A carbon nanotube preparation system and a single-walled carbon nanotube preparation process

Abstract

The present application relates to a kind of carbon nanotube preparation system and single-wall carbon nanotube preparation process, it is related to carbon nanotube material preparation technical field.The carbon nanotube preparation system of the present application includes: liquid sample introduction system, atomization chamber, pressure control system, gas inlet, furnace body, collection tank and tail gas treatment device;Wherein, liquid sample introduction system, atomization chamber, furnace body, collection tank, tail gas treatment device are sequentially communicated by pipeline;Pressure control system is set to atomization chamber outside;Gas inlet is communicated with atomization chamber;The pipeline end that atomization chamber is passed into furnace body is connected with flaring mouth.The present application can realize the continuous production of carbon nanotube on the basis of the above preparation system, improves the quality and stability of product, and can realize the high-yield preparation of high-quality single-wall carbon nanotube in combination with specific preparation process.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of carbon nanotube material preparation, in particular to a carbon nanotube preparation system and a single-walled carbon nanotube preparation process. BACKGROUND

[0002] Carbon nanotube materials have great application potential in the fields of electron transmission, heat transmission, mechanical performance and electromagnetic wave absorption, providing new possibilities for scientific research and industrial application in many fields. In the field of electron transmission, carbon nanotubes have excellent electrical conductivity and electrical properties, and can be used as one of the basic elements of high-performance electronic devices. Due to their ultra-thin and high surface charge density, carbon nanotubes can also be used to prepare flexible electronic devices, such as flexible displays and wearable devices. In the field of heat transmission, carbon nanotubes have excellent thermal conductivity and can be used as high-performance heat dissipation materials for heat dissipation and heat management of electronic devices, effectively improving the working stability and life of the devices. In the field of mechanical performance, carbon nanotubes have extremely high strength and stiffness, which can enhance the mechanical performance of composite materials. Adding an appropriate amount of carbon nanotubes can significantly improve the tensile strength, stiffness and wear resistance of the material, and thus be applied to the fields of automobile tires, aerospace materials, etc. As an electromagnetic wave absorption material, carbon nanotubes have a wide frequency band absorption capacity, especially in the military field. Carbon nanotubes can be used to prepare radar stealth materials, electromagnetic wave absorption coatings, etc., which can help improve the stealth performance and detection recognition ability of military equipment. In the field of chip preparation, traditional silicon materials are gradually approaching their physical limits, while carbon nanotubes have excellent electrical properties and size controllability and are considered as one of the candidates for the next generation of chip materials. Carbon nanotubes can be used to prepare nanoscale transistors, thermoelectric devices, etc., and are expected to promote the development of microelectronic technology.

[0003] Floating catalytic chemical vapor deposition is a potential macro-preparation process for preparing high-quality single-walled carbon nanotubes and few-walled carbon nanotubes. Floating catalytic chemical vapor deposition is a potential macro-preparation process for preparing high-quality single-walled carbon nanotubes and few-walled carbon nanotubes. The method co-injects carbon source gas and catalyst pre-driven particles into a high-temperature furnace, and the carbon source gas is catalytically decomposed on the catalyst to generate carbon nanotubes. The catalyst particles are in the gas phase together with the carbon source gas, which can continuously provide new catalytically active centers throughout the reaction process, promoting the growth of carbon nanotubes, thereby achieving high-yield preparation. Floating catalytic chemical vapor deposition can control the structure and quantity of carbon nanotubes by adjusting the ratio of carbon source gas and catalyst, and is expected to realize the macro-preparation of single-walled carbon nanotubes and few-walled carbon nanotubes. The temperature, time and other reaction conditions of the reaction can be controlled to realize accurate control of the quality and structure of carbon nanotubes.

[0004] Floating catalytic chemical vapor deposition method has relatively low cost and high scalability, and can be industrialized production. However, at present, the research on floating catalytic chemical vapor deposition method is still in the primary stage, and there are still some problems to be solved in practical application. For example, the design and optimization of catalyst need to be further studied to improve the quality and yield of carbon nanotubes. In addition, the separation and purification of carbon nanotubes need to be solved to obtain high-purity products. In general, although the macro preparation process of carbon nanotubes still faces challenges, floating catalytic chemical vapor deposition method as a promising method has the potential to make breakthroughs in this field and promote the large-scale application research and development of carbon nanotubes. SUMMARY

[0005] The purpose of the present application is to provide a carbon nanotube preparation system and a single-walled carbon nanotube preparation process to solve the problems existing in the prior art and realize high-yield and high-quality preparation of single-walled carbon nanotubes.

