The influence of iodide adsorption on copper underpotential deposition on polycrystalline palladium electrodes in mildly acidic solutions

The effects of I- adsorption on the electrodeposition (under and overpotent ial deposition) of Cu on polycrystalline Pd electrodes were studied in dilu te perchloric acid solutions at 18 degrees C. It had been found that Cu und erpotential deposition on polycrystalline Pd exhibits different potentiodyn amic features, which are characteristic of defined crystallographic planes of Pd. However, these features varied when the voltammograms were performed in the presence of strongly adsorbable anions, such as I-. In spite of hav ing found a partial inhibition of the Cu voltammetric features in the prese nce of I-, we calculated integer numbers in the electron transfer to Cu2+ a nd I- ions. The change in the values of Cu massive deposition potential due to the presence of I- was caused by the appearence of a new electrode, tha t is, the Cu/CuI/I- interface. (C) 1999 Academic Press.