A simple method to modify thermal-exfoliated graphene nanosheets (T-GNS) by using streaming ozone
under different time and temperature is described in this paper. The results indicated that a wide variety
of oxygen-containing groups such as CAOH, CAOAC, C@O and COOH could be introduced on the surface
of T-GNS by ozone treatment. Especially when ozone modification was taken under 80 C for 20 min, the
atomic ratio of O/C was increased to 0.503, and the percentage of carboxyl groups was up to 14.37%,
which was more than 10 times compared with the original T-GNS. In addition, it is worth mentioning that
ozone treatment under a moderate temperature could cause etching on the edge of T-GNS and form
porous structure in basal plane. As a result, the dispersion of ozone-treated T-GNS in aqueous solution
was greatly improved, and the enhanced oxygen-containing groups and dispersion would facilitate its
further functionalization and application.