CN108726506A - Quickly prepare the method and system of ultra-long horizontal carbon nanotube - Google Patents

Abstract

The invention discloses a kind of method and system quickly preparing ultra-long horizontal carbon nanotube.The method includes：An at least catalyst layer is fixed in reative cell, and catalyst layer is made to be connect with heating element heat conduction, carbon-source gas and carrier gas are passed through into reative cell, grows with heating element heats catalyst layer and to form ultra-long horizontal carbon nanotube.The system comprises：Reative cell, the reative cell has an at least air inlet and an at least gas outlet, and an at least catalyst layer is further fixedly arranged in reative cell, and the catalyst layer can be contacted with the reaction gas for flowing to gas outlet from air inlet；Heating element is fixedly installed in reative cell and is connect with catalyst layer heat conduction.The present invention uses carbon material film energization rapid thermal response, and heating rate is fast, and energy consumption cost is low, and catalyst activity is high, and the speed of growth of ultra-long horizontal carbon nanotube is fast, prepared by the magnanimity for being conducive to ultra-long horizontal carbon nanotube.

Description

Method and system for rapidly preparing ultra-long horizontal carbon nanotubes

technical field

The invention relates to a method for rapidly preparing ultra-long horizontal carbon nanotubes, in particular to a method and system for rapidly preparing ultra-long horizontal carbon nanotubes, and belongs to the technical field of nanomaterials.

Background technique

Carbon nanotubes have excellent electrical, optical and mechanical properties, and have always been a research hotspot in the field of nanoscience. They have broad application prospects in many fields such as nanoelectronic devices, energy conversion, biosensing and composite materials. Ultra-long horizontal carbon nanotubes refer to carbon nanotubes with a special shape that grow on a flat substrate surface parallel to the substrate surface and have a length of millimeters or even centimeters or more. This type of carbon nanotubes follows the mechanism of free growth, the distance between the tubes is large, it can get rid of mutual interference, it is easy to reach a length of more than millimeters, and it has a very low defect density, and it is easier to embody carbon nanotubes. theoretically excellent performance. In addition, ultra-long horizontal carbon nanotubes can be directly grown on the surface of silicon wafers, which are compatible with existing semiconductor technologies and can be directly used in the preparation of electronic devices without transfer. They have broad application prospects in the field of nanoelectronic devices and are considered post-Moore Host material in Times Nano electronic devices.

In order to realize the application of ultra-long horizontal carbon nanotubes, it is necessary to realize the batch preparation of ultra-long horizontal carbon nanotubes first, especially to realize the batch preparation of ultra-long carbon nanotubes with a length of meters or even kilometers. At present, the main method for preparing ultra-long horizontal carbon nanotubes is chemical vapor deposition (CVD). It is generally believed that during the growth process of ultra-long horizontal carbon nanotubes, the gas flow orientation is followed, and the catalyst is separated from the substrate and floats in the gas phase. Since the interaction between the catalyst and the substrate is avoided, the carbon nanotubes can grow very long, but the growth rate is very slow. The usual method is only 10 μm/s, which seriously affects the preparation efficiency of ultra-long horizontal carbon nanotubes. Wen et al. (Wen Q, Zhang R F, et al. Chem. Mater., 2010, 22(4): 12194-1296.) greatly promoted the formation of ultra-long horizontal carbon nanotubes by adding a small amount of water to the reaction gas stream. The growth rate reaches 80-90 μm/s, which is the fastest growth rate reported so far. Zhang et al. (Zhang R F, Zhang Y Y, Zhang Q, et al. ACS Nano, 2013, 7:6156–6161.) extended the life of the catalyst by moving the constant temperature zone method, and successfully prepared carbon nanotubes up to half a meter , which is currently the longest carbon nanotube in the world, but the fastest growth rate only reaches 83μm/s. In addition, the growth temperature in the prior art usually exceeds 900°C, and the tube furnace is mainly used for heating, and the heating rate is less than 5°C/s, which takes a long time, resulting in severe aggregation of the catalyst during the heating process and easy deactivation, resulting in a decrease in catalytic efficiency . Furthermore, the existing main growth device is a hot-wall CVD system, which has huge equipment, high requirements for furnace insulation, unstable process, and poor repeatability, which in turn affects batch production.

Therefore, how to increase the growth rate of ultra-long horizontal carbon nanotubes is the key to further increasing the length of carbon nanotubes, and it is also the basis for their future mass production.

Contents of the invention

The main purpose of the present invention is to provide a method and system for rapidly preparing ultra-long horizontal carbon nanotubes, so as to overcome the deficiencies in the prior art.

In order to realize the aforementioned object of the invention, the technical solutions adopted in the present invention include:

The embodiment of the present invention provides a method for rapidly preparing ultra-long horizontal carbon nanotubes, which includes:

fixing at least one catalyst layer in the reaction chamber, and connecting the catalyst layer to the heating element in thermal connection;

Introduce carbon source gas and carrier gas into the reaction chamber;

The catalyst layer is heated by a heating element to grow and form ultra-long horizontal carbon nanotubes.

