CN109437162A - A method of producing redox graphene - Google Patents
A method of producing redox graphene Download PDFInfo
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- CN109437162A CN109437162A CN201811493682.9A CN201811493682A CN109437162A CN 109437162 A CN109437162 A CN 109437162A CN 201811493682 A CN201811493682 A CN 201811493682A CN 109437162 A CN109437162 A CN 109437162A
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Abstract
The present invention provides a kind of methods for producing redox graphene.The method includes the steps: it will be combined with foreign ion in functional group and there is the graphene oxide of first number of plies, complexing agent to mix with acid solution, obtain mixed liquor；Ultrasonic vibration removes foreign ion and in conjunction with complexing agent；Filtering, obtains graphene oxide after purification；It graphene oxide will be dispersed in water after purification to form hydrogel；Hydrogel is placed at the first temperature and the first pressure, is obtained with the second number of plies graphene oxide, second number of plies is less than first number of plies；Obtained graphene oxide is placed in inert atmosphere；Graphene oxide is brought rapidly up to 500 DEG C or more by microwave and light wave irradiation, obtains redox graphene.The beneficial effect comprise that the completeness of graphene oxide purifying can be effectively improved；Freeze-dried graphene oxide layer interlamellar spacing is big, and the number of plies is few；Heating speed during light microwave reduction is fast, homogeneous heating, and reduction efficiency is high.
Description
Technical field
The present invention relates to the preparation fields of redox graphene, it relates in particular to a kind of production reduction-oxidation graphite
The method of alkene.
Background technique
At the beginning of 21 century, there is this material of nano graphite flakes in scientific circles.2006, Britain The University of
The method that two scientists of Manchester are by mechanically pulling off dexterously is prepared for mono-layer graphite, to formally open stone
Therefore the veil of black this material of alkene, two people also obtain Nobel Prize in physics in 2010.Ideal grapheme material has
Mono-layer graphite is constituted, and passes through sp between carbon atom and carbon atom2Hybridized orbit is connected, and forms stable hexatomic ring knot
Structure.The study found that grapheme material has good various physicochemical properties.Such as: than metallic gold, better electronics is led
The general character, mechanical strength more better than steel, the specific surface area of super large, good optical property, superconduction etc..In view of these special property
Matter, grapheme material military affairs, traffic, in terms of have huge application potential.
In the industrial production, graphene oxide powder can be produced on a large scale using oxidation graft process.It is raw to aoxidize graft process
In the graphene oxide slurry of production contain a large amount of foreign ion, existing graphene oxide there are efficiency in purification process
It is low, the problems such as washing effect is poor；The number of plies is also more in the graphene oxide of production, that is, the graphene oxide quality produced is not
It is high.
Moreover, mostly using chemical reagent to restore (such as sodium borohydride, iodine greatly on the market at present because of the characteristic of graphene oxide
Change hydrogen, the chemical reducing agents such as ascorbic acid), high temperature thermal reduction, plasma method etc..Existing graphene oxide restoring method
It is had the problem that in process of production first is that restored using chemical reagent, needs to use a large amount of chemical reagent, bring pair
Product increases, and subsequent cleaning difficulty increases, and environmentally friendly risk increases, and leads to increased costs；Second is that heat-treating using high temperature, stone is aoxidized
Black alkene reduction temperature is higher, and the uniform in quality that different reduction temperatures obtains not can guarantee, while also bring along product
The problems such as ash content increases, equipment seriously corroded；Third is that using other restoring method (such as plasma), technology difficulties, at
This can be multiplied, and be unable to get industrialization large-scale application.
Summary of the invention
For the deficiencies in the prior art, it is an object of the invention to solve above-mentioned one existing in the prior art
Or multiple problems.For example, one of the objects of the present invention is to provide a kind of method for producing redox graphene, the method
Prepare the redox graphene that impurity content is few, the number of plies is few.
