A spectroelectrochemical technique is herein described in which the surface of a rotating disk electrode is used as a mirror to reflect a focused beam of Hght in the UV-vis range at a near normal incidence angle. This approach makes it possible to probe quantitatively the presence of absorbing species in the diffusion boundary layer under well-defined hydrodynamic conditions. Good agreement between theory and experiments was obtained using the oxidation of Fe(CN)6 4-as a model system. In particular, the absorbance difference at the diffusion limiting current was found to be proportional to the reactant concentration, cR, for a fixed rotation rate, ω, and proportional to ω-1/2for a fixed cR.
ASJC Scopus subject areas