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

Instead of hydrazine, a series of sulfur-containing compounds such as NaHSO3, Na2SO3, Na2S2O3, Na2S center dot 9H(2)O, SOCl2, and SO2, were used as reducing agents to reduce graphene oxide to graphene. Fourier transfoim 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 degrees C. The results reveal that the reducing ability of NaHSO3 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 NaHSO3 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 SOCl2 can be a good candidate as a reducing agent to compete with hydrazine.