NH3 Oxidation on Oxygen-Precovered Au(111): A Density Functional Theory Study on Selectivity

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• 作者：Nú ; ria L&oacute ; pez ; M&oacute ; nica Garcí ; a-Mota ; Jaime G&oacute ; mez-Dí ; az
• 刊名：Journal of Physical Chemistry C
• 出版年：2008
• 出版时间：January 10, 2008
• 年：2008
• 卷：112
• 期：1
• 页码：247 - 252
• 全文大小：545K
• 年卷期：v.112,no.1(January 10, 2008)
• ISSN：1932-7455

文摘

We have performed density functional theory simulations applied to slabs to study the dehydrogenation ofammonia on the surface of clean and atomic oxygen or hydroxyl precovered Au(111). Ammonia does notdissociate unimolecularly on the surface and needs a proton scavenger to drive decomposition. O atoms orhydroxyl groups on the surface are basic enough to attract the first H atom from the molecule and are alsoneeded in the resting dehydrogenation steps. Recombination steps to form N₂ and NO are hindered by barrierslower than those on Pt or Rh(111) due to the low interaction energies of molecular moieties with the Au(111)surface. The barrier for N₂ formation is in any case lower than that of NO in agreement with the high selectivityobserved toward N₂. Finally, coverage effects are discussed for the competing reactions.