Method for preparing antioxidant MXene through electrochemical stripping

Abstract

The invention discloses a method for preparing antioxidant MXene through electrochemical stripping, and belongs to the technical field of two-dimensional nano materials. Comprising the following steps: (1) centrifuging a Ti < 3 > C < 2 > T < x > MXene dispersion liquid to obtain a MXene wet solid, and coating the MXene wet solid on two sides of a copper foil; (2) the copper foil coated with the MXene wet solid serves as a cathode, and the cathode and the anode are placed in an electrolytic tank together; and (3) applying a constant voltage for electrolysis, collecting sediments in an electrolytic tank, centrifuging, washing, carrying out suction filtration, and drying to obtain the e-MXene film. The e-MXene prepared by the invention has excellent oxidation resistance and adjustable infrared emissivity, and can adapt to infrared camouflage application under damp and hot conditions.

Description

Technical Field

[0001] The present invention relates to the technical field of two-dimensional nanomaterials, and particularly to a method and application of improving the antioxidant properties of MXene by electrochemical exfoliation. Background Art

[0002] Ti3C2T x MXene is a new type of two-dimensional material composed of transition metal carbides, nitrides or carbonitrides, with a unique layered structure and excellent physical and chemical properties. Its ultra-low infrared emissivity, broad spectrum light absorption and high conductivity make it show great potential in the fields of infrared stealth, thermal energy supplementation, electromagnetic shielding, etc. Compared with traditional metal materials, Ti3C2T x MXene has significant advantages in density and processability, becoming a new generation of multifunctional stealth materials. x MXene has found widespread application in a variety of fields. In batteries and energy storage, its high conductivity and large surface area make it an ideal choice for high-performance electrode materials. In photothermal conversion, MXene's broad-spectrum light absorption enables efficient conversion of solar energy into thermal energy. In electromagnetic shielding, MXene's high conductivity and layered structure enable effective electromagnetic shielding. MXene also shows broad application prospects in soft actuators, sensors, and flexible electronics.

[0003] In recent years, researchers have discovered that Ti3C2T x MXene has unique spectral characteristics in the mid-infrared region, especially the low thermal emissivity associated with the negative dielectric constant. This discovery provides a new theoretical basis for the application of MXene in the fields of infrared stealth and thermal regulation. The low infrared emissivity of MXene enables it to effectively reduce the infrared radiation of the target object, thereby achieving infrared stealth. At the same time, its broad-spectrum light absorption characteristics enable it to absorb and convert external thermal energy to achieve thermal energy replenishment and thermal regulation. Although Ti3C2T x MXene exhibits enormous potential for diverse applications, but its susceptibility to oxidation severely limits its practical application. MXene nanosheets are highly susceptible to oxidation in air, leading to chemical degradation and loss of functional properties. This issue poses challenges to the long-term stability and reliability of MXene materials, particularly in applications requiring long-term exposure to air, such as infrared stealth and wearable devices. Summary of the Invention

[0004] The present invention aims to overcome the shortcomings of MXene, which is susceptible to attack by water and oxygen molecules under hot and humid conditions, generating TiO2 and C, leading to structural destruction and loss of its original excellent properties, reduced antioxidant performance, low preparation efficiency, and low yield. By providing an innovative electrochemical stripping strategy, the present invention addresses these issues by using electrochemical stripping to treat MXene for antioxidant treatment. This method improves the preparation efficiency and yield of MXene and enhances its antioxidant performance during storage, which is of great significance for promoting the application of MXene in the field of infrared camouflage.

[0005] The technical solutions provided by the present invention are as follows:

[0006] The first object of the present invention is to provide a method for preparing antioxidant MXene by electrochemical exfoliation, comprising the following steps:

[0007] (1) Ti3C2T x The MXene dispersion was centrifuged to obtain wet MXene solid, which was then coated on both sides of the copper foil.

[0008] (2) Copper foil coated with wet solid MXene was placed in an electrolytic cell as the cathode together with the anode;

[0009] (3) Applying a constant voltage for electrolysis, collecting the sediment in the electrolytic cell, centrifuging, washing, filtering, and drying to obtain the e-MXene film.

[0010] In one embodiment of the present invention, in step (1), the coating method is a blade coating method.

[0011] In one embodiment of the present invention, in step (2), the anode is a platinum foil.

[0012] In one embodiment of the present invention, in step (2), the electrolyte in the electrolytic cell is an aqueous solution containing one or more of chitosan, lithium chloride, nickel chloride, and tetramethylammonium hydroxide.

[0013] In one embodiment of the present invention, in step (2), the electrolyte is a chitosan aqueous solution, and the chitosan concentration is 0.1-2 wt%.

[0014] Furthermore, the chitosan aqueous solution contains acetic acid, and the acetic acid concentration is 1-2 wt%.

