Temperature dependence of graphene oxide reduced by hydrazine hydrate

Abstract

Graphene oxide (GO) was successfully prepared by a modified Hummer's method. The reduction effect and mechanism of the as-prepared GO reduced with hydrazine hydrate at different temperatures and time were characterized by x-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), elemental analysis (EA), x-ray diffractions (XRD), Raman spectroscopy and thermo-gravimetric analysis (TGA). The results showed that the reduction effect of GO mainly depended on treatment temperature instead of treatment time. Desirable reduction of GO can only be obtained at high treatment temperature. Reduced at 95 °C for 3 h, the C/O atomic ratio of GO increased from 3.1 to 15.1, which was impossible to obtain at low temperatures, such as 80, 60 or 15 °C, even for longer reduction time. XPS, 13C NMR and FTIR results show that most of the epoxide groups bonded to graphite during the oxidation were removed from GO and form the sp(2) structure after being reduced by hydrazine hydrate at high temperature (>60 °C), leading to the electric conductivity of GO increasing from 1.5 × 10(-6) to 5 S cm(-1), while the hydroxyls on the surface of GO were not removed by hydrazine hydrate even at high temperature. Additionally, the FTIR, XRD and Raman spectrum indicate that the GO reduced by hydrazine hydrate can not be entirely restored to the pristine graphite structures. XPS and FTIR data also suggest that carbonyl and carboxyl groups can be reduced by hydrazine hydrate and possibly form hydrazone, but not a C = C structure.

Comprehensive review on synthesis and adsorption behaviors of graphene-based materials

“…To synthesize graphene, the reduction of graphene oxide by chemical methods has been carried out using reducing agents, such as hydrazine [49][50][51][52], dimethylhydrazine [53], hydroquinone [54], and NaBH 4 [55,56]. A proposed reaction pathway for epoxide reduction with hydrazine is presented in Fig.…”

Graphene-Like Layers from Unconventional Carbon Sources: New Perspectives on Hybrid Materials and π-system Synergisms

“…In GO treatment, the reduction is an essential step in order to transform it back into a conductive graphitic material as a consequence of the partial restoration of the graphitic structure. The solution route through chem-ical reduction with hydrazine is the more advantageous one because a large amount of GO in the solution phase can be easily converted to graphenelike nanosheets through the partial removal of oxygenated functional groups present in the structure of GO [60,61]. We adopted a similar procedure for GLox.…”

Remarkable Stability of Graphene/Ni-Al Layered Double Hydroxide Hybrid Composites for Electrochemical Capacitor Electrodes

“…The GO shows multiple peaks in the range of 1000-1750 cm 1 , indicating that oxygen-containing functional groups are founded such as hydroxyl, epoxy, carbonyl, and carboxyl groups. 24) In addition, a broad band at 3450 cm -1 can be observed, corresponding to the O-H vibration of graphene oxide. After reduction, these peaks disappear.…”