INITIAL-STAGES IN COPPER ELECTROCRYSTALLIZATION ON PLATINUM - THE IMPACT OF SULFURIC-ACID CONCENTRATION

The initial stages of copper electrocrystallization at polycrystalline platinum in 0.01 M CuSO4 solutions containing 0.5 M or 0.5 mM additiv es of H2SO4 are studied by chronoamperometry and cyclic voltammetry wi th a rotating ring-disk electrode. The sulfuric acid concentration is shown to affect the equilibrium potential of copper at the expense of complexing and changes in the nature of electroactive species. In weak ly acid electrolytes, adsorption of copper adatoms is enhanced, the st age of copper nuclei growth is accelerated, and the concentration of i ntermediate species is diminished in the course of the deposit dissolu tion as a result of changes in adsorption of anions and additional mig ration mass transfer.