Supported catalyst for synthesizing single-walled carbon nanotubes as well as preparation method and application of supported catalyst

Abstract

The invention provides a supported catalyst for synthesizing a single-walled carbon nanotube as well as a preparation method and application of the supported catalyst. The supported catalyst for synthesizing the single-walled carbon nanotube is prepared by the preparation method. The preparation method comprises the following steps: pretreating a carrier precursor to obtain a solution A; dissolving a metal active component in water to obtain a solution B; mixing the solution A and the solution B to obtain a solution C; adding a metal complexing agent into the solution C, heating and stirring to obtain a uniformly mixed solution, and continuously heating to evaporate water to obtain gel; drying the gel to obtain a porous material, grinding the porous material into powder, and performing first roasting to obtain a catalyst precursor; cooling the catalyst precursor, then carrying out second roasting, and cooling; the carrier precursor is a metal salt or a coupling substance of the metal salt; the metal salt comprises silicon salt, aluminum salt, zirconium salt and magnesium salt; the metal active component is selected from iron, cobalt, tungsten, molybdenum and nickel. The single-walled carbon nanotube with better comprehensive performance can be prepared by using the supported catalyst through a chemical vapor deposition method.

Description

Technical Field

[0001] This invention belongs to the field of carbon nanotube preparation and catalyst technology, and particularly relates to a supported catalyst for synthesizing single-walled carbon nanotubes, its preparation method and application. Background Technology

[0002] Single-walled carbon nanotubes (SUVs) can be considered as geometric structures formed by rolling up a single layer of graphene. Due to the all-carbon-carbon covalent bond characteristic of their structure, they exhibit excellent thermodynamic and electrical properties, and have enormous application potential in many fields such as new energy vehicles, energy storage batteries, nanoelectronic devices, composite materials, and catalyst supports. They are regarded as a universal industrial additive. With the rapid development of related industries, the demand for SUVs has increased significantly.

[0003] Currently, the main methods for preparing single-walled carbon nanotubes (SUVs) include chemical vapor deposition (CVD), laser evaporation, and plasma-arc deposition. SUVs require a suitable catalyst. Furthermore, traditional metal catalysts such as Fe, Ni, Co, and related alloys, due to their moderate melting points, inevitably aggregate and deactivate at high temperatures, limiting the quality and yield of SUVs at high temperatures. While some high-melting-point metals can be used as catalysts, they present challenges such as complex preparation processes, demanding equipment requirements, low reproducibility, difficulty in removing metallic impurities, and the potential for affecting the physical properties of SUVs.

[0004] Therefore, developing a catalyst that can adapt to high-temperature reaction conditions, has high catalytic activity and stability, and can improve the yield and quality of single-walled carbon nanotubes is of great practical significance.

[0005] In view of this, the present invention is hereby proposed. Summary of the Invention

[0006] The purpose of this invention is to provide a supported catalyst for the synthesis of single-walled carbon nanotubes, its preparation method, and its application, in order to solve the above-mentioned problems.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: This invention first provides a method for preparing a supported catalyst for synthesizing single-walled carbon nanotubes, the method comprising the following steps: S1: Pretreatment of the carrier precursor yields carrier solution A; S2: Dissolve the active metal component in water to obtain solution B; S3: Solution A and solution B are mixed under heating and stirring conditions to obtain solution C; S4: Add the metal complexing agent to solution C, heat and stir continuously to obtain a homogeneous solution, continue heating to evaporate the water, and obtain a gel; S5: The gel obtained in S4 is dried to obtain a porous material, which is then ground into powder and calcined in an inert atmosphere to obtain a catalyst precursor. S6: The catalyst precursor obtained in S5 is first cooled to room temperature, then calcined in air atmosphere, and then cooled to obtain the supported catalyst for the synthesis of single-walled carbon nanotubes. In step S1, the carrier precursor is a metal salt or a coupling product of a metal salt; The metal salts include silicon salts, aluminum salts, zirconium salts, and magnesium salts; preferably, the silicon salts include sodium silicate; the aluminum salts include aluminum hydroxide, aluminum nitrate, and aluminum isopropoxide; the zirconium salts include zirconium oxychloride and zirconium nitrate; and the magnesium salts include magnesium nitrate. More preferably, when the carrier precursor is composed of silicon salt, aluminum salt and zirconium salt, the molar ratio of the metal elements silicon, aluminum and zirconium is 0-0.2:0-0.2:1; The active metal component is selected from one or more of iron, cobalt, tungsten, molybdenum, and nickel; preferably, the active component includes molybdenum and iron; more preferably, the molar ratio of molybdenum to iron is 0.01-0.5:1.

