Title: Digital simulation of the measured electrochemical response of reversible redox couples at microelectrode arrays: Consequences arising from closely spaced ultramicroelectrodes
Abstract: Diffusion to arrays of closely spaced (1.2-0.2 pm) ultramlcroelectrodes (50 pm X 2.3 w) was studied by dlgltal dmuiation and by examining the redox behavior of Ru(NH,)~+ in H,O. Cyiindrlcai diffusion of solution species resulted in quasi-steady-state currents at the microband electrodes. Generation-collectlon experlments, analogous to rotating ring-disk collection experhnents, resulted in larger generator currents than those observed at a single microelectrode due to the back diffusion of products to the neighboring mlcroe lectrode. A collection efficiency of 93% was observed for the reoxidation of RU(NH,):+ generated at a central microelectrode 0.2 pm from two fianklng collector mlcroelectrodes. This experlmenl as well as generator-shrgle collector electrode pairs was simulated at a two-dimensional rectangular expandlng grld and yielded results in good agreement wlth the experiment. Predictions of the model that the collection efflclency principally depends on the gap dze, rather than electrode wldth, were tested experimentally. The novel application of microelectrode arrays to the study of the foilow-up reactions of electrogenerated Intermediates is demonstrated. The digital simulation of electrochemistry of ultramicroelectrode arrays is shown here to be successful in predicting the effect of variations in electrode geometry on the current response. Our results on the properties of arrays of closely spaced microelectrodes represent the most complete study where theory can be tested with experiment.
Publication Year: 1986
Publication Date: 1986-08-01
Language: en
Type: article
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