▎ 摘　　要

NOVELTY - Preparation of insoluble graphene involves uniformly mixing expanded graphite, sodium persulfate, sodium vanadate and vanadoheteropolyacid, reacting at room temperature, performing vacuum filtration of the resultant reaction mixture, washing the filter cake to neutral, naturally drying, oxidizing, obtaining graphene oxide, performing suction filtration, washing the filter cake with deionized water to neutral, reducing, drying and obtaining sheet of solid reduced graphene oxide. USE - Preparation of insoluble graphene (claimed). ADVANTAGE - The method provides insoluble graphene having excellent stability, by simple, economical and environmentally-friendly process without addition of photocatalyst or reducing agent.