Linear sweep voltammetry, cyclic voltammetry and chronoamperometry techniques were employed to study the copper electrocrystallization process on a glass carbon electrode (GCE) from acid cupric sulfate electrolytes in the presence of polyethylene glycol and Cl^－ ions. The instantaneous nucleation followed by three-dimensional growth was found for the electrocrystallization from the electrolytes with PEG-Cl^－. The electrochemical active sites on the GCE surface decrease in the presence of PEG-Cl^－ in electrolytes, which inhibited the electrodeposition and electrocrystallization of copper sharply. However, Cl^－ ions had a strong accelerant effect. With the increase of Cl^－ ion concentration, the diffusion coefficient of Cu^2＋, and the rate of copper electrodeposition and nucleation were promoted. An optimum chloride ion and PEG concentration increased the nuclear density on the GCE surface, which was beneficial to electrodeposits.

Key words: Cu, PEG-Cl^－, electrodeposition, electrocrystallization, GCE