CN105565297B - Graphene quantum dot and method prepared by electrochemical oxidation cutting carbon fiber tip surface - Google Patents
Graphene quantum dot and method prepared by electrochemical oxidation cutting carbon fiber tip surface Download PDFInfo
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Abstract
The graphene quantum dot and method prepared the invention provides a kind of electrochemical oxidation cutting carbon fiber tip surface.This method comprises the following steps：Dc source both positive and negative polarity is connected respectively as negative electrode using carbon fiber as anode, inert electrode；Inert electrode is dipped in electrolyte solution entirely；Carbon fiber tip surface is contacted with electrolyte solution liquid level before being powered；Carbon fiber tip surface operation interval is located in the range of the 3 to 5mm of electrolyte solution liquid level during energization；By being interrupted or continuously controlling carbon fiber tip surface to be in the operation interval, the micro crystal graphite lamella on carbon fiber tip surface is set to be electrochemically oxidized expansion dissociation and cut into graphene quantum dot.The graphene quantum dot that the present invention is provided is prepared by this method, and its number of plies is 1 10 layers, particle diameter is 1 100nm.The preparation method of the present invention has higher oxidation expansion dissociation and cutting power, realizes that the number of plies is lower, the uniform smaller graphene quantum dot of particle diameter distribution preparation.
Description
Technical field
The invention belongs to technical field of nanometer material preparation, specially a kind of electrochemical oxidation cutting carbon fiber tip surface system
The method of standby graphene quantum dot, and then obtain a series of there is different nano-scales, different carbon/oxygen than the stone with different qualities
Black alkene quantum dot.
Background technology
Graphene be one kind by carbon atom with sp2Two dimension (2D) hexangle type of hybridized orbit composition is in the plane of honeycomb lattice
Individual layer, and be the basic building module of all other dimension graphite material.It can be packaged into zero dimension (0D) fullerene,
It is rolled into the nanotube of one-dimensional (1D) or is stacked into the graphite of three-dimensional (3D).Graphene be at present it is most thin in the world be but also most hard
Nano material, it is almost fully transparent, only absorb 2.3% light；Thermal conductivity factor is up to 5300W/mK, is received higher than carbon
Its electron mobility is more than 15000cm under mitron and diamond, normal temperature2/ Vs, far above CNT or silicon crystal, and
Its resistivity only has 10-6Ω cm, it is lower than copper or silver, it is the minimum material of current resistivity in the world.Because its electricity
Resistance rate is extremely low, and electric transmission speed is exceedingly fast, therefore is expected to for developing conduction rate electronic component or crystalline substance of new generation faster
Body pipe.Graphene is substantially also a kind of transparent, good conductor, is especially suitable for for manufacturing transparent touch-sensitive panel, tabula rasa, even
It is solar cell.Graphene also has an important characteristic, and quantum hall effect can be observed at normal temperatures, therefore at it
Development to future electronic device is played special effect by the further investigation in field, and available for the high speed electricity for preparing low energy consumption
Sub- device.
Graphene quantum dot (Graphene quantum dot, GQD) is the nano material of quasi-zero dimension, and its internal electron exists
Motion in all directions is all limited to, so quantum local effect is particularly significant, with many unique properties.Itself and tradition
Semiconductor-quantum-point compare, new graphene quantum dot has following unique property：1) without highly toxic metal member
Plain such as cadmium, lead, belong to environment-friendly type quanta point material；2) structure is highly stable, resistance to strong acid, highly basic, resistance to photoetch (conventional semiconductors
Applied to photoelectrochemicalcell cell photooxidation easily occurs for quantum dot, causes hydraulic performance decline and low device lifetime)；3) thickness thin can be arrived
Monoatomic layer, and widthwise size can be reduced to the size of a phenyl ring, but remain in that the chemical stability of height；4) band gap is wide
Spend scope adjustable, can be adjusted in principle by quantum local effect and boundary effect in the range of 0-5eV, so that by wave-length coverage
Visible ray and dark purple outskirt are expanded to from infrared region, particular/special requirement of the various technologies to material energy gap and characteristic wavelength is met；5)
Easily realize surface-functionalized, be stably dispersed in common solvents, meet the demand of material low cost working process.This will be
Revolutionary change is brought in electronics, photoelectricity and electromagnetism field.It can be applied to solar cell, electronic equipment, light
In terms of dyestuff, biomarker and multiple microparticles system.Graphene quantum dot is in biology, medical science, material, novel semi-conductor device
The fields such as part have important potential application.It can realize monomolecular sensor, it is also possible to expedite the emergence of extra small transistor npn npn or utilization
The chip communication that semiconductor laser is carried out, for make chemical sensor, solar cell, medical imaging apparatus or
Nanoscale circuit etc..
