Ti3C2TxMXene-graphene oxide materials, their preparation methods, applications, and detection devices

Abstract

This invention provides a Ti3C2T x MXene-graphene oxide material, its preparation method, application, and detection device, wherein the preparation method includes: mixing Ti3C2T x The first mixture obtained from MXene dispersion and graphene oxide dispersion is subjected to a first stirring, followed by the addition of a precipitant for coagulation and a second stirring in a protective atmosphere. The resulting second mixture is then vacuum filtered and dried to obtain the Ti3C2T. x MXene-graphene oxide material. This invention utilizes separately dispersed Ti3C2T... x MXene dispersion and graphene oxide dispersion are subjected to a first stirring, coagulation, a second stirring, and vacuum filtration, followed by drying to obtain Ti3C2T with excellent performance, a micro-layered structure, and superior conductivity. x The MXene-graphene oxide material has the advantages of simple, efficient and low-cost preparation process. The pressure sensor obtained by this invention has good applicability to skin and substrate.

Description

Technical Field

[0001] This invention relates to the field of sensor technology, and more particularly to Ti3C2T. x MXene (graphene oxide) materials, their preparation methods, applications, and detection devices. Background Technology

[0002] Flexible wearable sensors are widely used for real-time monitoring of human physiological parameters and various movement states due to their comfort, breathability, non-invasiveness, and good skin fit. With the rapid development of wearable electronic devices and artificial intelligence technology, the potential applications of flexible pressure sensors in healthcare monitoring, motion detection, intelligent robots, and highly advanced human robots have attracted considerable attention. Meanwhile, as a key aspect of medical diagnosis, real-time monitoring and data storage of pulse, blood pressure, and heart rate are equally crucial.

[0003] MXene is a two-dimensional material composed of carbides, nitrides, and metallic transition carbonitrides, each a few atomic layers thick. MXene is considered a viable conductive electrode material. It is finding increasingly widespread applications in supercapacitors, batteries, electromagnetic interference shielding, and other materials. Due to the presence of hydroxyl groups on its surface and oxygen groups at its terminals, MXene possesses unique properties such as high conductivity, high specific surface area, and good hydrophilicity, making it an ideal choice for manufacturing flexible pressure sensors.

[0004] Like MXene, graphene is an innovative carbon material with excellent electrical conductivity, and it has been one of the most widely studied materials in recent years. Graphene oxide is an important derivative of graphene-based materials. The introduction of oxygen-containing groups not only makes its chemical properties more stable, but also increases the number of active sites for surface modification and a relatively large specific surface area. Therefore, graphene oxide has also become another research hotspot.

[0005] Two-dimensional nanomaterials (MXene, graphene, etc.) possess excellent physical and chemical properties due to their size effect, and currently show great promise for applications in many fields. To effectively utilize the superior nanoscale properties of MXene and graphene in relevant fields, assembling micro / nanosheets into macroscopic functional structures (such as one-dimensional fibers and two-dimensional films) using emerging assembly techniques is a highly effective method. Rational structural design and morphology control of two-dimensional nanomaterials can not only better utilize their excellent electrochemical properties but also develop new functional properties, expanding their application range.

[0006] Therefore, it is very important to study the assembly strategies of two-dimensional nanomaterials and use them to manufacture macroscopic functional materials so as to realize the practical application of two-dimensional nanomaterials. Summary of the Invention

[0007] In view of the problems existing in the prior art, the present invention provides Ti3C2T x MXene-graphene oxide material, its preparation method, application and detection device, and Ti3C2T x MXene-graphene oxide material possesses both a layered structure and excellent conductivity. Through its tightly composite layered structure, it mitigates sensor failure caused by MXene's hygroscopic nature and instability due to numerous defects within graphene, while simultaneously improving the stability of the two-dimensional material. The composite of two different two-dimensional conductive materials results in fewer mutually repelling groups between layers, weaker repulsion, and more flexible contraction under pressure, leading to a shorter response time. This is significant for improving sensitivity, stability, and pressure detection range.

[0008] To achieve this objective, the present invention adopts the following technical solution:

[0009] In a first aspect, the present invention provides a Ti3C2T x A method for preparing MXene-graphene oxide materials, the method comprising:

[0010] Hybrid Ti3C2T x The first mixture obtained from MXene dispersion and graphene oxide dispersion is subjected to a first stirring, followed by the addition of a precipitant for coagulation and a second stirring in a protective atmosphere. The resulting second mixture is then vacuum filtered and dried to obtain the Ti3C2T. x MXene-graphene oxide material.

[0011] This invention uses Ti3C2T x The combination of MXene dispersion and graphene oxide dispersion using simple vacuum filtration offers the advantage of simple operation steps and can produce a layered structure. Furthermore, the tight composite layered structure improves the sensor failure caused by the hygroscopic nature of MXene and the instability caused by numerous defects inside graphene.

[0012] It is worth noting that Ti3C2T x Both MXene and graphene oxide are negatively charged. When their dispersions are mixed, a repulsive effect occurs, leading to a dissimilar reaction between Ti3C2T and MXene. x The large spacing between MXene and graphene oxide makes it difficult to obtain an alternating layered structure even after vacuum filtration, hindering the production of layered thin film products. Therefore, a precipitant is needed for coagulation, which essentially involves bringing Ti3C2T closer together. xThe spacing between MXene and graphene oxide was not completely precipitated during the second stirring process; after vacuum filtration, Ti3C2T was formed. x A layered film of alternating layers of MXene and graphene oxide was obtained to produce Ti3C2T. x MXene-graphene oxide material. Furthermore, the initial stirring in this invention promotes the formation of Ti3C2T. x MXene dispersion and graphene oxide dispersion were mixed to obtain Ti3C2T. x The product has a more uniform distribution of MXene and graphene oxide, while Ti3C2T is produced after the first stirring. x The repulsive double-layer effect between MXene and graphene oxide has already formed, and it is difficult to disrupt the steady state between them even after the addition of a precipitant. The Ti3C2T structure can be broken through the combined action of a second stirring process and the precipitant. x The repulsive steady state between MXene and graphene oxide shortens the Ti3C2T phase. x The spacing between MXene and graphene oxide achieves a coagulation effect, which helps to obtain thin film products through subsequent vacuum filtration.

[0013] Preferably, the Ti3C2T x Ti3C2T in MXene dispersion and graphene oxide dispersion x The mass ratio of MXene to graphene oxide is 2 to 5:1, for example, it can be 2:1, 2.4:1, 2.7:1, 3:1, 3.4:1, 3.7:1, 4:1, 4.4:1, 4.7:1 or 5:1, etc.

[0014] Preferably, the Ti3C2T x Ti3C2T in MXene dispersion x The concentration of MXene is 0.5–1.5 g / L.

[0015] It is worth noting that this invention aims to obtain high-performance Ti3C2T through vacuum filtration. x MXene-graphene oxide material requires the addition of Ti3C2T x Controlling the mass ratio of MXene to graphene oxide within the above range is more conducive to obtaining thin film products with alternating layers of the two.

[0016] The Ti3C2T described in this invention x Ti3C2T in MXene dispersion x The T in MXene indicates the part replaced by -F or -OH, and there is no special limitation on the subscript x, which is a common expression in the art.

[0017] Preferably, the concentration of graphene oxide in the graphene oxide dispersion is 0.5 to 1.5 g / L, for example, it can be 0.5 g / L, 0.7 g / L, 0.8 g / L, 0.9 g / L, 1 g / L, 1.1 g / L, 1.2 g / L, 1.3 g / L, 1.4 g / L or 1.5 g / L, etc.

[0018] It is worth noting that, since concentration has a significant impact on the performance of products obtained from coagulation and vacuum filtration, when the concentration is too high, it can easily lead to direct coagulation to form a three-dimensional solid material, making it impossible to obtain a thin film of Ti3C2T. x MXene-graphene oxide material; when the concentration is too low, it is difficult for the two to combine and form a thin film, therefore this invention also needs to control the concentration of Ti3C2T. x Ti3C2T in MXene dispersion x The concentration of MXene and the concentration of graphene oxide in the graphene oxide dispersion can lead to better preparation of thin film products.

[0019] Preferably, the protective atmosphere includes a nitrogen atmosphere and / or a helium atmosphere.

[0020] Preferably, the rotation speed of the first stirring is 400 to 800 rpm, for example, it can be 400 rpm, 445 rpm, 489 rpm, 534 rpm, 578 rpm, 623 rpm, 667 rpm, 712 rpm, 756 rpm or 800 rpm.

