Na2SO4-assisted shift in the nucleation mechanism of copper-electrocrystallization from an acidic bath

[Display omitted] •Copper electrodeposition on graphite from acidic sodium sulphate (Na2SO4) solution.•Copper films were fine grained with Na2SO4 present compared to when it was absent.•Films formed in the presence of Na2SO4 were comparatively smoother.•Na2SO4 changed the deposition mechanism from charge to mass transfer controlled. In this study, the effect of sodium sulphate (Na2SO4) on the nucleation mechanism of copper films during electrodeposition was investigated. Voltammetric and chronoamperometric studies were employed to analyze the kinetics of electrochemical nucleation. Phase analysis of the nucleated copper was performed via X-ray diffraction, while morphological and topographical studies were conducted using scanning electron microscopy (SEM) and atomic force microscopy (AFM) to further validate the electrochemical findings. The deposits obtained in the presence of Na2SO4 were finer and more closely packed compared to those formed without Na2SO4. Additionally, the roughness of the deposits varied between the two conditions, with films formed in the presence of Na2SO4 being slightly smoother. The results indicate that the addition of Na2SO4 changed the nucleation mechanism from charge transfer controlled to mass transfer controlled.