A supported catalyst for synthesizing single-walled carbon nanotubes and a preparation method and application thereof

Abstract

The application provides a supported catalyst for synthesizing single-walled carbon nanotubes, a preparation method and application thereof. The supported catalyst for synthesizing single-walled carbon nanotubes is prepared by the preparation method, which comprises the following steps: pre-treating a carrier precursor to obtain solution A; dissolving a metal active component in water to obtain solution B; mixing solution A and solution B to obtain solution C; adding a metal complexing agent into solution C and heating and stirring to obtain a uniformly mixed solution, and continuously heating and evaporating water to obtain a gel; drying the gel to obtain a porous material, grinding the porous material into powder, and performing first calcination to obtain a catalyst precursor; and performing second calcination after cooling the catalyst precursor. The carrier precursor is a metal salt or a coupling compound of a metal salt; the metal salt comprises a silicon salt, an aluminum salt, a zirconium salt and a magnesium salt; and the metal active component is selected from iron, cobalt, tungsten, molybdenum and nickel. Single-walled carbon nanotubes with better comprehensive performance can be prepared by using the supported catalyst through a chemical vapor deposition method.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of carbon nanotube preparation and catalyst, and particularly relates to a supported catalyst for synthesizing single-walled carbon nanotubes and a preparation method and application thereof. BACKGROUND

[0002] Single-walled carbon nanotubes can be regarded as a geometric structure body curled from a single layer of graphene, and due to the full carbon-carbon covalent bond characteristics in the structure, exhibit excellent thermodynamic, electrical and other properties, and have great application potential in many fields such as new energy vehicles, energy storage batteries, nanoelectronic devices, composite materials, catalyst carriers and the like, and are regarded as an industrial universal additive. With the rapid development of related industries, the demand for single-walled carbon nanotubes has increased significantly.

[0003] At present, the preparation methods of single-walled carbon nanotubes mainly include chemical vapor deposition method, laser evaporation method, plasma arc method and the like. Single-walled carbon nanotubes need to have a suitable catalyst matched therewith, in addition, traditional metal catalysts such as Fe, Ni, Co and related alloys, due to moderate melting point, cannot avoid aggregation and deactivation at high temperature, which limits the quality and yield of single-walled carbon nanotubes at high temperature. Although some high-melting-point metals can be used as catalysts, there are problems such as complex preparation process, high equipment requirement, low reproducibility, difficult removal of metal impurities and easy influence on physical properties of single-walled carbon nanotubes.

[0004] Therefore, it has important practical significance to develop a catalyst which 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.

[0005] In view of this, the present application is proposed. SUMMARY

[0006] The present application aims to provide a supported catalyst for synthesizing single-walled carbon nanotubes and a preparation method and application thereof, to solve the above problems.

[0007] To achieve the above purpose, the present application adopts the following technical solutions:

[0008] The present application first provides a preparation method of a supported catalyst for synthesizing single-walled carbon nanotubes, which comprises the following steps:

[0009] S1: pretreating a carrier precursor to obtain a carrier solution A;

[0010] S2: dissolving a metal active component in water to obtain a solution B;

[0011] S3: mixing the solution A and the solution B under the condition of heating and stirring to obtain a solution C;

[0012] S4: adding a metal complexing agent into solution C, continuously heating and stirring to obtain a mixed solution, continuously heating and evaporating water to obtain a gel;

[0013] S5: drying the gel obtained in S4 to obtain a porous material, then grinding the porous material into a powder, and performing a first calcination under an inert atmosphere to obtain a catalyst precursor;

[0014] S6: cooling the catalyst precursor obtained in S5 to room temperature, then performing a second calcination under an air atmosphere, and then cooling to obtain the supported catalyst for synthesizing single-walled carbon nanotubes;

[0015] In the step S1, the carrier precursor is a metal salt or a coupling product of a metal salt.

[0016] The metal salt includes a silicon salt, an aluminum salt, a zirconium salt, and a magnesium salt; preferably, the silicon salt includes sodium silicate; the aluminum salt includes aluminum hydroxide, aluminum nitrate, and aluminum isopropylate; the zirconium salt includes zirconium oxychloride and zirconium nitrate; and the magnesium salt includes magnesium nitrate.

