High-intensity ultrasound-assisted rapid preparation and screening of MXene and its derivatives MAM for gas sensing applications

Abstract

The present invention discloses a high-intensity ultrasound-assisted method for the rapid preparation and screening of MXene and its derivatives, MAMs. The method comprises establishing a high-intensity ultrasound environment, preparing an etching solution, performing an etching reaction and treatment, adjusting the centrifugal speed for screening, and finally obtaining the product after vacuum drying. The advantages of this method are that the high-intensity six-sided ultrasound action, combined with stirring, improves the efficiency of MXene preparation. By adjusting the concentration and dosage of the etching agent, a series of MXene and MAM heterostructures can be obtained.

Description

Technical Field

[0001] The present invention relates to a method for preparing MXene nanomaterials, and in particular to a method for high-intensity ultrasound-assisted rapid preparation and screening of MXene and its derivatives for gas sensing applications. Background Art

[0002] Human production and daily life inevitably produce toxic gases. These hidden gaseous pollutants pose multiple risks to humans. Triethylamine, a typical volatile organic compound (VOC), is widely used in chemical synthesis and industrial production. Its volatility and flammability also pose potential environmental hazards. Upon contact, it can irritate the skin and central nervous system and may cause pulmonary edema and headaches.

[0003] Resistive gas sensors are used to detect triethylamine. The performance of triethylamine gas sensors has been improved through noble metal modification / anchoring of metal oxides and the construction of heterostructures. However, these methods do not significantly optimize the sensor's operating temperature. Given the current demand for low carbon, designing low-power, room-temperature sensors is of great significance.

[0004] Two-dimensional transition metal carbides / nitrides (MXenes) have attracted extensive attention due to their unique structure, adsorption properties and rich surface chemical properties. x For example, Ti3AlC2 is obtained by etching its precursor MAX phase, which has been demonstrated to be a promising gas-sensitive material at room temperature.

[0005] Due to the low sensitivity, slow response, monotonic selectivity and slow oxidation of original MXene-based gas sensors, several approaches have been used to improve the performance of MXene-based gas sensors, such as designing mixing strategies, adjusting MXene surface functional groups and introducing mature metal oxide semiconductors to prepare heterostructures.

[0006] However, a current shortcoming is the neglect of the role of MAX and the optimization of etching methods for the MAX phase. The performance and structure of MXene are directly and profoundly influenced by the MAX phase. Due to varying etching processes, the instability of the etching environment, and the diverse methods for handling etched products, it is difficult to obtain MXene with similar properties in a controllable manner across different batches. Immature preparation processes inevitably lead to incompletely etched MXene products. Furthermore, current mainstream methods require a long preparation time, exceeding 24 hours, to obtain high-purity MXene. These conditions make it difficult for researchers to design MXene-based gas sensors that meet the needs of practical applications.

[0007] The high-intensity ultrasonic etching environment reduces the energy required for the reaction and saves reaction time. Ultrasound can effectively delaminate the etched MXene flakes, hindering the re-formation of stable interlayer bonds between MAX and MXene. Surface terminations such as -F, -OH / -O generated on the MXene surface during conventional etching can hinder the etchant from penetrating deeper layers and internally, thereby slowing the reaction time / rate. The cavitation effect of ultrasound can increase mass transfer rates, and the pulsed action can remove reaction byproducts within narrow interlayers and hinder other interlayer chemical bonds, thereby accelerating the etching process. By carefully controlling the various conditions of the etching process, MXene and a unique MAX-MXene intermediate, designated MAM, can be controllably obtained. This rapid preparation method is expected to become a mainstream MXene preparation method, and the resulting MAM nanomaterials with intrinsically heterogeneous structures are expected to become promising substrate materials for nanotechnology applications. Summary of the Invention

[0008] The technical problem to be solved by the present invention is to provide a method for the rapid preparation and screening of MXene and its derivative MAM assisted by high-intensity ultrasound. The high-intensity six-sided ultrasound action combined with the stirring function improves the preparation efficiency of MXene; by adjusting the concentration and dosage of the etchant, a series of MXene and MAM heterostructures are obtained.

[0009] In order to solve the above technical problems, the present invention provides a high-intensity ultrasound-assisted rapid preparation method for MXene, which comprises the following steps:

[0010] Step S1: Setting up a high-intensity ultrasound environment;

[0011] A polytetrafluoroethylene beaker is placed at the center of the bottom of the regular hexagonal prism cavity. A magnetic stirring device with adjustable speed and an adjustable heating device are embedded in the cavity bottom below the polytetrafluoroethylene beaker. A sealed cube is built outside the six sides of the cavity to provide adjustable ultrasonic waves.

