Characterization and Electrochemical Investigation of Heterogeneous Sb-Cu Coatings

Abstract

In recent years, Cu-Sb-based alloys have been considered promising materials for various green applications; for instance, they can serve as catalysts for CO2 reduction, anodic material for metal-ion batteries, and a light-absorbing layer in solar cell. Our research is focused on the electrodeposition of antimony-copper alloy layers with copper content between 18–30 wt.%. The layers were observed by scanning, atomic force and transmission electron spectroscopies. Their phase structure, roughness, and hardness were also determined. The electrochemical properties were investigated by using electrochemical impedance spectroscopy and potentiodynamic polarization tests in 0.5 M sulfuric acid. Decreasing the copper content leads to an increase in chemical and morphological heterogeneity and an increase in the roughness from 1.74 to 2.94 μm due to the separation of antimony crystal clusters protruding above the surface but does not significantly affect the hardness and electrochemical behavior of the layers. Copper is recorded only in the form of the Cu2Sb phase. The corrosion current density and potentials of the layers are close to those of pure antimony (about 20 µA cm−2 and about −30 mV vs. Ag/AgCl). The highly porous structure obtained after anodic polarization seems suitable for catalytic purposes.