Method for preparing nano-graphene oxide by electrochemically exfoliating carbon fiber material
The present disclosure relates to the technical field of nano materials and aims to provide to a method for preparing nano-graphene oxide by electrochemically exfoliating a carbon fiber material. The method includes the following steps: building an electrochemical reaction system by using a raw material with a carbon fiber as a basic structural unit as an anode, a metal or graphitic carbon material as a cathode, and a phosphate buffer solution with a neutral pH as an electrolyte; in an electrolysis process, gradually exfoliating a carbon fiber in the anode raw material and dispersing the carbon fiber in the electrolyte solution to generate graphene oxide; centrifuging to separate the reacted electrolyte solution, taking upper dispersion liquid, and washing away residual anions and cations; and performing ultrasonic treatment to obtain nano-graphene oxide dispersed in water and free of impurities.
1 . A method for preparing nano-graphene oxide by electrochemically exfoliating a carbon fiber material, comprising the following steps:
(1) building an electrochemical reaction system, consisting of:
a raw material with a carbon fiber as a basic structural unit as an anode, a metal or graphitic carbon material as a cathode, and a phosphate buffer solution with a neutral pH as an electrolyte solution in which a concentration of PO 4 3− is 50-500 mmol/L;
(2) electrochemically exfoliating the carbon fiber;
during an electrolysis process, controlling a voltage between the anode and the cathode to be 3-10 V, and performing electrolysis for 8-24 h; and gradually exfoliating the carbon fiber in the anode raw material and dispersing the carbon fiber in the electrolyte solution to generate graphene oxide; and
(3) performing purification to obtain the nano-graphene oxide;
centrifuging to separate the reacted electrolyte solution, taking upper dispersion liquid, and washing away residual anions and cations; and performing ultrasonic treatment to obtain the nano-graphene oxide dispersed in water and free of impurities.
2 . The method according to claim 1 , wherein in step (1), a single-bundle fiber in the carbon fiber has a radial size of 10 μm or below.
3 . The method according to claim 1 , wherein in step (1), the raw material with the carbon fiber as the basic structural unit refers to carbon fiber cloth, a carbon fiber felt, a carbon fiber brush or carbon fiber paper made of a carbon fiber.
4 . The method according to claim 1 , wherein in step (1), the phosphate buffer solution has a pH of 7.
5 . The method according to claim 1 , wherein in step (1), the electrolyte is the phosphate buffer solution prepared from sodium dihydrogen phosphate and disodium hydrogen phosphate, or dipotassium hydrogen phosphate and sodium dihydrogen phosphate.
6 . The method according to claim 1 , wherein in step (1), the electrochemical reaction system is a two-electrode system or a three-electrode system; when the two-electrode system is used, the voltage between the cathode and the anode is controlled within a range of 3-10 V; and when the three-electrode system is used, an Ag/AgCl electrode filled with saturated KCl is used as a reference electrode, in the reaction process, the potential of the anode corresponding to the reference electrode is 1.6-3 V, and the voltage of the cathode and the anode is 3-10 V correspondingly.
7 . The method according to claim 1 , wherein in step (3), the dispersion liquid is washed by dialysis to remove the residual anions and cations.
8 . The method according to claim 1 , wherein in step (3), the ultrasonic treatment is performed at an ultrasonic power controlled to be 200-400 W for 10-60 min.
9 . The method according to claim 1 , wherein in step (3), the finally obtained nano-graphene oxide has a lateral size below 1 μm.