[0021] Preferably, the first stirring time is 25 to 40 minutes, for example, it can be 25 minutes, 27 minutes, 29 minutes, 30 minutes, 32 minutes, 34 minutes, 35 minutes, 37 minutes, 39 minutes or 40 minutes.

[0022] Preferably, the temperature of the first stirring is room temperature.

[0023] Preferably, the precipitant comprises an acid, preferably hydrochloric acid.

[0024] The precipitant described in this invention is an acid, which provides protons, thereby bringing Ti3C2T closer together. x The distance between MXene and graphene oxide allows for better product preparation. Furthermore, hydrochloric acid is preferred, as it has advantages over other acids such as sulfuric acid, including the simplest structure, small size, simple molecular composition, and easy removal of chloride ions.

[0025] Preferably, the pH of the system after the addition of the precipitant is 4.5 to 5.5, for example, it can be 4.5, 4.7, 4.8, 4.9, 5, 5.1, 5.2, 5.3, 5.4 or 5.5.

[0026] It is worth noting that when the pH is too high, there are too few hydrogen ions provided, making it difficult to form a thin film structure; when the pH is too low, the Ti3C2T in the system is affected. x MXene and graphene oxide directly aggregate to form a bulk three-dimensional structure, making it difficult to obtain thin film products.

[0027] Preferably, the concentration of the acid is 5 to 7 mol / L, for example, it can be 5 mol / L, 5.3 mol / L, 5.5 mol / L, 5.7 mol / L, 5.9 mol / L, 6.2 mol / L, 6.4 mol / L, 6.6 mol / L, 6.8 mol / L or 7 mol / L, etc.

[0028] Preferably, the second stirring speed is 400-800 rpm, for example, it can be 400 rpm, 445 rpm, 489 rpm, 534 rpm, 578 rpm, 623 rpm, 667 rpm, 712 rpm, 756 rpm or 800 rpm.

[0029] Preferably, the second stirring time is 25 to 40 minutes, for example, it can be 25 minutes, 27 minutes, 29 minutes, 30 minutes, 32 minutes, 34 minutes, 35 minutes, 37 minutes, 39 minutes or 40 minutes.

[0030] Preferably, the temperature of the second stirring is room temperature.

[0031] Preferably, the vacuum filtration is performed using an aqueous microporous membrane. Preferably, the aqueous microporous membrane is a CA cellulose acetate membrane.

[0032] Preferably, the drying includes vacuum drying.

[0033] Preferably, the drying temperature is 55-75°C, for example, it can be 55°C, 58°C, 60°C, 62°C, 64°C, 67°C, 69°C, 71°C, 73°C or 75°C.

[0034] Preferably, the drying time is 15 to 30 minutes, for example, it can be 15 minutes, 17 minutes, 19 minutes, 20 minutes, 22 minutes, 24 minutes, 25 minutes, 27 minutes, 29 minutes or 30 minutes.

[0035] The present invention does not impose any particular limitation on the drying pressure; any feasible pressure known to those skilled in the art can be used.

[0036] Preferably, the Ti3C2T x The preparation of MXene dispersions includes:

[0037] S11, mixed aluminum titanium carbide and fluorine source are dissolved in acid solution to carry out the first reaction to obtain the first reaction solution.

[0038] S12. The first reaction solution obtained in step S11 is centrifuged at least twice until the solution pH is neutral to obtain the first centrifuged solid phase.

[0039] S13, a mixed solvent and the first centrifuged solid phase from step S12 are subjected to ultrasonication and a second centrifugation to obtain a second centrifuged solid phase. The second centrifuged solid phase is then dried to obtain the Ti3C2T. x MXene;

[0040] S14, the Ti3C2T described in step S13 x MXene was dispersed in water to obtain the Ti3C2T. x MXene dispersion.

[0041] The aluminum titanium carbide mentioned in step S11 has the molecular formula Ti3AlC2 and the molecular weight 194.6.

[0042] Preferably, the fluorine source includes lithium fluoride.

[0043] Preferably, the acid solution includes hydrochloric acid.

[0044] Preferably, the concentration of the acid solution is 8.5 to 9.5 mol / L, for example, it can be 8.5 mol / L, 8.7 mol / L, 8.8 mol / L, 8.9 mol / L, 9 mol / L, 9.1 mol / L, 9.2 mol / L, 9.3 mol / L, 9.4 mol / L, or 9.5 mol / L.

[0045] Preferably, the mass ratio of the fluorine source to the aluminum titanium carbide is 0.8 to 1:1, for example, it can be 0.8:1, 0.83:1, 0.85:1, 0.87:1, 0.89:1, 0.92:1, 0.94:1, 0.96:1, 0.98:1 or 1:1, etc.

[0046] Preferably, the solid-liquid ratio of the aluminum titanium carbide to the acid solution is 0.5 to 1.5:20 g / mL, for example, it can be 0.5:20 g / mL, 0.7:20 g / mL, 0.8:20 g / mL, 0.9:20 g / mL, 1:20 g / mL, 1.1:20 g / mL, 1.2:20 g / mL, 1.3:20 g / mL, 1.4:20 g / mL, or 1.5:20 g / mL, etc.

[0047] Preferably, the temperature of the first reaction is 38 to 42°C, for example, it can be 38°C, 38.5°C, 38.9°C, 39.4°C, 39.8°C, 40.3°C, 40.7°C, 41.2°C, 41.6°C or 42°C.

[0048] Preferably, the reaction time is 20 to 30 hours, for example, 20 hours, 22 hours, 23 hours, 24 hours, 25 hours, 26 hours, 27 hours, 28 hours, 29 hours or 30 hours.

[0049] Preferably, the first reaction is carried out under stirring.

[0050] Preferably, the stirring speed of the first reaction is 400-600 rpm, for example, it can be 400 rpm, 423 rpm, 445 rpm, 467 rpm, 489 rpm, 512 rpm, 534 rpm, 556 rpm, 578 rpm or 600 rpm.

[0051] Preferably, the number of times the first centrifugation is at least twice in step S12 is 2 to 8 times, for example, it can be 2 times, 3 times, 4 times, 5 times, 6 times, 6 times, 7 times or 8 times, etc.

[0052] Preferably, the pH range of the neutral pH is 5 to 7, for example, it can be 5, 5.3, 5.5, 5.7, 5.9, 6.2, 6.4, 6.6, 6.8 or 7, etc.

[0053] Preferably, the solvent in step S13 includes water. The present invention does not have a particular limitation on the liquid-to-solid ratio of the solvent to the centrifuged solid phase, as long as it can effectively achieve ultrasound. Preferably, the power of the ultrasound is 200–400 W, for example, it can be 200 W, 223 W, 245 W, 267 W, 289 W, 312 W, 334 W, 356 W, 378 W, or 400 W, etc.

[0054] Preferably, the ultrasound duration is 0.5 to 1.5 hours, for example, it can be 0.5 hours, 0.7 hours, 0.8 hours, 0.9 hours, 1 hour, 1.1 hours, 1.2 hours, 1.3 hours, 1.4 hours or 1.5 hours.

[0055] Preferably, the second centrifugation includes a first-stage centrifugation and a second-stage centrifugation.

[0056] The present invention preferably uses MXene material with a better sheet-like structure through multi-stage centrifugation.

[0057] Preferably, the rotation speed of the first stage centrifuge is 800-1200 r / min, for example, it can be 800 r / min, 845 r / min, 889 r / min, 934 r / min, 978 r / min, 1023 r / min, 1067 r / min, 1112 r / min, 1156 r / min or 1200 r / min, etc.

[0058] Preferably, the first-stage centrifugation time is 15 to 30 minutes, for example, it can be 15 minutes, 17 minutes, 19 minutes, 20 minutes, 22 minutes, 24 minutes, 25 minutes, 27 minutes, 29 minutes or 30 minutes.

[0059] Preferably, the rotation speed of the second-stage centrifuge is 5000-7000 r / min, for example, it can be 5000 r / min, 5200 r / min, 5400 r / min, 5600 r / min, 5800 r / min, 6100 r / min, 6300 r / min, 6500 r / min, 6700 r / min or 7000 r / min, etc.

[0060] Preferably, the second-stage centrifugation time is 30 to 50 minutes, for example, 30 minutes, 33 minutes, 35 minutes, 37 minutes, 39 minutes, 42 minutes, 44 minutes, 46 minutes, 48 ​​minutes, or 50 minutes.

[0061] Preferably, the drying in step S13 includes freeze drying.

[0062] Preferably, the freeze-drying temperature is -30 to -40°C, for example, it can be -30°C, -31°C, -32°C, -33°C, -34°C, -35°C, -36°C, -37°C, -38°C, -39°C, or -40°C.

