Single-walled carbon nanotube, apparatus for manufacturing the same, and method for manufacturing the same

Abstract

The application belongs to the technical field of nanometer material preparation, and particularly relates to a single-wall carbon nanometer tube, a preparation device thereof and a preparation method thereof. The device comprises a reaction furnace, a laser generating system, a target material supply system and a control system. The laser generating system adopts a low-cost and long-life optical fiber laser array to form a large-area irradiation area; the target material supply system continuously transports a graphite composite target material doped with a specific binary metal catalyst to the irradiation area through a linear track. Under an inert atmosphere and high temperature, the optical fiber laser array is used to evaporate the composite target material containing hafnium (Hf) and iron-based transition metals, carbon atoms are catalytically induced to self-assemble, and single-wall carbon nanometer tubes are continuously grown. Through the cooperation of the low-cost laser source, the hafnium-based catalyst and the continuous feeding system, the problems of expensive equipment, low yield, difficult tube diameter control and intermittent production of the traditional laser method are solved, and the low-cost, large-batch and continuous preparation of high-quality single-wall carbon nanometer tubes is realized.

Description

Technical Field

[0001] This invention belongs to the field of nanomaterial preparation technology, specifically relating to a single-walled carbon nanotube, its preparation apparatus and preparation method. Background Technology

[0002] Laser evaporation is one of the important methods for preparing high-purity, high-quality single-walled carbon nanotubes. The traditional process uses a high-energy-density pulsed laser (such as a Nd:YAG or CO2 laser) to bombard a graphite target containing a metal catalyst. Although this method can yield single-walled carbon nanotubes with excellent structures, the equipment is expensive, the yield is low, and it is an intermittent operation, making it difficult to scale up.

[0003] In pursuit of continuous production, various technologies have been explored. For example, patent document CN110217778A discloses an "apparatus and method for continuous preparation of high-quality carbon nanotubes." This technology combines electron beam evaporation with chemical vapor deposition (CVD). The core of the apparatus includes an electron beam evaporation device, a vacuum transition chamber, a gas / liquid injection device, a reactor, and a collection device. During operation, the electron beam evaporation device generates atomic-level metal catalyst particles, which are directly injected into the high-temperature reactor after vacuum transition. Simultaneously, a carrier gas and liquid carbon source are introduced. The carbon source is pyrolyzed and carbon nanotubes are catalytically grown through the CVD process, achieving continuous product collection. While this existing technology achieves continuous production through the continuous supply of catalyst and carbon source, its technical approach has significant limitations. First, this scheme integrates two complex systems: electron beam evaporation and CVD. The equipment structure is cumbersome, involving multiple high-precision aspects such as high vacuum, precise atmosphere control, and multi-feed, resulting in huge equipment investment, complex operation and maintenance, and high difficulty in process control. Secondly, its growth mechanism is essentially a CVD process, which differs from the classic laser evaporation method in terms of physicochemical environment and product characteristics. Most importantly, it uses a conventional transition metal catalyst system and lacks the design to actively constrain and stabilize the catalyst particle size during the reaction process, resulting in insufficient control over the diameter of the generated single-walled carbon nanotubes and difficulty in obtaining products with uniform diameter, especially small diameter.

[0004] Therefore, how to overcome the disadvantage of weak control over the product diameter (especially small diameter) while retaining the inherent advantage of high product quality of laser evaporation, and at the same time achieve low-cost, high-yield continuous preparation, has become an urgent problem to be solved in this field. Summary of the Invention

[0005] The objective of this invention is to provide a single-walled carbon nanotube based on the principle of laser evaporation, its preparation apparatus, and its preparation method, to address the insufficient control over the diameter (especially small diameter) of single-walled carbon nanotubes in existing laser evaporation methods and continuous production techniques. A further objective is to simultaneously solve the problems of low yield, high cost, and intermittent production associated with traditional laser methods, while achieving the aforementioned diameter control, thereby realizing the low-cost, high-volume, and continuous preparation of high-quality single-walled carbon nanotubes.

[0006] The technical solution of the present invention is as follows: On one hand, an apparatus for preparing single-walled carbon nanotubes is provided, comprising: The reactor has a reaction chamber inside; A laser generating system includes a fiber laser array composed of multiple fiber lasers and a beam combining optical element. The beam combining optical element is used to combine the multiple laser beams emitted by the fiber laser array and form an irradiation area with a diameter of 20-50 mm in the reaction chamber. A target supply system includes a linear track and a plurality of targets disposed on the linear track. The targets are graphite composite targets containing metal catalysts. The linear track is configured to deliver the targets sequentially and continuously to the irradiation area. The system includes a control system electrically connected to the laser generating system and the target supply system, used to control the laser's on / off state and power, as well as the target's feed speed.

