WO2016140443A1 - Catalyst produced by using hydrothermal synthesis coprecipitation technique, and carbon nanotube manufactured by using same - Google Patents

Abstract

The present invention relates to: a method of producing a catalyst by using a hydrothermal synthesis coprecipitation technique, and a catalyst for synthesizing carbon nanotubes obtained through same; and to a method of producing a catalyst by using a hydrothermal synthesis coprecipitation technique, which can produce carbon nanotubes having small diameters without a calcination process and which can reduce production time, and a catalyst for synthesizing carbon nanotubes obtained through same.

Description

Catalyst prepared using hydrothermal synthesis coprecipitation and carbon nanotubes prepared using same

This application claims the benefit of priority based on Korean Patent Application No. 10-2015-0030376 filed on March 4, 2015, and all contents disclosed in the literature of that Korean patent application are incorporated as part of this specification.

The present invention relates to a catalyst using a hydrothermal synthesis coprecipitation method and a carbon nanotube obtained therefrom, which can produce a low diameter carbon nanotube without a sintering step and can shorten the production time and a carbon nanotube obtained therefrom. It is about.

Generally, carbon nanotubes (hereinafter referred to as 'CNT') are cylindrical carbon tubes having a diameter of about 3 to 150 nm, specifically about 3 to 100 nm, and having a length several times the diameter, for example, 100 times or more. Refers to. These CNTs consist of layers of aligned carbon atoms and have different types of cores. Such CNTs are also called, for example, carbon fibrils or hollow carbon fibers.

On the other hand, such CNTs are of industrial importance in the manufacture of composites due to their excellent electrical and conductivity and physical strength, and have high utility in the field of electronic materials, energy materials and many other fields.

However, CNTs do not exist as strands, but as CNTs grow through the reduction of metals based on high van der Waals interactions and catalyst supports due to nanometer-level small diameters, CNTs form aggregates around the support. However, in order to express excellent properties of CNTs, it is necessary to disperse the strands of CNTs, and the biggest obstacle to the current CNT-related applications is the dispersion of CNTs.

The dispersibility of CNTs is related to the structure of aggregates of CNTs. The structure of aggregates is largely divided into entangle type and bundle type.

The entangled form has a high bulk density with CNTs twisted without orientation and having a spherical or potato shape. The entangled type can produce high yield CNTs and can be produced with low cost CNTs due to its simple fluidized bed process, while the CNTs are severely twisted and thus have poor dispersion.

On the other hand, in the case of the bundle type, the CNTs have a directivity to form an aggregate and have a pupa form or a rod form, and have a low bulk density. In the case of the bundle type, low CNT productivity is low due to low bulk density, and inexpensive CNT production is difficult due to unstable process conditions. The remaining length of CNTs is long, so the CNTs have excellent characteristics when used as conductive additives in polymers.

Another important property of CNTs is the diameter and length of the CNTs. In order to have a high effect on the product, the diameter of the CNTs must be small. This is advantageous for the formation of a one-dimensional strand network because the number of CNT strands per mass of CNTs is large, and the contact area with a matrix of a polymer or a metal is larger, which results in a higher CNT effect. As for the length of CNT, the residual length after CNT dispersion in a polymer of CNT polymer or metal is important. The longer the length of CNT, the longer the residual length after CNT dispersion. The longer the residual length after the dispersion of CNTs, the better the electrical properties are realized because of the favorable formation of the CNT one-dimensional strand network, which facilitates the passage of electrons, and the higher the physical strength due to the higher interaction with the matrix. Therefore, CNTs are advantageous in that the CNTs have small diameters and long lengths in the form of uniform bundles.

The problem to be solved by the present invention,

It is to provide a method for producing a small diameter and long length of uniform bundle type CNT.

Another problem to be solved by the present invention,

It is to provide a method for controlling the bundle size and CNT yield of the bundled CNT, the diameter of the CNT.

The present invention to solve the above problems,

Adding a metal salt of the catalyst component, a metal salt of the active component, and a coprecipitation agent to an aqueous solvent to obtain an aqueous coprecipitation-containing metal salt solution;

Heating the co-precipitation-containing metal salt aqueous solution at a temperature of 120 ° C. to 200 ° C. to obtain a co-precipitated slurry; And

Separating and drying the slurry; provides a method for producing a catalyst comprising a.

