| Abstract
| - Mass transport to micrometer-sized electrodes in a microjet (wall-tube) electrode configuration is examinedexperimentally and through finite element modeling. Electrochemical imaging experiments reveal that localmass transport is highly sensitive to the lateral position of the nozzle with respect to the electrode. Whenthese two components are arranged coaxially, there is a pronounced minimum in the mass transfer rate to theelectrode, as determined from transport-limited current measurements. Small lateral displacements of thenozzle from the coaxial position lead first to an increase in mass transport, with the current reaching a maximumat a displacement of around one nozzle radius (50 μm). For larger lateral displacements of the nozzle fromthe coaxial position, the limiting current gradually decreases with increasing distance. The implications ofthese observations for practical applications of the microjet electrode are considered. Voltammetricmeasurements on the oxidation of IrCl63- in aqueous solution, with the electrode and nozzle coaxial areshown to be in good agreement with simulation of mass transport. Increasing the solution viscosity dramaticallydecreases mass transport to the electrode, with the reduction in the diffusion coefficient of the redox speciesas the major factor.
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