Estimating the Electrochemically Active Area: Revisiting a Basic Concept in Electrochemistry

The well-known electrochemical probe Fe(CN)63-/Fe(CN)64- is widely used for estimating the electrochemically active area of electrodes modified with carbon nanotubes, conductive polymers, enzymes, etc. In this study, we platinum electrode, smooth or platinized different roughness factors, to demonstrate that such a redox couple fails respond surface variation. We determined factors Pt surfaces by atomic force microscopy (AFM) images, which yielded values between 2.72 and 25.91. Almost same were found using charge hydrogen monolayer desorption obtained from steady-state cyclic voltammetry experiments performed in an acid medium. They then compared those provided peak current chronoamperometry Fe(CN)6 3-/Fe(CN)64- all nearly one. Such comparison demonstrates behavior outer sphere reaction quite small interaction electrode surface, thus not being suitable be related areas.