For from size, graphene quantum dot and graphene something in common be on thickness be individual layer or few layer (no
More than 10 layers, every layer of thickness is in 0.34-0.40nm or so), difference is of different sizes on planar orientation, and the former is less than
100nm, the latter is then more than micron order yardstick.The former preparation difficult point is how to obtain smaller nanoscale quantum dot, and
The preparation difficult point of the latter is number of plies control.This causes the two to there is very big difference in the selection of raw material and preparation method.
For example for top-down preparation method, from raw material for, the former using crystallite carbon material advantageously, such as carbon fiber
Crystallite yardstick only have tens nanometer (《Carbon fiber and graphite fibre》, He Fu writes, Beijing：Chemical Industry Press, 2010),
How as far as possible will be every as long as the difficult point that therefore dissociating method is properly readily available in graphene quantum dot, preparation method is
One crystallite is all independently cut out from body phase, and as obtaining, individual layer yardstick is then relative to be easy to (be based on microwafer footpath and thickness
Degree only has few tens of nanometers, and interlayer Van der Waals force is smaller)；And the latter has big lamella crystal structural carbon using high-graphitized
Material advantageously, such as crystalline flake graphite, the difficult point in preparation method be how as far as possible by each lamella from crystalline phase
It is middle independently to cut out (the interlayer Van der Waals force based on large scale graphite crystal is larger), as the large scale for obtaining planar orientation
It is then relatively easy, thus at present the existing product for use top-down preparation method to frequently result in be with large scale lack layer or
Based on multi-layer graphene (preparation method in such as US7658901, CN103935999A, CN101634032A), and use under
And on preparation method obtain the single-layer graphene of large scale more relatively easily, for example CVD chemical gaseous phase depositing process is (such as
Preparation method in US2009110627A1), but prepared by batch is a difficult point.
Below mainly from the angle of materialogy, the thinking continued to use from top to bottom and from bottom to top introduces existing
Graphene quantum dot preparation method.Top-to-bottom method refers to by either physically or chemically by large-sized graphene platelet
Cut into the graphene quantum dot of small size.For example：CN102660270A《Solvent-thermal method prepares the side of fluorescence graphene quantum dot
Method》Graphene oxide is prepared first, and graphene oxide is then cut into quantum dot, CN102616774A using solvent heat《One
Plant the method for preparing graphene quantum dot》It is to add amine passivator in hydro-thermal cutting process, their shortcoming is hyperpyrexia, height
Can, it yield poorly；CN102336404A《The preparation method of graphene oxide quantum dot based on photochemical catalytic oxidation》, ultrasonic, double
Graphene oxide quantum dot is prepared with reference to ultraviolet radioactive under oxygen water and catalyst action, quantum dot prepared by this method is distributed
To raising, but the preparation of high yield is difficult to, and quantum dot shape is difficult to control to edge pattern；2012
Chem.Eur.J. Electrochemical preparation of luminescent graphene quantum dots
From multiwalled carbon nanotubes and J.Mater.Chem. Facile synthesis of water-
soluble,highly fluorescent graphene quantum dots as a robust biological label
For stem cells, water-soluble preferably graphene quantum dot, but the early stage of raw material graphite is prepared using electrochemical stripping
Handling work, time-consuming, and later-period purification step is time-consuming also longer, and product yield is not high；CN102208755A《Ultraviolet light etching is dry
The method that method prepares graphene quantum dot》The graphene on mica sheet, which is etched, using ultraviolet light obtains graphene quantum dot, this side
The shortcoming of method is that have radiation, the big, preparation amount that consumes energy small；The Graphene quantum dots that Nano Letter in 2012 are delivered
At room temperature carved out from few-layer graphene, have been obtained using electron beam lithography
Graphene prepares graphene quantum dot.These methods are all through oxidization-reduction, then cut, and are carried out in several steps, and preparation process is numerous and diverse,
Cycle is long, yields poorly, and condition is harsh, it is difficult to promote.CN103265020A《A kind of macroscopic preparation of graphene quantum dot powder
Method》From natural flake graphite, natural flake graphite is changed into graphite nanoparticles by the first step, and second step is by graphite
Nano particle is changed into single order intercalation nano graphite oxide, and single order intercalation nano graphite oxide is placed in non-tight by the 3rd step lid
