CN104211050A - Preparation method of suspension liquid and powder of graphene quantum dot - Google Patents

Abstract

The invention discloses a preparation method of graphene quantum dot suspension and powder. The preparation method of the present invention comprises: starting from fullerene, adopting chemical oxidation cutting to prepare graphene quantum dot suspension in one step, removing impurity ions in the suspension, and obtaining graphene quantum dot powder by drying. The invention solves the problems of complex process, high cost and the like in the existing graphene quantum dot suspension and powder preparation methods. The preparation method of the invention is simple to operate, can rapidly scale up and prepare macroscopic graphene quantum dot suspensions and powders, has high yield, has the advantages of uniform size distribution of prepared graphene quantum dots, good water solubility, and the like.

Description

A kind of preparation method of graphene quantum dot suspension and powder

technical field

The invention belongs to the fields of optoelectronic technology and biomarkers, and in particular relates to a method for preparing quantum dots, more particularly to a method for preparing large quantities of graphene quantum dot suspensions and powders. the

Background technique

Graphene has received extensive attention since it was discovered in 2004 due to its excellent electrical, thermal, mechanical, and optical properties. But graphene is a zero-bandgap material, which limits its application in the fields of semiconductor devices and optoelectronic devices. Graphene quantum dots reduce the size to the nanometer scale and use the quantum localization effect to open the band gap, thereby making the transition and recombination of electrons possible, and expanding the application of graphene in the field of optoelectronics and biomarkers. the

The existing methods for preparing graphene quantum dots generally start from precursors such as graphene oxide, graphene, and carbon nanotubes, and cut them into nanometer sizes through the action of strong oxidizing acids. In the preparation process, the large size must be removed by high-speed centrifugation to obtain nano-sized quantum dots. Such a preparation process leads to a very low yield of quantum dots, usually less than 10%, which leads to expensive graphene quantum dots. Moreover, the size distribution of the prepared quantum dots is very inhomogeneous. the

Contents of the invention

The purpose of the present invention is to provide a kind of preparation method of graphene quantum dot suspension and powder for the above-mentioned weak point that prior art exists, and the technical problem to be solved is to promote the productive rate of graphene quantum dot, thereby cut costs. the

Above-mentioned purpose of the present invention can be realized through following technical scheme:

A method for preparing graphene quantum dot suspension and powder, starting from fullerene, cutting graphene quantum dot suspension by chemical oxidation, then removing impurity ions in the suspension, and finally obtaining graphene quantum dot by drying powder. the

A method for preparing a graphene quantum dot suspension and powder as described, wherein the chemical oxidation cutting of fullerene is to mix the precursor fullerene with concentrated sulfuric acid in an ice-water bath and stir at the same time, the fullerene The dosage of concentrated sulfuric acid is 0.5g of fullerene, the ratio of concentrated sulfuric acid is 10-100ml, and the stirring speed is 100-1000rpm; then slowly add sodium nitrate and potassium permanganate, and the dosage of sodium nitrate is 0-3 of the mass of fullerene used. times, the amount of potassium permanganate is 1 to 6 times the mass of the fullerene used; after the addition of potassium permanganate is completed, the ice water bath is 0 to 90 minutes, and then the ice water bath is replaced by a constant temperature water bath, and the temperature is 20 to 40 ° C. Keep warm for 10 minutes to 24 hours; then add pure water, the pure water used is 2 to 5 times the volume of the mixed solution of fullerene, concentrated sulfuric acid, sodium nitrate, and potassium permanganate; ~90min. the

As described a kind of preparation method of graphene quantum dot suspension and powder, wherein said removal of impurity ions in the suspension is to filter the graphene quantum dot suspension made by chemical oxidation cutting to remove large particles, used The pore diameter of the filter membrane is 0.01-0.22um, and then dialyzed in the dialysis bag, changing the water three times a day, the molecular weight cut-off of the dialysis bag used is 500-14000, and the graphene quantum dot suspension is obtained. the

As described a kind of preparation method of graphene quantum dot suspension and powder, wherein said drying is that the suspension obtained after removing the impurity ions in the suspension is dried at normal temperature or in oven, electric furnace, freeze drier Dry to obtain graphene quantum dot powder. the

According to the preparation method of a kind of graphene quantum dot suspension and powder, wherein said precursor fullerene is C20, C36, C44, C50, C60, C70, C76, C80, C84, C90, C94, One or more of C120, C180, and C540, the concentrated sulfuric acid mass fraction is 98%. the