To achieve the goals above, one aspect of the present invention provides a kind of method for producing redox graphene.It is described
Method, which can comprise the following steps that, will be combined with foreign ion and with graphene oxide, the complexing agent of first number of plies in functional group
It is mixed with acid solution, forms mixed liquor, wherein first number of plies is ten several layers to tens of layers；The mixed liquor is carried out
Ultrasonic vibration so that graphene oxide combined foreign ion removing and with complexing agent stable bond；Filtering, obtains after purification
Graphene oxide；Graphene oxide after purification is dispersed in water, and forms graphene oxide hydrogel；By graphite oxide
Alkene hydrogel is placed at the first temperature and the first pressure, so that the hydrone in graphene oxide hydrogel congeals into ice molecule simultaneously
It sublimates, to obtain the graphene oxide with second number of plies, second number of plies is less than first number of plies, first temperature
Degree for not higher than -50 DEG C and temperature change is no more than ± 4 DEG C, first pressure be lower than 1 atmospheric pressure and pressure change not
More than ± 100Pa；Graphene oxide with second number of plies is placed in inert atmosphere；Make to have by microwave and light wave irradiation
The graphene oxide of second number of plies is brought rapidly up to 500 DEG C or more, to decompose its band functional group, institute and reduce its number of plies, is gone back
Former graphene oxide, wherein microwave can be in a manner of traveling wave through the graphene oxide with second number of plies.
An exemplary embodiment according to the present invention, the foreign ion that the graphene oxide is combined may include metal
Foreign ion, such as may include Mn2+、K+And Fe3+At least one of.
An exemplary embodiment according to the present invention is combined in the graphene oxide of foreign ion in the functional group
The weight percent content of the foreign ion be 0.01~1%, such as 0.1%.
An exemplary embodiment according to the present invention, the weight percent of foreign ion in the graphene oxide after purification
Than for not higher than 0.01%.
An exemplary embodiment according to the present invention, the additional amount of the complexing agent are that can be complexed instead with foreign ion
1.0~1.2 times of the theoretical amount answered.
An exemplary embodiment according to the present invention, the acid solution include that concentration is 0.005~0.02mol/L
The sulfuric acid solution that hydrochloric acid solution or concentration are 0.01~0.04mol/L.
An exemplary embodiment according to the present invention, the pH of the acid solution are 0.1~6.
An exemplary embodiment according to the present invention, the filtration step include being filtered by filter membrane, and can
In the lower section of filter membrane, setting filters mechanism to carry out decompression suction filtration.
An exemplary embodiment according to the present invention, the pressure range for filtering decompression can be 10~100Pa.
An exemplary embodiment according to the present invention, when the progress ultrasonic vibration, the frequency of ultrasonic wave is 50~
750Hz。
An exemplary embodiment according to the present invention, first number of plies can be 20~30 layers, and second number of plies can
It is 5~7 layers.
An exemplary embodiment according to the present invention, first temperature can select within the scope of -55~-65 DEG C and temperature
Degree variation is no more than ± 2 DEG C.
An exemplary embodiment according to the present invention, first pressure can be selected in the range of 10~100Pa and
Pressure change is no more than ± 10Pa.
An exemplary embodiment according to the present invention, the solid content of the graphene oxide hydrogel can for 0.1~
50wt%.
An exemplary embodiment according to the present invention, it is described that the graphene oxide with second number of plies is placed in indifferent gas
Step in atmosphere can include: the graphene oxide with second number of plies is sent by inside by gas and is full of nitrogen or inert gas
Tubular container in；Wherein, the both ends of the tubular container have opening, and the gas can be from an opening of tubular container
It flows into, the gas includes nitrogen or inert gas.
An exemplary embodiment according to the present invention, the method, which may further comprise the step of:, is obtaining reduction-oxidation graphite
After alkene, redox graphene is taken out from another opening of tubular container by way of suction filtration.
An exemplary embodiment according to the present invention, flow velocity of the gas in the tubular container can be in 10cm3/
S is hereinafter, such as 1~8cm3/s；The amount that the gas can be sent into graphene oxide can be in 1g/cm3Hereinafter, such as 0.5 ±
0.3g/cm3。
The irradiation time of an exemplary embodiment according to the present invention, the light wave and microwave can be in 10min hereinafter, example
Such as 5 ± 3min.
An exemplary embodiment according to the present invention, the direction and the gas of the microwave and light wave irradiation are in tubulose
Flow direction can be mutually perpendicular in container.
An exemplary embodiment according to the present invention, the vacuum degree in the tubular container can be in 100Pa or less.
An exemplary embodiment according to the present invention, the tubular container may include quartz ampoule, the microwave and light wave
It can be through quartzy tube wall irradiation oxidation graphene.
An exemplary embodiment according to the present invention, the light wave may include infrared ray or far infrared.
