Single-walled carbon nanotube and method and apparatus for preparing the same

Abstract

The application discloses a single-wall carbon nanotube and a preparation method and device thereof. The device comprises a catalyst conveying unit, a carbon source conveying unit, a carbon nanotube growth unit and a product collecting unit. The catalyst conveying unit is used for conveying a left airflow containing a cyclodextrin@metallocene guest supramolecular complex in a first direction. The carbon source conveying unit is used for conveying a right airflow containing a carbon source in a second direction. The first direction airflow and the second direction airflow intersect to form an upward airflow pointing to the product collecting unit. The application realizes controllable release of catalyst precursors based on supramolecular assembly, promotes uniform formation of nanoscale catalysts, avoids influence of mixed factors on catalyst formation, forms nanoscale catalyst particles through dissociation and growth, then intersects with the carbon source airflow to form a vortex to rapidly generate carbon tubes, and the generated carbon tube products can be discharged in time, so that continuous preparation of the carbon tubes is realized.

Description

Technical Field

[0001] This invention relates to the fields of supramolecular chemistry and carbon nanomaterial preparation technology, and particularly to a single-walled carbon nanotube and its preparation method and apparatus. More specifically, it designs a method for preparing single-walled carbon nanotubes based on a supramolecular chemistry strategy. Background Technology

[0002] Single-walled carbon nanotubes (SWCNTs) are quasi-one-dimensional nanomaterials formed by rolling up a single layer of graphene along a specific helical direction. Their diameters typically range from 0.5 to 2 nm, and they possess unique quantum confinement effects, chirality-dependent electronic structures, and anisotropic physicochemical properties. Since Iijima's initial discovery of carbon nanotubes in 1991, SWCNTs have become a research hotspot in nanotechnology due to their excellent mechanical strength (theoretical Young's modulus of 1 TPa, tensile strength of 50 GPa), electrical properties (conductivity higher than copper, tunable semiconductor bandgap), and optical response (surface plasmon resonance effect). They show broad application prospects in flexible electronic devices, composite material reinforcements, biomedical imaging and therapy, and efficient catalyst supports.

[0003] However, current large-scale SWCNT preparation technologies still face multiple technical bottlenecks: First, while existing chemical vapor deposition (CVD) methods can achieve controllable growth, they are limited by the distribution of catalyst active sites and reaction kinetics, making it difficult to achieve continuous preparation with high purity and high yield. Second, traditional arc discharge methods suffer from low graphite utilization (<30%) and numerous byproducts (fullerenes, graphite fragments), leading to high post-processing costs. Third, although laser ablation can obtain highly crystalline products, its energy input efficiency is low (only about 5% of laser energy is converted into carbon nanotubes), making it difficult to meet industrial standards for energy consumption in large-scale production. These technical shortcomings limit the integration of SWCNTs into semiconductor devices (such as field-effect transistors with mobility <100 cm⁻¹). 2Practical applications in key areas such as the strength of composite materials (reinforcing efficiency is 40-60% lower than theoretical values) and the development of biocompatible materials (immunogenic residual rate >15%) are limited. Therefore, developing novel preparation technologies that combine atomic-level structural controllability with compatibility for large-scale preparation has become a core scientific issue in overcoming the bottleneck of carbon-based nanomaterial industrialization. Chinese invention patent CN19306212A provides a two-step apparatus and method for preparing single-walled carbon nanotubes. This method provides an apparatus for preparing single-walled carbon nanotubes, mainly including providing a catalyst, carbon source, and etchant through different channels into a reaction chamber, and causing the airflows in opposite directions to converge to form a vortex. The vortex avoids the problem of local stagnation and blockage of tangential laminar flow, thereby avoiding the impact on the quality and continuous growth of carbon nanotubes. It avoids the mutual interference that occurs in the early stage of the reaction in traditional preparation methods, especially avoiding the mutual interference between the carbon source and the catalyst, providing a controllable and stable catalyst particle formation process, and realizing the controllable preparation of catalyst nanoparticles and the orderly separation of carbon nanotube growth steps. However, the device also includes a third airflow channel that interferes with the convergence of the two opposing airflow channels, thereby affecting the formation and stability of the vortex.

