Graphene oxide and method of production thereof

Patent metadata

Field	Value
Publication number	US-2018362349-A1
Application number	US-201516061233-A
Country	US
Kind code	A1
Filing date	Dec 14, 2015
Priority date	Dec 14, 2015
Publication date	Dec 20, 2018
Grant date	—

Abstract

A method of producing an electrochemically derived graphene oxide and product produced therefrom. The method comprises locating graphite particles within an electrochemical cell having a working electrode, counter electrode, and an aqueous acid electrolyte, the working electrode being positioned within the electrolyte to contact at least a portion of the graphite particles; agitating the graphite particles within the electrolyte; and applying a potential difference between the working electrode and counter electrode, thereby resulting in electrochemical exfoliation and oxidation of the graphite particles to produce graphene oxide.

First claim

1 . A method of producing graphene oxide comprising:
locating graphite particles within an electrochemical cell having a working electrode, counter electrode, and an aqueous acid electrolyte, the working electrode being positioned within the electrolyte to contact at least a portion of the graphite particles; agitating the graphite particles within the electrolyte; and applying a potential difference between the working electrode and counter electrode, thereby resulting in electrochemical exfoliation and oxidation of the graphite particles to produce graphene oxide.

2 . A method according to claim 1 , wherein the graphite particles are agitated within the electrolyte by at least one of mechanical agitation, flow constriction or fluid flow characteristics.

3 . A method according to claim 2 , wherein mechanical agitation comprises stirring.

4 . A method according to claim 1 , wherein the agitation of the graphite particles within the electrolyte creates a shear force sufficient to assist in exfoliation of oxidised graphene layers.

5 . A method according to claim 1 , wherein agitation of the graphite particles within the electrolyte creates a flow velocity in the electrolyte of at least 0.1 m/s, preferably between 0.2 to 10 m/s, more preferably between 1 to 5 m/s.

6 . A method according to claim 1 , wherein agitation of the graphite particles within the electrolyte creates a graphite slurry vortex.

7 . A method according to claim 1 , wherein the working electrode comprises a receptacle within which the graphite particles are located, retained and separated from the counter electrode within the electrochemical cell.

8 . A method according to claim 1 , wherein the working electrode includes a membrane section having pores sized to retain graphite and GO particles within the working electrode.

9 . A method according to claim 1 , wherein the membrane section has a pore size of <2 μm, preferably <1 μm, more preferably <0.8 μm, more preferably around 0.6 μm.

10 . A method according to claim 1 , wherein the working electrode includes a conductive mesh.

11 . A method according to claim 10 , wherein the conductive mesh comprises a metal mesh, preferably a platinum mesh.

12 . A method according to claim 1 , wherein the counter electrode comprises a conductive body, preferably a metal body or carbon body.

13 . A method according to claim 1 , wherein the aqueous acidic electrolyte includes molecules and/or ion components which facilitate the intercalation of graphite layers of the graphite particles.

14 . A method according to claim 1 , wherein the aqueous acidic electrolyte is selected from sulphuric acid, perchloric acid, nitric acid, phosphoric acid or boric acid.

15 . A method according to claim 1 , wherein the graphite particles have an average particle size of from 10 μm to 25 mm, preferably from 50 μm to 10 mm, more preferably from 100 μm to 1 mm.

16 . A method according to claim 1 , wherein the graphite particles comprise graphite flakes.

17 . A method according to claim 1 , wherein the potential difference between the working electrode and counter electrode provide a current of at least 1 A therebetween.

18 . An apparatus for producing graphene oxide by electrochemical exfoliation of graphite particles, the apparatus including:
a fluid housing configured to house an aqueous acid electrolyte; a working electrode being positioned within the electrolyte and configured to engage graphite particles located in the apparatus; a counter electrode separated from the working electrode and graphite particles; a potentiostat for creating a potential difference between the working electrode and counter electrode; and an agitation arrangement, which in use, agitates the graphite particles within the electrolyte.

19 . An apparatus according to claim 18 , wherein the agitation arrangement comprises a mechanical agitation arrangement, preferably a stirring arrangement.

20 . An apparatus according to claim 18 , wherein the working electrode comprises a receptacle within which the graphite particles are fed, retained and separated from the counter electrode within the electrochemical cell.

21 . An apparatus according to claim 18 , wherein the working electrode includes a membrane section sized to retain graphite and GO particles within the working electrode.

22 . An apparatus according to claim 18 , wherein the working electrode includes a conductive mesh.

23 . An apparatus according to claim 22 , wherein the conductive mesh comprises a metal mesh, preferably a platinum mesh.

24 . An apparatus according to claim 18 , wherein the counter electrode comprises a conductive body, preferably a metal body or carbon body.

25 . An apparatus according to claim 18 , wherein the aqueous acidic electrolyte is selected from sulphuric acid, perchloric acid, nitric acid, phosphoric acid or boric acid.

26 . A graphene oxide formed from the method according to claim 1 .

27 . An electrochemically derived graphene oxide comprising oxygen functionalities that essentially consist of hydroxy and epoxy groups.

28 . An electrochemically derived graphene oxide according to claim 27 , wherein the electrochemically derived graphene oxide is a substantially single layer graphene oxide.

29 . An electrochemically derived graphene oxide according to claim 27 , wherein the oxygen functionalities comprise less than 5% carbonyl groups, preferably less than 1% carbonyl groups, more preferably less than 0.05% carbonyl groups, preferably less than 0.01% carbonyl groups.

30 . An electrochemically derived graphene oxide according to claim 27 , wherein the mass fraction of monolayer graphene oxide sheets is between 30 and 40 wt %, preferably between 30 and 35 wt %, more preferably about 33 wt %.

31 . An electrochemically derived graphene oxide according to claim 27 , wherein the electrochemically derived graphene oxide comprises:
20 to 25 atom % oxygen, preferably from 20 to 22 atom % oxygen; and 74 to 78 atom % carbon, preferably from 75 to 77 atom % carbon

32 . An electrochemically derived graphene oxide according to claim 27 , wherein the graphene oxide has a dispersibility of up to 1 mg/mL in water.

33 . An electrochemically derived graphene oxide according to claim 27 , wherein the graphene oxide can undergo thermal reduction at temperatures between 150 to 400° C., preferably 150 to 250° C., more preferably about 200° C. to form a highly conductive graphene product.

34 . An electrochemically derived graphene oxide according to claim 33 , wherein the conductivity of the graphene product is from 10 2 to 10 3 S·m −1 .

35 . An electrochemically derived graphene oxide comprising oxygen functionalities that essentially consist of hydroxy and epoxy groups formed from the method according to claim 1 .

Assignees

• Baoshan Iron & Steel

Inventors

• Zhong Yulin
• Li Dan
• Simon George Philip

Classifications

• C25B13/02

  characterised by shape or form · CPC title

• C01B32/23

  Oxidation · CPC title

• C01B32/19 Primary

  by exfoliation · CPC title

• C01B2204/22

  Electronic properties · CPC title

• C01B32/198 Primary

  Graphene oxide · CPC title