An exemplary embodiment according to the present invention, the method may further comprise the step of: to the obtained oxygen reduction
Graphite alkene carries out cooling, dry.
Compared with prior art, the beneficial effect comprise that can effectively make graphene oxide and foreign ion
The completeness of graphene oxide purifying can be improved in separation；The purification efficiency of graphene oxide is high, at low cost.It was freeze-dried
Cheng Buhui destroys the structure of oxidized graphite flake layer after purification, can preferably save functional group, it is freeze-dried after oxidation stone
Ink is not susceptible to agglomeration.Freeze-dried graphene oxide layer interlamellar spacing is greater than the oxygen after the drying of other drying means
Graphite alkene product has superior dispersion performance, the less number of plies and bigger specific surface area；During light microwave reduction
Heating speed is fast, homogeneous heating, no thermal inertia is energy-efficient, and reduction efficiency is high, and can be realized to graphene oxide
Selective oxidation.
Detailed description of the invention
By the description carried out with reference to the accompanying drawing, above and other purpose of the invention and feature will become more clear
Chu, in which:
Fig. 1 shows the process signal for the method that redox graphene is produced in an illustrative embodiment of the invention
Figure.
Fig. 2 shows microwave, optical wavelength radiation system and the tubular container positions in an illustrative embodiment of the invention to close
One schematic diagram of system.
Main marginal data:
1- quartz ampoule；2- optical wave tube；3- microwave cavity.
Specific embodiment
Hereinafter, production redox graphene of the invention will be described in detail in conjunction with attached drawing and exemplary embodiment
Method.
Prepare graphene can using graphene oxide as raw material, and be often combined in graphene oxide impurity from
Son, this results in the purity of graphene oxide not high, and higher impurity content is often had in the graphene produced；And oxygen
The number of plies of graphite alkene is more, and interlayer spacing is small, and it is not very excellent that this, which results in the graphene oxide quality produced,.It is existing
Heat in link in redox graphene frequently with traditional heating method, and traditional heating method be by heat transfer,
Convection current, heat radiation etc. first transfer heat to body surface, then gradually increase core body temperature by heat transfer, it will make
Centre reaches required temperature, needs certain heat conduction time, and just to the time needed for the object of pyroconductivity difference
It is longer.
For this purpose, the invention proposes a kind of methods for producing redox graphene.Fig. 1 shows an example of the present invention
Property embodiment in produce redox graphene method a flow diagram.Fig. 2 shows an example of the present invention
One schematic diagram of microwave, optical wavelength radiation system and tubular container positional relationship in embodiment.
In an exemplary embodiment of the present invention, the method for the production redox graphene may include following step
It is rapid:
Complexing agent, acid solution are mixed with graphene oxide, form mixed liquor, step S01 as shown in figure 1.Wherein, oxygen
It is combined with foreign ion in the functional group of graphite alkene and there is first number of plies.First number of plies is ten several layers to tens of layers,
For example, 20~30 layers.The foreign ion combined in the functional group of graphene oxide may include Mn2+、K+And Fe3+In at least one
Kind.
Ultrasonic vibration is carried out to the mixed liquor, so that the foreign ion removing that graphene oxide is combined and and complexing agent
Stable bond, step S02 as shown in figure 1.Under the action of having children outside the state plan wave, the foreign ion in conjunction with graphene oxide can be de- with it
It is combined from and with the better complexing agent of associativity, simultaneously because the effect of ultrasound, graphene oxide can preferably disperse simultaneously
With H+In conjunction with, will not to complexing agent fight for metal ion.
Filtering, obtains graphene oxide after purification, step S03 as shown in figure 1.
Graphene oxide after purification is dispersed in water, and forms graphene oxide hydrogel, as shown in figure 1 the step of
S04.In dispersion process, dispersion effect is further preferably strengthened by ultrasonic disperse, to make hydrone well into oxygen
In the lamellar structure of graphite alkene perhaps the functional groups in fold or with surface of graphene oxide at hydrated ion, shape
At graphene oxide hydrogel.Graphene oxide hydrogel has to be tied in the lamella or fold of the graphene oxide of its own
Conjunction has structure of water molecules.The solid content of graphene oxide hydrogel can be 0.1~50wt%.For dispersing graphene oxide
Water be preferably secondary deionized water.