[0004] Supramolecular chemical assembly technology constructs supramolecular systems with dynamic and reversible properties based on intermolecular non-covalent interactions (such as hydrogen bonds, π-π stacking, metal coordination, hydrophobic effects, etc.). Compared with traditional covalent bonded material design, it has three core advantages: (1) Dynamic adaptability: Through reversible weak interactions between host and guest, the system can respond to external stimuli (pH, temperature, light field, etc.) in milliseconds and achieve molecular-level "on / off" regulation, such as the release of drugs in biological organisms in response to pH in crown ether-ammonium salt system; (2) Modular structure: By adopting a "building block" assembly strategy, new functional supramoleculars can be quickly constructed by changing the host molecule (cyclodextrin, calixarene, cucurbituril) or guest functional groups; (3) Interface engineering advantages: The host-guest interface can form a directional dipole field (such as the CH…π interaction between β-cyclodextrin and guests), making the assembly significantly better than traditional covalent materials in terms of photoelectric conversion efficiency, molecular recognition specificity, and other performance indicators.

[0005] This invention is based on a supramolecular chemistry strategy, which assembles a catalyst precursor with a supramolecular host compound to form a supramolecular complex, achieving non-covalent bonding at the molecular level. Under certain reaction conditions, the controlled release of the catalyst precursor is realized, which will facilitate the formation of nanoscale catalysts and the subsequent growth of carbon nanotubes. This invention is expected to break through the bottleneck of both atomic-level structural controllability and compatibility with large-scale preparation. Summary of the Invention

[0006] In view of the shortcomings of the prior art, the purpose of this invention is to provide an apparatus and method for preparing single-walled carbon nanotubes based on a supramolecular chemistry strategy.

[0007] To achieve the aforementioned objectives, the technical solution adopted by this invention includes:

[0008] In a first aspect, the present invention provides a method for preparing single-walled carbon nanotubes based on a supramolecular chemistry strategy, comprising: using a first gas flow containing a cyclodextrin@cendolite metal supramolecular complex and a polymerization inhibitor, and a second gas flow containing a carbon source, such that the first gas flow and the second gas flow converge in opposite directions and at the same horizontal line to form a vortex; the cyclodextrin@cendolite metal supramolecular complex, the polymerization inhibitor, and the carbon source react in contact within the vortex, and the carbon nanotube product formed in the vortex and driven by the flow field of the vortex is collected above the vortex.

[0009] The catalyst precursor is released from the cyclodextrin@cenyl metal guest supramolecular complex and further dissociates and grows until it forms nanoscale catalyst particles. Then it encounters the carbon source gas flow in the opposite direction and rapidly generates carbon nanotubes.

[0010] This invention achieves the controlled release of catalyst precursors based on a supramolecular assembly strategy, which is beneficial to the uniform formation of nanoscale catalysts and further reduces the influence of impurities on catalyst formation. The vortex formed by the opposing confluence facilitates full contact between the catalyst and the carbon source, and the generated carbon nanotube products are discharged in time, thereby realizing the continuous preparation of carbon nanotubes.

[0011] In some specific embodiments, the cyclodextrin@metallocene supramolecular complex is assembled from β-cyclodextrin and its derivatives with metallocene in a solvent.

[0012] Preferably, the cyclopentadiene metal is cobalt dicene, nickel dicene, ferrocene, or their derivatives.

[0013] Preferably, the carbon source includes any one or a combination of two or more of methane, ethane, carbon monoxide, ethylene, propylene, methanol, ethanol, toluene, acetonitrile, and acetone.

[0014] Preferably, the carrier gas of the first gas flow and / or the second gas flow includes any one or a combination of two or more of argon, helium, and nitrogen.

[0015] Preferably, the polymerization inhibitor is a sulfur-containing compound and / or elemental sulfur.

[0016] More preferably, the polymerization inhibitor is at least one of thiourea and thiophene.

[0017] Preferably, the volume ratio of carbon source to carrier gas in the second gas flow is 1:0 to 1000.

[0018] Preferably, the flow rate ratio of the first airflow to the second airflow is 1:0.01 to 100.

[0019] In some specific embodiments, in the cyclodextrin@metallocene supramolecular complex, the molar ratio of the β-cyclodextrin and its derivatives to the metallocene is 1:0.1 to 1.

[0020] In some specific embodiments, the solvent is any one or a combination of two or more of water, methanol, ethanol, isopropanol, acetonitrile, diethyl ether, dichloromethane, chloroform, acetone, toluene, xylene, cyclohexane, dimethyl sulfoxide (DMSO), and N,N-dimethylformamide (DMF).

[0021] In some specific embodiments, the reaction temperature is 600–2000°C.

[0022] As a second aspect of the invention, the present invention also provides a single-walled carbon nanotube prepared by a supramolecular chemical strategy, which is obtained by the preparation method described above.

[0023] Preferably, the purity of the single-walled carbon nanotubes is 60-95%, and the G / D ratio is greater than 30.

