CN215403106U

CN215403106U - Vacuum reactor for preparing graphene by electrifying carbon powder

Info

Publication number: CN215403106U
Application number: CN202121512306.7U
Authority: CN
Inventors: 不公告发明人
Original assignee: Beijing Saiyintuopu Technology Co ltd
Current assignee: Lv Haigang; Taiyuan Saiyin New Materials Technology Co Ltd
Priority date: 2021-07-05
Filing date: 2021-07-05
Publication date: 2022-01-04
Anticipated expiration: 2031-07-05

Abstract

The utility model provides a vacuum reactor for preparing graphene by electrifying carbon powder, wherein a power supply anode and a power supply cathode are respectively connected with two electrode bars with sealing rings of the reactor, the electrode bars are respectively inserted into a reaction tube from two ends for sealing, the carbon powder is placed in the middle of the reaction tube, the side surface of the reaction tube is connected with a vacuum pump for vacuum pumping, two sections of metal tube linings are respectively embedded into two ends of the reaction tube, and the electrode bars with the sealing rings are tightly contacted with the metal tube linings to achieve the sealing effect. The reactor effectively reduces the friction between the sealing ring and the reaction tube, protects the sealing ring and is convenient for the vacuum reactor to realize automation.

Description

Vacuum reactor for preparing graphene by electrifying carbon powder

Technical Field

The utility model belongs to the field of nano material preparation, and particularly relates to a vacuum reactor for preparing graphene by electrifying carbon powder.

Background

Graphene is a two-dimensional nano material composed of single-layer honeycomb-shaped carbon atoms, is the thinnest, lightest, strongest and hardest material, has excellent electric conduction and heat conduction performance, and is called as the king of new materials. The current large-scale production of graphene is primarily a graphite redox process. In view of the problems of complex process technology, waste liquid treatment and the like, the production cost of the graphene is very high, the price of the graphene powder in the market is high, and the large-scale application of the graphene is limited.

WO2020/051000 (Flash Joule Heating Synthesis Method and Compositions theory) discloses a Method for preparing graphene by electric power Joule Heating Flash evaporation, in which carbon powder such as carbon black, coke or anthracite is put in a quartz tube, large current is applied for less than 1 second, the temperature is as high as 2700 ℃, and the carbon powder is instantly changed into graphene. For the estimation of the power cost, only 2 degrees of electricity are needed for producing 1 kg of graphene, and the power cost is as low as 1 yuan. As the temperature of the carbon powder is increased from 300K to 3000K within 1 second, the gas generated by the volatile matter in the tube is released at high temperature and expands rapidly, so that the carbon powder is sprayed out of the quartz tube along with the gas, and the electric flash reaction can not be carried out normally. Therefore, the electric flash evaporation method needs to place the quartz tube in a vacuum environment, and the carbon powder is slowed down to be carried and sprayed out by reducing the ambient air pressure.

When the whole reaction device is placed in a vacuum cavity, the volume of the vacuum cavity becomes quite large, so that the vacuumizing time is long and the efficiency is low. Particularly, the reaction device is placed in a vacuum chamber, so that the steps of vacuumizing and putting air are needed to add carbon powder and take out graphene every time, and the method is very complicated and is not beneficial to realizing equipment automation.

The two ends of the quartz tube are directly sealed by the electrode bar with the sealing ring to form a small vacuum reactor for preparing graphene by electric flash evaporation, the reactor is small in size, the gas pumping block can directly feed and discharge, and the automation of equipment is very convenient. However, in the operation process of the equipment, the electrode rod with the sealing ring needs to enter and exit the quartz tube once for each electric flash reaction, the wall of the quartz tube is rough, the sealing ring is greatly abraded, and the sealing ring cannot be sealed after entering and exiting for several times and must be replaced. This frequent replacement of the sealing rings greatly limits the automation of the apparatus in vacuum reactors.

Disclosure of Invention

The utility model aims to provide a vacuum reactor with an electrode bar sealing ring which can be used for multiple times without damage when graphene is prepared by carbon powder electric flash evaporation.

In order to achieve the purpose, the utility model adopts the technical scheme that: a vacuum reactor for preparing graphene by electrifying carbon powder structurally comprises: two electrode rods with sealing rings are respectively connected with the anode and the cathode of a power supply, the electrode rods are respectively inserted into the reaction tube and seal the reaction tube from two ends, carbon powder is placed in the middle of the reaction tube, and the side surface of the reaction tube is connected with a vacuum pump for vacuum pumping, and the device is characterized in that: two ends of the reaction tube are respectively embedded into a section of metal tube lining, and the electrode bar with the sealing ring is tightly contacted with the metal tube lining to achieve the sealing effect.

