A device and method for continuously preparing and collecting sponge-like single-walled carbon nanotubes by floating catalyst chemical vapor deposition method

Abstract

The present invention relates to a technology for preparing and continuously collecting sponge-like single-walled carbon nanotubes, specifically a device and method for continuously preparing and collecting sponge-like single-walled carbon nanotubes by a floating catalyst chemical vapor deposition method. The device comprises a micro-injection pump for supplying a catalyst and a liquid carbon source, a floating catalyst chemical vapor deposition reaction chamber, and a continuous collection and transfer device, and the specific structure is as follows: the floating catalyst chemical vapor deposition reaction chamber is horizontally arranged in the cavity of a tubular furnace, a syringe is installed on the micro-injection pump to form a catalyst injection device, the micro-injection pump corresponds to the center hole at the head end of the floating catalyst chemical vapor deposition reaction chamber through the syringe, and the cross-cylindrical channel of the continuous collection and transfer device is connected to the tail end of the floating catalyst chemical vapor deposition reaction chamber. The present invention overcomes the problem that the current floating catalyst chemical vapor deposition method for growing sponge-like single-walled carbon nanotubes cannot achieve continuous collection, and breaks through the technical bottleneck in this aspect of the field.

Description

Technical Field

[0001] The invention relates to a preparation and continuous collection technology of sponge-like single-walled carbon nanotubes, in particular to a device and method for continuously preparing and collecting sponge-like single-walled carbon nanotubes by a floating catalyst chemical vapor deposition method. Background Art

[0002] Carbon nanotubes have excellent physical and chemical properties such as low density, high conductivity, high mechanical strength, and high stability. They can be used in many fields such as optoelectronic devices, energy storage devices, lightweight wires, flexible transparent conductive films, composite materials, and conductive additives. Methods for preparing carbon nanotubes include arc discharge, laser evaporation and chemical vapor deposition, and the resulting product morphologies include powders, arrays, films, etc. (Reference 1, Kong J, et al. Synthesis of individualsingle-walled carbon nanotubes on patterned silicon wafers. Nature, 1998, 395 (6705): 878; Reference 2, Yu H, et al. Agglomerated CNTs synthesized in a fluidized bed reactor: Agglomerate structure and formation mechanism. Carbon, 2003, 41 (14): 2855; Reference 3, Journet C, et al. Large-scale production of single-walled carbon nanotubes by the electric-arc technique. Nature, 1997, 388 (6644): 756; Reference 4, Guo T, et al. Self-assembly of tubular fullerenes. Journal of Physical Chemistry, 1995, 99(27): 10694.). The floating catalyst chemical vapor deposition method for preparing carbon nanotubes has the advantages of high purity, continuity, and easy scale-up. However, this method is currently mostly used to prepare single-walled / few-walled carbon nanotube films or fiber products (CN104261384B, CN114808196A, CN114974726A), and there is still a lack of key technologies and equipment for the continuous preparation of sponge-like single-walled carbon nanotubes by floating catalyst chemical vapor deposition.

[0003] Mass production of carbon nanotubes is an important step towards their practical application. Sponge-like carbon nanotubes, as a three-dimensional structure formed by stacking, are a form of macroscopic carbon nanotubes. They have the characteristics of low density and rich pore structure; therefore, in conventional floating catalytic chemical vapor deposition reaction chambers, limited by the volume and airtightness of the reaction chamber, sponge-like carbon nanotubes cannot achieve long-term continuous growth. The main reason is that sponge-like carbon nanotubes will be retained and blocked in the reaction chamber, causing the pressure of the reaction chamber to increase, making it impossible to prepare continuously for a long time.

[0004] Therefore, establishing a device for continuously collecting and transferring sponge-like single-walled carbon nanotubes has very important basic research significance and practical application value. Summary of the invention

[0005] The purpose of the present invention is to provide a device and method for continuously preparing and collecting sponge-like single-walled carbon nanotubes by floating catalyst chemical vapor deposition, so as to solve the problem of discontinuity in preparing sponge-like single-walled carbon nanotubes by floating catalyst chemical vapor deposition and break through the technical bottleneck in this field.

[0006] The technical solution of the present invention is:

[0007] A device for continuously preparing and collecting sponge-like single-walled carbon nanotubes by a floating catalyst chemical vapor deposition method, the device comprises a micro-injection pump for supplying a catalyst and a liquid carbon source, a floating catalyst chemical vapor deposition reaction chamber, and a continuous collection and transfer device, and the specific structure is as follows: the floating catalyst chemical vapor deposition reaction chamber is horizontally penetrated in the cavity of a tube furnace, a syringe is installed on the micro-injection pump to form a catalyst injection device, the micro-injection pump corresponds to the center hole at the head end of the floating catalyst chemical vapor deposition reaction chamber through the syringe, and the cross-cylindrical channel of the continuous collection and transfer device is connected to the tail end of the floating catalyst chemical vapor deposition reaction chamber.