The present invention to solve the other problem,

It provides a catalyst for producing CNTs obtained by the above production method.

The present invention to solve the above another problem,

Injecting the catalyst for preparing the CNTs into the reactor;

Injecting a carbon source or a mixed gas of hydrogen and nitrogen into the reactor at a temperature of 500 to 900 ° C .; And

It provides a method of producing a CNT comprising a; growing the CNT through decomposition of the carbon source on the surface of the supported catalyst.

In order to solve the above another problem, the present invention provides a CNT obtained by the production method.

The method of preparing the catalyst using the hydrothermal synthesis method according to the present invention does not include a calcination step, and thus is useful for the preparation of low-diameter CNTs. A uniform bundle is formed by controlling CNT reaction conditions and the like, and the CNTs have a small diameter and a long length. It is possible to get In addition, it can be manufactured in a short time to provide the effect of improved economic efficiency.

1 to 3 show SEM images of the coprecipitation catalysts obtained in Comparative Examples 1 to 3, respectively.

4 to 7 show SEM images of the coprecipitation catalyst obtained in Example 1. FIG.

8 to 11 show SEM images of the coprecipitation catalyst obtained in Example 2. FIG.

12 to 14 show SEM images of CNTs obtained in Comparative Examples 4 to 6, respectively.

15 and 16 show SEM images of CNTs obtained in Example 3. FIG.

17 to 19 show SEM images of CNTs obtained in Example 4. FIG.

The terms or words used in this specification and claims are not to be construed as limiting in their usual or dictionary meanings, and the inventors may appropriately define the concept of terms in order to best describe their invention. Based on the principle, it should be interpreted as meaning and concept corresponding to the technical idea of the present invention.

Hereinafter, the present invention will be described in detail.

The aggregate form of the CNTs is determined according to the bulk form of the catalyst. When the CNTs have a plate-like catalyst structure, the CNTs grow in a direction perpendicular to the plate to form a bundle of CNTs. It is therefore an object of the present invention to provide a catalyst for the production of bundled CNTs having a well-defined plate shape.

A method for preparing a catalyst for producing CNTs is known in various ways, but in the case of using chemical vapor deposition, coprecipitation and impregnation are representatively known.

The impregnation method refers to a method of obtaining a catalyst precursor in powder form by mixing a metal salt aqueous solution with a support that can be used as a support having micropores, followed by filtration or spray drying. The catalyst precursor in powder form obtained by the impregnation method is also obtained as a catalyst for producing CNT through thermal oxidation or reduction.

The coprecipitation method dissolves the metal salt in an aqueous solution state, and induces precipitation between the metal salts by various changes such as pH or temperature, and the precipitate obtained is subjected to filtration drying or spray drying to obtain a catalyst precursor in powder form. Tell how to get. The catalyst precursor in powder form thus obtained is obtained as a catalyst for producing CNTs through a process such as thermal oxidation or reduction.

In the case of the catalyst for producing CNT obtained by the general coprecipitation method, the primary particle form of the coprecipitation catalyst varies according to the type of the coprecipitation agent, and when the coprecipitation agent is, for example, sodium hydroxide, a precipitate is formed due to rapid pH change. Form agglomerates of, and have a plate-like form when, for example, urea is used as a coprecipitation agent.

However, in the general coprecipitation method, for example, when urea is used as a coprecipitation, precipitates are formed by ammonium ions formed by pyrolysis of urea at 80 ° C. or higher, and ammonium ions are volatilized at a high temperature of 80 ° C. or higher. As a problem, the rate of precipitation formation is too slow, and there is a limit to producing a coprecipitation catalyst having a uniform plate-like structure. Therefore, there is a problem that the CNT obtained therefrom is obtained in a form in which some entangled forms and bundle forms are mixed. In addition, according to the conventional method, since the production of the catalyst takes 24 hours or more, the productivity is lowered.

In the present invention, by introducing a hydrothermal synthesis reaction using a closed reaction system (closed reaction system), to propose a method for effectively producing a plate-shaped catalyst of a uniform form.

In addition, in the present invention, it is possible to control the bundle size, CNT yield, and diameter of the CNTs of the CNTs prepared by using the thickness and size of the plate catalyst.

