A stable dispersion of titanium carbide, preparation method and application

Abstract

The present invention relates to a stable titanium carbide dispersion, a preparation method and an application. Under water bath temperature conditions, the titanium carbide aluminum powder is selectively etched by an in-situ hydrofluoric acid generation method, the reactant is washed with water until neutral, and the upper layer of liquid is taken after ultrasonic centrifugation, which is a single-layer titanium carbide slurry; a certain amount of the single-layer titanium carbide slurry is added to different stabilizer solutions to obtain a stable dispersion of titanium carbide, which can be stored for a long time at room temperature. The present invention prepares titanium carbide nanosheets by an etching method, and utilizes the reducing property of the stabilizer itself to obtain a high-concentration titanium carbide dispersion with a concentration of up to 1.5% that is antioxidant and has good dispersibility. It can be stored at room temperature for up to half a year and still maintain good electronegativity. It can be used in smart wearable systems and supercapacitors to achieve devices that can maintain good performance and long-term stability.

Description

Technical Field

[0001] The invention relates to a high-concentration titanium carbide stable dispersion liquid, a preparation method and application thereof, and belongs to the technical field of material preparation and application. Background Art

[0002] Titanium carbide, as a typical member of the MXene family of two-dimensional transition metal carbonitrides, has been widely used in the fields of photothermal, sensors, batteries, catalysis, energy storage, electromagnetic shielding, etc. (see literature: Nature 2014, 516 , 78-81). However, titanium carbide nanosheets are extremely susceptible to oxidation, which leads to degradation of their two-dimensional structure and loss of functional properties. Titanium carbide nanosheets stored in aqueous solution will react with water molecules to produce titanium dioxide and amorphous carbon after being placed for a long time; in addition to titanium carbide dispersions, titanium carbide powders and devices based on titanium carbide will also lose their functionality after long-term exposure to air (see reference: Adv. Mater. Interfaces 2022, 9, 2200480). The current methods for anti-oxidation of MXene mainly focus on: (1) Preserving at low temperature or inert gas to reduce the generation of active oxygen groups (see reference: Chem. Mater. 2017, 29 , 4848−4856), but this limits the conditions for MXene treatment and the operating conditions of MXene-based equipment; (2) MXene dispersions are stored by introducing antioxidants, but according to current reports, the MXene concentration stored by them through antioxidants is low and the storage time is short (see reference: Adv. Mater. Interfaces 2020, 7, 2000845), which cannot meet the conditions for forming a conductive device. Therefore, developing a method to extend the functional life of titanium carbide nanosheets still faces great challenges.

[0003] Flexible wearable devices have attracted widespread attention because they retain the lightness, comfort and flexibility of traditional textiles while reasonably adding the high sensitivity, rapid response and intelligence of sensors. Among them, flexible wearable devices based on titanium carbide nanosheets occupy a large market. However, the titanium carbide dispersion is extremely easy to oxidize during use, resulting in poor performance. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a high-concentration titanium carbide stable dispersion liquid and a preparation method thereof, which have good dispersion stability and conductivity and can be stored for half a year at room temperature. The dispersion liquid can be added to textiles to construct an intelligent wearable system or a supercapacitor, thereby extending the long-term stability of its performance.

[0005] The technical solution to achieve the purpose of the present invention is to provide a method for preparing a stable dispersion of titanium carbide, comprising the following steps:

[0006] (1) Prepare a hydrochloric acid mixed solution with a lithium fluoride concentration of 1 to 5%;

[0007] (2) adding titanium aluminum carbide at a mass concentration of 1 to 5% to the mixed solution prepared in step (1), reacting at a temperature of 35 to 45°C for 20 to 30 hours to obtain a product;

[0008] (3) washing the product obtained in step (2) with water until neutral, ultrasonically treating it with anhydrous ethanol for 60 to 100 min, and then centrifuging it, dispersing it in deionized water and continuing to ultrasonically treat it for 10 to 30 min, and then centrifuging it at a speed of 2500 to 4000 rpm for 20 to 40 min, and then taking the upper layer liquid to obtain a monolayer titanium carbide slurry;

[0009] (4) The titanium carbide slurry prepared in step (3) is added dropwise to a composite stabilizer solution having a mass concentration of 0.01 to 0.5% to obtain a titanium carbide stable dispersion having a mass percentage of titanium carbide of 1 to 1.5%.