[0024] As a third aspect of the invention, the present invention also provides an apparatus for preparing single-walled carbon nanotubes by the above-described preparation method, comprising: a catalyst delivery unit, a carbon source delivery unit, a carbon nanotube growth unit, and a product collection unit.

[0025] In some specific embodiments, the catalyst delivery unit, carbon source delivery unit, and product collection unit are fixed on the cavity wall of the carbon nanotube growth unit and communicate with the internal reaction chamber of the carbon nanotube growth unit.

[0026] In some specific embodiments, the catalyst delivery unit is used to introduce a first gas flow containing the cyclodextrin@cenyl metal supramolecular complex in a first direction, and the carbon source delivery unit is used to introduce a second gas flow containing the carbon source in a second direction.

[0027] Specifically, the first direction and the second direction are opposite and are on the same horizontal line.

[0028] More specifically, the first airflow and the second airflow converge to form a vortex airflow.

[0029] In some specific embodiments, the product collection unit is positioned above the carbon nanotube growth unit to collect the carbon nanotube products discharged by the upward airflow along the vortex.

[0030] In some specific embodiments, the catalyst delivery unit and the carbon source delivery unit are respectively disposed on both sides of the carbon nanotube growth unit, and the first direction and the second direction are both horizontally arranged and pointing towards the center of the vortex.

[0031] The preparation of single-walled carbon nanotubes using the technical solution of this invention can significantly increase the yield of nanotubes, reaching 1-10 kg / day.

[0032] Compared with the prior art, the beneficial effects of the present invention include at least the following:

[0033] 1. Compared with the traditional method of simply inputting catalyst precursors into the growth unit, the technical solution of this invention, based on a supramolecular chemistry strategy, allows for the controllable release of cyclodextrin@cendolite metal supramolecular complexes after the reaction unit is delivered. This effectively avoids the formation of ineffective catalysts caused by low temperatures at the front end. The more uniform nanoscale particles significantly contribute to the growth of high-quality carbon nanotubes. The vortex formed by the opposing airflow facilitates the thorough mixing of catalyst particles and carbon source, and further facilitates the timely removal of carbon nanotube products formed in the growth region. Ultimately, this invention achieves the preparation of single-walled carbon nanotubes that combine atomic-level structural controllability with compatibility for large-scale preparation.

[0034] 2. The apparatus and method provided by the present invention deliver the catalyst precursor (together with the polymerization inhibitor) and the carbon source to the growth unit through sample introduction channels in opposite directions, thereby avoiding the mutual interference factors of the mixed input of catalyst precursor and carbon source in the traditional method and realizing the graded and distributed control.

[0035] The above description is merely an overview of the technical solution of the present invention. In order to enable those skilled in the art to better understand the technical means of this application and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described below in conjunction with detailed drawings. Attached Figure Description

[0036] Figure 1 A schematic diagram of the device structure for preparing single-walled carbon nanotubes based on a supramolecular chemistry strategy, provided as a typical embodiment of the present invention;

[0037] Figure 2 A scanning electron microscope image of the product obtained in a typical embodiment of the present invention;

[0038] Figure 3 A transmission electron microscope image of the product obtained in a typical embodiment of the present invention.

[0039] Figure 4 The Raman spectrum of the product obtained in a typical embodiment of the present invention is shown.

[0040] Figure 5Thermogravimetric analysis (TGA) diagram of the product obtained in a typical embodiment of the present invention;

[0041] Figure 6 Thermogravimetric analysis diagram of the product obtained in Comparative Example 2 of this invention;

[0042] Figure 7 The Raman spectrum of the product obtained in Comparative Example 2 of this invention is shown.

[0043] Figure 8 Thermogravimetric analysis diagram of the product obtained in Comparative Example 3 of this invention;

[0044] Figure 9 This is the Raman spectrum of the product obtained in Comparative Example 3 of this invention.

[0045] Explanation of reference numerals in the attached drawings: 1. Catalyst delivery unit; 2. Carbon source delivery unit; 3. First mixing unit; 4. Second mixing unit; 5. Carbon nanotube growth unit; 6. Product collection unit; 7. Material receiving unit. Detailed Implementation

[0046] In view of the shortcomings of the prior art, the inventors of this invention, through long-term research and extensive practice, have proposed the technical solution of this invention. The following will further explain and illustrate this technical solution, its implementation process, and its principles.

[0047] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may be implemented in other different ways, and therefore the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0048] Moreover, relational terms such as “left side” and “right side” are used merely to distinguish one component or method step from another that has the same name, without necessarily requiring or implying any such actual relationship or order between these components or method steps.