[0008] Optionally, in step S1, the pretreatment includes: preparing a silicate colloidal solution A-1 from silicate salts, dissolving aluminum salts and / or zirconium salts in water to obtain solution A-2, preparing an Al2O3-ZrO2 composite solution from solution A-2 using a homogeneous precipitation method; adding the Al2O3-ZrO2 composite solution to the silicate colloidal solution A-1 under heat preservation and stirring conditions and mixing thoroughly to obtain the carrier solution A.

[0009] Preferably, in step S3, the mixing is carried out in a rotary evaporator, the rotary evaporator rotating at a speed of 50–500 rpm / min; and the mixing temperature is 50–90°C. Preferably, the pH of solution A is adjusted to 7-10 before mixing; More preferably, the pH of solution A is adjusted to 8-10 before mixing.

[0010] More preferably, the mixing includes: adding solution A to solution B under heating and stirring conditions to obtain solution C; Alternatively, solution B can be added to solution A under heating and stirring conditions to obtain solution C.

[0011] Preferably, when the pretreatment is as follows: preparing a silicate colloidal solution A-1 from silicate, dissolving aluminum salt and / or zirconium salt in water to obtain solution A-2, and preparing an Al2O3-ZrO2 composite solution from solution A-2 by homogeneous precipitation; adding the Al2O3-ZrO2 composite solution to silicate colloidal solution A-1 under heat preservation and stirring conditions and mixing thoroughly to obtain the carrier solution A, before mixing, the pH value of solution A-1 is adjusted to 2-4 and the pH value of solution A-2 is adjusted to 9-11 respectively; adjusting the pH value of solution A-1 to 2-4 promotes colloid formation, and then mixing it with A-2, so that the pH of the mixed solution is between 7-10, which can accelerate the gelation process.

[0012] Optionally, the preparation method further satisfies one or more of the following conditions: a. In step S4, the metal complexing agent includes one or more of citric acid, tartaric acid, oxalic acid, acetic acid, and formic acid; b. In step S5, the drying process is carried out at a temperature of 100-160°C for 6-10 hours. c. In step S5, the particle size of the powder is 5-40 μm; The particle size of the powder is preferably 20-30 μm; d. In step S5, the temperature of the first calcination is 400-1000℃, and the time is 1-5h; e. In step S6, the temperature of the second calcination is 400-800℃ and the time is 1-10h; The preferred temperature for the second roasting is 600-700℃.

[0013] The present invention also provides a supported catalyst for the synthesis of single-walled carbon nanotubes, which is prepared by the aforementioned preparation method; The supported catalyst is composed of a support and an active component, wherein the total mass of the active component is 2-10% of the mass of the support.

[0014] A third aspect of the present invention provides an application of a supported catalyst prepared by the aforementioned method for synthesizing single-walled carbon nanotubes, wherein the step of preparing single-walled carbon nanotubes using the supported catalyst via chemical vapor deposition includes: After the carrier gas is introduced into the fluidized bed reactor, the fluidized bed reactor is heated to 600-800°C, the supported catalyst is added, and the reducing gas is added evenly. After reacting for 10-60 minutes, the raw material gas is added, and the reaction is completed, resulting in a black fluffy solid. Then, after purification, acid washing, and water washing, single-walled carbon nanotubes are obtained. The carrier gas includes any one of nitrogen, helium, and argon; The reducing gas is hydrogen; The raw material gas includes one or more of methane, ethane, ethylene, propane, butane, and propylene.

