A Photoemission Study of Ethylene Decomposition on a Co(0001) Surface: Formation of Different Types of Carbon Species

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• 作者：Lingshun Xu ; Yunsheng Ma ; Zongfang Wu ; Bohao Chen ; Qing Yuan ; Weixin Huang
• 刊名：The Journal of Physical Chemistry C
• 出版年：2012
• 出版时间：February 16, 2012
• 年：2012
• 卷：116
• 期：6
• 页码：4167-4174
• 全文大小：450K
• 年卷期：v.116,no.6(February 16, 2012)
• ISSN：1932-7455

文摘

We have studied the interaction of ethylene on Co(0001) in detail by X-ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS). At 130 K, the chemisorption and decomposition of C₂H₄ were found to depend on the vacant sites available on Co(0001). C₂H₄ chemisorbs dissociatively at low exposures but both dissociatively and molecularly at large exposures. Upon heating, some C₂H₄(a) desorbs molecularly from the surface, releasing vacant surface sites that result in the simultaneous decomposition of other C₂H₄(a). C₂H₂(a) is the surface intermediate for the decomposition of C₂H₄(a) on Co(0001). At elevated temperatures, C₂H₂(a) simultaneously undergoes the direct dehydrogenation and the cyclopolymerization鈥揹ehydrogenation to form surface C₂ cluster and graphitic carbon on Co(0001). At 500 K, C₂H₄ directly decomposes on Co(0001), forming surface atomic carbon. These results provide novel information on the chemisorption and decomposition of C₂H₄ on Co(0001) and the nature of resulted carbon species, greatly deepening our fundamental understanding of the relevant heterogeneous catalytic reactions catalyzed by Co-based catalysts and the growth of graphene on Co surfaces by chemical vapor deposition.