EFFECTS OF ULTRASOUND ON THE ELECTRODEPOSITION OF LEAD DIOXIDE ON GLASSY-CARBON ELECTRODES

The electrodeposition of lead dioxide from lead(II) nitrate in an acid medium has been used as a test reaction to study the effects of an ul trasound held. The different behaviours found between platinum and gla ssy carbon electrodes have been compared by means of cyclic voltammetr y and simple potential steps. The current-time response for a platinum electrode is not affected by the presence or absence of ultrasound; i n contrast, significant changes have been observed in the characterist ic regions of these curves (induction time t(0)) with the glassy carbo n electrode. Scanning electron microscopy (SEM) has been employed to f ollow changes in the surface topography after the electrodes had been exposed to ultrasound. Results indicate that neither pits nor structur al modifications that may increase the electrode surface occur with th e device used. It is concluded that the activation of glassy carbon el ectrodes by the action of an ultrasound field for electrodeposition of lead dioxide is associated with the surface functionalization caused by the reaction of OH. radicals (derived from aqueous sonolysis) with the carbon surface.