[0008] The floating catalyst chemical vapor deposition method is used to continuously prepare and collect the sponge-like single-walled carbon nanotubes. The floating catalyst chemical vapor deposition reaction chamber is a stainless steel tube, a corundum tube or a quartz tube, and water cooling sleeves are installed at both ends to seal it.

[0009] The floating catalyst chemical vapor deposition method is used to continuously prepare and collect the sponge-like single-walled carbon nanotubes. The continuous collection and transfer device includes a product extraction chamber, a hook-shaped push-pull rod, a rectangular push-pull rod, a circular push-pull rod, and a cross-cylindrical channel. The specific structure is as follows:

[0010] The cross-cylindrical channel is a cross-connected structure in which the first cylindrical channel and the second cylindrical channel are connected in a cross shape. The cross-cylindrical channel is connected to the tail end of the floating catalyst chemical vapor deposition reaction chamber through a port of the first cylindrical channel. The first cylindrical channel is coaxial with the floating catalyst chemical vapor deposition reaction chamber, and an observation window is provided at the other port of the first cylindrical channel; the cross-cylindrical channel is connected to the product extraction chamber through a port of the second cylindrical channel. The second cylindrical channel is coaxial with the product extraction chamber, and a gate valve is installed at the connection between the second cylindrical channel and the product extraction chamber to separate the product extraction chamber from the floating catalyst chemical vapor deposition reaction chamber. A circular push-pull rod is provided at the other end of the cylindrical channel, the product extraction chamber, the circular push-pull rod and the floating catalyst chemical vapor deposition reaction chamber are arranged in a vertical direction, the circular push-pull rod is coaxial with the product extraction chamber, one end of the circular push-pull rod passes through the second cylindrical channel and corresponds to the product extraction chamber; the hook-shaped push-pull rod is arranged axially along the first cylindrical channel and the floating catalyst chemical vapor deposition reaction chamber, one end of the hook-shaped push-pull rod passes through the first cylindrical channel and corresponds to the tail end of the floating catalyst chemical vapor deposition reaction chamber; the vertical rectangular push-pull rod is located above the front of the product extraction chamber and remains perpendicular to the product extraction chamber, and the lower end of the rectangular push-pull rod extends into the product extraction chamber.

[0011] The floating catalyst chemical vapor deposition method is used to continuously prepare and collect sponge-like single-walled carbon nanotubes. The bottom of the cross-cylindrical channel is connected to the exhaust port through a pipeline. The front side of the product extraction chamber is provided with a product extraction chamber exhaust port and a product extraction chamber air outlet. The other side of the front of the product extraction chamber is provided with an air inlet, and a pressure gauge is installed above the front of the product extraction chamber.

[0012] A method for continuously preparing and collecting sponge-like single-walled carbon nanotubes by a floating catalyst chemical vapor deposition method. A sponge-like single-walled carbon nanotube continuous collection and transfer device is designed and installed at the tail end of a floating catalyst chemical vapor deposition reaction chamber. The continuous collection and transfer device is linked by a push-pull rod and a gate valve to transfer the sponge-like single-walled carbon nanotubes accumulated at the rear end of the floating catalyst chemical vapor deposition reaction chamber to a product extraction chamber, thereby realizing controllable collection and transfer of the sponge-like single-walled carbon nanotubes. The product extraction chamber is opened or closed at any time during the single-walled carbon nanotube preparation process, and the extraction and collection of the sponge-like single-walled carbon nanotubes are completed by repeated operations.

[0013] The method for continuously preparing and collecting sponge-like single-walled carbon nanotubes by floating catalyst chemical vapor deposition method uses a hook-shaped push-pull rod to hook the sponge-like single-walled carbon nanotubes out of the floating catalyst chemical vapor deposition reaction chamber, a circular push-pull rod pushes the sponge-like single-walled carbon nanotubes to the product extraction chamber, and a rectangular push-pull rod separates the sponge-like single-walled carbon nanotubes from the circular push-pull rod.

