Theoretical study of H₂S adsorption and decomposition on CeO₂ (111) and defective CeO_2-x (111) surfaces

The adsorption and decomposition of H₂S on CeO₂ (111) surfaces were studied using the first-principles calculations based on the density functional theory and the pseudopotential method. The adsorbed S species on CeO₂ surfaces were classified as molecular H₂S, SH, and atomic S. The molecular H₂S was mostly associated with surface Ce sites. The adsorption of HS was more stable on O sites, and atomic S specie was bridged with Ce and O sites. The first dehydrogenation step of H₂S on CeO₂ (111) surface had a small barrier (0.16 ev), and the second step was 0.28 ev. The differences adsorption and decomposition of H₂S on CeO₂ (111) surface and defective CeO₂ (111) surface were compared. This is an abstract of a paper presented at the 231st ACS National Meeting (Atlanta, GA 3/26-30/2006).