▎ 摘　　要

NOVELTY - Preparing size controllable graphene, comprises oxidizing crystalline flake graphite using concentrated sulfuric acid and concentrated nitric acid to obtain graphite intercalation compound, adopting thermal expansion technology to expand graphite intercalation compound, oxidizing the expanded graphite by adopting a modified Hummers method to obtain oxidized graphene, separating oxidized graphene by high-speed repeated centrifuging method, and precipitating the obtained oxidized graphene in different sizes on a substrate (quartz), and obtaining different sizes of graphene by reduction method. USE - The method is useful for preparing size controllable graphene (claimed). ADVANTAGE - The method produces graphene with different sizes in batch, whose maximal area reaches up to 20000 mu m2. DETAILED DESCRIPTION - Preparing size controllable graphene, comprises: (a) using crystalline flake graphite as raw material, using concentrated sulfuric acid and concentrated nitric acid for oxidizing crystalline flake graphite 2-48 hours and drying to obtain graphite intercalation compound, where the weight ratio of flake graphite, concentrated sulfuric acid and concentrated nitric acid is 1:28.8:6.5, (b) adopting thermal expansion technology to expand graphite intercalation compound at 950-1100 degrees C for 5-60 seconds to obtain expanded graphite, (c) oxidizing the expanded graphite by adopting a modified Hummers method to obtain oxidized graphene, (d) separating oxidized graphene through a high-speed repeated centrifuging method to obtain different sizes of oxidized graphene, and (e) precipitating the obtained oxidized graphene in different sizes on a substrate (quartz), and obtaining different sizes of graphene through high-temperature thermal reduction or low-temperature chemical reduction.