In crucible, heat treatment, which is obtained in graphene quantum dot powder, second step, in atmosphere will use substantial amounts of strong acid and strong oxidizer,
Whole preparation process is complicated, and time-consuming, seriously polluted, and particle diameter and number of plies distributed controll are poor, and the heat treatment of the 3rd step can cause
Product hydrophilicity is deteriorated.In addition, the preparation method using crystallite carbon material as carbon source is also used：Nano Letter in 2012
The Graphene quantum dots derived from carbon fibers delivered, use carbon fiber for carbon source, pass through
The graphite of stacking in fiber is peeled off in acid treatment, and the graphene quantum dot of a large amount of different-grain diameter distributions can be just made in an only step, should
Method advantage is that step is simple and raw material is cheap, but has the disadvantage that preparation process will use substantial amounts of sulfuric acid and nitric acid, and time-consuming, dirty
Dye is serious, and particle size distribution range is very wide, it is necessary to follow-up dialysis separating treatment obtains smaller granularity, causes effectively to make
Standby low yield；The One-step and high yield simultaneous that J.Mater.Chem. in 2012 is delivered
preparation of single-and multi-layer graphene quantum dots from CX-72carbon
Black, using 30nm carbon black pellets as raw material, in HNO3Middle long-time high temperature reflux, is then centrifuged for obtaining two kinds of sizes
Graphene quantum dot, but carbon black feed stock is complicated, non-sp2Structure is more, hence in so that the quantum point defect arrived is more, product quality
Difference.
Bottom-to-top method then refers to that make predecessor with small molecule prepares graphene quantum by series of chemical
Point.CN103320125A《The preparation method of multicolor fluorescence graphene quantum dot material》Selection pyrene is predecessor, at low temperature will
The surface of pyrene crystal grain carries out oxygen functionalization, then carried out in the presence of catalyst hydrazine hydrate and ammoniacal liquor low temperature hydro-thermal dehydrogenation,
Growth is surface-functionalized with original position.Generally speaking, the most controllabilitys of bottom-to-top method are stronger, but complex steps operation fiber crops
Tired, yield is relatively low, and the synthetic method still without suitable industrial volume production occurs at present.
In summary, exploitation one kind takes into account that particle diameter is small, the number of plies is low and it is controllable to be distributed, and raw material sources are abundant and inexpensive, production
Equipment is simple, preparation process is simple, the low, production efficiency that consumes energy is high, yield is high and it is free of contamination can industrial volume production it is high-quality
The preparation method of graphene quantum dot, is still the key issue for being badly in need of in technical field of nanometer material preparation solving.
The content of the invention
In order to solve the above technical problems, cutting carbon fiber tip surface it is an object of the invention to provide a kind of electrochemical oxidation
The graphene quantum dot and its method of preparation.The graphene quantum dot preparation method of the present invention is compared to Conventional electrochemical preparation side
Method has higher oxidation expansion dissociation and cutting power, can realize that the number of plies is lower, particle diameter distribution is uniform smaller
The preparation of graphene quantum dot.
To reach above-mentioned purpose, the present invention provides a kind of electrochemical oxidation cutting carbon fiber tip surface and prepares graphene quantum
The method of point, it comprises the following steps：
Using a flocked carbon fibers (monofilament or multifibres) as anode, using an inert electrode as negative electrode, respectively with direct current
Positive pole, the negative pole of power supply are connected；
The inert electrode is dipped in an electrolyte solution entirely；
The working face of carbon fibre anode is made up of neat tow tip surface, before energization by carbon fiber tip surface with it is described
Electrolyte solution liquid level is parallel to be in contact；
Then it is initially powered up, the operation interval of carbon fiber tip surface is located at below electrolyte solution liquid level to upper during energization
In the range of-the 3mm to 5mm of side；
By being interrupted or continuously controlling carbon fiber tip surface to be in the operation interval so that on carbon fiber tip surface
Micro crystal graphite lamella be electrochemically oxidized expansion dissociation and cut into graphene quantum dot, and be dissolved in the electrolyte solution
In, obtain graphene quantum dot solution.