[0017] Further preferably, when the carrier precursor is composed of a silicon salt, an aluminum salt, and a zirconium salt, the molar ratio of the metal elements silicon, aluminum, and zirconium is 0-0.2:0-0.2:1.

[0018] The metal active component is selected from any one or more of iron, cobalt, tungsten, molybdenum, and nickel; preferably, the active component includes molybdenum and iron; further preferably, the molar ratio of the molybdenum and iron is 0.01-0.5:1.

[0019] Optionally, in the step S1, the pretreatment includes: preparing a silicic acid colloidal solution A-1 from a silicon salt, dissolving an aluminum salt and / or a zirconium salt in water to obtain a solution A-2, preparing an Al2O3-ZrO2 composite solution from the solution A-2 by a homogeneous precipitation method, and adding the Al2O3-ZrO2 composite solution to the silicic acid colloidal solution A-1 under the condition of heat preservation and stirring, and fully mixing to obtain the carrier solution A.

[0020] Preferably, in the step S3, the mixing is performed in a rotary evaporation reaction kettle, the rotation speed of the rotary evaporation reaction kettle is 50-500 rpm / min, and the temperature of the mixing is 50-90°C.

[0021] Preferably, the pH value of the solution A is adjusted to 7-10 before the mixing.

[0022] Further preferably, the pH value of the solution A is adjusted to 8-10 before the mixing.

[0023] Further preferably, the mixing includes: adding the solution A into the solution B under the condition of heating and stirring to obtain the solution C.

[0024] Alternatively, solution B is added to solution A under heating and stirring to obtain solution C.

[0025] Preferably, when the pre-treatment is: preparing a silicate colloid solution A-1 from a silicon salt, dissolving an aluminum salt and / or a zirconium salt in water to obtain solution A-2, preparing an Al2O3-ZrO2 composite solution by homogeneous precipitation method from solution A-2; and adding the Al2O3-ZrO2 composite solution to the silicate colloid solution A-1 under heating and stirring and mixing thoroughly to obtain the carrier solution A, before the 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; the pH value of solution A-1 is adjusted to 2-4 to promote the formation of colloid, and then mixed with A-2 to make the pH value of the mixed solution between 7-10, which can accelerate the gelation process.

[0026] Optionally, the preparation method further satisfies one or more of the following conditions:

[0027] a. In the step S4, the metal complexing agent comprises one or more of citric acid, tartaric acid, oxalic acid, acetic acid, and formic acid;

[0028] b. In the step S5, the drying treatment is performed at a temperature of 100-160℃ for 6-10h;

[0029] c. In the step S5, the particle size of the powder is 5-40μm;

[0030] Preferably, the particle size of the powder is 20-30μm;

[0031] d. In the step S5, the first calcination is performed at a temperature of 400-1000℃ for 1-5h;

[0032] e. In the step S6, the second calcination is performed at a temperature of 400-800℃ for 1-10h;

[0033] Preferably, the second calcination is performed at a temperature of 600-700℃.

[0034] The application also provides a supported catalyst for synthesizing single-walled carbon nanotubes, which is prepared by the above preparation method.

[0035] The supported catalyst comprises a carrier and an active component, wherein the total mass of the active component is 2-10% of the mass of the carrier.

[0036] The third aspect of the present application provides an application of the supported catalyst for synthesizing single-walled carbon nanotubes prepared by the preparation method.

[0037] After the carrier gas is introduced into the fluidized bed reactor, the fluidized bed reactor is heated to 600-800 DEG C, the supported catalyst is added, the reducing gas is uniformly added, after 10-60 minutes of reaction, the raw material gas is added, the reaction is completed, and a black fluffy solid is obtained, and then the single-walled carbon nanotubes are obtained by sequentially purifying, pickling and washing.

[0038] The carrier gas includes any one of nitrogen, helium and argon.

[0039] The reducing gas is hydrogen.

[0040] The raw material gas includes one or more of methane, ethane, ethylene, propane, butane and propylene.