The catalyst according to one aspect of the present invention may be prepared by the following method using hydrothermal synthesis coprecipitation method:

Adding a metal salt of the catalyst component, a metal salt of the active component, and a coprecipitation agent to an aqueous solvent to obtain an aqueous coprecipitation-containing metal salt solution;

Obtaining a co-precipitated slurry by a hydrothermal synthesis co-precipitation process of heating the co-precipitation-containing metal salt aqueous solution at a temperature of 120 ° C. to 200 ° C .; And

Filtering and drying the slurry.

The method of preparing the coprecipitation catalyst according to the present invention is characterized by using a hydrothermal synthesis coprecipitation method, unlike the conventional coprecipitation method. That is, in the conventional coprecipitation method, a step of forming a slurry-like precipitate by heating a metal aqueous solution and then adding a coprecipitation agent, in the present invention, a coprecipitation agent is simultaneously added to an aqueous solvent together with a metal component serving as a catalyst. After that, it is heated at a higher temperature to form a slurry-like precipitate.

In the manufacturing method according to one embodiment, the hydrothermal coprecipitation process is a coprecipitation-containing metal aqueous solution at a temperature of 120 ℃ to 200 ℃, or 120 ℃ to 180 ℃ about 1 hour to about 10 hours, or about 1 hour to It is made by heating for about 5 hours, or about 2 to 4 hours, it is possible to form a more efficient coprecipitation catalyst for the production of CNT in the above range, if the reaction time is too long the thickness of the catalyst increases There is a fear that the number of catalysts produced is reduced, and if too short, sufficient catalyst yield cannot be obtained.

The coprecipitation agent used in the coprecipitation catalyst can be used without limitation as long as it is used in the art, for example, ammonium hydroxide (NH ₄ OH), ammonium carbonate ((NH ₄ ) ₂ CO ₃ ), ammonium bicarbonate (NH ₄ HCO ₃ ), Urea, etc. can be used 1 or more types, Preferably, urea can be used. By these, coprecipitation of the metal salt can be induced.

In the hydrothermal synthesis coprecipitation process, the coprecipitation may be performed batchwise or continuously. It is also possible to add surface-active substances, for example ionic or nonionic emulsifiers or carboxylic acids, for improving the coprecipitation properties and for surface modification of the catalysts produced.

In the preparation method, the coprecipitation-containing metal salt aqueous solution may be formed by adding a coprecipitation agent and a metal salt to an aqueous solvent, wherein the aqueous solvent may include water or a mixed solvent of water and a lower alcohol. Water is preferable as the aqueous solvent.

As the metal salt to be added to the aqueous solvent, a metal salt of the catalyst component and a metal salt of the active component can be used, and examples of the form of acetate, nitrate, halide (for example chloride or bromide) or other soluble compounds.

As the catalyst component, at least one selected from iron (Fe), nickel (Ni), cobalt (Co), and the like may be used, and iron and cobalt are preferable. They remain in the co-precipitation catalyst to serve as the main catalyst.

As the active ingredient, at least one or more selected from magnesium (Mg), aluminum (Al), molybdenum (Mo), manganese (Mn), chromium (Cr), vanadium (V) and the like may be used, and aluminum and magnesium are preferable. . They serve as carriers and promoters.

The catalyst component and the active ingredient may be used in a weight ratio of 1 to 0.5 to 10, and can exhibit better CNT production activity in this content range.

The metal salts of the catalyst component and the active ingredient are not limited thereto, and the precursor concentration may be included in an amount of 0.05 g / ml to 0.5 g / ml in the aqueous metal solution.

The co-precipitation agent may be used in the range of about 0.3 to 2 equivalents relative to the content of the metal element in the co-precipitation-containing metal aqueous solution. In such a range, sufficient co-precipitation can be induced.

The co-precipitation-containing metal aqueous solution as described above may be hydrothermally synthesized coprecipitation treatment to obtain a co-precipitated slurry, which is separated and dried to prepare a co-precipitation catalyst. The separation process of the slurry can be separated by known methods, such as filtration, centrifugation, evaporation and concentration, of which centrifugation and filtration processes are preferred. The separated coprecipitation catalyst may be further washed or used as is in a separated state. In order to improve the handleability of the obtained coprecipitation catalyst may further comprise the step of drying it. After the drying process, the step of pulverizing the dry matter into smaller particles may also be included.