In some typical implementation cases, the heating element uses a carbon material film.

In some exemplary implementations, the method includes:

placing the catalyst layer in the reaction chamber, and connecting the catalyst layer to the carbon material film through heat conduction;

Introduce carbon source gas and carrier gas into the reaction chamber;

The carbon material film heats the catalyst layer by passing an electric current into the carbon material film to grow and form ultra-long horizontal carbon nanotubes.

The embodiment of the present invention provides a method for rapidly preparing ultra-long horizontal carbon nanotubes, which includes:

Uniformly coating the solution containing the catalyst precursor on the surface of the substrate;

Fixing the substrate with the catalyst precursor loaded on the surface in the reaction chamber, and connecting the substrate with a carbon material film as a heating element for thermal conduction;

Passing protective gas into the reaction chamber, so as to discharge the air in the reaction chamber;

Feed reducing gas, carbon source gas and carrier gas into the reaction chamber, and pass current into the carbon material film to make the carbon material film heat the substrate, so that the catalyst precursor is decomposed and reduced , so as to form a plurality of uniformly dispersed catalyst particles on the surface of the substrate, and simultaneously grow and form ultra-long horizontal carbon nanotubes.

In some exemplary embodiments, the method includes: heating the catalyst particles only with the carbon material film.

The embodiment of the present invention also provides a system for rapidly preparing ultra-long horizontal carbon nanotubes, which includes:

A reaction chamber, the reaction chamber has at least one gas inlet and at least one gas outlet, and at least one catalyst layer is fixedly arranged in the reaction chamber, and the catalyst layer can be in contact with the reaction gas flowing from the gas inlet to the gas outlet ;

The heating element is fixedly arranged in the reaction chamber and is thermally connected with the catalyst layer.

Preferably, the heating element adopts a carbon material film.

Compared with the prior art, the advantages of the present invention include:

1) The method for rapidly preparing ultra-long horizontal carbon nanotubes provided by the present invention adopts the rapid thermal response of carbon film energization, which can rapidly raise the temperature, significantly inhibit the aggregation and deactivation of the catalyst caused by the long-term heating, and significantly improve the catalyst activity. Since the reducing gas and the carbon source gas are introduced into the reaction chamber at the beginning, the formation of the catalyst and the growth of the carbon nanotubes are almost simultaneously completed during the electric heating process of the carbon material film, and there is no need to spend several minutes to several hours like other methods. Ten minutes of catalyst nucleation time, so this method can achieve the rapid growth of ultra-long horizontal carbon nanotubes, up to 960μm/s, at least one order of magnitude higher than the highest value reported in the existing literature, thus realizing the rapid growth of ultra-long horizontal carbon nanotubes preparation;

2) The system for rapidly preparing ultra-long horizontal carbon nanotubes provided by the present invention uses an electric heating device. Compared with the traditional tube furnace, the equipment is simple, the heating speed is fast, the energy consumption cost is low, and it is cold-wall CVD, and the process is stable Good sex. The temperature difference between the heating temperature of the carbon material film and the rest of the reaction chamber exceeds 800°C, which is more conducive to the carbon nanotube catalyst detaching from the substrate surface under the influence of a large temperature difference, maintaining activity for a long time, and realizing rapid ultra-long horizontal carbon nanotube formation. macro preparation;

3) The method of the present invention is not limited to the rapid preparation of ultra-long horizontal carbon nanotubes, and carbon nanotubes of other shapes, such as vertical arrays of carbon nanotubes, agglomerated carbon nanotubes, etc., can also be rapidly prepared.

4) The ultra-long horizontal carbon nanotubes prepared by the method of the present invention can reach a length of 4 mm, and have broad application prospects in the fields of nanoelectronic devices, energy conversion, biosensors, and composite materials.

Description of drawings

Fig. 1 is a schematic flow diagram of the system and method for rapidly preparing ultra-long horizontal carbon nanotubes in a preferred embodiment of the present invention;

Fig. 2a-Fig. 2b are scanning electron micrographs of ultra-long horizontal carbon nanotubes obtained in Example 1 of the present invention;

Fig. 3 is the transmission electron microscope picture of the ultra-long horizontal carbon nanotube obtained in Example 1 of the present invention;

4 is a scanning electron microscope image of the horizontal array of ultralong carbon nanotubes obtained in Example 2 of the present invention;

5 is a scanning electron microscope image of a vertical array of ultra-long horizontal carbon nanotubes obtained in Example 3 of the present invention;

Fig. 6 is a scanning electron micrograph of horizontal carbon nanotubes obtained by using a common tube furnace in Comparative Example 1 of the present invention.

Detailed ways

In view of the deficiencies in the prior art, the inventor of this case was able to propose the technical solution of the present invention after long-term research and extensive practice. The technical solution, its implementation process and principle will be further explained as follows.

