Chemical Reduction of Graphene Oxide to Graphene by Sulfur-Containing Compounds

Instead of hydrazine, a series of sulfur-containing compounds such as NaHSO 3, Na 2 SO 3, Na 2 S 2 O 3, Na 2 S·9H 2 O, SOCl 2, and SO 2, were used as reducing agents to reduce graphene oxide to graphene. Fourier transform infrared spectrometry, atomic force microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, elemental analysis, and thermogravimetric analysis confirmed the formation of graphene under chemical reduction at 95 °C. The results reveal that the reducing ability of NaHSO 3 is comparable to that of hydrazine. This newly found reducing agent is of low toxicity and nonvolatile, which makes the reduction much safer than hydrazine. A possible mechanism of the reduction has been suggested. The electrical conductivity of the graphene paper prepared using a NaHSO 3 reducing agent is found to be 6500 S m −1, while it is observed to be 5100 S m −1 for hydrazine-reduced graphene paper. These studies also confirmed that SOCl 2 can be a good candidate as a reducing agent to compete with hydrazine.