Preparation method of flexible sensing material applied to dopamine detection based on Ti3C2Tx / V2CTx synergistic laminated structure design

Abstract

The invention provides a preparation method of a flexible sensing material applied to dopamine detection based on Ti3C2Tx / V2CTx collaborative laminated structure design, and relates to the field of two-dimensional nanomaterials, the preparation method of the flexible composite two-dimensional nanomaterial comprises the following steps: S1, etching a precursor Ti3AlC2; s2, preparation of single layer Ti < 3 > C < 2 > T < x >; s3, the precursor V2AlC is etched; s4, preparation of single layer Ti < 3 > C < 2 > T < x >; preparing an S5Ti < 3 > C < 2 > T < x > / V < 2 > CTx composite material; according to the design, the excellent flexibility and conductivity of Ti3C2Tx and the catalytic characteristic of V2CTx are combined, a high-activity interface is constructed through an interlayer synergistic effect, the obtained flexible sensor shows high sensitivity, a wide linear range and excellent mechanical stability in dopamine detection, the defects that a traditional electrode material is poor in flexibility and insufficient in interface active site are overcome, and the application prospect is wide. According to the preparation process, the risk is reduced by optimizing an etching agent system, the post-treatment process is simplified, and a novel two-dimensional composite platform is provided for the development of the wearable biosensor.

Description

Technical Field

[0001] The present invention relates to the technical field of two-dimensional nanomaterials, specifically a Ti3C2T x and V2CT x Synergistic stacked structural interface design for the preparation of flexible sensing materials for dopamine detection. Background Art

[0002] Currently, electrochemical sensor materials face challenges such as insufficient flexibility and high energy consumption in wearable devices and portable sensor applications, which limit their practical application effects. To solve these problems, this patent proposes an innovative solution by converting Ti3C2T x and V2CT x The two MXene two-dimensional nanosheets were mixed and stirred to prepare a uniform mixed dispersion, and a self-supporting Ti3C2T x / V2CT x Composite membrane.

[0003] Dopamine (DA) is an important neurotransmitter that plays a key role in the central nervous system, kidneys, and cardiovascular system. Abnormal concentrations of DA are closely related to neurological diseases such as Parkinson's disease and Alzheimer's disease. Therefore, the development of a method for rapid and accurate detection of DA is of great significance for disease diagnosis and prevention. Although traditional detection methods such as fluorescence analysis and liquid chromatography are accurate, they have disadvantages such as expensive equipment, complex operation, and long time consumption. In contrast, electrochemical detection has become the mainstream detection method due to its advantages such as simple operation, low cost, and fast response. However, the oxidation products of DA are easily adsorbed on the electrode surface, resulting in a decrease in detection sensitivity. Therefore, the development of highly sensitive and highly selective electrode modification materials is crucial.

[0004] Ti3C2T prepared by this patent x / V2CT x The composite membrane not only exhibits excellent flexibility, adapting to various bending and deformation conditions, but also demonstrates high sensitivity and specific response to DA in electrochemical sensing. MXene materials, due to their high conductivity, rich surface functional groups, and layered structure, can effectively enhance electrode reactivity and charge transfer rates. Furthermore, by optimizing their structure and composition, the composite membrane reduces energy consumption, providing new insights into the development of high-performance, low-energy electrochemical sensor materials.

[0005] This invention has broad application prospects in flexible electronic devices and biosensing. For example, in wearable health monitoring devices, the composite membrane can be used to detect DA concentrations in body fluids in real time, supporting early disease diagnosis. Furthermore, its low energy consumption aligns with the development trend of green environmental protection and is expected to promote the further development and widespread application of electrochemical sensor technology. Summary of the Invention

[0006] In view of the shortcomings of the prior art, the present invention provides a Ti3C2T x / V2CT x The collaborative stacking structure design is used in the preparation method of flexible sensing materials for dopamine detection. In the preparation process of the composite film, Ti3C2T x and V2CT x The synergistic effect of Ti3C2T significantly improves the electrochemical performance of the material. x With high conductivity and abundant surface functional groups, it can provide a large number of active sites and promote the rapid transmission of electrons. x Through its unique layered structure and surface charge characteristics, it is similar to Ti3C2T x Forming a uniform layer-layer stacking structure. This structure not only increases the interlayer spacing, provides a fast mass transfer channel for electrolyte ions, but also stabilizes the interlayer structure of the composite material through electrostatic repulsion. The synergistic effect of the two MXene materials forms a continuous conductive network, significantly improving the efficient transmission capacity of electrons within the film. At the same time, V2CT x The negative surface charge of Ti3C2T x The functional groups of the composite material interact with each other, enhancing the adsorption capacity and electrocatalytic activity of the composite material for dopamine (DA) molecules, thereby improving the sensitivity and selectivity of detection.