More specifically, the present invention adopts the following technical solutions: 1. Chemical oxidation cutting of fullerenes: the precursor fullerenes and concentrated sulfuric acid are mixed and stirred in an ice-water bath, and the fullerenes used include C20, C36, C44, and C50 . ~1000rpm; then slowly add one or more of sodium nitrate and potassium permanganate, the amount of sodium nitrate is 0 to 3 times the mass of the fullerene used, and the amount of potassium permanganate is the mass of the fullerene used 1 to 6 times; after the addition of potassium permanganate is complete, the ice water bath time is 0 to 90 minutes, and then the ice water bath is replaced with a constant temperature water bath, the temperature is a temperature between 20 and 40 degrees, and the holding time is 10 minutes to 24 hours; then Add pure water, the pure water used is 2 to 5 times the volume of the aforementioned fullerene, concentrated sulfuric acid, sodium nitrate, and potassium permanganate mixture; raise the temperature of the water bath to a temperature between 70 and 100 degrees, and keep the temperature between 0 and 100 degrees. 90min. 2. Removal of impurity ions: filter the suspension obtained in the first step to remove large particles, the pore size of the filter membrane used is 0.01-0.22um; then dialyze in the dialysis bag, change the water three times a day, the molecular weight cut-off 500-14000, the dialysis time is 3-7 days, and the graphene quantum dot suspension is obtained. 3. Drying: drying the suspension obtained in the second step at room temperature or drying in an oven, an electric furnace, or a freeze dryer to obtain graphene quantum dot powder. the

The precursor of the present invention is fullerene, including one or more of C20, C36, C44, C50, C60, C70, C76, C80, C84, C90, C94, C120, C180, C540 and the like. the

The chemical oxidation cutting fullerene of the present invention obtains graphene quantum dot, is to mix one or more of fullerene, concentrated sulfuric acid and potassium nitrate, potassium permanganate successively in ice-water bath, the consumption of concentrated sulfuric acid is The proportion of 0.5g fullerene is 10-100ml concentrated sulfuric acid with mass fraction of 98%. ~1000rpm. the

The chemical oxidation cutting fullerene of the present invention obtains graphene quantum dot, is to mix one or more of fullerene, concentrated sulfuric acid and potassium nitrate, potassium permanganate successively in ice-water bath, the consumption of concentrated sulfuric acid is 0.5 g of fullerene is mixed with 10-100 ml of concentrated sulfuric acid with a mass fraction of 98%. the

The chemical oxidation cutting fullerene of the present invention obtains graphene quantum dot, is that one or more in fullerene, concentrated sulfuric acid and potassium nitrate, potassium permanganate are mixed successively in ice-water bath, and the consumption of sodium nitrate is 0 to 3 times the mass of fullerene used. the

The chemical oxidation cutting of fullerenes of the present invention to obtain graphene quantum dots is to mix one or more of fullerenes, concentrated sulfuric acid, potassium nitrate, and potassium permanganate successively in an ice-water bath, and the dosage of potassium permanganate It is 1 to 6 times the mass of fullerene used. the

The chemical oxidation cutting of fullerenes of the present invention to obtain graphene quantum dots is to mix fullerenes, concentrated sulfuric acid, potassium nitrate, and potassium permanganate one or more successively, and the mixing is carried out in an ice-water bath. After the addition of potassium permanganate is completed, the ice-water bath time is 0-90 minutes. the

The chemical oxidation of the present invention cuts fullerene to obtain graphene quantum dots, and one or more mixed solutions of fullerene, concentrated sulfuric acid, potassium nitrate and potassium permanganate react in a constant temperature water bath, and the constant temperature water bath is divided into two parts. The first stage: first keep the temperature at a certain temperature between 20 and 40 degrees, and the reaction time is 10 minutes to 24 hours; then add the volume of fullerene, concentrated sulfuric acid, potassium nitrate, potassium permanganate mixed solution volume 2 to 5 times Pure water, the temperature of the water bath is raised to a certain temperature between 70 and 100 degrees, and the temperature is kept for 0 to 90 minutes. the

The method for removing impurity ions in the present invention is the method of dialysis, and the molecular weight cut-off of the dialysis bag used is 500-14000. the

The drying method of the present invention is drying at normal temperature or drying in an oven, an electric furnace, or a freeze dryer. the

Description of drawings

Fig. 1 is the suspension that makes graphene quantum dot in the embodiment of the present invention 1;