[0041] Different from the preparation method of the conventional catalyst, the present application uses the coupling of one or more of zirconium oxychloride, zirconium nitrate, magnesium nitrate, aluminum hydroxide, aluminum nitrate, aluminum isopropyl alcohol and sodium silicate as the carrier precursor to prepare the supported catalyst, and by preparing the carrier precursors according to the molar ratio during the preparation of the carrier, the prepared carrier precursors are mixed to obtain a composite carrier; in the mixing process of the carrier precursors, the obtained Al2O3-ZrO2 composite solution is slowly added to the silicic acid colloid solution under stirring conditions within 1-2 hours of the silicic acid colloid condensation process, the silicic acid colloid prevents the Al2O3-ZrO2 composite particles from agglomerating by electrostatic repulsion when the pH is greater than 2, and when the pH is adjusted to 8-10, the negative charge density of the silicic acid colloid is enhanced, thereby improving the dispersibility of the Al2O3-ZrO2 composite, and the performance of the composite carrier is more stable.

[0042] The present application has the following advantages:

[0043] The preparation method of the supported catalyst provided by the present application is different from the carrier of the conventional supported catalyst, the composition of the composite carrier is accurately controlled by the molar ratio, the surface acidity and alkalinity of the carrier are adjusted, the performance of the carrier is effectively improved, the dispersion of the active component is improved by rotary evaporation coating, and the structure and catalytic performance of the catalyst are effectively improved, and the prepared catalyst is used for the growth of single-walled carbon nanotubes, which can significantly improve the growth rate of carbon nanotubes.

[0044] The active metal component and the carrier structure of the catalyst provided by the present application can be accurately controlled.

[0045] The single-walled carbon nanotubes prepared by using the supported catalyst provided by the application have a diameter of 1-5 nm, a tube length of 5-50 μm, a powder resistivity of 0.8 Ω·cm at the lowest, and a growth multiplication of 15-20 times. BRIEF DESCRIPTION OF DRAWINGS

[0046] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the drawings needed in the specific embodiments or the prior art description will be briefly introduced as follows. Obviously, the drawings described below are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0047] Figure 1 The appearance morphology of the carbon nanotubes provided for Example 1 is shown in the figure;

[0048] Figure 2 The appearance morphology of the carbon nanotubes provided for Example 2 is shown in the figure;

[0049] Figure 3 The appearance morphology of the carbon nanotubes provided for Example 3 is shown in the figure;

[0050] Figure 4 The appearance morphology of the carbon nanotubes provided for Example 4 is shown in the figure;

[0051] Figure 5 The appearance morphology of the carbon nanotubes provided for Comparative Example 1 is shown in the figure;

[0052] Figure 6 The appearance morphology of the carbon nanotubes provided for Comparative Example 2 is shown in the figure;

[0053] Figure 7 The appearance morphology of the carbon nanotubes provided for Comparative Example 3 is shown in the figure;

[0054] Figure 8 The appearance morphology of the carbon nanotubes provided for Comparative Example 4 is shown in the figure. DETAILED DESCRIPTION

[0055] In order to make the purpose, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be described clearly and completely in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0056] Example 1

[0057] The embodiment first provides a preparation method of a supported catalyst for single-walled carbon nanotube growth, and the specific steps are as follows:

[0058] S1: according to the molar ratio of silicon: aluminum: zirconium metal elements 0.1:0.1:1, take sodium silicate 12.2g, aluminum nitrate 21.3g, and zirconium oxychloride 17.8g, prepare a silicic acid colloid solution A-1 from the sodium silicate, adjust the pH value of the solution A-1 to 2-4, dissolve the aluminum nitrate and the zirconium oxychloride in water to obtain a solution A-2, adjust the pH value of the solution A-2 solution to 9-10, and then use the uniform precipitation method to prepare an Al2O3-ZrO2 composite solution from the solution A-2; slowly add the Al2O3-ZrO2 composite solution to the silicic acid colloid solution A-1 under the condition of 50-80℃ heat preservation and stirring, and fully mix to obtain a SiO2-Al2O3-ZrO2 carrier solution A.

[0059] S2: according to the molar ratio of metal elements molybdenum: iron 0.23:1, take 3.078g of active component, that is, take 9.33g of iron nitrate and 1.89g of ammonium molybdate; dissolve the iron nitrate and the ammonium molybdate in water to obtain a solution B.

[0060] S3: adjust the pH value of the solution A to 8 in a rotary evaporation reaction kettle, slowly add the solution B to the solution A under the condition of heating and stirring to obtain a solution C; the mixing temperature is controlled at 90℃; and the stirring speed is controlled at 500rpm / min.

[0061] S4: slowly add 13.89g of metal complexing agent citric acid to the solution C, keep heating and stirring to obtain a uniformly mixed solution, continue to heat and evaporate water to obtain a gel.