[0014] The method for continuously preparing and collecting sponge-like single-walled carbon nanotubes by floating catalyst chemical vapor deposition is as follows: reactants for floating catalyst chemical vapor deposition are injected into the inner area of ​​the front blind plate of the floating catalyst chemical vapor deposition reaction chamber, and the single-walled carbon nanotubes grow in the constant temperature zone of the floating catalyst chemical vapor deposition reaction chamber and are carried by the airflow to the tail end of the floating catalyst chemical vapor deposition reaction chamber to accumulate and form sponge-like single-walled carbon nanotubes; the tail end of the floating catalyst chemical vapor deposition reaction chamber is connected to a continuous collection and transfer device through a pipeline, and after the sponge-like carbon nanotubes are formed, the hook-shaped push-pull rod on the continuous collection and transfer device passes through the first cylindrical channel of the cross cylindrical channel and extends to the floating catalyst The tail end of the catalyst chemical vapor deposition reaction chamber is used to pull the sponge-like carbon nanotubes to the cross-cylindrical channel connecting the product extraction chamber and the floating catalyst chemical vapor deposition reaction chamber; at the same time, after the product extraction chamber is evacuated, the carbon nanotube growth reaction gas is introduced into the product extraction chamber, the gate valve is opened, and the circular push-pull rod is used to push the sponge-like carbon nanotubes into the front part of the product extraction chamber, and then the sponge-like carbon nanotubes are separated from the circular push-pull rod by operating the rectangular push-pull rod; then, after restoring the push-pull rods at various locations to their initial positions, the gate valve is closed; after nitrogen or argon is introduced into the product extraction chamber through the air inlet to evacuate the carbon nanotube growth reaction gas, the product extraction chamber is opened, and the sponge-like carbon nanotubes are taken out.

[0015] The method for continuously preparing and collecting sponge-like single-walled carbon nanotubes by floating catalyst chemical vapor deposition comprises the following steps: before performing the sponge-like carbon nanotube extraction operation, firstly closing the gate valve between the product extraction chamber and the floating catalyst chemical vapor deposition reaction chamber, introducing nitrogen or argon into the product extraction chamber through the air inlet to evacuate the carbon nanotube growth reaction gas in the chamber; then stopping the introduction of nitrogen or argon, opening the product extraction chamber, and collecting and transferring the product; then evacuating the product extraction chamber, introducing the carbon nanotube growth reaction gas; and then opening the gate valve between the product extraction chamber and the floating catalyst chemical vapor deposition reaction chamber.

[0016] The design concept of the present invention is:

[0017] Based on the current situation that the sponge-like single-walled carbon nanotubes grown by the floating catalyst chemical vapor deposition method usually adhere to the low-temperature zone of the floating catalyst chemical vapor deposition reaction chamber, causing the furnace tube to be blocked, the pressure in the furnace to increase and continuous production cannot be achieved, the present invention designs and installs a sponge-like single-walled carbon nanotube continuous collection and transfer device at the tail end of the floating catalyst chemical vapor deposition reaction chamber, and transfers the sponge-like single-walled carbon nanotubes accumulated at the rear end of the floating catalyst chemical vapor deposition reaction chamber to the product extraction chamber through the linkage of a push-pull rod and a gate valve, thereby realizing the room temperature, normal pressure, multiple transfer and collection of the sponge-like single-walled carbon nanotubes, and solving the technical problem that the floating catalyst chemical vapor deposition method is difficult to mass produce.

[0018] The continuous collection and transfer device is connected to the tail end of the floating catalyst chemical vapor deposition reaction chamber. The equipped product extraction chamber can be opened or closed at any time during the single-walled carbon nanotube preparation process, and can be repeated multiple times to complete the product extraction and collection operation. During this operation, the operation of the floating catalyst chemical vapor deposition preparation system is not affected.

[0019] The top shapes of the push-pull rods on the cross-cylindrical channel are hook-shaped, circular, and rectangular. The hook-shaped push-pull rod can be used to hook the product out of the floating catalyst chemical vapor deposition reaction chamber, the circular push-pull rod can push the product to the product extraction chamber, and the rectangular push-pull rod can separate the product from the circular push-pull rod. The collected sponge-like single-walled carbon nanotubes have the characteristics of high G / D ratio, low catalyst content, high anti-oxidation temperature and low density, which greatly improves the production efficiency of single-walled carbon nanotubes (5 to 15 times / day) and reduces energy consumption and costs.

[0020] The advantages and beneficial effects of the present invention are:

[0021] 1. The present invention is the first to install a continuous collection and transfer device for sponge-like single-walled carbon nanotubes at the tail end of the floating catalyst chemical vapor deposition reaction chamber. One side of the product extraction chamber can be separated from the floating catalyst chemical vapor deposition reaction chamber, so that multiple collections of the product can be achieved, which overcomes the problem that the current floating catalyst chemical vapor deposition method cannot continuously prepare sponge-like single-walled carbon nanotubes, and breaks through the technical bottleneck in this area of ​​the field.

