a supercritical co 2 Method for preparing graphene with assisted liquid phase exfoliation

Abstract

The invention relates to a method utilizing supercritical CO 2 A method for preparing graphene by assisted liquid phase exfoliation, mixing graphite powder and organic solvent evenly, adding it to a preheated reaction kettle, feeding it into the reaction kettle and continuously stirring, and starting the reaction after reaching the preset supercritical pressure; the reaction After the end, the reactor was cooled to CO 2 Below the critical point, CO is emitted 2 , the solution is taken out for ultrasonic treatment, and the supernatant is taken after centrifugation to obtain a graphene solution; the method of the present invention is simple to operate, mild in condition, high in product quality, and CO 2 Environmental protection, low cost, and less organic solvent consumption; therefore, this method is a technology for industrialized green production of graphene with practical application prospects.

Description

technical field

[0001] The invention belongs to the technical field of graphene preparation, in particular to a method of using supercritical CO 2 A method for preparing graphene with assisted liquid phase exfoliation. Background technique

[0002] As a member of the family of two-dimensional nanomaterials, graphene has a typical sheet structure, with horizontal dimensions ranging from several nanometers to several micrometers or even larger, but the thickness is only one or several atoms thick. Although the search for two-dimensional materials dates back decades, it was not until 2004 that marked the birth of graphene. How to achieve low-cost and large-scale preparation of high-quality graphene is still one of the main bottlenecks restricting the development of graphene industrialization at this stage. At present, the commonly used graphene preparation methods mainly include redox method, chemical vapor deposition (CVD) method and liquid phase exfoliation method. However...

Examples

Embodiment 1

[0024] (1) Weighing 60 mg of natural graphite powder and 60 mL of NMP to form a reaction solution with a concentration of 1 mg / mL, and ultrasonically mixing in a water bath for 10 minutes;

[0025] (2) Add the solution to figure 1 In the reaction kettle shown, after heating the reaction kettle to 40°C through the control module, turn on the mechanical stirring (1000rpm) and use the booster pump to pump the CO in the carbon dioxide bottle 2 Pump it into the reaction kettle, and the reaction will start after the pressure reaches 12MPa;

[0026] (3) After reacting for 2 hours, take out the reactor and place it in a water bath to cool to below 25°C, open the exhaust valve to let the CO 2 go through figure 1 After washing the bottle shown, pour the solution into the beaker;

[0027] (4) Ultrasonic disperse the taken-out solution for 45 minutes, pour it into a centrifuge tube and centrifuge at 2500rpm for 30 minutes, and then take the supernatant to obtain a graphene solution wit...

Embodiment 2

[0029] (1) Weigh 210mg of expandable graphite powder and 70mL of NMP to form a reaction solution with a concentration of 3mg / mL, and ultrasonically mix in a water bath for 5 minutes;

[0030] (2) Add the solution to figure 1 In the reaction kettle shown, after heating the reaction kettle to 50°C through the control module, turn on the magnetic stirring (1500rpm) and use the booster pump to remove the CO in the carbon dioxide bottle. 2 Pump it into the reaction kettle, and the reaction will start after the pressure reaches 16MPa;

[0031] (3) After reacting for 4 hours, take out the reaction kettle and place it in a water bath to cool to below 25°C, open the exhaust valve to drain the CO 2 go through figure 1 The indicated scrubber bottle is drained, and the solution is poured into a beaker;

[0032] (4) Ultrasonic disperse the taken-out solution for 45 minutes, pour it into a centrifuge tube and centrifuge at 2500 rpm for 30 minutes, and then take the supernatant to obtain ...

