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 O₂ 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.