Potential of zero charge of monocrystalline copper electrodes in perchlorate solutions

The potentials of zero charge (pzc) of copper monocrystalline electrodes of three basal indices, namely (1 1 1), (1 1 0) and (1 0 0) and a polycrystalline electrode have been determined by impedance spectroscopy methods, in the frequency range of 1–100 Hz. Experiments were carried out in perchlorate solutions. The values of the pzc for (1 1 1), (1 0 0) and (1 1 0) were equal to −0.70, −0.73 and −0.75 V vs SHE electrode, respectively. This sequence of pzc is the same as for other monocrystalline electrodes of fcc structure, i.e. the pzc is most negative for the open (1 1 0) and less negative for the close packed (1 1 1) structures, though the differences are much smaller than reported by others. A dependence of the pzc on the pH of the solution was observed.