[0012] The magnetic stirring speed range is 300-600 rpm, the heating adjustment range is 35-100°C, and the ultrasonic power adjustment range is 288W-720W;

[0013] Step S2: preparation of etching solution;

[0014] The etching solution consists of hydrofluoric acid, hydrochloric acid and deionized water, and the molar ratio of them is: hydrofluoric acid: hydrochloric acid: deionized water = 0.5635:0.24:0.556;

[0015] In a beaker, 20 mL of 49% hydrofluoric acid, 20 mL of 37% hydrochloric acid, and 10 mL of deionized water were mixed at room temperature to obtain an etching solution.

[0016] Step S3: rapid preparation of MXene etching reaction and treatment;

[0017] Add 2g of Ti3AlC2-MAX to 50 mL of etching solution heated to 45°C, adjust the ultrasonic power to 300W-720W, the temperature to 45-55°C, the magnetic stirring speed to 300 rpm, cover the etching environment with a lid and react for 3 hours. After the reaction, centrifuge at 8000 r / min for 9 times, each time for 5 minutes, and finally dry in an oven at 60°C to obtain MXene.

[0018] In step S1, the beaker is 100 mL in size, the regular hexagonal bottom surface of the regular hexagonal cavity has a side length of 10 cm, and the side rectangular side is 20 cm high. The dimensions of the regular hexagonal cavity and the polytetrafluoroethylene beaker are adjusted according to actual production needs. The polytetrafluoroethylene beaker has a built-in polytetrafluoroethylene rotor.

[0019] The hydrofluoric acid in the etching solution of step S2 is generated in situ from fluoride and hydrochloric acid. The etching solution consists of sodium fluoride, hydrochloric acid and deionized water in a molar ratio of sodium fluoride: hydrochloric acid: deionized water = 0.0762:0.48:0.556.

[0020] Specifically, 3.2 g of sodium fluoride, 40 mL of hydrochloric acid (12 mol / L), and 10 mL of deionized water were mixed at room temperature to obtain an etching solution.

[0021] The Ti3AlC2-MAX in step S3 is replaced with V2ALC and Nb2AlC, and the reaction time is increased by 24 hours.

[0022] On the other hand, the present invention provides a method for rapid screening of MXene and its derivatives MAM assisted by high-intensity ultrasound, the screening method comprising the following steps:

[0023] Step P1: preparing etching solution;

[0024] The etching solution is composed of sodium fluoride, hydrochloric acid and deionized water, and the molar ratio of sodium fluoride: hydrochloric acid: deionized water is 0.0191-0.0572: 0.24: 0.556;

[0025] Specifically, 0.8 g, 1.6 g, 2 g, and 2.4 g of sodium fluoride, 20 mL of hydrochloric acid (12 mol / L), and 10 mL of deionized water were mixed at room temperature to obtain an etching solution.

[0026] Alternatively, the etching solution is composed of lithium fluoride, hydrochloric acid and deionized water, and the molar ratio thereof is: lithium fluoride: hydrochloric acid: deionized water = 0.0308-0.0925: 0.24: 0.556;

[0027] Specifically, 0.8 g, 1.6 g, 2 g, and 2.4 g of lithium fluoride, 20 mL of hydrochloric acid (12 mol / L), and 10 mL of deionized water were mixed at room temperature to obtain an etching solution.

[0028] Alternatively, the etching solution is composed of hydrofluoric acid, hydrochloric acid and deionized water, and the molar ratio of them is: hydrofluoric acid: hydrochloric acid: deionized water = 0.0282-0.5635: 0.24: 0.556;

[0029] Specific preparation: Prepare 1 mL, 5 mL, 10 mL, 15 mL, and 20 mL of hydrofluoric acid (49%), 20 mL of hydrochloric acid (12 mol / L), and 10 mL of deionized water at room temperature and mix them to obtain the etching solution;

[0030] The hydrofluoric acid is generated in situ from fluoride and hydrochloric acid, and the fluoride is sodium fluoride, lithium fluoride, iron fluoride, or ammonium fluoride.

[0031] Step P2: Rapid preparation of MXene etching reaction;

[0032] Add 2 g of Ti3AlC2-MAX to 30 mL to 50 mL of etching solution heated to 45 °C, adjust the ultrasonic power to 300 W, the temperature to 45 °C, the magnetic stirring speed to 300 rpm, cover the etching environment with a lid and react for 3 h.

