Plasma treatment effect on Ag colloids was investigated using X-ray photoelectron spectroscopy (XPS) and surface-enhanced Raman scattering (SERS) techniques. XPS showed that O2 plasma was critical in removing organic contaminants on Ag colloids. With O2 plasma treatment, Ag colloids were oxidized to form flower-like Ag2O microclusters. The SERS spectral intensity of methyl orange (MO) adsorbed on Ag colloids became deteriorated with O2 plasma treatment. Followed by H2 plasma treatment, the SERS intensity of MO on Ag colloids regained, which indicated that Ag2O has been reduced to Ag. However, the reduction by H2 plasma could not bring Ag back to the original as-synthesized morphology. The flower-like microcluster morphology still remained. The formation mechanism of Ag2O microclusters is discussed.

XPS and SERS characterization of plasma-treated Ag colloids

251st National Meeting (2016)

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