[0063] Preferably, the freeze-drying time is 20 to 25 hours, for example, 20 hours, 20.6 hours, 21.2 hours, 21.7 hours, 22.3 hours, 22.8 hours, 23.4 hours, 23.9 hours, 24.5 hours, or 25 hours.

[0064] Preferably, the absolute pressure of the freeze-drying is 100Pa to 200Pa, for example, it can be 100Pa, 112Pa, 123Pa, 134Pa, 145Pa, 156Pa, 167Pa, 178Pa, 189Pa or 200Pa.

[0065] Preferably, the preparation of the graphene oxide dispersion includes:

[0066] S21. Phosphorus pentoxide and potassium persulfate are added sequentially to concentrated sulfuric acid. After the solution becomes clear, it is heated and cooled sequentially to obtain the first mixture.

[0067] S22. Graphite is added to the first mixture to carry out the second reaction. The resulting second reaction material is cooled, precipitated by water precipitation and dried in sequence to obtain pre-oxidized graphite.

[0068] S23. Add the pre-oxidized graphite and potassium permanganate described in step S22 to concentrated sulfuric acid in sequence, and obtain the third reaction solution after the third reaction.

[0069] S24. The third reaction liquid described in step S23 is diluted and mixed with an oxidant, and then subjected to a fourth oxidation reaction. The resulting fourth oxidation reaction material is then cooled, separated from solids and liquids, washed, dialyzed and dried to obtain the graphene oxide.

[0070] S25. The graphene oxide obtained in step S24 is dispersed in water to obtain the graphene oxide dispersion.

[0071] Preferably, the concentration of concentrated sulfuric acid in step S21 is 18.4 mol / L.

[0072] Preferably, the solid-liquid ratio of phosphorus pentoxide and concentrated sulfuric acid is 0.5 to 1.5:3 g / mL, for example, it can be 0.5:3 g / mL, 0.7:3 g / mL, 0.8:3 g / mL, 0.9:3 g / mL, 1:3 g / mL, 1.1:3 g / mL, 1.2:3 g / mL, 1.3:3 g / mL, 1.4:3 g / mL, or 1.5:3 g / mL, etc.

[0073] Preferably, the mass ratio of phosphorus pentoxide to potassium persulfate is 0.8 to 1.2:1, for example, it can be 0.8:1, 0.85:1, 0.89:1, 0.94:1, 0.98:1, 1.03:1, 1.07:1, 1.12:1, 1.16:1 or 1.2:1, etc.

[0074] Preferably, the heating temperature is 75-85°C, for example, it can be 75°C, 77°C, 78°C, 79°C, 80°C, 81°C, 82°C, 83°C, 84°C or 85°C.

[0075] Preferably, the heating time is 2 to 4 hours, for example, it can be 2 hours, 2.3 hours, 2.5 hours, 2.7 hours, 2.9 hours, 3.2 hours, 3.4 hours, 3.6 hours, 3.8 hours or 4 hours.

[0076] Preferably, smoke is continuously emitted during the heating process.

[0077] Preferably, the solid-liquid ratio of graphite to the first mixture in step S22 is 1:1.2 to 1.3 g / mL, for example, it can be 1:1.2 mg / L, 1:1.21 mg / L, 1:1.22 mg / L, 1:1.23 mg / L, 1:1.24 mg / L, 1:1.25 mg / L, 1:1.28 mg / L or 1:1.3 mg / L, etc.

[0078] Preferably, the temperature of the second reaction is 75-85°C, for example, it can be 75°C, 77°C, 78°C, 79°C, 80°C, 81°C, 82°C, 83°C, 84°C or 85°C.

[0079] Preferably, the second reaction time is 2 to 4 hours, for example, it can be 2 hours, 2.3 hours, 2.5 hours, 2.7 hours, 2.9 hours, 3.2 hours, 3.4 hours, 3.6 hours, 3.8 hours or 4 hours.

[0080] Preferably, the cooling time of the second reactant is 4 to 8 hours, for example, it can be 4 hours, 4.5 hours, 4.9 hours, 5.4 hours, 5.8 hours, 6.3 hours, 6.7 hours, 7.2 hours, 7.6 hours or 8 hours.

[0081] Preferably, the water precipitation includes: mixing water and the second reactant and stirring, followed by solid-liquid separation.

[0082] Preferably, the solid-liquid separation includes vacuum filtration.

[0083] The present invention does not have a special limitation on the liquid-solid ratio of the water and the second reactant, as long as it can be washed to neutral.

[0084] Preferably, the solid phase obtained from the solid-liquid separation is then washed with water until the pH of the filtrate is 6.8 to 7.2, for example, 6.8, 6.9, 7, 7.1 or 7.2.

[0085] Preferably, the drying time in step S22 is 8 to 12 hours, for example, 8 hours, 8.5 hours, 8.9 hours, 9.4 hours, 9.8 hours, 10.3 hours, 10.7 hours, 11.2 hours, 11.6 hours or 12 hours.

[0086] Preferably, the drying temperature in step S22 is 60–80°C, for example, 60°C, 63°C, 65°C, 67°C, 69°C, 72°C, 74°C, 76°C, 78°C, or 80°C. Preferably, the concentration of concentrated sulfuric acid in step S23 is 18.4 mol / L.

[0087] Preferably, the solid-liquid ratio of the pre-oxidized graphite to concentrated sulfuric acid is 1:20 to 25 g / mL, for example, it can be 1:20 g / mL, 1:20.5 g / mL, 1:21 g / mL, 1:21.5 g / mL, 1:22 g / mL, 1:23 g / mL, 1:24 g / mL or 1:25 g / mL, etc.

[0088] Preferably, the mass ratio of potassium permanganate to pre-oxidized graphite is 0.5 to 1.5:3, for example, it can be 0.5:3, 0.7:3, 0.8:3, 0.9:3, 1:3, 1.1:3, 1.2:3, 1.3:3, 1.4:3 or 1.5:3, etc.

[0089] Preferably, the operation temperature for sequentially adding the pre-oxidized graphite and potassium permanganate described in step S22 to concentrated sulfuric acid in step S23 is below 20°C.

[0090] Preferably, the temperature of the third reaction is 30 to 45°C, for example, it can be 30°C, 32°C, 34°C, 35°C, 37°C, 39°C, 40°C, 42°C, 44°C or 45°C.

[0091] Preferably, the time for the third reaction is 1 to 3 hours, for example, it can be 1 hour, 1.3 hours, 1.5 hours, 1.7 hours, 1.9 hours, 2.2 hours, 2.4 hours, 2.6 hours, 2.8 hours or 3 hours.

[0092] Preferably, dilution is performed after the third reaction.

[0093] Preferably, the dilution is performed using water, and the volume ratio of water to the material after the third reaction is 1.8 to 2.5:1, for example, it can be 1.8:1, 1.9:1, 2:1, 2.1:1, 2.2:1, 2.3:1, 2.4:1 or 2.5:1, etc.

[0094] Preferably, the oxidant in step S24 is a hydrogen peroxide solution.

[0095] Preferably, the concentration of the hydrogen peroxide solution is 15-40 wt%, for example, it can be 15 wt%, 18 wt%, 21 wt%, 24 wt%, 27 wt%, 29 wt%, 32 wt%, 35 wt%, 38 wt%, or 40 wt%.

[0096] Preferably, the washing solution used in step S24 is hydrochloric acid.

[0097] Preferably, the dialysis time is 6 to 10 days, for example, 6 days, 7 days, 8 days, 9 days or 10 days.

[0098] Preferably, the drying in step S24 is freeze drying.

[0099] As a preferred embodiment of the first aspect of the present invention, the preparation method includes:

[0100] Secondly, this invention provides a Ti3C2T x MXene-graphene oxide material, Ti3C2T x MXene-graphene oxide material uses the Ti3C2T described in the first aspect. x The MXene-graphene oxide material was prepared by a specific method.

[0101] The Ti3C2T prepared by the first aspect of the present invention x MXene (graphene oxide) materials have excellent properties, including superior bending resistance and good electrical conductivity, making them suitable for use in wearable sensors and supercapacitors, with broad application prospects.

[0102] Preferably, the Ti3C2T x MXene-graphene oxide material is a thin film material with a thickness of 1 to 10 μm, for example, it can be 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm or 10 μm, etc.

