(766g) Characterization and Surface Chemical Reactions of Model Cu-ZnO/Silica Sorbents Upon H2S Adsorption and Regeneration

Zinc oxide sorbents have been considered to be favorable for H2S removal. The dopant Cu plays significant role in improving the performance of of ZnO sorbents.Well prepared model sorbents are necessary to study the changes in oxidation states,diffusion,thermal induced sintering, surface chemical reactions upon Sulfidation and regeneration.

Model sorbents have been prepared by RF-DC magnetron sputtering .Varying compositions of Cu-Zinc oxides are co-sputtered on to RCA cleaned Silicon wafers  using the Argon and oxygen as the inlet gases. Sulfided samples are prepared exsitu by passing H2S.Stuctural changes of the calcined vs sulfided sorbents are investigated by SEM-EDX and XRD,AFM. Oxidation states and atomic ratios are confirmed by XPS. Regeneration of “sulfided” sorbents was done in-situ by dosing oxygen and changes in the oxidation states determined. With the help of the temperature-dependent XPS changes in oxidation states of sulfur and the metal ions present in the sorbents, as well dynamics of ionic diffusion, depending on the temperature and oxygen partial pressure are explained. Also changes in the crystal structure due to annealing are studied with XRD