First-principles study of H2S adsorption and dissociation on Mo(1 1 0)
| Autor: | Haijun Luo, Ming-Qiu Tan, Jian-Qiu Cai, Xiang-Ming Tao |
|---|---|
| Rok vydání: | 2015 |
| Předmět: |
General Computer Science
Chemistry General Physics and Astronomy chemistry.chemical_element General Chemistry Potential energy Sulfur Dissociative adsorption Dissociation (chemistry) Computational Mathematics Crystallography Adsorption Mechanics of Materials Physical chemistry General Materials Science Dehydrogenation Density functional theory |
| Zdroj: | Computational Materials Science. 101:47-55 |
| ISSN: | 0927-0256 |
| DOI: | 10.1016/j.commatsci.2015.01.003 |
| Popis: | The dissociative adsorption of H2S on perfect and S-covered Mo(1 1 0) surfaces have been studied using density functional theory. Adsorption mechanisms of H2S, SH, S and H on both surfaces were analyzed and all possible potential energy profiles of H2S dissociation processes were mapped out. It indicated that H2S, SH, S, and H energetically favor the short bridge, long bridge, hollow, and hollow sites, respectively, on perfect surface, and favor the top, long bridge, hollow, and hollow sites, respectively, on S-covered surface. The first H2S dehydrogenation on clean surface has a barrier of 0.18–0.31 eV, while it required a high energy barrier of 0.40–0.88 eV on S-covered surface. The second dehydrogenation showed a lower barrier of 85 meV on perfect surface, but a higher barrier of 0.29 eV on S-covered surface. All these findings indicated that H2S can easily decompose on perfect Mo(1 1 0) surface, but the presence of atomic sulfur went against the H–S bond-breaking process both thermodynamically and kinetically. Finally, densities of electronics states and vibrational frequencies have been used to characterize the interactions between adsorbed species and the substrate. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect