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)(4)(2-). For thinner platinum overlayers, changes in the spectra due to migration of CN- from Ag(CN); 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)(4)(2-). (C) 1999 Elsevier Science B.V. All rights reserved.