Computational Investigation of Fe–Cu Bimetallic Catalysts for CO2 Hydrogenation

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• 作者：Xiaowa Nie ; Haozhi Wang ; Michael J. Janik ; Xinwen Guo ; Chunshan Song
• 刊名：Journal of Physical Chemistry C
• 出版年：2016
• 出版时间：May 5, 2016
• 年：2016
• 卷：120
• 期：17
• 页码：9364-9373
• 全文大小：566K
• 年卷期：0
• ISSN：1932-7455

文摘

Density functional theory (DFT) calculations were carried out to investigate Fe–Cu bimetallic catalysts for the adsorption, activation, and initial hydrogenation of CO₂. CO₂ adsorption strength decreases monotonically as surface Cu coverage increases. For dissociation of CO₂, the reaction energy and activation barrier scale linearly with surface Cu coverage. The reaction energy becomes less exothermic, and the activation barrier increases with increasing surface Cu coverage from 0 to 1 ML. For initial hydrogenation of CO₂, formation of a formate (HCOO*) intermediate is kinetically favored over carboxyl (COOH*) at all surface Cu coverages. A substantial decrease of the kinetic barrier for HCOO* formation is observed when surface Cu coverage increases to 4/9 ML. CO* is the preferred intermediate from CO₂ dissociation at 2/9 ML surface Cu coverage or below; however, the favorable conversion path changes to CO₂ hydrogenation to a HCOO* intermediate when surface Cu coverage increases to 4/9 ML or higher. The composition and structure of the bimetallic catalysts determine the preferred intermediates and dominant reaction paths for CO₂ conversion, and thus, both impact the catalytic activity and selectivity.