Fundamental Electrochemistry of Graphene

When graphene is immobilised upon an electrode surface, as is common practice in the literature to electrically wire (connect to) graphene and study its electrochemical activity, a heterogeneous electrode surface is formed. In this scenario, if we consider that a HOPG surface is utilised. Fig. 3.12 shows that four key sites 

In the case of immobilising graphene upon a metallic electrode as is sometimes spuriously undertaken, such as a gold macroelectrode, there would be three key electrochemical sites, the underlying gold and modified graphene with 

Elecirode Material 3 Graphene Edge Plane Sites 

Electrode Material 4 Graphene Basal Plane Sites 

Wet etch of AI2O3 to expose graphene and contact pads 

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In the liquid phase the topics of principal concern are adsorption and proton and/or electron transfer across the electric donble layer. Carbon materials are unique in these applications becanse they are insolnble over the entire practical range of pH, are amphoteric, and can exhibit either acidic or basic properties this was illustrated in Fignre 1.10. Furthermore, because of their more or less extensive delocalized k-electron system in the graphene layer, they can either accept or donate electrons. Snch remarkable flexibility offers, on the one hand, a nniqne opportnnity to tailor carbon s properties to specific needs in adsorption, catalysis, and electrocatalysis but, as argued in detail elsewhere [24], it is also responsible for the persistent lack of fundamental nnderstanding in the increasingly important field of carbon electrochemistry, despite the tremendous amount of research and development focused on carbon-based capacitors, batteries, and fnel cells. 

FIGURE 9.3 Some common values of and for selected carbon materials. (Brownson, D.A.C., Kampouris, D.K., and Banks, C.E., Graphene electrochemistry Fundamental concepts through to prominent applications, Chem. Soc. Rev., 41, 6944-6976, 2012. Reproduced by permission of The Royal Society of Chemistry.)... 

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