The coprecipitation catalyst obtained by the above production method may further include a conditioning step if necessary. Such a conditioning process is intended to improve catalytic properties, and may include, in addition to firing and heat treatment, steam treatment. For example, the coprecipitation catalyst obtained in the above process may be heat treated at a temperature of 300 ° C to 1200 ° C and an oxidizing atmosphere. This conditioning process may be performed before or after shaping and / or grading the co-catalyst.

The coprecipitation catalyst obtained by the above production method may have various forms, for example, may have a plate-like structure. As used herein, the term "plate-like" means a small piece of planar structure with a predetermined thickness. For example, the co-catalyst of the plate structure may have a thickness of 1 to 20 nm, the plate diameter is generally 0.5 to 5 ㎛ It may have a range of, and may have a somewhat irregular shape, for example, crushed square or circle shape. In the case of square or irregular shapes, the diameter means the diameter of the circumscribed circle.

According to one embodiment, as the content of the coprecipitation in the catalyst manufacturing process increases, the size of the plate-like structure shows a tendency to decrease, and thus the number of catalysts is increased so that the yield is used when the coprecipitation catalyst for CNT synthesis is used. It is possible to increase the specific surface area and to reduce the size of the bundle shape.

Such a coprecipitation catalyst of the present invention can be used for the synthesis of carbon nanostructures, for example CNTs.

The process for preparing CNTs from the coprecipitation catalysts obtained by the above method includes, but is not limited to:

Injecting a co-precipitation catalyst according to the present invention into a reactor and injecting a carbon source or the carbon source and hydrogen gas, nitrogen gas or a mixture thereof into the reactor at a temperature of about 500 to 900 ° C .; And

Growing CNTs through decomposition of the injected carbon source over the catalyst surface.

According to one embodiment, the reactor may be a fixed bed reactor or a fluidized bed reactor without limitation.

The reaction temperature of the reactor in the CNT manufacturing process may be used in the range of about 500 to 900 ℃, or about 600 ℃ to 800 ℃, it is preferable to use the range of about 600 ℃ to 700 ℃ in terms of CNT production yield. Can be. As shown in the following examples, as the reaction temperature increases, the yield of CNTs increases, and the specific surface area decreases, thereby increasing the diameter of the CNTs.

In addition, the reaction time in the reactor in the CNT manufacturing process may be used in the range of 0.5 to 10 hours, or 1 hour to 5 hours. As demonstrated in the examples below, the CNT specific surface area at reaction times of 1 to 2 hours is similar but decreases beyond 4 hours. Therefore, when the reaction time increases as the reaction temperature increases, coating of amorphous carbon occurs, which may increase the diameter of the CNT.

Therefore, in order to obtain a low diameter CNT having a high specific surface area in the CNT manufacturing process, it is preferable to reduce the reaction time of the reactor or to reduce the reaction temperature.

The CNT of the present invention obtained according to the manufacturing method may be, for example, a bundle type of bulk density of 10 to 50 kg / m ³ .

The term "bulk density" used in the present invention is defined by Equation 1 below, and as the coprecipitation catalyst produced by hydrothermal synthesis is used, the density distribution of CNTs grown therefrom may also have a specific range.

[Equation 1]

Bulk Density = CNT Weight (kg) / CNT Volume (m ³ )

In addition, the CNT obtained by the above production method may have a particle size or an average particle diameter of 50 to 800 µm and a strand diameter of the CNTs of 1 to 50 nm.

The CNT of the present invention can be used as a raw material in the electric field, the electronic field, the energy field, etc., and can also be used as the reinforcing material in the plastic field.

Hereinafter, examples are provided to help the understanding of the present invention, but the following examples are only for exemplifying the present invention, and various changes and modifications can be made within the scope and spirit of the present invention. It will be apparent to those having the invention, and such variations and modifications are within the scope of the appended claims.