In the methods described above, it is preferable that selected raw material carbon fiber is made up of micro crystal graphite lamellar structure, crystallite
Three-dimensional dimension is not less than 60% in 10-100nm, micro crystal graphite lamellar orientation compared to fiber axis orientation, is by high temperature cabonization
Obtained variously-shaped conductive carbon material, the filament diameter of tow is 1-15 μm.Micro crystal graphite lamella size is small, after being conducive to
Continuous electrochemical oxidation dissection, makes it be dissociated into 1-10 layers, particle diameter 1-100nm graphene quantum dot；And it is highly oriented favourable
Controlled in Electrochemical Cutting process for the size and dimension of graphene quantum dot；The electric conduction of carbon fiber obtained by high temperature cabonization
Property it is good, be conducive to the electric transmission needed for electrochemical oxidation and cutting process, be also beneficial to reduce preparation process in heating show
As；Tow shape form is conducive to CURRENT DISTRIBUTION evenly, is also beneficial to electric current and directly acts on each microstructure completion quickly
Oxidation and cutting process, and regular form can prevent the uncontrolled fracture of wire of fiber, be to have for the effective yield for improving product
Profit.
In above-mentioned preparation process, using a flocked carbon fibers as anode, an inert electrode is regard as negative electrode, difference
Positive pole, negative pole with dc source are connected, and wherein inert electrode is dipped in the electrolyte solution of electrolytic cell entirely, and carbon fiber is positive
Pole working face constitutes for neat tow tip surface, should be by carbon fiber tip surface phase parallel with electrolyte solution liquid level before energization
Contact (allows tip surface to enter the error of solution and is no more than 3mm for relative liquid surface), in surface tension and anodic oxidation after energization
Occur in that liquid level climbs under the mechanism for generating bubble, the electrolyte for causing carbon fiber tip surface to be operated in before being powered
During the top of liquid level of solution, energization the operation interval of carbon fiber tip surface be located at electrolyte solution liquid level below to top-
In the range of 3mm to 5mm (negative value is represented below liquid level, on the occasion of expression in ullage)；By being interrupted or continuously controlling carbon
It is interval that fibre tip face is in above-mentioned energization liquid level mobile working so that the micro crystal graphite lamella on carbon fiber tip surface is electric
Chemical oxidation expansion is dissociated and cuts into 1-10 layers, particle diameter 1-100nm graphene quantum dot, and is dissolved in electrolyte solution
In；Also further graphene quantum dot can be separated with solution, obtains colloidal attitude or the graphene quantum dot of solid-state.This
Preparation method is different from traditional electrochemistry preparation process, and it can act on current convergence in the region of one very little, not only real
Showed being uniformly distributed for current density, it is to avoid working electrode different parts in Conventional electrochemical preparation method (end face, side,
In solution, at liquid level) fracture of wire, product form and size difference problem caused by electric current distribution is uneven, and
High energy density is obtained, compared to Conventional electrochemical preparation method there is higher oxidation expansion to dissociate and cutting energy
Power, it is achieved thereby that the number of plies is lower, grain size is smaller, be more evenly distributed, size is controllable, high-yield quick graphene quantum dot
Preparation.
In the methods described above, it is preferable that the carbon fiber can be polyacrylonitrile-based carbon fibre, asphalt base carbon fiber,
One kind in viscose-based carbon fiber and graphite fibre.
In the methods described above, it is preferable that the inert electrode is the conductive electrode with potential resistance to electrolyte contamination solution corrosion；More
Preferably, the inert electrode can be conventional stainless steel, titanium, platinum, nickel-base alloy, copper, lead, graphite and titanium-based oxide electricity
One kind in extremely.
In the methods described above, it is preferable that the electrolyte solution is the solution with ion conductivity, and the electricity
The electrical conductivity of electrolyte solution is not less than 10mS/cm.Too low electrical conductivity of solution can make the reduction of electrical-chemistry method efficiency, solution temperature rise
Too fast, energy consumption increase, product quality declines.
In the methods described above, it is preferable that described electrochemical oxidation cutting process electrochemical control parameter is direct current
The operating voltage in source is not higher than 80V, is 1-30A/cm relative to the working current density on carbon fiber tip surface2, meeting work
It can be constant pressure or constant current output control mode to make the lower dc source of current density requirement.Direct-current working volts are defeated in order to meet
Go out enough operating current requirements.Working current density on carbon fiber tip surface is low to cause oxidation cutting power to decline, no
Only efficiency is low, can also influence the quality of product；Although working current density height can improve oxidation cutting power, too high to cause
The ablation of carbon fiber, solution temperature rise is serious or even largely decomposes, and yield declines, energy consumption increase, and then influences the quality of product.
According to the embodiment of the present invention, it is preferable that the above method is further comprising the steps of：By the graphene amount
Son point solution is by vacuum filter and/or dialysis treatment with the particle diameter distribution of further narrowed graphene quantum dot.