Fig. 2 is the graphene quantum dot powder that makes in the embodiment of the present invention 2;

Fig. 3 is the atomic force microscope scanning figure of the graphene quantum dot that makes in the embodiment of the present invention 2;

Fig. 4 is the height distribution figure of the graphene quantum dot that makes in the embodiment of the present invention 2;

Fig. 5 is the transmission electron microscope figure of the graphene quantum dot that makes in the embodiment of the present invention 3;

Fig. 6 is a size distribution diagram of graphene quantum dots prepared in Example 3 of the present invention. the

Detailed ways

The substantive content of the present invention will be further described below with reference to the accompanying drawings, but the present invention is not limited thereto. the

Example 1

(1) Weigh 0.5g of C60 powder, measure 10ml of concentrated sulfuric acid with a mass fraction of 98%, mix the C60 powder and concentrated sulfuric acid in a beaker, and place the beaker in an ice-water bath while stirring at a speed of 100rpm. the

(2) Weigh 3g of potassium permanganate powder, and slowly add it to the mixed solution in step 1. the

(3) Remove the ice-water bath and replace it with a water bath, keep the temperature of the water bath at 20 degrees, and react for 24 hours. the

(4) Quickly add 50ml of pure water. the

(5) The suspension obtained in step (4) was filtered, and then dialyzed for 3 days with a dialysis bag with a molecular weight cut off of 8000. the

(6) Dry the suspension obtained in step (5) at room temperature to finally obtain 0.112g graphene quantum dot powder. the

Fig. 1 has shown the suspension of the graphene quantum dot that step (5) obtains. the

Example 2

(1) Weigh 0.5g of C60 powder, measure 25ml of concentrated sulfuric acid with a mass fraction of 98%, mix the C60 powder and concentrated sulfuric acid in a beaker, and place the beaker in an ice-water bath while stirring at a speed of 300rpm. the

(2) Weigh 1.75g of potassium permanganate powder, and slowly add it to the mixed solution in step 1. the

(3) Remove the ice-water bath and replace it with a water bath, keep the temperature of the water bath at 25 degrees, and react for 24 hours. the

(4) Quickly add 75ml of pure water. the

(5) The suspension obtained in step (4) was filtered, and then dialyzed for 7 days with a dialysis bag with a molecular weight cut off of 500. the

(6) The suspension obtained in step (5) was dried in a freeze dryer to finally obtain 0.128g graphene quantum dot powder. the

Fig. 3 has shown the optical picture of the graphene quantum dot that step (6) obtains; Fig. 4 has shown the atomic force microscope scanning figure of graphene quantum dot; Fig. 5 has shown the height distribution of graphene quantum dot, and its height is uniform Distributed in 1 ~ 2nm. the

Example 3

1) Weigh 0.5g of C60 powder, measure 100ml of concentrated sulfuric acid with a mass fraction of 98%, mix the C60 powder and concentrated sulfuric acid in a beaker, and place the beaker in an ice-water bath while stirring at a speed of 300rpm. the

(2) Weigh 0.5g of potassium permanganate powder, and slowly add it to the mixed solution in step 1. the

(3) Remove the ice-water bath and replace it with a water bath, keep the temperature of the water bath at 40 degrees, and react for 1 hour. the

(4) Quickly add 200ml of pure water. the

(5) The suspension obtained in step (4) was filtered, and then dialyzed for 5 days with a dialysis bag with a molecular weight cut off of 1000. the

(6) The suspension obtained in step (5) was dried in a freeze dryer to finally obtain 0.108g graphene quantum dot powder. the

Fig. 6 shows the transmission electron microscope image of the graphene quantum dots obtained in step (6), showing the size distribution of the graphene quantum dots obtained in step (6), and its size is uniformly distributed in 2-3nm. the

Example 4

(1) Weigh 0.5g of C70 powder, measure 25ml of concentrated sulfuric acid with a mass fraction of 98%, mix the C70 powder and concentrated sulfuric acid in a beaker, put the beaker in an ice-water bath, and stir at a speed of 300rpm at the same time. the

(2) Weigh 0.25g of sodium nitrate, slowly add it into the mixed solution in step 1, then weigh 1.75g of potassium permanganate powder, and slowly add it into the mixed solution. the

(3) Remove the ice-water bath and replace it with a water bath, keep the temperature of the water bath at 35 degrees, and react for 10 minutes. the

(4) Quickly add 75ml of pure water, raise the temperature of the water bath to 70 degrees, and keep it warm for 90 minutes. the

