In Situ Imaging of Cu2O under Reducing Conditions: Formation of Metallic Fronts by Mass Transfer

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• 作者：Ashleigh E. Baber ; Fang Xu ; Filip Dvorak ; Kumudu Mudiyanselage ; Markus Soldemo ; Jonas Weissenrieder ; Sanjaya D. Senanayake ; Jerzy T. Sadowski ; Jos茅 A. Rodriguez ; Vladim铆r Matol铆n ; Michael G. White ; Dar铆o J. Stacchiola
• 刊名：Journal of the American Chemical Society
• 出版年：2013
• 出版时间：November 13, 2013
• 年：2013
• 卷：135
• 期：45
• 页码：16781-16784
• 全文大小：311K
• 年卷期：v.135,no.45(November 13, 2013)
• ISSN：1520-5126

文摘

Active catalytic sites have traditionally been analyzed based on static representations of surface structures and characterization of materials before or after reactions. We show here by a combination of in situ microscopy and spectroscopy techniques that, in the presence of reactants, an oxide catalyst鈥檚 chemical state and morphology are dynamically modified. The reduction of Cu₂O films is studied under ambient pressures (AP) of CO. The use of complementary techniques allows us to identify intermediate surface oxide phases and determine how reaction fronts propagate across the surface by massive mass transfer of Cu atoms released during the reduction of the oxide phase in the presence of CO. High resolution in situ imaging by AP scanning tunneling microscopy (AP-STM) shows that the reduction of the oxide films is initiated at defects both on step edges and the center of oxide terraces.