[0015] Unlike conventional catalyst preparation methods, this invention uses one or more of the following as precursors to prepare a supported catalyst: zirconium oxychloride, zirconium nitrate, magnesium nitrate, aluminum hydroxide, aluminum nitrate, aluminum isopropoxide, and sodium silicate. During the precursor preparation process, precursors are prepared separately according to molar ratios, and then the prepared precursors are mixed to obtain a composite support. During the precursor mixing process, the Al₂O₃-ZrO₂ composite solution is slowly added to the silica colloid solution under stirring during the 1-2 hour condensation process of silica colloid. When the pH is > 2, the silica colloid prevents the Al₂O₃-ZrO₂ composite particles from agglomerating through electrostatic repulsion. When the pH is adjusted to 8-10, the negative charge density of the silica colloid increases, thereby improving the dispersibility of the Al₂O₃-ZrO₂ composite and making the composite support more stable.

[0016] The beneficial effects of this invention are: The method for preparing the supported catalyst provided by this invention differs from conventional supported catalyst supports. By precisely controlling the composition of the composite support through molar ratio and adjusting the surface acidity and alkalinity of the support, the performance of the support is effectively improved. Combined with rotary evaporation coating, the dispersion of active components is improved, thereby effectively improving the structure and catalytic performance of the catalyst. The resulting catalyst can significantly improve the growth rate of carbon nanotubes when used for the growth of single-walled carbon nanotubes.

[0017] The active metal component and support structure of the catalyst provided by this invention can be precisely controlled.

[0018] The diameter of single-walled carbon nanotubes prepared using the supported catalyst provided by this invention can be controlled at 1-5 nm, the tube length at 5-50 μm, the powder resistivity can be as low as 0.8 Ω·cm, and the growth rate is 15-20 times. Attached Figure Description

[0019] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0020] Figure 1 The image shows the morphology of the carbon nanotubes provided in Example 1. Figure 2 The image shows the morphology of the carbon nanotubes provided in Example 2. Figure 3 The image shows the morphology of the carbon nanotubes provided in Example 3; Figure 4 The image shows the morphology of the carbon nanotubes provided in Example 4; Figure 5 The morphological image of the carbon nanotubes provided for Comparative Example 1; Figure 6 The morphological image of the carbon nanotubes provided for Comparative Example 2; Figure 7 The morphological image of the carbon nanotubes provided for Comparative Example 3; Figure 8 The image shows the morphology of the carbon nanotubes provided for Comparative Example 4. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] Example 1 This embodiment first provides a method for preparing a supported catalyst for the growth of single-walled carbon nanotubes, the specific steps of which are as follows: S1: According to the molar ratio of silicon:aluminum:zirconium metal elements of 0.1:0.1:1, take 12.2g of sodium silicate, 21.3g of aluminum nitrate, and 17.8g of zirconium oxychloride. Prepare a silicate colloidal solution A-1 with sodium silicate and adjust the pH of solution A-1 to 2-4. Dissolve aluminum nitrate and zirconium oxychloride in water to prepare solution A-2. Adjust the pH of solution A-2 to 9-10. Then, prepare an Al2O3-ZrO2 composite solution by homogeneous precipitation. Slowly add the silicate colloidal solution A-1 to the Al2O3-ZrO2 composite solution under stirring at 50-80℃ and mix thoroughly to obtain SiO2-Al2O3-ZrO2 carrier solution A.

[0023] S2: Take 3.078g of active component according to the molar ratio of molybdenum to iron of 0.23:1, that is, take 9.33g of ferric nitrate and 1.89g of ammonium molybdate; dissolve ferric nitrate and ammonium molybdate in water to obtain solution B.