Further, the reaction tube is made of quartz, alumina ceramic, magnesia ceramic, boron nitride ceramic or zirconia ceramic.

Further, the electrode bar is made of copper, tungsten-copper alloy, iron, stainless steel or graphite.

Further, the electrode rod can be provided with 1 to 5 sealing rings.

Furthermore, the embedded metal pipe liner is a stainless steel pipe, an iron pipe or a copper pipe.

The utility model has the beneficial effects that: (1) because the metal pipe lining is embedded in the contact part of the reaction pipe and the sealing ring of the electrode rod, the metal surface is smooth, and the friction with the sealing ring is very small, so that the sealing ring can enter and exit the metal pipe lining without damage for many times. (2) Through the metal tube lining of the reaction tube, the vacuum reactor can be directly fed into the reactor from the outside and push the obtained graphene out to an external collector, so that the automation of equipment is facilitated.

Drawings

FIG. 1 is a diagram of a vacuum reactor apparatus for preparing graphene by an electric flash method according to the present invention.

FIG. 2 is a scanning electron micrograph of graphene prepared according to the present invention.

Fig. 3 is a raman spectrum of graphene prepared according to the present invention.

Detailed Description

The utility model is further described below with reference to the figures and examples.

The experimental methods described in the following examples are all conventional methods unless otherwise specified; the starting materials and materials used, if not specifically required, are commercially available. The power supply used was a 100 kilowatt dc power supply (maximum voltage 200V and maximum current 500A).

Example 1

As shown in figure 1, a carbon powder circular telegram preparation graphite alkene's vacuum reactor, including a DC power supply (1), its positive pole (2) and negative pole (3) connect two upper and lower copper electrodes (4 and 5) respectively, upper and lower copper electrode respectively has two polytetrafluoroethylene sealing washer (6 and 7), the copper electrode inserts quartz capsule (8) as the reaction tube respectively from top to bottom, total length 100mm, internal diameter 8mm, wall thickness 5mm, carbon powder (9) are placed to the centre of quartz capsule, upper and lower copper electrode just in time is pressed the carbon powder in the middle of the quartz capsule, quartz capsule upper portion has gas pocket (10) to be used for the evacuation, stainless steel pipe inside lining (11 and 12) have been imbedded at the upper and lower both ends of quartz capsule, seal through sealing washer (6 and 7) between upper and lower copper electrode (4 and 5) and the stainless steel pipe inside lining (11 and 12).

The use method of the vacuum reactor comprises the following steps: the lower copper electrode (5) was inserted below the reaction tube, 0.1 g of conductive carbon black was charged from above the reactor, and the upper copper electrode (4) was inserted from above and pressed, and the resistance was measured to be about 1 ohm. Then, vacuum is drawn from the air vent (10) of the vacuum chamber to 0.01 atmosphere. A discharging circuit is connected, the voltage is selected to be 200V, the power supply is switched on, discharging is carried out for 500 milliseconds, and strong light is emitted from the quartz tube. After the reaction is finished, the power supply is cut off, gas is put into the quartz tube, the upper copper electrode and the lower copper electrode are withdrawn, and the plastic sealing ring is intact. And pushing the reacted carbon powder out of the lower opening by using an iron rod, and grinding and crushing to obtain black powder. Scanning electron microscopy of these black powders (fig. 2) revealed that a lamellar structure had been produced. The black powders were examined by laser raman spectroscopy to obtain a raman spectrum (fig. 3), in which the G peak indicates the vibration of the graphite sheet, the D peak indicates the size and defect of the graphene sheet, and the 2D peak indicates the number of layers of the graphene. The black powder can be analyzed from a Raman spectrum, and is a graphene nano material with less than 5 layers.

The process is repeated for 1000 times, the polytetrafluoroethylene sealing rings (6 and 7) are not obviously damaged, and the sealing effect is achieved in the operation process. Therefore, the quartz tube with two ends embedded into the stainless steel tube lining protects the sealing ring, reduces the abrasion of the sealing ring, can be repeatedly used for many times, and provides basic conditions for the automation of equipment.

