Large-scale preparation method of Ti3AlC2-based MXene nano-roll

Abstract

The invention belongs to the technical field of inorganic nano materials, and particularly relates to a large-scale preparation method of a Ti3AlC2-based MXene nano roll. The method comprises the following steps: by taking bottom mud obtained after etching two-dimensional Ti3AlC2 by HF as a raw material, stirring for hydrolysis reaction under the dispersion of a solvent system to form a precursor; adding ammonia water into the precursor, and carrying out dehydration condensation to form an MXene / SiO2 composite material; hF is added into the MXene / SiO2 composite material, ultrasonic treatment is carried out, so that an MXene sheet layer is curled, and the Ti3AlC2-based MXene nanometer roll is obtained. Through the innovative process of weakening interlayer acting force through SiO2 intercalation and directionally driving curling through HF micro-explosion, the core problems that interlayer stripping is difficult, the structure is uncontrollable and oxidation stability is poor in MXene nano-roll preparation are solved, and meanwhile the method has the advantages of being high in yield, low in energy consumption and environmentally friendly.

Description

Technical Field

[0001] This invention belongs to the field of inorganic nanomaterials technology, specifically relating to a method for the large-scale preparation of Ti3AlC2-based MXene nanorolls. Background Technology

[0002] Nanoscrolls are hollow tubular topologies formed by rolling up 2D nanosheets. While retaining the excellent properties of 2D nanomaterials, they also exhibit some unique characteristics, thus finding wide application in energy storage, catalysis, and adsorption. MXenes (such as Ti3C2T) x MXene nanorolls are a class of two-dimensional materials with high electrical conductivity (>6000 S / cm), abundant surface functional groups (-O, -OH, -F), and excellent mechanical properties. Due to their open ion transport channels, high specific surface area, and adaptive strain characteristics, MXene nanorolls have attracted much attention in the fields of energy storage, flexible electronics, and electromagnetic wave absorption and shielding. However, existing MXene nanoroll fabrication technologies still face the following key bottlenecks: ① Strong interlayer interactions: The van der Waals forces and hydrogen bonds between the layers of MXene nanosheets are significantly stronger than those of graphene and other materials. Conventional intercalating agents (such as tetramethylammonium hydroxide) are difficult to effectively weaken the interlayer bonding forces, resulting in low self-rolling efficiency (<10%); ② Chemical instability: MXene is easily oxidized in water or oxygen-containing environments (generating TiO2, MoO3, etc.). Traditional high-temperature / high-pressure processes (such as hydrothermal methods) will accelerate its structural degradation, causing a loss of conductivity (decreased by >50%) and a reduction in active sites; ③ Low yield: Since MXene nanorolls are usually formed by rolling up few layers of MXene, the yield of few-layer MXene is low, resulting in a very low yield of nanorolls that cannot meet application requirements.

[0003] To prepare nanorolls, researchers have used KC8 and strong oxidants (ozone and fuming nitric acid) as intercalating agents, combined with ultrasonic treatment to induce the self-rolling of graphene nanosheets. Zheng et al. (Zheng J, Liu H, Wu B, Guo Y, Wu T, Yu G, Liu Y, Zhu D. Production of high-quality carbon nanoscrolls with microwave spark assistance in liquid nitrogen. Adv. Mater. 2011, 23: 2460-2463. https: / / doi.org / 10.1002 / adma.201004759) reported the preparation of high-quality carbon nanorolls from natural bulk graphite flakes under microwave spark-assisted treatment in liquid nitrogen. The expansion effect generated by microwave irradiation and the contraction effect generated by liquid nitrogen cooling induced surface strain in the graphite flakes. Combined with the bubbles generated by heat release, this led to the self-assembly of graphene sheets into nanorolls. However, the above methods require strict helium and liquid nitrogen conditions to achieve rolling, and the preparation process is accompanied by the release of large amounts of toxic gases (NO2, NO, CO), making it difficult to achieve mass production. Summary of the Invention

[0004] The purpose of this invention is to provide a method for the large-scale preparation of Ti3AlC2-based MXene nanorolls. Based on an innovative process that uses SiO2 intercalation to weaken interlayer forces and HF micro-explosion to drive directional rolling, this method solves the core problems of difficult interlayer peeling, uncontrollable structure, and poor oxidation stability in MXene nanoroll preparation. It also boasts advantages such as high yield (kilogram-level), low energy consumption (room temperature and pressure), and environmental friendliness (HF recycling), providing a foundation for the large-scale preparation of Ti3C2-based MXene nanorolls. x The commercial application of MXene high-performance devices has been supported by key technologies.