Cryogenic vacuum freeze-drying is carried out to graphene oxide hydrogel, obtains the graphene oxide with second number of plies,
Step S05 as shown in figure 1.Wherein, graphene oxide hydrogel can be placed at the first temperature and the first pressure, so that oxidation stone
Hydrone in black alkene hydrogel, which congeals into ice, molecule and sublimates, to obtain the graphene oxide with second number of plies.Also,
First temperature is controlled as not higher than -50 DEG C and the temperature change of the first temperature is no more than ± 4 DEG C always, and the first pressure is controlled
It is no more than ± 100Pa always for the variation lower than 1 atmospheric pressure and the first pressure.Further, the first temperature can be -55
It is selected within the scope of~-65 DEG C and temperature change is no more than ± 2 DEG C.First pressure can be selected in the range of 10~100Pa and
Pressure change is no more than ± 10Pa.Second number of plies is less than first number of plies.Second number of plies is less than the first layer
Number.Second number of plies can have compared to first number of plies to significantly decrease.Here, second number of plies can be the 1/3~1/ of first number of plies
6.For example, second number of plies can be 5~7 layers.
Graphene oxide with second number of plies is placed in inert atmosphere, step S06 as shown in figure 1.For example, can by institute
The graphene oxide with second number of plies is stated to be sent into the container full of nitrogen or inert gas.Wherein, the container may include
Both ends have the tubular container of opening.Further, it may include the tubulose appearance of horizontal cross setting and left and right ends with opening
Device.
It is irradiated by microwave and light wave, is brought rapidly up the graphene oxide with second number of plies to 500 DEG C or more,
To decompose its band functional group, institute and reduce its number of plies, redox graphene is obtained (after restoring to graphene oxide
Product), step S07 as shown in figure 1.Wherein, microwave can penetrate graphene oxide in a manner of traveling wave, and the present invention passes through micro-
Wave one-way transmission forms the traveling-wave waveform constantly transmitted, this can be avoided that localized hyperthermia's phenomenon caused by standing wave effect, energy
Enough improve graphene oxide uniformity for the treatment of.The frequency of microwave can be able to be further 800MHz for 300MHz~300GHz
~250GHz.The frequency of the light wave can be 3 × 1011~3.8 × 1014Hz can be further 2 × 1012~2.5 ×
1014Hz.By acting on while microwave and light wave, graphene oxide can be brought rapidly up to 500 degree or more, band functional group, institute
Can decompose rapidly, by its institute band functional group be oxygen-containing functional group, can decompose instantaneously generate a large amount of gas, as vapor,
Carbon dioxide etc. generates, and gas expands between graphene oxide layer, the number of plies for the material being prepared can be made less, compare table
Area is bigger.Further, microwave and light wave can make the temperature of graphene oxide rise to 500~1000 DEG C, such as 800 ±
150℃.The main heating source of heating process can be microwave, and light wave can play the role of auxiliary, and the two joins together to make
The graphene oxide temperature being heated increases rapidly, is conducive to its deoxidation treatment.
In the present embodiment, as the number of plies of the graphene oxide of raw material can be more than tens of layers, such as 30~50.Low temperature
It is cold it is dry after the number of plies of graphene oxide can be for 10 layers hereinafter, such as 6~8 layers.
Since the number of plies through light microwave reduction object is low, the number of plies of the redox graphene reacted can be lower, example
Such as at 4 layers hereinafter, even 3 layers or less.
By the purifying, the foreign ion on graphene oxide can be removed sufficiently, and removal efficiency can be 99% or more.It is micro- through light
After wave reduction, functional group also can adequately be removed on graphene oxide, and removal efficiency can be to 85% or more, such as 95%.
In the present embodiment, the graphene oxide that foreign ion is combined in the functional group can be by aoxidizing graft process
It obtains, the weight percent content of the foreign ion in graphene oxide functional group can be 0.01~1%, such as 0.1%.
In the present embodiment, raw material used can also be slurry, such as aoxidize graphene oxide slurry made from graft process,
It also is incorporated with foreign ion in graphene oxide functional group in slurry and there is first number of plies.
The content of graphene oxide can be 0.01~100g/L, the quality of foreign ion on graphene oxide in the slurry
Accounting can be 0.01~1%.The additional amount of the complexing agent be can with the 1.0 of the theoretical amount of foreign ion complex reaction~
1.2 again.