[0007] Preferably, the metal catalyst in the target material comprises hafnium (Hf) and at least one iron-based transition metal element selected from iron (Fe), nickel (Ni), and cobalt (Co).

[0008] Preferably, the target material supply system further includes a stepper motor for driving the linear track motion, and the target material feed speed is 0.05~1.0 mm·s. -1 .

[0009] Preferably, the reactor is provided with an inlet for introducing inert gas and an outlet for connecting to a collector.

[0010] On the other hand, a method for preparing single-walled carbon nanotubes using the above-described apparatus is provided, comprising the following steps: S1. A graphite composite target doped with a metal catalyst is provided, wherein the metal catalyst comprises hafnium (Hf) and at least one iron-based transition metal element selected from iron (Fe), nickel (Ni), and cobalt (Co); S2. In an inert gas atmosphere and at a reaction temperature of 1000~1300℃, the target material is irradiated by an irradiation area generated and combined by a fiber laser array, so that the target material evaporates and catalyzes the growth of single-walled carbon nanotubes. The target material is positioned on a linear track at a speed of 0.05~1.0 mm·s. -1 The feed rate is continuously increased to the irradiation area to achieve continuous growth and collection of single-walled carbon nanotubes.

[0011] Preferably, in the metal catalyst, the molar ratio of hafnium (Hf) to the iron-based transition metal element is (0.2~5):1.

[0012] Preferably, the total mass percentage of the metal catalyst in the target material is 1-15 wt%; and the total laser power generated by the fiber laser array is 5-60 kW.

[0013] Preferably, the inert gas is one or more of argon, nitrogen, or helium, and the reaction environment pressure is maintained at 20~100kPa.

[0014] Finally, a single-walled carbon nanotube is provided, which is prepared by the method described in any of the above-mentioned methods.

[0015] Compared with the prior art, the advantages of the present invention are: (1) The use of fiber laser arrays with lower cost, longer life and easier maintenance to replace expensive traditional high-energy pulsed lasers significantly reduces the initial investment and operating costs of the equipment. At the same time, multiple laser beams are combined to form a large area of ​​irradiation. Combined with continuously fed target materials, the amount of raw material evaporation and carbon nanotube generation per unit time is greatly improved, achieving high yield.

[0016] (2) By using a linear orbit to continuously feed multiple target units, the disadvantage of the traditional laser method requiring frequent shutdowns to replace the target is overcome. The device can run for tens of hours at a time, realizing uninterrupted, stable, and large-scale preparation of single-walled carbon nanotubes, and has the potential for industrial production.

[0017] (3) By introducing binary composite catalyst systems such as Hf-Fe / Ni / Co, and utilizing the high melting point and low carbon solubility of Hf, the Hf phase can effectively divide and anchor the active phase regions of iron system (Fe, Ni, Co) in the high-temperature catalyst droplets formed by laser evaporation, inhibiting their Ostwald ripening and agglomeration at high temperature, thereby limiting the size of the catalyst active species to the nanoscale, creating conditions for the growth of small-diameter single-walled carbon nanotubes, and improving the quality of the product in terms of tube diameter uniformity.

[0018] (4) By optimizing and integrating the core elements of laser evaporation process (energy input, material transport, and reaction environment) and using controllable components such as fiber laser array and linear feed, the controllability and stability of the process are improved, which helps to achieve consistency in product quality and stable operation of the production process. Attached Figure Description

[0019] The present invention will be further described below with reference to the accompanying drawings and embodiments: Figure 1 This is a schematic diagram of an apparatus for preparing carbon nanotubes by laser method according to the present invention; Figure 2 This is a scanning electron microscope image of single-walled carbon nanotubes in the initial powder prepared in Example 1 of the present invention; Figure 3 The Raman spectrum of the single-walled carbon nanotubes prepared in Example 1 of this invention; Figure 4 The thermogravimetric curve of the initial sample prepared in Example 1 of the present invention.