[0049] A specific embodiment of the present invention provides a method for preparing single-walled carbon nanotubes based on a supramolecular chemistry strategy, comprising the following steps: introducing a left-side airflow containing a cyclodextrin@metallocene supramolecular complex and a polymerization inhibitor into a carbon nanotube growth unit in a first direction, and introducing a right-side airflow containing a carbon source into the carbon nanotube growth unit in a second direction, wherein the first and second directions are opposite and at the same horizontal line so that the two airflows converge to form a vortex; and collecting the carbon nanotube products formed in the vortex and driven by the flow field of the vortex above the vortex.

[0050] In some embodiments, the cyclodextrin is any one or a combination of two or more of β-cyclodextrin and its derivatives, but is not limited thereto.

[0051] In some implementations, the cyclopentadienyl metal is any one or a combination of two or more of cobalt dicene, nickel dicene, ferrocene and their derivatives, but is not limited thereto.

[0052] In some embodiments, the carbon source includes, but is not limited to, any one or a combination of two or more of methane, ethane, carbon monoxide, ethylene, propylene, methanol, ethanol, toluene, acetonitrile, and acetone.

[0053] In some embodiments, the carrier gas of the left and / or right airflow includes any one or a combination of two or more of argon, helium, and nitrogen, but is not limited thereto.

[0054] In some embodiments, the polymerization inhibitor is a sulfur-containing compound.

[0055] In some implementations, the volume ratio of carbon source to carrier gas in the right airflow is 1:0 to 1000; the flow rate ratio of the left airflow to the right airflow is 1:0.01 to 100.

[0056] In some embodiments, the cyclodextrin@metallocene supramolecular complex is assembled from β-cyclodextrin and its derivatives with metallocene in a solvent at a stoichiometric ratio of 1:0.1-1.

[0057] In some embodiments, the solvent is any one or a combination of two or more of water, methanol, ethanol, isopropanol, acetonitrile, diethyl ether, dichloromethane, chloroform, acetone, toluene, xylene, cyclohexane, dimethyl sulfoxide (DMSO), and N,N-dimethylformamide (DMF), but is not limited thereto; the cyclodextrin@metallocene supramolecular complex exists in the solvent in a uniformly dispersed or precipitated form, depending on the tunable solubility of β-cyclodextrin compounds and metallocene.

[0058] In some implementations, the temperature of the carbon nanotube growth unit is 600-2000°C.

[0059] In some implementations, the purity of the single-walled carbon nanotubes prepared by the method can reach 60-95%, the G / D ratio is greater than 30, and the yield can reach 1-10 kg / day.

[0060] This invention first involves supramolecularly assembling a catalyst precursor with a supramolecular macrocyclic cyclodextrin host to form a cyclodextrin@cenyl metalloenzyme supramolecular complex. This complex is then directionally transported from one side of the reactor to a specific temperature region to release, pyrolyze, and grow the catalyst precursor until it forms the catalyst. A carbon source is transported from the other side of the reactor to a carbon nanotube growth chamber, where it encounters a mixed gas stream containing the catalyst, allowing for thorough mixing and carbon nanotube growth. Driven by a thermal field and vortex, the carbon nanotube product is discharged upwards into a collection unit.

[0061] Existing technologies often employ a one-step mixed approach. For example, some existing technologies propose using chemical vapor deposition to directly deliver catalyst precursors to prepare single-walled carbon nanotubes. However, in these existing technologies, the formation of catalyst particles and the growth of carbon nanotubes are often intertwined on both temporal and spatial scales. The crucial catalyst nucleation process is particularly uncontrollable, significantly impacting the quality of the subsequent carbon nanotubes. The inventors discovered that this hinders the control of microscopic variables and therefore introduced supramolecular chemical assembly characteristics to achieve controllable catalyst nucleation, enabling large-scale preparation with high purity and high crystallinity.