[0103] From a microscopic perspective, MXene's two-dimensional layered structure is composed of Ti metal ions and carbon layers, while graphene oxide's two-dimensional planar structure is composed of carbon layers, exhibiting good elasticity and flexibility. These different structural characteristics allow them to complement each other during the composite process, forming a composite material with excellent mechanical properties. Furthermore, an energy dispersion mechanism exists between MXene and graphene oxide during the composite process. The interaction between the two-dimensional layered structure of MXene and the two-dimensional planar structure of graphene oxide leads to uniform pressure dispersion and distribution, thereby increasing the pressure sensing performance of the composite material. In addition, the abundant functional groups on the surfaces of graphene oxide and MXene facilitate covalent chemical cross-linking of the composite film, significantly improving mechanical strength and toughness, hydrophobicity, water resistance or solvent resistance, and oxidative stability. This is primarily because the similar functional groups in graphene oxide and MXene sheets induce a strong hydrogen-Ti-OC bonding interaction mechanism. The addition of MXene nanosheets improves the alignment and ion transport of the graphene sheets while minimizing self-stacking. Large-size graphene oxide sheets effectively prevent oxygen permeation, and because graphene oxide reacts preferentially with oxygen in the air, it alleviates the problem of easy oxidation of MXene. By easily adjusting the MXene-graphene oxide mass ratio and the film thickness, the resistance value can be controlled over a wide range, thus enabling the fabrication of pressure sensors with different pressure ranges and sensitivities.

[0104] Thirdly, the present invention provides a Ti3C2T as described in the second aspect. x Applications of MXene (graphene oxide) materials in wearable pressure sensors or supercapacitors.

[0105] Fourthly, the present invention provides a detection device, the detection device comprising the Ti3C2T described in the second aspect. x MXene-graphene oxide material.

[0106] The Ti3C2T provided by this invention x MXene (graphene oxide) material, as a wearable sensor that can withstand a certain degree of stretching and bending, has good adhesion to human skin, showing good substrate applicability and stability, and can be used in motion detection or health monitoring.

[0107] Preferably, the detection device includes a motion detection device or a health monitoring device.

[0108] Preferably, the motion detection device includes any one or a combination of at least two of the following: a facial micro-expression detection device, a lip muscle detection device, an eye muscle detection device, or a chewing pressure detection device.

[0109] Preferably, the health monitoring device includes a heart rate detection device.

[0110] Compared with the prior art, the present invention has at least the following beneficial effects:

[0111] (1) The Ti3C2T provided by this invention x The preparation method of MXene-graphene oxide material is based on MXene and graphene oxide. The resulting thin film product has low resistance, which is less than 55Ω / cm. It has good conductivity and the synthesis process is simple, efficient, and low-cost, which has good economic advantages.

[0112] (2) The Ti3C2T provided by this invention x The product prepared by the MXene-graphene oxide material preparation method can be used as a wearable sensor that can withstand a certain degree of stretching and bending. It has good adhesion to human skin and shows good substrate applicability and stability.

[0113] (3) The pressure sensor provided by the present invention exhibits low detection limit, good stability and repeatability, and can realize real-time portable monitoring of human joint activity and human pulse, which is suitable for early assessment of human health status. Moreover, it adopts a simple vacuum filtration and packaging preparation technology, combining traditional electrochemical detection system and big data Internet of Things technology, which can be widely used in remote real-time monitoring and recording of self-supporting wearable smart pressure sensors. Attached Figure Description

[0114] Figure 1 This is a schematic diagram illustrating the fabrication of the MXene-based pressure sensor of this invention.

[0115] Figures 2-3 This is a SEM image of the MXene-graphene oxide composite layered structure obtained in Example 1 of the present invention.

[0116] Figure 4 This is the Raman spectrum of the MXene-graphene oxide composite layered structure prepared in Example 1 of the present invention.

[0117] Figure 5 The image shows the XRD pattern of the MXene-graphene oxide composite layered structure obtained in Example 1 of this invention.

[0118] Figure 6 This is a graph showing the current-time change detected by the sensor when the sensor is subjected to 100 cycles of finger pressure in Application Example 1 of the present invention.

[0119] Figure 7 This is a current-time change graph detected by the sensor when the muscles around the eye change during blinking in Application Example 2 of the present invention.

[0120] Figure 8 This is a current-time change graph detected by the sensor when the side changes during blinking, as shown in Application Example 2 of the present invention.

[0121] Figure 9 This is a graph showing the current-time change detected by the sensor during chewing in Application Example 3 of the present invention.

[0122] Figure 10 This is a current-time change graph detected by a sensor when the neck pulse beats in Application Example 4 of the present invention.

[0123] Figure 11 This is a current-time change graph detected by a sensor when the wrist pulse beats in Application Example 4 of the present invention. Detailed Implementation

[0124] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0125] The present invention will now be described in further detail. However, the examples described below are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention is determined by the claims.

[0126] It should be noted that the terminology used herein is for the purpose of describing particular implementations only and is not intended to limit the scope of exemplary embodiments of the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms “comprising” and / or “including” are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0127] It is worth noting that the Ti3C2T obtained by this invention x When MXene-graphene oxide is used as a sensor or supercapacitor, it is a self-supporting material. The self-supporting material means that when it is used, it is in the form of a thin film and does not need to be coated or attached to a substrate. It has the properties of bending resistance and conductivity.

[0128] Example 1

[0129] This embodiment provides a Ti3C2T x A method for preparing MXene-graphene oxide materials, the method comprising:

[0130] S1, Ti3C2T x Preparation of MXene dispersion;

[0131] The Ti3C2T x The preparation of MXene dispersions includes:

[0132] S11. Take 15 ml of concentrated HCl (concentration of 37 wt%), dilute it with 5 ml of deionized water and place it in a plastic reaction tube. Then weigh 1 g of lithium fluoride and 1 g of aluminum titanium carbide and add them to the above reaction tube. After the two are completely dissolved, stir at 600 r / min at 35℃ for the first reaction. The first reaction time is 24 h to obtain the first reaction solution.

[0133] S12. The first reaction solution obtained in step S11 is centrifuged four times until the solution pH is neutral (6.8-7.2) to obtain the first centrifuged solid phase;

[0134] S13, mix water and the first centrifuged solid phase from step S12, and sonicate at 300W for 1 hour. Then, centrifuge the resulting dispersion at 1000 rpm for 20 minutes, followed by centrifugation of the supernatant at 6000 rpm for 40 minutes to obtain the second centrifuged solid phase. The second centrifuged solid phase is dried at -35℃ and 150Pa for 20 hours to obtain the Ti3C2T. x MXene;

[0135] S14, the Ti3C2T described in step S13 xMXene was dispersed in water to obtain 1 g / L of the aforementioned Ti3C2T. x MXene dispersion.

[0136] S2, Preparation of graphene oxide dispersion;

[0137] The preparation of the graphene oxide dispersion includes:

[0138] S21. Under vigorous stirring (800 r / min), 2.5 g of phosphorus pentoxide (P2O5) and 2.5 g of potassium persulfate (K2S2O8) were added sequentially to 7.5 ml of concentrated sulfuric acid solution (concentration of 18.4 mol / L). After obtaining a clear solution, the solution was heated to 80 °C in an oil bath, during which fumes were continuously generated. The solution was then cooled to obtain the first mixture.

[0139] S22. Weigh 5g of natural graphite and carefully add it to 6mL of the first mixture. Carry out the second reaction at 75℃ for 3h to obtain a dark green mixture (i.e., the second reaction material). Cool the second reaction material at room temperature for 6h. Slowly add deionized water to the second reaction material and stir to precipitate the water. Then filter the black mixture while stirring continuously and wash it with deionized water until the pH of the filtrate is 7. Then dry the precipitate in a drying oven at 65℃ for 12h at room temperature to obtain pre-oxidized graphite.

[0140] S23. Weigh 1g of the obtained pre-oxidized graphite and carefully add it to a 500ml beaker containing 23ml of concentrated sulfuric acid (concentration of 18.4mol / L). Under the condition of ice-water bath, add 3g of potassium permanganate powder while stirring (the whole process is controlled within 20℃). Remove the ice-water bath and transfer the above mixture to a 250ml round-bottom flask. Stir in an oil bath at 35℃ for 2h to carry out the third reaction. During the third reaction, bubbles are generated, the mixture becomes more concentrated, the bubbles shrink, and the system changes from dark green to gray-green to obtain the third reaction solution.

[0141] S24. The third reaction solution described in step S23 was diluted with 46 ml of water to obtain a yellowish-brown turbid solution. The turbid solution was further diluted until it turned brown. After 15 minutes, 140 ml of deionized water was added, followed by the slow addition of 2.5 ml of 30% hydrogen peroxide solution to carry out the fourth oxidation reaction. During the fourth oxidation reaction, a large number of bubbles were generated. After the reaction was completed, the turbid solution turned bright yellow. After cooling, it was filtered and washed multiple times with 250 ml of 1:10 diluted hydrochloric acid to obtain a yellow cake-like substance. This substance was then sonicated and centrifuged, dialyzed at 22°C for one week, and freeze-dried to obtain the graphene oxide.