[0022] 2. The present invention realizes multiple extractions during the growth of single-walled carbon nanotubes, avoiding the problem of clogging and termination of growth due to excessive pressure caused by product retention in the floating catalyst chemical vapor deposition reaction chamber.

[0023] 3. The equipment of the present invention is simple, easy to scale up, and suitable for industrial mass production. It solves the key technical problems of mass production of sponge-like single-walled carbon nanotubes and has good application prospects.

[0024] 4. The present invention greatly improves the production efficiency of single-walled carbon nanotubes and effectively reduces energy consumption and costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 .Front view of the schematic diagram of the device for continuously preparing and collecting sponge-like single-walled carbon nanotubes using the floating catalyst chemical vapor deposition method.

[0026] Figure 2 .Side view of the schematic diagram of the device for continuously preparing and collecting sponge-like single-walled carbon nanotubes using floating catalyst chemical vapor deposition.

[0027] Figure 1-Figure 2Among them, 1. tubular furnace, 2. floating catalyst chemical vapor deposition reaction chamber, 3. continuous collection and transfer device, 4. gate valve, 5. pressure gauge, 6. product extraction chamber exhaust port, 7. hook-type push-pull rod, 8. air inlet, 9. product extraction chamber, 10. exhaust port, 11. rectangular push-pull rod, 12. circular push-pull rod, 13. product extraction chamber outlet, 14. observation window, 15. micro-injection pump, 16. syringe, 17. cross cylindrical channel, 18. first cylindrical channel, 19. second cylindrical channel.

[0028] Figure 3 .Optical photograph of the prepared sponge-like carbon nanotubes.

[0029] Figure 4 .Scanning electron microscope photograph of the prepared sponge-like carbon nanotubes.

[0030] Figure 5 .Transmission electron microscope photograph of the prepared sponge-like carbon nanotubes.

[0031] Figure 6 .Laser Raman spectrum of the prepared sponge-like carbon nanotubes. In the figure, the horizontal axis Raman Shift represents the Raman shift (cm -1 ), the ordinate Intensity represents the Raman peak intensity (au).

[0032] Figure 7 .Thermogravimetric / exothermic curve of the prepared sponge-like carbon nanotubes. In the figure, the horizontal axis Temperature represents the temperature (°C), the vertical axis TG on the right represents the weight loss rate (%), and the vertical axis ΔT on the left represents the temperature difference (μV / mg).

[0033] Figure 8 . Schematic diagram of the equipment without continuous collection device installed.

[0034] Fig. 9 .Photo of sponge-like carbon nanotubes retained in the reaction chamber when no continuous collection device is installed. DETAILED DESCRIPTION

[0035] like Figure 1-Figure 2 As shown, the present invention proposes a device for continuously preparing and collecting sponge-like single-walled carbon nanotubes by floating catalyst chemical vapor deposition method, which mainly includes: a micro-injection pump 15 for supplying catalyst and liquid carbon source, a floating catalyst chemical vapor deposition reaction chamber 2, a continuous collection and transfer device 3, etc. The specific structure is as follows:

[0036] The floating catalyst chemical vapor deposition reaction chamber 2 is horizontally arranged in the cavity of the tube furnace 1, the micro-injection pump 15 corresponds to the center hole of the head end of the floating catalyst chemical vapor deposition reaction chamber 2 through the syringe 16, and the cross cylindrical channel 17 of the continuous collection and transfer device 3 is connected to the tail end of the floating catalyst chemical vapor deposition reaction chamber 2. The floating catalyst chemical vapor deposition reaction chamber 2 can be a stainless steel tube, a corundum tube or a quartz tube, etc., and water cooling jackets are installed at both ends to seal.

[0037] like Figure 1-Figure 2 As shown, the continuous collection and transfer device 3 is mainly composed of a product extraction chamber 9, a hook-shaped push-pull rod 7, a rectangular push-pull rod 11, a circular push-pull rod 12, and a cross cylindrical channel 17. The specific structure is as follows:

[0038] The cross cylindrical channel 17 is a cross-connected structure in which the first cylindrical channel 18 and the second cylindrical channel 19 are connected in a cross shape. The cross cylindrical channel 17 is connected to the tail end of the floating catalyst chemical vapor deposition reaction chamber 2 through one end of the first cylindrical channel 18. The first cylindrical channel 18 is coaxial with the floating catalyst chemical vapor deposition reaction chamber 2. An observation window 14 is provided at the other end of the first cylindrical channel 18. The cross cylindrical channel 17 is connected to the product extraction chamber 9 through one end of the second cylindrical channel 19. The second cylindrical channel 19 is connected to the product extraction chamber 9 through one end of the second cylindrical channel 19. The channel 19 is coaxial with the product extraction chamber 9. A gate valve 4 is installed at the connection between the second cylindrical channel 19 and the product extraction chamber 9 to separate the product extraction chamber 9 from the floating catalyst chemical vapor deposition reaction chamber 2. A circular push-pull rod 12 is provided at the other end of the second cylindrical channel 19. The product extraction chamber 9, the circular push-pull rod 12 and the floating catalyst chemical vapor deposition reaction chamber 2 are arranged in a vertical direction. The circular push-pull rod 12 is coaxial with the product extraction chamber 9. One end of the circular push-pull rod 12 passes through the second cylindrical channel 19 and corresponds to the product extraction chamber 9. The hook-type push-pull rod 7 is arranged along the axial direction of the first cylindrical channel 18 and the floating catalyst chemical vapor deposition reaction chamber 2. One end of the hook-type push-pull rod 7 passes through the first cylindrical channel 18 and corresponds to the tail end of the floating catalyst chemical vapor deposition reaction chamber 2. The vertical rectangular push-pull rod 11 is located above the front of the product extraction chamber 9 and remains vertical to the product extraction chamber 9. The lower end of the rectangular push-pull rod 11 extends into the product extraction chamber 9.

[0039] The bottom of the cross cylindrical channel 17 is connected to the exhaust port 10 through a pipeline, and the floating catalyst chemical vapor deposition reaction chamber 2 is evacuated through the exhaust port 10. A product extraction chamber exhaust port 6 and a product extraction chamber gas outlet 13 are provided on one side of the front of the product extraction chamber 9, and the product extraction chamber 9 is evacuated through the product extraction chamber exhaust port 6. The other side of the front of the product extraction chamber 9 is provided with an air inlet 8, and nitrogen or argon is introduced into the product extraction chamber 9 through the air inlet 8, and the carbon nanotube growth reaction gas in the product extraction chamber 9 is emptied through the product extraction chamber gas outlet 13. A pressure gauge 5 is installed above the front of the product extraction chamber 9 to measure the air pressure in the product extraction chamber 9.

[0040] A syringe 16 is installed on the micro-injection pump 15 to form a catalyst injection device, and the reactant is injected into the inner area of ​​the front blind plate of the floating catalyst chemical vapor deposition reaction chamber 2 at 0.5-5 ml / h, and the temperature is about 100-280° C. The single-walled carbon nanotubes grow in the constant temperature zone of the floating catalyst chemical vapor deposition reaction chamber 2, and are carried by the airflow to the tail end of the floating catalyst chemical vapor deposition reaction chamber 2, and accumulate to form sponge-like single-walled carbon nanotubes. The tail end of the floating catalyst chemical vapor deposition reaction chamber 2 is connected to the continuous collection and transfer device 3 through a stainless steel pipe. After the sponge-like carbon nanotubes are formed, the hook-shaped push-pull rod 7 on the continuous collection and transfer device 3 passes through the first cylindrical channel 18 of the cross-cylindrical channel 17 and extends to the tail end of the floating catalyst chemical vapor deposition reaction chamber 2 to pull the sponge-like carbon nanotubes to the cross-cylindrical channel 17 where the product extraction chamber 9 and the floating catalyst chemical vapor deposition reaction chamber 2 are connected; at the same time, after the product extraction chamber 9 is evacuated, the carbon nanotube growth reaction gas is introduced into the product extraction chamber 9, and its function is: when the gate valve 4 between the product extraction chamber 9 and the floating catalyst chemical vapor deposition reaction chamber 2 is opened, no other gas that can affect the single-walled carbon nanotube growth experiment in the floating catalyst chemical vapor deposition reaction chamber 2 is introduced, and the introduction of oxygen is particularly prohibited to avoid the danger of hydrogen flash explosion. Open the gate valve 4, use the circular push-pull rod 12 to push the sponge-like carbon nanotubes into the front of the product extraction chamber 9, and then separate the sponge-like carbon nanotubes from the circular push-pull rod 12 by operating the rectangular push-pull rod 11; then, after returning the push-pull rods to their initial positions, close the gate valve 4. After nitrogen or argon is introduced into the product extraction chamber 9 through the air inlet 8 to evacuate the carbon nanotube growth reaction gas, open the product extraction chamber 9 and take out the sponge-like carbon nanotubes. The observation window 14 on the continuous collection and transfer device and the observation window at the opening of the product extraction chamber 9 are helpful for observing the specific position of the sponge-like carbon nanotubes when operating the push-pull rods. The above-mentioned operation of extracting sponge-like carbon nanotubes can be repeated many times to achieve the purpose of continuous preparation and collection.

