CN102674316B - Method for preparing composition of carbon nano tube and graphene by using sheet material - Google Patents

Abstract

A method for preparing a carbon nanotube and graphene composite based on a sheet material, the composite is composed of a carbon nanotube and a graphene material, and the carbon nanotube is directly grown on the surface of the graphene. Its preparation method uses the sheet material loaded with catalyst active components as the catalyst, deposits carbon nanotubes and graphene on the sheet material through the process of chemical vapor deposition, and obtains a composite of carbon nanotubes and graphene after purification. things. The invention enriches the types of nano-carbon materials, and the method is easy to enlarge in engineering, realizes batch production, and further promotes the application research of carbon nanotubes and graphene composites.

Description

A method for preparing carbon nanotubes and graphene composites based on sheet materials

technical field

The invention relates to a method for preparing a carbon nanotube and graphene composite, in particular to a method for preparing a carbon nanotube and graphene composite based on a sheet material. It belongs to the technical field of new materials and their preparation.

Background technique

Carbon nanotubes and graphene are the most common and most widely studied carbon nanomaterials. Among them, carbon nanotubes can be regarded as a one-dimensional tubular structure formed by curling one or more layers of graphene sheets. The carbon atoms in the ideal carbon nanotube and graphene structures are all sp ² hybrid bonding, and their structural characteristics determine their excellent performance in electromagnetics, mechanics, and thermals, so that they are used in electronic devices, composite materials, etc. , heat-conducting materials, drug delivery, sensors and other fields have broad application prospects. In addition, the huge specific surface area and structural stability of carbon nanotubes and graphene make them widely used in the field of electrochemistry. However, studies have shown that in practical applications, whether it is carbon nanotubes or graphene, they are easy to aggregate due to the strong van der Waals force between them, which seriously hinders the expression of their properties.

One-dimensional carbon nanotubes and two-dimensional sheet materials are self-assembled into a three-dimensional assembly structure, in which carbon nanotubes are anchored on the surface of the sheet material, making the construction of this three-dimensional structure a carbon An efficient method for nanotube dispersion. For example, Zhang et al. used Fe-loaded clay as a catalyst to grow carbon nanotubes directly on the surface of the clay, thereby promoting the dispersion of carbon nanotubes and improving their performance in composite materials (Zhang WD, et al.Adv.Mater .2006, 18, 73-77.). Wei Fei from Tsinghua University used layered double-hydroxy compound metal hydroxides (LDHs) as catalyst precursors to prepare a three-dimensional network structure assembled by single-walled carbon nanotubes and inorganic metal oxide sheets. Double-walled carbon nanotubes are grown directly from the surface of layered double-hydroxy compound metal oxides (LDOs), the calcined product of LDHs, and fixed on the LDO sheet, thereby achieving good dispersion of single- and double-walled carbon nanotubes (Zhao MQ , et al. Adv. Funct. Mater. 2010, 20, 677–685.). However, in the above work, while the dispersion of carbon nanotubes is improved, a certain amount of inorganic metal oxides are often introduced, which will greatly limit the expression of their electrochemical properties.

The construction of carbon nanotubes and graphene hybrid structures that grow carbon nanotubes directly on the surface of graphene not only promotes the dispersion of carbon nanotubes while avoiding the introduction of inorganic metal oxides, but also promotes the dispersion of graphene . In addition, the three-dimensional hybrid structure of carbon nanotubes and graphene can also construct an effective three-dimensional conductive network, which greatly promotes the performance expression of this material in the field of electrochemistry. Cheng Huiming and others successfully prepared carbon nanotube arrays and graphene composite structures, and studied their electrochemical performance as lithium-ion battery anode materials (Li SS, et al. Adv. Energy Mater. 2011, 1, 486–490 .). However, in this material, the growth of carbon nanotubes is based on electroplating a layer of 5nm thick Al ₂ O ₃ and 1nm thick Fe on the surface of graphene, which hinders the relationship between carbon nanotubes and graphene to a certain extent. contacts and their electron transport. Fan Zhuangjun prepared carbon nanotubes and graphene composites by loading Co and other metal active components on graphene, and using CO as a carbon source to directly grow carbon nanotubes on the surface of graphene (Fan ZJ, et al. Adv. Mater. 2010, 22, 3723-3728.). However, due to the strong interaction between metal nanoparticles and graphene at high temperature, the quality of carbon nanotubes grown by this method is often poor, which affects their performance expression.

