Interaction between Monomeric Vanadium Oxide Clusters Supported on Titania and Its Influence on Their Reactivity

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• 作者：Henrik H. Kristoffersen ; Horia Metiu
• 刊名：Journal of Physical Chemistry C
• 出版年：2016
• 出版时间：June 30, 2016
• 年：2016
• 卷：120
• 期：25
• 页码：13610-13621
• 全文大小：594K
• 年卷期：0
• ISSN：1932-7455

文摘

Density functional theory is used to study monomeric vanadium oxide clusters formed by exposing to oxygen a rutile TiO₂(110) surface on which vanadium atoms have been preadsorbed. Past calculations examined such systems by using one V atom per supercell. This forces all VO_x clusters to be identical and precludes interactions between them. To examine the consequences of this choice, we examine a VO_x and a VO_y cluster in the same supercell. We find that the most stable configuration is obtained when the supercell contains one VO₂ and one VO₃ cluster. The stabilization occurs because of a Lewis acid–base interaction: VO₂ donates electron charge to VO₃ and this lowers the energy substantially. No such interactions were found when the supercell contained VO_x clusters with the same number of oxygen atoms. These finding demonstrate that in some cases it is essential to have two clusters in the supercell and that results obtained with one cluster in the supercell can be misleading. We have also studied the reactivity of the clusters with hydrogen, which is considered a descriptor of the ability of the cluster to catalyze the breaking of a C–H bond in an alkane.