CN114940490A - A kind of preparation method of carbon nanotube/titanium dioxide flexible composite film - Google Patents

Abstract

The invention discloses a preparation method of a carbon nanotube/titanium dioxide flexible composite film. In this method, the flexible carbon nanotube (CNT) film is energized in the air, and the high Joule heat generated by the film is used to heat and oxidize the MXene supported on its surface to obtain titanium dioxide (TiO ₂ ), where the MXene material is a single layer or a few layers. of Ti ₃ C ₂ . Due to the high Joule heating temperature of CNT film, it has the characteristics of fast response, low energy consumption and wide controllable temperature range, which can be used to rapidly oxidize Ti ₃ C ₂ , thereby replacing the traditional physical pulverization, liquid or gas phase methods and other low-efficiency and energy-consuming methods. preparation method. However, the present invention can prepare a flexible CNT/TiO ₂ composite film by direct electric heating in a short time, the method has the advantages of energy saving and high efficiency, and has an important application prospect.

Description

A kind of preparation method of carbon nanotube/titanium dioxide flexible composite film

technical field

The invention belongs to the technical field of film material preparation, and in particular relates to a rapid preparation method of a carbon nanotube/TiO ₂ flexible composite film.

Background technique

Titanium dioxide has good catalytic performance and strong adsorption, and is widely used in photocatalysis, wastewater treatment, lithium-ion batteries, solar cells and other fields. It is also very suitable as a slow-release carrier in food, medicine, cosmetics and other fields. In the preparation of titanium dioxide, tetrabutyl titanate or metal nano-titanium particles are often used as titanium sources. The preparation processes are mostly physical pulverization, liquid phase, gas phase and other methods. Most of them are time-consuming, complex and there are many waste liquids, high energy consumption. For example, patent CN101339872B discloses a double-layer blended structure carbon nanotube thin film field emission cathode and its preparation method. Titanium nano-powder is blended to prepare CNT composite slurry, and a single-layer Ti blended structure is printed by screen technology. CNT cathode films. Through a two-step sintering process, a double-layer blended structure CNT composite film cathode is formed with the upper layer mixed with TiO ₂ and the lower layer with a Ti-mixed structure. Patent CN112007659A discloses a preparation method and product of a rare earth doped indium sulfide nanosheet/TiO ₂ composite photoanode film. Anhydrous ethanol and a titanium source are mixed to obtain a solution and an aqueous ethanol solution, and then diethanolamine is added, and it is allowed to stand for aging , get titania gel, prepare titania thin film by dipping and pulling method; dissolve thulium nitrate, ytterbium nitrate, indium source and sulfur source in deionized water to obtain a precursor solution, transfer it to the reaction kettle, and place the titania film against the reaction kettle In the process, heat preservation, cooling, taking out and drying to obtain the rare earth doped indium sulfide nanosheet/TiO ₂ composite photoanode film material. In this patent, butyl titanate is used to prepare a titanium dioxide film by a dip-pulling method. Patent CN112480649A discloses a titanium dioxide/TPU composite hydrophilic film and its preparation method. The titanium dioxide precursor is mixed and stirred with a solvent to obtain a TiO ₂ sol; the linseed oil and formic acid are stirred, and hydrogen peroxide, a hydroxyl compound and a catalyst are added. , obtain a hyperbranched linseed oil-based polyol; dehydrate the linseed oil-based polyol, add diisocyanate, TiO ₂ sol, and a small molecule chain extender to obtain TiO ₂ /TPU, dissolve it to obtain a casting liquid, and make it into into a thin film. In this patent, butyl titanate is used as the titanium source. To sum up, most of the existing patents use tetrabutyl titanate or titanium nano-powder as the titanium source, and use hydrothermal or traditional muffle furnace sintering to prepare TiO ₂ , which has many problems in energy consumption and environmental protection.

_The patent of the present invention uses _Ti3C2MXene as a titanium source, and utilizes the method of oxidizing _Ti3C2 by the rapid temperature rise generated by Joule heat of the flexible CNT film to rapidly prepare a carbon nanotube/titanium _dioxide flexible composite film. This method has the advantages of fast heating and high efficiency. _TiO2 nanoparticles can be synthesized in a short time, which saves a lot of time compared with traditional methods, and at the same time, the current and voltage required for the preparation process are low, which is beneficial to saving energy consumption.