With the development of graphene preparation technology, studies have shown that graphene can be deposited on the surface of some metal or non-metal oxides, and these metal or non-metal oxides are often used as carriers for growing carbon nanotubes. Therefore, in view of this consideration, the present invention has developed a method for preparing carbon nanotubes and graphene based on sheet materials loaded with metal active components. After the product is purified, carbon nanotubes can be directly grown on the surface of graphene. carbon nanotube and graphene composites. This method is easy to scale up and achieve mass production, which can greatly promote the application research of carbon nanotubes and graphene composites.

Contents of the invention

The purpose of the present invention is to provide a method for preparing carbon nanotubes and graphene composites based on sheet materials, which enriches the structural types of carbon nanomaterials, and the method is easy to scale up, realizes mass production, and promotes carbon nanotubes and graphite. Applied research on ene complexes.

Technical scheme of the present invention is as follows:

The invention provides a method for preparing carbon nanotubes and graphene composites based on sheet materials, characterized in that the method is carried out as follows:

1) A sheet material loaded with a catalyst active component is used as a catalyst, and the active component of the catalyst is Fe, Co, Ni, Cu, Mo or W, and its content accounts for 0.1% to 50% of the mass of the catalyst;

2) Put the catalyst in a reactor, deposit carbon nanotubes and graphene on the surface of the catalyst through chemical vapor deposition, and then place the obtained product in a product purification device for purification to obtain carbon nanotubes and graphite Carbon nanotubes grow directly on the surface of graphene in carbon nanotubes and graphene composites.

The sheet material is layered double hydroxyl compound metal hydroxide, magnesium oxide, aluminum oxide, silicon dioxide, kaolin, montmorillonite, vermiculite, mica or pseudo-boehmite; the chemical In the vapor phase deposition process, the deposition of carbon nanotubes and graphene is carried out simultaneously or successively, wherein the reaction temperature for depositing carbon nanotubes is 500-1000°C, and the reaction temperature for depositing graphene is 600-1200°C; the chemical The vapor deposition process uses one or a mixture of low-carbon gases below seven carbons, methanol, ethanol, benzene, cyclohexane, n-hexane, toluene, and xylene as carbon sources; uses argon, nitrogen, helium Gas, hydrogen or their mixture is used as the carrier gas, and the partial pressure of the carbon source is controlled to be less than 80% of the total pressure; the reactor is in the form of a fixed bed, a moving bed, a fluidized bed or a combination thereof.

Compared with the prior art, the present invention has the following advantages and beneficial effects: the present invention can obtain carbon nanotube and graphene composite in large quantities; in this composite, carbon nanotube directly grows on the surface of graphene, is a kind of Carbon nanomaterials with new cluster structures. The various catalysts and carbon sources used in the method are cheap and easy to obtain, which is convenient for engineering scale-up and mass production, and lays the foundation for the engineering application of carbon nanotubes and graphene composites.

Description of drawings

Figure 1. Low magnification scanning electron micrographs of carbon nanotubes and graphene composites grown using FeMgAl LDH as a catalyst.

Figure 2 is a high-magnification scanning electron micrograph of carbon nanotubes and graphene composites grown using FeMgAl LDH as a catalyst.

Figure 3 is a transmission electron micrograph of carbon nanotubes and graphene composites grown with FeMgAl LDH as a catalyst.

Figure 4 uses FeMgAl LDH as a catalyst to grow carbon nanotubes and graphene composites with high-resolution transmission electron microscopy.