[0020] The components include: 1. Reactor; 2. Target material; 3. Collector; 4. Linear track; 5. Inert gas; 6. Fiber laser array. Detailed Implementation

[0021] The present invention will be further described in detail below with reference to specific embodiments: like Figure 1 The diagram illustrates the apparatus structure of a preferred embodiment of the present invention. The single-walled carbon nanotube fabrication apparatus mainly includes a reactor 1, a laser generation system, a target material supply system, and a control system.

[0022] Reactor 1 is a tubular resistance furnace, its core being a horizontally or slightly inclined high-temperature resistant alumina ceramic tube forming the reaction chamber. Heating wires are wound around the outside of the furnace tube, and a temperature controller precisely controls the temperature distribution within the furnace, ensuring that the central region (i.e., the reaction zone) reaches and stabilizes at the set temperature. One end of the furnace tube has an inlet for introducing inert gas 5 (such as argon), and the other end has an outlet connected to the product collector 3. The furnace pressure can be controlled by adjusting the inlet flow rate and the outlet back pressure valve.

[0023] The core of the laser generation system is the fiber laser array 6. In this embodiment, the fiber laser array 6 consists of eight continuous fiber laser modules with an output wavelength of 1070nm arranged in a ring. The eight laser beams are collimated and combined through a shared beam-combining lens group, and finally enter through a quartz window on the side of the reactor 1, converging in the reaction zone at the center of the furnace tube to form a uniform circular spot with a diameter of approximately 30mm, i.e., the irradiation area. The rated power of each fiber laser can be selected as needed, for example, 3~10kW, and the total system power can be flexibly adjusted.

[0024] The target material supply system includes a precision linear guide rail, namely linear track 4, and target materials 2 placed on it, which are multiple cylindrical graphite composite materials. The preparation method of target material 2 is as follows: high-purity graphite powder (>99.9%), nickel powder (>99.5%), and hafnium powder (>99.5%) are weighed according to a designed molar ratio, for example, C:Ni:Hf=92:2.4:5.6. The powders are thoroughly mixed in a three-dimensional mixer for a long time (e.g., 24 hours or more) to ensure uniformity. Then, the mixed powder is loaded into a specific mold and cold-pressed into a dense cylindrical blank under a hydraulic press at a pressure of 200~300MPa. Finally, the blank is sintered at 1200~1400℃ for 1~3 hours under argon protection to improve its mechanical strength and density, obtaining the final target material 2. Multiple target materials 2 are arranged end-to-end on the linear track 4. The linear track 4 is driven by a high-precision stepper motor and ball screw, which can smoothly push the entire row of targets 2 into the reactor 1 at a constant speed adjustable in the range of 0.05~1.0mm / s, ensuring that the targets 2 currently in the irradiation area are continuously evaporated and consumed, while subsequent targets 2 can be replenished in time.

[0025] Collector 3 is typically connected downstream of the gas outlet of reactor 1 and can be a simple cold trap, a cloth bag, or a chamber with a filter device, used to capture and enrich the carbon nanotube products that drift out with the gas flow.

[0026] The control system is integrated into an industrial control cabinet, comprising a laser power supply control module, a stepper motor drive module, a temperature control module, and a pressure monitoring module. It receives feedback signals from various sensors and coordinates the operation of the entire device according to a preset program.

[0027] The preparation method and technical effects of the present invention will be described in detail below through specific embodiments and comparative examples.

[0028] Example 1

[0029] This embodiment details the entire process of preparing single-walled carbon nanotubes using the apparatus and method of the present invention.

[0030] Preparation of Target Material 2: The raw materials were accurately weighed to achieve a molar ratio of graphite (C), nickel (Ni), and hafnium (Hf) of 92:2.4:5.6. After mixing, cold pressing, and high-temperature sintering, several dense composite target cylinders with a diameter of 30 mm and a length of 200 mm were obtained. The total mass percentage of the metal catalyst (Ni+Hf) was calculated to be approximately 8.5 wt%.

[0031] Device loading and preparation: Load the prepared target materials 2 sequentially onto the linear track 4. Seal the reactor 1 and check its airtightness.

[0032] Establishing the reaction environment: Start the heating program of reactor 1, and precisely control the temperature of the reaction zone at the center of the furnace tubes at 1200℃ using the temperature control system. Inert gas 5 (such as high-purity argon) is introduced into the furnace at a constant flow rate using a mass flow controller, and the working pressure inside the furnace is stabilized at 40 kPa by adjusting the outlet valve. This step provides the necessary high-temperature, inert, and low-pressure environment for carbon nanotube growth.

