▎ 摘　　要

Graphene has no oxygen groups on its surface, resulting in a poor dispersion in water. The synthesis of graphene with high water solubility is popular nowadays. In this study, the oxygen content of graphite oxide was adjusted by a low-temperature and high-vacuum expansion process, the resultant graphene sheets exhibited the smallest thickness of about 1.7 nm and size of 1.0 mu m. The results indicated that prepared graphene could be stable in neutral aqueous solution without surfactant, and the solubility of the water-soluble graphene was 0.07 mg/mL. In addition, the electrical conductivity of the graphene film of around 1000 S/m was higher than many reported non-covalent graphene films.