The influence of high pressure (up to 10 kbar) on the limiting currents of the Cd(II)/Cd(Hg) system

Abstract The electroreduction of cadmium(II) at a mercury electrode and the oxidation of cadmium amalgam in 4.0 M NaCl at pressures ranging from 0.001 to 10 kbar, using cyclic voltammetry and chronoamperometry, revealed a moderate decrease in the limiting currents and diffusion coefficients of Cd II in solution and Cd in mercury. The partial molar volume of the diffusion activation calculated from these dependences is equal to 1.1–1.2 and 0.93 cm 3 mol −1 for diffusion in 4.0 M NaCl and in mercury, respectively. The formal potentials of the Cd II /Cd(Hg) system expressed versus the ferrocene-ferricinium ion electrode as a function of pressure led to a value of 10.7 cm 3 mol −1 for the volume of the electroreduction reaction of Cd II .