Infrared reflection absorption study of carbon monoxide adsorption on Fe-deposited Pt(111) surface

Abstract

Infrared reflection absorption spectroscopy (IRRAS) was used to investigate carbon monoxide (CO) adsorption on sub-monolayer (ML)-thick Fe deposited Pt(111). The CO exposure to a clean Pt(111) surface at room temperature yielded linear-bonded and bridge-bonded CO-Pt bands at 2090 and 1850 cm-1. The CO-Pt band intensities decreased steeply with increasing Fe thickness. For a 1-ML-thick-Fe/Pt surface, the bridge-bonded CO-Fe band at 1950 cm-1 dominated the spectra. Furthermore, the Fe depositions showed a new absorption band at around 2060 cm-1. The IRRAS spectrum for CO adsorption on the 3-Å-thick-Pt-covered a 1-ML-Fe/Pt(111) surface showed a single absorption at 2070 cm-1. Based on the IRRAS results, we discuss CO adsorption behavior on sub-ML-thick Fe/Pt(111) surfaces.