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C. Nishihara and H. Nozoye
[J. Electroanal. Chem., Vol.386, pp.75-82, 1995]
SThe detailed voltammetric behavior of the underpotential deposition (UPD) of copper in sulfuric acid solutions has been examined on a series of stepped surfaces of platinum single crystals: (955), (322), (15,11,11), (544), (10,9,9), (40,39,39) and (111). The comparison with the absorption/desorption voltammograms of hydrogen were carried out. The potentials of anodic peaks and cathodic peaks coincide for very low sweep rates of the electrode potential, e.g., 0.2 mV/s. However, on the wide terrace of (111) the anodic peak potential is about 10 mV positive of the cathodic peak potential at 0.05 mV/s. UPD of copper is a very slow proccess in sulfuric acid solution. It is shown that the most positive peak A may correspond to reduction/oxidation of copper on step sites.
Fig. 1. Cyclic voltammograms recorded on Pt(322), (544) and (41,39,39) electrodes in 0.5 M sulfuric acid solutions containing 0.2 mM Cu++ at 0.2 mV/s.