| Abstract
| - We present a theoretical description of the kinetics of electrochemical charge transfer at single-walled carbon nanotube (SWNT) electrodes, explicitly taking into account the SWNT electronic bandstructure. SWNTs have a distinct and low density of electronic states (DOS), as expressed by a smallvalue of the quantum capacitance. We show that this greatly affects the alignment and occupation ofelectronic states in voltammetric experiments and thus the electrode kinetics. We model electrochemistryat metallic and semiconducting SWNTs as well as at graphene by applying the Gerischer−Marcus modelof electron transfer kinetics. We predict that the semiconducting or metallic SWNT band structure and itsdistinct van Hove singularities can be resolved in voltammetry, in a manner analogous to scanning tunnelingspectroscopy. Consequently, SWNTs of different atomic structure yield different rate constants due tostructure-dependent variations in the DOS. Interestingly, the rate of charge transfer does not necessarilyvanish in the band gap of a semiconducting SWNT, due to significant contributions from states which area few kBT away from the Fermi level. The combination of a nanometer critical dimension and the distinctband structure makes SWNTs a model system for studying the effect of the electronic structure of theelectrode on electrochemical charge transfer.
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