Investigation of cyanide ions adsorbed on platinum and palladium coated silver island films by surface-enhanced Raman spectroscopy

Bimetallic films prepared by vacuum-depositing platinum onto silver island films have been evaluated for surface-enhanced Raman scattering (SERS), using CN− as the adsorbate. For platinum overlayers with mean thickness corresponding to 1–2 monolayers the spectrum is dominated by a band consistent with either CN− adsorbed at the platinum surface or with Pt(CN)42−. For thinner platinum overlayers, changes in the spectra due to migration of CN− from Ag(CN)2− to the surface platinum atoms were observed during the first few minutes of laser illumination. Similar palladium-on-silver films showed a prominent SERS band assigned to surface Pd(CN)42−.