Figure 5 is a low-magnification scanning electron micrograph of carbon nanotubes and graphene composites grown using FeMoMgAl LDH as a catalyst.

Figure 6 is a low-magnification scanning electron micrograph of carbon nanotubes and graphene composites grown on magnesium oxide loaded with Co components as a catalyst.

Figure 7 is a transmission electron micrograph of carbon nanotubes and graphene composites grown on magnesium oxide loaded with Co components as a catalyst.

Fig. 8 Low magnification scanning electron micrographs of carbon nanotubes and graphene composites grown on layered vermiculite loaded with Fe component as a catalyst.

Detailed ways

The invention provides a method for preparing carbon nanotubes and graphene composites based on sheet materials, characterized in that the method is carried out as follows:

1) A sheet material loaded with a catalyst active component is used as a catalyst, and the active component of the catalyst is Fe, Co, Ni, Cu, Mo or W, and its content accounts for 0.1% to 50% of the mass of the catalyst;

2) Put the catalyst in a reactor, deposit carbon nanotubes and graphene on the surface of the catalyst through chemical vapor deposition, and then place the obtained product in a product purification device for purification to obtain carbon nanotubes and graphite Carbon nanotubes grow directly on the surface of graphene in carbon nanotubes and graphene composites.

The sheet material is layered double hydroxyl compound metal hydroxide, magnesium oxide, aluminum oxide, silicon dioxide, kaolin, montmorillonite, vermiculite, mica or pseudo-boehmite; the chemical In the vapor phase deposition process, the deposition of carbon nanotubes and graphene is carried out simultaneously or successively, wherein the reaction temperature for depositing carbon nanotubes is 500-1000°C, and the reaction temperature for depositing graphene is 600-1200°C; the chemical The vapor deposition process uses one or a mixture of low-carbon gases below seven carbons, methanol, ethanol, benzene, cyclohexane, n-hexane, toluene, and xylene as carbon sources; uses argon, nitrogen, helium Gas, hydrogen or their mixture is used as the carrier gas, and the partial pressure of the carbon source is controlled to be less than 80% of the total pressure; the reactor is in the form of a fixed bed, a moving bed, a fluidized bed or a combination thereof.

The present invention will be further described below through several specific examples.

Example 1: Using FeMgAl LDH as a catalyst to prepare carbon nanotubes and graphene composites through a fixed bed.

FeMgAl LDHs with a Fe content of 10% was used as a catalyst, and 50 mg was uniformly spread in a porcelain boat, and then placed in a tubular fixed-bed reactor. Argon was used as the carrier gas with a flow rate of 600 sccm. Under this atmosphere, the temperature of the reactor was raised from room temperature to 950°C; after that, the reaction temperature was maintained at 950°C, and a mixture of carbon source methane, hydrogen and argon was introduced, wherein the partial pressure of carbon source methane was 80%, A chemical vapor deposition process is performed to simultaneously deposit carbon nanotubes and graphene. After 20 min, the carbon source methane and H ₂ were turned off, and the solid phase product was taken out after cooling to room temperature under an argon atmosphere. The solid phase product is first treated with 3mol/L NaOH aqueous solution at 180°C for 6hr to remove the alumina in the product in the product purification device, and then treated with 1mol/L HCl aqueous solution at 80°C for 6hr to remove the aluminum oxide in the product Magnesium oxide can be used to obtain a carbon nanotube and graphene composite. Its macroscopic appearance is shown in Figure 1. It can be seen that the resulting product is a carbon nanotube and graphene composite. As can be seen from the further high-magnification scanning electron microscope photos in Fig. 2, the carbon nanotubes in the carbon nanotube and graphene composite grow directly on the graphene surface. The transmission electron micrographs shown in FIG. 3 further illustrate the effective connection between carbon nanotubes and graphene in the obtained carbon nanotube and graphene composite. The high-resolution transmission electron microscope photo of Fig. 4 shows that in the obtained carbon nanotube and graphene composite, the obtained carbon nanotube is a single-walled carbon nanotube, and the number of layers of the obtained graphene is 1 to 3 layers, as can be seen Clear graphite layer structure.