In the present embodiment, the graphene oxide containing functional group and containing impurity can also be prepared by the following method
It obtains:
Weighing weight ratio is that 0.8~1.2:0.4~0.6:2~4 graphite, potassium nitrate and potassium permanganate uniformly mix, and is added
Enter the concentrated sulfuric acid, obtains the first mixture.Further, the mass ratio of the graphite, potassium nitrate and potassium permanganate can be 0.85
~1.1:0.4~0.6:2~3, for example, the mass ratio of graphite, potassium nitrate and potassium permanganate can be 1:0.5:3.The dense sulphur
The additional amount of acid can be empirical value, such as the corresponding concentrated sulfuric acid that 115mL~3450mL 98% is added of graphite of 5g~150g.
The graphite can be one of expanded graphite or crystalline flake graphite.
First mixture is subjected to oxygen under 0 DEG C~4 DEG C, 35 DEG C~45 DEG C and 80 DEG C~100 DEG C three temperature sections respectively
Change processing, obtains the second mixture.First mixture needs to undergo three constant temperature oxidation times of low, medium and high temperature
Section.It can be 3h~40h described 0 DEG C~4 DEG C of reaction time, can be 2h~6h 35 DEG C~45 DEG C of reaction time,
It can be 5min~15min 80 DEG C~100 DEG C of reaction time.The oxidant can be hydrogen peroxide.Certainly, the present invention exists
The time reacted under above-mentioned each temperature section is without being limited thereto, can be adjusted according to real reaction situation.
Oxidant is added in the second mixture to be aoxidized, pickling, washing is obtained containing functional group and containing impurity
Graphene oxide.The oxidant can be hydrogen peroxide.
In the present embodiment, complexing agent may include citric acid, sodium citrate, sodium thiosulfate, sodium sulfite, ethylenediamine tetraacetic
Sodium acetate, polyacrylic acid, sodium gluconate or sodium alginate.
The additional amount of the complexing agent is can be with 1.0~1.2 times of the theoretical amount of foreign ion complex reaction.
In the present embodiment, liquid reactions environment needed for the acid solution is capable of providing reaction.Acid solution can wrap
The hydrochloric acid solution that concentration is 0.005~0.02mol/L or the dilution heat of sulfuric acid that concentration is 0.01~0.04mol/L are included, further
Ground, dilute hydrochloric acid concentration can be 0.01mol/L, and dilute sulfuric acid concentration can be 0.02mol/L.
Further, acid solution may include dilute hydrochloric acid solution, this is because the graphene oxide of intercalation oxidizing process preparation
A certain amount of sulfuric acid can be contained in ontology, can faster clean graphene oxide using dilute hydrochloric acid.
In the present embodiment, when carrying out ultrasonic vibration, the frequency of ultrasonic wave can be 50~750Hz, the ultrasound of the range
Frequency can be such that the foreign ion in graphene oxide functional group preferably removes.
The time of ultrasonic vibration is very short, such as can be within 2min, this makes it possible to be detached from foreign ion, and will not
The structure (such as size etc.) of graphene oxide is had an impact.
In the present embodiment, purified, the removal rate of impurity is up to 99% or more, such as the purifying on graphene oxide
The weight percent of the foreign ion of graphene oxide can be not higher than 0.01% afterwards.
In the present embodiment, it can be filtered by filter membrane, so as to graphene oxide after purification and include impurity
Molten liquid phase separation.Wherein, graphene oxide stays on filter layer, and the solution containing impurity can penetrate filter membrane.The mistake
Filter membrane may include polycarbonate membrane (i.e. PC film).
Also pressure-reduction filter device can be set in the lower section of filter layer, so that the solution containing impurity is preferably through filtering
Layer.Wherein, it can realize that decompression filters by the way that vacuum pump is arranged under filter membrane.The pressure range for filtering decompression can be 10~
100Pa。
In the present embodiment, when being filtered using filter membrane, the method may further comprise the step of: on filter membrane
Buffer protection layer, influence of the ultrasonic wave to filter membrane when absorbing and buffer ultrasonic vibration are set.Buffer protection layer can absorb
It is ultrasonically treated remaining energy, to reduce damage of the ultrasonic energy to filter layer, for example, when filter element is polycarbonate membrane
When (i.e. PC film), superfluous ultrasonic energy can damage it.The buffer protection layer may include sponge, the thickness of sponge
It can be 1~100cm.
In the present embodiment, the method may further comprise the step of: to the graphene oxide after purification detected from
Sub- Concentration Testing, to determine whether graphene oxide also needs to continue to purify.Wherein, ICP (Inductively can be passed through
Coupled Plasma, inductively coupled plasma) ion concentration detector detected.
