CN104773717A - Preparation method of aperture-controllable porous all-carbon structure - Google Patents

Abstract

The invention relates to a preparation method of an aperture-controllable porous all-carbon structure. The method comprises the following steps: putting a first mixture obtained by mixing multi-tube carbon nanotubes with isopropanol according to a mass ratio of 1:5000 in an ultrasonic cleaner, carrying out ultrasonic dispersion at normal temperature to obtain a multi-wall carbon nanotube suspension, putting a second mixture obtained by adding polymer powder with a low thermal decomposition temperature in the ultrasonic cleaner with the frequency of 60kHz, and carrying out ultrasonic dispersion at normal temperature to obtain a multi-wall carbon nanotube/low thermal decomposition temperature polymer powder uniformly mixed liquid; and drying a mixture obtained after filtering out a solvent in the mixed liquid in a tubular heating furnace, carrying out heating thermal decomposition, and naturally cooling to obtain the aperture-controllable porous all-carbon structure. The preparation method has the advantages of simplicity, low device requirements, short production period, high efficiency and low energy consumption. The obtained structure has the advantages of large specific surface area, high amount of porosity, controllable aperture and pore shape, and very high application values in adsorption, separation and filtration fields.

Description

A method for preparing a porous all-carbon structure with controllable pores

technical field

The invention relates to a method for preparing a porous full-carbon structure with controllable pores, and belongs to the technical field of novel carbon material preparation.

Background technique

As a new type of carbon material, the all-carbon porous structure has attracted the attention of researchers due to its special microstructure and excellent physical and chemical properties. The preparation process and performance exploration have always been hot research topics.

At present, the commonly used methods for preparing all-carbon porous structures include sol-gel method, freeze-drying method, vacuum foaming method, template method, etc. On the one hand, these preparation methods involve special conditions such as high temperature and high pressure, which have relatively high requirements for equipment, which directly leads to Its synthesis cost is relatively high. On the other hand, due to the cumbersome intermediate steps, the preparation cycle is long and the efficiency is low. So far, there is no preparation method with simple preparation process, energy saving, environmental protection, high efficiency and low cost.

Contents of the invention

The invention discloses a method for preparing a porous full-carbon structure with controllable pores. Multi-walled carbon nanotubes and polymer powder particles with low thermal decomposition temperature are added to isopropanol to ultrasonically disperse at normal temperature, and finally the low-heat The polymer powder particles at the decomposition temperature are removed to obtain a porous full-carbon structure with controllable pores. The preparation process is simple, the equipment requirements are low, the production cycle is short, the efficiency is high, the energy consumption is low, and the cost is low. The disadvantages of high equipment requirement, high energy consumption, low efficiency, high cost and the like existing in the prior art can be overcome.

Technical solution of the present invention is realized in that way:

A method for preparing a porous full-carbon structure with controllable pores, characterized in that: multi-walled carbon nanotubes are used as a precursor structure, polymer powder particles with a low thermal decomposition temperature are used as a pore-forming agent, and isopropanol is used as a dispersant. Prepare a porous full carbon structure with controllable pores by ultrasonic dispersion, vacuum filtration, and high-temperature calcination; follow the steps below:

A) adding multi-walled carbon nanotubes to isopropanol at a mass ratio of 1:5000 to obtain a first mixture;

B) Place the first mixture in an ultrasonic cleaning machine with a frequency of 60kHz and a power of 400w, and ultrasonically disperse at room temperature for 50 minutes to obtain a uniform dispersion of carbon nanotubes;

C) adding polymer powder with a low thermal decomposition temperature to the dispersion liquid obtained in step B) according to the mass ratio to obtain a second mixture;

D) Place the second mixture in an ultrasonic cleaning machine with a frequency of 60kHz and a power of 400W, and ultrasonically disperse it at room temperature for 20 minutes to obtain a uniform mixture, so that the multi-walled carbon nanotubes and the polymer powder with a low thermal decomposition temperature are uniform Disperse in isopropanol;