[0010] In step (4), the composite stabilizer comprises a composite solution of L(+)-ascorbic acid with a mass concentration of 60-70% and one or more of citric acid monohydrate, DL-tartaric acid, and L-cysteine ​​stabilizers.

[0011] The technical solution of the present invention comprises a stable dispersion of titanium carbide obtained according to the above preparation method.

[0012] And the application of the above-mentioned titanium carbide stable dispersion is to use it to prepare smart wearable systems and supercapacitors.

[0013] The high-concentration titanium carbide stable dispersion prepared by the present invention can be stored at room temperature for up to half a year, and can be used to process textiles to prepare intelligent wearable systems, or to prepare supercapacitors, so that the devices can maintain good performance and long-term stability.

[0014] Compared with modern technology, the beneficial effects of the present invention are as follows: the present invention provides a method for preparing and applying a high-concentration stable dispersion of titanium carbide that can be stored for a long time at room temperature, achieving efficient utilization, long-term stability and long-term high conductivity of titanium carbide nanosheets, and adding them to textiles can construct intelligent wearable systems or supercapacitors, which can extend the long-term stability of their performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1Transmission electron micrographs of the 1.3% mass concentration titanium carbide stable dispersion prepared in Example 1 of the present invention after being placed at room temperature for 0 days and 180 days.

[0016] Figure 2 X-ray diffraction patterns of the stable titanium carbide dispersion with a mass concentration of 1.3% prepared in Example 1 of the present invention after being placed at room temperature for 0 days and 180 days.

[0017] Figure 3 The liquid zeta potential diagram of the stable titanium carbide dispersion with a mass concentration of 1.3% prepared in Example 1 of the present invention after being placed at room temperature for 0 days and 180 days.

[0018] Figure 4 This is a graph of ultraviolet absorbance of a 1.3% mass concentration titanium carbide stable dispersion prepared in Example 1 of the present invention after being placed at room temperature for 0 days and 180 days. Implementation

[0019] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments. Example 1

[0020] Use a polytetrafluoroethylene beaker to prepare 50 ml of 9 mol / l hydrochloric acid solution, weigh 2.5 g of lithium fluoride and dissolve it in the hydrochloric acid solution. Stir it magnetically for 10 minutes to fully dissolve it. Slowly add 2.5 g of titanium carbide aluminum powder (400 mesh) to the lithium fluoride / hydrochloric acid solution within 15 minutes. Control the powder addition rate to prevent the generation of a large number of bubbles. Stir it magnetically at 45 ° C for 24 hours. After the reaction is completed, the reaction product is centrifuged and washed with deionized water several times until the pH is greater than 6. The precipitate is dispersed in 100 ml of anhydrous ethanol and centrifuged after ultrasonication for 1 hour. Then disperse the precipitate obtained at this time in 100 ml of deionized water and ultrasonicate for 30 minutes. Finally, the upper titanium carbide slurry is obtained after centrifugation at 3500 rpm for 20 minutes.

[0021] A composite stabilizer solution of L(+)-ascorbic acid / L-cysteine ​​(mass ratio 9:1) with a mass fraction of 0.4% was prepared, and the titanium carbide slurry prepared above was added to the L(+)-ascorbic acid / L-cysteine ​​stabilizing solution to obtain a titanium carbide stability dispersion, which was sealed, shaken, and stored at room temperature (mass concentration of titanium carbide was 1.3%).

