Ex-situ and in-situ spectroscopic studies of the passive film on alkali and alkaline earth metals in nonaqueous solvents. Final report

Technical Report · Sun Mar 01 04:00:00 EST 1992

DOI:https://doi.org/10.2172/10180284· OSTI ID:10180284

Wang, K; Chottiner, G S; Herrera-Fierro, P; Scherson, D A ^[1]

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1. Case Western Reserve Univ., Cleveland, OH (United States). Dept. of Physics and Chemistry

The adsorption of carbon dioxide on potassium-dosed Ag(111) has been investigated with temperature-programmed desorption (TPD), work function measurements, and Auger electron (AES), X-ray photoelectron (XPS), and high resolution electron energy loss (HREELS), spectroscopies. Unlike the behavior observed for other K-modified single-crystal metal surfaces, the TPD spectra of near-saturation coverages of CO{sub 2} on K/Ag(111) for K coverages in the range 0.13 < {Theta}{sub K} < 0.47 exhibit a sharply defined m/e = 44 peak at 796 +/{minus} 6 K with no evidence for the desorption of CO at any temperature. Similar TPD experiments involving mixtures of natural and {sup 18}0-labelled CO{sub 2} indicate that the oxygen atoms undergo partial scrambling, suggesting that the overall process cannot be represented in terms of a simple adsorption/desorption of CO{sub 2}. The HREELS spectra of CO{sub 2}-saturated K/Ag(111) show, in addition to very minor features, a sharp peak at about 1480 cm{sup {minus}1}, and XPS spectra of the same interface display a C(ls) peak with a binding energy characteristic of an electron-rich carbon species. This information is consistent with the presence of a carbon-bound CO species on the surface. Evidence against the complete dissociation of CO{sub 2} was obtained from TPD which failed to reveal features associated with carbonate (decomposition) expected to be formed via the reaction of CO{sub 2} and adsorbed O. It is proposed that CO{sub 2} on K/Ag(111) binds through the carbon to the surface leading to the ``partial`` dissociation (or activation) of each CO{sub 2} molecule into adsorbed CO and O. Within this model, such adsorbed O would serve as a bridge between the carbon atoms of neighboring ``activated`` CO{sub 2} molecules, and therefore undergo exchange prior to or during thermal desorption.

• Research Organization: Lawrence Berkeley Lab., CA (United States); Case Western Reserve Univ., Cleveland, OH (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 10180284
• Report Number(s): LBL--32235; ON: DE93001529
• Country of Publication: United States
• Language: English

Related Subjects

25 ENERGY STORAGE
250901
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400102
400400
ADSORPTION
AUGER ELECTRON SPECTROSCOPY
CARBON DIOXIDE
CARBON MONOXIDE
CHEMICAL AND SPECTRAL PROCEDURES
CORROSION PROTECTION
DESIGN AND DEVELOPMENT
DOPED MATERIALS
ELECTROCHEMISTRY
ELECTRODES
METAL-GAS BATTERIES
POTASSIUM OXIDES
PROGRESS REPORT
SILVER OXIDES
SOLVENTS
SPECTROSCOPY
THIN FILMS