[0007] To achieve the above objectives, the present invention is implemented through the following technical solutions: a Ti3C2T x / V2CT x The method for preparing a flexible sensing material for dopamine detection using a collaborative stacking structure design includes the following steps:

[0008] S1. Etching precursor Ti3AlC2

[0009] First, take a water bathtub, add appropriate amount of water, and place it on a heating stirring table to preheat. Then take a clean polytetrafluoroethylene liner with a specification of 100mL, measure 24mL HCl and 6mL HF, 12mL deionized water, and poured into the polytetrafluoroethylene liner (100mL) in succession, covered with the polytetrafluoroethylene liner lid and placed on the stirrer at 400-600rpm and stirred for 20-25min. After the initial stirring is completed, 1g of Ti3AlC2 is weighed and slowly added to the liner in batches, and then the polytetrafluoroethylene liner lid is covered, the water bathtub is sealed with tin foil, and the reaction is carried out at a temperature of 40°C for 24h. During the reaction, hydrofluoric acid etches the Al layer in the precursor Ti3AlC2. After waiting for the reaction to end, the solution in the polytetrafluoroethylene liner is transferred to a centrifuge tube, the speed is set to 3000-5000rpm, and centrifuged for 3-5min. After centrifugation, the supernatant is removed and the above operation is repeated for 7-10 times. The bottom precipitate obtained is multilayer Ti3AlC2 (ML-Ti3AlC2);

[0010] S2. Single-layer Ti3C2T x Preparation

[0011] The prepared ML-Ti3AlC2 was diluted with deionized water and poured into a clean polytetrafluoroethylene liner of 100 mL. Then 2 g of lithium chloride was weighed and added to the liner. The polytetrafluoroethylene liner was covered with a lid and placed on a heated stirring table in a water bath at 40 ° C. The speed was set to 800-1000 rpm and the reaction was carried out for 24 hours. After the reaction was completed, the solution was transferred to a centrifuge tube and centrifuged at 3000-5000 rpm for 3 minutes. After centrifugation, the upper liquid was removed and the above operation was repeated several times. Then, the centrifugation was continued at 2000-3000 rpm for 5 minutes. The above operation was repeated several times and the upper clear liquid was collected and placed in a clean beaker. The collected supernatant was the single-layer Ti3C2T x (FL-Ti3C2T x );

[0012] S3. Etching precursor V2AlC

[0013] First, weigh 1.5g of fluoride and 30mL of deionized water and pour them into a polytetrafluoroethylene liner (100mL), then move it to a fume hood and add 30mL of hydrochloric acid, cover the polytetrafluoroethylene liner with a lid and place it on a stirrer at 400-600rpm and stir for 10-15min. After the initial stirring, weigh a total of 1.5g of MAX phase material V2AlC in small amounts and multiple times and add it to the liner. Continue stirring for 5-10min, then place the polytetrafluoroethylene liner into a reactor and place it in a water heating box. React at a temperature of 100°C for five days. During this process, take out the reactor with cotton gloves and shake it gently several times every day. The fluoride and hydrochloric acid react to produce hydrogen fluoride, which then etches the Al layer in the precursor V2AlC to obtain multilayer V2CT. x (ML-V2CT x );

[0014] S4. Single-layer V2CT x Preparation

[0015] After 5 days of hydrothermal reaction, turn off the power supply, wait for the reactor to cool to room temperature, take it out, collect the solution and centrifuge it. The first time, use a speed of 7000-9000 rpm for 1 minute. After centrifugation, remove the upper liquid, add 30-40 mL of deionized water to the centrifuge tube, shake the centrifuge tube until there is no obvious precipitation at the bottom, and continue to centrifuge at a speed of 5000-6000 rpm for 1 minute. Repeat the above operation and centrifuge 7-10 times. Collect the supernatant and put it into a clean beaker. The supernatant obtained is the monolayer V2CT x (FL-V2CT x );

