Photoemission Studies of H2S, H2 and S Adsorbed on Ru(110): Evidence for an Adsorbed SH Species.
NATIONAL BUREAU OF STANDARDS WASHINGTON DC SURFACE SCIENCE DIV
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H2S, H2 and S adsorbed on Ru110 have been studied by angle-integrated ultraviolet photoemission UPS as part of a study of the effect of adsorbed sulfur, a common catalytic poison, on this Ru surface. For low exposures of H2S at 80 K, the work function rises to a value 0.16 eV above that of clean Ru110 while the associated UPS spectra hnu 21.2 eV exhibit features similar to those of Hads and Sads and different from those of molecular H2S. We conclude that H2S dissociates completely at low coverages on Ru110 at 80 K. At intermediate exposures the work function drops and the UPS spectra show new features which are attributed to the presence of an adsorbed SH species. This appears to be the first direct observation of this surface complex. At higher exposures the work function saturates at a value 0.36 eV below the clean value the UPS spectra change markedly and indicate the adsorption of molecular H2S. Heating adsorbed H2S leaves a stable layer of Sads on Ru110. The surface with adsorbed sulfur strongly modifies the adsorption at 80 K of a number of molecules relative to the clean Ru110 surface. Author
- Atomic and Molecular Physics and Spectroscopy