[0033] Initiating continuous feeding and laser irradiation: First, the target supply system is started. The control system instructs a stepper motor to drive linear track 4, pushing the target array into the furnace at a constant speed of 0.2 mm / s. When the end of the first target 2 reaches the center of the irradiation area, the fiber laser array 6 is activated. In this embodiment, the total output power of the eight fiber lasers is set to 30 kW. After beam combining, a uniform circular spot with a diameter of approximately 30 mm is formed in the reaction zone, with a power density of approximately 4.2 × 10⁻⁶. 4 W / cm². At this time, the device operates as follows: the reactor 1 provides the environment, the fiber laser array 6 provides energy and forms the irradiation area, and the target 2 is continuously fed into the irradiation area on the linear track 4.

[0034] Growth Process and Mechanism: A high-power-density laser instantly heats the surface of target material 2 within the irradiation area to above the evaporation temperature, generating a high-temperature gaseous product containing C atoms, Ni atoms, Hf atoms, and their clusters. The key catalytic growth mechanism occurs here: in a high-temperature inert atmosphere, the evaporated Ni and Hf atoms rapidly condense into nanoscale alloy droplets. Due to the extremely high melting point of Hf and the extremely low solubility of carbon within it, it acts as a "structural stabilizer" in this composite droplet. On one hand, the presence of the Hf phase physically segments and anchors the Ni-rich active phase region, effectively inhibiting the migration and aggregation of Ni nanoparticles at high temperatures, limiting their size to a small range (e.g., 1-2 nm). On the other hand, Ni has high solubility for carbon. C atoms captured from the plasma rapidly dissolve into these size-constrained Ni regions. When the carbon concentration reaches supersaturation, carbon atoms precipitate from the catalyst particle surface in the form of a graphite network. Due to the small and uniform size of the catalyst particles, the single-walled carbon nanotubes formed by the curling of the precipitated graphite sheets also possess small and uniform diameters.

[0035] Continuous operation and product collection: The above growth process continues. Target 2 is continuously consumed under laser irradiation, while linear orbital 4 continuously replenishes subsequent target 2s, achieving continuous material supply and continuous reaction. The carbon nanotubes and soot produced during growth flow downstream of the furnace tube with the argon gas flow, eventually entering and depositing in collector 3. This embodiment operates continuously and stably for 10 hours.

[0036] Product collection and characterization: After the operation was completed, the system was cooled and a black fluffy powder product of about 16g was obtained from collector 3.

[0037] Product analysis and demonstration: like Figure 2 Morphology and structure shown: Scanning electron microscopy (SEM) images show that the product has a typical nanofiber network structure with fine and uniform fiber diameter.

[0038] like Figure 3 The Raman spectrum shown reveals three characteristic regions of single-walled carbon nanotubes: located at 150–300 cm⁻¹. -1 The radial breathing mode (RBM) peak group indicates that the product is a single-walled carbon nanotube, and the estimated diameter of the tubes, based on the peak position, is mainly distributed in the range of 1.2–1.5 nm; located at ~1590 cm⁻¹. -1 The strong G peak (characteristic of graphitic carbon) and located at ~1350 cm⁻¹ -1 The weak D peak (defect characteristic) and the G / D intensity ratio greater than 50 indicate that the product has a high degree of graphitization, few crystallization defects, and excellent quality.

[0039] like Figure 4 Thermogravimetric analysis (TGA) shown: Under air atmosphere, the TGA curves indicate that the sample begins to lose weight through oxidation at approximately 550°C, and the oxidation is almost complete by approximately 650°C, indicating high purity of the carbon nanotubes. The peak oxidation temperature of around 600°C also confirms its good thermal stability. The final residue (mainly metal oxides) has a mass fraction of less than 5 wt%, further confirming the high purity of the product.

[0040] Conclusion: This embodiment successfully obtained high-quality, small-diameter single-walled carbon nanotubes with a yield of 1.6 g / h, verifying the beneficial effects of the device and method of the present invention.

[0041] Example 2

[0042] This example aims to illustrate the effect of catalyst ratio on experimental results.

[0043] By changing the catalyst ratio in target material 2, a target material 2 with a C:Ni:Hf molar ratio of 94:4.5:1.5 was prepared. At this time, the Hf:Ni molar ratio was approximately 1:3.

[0044] The apparatus was run for 10 hours with the exact same setup, reaction conditions (1200°C, 40 kPa Ar) and process parameters (feed rate 0.2 mm / s, total laser power 30 kW) as in Example 1.

