CN109292763B - Graphene continuous preparation system - Google Patents
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Abstract
The invention provides a graphene continuous preparation system and a preparation systemThe graphene oxide film forming device comprises a reaction unit and an atmosphere control unit, wherein the reaction unit comprises an i-th reaction area and an n-th reaction area which are sequentially connected in the vertical direction, the reaction unit is set to enable graphene oxide containing functional groups and metal impurities and/or non-metal impurities to sequentially undergo the reaction of the i-th reaction area and the n-th reaction area of the reaction unit under the action of gravity, n is a natural number and is not less than 2, and i takes all natural numbers less than n; the atmosphere control unit comprises a temperature control mechanism and a vacuum control mechanism which are matched with each other, wherein the temperature control mechanism is set to control the temperature of the nth reaction zone to be TnAnd controlling the temperature of the i-th reaction zone to be Ti. The method can remove metal and nonmetal impurities in the graphene, simultaneously remove a large number of oxygen-containing functional groups carried by the graphene oxide, and repair the hybridization defect of the graphene oxide.
Description
Technical Field
The invention relates to the technical field of new material preparation, in particular to a graphene continuous preparation system.
Background
In 2004, the physicist anderley of the university of manchester, uk, hom and consutant, norworth schloff, first isolated single-layer graphene from graphite using mechanical exfoliation, and studied its quasi-particle nature, as well as field effect properties. The discovery rapidly initiates a hot research trend of graphene in the world, and the research and application of graphene are developed rapidly in a few years.
Graphene is a two-dimensional honeycomb network structure composed of carbon atoms, and is a planar material composed of a single layer of carbon atoms, which can be directly stripped from graphite. The arrangement of carbon atoms in graphene is the same as that of graphite, the carbon atoms all belong to a compound hexagonal crystal structure, SP2 hybrid orbitals are stacked on a two-dimensional plane, three sigma bonds are formed between each carbon atom and three nearest adjacent carbon atoms, the rest P orbital electrons (pi electrons) are perpendicular to the graphene plane, and the pi bonds with the surrounding carbon atoms form large pi delocalized bonds. Only two atoms with different spatial positions are on the same atomic plane of graphene.
Structurally, graphene is the basic unit of all other carbon nanomaterials. For example, it can be warped into zero-dimensional fullerenes, rolled into one-dimensional carbon nanotubes, and stacked into three-dimensional graphite. The unique structural characteristics endow the graphene with excellent physical, chemical and mechanical properties and the like.
Excellent conductive performance. The graphene structure is very stable. The connection among all atoms in the graphene is very flexible, and when the external mechanical force of a stone is applied, the surface of the carbon atom is bent and deformed, so that the carbon atom does not need to be rearranged to adapt to the external force, and the stability in the structure is also kept. This stable crystal structure gives carbon atoms excellent electrical conductivity. Because electrons in graphene do not scatter due to lattice defects or the introduction of foreign atoms while moving in orbitals. In addition, due to strong interaction force among carbon atoms, even if the carbon atoms around the graphene are collided at normal temperature, the interference of electrons in the graphene is very small. The speed of the electron motion can reach 1/300 of the speed of light, which is far more than the speed of the electron motion in a common conductor.
Excellent mechanical property. Graphene is the highest known strength substance in human beings, is harder than diamond, and has a strength about 100 times higher than the best steel in the world. Theoretical calculation and experimental detection show that the tensile strength and the elastic modulus of the graphene can reach 125GPa and 1100GPa respectively.
Excellent light transmission performance. Both experimental and theoretical results show that the single-layer graphene only absorbs 2.3% of visible light, namely, the light transmittance of the visible light reaches up to 97.7%, and in combination with the excellent conductivity and mechanical properties of the graphene, the graphene can replace the traditional conductive thin film materials such as indium tin oxide and fluorine-doped tin oxide, so that the brittleness characteristic of the traditional conductive thin film can be overcome, and the problems of indium resource shortage and the like can be solved.
