Basic surface oxides on carbon materials:: A global view

Herein we report results from quantum chemical calculations on a large series of pyrone-like model compounds which are relevant for carbon basicity. In consonance with previous work (Carbon 1999, 37, 1002), pyrone-like functionalities at the edge of graphene layers are predicted to exhibit a broad range of pK(a) values (4-13) depending on the relative position of the ketone and etheric rings. The thermodynamic stability of pyrones is discussed in terms of reaction energies calculated for selected isodesmic processes which give insight into the role of the adjacent basal plane, the relative abundance of polycyclic pyrone-like structures, and so forth. In addition, we show that hypothetical redox processes involving pyrone-like structures have estimated electrochemical potentials which lie in the range of those observed in many carbons. Finally, the ability of pyrone-like model compounds to provide a global view of the chemical and electrochemical properties of basic carbon surfaces is discussed.