[0142] S25. The graphene oxide obtained in step S24 is dispersed in water to obtain a 1 g / L graphene oxide dispersion.

[0143] S3, Ti3C2T x Preparation of MXene-graphene oxide materials: using Ti3C2T x A mixture of MXene and graphene oxide in a mass ratio of 4:1 (Ti3C2T) x The first mixture, consisting of MXene dispersion (20 mL) and graphene oxide dispersion, was subjected to a series of reactions under nitrogen atmosphere. These reactions included stirring at 500 rpm for 30 min, adding 6 mol / L hydrochloric acid to adjust the pH to 5.0 for coagulation, followed by stirring at 550 rpm for 30 min at room temperature. The resulting second mixture was then vacuum-filtered through a water-based microporous membrane (CA cellulose acetate membrane, 0.45 μm pore size, 0.1 mm thickness, 50 mm diameter) and dried at 55 °C for 20 min to obtain the Ti3C2T. x MXene-graphene oxide material.

[0144] In this embodiment, Ti3C2T x The principle of combining MXene and graphene oxide is as follows: Figure 1 As shown, the prepared Ti3C2T x SEM images of MXene-graphene oxide materials are shown below. Figures 2-3 As shown, from Figures 2-3 It can be seen that the Ti3C2T prepared by this invention x MXene-graphene oxide material is a layered material in which Ti3C2T is formed. x A thin film with alternating layers of MXene and graphene oxide is used, but it is not required that each alternation be a single layer; for example, it can be two layers of Ti3C2T. x MXene, followed by three layers of graphene oxide, etc. Since the diffraction peaks of graphene oxide and MXene overlap, and the amount of graphene oxide is lower than that of MXene, to prove the presence of graphene oxide, the prepared Ti3C2T... x Raman spectra of MXene-graphene oxide materials are as follows: Figure 4 As shown, from Figure 4 It can be seen that the D and G bands of graphene oxide are associated with the graphitic structure and the graphene edge (or graphene sheet containing defects), respectively, thus proving the presence of graphene oxide in the composite structure. Meanwhile, we also found three Raman scattering peaks corresponding to MXene on the left side, further confirming the presence of MXene. The prepared Ti3C2T x The XRD pattern of MXene-graphene oxide material is as follows: Figure 5 As shown, from Figure 5It can be seen that there is a diffraction peak of the MXene (002) crystal plane at approximately 7.5°, a diffraction peak of the MXene (110 / 200) crystal plane at 20°, and a diffraction peak of the (104) crystal plane at 40°. This proves the existence of MXene.

[0145] The thin film resistivity obtained in this embodiment is approximately 50 Ω / cm, exhibiting excellent conductivity and broad application prospects.

[0146] Example 2

[0147] This embodiment provides a Ti3C2T x A method for preparing MXene-graphene oxide materials, the method comprising:

[0148] S1, Ti3C2T x Preparation of MXene dispersion;

[0149] The Ti3C2T x The preparation of MXene dispersions includes:

[0150] S11. Take 16 ml of concentrated HCl (concentration of 36 wt%), dilute it with 3 ml of deionized water and place it in a plastic reaction tube. Then weigh 1.2 g of lithium fluoride and 1 g of aluminum titanium carbide and add them to the above reaction tube. After the two are completely dissolved, stir at 400 r / min at 35 °C for the first reaction. The first reaction time is 20 h to obtain the first reaction solution.

[0151] S12. The first reaction solution obtained in step S11 is centrifuged four times until the solution pH is neutral (7.0) to obtain the first centrifuged solid phase.

[0152] S13, mix water and the first centrifuged solid phase from step S12, and sonicate at 400W for 1 hour. Then, centrifuge the resulting dispersion at 800 rpm for 30 minutes, followed by centrifugation of the supernatant at 5000 rpm for 50 minutes to obtain the second centrifuged solid phase. The second centrifuged solid phase is dried at -40℃ and 200Pa for 25 hours to obtain the Ti3C2T. x MXene;

[0153] S14, the Ti3C2T described in step S13 x MXene was dispersed in water to obtain 0.5 g / L of the described Ti3C2T. x MXene dispersion.

[0154] S2, Preparation of graphene oxide dispersion;

[0155] The preparation of the graphene oxide dispersion includes:

[0156] S21. Under vigorous stirring (900 r / min), 2.3 g of phosphorus pentoxide (P2O5) and 3.0 g of potassium persulfate (K2S2O8) were added sequentially to 6 ml of concentrated sulfuric acid solution (concentration of 18.4 mol / L). After obtaining a clear solution, the solution was heated to 75°C in an oil bath, during which fumes were continuously generated. The solution was then cooled to obtain the first mixture.

[0157] S22. Weigh 5g of natural graphite and carefully add it to 6.2mL of the first mixture. Carry out the second reaction at 80℃ for 1h to obtain a dark green mixture (i.e., the second reaction material). Cool the second reaction material at room temperature for 4h. Slowly add deionized water to the second reaction material and stir to precipitate the water. Then filter the black mixture while stirring continuously and wash it with deionized water until the pH of the filtrate is 7. Then dry the precipitate in a drying oven at 75℃ for 10h at room temperature to obtain pre-oxidized graphite.

[0158] S23. Weigh 1.2g of the obtained pre-oxidized graphite and carefully add it to a 500ml beaker containing 23ml of concentrated sulfuric acid (concentration of 18.4mol / L). Under the condition of ice water bath, add 2.8g of potassium permanganate powder while stirring (the whole process is controlled within 20℃). Remove the ice water bath and transfer the above mixture to a 250ml round bottom flask. Stir in an oil bath at 35℃ for 1.5h to carry out the third reaction. During the third reaction, bubbles are generated, the mixture becomes thicker, the bubbles shrink, and the system changes from dark green to gray-green to obtain the third reaction solution.

[0159] S24. The third reaction solution described in step S23 was diluted with 45 ml of water to obtain a yellowish-brown turbid solution. The turbid solution was further diluted until it turned brown. After 15 minutes, 140 ml of deionized water was added, followed by the slow addition of 2.0 ml of 28% hydrogen peroxide solution to carry out the fourth oxidation reaction. During the fourth oxidation reaction, a large number of bubbles were generated. After the reaction was completed, the turbid solution turned bright yellow. After cooling, it was filtered and washed multiple times with 250 ml of 1:10 diluted hydrochloric acid to obtain a yellow cake-like substance. This substance was then sonicated and centrifuged, dialyzed at 24°C for one week, and freeze-dried to obtain the graphene oxide.

[0160] S25. The graphene oxide obtained in step S24 is dispersed in water to obtain a 0.5 g / L graphene oxide dispersion.

[0161] S3, Ti3C2T x Preparation of MXene-graphene oxide materials: using Ti3C2T x A mixture of MXene and graphene oxide in a mass ratio of 2:1 (Ti3C2T) xThe first mixture, consisting of MXene dispersion (20 mL) and graphene oxide dispersion, was subjected to a series of reactions under nitrogen atmosphere. These reactions included stirring at 600 rpm for 25 min, adding 5.5 mol / L hydrochloric acid to adjust the pH to 5.5 for coagulation, followed by stirring at 600 rpm for 25 min at room temperature. The resulting second mixture was then vacuum-filtered through a water-based microporous membrane (CA cellulose acetate membrane, 0.45 μm pore size, 0.1 mm thickness, 50 mm diameter) and dried at 60 °C for 30 min to obtain the Ti3C2T. x MXene-graphene oxide material.

[0162] The thin film resistivity obtained in this embodiment is approximately 45 Ω / cm, exhibiting excellent conductivity and broad application prospects.

[0163] Example 3

[0164] This embodiment provides a Ti3C2T x A method for preparing MXene-graphene oxide materials, the method comprising:

[0165] S1, Ti3C2T x Preparation of MXene dispersion;

[0166] The Ti3C2T x The preparation of MXene dispersions includes:

[0167] S11. Take 14 ml of concentrated HCl (concentration of 38 wt%), dilute it with 6 ml of deionized water and place it in a plastic reaction tube. Then weigh 1.2 g of lithium fluoride and 1 g of aluminum titanium carbide and add them to the above reaction tube. After the two are completely dissolved, stir at 800 r / min at 40℃ for the first reaction. The first reaction time is 25 h to obtain the first reaction solution.

[0168] S12. The first reaction solution obtained in step S11 is centrifuged four times until the solution pH is neutral (6.8-7.0) to obtain the first centrifuged solid phase.