The unique performance characteristics enable the graphene to have wide application prospects in the fields of electronic devices (field effect, radio frequency circuits and the like), optical devices (lasers, ultrafast electronic optical devices and the like), quantum effect devices, chemical and biological sensors, composite materials, energy storage materials and devices (super capacitors, lithium ion batteries, fuel cells and the like).
At present, the mainstream graphene preparation method comprises a mechanical stripping method, a redox method, an epitaxial growth method, a chemical vapor deposition method and the like, wherein the redox method is the most commonly used method for industrial production due to the advantages of low cost, simple production equipment, maximum single-time yield, concentrated product layer number, uniform transverse dimension and the like. On one hand, in the process of oxidation intercalation, the crystal structure of the graphene prepared by the redox method is easily damaged, so that the internal defects of the graphene are increased, and the performance of the graphene is greatly influenced; on the other hand, a large amount of metal and nonmetal impurities still exist in the graphene produced by the oxidation-reduction method, which further influences the large-scale development and application of the graphene; on the other hand, the graphene production by the redox method has the problems of large energy consumption, incapability of continuous production and the like in production scale, and can also influence the large-scale production of the graphene.
Disclosure of Invention
In view of the deficiencies in the prior art, it is an object of the present invention to address one or more of the problems in the prior art as set forth above. For example, one of the purposes of the present invention is to provide a system which is low in cost, energy-saving and environment-friendly and can realize continuous preparation of graphene.
In order to achieve the above object, the present invention provides a graphene continuous preparation system, which, in an exemplary embodiment of the graphene continuous preparation system, may include a reaction unit and an atmosphere control unit, wherein the reaction unit includes an i-th reaction region and an n-th reaction region connected in series in a vertical direction, the reaction unit is configured to enable graphene oxide containing a functional group and containing metal impurities and/or non-metal impurities to sequentially undergo a reaction in the i-th reaction region and the n-th reaction region of the reaction unit by gravity, n is a natural number greater than or equal to 2, and i takes all natural numbers less than n; the atmosphere control unit comprises a temperature control mechanism and a vacuum control mechanism which are matched with each other, wherein the temperature control mechanism is set to control the temperature of the nth reaction area to be Tn and the temperature of the ith reaction area to be Ti, wherein Ti = w1. i/n.Tn, w1 is selected from 0.80-1.20, and Tn is more than 1250 ℃; the vacuum control mechanism is arranged to control the pressure of the nth reaction zone to be Pn and the pressure of the ith reaction zone to be Pi, wherein Pi = (P0-Pn) ((1-i/n)), P0 represents 1 standard atmosphere, and Pn is 30 Pa-500 Pa.
In this exemplary embodiment, the preparation system further includes a speed regulating unit, and the speed regulating unit is configured to blow a gas into the reaction unit to control a descending speed of the graphene oxide in the reaction unit.
In the present exemplary embodiment, the reaction unit includes a reaction chamber, and the inside of the reaction chamber is provided with a graphite-based coating.
