Electrochemical Study of Bulk and Monolayer Copper in Alkaline Solution

Abstract

The formation of copper oxides and hydroxides from metallic copper and underpotentially deposited copper atoms on platinum nanoparticles, when it is subjected to a potential scan between the hydrogen evolution potential and the oxygen evolution potential in alkaline solution as a function of scan rate and the pH of the solution has been investigated. Cyclic voltammetry of bulk copper electrodes in alkaline solution reveal that oxidation proceeds in steps leading to formation of Cu2O, Cu(OH)2 and CuO on the surface as well as some soluble oxides which corroborates well with X-ray photoelectron spectroscopy (XPS) analysis. Furthermore, interesting needle like formations on copper surface was observed in a scanning electron microscope (SEM), which can explain the unusual relation between the peak current and scan rate. On the other hand, the oxidation of copper monolayer on platinum nanoparticles leads primarily to formation of Cu2O and shows the effect of nobility imparted by the underlying platinum in terms of increased potential.