[0015] Furthermore, in the chitosan aqueous solution, the chitosan concentration is 0.3 wt % and the acetic acid concentration is 2 wt %.

[0016] In one embodiment of the present invention, in step (3), the voltage is 5-25V.

[0017] Furthermore, the voltage is 25V.

[0018] In one embodiment of the present invention, in step (3), the electrolysis time is 5-25 minutes.

[0019] Furthermore, the electrolysis time is 25 min.

[0020] In one embodiment of the present invention, in step (3), the MXene after electrolysis is recorded as e-MXene; and the sediment in the electrolytic cell before filtration is recorded as e-MXene dispersion.

[0021] The concentration of the e-MXene dispersion during filtration was 2 mg / mL.

[0022] The second object of the present invention is to provide an antioxidant e-MXene film material prepared by the above method.

[0023] The reaction principle of the present invention is as follows:

[0024] The electric field causes cations to migrate toward the negative electrode (multilayer MXene) and insert into the interlayer spaces of the MXene, forming a protective layer that isolates oxygen. During the cation insertion layer structure, some MXene will fall off the electrode, which is collected during preparation.

[0025] The beneficial technical effects of the present invention are:

[0026] This invention employs an electrochemical exfoliation method, constructs an electrolysis apparatus, and performs antioxidant treatment on MXene. The MXene material produced using a chitosan solution as the electrolyte exhibits excellent antioxidant properties. The process is simple and can be operated continuously, enabling efficient electrochemical exfoliation of MXene in large quantities. The invention also provides the use of the e-MXene material produced by the preparation method described above in infrared camouflage applications.

[0027] The present invention constructs a protective layer on the MXene surface, enhancing its oxidation resistance while also improving stripping efficiency and yield. The introduction of the electrolyte does not significantly affect the infrared stealth and thermal regulation properties of the MXene, thus enabling the integration of multifunctional materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 FIG1 is a diagram of the electrolysis device for the stripping process in Example 1;

[0029] Figure 2 is a scanning electron microscope image of the peeling process in Example 1;

[0030] Figure 3 This is the XRD test pattern of the e-MXene film prepared in Example 1;

[0031] Figure 4This is the Raman test image of the e-MXene film obtained in Example 1;

[0032] Figure 5 This is the zeta potential test diagram of the e-MXene dispersion prepared in Example 1;

[0033] Figure 6 This is the FTIR test image of the e-MXene film prepared in Example 1;

[0034] Figure 7 This is a TEM test image of the e-MXene dispersion prepared in Example 1;

[0035] Figure 8 This is a thermal infrared image of the e-MXene film prepared in Example 1;

[0036] Figure 9 This is the XRD test pattern of the MXene film prepared in Comparative Example 1;

[0037] Figure 10 This is the Raman test image of the MXene film prepared in Comparative Example 1;

[0038] Figure 11 This is the XRD test pattern of the e-MXene-MgCl2 film prepared in Comparative Example 2;

[0039] Figure 12 This is the Raman test image of the e-MXene-MgCl2 film prepared in Comparative Example 2. DETAILED DESCRIPTION

[0040] The present invention will be described in further detail below with reference to specific embodiments.

[0041] Test method:

[0042] (1) Scanning electron microscopy (SEM) was used to image the surface cross-sectional morphology of MXene powder at an accelerating voltage of 5 kV, and the magnification was 10 kx.

[0043] (2) The lattice structure was analyzed by X-ray diffractometer (XRD) with a wide-angle 2θ range of 5-90° and a scan rate of 5° / min. XRD patterns were analyzed using MDI Jade 6 software.

[0044] (3) Confocal Raman microscopy was used to determine the chemical composition of the film sample with an excitation wavelength of 633 nm and a test range of 100-2000 cm -1 Raman spectroscopy imaging of the sample micro-area can visually present the chemical composition distribution of TiO2 and amorphous carbon. The imaging area is 40×40μm at the center of the MXene film. 2 area with a step size of 1 μm.

[0045] (4) Use light scattering particle size and zeta potential instrument to observe the stability of the liquid sample system, and the number of measurements each time should be more than 3 times.

[0046] (5) Qualitative analysis was performed using infrared spectroscopy (FTIR). A small amount of sample was mixed with KBr and ground into a pellet for testing at a wavelength of 400-4000 cm -1 .

[0047] (6) Use field emission transmission electron microscopy to reveal the changes in the microscopic characteristics of the sample over time (morphology, crystal structure, composition, etc.). The sample concentration was diluted to 0.0025 mg·mL -1 The sample was repeatedly dripped onto a 200-mesh micrograting film (Zhongxing Bairui) using a rubber-tipped pipette. After drying, the film was placed in the instrument for testing. The lattice spacing of the sample was measured using GMS 3 software.