[0062] A specific embodiment of the present invention also provides an apparatus for preparing single-walled carbon nanotubes based on a supramolecular chemistry strategy, comprising: a catalyst delivery unit, a carbon source delivery unit, a carbon nanotube growth unit, and a product collection unit; the catalyst delivery unit, carbon source delivery unit, and product collection unit are fixed on the cavity wall of the carbon nanotube growth unit and communicate with the internal reaction chamber of the carbon nanotube growth unit; the catalyst delivery unit is disposed on one side (first direction) of the carbon nanotube growth unit, and the carbon source delivery unit is disposed on the opposite side (second direction) of the carbon nanotube growth unit, and the first direction and the second direction are on the same horizontal line; the catalyst delivery unit is disposed on one side (first direction) of the carbon nanotube growth unit, and the carbon source delivery unit is disposed on the opposite side (second direction) of the carbon nanotube growth unit, and the first direction and the second direction are on the same horizontal line; the catalyst delivery unit is disposed on one side (first direction) of the carbon nanotube growth unit, and the carbon source delivery unit is disposed on the opposite side (second direction) of the carbon nanotube growth unit, and the first direction and the second direction are on the same horizontal line; the catalyst delivery unit is disposed on one side (first direction) of the carbon nanotube growth unit, and the carbon source delivery unit is disposed on the opposite side (second direction) of the carbon nanotube growth unit, and the carbon source delivery unit is disposed on the opposite side (second direction) of the carbon nanotube growth unit, and the carbon source delivery unit is disposed on the opposite side (second direction), ... The agent delivery unit is used to introduce a left-side airflow containing the cyclodextrin@cenyl metal supramolecular complex in a first direction, and the carbon source delivery unit is used to introduce a right-side airflow containing the carbon source in a second direction. The airflows in the first and second directions converge to form a vortex airflow. The carbon nanotube growth unit is also equipped with a heating element to regulate the temperature of the carbon nanotube growth unit. Under the influence of the thermal field, the vortex forms an upward airflow pointing towards the product collection unit. The product collection unit is located above the carbon nanotube growth unit and is used to collect the carbon nanotube products discharged along the upward airflow. The product collection unit includes a discharge pipe at the upper end of the carbon nanotube growth unit, a product collection chamber, and a tail gas treatment module.

[0063] From the perspective of the preparation principle of carbon nanotubes, the sequence is as follows: (1) First, catalyst particles of suitable size are formed; (2) Second, the catalyst particles come into contact with the carbon source, and then carbon nanotubes grow. It can be seen that no matter which method is used, the core should conform to the above principle. However, the difficulty in the preparation of single-walled carbon nanotubes lies precisely in how to control the homogeneous preparation of catalyst particles and under what conditions they come into contact with the carbon source. Therefore, from the perspective of controlling variables, the disadvantage of the one-step mixing method is that there are too many variables in the same time and space scale, making it difficult to achieve the preparation of high-quality, high-yield single-walled carbon nanotubes. The advantage of this invention is that the preparation of the catalyst is separated, and the catalyst particles are prepared controllably based on the supramolecular chemical assembly strategy. In addition, the opposing mixed gas flow is also conducive to the full contact between the catalyst and the carbon source and the timely discharge of the product.

[0064] It should be noted that the above-mentioned specific technical details are some exemplary details of the preparation of single-walled carbon nanotubes in this invention, which are mainly for reference by those skilled in the art. They do not mean that the scope of implementation based on the core idea of ​​this invention is limited to these details. The devices or methods designed based on the key concept of this invention are all within the scope of feasibility. The specific reaction materials and conditions can refer to the precedents of single-walled carbon nanotube growth mentioned in many existing technologies or develop new reaction materials and conditions on their own.

[0065] The above technical solution effectively isolates the preparation of catalysts based on supramolecular chemical assembly strategy, making the release of catalyst precursors change from disorder to controllable release, which is conducive to the preparation of uniform nanoscale catalyst particles. The design of counter-current airflow is conducive to full contact between catalyst fluid and carbon source fluid, improving catalyst utilization efficiency, and at the same time facilitating the timely discharge of generated carbon nanotube products. Overall, it realizes the transformation of the carbon nanotube growth process from disorder to order.

[0066] The technical solution of the present invention will be further described in detail below through several embodiments and in conjunction with the accompanying drawings. However, the selected embodiments are only for illustrating the present invention and do not limit the scope of the present invention.

[0067] Example 1

[0068] This embodiment illustrates a method for preparing single-walled carbon nanotubes based on a supramolecular chemistry strategy. This method is combined with an apparatus for preparing single-walled carbon nanotubes. (See [link to relevant documentation]). Figure 1 It includes a catalyst delivery unit 1, a carbon source delivery unit 2, a carbon nanotube growth unit 5, and a product collection unit 6; wherein, the catalyst delivery unit 1 is built into the first mixing unit 3 and communicates with the carbon nanotube growth unit 5, the carbon source delivery unit 2 is built into the second mixing unit 4 and communicates with the carbon nanotube growth unit 5, and the first mixing unit 3 and the second mixing unit 4 are fixed on opposite sides of the carbon nanotube growth unit 5.

