The underpotential deposition of monolayer quantities of Ag and Cu has been studied using XPS and Auger spectroscopy. XPS chemical shifts of −0.65 and −0.95 eV vs. the bulk metal have been observed although no distinction was noted between the various underpotential states present in the cyclic voltammogram. The shifts were identical to vapor-deposited submonolayer films of Ag and Cu on Pt in the low coverage (θ ~ 0.1) limit. A gradual shift with coverage to the bulk metal value for the vapor-deposited films and a constant shift with coverage for the underpotential deposit indicated that islanding was present only in the evaporated films. Measurement of the Cu and Ag Auger spectra gave results independent of the surface work function when compared to the XPS spectra. Interpretation of this Auger parameter is, however, at present ambiguous.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Renewable Energy, Sustainability and the Environment
- Surfaces, Coatings and Films
- Materials Chemistry