[0048] (7) Use a thermal infrared imager to observe the thermal camouflage effect of e-MXene films at different temperatures.

[0049] Example 1

[0050] A method for preparing antioxidant MXene by electrochemical exfoliation comprises the following steps:

[0051] Electrochemical stripping: Ti3C2T prepared by acid etching x The MXene dispersion was centrifuged to obtain multilayer MXene wet solids, which were coated on both sides of the copper foil. The copper foil coated with the MXene wet solids was used as the cathode and the platinum foil as the anode. An electrolysis device was built, and an electrolyte containing 0.3 wt% chitosan and 2 wt% acetic acid was prepared. A voltage of 25 V was applied. After electrolysis for 25 minutes, the sediment was collected and repeatedly centrifuged and washed, and then filtered and dried to obtain the e-MXene film.

[0052] Figure 1 FIG. 4 is a diagram of the electrolysis device for the stripping process of this embodiment. Figure 2 The following are scanning electron microscope images of the stripping process of this embodiment, which are scanning electron microscope images of Ti3AlC2 synthetic powder, multilayer MXene after etching, MXene after electrochemical intercalation, and MXene after ultrasonic treatment. It can be seen that the insertion of electrolyte in the electrolytic stripping process increases the interlayer spacing of MXene, indicating that the electrolyte is successfully intercalated; the e-MXene film prepared in this embodiment was subjected to XRD testing, and the results are as follows Figure 3 As shown. It can be observed that the curves of e-MXene at 0 days, 21 days, and 42 days are consistent, and no lattice diffraction peak of TiO2 appears, indicating that the MXene film after electrochemical exfoliation has not undergone significant oxidation during the storage process. The e-MXene film prepared in this example was subjected to Raman testing, and the results are shown as follows Figure 4As shown. It can be observed that the Raman curves of the e-MXene film at 0 days, 21 days, and 42 days are consistent, indicating that electrochemical exfoliation of chitosan has a protective effect on MXene. The e-MXene dispersion prepared in this example was tested for zeta potential, and the results are shown in Figure 2. Figure 5 As shown in Figure 2, the e-MXene dispersion slowly oxidizes in a water-oxygen environment, and its surface end groups are removed by O atoms to form TiO2, resulting in a decrease in the Zeta potential. Figure 5 The initial Zeta potential of MXene is -32.63mV, which decreases sharply after 7 days and reaches -14.7mV after 30 days. The Zeta potential of e-MXene-25V dispersion is always stable at around -34mV, which fully demonstrates that electrochemical exfoliation improves the antioxidant effect of MXene without affecting the electronegativity of MXene. The e-MXene film prepared in this example was subjected to FTIR test, and the results are as follows: Figure 6 As shown. e-MXene-21day and e-MXene-0day are basically the same, indicating that the MXene obtained by electrochemical exfoliation of chitosan is not easy to oxidize and has structural stability. The e-MXene dispersion prepared in this example was subjected to TEM test, and the results are shown in Figure 2. Figure 7 As shown. e-MXene-21day and e-MXene-0day are basically the same, with no damage or cracks, indicating that no obvious oxidation occurred during the storage process. The e-MXene film prepared in Example 1 was subjected to a thermal camouflage performance test, and the results are shown as follows. Figure 8 As shown in the figure, the 7μm thick e-MXene film covering the object maintains a low radiation temperature as the object's temperature rises in the indoor environment. This indicates that the MXene film has excellent high-temperature thermal camouflage performance.

[0053] Example 2

[0054] A method for preparing antioxidant MXene by electrochemical exfoliation comprises the following steps:

[0055] Electrochemical stripping: Ti3C2T prepared by acid etching x The MXene dispersion was centrifuged to obtain multilayer MXene wet solids, which were coated on both sides of the copper foil. The copper foil coated with the MXene wet solids was used as the cathode and the platinum foil as the anode. An electrolysis device was built, and an electrolyte containing 0.3 wt% chitosan and 2 wt% acetic acid was prepared. A voltage of 15 V was applied. After electrolysis for 15 minutes, the sediment was collected and repeatedly centrifuged and washed, and then filtered and dried to obtain an e-MXene film.

[0056] Example 3

[0057] A method for preparing antioxidant MXene by electrochemical exfoliation comprises the following steps:

[0058] Electrochemical stripping: Ti3C2T prepared by acid etching x The MXene dispersion was centrifuged to obtain multilayer MXene wet solids, which were coated on both sides of the copper foil. The copper foil coated with the MXene wet solids was used as the cathode and the platinum foil as the anode. An electrolysis device was built, and an electrolyte containing 0.7 wt% chitosan and 2 wt% acetic acid was prepared. A voltage of 15 V was applied. After electrolysis for 15 minutes, the sediment was collected and repeatedly centrifuged and washed, and then filtered and dried to obtain an e-MXene film.

