Exploring the Activated State of Cu/ZnO(0001)鈥揨n, a Model Catalyst for Methanol Synthesis

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• 作者：Erdni D. Batyrev ; N. Raveendran Shiju ; Gadi Rothenberg
• 刊名：The Journal of Physical Chemistry C
• 出版年：2012
• 出版时间：September 13, 2012
• 年：2012
• 卷：116
• 期：36
• 页码：19335-19341
• 全文大小：429K
• 年卷期：v.116,no.36(September 13, 2012)
• ISSN：1932-7455

文摘

The interaction of Cu clusters with ZnO(0001)鈥揨n terminated crystal faces is studied after reduction at high temperatures by a combination of scanning tunneling microscopy, scanning tunneling spectroscopy, X-ray photoelectron spectroscopy (XPS), and thermal desorption spectroscopy. We find that tiny amounts of Cu promote the reduction of the ZnO surface by means of triangular reconstruction. This metallization of the surface leads to a Cu鈥揨n alloy. The XPS results reveal that the degree of alloying depends strongly on the reduction temperature. This alloying stabilizes Zn from evaporation and H₂ desorption below 500 K. On the basis of these results, we conclude that the activated catalyst surface consists of Zn鈥揅u alloy sites that form at 700鈥?00 K. Moreover, the surface alloying enhances the activity of Cu/ZnO catalysts under typical methanol synthesis conditions.