▎ 摘　　要

NOVELTY - The method for preparation of oxidized graphene, involves adding graphite powder, sulfuric acid and protective agent, adding potassium permanganate oxidizing agent, cooling, adding hydrogen peroxide until the mixture changes from purple to bright yellow, centrifugal washing, dialyzing to obtain brown oxidized graphite, adding oxidized graphite to deionized water, ultrasonically processing to obtain uniform dispersion of graphite oxide solution, adding hydrazine hydrate, ultrasonically dispersing to obtain graphene oxide suspension and freeze-drying to obtain graphene oxide. USE - Method for preparation of oxidized graphene with controllable graded degree. ADVANTAGE - The method enables simple preparation of environmentally-friendly oxidized graphene with short preparation time, high production efficiency and practicality, and controls the defect degree of graphene oxide by adding different amounts of protective agent. DETAILED DESCRIPTION - Method for preparation of oxidized graphene with controllable graded degree, involves adding graphite powder to three-necked flask, adding 98% concentrated sulfuric acid and protective agent in a molar ratio of 1:1.5-3.0, adding potassium permanganate oxidizing agent under ice bath condition, controlling the reaction temperature at not more than 10 degrees C, stirring for a period of time, maintaining the temperature at 40-60 degrees C for 10-12 hours, cooling the mixture to room temperature, pouring on ice, adding 25-35 wt.% hydrogen peroxide until the mixture changes from purple to bright yellow, centrifugal washing for 4-6 times to remove residue, placing in dialysis bag, dialyzing for 20-22 days after drying to constant weight, obtaining brown oxidized graphite, adding oxidized graphite to deionized water, ultrasonically processing to obtain uniform dispersion of graphite oxide solution, adding hydrazine hydrate, refluxing at 77-83 degrees C for 15-24 hours, ultrasonically dispersing to obtain stable dispersion of graphene oxide suspension and freeze-drying to obtain graphene oxide.