Underpotential deposition of Cu on partially oxidized Rh electrodes

The underpotential deposition (UPD) of copper on partially oxidized rhodium electrodes was studied in acid medium using potentiodynamic techniques. The process was analyzed as a function of the potential and time of deposition. The potentiodynamic I-E patterns for the oxidative dissolution of Cu provide evidence for the existence of a chemical reaction between Cu and oxygen existing on the electrode surface. Redistribution of the active sites is also possible when appreciable quantities of oxidized species are simultaneously reduced by the UPD process. The partially oxidized rhodium electrodes were prepared by cyclic voltammetry and anodic polarization. The later method provided the most oxidized surfaces, but, even in this case, the degree of oxygen surface coverage was lower than that corresponding to a monolayer. Received: 11 July 1997 / Accepted: 10 February 1998