[0069] The catalyst delivery unit 1, the carbon source delivery unit 2, and the product collection unit 6 are fixed on the cavity wall of the carbon nanotube growth unit 5 and are connected to the reaction chamber inside the carbon nanotube growth unit 5. The catalyst delivery unit 1 is located on one side of the carbon nanotube growth unit 5, and the carbon source delivery unit 2 is located on the opposite side of the carbon nanotube growth unit 5. The relative directions of the catalyst delivery unit 1 and the carbon source delivery unit 2 are on the same horizontal line.

[0070] The catalyst delivery unit 1 is equipped with an airflow for introducing a cyclodextrin@cenyl metal supramolecular complex. The carbon source delivery unit 2 is used to introduce a carbon source-containing airflow in opposite directions, and the airflows in opposite directions on both sides converge to form a vortex. The carbon nanotube growth unit 5 is also equipped with a heating element to regulate the temperature of the carbon nanotube growth unit. Under the influence of the thermal field, the vortex forms an upward airflow pointing towards the product collection unit 6. The product collection unit 6 is located above the carbon nanotube growth unit 5 and is used to collect the carbon nanotube products discharged along the upward airflow. The product collection unit 6 includes a receiving unit 7 at the upper end of the carbon nanotube growth unit. The receiving unit includes a discharge pipe, a product collection chamber, and a tail gas treatment module.

[0071] Specifically, the method for preparing single-walled carbon nanotubes based on supramolecular chemistry includes the following steps:

[0072] Step 1: Purge the air from the reaction system using a vacuum pump and fill it with helium. Turn on the electric heating device of the carbon nanotube growth unit and set the temperature to 1100℃.

[0073] Step 2: After the set temperature is reached, β-cyclodextrin@cobaltene (5 g / min), β-cyclodextrin@nickel dicene (5 g / min), sulfur (5 g / min), and helium (100 L / min) are introduced into the catalyst delivery unit 1 on one side of the carbon nanotube growth unit 5. The catalyst precursor complex is released and decomposed at high temperature, and then further grown to the nanoscale.

[0074] Step 3: A mixture of propylene (40L / min) and helium (60L / min) is input through carbon source delivery unit 2. As the mixture is input, it meets the airflow in the opposite direction containing the catalyst, forming a vortex in the carbon nanotube growth chamber. Under the action of the catalyst, the black carbon nanotube product is generated instantly and enters the product collection unit 6 with the upward airflow of the vortex.

[0075] Step 4: Subsequently, the product enters the receiving unit 7 through the material outlet, and the gas is discharged after passing through the tail gas treatment device.

[0076] After the reaction was completed, an appropriate amount of sample was taken for characterization. The microstructure, size, crystallinity, and carbon content of the single-walled carbon nanotubes were determined by scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, and thermogravimetric analysis, respectively. For specific characterization methods, please refer to GB / T 32869-2016, GB / T 30534-2014, GB / T 32871-2016, and GB / T 24490-2009.

[0077] Characterization results as follows Figures 2-5 As shown.

[0078] See Figure 2 The image shows a SEM image of the prepared single-walled carbon nanotubes. As can be seen from the image, single-walled carbon nanotubes were successfully prepared in this embodiment, and the size was uniform with a bundle size of 50-100 μm.

[0079] See Figure 3 The results of high-resolution transmission electron microscopy characterization show that the catalyst particles are of uniform size.

[0080] See Figure 4 The Raman spectra of the prepared carbon nanotubes can be obtained at 1570 cm⁻¹. -1 1350cm -1 and 0-200cm -1 The G band shows a sharp graphite peak, an unusually small disorder peak (D band), and a highly distinct radial breathing pattern characteristic peak (RBM). The G / D ratio is 35, indicating that the carbon nanotubes have a high degree of crystallinity.

[0081] See Figure 5 Thermogravimetric analysis of the prepared carbon nanotubes showed that the initial single-walled carbon nanotubes had a carbon content of ~85 wt%.

[0082] Example 2

[0083] An apparatus and method for preparing single-walled carbon nanotubes based on a supramolecular chemistry strategy, comprising:

[0084] Step 1: Purge the air from the reaction system using a vacuum pump and fill it with nitrogen. Turn on the electric heating device of the carbon nanotube growth unit and set the temperature to 1700℃.

[0085] Step 2: After the set temperature is reached, β-cyclodextrin@cobaltene (7 g / min), β-cyclodextrin@ferrocene (3 g / min), thiourea (7 g / min), and nitrogen (120 L / min) are introduced into the left side of the carbon nanotube growth unit. The catalyst precursor complex is released and decomposed at high temperature, and then further grown to the nanoscale.