[0016] S5.Ti3C2T x / V2CT x Preparation of composite materials

[0017] The single layer Ti3C2T prepared and collected in the above steps S2 and S4 x (FL-Ti3C2T x ), single-layer V2CT x (FL-V2CT x ) solution, and then stirred at room temperature for 20 to 25 minutes at a speed of 500 to 600 rpm to obtain Ti3C2T x Nanosheets and V2CT x The mixed dispersion of nanosheets can be obtained by vacuum filtration to obtain a self-supporting Ti3C2T x / V2CT x Composite membrane.

[0018] Preferably, in the step S3, the etchant is a mixed solution of fluoride and hydrochloric acid, wherein the fluoride is any one of sodium fluoride and lithium fluoride, and the mass ratio of the fluoride to the MAX phase material V2AlC is (1-2); the HCl content of the hydrochloric acid in S3 is 36-38%.

[0019] Preferably, in step S1, the etchant is a mixed solution of hydrofluoric acid and hydrochloric acid, and the mass ratio of the mixed acid to the MAX phase material Ti3AlC2 is (1-3); the HF content of the hydrofluoric acid in S1 is 48-51%, and the HCl content of the hydrochloric acid is 36-38%.

[0020] Preferably, the Ti3C2T x With V2CT x The two-dimensional nanosheets are all two-dimensional regular sheet structures, and Ti3C2T x / V2CT x The cross section of the composite film under a scanning electron microscope shows a multi-layer two-dimensional nanosheet stacking structure. x The thickness of the two-dimensional nanosheet is about 1.5 to 30 nm, and the diameter is about 2 to 10 μm. x The thickness of the two-dimensional nanosheet is about 10-100 nm, and the diameter size is about 2-10 μm; Ti3C2T x / V2CT x The interlayer distance of the composite film is about 30-100nm, the diameter size is about 2-10μm, and the Ti3C2T x / V2CT x The composite membrane is mostly a stacked structure of single-layer MXene two-dimensional nanosheets.

[0021] The present invention provides a Ti3C2T x / V2CT x The collaborative stacking structure design is used to prepare a flexible sensing material for dopamine detection. It has the following beneficial effects:

[0022] 1. Ti3C2T x With high conductivity and abundant surface functional groups, it can provide a large number of active sites and promote the rapid transmission of electrons. x Through its unique layered structure and surface charge characteristics, it is similar to Ti3C2T x A uniform layer-by-layer stacking structure is formed, which effectively prevents the restacking problem of MXene sheets. This structure not only increases the interlayer spacing and provides a fast mass transfer channel for electrolyte ions, but also stabilizes the interlayer structure of the composite material through electrostatic repulsion. In addition, V2CT xThe introduction of further enhances the electrical conductivity and mechanical properties of the composite film. The synergistic effect of the two MXene materials forms a continuous conductive network, significantly improving the efficient transmission of electrons within the film.

[0023] 2. The present invention mixes Ti3C2T x and V2CT x The self-supporting Ti3C2T nanosheets were successfully prepared by vacuum filtration technology. x / V2CT x Composite membrane. The composite membrane exhibits excellent flexibility and is suitable for various bending and deformation conditions. At the same time, in electrochemical sensing, the membrane has a remarkable sensitive response to dopamine (DA), supporting precise detection. The optimized composite membrane has superior electrochemical performance while reducing energy consumption, providing new ideas for the development of high-performance, low-energy electrochemical sensor materials. This invention shows broad application prospects in the fields of flexible electronic devices and biosensors, and has the potential to promote the advancement of related technologies. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The MAX phase material of the present invention, single-layer Ti3C2T x Two-dimensional nanosheets, single-layer V2CT x Two-dimensional nanosheets and Ti3C2T x / V2CT x X-ray diffraction patterns of composite materials;

[0025] Figure 2 The MAX phase material of the present invention, single-layer Ti3C2T x Two-dimensional nanosheets, single-layer V2CT x Two-dimensional nanosheets and Ti3C2T x / V2CT x SEM images of the composite materials and Ti3C2T x / V2CT x Energy spectrum of the composite material. DETAILED DESCRIPTION

