The electrochemical characterization of copper single-crystal electrodes in alkaline media

The use of single-crystals in electrochemistry requires careful characterization of the surface structure. This paper addresses the characterization of Cu single-crystals using blank cyclic voltammetry in alkaline media. The adsorption and desorption of OH species in the underpotential region of Cu2O formation in alkaline media occur at different potentials on Cu(1 1 1) and Cu(1 0 0), whereas OH adsorption on Cu(1 1 0) is not observed in this potential region. This allows for a direct distinction of the Cu(hkl) basal planes. The adsorption of OH on Cu(1 1 1) induces a reconstructed adlayer on the surface. On Cu(3 2 2), a stepped surface with 5 atom wide (1 1 1) terraces, OH adsorption is observed in the same potential range as on Cu(1 1 1), but on Cu(3 2 2) reconstruction does not seem to take place. This is explained by the fact that the unit cell of the reconstructed layer is much larger than the (1 1 1) terrace width of Cu(3 2 2) and, therefore, reconstruction cannot take place. Cu(9 1 1), having 5 atom wide (1 0 0) terraces, exhibits the same voltammetric features as Cu(1 0 0), but with a lower intensity. This is explained by the lower amount of (1 0 0) terraces present on this surface.