[0005] The present invention solves the above-mentioned technical problems through the following technical solutions.

[0006] The purpose of this invention is to provide a method for the large-scale preparation of Ti3AlC2-based MXene nanorolls, comprising the following steps: S1. Using the substrate after etching two-dimensional Ti3AlC2 with HF as the raw material for tetraethyl orthosilicate, the mixture is dispersed in a solvent system and stirred to carry out a hydrolysis reaction, so that SiO2 nanoparticles are generated in situ between MXene layers to form a precursor.

[0007] S2. Ammonia water is added to the precursor to carry out a dehydration condensation reaction, so that SiO2 nanoparticles are anchored in situ between MXene sheets to form MXene / SiO2 composite material.

[0008] S3. HF is added to the MXene / SiO2 composite material and ultrasonication is performed. HF etches the SiO2 between the layers to generate gaseous SiF4, which triggers a microscale explosion effect, causing the MXene sheets to curl up and obtain Ti3AlC2-based MXene nanorolls.

[0009] Furthermore, the ratio of the mud and tetraethyl orthosilicate used after HF etching of two-dimensional Ti3AlC2 is 0.6g:30mL~60mL.

[0010] Furthermore, the ratio of sludge to solvent after HF etching of two-dimensional Ti3AlC2 was 0.6g:30mL~60mL, the solvent was ethanol, the hydrolysis reaction temperature was 30℃~50℃, the time was 6h~12h, and the stirring rate was 300rpm.

[0011] Furthermore, the ratio of the sediment to ammonia water after HF etching of two-dimensional Ti3AlC2 is 0.6g:40mL~60mL, and the concentration of ammonia water is 16wt.%~18wt.%.

[0012] Furthermore, the dehydration condensation reaction is carried out at a temperature of 40℃ to 60℃ for a time of 5h to 8h.

[0013] Furthermore, the ratio of HF to mud after etching two-dimensional Ti3AlC2 was 0.6 g: 30 mL.

[0014] Furthermore, the ultrasound frequency is 40 kHz, and the duration is 2 to 6 hours.

[0015] Furthermore, after the ultrasound is completed, centrifugation, washing, and vacuum drying are performed in sequence, with the vacuum drying temperature ranging from 50℃ to 80℃.

[0016] Furthermore, the method for preparing the sediment after HF etching of two-dimensional Ti3AlC2 includes the following steps: After mixing lithium fluoride and hydrochloric acid, Ti3AlC2 was added, and the mixture was etched in a water bath at 35°C for 24 hours. After the etching was completed, the supernatant was removed to obtain the mud after HF etching of two-dimensional Ti3AlC2.

[0017] Furthermore, the ratio of lithium fluoride to hydrochloric acid is 2g:40mL, and the concentration of hydrochloric acid is 9M; the mass ratio of lithium fluoride to Ti3AlC2 is 1:1.

[0018] Compared with the prior art, the present invention has the following advantages: The large-scale preparation method provided by this invention uses etched Ti3C2 as raw material and is based on an innovative process of SiO2 intercalation to weaken interlayer forces and HF micro-explosion to drive directional curling. Specifically, the mud from HF-etched two-dimensional Ti3AlC2 is mixed with tetraethyl orthosilicate (TEOS) and dispersed in a solvent. Hydrolysis is performed through rapid stirring, and TEOS undergoes hydrolysis and condensation, gradually generating SiO2 nanoparticles in situ between MXene layers. This achieves controllable SiO2 intercalation to weaken interlayer forces, significantly increasing the interlayer spacing and effectively reducing van der Waals forces and hydrogen bonds, providing a driving force for subsequent curling. The process is further enhanced by HF micro-explosion. This method, employing an explosion-driven directional curling technique, involves immersing the intercalated MXene / SiO2 composite material in a specific concentration of HF solution. Under ultrasonic conditions, HF preferentially etches the interlayer SiO2 to generate gaseous SiF4, triggering a microscale explosion effect. The released mechanical energy causes the MXene sheets to directionally curl along the weak intercalation surfaces. This approach solves the core challenges in MXene nanoroll fabrication, such as difficult interlayer exfoliation, uncontrollable structure, and poor oxidation stability. It also boasts advantages such as high yield (kilogram-level), low energy consumption (room temperature and pressure), and environmental friendliness (HF recycling). With its high production volume and efficiency, it has industrial production potential and is suitable for Ti3C2T. x The commercial application of MXene high-performance devices has been supported by key technologies. Attached Figure Description