[0026] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0027] Example 1:

[0028] The embodiment of the present invention provides a Ti3C2Tx / V2CT x The method for preparing a flexible sensing material for dopamine detection using a collaborative stacking structure design includes the following steps:

[0029] S1. Etching precursor Ti3AlC2

[0030] First, take a water bathtub, add an appropriate amount of water, and place it on a heated stirring table to preheat. Then take a clean polytetrafluoroethylene liner with a specification of 100mL, measure 24mL HCl and 6mL HF, and 12mL deionized water respectively, and pour them into the polytetrafluoroethylene liner (100mL) in succession. Cover the polytetrafluoroethylene liner with a lid and place it on a stirrer and stir at 600rpm for 25min. After the initial stirring is completed, weigh 1g Ti3AlC2 and slowly add it to the liner in batches. Then cover the polytetrafluoroethylene liner with a lid, seal the water bathtub with tin foil, and react at a temperature of 40°C for 24h. During the reaction, hydrofluoric acid etches the Al layer in the precursor Ti3AlC2. After waiting for the reaction to end, the solution in the polytetrafluoroethylene liner is transferred to a centrifuge tube, set the speed to 5000rpm, centrifuge for 5min, remove the supernatant after centrifugation, repeat the above operation and centrifuge 10 times. The bottom precipitate obtained is multilayer Ti3AlC2 (ML-Ti3AlC2);

[0031] S2. Single-layer Ti3C2T x Preparation

[0032] The prepared ML-Ti3AlC2 was diluted with deionized water and poured into a clean polytetrafluoroethylene liner of 100 mL. Then 2 g of lithium chloride was weighed and added to the liner. The polytetrafluoroethylene liner was covered with a lid and placed on a heated stirring table in a water bath at 40 ° C. The speed was set to 1000 rpm and the reaction was carried out for 24 hours. After the reaction was completed, the solution was transferred to a centrifuge tube and centrifuged at 5000 rpm for 3 minutes. After centrifugation, the upper liquid was removed and the above operation was repeated several times. Then, the centrifugation was continued at 3000 rpm for 5 minutes. The above operation was repeated several times and the upper clear liquid was collected and placed in a clean beaker. The collected supernatant was the single-layer Ti3C2T x (FL-Ti3C2T x );

[0033] S3. Etching precursor V2AlC

[0034] First, weigh 1.5g of fluoride and 30mL of deionized water and pour them into a polytetrafluoroethylene liner (100mL), then move it to a fume hood and add 30mL of hydrochloric acid. Cover the polytetrafluoroethylene liner with a lid and place it on a stirrer at 600rpm and stir for 15min. After the initial stirring, weigh a total of 1.5g of MAX phase material V2AlC in small amounts and multiple times and add it to the liner. Continue stirring for 10min, then place the polytetrafluoroethylene liner into a reactor and place it in a water heating box. React at a temperature of 100°C for five days. During this process, take out the reactor with cotton gloves and shake it gently several times every day. The fluoride and hydrochloric acid react to produce hydrogen fluoride, which then etches the Al layer in the precursor V2AlC to obtain multilayer V2CT. x (ML-V2CT x );

[0035] S4. Single-layer V2CT x Preparation

[0036] After 5 days of hydrothermal reaction, turn off the power supply, wait for the reactor to cool to room temperature, take it out, collect the solution and centrifuge it. The first time, use 9000 rpm to centrifuge for 1 minute. After centrifugation, remove the upper liquid, add 40 mL of deionized water to the centrifuge tube, shake the centrifuge tube until there is no obvious precipitation at the bottom, and continue to centrifuge at 6000 rpm for 1 minute. Repeat the above operation and centrifuge 10 times. Collect the supernatant and put it into a clean beaker. The supernatant obtained is the monolayer V2CT x (FL-V2CT x );

[0037] S5.Ti3C2T x / V2CT x Preparation of composite materials

[0038] The single layer Ti3C2T prepared and collected in the above steps S2 and S4 x (FL-Ti3C2T x ), single-layer V2CT x (FL-V2CT x ) solution, 5 mL each, and then stirred at room temperature at a speed of 600 rpm for 25 min to obtain Ti3C2T x Nanosheets and V2CT x The mixed dispersion of nanosheets can be obtained by vacuum filtration to obtain a self-supporting Ti3C2T x / V2CT x Composite membrane.