SUMMARY OF THE INVENTION

In order to solve the shortcomings of the prior art, the present invention provides a preparation method of a carbon nanotube/titanium dioxide flexible composite film.

The present invention solves the above-mentioned technical problem through the following scheme:

Based on a preparation method of a carbon nanotube/titanium dioxide flexible composite film, a carbon nanotube film is used to generate Joule heat by electrifying it, and then the Joule heat of the CNT film is used to heat and rapidly oxidize MXene loaded on its surface in the air. The target carbon nanotube/titanium dioxide flexible composite film was obtained.

The Joule heat source includes, but is not limited to, pure carbon nanotube films, or composite films or fabrics of carbon nanotubes and graphite, graphene, or carbon fibers.

Among them, using the Ti element in MXene, the CNT/MXene film can be energized to quickly reach high temperature, and then the CNT/TiO ₂ composite film is synthesized.

Among them, the use of short-time temperature rise and small voltage and current has the advantages of saving energy consumption and high efficiency.

Based on a preparation method of a carbon nanotube/titanium dioxide flexible composite film, comprising the following steps:

(1) CNT film pretreatment: Cut a CNT film with a certain size and thickness of 5-100 microns, first soak it with concentrated nitric acid for 6 hours to remove impurities such as catalysts, and then wash it with deionized water and ethanol until neutral.

(2) Preparation of MXene solution: First, 1.2 g of lithium fluoride and 40 mL of hydrochloric acid were stirred in a polytetrafluoro beaker for 30 min, then ₂ g of _Ti3AlC2 raw material was slowly added to the beaker, and the stirring was continued at 35 °C for 24 minutes. h. Then, the above solution was centrifuged and washed several times until the solution became neutral, ethanol was added for 1 h, and the precipitate was collected by high-speed centrifugation. Finally, deionized water was added, shaken, and sonicated for 20 min, and then centrifuged at 3500 rpm for 3 min to obtain the MXene dispersion.

(3) Loading of MXene on the surface of the CNT film: Mix the MXene solution with anhydrous ethanol uniformly, and vacuum filter it onto the CNT film to obtain a surface-loaded MXene CNT film. The two ends of the composite film are further energized, and by controlling the voltage or current size and energization time, the Joule heat of the CNT film itself is used to rapidly oxidize MXene on the surface to obtain TiO ₂ nanoparticles, and finally carbon nanotubes/titanium dioxide are obtained. Flexible composite membrane.

The beneficial technologies that can be realized by the present invention at least include: oxidizing Ti ₃ C ₂ on the surface of the CNT film with Joule heat generated by electrifying the CNT film with rapid heating and cooling characteristics to synthesize nano-TiO ₂ , and traditional physical powder method, gas phase method , the liquid phase method and other high-energy-consumption and high-polluting ways to synthesize _TiO2 have significant advantages. This method has the characteristics of low energy consumption and high efficiency, especially the ultra-fast preparation of CNT thin film-supported _TiO2 nanoparticles can be realized in a few seconds, which has important commercial application prospects.

Description of drawings

FIG. 1 is a schematic diagram of the process of preparing nano-titanium dioxide on the surface of a carbon nanotube film by utilizing an ultrafast Joule heating temperature response in the present invention.

FIG. 2 is an optical photo of the flexible display of the carbon nanotube/titanium dioxide flexible composite film in the present invention.

FIG. 3 is a scanning electron microscope photograph of low-loaded nano-TiO ₂ particles prepared on the surface of a carbon nanotube film in an example of the present invention.

FIG. 4 is a scanning electron microscope photograph of the nano-TiO ₂ particles with high loading on the surface of the carbon nanotube film in the example of the present invention.

FIG. 5 is a scanning electron microscope photograph under high magnification of the nano-TiO ₂ particles prepared on the surface of the carbon nanotube film in the example of the present invention.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, but not all, examples of the invention. Based on the embodiments of the present invention, other embodiments obtained by persons of ordinary skill in the art without creative work shall fall within the protection scope of the present invention.

