Active Surface Oxygen for Catalytic CO Oxidation on Pd(100) Proceeding under Near Ambient Pressure Conditions

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• 作者：Ryo Toyoshima ; Masaaki Yoshida ; Yuji Monya ; Kazuma Suzuki ; Bongjin Simon Mun ; Kenta Amemiya ; Kazuhiko Mase ; Hiroshi Kondoh
• 刊名：The Journal of Physical Chemistry Letters
• 出版年：2012
• 出版时间：November 1, 2012
• 年：2012
• 卷：3
• 期：21
• 页码：3182-3187
• 全文大小：355K
• 年卷期：v.3,no.21(November 1, 2012)
• ISSN：1948-7185

文摘

Catalytic CO oxidation reaction on a Pd(100) single-crystal surface under several hundred mTorr pressure conditions has been studied by ambient pressure X-ray photoelectron spectroscopy and mass spectroscopy. In-situ observation of the reaction reveals that two reaction pathways switch over alternatively depending on the surface temperature. At lower temperatures, the Pd(100) surface is covered by CO molecules and the CO₂ formation rate is low, indicating CO poisoning. At higher temperatures above 190 掳C, an O鈥揚d鈥揙 trilayer surface oxide phase is formed on the surface and the CO₂ formation rate drastically increases. It is likely that the enhanced rate of CO₂ formation is associated with an active oxygen species that is located at the surface of the trilayer oxide.

Keywords:

CO oxidation; Pd(100); surface oxide; ambient pressure XPS; mass spectroscopy; synchrotron radiation