▎ 摘　　要

NOVELTY - Method for producing graphene with three-dimensional network structure, involves dispersing worm-like expanded graphite in dimethylformamide, ultrasonically processing, filtering, washing, drying to obtain expanded graphite, adding into sulfuric acid and phosphoric acid mixture, stirring, adding potassium permanganate, heating, stirring to obtain brown-green oxidized graphite, adding hydrogen peroxide, stirring, washing, centrifuging and drying to obtain oxidized expanded graphite, dispersing in water, adjusting pH, adding hydrazine hydrate, reacting, washing, filtering and drying. USE - Method for producing graphene with three-dimensional network structure, for use in preparation of graphene-based composite materials. ADVANTAGE - The graphene with regular three-dimensional network structure is obtained with fewer layers, so as to easy to introduce a variety of groups such as metal oxides and drugs into the void, and thus graphene-based composite materials modified by various groups are prepared efficiently. DETAILED DESCRIPTION - Method for producing graphene with three-dimensional network structure, involves (i) dispersing graphite powder in mixed acid of phosphoric acid and nitric acid, adding a strong oxidizing agent potassium permanganate, reacting at 25-30 degrees C for 1-1.5 hours, filtering, washing, drying to obtain acidified graphite, (ii) dispersing the acidified graphite in a mixed acid of acetic acid and nitric acid, adding potassium permanganate, reacting at 25-30 degrees C for 1-1.5 hours, filtering, washing and drying to obtain expandable graphite, (iii) heating expandable graphite in a muffle furnace at 900-950 degrees C for 25-30 seconds to obtain worm-like expanded graphite, dispersing the worm-like expanded graphite in dimethylformamide, ultrasonically processing for 20-24 hours to obtain expanded graphite dispersion liquid, filtering, washing and drying to obtain expanded graphite, (iv) adding the expanded graphite into a mixed acid of sulfuric acid and phosphoric acid, stirring at 0-5 degrees C, adding potassium permanganate under stirring condition, then heating at 50-55 degrees C, continually stirring for 10-12 hours to obtain brown-green oxidized graphite, placing in an ice bath, adding hydrogen peroxide, stirring until the solution is turned into golden, washing with hydrochloric acid, then repeatedly washing with ethanol and water, carrying out centrifugation and drying to obtain oxidized expanded graphite, (v) dispersing the oxidized expanded graphite in water, adjusting the pH of the solution to 12-13, then adding hydrazine hydrate, placing in a hydrothermal reactor, carrying out reaction at 180-200 degrees C for 10-12 hours, washing, filtering, and drying to obtain network-like graphene.