An aspect of the embodiments of the present invention provides a method for rapidly preparing ultra-long horizontal carbon nanotubes, which includes:

fixing at least one catalyst layer in the reaction chamber, and connecting the catalyst layer to the heating element in thermal connection;

Introduce carbon source gas and carrier gas into the reaction chamber;

The catalyst layer is heated by a heating element to grow and form ultra-long horizontal carbon nanotubes.

In some typical implementation cases, the heating element uses a carbon material film.

Preferably, the material of the carbon material film includes any one or a combination of two or more of carbon nanotubes, carbon fibers and graphene, but is not limited thereto.

Further, the thickness of the carbon material film is 1-100 μm, especially preferably 5-10 μm, the electrical conductivity is greater than 10 ⁴ S/m, and the strength is greater than 100 MPa.

In some exemplary implementations, the method includes:

placing the catalyst layer in the reaction chamber, and connecting the catalyst layer to the carbon material film through heat conduction;

Introduce carbon source gas and carrier gas into the reaction chamber;

The carbon material film heats the catalyst layer by passing an electric current into the carbon material film to grow and form ultra-long horizontal carbon nanotubes.

Preferably, the intensity of the direct current passing through the carbon material film is 0.1-5A, especially preferably 0.1-0.5A; the time of passing electricity is 1-1000s, especially preferably 1-5s.

In some typical implementation cases, the method specifically includes:

fixing at least one catalyst layer in the reaction chamber, and thermally connecting the catalyst layer to the carbon material film;

Passing protective gas into the reaction chamber, so as to discharge the air in the reaction chamber;

Introduce carbon source gas and carrier gas into the reaction chamber;

The catalyst layer is heated by the carbon material film to grow and form ultra-long horizontal carbon nanotubes.

Preferably, the catalyst layer is placed on the carbon material film, and the carbon material film is also fixedly arranged in the reaction chamber.

Preferably, the method comprises: heating the catalyst layer only with the heating element.

Preferably, during the growth process of ultra-long horizontal carbon nanotubes, the temperature of the catalyst layer is higher than the temperature of other regions in the reaction chamber by more than 800°C.

Preferably, the catalyst layer is supported on the surface of the substrate, and the catalyst layer is thermally connected to the heating element through the substrate.

Further, the substrate with the catalyst layer supported on its surface is placed directly on the carbon material film.

Furthermore, the catalyst layer includes a plurality of catalyst particles uniformly distributed on the surface of the substrate.

Preferably, the size of the catalyst particles is 0.5-5 nm, and the surface density is 10-1000 particles/μm ² . Wherein, if the size of the catalyst particles exceeds 5 nm, no single-walled carbon nanotubes can be obtained, and the areal density of the catalyst particles will also affect the density of the carbon nanotubes.

Preferably, the material of the catalyst particles includes metal nanoparticles and/or inorganic nanoparticles.

Further, the metal nanoparticles include any one or a combination of two or more of Fe, Co, Ni, Cu, Au, Mo, W, Ru, Rh and Pd, preferably Fe nanoparticles, but not limited thereto .

Further, the inorganic nanoparticles include any one or a combination of two or more of SiO ₂ , TiO ₂ and ZnO, but not limited thereto.

Preferably, the base surface is a horizontal plane.

Preferably, the protective gas includes inert gas. Further, the inert gas includes Ar and the like.

Preferably, the carrier gas includes inert gas, further, the inert gas includes Ar or Ar and H ₂ .

Preferably, the carbon source used to form the carbon source gas includes liquid carbon source and/or gaseous carbon source.

Further, the liquid carbon source may be any one or a combination of two or more of carbon-containing compounds such as ethanol, acetone, benzene, and toluene, preferably ethanol, but not limited thereto.

Further, the gaseous carbon source may be any one or a combination of two or more of hydrocarbons such as methane, ethylene and acetylene, preferably acetylene, but not limited thereto.

Preferably, the material of the substrate includes any one or a combination of two or more of SiO ₂ /Si, ST-cut quartz, R-cut quartz, a-plane α-alumina, r-plane α-alumina, and magnesium oxide, preferably SiO ₂ /Si substrate, but not limited thereto.

Another aspect of the embodiments of the present invention provides a method for rapidly preparing ultra-long horizontal carbon nanotubes, which includes:

Uniformly coating the solution containing the catalyst precursor on the surface of the substrate;

Fixing the substrate with the catalyst precursor loaded on the surface in the reaction chamber, and connecting the substrate with a carbon material film as a heating element for thermal conduction;

Passing protective gas into the reaction chamber, so as to discharge the air in the reaction chamber;

Feed reducing gas, carbon source gas and carrier gas into the reaction chamber, and pass current into the carbon material film to make the carbon material film heat the substrate, so that the catalyst precursor is decomposed and reduced , so as to form a plurality of uniformly dispersed catalyst particles on the surface of the substrate, and simultaneously grow and form ultra-long horizontal carbon nanotubes.