[0086] Step 3: A mixture of acetylene (40 L / min) and nitrogen (80 L / min) is introduced through the carbon source delivery unit. As the mixture is introduced, it encounters the opposing gas flow containing the catalyst, creating a vortex within the carbon nanotube growth chamber. Under the influence of the catalyst, the black carbon nanotube product is instantly generated.

[0087] Step 4: The product then enters the product collection unit through the material outlet, and the gas is discharged after passing through the tail gas treatment device.

[0088] The obtained product is similar to that of Example 1, with high purity and high crystallinity. It also exhibits excellent stability during continuous batch preparation, with a G / D ratio of 38 and a product purity of ~85%.

[0089] Example 3

[0090] An apparatus and method for preparing single-walled carbon nanotubes based on a supramolecular chemistry strategy, comprising:

[0091] Step 1: Purge the air from the reaction system using a vacuum pump and fill it with argon gas. Turn on the electric heating device of the carbon nanotube growth unit and set the temperature to 1000℃.

[0092] Step 2: After the set temperature is reached, β-cyclodextrin@cobalt 1, β-cyclodextrin@ferrocene 1, β-cyclodextrin@nickel 1, thiophene 10 g / min and argon 150 L / min are introduced into the left side of the carbon nanotube growth unit. The catalyst precursor complex is released and decomposed at high temperature, and then further grown to the nanoscale.

[0093] Step 3: A mixture of ethylene (50 L / min) and argon (100 L / min) is introduced through the carbon source delivery unit. As the mixture is introduced, it encounters the opposing gas flow containing the catalyst, creating a vortex within the carbon nanotube growth chamber. Under the influence of the catalyst, the black carbon nanotube product is instantly generated.

[0094] Step 4: The product then enters the product collection unit through the material outlet, and the gas is discharged after passing through the tail gas treatment device.

[0095] The obtained product is similar to that in Example 1, with high purity and high crystallinity. It also exhibits excellent stability during continuous batch preparation, with a G / D ratio of 30 and a product purity of ~80%.

[0096] Comparative Example 1

[0097] This comparative example is largely the same as Example 1, with the main difference being:

[0098] The carbon source delivery unit is turned off, and the mixture of propylene (40L / min) and helium (60L / min) is mixed with the original catalyst precursor, polymerization inhibitor and carrier gas and injected into the carbon nanotube growth unit from the catalyst delivery unit on the left.

[0099] All other reaction conditions and reactants remained the same as in Example 1.

[0100] In this comparative example, since the catalyst precursor, polymerization inhibitor, and carbon source are introduced in the same direction, the cracking and growth process of the catalyst precursor is affected by the carbon source, interfering with the formation of catalyst particles. Furthermore, the co-directional airflow cannot form vortices, preventing the product from being directionally discharged to the collection unit and hindering continuous production.

[0101] Comparative Example 2

[0102] This comparative example is largely the same as Example 1, with the main difference being:

[0103] Sulfur was instead introduced from the carbon source transport unit.

[0104] All other reaction conditions and reactants remained the same as in Example 1.

[0105] like Figure 6 and Figure 7 As shown, the product discharge was smooth in this comparative example. However, due to the lack of polymerization inhibitor after the catalyst precursor was cracked, the catalyst particle size distribution was disordered, and large catalyst particles were formed, resulting in the loss of catalytic activity of the catalyst particles. The G / D ratio of the obtained product was 1:1. Obviously, the crystallinity (G / D ratio) and purity were significantly reduced compared with Example 1.

[0106] Comparative Example 3

[0107] This comparative example is largely the same as Example 1, with the main difference being:

[0108] The cyclodextrin@locene metal supramolecular complex was replaced with cobalt dicene (0.7 g / min) and nickel dicene (0.7 g / min).

[0109] All other reaction conditions and reactants remained the same as in Example 1.

[0110] like Figure 8 and Figure 9 As shown, in this comparative example, the product discharge was smooth, but due to the lack of supramolecular cyclodextrin encapsulation of the cyclocenyl metal, the catalyst precursor cracking occurred earlier and was more widespread on the time scale, resulting in a wider distribution of catalyst particle size. The G / D ratio of the obtained product was 7. Obviously, the crystallinity (G / D ratio) and purity were lower than those in Example 1.