[0019] Figure 1 This is a scanning electron microscope image of the sediment after HF etching of two-dimensional Ti3AlC2 according to the present invention.

[0020] Figure 2 This is a scanning electron microscope image of the Ti3AlC2-based MXene nanorolls prepared in Example 1 of this invention.

[0021] Figure 3 This is a scanning electron microscope image of the Ti3AlC2-based MXene nanorolls prepared in Example 2 of the present invention.

[0022] Figure 4 This is a scanning electron microscope image of the Ti3AlC2-based MXene nanorolls prepared in Example 3 of the present invention.

[0023] Figure 5 This is a scanning electron microscope image of the Ti3C2Tx MXene material prepared in Comparative Example 1 of this invention.

[0024] Figure 6 This is a scanning electron microscope image of the Ti3C2Tx MXene material prepared in Comparative Example 2 of this invention. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] It should be noted that the technical terms used in this invention are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of this invention. Unless otherwise specified, all raw materials, reagents, instruments and equipment used in the following embodiments of this invention can be purchased from the market or prepared by existing methods.

[0027] Existing techniques for preparing MXene nanorolls using KC8 and strong oxidants as intercalating agents, or through microwave spark-assisted treatment in liquid nitrogen, still suffer from several drawbacks: Extreme and demanding preparation conditions: They rely on experimental environments that are difficult to achieve on a large scale. For example, they require strict inert gas (helium) protection or extremely low temperature media (liquid nitrogen), placing extremely high demands on equipment and operations. The process is hazardous and highly polluting: The preparation involves highly corrosive / explosive chemicals (such as fuming nitric acid and ozone), accompanied by the release of large amounts of toxic and harmful gases (such as NO2, NO, and CO), posing serious safety and environmental hazards. Difficulty in large-scale production: Limited by the aforementioned extreme conditions and hazards, these methods are essentially exploratory technologies at the laboratory scale, unable to be safely and economically scaled up for production, severely limiting their practical applications.

[0028] Based on this, the present invention provides a novel method for large-scale preparation of high-quality Ti3AlC2MXene nanorolls under mild, inert conditions, and the unique nanoroll structure can simultaneously solve the problems of self-stacking and oxidation sensitivity of Ti3AlC2MXene nanosheets. Details are as follows:

[0029] This invention provides a method for the large-scale preparation of Ti3AlC2-based MXene nanorolls, comprising the following steps: S1. Using the substrate after etching two-dimensional Ti3AlC2 with HF as raw material, the substrate is dispersed in a solvent system and stirred at 30℃~50℃ for 6h~12h for hydrolysis reaction, so that SiO2 nanoparticles are generated in situ between MXene layers to form a precursor.

[0030] In this invention, the sediment from HF etching of two-dimensional Ti3AlC2 is mixed and dispersed with tetraethyl orthosilicate (TEOS) in a solvent. Hydrolysis is then performed through rapid stirring, leading to TEOS hydrolysis and condensation. This gradually generates SiO2 nanoparticles in situ between the MXene layers, achieving controllable intercalation of SiO2 to weaken interlayer forces, significantly increasing the interlayer spacing, and effectively reducing van der Waals forces and hydrogen bonding, thus providing a driving force for subsequent curling. It should be noted that in conventional HF etching of Ti3AlC2 to prepare MXene, the upper solution is used for separation, and the lower sediment (i.e., sediment) is simply discarded. This invention reuses this sediment to prepare materials with a unique nano-roll structure.