In the present embodiment, the appearance of graphene oxide hydrogel can will be contained with by transport mechanism (for example, crawler belt)
Device (for example, crucible) is sent in low-temp low-pressure cooling device, to realize to the solidifying of the hydrone in graphene oxide hydrogel
It ties and sublimates, to complete to obtain that there is desired low layer number oxygen to the cooling drying of the low-temp low-pressure of graphene oxide hydrogel
Graphite alkene.
In the present embodiment, in cold dry step, by by the control of the first temperature for not higher than -50 DEG C and by the first pressure
Control is not higher than 1 standard atmospheric pressure, and hydrone can be made to become ice molecule, by volume expansion, further widen stone
The lamellar structure of ink；And ice can sublimate volatilization under low-temp low-pressure, and temperature is low, and " entropy " value is low, enables to graphene oxide
The structure being softened is maintained, and makes graphene oxide composite material good dispersion, the large specific surface area of preparation.Moreover, by opposite
Constant cryogenic temperature (for example, not higher than -50 DEG C and controlling the intracorporal temperature change of chamber of entire cold dry chamber no more than ± 4 DEG C)
With relative constant vacuum degree (for example, lower than 1 atmospheric pressure and the entire intracorporal pressure change of chamber of control be no more than ±
100Pa), be conducive to keep the rate of set of hydrone and degree relatively stable, therefore, to " strutting " effect of graphene oxide layer
Stablize；And be conducive to make ice molecule sublimate speed and degree it is relatively stable, therefore, be also beneficial to be avoided to a certain degree because of oxygen
Local defect caused by the local stress of graphite alkene layer.Further say, it will be cold dry by control temperature unit and pressure control unit
The control climate of chamber is temperature within the scope of -55~-65 DEG C and the entire intracorporal temperature change of chamber of control is no more than ± 2 DEG C, with
And pressure control is in 10~100Pa and the entire intracorporal pressure change of chamber of control is no more than ± 10Pa, is more conducive to making moisture
The rate of set and degree of son are further stablized, thus to " the strutting " of graphene oxide layer " effect stability；And be conducive to make
Ice molecule sublimate speed and degree is further stablized, to be also beneficial to further avoid to answer because of the part of graphene oxide layer
Local defect caused by power.
In the present embodiment, the graphene oxide with second number of plies can be sent into tubular container by air-flow.?
Obtained redox graphene can be sent out into tubular container by air-flow.It in other words, can be in an opening of tubular container
It is passed through the air-flow that load has graphene oxide；The air-flow can carry the cavity that (or promotion) material flows through tubular container；?
In flow process, graphene oxide can be reduced to redox graphene；Final air-flow load (or promotion) reduction-oxidation
Another opening outflow of graphene from tubular container.Gas in the air-flow may include nitrogen or inert gas.
Wherein, flow velocity of the gas in pipe container can be 10cm3/ s is hereinafter, can make graphene oxide can smoothly enter into pipe
In shape container, so that it is sufficiently restored by microwave.Further, gas flow rate can be 0.01~8cm3/ s, still further, can
For 2~5cm3/s。
The amount of the graphene oxide of load (or carrying) can be 10g/cm on the air-flow3Hereinafter, such as 0.1~10g/
cm3, can be 2~10g/cm further3。
For above-mentioned graphene oxide, the power of the light wave can be 200~500W, and the power of the microwave can be
500~5500W, such as 2000W.Light wave is identical with the processing time of microwave, can be controlled in 10mim hereinafter, may be, for example, 30s,
2min or 7min etc..
In the present embodiment, the present invention can be realized by the time of the power of light microwave, processing to graphene oxide
Selective oxidation, the redox graphene of different oxygen content can be obtained according to demand.
In the present embodiment, the direction of the microwave and light wave irradiation can be mutually perpendicular to the direction of the air-flow.In this way
Light wave and microwave can be enable preferably to penetrate graphene oxide, sufficiently irradiate, avoid because volume of material becomes larger cause it is micro-
Wave reflection, and then influence the irradiation of deep layer particle.