[0006] To achieve the above purpose, the present application provides the following solutions:

[0007] One of the technical solutions of the present application: a carbon nanotube preparation system is provided, comprising: a liquid sample introduction system, an atomization chamber, a pressure control system, an air inlet, a furnace body, a collection tank and an exhaust treatment device;

[0008] The liquid sample introduction system, the atomization chamber, the furnace body, the collection tank and the exhaust treatment device are sequentially connected by pipelines;

[0009] The air inlet is communicated with the atomization chamber;

[0010] The pressure control system is arranged outside the atomization chamber and is used to pressurize the carrier gas entering the atomization chamber through the air inlet;

[0011] The end of the pipeline connected to the atomization chamber into the furnace body is connected with a horn mouth.

[0012] The second technical solution of the present application: a continuous carbon nanotube preparation system is provided, and the above carbon nanotube preparation system is used as a repeating unit, and the exhaust treatment device of the previous repeating unit is communicated with the air inlet of the next repeating unit.

[0013] The number of repeating units is greater than or equal to 2, and preferably the number of repeating units is 2.

[0014] The diameter of the upper end opening of the horn mouth is equal to the diameter of the feeding pipeline, and the diameter of the lower end opening is less than or equal to the internal diameter of the furnace body and greater than the diameter of the upper end opening.

[0015] The top end of the atomization chamber is provided with an atomizer, and the bottom of the atomization chamber is provided with a heating jacket.

[0016] An atomizer and an atomizing chamber are arranged before the trumpet-shaped inlet to gasify and re-inject the raw material into the trumpet-shaped inlet. Meanwhile, the bottom end of the trumpet-shaped inlet is designed as an expanding pipeline, so that the gas flow gradually expands the pipe diameter when entering the growth pipe from the gas inlet pipe, so as to reduce the generation of vortex and the possibility of product adhesion. Through the design of the gradually expanding pipeline, the pipe diameter of the gas raw material at the trumpet-shaped inlet can be gradually increased, so that the gas backflow phenomenon is reduced, and the phenomenon that the growing carbon nanotubes adhere and stack in the low-temperature zone to cause poor product quality. The design method of gradually expanding the pipe diameter of the trumpet-shaped inlet can also stabilize the gas flow and control the flow rate, so as to ensure the uniformity and stability of the feeding process. Secondly, the pipeline between the discharge port furnace body and the collection box is improved, and a long temperature buffer area is arranged at the outlet of the furnace pipe, so that the generated single-walled carbon nanotube product is collected under the condition that the temperature gradually decreases, so as to reduce the possibility of adhesion in the metal pipe wall.

[0017] A fine metal mesh is arranged in the collection box, which can make the generated single-walled carbon nanotube aerogel film more easily fall off, and in addition, the frequency of periodic sampling is reduced.

[0018] In the present application, the pressure control system is composed of sensors, controllers, actuators and feedback loops, and the functions include pressure measurement, pressure monitoring, pressure regulation, pressure protection and automatic control. The pressure control system plays an important role in ensuring the stable and controllable operation of the system pressure.

[0019] The gas inlet can ensure the gas supply, realize the gas mixing and provide safety protection.

[0020] The atomizing chamber can introduce liquid in a proper way and disperse the liquid into fine particles or mist through a sprayer or other devices. This helps to increase the liquid surface area, improve the contact area with the environment, facilitate the volatilization of the solvent, the interaction of the reactants and the reaction, thereby promoting the diffusion and reaction of the substances. The atomizer is a device that mainly converts liquid into fine particles or droplets through ultrasonic waves, compressed air or mechanical vibration, and is the core component in the atomizing chamber.

[0021] The heating jacket can provide sufficient temperature for the liquid atomization to form gas.

[0022] The flange is used for the connection between the pipe ends and the connection between the equipment inlet and outlet.

[0023] The furnace body has the functions of high-temperature treatment, temperature control, heat preservation, safety protection and the like, and can meet various high-temperature manufacturing and processing requirements, thereby providing high-temperature reaction conditions for the preparation of single-walled carbon nanotubes.

[0024] Collection boxes can collect samples at the source or during preparation for subsequent analysis and processing. Furthermore, collection boxes provide a suitable storage environment to ensure the safety and stability of the samples.

[0025] Exhaust gas treatment devices typically reduce the concentration of highly disruptive gases such as sulfur dioxide to ensure the effectiveness and stability of the gas supply system, and can purify the gas to enable the recycling of carrier gas.