[0039] In step S3, the etchant is a mixed solution of fluoride and hydrochloric acid, wherein the fluoride is any one of sodium fluoride and lithium fluoride, and the mass ratio of the fluoride to the MAX phase material V2AlC is 2:1; the HCl content of the hydrochloric acid in S3 is 38%.

[0040] In step S1, the etchant is a mixed solution of hydrofluoric acid and hydrochloric acid, and the mass ratio of the mixed acid to the MAX phase material Ti3AlC2 is 3:1; the HF content of the hydrofluoric acid in S1 is 51%, and the HCl content of the hydrochloric acid is 38%.

[0041] Ti3C2T x With V2CT x The two-dimensional nanosheets are all two-dimensional regular sheet structures, and Ti3C2T x / V2CT x The cross section of the composite film under a scanning electron microscope shows a multi-layer two-dimensional nanosheet stacking structure. x The thickness of the two-dimensional nanosheet is about 30nm, and the diameter is about 10μm; the single-layer Ti3C2T x The thickness of the two-dimensional nanosheet is about 30nm, and the diameter is about 10μm; Ti3C2T x / V2CT x The interlayer distance of the composite film is about 100nm, the diameter size is about 10μm, and the Ti3C2T x / V2CT x The composite membrane is mostly a stacked structure of single-layer MXene two-dimensional nanosheets.

[0042] Figure 1 MAX phase material, single layer Ti3C2T x Two-dimensional nanosheets, single-layer V2CT x Two-dimensional nanosheets and Ti3C2T x / V2CT x X-ray diffraction spectrum of the composite film, from Figure 1 As can be seen in a, V2CT x Compared with V2AlC, the unique peaks in the pattern corresponding to the 002 and 103 crystal planes are the key to the successful preparation of V2CT. x Evidence of V2CT obtained by etching x The diffraction peak angle is smaller than that of V2AlC, and the overall shift is to the left. The 002 peak shifts from 2θ=13.66° in V2AlC to V2CT. x The 2θ of V2CT is 9.05°. This is because after the Al layer is corroded, some atomic groups are introduced between the layers, which increases the interlayer spacing. xThe 103 crystal plane almost disappears, which is attributed to the greatly weakened characteristic peak of Al in V2AlC, indicating that the interplanar spacing increases and the Al layer is corroded and peeled off, which means that several layers of V2CT are obtained. x .

[0043] exist Figure 1 b, FL-V2CT x Only the extremely strong MXene characteristic diffraction 002 peak appears, and the characteristic peak related to the MAX phase material V2AlC does not appear, which is consistent with the FL-V2CT x logo.

[0044] from Figure 1 As can be seen from c, Ti3C2T x Compared with Ti3AlC2, the unique peaks corresponding to 002 and 014 crystal planes in the pattern are the result of successful preparation of Ti3C2T x Evidence. Ti3C2T obtained by etching x The diffraction peak angle is smaller than that of Ti3AlC2, and the overall shift is to the left. The 002 peak shifts from 2θ=9.58° in V2AlC to V2CT x The 2θ value is 5.85°. This is because after the Al layer is etched away, some atomic groups are introduced between the layers, increasing the interlayer spacing. The 014 crystal plane of Ti3AlC2 almost disappears, which is attributed to the greatly weakened characteristic peak of Al in Ti3AlC2. This indicates that the interplanar spacing has increased and the Al layer has been stripped away by corrosion.

[0045] exist Figure 1 d, FL-Ti3C2T x Only the extremely strong MXene characteristic diffraction 002 peak appears, and the characteristic peak related to the MAX phase material Ti3AlC2 does not appear, which is consistent with the FL-Ti3C2T x logo.

[0046] exist Figure 1 e and Figure 1 f, Ti3C2T x / V2CT x The composite film shows two MXene characteristic diffraction 002 peaks at the same time, which is consistent with the Ti3C2T x and V2CT x Therefore, the characterization of these characteristic peaks is a sign of the successful preparation of the product.