Since the reducing gas and the carbon source gas are introduced into the reaction chamber at the beginning, the formation of the catalyst and the growth of the carbon nanotubes are almost simultaneously completed during the electric heating process of the carbon material film, so the method can realize rapid growth.

In some exemplary embodiments, the method includes: heating the catalyst layer only with the carbon material film.

Preferably, during the growth process of ultra-long horizontal carbon nanotubes, the temperature of the catalyst layer is higher than the temperature of other regions in the reaction chamber by more than 800°C.

Further, the substrate is directly placed on the carbon material film.

Preferably, the base surface is a horizontal plane.

Preferably, the material of the carbon material film includes any one or a combination of two or more of carbon nanotubes, carbon fibers and graphene, but is not limited thereto.

Preferably, the thickness of the carbon material film is 1-100 μm, especially preferably 5-10 μm, the electrical conductivity is greater than 10 ⁴ S/m, and the strength is greater than 100 MPa.

Preferably, the size of the catalyst particles is 0.5-5 nm, and the surface density is 10-1000 particles/μm ² . Wherein, if the size of the catalyst particles exceeds 5 nm, no single-walled carbon nanotubes can be obtained, and the areal density of the catalyst particles will also affect the density of the carbon nanotubes.

Preferably, the material of the catalyst particles includes metal nanoparticles and/or inorganic nanoparticles.

Preferably, the metal nanoparticles include any one or a combination of two or more of Fe, Co, Ni, Cu, Au, Mo, W, Ru, Rh and Pd, preferably Fe nanoparticles, but not limited thereto .

Preferably, the inorganic nanoparticles include any one or a combination of two or more of SiO ₂ , TiO ₂ and ZnO, but not limited thereto.

In some typical embodiments, the fluid containing the catalyst precursor includes Fe(OH) ₃ /EtOH solution.

Further, the concentration of the Fe(OH) ₃ /EtOH solution is 0.01-5 mmol/L, especially preferably 0.05-0.5 mmol/L.

In some typical embodiments, the method includes: coating the solution containing the catalyst precursor on the substrate by a spin coating method. Using the spin coating method, the catalyst particles in the fluid containing the catalyst precursor can be effectively and evenly dispersed on the surface of the substrate, and the density of the catalyst particles on the surface of the substrate can be controlled by using different concentrations of the catalyst and the speed of the homogenizer.

Preferably, the spin coating method includes: placing the clean substrate on a coater, and then applying the fluid containing the catalyst precursor to the surface of the substrate in a dropwise manner.

Preferably, the protective gas includes inert gas. Further, the inert gas includes Ar and the like.

Preferably, the carrier gas includes inert gas, further, the inert gas includes Ar or Ar and H ₂ .

Preferably, the carbon source used to form the carbon source gas includes liquid carbon source and/or gaseous carbon source.

Further, the liquid carbon source may be any one or a combination of two or more of carbon-containing compounds such as ethanol, acetone, benzene, and toluene, preferably ethanol, but not limited thereto.

Further, the gaseous carbon source may be any one or a combination of two or more of hydrocarbons such as methane, ethylene and acetylene, preferably acetylene, but not limited thereto.

Preferably, the material of the substrate includes any one or a combination of two or more of SiO ₂ /Si, ST-cut quartz, R-cut quartz, a-plane α-alumina, r-plane α-alumina, and magnesium oxide, preferably SiO ₂ /Si substrate, but not limited thereto.

In some typical implementation cases, the method includes: first injecting 50-500 sccm of the reducing gas into the reaction chamber for 1-20 min, and then injecting 50-500 sccm of the carbon source gas and carrier gas.

Preferably, the method includes: passing the carbon source gas into the reaction chamber by bubbling a carrier gas.

In some typical implementation cases, the method includes: introducing 50-500 sccm of shielding gas into the reaction chamber for 1-10 minutes, so as to exhaust the air in the reaction chamber.

In some typical implementation cases, the method also includes: after the reaction is finished, stop the power supply and the carbon source gas, keep the reducing gas and the carrier gas to continue to pass, and reduce the temperature of the reaction chamber to room temperature , to obtain ultra-long horizontal carbon nanotubes.

Wherein, in a more specific embodiment, the method for rapidly preparing ultra-long horizontal carbon nanotubes of the present invention may include:

1) Put the clean SiO ₂ /Si substrate on the homogenizer, suck and fix it with a mechanical pump, take 1-20 μL, preferably 1 μL of Fe(OH) ₃ /EtOH solution, drop it on the surface of the substrate, and set up the homogenizer The rotation speed is pre-accelerated to about 500rpm within the first 10 seconds, then increased to 2000rpm, and spin-coated for 1min.

2) Electric heating device connection: see Figure 1, fix the carbon material film (referred to as carbon film) in the quartz tube with copper electrodes, connect the lead wires, lead them out of the tube, and connect them to the DC power supply. The above-mentioned loaded catalyst substrate is placed face up on the carbon material membrane, and the two ends of the tube are connected to the gas circuit.

