Adsorption and Surface Reaction of NO2 on a Stepped Au(997) Surface: Enhanced Reactivity of Low-Coordinated Au Atoms

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• 作者：Zongfang Wu ; Yunsheng Ma ; Yulin Zhang ; Lingshun Xu ; Bohao Chen ; Qing Yuan ; Weixin Huang
• 刊名：The Journal of Physical Chemistry C
• 出版年：2012
• 出版时间：February 9, 2012
• 年：2012
• 卷：116
• 期：5
• 页码：3608-3617
• 全文大小：645K
• 年卷期：v.116,no.5(February 9, 2012)
• ISSN：1932-7455

文摘

The adsorption and surface reaction of NO₂ on a stepped Au(997) surface were investigated by temperature-programmed desorption, X-ray photoelectron spectroscopy, and ultraviolet photoelectron spectroscopy. At low NO₂ exposures, NO₂ chemisorbs molecularly and reversibly on the Au(997) surface at 130 K, but low-coordinated Au atoms on the (111) step sites exhibit enhanced reactivity. NO₂(a) chemisorbed on the (111) step sites is thermally more stable than that chemisorbed on the (111) terrace sites. At large NO₂ exposures, an amorphous physisorbed N₂O₄ multilayer forms at 130 K. Subsequent heating causes the isomerization of the physisorbed N₂O₄ multilayer (O₂N鈥揘O₂) to nitrite鈥揘₂O₄ (ONO鈥揘O₂) and the subsequent transformation of nitrite鈥揘₂O₄ into nitrosonium nitrate (NO⁺NO₃^{鈥?/sup>) that further decomposes into NO(g) and NO₂(g) at elevated temperatures, forming O(a) on the surface. These surface reactions could be utilized to prepare oxygen adatoms on inert Au surfaces under ultrahigh vacuum conditions. Our results broaden the fundamental understanding of the interaction between small molecules and Au surfaces.}