[0033] Step P3: Adjust the centrifugal speed to screen the sample;

[0034] After the etching reaction in step P2, the solution was evenly poured into two centrifuge tubes, and then deionized water was added to each tube to make up the volume to 35 mL. The tubes were centrifuged at 5000 r / min for 6 times, each time for 5 minutes to remove the etching solution. Then, the tubes were centrifuged at different speeds of 1000 r / min to 3000 r / min, each time increasing by 500 rpm, for 1 minute. The black liquid on the upper layer of the two centrifuge tubes was collected. Finally, the six samples, including the bottom precipitate from the last centrifugation, were vacuum dried at 60°C for 8 hours.

[0035] In step P3, the solution in the centrifuge tube was stirred evenly before each centrifugation.

[0036] Step P4: screening the vacuum-dried samples;

[0037] The samples collected in step P1 after reaction treatment with sodium fluoride or lithium fluoride as the fluorine source have obvious differences in macroscopic morphology. The dark black-blue flakes are single-layer MXene, the light-colored mixed blocky MAM nanostructures and the black large blocky MAX are sorted.

[0038] In step P4, the light-colored and dark-colored mixed block-shaped MAM is fully ground to obtain a MAM nanostructure.

[0039] The centrifugal speed in step P3 is determined by increasing the number of centrifugal cycles at the speed depending on the concentration of the upper layer liquid.

[0040] In step P3, the etchant concentration is adjusted to perform classification screening. This is because sodium and lithium ions simultaneously intercalate MXene during ultrasonic-assisted etching. By varying the etchant concentration, different ratios of MXene, MAM, and MAX products are obtained in the product, making the products obtained by this method controllable and screenable.

[0041] On the other hand, the present invention provides the screened MXene derivative MAM for gas sensing applications.

[0042] The superior effects of the present invention are:

[0043] 1) The present invention uses six-sided high-intensity ultrasonic etching to produce a series of MXene and MAM heterostructures by adjusting the concentration of the etchant. Under ultrasonication, the etching time is shortened from the more common 24 / 48 hours to 3 hours, greatly improving the efficiency of MXene preparation.

[0044] 2) By reducing the etching dose, a unique thin block structure with a small surface MXene layer was obtained. The synergistic effect, interfacial contact, and structural defects of the intermediate MAM nanocomposite provide good electrical conductivity and gas sensing properties. The design method and its own properties are regarded as similar to the substrate materials of MAX and MXene, providing ideas for the design and application of other MXene-based nanocomposites. This high-intensity ultrasound-assisted etching method provides a solution for the efficient and controllable preparation of MXene and its derivatives.

[0045] 3) The high-intensity six-sided ultrasonic action of the present invention is supplemented by a stirring function, which enables the ultrasonic intensity to be evenly distributed throughout the solution;

[0046] 4) The products obtained by the present invention can be controlled and screened. Not only can MXene be quickly obtained, but also intermediate products in the process of preparing MXene by MAX etching can be obtained. The intermediate products can be used as sensitive materials for detecting triethylamine gas at room temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0048] Figure 1 is a schematic diagram of a high-intensity ultrasound environment according to an embodiment of the present invention;

[0049] Figure 2 This is the XRD pattern of MXene prepared in Example 1 of the present invention;

[0050] Figure 3 This is a scanning electron microscope (SEM) photograph of the MXene prepared in Example 2 of the present invention;

[0051] Figure 4 The XRD pattern of the MAM prepared in Example 4 of the present invention;

[0052] Figure 5 This is a photo of a sample manually screened in Example 4 of the present invention;

[0053] Figure 6 This is a scanning electron microscope (SEM) photograph of the MXene sample obtained at 1000 rpm in Example 4 of the present invention;

[0054] Figure 7 This is a transmission electron microscope (TEM) photograph of the MAM sample finally precipitated by the centrifugation scheme in Example 4 of the present invention;

[0055] Figure 8 is the baseline fluctuation rate of the MAM2 sample with the best conductivity in Example 1 of the present invention;

[0056] Figure 9 Schematic diagram of the sensitivity of the MAM sensor to different gases in Example 1 of the present invention;

[0057] Description of the numbers in the figure

[0058] 1—regular hexagonal prism cavity; 2—polytetrafluoroethylene beaker. DETAILED DESCRIPTION