Example 1

A method for preparing a carbon nanotube/titanium dioxide flexible composite film, which uses the Joule heat generated by electrifying a carbon nanotube film, uses the Joule heat of the CNT film to heat, and rapidly oxidizes Ti ₃ C ₂ loaded on its surface in air. MXene, the target carbon nanotube/titanium dioxide flexible composite film was prepared.

A preparation method of a carbon nanotube/titanium dioxide flexible composite film, specifically comprising the following steps:

First, a 2×4 cm carbon nanotube film with a thickness of 10 microns was cut, and it was soaked in concentrated nitric acid for 6 h to remove impurities such as catalysts. 500 μL of Ti ₃ C ₂ MXene with a concentration of 1.5 mg/mL was mixed with 20 mL of anhydrous ethanol and filtered onto the carbon nanotube film to obtain a CNT film loaded with MXene. Then, the side containing MXene in the composite film is facing up, and the two ends of the composite film are adhered to the sample holder in the Joule heating furnace by using conductive silver glue. The CNT film was energized, and under a constant voltage of 6V, the surface of the CNT film reached 350 °C within 1 second, and the constant temperature was maintained for 30 seconds. At this time, the MXene on the surface of the CNT film was oxidized to TiO ₂ in the air, and the surface was uniformly distributed. CNT thin films of _TiO2 nanoparticles, i.e. carbon nanotube/titania flexible composite films.

Example 2

A method for preparing a carbon nanotube/titanium dioxide flexible composite film, which uses the Joule heat generated by electrifying a carbon nanotube film, uses the Joule heat of the CNT film to heat, and rapidly oxidizes Ti ₃ C ₂ loaded on its surface in air. MXene, the target carbon nanotube/titanium dioxide flexible composite film was prepared.

A preparation method of a carbon nanotube/titanium dioxide flexible composite film, specifically comprising the following steps:

First, a 2×4 cm carbon nanotube film with a thickness of 10 microns was cut, and it was soaked in concentrated nitric acid for 6 h to remove impurities such as catalysts. 500 μL of Ti ₃ C ₂ MXene with a concentration of 1 mg/mL was mixed with 20 mL of anhydrous ethanol, and then filtered onto the carbon nanotube film to obtain a CNT film loaded with MXene. Then, the side containing MXene in the composite film is facing up, and the two ends of the composite film are adhered to the sample holder in the Joule heating furnace by using conductive silver glue. The CNT film was energized, and under a constant voltage of 7V, the surface of the CNT film instantly reached 400 °C within 1 second, and the constant temperature was maintained for 20 seconds. At this time, the MXene on the surface of the CNT film was oxidized to TiO ₂ in the air, and a uniform surface was obtained. CNT thin films with _TiO nanoparticles distributed, i.e. carbon nanotube/titania flexible composite films.

Example 3

A method for preparing a carbon nanotube/titanium dioxide flexible composite film, which uses the Joule heat generated by electrifying a carbon nanotube film, uses the Joule heat of the CNT film to heat, and rapidly oxidizes Ti ₃ C ₂ loaded on its surface in air. MXene, the target carbon nanotube/titanium dioxide flexible composite film was prepared.

A preparation method of a carbon nanotube/titanium dioxide flexible composite film, specifically comprising the following steps:

First, a 2×4 cm carbon nanotube film with a thickness of 10 microns was cut, and it was soaked in concentrated nitric acid for 6 h to remove impurities such as catalysts. 500 μL of Ti ₃ C ₂ MXene with a concentration of 1 mg/mL was mixed with 20 mL of anhydrous ethanol, and then filtered onto the carbon nanotube film to obtain a CNT film loaded with MXene. Then, the side containing MXene in the composite film is facing up, and the two ends of the composite film are adhered to the sample holder in the Joule heating furnace by using conductive silver glue. The CNT film was energized, and under a constant voltage of 8V, the surface of the CNT film instantly reached 450 °C within 1 second, and the constant temperature was maintained for 10 seconds. At this time, the MXene on the surface of the CNT film was oxidized to TiO ₂ in the air, and a uniform surface was obtained. CNT thin films with _TiO nanoparticles distributed, i.e. carbon nanotube/titania flexible composite films.

