Electrochemical and in situ FTIRS studies of the CO adsorption at palladium and rhodium multilayers deposited on platinum single crystal surfaces .2. Pt(100) substrate

Multilayers of rhodium and palladium have been deposited on Pt(100) electrodes and subsequently characterized by means of cyclic voltammetry and charge displacement experiments. In addition, the saturated adlayer of CO on Pd/Pt(100) and Rh/Pt(100) has been studied by both electrochemical and infrared techniques. The voltammetric profile corresponding to these multilayers is due to a coupled adsorption/desorption process involving both anions and hydrogen. The set of different results seems to indicate that the multilayer is epitaxial in the case of palladium, thus behaving as a bulk Pd(100) electrode, whereas it is disordered in the case of rhodium. The spectra for the saturated CO adlayer on Rh/Pt(100) and Pd/Pt(100) also reflect the presence of the foreign metal deposit and give some indication about the bonding geometry and order of the CO adlayer. The CO saturation coverage for the Pd/Pt(100) system is around 0.63.