[0059] In order to make the technical means, creative features, objectives and effects achieved by the present invention easier to understand, the present invention is further described below with reference to specific illustrations. Example 1:

[0060] The present invention provides a method for rapidly preparing MXene assisted by high-intensity ultrasound, comprising the following steps:

[0061] Step S1: Setting up a high-intensity ultrasound environment;

[0062] like Figure 1 As shown, a 100 mL polytetrafluoroethylene beaker 2 is placed at the bottom center of a regular hexagonal prism cavity 1. A magnetic stirring device with adjustable speed and an adjustable heating device are embedded in the cavity bottom below the polytetrafluoroethylene beaker. A sealed cube is built outside the regular hexagonal prism cavity to provide an adjustable ultrasonic environment.

[0063] The regular hexagonal prism cavity includes a bottom surface and six side surfaces. The bottom surface is a regular hexagon with a side length of 10 cm, and the side surface is a rectangle with a height of 20 cm. The regular hexagonal prism cavity and the cube are both made of stainless steel.

[0064] In Example 1, the magnetic spindle speed was adjusted to 300 rpm, the cavity heating temperature was adjusted to 45-55°C, and the ultrasonic power was adjusted to 300W-720W; the high-intensity six-sided ultrasonic action was supplemented by a stirring function, which achieved a uniform intensity distribution of the ultrasonic waves throughout the solution.

[0065] Step S2: preparation of etching solution;

[0066] In Example 1 of the present invention, a mixed acid etching solution of hydrofluoric acid and hydrochloric acid is prepared;

[0067] The etching solution consists of hydrofluoric acid, hydrochloric acid and deionized water, and the molar ratio of them is: hydrofluoric acid: hydrochloric acid: deionized water = 0.5635:0.24:0.556;

[0068] Prepare an etching solution by mixing 20 mL of 49% hydrofluoric acid, 20 mL of 37% hydrochloric acid, and 10 mL of deionized water in a beaker at room temperature.

[0069] Step S3: Rapid preparation of MXene etching reaction;

[0070] After heating 50 mL of etching solution to 45°C, slowly add 2 g of Ti3AlC2-MAX, adjust the speed of the magnetic stirrer to 300 rpm, the chamber temperature to 45°C, and the ultrasonic power to 300 W; cover the cube with a lid and allow the etching reaction to proceed for 3 h;

[0071] Step S4: rapid preparation of MXene etching and collection;

[0072] After the etching reaction, the tube was centrifuged 9 times at 8000 r / min for 5 min each time. The solution in the centrifuge tube was shaken before each centrifugation. Finally, the MXene was dried in an oven at 60 °C. The XRD pattern of the obtained MXene is shown in the figure. Figure 2 shown.

[0073] The sizes of the regular hexagonal prism cavity and the polytetrafluoroethylene beaker in step S1 are adjusted according to actual production needs. Example 2:

[0074] The high-intensity ultrasonic environment of Example 2 is the same as that of Example 1, except that the etching solution in step S2 is replaced with an etching solution consisting of 3.2 g sodium fluoride, 40 mL hydrochloric acid (12 mol / L), and 10 mL deionized water. The etching reaction of step S3 and the etching treatment and collection of step S4 of Example 1 are repeated, and the scanning electron microscope image of the obtained MXene is shown as follows: Figure 3 shown.

[0075] When Ti3AlC2-MAX in step S3 is replaced with V2ALC or Nb2AlC, the reaction time is relatively increased by 24 hours. Example 3:

[0076] The present invention provides a method for high-intensity ultrasound-assisted rapid screening of MXene and its derivatives MAM, comprising the following steps:

[0077] Step P1: Setting up a high-intensity ultrasound environment is the same as in Example 1;

[0078] Step P2: Preparation of etching solution and etching reaction;

[0079] Prepare an etching solution consisting of 2 g of sodium fluoride, 20 mL of hydrochloric acid (12 mol / L), and 10 mL of deionized water in a beaker and mix them at room temperature.

[0080] Step P3: After the etching solution is heated to 45°C, 2g of Ti3AlC2-MAX is slowly added. The magnetic stirring speed is adjusted to 300 rpm, the chamber temperature is 45°C, and the ultrasonic power is adjusted to 300 W. The cube is covered with a lid and the etching reaction is carried out for 3 hours.