Embodiment 3

[0034] (1) Weigh 300mg of expandable graphite powder and 60mL of DMF to form a reaction solution with a concentration of 5mg / mL, and ultrasonically mix in a water bath for 15 minutes;

[0035] (2) Add the solution to a preheated to 80°C figure 1 In the reaction kettle, open the mechanical stirring (2000rpm) and utilize figure 1 The booster pump in the reactor feeds CO into the reactor 2 , the reaction starts after the pressure reaches 20MPa;

[0036] (3) After reacting for 6 hours, take out the reactor and place it in a water bath to cool to below 25°C, open the exhaust valve to drain the CO 2 go through figure 1 The washing bottle is discharged, and the solution is poured into the beaker;

[0037] (4) Ultrasonic disperse the taken-out solution for 60 minutes, pour it into a centrifuge tube and centrifuge at 2500 rpm for 30 minutes, and then take the supernatant to obtain a graphene solution with a concentration of 0.46 mg / mL. Graphene sheets with less than ten layers acc...

technical field

[0001] The invention belongs to the technical field of graphene preparation, in particular to a method of using supercritical CO 2 A method for preparing graphene with assisted liquid phase exfoliation. Background technique

[0002] As a member of the family of two-dimensional nanomaterials, graphene has a typical sheet structure, with horizontal dimensions ranging from several nanometers to several micrometers or even larger, but the thickness is only one or several atoms thick. Although the search for two-dimensional materials dates back decades, it was not until 2004 that marked the birth of graphene. How to achieve low-cost and large-scale preparation of high-quality graphene is still one of the main bottlenecks restricting the development of graphene industrialization at this stage. At present, the commonly used graphene preparation methods mainly include redox method, chemical vapor deposition (CVD) method and liquid phase exfoliation method. However...

Examples

Embodiment 1

[0024] (1) Weighing 60 mg of natural graphite powder and 60 mL of NMP to form a reaction solution with a concentration of 1 mg / mL, and ultrasonically mixing in a water bath for 10 minutes;

[0025] (2) Add the solution to figure 1 In the reaction kettle shown, after heating the reaction kettle to 40°C through the control module, turn on the mechanical stirring (1000rpm) and use the booster pump to pump the CO in the carbon dioxide bottle 2 Pump it into the reaction kettle, and the reaction will start after the pressure reaches 12MPa;

[0026] (3) After reacting for 2 hours, take out the reactor and place it in a water bath to cool to below 25°C, open the exhaust valve to let the CO 2 go through figure 1 After washing the bottle shown, pour the solution into the beaker;

[0027] (4) Ultrasonic disperse the taken-out solution for 45 minutes, pour it into a centrifuge tube and centrifuge at 2500rpm for 30 minutes, and then take the supernatant to obtain a graphene solution wit...

Embodiment 2

[0029] (1) Weigh 210mg of expandable graphite powder and 70mL of NMP to form a reaction solution with a concentration of 3mg / mL, and ultrasonically mix in a water bath for 5 minutes;

[0030] (2) Add the solution to figure 1 In the reaction kettle shown, after heating the reaction kettle to 50°C through the control module, turn on the magnetic stirring (1500rpm) and use the booster pump to remove the CO in the carbon dioxide bottle. 2 Pump it into the reaction kettle, and the reaction will start after the pressure reaches 16MPa;

[0031] (3) After reacting for 4 hours, take out the reaction kettle and place it in a water bath to cool to below 25°C, open the exhaust valve to drain the CO 2 go through figure 1 The indicated scrubber bottle is drained, and the solution is poured into a beaker;

[0032] (4) Ultrasonic disperse the taken-out solution for 45 minutes, pour it into a centrifuge tube and centrifuge at 2500 rpm for 30 minutes, and then take the supernatant to obtain ...

Embodiment 3

[0034] (1) Weigh 300mg of expandable graphite powder and 60mL of DMF to form a reaction solution with a concentration of 5mg / mL, and ultrasonically mix in a water bath for 15 minutes;

[0035] (2) Add the solution to a preheated to 80°C figure 1 In the reaction kettle, open the mechanical stirring (2000rpm) and utilize figure 1 The booster pump in the reactor feeds CO into the reactor 2 , the reaction starts after the pressure reaches 20MPa;

[0036] (3) After reacting for 6 hours, take out the reactor and place it in a water bath to cool to below 25°C, open the exhaust valve to drain the CO 2 go through figure 1 The washing bottle is discharged, and the solution is poured into the beaker;

[0037] (4) Ultrasonic disperse the taken-out solution for 60 minutes, pour it into a centrifuge tube and centrifuge at 2500 rpm for 30 minutes, and then take the supernatant to obtain a graphene solution with a concentration of 0.46 mg / mL. Graphene sheets with less than ten layers acc...

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