Example 2: Using FeMgAl LDH as a catalyst to prepare carbon nanotubes and graphene composites through a fixed bed.

FeMgAl LDHs with a Fe content of 50% was used as a catalyst, and 50 mg was evenly spread in a porcelain boat, and then placed in a tubular fixed-bed reactor. Argon was used as the carrier gas with a flow rate of 600 sccm. Under this atmosphere, the temperature of the reactor was raised from room temperature to 1200 ° C; after that, the reaction temperature was maintained at 1200 ° C, and a mixture of carbon source methane and argon was introduced, wherein the partial pressure of carbon source methane was 80%, and the chemical reaction was carried out. Graphene is deposited by a vapor deposition process. After 10 minutes, the carbon source methane was turned off, and the reactor was cooled to 750°C under an argon atmosphere, and then a mixture of carbon source ethylene, hydrogen and argon was introduced, wherein the partial pressure of carbon source ethylene was 10%, and the chemical vapor phase was carried out. The deposition process deposits carbon nanotubes. After 30 min, the carbon sources ethylene and H ₂ were turned off, and the solid phase product was taken out after cooling the reactor to room temperature under an argon atmosphere. The solid phase product is first treated with 3mol/L NaOH aqueous solution at 180°C for 6hr to remove the alumina in the product in the product purification device, and then treated with 1mol/L HCl aqueous solution at 80°C for 6hr to remove the aluminum oxide in the product Magnesium oxide can be used to obtain carbon nanotube and graphene composites in which carbon nanotube arrays are grown on the surface of graphene.

Example 3: Using FeMoMgAl LDH as a catalyst to prepare carbon nanotubes and graphene composites through a fixed bed.

FeMoMgAl LDHs with a Fe content of 20% and a Mo content of 0.2% were used as catalysts, and 50 mg of FeMoMgAl LDHs was evenly spread in a porcelain boat, and then placed in a tubular fixed-bed reactor. Nitrogen was used as the carrier gas with a flow rate of 600 sccm. In this atmosphere, the temperature of the reactor was raised from room temperature to 750°C, and then a mixture of carbon source propylene, hydrogen and nitrogen was introduced, wherein the partial pressure of carbon source propylene was 10%, and the chemical vapor deposition process was carried out to deposit carbon nanometers. Tube. After 30 minutes, turn off the carbon source propylene and H ₂ , then raise the temperature of the reactor to 1000°C, and then feed the mixed gas of carbon source methane and argon, wherein the partial pressure of carbon source methane is 50%, and carry out chemical vapor deposition process deposition Graphene. After 20 min, the carbon source methane was turned off, and the solid phase product was taken out after the reactor was cooled to room temperature under an argon atmosphere. The solid phase product is first treated with 3mol/L NaOH aqueous solution at 180°C for 6hr to remove the alumina in the product in the product purification device, and then treated with 1mol/L HCl aqueous solution at 80°C for 6hr to remove the aluminum oxide in the product. Magnesium oxide can be used to obtain carbon nanotube and graphene composites in which carbon nanotube arrays are grown on the surface of graphene, the macroscopic appearance of which is shown in Figure 5.

Example 4: Co, Mo and MgO were used as catalysts to prepare carbon nanotubes and graphene composites through a fixed bed.