[0026] The flared mouth is made of aluminum oxide; the pipe is made of quartz.

[0027] The flared opening can prevent liquid samples from entering the high-temperature circuit body with the carrier gas and generating a vortex effect, which would otherwise cause poor-quality samples to deposit at the upper end of the high-temperature furnace tube.

[0028] More specifically, the steps for using the liquid injection system are as follows:

[0029] (1) Sample preparation: Prepare the liquid sample to be injected according to the preparation requirements. Ensure that the sample has been pretreated or prepared.

[0030] (2) Connecting the system: Connect the liquid injection system to the other components. Ensure the connection is correct and secure.

[0031] (3) Set injection parameters: Set parameters such as injection volume and injection speed. Liquid injection systems are usually equipped with control panels or software, which can be used to easily set and adjust parameters.

[0032] (4) Calibration system: The system can be calibrated according to the preparation requirements. Check the accuracy and stability of the liquid injection system to ensure the accuracy of the injection volume and rate.

[0033] (5) Sample injection: According to the preparation requirements and set parameters, insert the injection device into the liquid injection system. Introduce the sample into the injection device, ensuring there are no air bubbles, and insert the injection device into the corresponding position in the liquid injection system.

[0034] The third technical solution of this invention provides a process for preparing single-walled carbon nanotubes, using the above-mentioned carbon nanotube preparation system; the preparation process includes the following steps:

[0035] The furnace body temperature is set to 800-1300℃. Carrier gas is introduced into the carbon nanotube preparation system through the air inlet. The reaction raw materials are added to the liquid injection system and atomized through the atomization chamber, and then enter the furnace body through the flare.

[0036] The reaction products are collected using the collection box, and the exhaust gas is treated using the exhaust gas treatment device.

[0037] The pressure control system is used to control the pressure of the atomization chamber to be 10-100 atm during the preparation process.

[0038] The fourth aspect of the present application provides a continuous preparation process of carbon nanotubes, which uses the above-mentioned continuous preparation system of carbon nanotubes; the preparation process comprises the following steps:

[0039] The temperature inside the furnace body is set to be 800-1300℃, the carrier gas is introduced into the continuous preparation system of carbon nanotubes through the gas inlet, the reaction raw material is added into the liquid sample introduction system, and is atomized through the atomization chamber, and then enters the furnace body through the horn mouth.

[0040] The reaction product is collected by the collection box, and the tail gas is treated by the tail gas treatment device.

[0041] The pressure control system is used to control the pressure of the atomization chamber to be 10-100 atm during the preparation process.

[0042] The tail gas treated by the tail gas treatment device enters the gas inlet of the next repeating unit to continuously prepare carbon nanotubes.

[0043] As a further preferred embodiment of the present application, the reaction raw material used in the preparation process is a mixed solution of liquid carbon source, iron salt and sulfur source; the carrier gas is a mixed gas of hydrogen and nitrogen with a volume ratio of 2:1. The flow rate is preferably 100-600 μL / min during the preparation process.

[0044] The liquid carbon source includes ethanol, toluene, cyclohexane or other liquid carbon-containing organic matter; the iron salt acts as a catalyst, specifically one or more of ferric chloride, ferrous chloride, ferric acetate, ferric nitrate and ferrocene; the sulfur source acts as a co-catalyst, specifically thiophene, ethyl mercaptan, ethyl sulfide, sulfide and other compounds that can provide sulfur source.

[0045] Toluene is preferably used as the liquid carbon source, ferrocene or ferric chloride is used as the iron salt, and thiophene is used as the sulfur source.

[0046] The liquid carbon source, iron salt and sulfur source are mixed in a ratio of 100 mL:5 g:10 mL.

[0047] The liquid sample introduction system of the present application introduces the pretreated liquid sample in a precise and controllable manner, realizes automatic sample introduction through sample volume control and sample speed control, and improves experimental efficiency.

[0048] The tail gas generated in the preparation process of carbon nanotubes is introduced into the sodium hydroxide solution of the tail gas treatment device. Since the tail gas contains impurities such as sulfur dioxide, the sulfur dioxide impurities can be removed by introducing the tail gas into the sodium hydroxide solution for absorption and reaction.

[0049] The present application discloses the following technical effects:

[0050] The present application can optimize the gas flow in the preparation process of carbon nanotubes. By gradually expanding or narrowing the pipe diameter, the flow rate and flow state of the gas flow are adjusted, the generation of vortex is reduced, the possibility of product blockage is reduced, the gas can flow smoothly by reasonable design of the pipe structure, and the chaos and blockage of the gas flow are avoided.