3) Growth of ultra-long horizontal carbon nanotubes: After the above-mentioned electric heating device is connected to the gas path, first pass into 50～500sccm (preferably 300sccm) Ar exhaust air for 1～10min (preferably 5min), and then pass into 50～500sccm (preferably 100sccm) ) of H ₂ for 1-20 min (preferably 5 min) is used as reducing gas. Then pass into 50～500sccm (preferably 50sccm) of Ar/EtOH (Ar/EtOH refers to passing through ethanol liquid in the form of Ar bubbling) to prepare to start growing carbon nanotubes, and the two ends of the carbon film are loaded with 0.1A～5A (preferably 0.3 A) Current, the power-on time is 1-1000s, then turn off the power supply and stop feeding the carbon source, keep hydrogen and argon gas flowing in, and naturally cool down to room temperature.

The embodiment of the present invention also provides a system for rapidly preparing ultra-long horizontal carbon nanotubes, which includes:

A reaction chamber, the reaction chamber has at least one gas inlet and at least one gas outlet, and at least one catalyst layer is fixedly arranged in the reaction chamber, and the catalyst layer can be in contact with the reaction gas flowing from the gas inlet to the gas outlet ;

The heating element is fixedly arranged in the reaction chamber and is thermally connected with the catalyst layer.

Preferably, the heating element adopts a carbon material film.

Further, the material of the carbon material film includes any one or a combination of two or more of carbon nanotubes, carbon fibers and graphene, but is not limited thereto.

Preferably, the thickness of the carbon material film is 1-100 μm, especially preferably 5-10 μm, the electrical conductivity is greater than 10 ⁴ S/m, and the strength is greater than 100 MPa.

Preferably, the catalyst layer is placed on the carbon material film.

Further, the catalyst layer is supported on the surface of the substrate, and the catalyst layer is thermally connected to the heating element through the substrate.

Furthermore, the substrate with the catalyst layer supported on its surface is placed directly on the carbon material film.

Preferably, the base surface is a horizontal plane.

Preferably, the catalyst layer includes a plurality of catalyst particles uniformly distributed on the surface of the substrate.

Preferably, the size of the catalyst particles is 0.5-5 nm, and the surface density is 10-1000 particles/μm ² . Wherein, if the size of the catalyst particles exceeds 5 nm, no single-walled carbon nanotubes can be obtained, and the areal density of the catalyst particles will also affect the density of the carbon nanotubes.

Preferably, the material of the catalyst particles includes metal nanoparticles and/or inorganic nanoparticles.

Preferably, the metal nanoparticles include any one or a combination of two or more of Fe, Co, Ni, Cu, Au, Mo, W, Ru, Rh and Pd, preferably Fe nanoparticles, but not limited thereto .

Preferably, the inorganic nanoparticles include any one or a combination of two or more of SiO ₂ , TiO ₂ and ZnO, but not limited thereto.

Preferably, the carbon material film is also electrically connected to two or more electrodes arranged at intervals, and the electrodes are electrically connected to a power source.

Further, the material of the electrodes includes copper and the like.

Preferably, the material of the substrate includes any one or a combination of two or more of SiO ₂ /Si, ST-cut quartz, R-cut quartz, a-plane α-alumina, r-plane α-alumina, and magnesium oxide, preferably SiO ₂ /Si substrate, but not limited thereto.

Another aspect of the embodiments of the present invention provides ultra-long horizontal carbon nanotubes prepared by the aforementioned method, the length of the ultra-long horizontal carbon nanotubes can reach more than 4 mm, and the ultra-long horizontal carbon nanotubes have a hollow tubular structure.

Preferably, the ultra-long horizontal carbon nanotubes include single-walled carbon nanotubes, wherein the content of the single-walled carbon nanotubes in the total product exceeds 80wt%.

Another aspect of the embodiments of the present invention also provides the use of the aforementioned ultra-long horizontal carbon nanotubes in the fields of nanoelectronic devices, energy conversion, biosensors or composite materials.

Correspondingly, an embodiment of the present invention also provides a device comprising the aforementioned ultra-long horizontal carbon nanotubes.

Wherein, the device may be a nanoelectronic device, an optoelectronic device, a sensor, or the like.

Utilizing the method for rapidly preparing ultra-long horizontal carbon nanotubes of the present invention can rapidly raise the temperature, the catalyst activity is high, and the growth rate of ultra-long horizontal carbon nanotubes is fast, which can reach 960 μm/s, exceeding the highest value reported in existing literature by at least one order of magnitude. It can realize the rapid macro-preparation of ultra-long horizontal carbon nanotubes.

In addition, by means of the technical solution of the present invention, the obtained ultra-long horizontal carbon nanotubes can reach a length of 4 mm, which has broad application prospects in the fields of nanoelectronic devices, energy conversion, biosensors, and composite materials.

The technical solutions of the present invention will be further described in detail below through several embodiments and in conjunction with the accompanying drawings. However, the selected examples are only for illustrating the present invention and do not limit the scope of the present invention.

