Deposition of Cu onto polycrystalline Pt electrode from acidic CuSO4 solution in the presence of H2SeO3

The first stages of electrodeposition of Cu onto polycrystalline Pt in an acidic 0.1 M CuSO4 solution containing H2SeO3 were studied combining electrochemical and surface analytical techniques. The molar ratio of the concentrations of Cu2+ and H2SeO3 was from I x 10(5) to I x 10(3). The deposition kinetics was investigated by cyclic voltammetry and chronoamperometry; the elemental composition of deposits was studied by means of XPS, and the surface morphology by SEM. The instantaneous 3-D nucleation with diffusion-controlled growth model in the absence and in the presence of H2SeO3 was elucidated The XPS investigation revealed that the crystallites are comprised mainly of metallic copper and no more than 10 at. % elemental selenium. The number of nuclei per unit area calculated from the chronoamperometric data was of the order of I x 10(5) to I x 10(6) cm(-2) and that estimated from the SEM images was about two orders of magnitude larger.