[0169] S13, mix water and the first centrifuged solid phase from step S12, and sonicate at 250W for 1.5 h. Then, centrifuge the resulting dispersion at 1200 rpm for 18 min, followed by centrifugation of the supernatant at 7000 rpm for 30 min to obtain the second centrifuged solid phase. The second centrifuged solid phase is dried at -40℃ and 100 Pa for 28 h to obtain the Ti3C2T. x MXene;

[0170] S14, the Ti3C2T described in step S13 xMXene was dispersed in water to obtain 1.5 g / L of the described Ti3C2T. x MXene dispersion.

[0171] S2, Preparation of graphene oxide dispersion;

[0172] The preparation of the graphene oxide dispersion includes:

[0173] S21. Under vigorous stirring (750 r / min), 2.5 g of phosphorus pentoxide (P2O5) and 2.8 g of potassium persulfate (K2S2O8) were added sequentially to 9.0 ml of concentrated sulfuric acid solution (concentration of 18.4 mol / L). After obtaining a clear solution, the solution was heated to 85 °C in an oil bath, during which fumes were continuously generated. The solution was then cooled to obtain the first mixture.

[0174] S22. Weigh 5g of natural graphite and carefully add it to 6mL of the first mixture. Carry out the second reaction at room temperature for 4h-86h. Slowly add deionized water to the second reaction material and stir to allow water precipitation. Then filter the black mixture while stirring continuously and wash it with deionized water until the pH of the filtrate is 7. Then dry the precipitate in a drying oven at room temperature at 66℃ for 18h to obtain pre-oxidized graphite.

[0175] S23. Weigh 1.5g of the obtained pre-oxidized graphite and carefully add it to a 500ml beaker containing 24ml of concentrated sulfuric acid (concentration of 18.4mol / L). Under the condition of ice water bath, add 2.5g of potassium permanganate powder while stirring (the whole process is controlled within 20℃). Remove the ice water bath and transfer the above mixture to a 250ml round bottom flask. Stir in an oil bath at 40℃ for 2.5h to carry out the third reaction. During the third reaction, bubbles are generated, the mixture becomes more concentrated, the bubbles shrink, and the system changes from dark green to gray-green to obtain the third reaction solution.

[0176] S24. The third reaction solution described in step S23 was diluted with 46 ml of water to obtain a yellowish-brown turbid solution. The turbid solution was further diluted until it turned brown. After 15 minutes, 140 ml of deionized water was added, followed by the slow addition of 2.5 ml of 35% hydrogen peroxide solution to carry out the fourth oxidation reaction. During the fourth oxidation reaction, a large number of bubbles were generated. After the reaction was completed, the turbid solution turned bright yellow. After cooling, it was filtered and washed multiple times with 250 ml of 1:10 diluted hydrochloric acid to obtain a yellow cake-like substance. This substance was then sonicated and centrifuged, dialyzed at 22°C for one week, and freeze-dried to obtain the graphene oxide.

[0177] S25. The graphene oxide obtained in step S24 is dispersed in water to obtain a 1.5 g / L graphene oxide dispersion.

[0178] S3, Ti3C2T x Preparation of MXene-graphene oxide materials: using Ti3C2T x A mixture of MXene and graphene oxide in a mass ratio of 5:1 (Ti3C2T) x The first mixture, consisting of MXene dispersion (20 mL) and graphene oxide dispersion, was subjected to a series of reactions under nitrogen atmosphere: stirring at 600 rpm for 40 min, adding 6.5 mol / L hydrochloric acid to adjust the pH to 5.5 for coagulation, and then stirring again at 600 rpm for 40 min at room temperature. The resulting second mixture was then vacuum filtered through an aqueous microporous membrane (CA cellulose acetate membrane, 0.45 μm pore size, 0.1 mm thickness, 50 mm diameter) and dried at 60 °C for 30 min to obtain the Ti3C2T. x MXene-graphene oxide material.

[0179] The thin film resistivity obtained in this embodiment is approximately 55 Ω / cm, exhibiting excellent conductivity and broad application prospects.

[0180] Example 4

[0181] This embodiment provides a Ti3C2T x A method for preparing MXene-graphene oxide materials, wherein the preparation method excludes Ti3C2T x Ti3C2T in MXene dispersion and graphene oxide dispersion x Except for the mass ratio of MXene to graphene oxide being 1.33:1, everything else is the same as in Example 1, and will not be repeated here.

[0182] In Example 4, Ti3C2T x The film resistance of the film with a mass ratio of MXene to graphene oxide of 1.33:1 reached 500 Ω / cm. The main factor for this change is that graphene oxide itself is non-conductive. As the amount of graphene oxide increases, the layered structure may be compressed, which may prevent the formation of a conductive network between the layers, resulting in a sudden increase in resistance and a significant reduction in the sensitivity of the sensor.

[0183] Example 5

[0184] This embodiment provides a Ti3C2T x A method for preparing MXene-graphene oxide materials, wherein the preparation method excludes Ti3C2T x Ti3C2T in MXene dispersion and graphene oxide dispersion x Except for the mass ratio of MXene to graphene oxide being 2:1, everything else is the same as in Example 1, and will not be repeated here.

[0185] In this embodiment, the thin film resistance is approximately 70 Ω / cm. The main factor contributing to this variation is that graphene oxide itself is non-conductive. As the amount of graphene oxide increases, the layered structure may be compressed, potentially preventing the formation of a conductive network between layers. This results in a sudden increase in resistance and significantly reduces the sensor's sensitivity.

[0186] Example 6

[0187] This embodiment provides a Ti3C2T x The preparation method of MXene-graphene oxide material is the same as in Example 1, except that the precipitant is sulfuric acid, and will not be repeated here. Example 7

[0188] This embodiment provides a Ti3C2T x The preparation method of MXene-graphene oxide material is the same as that in Example 1, except that the precipitant is nitric acid, and will not be repeated here.

[0189] In Examples 6 and 7, sulfuric acid and nitric acid were used as precipitants. The effect of removing molecular acids was not as good as that of hydrochloric acid used in Example 1, resulting in a decrease in the quality of the final film compared to Example 1.

[0190] Example 8

[0191] This embodiment provides a Ti3C2T x A method for preparing MXene-graphene oxide materials, wherein the preparation method excludes Ti3C2T x Ti3C2T in MXene dispersion x Except for the concentration of MXene being 2.0 g / L, everything else is the same as in Example 1, and will not be repeated here.

[0192] In this embodiment, due to Ti3C2T x The high concentration of MXene makes it difficult to form a thin film structure after vacuum filtration, resulting in a more island-like three-dimensional structure, which is unsuitable for subsequent wearable products.

[0193] Example 9

[0194] This embodiment provides a Ti3C2T x A method for preparing MXene-graphene oxide materials, wherein the preparation method excludes Ti3C2T x Ti3C2T in MXene dispersion x Except for the concentration of MXene being 0.1 g / L, everything else is the same as in Example 1, and will not be repeated here.

[0195] This embodiment is due to Ti3C2Tx The low concentration of MXene makes it difficult to form thin film products after vacuum filtration, and the products cannot be formed.

[0196] Example 10

[0197] This embodiment provides a Ti3C2T x The preparation method of MXene-graphene oxide material is the same as that in Example 1, except that the pH of the system is 4.0 after the addition of the precipitant. It will not be described again here.

[0198] In this embodiment, the pH is too low, which will cause the sedimentation effect to be too intense, forming three-dimensional islands and making it impossible to form a uniform two-dimensional film, resulting in a decrease in the reproducibility of the pressure sensor.

[0199] Example 11

[0200] This embodiment provides a Ti3C2T x The preparation method of MXene-graphene oxide material is the same as that in Example 1, except that the pH of the system is 6.0 after the addition of the precipitant. It will not be repeated here.

[0201] In this embodiment, pH=6.0 will result in insufficient flocculation effect and excessive filtration time. MXene and graphene cannot be completely flocculated to form a two-dimensional uniform film, leading to uneven sensor resistance and decreased pressure sensing performance.

[0202] Comparative Example 1

[0203] This comparative example provides a Ti3C2T x The preparation method of MXene-graphene oxide material is the same as that in Example 1, except that hydrochloric acid is not added as a precipitant in step S3, and will not be described again here.

[0204] In this comparative example, the absence of hydrochloric acid as a precipitant prevents MXene and graphene oxide from completely agglomerating to form a uniform two-dimensional film, resulting in uneven sensor resistance and decreased pressure sensing performance.

[0205] Comparative Example 2

[0206] This comparative example provides a Ti3C2T x The preparation method of MXene-graphene oxide material is the same as that in Example 1, except that the second stirring is not performed in step S3, and will not be repeated here.