[0024] S3: Adjust the pH of solution A to 8 in a rotary evaporator, and slowly add solution B to solution A under heating and stirring conditions to obtain solution C; control the mixing temperature at 90℃; control the stirring speed at 500 rpm / min.

[0025] S4: Take 13.89g of citric acid, a metal complexing agent, and slowly add it to solution C. Keep heating and stirring to obtain a uniformly mixed solution. Continue heating to evaporate the water and obtain a gel.

[0026] S5: The gel obtained in S4 was placed in an oven at 100°C and kept for 6 hours to obtain a porous material. The porous material was then ground into a 20-30 μm powder and calcined in nitrogen at 600°C for 2 hours to obtain a catalyst precursor with a stable structure.

[0027] S6: After the catalyst precursor obtained in S5 is cooled to room temperature, it is placed in air and calcined at 700°C for 5 hours, and then cooled to room temperature to obtain the supported catalyst.

[0028] S7: Single-walled carbon nanotubes were prepared using the supported catalyst obtained in S6. The specific steps are as follows: After nitrogen carrier gas is introduced into the fluidized bed reactor, the temperature of the fluidized bed reactor is slowly raised to 800°C. The catalyst obtained from S6 is added, and hydrogen reducing gas is added evenly. After reacting for 15 minutes, methane feed gas is added. The reaction is completed, and a black, fluffy solid is obtained. Then, it is purified, acid-washed, and water-washed in sequence to obtain single-walled carbon nanotubes. The ratio of the obtained single-walled carbon nanotubes is 20 times.

[0029] The morphology of the single-walled carbon nanotubes obtained in this embodiment is shown in the figure below. Figure 1 As shown, by Figure 1 It can be seen that the prepared single-walled carbon nanotubes have uniform diameter and a large aspect ratio.

[0030] Example 2 The difference from Example 1 is that in this example, step S3 involves adding solution A to solution B to obtain solution C. Therefore, step S3 in this example is: S3: Adjust the pH of solution A to 8, and then slowly add it to solution B under heating and stirring conditions to obtain solution C. The mixing process is carried out in a rotary evaporator reactor; the mixing temperature is controlled at 90℃; and the stirring speed is controlled at 500 rpm / min.

[0031] The remaining steps are the same as in Example 1.

[0032] The morphology of single-walled carbon nanotubes prepared using the catalyst obtained in this embodiment is shown in the figure below. Figure 2 As shown, by Figure 2 It can be seen that the single-walled carbon nanotubes prepared in this embodiment exhibit cross-linking.

[0033] Example 3 The difference from Example 1 is that the carrier precursor used to prepare carrier solution A in this example does not include silicon salt, that is, S1 in this example is: S1: According to the molar ratio of aluminum to zirconium metal elements of 0.1:1, take 21.3g of aluminum nitrate and 17.8g of zirconium oxychloride; dissolve aluminum nitrate and zirconium oxychloride in water and prepare Al2O3-ZrO2 composite, i.e., carrier solution A, by uniform precipitation method.

[0034] The remaining steps are the same as in Example 1.

[0035] The morphology of the carbon nanotubes prepared by the catalyst in this embodiment is shown in the figure below. Figure 3 As shown, by Figure 3 It can be seen that the produced single-walled carbon nanotubes have acceptable morphology, but at the same time, oligo-walled carbon nanotubes are also generated.

[0036] Example 4 The difference from Example 1 is that the carrier precursor used to prepare carrier solution A in this example does not include aluminum salt, that is, S1 in this example is: S1: According to the molar ratio of silicon to zirconium metal elements of 0.1:1, take 12.2g of sodium silicate and 17.8g of zirconium oxychloride; prepare a silicate colloidal solution A-1 from sodium silicate; dissolve zirconium oxychloride in water and hydrolyze it to obtain solution A-2; slowly add solution A-2 to silicate colloidal solution A-1 under the condition of keeping warm and stirring, and mix thoroughly to obtain SiO2-ZrO2 carrier solution A.