Co/Mo/MgO flakes with a Co content of 1% and a Mo content of 0.1% were used as a catalyst, and 50 mg was evenly spread in a porcelain boat, and then placed in a tubular fixed-bed reactor. Helium was used as the carrier gas with a flow rate of 600 sccm. Under this atmosphere, the temperature of the reactor was raised from room temperature to 1000 ° C; after that, the reaction temperature was maintained at 1000 ° C, and a mixture of carbon source CO and helium was introduced, wherein the partial pressure of carbon source CO was 50%, and the chemical reaction was carried out. The vapor deposition process simultaneously deposits carbon nanotubes and graphene. After 20 min, the carbon source CO was turned off, and the solid phase product was taken out after cooling to room temperature under a helium atmosphere. Treat the solid-phase product with 1mol/L HCl aqueous solution at 80°C for 6 hours in the product purification device to remove the magnesium oxide in the product, and then the carbon nanotube and graphene composite can be obtained. See Figure 6 for its macroscopic appearance, which can be The resulting product is seen as a carbon nanotube and graphene composite. It can be seen from the further transmission electron microscope photo in Fig. 7 that the carbon nanotubes in the carbon nanotube and graphene composite grow directly on the graphene surface.

Example 5: Using Ni/vermiculite as a catalyst to prepare a carbon nanotube and graphene composite through a fluidized bed.

Ni/vermiculite with a Ni content of 0.1% was used as a catalyst, and 1 g was put into a fluidized bed reactor with a diameter of 20 mm. Argon was used as the carrier gas with a flow rate of 600 sccm. Under this atmosphere, the temperature of the reactor was raised from room temperature to 650°C, and then the reaction temperature was maintained at 650°C, and a mixture of carbon source ethylene, hydrogen and argon was introduced, wherein the partial pressure of carbon source ethylene was 20%, A chemical vapor deposition process was performed to deposit carbon nanotubes. After 30 minutes, the carbon source ethylene was turned off, and the temperature of the reactor was raised to 1000°C under an argon atmosphere, and then a mixed gas of carbon source methane and argon was introduced, wherein the partial pressure of carbon source methane was 60%, and the chemical vapor deposition process was carried out Deposit graphene. After 15 min, the carbon source methane was turned off, and the solid phase product was taken out after the reactor was cooled to room temperature under an argon atmosphere. Treat the solid phase product with 0.5mol/L HF aqueous solution at 80°C for 6hr in the product purification device, and then treat it with 1mol/L HCl aqueous solution at 80°C for 6hr to obtain carbon nanotube and graphene composite , its macroscopic morphology is shown in Figure 8, and it can be seen that the obtained product is a carbon nanotube and graphene composite in which carbon nanotube arrays and graphene sheets overlap.

Example 6: Using Cu/vermiculite as a catalyst to prepare a carbon nanotube and graphene composite through a moving bed.

Cu/vermiculite with a Cu content of 10% was used as a catalyst, and 1 g was put into a moving bed reactor with a diameter of 100 mm. Argon was used as the carrier gas with a flow rate of 600 sccm. Under this atmosphere, the temperature of the reactor was raised from room temperature to 1000 ° C, and then the reaction temperature was maintained at 1000 ° C, and a mixture of carbon source methane and argon was introduced, wherein the partial pressure of carbon source methane was 20%, and the chemical reaction was carried out. Graphene is deposited by a vapor deposition process. After 15 minutes, the carbon source methane was turned off, and the temperature of the reactor was lowered to 500°C under an argon atmosphere, and then a mixture of carbon source acetylene, hydrogen and argon was introduced, wherein the partial pressure of carbon source acetylene was 10%, and chemical vapor phase The deposition process deposits carbon nanotubes. After 30 min, the carbon source acetylene was turned off, and the solid phase product was taken out after the reactor was cooled to room temperature under an argon atmosphere. The solid-phase product is treated with 0.5mol/L aqueous HF solution at 80°C for 6hrs in the product purification device, and then treated with 1mol/L HCl aqueous solution at 80°C for 6hrs to obtain carbon nanotube arrays and graphene Carbon nanotube and graphene composites with overlapping sheets.

Example 7: Using Fe/W/Al ₂ O ₃ as a catalyst to prepare a carbon nanotube and graphene composite through a fixed bed.