Example 1

In this embodiment, the method for rapidly preparing ultra-long horizontal carbon nanotubes on a SiO ₂ /Si substrate includes the following steps:

1) Put the clean SiO ₂ /Si substrate on the homogenizer, suck and fix it with a mechanical pump, take 1 μL of Fe(OH) ₃ /EtOH solution, drop it on the surface of the substrate, set the speed of the homogenizer, and Pre-accelerate to about 500rpm within 10 seconds, then increase the speed to 2000rpm, and spin coat for 1min.

2) Electric heating device connection: see Figure 1, fix a carbon film with a thickness of 10μm, a conductivity of 2×10 ⁴ S/m, and a strength of 200Mpa in the quartz tube with a copper electrode, connect the lead wire, and lead it out of the tube , connected to the DC power supply. Place the above-mentioned loaded catalyst substrate face up on the carbon membrane, and connect the two ends of the tube to the gas circuit.

3) Growth of ultra-long horizontal carbon nanotubes: After the above-mentioned electric heating device is connected to the gas circuit, 300 sccm of Ar exhaust air is introduced for 5 minutes, and then 100 sccm of H ₂ is introduced for 5 minutes as reducing gas. Then feed 50 sccm of Ar/EtOH to prepare to start growing carbon nanotubes, apply 0.3A current to both ends of the carbon film, and the power-on time is 5s. to room temperature to obtain ultra-long horizontal carbon nanotubes.

Further, the inventors of this case also characterized multiple batches of ultra-long horizontal carbon nanotube products prepared by the process described in Example 1, as follows:

Referring to Fig. 2a and Fig. 2b, it is the scanning electron microscope (SEM) picture of the ultra-long horizontal carbon nanotube obtained when the energization time is 5s in this embodiment, it can be seen that the longest carbon nanotube has 4.8mm, and the inferred growth rate reaches 960 μm/s, which is an order of magnitude higher than the fastest growth rate reported so far. As shown in Figure 3, it is a transmission electron microscope (TEM) picture of the ultra-long horizontal carbon nanotubes obtained when the power-on time is 5s in this embodiment, it can be clearly seen that the ultra-long horizontal carbon nanotubes have a hollow tubular structure, And the content of the single-wall carbon nanotube in the product exceeds 80wt%.

Example 2

In this embodiment, the method for rapidly preparing a horizontal array of ultralong carbon nanotubes on an ST-cut quartz substrate includes the following steps:

1) The connection of the catalyst loading and the electric heating device is the same as in Example 1.

2) Growth of the horizontal array of ultra-long carbon nanotubes: After the above-mentioned electric heating device is connected to the gas circuit, 300 sccm of Ar exhaust air is introduced for 5 minutes, and then 300 sccm of H ₂ is introduced for 5 minutes as reducing gas. Then feed 100 sccm of Ar/EtOH to prepare to start growing carbon nanotubes, apply 0.2A current to both ends of the carbon film, and the power-on time is 30s. to room temperature, a horizontal array of ultra-long carbon nanotubes is obtained as shown in Figure 4, the carbon nanotubes are arranged in parallel, and the density exceeds 1/μm.

Example 3

In this embodiment, the method for rapidly preparing a vertical array of carbon nanotubes on a SiO ₂ /Si substrate includes the following steps:

1) Catalyst preparation Electron beam evaporation technology is used to deposit the required Fe and Al ₂ O ₃ targets on the SiO ₂ /Si substrate at a rate of 0.02nm/s, the thickness of Fe is 0.8nm, and the thickness of Al ₂ O ₃ is respectively is 20nm, and the overall structure of the catalyst is Fe/Al ₂ O ₃ /SiO ₂ /Si.

2) The connection of the electric heating device is the same as in Embodiment 1.

3) Rapid growth of vertical arrays of carbon nanotubes: After the above-mentioned electric heating device is connected to the gas circuit, 100 sccm of Ar exhaust air is introduced for 5 minutes, and then 100 sccm of H ₂ is introduced for 5 minutes as reducing gas. Then feed 100 sccm of C ₂ H ₄ to prepare to start growing carbon nanotubes, apply 0.15A current to both ends of the carbon film, and the power-on time is 60s. After cooling down to room temperature, a rapidly growing vertical array of carbon nanotubes is obtained as shown in Figure 5, with a height exceeding 100 μm.

Comparative example 1

Comparison of horizontal arrays of carbon nanotubes grown in ordinary tube furnaces:

1) Catalyst loading is the same as in Example 1.

2) Put the catalyst-loaded SiO ₂ /Si substrate into a 1-inch tube furnace (TF 55035C-1Lindberg/Blue M), heat up to 950°C within 35 minutes, first pass 300 sccm of Ar to exhaust air for 5 minutes, and then pass Inject 100 sccm of H ₂ for 5 min as reducing gas. After feeding 50 sccm of Ar/EtOH to grow carbon nanotubes for 5 minutes, close the tube furnace, stop feeding the carbon source, keep hydrogen and argon to continue feeding, and naturally cool down to room temperature to obtain horizontal carbon nanotubes. The results are shown in Figure 6. The length of the carbon tubes does not exceed 1mm. Compared with the electric heating growth of the carbon film, the growth time is longer and the growth efficiency is lower.

