Difference between ultramicroelectrodes and microelectrodes: influence of natural convection.
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.
Amatore
Christian
C
Ecole Normale Supérieure, Département de Chimie, UMR CNRS-ENS-UPMC 8640 Pasteur, 24 rue Lhomond, F-75231 Paris Cedex 05, France. christian.amatore@ens.fr
Pebay
Cécile
C
Thouin
Laurent
L
Wang
Aifang
A
Warkocz
J-S
JS