According to the embodiment of the present invention, it is preferable that the above method is further comprising the steps of：By the graphene amount
Graphene quantum dot in son point solution is separated with liquid, obtains colloidal attitude or the graphene quantum dot of solid-state.More preferably
Ground, the method that the graphene quantum dot in the graphene quantum dot solution is separated with liquid includes centrifugation, vacuum and done
One or more of combinations in dry and freeze-drying.
In the methods described above, it is preferable that the preparation production of described 1-10 layers, particle diameter 1-100nm graphene quantum dot
Rate is not less than 90%.
In the methods described above, it is preferable that the carbon of the graphene quantum dot prepared/oxygen atom ratio is 2:1-20:1.
According to the embodiment of the present invention, it is preferable that the above method is further comprising the steps of：By described graphene
Quantum dot (solution or colloidal attitude or solid-state) is gone back by liquid phase chemical reduction and electrochemical reduction, thermal reduction, ultraviolet irradiation
One or more in original, microwave reduction, active metal reduction and vapour phase reduction handle further to improve carbon/oxygen atom ratio.
In the methods described above, it is preferable that when using polyacrylonitrile-based carbon fibre for raw material, obtained graphene quantum
Point contains N doping, and nitrogen-atoms is 1-6% than content (atom number content).
The graphene quantum dot preparation method of the present invention has higher oxidation swollen compared to Conventional electrochemical preparation method
Swollen dissociation and cutting power, it is achieved thereby that the number of plies is lower, grain size is smaller, be more evenly distributed, size is controllable, high-yield quick
Graphene quantum dot preparation.
The present invention also provides a kind of graphene quantum dot, and it is to cut carbon fiber tip surface system by above-mentioned electrochemical oxidation
The method of standby graphene quantum dot is preparation-obtained.
According to the embodiment of the present invention, it is preferable that the graphene quantum dot is 1-10 layers, particle diameter 1-100nm
Graphene quantum dot.
According to the embodiment of the present invention, it is preferable that the carbon of the graphene quantum dot/oxygen atom ratio is 2:1-
20:1。
According to the embodiment of the present invention, it is preferable that the graphene quantum dot contains N doping, and nitrogen-atoms ratio contains
Measure as 1-6%.
The graphene quantum dot preparation method of the present invention has higher oxidation swollen compared to Conventional electrochemical preparation method
Swollen dissociation and cutting power are a kind of while having that particle diameter is small, the number of plies is low and it is controllable to be distributed, and raw material sources are abundant and inexpensive, give birth to
Produce equipment simple, preparation process is simple, the low, production efficiency that consumes energy is high, yield is high and it is free of contamination can industrial volume production the advantages of
High-quality graphene quantum dot preparation method.
Brief description of the drawings
Fig. 1 prepares the Method And Principle of graphene quantum dot for the electrochemical oxidation cutting carbon fiber tip surface that the present invention is provided
Schematic diagram；
The microstructure schematic diagram on carbon fibre tow and its monofilament that Fig. 2 uses for the present invention；
Fig. 3 a are the atomic force microscope images for the graphene quantum dot that embodiment 1 is provided；
Fig. 3 b are the Elevation Analysis curve for the graphene quantum dot that embodiment 1 is provided；
Fig. 4 is the grading curve for the graphene quantum dot that embodiment 1 is provided；
Fig. 5 is the uv absorption spectra for the graphene quantum dot that embodiment 1 is provided；
Fig. 6 is the fluorescence spectra for the graphene quantum dot that embodiment 1 is provided.
Primary clustering symbol description：
The bubble 7 of 5 tow tip surface of anode 1 negative electrode, 2 dc source, 3 electrolytic cell, 4 electrolyte solution 6 climbs liquid level 8
Graphene quantum dot 9
Embodiment
In order to which technical characteristic, purpose and beneficial effect to the present invention are more clearly understood from, now to the skill of the present invention
Art scheme carry out it is described further below, but it is not intended that to the present invention can practical range restriction.
