Ltd. The slurry was frozen overnight before freeze-drying to produce a dehydrated powder, which was blended and sieved to < 50 m. FGO was prepared using plasma-fluorination. The Haydale HT-60 lab scale reactor was used to process a 25g batch of material in a CF 4 plasma, at low temperatures (<100 °C) and pressures (<1 mbar). A detailed characterisation of the GO and FGO powders is provided in ESI (Figures , Table ).