Effect of the surrounding aeration on microcapillary electrochemical cell experiments

In the microelectrochemical capillary cell technique a silicone rubber gasket is used to avoid any electrolyte leakage between the pulled glass capillary and the working electrode (the metallic tested material). In this study, it is demonstrated that the oxygen reduction reaction (ORR) is strongly affected by the use of the silicone rubber. Experiments under a surrounding argon gas shielding of the pulled capillary in contact with the metallic surface have been performed showing a large effect on the ORR. Considering the high permeation rate of oxygen through silicone, the decrease of the reaction rate observed experimentally was validated by FEM modelling assuming that the air/silicone/water interface at the tip can be described as an air/water interface.