[0047] The single-layer Ti3C2T prepared by the present invention x and single-layer V2CT x There is no obvious diffraction peak of MAX phase in the two-dimensional nanosheets, indicating that the Al layer elements in the MAX phase have been fully etched. x and V2CTx The synergistic stacking structure also appears Ti3C2T x and V2CT x The diffraction peaks are consistent with those of composite materials.

[0048] Figure 2 MAX phase material, single layer Ti3C2T x Two-dimensional nanosheets, single-layer V2CT x Two-dimensional nanosheets and Ti3C2T x / V2CT x SEM images of the composite materials and Ti3C2T x / V2CT x Energy spectrum diagram, Figure a shows a single layer V2CT x Two-dimensional nanosheets, Figure b shows a single layer of Ti3C2T x Two-dimensional nanosheets, Ti3C2T x With high conductivity and abundant surface functional groups, it can provide a large number of active sites and promote the rapid transmission of electrons. x Through its unique layered structure and surface charge characteristics, it is similar to Ti3C2T x The formation of a uniform layer-layer stacking structure provides a fast mass transfer channel for electrolyte ions and stabilizes the interlayer structure of the composite material through electrostatic repulsion. In addition, V2CT x The introduction of further enhances the electrical conductivity and mechanical properties of the composite film. Figure cd shows Ti3C2T x / V2CT x A partial magnified image of the composite material. The synergistic effect of the two MXene materials forms a continuous conductive network, significantly improving the efficient transmission of electrons within the film. Figure 2 As shown in e, Ti3C2T x With V2CT x A uniform layer-layer stacking structure is formed. The Ti3C2T x / V2CT x The element distribution of Ti and V in the sample, such as Figure 2 f. The uniform distribution of Ti and V indicates that Ti3C2T x With V2CT x The nanosheets are evenly distributed, confirming that Ti3C2T x With V2CT x layer-by-layer stacking structure.

[0049] Example 2:

[0050] The embodiment of the present invention provides a Ti3C2T x / V2CT xThe method for preparing a flexible sensing material for dopamine detection using a collaborative stacking structure design includes the following steps:

[0051] S1. Etching precursor Ti3AlC2

[0052] First, take a water bathtub, add an appropriate amount of water, and place it on a heated stirring table to preheat. Then take a clean 100mL polytetrafluoroethylene liner, measure 24ml HCl, 6ml HF, and 12ml deionized water, and pour them into the polytetrafluoroethylene liner (100mL) in turn. Cover the polytetrafluoroethylene liner with a lid and place it on a stirrer at 400rpm for 20min. After the initial stirring is completed, weigh 1g Ti3AlC2 and slowly add it to the liner in batches. Then cover the polytetrafluoroethylene liner with a lid, seal the water bathtub with tin foil, and react at 40℃ for 24h. During the reaction, hydrofluoric acid etches the Al layer in the precursor Ti3AlC2. After the reaction is completed, transfer the solution in the polytetrafluoroethylene liner into a centrifuge tube, set the speed to 3000rpm, and centrifuge for 3-5min. After centrifugation, remove the supernatant. Repeat the above operation and centrifuge 7 times. The bottom precipitate obtained is multilayer Ti3AlC2 (ML-Ti3AlC2).

[0053] S2. Single-layer Ti3C2T x Preparation

[0054] The prepared ML-Ti3AlC2 was diluted with deionized water and poured into a clean polytetrafluoroethylene liner of 100 mL. Then 2 g of lithium chloride was weighed and added to the liner. The polytetrafluoroethylene liner was covered with a lid and placed on a heated stirring table in a water bath at 40 ° C. The speed was set to 800 rpm and the reaction was carried out for 24 hours. After the reaction was completed, the solution was transferred to a centrifuge tube and centrifuged at 3000 rpm for 3 minutes. After centrifugation, the upper liquid was removed and the above operation was repeated for several times. Then, the centrifugation was continued at 2000 rpm for 5 minutes. The above operation was repeated for several times, and the upper clear liquid was collected and placed in a clean beaker. The collected supernatant was the single-layer Ti3C2T x (FL-Ti3C2T x ).