In an exemplary embodiment of the graphene continuous production system, the production system may include a first reaction unit including an ith reaction zone and a jth reaction zone sequentially connected in a vertical direction, a first atmosphere control unit including a transport mechanism, a second reaction unit, and a second atmosphere control unit, the first reaction unit being configured to enable graphene oxide containing a functional group and containing metallic impurities and/or non-metallic impurities to sequentially undergo a reaction in the ith reaction zone and the jth reaction zone of the first reaction unit by gravity; the first atmosphere control unit comprises a first temperature control mechanism and a first vacuum control mechanism which are matched with each other, wherein the first temperature control mechanism is set to control the temperature of the ith reaction zone to be Ti and the temperature of the jth reaction zone to be Tj; the first vacuum control mechanism is arranged to control the pressure of the ith reaction zone to be Pi and the pressure of the jth reaction zone to be Pj, wherein the Ti = w1. i/n. Tn, Pi = (P0-Pn) · (1-i/n), Tj = k1. j/n. Tn, and Pj = (P0-Pn) · (1-j/n), the i is a natural number which is less than or equal to j, the j is a natural number and is equal to or less than 1, and the w1 and the k1 are selected from 0.80 to 1.20; the second reaction unit comprises an m-th reaction area and an n-th reaction area which are sequentially connected in the vertical direction, and the second reaction unit is arranged to enable a product obtained after the product is subjected to the first reaction unit to sequentially undergo the m-th reaction area and the n-th reaction area of the second reaction unit to react under the action of gravity; the second atmosphere control unit comprises a second temperature control mechanism and a second vacuum control mechanism which are matched with each other, wherein the second temperature control mechanism is set to control the temperature of the mth reaction zone to be Tm and the temperature of the nth reaction zone to be Tn; the second vacuum control mechanism is arranged to control the pressure of the mth reaction zone to be Pm and the pressure of the nth reaction zone to be Pn, wherein Tm = w2. m/n.Tn, Pm = (P0-Pn) ((1-m/n)), m is taken as all natural numbers which are larger than j and smaller than or equal to n, n is a natural number and is larger than or equal to 2, w2 is selected between 0.80 and 1.20, P0 represents 1 standard atmospheric pressure, Tn and Pn are respectively more than 1250 ℃ and 30Pa to 500 Pa; the transportation mechanism is used for transporting the product obtained by the first reaction unit to the j +1 th reaction area of the second reaction unit.
In this exemplary embodiment, the preparation system further includes a speed regulation unit, and the speed regulation unit is configured to blow a gas into the first reaction unit to control a falling speed of the graphene oxide in the first reaction unit, and blow a gas into the second reaction unit to control a falling speed of the product obtained after the first reaction unit.
In the present exemplary embodiment, the first reaction unit includes a first reaction chamber, the second reaction unit includes a second reaction chamber, and the first reaction chamber and the second reaction chamber are each provided with a graphite coating inside.
In the present exemplary embodiment, the transport mechanism may include a vacuum transport member including a gas flow transport member for feeding the product obtained by the first reaction unit to the second reaction unit.
In any of the above exemplary embodiments, the metal impurities may be one or more of iron, manganese, potassium, and sodium, and the non-metal impurities may be one or both of sulfur and silicon.
In any one of the above exemplary embodiments, the carbon-to-oxygen ratio of the graphene oxide may be between 0.5 and 2.0, and the carbon-to-oxygen ratio of the graphene is 18.0 or more.
In any of the above exemplary embodiments, the oxygen-containing functional group may include one or more of a carboxyl group, a hydroxyl group, a carbonyl group, an ether bond, and an epoxy group.
Compared with the prior art, the invention has the beneficial effects that:
(1) according to the system, the graphene oxide is reacted by setting the reaction areas with different temperatures and pressures by utilizing the self gravity action of the graphene (oxide), so that the problem that the graphene oxide is heated unevenly in the reaction process is avoided;
(2) the system provided by the invention utilizes the characteristic of high melting point of graphene, removes metal and nonmetal impurities in the graphene at high temperature under a vacuum condition, simultaneously removes a large amount of oxygen-containing functional groups carried by the graphene oxide, and repairs the SP3 hybridization defect caused by the graphene oxide in the preparation process;
(3) according to the system, the graphite coating is arranged in the reaction chamber, so that secondary pollution caused by contact of the prepared graphene and the container can be avoided;
(4) according to the invention, graphene oxide is reduced by utilizing different temperature areas and pressure areas, the reduction efficiency is high, the continuous production of graphene can be realized, and the prepared graphene has the advantages of low impurity content, few structural defects and excellent comprehensive performance.
Drawings
The above and other objects and features of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings, in which:
fig. 1 shows a schematic view of a graphene continuous preparation system according to an exemplary embodiment of the present invention.
Fig. 2 shows a schematic view of a graphene continuous preparation system according to another exemplary embodiment of the present invention.
Detailed Description
Hereinafter, a graphene continuous production system according to the present invention will be described in detail with reference to the accompanying drawings and exemplary embodiments.
