Theoretical Study of Trimethylacetic Acid Adsorption on CeO2(111) Surface

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• 作者：Weina Wang ; S. Thevuthasan ; Wenliang Wang ; Ping Yang
• 刊名：Journal of Physical Chemistry C
• 出版年：2016
• 出版时间：February 11, 2016
• 年：2016
• 卷：120
• 期：5
• 页码：2655-2666
• 全文大小：686K
• ISSN：1932-7455

文摘

Trimethylacetic acid (TMAA) adsorption on stoichiometric and oxygen-deficient CeO₂(111) surfaces was investigated using density functional theory that accounts for the on-site Coulomb interaction via a Hubbard term (DFT+U) and long-range dispersion correction. Both the molecular state and dissociative state (TMAA → TMA^– + H⁺) were identified on stoichiometric and oxygen-deficient CeO₂(111) surfaces. For the stoichiometric surface, two thermodynamically favorable configurations with adsorption energies of the order of ?30 kcal/mol are identified; one is a molecule adsorption state, and the other one is a dissociative state. For the oxygen-deficient surface, dissociative states are more favorable than molecular states. The most favorable configuration is the dissociative adsorption of TMAA with the adsorption energy of the order of ?77 kcal/mol. The dissociated TMA moiety takes the position of oxygen vacancy, forming three Ce–O bonds. The signature vibrational frequencies for these thermodynamically stable structures are reported as well as their electronic structures. The effects of long-range dispersion interactions are found to be negligible for geometries but important for adsorption energies.