Fe/W/Al ₂ O ₃ with a Fe content of 5% and a W content of 0.5% was used as a catalyst, and 50 mg was evenly spread in a porcelain boat, and then placed in a tubular fixed-bed reactor. Argon was used as the carrier gas with a flow rate of 1000 sccm. Under this atmosphere, the temperature of the reactor is raised from room temperature to 1000°C, and then the reaction temperature is maintained at 1000°C, and a mixture of carbon source methanol, hydrogen and argon is introduced, wherein the partial pressure of carbon source methanol is 10%. A chemical vapor deposition process is performed to simultaneously deposit carbon nanotubes and graphene. After 30 min, the carbon source methanol and H ₂ were turned off, and the solid phase product was taken out after cooling the reactor to room temperature under an argon atmosphere. The solid-phase product is treated with 3 mol/L NaOH aqueous solution at 180° C. for 6 hours in a product purification device to obtain a carbon nanotube and graphene composite.

Example 8: Using Fe/Mo/SiO ₂ as a catalyst to prepare a carbon nanotube and graphene composite through a fixed bed.

Fe/Mo/SiO ₂ with a Fe content of 5% and a Mo content of 0.5% was used as a catalyst, and 100 mg was evenly spread in a porcelain boat, and then placed in a tubular fixed-bed reactor. Argon was used as the carrier gas with a flow rate of 1000 sccm. Under this atmosphere, the temperature of the reactor is raised from room temperature to 900°C, and then the reaction temperature is maintained at 900°C, and a mixture of carbon source ethanol, hydrogen and argon is introduced, wherein the partial pressure of carbon source ethanol is 10%, A chemical vapor deposition process is performed to simultaneously deposit carbon nanotubes and graphene. After 30 min, the carbon source ethanol and H ₂ were turned off, and the solid phase product was taken out after cooling the reactor to room temperature under an argon atmosphere. The solid-phase product is treated with 0.5 mol/L HF aqueous solution at 80° C. for 6 hours in a product purification device to obtain a carbon nanotube and graphene composite.

Example 9: Using Fe/Mo/kaolin as a catalyst to prepare a carbon nanotube and graphene composite through a fixed bed.

Fe/Mo/kaolin with a Fe content of 10% and a Mo content of 1% was used as a catalyst, and 100 mg was evenly spread in a porcelain boat, and then placed in a tubular fixed-bed reactor. Argon was used as the carrier gas with a flow rate of 1000 sccm. Under this atmosphere, the temperature of the reactor is raised from room temperature to 800°C, and then the reaction temperature is maintained at 800°C, and a mixture of carbon source benzene, hydrogen and argon is introduced, wherein the partial pressure of carbon source benzene is 5%, A chemical vapor deposition process is performed to simultaneously deposit carbon nanotubes and graphene. After 30 min, the carbon sources of benzene and H ₂ were turned off, the reactor was cooled to room temperature under an argon atmosphere, and the solid phase product was taken out. Treat the solid phase product with 0.5mol/L HF aqueous solution at 80°C for 6hrs in the product purification device, and then treat it with 1mol/L HCl aqueous solution at 80°C for 6hrs to obtain carbon nanotube and graphene composite thing.

Example 10: Using Fe/Mo/montmorillonite as a catalyst to prepare a carbon nanotube and graphene composite through a fixed bed.

Fe/Mo/montmorillonite with a Fe content of 7% and a Mo content of 0.7% was used as a catalyst, and 50 mg was evenly spread in a porcelain boat, and then placed in a tubular fixed-bed reactor. Argon was used as the carrier gas with a flow rate of 1000 sccm. Under this atmosphere, the temperature of the reactor was raised from room temperature to 850°C, and then the reaction temperature was maintained at 850°C, and a mixture of carbon source cyclohexane, hydrogen and argon was introduced, wherein the partial pressure of carbon source cyclohexane For 10%, a chemical vapor deposition process was performed to simultaneously deposit carbon nanotubes and graphene. After 30 min, the carbon source cyclohexane and H ₂ were turned off, the reactor was cooled to room temperature under an argon atmosphere, and the solid phase product was taken out. Treat the solid phase product with 0.5mol/L HF aqueous solution at 80°C for 6hrs in the product purification device, and then treat it with 1mol/L HCl aqueous solution at 80°C for 6hrs to obtain carbon nanotube and graphene composite things.

