Voltammetric study of electro-reduction of tetraamminepalladium(II) onto gold electrode

The work presents studies of the mechanism and kinetics of tetraamminepalladium(II) electro-reduction in ammonia - chloride solutions at pH = 9.5. The studies were preceded by the thermodynamic analysis of the electrolyte. The electrolyte stability was determined by UV-Vis absorbance measurements. Electrochemical examinations were performed by applying cyclic voltammetry (CV) combined with electrochemical quartz crystal microbalance (EQCM). The M/z values determined during electrogravimetric measurements indicate that reduction process of [Pd(NH3)(4)](2+) occurs in one step due to 2-electrons irreversible reduction reaction. Deposition of Pd takes place only in the overpotential deposition range. The examined reactions are diffusion controlled. Diffusion coefficient of [Pd(NH3)(4)](2+) participating in particular reactions was determined with the use of Berzins-Delahay equation. (C) 2012 Elsevier B.V. All rights reserved.