Comparative Example 1

Fe (NO ₃ ) ₂ ㆍ 9H ₂ O 5.05 g, Co (NO ₃ ) ₂ ㆍ 6H ₂ O 1.45 g, Al (NO ₃ ) ₃ ㆍ 9H ₂ O 9.325 g, Mg (NO ₃ ) ₂ ㆍ 6H in a 250 mL beaker 11.4 g of ₂ O and 150 mL of distilled water were added and stirred to prepare an aqueous metal salt solution, which was then heated to reach a temperature of 80 ° C. Subsequently, the NaOH aqueous solution dissolved in 10 mL of distilled water was slowly added dropwise to the aqueous metal salt solution with stirring so that the equivalent ratio to the nitrate group was 0.82. After the addition of the NaOH solution, the precipitate was stirred at a temperature of 80 ° C. for 18 hours. After completion of the reaction, the mixture was cooled to room temperature, and the obtained precipitate was filtered and dried in an oven at 120 ° C. for 24 hours to obtain a catalyst powder.

Comparative Example 2

In Comparative Example 1, NaHCO ₃ was used instead of NaOH, and the coprecipitation catalyst was obtained by performing the same process as in Comparative Example 1 except that the heating temperature was changed from 80 ° C. to 110 ° C.

Comparative Example 3

In Comparative Example 1, a co-precipitation catalyst was carried out in the same manner as in Comparative Example 1 except that urea was used instead of NaOH such that the equivalent ratio was 0.87, and the heating temperature was changed from 80 ° C to 110 ° C. Obtained.

SEM images of the coprecipitation catalysts obtained in Comparative Examples 1 to 3 are shown in FIGS. 1 to 3, respectively. Referring to these figures, it can be seen that the shape of the primary particles of the co-precipitation catalyst is different depending on the type of the co-precipitation agent. That is, when NaOH was used as a coprecipitation agent, it had a rounded aggregate shape, and in the case of urea, it showed a plate shape but did not show a perfect plate shape.

Example 1 Preparation of Coprecipitation Catalyst

Fe (NO ₃ ) ₂ ㆍ 9H ₂ O 5.05 g, Co (NO ₃ ) ₂ ㆍ 6H ₂ O 1.45 g, Al (NO ₃ ) ₃ ㆍ 9H ₂ O 9.325 g, Mg (NO ₃ ) ₂ ㆍ 6H in a 250 mL beaker After adding 11.4 g of ₂ O and 150 mL of distilled water, the amount of urea was fixed at an equivalence ratio of 1.34 to the total amount of nitrate ions, and then stirred to prepare a metal salt aqueous solution. This was hydrothermally synthesized at 150 ° C. for the time shown in Table 1 to obtain a precipitate. The precipitate obtained was filtered and dried in an oven at 120 ° C. for 24 hours to obtain a coprecipitation catalyst.

division Hydrothermal synthesis time Urea content compared to nitrate groups (equivalent ratio) Example 1-1 1 hours Urea / NO ₃ ^-: 0.87 Example 1-2 1.5 hours Example 1-3 2 hours Example 1-4 3 hours Example 1-5 6 hours Example 1-6 10 hours Example 1-7 60 hours

SEM images of the coprecipitation catalysts obtained in Examples 1-2, 1-4, 1-6, and 1-7 are shown in FIGS. 4, 5, 6, and 7, respectively. Referring to these figures, it can be seen that as the hydrothermal reaction time increases, the thickness of the plate-shaped structure of the co-precipitation catalyst increases.

Example 2: Preparation of Coprecipitation Catalyst

A coprecipitation catalyst was prepared in the same manner as in Example 1-1 (hydrothermal synthesis time 3 hours) except that the content of urea in Example 1-1 was variously changed as shown in Table 2 below. .

division Nitrate group than the urea content (urea / NO ₃ ^-) Catalyst shape Average Diameter ± Deviation (μm) on Catalyst Plate Example 2-1 0.47 Flower-like shape - Example 2-2 0.63 Flower-like shape + plate > 3 Example 2-3 0.87 Plate 2 ± 0.5 Example 2-4 1.11 Plate 1.3 ± 0.3 Example 2-5 1.34 Plate 1.1 ± 0.3 Example 2-6 1.66 Plate 1 ± 0.3

SEM images of the coprecipitation catalysts obtained in Examples 2-1, 2-2, 2-3, and 2-5 are shown in FIGS. 8, 9, 10, and 11, respectively. Referring to these figures, when the amount of urea is 0.47, the catalyst is present in a plate-like agglomerate in a flower-like shape instead of an independent plate-like form. Increasing the content of urea, 0.63 is a mixture of flower-like and independent plate shapes. Looking at the tendency of the size of the catalyst plate diameter according to the content of urea, it can be seen that as the content of the urea increases, the plate size of the co-precipitation catalyst decreases, thereby increasing the number of catalysts.