[0062] S5: place the gel obtained in S4 in an oven at 100℃ for 6h to obtain a porous material, then grind the porous material into a 20-30μm powder, and then place the powder in a 600℃ nitrogen atmosphere for calcination for 2h to obtain a catalyst precursor with a stable structure.

[0063] S6: after the catalyst precursor obtained in S5 is cooled to room temperature, place the catalyst precursor in an air atmosphere for high-temperature calcination at 700℃ for 5h, and then cool to room temperature to obtain a supported catalyst.

[0064] S7: use the supported catalyst prepared in S6 to prepare single-walled carbon nanotubes, and the specific steps are as follows:

[0065] After the carrier gas nitrogen is introduced into the fluidized bed reaction furnace, slowly heat the fluidized bed reaction furnace to 800℃, add the catalyst obtained in S6, uniformly add reducing gas hydrogen, after reaction for 15 minutes, add raw material gas methane, complete the reaction, and obtain a black fluffy solid, and then sequentially purify, acid wash, and water wash to obtain single-walled carbon nanotubes; the specific gravity of the prepared single-walled carbon nanotubes is 20 times.

[0066] The appearance and morphology of the single-walled carbon nanotubes prepared in this example are shown in Fig. 2, which shows that the prepared single-walled carbon nanotubes have uniform diameters and a large aspect ratio. Figure 1 Figure 1 The appearance and morphology of the single-walled carbon nanotubes prepared in this example are shown in Fig. 2, which shows that the prepared single-walled carbon nanotubes have uniform diameters and a large aspect ratio.

[0067] Example 2

[0068] The difference between this example and Example 1 is that the mixing in Step S3 of this example is to add Solution A to Solution B to obtain Solution C, i.e. Step S3 in this example is:

[0069] S3: The pH value of Solution A is adjusted to 8, and then Solution A is slowly added to Solution B under heating and stirring to obtain Solution C. The mixing process is carried out in a rotary evaporation reactor. The mixing temperature is controlled at 90°C, and the stirring speed is controlled at 500 rpm / min.

[0070] The remaining steps are the same as in Example 1.

[0071] The appearance and morphology of the single-walled carbon nanotubes prepared using the catalyst prepared in this example are shown in Fig. 2, which shows that the prepared single-walled carbon nanotubes have uniform diameters and a large aspect ratio. Figure 2 Figure 2 The appearance and morphology of the single-walled carbon nanotubes prepared using the catalyst prepared in this example are shown in Fig. 2, which shows that the prepared single-walled carbon nanotubes have uniform diameters and a large aspect ratio.

[0072] Example 3

[0073] The difference between this example and Example 1 is that the carrier precursor used to prepare the carrier solution A in this example does not include a silicon salt, i.e. Step S1 in this example is:

[0074] S1: According to the molar ratio of aluminum to zirconium metal elements of 0.1:1, 21.3 g of aluminum nitrate and 17.8 g of zirconium oxychloride are taken. The aluminum nitrate and zirconium oxychloride are dissolved in water to obtain an Al2O3-ZrO2 complex, i.e. the carrier solution A, by a uniform precipitation method.

[0075] The remaining steps are the same as in Example 1.

[0076] The appearance and morphology of the single-walled carbon nanotubes prepared using the catalyst prepared in this example are shown in Fig. 2, which shows that the prepared single-walled carbon nanotubes have uniform diameters and a large aspect ratio. Figure 3 Figure 3 The appearance and morphology of the single-walled carbon nanotubes prepared using the catalyst prepared in this example are shown in Fig. 2, which shows that the prepared single-walled carbon nanotubes have uniform diameters and a large aspect ratio.

[0077] Example 4

[0078] The difference between this example and Example 1 is that the carrier precursor used to prepare the carrier solution A in this example does not include an aluminum salt, i.e. Step S1 in this example is:

[0079] ​​​S1: according to the molar ratio of silicon: zirconium metal elements 0.1:1, take sodium silicate 12.2g, zirconium oxychloride 17.8g; the sodium silicate is made into a silicic acid colloidal solution A-1; the zirconium oxychloride is dissolved in water and hydrolyzed to obtain solution A-2; the solution A-2 is slowly added to the silicic acid colloidal solution A-1 under the condition of heat preservation and stirring and fully mixed to obtain the SiO2-ZrO2 carrier solution A.

