Carbon Contamination at Silver Surfaces:  Surface Preparation Procedures Evaluated by Raman Spectroscopy and X-ray Photoelectron Spectroscopy

The quantity and chemical nature of carbonaceous impurities remaining on polycrystalline Ag surfaces after preparation depend on the protocol used for cleaning. The effectiveness of several preparation protocols was investigated in this study: mechanical polishing with successively finer grades of alumina, Ar+ sputtering, chemical polishing, and chemical polishing followed by Tl underpotential deposition. The impurities detected on polycrystalline Ag surfaces subjected to these preparation procedures are carbon, oxygen, and aluminum, and these are qualitatively and quantitatively identified with X-ray photoelectron spectroscopy. With Raman spectroscopy, these carbonaceous impurities are qualitatively identified as graphite, hydrocarbon, and cyanide species, the last of these being present only on the chemically polished surfaces.