In the present embodiment, the tubular container may include being horizontally installed on quartz ampoule.Quartz ampoule be it is transparent, will not be every
The uninterrupted characteristic for penetrating effect, having to light wave, microwave of exhausted light and microwave, i.e., the described microwave and light wave can penetrate stone
English tube wall irradiates the graphene oxide.Quartz ampoule high temperature resistant, thermal expansion coefficient are extremely low, chemical stability is fabulous, electrical isolation
Property is excellent, microwave is permeable high.Quartz ampoule of the invention can high temperature resistant, rapid heat cycle can be born；It can bear positive and negative
Pressure is greater than the impact of 1Mpa.
In the present embodiment, the method may further comprise the step of: after obtaining redox graphene, pass through suction filtration
Mode takes out redox graphene from another opening of tubular container.After suction filtration, the method also includes steps
It is rapid: and redox graphene can be separated with gas, the gas isolated is recyclable to be recycled.
In the present embodiment, the present invention can emit microwave by microwave system, and microwave system may include microwave source, microwave
Resonant cavity and microwave anti-leakage mechanism composition.Wherein, microwave source is the electronic device for generating microwave energy, can be by magnetron, high pressure
The devices compositions such as transformer, high-voltage rectifying circuit, cooling fan, overcurrent protection, abnormal temperature protection and waveguide.Microwave resonance
Chamber is the bulk storage containers of microwave energy and the main region of microwave bulking reaction.Anti-leakage mechanism can prevent microwave
Leakage.
The present invention can emit light wave by several optical wave tubes.The effect of light wave mainly plays heat temperature raising.It is described
Light wave may include infrared ray or far infrared.
As shown in Fig. 2, the microwave cavity 3 of microwave system can surround quartz ampoule 2, such microwave can be through quartz ampoule
Tube wall sufficiently and uniformly irradiation oxidation graphene in a manner of traveling wave；Two optical wave tubes 2 can be distributed in the two sides of quartz ampoule, this
Sample light wave also can pass through quartzy tube wall sufficiently and uniformly irradiation oxidation graphene.Under the synergistic effect of light wave and microwave, oxygen
Graphite alkene can quickly heat up.
In the present embodiment, the reduction of graphene oxide can carry out under vacuum conditions, can be avoided the shadow of air in this way
It rings, because air is easy thermal conductivity to walk.Vacuum degree in container can be in 100Pa or less.The also settable vacuum meter of the present invention,
To facilitate control vacuum degree.
In the present embodiment, the method may further comprise the step of: the obtained graphene oxide is carried out it is cooling, dry
It is dry.Wherein, cooling step may include water cooling, air-flow cooling etc..
In conclusion compared with prior art, advantages of the present invention can include:
(1) present invention can more efficiently remove the foreign ion on graphene oxide, while isolate foreign ion
It will not be combined again with graphene oxide under the action of complexing agent, to improve the completeness of purifying, avoid it and tie repeatedly
It closes, the removal rate of impurity can reach 99% or more on graphene oxide of the present invention.
(2) present invention can during drying the further graphene oxide layer of " strutting " after purification, meanwhile,
Graphene oxide composite material maintains lower entropy under low temperature, is conducive to the microcosmic knot of graphene oxide layer that it " has been strutted "
Structure is kept, so as to obtain the graphene oxide product of higher quality.For example, graphene obtained by method of the invention is not
Only there is complete microstructure, and the number of plies of graphene oxide can be made to be reduced to original 1/3~1/6, for example, the number of plies
5~7 layers can be reduced to from 20~30 layers；The specific surface area of graphene oxide is set to be increased to original 1.5~2.5 times, for example,
Specific surface area is from 100~200m2/ g increases to 200~400m2/g。
(3) heating speed of light microwave reduction is fast, is evenly heated.If heated using external heating method, add to improve
Thermal velocity just needs elevated external temperatures, increases temperature gradient.However it is easy for generating scorched outside and underdone inside phenomenon therewith.And microwave adds
No matter shape when hot, microwave can uniformly penetrating, generate heat, therefore uniformity substantially improves.
(4) different material has different absorptivities to microwave, and the substance containing moisture content is easy to absorb microwave energy.Glass, ceramics,
Polypropylene, polyethylene, fluoroplastics etc. then seldom absorb microwave, and metal all cannot be by microwave heating by reflection wave, these substances.
When microwave heating, being heated material is typically all to be placed on heating interior, and heating room is a closed cavity, electricity for electromagnetic wave
Magnetic wave cannot leak, can only heating object absorb, heating indoor air and cell therefor will not all be heated, so hot
It is high-efficient.Therefore the environment temperature for working at the same time place will not increase, production environment is obviously improved, energy-efficient.