The electrochemical oxidation cutting carbon fiber tip surface that the present invention is provided prepares the Method And Principle signal of graphene quantum dot
Figure is as shown in figure 1, using a tow carbon fiber as anode 1, using an inert electrode as negative electrode 2, respectively with dc source 3 just
Pole, negative pole are connected, and wherein inert electrode is dipped in the electrolyte solution 5 of electrolytic cell 4 entirely, and carbon fibre anode working face is whole
Neat tow tip surface 6 is constituted, and should be in contact before energization by carbon fiber tip surface is parallel with electrolyte solution liquid level, after energization
The liquid level 8 that climbs is occurred in that under surface tension and the mechanism of anode generation bubble 7, carbon fiber tip surface can also be operated in
The operation interval of carbon fiber tip surface is located at below electrolyte solution liquid level to upper during the top of electrolyte solution liquid level, energization
In the range of-the 3mm to 5mm of side；By interruption or continuously control carbon fiber tip surface to be in above-mentioned energization liquid level and move work
Make interval so that the micro crystal graphite lamella on carbon fiber tip surface is electrochemically oxidized expansion dissociation and cuts into 1-10 layers, grain
Footpath 1-100nm graphene quantum dot 9, and be dissolved in electrolyte solution, so as to obtain graphene quantum dot solution.Wherein institute
The microstructure schematic diagram on carbon fibre tow and its monofilament stated is as shown in Fig. 2 the raw material carbon fiber selected is by microlite
Ink sheet Rotating fields are constituted, and crystallite three-dimensional dimension is not less than in 10-100nm, micro crystal graphite lamellar orientation compared to fiber axis orientation
60%, it is the variously-shaped conductive carbon material obtained by high temperature cabonization, preferably tow shape form, filament diameter is 1-15 μ
m。
Technical scheme is further described below by embodiment.
Embodiment 1
Using T30012K (12000 monofilament) polyacrylonitrile-based carbon fibre tow as raw material, the filament diameter of the carbon fiber is
7 μm, it is made up of micro crystal graphite lamellar structure, and crystallite three-dimensional dimension is in 10-40nm, and micro crystal graphite lamellar orientation is compared to fiber
Axle is oriented to 80%.The tip surface of above-mentioned 78 beam carbon fibre tow is had one's hair trimmed, and is vertically arranged in and fills concentration for 0.5M hydroxides
Above the electrolytic cell of sodium water solution, it is connected as anode with the positive pole of dc source；It is again 100cm by an area2SS
304 stainless (steel) wires are dipped in solution entirely, are connected as negative electrode with the negative pole of dc source；Carbon fiber is carefully adjusted before energization
The parallel distance of the neat tip surface of tow and liquid level of solution, is defined, it is allowed to which tip surface enters solution by just touching liquid level
Error for relative liquid surface be no more than 3mm；Dc source is then turned on, constant voltage 32V is controlled, started working, anode has greatly
Bubble formation is measured, visible solution climbs in the presence of surface tension and anodic oxidation generation bubble, now also can adjust carbon fine
Dimension tip surface works in the range of ullage is no more than 5mm, now the working current density fluctuation of opposite tip face area
Scope is 1-10A/cm2；Enter trade current density less than 1A/cm with electrolytic process2When (phenomenon be tip surface with liquid level away from
From widening), can adjust the tip surface that furthers is carried out continuously electrolytic process with liquid level distance, can also first tune up tip surface and liquid
Identity distance from making after reaction interrupts, then further again tip surface and liquid level distance in -3mm to 5mm operated within range, so as to realize electricity
The intermitten service of solution preocess；Along with the progress of electrolytic process, the micro crystal graphite lamella on carbon fibre tow tip surface is electrochemical
Learn oxidation expansion dissociation and cut, constantly dissolving enter in solution, solution colour change over time gradually by it is yellowish, bright orange,
Dark yellow, yellowish-brown to arrive dark brown, the graphene quantum dot concentration of correspondence generation gradually increases, and finally obtains concentration not higher than 10mg/
ML graphene quantum dot solution.
Graphene quantum dot solution obtained above is transferred on smooth silicon chip, atomic force microscopy is carried out after natural drying
Sem observation, such as Fig. 3 a and Fig. 3 b, quantum dot maximum height are 0.706nm, equivalent to the thickness of two layer graphenes, its particle diameter distribution
Average height is 0.339nm, equivalent to the height of single-layer graphene, and is distributed than more uniform.By graphene amount obtained above
Son point solution directly carries out the analysis of dynamic light scattering (DLS) particle diameter distribution, and such as Fig. 4 obtains its particle size distribution range for 10-
20nm, distributed area is narrower；Further carry out ultraviolet absorption spectroscopy, such as Fig. 5, it is seen that it is special that it has significant light absorbs
Property；And then by spectrofluorimetry, such as Fig. 6, in the case where excitation wavelength is 480nm, its launch wavelength is 540nm；Obtained above-mentioned
The graphene quantum dot solution arrived passes through 2000D film dialysis treatments, obtains particle diameter distribution 5-10nm graphene quantum dot solution.
