The ionic equilibrium in the CuSO4–H2SO4–H2O system and the formation of the honeycomb-like structure during copper electrodeposition

Abstract

The ionic equilibrium of the species in the CuSO4–H2SO4–H2O system was employed to systematize the conditions of copper electrodeposition leading to the formation of the honeycomb-like structure. The reason why CuSO4 concentrations higher than 0.15 M are unsuitable for the formation of honeycomb-like structures is shown. The range of H2SO4 concentrations enabling the formation of this type of structure was also determined. The conditions leading to the formation of the honeycomb-like structures are: electrodeposition from solutions with lower concentrations of Cu(II) ions (0.15 M CuSO4 and less) in a concentration range from 0.25 to 1.0 M H2SO4, at a temperature of 18.0±1.0 °C and at overpotentials outside the plateau of the limiting diffusion current density at which hydrogen evolution is vigorous enough to change the hydrodynamic conditions in the near-electrode layer.

Keywords

• electrolysis
• hydrodynamics
• morphology
• hydrogen
• copper