Metal electrodeposition onto diverse substrates continues to be a subject of significant interest more specifically for improved corrosion properties (coatings) and the production of integrated circuits. Among the metallic coatings used to protect steel surfaces, 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 causes 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 (GC) was investigated using cyclic voltammetry (CV) and potential step techniques in an aqueous solution 10 -2 M ZnCl 2 , in 1M NH 4 Cl. The experimental current density transients showed that the mechanism of zinc electrodeposition in 1M NH 4 Cl occurs by multiple, progressive three-dimensional nucleation with controlled by mass transfer.

The electrocatalytic behavior of nanocrystalline Co 30 Ni 70 , Co 40 Mo 60 , Ni 40 Mo 60 , Co 15 Ni 30 Mo 55 , Fe 10 Co 35 Ni 55 and Co 15 Fe 30 Ni 55 mol-% alloys on the oxygen evolution reaction [OER] in a 30 wt-% KOH aqueous solution at 298, 323 and 343 K has been assessed in this work. Appreciable currents for oxygen evolution reactions were measured at Ni-Co-Mo-Fe electrodes produce by this technique. It was also found that iron increased the electrocatalytic activity for oxygen evolution reaction, but it was not as good as obtained on hydrogen evolution reaction [HER]. Tafel plots of preoxidized and prolonged cycled Co 30 Ni 70 , Co 40 Mo 60 , Ni 40 Mo 60 , Co 15 Ni 30 Mo 55 , Fe 10 Co 35 Ni 55 and Co 15 Fe 30 Ni 55 crystalline electrodes were very different, which might be related to changes in the surface enrichment of one or two of the alloy constituents. The electrocatalytic effects Mo seem to be more important on the OER at high temperatures than those showed previously for HER. Nickel and Molybdenum rich alloys showed particularly high activity towards the OER in comparison with their nanocrystalline counterparts.