AN ELECTRON-ENERGY LOSS STUDY OF CARBON-DIOXIDE ADSORPTION ON ALKALI-METAL PREDOSED SILVER SURFACES

The interactions between carbon dioxide (CO2) and alkali metals on rough silver surfaces have been studied with electron energy loss spectroscopy (EELS). In the absence of alkali metal, CO2 is found to bind weakly to the silver surface. With either lithium, potassium or cesium present, a surface complex of the form M+ CO- 2 is formed, in agreement with a past Surface Enhanced Raman Scattering (SERS) investigation [J. Chem. Phys. 90 (1989) 6668] of the same systems. At sufficiently high CO2 exposures, CO2 adsorption also occurs. EELS and SERS spectra obtained from the same alkali-predosed silver surface, are often found to be dominated by different species leading to the conclusion that each of the two spectroscopies probes different regions of the rough surface with differing sensitivities. © 1990.