Example 11: Using Fe/Mo/mica as a catalyst to prepare a carbon nanotube and graphene composite through a fixed bed.

Fe/Mo/mica with a Fe content of 1% and a Mo content of 0.1% was used as a catalyst, and 100 mg was evenly spread in a porcelain boat, and then placed in a tubular fixed-bed reactor. Argon was used as the carrier gas with a flow rate of 1000 sccm. Under this atmosphere, the temperature of the reactor was raised from room temperature to 850°C, and then the reaction temperature was maintained at 850°C, and a mixture of carbon source n-hexane, hydrogen and argon was introduced, wherein the partial pressure of carbon source n-hexane was 5 %, a chemical vapor deposition process was performed to simultaneously deposit carbon nanotubes and graphene. After 30 min, the carbon sources of n-hexane and H ₂ were turned off, the reactor was cooled to room temperature under an argon atmosphere, and the solid phase product was taken out. Treat the solid phase product with 0.5mol/L HF aqueous solution at 80°C for 6hrs in the product purification device, and then treat it with 1mol/L HCl aqueous solution at 80°C for 6hrs to obtain carbon nanotube and graphene composite thing.

Example 12: Using Fe/Mo/pseudoboehmite as a catalyst to prepare a carbon nanotube and graphene composite through a fixed bed.

Fe/Mo/pseudo-boehmite with Fe content of 10% and Mo content of 1% was used as a catalyst, and 100 mg was evenly spread in a porcelain boat, and then placed in a tubular fixed-bed reactor. Argon was used as the carrier gas with a flow rate of 1000 sccm. Under this atmosphere, the temperature of the reactor is raised from room temperature to 700°C, and then the reaction temperature is maintained at 700°C, and a mixture of carbon source toluene, hydrogen and argon is introduced, wherein the partial pressure of carbon source toluene is 5%, A chemical vapor deposition process is performed to simultaneously deposit carbon nanotubes and graphene. After 30 min, the carbon sources toluene and H ₂ were turned off, and the solid phase product was taken out after cooling the reactor to room temperature under an argon atmosphere. Treat the solid phase product with 3mol/L NaOH aqueous solution at 180°C for 6hrs in the product purification device, and then treat it with 1mol/L HCl aqueous solution at 80°C for 6hrs to obtain carbon nanotube and graphene composites .

Example 13: Using Fe/Mo/vermiculite as a catalyst to prepare a carbon nanotube and graphene composite through a combined reactor of a fixed bed and a fluidized bed.

Fe/Mo/vermiculite with a Fe content of 1% and a Mo content of 0.1% was used as a catalyst, and 1 g was put into a fluidized bed reactor with a diameter of 20 mm. Argon was used as a carrier gas with a flow rate of 1000 sccm. Under this atmosphere, the temperature of the reactor was raised from room temperature to 650°C, and then the reaction temperature was maintained at 650°C, and a mixture of carbon source ethylene, hydrogen and argon was introduced, wherein the partial pressure of carbon source ethylene was 20%, Carry out chemical vapor deposition to deposit carbon nanotubes; then use atmospheric velocity to blow the resulting solid-phase product into a fixed-bed reactor with a temperature of 950 ° C, and pass in a mixed gas of carbon source methane and argon, wherein the carbon source methane The partial pressure was 50%, and a chemical vapor deposition process was performed to deposit graphene. After 10 min, the carbon source methane was turned off, and the solid phase product was taken out after the reactor was cooled to room temperature under an argon atmosphere. Treat the solid phase product with 0.5mol/L HF aqueous solution at 80°C for 6hrs in the product purification device, and then treat it with 1mol/L HCl aqueous solution at 80°C for 6hrs to obtain carbon nanotube and graphene composite things.

Example 14: Using Fe/Mo/MgO as a catalyst to prepare a carbon nanotube and graphene composite through a fixed bed.

