Cation Effects on the Potentials of Zero Charge of Gold, Silver, and Mercury Electrodes

Abstract

The potentials of zero charge of the mercury, silver, and gold electrodes were measured in aqueous salt solutions containing tetra‐alkylammonium and some other cations. The open‐circuit scrape method was used in the case of the solid electrodes, and the streaming electrode method was used for mercury. For mercury the potential of zero charge (pzc) shifts either positive or negative with increasing electrolyte concentration, depending on the relative adsorbabilities of the cation and anion. In the case of gold and silver the pzc is more cathodic in tetra‐alkylammonium or cesium salt solutions than in solutions containing sodium ions. This difference in trend for mercury from the gold or silver electrode, with cation variation, reflects the variance in metal‐anion vs. metal‐cation interactions on the different metals.