By particle diameter distribution 5-10nm obtained above graphene quantum dot solution by obtaining gluey graphene amount after vacuum drying
Sub-, by it, further 500 DEG C of thermal reductions obtain the graphene quantum dot powder of solid-state, photoelectron spectroscopy under nitrogen protection
(XPS) analysis obtains its carbon/oxygen and compares 11:1；XPS shows that it also contains nitrogen, and nitrogen-atoms is 2.6% than content, and this is due to
Polyacrylonitrile-based carbon fibre raw material inherently contains nitrogen, therefore the graphene quantum dot obtained here is containing N doping
's.By relatively more obtained graphene quantum dot quality and the weightless quality of carbon fibre tow, the system of graphene quantum dot is obtained
Standby yield is 93%.
Embodiment 2
It is with the Main Differences of embodiment 1：Using T70012K polyacrylonitrile-based carbon fibres tow as raw material, the carbon fiber
Filament diameter be 7 μm, it is made up of micro crystal graphite lamellar structure, and crystallite three-dimensional dimension takes in 15-50nm, micro crystal graphite lamella
90% is oriented to compared to fiber axis；The electrolyte solution used is 0.5M ammonium carbonate；Negative electrode is 100cm2Nickel sheet；Control
Constant voltage 40V, working current density fluctuation range is 1-20A/cm2.Obtained graphene quantum dot is 1-2 layers, particle diameter point
Cloth scope is 7-15nm.By graphene quantum dot solution obtained above by obtaining spongiform solid graphite after freeze-drying
Alkene quantum dot.Hydrazine hydrate reduction is added in graphene quantum dot solution obtained above and obtains reduction state graphene quantum dot,
Its carbon/oxygen is than 3 before not reducing:1 brings up to 20:1.The yield for preparing of graphene quantum dot is 95%.
Embodiment 3
It is with the Main Differences of embodiment 2：Using current constant control mode, working current density is 15A/cm2, voltage wave
Dynamic scope is 30-50V.Obtained graphene quantum dot is 1-2 layers, and particle size distribution range is 5-10nm, carbon/oxygen without reduction
Than 9:1, it is 98% to prepare yield.
Embodiment 4
It is with the Main Differences of embodiment 1：Using 100 beam M55J 3K celions tow as raw material, the carbon fiber
Filament diameter is 5 μm, and it is made up of micro crystal graphite lamellar structure, and crystallite three-dimensional dimension is in 30-80nm, micro crystal graphite lamellar orientation
99% is oriented to compared to fiber axis；The electrolyte solution used is 0.2M sulfuric acid；Negative electrode is 200cm2TA2 titanium nets；Using
Current constant control mode, working current density is 25A/cm2, scope range of the fluctuation of voltage is 50-80V.Obtained graphene quantum dot is
1-2 layers, particle size distribution range is 15-25nm, and carbon/oxygen without reduction compares 15:1, it is 96% to prepare yield.
Embodiment 5
It is with the Main Differences of embodiment 1：Using 220 beam HM1104K asphalt base carbon fibers tow as raw material, the carbon fiber
Filament diameter be 10 μm, it is made up of micro crystal graphite lamellar structure, and crystallite three-dimensional dimension is in 50-100nm, micro crystal graphite lamella
Orientation is oriented to 98% compared to fiber axis；The electrolyte solution used is 1.0M sodium sulphate；Negative electrode is 50cm2Netted titanium-based
Yttrium oxide coated electrode；Using current constant control mode, working current density is 10A/cm2, scope range of the fluctuation of voltage is 20-50V.
The graphene quantum dot arrived is 1-2 layers, and particle size distribution range is 3-7nm, and carbon/oxygen without reduction compares 5:1, preparing yield is
93%.
Embodiment 6
It is with the Main Differences of embodiment 5：The electrolyte solution used for 1.0M sodium sulphate and 0.1M sulfuric acid mixing
Liquid；Using current constant control mode, working current density is 3A/cm2, scope range of the fluctuation of voltage is 10-20V.Obtained graphene amount
Son point is layer 2-4, and particle size distribution range is 30-50nm, and carbon/oxygen without reduction compares 2:1, it is 90% to prepare yield.
Finally, the graphene quantum dot obtained by the embodiment of the present invention 5, embodiment 3 and embodiment 1 leads in aqueous
Burst of ultraviolel optical wavelength 365nm irradiations are crossed, blueness, green and yellow fluorescence can be shown respectively, and (this may be with graphene amount
The particle diameter distribution of son point is relevant).