Fe/Mo/MgO flakes with a Fe content of 1% and a Mo content of 0.1% were used as a catalyst, and 50 mg was evenly spread in a porcelain boat, and then placed in a tubular fixed-bed reactor. Helium was used as the carrier gas with a flow rate of 600 sccm. Under this atmosphere, the temperature of the reactor was raised from room temperature to 600°C; after that, the reaction temperature was maintained at 600°C, and a mixed gas of carbon source xylene, hydrogen and helium was introduced, wherein the partial pressure of carbon source xylene was 5 %, a chemical vapor deposition process was performed to simultaneously deposit carbon nanotubes and graphene. After 20 min, the carbon source xylene and H ₂ were turned off, and the solid phase product was taken out after cooling to room temperature under a helium atmosphere. The solid-phase product is treated with 1mol/L HCl aqueous solution at 80°C for 6 hours in a product purification device to remove magnesium oxide in the product, and the carbon nanotube and graphene composite can be obtained.

Example 15: Using Co/MgO as a catalyst to prepare a carbon nanotube and graphene composite through a fixed bed.

The flaky Co/MgO with a Co content of 5% was used as a catalyst, and 50 mg was uniformly spread in a porcelain boat, and then placed in a tubular fixed-bed reactor. Argon was used as the carrier gas with a flow rate of 600 sccm. Under this atmosphere, the temperature of the reactor was raised from room temperature to 950°C; after that, the reaction temperature was maintained at 950°C, and a mixture of carbon source methane, ethylene, hydrogen and argon was introduced, wherein the partial pressure of carbon source methane was 5 %, the partial pressure of ethylene was 5%, and the chemical vapor deposition process was carried out to simultaneously deposit carbon nanotubes and graphene. After 20 min, the carbon sources methane, ethylene and H ₂ were turned off, and the solid phase product was taken out after cooling to room temperature under an argon atmosphere. The solid-phase product is treated with 1mol/L HCl aqueous solution at 80°C for 6 hours in a product purification device to remove magnesium oxide in the product, and the carbon nanotube and graphene composite can be obtained.

Claims (3)

1. a method for preparing carbon nanotubes and graphene composites based on sheet material, is characterized in that the method is carried out as follows: 1) A sheet material loaded with a catalyst active component is used as a catalyst, and the active component of the catalyst is Fe, Co, Ni, Cu, Mo or W, and its content accounts for 0.1% to 50% of the mass of the catalyst; the The sheet material is layered double hydroxyl compound metal hydroxide, magnesium oxide, aluminum oxide, silicon dioxide, kaolin, montmorillonite, vermiculite, mica or pseudo-boehmite. 2) The catalyst is placed in a reactor, and carbon nanotubes and graphene are deposited on the surface of the catalyst through a chemical vapor deposition process; the deposition of carbon nanotubes and graphene is carried out simultaneously or sequentially, wherein the deposition of carbon nanotubes The reaction temperature is 500-1000°C, and the reaction temperature for depositing graphene is 600-1200°C; then the obtained product is placed in a product purification device for purification to obtain carbon nanotubes and graphene composites, carbon nanotubes and graphite Carbon nanotubes grow directly on the surface of graphene in the graphene composite. 2. A method for preparing carbon nanotubes and graphene composites based on sheet materials according to claim 1, characterized in that: the chemical vapor deposition process described in step 2) uses low-carbon gases below seven carbons , methanol, ethanol, benzene, cyclohexane, n-hexane, toluene, and xylene, or a mixture of one or more of them as the carbon source; use argon, nitrogen, helium, hydrogen, or their mixture as the carrier gas, Control the partial pressure of the carbon source to be less than 80% of the total pressure. 3. A method for preparing carbon nanotubes and graphene composites based on sheet materials according to claim 1 or 2, characterized in that: the reactor used in the chemical vapor deposition process in step 2) is a fixed bed, moving bed, fluidized bed or their combination.

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