[0055] S3. Etching precursor V2AlC

[0056] First, weigh 1.5g of fluoride and 30mL of deionized water and pour them into a polytetrafluoroethylene liner (100mL), then move it to a fume hood and add 30mL of hydrochloric acid. Cover the polytetrafluoroethylene liner with a lid and place it on a stirrer at 400rpm and stir for 10min. After the initial stirring, weigh a total of 1.5g of MAX phase material V2AlC in small amounts and multiple times and add it to the liner. Continue stirring for 5min, then place the polytetrafluoroethylene liner into a reactor and place it in a water heating box. React at a temperature of 100°C for five days. During this process, take out the reactor with cotton gloves and shake it gently several times every day. The fluoride and hydrochloric acid react to produce hydrogen fluoride, which then etches the Al layer in the precursor V2AlC to obtain multilayer V2CT. x (ML-V2CT x ).

[0057] S4. Single-layer V2CT x Preparation

[0058] After 5 days of hydrothermal reaction, turn off the power supply, wait for the reactor to cool to room temperature, take it out, collect the solution and centrifuge it. The first time, use 7000 rpm to centrifuge for 1 minute. After centrifugation, remove the upper liquid, add 30 mL of deionized water to the centrifuge tube, shake the centrifuge tube until there is no obvious precipitation at the bottom, and continue to centrifuge at 5000 rpm for 1 minute. Repeat the above operation and centrifuge for 7 times. Collect the supernatant and put it into a clean beaker. The supernatant obtained is the monolayer V2CT x (FL-V2CT x );

[0059] S5.Ti3C2T x / V2CT x Preparation of composite materials

[0060] The single layer Ti3C2T prepared and collected in the above steps S2 and S4 x (FL-Ti3C2T x ), single-layer V2CT x (FL-V2CT x ) solution, 5 ml each, and then stirred at room temperature at a speed of 500 rpm for 20 min to obtain Ti3C2T x Nanosheets and V2CT x The mixed dispersion of nanosheets can be obtained by vacuum filtration to obtain a self-supporting Ti3C2T x / V2CT x Composite membrane.

[0061] In step S3, the etchant is a mixed solution of fluoride and hydrochloric acid, wherein the fluoride is any one of sodium fluoride and lithium fluoride, and the mass ratio of the fluoride to the MAX phase material V2AlC is 1:1; the HCl content of the hydrochloric acid in S3 is 36%.

[0062] In step S1, the etchant is a mixed solution of hydrofluoric acid and hydrochloric acid, and the mass ratio of the mixed acid to the MAX phase material Ti3AlC2 is 1:1; the HF content of the hydrofluoric acid in S1 is 48%, and the HCl content of the hydrochloric acid is 36%.