[0031] In some embodiments, the sediment after HF etching of two-dimensional Ti3AlC2 is prepared by conventional HF etching method. The preparation method of the sediment after HF etching of two-dimensional Ti3AlC2 specifically includes the following steps: 2g of lithium fluoride (LiF) and 40mL of 9M hydrochloric acid were stirred at 400 rpm for 30min in a polytetrafluoroethylene beaker. 2g of Ti3AlC2 was slowly added under water bath heating at 35℃, and etching was performed for 24h. After etching, the supernatant was discarded, and the lower precipitate was repeatedly washed to obtain the sludge after HF etching of two-dimensional Ti3AlC2.

[0032] In some embodiments, the ratio of the mud after HF etching of two-dimensional Ti3AlC2 to tetraethyl orthosilicate is 0.6 g: 30 mL to 60 mL. In this invention, tetraethyl orthosilicate hydrolyzes to generate SiO2 nanoparticles in situ between MXene layers. Therefore, if the amount of tetraethyl orthosilicate is too small, the amount of intercalated SiO2 will be insufficient, and the mechanical energy released by the microscale explosion effect induced by HF etching of SiO2 under ultrasonic conditions will be insufficient to cause directional curling of the MXene sheets. If the amount of tetraethyl orthosilicate is too large, a large amount of SiO2 will be generated on the surface of the MXene sheets, which not only wastes HF but also cancels out the mechanical energy released by the interlayer microscale explosion, resulting in the inability to generate nanoparticles.

[0033] In some embodiments, the ratio of HF-etched two-dimensional Ti3AlC2 sediment to solvent is 0.6 g: 30 mL to 60 mL, the solvent is ethanol, and the stirring speed is 300 rpm to 500 rpm. It should be noted that after the hydrolysis reaction is complete, centrifugation is required at a speed of 3000 r / min to 6000 r / min to obtain a solid precursor.

[0034] S2. Add ammonia to the precursor and carry out a dehydration condensation reaction at 40℃~60℃ for 5h~8h to anchor SiO2 nanoparticles in situ between MXene sheets to form MXene / SiO2 composite material.

[0035] In this invention, in OH - Under catalysis, SiO2 fills the gaps between the sheets, anchoring the SiO2 nanoparticles in situ between the MXene sheets. The MXene sheets are "spread out" and fixed by the in-situ generated SiO2 particles. In addition, the small amount of SiO2 remaining on the surface can effectively prevent the MXene from recombinizing.

[0036] In some embodiments, the ratio of the sediment after HF etching of two-dimensional Ti3AlC2 to ammonia is 0.6g:40mL-60mL, and the concentration of ammonia is 16wt.%-18wt.%. In this invention, ammonia provides an alkaline environment; excessive ammonia leads to high alkalinity, causing the prepared SiO2 to easily agglomerate, which is detrimental to intercalation; insufficient alkalinity results in uneven SiO2 size, which is also unfavorable for preparing uniform nanorolls. It should be noted that after the sol-gel reaction is complete, centrifugation is required at a speed of 3000r / min-6000r / min to obtain the MXene / SiO2 composite material.

[0037] S3. HF is added to the MXene / SiO2 composite material and ultrasonicated at 40KHz for 2h to 6h. HF etches the SiO2 between the layers to generate gaseous SiF4, which triggers a microscale explosion effect, causing the MXene sheets to curl up, thus obtaining Ti3AlC2-based MXene nanorolls.

[0038] In this invention, the intercalated MXene / SiO2 composite material is immersed in a certain concentration of HF solution through HF micro-explosion-driven directional curling. Under ultrasonic conditions, HF preferentially etches the interlayer SiO2 to generate gaseous SiF4, triggering a microscale explosion effect. The released mechanical energy causes the MXene sheets to directionally curl along the weak intercalation surface.

[0039] In some embodiments, the ratio of HF used to etch two-dimensional Ti3AlC2 sediment to HF is 0.6 g: 25 mL to 35 mL.

[0040] In some embodiments, after ultrasounding, centrifugation (3000 r / min to 6000 r / min), washing (washing with ethanol and water in sequence), and vacuum drying are performed sequentially. The vacuum drying temperature is 50°C to 80°C, and the time is 6 hours.

[0041] In summary, this invention uses etched Ti3C2 as raw material and employs an innovative process based on SiO2 intercalation to weaken interlayer forces and HF micro-explosion to directionally drive the roll formation. This process generates nanorolls in situ during the exfoliation of nanosheets, solving the core challenges of difficult interlayer exfoliation, uncontrollable structure, and poor oxidation stability in MXene nanoroll preparation. Simultaneously, it boasts advantages such as high yield (kilogram-level), low energy consumption (room temperature and pressure), and environmental friendliness (HF recycling). With its high production volume and efficiency, it has industrial production potential and is a promising candidate for Ti3C2T... x The commercial application of MXene high-performance devices has been supported by key technologies.