[0081] Step P4: adjusting the centrifugal speed to screen the samples;

[0082] After the reaction in step P3 above, the solution was evenly divided into two centrifuge tubes, and deionized water was added to each of the two tubes to make up the volume to 35 mL. The tubes were centrifuged at 5000 r / min for 6 times, each time for 5 minutes to remove the etching solution. Then, the tubes were centrifuged at different speeds of 1000 r / min to 3000 r / min, each time increasing by 500 rpm, for 1 minute. The black liquid on the upper layer of the two centrifuge tubes was collected. Finally, the six samples, including the bottom precipitate from the last centrifugation, were vacuum dried at 60°C for 8 hours.

[0083] In this step, the solution in the centrifuge tube was manually shaken before each centrifugation;

[0084] Step P5: Manual screening of vacuum-dried samples;

[0085] The samples collected after treatment with sodium fluoride as the fluorine source exhibit distinct macroscopic morphologies: dark blue flakes represent single-layer MXene, while light-colored, dark-colored mixed-block MAM nanostructures and black, large-block MAX are observed. Thorough grinding of the light-colored, dark-colored mixed-block MAM yields MAM nanostructures. Example 4:

[0086] The difference between Example 4 and Example 3 is that the dosage of sodium fluoride in the etchant solution in step P2 is changed to 0.8g, 1.6g, or 2.4g, and steps P3-P5 are repeated to obtain a group of MAM samples. They are named MAM1, MAM2, and MAM3 according to the sodium fluoride dosage from small to large. The XRD patterns of the obtained MAMs are shown in FIG. Figure 4 .

[0087] In Example 4, different ratios of MXene, MAM, and MAX products were obtained in the product by varying the etching dose. The products obtained by this method are controllable and screenable, not only quickly obtaining MXene, but also obtaining the products of the MAX etching process for preparing MXene.

[0088] The samples collected after the reaction treatment in Example 4 have obvious differences in macroscopic morphology. The dark blue flakes are single-layer MXene, the light-colored and dark-colored mixed blocky MAM nanostructures and the black large blocky MAX are sorted. The photos of the screened samples are shown in Figure 2. Figure 5 .

[0089] Sodium fluoride in the etchant solution was replaced with lithium fluoride with a dosage of 0.8 g, 1.6 g, 2 g, or 2.4 g, and steps P3-P5 were repeated to obtain a group of MAM samples.

[0090] In Example 4, the centrifugation conditions were as follows: at different speeds of 1000 r / min to 3000 r / min, with the speed increasing to 1000 rpm, the black liquid on the upper layer of the centrifuge tube was collected after centrifugation for 1 minute, and the four samples including the bottom precipitate of the last centrifugation were collected after freeze-drying. The scanning electron microscope image of the MXene sample obtained by centrifugation at 1000 rpm is shown in FIG. Figure 6 As shown, the TEM of the bottom precipitated MAM is as follows Figure 7 shown.

[0091] The above-mentioned centrifugal speed is determined by increasing the number of centrifugal cycles at the speed depending on the concentration of the supernatant liquid.

[0092] The lower the centrifugal speed, the greater the proportion of MXene in the product; the higher the centrifugal speed, the greater the proportion of MAM in the product. After one centrifugation at 1000 rpm, if the concentration of the supernatant is still high, increase the number of centrifugations at this speed until the concentration of the supernatant decreases.

[0093] By adjusting the ratio of etching dose, a single-layer MXene-loaded MAX phase nanostructure was generated, which was prepared into a gas element with a unique response to triethylamine gas at room temperature.

[0094] The present invention provides a MXene derivative MAM as a gas-sensitive sensing application, comprising the following steps:

[0095] Step X1: Preparation of MAM gas element;

[0096] 5 mg of MAM nanomaterials were ultrasonically dispersed with 100 μl of anhydrous ethanol in a centrifuge tube until fully mixed, and then evenly applied on the electrode. The mixture was placed in a drying oven to dry for 2-4 hours, and then soldered to the circuit board base after cooling. The test was performed after low-temperature aging for 24 hours.