E) Pour the homogeneous mixed solution obtained in step D) into a sand core filter device, perform vacuum filtration through filter paper, and obtain a pancake-shaped third mixture on the filter paper after the suction filtration is completed;

F) After drying the pancake-shaped third mixture obtained in step E), put it into a tube furnace and slowly heat up to the thermal decomposition temperature of the polymer powder particles at a low thermal decomposition temperature at a heating rate of 3°C/min in the air. Keep it warm at this temperature for 1-3 hours, cool it down to room temperature, take it out, remove all the polymer powder particles with low thermal decomposition temperature, and get the porous full carbon structure of the final sample with controllable pores.

The polymer powder with low thermal decomposition temperature described in step C) is one of polymethyl methacrylate or chlorinated polyethylene fiber.

The average particle size of the polymer powder with low thermal decomposition temperature in step C) is 2 μm-40 μm.

The addition ratio of the polymer powder with low thermal decomposition temperature described in step C) is: mass ratio 1:2--1:40.

Advantage and positive effect of the present invention:

The preparation method of the porous full-carbon structure with controllable pores provided by the present invention is to add multi-walled carbon nanotubes and polymer powder particles with low thermal decomposition temperature into isopropanol to ultrasonically disperse at normal temperature, and finally reduce the thermal decomposition temperature to The polymer powder particles are removed. The prepared porous all-carbon structure is a new type of carbon material with micropores, mesopores and macropores. The pore structure is controllable, with large specific surface area, large porosity, low density, and good electrical and thermal conductivity. Carriers, gas sensors, adsorption and electrode materials have broad application prospects. The invention not only has simple preparation process, low equipment requirement, short production cycle and high efficiency, but also has the advantages of low energy consumption, low cost and the like.

Description of drawings

Figure 1 is the XRD diffraction pattern of the porous all-carbon structure prepared in [Example 1];

Figure 2 is the SEM image of the porous all-carbon structure with controllable pores prepared in [Example 1].

Detailed ways

Below in conjunction with accompanying drawing and embodiment the present invention is described in detail, but embodiment is not intended to limit the present invention, all adopting the similar method of the present invention and similar variation thereof, all should be included in the protection scope of the present invention.

[Example 1] Multi-walled carbon nanotubes and isopropanol are mixed at a mass ratio of 1:5000 to obtain the first mixture with a total mass of 150.03g, which is placed in an ultrasonic cleaner with a frequency of 60kHz and a power of 400W, at room temperature Under ultrasonic dispersion for 50 minutes, a suspension of multi-walled carbon nanotubes was obtained, and 300 mg of polymethyl methacrylate (PMMA) with an average particle diameter of 2 μm was added to the obtained suspension to obtain a second mixture, and then the second The mixture was placed in an ultrasonic cleaning machine with a frequency of 60 kHz and a power of 400 W, and was ultrasonically dispersed at room temperature for 20 minutes to obtain a homogeneous mixture of multi-walled carbon nanotubes/polymethyl methacrylate. Pour the above-mentioned homogeneous mixture into a sand core filter device, and perform vacuum filtration through filter paper. After the suction filtration, a pancake-shaped third mixture (multi-walled carbon nanotubes/polymethyl methacrylate) is obtained on the filter paper. . Put the pancake-shaped third mixture into a drying oven to dry at a constant temperature of 60° C., and take it out after drying. Put the obtained third mixture into a tube furnace and slowly heat it up to the thermal decomposition temperature of polymethyl methacrylate at a heating rate of 3°C/min in the air, keep it at this temperature for 2 hours, and cool it down to room temperature naturally. , all the polymethyl methacrylate in the third mixture was removed to obtain a porous all-carbon structure with controllable pores in the final sample.

As shown in Figure 1, there are characteristic peaks of carbon nanotubes at 26° and 44°.

