Electrochemical Nucleation of Zinc onto Glassy Carbon

Abstract

Metal electrodeposition onto diverse substrates continues to be a subject of significant interest for improved corrosion properties (coatings) and the production of integrated circuits. Among the metallic coatings used to protect steel surface, electrodeposited zinc and zinc alloys are important in both decorative and industrial applications. Unfortunately, in the common electrolytic baths (sulfates, acetates, chlorides), Zn electrodeposition is accompanied by the hydrogen evolution reaction (HER), which cause a competition between both processes. Therefore, in such circumstances, a quantitative evaluation of the kinetic parameters of the zinc electrocrystallization process is almost impossible. In this work, Zn electrodeposition was analyzed using a non- conventional support electrolyte as alternative method to separate the involved processes. Zn electrodeposition onto glassy carbon (GCE) was investigated using cyclic voltammetry (CV) and potential step technique in an aqueous solution 10-2 M ZnCl2, in 1M NH4Cl. The experimental current density transients showed that the mechanism of zinc electrodeposition in 1M NH4Cl occurs by multiple, progressive three-dimensional nucleation with controlled by mass transfer.