[0042] The following specific examples will provide further explanation.

[0043] Example 1 A method for large-scale preparation of Ti3AlC2-based MXene nanorolls includes the following steps: S1. 2g of lithium fluoride (LiF) and 40mL of 9M hydrochloric acid were stirred at 400 rpm for 30min in a polytetrafluoroethylene (PTFE) beaker. Under a 35℃ water bath, 2g of Ti3AlC2 was slowly added, and etching was performed for 24h. After etching, the supernatant was discarded, and the lower precipitate was repeatedly washed to obtain the HF-etched two-dimensional Ti3AlC2 sediment. A scanning electron microscope (SEM) image of the HF-etched two-dimensional Ti3AlC2 sediment is shown below. Figure 1 As shown.

[0044] S2. Take 0.6 g of the HF-etched Ti3AlC2 sediment, add 30 mL of ethanol and 30 mL of TEOS sequentially, and then stir rapidly at 300 rpm in a 30°C water bath for 12 h. After the reaction is complete, centrifuge and add 50 mL of ammonia water (V) to the solid. 水 V 浓氨水 =2:3), and then reacted at 50℃ for 6h; after the reaction, centrifuged, added 30mL of HF to the solid, and reacted under ultrasonic conditions at 40KHz for 4h; after the reaction, centrifuged, washed with ethanol and water in sequence, and finally vacuum dried at 60℃ for 6h to obtain Ti3AlC2-based MXene nanorolls.

[0045] Figure 2 This is a scanning electron microscope (SEM) image of the Ti3AlC2-based MXene nanorolls prepared in Example 1 of this invention. Figure 2 As shown in the figure, the prepared Ti3C2T x MXene contains a large number of roll-based structures.

[0046] Example 2 A method for large-scale preparation of Ti3AlC2-based MXene nanorolls includes the following steps: S1. 2g of lithium fluoride (LiF) and 40mL of 9M hydrochloric acid were stirred at 400 rpm for 30min in a polytetrafluoroethylene (PTFE) beaker. Under a 35℃ water bath, 2g of Ti3AlC2 was slowly added, and etching was performed for 24h. After etching, the supernatant was discarded, and the lower precipitate was repeatedly washed to obtain the HF-etched two-dimensional Ti3AlC2 sediment. A scanning electron microscope (SEM) image of the HF-etched two-dimensional Ti3AlC2 sediment is shown below. Figure 1 As shown.

[0047] S2. Take 0.6 g of the HF-etched Ti3AlC2 sediment, add 30 mL of ethanol and 60 mL of TEOS sequentially, and then stir rapidly at 300 rpm for 8 h in a 30℃ water bath. After the reaction is complete, centrifuge and add 50 mL of ammonia water (V) to the solid. 水 V 浓氨水 =2:3), and then reacted at 40℃ for 8h; after the reaction, centrifuged, added 30mL of HF to the solid, and reacted under ultrasonic conditions at 40KHz for 6h; after the reaction, centrifuged, washed with ethanol and water in sequence, and finally vacuum dried at 60℃ for 6h to obtain Ti3AlC2-based MXene nanorolls.

[0048] Figure 3 This is a scanning electron microscope (SEM) image of the Ti3AlC2-based MXene nanorolls prepared in Example 2 of this invention. Figure 3 As shown in the figure, the prepared Ti3C2T x MXene contains a large number of roll-based structures.

[0049] Example 3 A method for large-scale preparation of Ti3AlC2-based MXene nanorolls includes the following steps: S1. 2g of lithium fluoride (LiF) and 40mL of 9M hydrochloric acid were stirred at 400 rpm for 30min in a polytetrafluoroethylene (PTFE) beaker. Under a 35℃ water bath, 2g of Ti3AlC2 was slowly added, and etching was performed for 24h. After etching, the supernatant was discarded, and the lower precipitate was repeatedly washed to obtain the HF-etched two-dimensional Ti3AlC2 sediment. A scanning electron microscope (SEM) image of the HF-etched two-dimensional Ti3AlC2 sediment is shown below. Figure 1 As shown.

