High Coverage CO Activation Mechanisms on Fe(100) from Computations

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• 作者：Tao Wang ; Xinxin Tian ; Yong-Wang Li ; Jianguo Wang ; Matthias Beller ; Haijun Jiao
• 刊名：Journal of Physical Chemistry C
• 出版年：2014
• 出版时间：January 16, 2014
• 年：2014
• 卷：118
• 期：2
• 页码：1095-1101
• 全文大小：391K
• ISSN：1932-7455

文摘

CO activation on Fe(100) at different coverage was systematically computed on the basis of spin-polarized density functional theory. At the saturated coverage (11CO) on a p(3 脳 4) surface size (24 exposed Fe atoms), top (1CO), bridge (3CO) and 4-fold hollow (7CO) adsorption configurations coexist. The stepwise adsorption energies and dissociation barriers at different coverage reveal equilibriums between desorption and dissociation of adsorbed CO molecules. It is found that only molecular adsorption is likely for n_CO = 8鈥?1, and mixed molecular and dissociative adsorption becomes possible for n_CO = 5鈥?, while only dissociative adsorption is favorable for n_CO = 1鈥?. The computed CO adsorption configurations and stretching frequencies as well as desorption temperatures from ab initio thermodynamic analysis agree well with the available experimental data.