期刊
SURFACE SCIENCE
卷 618, 期 -, 页码 140-147出版社
ELSEVIER
DOI: 10.1016/j.susc.2013.09.001
关键词
Cerium dioxide; DFT plus U; CO oxidation; Oxygen vacancy; Electron localization; Reaction mechanism
资金
- National Basic Research Program [2010CB732300, 2011CB808505]
- National Natural Science Foundation of China [21073060]
- Shanghai Rising-Star Program [12QH1400700]
- National High Technology Research and Development Program of China [2012AA062703]
Density functional theory calculations corrected by on-site Coulomb interaction have been conducted to illuminate the effect of O vacancies on the surface reactivities toward direct CO oxidation at CeO2(110) and (111). CO adsorption at and further reaction with various surface O at the vacancy were systematically calculated, and extensive geometric and electronic analyses were also performed to understand the calculation results. It has been shown that though the existence of O vacancy can reduce the activities of neighboring O as the barriers of elementary steps are generally higher than those at stoichiometric surfaces, the relative preference for CO2 desorption is also increased due to the missing of nearby O for carbonate formation. Moreover, our calculation results also showed that the characteristic localized 4f orbitals/electrons of Ce still play the key role in determining the surface reactivities as the vacancy induced localized electrons can hinder their further occurrence and the corresponding reactions. (C) 2013 Elsevier B.V. All rights reserved.
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