[0050] S2. Take 0.6 g of the HF-etched Ti3AlC2 sediment, add 30 mL of ethanol and 50 mL of TEOS sequentially, and then stir rapidly at 300 rpm for 6 h in a 30℃ water bath. After the reaction is complete, centrifuge and add 50 mL of ammonia water (V) to the solid. 水 V 浓氨水=2:3), and then reacted at 60℃ for 5h; after the reaction, centrifuged, added 30mL of HF to the solid, and reacted under ultrasonic conditions at 40KHz for 2h; after the reaction, centrifuged, washed with ethanol and water in sequence, and finally vacuum dried at 60℃ for 6h to obtain Ti3AlC2-based MXene nanorolls.

[0051] Figure 4 This is a scanning electron microscope (SEM) image of the Ti3AlC2-based MXene nanorolls prepared in Example 3 of this invention. Figure 3 As shown in the figure, the prepared Ti3C2T x MXene contains a large number of roll-based structures.

[0052] Comparative Example 1 A method for preparing Ti3AlC2-based MXene materials includes the following steps: S1. 2g of lithium fluoride (LiF) and 40mL of 9M hydrochloric acid were stirred at 400 rpm for 30min in a polytetrafluoroethylene (PTFE) beaker. Under a 35℃ water bath, 2g of Ti3AlC2 was slowly added, and etching was performed for 24h. After etching, the supernatant was discarded, and the lower precipitate was repeatedly washed to obtain the HF-etched two-dimensional Ti3AlC2 sediment. A scanning electron microscope (SEM) image of the HF-etched two-dimensional Ti3AlC2 sediment is shown below. Figure 1 As shown.

[0053] S2. Take 0.6 g of the HF-etched Ti3AlC2 sediment, add 30 mL of ethanol and 10 mL of TEOS sequentially, and then stir rapidly at 300 rpm for 6 h in a 30℃ water bath. After the reaction is complete, centrifuge and add 50 mL of ammonia water (V) to the solid. 水 V 浓氨水 =2:3), and then reacted at 60℃ for 5h; after the reaction, centrifuged, added 30mL of HF to the solid, and reacted under ultrasonic conditions at 40KHz for 2h; after the reaction, centrifuged, washed with ethanol and water in sequence, and finally vacuum dried at 60℃ for 6h to obtain Ti3AlC2-based MXene material.

[0054] Figure 5 This is a scanning electron microscope (SEM) image of the Ti3C2Tx MXene material prepared in Comparative Example 1 of this invention. Figure 5 As shown, no obvious roll-up structure appears in the prepared Ti3C2Tx MXene. This is because the amount of TEOS added is small, resulting in insufficient intercalated SiO2. Subsequently, the mechanical energy released by the microscale explosion effect induced by HF etching of SiO2 under ultrasonic conditions is insufficient to cause the MXene sheets to curl in an oriented manner.

[0055] Comparative Example 2 A method for preparing Ti3AlC2-based MXene materials includes the following steps: S1. 2g of lithium fluoride (LiF) and 40mL of 9M hydrochloric acid were stirred at 400 rpm for 30min in a polytetrafluoroethylene (PTFE) beaker. Under a 35℃ water bath, 2g of Ti3AlC2 was slowly added, and etching was performed for 24h. After etching, the supernatant was discarded, and the lower precipitate was repeatedly washed to obtain the HF-etched two-dimensional Ti3AlC2 sediment. A scanning electron microscope (SEM) image of the HF-etched two-dimensional Ti3AlC2 sediment is shown below. Figure 1 As shown.

[0056] S2. Take 0.6 g of the HF-etched Ti3AlC2 sediment, add 30 mL of ethanol and 80 mL of TEOS sequentially, and then stir rapidly at 300 rpm for 6 h in a 30℃ water bath. After the reaction is complete, centrifuge and add 50 mL of ammonia water (V) to the solid. 水 V 浓氨水 =2:3), and then reacted at 60℃ for 5h; after the reaction, centrifuged, added 30mL of HF to the solid, and reacted under ultrasonic conditions at 40KHz for 2h; after the reaction, centrifuged, washed with ethanol and water in sequence, and finally vacuum dried at 60℃ for 6h to obtain Ti3AlC2-based MXene material.

