Reduction and structural evolution of graphene oxide sheets under hydrothermal treatment

•Reduced graphene oxide (RGO) suspensions were successfully prepared by hydrothermal approach.•The hydrothermal reducing process work investigated by FT-IR UV–Vis and TEM.•This reducing process was undergone four steps and the optimal condition was treated by hydrothermal process at 180 °C for 24 h.

This work carefully investigated the hydrothermal reduction of graphene oxide (GO) sheets. To evaluate the reduced extent, the as-prepared GO and RGO sheets in different conditions were measured by FT-IR, UV–Vis, Raman spectra and TEM morphologies. It revealed that the hydrothermal reduction of GO sheets was undergone four steps and the optimal condition was treated at 180 °C for 24 h. These RGO sheets exhibited the expectant morphologies and maintained the original sizes.