[0051] The present application is aimed at the continuous preparation of carbon nanotubes. By connecting the preparation systems in series, the production efficiency can be improved, the waste of energy and materials can be reduced, the labor operation and management cost can be reduced, the product quality and consistency can be improved. The use of series can better control and monitor the production process, timely find and solve problems, improve the quality and stability of the product, and is an effective production optimization method.

[0052] The present application solves the problem of product adhesion in the pipe during the preparation process of carbon nanotubes, improves the production efficiency of carbon nanotubes, and further meets the production demand of carbon nanotubes in industry. The preparation system and method of the present application can prepare high-yield and high-quality single-walled carbon nanotubes (G / D value can reach more than 50). BRIEF DESCRIPTION OF DRAWINGS

[0053] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0054] Figure 1 It is a schematic diagram of the preparation system of single-walled carbon nanotubes in the embodiments of the present application. Wherein: 1. liquid sample introduction system, 2. gas inlet, 3. pressure control system, 4. atomization chamber, 5. atomizer, 6. heating jacket, 7. flange, 8. horn mouth, 9. high-temperature furnace body, 10. collection box, 11. tail gas treatment device;

[0055] Figure 2 It is the Raman spectrum of the product obtained in Example 1 of the present application;

[0056] Figure 3 It is the scanning electron microscope image of the product obtained in Example 1 of the present application;

[0057] Figure 4 It is the Raman spectrum of the product obtained in Example 2 of the present application;

[0058] Figure 5 It is the scanning electron microscope image of the product obtained in Example 2 of the present application. DETAILED DESCRIPTION

[0059] Various exemplary embodiments of the present application will now be described in detail, with reference to the drawings. These embodiments are described only by way of illustrating the present application, and should not be considered to limit the scope of the present application, but to be understood as a more detailed description of certain aspects, features and embodiments of the present application.

[0060] It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application. In addition, for any numerical limits recited herein, these numerical limits are approximations. Although these numerical limits are approximations, the numerical limits are indicated with a degree of precision that is not exact. Any numerical limit should at least be construed in light of this statement as permitting some

[0061] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present application, the preferred methods and materials are described. All patents, patent applications, publications, and descriptions mentioned herein are incorporated by reference to disclose and describe the methods and / or materials in connection with which the patents, patent applications, publications, and descriptions are cited.

[0062] Many modifications and variations of this application can be made in the light of the above teachings without departing from the spirit and scope thereof, and it is to be understood that all such modifications and variations warrant the patentable subject matter under the patent laws. Other embodiments of the application will be apparent to those skilled in the art from consideration of the specification and practice of the application disclosed herein. For example, the specification can be used to design other devices that are similar to the device described herein. The specification and examples given herein are exemplary only. It is to be understood that the scope of the application encompasses other applications that can be derived from the disclosure.

[0063] As used herein, the terms "comprise", "comprising", "include", "including", "have", "having" and the like are open-ended and do not exclude additional elements or steps.

[0064] Figure 1 A schematic diagram of a system for preparing single-walled carbon nanotubes in an embodiment of the present application.

[0065] Example 1

[0066] The temperature in the furnace 9 is regulated to 1300°C, then a mixed gas of hydrogen and nitrogen with a volume ratio of 2:1 is introduced as carrier gas (100 μL / min) from the gas inlet 2, and a mixed solution of toluene, ferrocene and thiophene (toluene: ferrocene: thiophene = 100 mL: 5 g: 10 mL) is added into a syringe, the mixed solution in the syringe is introduced into the preparation system by using the liquid sampling system 1, the mixed solution is atomized in the atomization chamber 4 after passing through the atomizer 5 (heating treatment is performed by the heating jacket 6), and then is mixed with the carrier gas, and then is introduced into the furnace 9 through the pipe at the horn mouth 8, and is uniformly diffused in the process of downward transmission. Single-walled carbon nanotube aerogel is generated by the reaction, and the reaction product is discharged from the lower end of the furnace 9 (the temperature of this part is higher than 800°C), and is introduced into the collection tank 10, and the tail gas is introduced into the tail gas treatment device 11 (sodium hydroxide solution with a concentration of 0.3 M) and is sequentially connected to two machines for reaction and treatment.

[0067] In the above preparation process of single-walled carbon nanotubes, the pressure in the atomization chamber is maintained at 10-100 atm by the pressure control system 3.

[0068] The Raman spectrum of the obtained product is shown in Figure 2 The G / D = 71, and the product has a clear RBM peak, which indicates that the product is high-quality single-walled carbon nanotubes (SWCNT-1); the scanning electron microscope image of the product is shown in Figure 3 The product is slender and pure, and is uniformly distributed.