It can be seen from Figure 2(a) that the pores of this structure are obvious and uniform, and the diameter of the macropore is about 2 μm, which is equivalent to the particle size of the added polymethyl methacrylate particles.

[Example 2] The first mixture prepared by mixing multi-walled carbon nanotubes and isopropanol at a mass ratio of 1:5000 was placed in an ultrasonic cleaning machine with a frequency of 60 kHz and a power of 400 W, and was ultrasonically dispersed at room temperature for 50 Minutes to obtain a suspension of multi-walled carbon nanotubes, add polymethyl methacrylate (PMMA) to the first mixture at a mass ratio of 1:10 and continue to add polymethylmethacrylate (PMMA) with an average particle size of 27-37 μm to the obtained first mixture Polymethyl methacrylate (PMMA) to obtain the second mixture, continue to place the second mixture in an ultrasonic cleaning machine with a frequency of 60kHz and a power of 400W, and ultrasonically disperse at room temperature for 20 minutes to obtain multi-walled carbon nanotubes/ Polymethyl methacrylate homogeneous mixture. Pour the obtained mixture into a sand core filter device and perform vacuum filtration through filter paper. After suction filtration, a pancake-shaped third mixture (multi-walled carbon nanotubes/polymethyl methacrylate) is obtained on the filter paper. Put the pancake-shaped third mixture into a drying oven to dry at a constant temperature of 60° C., and take it out after drying. Put the obtained third mixture into a tube furnace and slowly heat it up to the thermal decomposition temperature of polymethyl methacrylate at a heating rate of 3°C/min in the air, keep it at this temperature for 2 hours, and cool it down to room temperature naturally. , all the polymethyl methacrylate in the third mixture was removed to obtain the full carbon porous structure of the final sample.

It can be seen from Figure 2(b) that the pores of this structure are obvious and uniform, and the diameter of the macropores is between 27-37 μm, which is equivalent to the particle size of the added polymethyl methacrylate particles.

[Example 3] The first mixture prepared by mixing multi-walled carbon nanotubes and isopropanol at a mass ratio of 1:5000 was placed in an ultrasonic cleaning machine with a frequency of 60 kHz and a power of 400 W, and was ultrasonically dispersed at room temperature for 50 Minutes to obtain a suspension of multi-walled carbon nanotubes, mix polymethyl methacrylate (PMMA) with the first mixture at a mass ratio of 1:30, and add polymethylmethacrylate (PMMA) with an average particle size of 10-27 μm to the obtained suspension methyl acrylate (PMMA) to obtain the second mixture, continue to place the second mixture in an ultrasonic cleaning machine with a frequency of 60kHz and a power of 400W, and ultrasonically disperse it at room temperature for 20 minutes to obtain multi-walled carbon nanotubes/polymethylene Homogeneous mixture of methyl acrylate. Pour the obtained mixture into a sand core filter device and perform vacuum filtration through filter paper. After suction filtration, a pancake-shaped third mixture (multi-walled carbon nanotubes/polymethyl methacrylate) is obtained on the filter paper. Put the pancake-shaped third mixture into a drying oven to dry at a constant temperature of 60° C., and take it out after drying. Put the obtained third mixture into a tube furnace and slowly heat it up to the thermal decomposition temperature of polymethyl methacrylate at a heating rate of 3°C/min in the air, keep it at this temperature for 2 hours, and cool it down to room temperature naturally. , to remove the polymethyl methacrylate to obtain the final sample full carbon porous structure.

It can be seen from Figure 2(c) that the pores of this structure are obvious and uniform, and the diameter of the macropore is about 10-27 μm, which is equivalent to the particle size of the added polymethyl methacrylate particles.

