Study on the Adsorption and Reactions of FCH2CH2OH and ClCH2CH2OH on Ni(111): Effects of Halogen and Preadsorbed Oxygen

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• 作者：Jong-Liang Lin ; Shu-Jui Tsao ; Chih-Wei Chen ; Yi-Shiue Lin ; Tz-Shiuan Wu ; Sian-Cong Chen ; Szu-Hui Li
• 刊名：Journal of Physical Chemistry C
• 出版年：2013
• 出版时间：December 5, 2013
• 年：2013
• 卷：117
• 期：48
• 页码：25488-25496
• 全文大小：535K
• 年卷期：v.117,no.48(December 5, 2013)
• ISSN：1932-7455

文摘

Temperature-programmed reaction/desorption (TPR/D), reflection鈥揳bsorption infrared spectroscopy (RAIRS), and X-ray photoelectron spectroscopy (XPS) have been employed to investigate the reactions of FCH₂CH₂OH and ClCH₂CH₂OH on Ni(111) and oxygen-precovered Ni(111) (O/Ni(111)). In the chemical process of FCH₂CH₂OH on Ni(111), only FCH₂CH₂O- is found to be the stable reaction intermediate, which starts to appear at 190 K. At low coverages, this intermediate decomposes into H₂ and CO. Additional C₂H₄ (219 K) is generated at higher exposures. On Ni(111) at 200 K, ClCH₂CH₂OH mainly dissociates to form ClCH₂CH₂O- and -CH₂CH₂O- at lower exposures, with H₂ and CO as the final products, while ClCH₂CH₂O- becomes predominant at higher exposures and is responsible for the extra C₂H₄ channel of 218 K. C₂H₄ is also generated at 161 and 174 K as the exposure is increased to render multilayer adsorption. Due to the competition in the scission of the carbon鈥揾alogen and carbon鈥揾ydrogen bonds, ClCH₂CH₂OH has better reactivity toward C₂H₄ formation than FCH₂CH₂OH. No -CH₂CH₂OH is found in the decomposition of FCH₂CH₂OH and ClCH₂CH₂OH on Ni(111), which is the intermediate in the reaction of ICH₂CH₂OH on Ni(100) and Pd(111). The presence of preadsorbed oxygen can enhance the ethylene formation at low coverages of FCH₂CH₂OH and ClCH₂CH₂OH. At higher coverages, additional acetaldehyde is formed in the reaction of FCH₂CH₂OH, in contrast to the ethylene oxide from ClCH₂CH₂OH.