Specifically, in the conventional preparation process for preparing graphene oxide, for example, the graphene oxide prepared by Hummers contains a large amount of metal and/or nonmetal impurities, so that the prepared graphene is impure. In the existing graphene preparation process, particularly, graphene prepared by an oxidation-reduction method contains a large amount of metal and/or nonmetal impurities, and in an oxidation intercalation process, a crystal mechanism of the graphene is easily damaged, so that internal defects of the graphene are increased, and the performance of the graphene is greatly influenced. According to the method, the melting boiling point difference between the graphene and the impurities contained in the graphene is utilized, the proper temperature, pressure and reaction time are controlled in a high-temperature vacuum environment, the graphene oxide is subjected to a reaction zone by virtue of the self gravity of the graphene oxide, the impurities are effectively removed, the SP thin film defect in the graphene oxide can be repaired, the oxygen-containing functional group of the graphene oxide can be removed, and the metal and/or non-metal impurities can be removed from the graphene oxide in a gaseous form, so that the high-purity graphene with higher purity and higher quality can be prepared. And the melting point and the boiling point of impurities can be reduced in a high-temperature heating process under the low pressure condition, so that the requirement of the preparation process on the temperature is reduced, and the effects of energy conservation and compression cost are achieved. In addition, the graphene oxide is pretreated at a lower temperature and a higher pressure, so that the energy consumption can be effectively reduced, and the reduction efficiency is improved.
The present invention provides a graphene continuous production system, which may include a reaction unit and an atmosphere control unit, as shown in fig. 1, in one exemplary embodiment of the continuous production system of the present invention.
The reaction unit comprises n reaction zones which extend in the vertical direction. Taking graphene oxide containing functional groups and containing metal impurities and/or non-metal impurities as a raw material, starting from the 1 st reaction zone of the reaction unit, sequentially passing the graphene oxide through the ith reaction zone of the reaction unit by the action of self gravity until the nth reaction zone finishes the reaction, and collecting the graphene. Wherein n is a natural number and is more than or equal to 2, and i is all natural numbers less than n.
The atmosphere control unit comprises a temperature control mechanism and a vacuum control mechanism which are matched with each other. The temperature control mechanism is used for controlling the temperature of the ith reaction zone to be Ti and controlling the temperature of the nth reaction zone to be Tn. The Ti = w1. i/n.Tn, w1 can be selected from 0.80-1.20. For example, w1 may take the value 0.9. The vacuum control mechanism can control the pressure of the ith reaction zone to be Pi and the pressure of the nth reaction zone to be Pn. The Pi = (P0-Pn) (1-i/n), and P0 represents 1 standard atmospheric pressure.
The Tn can take a value in a range of over 1250 ℃, further, the temperature Tn can be 1700 ℃ to 2800 ℃, and further, the temperature Tn can be 1700 ℃ to 2500 ℃. The pressure Pn may be 30Pa to 500Pa, further, the pressure Pn may be 60Pa to 100Pa, and further, the pressure Pn may be 85Pa to 95 Pa.
In this embodiment, the preparation system may further include a speed regulation unit. Since graphene oxide is subjected to the reaction zone by its own weight. When the height of the reaction zone is set to a fixed value, the reaction time of the graphene oxide in each zone cannot be effectively controlled, which is not favorable for the reaction of the graphene oxide in the reaction zone. Therefore, in order to effectively control the reaction time of the graphene oxide in each reaction zone, it is necessary to control the descending speed of the graphene oxide. The speed regulating unit can be used for blowing inert gas into the reaction zone. When the descending speed of the graphene oxide is too high and the graphene oxide needs to react for a long time in a certain reaction zone, the direction of the blowing gas of the speed regulating unit can be set to be opposite to the descending direction of the graphene oxide, so that the graphene oxide is prevented from falling rapidly. If the graphene oxide falls in an accelerated manner, the reaction time of the graphene oxide in a certain reaction zone is shortened, the direction of the blowing gas of the speed regulating unit is set to be the same as the direction of the falling of the graphene oxide, and the falling of the graphene oxide is accelerated.
