SONOELECTROCHEMISTRY IN HIGHLY RESISTIVE MEDIA - MASS-TRANSPORT EFFECTS

Sonovoltammetry methodology is studied for the enhancement of electroc hemical processes in highly resistive media. As model systems the redu ction of [FeCp(2)]PF6 (with Cp* = eta(5) -b C5Me5) and the oxidation of FeCp(2) in acetonitrile are examined at a 25 mu m diameter Pt micr odisk electrode. Both in the presence and in the absence of supporting electrolyte ultrasound induces a strong increase in the observed limi ting current in agreement with an increase in mass transport or. assoc iated with this, a change in the average diffusion layer thickness. Ho wever, iR drop effects cause distortion of voltammetric waves, potenti al fluctuation, and ultrasonically induced current decrease under cond itions of extremely low ionic strength.