Claims (11)
1. a kind of method that electrochemical oxidation cutting carbon fiber tip surface prepares graphene quantum dot, it comprises the following steps：
Using a flocked carbon fibers as anode, an inert electrode is regard as negative electrode, positive pole respectively with dc source, negative pole phase
Connection；
The inert electrode is dipped in an electrolyte solution entirely；
The working face of carbon fibre anode is made up of neat tow tip surface, by carbon fiber tip surface and the electrolysis before energization
Matter liquid level of solution is parallel to be in contact；
Then it is initially powered up, the operation interval of carbon fiber tip surface, which is located at below electrolyte solution liquid level, during energization arrives top
- 3mm to 5mm in the range of；
By being interrupted or continuously controlling carbon fiber tip surface to be in the operation interval so that micro- on carbon fiber tip surface
Brilliant graphite flake layer is electrochemically oxidized expansion dissociation and cuts into graphene quantum dot, and is dissolved in the electrolyte solution,
Obtain graphene quantum dot solution.
2. according to the method described in claim 1, its is further comprising the steps of：The graphene quantum dot solution is passed through into vacuum
Filtering and/or dialysis treatment are with the particle diameter distribution of further narrowed graphene quantum dot.
3. method according to claim 1 or 2, its is further comprising the steps of：By in the graphene quantum dot solution
Graphene quantum dot is separated with liquid, obtains colloidal attitude or the graphene quantum dot of solid-state.
4. method according to claim 3, wherein, by the graphene quantum dot and liquid in the graphene quantum dot solution
The method that body is separated includes one or more of combinations in centrifugation, vacuum drying and freeze-drying.
5. the method according to any one of claim 1,2 or 4, its is further comprising the steps of：By described graphene amount
Son point irradiates reduction, microwave reduction, active metal reduction by liquid phase chemical reduction and electrochemical reduction, thermal reduction, ultraviolet
Handled with the one or more in vapour phase reduction further to improve carbon/oxygen atom ratio.
6. method according to claim 3, its is further comprising the steps of：Described graphene quantum dot is passed through into liquid phase
Learn in reduction and electrochemical reduction, thermal reduction, ultraviolet irradiation reduction, microwave reduction, active metal reduction and vapour phase reduction
One or more handle further to improve carbon/oxygen atom ratio.
7. according to the method described in claim 1, wherein, the carbon fiber is made up of micro crystal graphite lamella, the microlite
Ink sheet layer three-dimensional dimension be 10-100nm, the micro crystal graphite lamellar orientation compared to carbon fiber axle to the degree of orientation be not less than
60%, and the carbon fiber is the conductive carbon fibre obtained by high temperature cabonization, is polyacrylonitrile-based carbon fibre, pitch base carbon
One kind in fiber, viscose-based carbon fiber and graphite fibre, the filament diameter of tow is 1-15 μm.
8. according to the method described in claim 1, wherein, the inert electrode for potential resistance to electrolyte contamination solution corrosion conduction electricity
Pole.
9. method according to claim 8, wherein, the inert electrode be stainless steel, titanium, platinum, nickel-base alloy, copper, lead,
One kind in graphite and titanium supported oxide electrode.
10. according to the method described in claim 1, wherein, the electrolyte solution be the solution with ion conductivity, and
And the electrical conductivity of the electrolyte solution is not less than 10mS/cm.
11. according to the method described in claim 1, wherein, the operating voltage of the dc source is not higher than 80V, relative to carbon
Working current density on fibre tip face is 1-30A/cm2, the dc source is constant pressure or constant current output control mode.
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| CN201410538019.1A CN105565297B (en) | 2014-10-13 | 2014-10-13 | Graphene quantum dot and method prepared by electrochemical oxidation cutting carbon fiber tip surface |
| KR1020177009296A KR20170070031A (en) | 2014-10-13 | 2015-09-14 | Graphene oxide prepared by electrochemically oxidizing and cutting end face of carbon-based three-dimensional material and method therefor |
| US15/518,227 US10787746B2 (en) | 2014-10-13 | 2015-09-14 | Graphene oxide prepared by electrochemically oxidizing and cutting end face of carbon-based three-dimensional material and method therefor |
| JP2017538283A JP6963501B2 (en) | 2014-10-13 | 2015-09-14 | Graphene oxide produced by electrochemically oxidatively cutting the end face of a carbon-based three-dimensional material and its production method. |
| PCT/CN2015/089495 WO2016058466A1 (en) | 2014-10-13 | 2015-09-14 | Graphene oxide prepared by electrochemically oxidizing and cutting end face of carbon-based three-dimensional material and method therefor |
| EP15850068.6A EP3208235A4 (en) | 2014-10-13 | 2015-09-14 | Graphene oxide prepared by electrochemically oxidizing and cutting end face of carbon-based three-dimensional material and method therefor |
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