In this embodiment, the reaction unit includes a reaction chamber capable of reacting graphene oxide. The reaction chamber can provide a reaction site for graphene oxide. The reaction chamber can be a whole chamber, or can be provided with a plurality of small chambers without partitions at the middle joints. In order to avoid the influence of the material of the reaction chamber on the purity of the graphene, the graphene is prevented from introducing other element impurities due to the material of the reaction chamber. Therefore, the graphite coating can be arranged in the reaction chamber, and the pollution of impurities to graphene can be effectively avoided. Moreover, the melting point of graphite is as high as 3652 ℃, which is far higher than the melting points of common metal impurities and non-metal impurities, and the graphite can be well used for preparing graphene.
In one exemplary embodiment of the continuous graphene production method according to the present invention, as shown in fig. 2, the production system may include a first reaction unit, a first atmosphere control unit, a transport mechanism, a second reaction unit, and a second atmosphere control unit.
The first reaction unit comprises j reaction zones which are vertically arranged. And (3) sequentially passing the oxidized graphene from the 1 st reaction zone of the first reaction unit through the ith reaction zone and the jth reaction zone of the first reaction unit by means of the self gravity of the oxidized graphene, and finally obtaining a product. The graphene oxide may be a graphene oxide containing a functional group and containing metallic impurities and/or non-metallic impurities. The j reaction zones of the first reaction unit are mutually connected and arranged. J is a natural number and is more than or equal to 1, i takes all natural numbers less than or equal to j
The first atmosphere control unit may include a first temperature control mechanism and a first vacuum control mechanism that cooperate with each other. The first temperature control mechanism can respectively control the temperature in the ith reaction zone to be Ti and the temperature in the jth reaction zone to be Tj. The Ti = w1. i/n.Tn, Tj = w1. j/n.Tn, w1 is selected from 0.80-1.20, for example, w1 may be 0.9. The first vacuum control mechanism can control the pressure of the ith reaction zone to be Pi and the pressure of the jth reaction zone to be Pj, wherein Pi = (P0-Pn) ((1-i/n)), Pj = (P0-Pn) ((1-j/n)), and P0 represents 1 standard atmosphere.
The second reaction unit comprises n-m +1 reaction zones which are vertically arranged. And sequentially passing the product obtained by the first reaction unit from the 1 st reaction zone of the second reaction unit through the m-th reaction zone and the n-th reaction zone of the second reaction unit by means of the gravity of the product, and finally obtaining the graphene in the n-th reaction zone. And the reaction zones in the second reaction unit are adjacently connected. n is a natural number and is more than or equal to 2, m is all natural numbers less than or equal to n and is more than j.
The second atmosphere control unit may comprise a second temperature control mechanism and a second vacuum control mechanism cooperating with each other. The second temperature control mechanism can respectively control the temperature in the mth reaction zone to be Tm and the temperature in the nth reaction zone to be Tn. The Tm = w1. i/n.Tn, w1 is selected from 0.80-1.20, for example, w1 may be 0.85. The second vacuum control mechanism can control the pressure of the mth reaction zone to be Pm and the pressure of the nth reaction zone to be Pn, wherein Pm = (P0-Pn) ((1-i/n)), and P0 represents 1 standard atmosphere.
The Tn can be a value in a range of 1250 ℃ or above, and further, the temperature Tn can be 1700 ℃ to 2200 ℃. The pressure Pn may be 30Pa to 500Pa, further, the pressure Pn may be 60Pa to 100Pa, and further, the pressure Pn may be 85Pa to 95 Pa.
The transportation mechanism is used for transporting the product obtained by the first reaction unit to the j +1 th reaction area of the second reaction unit for continuous reaction to obtain the graphene.
In the above, since there may be a long time for the graphene oxide to react in a certain reaction zone during the reaction of the graphene oxide, a longer reaction zone is required. In order to reduce the requirements on the height of the equipment, the entire reaction zone can be divided into multistage reaction units. For example, the reaction zone is divided into a first reaction unit and a second reaction unit which are vertically arranged in parallel, and each reaction unit comprises a plurality of reaction zones with different temperatures and pressures. Of course, the reaction zone can be adjusted to a plurality of parallel reaction units according to the height required by the graphene oxide reaction, and is not limited to the two reaction units.
