Preparation method of graphene and graphene oxide based on mixed acid system

摘要

The present invention relates to a preparation method of graphene oxide based on mixed acid system. The method consists of the following steps. a. Preparation of graphite powder; b. Preparation of suspension liquid of first acid system; c. Preparation of second acid system; d. Preparation of graphene oxide. The invention also relates to a preparation method of graphene using graphene oxide obtained by method mentioned above. The method consists of the following steps. e. Preparation of graphene oxide-dispersant solution; f. Reduction of graphene oxide; g. Process of supersonic stripping; h. Obtaining graphene by separation and drying. The preparation methods of graphene oxide and graphene in our invention could reduce the dosage of strong acid as well as heat release of chemical reaction, and cause less corrosion to our equipments, which makes the reaction more effective and properties of graphene products better, facilitating the achievement of large scale industrial production.

主权项

1. A method of preparing graphene oxide based on mixed acid system, comprising:
a. a preparation of graphite powder: washing, drying, and grinding raw material of graphite; sieving the ground graphite through a 200-mesh sieve to obtain graphite powder; and wherein the raw material of graphite is crystalline flake graphite; b. a preparation of a first acid system: mixing the graphite powder with an intercalator to obtain a first mixture; conducting an ultrasonic process on the first mixture; wherein said intercalator is a first acid composition: providing a first dispersion including the graphite and a first acid composition, a mass concentration of the graphite being 0.1-1 g/ml; wherein said first acid composition includes at least one acid selected from the group consisting of organic strong acid and inorganic strong acid; and conducting an ultrasonic stirring process on the first dispersion for 0.5-3 hours, to obtain the first acid system; c. a preparation of a second acid system: grinding an oxidant; solving the ground oxidant into a second acid composition at a temperature of 40-60° C., to obtain a first solution with a mass concentration of the oxidant of 0.5-5 g/ml: wherein the second acid composition is an organic weak acid, or an inorganic weak acid, or a mixture thereof; adding a long-chain organic acid into the first solution to obtain a second solution; wherein a mass ratio of the graphite powder to the long-chain organic acid is 100:0.1-1; wherein the long-chain organic acid is a saturated organic acid with carbon atoms more than C10: conducting an ultrasonic treatment on the second solution for 0.5 hours; and naturally cooling the second solution to obtain the second acid system; d. a preparation of a graphene oxide: adding the first acid system into the second acid system drop by drop with a rate of 1-2 drops per second to obtain a second mixture; wherein a volume of the first acid system added to the second acid system is calculated according to a first formula:Cgraphite×Vthe⁢⁢first⁢⁢acid⁢⁢systemCoxidant×Vthe⁢⁢second⁢⁢acid⁢⁢system=1⁢:⁢⁢2⁢-⁢8 wherein Cgraphite is the mass concentration of the graphite in the first dispersion, wherein Vthe first acid system represents the volume of the first acid system, wherein Coxidant represents the mass concentration of oxidant in the first solution, and wherein Vthe second acid system represents a volume of the second acid system into which the first acid system is added: conducting the ultrasonic stirring process on the second mixture for 0.5-3 hours; dissolving the second mixture into water drop by drop at an environment temperature of 70-100° C.; keeping the second mixture still for 3-10 min to obtain a combined liquid; wherein a volume of water is calculated according to a second formula:Cgraphite×Vthe⁢⁢first⁢⁢acid⁢⁢systemρwater×Vwater=1⁢:⁢⁢20⁢-⁢50 wherein Cgraphite is the mass concentration of the graphite in the first dispersion, wherein Vthe first acid system represents the volume of the first acid system, wherein ρwater represents a density of water, and wherein Vwater represents the volume of water; conducting the ultrasonic stirring process on the combined liquid for 0.5-3 hours; conducting a centrifuging process on the combined liquid at a rate of 4000 r/min for 5 min to obtain a supernatant; adding an ammonium sulfate solution with a mass concentration of 2-5% into the supernatant to obtain a third solution; salting out the third solution to obtain a fourth solution; suction filtrating the fourth solution to obtain a filter cake; washing the filter cake with deionized water; alcohol washing the filter cake: and drying the filter cake to obtain the graphene oxide.