SURFACE PARAMETERS EVALUATION FOR POLYCRY STALLINE AU ELECTRODES BY UNDERPOTENTIAL DEPOSITION OF CU

The underpotential deposition (UPD) of Cu on polycrystalline Au electr odes as well as their use for surface characterization were studied in this work. The real surface area and the roughness factor parameters were calculated from the charge involved at the potential plateau of t he electrochemical isotherm, Q(Cu) vs. E(d). The estimation of the fra ctional oxygen coverage, theta0, as well as the mean thickness of the Au2O3 layer, d(Au2O3), were carried out by means of the roughness fact or, f(Au), used here as a reference parameter. The corresponding value s obtained, 0.9 and 3.5 angstrom respectively, are in good agreement w ith those expected for an oxygen monolayer. From these results, the Cu UPD is proposed as an evaluation method of surface parameter of metal lic electrodes for which a well defined primary inner reference is lac king.