Specific adsorption of anions in the course of underpotential and bulk depositions and alloy formation of cadmium on a smooth gold support in acid medium

 The specific adsorption of ³⁶Cl-labelled Cl⁻ ions and ³⁵S-labelled HSO₄ ⁻ ions was studied in 1 mol dm⁻³ HClO₄ supporting electrolyte in the presence of Cd²⁺ ions at a gold support over a wide potential range corresponding to electrodeposition, alloy formation, underpotential deposition of Cd species and existence of an adatom-free surface. The distinct sections in the potential dependence of the adsorption of anions together with the potential versus time curves obtained under open circuit conditions reflect the changes in the state of the electrode surface, the dissolution of the bulk Cd phase and the slow elimination of Cd species from the Cd/Au alloy. Received: 16 March 1999 / Accepted: 5 May 1999