[0041] Below, the present invention is further described in detail by examples.

[0042] Example

[0043] like Figure 1 As shown, the catalyst precursor (ferrocene), growth promoter (thiophene), and toluene are mixed evenly in a weight ratio of 2:1:10 and placed in a catalyst injection device. Under the condition of an atmosphere with a hydrogen flow rate of 200sccm, the floating catalyst chemical vapor deposition reaction chamber is heated to 1100°C, and then the hydrogen flow rate is increased to 4500sccm. At the same time, ethylene with a flow rate of 10sccm is introduced, and the micro-injection pump is turned on to inject the toluene solution containing the catalyst precursor and the growth promoter into the floating catalyst chemical vapor deposition reaction chamber at an injection rate of 0.9ml / h. The toluene solution containing the catalyst precursor and the growth promoter is vaporized at the injection end of the syringe, and flows to the constant temperature reaction zone with the air flow to start growing single-walled carbon nanotubes. The grown single-walled carbon nanotubes flow to the tail end of the reaction chamber with the air flow to form a sponge-like macroscopic body. After about 1 hour of growth, the product extraction chamber is evacuated and the carbon nanotube growth reaction gas is introduced to normal pressure; the gate valve between the product extraction chamber and the floating catalyst chemical vapor deposition reaction chamber is opened, and the sponge-like carbon nanotubes are pushed into the product extraction chamber by operating the push-pull rods at different positions. The gate valve is closed, nitrogen or argon is introduced into the product extraction chamber, the carbon nanotube growth reaction gas is emptied, the nitrogen or argon is stopped, the product extraction chamber is opened, and the sponge-like carbon nanotubes are taken out. During this series of operations, the growth reaction of the carbon nanotubes in the floating catalyst chemical vapor deposition reaction chamber is not affected and continues. The product extraction chamber is restored to the initial state, and the above operation is repeated after 1 hour to achieve the purpose of continuously collecting and transferring the sponge-like carbon nanotubes.

[0044] like Figure 3 As shown in the figure, the sponge-like carbon nanotubes prepared after 5 consecutive collections are aggregates of multiple cylinders, with a macroscopic length of 5 to 30 cm and a diameter of about 5 to 6 cm. Figure 4 As shown in the figure, the scanning electron microscope observation shows that it is pure carbon nanotubes with uniform diameter. Figure 5 As shown in Figure 2, observation under a transmission electron microscope shows that the walls of single-walled carbon nanotubes are straight and aggregated into bundles with a diameter of about 20 nm. Figure 6 As shown in the Raman spectrum curve, it can be seen that the high G / D peak ratio indicates that the obtained single-walled carbon nanotubes have fewer defects and higher quality. Figure 7As shown in the figure, the typical thermogravimetric / exothermic curve of the prepared sponge-like single-walled carbon nanotube sample shows that the sample has almost no weight loss below 530°C, indicating that the content of impurities such as amorphous carbon is very low; in the temperature range of 650-830°C, the sample loses weight rapidly, corresponding to the oxidation of single-walled carbon nanotubes, and the DSC curve shows an obvious exothermic peak at around 733°C, indicating that the sponge-like single-walled carbon nanotube sample has high crystallinity and structural uniformity, which is consistent with the results of transmission electron microscopy and Raman characterization. In addition, the catalyst residue of the sponge-like single-walled carbon nanotube sample is 2.26wt%, which proves the high purity of the sample, which is consistent with the characterization results of scanning electron microscopy.

