The catalytic role of water in CO oxidation on Ag(111) surface：A Density Functional Theory Study
| Autor: | Chang, Ming-Wen, 張銘文 |
|---|---|
| Rok vydání: | 2011 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 99 The role of water in CO oxidation on Ag(111) surface is studied by using density functional theory calculation. In the early stage of the reaction, water is found to prefer to co-adsorb with oxygen molecule. The coadsorption energy of water with oxygen molecule is lower than those of CO with water and CO with oxygen molecule. Our calculations find that the water molecule plays not only the role of stabilizing the CO and oxygen molecule but also as a proton donor of transferring a proton to an oxygen molecule, forming HO2 and OH with an activation energy of 0.09 eV. The formed HO2 is a stable intermediate with an adsorption energy of -1.13eV on Ag(111) surface. The dissociation of HO2 to form H + O2 or HO + O is hindered at low temperature. A highly active reaction pathway for CO oxidation via HO2*+ CO*→HO*+CO2 is found. Because this reaction barrier is only 0.05eV, it should be more facile than the oxidation reaction via a four-center O2…CO complex. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
| Externí odkaz: |
|