Electrochemical behaviors of hierarchical copper nano-dendrites in alkaline media

In this study, hierarchical copper nano-dendrites (CuNDs) are fabricated via the electrodeposition method. The electrochemical behaviors of the as-obtained hierarchical CuNDs in 0.1 M NaOH aqueous solution are subsequently studied. The CuNDs experience a non-equilibrium oxidation process when subjected to cyclic voltammetry (CV) measurements. The first oxidation peak O1 in CV is attributed to the formation of an epitaxial Cu2O layer over the surface of the hierarchical CuNDs. However, the second oxidation peak O-2 in CV appears unusually broad across a wide potential range. In this region, the reaction process starts with the nucleation and growth of Cu(OH)(2) nanoneedles, followed by the oxidation of Cu2O. Upon the increase of potential, Cu2O is gradually transformed to CuO and Cu(OH)(2), forming a dual-layer structure with high productivity of Cu(OH)(2) nanoneedles.