▎ 摘　　要

NOVELTY - Preparing graphene oxide microsphere comprises (i) preparing graphene oxide by modified Hummer's method, dispersing in deionized water, and configuring as mass fraction of 0.2-6% graphene oxide dispersion, (ii) placing graphene oxide dispersion in hopper of spray gun, spraying into ball at pressure of 0.4-0.8 MPa, and freezing in liquid nitrogen to obtain graphene oxide microsphere, and (iii) freeze-drying for not less than 4 hours and shaping to obtain graphene oxide microsphere. USE - The microsphere is useful in preparing graphene microsphere, chitosan-graphene oxide microsphere and nitrogen-doped graphene microsphere (all claimed). ADVANTAGE - The microsphere has simple preparation process, low cost and short time consumption; is environmentally friendly. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for: (1) preparing graphene microsphere comprising performing high-temperature carbonization of graphene oxide microsphere to obtain graphene microsphere; (2) preparing chitosan-graphene oxide microsphere comprising mixing 0.2-6 wt.% graphene oxide solution and 1-2 wt.% chitosan solution in mass ratio of 9:1 to obtain dispersion, then adding 0.1 M sodium hydroxide solution into dispersion to make alkaline, ultrasonically dispersing for 10-20 minutes, dialyzing for 48 hours, placing dispersion in spray gun hopper, spraying into ball at pressure of 0.4-0.8 MPa, and freezing-drying for not less than 4 hours in liquid nitrogen to obtain chitosan-graphene oxide microsphere, then shaping freeze-dried chitosan-graphene oxide microsphere; and (3) preparing nitrogen-doped graphene microsphere comprises placing chitosan-graphene oxide microsphere in tube furnace, heating at 400-1000 degrees C at rate of 2-5 degrees C/minute for 2-2.5 hours, and naturally cooling to obtain nitrogen-doped graphene microsphere.