Adsorption and Redox Reactions of CO and O2 on RuO2(110) Surface: Quantum Mechanical Similation

• Main Authors: Chia-Ching Wang, 王嘉慶
• Other Authors: Jyh-Chiang Jiang
• Format: Others
• Language: en_US
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/6rf9k7

碩士 === 國立臺灣科技大學 === 化學工程系 === 94 === In this thesis, quantum mechanical calculation was employed to simulate the adsorption of CO and O2 on RuO2(110) surface. In addition, CO oxidation mechanisms on the surface also have been characterized by theoretical study. Two cluster models were applied in this work, one contains two adjacent Rucus site and another contains neighbored Rucus site and Rubr site. Reactions on RuO2(110) surface are successfully investigated by DFT calculation using the cluster models, the calculated binding energies and reaction energies are in good agreement with experiment. In the adsorption of CO and O2, the binding energies are strong affected by the bonding environment. There is a significant anti-cooperative effect: the binding energies will be reduced when the neighboring site is occupied by other species, especially when an oxygen atom on neighboring site. For O2 adsorption, the pathways of adsorption mechanism also been characterized. The adsorption energies of oxygen species are very high and RuO2(110) surface shows a good oxygen storage ability. Besides the oxygen species Ocus and Obr on RuO2(110) surface that have been investigated before, 1�� superoxo and bridge superoxo oxygen species were characterized in this work. 1�� superoxo oxygen species is an oxygen molecule adsorbed on Rucus site with one oxygen atom dangled, where the dangled oxygen atom demonstrates a high reaction activity. There are four CO oxidation mechanisms are proposed in this work. In CO oxidation reactions, adsorbed CO molecule reacts with dangled oxygen atom provides a reaction mechanism with lowest barrier of 0.55 eV, which is much lower than other mechanisms that are about 1 eV.