[0022] By diluting the prepared titanium carbide stable dispersion to 0.8% and finishing the traditional fabric, a wearable device with fast response, conductivity and lightweight can be obtained.

[0023] See attached Figure 1, which are transmission electron micrographs of the titanium carbide stable dispersion prepared in this example: (a) shows the morphology of a single-layer titanium carbide nanosheet placed at room temperature for 0 days, and (b) shows the morphology of a single-layer titanium carbide nanosheet placed at room temperature for 180 days. It can be seen that the titanium carbide nanosheet has not been oxidized after being stored at room temperature for 180 days and is still well preserved.

[0024] See attached Figure 2 , are the X-ray diffraction patterns of the titanium carbide stability dispersion prepared in this example after being placed at room temperature for 0 days and 180 days: it can be seen that the titanium carbide nanosheets not sealed with a stabilizer have been completely oxidized after 180 days and a large number of characteristic peaks of titanium dioxide have appeared, while the titanium carbide nanosheets stored with a stabilizer are not much different from the newly prepared titanium carbide nanosheets.

[0025] See attached Figure 3 , which is the liquid Zeta potential diagram of the titanium carbide stability dispersion prepared in this example after being placed at room temperature for 0 days and 180 days: It shows that the titanium carbide nanosheets stored with the stabilizer still maintain good electronegativity.

[0026] See attached Figure 4 , is a comparison chart of the ultraviolet absorbance of the titanium carbide stability dispersion prepared in this example after being placed at room temperature for 0 days and 180 days: the titanium carbide nanosheets stored with a stabilizer can reach a maximum ultraviolet absorbance of 0.9 after being diluted to 10 ppm, while the ultraviolet absorbance of the titanium carbide nanosheets stored without a stabilizer after being diluted to 10 ppm is close to 0, with almost no absorption. Example 2

[0027] Use a polytetrafluoroethylene beaker to prepare 50 ml of 9 mol / l hydrochloric acid solution, weigh 2 g of lithium fluoride and dissolve it in the hydrochloric acid solution. Stir it magnetically for 10 minutes to fully dissolve it. Slowly add 2 g of titanium carbide aluminum powder (400 mesh) to the lithium fluoride / hydrochloric acid solution within 15 minutes. Control the powder addition rate to prevent the generation of a large number of bubbles. Stir it magnetically at 40 ° C for 20 hours. After the reaction is completed, centrifuge the reaction product and wash it with deionized water several times until the pH is greater than 6. Disperse the precipitate in 100 ml of anhydrous ethanol and centrifuge it after ultrasonication for 1 hour. Then disperse the precipitate obtained at this time in 100 ml of deionized water and ultrasonicate it for 30 minutes. Finally, obtain the upper titanium carbide slurry after centrifugation at 3500 rpm for 30 minutes.

[0028] A composite stabilizer solution of L(+)-ascorbic acid / L-cysteine ​​(mass ratio 9:1) with a mass fraction of 0.3% was prepared, and the titanium carbide slurry prepared above was added to the L(+)-ascorbic acid / L-cysteine ​​stabilizing solution to obtain a titanium carbide stable dispersion, which was sealed, shaken, and stored at room temperature (mass concentration of titanium carbide was 1.4%).

[0029] The prepared titanium carbide stable dispersion is diluted to 0.7% with water and then used to finish traditional fabrics to obtain wearable devices with fast response, conductivity and lightweight. Example 3

[0030] Use a polytetrafluoroethylene beaker to prepare 50 ml of 9 mol / l hydrochloric acid solution, weigh 1.5 g of lithium fluoride and dissolve it in the hydrochloric acid solution. Stir it magnetically for 10 minutes to fully dissolve it. Slowly add 1.5 g of titanium carbide aluminum powder (400 mesh) to the lithium fluoride / hydrochloric acid solution within 15 minutes. Control the powder addition rate to prevent the generation of a large number of bubbles. Stir it magnetically at 35 ° C for 24 hours. After the reaction is completed, centrifuge the reaction product and wash it with deionized water several times until the pH is greater than 6. Disperse the precipitate in 100 ml of anhydrous ethanol, ultrasonicate for 1 hour, and then centrifuge. Disperse the precipitate obtained at this time in 100 ml of deionized water and ultrasonicate for 30 minutes. Finally, centrifuge at 3500 rpm for 35 minutes to obtain the upper titanium carbide slurry.

