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Difference between Ultramicroelectrodes and Microelectrodes: Influence of Natural Convection

2010; American Chemical Society; Volume: 82; Issue: 16 Linguagem: Inglês

10.1021/ac101210r

1520-6882

Christian Amatore, Cécile Pebay, Laurent Thouin, Ai‐Fang Wang, J-S. Warkocz,

Advanced battery technologies research

Natural convection in macroscopically immobile solutions may still alter electrochemical experiments performed with electrodes of micrometric dimensions. A model accounting for the influence of natural convection allowed delineating conditions under which it interferes with mass transport. Several electrochemical behaviors may be observed according to the time scale of the experiment, electrode dimensions, and intensity of natural convection. The range of parameters in which ultramicroelectrodes behave under a true diffusional steady state was identified. Mapping of concentration profiles was performed experimentally by scanning electrochemical microscopy in the vicinity of microelectrodes of various radii. The results validated remarkably the predictions of the model, evidencing in particular the alteration of the diffusional steady state by natural convection.