[0045] Comparative Example

[0046] like Figure 8 As shown, a schematic diagram of a floating catalyst chemical vapor deposition device for growing sponge-like single-walled carbon nanotubes without the continuous collection and transfer device 3 is shown. The catalyst precursor (ferrocene), the growth promoter (thiophene), and toluene are mixed evenly in a weight ratio of 2:1:10 and placed in a catalyst injection device. Under an atmosphere with a hydrogen flow rate of 200sccm, the floating catalyst chemical vapor deposition reaction chamber is heated to 1100°C, and then the hydrogen flow rate is increased to 4500sccm. At the same time, ethylene with a flow rate of 10sccm is introduced, and the micro-injection pump is turned on to inject a toluene solution containing the catalyst and the growth promoter into the reaction chamber at an injection rate of 0.9ml / h. The toluene solution containing the catalyst and the growth promoter is vaporized at the injection end of the syringe, and flows to the constant temperature reaction zone with the air flow to start growing single-walled carbon nanotubes. The grown single-walled carbon nanotubes flow to the tail end of the reaction chamber with the air flow to form a sponge-like macroscopic body. After about 1.2 hours of growth, the pressure in the device rose to 105KPa, indicating that the sponge-like single-walled carbon nanotubes at the tail end of the furnace tube had blocked the tail end of the furnace tube. For safety reasons, the supply of hydrogen and gaseous carbon source was immediately stopped, the injection pump was stopped, the power switch was turned off, and the furnace tube was cooled to room temperature under the protection of a small amount of argon. After opening the tail valve and collecting the sample, it can be seen that the cylindrical sponge carbon nanotube sample has accumulated at the tail end of the floating catalyst chemical vapor deposition reaction chamber ( Fig. 9 ).

[0047] The results of the embodiments and comparative examples show that the technology of continuously collecting and transferring sponge-like single-walled carbon nanotubes by the floating catalyst chemical vapor deposition method proposed in the present invention solves the problem of terminating the growth experiment due to excessive pressure in the reaction chamber caused by product retention and accumulation in the floating catalyst chemical vapor deposition reaction chamber, realizes the collection and transfer of single-walled carbon nanotubes during the growth process, greatly improves the production efficiency of single-walled carbon nanotubes, reduces energy consumption and costs, and promotes the mass production of high-quality sponge-like single-walled carbon nanotubes.

[0048] The above specifically describes the design concept and implementation scheme of the present invention, but some modifications and improvements can still be made on the basis of the present invention. These modifications or improvements made on the basis of not departing from the spirit of the present invention all belong to the scope of protection claimed by the present invention.

Claims

1. A device for continuously preparing and collecting sponge-like single-walled carbon nanotubes by floating catalyst chemical vapor deposition, characterized in that: The device comprises a micro-injection pump for supplying catalyst and liquid carbon source, a floating catalyst chemical vapor deposition reaction chamber, and a continuous collection and transfer device, and the specific structure is as follows: the floating catalyst chemical vapor deposition reaction chamber is horizontally arranged in the cavity of the tube furnace, a syringe is installed on the micro-injection pump to form a catalyst injection device, the micro-injection pump corresponds to the center hole at the head end of the floating catalyst chemical vapor deposition reaction chamber through the syringe, and the cross cylindrical channel of the continuous collection and transfer device is connected to the tail end of the floating catalyst chemical vapor deposition reaction chamber; The continuous collection and transfer device includes a product extraction chamber, a hook-shaped push-pull rod, a rectangular push-pull rod, a circular push-pull rod, and a cross cylindrical channel. The specific structure is as follows: The cross-cylindrical channel is a cross-connected structure in which the first cylindrical channel and the second cylindrical channel are connected in a cross shape. The cross-cylindrical channel is connected to the tail end of the floating catalyst chemical vapor deposition reaction chamber through a port of the first cylindrical channel. The first cylindrical channel is coaxial with the floating catalyst chemical vapor deposition reaction chamber, and an observation window is provided at the other port of the first cylindrical channel; the cross-cylindrical channel is connected to the product extraction chamber through a port of the second cylindrical channel. The second cylindrical channel is coaxial with the product extraction chamber, and a gate valve is installed at the connection between the second cylindrical channel and the product extraction chamber to separate the product extraction chamber from the floating catalyst chemical vapor deposition reaction chamber. A circular push-pull rod is provided at the other end of the cylindrical channel, the product extraction chamber, the circular push-pull rod and the floating catalyst chemical vapor deposition reaction chamber are arranged in a vertical direction, the circular push-pull rod is coaxial with the product extraction chamber, one end of the circular push-pull rod passes through the second cylindrical channel and corresponds to the product extraction chamber; the hook-shaped push-pull rod is arranged axially along the first cylindrical channel and the floating catalyst chemical vapor deposition reaction chamber, one end of the hook-shaped push-pull rod passes through the first cylindrical channel and corresponds to the tail end of the floating catalyst chemical vapor deposition reaction chamber; the vertical rectangular push-pull rod is located above the front of the product extraction chamber and remains perpendicular to the product extraction chamber, and the lower end of the rectangular push-pull rod extends into the product extraction chamber.

