Errors hydrodynamic electrodes

Often bubbles are generated at the electrode surface (e.g., when the reaction being studied is the hydrogen evolution reaction) or reach it from the bulk of the solution, from the gas used to deaerate it, or from degassing of the solvent. A bubble trapped at the surface of the RDE is driven toward its center by centrifugal force. This phenomenon can cause major errors in measurement because (a) part of the surface of the electrode is blocked and (b) the hydrodynamic flow in the vicinity of the electrode can be greatly distorted. 

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