INITIAL-STAGES IN COPPER ELECTROCRYSTALLIZATION ON PLATINUM - THE IMPACT OF THE UNIVALENT COPPER IONS AT LOW OVERVOLTAGES

The initial stages in copper electrocrystallization at polycrystalline platinum in the 0.5 M H2SO4 + 0.01 M CuSO4 solution are studied at lo w overvoltages by chronoamperometry and cyclic voltammetry with a rota ting ring-disk electrode. The concentration of univalent copper is sho wn to drastically increase in the vicinity of the equilibrium potentia l in the near-electrode region, which creates conditions for depositin g more than a single layer of copper adatoms and forming a microdeposi t with specific characteristics. The microdeposit particles can act as active centers of three-dimensional nucleation at higher cathodic ove rvoltages.