(5) The suspension obtained in step (4) was filtered, and then dialyzed for 7 days with a dialysis bag with a molecular weight cut off of 500. the

(6) The suspension obtained in step (5) was dried in an oven to finally obtain 0.115g graphene quantum dot powder. the

Example 5

(1) Take by weighing the mixed powder of 0.5g C20, C36, C44, C50, C60, C70, C76, C80, C84, C90, C94, C120, C180, C540, measure 25ml of concentrated sulfuric acid whose mass fraction is 98%, Mix the C60 powder and concentrated sulfuric acid in a beaker, and place the beaker in an ice-water bath while stirring at a speed of 300 rpm. the

(2) Weigh 1.5g of sodium nitrate, slowly add it to the mixed solution in step 1, and then weigh 1.75g of potassium permanganate powder. the

(3) Remove the ice-water bath and replace it with a water bath, keep the temperature of the water bath at 35 degrees, and react for 60 minutes. the

(4) Quickly add 75ml of pure water, raise the temperature of the water bath to 100 degrees, and keep it warm for 90 minutes. the

(5) The suspension obtained in step (4) was filtered, and then dialyzed for 7 days with a dialysis bag with a molecular weight cut off of 500. the

(6) Dry the suspension obtained in step (5) in an electric furnace to finally obtain 0.105g graphene quantum dot powder. the

In summary, the preparation method of the present invention starts from fullerenes, uses chemical oxidation cutting to prepare a graphene quantum dot suspension in one step, removes impurity ions in the suspension, and obtains graphene quantum dot powder by drying. Compared with the prior art, the preparation method of the graphene quantum dot suspension and powder of the present invention solves the problems of complex process and high cost in the existing graphene quantum dot suspension and powder preparation method. The preparation method of the invention is simple to operate, can rapidly scale up and prepare macroscopic graphene quantum dot suspensions and powders, has high yield, has the advantages of uniform size distribution of prepared graphene quantum dots, good water solubility, and the like. the

Claims (5)

1. a kind of preparation method of graphene quantum dot suspension and powder is characterized in that, starting from fullerene, makes graphene quantum dot suspension with chemical oxidation cutting, then removes impurity ion in suspension, finally by Dry to obtain graphene quantum dot powder. 2. the preparation method of a kind of graphene quantum dot suspension and powder as claimed in claim 1, is characterized in that, described chemical oxidation cutting fullerene is with precursor fullerene and the vitriol oil in ice-water bath Mix and stir at the same time, the amount of fullerene and concentrated sulfuric acid is 0.5g fullerene, the proportion of concentrated sulfuric acid is 10-100ml, the stirring speed is 100-1000rpm; then slowly add sodium nitrate, potassium permanganate, the amount of sodium nitrate is the The mass of fullerene is 0 to 3 times, and the amount of potassium permanganate is 1 to 6 times of the mass of fullerene used; after the addition of potassium permanganate is completed, the ice water bath is 0 to 90 minutes, and then the ice water bath is replaced by a constant temperature water bath , the temperature is 20-40°C, keep warm for 10min-24h; then add pure water, the pure water used is 2-5 times the volume of the aforementioned fullerene, concentrated sulfuric acid, sodium nitrate, potassium permanganate mixed solution; raise the temperature of the water bath To 70 ~ 100 ℃, keep warm for 0 ~ 90min. 3. the preparation method of a kind of graphene quantum dot suspension and powder as claimed in claim 1, is characterized in that, described removal impurity ion in suspension is to be suspended with the graphene quantum dot that chemical oxidation cutting is made Liquid filtration removes large particles, the pore size of the filter membrane used is 0.01-0.22um, and then dialyzed in a dialysis bag, the water is changed three times a day, and the molecular weight cut-off of the dialysis bag used is 500-14000 to obtain a suspension of graphene quantum dots. 4. the preparation method of a kind of graphene quantum dot suspension and powder as claimed in claim 1, is characterized in that, described drying is the suspension normal temperature drying that obtains after the impurity ion in the suspension will be removed or in oven , an electric furnace, and a freeze dryer to obtain graphene quantum dot powder. 5. the preparation method of a kind of graphene quantum dot suspension and powder according to claim 2, is characterized in that, described precursor fullerene is C20, C36, C44, C50, C60, C70, C76, C80 , C84, C90, C94, C120, C180, C540 in one or more, the mass fraction of the concentrated sulfuric acid is 98%.