Through Examples 1-3, it can be found that the rapid preparation of ultra-long horizontal carbon nanotubes can be realized by the above-mentioned technical solution of the present invention, the growth rate of ultra-long horizontal carbon nanotubes is fast, up to 960 μm/s, and the heating rate is fast , low energy consumption cost, good process stability, and is conducive to the macro preparation of ultra-long horizontal carbon nanotubes.

In addition, the inventors of the present case also conducted tests with other raw materials and conditions listed in this specification with reference to Example 1-Example 3, and also produced ultra-long horizontal carbon nanotubes with excellent properties. And through testing, it can be found that the ultra-long horizontal carbon nanotubes obtained by the above technical solution of the present invention have excellent electrical and optical properties, and have broad application prospects in the fields of nanoelectronic devices, energy conversion, biosensors, composite materials, etc. .

It should be understood that the above descriptions are only some implementations of the present invention, and it should be pointed out that other modifications and improvements can be made by those skilled in the art without departing from the inventive concept of the present invention. These all belong to the protection scope of the present invention.

Claims (10)

1. a kind of method quickly preparing ultra-long horizontal carbon nanotube, it is characterised in that including：

An at least catalyst layer is fixed in reative cell, and the catalyst layer is made to be connect with heating element heat conduction；

Carbon-source gas and carrier gas are passed through into the reative cell；

It grows with catalyst layer described in heating element heats and to form ultra-long horizontal carbon nanotube.

2. according to the method described in claim 1, it is characterized in that：The heating element uses carbon material film；Preferably, described The material of carbon material film includes any one or two or more combinations in carbon nanotube, carbon fiber and graphene；Preferably, The thickness of the carbon material film is 1~100 μm, and especially preferably 5~10 μm, conductivity is more than 10⁴S/m, intensity are more than 100MPa。

3. according to the method described in claim 2, it is characterized by comprising：

Catalyst layer is placed in reative cell, and catalyst layer is made to be connect with carbon material film heat conduction；

Carbon-source gas and carrier gas are passed through into the reative cell；

Make the carbon material film heating catalyst layer by way of being passed through electric current into the carbon material film and grow to be formed it is super Long horizontal carbon nanotube；Preferably, the intensity for being passed through the DC current of the carbon material film is 0.1~5A；

Preferably, the method specifically includes：

An at least catalyst layer is fixed in reative cell, and the catalyst layer is made to be connect with the carbon material film heat conduction；

It is passed through protective gas into the reative cell, to which indoor air discharge will be reacted；

Carbon-source gas and carrier gas are passed through into the reative cell；

With the carbon material film heats the catalyst layer and grows and to form ultra-long horizontal carbon nanotube；

Preferably, the protective gas includes inert gas；Preferably, the inert gas includes Ar；Preferably, the carrier gas Including inert gas；Preferably, the inert gas includes Ar or Ar and H₂。

4. according to the method described in claim 3, it is characterized in that：The catalyst layer is placed on the carbon material film, institute Carbon material film is stated also to be fixedly installed in the reative cell；And/or the method includes：Only with the heating element to described Catalyst layer is heated；Preferably, in the growth course of ultra-long horizontal carbon nanotube, the temperature of the catalyst layer is than anti- Answer high 800 DEG C of the temperature or more in remaining indoor region；Preferably, the catalyst layer is supported on substrate surface, and described Catalyst layer is connect through substrate with heating element heat conduction；Especially preferred, area load has the substrate of the catalyst layer straight It connects and is placed on the carbon material film；

And/or the catalyst layer includes a plurality of catalyst granules for being evenly distributed on substrate surface；Preferably, described to urge The size of catalyst particles is 0.5~5nm, and surface density is 10~1000/μm²；Preferably, the material packet of the catalyst granules Include metal nanoparticle and/or inorganic nanoparticles；Preferably, the metal nanoparticle include Fe, Co, Ni, Cu, Au, Mo, W, any one in Ru, Rh and Pd or two or more combinations；Preferably, the inorganic nanoparticles include SiO₂、TiO₂With Any one in ZnO or two or more combinations；Preferably, the substrate surface is horizontal plane；Preferably, the substrate Material includes SiO₂/ Si, ST cuts quartz, R cuts quartz, in the faces a alpha-aluminium oxide, the faces r alpha-aluminium oxide and magnesia any one or Two or more combinations；

And/or the carbon source to form the carbon-source gas includes liquid carbon source and/or gaseous carbon source；Preferably, the liquid Carbon source includes any one or two or more combinations in ethyl alcohol, acetone, benzene and toluene；Preferably, the gaseous carbon source packet Include any one in methane, ethylene and acetylene or two or more combinations.

