RAIRS Characterization of CO and O Coadsorption on Cu(111)

In a study preliminary to investigating CO2 dissociation, we report our results on oxygen and carbon monoxide coadsorption on Cu(111). We use reflection adsorption infrared spectroscopy and Auger electron spectroscopy to characterize and quantify adsorbed species. On dean Cu(111), the CO internal stretch mode appears initially at 2077 cm(-1) for a surface temperature of similar to 80 K. We accurately reproduce the previously determined redshift of the absorption band with increasing CO coverage. We subsequently oxidize the surface by exposure to O-2 at 300 K to ensure O-2 dissociation. The band's frequency and line shape of subsequently adsorbed CO at similar to 80 K are not affected. However, the maximum absorbance and integrated peak intensities drop with increasing O coverage. The data suggest that CO is not adsorbed near O, likely as a consequence of the mechanism of Cu(111) surface oxidation by O-2 at 300 K. We discuss whether our RAIRS results may be used to quantify CO2 dissociation in the zero-coverage limit.

Automated summary

This study investigates the coadsorption of oxygen and carbon monoxide on Cu(111) as a preliminary step to studying CO2 dissociation. The results show that the adsorption of oxygen affects the adsorption of CO, indicating the mechanism of surface oxidation. The findings provide valuable insights for understanding CO2 dissociation.