▎ 摘　　要

NOVELTY - Reduction of graphene oxide involves measuring 12 mL sulfuric acid with a graduated cylinder, adding to 100 mL beaker, adding 2.5 g potassium persulfate and 2.5 g phosphorus pentoxide, dissolving, obtaining mixed solution, adding 3 g natural graphite, stirring, cooling to room temperature, diluting with 500 mL deionized water, filtering, obtaining pre-oxidized graphite sample, grinding, adding to 120 mL concentrated sulfuric acid, stirring, obtaining sulfuric acid solution of graphite sample, grinding 15 g potassium permanganate into powder, adding to sulfuric acid solution of the graphite sample, mixing, adding potassium permanganate, heating, oxidizing, diluting with 250 mL deionized water, stirring, adding 0.7 L deionized water and 20 mL hydrogen peroxide, reacting, obtaining graphene oxide mixed solution, separating and purifying graphene oxide mixed solution, centrifuging, and ultrasonically processing to obtain graphene oxide solution with concentration of 5 mg/mL or more. USE - Reduction of graphene oxide. ADVANTAGE - The method enables simple and economical reduction of graphene oxide by strictly controlling temperature conditions during oxidation reaction of potassium permanganate and dilution of deionized water, and provides graphene oxide sheet having large size and containing reduced oxidized functional groups. DETAILED DESCRIPTION - Reduction of graphene oxide involves measuring 12 mL sulfuric acid with a graduated cylinder, adding to 100 mL beaker, adding 2.5 g potassium persulfate and 2.5 g phosphorus pentoxide, dissolving, obtaining mixed solution, adding 3 g natural graphite, stirring at 80 degrees C, cooling to room temperature, diluting with 500 mL deionized water, obtaining layered solution, removing supernatant of resultant, filtering precipitate using 0.2 mm filter, removing impurities, drying in a vacuum drying oven at 60 degrees C, obtaining pre-oxidized graphite sample, grinding into powder, adding to 120 mL concentrated sulfuric acid with concentration of 98 wt.% or more, stirring, obtaining sulfuric acid solution of graphite sample, grinding 15 g potassium permanganate into powder in an agate mortar, adding to sulfuric acid solution of the graphite sample, mixing under ice bath conditions at 10 degrees C or less, adding potassium permanganate, heating to 35 degrees C or more, stirring for 2 hours or more, oxidizing, diluting with 250 mL deionized water in an ice bath, obtaining a diluted solution, stirring for 2 hours or more, adding 0.7 L deionized water and 20 mL hydrogen peroxide with concentration of 30 wt.%, reacting for 0.5 hour or more, obtaining graphene oxide mixed solution, separating and purifying graphene oxide mixed solution, leaving still, removing supernatant, adding 1 L deionized water to dilute, centrifuging in a centrifuge at 10000 rpm for 10 minutes, removing supernatant, placing resultant precipitate in a beaker, washing with hydrochloric acid with concentration of 10 wt.% or less to remove metal ions, centrifuging in centrifuge at 10000 rpm for 10 minutes or more, removing supernatant, washing with deionized water, repeating the centrifugation process 3 or more times, collecting precipitated graphene oxide, adding 1 L deionized water for dilution, and ultrasonically processing for 0.5 hour or more to obtain graphene oxide solution with concentration of 5 mg/mL or more.