[0207] In this comparative example, the lack of a second stirring resulted in poor uniformity of the film formed by the aggregation of MXene and graphene oxide, leading to poor sensitivity after application.

[0208] Comparative Example 3

[0209] This comparative example provides a Ti3C2T x The preparation method of MXene-graphene oxide material is the same as that in Example 1, except that the first stirring is not performed in step S3, and will not be repeated here.

[0210] In this comparative example, because the first stirring was not performed, the dispersion of MXene and graphene oxide was uneven in the early stage. After adding the precipitant and performing the second stirring, a large portion of each precipitated directly, making it difficult to form an alternating layered film product.

[0211] Application Example 1

[0212] This application example provides a finger pressure sensor, which uses the Ti3C2T material prepared in Example 1. x MXene-graphene oxide material. In the Ti3C2T... x The MXene-graphene oxide material has adhesive tape on both sides to form a wearable finger pressure sensor.

[0213] Since the pressure applied by a finger is among the greatest in daily life activities and health monitoring, relying on the sensor's excellent stability, pressure was applied to the sensor 100 times sequentially, and the time-current change was as follows: Figure 6 As shown, its current response is relatively stable. Even if fluctuations occur, it is due to uneven pressure applied by the finger. The pressure sensor has the function of rapid response and instant recovery to the loading / unloading of the sensor. The response time of the pressure sensor is calculated to be about 0.45s, which is relatively fast compared to other sensors.

[0214] Due to the high conductivity of MXene and graphene, pressure sensors can carry relatively large currents at very low voltages, demonstrating extremely low power consumption without compromising sensitivity. The layered sensor in this work applied a DC voltage of only 0.05V, significantly lower than the voltages (2-5V) of field-effect transistor sensors. This low operating voltage also means that the immense potential of pressure sensors can be integrated into self-powered and lightweight wearable devices using small, portable energy harvesting and storage devices.

[0215] Application Example 2

[0216] This application example provides a real-time facial micro-expression monitoring device, which uses the Ti3C2T provided in Example 2. x The specific preparation of MXene-graphene oxide material includes: preparing Ti3C2T xThe MXene-graphene oxide film was cut and connected to copper wires, then sealed with polyimide tape. Medical double-sided tape was used to attach sensors to the micro-expression capture locations on the eyelids, face, lips, etc., and then connected to a portable electrochemical workstation to complete the assembly of the overall micro-expression detection sensor. The electrochemical workstation was set to constant voltage current-time testing, with the constant voltage set to 0.05V.

[0217] Facial micro-expressions are the most direct and effective mode of emotion recognition, and an important means of communication between people. Real-time monitoring of facial micro-expressions has many applications, such as fatigue driving detection, medical applications, lie detection, and real-time facial expression recognition on mobile devices.

[0218] The pressure sensor of this invention is also suitable for monitoring different facial micro-expressions. The principle is that the recorded force change signal is attributed to the stress exerted by facial muscles on the pressure sensor, caused by facial muscle stretching, corresponding to changes in facial expression or blinking. The results of facial micro-expression changes and blinking are as follows... Figure 7 , 8 As shown, each peak corresponds to a change in facial expression from a smile to anger. Furthermore, the periorbital muscles, where changes are minimal, show a high degree of consistency between frontal and lateral monitoring results. If the packaging of the pressure sensor is improved, or if it can fit more closely to the entire face of the test subject for more sensitive identification of micro-expressions, this sensor could potentially be used as a lie detector based on the amplitude of muscle deformation, providing a reference for criminal investigation. By measuring the frequency and amplitude of blinks, blink tests could also be easily used to assess fatigue levels or overall health.

[0219] Application Example 3

[0220] This application example provides a chewing pressure sensor, which uses the Ti3C2T provided in Example 3. x The specific preparation of MXene-graphene oxide material includes: preparing Ti3C2T x The MXene-graphene oxide film was cut and connected to copper wires, then sealed with polyimide tape. Medical double-sided tape was used to attach the sensors to the cheeks and lips of the patient. Finally, the sensor was connected to a portable electrochemical workstation to complete the assembly of the overall chewing detection sensor. The electrochemical workstation was set to a constant voltage current-time test, with the constant voltage set to 0.05V.

[0221] This invention can be attached to the cheek to monitor human chewing data in real time, providing medical professionals with more accurate and efficient diagnoses and helping doctors design more suitable treatment plans. Based on the sensor's high sensitivity and its flexible surface that allows for good adhesion to muscle surfaces, this device monitors subtle muscle movements. The pressure sensor can be attached to the cheek for chewing analysis, such as the contraction and relaxation of muscles without specific exertion and swallowing actions. The chewing process test results are as follows... Figure 9 As shown, the intensity and time interval of a person's chewing reaction can be clearly observed. Then, based on big data, the system can provide the correct feedback to the human body and finally record it on a smartphone.

[0222] Application Example 4

[0223] This application example provides a pressure sensor for measuring heart rate, wherein the pressure sensor adopts the Ti3C2T provided in Example 1. x The specific preparation of MXene-graphene oxide material includes: preparing Ti3C2T x The MXene-graphene oxide film is cut to size and connected to copper wires, then sealed with polyimide tape. The sensor is attached to the neck and / or wrist using medical double-sided tape, and then connected to a portable electrochemical workstation to complete the pulse signal detection sensor assembly. The electrochemical workstation is set to a constant voltage current-time test, with the constant voltage set to 0.05V. The pressure sensor provided in this application example can be placed on the neck and / or wrist. This pressure sensor can monitor the pulse signals of the carotid and radial arteries in real time, and the objectively recorded pulse waveform helps doctors analyze pathological conditions more accurately. This invention allows the pressure sensor to be fixed to the neck and wrist with a bandage, providing a good response to arterial pulsation. Figure 10 It is a skin device installed on the carotid artery to monitor the neck pulse in real time as a vital sign. Figure 11 This is a pulse waveform image implanted on the artery in the left wrist. The peak of each cycle in the image represents the artery's pulsation, while the trough represents its contraction. Through counting and calculation, the test subject's pulse was consistently detected at approximately 67-68 beats per minute, demonstrating excellent reproducibility. Furthermore, the volunteers met healthy health standards. Comparing the pulse waveforms of the carotid and wrist arteries, the carotid artery waveform image is more realistic, with details closely matching the pulse. The amplitude of the carotid artery pulse is also greater than that of the wrist artery, both of which indirectly demonstrate the sensor's ability to detect pulse.

[0224] The present invention has been illustrated with the above embodiments to illustrate its detailed structural features. However, the present invention is not limited to the above detailed structural features, that is, it does not mean that the present invention must rely on the above detailed structural features to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions for the components used in the present invention, additions of auxiliary components, and selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A Ti3C2T x The method for preparing MXene-graphene oxide materials is characterized by, The preparation method includes: Hybrid Ti3C2T x The first mixture obtained from MXene dispersion and graphene oxide dispersion is subjected to a first stirring, followed by the addition of a precipitant for coagulation and a second stirring in a protective atmosphere. The resulting second mixture is then vacuum filtered and dried to obtain the Ti3C2T. x MXene-graphene oxide materials; The precipitant is hydrochloric acid.

2. The preparation method according to claim 1, characterized in that, The Ti3C2T x Ti3C2T in MXene dispersion and graphene oxide dispersion x The mass ratio of MXene to graphene oxide is 2~5:

1.

3. The preparation method according to claim 1, characterized in that, The Ti3C2T x Ti3C2T in MXene dispersion x The concentration of MXene is 0.5~1.5 g / L.

4. The preparation method according to claim 1, characterized in that, The concentration of graphene oxide in the graphene oxide dispersion is 0.5~1.5 g / L.

5. The preparation method according to claim 1, characterized in that, The protective atmosphere includes a nitrogen atmosphere and / or a helium atmosphere.

6. The preparation method according to claim 1, characterized in that, The first stirring speed is 400~800 rpm.

7. The preparation method according to claim 1, characterized in that, The first stirring time is 25~40 minutes.

8. The preparation method according to claim 1, characterized in that, The temperature of the first stirring was room temperature.

9. The preparation method according to claim 1, characterized in that, The pH of the system after the addition of the precipitant is 4.5~5.

5.

10. The preparation method according to claim 1, characterized in that, The concentration of the hydrochloric acid is 5~7 mol / L.

11. The preparation method according to claim 1, characterized in that, The second stirring speed is 400~800 rpm.

12. The preparation method according to claim 1, characterized in that, The second stirring time is 25~40 minutes.

13. The preparation method according to claim 1, characterized in that, The second stirring temperature is room temperature.