In this embodiment, in order to adjust the reaction time of the graphene oxide in each reaction zone, the preparation system further includes a speed adjusting unit. The speed regulating unit can be used for blowing air flow into the first reaction unit to control the descending speed of the graphene oxide in the first reaction unit, and blowing gas into the second reaction unit to control the descending speed of a product obtained after the graphene oxide passes through the first reaction unit.
In this embodiment, the first reaction unit includes a first reaction chamber, and the second reaction unit includes a second reaction chamber. Similarly, in order to prevent the prepared graphene from being polluted, the interiors of the first reaction chamber and the second reaction chamber are respectively provided with a graphite coating.
In this embodiment, the transport mechanism comprises an air flow transport member. The gas flow conveying member is used for feeding the product obtained by the first reaction unit into the second reaction unit. For example, the gas flow transport means may be a low vacuum tube in which a gas flow is generated for transporting the products of the reaction of the first reaction unit.
In any of the above embodiments, the metal impurities may include one or a combination of iron, manganese, potassium, sodium, and the like. The non-metallic impurities may include one or a combination of sulfur, silicon, and the like.
In the above, the metal impurities and the nonmetal impurities contained in the graphene oxide are volatilized out in a gaseous state in a high-temperature vacuum environment. At high temperatures, for example, at high temperatures around 2000 ℃, the melting point and boiling point of the metal impurities and non-metal impurities contained in the graphene oxide can be reached to separate from the graphene oxide. Furthermore, the melting point and the boiling point of the metal impurities and the nonmetal impurities can be further reduced under a certain vacuum degree, and the metal impurities and the nonmetal impurities contained in the graphene oxide can be easily removed through the temperature and the vacuum degree set by the method. The types of the metal and non-metal impurities contained in the graphene oxide of the present invention are not limited to the above-described impurities, and may be any other impurities that can be volatilized at the high temperature and in the vacuum environment of the present invention. The content of iron and manganese elements in the graphene prepared by the system can reach less than 20 PPm. In the existing method for preparing graphene, the iron content of the prepared graphene is generally more than 2000PPm, and the preparation method can effectively reduce impurity iron contained in the graphene and can be better used as a conductive additive of a lithium ion battery. The specific surface area of the graphene can reach more than 220m 2/g. For the raw material graphene oxide, the conductivity of the graphene oxide is approximately 0.1S/cm-20S/cm, and after reaction, the conductivity of the prepared graphene can reach 900S/cm-1500S/cm, so that the conductivity is remarkably increased.
In any of the above embodiments, the oxygen-containing functional group in the graphene oxide includes one or more of a carboxyl group, a hydroxyl group, a carbonyl group, an ether bond, and an epoxy group. The oxygen-containing functional group can be decomposed into carbon dioxide and water under the high-temperature and pressure conditions set by the invention, and the oxygen-containing functional group in the graphene oxide can be effectively removed. Theoretically, the functional group can be removed at a temperature of 1000 ℃ and under the vacuum environment of the present invention, but the temperature set by the present invention should be higher than 1250 ℃ because the temperature for removing impurities is high. Of course, the oxygen-containing functional group of the present invention is not limited thereto, and can be decomposed into carbon dioxide and water at the temperature and pressure of the present invention.
In any of the above embodiments, the carbon-to-oxygen ratio contained in the raw material graphene oxide may be between 0.5 and 2.0. The carbon-oxygen ratio can reach 2 at most (C: O =2: 1). After the reaction of the method disclosed by the invention, the carbon-oxygen ratio in the graphene can be increased to more than 18, for example, 20. The oxygen mainly comes from oxygen-containing functional groups in the graphene oxide, and the lower the oxygen content is, the smaller the number of the oxygen-containing functional groups is, the better the performance of the prepared graphene is.