Example 2

The vacuum reactor of example 1 was used, and alumina ceramic, magnesia ceramic, boron nitride ceramic or zirconia ceramic was used to fabricate reaction tubes, the inner diameter and wall thickness of which were the same as those of the quartz tube of example 1, and 0.1 g of conductive carbon black was charged into each of the fabricated reaction tubes to perform an electric flash evaporation reaction. The obtained black powder is tested to obtain a scanning electron micrograph and a Raman spectrogram, the two drawings are basically the same as the embodiment 1, and the prepared graphene material with less than 5 layers is shown.

The process is repeated for 1000 times, the polytetrafluoroethylene sealing ring is not obviously damaged, and the sealing effect is achieved in the operation process. Therefore, quartz, alumina ceramic, magnesia ceramic, boron nitride ceramic or zirconia ceramic can be used as the material of the reaction tube of the high-temperature vacuum reactor for preparing graphene by electric flash evaporation.

Example 3

The copper electrode in example 1 was changed to tungsten, tungsten-copper alloy, iron, stainless steel or graphite, and 5 vacuum reactors for preparing graphene by electrical flash evaporation were respectively fabricated. 0.1 g of conductive carbon black is put into the reactor each time, and the graphene is prepared by electrifying. The scanning electron micrograph and the raman spectrum of the obtained black powder were identical to those of example 1.

The process is repeated for 1000 times, the polytetrafluoroethylene sealing ring is not obviously damaged, and the sealing effect is achieved in the operation process. Therefore, the upper and lower electrodes of the vacuum reactor may be made of copper, tungsten-copper alloy, iron, stainless steel or graphite.

Example 4

In example 1, 2, 3, 4, and 5 sealing rings were mounted on the electrode and the quartz tube, respectively, to manufacture 5 types of vacuum reactors for electric flash evaporation. 0.1 g of conductive carbon black was placed in each case. When the reactor is vacuumized, the vacuum degree of the 5 reactors can reach 0.01 atmospheric pressure normally, and the scanning electron micrograph and the Raman spectrogram of the black powder obtained by discharging are the same as or similar to those of the example 1.

The process is repeated for 1000 times, the polytetrafluoroethylene sealing ring is not obviously damaged, and the sealing effect is achieved in the operation process. Therefore, 1 to 5 sealing rings can realize effective sealing of the vacuum reactor, so that the electric flash evaporation is realized to prepare graphene and generate the graphene. This means that the vacuum reactor can have 1 to 5 seals at the positive or negative electrode, respectively.

Example 5

2 types of vacuum reactors were prepared by electric flash evaporation by changing the stainless steel tube liner in example 1 to an iron tube and a copper tube. 0.1 g of conductive carbon black is put into the reactor each time, and the graphene is prepared by electrifying. The scanning electron micrograph and the raman spectrum of the obtained black powder were identical to those of example 1.

The process is repeated for 1000 times, the polytetrafluoroethylene sealing ring is not obviously damaged, and the sealing effect is achieved in the operation process. Thus, the metal tube liner in which the vacuum reactor is inserted may be a stainless steel tube, an iron tube or a copper tube.

The above description is only an embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes, or direct or indirect applications in other related fields, which are made by the contents of the present specification, are included in the scope of the present invention.

Claims

1. A vacuum reactor for preparing graphene by electrifying carbon powder structurally comprises: two electrode rods with sealing rings are respectively connected with the anode and the cathode of a power supply, the electrode rods are respectively inserted into the reaction tube and seal the reaction tube from two ends, carbon powder is placed in the middle of the reaction tube, and the side surface of the reaction tube is connected with a vacuum pump for vacuum pumping, and the device is characterized in that: two ends of the reaction tube are respectively embedded into a section of metal tube lining, and the electrode bar with the sealing ring is tightly contacted with the metal tube lining to achieve the sealing effect.

2. The vacuum reactor for preparing graphene by electrifying carbon powder as claimed in claim 1, wherein: the reaction tube is made of quartz, alumina ceramic, magnesia ceramic, boron nitride ceramic or zirconia ceramic.

3. The vacuum reactor for preparing graphene by electrifying carbon powder as claimed in claim 1, wherein: the electrode bar is made of copper, tungsten-copper alloy, iron, stainless steel or graphite.

4. The vacuum reactor for preparing graphene by electrifying carbon powder as claimed in claim 1, wherein: the electrode rod can be provided with 1 to 5 sealing rings.

5. The vacuum reactor for preparing graphene by electrifying carbon powder as claimed in claim 1, wherein: the inner lining of the metal pipe is a stainless steel pipe, an iron pipe or a copper pipe.