Diamond and Carbon Materials

Since the groundbreaking article in Science in October 2004 describing the occurrence, isolation and potential significance of graphene, there has been a huge interest in developing industrially scalable methods of manufacture from bottom-up and

top-down routes. By mid-2015 the number of international patent applications had already exceeded 10,000 and the annual rate

was continuing to accelerate exponentially. Over 11,000 scientific papers (more than one per hour) with “graphene” in the title were published in 2015. Hundreds of millions of dollars are being invested in such programs as Europe’s Graphene Flagship consortium as well in in many other academic and commercial organizations globally, although this far exceeds the current annual revenue of graphene producers, by an order of magnitude or more.

One such top-down route developed for the mass manufacture of graphene involves electrochemical exfoliation. Promising in its own right, this can be performed using diazonium salts at a single applied potential, simultaneously functionalizing the single- or few-layer graphene generated. Not only does this remove the need for the secondary processing step, it is also a particularly effective means of separating the functionalized layers by virtue of the nitrogen generated during the in-situ diazonium reduction.

Most typically for other top-down methods for production of graphene, functionalization is considered a separate, but

necessary, operation to permit dispersion, so this method appears to offer some clear economic advantages. Although the

method applies to a plurality of diazonium salts, nitrobenzenediazonium (NBD) salts are particularly effective as

demonstrated by quantitative assessment of dispersibility and efficacy in improving capacitance at the laboratory scale.

This presentation will review the current status of the graphene industry and specifically review the recent progress on

electrochemical exfoliation in this context.