5. a kind of method quickly preparing ultra-long horizontal carbon nanotube, it is characterised in that including：

The solution for including catalyst precursor is uniformly coated in substrate surface；

There is the substrate of the catalyst precursor to be fixed in reative cell area load, and make the substrate with as heating unit The carbon material film heat conduction of part connects；

It is passed through protective gas into the reative cell, to which indoor air discharge will be reacted；

It is passed through reducing gas, carbon-source gas and carrier gas into the reative cell, and is passed through electric current into the carbon material film and makes The carbon material film heats the substrate, and the catalyst precursor is made to be decomposed and restore, in the substrate surface shape At evenly dispersed a plurality of catalyst granules, and growth forms ultra-long horizontal carbon nanotube simultaneously.

6. according to the method described in claim 5, it is characterized by comprising：Only with the carbon material film to the catalyst granules It is heated；Preferably, in the growth course of ultra-long horizontal carbon nanotube, the catalyst layer of the catalyst granules formation 800 DEG C higher than the temperature in remaining region in reative cell of temperature or more；And/or the substrate is directly located the carbon material film On；Preferably, the substrate surface is horizontal plane；Preferably, the material of the substrate includes SiO₂/ Si, ST cuts quartz, R is cut Any one in quartz, the faces a alpha-aluminium oxide, the faces r alpha-aluminium oxide and magnesia or two or more combinations；

And/or the material of the carbon material film include in carbon nanotube, carbon fiber and graphene any one or it is two or more Combination；Preferably, the thickness of the carbon material film is 1~100 μm, and especially preferably 5~10 μm, conductivity is more than 10⁴S/ M, intensity are more than 100MPa；

And/or the size of the catalyst granules is 0.5~5nm, surface density is 10~1000/μm²；Preferably, described to urge The material of catalyst particles includes metal nanoparticle and/or inorganic nanoparticles；Preferably, the metal nanoparticle includes Any one in Fe, Co, Ni, Cu, Au, Mo, W, Ru, Rh and Pd or two or more combinations；Preferably, the inorganic nano Particle includes any one or two or more combinations in SiO2, TiO2 and ZnO；Preferably, described includes complex catalyst precursor The solution of body includes the Fe (OH) of a concentration of 0.01~0.5mmol/L₃/ EtOH solution.

7. according to the method described in claim 5, it is characterized in that：The protective gas includes inert gas；Preferably, described Inert gas includes Ar；And/or the carrier gas includes inert gas；Preferably, the inert gas includes Ar or Ar and H₂； And/or the carbon source to form the carbon-source gas includes liquid carbon source and/or gaseous carbon source；Preferably, the liquid carbon source Including any one or the two or more combinations in ethyl alcohol, acetone, benzene and toluene；Preferably, the gaseous carbon source includes first Any one in alkane, ethylene and acetylene or two or more combinations.

8. a kind of system quickly preparing ultra-long horizontal carbon nanotube, it is characterised in that including：

Reative cell, the reative cell has an at least air inlet and an at least gas outlet, and also fixation is set in the reative cell It is equipped with an at least catalyst layer, the catalyst layer can be contacted with the reaction gas for flowing to gas outlet from air inlet；

Heating element is fixedly installed in the reative cell and is connect with the catalyst layer heat conduction.

9. system according to claim 8, it is characterised in that：The heating element uses carbon material film；Preferably, described The material of carbon material film includes any one or two or more combinations in carbon nanotube, carbon fiber and graphene；Preferably, The thickness of the carbon material film is 1~100 μm, and especially preferably 5~10 μm, conductivity is more than 10⁴S/m, intensity are more than 100MPa。

10. system according to claim 8, it is characterised in that：The catalyst layer is placed on the carbon material film；It is excellent Choosing, the catalyst layer is supported on substrate surface, and the catalyst layer is connect through substrate with heating element heat conduction；It is excellent Choosing, area load has the substrate of the catalyst layer to be directly located on the carbon material film；Preferably, the catalyst layer A plurality of catalyst granules including being evenly distributed on substrate surface；Preferably, the size of the catalyst granules be 0.5~ 5nm, surface density are 10~1000/μm²；Preferably, the material of the catalyst granules includes metal nanoparticle and/or nothing Machine nano particle；Preferably, the metal nanoparticle includes any one in Fe, Co, Ni, Cu, Au, Mo, W, Ru, Rh and Pd Kind or two or more combinations；Preferably, the inorganic nanoparticles include SiO₂、TiO₂With any one or two kinds in ZnO Above combination；Preferably, the substrate surface is horizontal plane；Especially preferred, the material of the substrate includes SiO₂/Si、 ST cuts quartz, R cuts quartz, any one or two or more combinations in the faces a alpha-aluminium oxide, the faces r alpha-aluminium oxide and magnesia；

And/or the carbon material film is also electrically connected with more than two spaced electrodes, the electrode is electrically connected to a power source； Preferably, the electrode includes copper electrode.