[0057] Figure 6 This is a scanning electron microscope (SEM) image of the Ti3C2Tx MXene material prepared in Comparative Example 2 of this invention. Figure 5 As shown, no obvious rolled structure appears in the prepared Ti3C2Tx MXene. This is because the large amount of TEOS added generates a large amount of SiO2 on the surface, which not only wastes HF but also cancels out the mechanical energy released by the interlayer microscale explosion, thus preventing the formation of nanorolls.

[0058] It should be noted that when numerical ranges are involved in this invention, it should be understood that both endpoints of each numerical range and any value between the two endpoints can be selected. Since the steps and methods used are the same as in the embodiments, preferred embodiments are described here to avoid redundancy. Although preferred embodiments of the invention have been described, those skilled in the art, once they understand the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this invention.

[0059] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method for large-scale preparation of Ti3AlC2-based MXene nanorolls, characterized in that, Includes the following steps: Using the mud after etching two-dimensional Ti3AlC2 with HF as the raw material for tetraethyl orthosilicate, a hydrolysis reaction was carried out under stirring in a solvent system to generate SiO2 nanoparticles in situ between MXene layers, forming a precursor. Ammonia water is added to the precursor to carry out a dehydration condensation reaction, so that SiO2 nanoparticles are anchored in situ between MXene sheets to form MXene / SiO2 composite material. HF was added to the MXene / SiO2 composite material, and ultrasonic treatment was performed. HF etched the interlayer SiO2 to generate gaseous SiF4, which triggered a microscale explosion effect, causing the MXene sheets to curl up, thus obtaining Ti3AlC2-based MXene nanorolls.

2. The method for large-scale preparation of Ti3AlC2-based MXene nanorolls according to claim 1, characterized in that, The ratio of mud to tetraethyl orthosilicate after HF etching of two-dimensional Ti3AlC2 is 0.6g:30mL~60mL.

3. The method for large-scale preparation of Ti3AlC2-based MXene nanorolls according to claim 1, characterized in that, The ratio of HF-etched two-dimensional Ti3AlC2 sediment to solvent was 0.6g:30mL~60mL, the solvent was ethanol, the hydrolysis reaction temperature was 30℃~50℃, the time was 6h~12h, and the stirring rate was 300rpm.

4. The method for large-scale preparation of Ti3AlC2-based MXene nanorolls according to claim 1, characterized in that, The ratio of mud to ammonia after HF etching of two-dimensional Ti3AlC2 was 0.6g:40mL~60mL, and the concentration of ammonia was 16wt.%~18wt.%.

5. The method for large-scale preparation of Ti3AlC2-based MXene nanorolls according to claim 1, characterized in that, The temperature for the dehydration condensation reaction is 40℃~60℃, and the time is 5h~8h.

6. The method for large-scale preparation of Ti3AlC2-based MXene nanorolls according to claim 1, characterized in that, The ratio of HF to mud after etching two-dimensional Ti3AlC2 was 0.6 g: 30 mL.

7. The method for large-scale preparation of Ti3AlC2-based MXene nanorolls according to claim 1, characterized in that, The ultrasound frequency is 40 kHz, and the duration is 2 to 6 hours.

8. The method for large-scale preparation of Ti3AlC2-based MXene nanorolls according to claim 1, characterized in that, After ultrasonication, centrifugation, washing, and vacuum drying are performed sequentially, with the vacuum drying temperature ranging from 50℃ to 80℃.

9. The method for large-scale preparation of Ti3AlC2-based MXene nanorolls according to claim 1, characterized in that, The method for preparing sediment after HF etching of two-dimensional Ti3AlC2 includes the following steps: Lithium fluoride and hydrochloric acid were mixed and then Ti3AlC2 was added. The mixture was etched in a water bath at 35°C for 24 hours. After the etching was completed, the supernatant was removed to obtain the sludge after HF etching of two-dimensional Ti3AlC2.

10. The method for large-scale preparation of Ti3AlC2-based MXene nanorolls according to claim 9, characterized in that, The ratio of lithium fluoride to hydrochloric acid was 2 g: 40 mL, and the concentration of hydrochloric acid was 9 M; the mass ratio of lithium fluoride to Ti3AlC2 was 1:1.

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