In any of the above embodiments, setting the pressure has the advantage that the graphene oxide containing impurities has lower melting points and boiling points and is easier to volatilize and remove under the pressure. Further, the set pressure intensity can be 60 Pa-100 Pa. The advantage of setting the temperature above 1250 c is that if the temperature is below 1250 c, it is detrimental to the volatilization of the impurities and may not reach the melting and boiling points of some of the impurities. For example, the temperature can be set to 1250 ℃ to 2800 ℃. If the temperature set for the method of the invention is higher than 2800 ℃, the loss of the reaction set may be serious, the energy consumption is large and the cost is high. Further, the temperature can be 1700 ℃ to 2200 ℃. Further, the temperature may be 2200 ℃, since 2200 ℃ is a carbon material graphitization temperature, and is also beneficial to repairing the self-defects of graphene oxide.
In summary, on one hand, the system of the invention utilizes the gravity action of the (oxidized) graphene, and completes the preparation of the graphene by setting the temperature zone and the reaction zones with different pressures, thereby avoiding the problem of uneven heating of the oxidized graphene caused by the container loaded with the oxidized graphene, and also avoiding the secondary pollution of the container to the graphene product; on the other hand, the graphene is prepared under different temperature and pressure regions by utilizing high-temperature vacuum, the characteristic of high melting point of the graphene is fully utilized, metal and nonmetal impurities in the graphene are removed through high temperature under the vacuum condition, a large amount of oxygen-containing functional groups carried by the graphene oxide are removed, and the SP3 hybridization defect caused in the preparation process of the graphene oxide is repaired. The prepared graphene is low in impurity content, few in structural defects and excellent in comprehensive performance; on the other hand, the graphene oxide is reduced by using different temperature areas and pressure areas, the reduction efficiency is high, and the continuous production of the graphene can be realized.
Although the present invention has been described above in connection with exemplary embodiments, it will be apparent to those skilled in the art that various modifications and changes may be made to the exemplary embodiments of the present invention without departing from the spirit and scope of the invention as defined in the appended claims.
Claims (7)
1. A graphene continuous preparation system, comprising a reaction unit and an atmosphere control unit, wherein,
the reaction unit comprises an ith reaction zone and an nth reaction zone which are sequentially connected in the vertical direction, the reaction unit is set to enable graphene oxide containing oxygen-containing functional groups and containing metal impurities and/or nonmetal impurities to sequentially undergo the reaction of the ith reaction zone and the nth reaction zone of the reaction unit under the action of gravity, n is a natural number and is not less than 2, and i is all natural numbers less than n;
the atmosphere control unit comprises a temperature control mechanism and a vacuum control mechanism which are matched with each other, wherein the temperature control mechanism is set to control the temperature of the nth reaction zone to be TnAnd controlling the temperature of the i-th reaction zone to be TiWherein, Ti=w1·i/n·Tn，w1T is selected from 0.80 to 1.20nOver 1250 ℃; the vacuum control mechanism is arranged to control the pressure of the nth reaction zone to be PnAnd controlling the pressure of the ith reaction zone to be PiWherein P isi=(P0-Pn)·(1-i/n)，P0Denotes 1 standard atmospheric pressure, Pn30Pa to 500 Pa;
the preparation system further comprises a speed regulating unit, wherein the speed regulating unit is used for blowing gas into the reaction unit so as to control the descending speed of the graphene oxide in the reaction unit;
the oxygen-containing functional group comprises one or more of a carboxyl group, a hydroxyl group, a carbonyl group, an ether bond and an epoxy group.
2. The graphene continuous preparation system according to claim 1, wherein the reaction unit comprises a reaction chamber, and a graphite coating is disposed inside the reaction chamber.