14. The preparation method according to claim 1, characterized in that, The vacuum filtration is performed using a water-based microporous filter membrane.

15. The preparation method according to claim 1, characterized in that, The drying process includes vacuum drying.

16. The preparation method according to claim 1, characterized in that, The drying temperature is 55~75℃.

17. The preparation method according to claim 1, characterized in that, The drying time is 15-30 minutes.

18. The preparation method according to claim 1, characterized in that, The Ti3C2T x The preparation of MXene dispersions includes: S11, mixed aluminum titanium carbide and fluorine source are dissolved in acid solution to carry out the first reaction to obtain the first reaction solution; S12. The first reaction solution obtained in step S11 is centrifuged at least twice until the solution pH is neutral to obtain the first centrifuged solid phase. S13, a mixed solvent and the first centrifuged solid phase from step S12 are subjected to ultrasonication and a second centrifugation to obtain a second centrifuged solid phase. The second centrifuged solid phase is then dried to obtain the Ti3C2TxMXene. S14, the Ti3C2T described in step S13 x MXene was dispersed in water to obtain the Ti3C2T. x MXene dispersion.

19. The preparation method according to claim 18, characterized in that, The fluorine source mentioned in step S11 includes lithium fluoride.

20. The preparation method according to claim 18, characterized in that, The acid solution includes hydrochloric acid.

21. The preparation method according to claim 18, characterized in that, The concentration of the acid solution is 8.5~9.5 mol / L.

22. The preparation method according to claim 18, characterized in that, The mass ratio of the fluorine source to the aluminum titanium carbide is 0.8 to 1:

1.

23. The preparation method according to claim 18, characterized in that, The solid-liquid ratio of the aluminum titanium carbide to the acid solution is 0.5~1.5:20g / mL.

24. The preparation method according to claim 18, characterized in that, The temperature of the first reaction is 38~42℃.

25. The preparation method according to claim 18, characterized in that, The first reaction takes 20-30 hours.

26. The preparation method according to claim 18, characterized in that, The first reaction was carried out under stirring.

27. The preparation method according to claim 18, characterized in that, The stirring speed for the first reaction is 400-600 rpm.

28. The preparation method according to claim 18, characterized in that, The number of times the first centrifugation is at least twice in step S12 is 2 to 8.

29. The preparation method according to claim 18, characterized in that, The pH range for neutrality is 5 to 7.

30. The preparation method according to claim 18, characterized in that, The solvent mentioned in step S13 includes water.

31. The preparation method according to claim 18, characterized in that, The power of the ultrasound is 200~400W.

32. The preparation method according to claim 18, characterized in that, The duration of the ultrasound is 0.5 to 1.5 hours.

33. The preparation method according to claim 18, characterized in that, The second centrifugation includes a first-stage centrifugation and a second-stage centrifugation.

34. The preparation method according to claim 33, characterized in that, The rotation speed of the first-stage centrifuge is 800~1200 r / min.

35. The preparation method according to claim 33, characterized in that, The first stage of centrifugation takes 15 to 30 minutes.

36. The preparation method according to claim 33, characterized in that, The rotation speed of the second-stage centrifuge is 5000~7000 r / min.

37. The preparation method according to claim 33, characterized in that, The second stage of centrifugation takes 30-50 minutes.

38. The preparation method according to claim 18, characterized in that, The drying process described in step S13 includes freeze drying.

39. The preparation method according to claim 38, characterized in that, The freeze-drying temperature is -30 to -40°C.

40. The preparation method according to claim 38, characterized in that, The freeze-drying time is 20-25 hours.

41. The preparation method according to claim 38, characterized in that, The absolute pressure of the freeze-drying process is 100 Pa to 200 Pa.

42. The preparation method according to claim 1, characterized in that, The preparation of the graphene oxide dispersion includes: S21. Phosphorus pentoxide and potassium persulfate are added sequentially to concentrated sulfuric acid. After the solution becomes clear, it is heated and cooled sequentially to obtain the first mixture. S22. Graphite is added to the first mixture to carry out the second reaction. The resulting second reaction material is cooled, precipitated by water precipitation and dried in sequence to obtain pre-oxidized graphite. S23. Add the pre-oxidized graphite and potassium permanganate described in step S22 to concentrated sulfuric acid in sequence, and obtain the third reaction solution after the third reaction. S24. The third reaction liquid described in step S23 is diluted and mixed with an oxidant, and then subjected to a fourth oxidation reaction. The resulting fourth oxidation reaction material is then cooled, separated from solids and liquids, washed, dialyzed and dried to obtain the graphene oxide. S25. The graphene oxide obtained in step S24 is dispersed in water to obtain the graphene oxide dispersion.

43. The preparation method according to claim 42, characterized in that, The solid-liquid ratio of phosphorus pentoxide and concentrated sulfuric acid in step S21 is 0.5~1.5:3 g / mL.

44. The preparation method according to claim 42, characterized in that, The mass ratio of phosphorus pentoxide to potassium persulfate is 0.8~1.2:

1.

45. The preparation method according to claim 42, characterized in that, The heating temperature is 75~85℃.

46. ​​The preparation method according to claim 42, characterized in that, The heating time is 2-4 hours.

47. The preparation method according to claim 42, characterized in that, Smoke is continuously emitted during the heating process.

48. The preparation method according to claim 42, characterized in that, In step S22, the solid-liquid ratio of graphite to the first mixture is 1:1.2~1.3 g / mL.

49. The preparation method according to claim 42, characterized in that, The temperature of the second reaction is 75~85℃.

50. The preparation method according to claim 42, characterized in that, The second reaction takes 2 to 4 hours.

51. The preparation method according to claim 42, characterized in that, The cooling time for the second reactant is 4-8 hours.

52. The preparation method according to claim 42, characterized in that, The water precipitation process includes mixing water and the second reactant and stirring, followed by solid-liquid separation.

53. The preparation method according to claim 52, characterized in that, The solid-liquid separation includes vacuum filtration.

54. The preparation method according to claim 52, characterized in that, The solid phase obtained from the solid-liquid separation is then washed with water until the pH of the filtrate is 6.8 to 7.

2.

55. The preparation method according to claim 42, characterized in that, The drying time in step S22 is 8~12 hours.

56. The preparation method according to claim 42, characterized in that, The drying temperature in step S22 is 60~80℃.

57. The preparation method according to claim 42, characterized in that, The solid-liquid ratio of the pre-oxidized graphite to concentrated sulfuric acid is 1:20~25 g / mL.

58. The preparation method according to claim 42, characterized in that, The mass ratio of potassium permanganate to pre-oxidized graphite is 0.5~1.5:

3.

59. The preparation method according to claim 42, characterized in that, In step S23, the pre-oxidized graphite and potassium permanganate described in step S22 are added to concentrated sulfuric acid sequentially at a temperature below 20°C.

60. The preparation method according to claim 42, characterized in that, The temperature of the third reaction is 30~45℃.

61. The preparation method according to claim 42, characterized in that, The third reaction takes 1 to 3 hours.

62. The preparation method according to claim 42, characterized in that, The third reaction is followed by dilution.

63. The preparation method according to claim 62, characterized in that, The dilution is carried out using water, and the volume ratio of water to the material after the third reaction is 1.8~2.5:

1.

64. The preparation method according to claim 42, characterized in that, The oxidant mentioned in step S24 is a hydrogen peroxide solution.

65. The preparation method according to claim 64, characterized in that, The concentration of the hydrogen peroxide solution is 15~40wt%.

66. The preparation method according to claim 42, characterized in that, The washing solution used in step S24 is hydrochloric acid.

67. The preparation method according to claim 42, characterized in that, The dialysis period is 6 to 10 days.

68. The preparation method according to claim 42, characterized in that, The drying process described in step S24 is freeze drying.

69. A Ti3C2T x MXene-graphene oxide material, characterized in that, The Ti3C2T x The MXene-graphene oxide material uses the Ti3C2T material as described in any one of claims 1 to 68. x The MXene-graphene oxide material was prepared by a specific method.

70. A Ti3C2T according to claim 69 x Applications of MXene (graphene oxide) materials in wearable pressure sensors or supercapacitors.

71. A detection device, characterized in that, The detection device includes the Ti3C2T as described in claim 69. x MXene-graphene oxide material.

72. The detection device according to claim 71, characterized in that, The detection device includes a motion detection device or a health monitoring device.

73. The detection device according to claim 72, characterized in that, The motion detection device includes any one or a combination of at least two of the following: a facial micro-expression detection device, a lip muscle detection device, an eye muscle detection device, or a chewing pressure detection device.

74. The detection device according to claim 72, characterized in that, The health monitoring device includes a heart rate detection device.

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