Comparative Examples 4 to 6: Preparation of CNTs

CNT synthesis was tested in a laboratory scale fixed bed reactor using the coprecipitation catalyst prepared in Comparative Examples 1 to 3. Specifically, the co-precipitation catalyst prepared in the above process is mounted in the middle of a quartz tube having an inner diameter of 55 mm, and then heated up to 660 ° C. in a nitrogen atmosphere, and maintained therein. (Volume ratio 1: 1) was synthesized for 2 hours while flowing at a flow rate of 60 sccm to synthesize a predetermined amount of CNT aggregates. The CNT yield at this time is shown in Table 3 below.

division CNT yield (CNT g / catalyst g) CNTBET specific surface area (m ² / g) Comparative Example 4 15 170 Comparative Example 5 11 150 Comparative Example 6 19 200

SEM images of the CNTs obtained in Comparative Examples 4, 5 and 6 are shown in FIGS. 12, 13 and 14. Referring to these drawings, when the CNT is manufactured using the coprecipitation catalysts obtained in Comparative Examples 1 to 3, the produced CNTs mostly have an entangled shape, and the coprecipitation catalysts obtained in Comparative Example 3 have some plate-like shapes. Therefore, it can be seen that the CNTs obtained therefrom are mixed in some bundle shapes.

Example 3: CNT Preparation

CNT synthesis was tested in a laboratory scale fixed bed reactor using the coprecipitation catalysts prepared in Examples 1-2 to 1-7. Specifically, the co-precipitation catalyst prepared in the above process is mounted in the middle of a quartz tube having an inner diameter of 55 mm, and then heated up to 660 ° C. in a nitrogen atmosphere, and maintained therein. (Volume ratio 1: 1) was synthesized for 2 hours while flowing at a flow rate of 60 sccm to synthesize a predetermined amount of CNT aggregates. The CNT yield at this time is shown in Table 4, and SEM images of the CNTs obtained in Examples 3-5 and 3-6 are shown in FIGS. 15 and 16, respectively.

division Nitrate group than the urea content (urea / NO ₃ ^-) Co-catalyst Hydrothermal Time CNT yield (CNT g / catalyst g) CNTBET specific surface area (m ² / g) Example 4-1 1.34 1.5 hours 15.8 267.0 Example 4-2 1.34 2 hours 23.3 297.0 Example 4-3 1.34 3 hours 27.2 320.0 Example 4-4 1.34 6 hours 15.5 295.0 Example 4-5 1.34 10 hours 14.1 284.6 Example 4-6 1.34 60 hours 5.2 120.0

As described in Table 4, FIG. 15 and FIG. 16, as the hydrothermal reaction time was increased during the preparation of the coprecipitation catalyst, the yield was decreased and the specific surface area was reduced when synthesizing CNTs using the same. This is due to the decrease in the number of catalysts due to an increase in the plate thickness of the catalyst when the hydrothermal reaction time of the coprecipitation catalyst increases.

From the above results, it can be seen that the hydrothermal reaction time of the coprecipitation catalyst is preferably about 3 hours.

Example 4: CNT Preparation

CNT synthesis was tested in a laboratory scale fixed bed reactor using the coprecipitation catalysts prepared in Examples 2-3, 2-4, 2-5 and 2-6. Specifically, the co-precipitation catalyst prepared in the above process is mounted in the middle of a quartz tube having an inner diameter of 55 mm, and then heated up to 660 ° C. in a nitrogen atmosphere, and maintained therein. (Volume ratio 1: 1) was synthesized for 2 hours while flowing at a flow rate of 60 sccm to synthesize a predetermined amount of CNT aggregates. The CNT yield and BET specific surface area at this time are shown in Table 5 below, and SEM images of CNTs obtained in Examples 4-1, 4-2 and 4-4 are shown in FIGS. 17 to 19, respectively.

