title: Single Nanotube Voltammetry: Current Fluctuations Are Due to Physical Motion of the Nanotube.
abstract: Nanoimpacts of single palladium-coated carbon nanotubes on a gold substrate are studied to elucidate the origins of the fluctuation in the current-time response of the hydrogen oxidation reaction mediated at its surface. The chronoamperometric and cyclic voltammetric responses from a single nanotube immobilized on the gold surface were compared to analogous data on a carbon substrate to determine the possible influence of substrate material on the nanotube-electrode electrical contact. No significant distinction between the gold and carbon was found, indicating in light of the considerable differences in the substrate materials' intrinsic electronic structures that it is the nanomotion of a nanotube at the electrode surface which is likely responsible for the observed current modulation. This nanomotion creates a varying contact resistance, to which the noise in the current-time signal of the mediated reaction is attributed. In addition, stochastic ex-situ adsorption of single nanotubes onto the gold electrode followed by careful drying of the electrode surface was found to drastically reduce the current fluctuation, again implying that a contact resistance arising from physical motion of the nanotube at the electrode is responsible for the modulation of current.
authors.affiliation: Department of Chemistry, Physical and Theoretical Chemistry Laboratory, Oxford University , South Parks Road, Oxford OX1 3QZ, United Kingdom.
authors.forename: Hannah
authors.initials: H
authors.lastname: Hodson
authors.affiliation: Department of Chemistry, Physical and Theoretical Chemistry Laboratory, Oxford University , South Parks Road, Oxford OX1 3QZ, United Kingdom.
authors.forename: Xiuting
authors.initials: X
authors.lastname: Li
authors.affiliation: Department of Chemistry, Physical and Theoretical Chemistry Laboratory, Oxford University , South Parks Road, Oxford OX1 3QZ, United Kingdom.
authors.forename: Christopher
authors.initials: C
authors.lastname: Batchelor-McAuley
authors.affiliation: Shanghai Key Laboratory of Materials Protection and Advanced Materials in Electric Power, Shanghai University of Electric Power , 2103 Pingliang Road, Shanghai 200090, P.R. China.
authors.forename: Lidong
authors.initials: L
authors.lastname: Shao
authors.affiliation: Department of Chemistry, Physical and Theoretical Chemistry Laboratory, Oxford University , South Parks Road, Oxford OX1 3QZ, United Kingdom.
authors.forename: Richard G
authors.initials: RG
authors.lastname: Compton