Theoretical Study of the Oxygen Reduction Reaction on RuSe2(100) Surface
| Autor: | Li-wei Kao, 高立偉 |
|---|---|
| Rok vydání: | 2010 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 98 The plane-wave periodic density functional theory (DFT) calculations were employed to investigate (i) the surface energies of the various terminations of the (100) and (210) surfaces of RuSe2 and (ii) oxygen reduction reaction (ORR) reaction on the RuSe2(100) surface. The surface energy calculation demonstrates that RuSe2(100) surface with Se single layer termination exhibits the lowest surface energy. Therefore, the study of ORR mechanism was focused on the RuSe2(100) surface. Adsorption energies, geometric structures, and reversible potentials for elementary reaction steps on RuSe2(100) surface with six-atomic layer slab model were calculated. Our results showed that proton transfer via the heterogeneous pathway is more favorable than the homogeneous pathway. We considered two different heterogeneous pathways, the OOH formation route and the O2 dissociation route. The results show that the OOH formation route, four-electron pathway, is more favorable. The calculated onset potential (0.68 V) is comparable to that of Pt cathode catalysts, around 0.7~0.8 V. However, there still exists a small deviation. We conjecture that the deviation of the calculated reversible potential with the experimental result (about 0.85~0.9 volt) [37] could be resulted from from (i) the calculations were performed in a vacuum condition without solvent effect; (ii) the ( PΔV – TΔS ) term for gas phase reaction and surface reaction are assumed the same, but it may exists uneglectable change of the ΔS term. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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