The Effect of the Cu 2+ /Cu+ Step on Copper Electrocrystallization in Acid Noncomplexing Electrolytes

This study investigates the effect of different electrolytes such as H20849ClO4−, NO3−, and SO42− at 1 M with a pH of 3 on the kinetics, growth type, and morphology of copper electrodeposition on glassy carbon. A systematic analysis was conducted using cyclic voltammetry to characterize the reduction peaks in various media. The findings revealed that nitrate ions resulted in a larger reduction peak compared to other electrolytes due to catalytic reduction processes on recently deposited copper. Despite the instability of Cu+ in these solutions, the Cu2+/Cu+ reduction step was classified as an electron-transfer reaction influenced by anion presence. Results indicated significant variations in the electrocrystallization process, particularly with sulfates causing a notable current decrease linked to the Cu2+/Cu+ step, while nitrate ions accelerated this reaction. Scanning electron microscopy provided visual confirmation of copper deposit morphology in accordance with electrochemical predictions. Overall, this research enhances understanding of the electrolyte influence on copper nucleation and growth dynamics in an acidic environment.