| AVS 64th International Symposium & Exhibition | |
| Surface Science Division | Tuesday Sessions |
| Session SS-TuP |
| Session: | Surface Science Poster Session |
| Presenter: | Joel Langford, University of California Irvine |
| Authors: | J.M. Langford, University of California Irvine A.D. Babore, University of California Irvine J.C. Hemminger, University of California Irvine |
| Correspondent: | Click to Email |
High resolution electron energy loss spectroscopy, Auger electron spectroscopy, and temperature-programmed desorption has been used to study hydrogen sulfide adsorbed on two systems; metallic W (100) and oxygen adsorbed W (100). At exposure temperatures of 150 K hydrogen sulfide dissociates on both systems. However, for metallic W (100) and oxygen adsorbed W (100) the dissociation products are different. On metallic W (100) hydrogen sulfide dissociates to form W-SH and W-H. On oxygen adsorbed W (100) hydrogen sulfide dissociates to produce a combination of W-SH, W-OH, and W-H. These species were confirmed with both D2O and D2S experiments. When metallic W (100) is annealed SH groups recombine to desorb as molecular hydrogen leaving behind the W-S species. Therefore, adsorption of hydrogen sulfide on W (100) is irreversible. Both the vibrational spectroscopy and thermal desorption lack evidence of molecularly adsorbed H2S. The desorption peak for molecular H2S is therefore below the 150 K exposure temperature. On oxygen adsorbed W (100) both water and hydrogen desorption is observed. The intensity ratio of W-OH to W-SH vibrational modes and the water to hydrogen desorption ratio as a function of surface oxygen to tungsten was measured. Both the intensity ratio of W-OH to W-SH vibrational modes and water to hydrogen desorption peak is proportional to the oxygen concentration. A descriptive interpretation of hydrogen sulfide W (100) chemistry will be provided in this talk