Synthesis of few-layer graphene-like sheets from carbon-based powders via electrochemical exfoliation, using carbon black as an example

In electrochemical exfoliation, the working electrode is typically a graphite rod or foil, or highly oriented pyrolytic graphite. These electrodes are limited by the surface area that is in contact with the electrolyte and available for exfoliation. In contrast, a powder-based carbon material will have a much larger surface area exposed to the electrolyte, thus leading to an efficient exfoliation process and faster production of graphene. Herein, we have demonstrated the synthesis of few-layer graphene-like (FLG) sheets from carbon black widely available as a fine powder in its native form. It is challenging to run an electric current through a powdery material. Thus, we proposed to bind the carbon black particles together using a pH-independent intrinsically electrically conducting polymer to form a porous working electrode. Raman spectroscopy confirmed the synthesis of FLG from powder-based carbon black. The thickness of our FLG sheets was determined by atomic force microscopy to be between 3 and 8 nm. Transmission electron microscopy revealed that the sheets were ~35 nm in length and ~30 nm in width, similar to the particle size of the carbon black (~50 nm in diameter) starting material. The synthesized FLG was compared to industry standards and found to be of excellent quality. Glass coated with our FLG has a transparency of 85–90% in the 300- to 1000-nm wavelength region. The present study serves as a foundation for the electrochemical synthesis of graphene from various carbonaceous powders generated by many industries.