ac060924q_si_001.pdf (133.93 kB)
Kinetics of Electron-Transfer Reactions at Nanoelectrodes
journal contribution
posted on 2006-09-15, 00:00 authored by Peng Sun, Michael V. MirkinThe kinetics of several fast heterogeneous electron-transfer reactions were investigated by steady-state voltammetry at nanoelectrodes and scanning electrochemical
microscopy (SECM). The disk-type, polished Pt nanoelectrodes (3.7−400-nm radius) were characterized by
a combination of voltammetry, scanning electron microscopy, and SECM. A number of experimental curves were
obtained at the same nanoelectrode to attain the accuracy
and reproducibility similar to those reported previously
for micrometer-sized probes. A new analytical approximation was developed and used for analysis of steady-state
tip voltammograms. The self-consistent kinetic parameter
values with the uncertainty margin of ∼10% were obtained
for electrodes of different radii and for a wide range of
the SECM tip/substrate separation distances. The determined standard rate constants are compared to those
previously measured at the electrodes of different dimensions, and the correlation between the heterogeneous and
self-exchange rate constants is discussed.