2. The device for continuously preparing and collecting sponge-like single-walled carbon nanotubes by floating catalyst chemical vapor deposition method according to claim 1, characterized in that: The floating catalyst chemical vapor deposition reaction chamber is a stainless steel tube, a corundum tube or a quartz tube, and water cooling jackets are installed at both ends to seal.

3. The device for continuously preparing and collecting sponge-like single-walled carbon nanotubes by floating catalyst chemical vapor deposition method according to claim 1, characterized in that: The bottom of the cross cylindrical channel is connected to the vacuum port through a pipeline, a product extraction chamber vacuum port and a product extraction chamber air outlet are provided on one side of the front of the product extraction chamber, an air inlet is provided on the other side of the front of the product extraction chamber, and a pressure gauge is installed above the front of the product extraction chamber.

4. A method for continuously preparing and collecting sponge-like single-walled carbon nanotubes by a floating catalyst chemical vapor deposition method using the device according to any one of claims 1 to 3, characterized in that: A sponge-like single-walled carbon nanotube continuous collection and transfer device is designed and installed at the rear end of a floating catalyst chemical vapor deposition reaction chamber. The continuous collection and transfer device is linked by a push-pull rod and a gate valve to transfer the sponge-like single-walled carbon nanotubes accumulated at the rear end of the floating catalyst chemical vapor deposition reaction chamber to a product extraction chamber, thereby realizing controllable collection and transfer of the sponge-like single-walled carbon nanotubes. The product extraction chamber can be opened or closed at any time during the preparation process of the single-walled carbon nanotubes, and the extraction and collection of the sponge-like single-walled carbon nanotubes can be completed through repeated operations.

5. The method for continuously preparing and collecting sponge-like single-walled carbon nanotubes by floating catalyst chemical vapor deposition method according to claim 4, characterized in that: The hook-shaped push-pull rod is used to hook the sponge-like single-walled carbon nanotubes out of the floating catalyst chemical vapor deposition reaction chamber, the circular push-pull rod pushes the sponge-like single-walled carbon nanotubes to the product extraction chamber, and the rectangular push-pull rod separates the sponge-like single-walled carbon nanotubes from the circular push-pull rod.

6. The method for continuously preparing and collecting sponge-like single-walled carbon nanotubes by floating catalyst chemical vapor deposition according to claim 4, characterized in that: The reactants for floating catalyst chemical vapor deposition are injected into the inner area of ​​the front blind plate of the floating catalyst chemical vapor deposition reaction chamber, and the single-walled carbon nanotubes grow in the constant temperature zone of the floating catalyst chemical vapor deposition reaction chamber and are carried by the airflow to the tail end of the floating catalyst chemical vapor deposition reaction chamber to accumulate and form sponge-like single-walled carbon nanotubes; the tail end of the floating catalyst chemical vapor deposition reaction chamber is connected to a continuous collection and transfer device through a pipeline, and after the sponge-like carbon nanotubes are formed, the hook-shaped push-pull rod on the continuous collection and transfer device passes through the first cylindrical channel of the cross cylindrical channel to the tail end of the floating catalyst chemical vapor deposition reaction chamber, and the sea The sponge-like carbon nanotubes are pulled to the cross-cylindrical channel connecting the product extraction chamber and the floating catalyst chemical vapor deposition reaction chamber; at the same time, after the product extraction chamber is evacuated, the carbon nanotube growth reaction gas is introduced into the product extraction chamber, the gate valve is opened, and the circular push-pull rod is used to push the sponge-like carbon nanotubes into the front of the product extraction chamber, and then the rectangular push-pull rod is operated to separate the sponge-like carbon nanotubes from the circular push-pull rod; then, after restoring the push-pull rods at various locations to their initial positions, the gate valve is closed; after nitrogen or argon is introduced into the product extraction chamber through the air inlet to evacuate the carbon nanotube growth reaction gas, the product extraction chamber is opened, and the sponge-like carbon nanotubes are taken out.

7. The method for continuously preparing and collecting sponge-like single-walled carbon nanotubes by floating catalyst chemical vapor deposition according to claim 6, characterized in that: Before the sponge-like carbon nanotube extraction operation is performed, the gate valve between the product extraction chamber and the floating catalyst chemical vapor deposition reaction chamber is first closed, and nitrogen or argon is introduced into the product extraction chamber through the air inlet to exhaust the carbon nanotube growth reaction gas in the chamber; then the introduction of nitrogen or argon is stopped, the product extraction chamber is opened, and the transferred product is collected; then the product extraction chamber is evacuated and the carbon nanotube growth reaction gas is introduced; Then, the gate valve between the product extraction chamber and the floating catalyst chemical vapor deposition reaction chamber is opened.

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