 6℃ / min under argon protection at a pressure of 0.03MPa and a flow rate of 40cc / min. The mixture was kept at the same temperature for 2h to obtain Mo2TiAlC2 MAX block powder, which was then ground through a 40-micron sieve.
[0065] 3) Mix 1.0g Mo2TiAlC2 MAX, 3g ammonium chloride and 40mL dimethyl sulfoxide to obtain a homogeneous mixture;
[0066] 4) Transfer the mixture to a Teflon-lined stainless steel reactor and heat it in an oven at 120°C for 4 days;
[0067] 5) The precipitate obtained by etching was washed by centrifugation with anhydrous ethanol at a speed of 3500 rpm / min for 3 min. The supernatant was discarded and the mixture was washed by centrifugation three times. After washing with deionized water, it was dried under vacuum at 60℃ to obtain Mo2TiC2 MXene.
[0068] This invention involves uniformly mixing a layered Mo2TiAlC2 MAX phase compound with an ammonium chloride solution dissolved in dimethyl sulfoxide, and then conducting a solvothermal reaction in a Teflon-lined stainless steel reactor. The mixture is then washed with anhydrous ethanol solution, and the washed sample is dried under vacuum at a specific temperature for a certain period to obtain MXene material. This invention provides a method for preparing MXene that does not involve toxic or harmful HF acids, completely etching away the Al in the MAX phase to obtain MXene. The method is green, environmentally friendly, pollution-free, and the reaction is mild, easy to control, and simple to operate, making it suitable for large-scale production. Therefore, it has significant application prospects in many fields, such as hydrogen storage, catalyst supports, lithium-ion battery electrodes, and supercapacitor electrode materials.
[0069] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.
Claims
1. A method for preparing Mo2TiC2MXene material, characterized in that, Includes the following steps: 1) Molybdenum powder, titanium powder, aluminum powder and graphite powder are mixed and ground in a molar ratio of (1.8-2.2):(0.8-1.2):(1-1.5):(1.8-2.0) to obtain a precursor mixture; 2) The precursor mixture was transferred to a tube furnace. Under inert gas protection, the tube furnace was heated from room temperature to 1500-1700℃ at a heating rate of 2-6℃ / min and kept at the temperature for 2-8h to obtain Mo2TiAlC2MAX. 3) Stir (0.5-1) g Mo2TiAlC2MAX, (0.5-4) g ammonium chloride and 20-40 mL of dimethyl sulfoxide until homogeneous to obtain a mixture; 4) Transfer the mixture to a Teflon-lined stainless steel reactor and etch it in an oven at 100-180℃ for 1-5 days; 5) The precipitate obtained by etching is washed with anhydrous ethanol, then washed with deionized water and dried under vacuum to obtain Mo2TiC2MXene.
2. The method for preparing Mo2TiC2MXene material according to claim 1, characterized in that, The purity of the molybdenum powder, titanium powder, aluminum powder, and graphite powder is all analytical grade.
3. The method for preparing Mo2TiC2MXene material according to claim 1, characterized in that, The mixing and grinding in step 1) is carried out by wet grinding with ethanol, and then dried after grinding to obtain the precursor mixture.
4. The method for preparing Mo2TiC2MXene material according to claim 1, characterized in that, In step 2), the inert gas introduced is argon gas with a pressure of 0.02-0.08 MPa and a flow rate of 20-100 cc / min.
5. The method for preparing Mo2TiC2MXene material according to claim 1, characterized in that, In step 5), the precipitate is washed 2-3 times with anhydrous ethanol.