Example 4

A method for preparing a carbon nanotube/titanium dioxide flexible composite film, which uses the Joule heat generated by electrifying a carbon nanotube film, uses the Joule heat of the CNT film to heat, and rapidly oxidizes Ti ₃ C ₂ loaded on its surface in air. MXene, the target carbon nanotube/titanium dioxide flexible composite film was prepared.

A preparation method of a carbon nanotube/titanium dioxide flexible composite film, specifically comprising the following steps:

First, a 2×4 cm carbon nanotube film with a thickness of 5 microns was cut and soaked in concentrated nitric acid for 6 h to remove impurities such as catalysts. 500 μL of Ti ₃ C ₂ MXene with a concentration of 1 mg/mL was mixed with 20 mL of anhydrous ethanol, and then filtered onto the carbon nanotube film to obtain a CNT film loaded with MXene. Then, the side containing MXene in the composite film is facing up, and the two ends of the composite film are adhered to the sample holder in the Joule heating furnace by using conductive silver glue. The CNT film was energized, and under a constant voltage of 6.5V, the surface of the CNT film instantly reached 400 °C within 1 second and maintained for 20 seconds. At this time, the MXene on the surface of the CNT film was oxidized to TiO ₂ in the air, and a uniform surface was obtained. CNT thin films with _TiO nanoparticles distributed, i.e. carbon nanotube/titania flexible composite films.

Example 5

A method for preparing a carbon nanotube/titanium dioxide flexible composite film, which uses the Joule heat generated by electrifying a carbon nanotube film, uses the Joule heat of the CNT film to heat, and rapidly oxidizes Ti ₃ C ₂ loaded on its surface in air. MXene, the target carbon nanotube/titanium dioxide flexible composite film was prepared.

A preparation method of a carbon nanotube/titanium dioxide flexible composite film, specifically comprising the following steps:

First, a 2×4 cm thick carbon nanotube film with a thickness of 20 microns was cut and soaked in concentrated nitric acid for 6 h to remove impurities such as catalysts. 500 μL of Ti ₃ C ₂ MXene with a concentration of 1 mg/mL was mixed with 20 mL of anhydrous ethanol, and then filtered onto the carbon nanotube film to obtain a CNT film loaded with MXene. Then, the side containing MXene in the composite film is facing up, and the two ends of the composite film are adhered to the sample holder in the Joule heating furnace by using conductive silver glue. The CNT film was energized, and under a constant current of 5 amperes, the surface of the CNT film instantly reached 450 °C within 1 second, and the constant temperature was maintained for 10 seconds. At this time, the MXene on the surface of the CNT film was oxidized to TiO ₂ in the air, and a uniform surface was obtained. CNT thin films with _TiO nanoparticles distributed, i.e. carbon nanotube/titania flexible composite films.

Compared with other preparation methods of TiO ₂ nanoparticles, the rapid preparation method of TiO ₂ nanoparticles of the present invention replaces the traditional physical pulverization method, liquid ionization method, and direct oxidation method by electrifying a CNT film with rapid heating and cooling characteristics to generate Joule heat. _TiO2 synthesis methods such as phase method/gas phase method. The method of the invention has the characteristics of low energy consumption and high efficiency, in particular, the ultra-fast preparation of the TiO ₂ nanoparticle thin film can be realized within a few seconds, and has important commercial application prospects.

Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, and substitutions can be made in these embodiments without departing from the principle and spirit of the invention and modifications, the scope of the present invention is defined by the appended claims and their equivalents.