(5) the light microwave pipe-line of corrosion resistance can be used in the equipment during light microwave reduction, not hot with graphene oxide
The corrosive gas decomposited reacts, and is heated evenly in simultaneous reactions pipeline, does not form hot atmosphere air mass, no thermal inertia.
(6) when carrying out light microwave reduction, a large amount of dust will not be generated, operating environment is good.
(7) present invention can according to light microwave power size, processing time come surface of graphene oxide functional group removal rate,
To realize that selective thermal restores, preparation contains the redox graphene material of different oxygen content
(8) microwave energy is transmitted in closing heating room, radio frequency channel pipe, microwave leakage can be made to be strict controlled in national security
In standard index, it is significantly less than the safety standard of country's formulation.And microwave is not belonging to radioactive ray, again without pernicious gas row
It puts, is a kind of foolproof heating technique.
Although those skilled in the art should be clear above by combining exemplary embodiment to describe the present invention
Chu can carry out exemplary embodiment of the present invention each without departing from the spirit and scope defined by the claims
Kind modifications and changes.
Claims (10)
1. a kind of method for producing redox graphene, which is characterized in that the described method comprises the following steps:
It will be combined with foreign ion in functional group and there is the graphene oxide of first number of plies, complexing agent to mix with acid solution,
Form mixed liquor, wherein first number of plies is ten several layers to tens of layers；
Ultrasonic vibration is carried out to the mixed liquor, so that the foreign ion that graphene oxide is combined removes and stablizes with complexing agent
In conjunction with；
Filtering, obtains graphene oxide after purification；
Graphene oxide after purification is dispersed in water, and forms graphene oxide hydrogel；
Graphene oxide hydrogel is placed at the first temperature and the first pressure, so that the hydrone in graphene oxide hydrogel
It congeals into ice and molecule and sublimates, to obtain the graphene oxide with second number of plies, second number of plies is less than described first
The number of plies, first temperature is not higher than -50 DEG C and temperature change is no more than ± 4 DEG C, and first pressure is lower than 1 atmosphere
It presses and pressure change is no more than ± 100Pa；
Graphene oxide with second number of plies is placed in inert atmosphere；
The graphene oxide with second number of plies is brought rapidly up to 500 DEG C or more, to decompose it by microwave and light wave irradiation
Band functional group, institute simultaneously reduces its number of plies, obtains redox graphene, wherein microwave can penetrate the tool in a manner of traveling wave
There is the graphene oxide of second number of plies.
2. the method for production redox graphene according to claim 1, which is characterized in that the complexing agent includes lemon
Lemon acid, sodium citrate, sodium thiosulfate, sodium sulfite, sodium ethylene diamine tetracetate, polyacrylic acid, sodium gluconate or alginic acid
Sodium.
3. the method for production redox graphene according to claim 1, which is characterized in that the filtration step includes
It is filtered by filter membrane, and suction filtration mechanism is set to carry out decompression suction filtration in the lower section of filter membrane.
4. the method for production redox graphene according to claim 1, which is characterized in that first number of plies is 20
~30 layers, second number of plies is 5~7 layers.
5. it is according to claim 1 production redox graphene method, which is characterized in that first temperature-
It is selected within the scope of 55~-65 DEG C and temperature change is no more than ± 2 DEG C.
6. the method for production redox graphene according to claim 1, which is characterized in that first pressure is 10
It is selected in the range of~100Pa and pressure change is no more than ± 10Pa.
7. the method for production redox graphene according to claim 1, which is characterized in that the graphene oxide water
The solid content of gel is 0.1~50wt%.
8. the method for production redox graphene according to claim 1, which is characterized in that described to have the second layer
The step that several graphene oxides is placed in inert atmosphere includes: to be sent into the graphene oxide with second number of plies by gas
In tubular container of the inside full of nitrogen or inert gas, wherein the both ends of the tubular container have opening, the gas energy
Enough to flow into from an opening of tubular container, the gas includes nitrogen or inert gas.
9. the method for production redox graphene according to claim 8, which is characterized in that the microwave and light wave spoke
According to the flow direction in tubular container is mutually perpendicular to the gas in direction.
10. the method for production redox graphene according to claim 8, which is characterized in that in the tubular container
Vacuum degree in 100Pa or less.
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