[0111] Based on the above embodiments and comparative analysis, it is evident that the supramolecular chemical assembly strategy introduced in this invention is beneficial for controlling the release of catalyst precursors, transforming the catalyst preparation process from disordered to ordered in both time and space. This effectively avoids the interference of multiple variables in traditional methods and facilitates the formation of catalyst particles with uniform size distribution. Simultaneously, the design of the opposing airflow promotes the formation of vortices, which not only improves the sufficient contact between the catalyst particles and the carbon source but also facilitates the timely discharge of products, thereby achieving both high crystallinity and large-scale carbon nanotube preparation.

[0112] It should be understood that the above embodiments are merely illustrative of the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing single-walled carbon nanotubes, characterized in that, include: A gas containing cyclodextrin@locene metal supramolecular complex and polymerization inhibitor is used as the first gas flow, and a carbon source is used as the second gas flow. The first gas flow and the second gas flow are made to converge in opposite directions and at the same horizontal line to form a vortex. The cyclodextrin@locene metal supramolecular complex, the polymerization inhibitor, and the carbon source react in contact in the vortex, and carbon nanotube products formed in the vortex and driven by the flow field of the vortex are collected above the vortex. The reaction temperature is 600~2000℃; The cyclodextrin@metallocene supramolecular complex is assembled from β-cyclodextrin and its derivatives with metallocene in a solvent; The carbon source includes any one or a combination of two or more of methane, ethane, carbon monoxide, ethylene, propylene, methanol, ethanol, toluene, acetonitrile, and acetone. The single-walled carbon nanotubes have a purity of 60-95% and a G / D ratio greater than 30.

2. The preparation method according to claim 1, characterized in that, The cyclopentadiene metals are cobalt dicene, nickel dicene, ferrocene, and their derivatives.

3. The preparation method according to claim 1, characterized in that, The carrier gas of the first gas flow and / or the second gas flow includes any one or a combination of two or more of argon, helium, and nitrogen.

4. The preparation method according to claim 1, characterized in that, The polymerization inhibitor is a sulfur-containing compound and / or elemental sulfur.

5. The preparation method according to claim 1, characterized in that, The volume ratio of carbon source to carrier gas in the second gas flow is 1:2 or 2:

3.

6. The preparation method according to claim 1, characterized in that, The flow rate ratio of the first airflow to the second airflow is 1:0.01~100.

7. The preparation method according to claim 1, characterized in that, In the cyclodextrin@metallocene supramolecular complex, the molar ratio of the β-cyclodextrin and its derivatives to the metallocene is 1:0.1~1.

8. The preparation method according to claim 1, characterized in that, The polymerization inhibitor is at least one of thiourea and thiophene.

9. The preparation method according to claim 1, characterized in that, The solvent is any one or a combination of two or more of the following: water, methanol, ethanol, isopropanol, acetonitrile, diethyl ether, dichloromethane, chloroform, acetone, toluene, xylene, cyclohexane, dimethyl sulfoxide, and N,N-dimethylformamide.

10. A single-walled carbon nanotube, prepared by the preparation method according to any one of claims 1-9.

11. An apparatus for preparing single-walled carbon nanotubes by the preparation method according to any one of claims 1-9, or an apparatus for preparing single-walled carbon nanotubes as described in claim 10, characterized in that, include: Catalyst delivery unit, carbon source delivery unit, carbon nanotube growth unit, and product collection unit; The catalyst delivery unit, carbon source delivery unit, and product collection unit are fixed on the cavity wall of the carbon nanotube growth unit and are connected to the reaction chamber inside the carbon nanotube growth unit. The catalyst delivery unit is used to introduce a first gas flow containing cyclodextrin@locene metal supramolecular complex in a first direction, and the carbon source delivery unit is used to introduce a second gas flow containing carbon source in a second direction. The first direction and the second direction are opposite and on the same horizontal line; The first airflow and the second airflow converge to form a vortex airflow; The product collection unit is positioned above the carbon nanotube growth unit and is used to collect the carbon nanotube products discharged by the upward airflow along the vortex.

12. The apparatus according to claim 11, characterized in that, The catalyst delivery unit and the carbon source delivery unit are respectively disposed on both sides of the carbon nanotube growth unit, and the first direction and the second direction are both horizontally arranged and pointing towards the center of the vortex.

13. The apparatus according to claim 11, characterized in that, The product collection unit includes a discharge pipe at the upper end of the carbon nanotube growth unit, a product collection chamber, and an exhaust gas treatment module.

14. The apparatus according to claim 11, characterized in that, The carbon nanotube growth unit also includes a heating element for adjusting the temperature of the carbon nanotube growth unit. The vortex, under the influence of the thermal field, forms an upward airflow pointing towards the product collection unit of the single-walled carbon nanotubes.

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