[0069] Example 1 consumes 1 g of ferrocene to produce 0.3-0.4 g of single-walled carbon nanotubes.

[0070] Example 2

[0071] The temperature in the furnace 9 is regulated to 1300°C, then a mixed gas of hydrogen and nitrogen with a volume ratio of 2:1 is introduced as carrier gas (100 μL / min) from the gas inlet 2, and a mixed solution of toluene, ferrocene and thiophene (toluene: ferrocene: thiophene = 100 mL: 5 g: 10 mL) is added into a syringe, the mixed solution in the syringe is introduced into the preparation system by using the liquid sampling system 1, the mixed solution is atomized in the atomization chamber 4 after passing through the atomizer 5 (heating treatment is performed by the heating jacket 6), and then is mixed with the carrier gas, and then is introduced into the furnace 9 through the pipe at the horn mouth 8, and is uniformly diffused in the process of downward transmission. Single-walled carbon nanotube aerogel is generated by the reaction, and the reaction product is discharged from the lower end of the furnace 9 (the temperature of this part is higher than 800°C), and is introduced into the collection tank 10, and the tail gas is introduced into the tail gas treatment device 11 (sodium hydroxide solution with a concentration of 0.3 M) and is sequentially connected to two machines for reaction and treatment.

[0072] In the above preparation process of single-walled carbon nanotubes, the pressure in the atomization chamber is maintained at 10-100 atm by the pressure control system 3.

[0073] The Raman spectrum of the obtained product is shown inFigure 4 As shown, G / D = 128, and has obvious RBM peak, indicating that the product is high-quality single-walled carbon nanotube (SWCNT-2); the scanning electron microscope photograph of the product is as shown in Fig. 2. Figure 5 As shown, the product is slender and pure, and is uniformly distributed.

[0074] Example 2 consumes 1 g of ferrocene to produce 0.3-0.4 g of single-walled carbon nanotube.

[0075] The above-described examples are only used to describe the preferred modes of the present application, and do not limit the scope of the present application. Without departing from the design spirit of the present application, various modifications and improvements to the technical solutions of the present application made by those skilled in the art shall fall within the protection scope determined by the claims of the present application.

Claims

1. A process for the preparation of single-walled carbon nanotubes, characterized in that, The carbon nanotube preparation system comprises a liquid sample feeding system, an atomization chamber, a pressure control system, an air inlet, a furnace body, a collection tank and a tail gas treatment device; The liquid sample feeding system, the atomization chamber, the furnace body, the collection tank and the tail gas treatment device are sequentially connected by pipelines; the air inlet is communicated with the atomization chamber; The pressure control system is arranged outside the atomization chamber and is used for pressurizing the carrier gas entering the atomization chamber through the air inlet; The pipeline end of the atomization chamber communicated with the furnace body is connected with a horn; The preparation process comprises the following steps: The temperature in the furnace body is set to 800-1300℃, the carrier gas is introduced into the carbon nanotube preparation system through the air inlet, the reaction raw material is added into the liquid sample feeding system and is atomized through the atomization chamber, and then enters the furnace body through the horn; The reaction product is collected by the collection tank, and the tail gas is treated by the tail gas treatment device; During the preparation process, the pressure control system is used to control the pressure of the atomization chamber to be 10-100atm; The pipeline between the discharge port of the furnace body and the collection tank is improved, and a long temperature buffer area is arranged at the outlet of the furnace tube, so that the generated single-walled carbon nanotube product is collected under the condition that the temperature gradually decreases, so as to reduce the possibility of adhesion to the inner wall of the metal tube; The reaction raw material is a mixed solution of liquid carbon source, iron salt and sulfur source; the carrier gas is a mixed gas with a volume ratio of hydrogen to nitrogen of 2:1; The liquid carbon source comprises ethanol, toluene or cyclohexane; the iron salt comprises one or more of ferric chloride, ferrous chloride, ferric acetate, ferric nitrate and ferrocene; The sulfur source comprises thiophene, ethyl mercaptan, ethyl sulfide or sulfide.

2. The single-walled carbon nanotube production process of claim 1, wherein, The carbon nanotube continuous preparation system takes the carbon nanotube preparation system as a repeating unit, and the tail gas treatment device of the previous repeating unit is communicated with the air inlet of the next repeating unit; the tail gas treated by the tail gas treatment device enters the air inlet of the next repeating unit to continuously prepare carbon nanotubes.

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