division Nitrate group than the urea content (urea / NO ₃ ^-) CNT yield (CNT g / catalyst g) CNTBET specific surface area (m ² / g) Example 4-1 0.63 19.6 230.5 Example 4-2 0.87 21.4 256.8 Example 4-3 1.34 27.2 320.0 Example 4-4 1.66 30.3 261.4

As described in Table 5 and FIGS. 17 to 19, when the urea content was increased in the preparation of the coprecipitation catalyst, the yield was increased, the specific surface area was increased, and the bundle size was decreased when synthesizing CNT using the same. Able to know. This is due to the increase in the number of catalysts due to a decrease in the plate thickness of the catalyst when the urea content of the coprecipitation catalyst increases.

Claims (23)

Adding a metal salt of the catalyst component, a metal salt of the active component, and a coprecipitation agent to an aqueous solvent to obtain an aqueous coprecipitation-containing metal salt solution; Obtaining a co-precipitated slurry by a hydrothermal synthesis co-precipitation process of heating the co-precipitation-containing metal salt aqueous solution at a temperature of 120 ° C. to 200 ° C .; And Method for producing a co-catalyst for producing carbon nanotubes comprising the step of filtering and drying the slurry. The method of claim 1, Method of producing a co-precipitation catalyst is the time of the hydrothermal synthesis coprecipitation step 1 hour to 10 hours. The method of claim 1, The coprecipitation agent is a method of producing a coprecipitation catalyst of at least one of ammonium hydroxide, ammonium carbonate, ammonium bicarbonate and urea. The method of claim 1, Method for producing a co-precipitation catalyst wherein the co-precipitation-containing metal aqueous solution further comprises a surface-active substance. The method of claim 1, The aqueous solvent is a method of producing a co-precipitation catalyst is water or a mixed solvent of water and alcohol. The method of claim 1, Method for producing a co-catalyst is the metal salt is acetate, nitrate or halide. The method of claim 1, The catalyst component is a method for producing a co-precipitation catalyst of at least one of iron, nickel and cobalt. The method of claim 1, The active ingredient is a method for producing a co-precipitation catalyst of at least one of magnesium, aluminum, molybdenum, manganese, chromium and vanadium. The method of claim 1, Method for producing a co-catalyst is a catalyst component and the active ingredient having a weight ratio of 1 to 0.5 to 10. The method of claim 1, Method for producing a co-catalyst is a precursor concentration of the catalyst component and the active ingredient in the aqueous metal solution is 0.05 g / ml to 0.5 g / ml. The method of claim 1, Wherein the coprecipitation agent is in the range of about 0.3 to 2 equivalents relative to the content of the metal element. The method of claim 1, Method for producing a co-precipitation catalyst is the separation process is centrifugation or filtration. The method of claim 1, The coprecipitation catalyst is a method of producing a coprecipitation catalyst having a plate-like structure having a diameter of 0.5 to 5 microns. The method of claim 1, Method for producing a co-precipitation catalyst is a plate-like thickness of 1 to 20 nm. The method of claim 11, The coprecipitation catalyst has a plate-like structure, the size of the plate-like structure decreases as the content of the co-precipitation agent increases. The method of claim 1, Method for producing a co-catalyst is the carbon nanotubes of the bundle type. A coprecipitation catalyst for producing carbon nanotubes obtained by the manufacturing method according to any one of claims 1 to 16. 17. The coprecipitation catalyst obtained by the method according to any one of claims 1 to 16 is introduced into a reactor, and the carbon source or the carbon source and hydrogen gas, nitrogen gas or these are introduced into the reactor at a temperature of 500 to 900 ° C. Injecting a mixed gas; And And growing carbon nanotubes through decomposition of the carbon source injected on the catalyst surface. The method of claim 18, Method of producing a carbon nanotube that the reaction temperature of the reactor is 600 to 700 ℃. The method of claim 18, The reaction time of the reactor is a method of producing carbon nanotubes of 1 hour to 5 hours. Carbon nanotubes obtained by the manufacturing method according to claim 18. The method of claim 21, Carbon nanotubes having a bulk density of 10 to 50 kg / m ³ of the carbon nanotubes. The method of claim 21, Carbon nanotubes are bundle type of carbon nanotubes.

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