Nanometer-Sized Electrochemical Sensors
- 1 April 1997
- journal article
- research article
- Published by American Chemical Society (ACS) in Analytical Chemistry
- Vol. 69 (8), 1627-1634
- https://doi.org/10.1021/ac960887a
Abstract
Nanometer-sized glass-sealed metal ultramicroelectrodes (UMEs) have been prepared using a laser-based micropipet puller. The tip was exposed to solution either by etching away a small portion of glass insulator or by micropolishing. The characterization of the UMEs was carried out by a combination of steady-state voltammetry, scanning electron microscopy (SEM), and scanning electrochemical microscopy (SECM). The cyclic voltammograms obtained have a regular shape with very small capacitive and resistive background. The effective electrode radii obtained from voltammetry were between 2 and 500 nm. From the SEM micrographs, the shape of polished tips appears to be close to a microdisk, while the geometry of etched electrodes is closer to conical. Accordingly, the SECM current−distance curves (iT−d) obtained with polished electrodes fit well the theory for a disk-shaped tip, while a 20-nm-radius etched electrode was shown to be a fairly sharp cone with a height-to-radius ratio of about 2.5. The experimental data were compared to the theory developed for disk-shaped, conical, and recessed tips to demonstrate suitability of the produced electrodes for quantitative electrochemical experiments. The prospects of steady-state measurements of the rates of fast heterogeneous reactions are discussed. Submicrometer-sized ion selective electrodes (ISEs) were prepared by coating etched Ag tips with silver iodide. The concentration response of such ISEs remained stable and linear after coating of the ISEs with protective Nafion film.Keywords
This publication has 31 references indexed in Scilit:
- Voltammetric studies of carbon disk electrodes with submicrometer-sized structural diametersAnalytical Chemistry, 1995
- Fabrication and Evaluation of Nanoelectrode EnsemblesAnalytical Chemistry, 1995
- Microelectrodes: new dimensions in electrochemistryChemical Society Reviews, 1994
- The electrode/electrolyte interface - a status reportThe Journal of Physical Chemistry, 1993
- On possible systematic errors in determinations of charge transfer kinetics at very small electrodesJournal of Electroanalytical Chemistry and Interfacial Electrochemistry, 1991
- Fabrication and Use of Nanometer-Sized Electrodes in ElectrochemistryScience, 1990
- Construction of submicrometer voltammetric electrodesAnalytical Chemistry, 1990
- Steady-state voltammetryAnalytica Chimica Acta, 1989
- Comparison of voltammetric steady states at hemispherical and disc microelectrodesJournal of Electroanalytical Chemistry and Interfacial Electrochemistry, 1988
- Electrochemistry at platinum bane electrodes of width approaching molecular dimensions: breakdown of transport equations at very small electrodesThe Journal of Physical Chemistry, 1987