[0031] A composite stabilizer solution of L(+)-ascorbic acid / / DL-tartaric acid solution (mass ratio 9:1) with a mass fraction of 0.35% was prepared, and the titanium carbide slurry prepared above was added to the L(+)-ascorbic acid / DL-tartaric acid composite stabilizing solution to obtain a titanium carbide stability dispersion, which was sealed, shaken and stored at room temperature (mass concentration of titanium carbide was 1.1%).

[0032] The prepared titanium carbide stable dispersion is diluted with water to 0.55% and the traditional fabric is finished to obtain a wearable device with fast response, conductivity and lightweight. Example 4

[0033] Use a polytetrafluoroethylene beaker to prepare 50 ml of 9 mol / l hydrochloric acid solution, weigh 1 g of lithium fluoride and dissolve it in the hydrochloric acid solution. Stir it magnetically for 10 minutes to fully dissolve it. Slowly add 1 g of titanium carbide aluminum powder (400 mesh) to the lithium fluoride / hydrochloric acid solution within 15 minutes. Control the powder addition rate to prevent the generation of a large number of bubbles. Stir it magnetically at 35 ° C for 24 hours. After the reaction is completed, centrifuge the reaction product and wash it with deionized water several times until the pH is greater than 6. Disperse the precipitate in 100 ml of anhydrous ethanol, ultrasonicate for 1 hour, and then centrifuge. Then disperse the precipitate obtained at this time in 100 ml of deionized water and ultrasonicate for 30 minutes. Finally, after centrifugation at 3500 rpm for 40 minutes, obtain the upper titanium carbide monolayer dispersion.

[0034] A composite stabilizer solution of L(+)-ascorbic acid / / L-cysteine / monohydrate citric acid (mass ratio 8:1:1) with a mass fraction of 0.35% was prepared, and the titanium carbide slurry prepared above was added to the composite stabilizer solution of L(+)-ascorbic acid / L-cysteine / monohydrate citric acid to obtain a titanium carbide stability dispersion, which was sealed, shaken and stored at room temperature (mass concentration of titanium carbide was 1.1%).

[0035] By diluting the prepared titanium carbide stable dispersion to 0.55% and finishing traditional fabrics, wearable devices with fast response, conductivity and lightweight can be obtained.

Claims

1. A method for preparing a stable dispersion of titanium carbide, characterized in that The following steps are involved: (1) Prepare a hydrochloric acid mixed solution with a lithium fluoride concentration of 1 to 5%; (2) adding titanium aluminum carbide at a mass concentration of 1 to 5% to the mixed solution prepared in step (1), reacting at a temperature of 35 to 45°C for 20 to 30 hours to obtain a product; (3) washing the product obtained in step (2) with water until neutral, ultrasonically treating it with anhydrous ethanol for 60 to 100 min, and then centrifuging it, dispersing it in deionized water and continuing to ultrasonically treat it for 10 to 30 min, and then centrifuging it at a speed of 2500 to 4000 rpm for 20 to 40 min, and then taking the upper layer liquid to obtain a monolayer titanium carbide slurry; (4) adding the titanium carbide slurry prepared in step (3) dropwise into a composite stabilizer solution having a mass concentration of 0.01 to 0.5% to obtain a titanium carbide stable dispersion having a mass percentage of titanium carbide of 1 to 1.5%; In step (4), the composite stabilizer comprises a composite solution of L(+)-ascorbic acid with a mass concentration of 60-70% and one or more of citric acid monohydrate, DL-tartaric acid, and L-cysteine ​​stabilizers.

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