[0059] Example 4

[0060] A method for preparing antioxidant MXene by electrochemical exfoliation comprises the following steps:

[0061] Electrochemical stripping: Ti3C2T prepared by acid etching x The MXene dispersion was centrifuged to obtain a multilayer MXene wet solid, which was then coated on both sides of a copper foil. The copper foil coated with the MXene wet solid served as the cathode, and the platinum foil served as the anode. An electrolysis apparatus was constructed using an electrolyte containing 0.3 wt% chitosan and 2 wt% acetic acid. A voltage of 25 V was applied for 15 minutes of electrolysis. Afterwards, the sediment was collected and repeatedly centrifuged and washed. The e-MXene film was then filtered and dried.

[0062] Example 5

[0063] A method for preparing antioxidant MXene by electrochemical exfoliation comprises the following steps:

[0064] Electrochemical stripping: Ti3C2T prepared by acid etching x The MXene dispersion was centrifuged to obtain multilayer MXene wet solids, which were coated on both sides of the copper foil. The copper foil coated with MXene wet solids was used as the cathode and the platinum foil as the anode. An electrolysis device was built, and an electrolyte containing 0.3 wt% chitosan and 2 wt% acetic acid was prepared. A voltage of 15 V was applied. After electrolysis for 25 minutes, the sediment was collected and repeatedly centrifuged and washed, and then filtered and dried to obtain an e-MXene film.

[0065] Comparative Example 1

[0066] The Ti3C2T prepared by acid etching x The MXene dispersion was filtered and dried to obtain a MXene film. The MXene film prepared in this comparative example was subjected to XRD testing, and the results were as follows: Figure 9As shown. It can be seen that the TiO2 peak has appeared on the 21st day, indicating that the MXene is oxidized. The MXene film prepared in this comparative example was subjected to Raman testing, and the results are as follows Figure 10 As shown in Figure 2, it can be seen that the MXene without electrochemical treatment showed a TiO2 peak and amorphous D and G peaks on the 21st day, indicating that the MXene was oxidized.

[0067] Comparative Example 2

[0068] Electrochemical stripping of magnesium chloride: The multilayer MXene prepared by acid etching was coated on both sides of the copper sheet, an electrolysis device was built, an electrolyte containing 0.3wt% magnesium chloride was configured, a voltage of 25V was applied, and after electrolysis for 25 minutes, the sediment was collected and repeatedly centrifuged and washed. The e-MXene-MgCl2 thin film was obtained by filtration and drying. The e-MXene-MgCl2 thin film prepared in this comparative example was subjected to XRD testing, and the results are as follows Figure 11 As shown. It can be seen that the TiO2 peak has appeared on the 21st day, indicating that the MXene is oxidized. The e-MXene-MgCl2 film prepared in this comparative example was subjected to Raman testing, and the results are shown in Figure 2. Figure 12 As shown in Figure 2, it can be seen that the TiO2 peak and amorphous D and G peaks appeared on the 21st day, indicating that MXene was oxidized.

[0069] The embodiments provided above are not intended to limit the scope of the present invention, but are merely preferred embodiments of the present invention. The embodiments are not intended to limit the scope of the present invention, and the steps described are not intended to limit the order of execution. Those skilled in the art may, within the technical scope disclosed in the art, make equivalent substitutions or modifications based on the technical solutions and inventive concepts of the present invention, which shall fall within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing antioxidant MXene by electrochemical exfoliation, characterized in that: The following steps are involved: (1) Ti3C2T x The MXene dispersion was centrifuged to obtain wet MXene solid, which was then coated on both sides of the copper foil. (2) Copper foil coated with wet solid MXene was placed in an electrolytic cell as the cathode together with the anode; (3) Applying a constant voltage for electrolysis, collecting the sediment in the electrolytic cell, centrifuging, washing, filtering, and drying to obtain an e-MXene film.

2. The method according to claim 1, characterized in that In step (1), the coating method is a scraping method.

3. The method according to claim 1, characterized in that In step (2), the anode is platinum foil.

4. The method according to claim 1, wherein In step (2), the electrolyte in the electrolytic cell is an aqueous solution containing one or more of chitosan, lithium chloride, nickel chloride, and tetramethylammonium hydroxide.

5. The method according to claim 1, wherein In step (3), the voltage is 5-25V.

6. The method according to claim 5, characterized in that In step (3), the voltage is 25V.

7. The method according to claim 1, characterized in that In step (3), the electrolysis time is 5-25 min.

8. The method according to claim 7, characterized in that In step (3), the electrolysis time is 25 min.

9. The method according to claim 1, characterized in that In step (3), the concentration of the MXene dispersion during filtration was 2 mg / mL.

10. An antioxidant e-MXene film material prepared by the method according to any one of claims 1 to 9.

Images