Effect of surface active cations undergoing interfacial rearrangements on deposition type electrode reactions

Abstract

The influence of the adsorption of methyltriphenyl- and cyclopropyltriphenylphosphonium cations on simple deposition reactions of Cd2+ and Zn2+ at the dropping mercury electrode, is studied by polarographic techniques. The size parameters of the activated complex, r≠, and adsorbate particles, ri, are determined and discussed. It is shown that for substances undergoing interfacial rearrangements, i.e. condensation and reorientation, the values of the size ratio r≠/ri can hardly be correlated to independently determined values of r≠ and ri. Electrode coverages are related to formal rate constants and an elucidation of the inhibition mechanism is attempted.