[0037] The remaining steps are the same as in Example 1.

[0038] The morphology of carbon nanotubes prepared using the catalyst provided in this embodiment is shown in the figure below. Figure 4 As shown, by Figure 4 It can be seen that the carbon nanotubes obtained in this embodiment are not single-walled carbon nanotubes, and the outer wall of the obtained carbon nanotubes is irregular.

[0039] Comparative Example 1 The difference from Example 1 is as follows: S1: According to the molar ratio of silicon:aluminum:zirconium metal elements of 0:0:1, take 17.8g of zirconium oxychloride; dissolve it in water to make a solution, and then hydrolyze it to obtain nano-sized ZrO2, which is used as carrier solution A.

[0040] The remaining steps are the same as in Example 1.

[0041] The morphology of carbon nanotubes prepared using the catalyst provided in this comparative example is shown in the figure below. Figure 5 As shown, by Figure 5 It can be seen that this comparative example can obtain single-walled carbon nanotubes, but the obtained carbon nanotubes are not pure, and contain a relatively disordered mixture of carbon nanotubes with a large amount of impurities.

[0042] Comparative Example 2 The difference from Example 1 is as follows: In S1, the molar ratio of silicon:aluminum:zirconium metal elements is 0.5:0.5:1, and the remaining steps are the same as in Example 1.

[0043] The morphology of carbon nanotubes prepared using the catalyst provided in this comparative example is shown in the figure below. Figure 6 As shown, by Figure 6 It can be seen that the carbon nanotubes prepared in this comparative example are relatively disordered and tend to be large-diameter single-walled carbon nanotubes.

[0044] Comparative Example 3 The difference from Example 1 is as follows: In S1, the molar ratio of silicon:aluminum:zirconium metal elements is 1:1:1, and the remaining steps are the same as in Example 1.

[0045] The morphology of carbon nanotubes prepared using the catalyst provided in this comparative example is shown in the figure below. Figure 7 As shown, by Figure 7 It can be seen that the carbon nanotubes prepared in this comparative example are close to large-diameter single-walled carbon nanotubes, and there is an interlacing phenomenon, as well as a large amount of impurities.

[0046] Comparative Example 4 The difference from Example 1 is as follows: In S1, the molar ratio of silicon:aluminum:zirconium metal elements is 2:2:1, and the remaining steps are the same as in Example 1.

[0047] The morphology of carbon nanotubes prepared using the catalyst provided in this comparative example is shown in the figure below. Figure 8 As shown, by Figure 8 It can be seen that the carbon nanotubes prepared in this comparative example are no longer part of the single-walled carbon nanotube series.

[0048] The carbon nanotubes prepared in Examples 1-4 and Comparative Examples 1-4 were subjected to performance tests. The standards followed were: GB / T 26826-2011 - Measurement method of carbon nanotube diameter; GB / T 33243-2016 - Nanotechnology - Characterization of multi-walled carbon nanotubes; GB / T 32871-2016 - Raman spectroscopy for characterization of single-walled carbon nanotubes; GB / T 37152-2018 - Nanotechnology - Carbon nanotube materials - Thin film resistivity.

[0049] The performance test results of the carbon nanotubes prepared in Examples 1-4 and Comparative Examples 1-4 are shown in the table below: Table 1. Performance test results of carbon nanotubes provided in Examples 1-4 and Comparative Examples 1-4 As shown in Table 1, the single-walled carbon nanotubes prepared using the method provided in Example 1 have uniform diameter and lower resistivity, exhibiting superior overall performance. Under identical preparation conditions, the single-walled carbon nanotubes provided in Example 1 demonstrate superior overall performance, indicating that the catalyst provided in Example 1 possesses superior overall catalytic performance.

