▎ 摘　　要

The graphite oxide (GO) was prepared from purified natural flake graphite by the modified Hummers method. The colloidal form of graphene was subsequently prepared by ultrasonicating GO in the presence of hydrazine hydrate. The samples were characterized by using FTIR, Raman, Scanning Probe Microscopy (SPM) and zeta potential technique. The results suggest that the graphite is oxidized to covalent bond-type graphite intercalation compounds with various oxygen bearing functional groups (C=O, C-O, C-OH, -COOH and C-O-C). FTIR spectra show that the surface functional groups of graphite and graphene are almost the same. Graphene oxide and graphene can readily form stable aqueous colloids in water or in alkali solution with uniform sheet thickness of 1 nm. The factors affecting reduction degree and stability of graphene were discussed in reduction process, such as hydrazine hydrate dosage, reaction time and pH value in system. Reduction degree of graphene is mainly controlled by hydrazine hydrate dosage, reaction time in system while the stability is mainly affected by the pH value.