We describe the direct electro-chemical reduction of graphene oxide to graphene from aqueous suspension by applying reduction voltages exceeding -1.0 to -1.2 V. The conductivity of the deposition medium is of crucial importance and only values between 4-25 mS cm(-1) result in deposition. Above 25 mS cm(-1) the suspension de-stabilises while conductivities below 4 mS cm(-1) do not show a measurable deposition rate. Furthermore, we show that deposition can be carried out over a wide pH region ranging from 1.5 to 12.5. The electro-deposition process is characterised in terms of electro-chemical methods including cyclic voltammetry, quartz crystal microbalance, impedance spectroscopy, constant amperometry and potentiometric titrations, while the deposits are analysed via Raman spectroscopy, infra-red spectroscopy, X-ray photoelectron spectroscopy and X-ray diffractometry. The determined oxygen contents are similar to those of chemically reduced graphene oxide, and the conductivity of the deposits was found to be similar to 20 S cm(-1).
Hilder, M., Winther-Jensen, B., Forsyth, M., & Macfarlane, D. (2011). Direct electro-deposition of graphene from aqueous suspensions. Physical Chemistry Chemical Physics, 13(20), 9187 - 9193. https://doi.org/10.1039/c1cp20173e