[0050] By comparing Examples 1 and 2, it can be seen that changing the order of mixing and adding the carrier solution and the active component solution has an obvious impact on the results. Although the target product is still single-walled carbon nanotubes, the quality of the product has changed. The reason for this is that the change in the mixing and adding order affects the loading of the active component in the catalyst body. The uniform distribution of the active component is a key factor in the growth of single-walled carbon nanotubes.

[0051] Comparing Examples 1 and 3, it can be seen that the catalyst prepared using Al2O3-ZrO2 composite as a support can produce some single-walled carbon nanotubes, but at the same time, some oligo-walled carbon nanotubes are also generated. This indicates that SiO2 has a certain regulatory effect in the coupling support. In addition, SiO2 and ZrO2 can form mesoporous materials, which increases the specific surface area of ​​the support, thereby making the distribution of active components more uniform and more conducive to the growth of single-walled carbon nanotubes.

[0052] By comparing Examples 1 and 4, it can be seen that the carbon nanotubes obtained by the catalyst prepared from the SiO2-ZrO2 coupling support are non-single-walled carbon nanotubes, while the aluminum-containing coupling support (Examples 1, 2, and 3) can produce single-walled carbon nanotubes. This is because the support Al2O3 and ZrO2 can form a composite oxide, and a small amount of aluminum ions can enter the ZrO2 lattice, causing certain changes in the lattice, which plays a key role in the performance of the support. Catalysts lacking Al2O3 can only produce non-single-walled carbon nanotubes.

[0053] Comparing Example 1 and Comparative Example 1, it can be seen that although the catalyst prepared using a single ZrO2 support can yield some single-walled carbon nanotubes, the product composition is relatively disordered, with a high proportion of impurities. Examples 1-4 demonstrate that the support for the supported catalyst plays a crucial role in the production of single-walled carbon nanotubes. ZrO2 possesses excellent thermal stability and chemical inertness, and its surface contains both acidic and basic sites. Adjusting the surface acidity and basicity of the ZrO2 support by combining Al2O3 and SiO2 is a key method for optimizing catalytic performance. Al2O3 can enhance the surface acidity of ZrO2, and Al... 3+ The electron-deficient nature of Al₂O₃ facilitates the formation of strong Lewis acid centers, promoting electron transfer reactions such as alkane cracking. Al₂O₃ covers the basic oxygen atoms on the ZrO₂ surface, reducing the basic site density. A small amount of Al₂O₃... 3+Entering the ZrO2 lattice causes lattice distortion and increases the number of acid sites on the surface defects; SiO2 can regulate the acid-base balance of the ZrO2 support, and the weak acidity of SiO2 can dilute the strong acid sites of Al2O3 or ZrO2, avoiding excessive carbon deposition; by precisely controlling the addition method and ratio of Al2O3 and SiO2, the acid-base balance of the ZrO2 support can be "customized" as needed, resulting in single-walled carbon nanotubes with higher purity and better performance.

[0054] By comparing Example 1 and Comparative Examples 2-4, it can be seen that as the molar ratio of aluminum and silicon to zirconium increases, the dominant component of the SiO2-Al2O3-ZrO2 composite support changes, and the resulting carbon nanotubes also undergo fundamental changes; this change indicates that the support has a significant impact on the distribution of the active components of the catalyst.

[0055] Please note that the technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments have been described. However, as long as the combination of these technical features does not contradict each other, it should be considered within the scope of this specification. The above embodiments only illustrate several implementation methods of this application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for preparing a supported catalyst for synthesizing single-walled carbon nanotubes, characterized in that, The preparation method includes the following steps: S1: Pretreatment of the carrier precursor yields carrier solution A; S2: Dissolve the active metal component in water to obtain solution B; S3: Solution A and solution B are mixed under heating and stirring conditions to obtain solution C; S4: Add the metal complexing agent to solution C, heat and stir continuously to obtain a homogeneous solution, continue heating to evaporate the water, and obtain a gel; S5: The gel obtained in S4 is dried to obtain a porous material, which is then ground into powder and calcined in an inert atmosphere to obtain a catalyst precursor. S6: The catalyst precursor obtained in S5 is first cooled to room temperature, then calcined in air atmosphere, and then cooled to obtain the supported catalyst for the synthesis of single-walled carbon nanotubes. In step S1, the carrier precursor is a metal salt or a coupling product of a metal salt; The metal salts include silicon salts, aluminum salts, zirconium salts, and magnesium salts; The active metal component is selected from any one or more of iron, cobalt, tungsten, molybdenum, and nickel.

