Electrodeposition of rhodium onto a pre-treated glassy carbon surface

The electrodeposition of rhodium from a 0.5 M NaCl + 5 mM Na3RhCl6 solution onto an electrochemically activated glassy carbon (GC) electrode was investigated by cyclic voltammetry and chronoamperometry. The cyclic voltammogram showed the presence of two cathodic peaks associated with the deposition of Rh. The analysis of the chronoamperometric curves, according to the existing theories, indicated that the Rh electrodeposition can be explained by a combination of several nucleation processes: two-dimensional (2D) progressive nucleation, which transforms to 2D instantaneous nucleation at more cathodic potentials, followed by three-dimensional (3D) nucleation with diffusion controlled growth. The nucleation kinetic parameters were determined according to these theories.