[0080] The remaining steps are the same as those of Example 1.

[0081] The appearance morphology of the carbon nanotubes prepared using the catalyst provided in the example is shown in FIG. 1, and it can be seen from FIG. 1 that the carbon nanotubes prepared in the example are not single-walled carbon nanotubes, and the outer wall of the carbon nanotubes prepared is irregular. Figure 4 Figure 4

[0082] Comparative Example 1

[0083] The difference from Example 1 is that:

[0084] S1: according to the molar ratio of silicon: aluminum: zirconium metal elements 0:0:1, take zirconium oxychloride 17.8g; dissolve it in water to prepare a solution, and then hydrolyze it to obtain nano-sized ZrO2 as the carrier solution A.

[0085] The remaining steps are the same as those of Example 1.

[0086] The appearance morphology of the carbon nanotubes prepared using the catalyst provided in the example is shown in FIG. 1, and it can be seen from FIG. 1 that the carbon nanotubes prepared in the example are not single-walled carbon nanotubes, and the outer wall of the carbon nanotubes prepared is irregular. Figure 5 Figure 5 It can be seen from FIG. 1 that the comparative example can obtain single-walled carbon nanotubes, but the obtained carbon nanotubes are not pure, and are mixed with relatively chaotic carbon nanotubes, and there are more impurities.

[0087] Comparative Example 2

[0088] The difference from Example 1 is that:

[0089] 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 those of Example 1.

[0090] The appearance morphology of the carbon nanotubes prepared using the catalyst provided in the example is shown in FIG. 1, and it can be seen from FIG. 1 that the carbon nanotubes prepared in the example are not single-walled carbon nanotubes, and the outer wall of the carbon nanotubes prepared is irregular. Figure 6 Figure 6 It can be seen from FIG. 1 that the comparative example can obtain single-walled carbon nanotubes, but the obtained carbon nanotubes are not pure, and are mixed with relatively chaotic carbon nanotubes, and there are more impurities.

[0091] Comparative Example 3

[0092] The difference from Example 1 is that:

[0093] In S1, the molar ratio of silicon: aluminum: zirconium metal elements is 1:1:1, and the remaining steps are the same as those of Example 1.​​​​

[0094] The appearance morphology of the carbon nanotubes prepared using the catalyst provided in the present comparative example is shown in FIG. 2, from which it can be seen that the carbon nanotubes prepared in the present comparative example are not single-walled carbon nanotubes. Figure 7 Figure 7

[0095] Comparative Example 4

[0096] The difference between Example 1 and the present comparative example is that:

[0097] In S1, the molar ratio of silicon, aluminum and zirconium metal elements is 2:2:1, and the remaining steps are the same as those of Example 1.

[0098] The appearance morphology of the carbon nanotubes prepared using the catalyst provided in the present comparative example is shown in FIG. 2, from which it can be seen that the carbon nanotubes prepared in the present comparative example are not single-walled carbon nanotubes. Figure 8 Figure 8

[0099] The carbon nanotubes prepared in Examples 1-4 and Comparative Examples 1-4 were tested for performance, and the standards for performing the tests were: GB / T 26826-2011 - Method for measuring the diameter of carbon nanotubes; GB / T 33243-2016 - Nanotechnology - Multi-walled carbon nanotube characterization; GB / T 32871-2016 - Single-walled carbon nanotube characterization - Raman spectroscopy; and GB / T 37152-2018 - Nanotechnology - Carbon nanotube materials - Sheet resistance.

[0100] The performance test results of the carbon nanotubes prepared in Examples 1-4 and Comparative Examples 1-4 are shown in the following table:

[0101] Table 1 Performance test results of the carbon nanotubes provided in Examples 1-4 and Comparative Examples 1-4

[0102]

[0103] As can be seen from Table 1, the single-walled carbon nanotubes prepared using the method provided in Example 1 have uniform tube diameters and smaller resistivities, and exhibit better comprehensive performance. Under the condition that the preparation of carbon nanotubes is completely the same, the single-walled carbon nanotubes provided in Example 1 have better comprehensive performance, which indicates that the catalyst provided in Example 1 has superior comprehensive catalytic performance.