2. The preparation method according to claim 1, characterized in that, The silicon salt includes sodium silicate; the aluminum salt includes aluminum hydroxide, aluminum nitrate, and aluminum isopropoxide; the zirconium salt includes zirconium oxychloride and zirconium nitrate; and the magnesium salt includes magnesium nitrate.

3. The preparation method according to claim 1, characterized in that, When the carrier precursor is composed of silicon salt, aluminum salt and zirconium salt, the molar ratio of the metal elements silicon, aluminum and zirconium is 0-0.2:0-0.2:

1.

4. The preparation method according to claim 1, 2, or 3, characterized in that, In step S1, the pretreatment includes: preparing a silicate colloidal solution A-1 from silicate salts; dissolving aluminum salts and / or zirconium salts in water to obtain solution A-2; preparing an Al2O3-ZrO2 composite solution from solution A-2 using a homogeneous precipitation method; adding the Al2O3-ZrO2 composite solution to the silicate colloidal solution A-1 under heat preservation and stirring conditions and mixing thoroughly to obtain the carrier solution A.

5. The preparation method according to claim 1, characterized in that, The active components include molybdenum and iron; The molar ratio of molybdenum to iron is 0.01-0.5:

1.

6. The preparation method according to claim 1, characterized in that, In step S3, the mixing is carried out in a rotary evaporator, the rotary evaporator rotating at a speed of 50–500 rpm / min; the mixing temperature is 50–90°C. Before mixing, the pH of solution A is adjusted to 7-10.

7. The preparation method according to claim 1 or 6, characterized in that, The mixing includes: adding solution A to solution B under heating and stirring conditions to obtain solution C; Alternatively, solution B can be added to solution A under heating and stirring conditions to obtain solution C.

8. The preparation method according to claim 1, characterized in that, The preparation method also satisfies one or more of the following conditions: a. In step S4, the metal complexing agent includes one or more of citric acid, tartaric acid, oxalic acid, acetic acid, and formic acid; b. In step S5, the drying process is carried out at a temperature of 100-160°C for 6-10 hours. c. In step S5, the particle size of the powder is 5-40 μm; d. In step S5, the temperature of the first calcination is 400-1000℃, and the time is 1-5h; e. In step S6, the temperature of the second calcination is 400-800℃ and the time is 1-10h.

9. A supported catalyst for the synthesis of single-walled carbon nanotubes, characterized in that, Prepared by the preparation method according to any one of claims 1-8; The supported catalyst is composed of a support and an active component, wherein the total mass of the active component is 2-10% of the mass of the support.

10. The application of a supported catalyst for the synthesis of single-walled carbon nanotubes prepared by the preparation method according to any one of claims 1-8, characterized in that, The steps for preparing single-walled carbon nanotubes using the supported catalyst via chemical vapor deposition include: After the carrier gas is introduced into the fluidized bed reactor, the fluidized bed reactor is heated to 600-800°C, the supported catalyst is added, and the reducing gas is added evenly. After reacting for 10-60 minutes, the raw material gas is added, and the reaction is completed, resulting in a black fluffy solid. Then, after purification, acid washing, and water washing, single-walled carbon nanotubes are obtained. The carrier gas includes any one of nitrogen, helium, and argon; The reducing gas is hydrogen; The raw material gas includes one or more of methane, ethane, ethylene, propane, butane, and propylene.

Images