Pristine graphite oxide retains its C-axis registry in methanol. The way to alternative purification method

Abstract

In this work, we demonstrate that pristine graphite oxide (PGO), formed by the oxidation of graphite by the modified Hummers’ method, when still in synthetic mixture, can be re-intercalated by methanol, while keeping its c-axis registry. The as-formed structure contains two molecular layers of methanol, sandwiched between the neighboring graphene oxide (GO) sheets. The typical water-washed and dried GO intercalates only by one molecular layer of methanol. This finding suggests the route for preparing alcohol-intercalated GO straight from PGO, while bypassing water-purification, drying, and intercalating steps. The methanol-purified GO has significantly higher content of organic sulfates, compared to the typical water-purified sample. We stress one more time that the 1620 cm−1 and 1223 cm−1 absorption bands in the FTIR spectra of GO are originated by water molecules, and organic sulfates, respectively. The GO purification with methanol has some advantages over the currently used water-purification, and might become an attractive alternative to the latter.