Stoichiometric Zirconium Oxide Cations as Potential Building Blocks for Cluster Assembled Catalysts

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• 作者：Grant E. Johnson ; Roland Mitrić ; Eric C. Tyo ; Vlasta Bonač ; ić ; -Koutecký ; A. W. Castleman
• 刊名：Journal of the American Chemical Society
• 出版年：2008
• 出版时间：October 22, 2008
• 年：2008
• 卷：130
• 期：42
• 页码：13912-13920
• 全文大小：459K
• 年卷期：v.130,no.42(October 22, 2008)
• ISSN：1520-5126

文摘

Employing guided-ion-beam mass spectrometry, we identified a series of positively charged stoichiometric zirconium oxide clusters that exhibit enhanced activity and selectivity for three oxidation reactions of widespread chemical importance. Density functional theory calculations reveal that these clusters all contain the same active site consisting of a radical oxygen center with an elongated zirconium−oxygen bond. Calculated energy profiles demonstrate that each oxidation reaction is highly favorable energetically and involves easily surmountable barriers. Furthermore, the active stoichiometric clusters may be regenerated by reacting oxygen-deficient clusters with a strong oxidizer. This indicates that these species may promote multiple cycles of oxidation reactions and, therefore, exhibit true catalytic behavior. The stoichiometric clusters, having structures that resemble specific sites in bulk zirconia, are promising candidates for potential incorporation into a cluster assembled catalyst material.