[0063] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A Ti3C2T based x / V2CT x A method for preparing a flexible sensing material for dopamine detection using a collaborative stacking structure design is characterized by: The following steps are involved: S1. Etching precursor Ti3AlC2 First, take a water bathtub, add appropriate amount of water, and place it on a heated stirring table to preheat. Then, take a clean 100mL polytetrafluoroethylene liner, measure 24mL HCl, 6mL HF, and 12mL deionized water, and pour them into the polytetrafluoroethylene liner (100mL) in sequence. Cover the polytetrafluoroethylene liner with a lid and place it on a stirrer at 400-600rpm for 20-25min. After the initial stirring is completed, weigh 1g Ti3AlC2 is slowly added to the liner in batches, and then the polytetrafluoroethylene liner is covered with a lid, and the water bath is sealed with tin foil. The reaction is carried out at a temperature of 40°C for 24 hours. During the reaction, hydrofluoric acid etches the Al layer in the precursor Ti3AlC2. After the reaction is completed, the solution in the polytetrafluoroethylene liner is transferred to a centrifuge tube, the speed is set to 3000-5000 rpm, and centrifuged for 3-5 minutes. After centrifugation, the supernatant is removed. The above operation is repeated for 7-10 times, and the bottom precipitate obtained is multilayer Ti3AlC2 (ML-Ti3AlC2); S2. Single-layer Ti3C2T x Preparation The prepared ML-Ti3AlC2 was diluted with deionized water and poured into a clean polytetrafluoroethylene liner of 100 mL. Then 2 g of lithium chloride was weighed and added to the liner. The polytetrafluoroethylene liner was covered with a lid and placed on a heated stirring table in a water bath at 40 ° C. The speed was set to 800-1000 rpm and the reaction was carried out for 24 hours. After the reaction was completed, the solution was transferred to a centrifuge tube and centrifuged at 3000-5000 rpm for 3 minutes. After centrifugation, the upper liquid was removed and the above operation was repeated several times. Then, the centrifugation was continued at 2000-3000 rpm for 5 minutes. The above operation was repeated several times and the upper clear liquid was collected and placed in a clean beaker. The collected supernatant was the single-layer Ti3C2T x (FL-Ti3C2T x ); S3. Etching precursor V2AlC First, weigh 1.5g of fluoride and 30mL of deionized water and pour them into a polytetrafluoroethylene liner (100mL), then move it to a fume hood and add 30mL of hydrochloric acid, cover the polytetrafluoroethylene liner with a lid and place it on a stirrer at 400-600rpm and stir for 10-15min. After the initial stirring, weigh a total of 1.5g of MAX phase material V2AlC in small amounts and multiple times and add it to the liner. Continue stirring for 5-10min, then place the polytetrafluoroethylene liner into a reactor and place it in a water heating box. React at a temperature of 100°C for five days. During this process, take out the reactor with cotton gloves and shake it gently several times every day. The fluoride and hydrochloric acid react to produce hydrogen fluoride, which then etches the Al layer in the precursor V2AlC to obtain multilayer V2CT. x (ML-V2CT x ); S4. Single-layer V2CT x Preparation After 5 days of hydrothermal reaction, turn off the power supply, wait for the reactor to cool to room temperature, take it out, collect the solution and centrifuge it. The first time, use a speed of 7000-9000 rpm for 1 minute. After centrifugation, remove the upper liquid, add 30-40 mL of deionized water to the centrifuge tube, shake the centrifuge tube until there is no obvious precipitation at the bottom, and continue to centrifuge at a speed of 5000-6000 rpm for 1 minute. Repeat the above operation and centrifuge 7-10 times. Collect the supernatant and put it into a clean beaker. The supernatant obtained is the monolayer V2CT x (FL-V2CT x ); S5.Ti3C2T x / V2CT x Preparation of composite materials The single layer Ti3C2T prepared and collected in the above steps S2 and S4 x (FL-Ti3C2T x ), single-layer V2CT x (FL-V2CT x ) solution, and then stirred at room temperature for 20 to 25 minutes at a speed of 500 to 600 rpm to obtain Ti3C2T x Nanosheets and V2CT x The mixed dispersion of nanosheets can be obtained by vacuum filtration to obtain a self-supporting Ti3C2T x / V2CT x Composite membrane.

2. A Ti3C2T based on claim 1 x / V2CT x A method for preparing a flexible sensing material for dopamine detection using a collaborative stacking structure design is characterized by: In the step S3, the etchant is a mixed solution of fluoride and hydrochloric acid, wherein the fluoride is any one of sodium fluoride and lithium fluoride, and the mass ratio of the fluoride to the MAX phase material V2AlC is (1-2); the HCl content of the hydrochloric acid in S3 is 36-38%.

3. A Ti3C2T based on claim 1 x / V2CT x A method for preparing a flexible sensing material for dopamine detection using a collaborative stacking structure design is characterized by: In the step S1, the etchant is a mixed solution of hydrofluoric acid and hydrochloric acid, and the mass ratio of the mixed acid to the MAX phase material Ti3AlC2 is (1-3); the HF content of the hydrofluoric acid in S1 is 48-51%, and the HCl content of the hydrochloric acid is 36-38%.

4. A Ti3C2T based on claim 1 x / V2CT x A method for preparing a flexible sensing material for dopamine detection using a collaborative stacking structure design is characterized by: The Ti3C2T x With V2CT x The two-dimensional nanosheets are all two-dimensional regular sheet structures, and Ti3C2T x / V2CT x The cross section of the composite film under scanning electron microscopy shows a multi-layer two-dimensional nanosheet stacking structure. x The thickness of the two-dimensional nanosheet is about 1.5 to 30 nm, and the diameter is about 2 to 10 μm. x The thickness of the two-dimensional nanosheet is about 10-100 nm, and the diameter size is about 2-10 μm; Ti3C2T x / V2CT x The interlayer distance of the composite film is about 30-100nm, the diameter size is about 2-10μm, and the Ti3C2T x / V2CT x The composite membrane is mostly a stacked structure of single-layer MXene two-dimensional nanosheets.

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