[Example 4] The first mixture prepared by mixing multi-walled carbon nanotubes and isopropanol at a mass ratio of 1:5000 was placed in an ultrasonic cleaning machine with a frequency of 60 kHz and a power of 400 W, and was ultrasonically dispersed at room temperature for 50 Minutes to obtain a suspension of multi-walled carbon nanotubes, chlorinated polyethylene (CPE) fibers were added to the resulting suspension at a mass ratio of 1:5 to obtain a second mixture, and the second mixture was placed at a frequency of 60kHz , in an ultrasonic cleaning machine with a power of 400W, ultrasonically disperse at room temperature for 20 minutes to obtain a uniform mixture of multi-walled carbon nanotubes/chlorinated polyethylene fibers. Pour the obtained mixed solution into a sand core filter device and carry out vacuum filtration through filter paper. After suction filtration, a pancake-shaped third mixture (multi-walled carbon nanotubes/chlorinated polyethylene fibers) is obtained on the filter paper. Put the pancake-shaped third mixture into a drying oven to dry at a constant temperature of 60° C., and take it out after drying. Put the obtained third mixture into a tube furnace and slowly heat it up to the thermal decomposition temperature of chlorinated polyethylene fibers at a heating rate of 3°C/min in the air, keep it warm at this temperature for 2 hours, cool it naturally to room temperature, and take it out. All the chlorinated polyethylene fibers in the third mixture were removed to obtain the full carbon porous structure of the final sample.

It can be seen in Figure 2(d) that the channel-like pores of this structure are obvious, which is equivalent to the shape of the added chlorinated polyethylene fibers.

Claims (4)

1. the preparation method of the full carbon structure of the porous of a control pore, it is characterized in that: adopt multi-walled carbon nano-tubes to construct body as forerunner, the polymer powder particle of low heat decomposition temperature is as pore-forming material, Virahol is as dispersion agent, pass through ultrasonic disperse, vacuum filtration, the method for high-temperature roasting prepares the full carbon structure of porous of control pore; Carry out in accordance with the following steps:

A) with the ratio of mass ratio 1:5000, multi-walled carbon nano-tubes is joined in Virahol and obtain the first mixture;

B) the first mixture being placed on frequency is 60kHz, and power is in the Ultrasonic Cleaners of 400W, and ultrasonic disperse obtains even carbon nanotube dispersion liquid in 50 minutes at normal temperatures;

C) to step B) polymer powder that adds low heat decomposition temperature according to mass ratio in the dispersion liquid that obtains obtains the second mixture;

D) the second mixture being placed into frequency is 60kHz, power is in the Ultrasonic Cleaners of 400W, ultrasonic disperse 20 minutes at normal temperatures, be uniformly mixed liquid, makes the polymer powder of multi-walled carbon nano-tubes and low heat decomposition temperature evenly spread in Virahol;

E) by step D) the Homogeneous phase mixing liquid that obtains pours in core filtration unit, and carry out vacuum filtration by filter paper, on filter paper, after suction filtration terminates, obtain pancake shape the 3rd mixture;

F) by step e) pancake shape the 3rd mixture that obtains puts into tube furnace is slowly warming up to the polymer powder particle of low heat decomposition temperature in atmosphere heat decomposition temperature with the heat-up rate of 3 DEG C/min after drying, be incubated 1-3 hour at this temperature, naturally cool to room temperature to take out, the polymer powder particle of low heat decomposition temperature wherein is all removed, obtains the full carbon structure of porous of final sample control pore.

2. the preparation method of the full carbon structure of porous of a kind of control pore according to claim 1, is characterized in that: step C) described in the polymer powder of low heat decomposition temperature be one in polymethylmethacrylate or chlorinatedpolyethylene fiber.

3. the preparation method of the full carbon structure of porous of a kind of control pore according to claim 1, is characterized in that: step C) described in the polymer powder median size of low heat decomposition temperature be 2 μm ~ 40 μm.

4. the preparation method of the full carbon structure of porous of a kind of control pore according to claim 1, is characterized in that: step C) described in the additional proportion of polymer powder of low heat decomposition temperature be: mass ratio 1:2--1:4.