Attenuate-Total-Reflection Surface-enhanced Infrared Absorption Spectroscopy on Pt Nano-layers Electrodeposited on a Au/Si Substrate

Surface-enhanced infrared absorption spectra of CO have been obtained on Pt nano-layers properly electrodeposited onto a Au/Si substrate with the Kretschmann attenuate-total-reflection (ATR) configuration. The overall intensity in reflectance for the linearly adsorbed CO band is enhanced by a factor of around 10, compared to the corresponding theoretical maximum values for bulk metal surfaces with the external infrared reflection and absorption spectroscopy (IRAS). In comparison to the so-called abnormal infrared effects (AIREs) in the literature, the band intensity is comparable whereas the band direction is normal in the present study. Surface enhanced IR absorption effect of the above Pt nanolayer can be applied to characterize the intermediate species formed in methanol oxidation. The enhancement mechanism is briefly discussed based on surface plasmon oscillation excitable on the electrodeposited Pt surfaces.