XPS INVESTIGATION OF LOW-TEMPERATURE ADSORPTION AND THERMAL-DESORPTION OF N2O ON AG(III)

The successive adsorption, condensation, desorption and dissociation steps of N2O on Ag (111) have been investigated using XPS as the main technique. The small Ols and Nls peak position shifts during N2O adsorption at low temperature (~30K) are interpreted as due to formation of a first N2O layer, with no strong interaction with the silver substrate, followed by multilayers built up at higher exposures. Almost complete desorption of the N2O multilayers occurs at about 100K. The remaining major surface species are O(a) characterized by a O1s peak at 528.2 eV and NO3(a) characterized by both a O1s peak at 531.4 eV and a N1s peak at 405.5 eV. Both species stay on the surface up to at least 426K, the upper temperature limit explored. In addition, there remains some O(a) subsurface species at 531.5 eV. Small amounts of NO(a) species are also detected between ~100 to ~250K. © 1990.