[0045] Results and Comparative Analysis: Approximately 15.5 g of product was obtained. Raman spectroscopy showed the presence of RBM peaks, with a G / D ratio of approximately 45, indicating successful preparation of single-walled carbon nanotubes, although the G / D ratio was slightly lower than that of Example 1. Transmission electron microscopy (TEM) observation showed that the tube diameter distribution was slightly wider than that of Example 1 (approximately 1.2–1.8 nm).

[0046] Reaction mechanism analysis: At this ratio, the Hf content is relatively low, which weakens its effect on the size confinement of Ni catalyst particles, resulting in a slightly wider catalyst particle size distribution. Consequently, the diameter distribution of the grown single-walled carbon nanotubes also becomes wider (approximately 1.2~1.8 nm). This indicates that by adjusting the ratio of Hf to iron-based metals, the catalyst particle size can be controlled, thereby influencing and regulating the diameter distribution of the final product.

[0047] Comparative Example 1 Device Simulation: A simplified system combining electron beam evaporation and tubular CVD was constructed. A nickel sheet was placed in the electron beam evaporation source, and the evaporated Ni atoms were introduced into the center of a horizontal tube furnace (temperature 1200℃) through a vacuum transition chamber. Argon (1L / min) and hydrogen (1L / min) were simultaneously introduced from upstream as carrier gases, and ethanol (20ml / h) was injected as the carbon source via a syringe pump.

[0048] Process: The electron beam evaporator is started, continuously injecting Ni atoms into the high-temperature furnace zone; simultaneously, ethanol is decomposed at high temperature. The goal is to grow carbon nanotubes on the Ni catalyst via a CVD process.

[0049] Results and Comparison: After 5 hours of operation, a small amount of black material, approximately 1.2 g, was collected downstream of the furnace tube. SEM analysis of the product showed the presence of carbon nanotubes, but also a large amount of amorphous carbon. The Raman spectroscopy G / D ratio was only about 15. Analysis: This comparative example simulates the core process of CN110217778A. Its equipment is complex (requiring vacuum, evaporation, and multi-channel gas intake control), but the yield is low (0.24 g / h). More importantly, the process of catalyst (Ni atoms) condensation, migration, and growth after entering the reaction zone is difficult to control precisely, and the matching of carbon source cracking and catalyst supply is complex, resulting in a product quality (crystallinity, purity) significantly lower than that of the laser evaporation method of this invention (Example 1). This demonstrates that this invention, by employing a simplified device (fiber laser array replacing a complex electron beam system) and an integrated target design, achieves a higher yield while ensuring or even improving product quality.

[0050] Comparative Example 2 Target material 2, containing only Ni as a catalyst, was prepared with a C:Ni molar ratio of 95:5 (the total metal content was comparable to that in Example 1).

[0051] The device was run for 10 hours using the exact same apparatus as in Example 1 (including fiber laser array 6 and linear track 4, etc.) and the exact same process parameters (temperature, pressure, feed rate, laser power).

[0052] Results and Mechanism Comparison Analysis: Approximately 17 g of product was obtained, with a yield comparable to that of Example 1. However, Raman spectroscopy showed a broader RBM peak and a decrease in the G / D ratio to approximately 35. High-resolution TEM observation revealed that although the product was mainly composed of single-walled carbon nanotubes, the diameter distribution range was significantly wider (0.9–2.2 nm), and a small number of double-walled nanotubes were also observed.

[0053] Reaction mechanism analysis: In the absence of Hf, pure Ni nanodroplets generated by laser evaporation are more prone to agglomeration and growth at high temperatures, leading to a wider size distribution of the catalyst particles. Larger catalyst particles may grow into single-walled tubes with larger diameters, and may even induce the nucleation of a second graphite layer, forming double-walled tubes. Smaller catalyst particles, on the other hand, grow into single-walled tubes with smaller diameters. The final product has a wide diameter distribution and poor uniformity. This comparison demonstrates the key "size confinement" role of Hf in the binary catalyst system, and it is this role that enables the present invention (Example 1) to obtain single-walled carbon nanotubes with more uniform and finer diameters.

