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

Abstract

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.

Graphene oxide adsorption enhanced by in situ reduction with sodium hydrosulfite to remove acridine orange from aqueous solution

“…hydrazine [38] and hydroxylamine hydrochloride [13]. Previous studies have suggested possible mechanisms for the effects of sulfur-containing compounds [8,9,15]. We confirmed that the products contained SO 4 2-using the BaCl 2 method that indicates a positive based on a white precipitate, with findings consistent with those of Chen et al [8].…”

“…Previous studies have suggested possible mechanisms for the effects of sulfur-containing compounds [8,9,15]. We confirmed that the products contained SO 4 2-using the BaCl 2 method that indicates a positive based on a white precipitate, with findings consistent with those of Chen et al [8]. A possible mechanism involving sodium hydrosulfite is shown as follows, with some modifications of the mechanisms described by Zhou et al [15]:…”

“…The reaction between sodium borohydride and water produced a soda water-like effervescence. This hydrolysis of sodium borohydride resulted in decreased reduction efficiency [8]. For sodium hydrosulfite, however, a rapid darkening that appeared with its addition demonstrated its high effectiveness.…”

“…Both LRGO (69.3%) and SRGO (45.5%) are much more stable than GO (36.5%), as deduced by their residues. In general, mass loss throughout the procedure normally consists of two major steps, the small amount of inter-lamellar water evaporation as the initial weight loss and the functional group decomposition into gases between the intercalated layers [8]. The former could be used to explain the little peak on the TG-A curve at about 220C (not shown in Fig.…”

“…However, to date, chemically derived graphene oxide (GO) from graphite has revealed a variety of potential uses because of its flexibility and relatively cheap fabrication. Like a graphene precursor, a subsequent GO reduction could restore the sp 2 carbon structure via various methods such as annealing [4], solvothermal/hydrothermal processes [5][6][7], or different kinds of reductants [8][9][10][11][12][13][14][15]. However, compared to mechanical exfoliation, functionalities (as defects) can be meanwhile imperfectly introduced onto graphene sheet surfaces.…”