Claims (7)

1. a preparation method of carbon nanotube/titanium dioxide flexible composite film, it is characterized in that: in the preparation process, described flexible composite film is to be energized at both ends of CNT film, utilize the Joule heat that film self resistance produces to make it rise. to the desired temperature and rapidly in situ oxidize MXenes on the surface of CNT thin films to achieve fast and efficient preparation of _TiO nanoparticles. 2. the preparation method of a kind of carbon nanotube/titanium dioxide flexible composite film according to claim 1, it is characterized in that: required energization voltage or electric current is lower, can make film rise to required amount in a short time in several seconds temperature and subsequent preparation are beneficial to reduce energy consumption. 3. The preparation method of a carbon nanotube/titanium dioxide flexible composite membrane according to claim 1, wherein the Joule heat source used in the preparation process of the composite membrane includes but is not limited to pure carbon nanotube films , or composite films or fabrics of carbon nanotubes with graphite, graphene or carbon fibers. 4 . The method for preparing a carbon nanotube/titanium dioxide flexible composite film according to claim 1 , wherein the MXene loading used in the preparation process of the composite film can vary according to the required TiO ₂ content And adjust. 5. the preparation method of a kind of carbon nanotube/titanium dioxide flexible composite film according to any one of claim 1～4, is characterized in that, comprising: 1) Pretreatment of CNT film: Cut a CNT film with a certain size and thickness of 5~100 microns, first soak it with concentrated nitric acid for 6 hours to remove impurities such as catalysts, and then wash it with deionized water and ethanol. sex; 2) Preparation of MXene solution: First, 1.2 g of lithium fluoride and 40 mL of hydrochloric acid were stirred in a polytetrafluoro beaker for 30 min, then ₂ g of _Ti3AlC2 raw material was slowly added to the beaker, and the stirring was continued at 35 °C for 24 h. Then, the above solution was centrifuged and washed several times until the solution became neutral, then ethanol was added to ultrasonic for 1 h, and then high-speed centrifugation was performed to collect the precipitate. min, MXene dispersion can be obtained; 3) Loading of MXene on the surface of the CNT film: Mix the MXene solution with anhydrous ethanol uniformly, and vacuum filter it onto the CNT film to obtain a surface-loaded CNT film with MXene, which is further electrified at both ends of the composite film and passed through By controlling the voltage or current and the energization time, the Joule heat of the CNT film itself is used to rapidly oxidize the surface MXene at high temperature to obtain TiO ₂ nanoparticles, and finally the carbon nanotube/titania flexible composite film is obtained. 6 . The preparation method of a carbon nanotube/titanium dioxide flexible composite film according to claim 5 , wherein the preparation method specifically comprises: 1) cutting a CNT film with a size of 2×4 cm and a thickness of 10 μm, Soak it with concentrated nitric acid for 6 hours to remove impurities such as catalysts, and then wash it with deionized water until neutral; 2) Etch to obtain 1 mg/mL MXene solution; 3) Measure 1 mL of MXene solution and 20 mL of absolute ethanol Mix evenly, vacuum filter onto the CNT film, and then stick the MXene-containing side of the composite film up, and use conductive silver glue to stick both ends to the sample holder in the Joule heating furnace; 4) For CNT/ The constant voltage of 6V was input to the MXene composite film, and the holding time was 30 seconds. The surface of the CNT film was about 350 °C. The Joule heat high temperature would rapidly oxidize the MXene on the surface and obtain _TiO2 nanoparticles, and then make carbon nanotubes/TiO2 flexible composite membrane. 7. The preparation method of a carbon nanotube/titanium dioxide flexible composite film according to claim 5, wherein the preparation method specifically comprises: 1) cutting a CNT film with a size of 2×4 cm and a thickness of 20 microns, Soak it with concentrated nitric acid for 6 hours to remove impurities such as catalysts, and then wash it with deionized water until neutral; 2) Etch to obtain 1 mg/mL MXene solution; 3) Measure 1 mL of MXene solution and 20 mL of absolute ethanol Mix evenly, vacuum filter onto the CNT film, and then stick the MXene-containing side of the composite film up, and use conductive silver glue to stick both ends to the sample holder in the Joule heating furnace; 4) For CNT/ The MXene composite film is fed with a constant current of 5 amps for 10 seconds, and the surface of the CNT film is about 450 °C. The high Joule heat will rapidly oxidize the MXene on the surface and obtain _TiO2 nanoparticles, and then make carbon nanotubes/TiO2 flexible composite membrane.

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