[0097] Step X2: Optimization of MAM gas components;

[0098] The optimal MAM gas element preparation scheme is obtained by the baseline resistance value and stability of the MAM gas element at room temperature; the baseline fluctuation rate of the MAM sample with the best conductivity is as follows Figure 8 As shown in the figure, after a current corresponding to 23°C is given, the resistance value decreases and gradually stabilizes. Figure 8 The fluctuation degree after the resistance is stabilized is shown in the figure;

[0099] Step X3: Gas detection;

[0100] The CGS-8 intelligent gas-sensitive analysis test system was used, with a test current of 36 mA, that is, a fitting temperature of 23°C. Different types of standard gases were injected into the gas distribution box. The concentration of all gases was 50 ppm. The gases were triethylamine, nitrogen dioxide, ammonia, carbon monoxide, ethanol, methanol, n-propanol, and acetone. The resistance changes of the sensors prepared by the MAM gas element after contact with these gases were tested respectively. The results showed that after the injection of other types of gases, the resistance change of the sensor was smaller, indicating that the sensor prepared by the MAM gas element showed good selectivity for triethylamine gas. The selectivity diagram is shown in the figure. Figure 9 As shown in the figure, the MAM sensor has the highest response to triethylamine, a weak response to ammonia and nitrogen dioxide, and no response to other common gases. Therefore, the intermediate product MAM is used as a gas-sensitive material for detecting triethylamine at room temperature.

[0101] The resistance is calculated as follows: (resistance of the sensor in the gas to be measured - resistance of the sensor in air) / resistance of the sensor in air), and the absolute value is taken.

[0102] The basic principles, main features and advantages of the present invention are shown and described above. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention, and such changes and modifications fall within the scope of the invention as claimed.

Claims

1. A method for rapid screening of MXene and its derivatives MAM assisted by high-intensity ultrasound, comprising the following steps: Step P1: Setting up high-intensity ultrasound environment; A polytetrafluoroethylene beaker is placed at the center of the bottom of the regular hexagonal prism cavity. A magnetic stirring device with adjustable speed and an adjustable heating device are embedded in the cavity bottom below the polytetrafluoroethylene beaker. A sealed cube is built outside the six sides of the cavity to provide adjustable ultrasonic waves. Step P2: preparing etching solution; The etching solution is composed of sodium fluoride, hydrochloric acid and deionized water, and the molar ratio of sodium fluoride: hydrochloric acid: deionized water is 0.0191-0.0572: 0.24: 0.556; Step P3: Rapid preparation of MXene etching reaction; Add 2g of Ti3AlC2-MAX into the etching solution heated to 45℃, adjust the ultrasonic power to 300W, the temperature to 45℃, the magnetic stirring speed to 300 rpm, cover the etching environment with a lid and react for 3h; Step P4: adjusting the centrifugal speed to screen the samples; After the etching reaction in step P3, the solution was evenly poured into two centrifuge tubes, and deionized water was added to each of the two centrifuge tubes to make up to at least 35 mL of capacity. The samples were centrifuged at 5000 r / min for 6 times, each time for 5 minutes to remove the etching solution. Then, the samples were centrifuged at different speeds from 1000 r / min to 3000 r / min, each time increasing by 500 rpm, for 1 minute. The black liquid on the upper layer of the two centrifuge tubes was collected. Finally, the six samples, including the bottom precipitate from the last centrifugation, were vacuum dried at 60°C for 8 hours. Step P5: screening the vacuum-dried samples; The dark blue flakes are single-layer MXene, the light dark mixed blocky MAM nanostructures and the black large blocky MAX.

2. The method for high-intensity ultrasound-assisted rapid screening of MXene and its derivatives MAM according to claim 1, characterized in that: The etching solution in step P2 is composed of lithium fluoride, hydrochloric acid and deionized water, and the molar ratio of lithium fluoride: hydrochloric acid: deionized water is 0.0308-0.0925: 0.24: 0.

556.

3. The method for high-intensity ultrasound-assisted rapid screening of MXene and its derivatives MAM according to claim 1, characterized in that: The etching solution in step P2 is composed of hydrofluoric acid, hydrochloric acid and deionized water, and the molar ratio of them is: hydrofluoric acid: hydrochloric acid: deionized water = 0.0282-0.5635: 0.24: 0.

556.

4. The method for high-intensity ultrasound-assisted rapid screening of MXene and its derivatives MAM according to claim 1, characterized in that: In step P4, the solution in the centrifuge tube is stirred evenly before each centrifugation.

5. The method for high-intensity ultrasound-assisted rapid screening of MXene and its derivatives MAM according to claim 1, characterized in that: In step P1, the speed range of magnetic stirring is 300-600 rpm, the adjustment range of heating is 35-100° C., and the adjustment range of ultrasonic power is 288W-720W.

6. A MXene derivative MAM obtained by the screening method according to any one of claims 1 to 5 is used as a gas-sensitive sensor.

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