[0054] A comparison of Comparative Example 2 and Example 1 shows that, without changing any other conditions (such as equipment, power, temperature, and feed rate), simply introducing hafnium (Hf) into the catalyst system described in this invention can significantly improve the uniformity of the product diameter, effectively narrow the diameter distribution (from 0.9~2.2 nm to 1.2~1.5 nm), and suppress the formation of double-walled carbon nanotubes. This indicates that, compared to existing technologies that simply pursue continuous production, and traditional hafnium-free catalyst laser evaporation methods, the hafnium-based binary catalyst system of this invention can solve the problem of single-walled carbon nanotube diameter control.

[0055] The results of the combined embodiments and comparative examples demonstrate that the technical solution provided by this invention effectively addresses the multiple problems pointed out in the background art: Compared with Comparative Example 1, which uses a simulated electron beam-CVD coupling technology, this invention significantly simplifies equipment and reduces potential costs while achieving higher yields (1.6 g / h in Example 1 and 0.24 g / h in Comparative Example 1) and better product quality (higher G / D ratio); compared with Comparative Example 2, which uses a traditional laser method without a hafnium catalyst, this invention maintains high yields while significantly improving the uniformity of product tube diameter by introducing hafnium (Hf), effectively suppressing wide tube diameter distribution and the formation of double-walled tubes. All these conclusions indicate that this invention synergistically solves long-standing problems in terms of high quality, low cost, high yield, continuous operation, and controllable tube diameter, achieving significant technical effects.

[0056] The above embodiments are merely illustrative of the technical concept and features of the present invention, intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly, and should not be construed as limiting the scope of protection of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects. The scope of the present invention is defined by the appended claims rather than the foregoing description, and thus all changes falling within the meaning and scope of the equivalents of the claims are intended to be included within the present invention.

Claims

1. An apparatus for preparing single-walled carbon nanotubes, comprising: The reactor has a reaction chamber inside; A laser generating system includes a fiber laser array composed of multiple fiber lasers and a beam combining optical element. The beam combining optical element is used to combine the multiple laser beams emitted by the fiber laser array and form an irradiation area with a diameter of 20-50 mm in the reaction chamber. A target supply system includes a linear track and a plurality of targets disposed on the linear track. The targets are graphite composite targets containing metal catalysts. The linear track is configured to deliver the targets sequentially and continuously to the irradiation area. The system includes a control system electrically connected to the laser generating system and the target supply system, used to control the laser's on / off state and power, as well as the target's feed speed.

2. The apparatus for preparing single-walled carbon nanotubes according to claim 1, characterized in that, The metal catalyst in the target material comprises hafnium (Hf) and at least one iron-based transition metal element selected from iron (Fe), nickel (Ni), and cobalt (Co).

3. The apparatus for preparing single-walled carbon nanotubes according to claim 1, characterized in that, The target material supply system also includes a stepper motor that drives the linear track motion, and the target material feed speed is 0.05~1.0 mm·s. -1 .

4. The apparatus for preparing single-walled carbon nanotubes according to claim 1, characterized in that, The reactor is equipped with an inlet for introducing inert gas and an outlet for connecting to a collector.

5. A method for preparing single-walled carbon nanotubes using the apparatus according to any one of claims 1-4, comprising the following steps: S1. Provides a graphite composite target material doped with a metal catalyst, wherein the metal catalyst comprises hafnium (Hf) and at least one iron-based transition metal element selected from iron (Fe), nickel (Ni), and cobalt (Co); S2. In an inert gas atmosphere and at a reaction temperature of 1000~1300℃, the target material is irradiated by an irradiation area generated and combined by a fiber laser array, so that the target material evaporates and catalyzes the growth of single-walled carbon nanotubes. The target material is positioned on a linear track at a speed of 0.05~1.0 mm·s. -1 The feed rate is continuously increased to the irradiation area to achieve continuous growth and collection of single-walled carbon nanotubes.

6. The method for preparing single-walled carbon nanotubes according to claim 5, characterized in that, In the metal catalyst, the molar ratio of hafnium (Hf) to the iron-based transition metal element is (0.2~5):

1.

7. The method for preparing single-walled carbon nanotubes according to claim 5, characterized in that, The total mass percentage of the metal catalyst in the target material is 1-15 wt%; the total laser power generated by the fiber laser array is 5-60 kW.

8. The method for preparing single-walled carbon nanotubes according to claim 5, characterized in that, The inert gas is one or more of argon, nitrogen, or helium, and the reaction environment pressure is maintained at 20~100kPa.

9. A single-walled carbon nanotube, characterized in that, The single-walled carbon nanotubes are prepared by the method described in any one of claims 5 to 8.

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