3. A graphene continuous preparation system is characterized by comprising a first reaction unit, a first atmosphere control unit, a transportation mechanism, a second reaction unit and a second atmosphere control unit,
the first reaction unit comprises an ith reaction zone and a jth reaction zone which are sequentially connected in the vertical direction, and the first reaction unit is arranged to enable graphene oxide containing oxygen-containing functional groups and containing metal impurities and/or nonmetal impurities to sequentially pass through the ith reaction zone and the jth reaction zone of the first reaction unit to react under the action of gravity;
the first atmosphere control unit comprises a first temperature control mechanism and a first vacuum control mechanism which are matched with each other, wherein the first temperature control mechanism is set to be capable of controlling the temperature of the ith reaction zone to be TiAnd controlling the temperature of the jth reaction zone to be Tj(ii) a The first vacuum control mechanism is arranged to control the pressure of the ith reaction zone to be PiAnd controlling the pressure of the j reaction zone to be PjWherein, the T isi=w1·i/n·Tn，Pi=(P0-Pn)·(1-i/n)，Tj=k1·j/n·Tn，Pj=(P0-Pn) (1-j/n), wherein i is all natural numbers less than or equal to j, j is a natural number and is more than or equal to 1, w1And k1All are selected from 0.80 to 1.20;
the second reaction unit comprises an m-th reaction area and an n-th reaction area which are sequentially connected in the vertical direction, and the second reaction unit is arranged to enable a product obtained after the product is subjected to the first reaction unit to sequentially undergo the m-th reaction area and the n-th reaction area of the second reaction unit to react under the action of gravity;
the second atmosphere control unit comprises a second temperature control mechanism and a second vacuum control mechanism which are matched with each other, wherein the second temperature control mechanism is set to control the temperature of the mth reaction zone to be TmAnd controlling the temperature of the nth reaction zone to be Tn(ii) a The second vacuum control mechanism is arranged to control the pressure of the mth reaction zone to be PmAnd controlling the pressure of the n-th reaction zone to be PnWherein, the T ism=w2·m/n·Tn，Pm=(P0-Pn) (1-m/n), said m is greater than j and less than or equal toAll natural numbers equal to n, n is a natural number and n is not less than 2, w2Is selected from 0.80 to 1.20, P0Denotes 1 standard atmospheric pressure, TnAnd PnRespectively at 1250 ℃ or above and 30 Pa-500 Pa;
the transportation mechanism is used for transporting the product obtained by the first reaction unit to the j +1 th reaction area of the second reaction unit;
the preparation system also comprises a speed regulating unit, wherein the speed regulating unit is used for blowing gas into the first reaction unit to control the descending speed of the graphene oxide in the first reaction unit, and blowing air flow into the second reaction unit to control the descending speed of a product obtained after the graphene oxide passes through the first reaction unit;
the oxygen-containing functional group comprises one or more of a carboxyl group, a hydroxyl group, a carbonyl group, an ether bond and an epoxy group.
4. The graphene continuous preparation system according to claim 3, wherein the first reaction unit comprises a first reaction chamber, the second reaction unit comprises a second reaction chamber, and the first reaction chamber and the second reaction chamber are both provided with a graphite coating inside.
5. The continuous graphene production system according to claim 3, wherein the transportation mechanism comprises a gas flow transportation means for feeding the product obtained from the first reaction unit to a second reaction unit.
6. The continuous graphene production system according to claim 1 or 3, wherein the metal impurities are one or more of iron, manganese, potassium and sodium, and the non-metal impurities are one or both of sulfur and silicon.
7. The graphene continuous preparation system according to claim 1 or 3, wherein the carbon-to-oxygen ratio of the graphene oxide is between 0.5 and 2.0, and the carbon-to-oxygen ratio of the graphene is above 18.0.
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| CN206705681U (en) * | 2017-04-18 | 2017-12-05 | 青岛华高墨烯科技股份有限公司 | A kind of continous way graphene microwave reduction stove |
| CN108516537A (en) * | 2018-03-29 | 2018-09-11 | 江苏大学 | A kind of continuous apparatus and method for quickly preparing graphene film on copper foil |
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| CN206705681U (en) * | 2017-04-18 | 2017-12-05 | 青岛华高墨烯科技股份有限公司 | A kind of continous way graphene microwave reduction stove |
| CN108516537A (en) * | 2018-03-29 | 2018-09-11 | 江苏大学 | A kind of continuous apparatus and method for quickly preparing graphene film on copper foil |
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