[0104] ​​​​By comparing Example 1 and Example 2, it can be seen that the mixing order of the carrier solution and the active component solution is changed, and the effect on the results is obvious, although the target product of growth is still single-walled carbon nanotubes, but the quality of the product has changed; the reason is that the change of the mixing order affects the loading of the active component of the catalyst body, and the uniform distribution of the active component is a key factor for the growth of single-walled carbon nanotubes.

[0105] By comparing Example 1 and Example 3, it can be seen that the catalyst prepared by using Al2O3-ZrO2 complex as the carrier can obtain part of single-walled carbon nanotubes, but also generates part of multi-walled carbon nanotubes, which shows from another aspect that SiO2 in the coupling carrier has a certain regulating effect; in addition, SiO2 and ZrO2 can form mesoporous materials, so that the specific surface area of the carrier is increased, so that the active component is more uniformly distributed, which is more conducive to the growth of single-walled carbon nanotubes.

[0106] By comparing Example 1 and Example 4, it can be seen that the catalyst prepared by using SiO2-ZrO2 coupling carrier obtains non-single-walled carbon nanotubes, while the coupling carrier containing aluminum (Example 1, Example 2, Example 3) can prepare single-walled carbon nanotubes, because the carrier Al2O3 and ZrO2 can form a complex oxide, and a small amount of aluminum ions can enter the ZrO2 lattice, causing a certain change in the lattice, which plays a key role in the performance of the carrier. The catalyst lacking Al2O3 carrier can only produce non-single-walled carbon nanotubes.

[0107] By comparing Example 1 and Comparative Example 1, it can be seen that the catalyst prepared by using a single ZrO2 carrier can obtain part of single-walled carbon nanotubes, but the product composition is relatively chaotic and contains more carbon; by Examples 1-4, it can be seen that the carrier of the supported catalyst plays an extremely important role in the production of single-walled carbon nanotubes. ZrO2 has excellent thermal stability and chemical inertness, and its surface simultaneously exists acidic sites and basic sites. Adjusting the surface acidity and basicity of the ZrO2 carrier by complexing Al2O3 and SiO2 is a key means to optimize the catalytic performance; Al2O3 can enhance the surface acidity of ZrO2, and the electron-deficient characteristics of Al 3+ promote electron transfer reactions such as alkane cracking, and Al2O3 covers the basic oxygen atoms on the surface of ZrO2, reducing the density of basic sites. A small amount of Al 3+ enters the ZrO2 lattice, causing lattice distortion and increasing the surface defect acid sites; SiO2 can regulate the balance of the acidity and basicity of the ZrO2 carrier, and the weak acidity of SiO2 can dilute the strong acid sites of Al2O3 or ZrO2, avoiding excessive carbon deposition; precise control of the addition method and ratio of Al2O3 and SiO2 can achieve "on-demand customization" of the acidity and basicity of the ZrO2 carrier, and obtain single-walled carbon nanotubes with higher purity and better performance.

[0108] By comparing Example 1 and Comparative Examples 2-4, it can be seen that as the relative molar ratio of aluminum, silicon to zirconium increases, the dominant component of the SiO2-Al2O3-ZrO2 composite carrier changes, and the obtained carbon nanotubes also have a fundamental change; this change shows that the carrier has a relatively significant influence on the distribution of the active component of the catalyst.

[0109] Please note that the technical features of the above examples can be combined in any way, and for the sake of brevity, not all possible combinations of the technical features in the above examples are described, however, as long as the combination of the technical features does not exist contradictory, it should be considered as the scope of the description. The above examples only express several embodiments of the present application, and the description is more specific and detailed, but it should not be construed as limiting the scope of the patent. It should be noted that for those skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are within the scope of the present application. Therefore, the scope of the patent of the present application should be subject to 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: Add solution B to solution A 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 composed of silicon salt, aluminum salt, and zirconium salt, wherein 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 any one or more of iron, cobalt, tungsten, molybdenum, and nickel. 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; Before mixing, the pH of solution A-1 is adjusted to 2-4 and the pH of solution A-2 is adjusted to 9-11. The pH of solution A-1 is adjusted to 2-4 to promote colloid formation, and then it is mixed with A-2 to make the pH of the mixed solution between 7-10.

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

3. 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.

4. 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 to 500 rpm; and the mixing temperature is 50 to 90°C.

5. 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.

6. 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 1-5; 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.

7. 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 1-5, 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.

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