Effect of H2SeO3 on the early stages of nucleation and growth during Cu electrocrystallization in acidic medium on glassy carbon electrode

Abstract

The early stages of Cu electrodeposition onto a GC electrode were investigated in 0.5 M H2SO4 + 0.01 M CuSO4 solution without or with H2SeO3 when a molar concentration ratio [Cu(II)]/[Se(IV)] was 1.104 to 2.102. The H2SeO3 solution in 0.5 M H2SO4 was also used. The electrochemical techniques such as cyclic voltammetry and chronoamperometry and structural investigation using ex situ AFM were applied to study the nucleation and growth of Cu onto a GC electrode. Chronoamperometric results were shown to follow an instantaneous 3D nucleation and diffusion-controlled growth model by Scharifker and Hills. The values of number of Cu nuclei N and average nuclei radius r av were calculated. It was shown that, in the presence of H2SeO3 in amounts of 0.001 to 0.005 mM, N increases and r av decreases. At higher concentrations of the additive, the changes of these parameters with the deposition potential E dep were shown to be somewhat more complex. The dependences of N and r av on the concentration of H2SeO3 in different regions of Cu overpotentials were also revealed.