Microscopic Insight into the Activation of O2 by Au Nanoparticles on ZnO(101) Support

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• 作者：Chuanyi Jia ; Wenhui Zhong ; Mingsen Deng ; Jun Jiang
• 刊名：Journal of Physical Chemistry C
• 出版年：2016
• 出版时间：March 3, 2016
• 年：2016
• 卷：120
• 期：8
• 页码：4322-4328
• 全文大小：637K
• ISSN：1932-7455

文摘

We carry out density functional theory calculations to cast insight on the microscopic mechanism of the activation of O₂ by Au₇ cluster on ZnO(101)-O support. The excellent catalytic activity of Au/ZnO catalyst was ascribed to the distribution of polarized surface charge associated with interface structure. It is found the stoichiometric ZnO(101)-O easily adsorbs and dissociates O₂ to form very stable oxygen-saturated surface. For Au₇ on stoichiometric ZnO(101)-O surface, the two Au atoms neighboring to O could accumulate positive charges, which then upshift the d-band centers toward the Fermi level. These favor the adsorption and dissociation of O₂, providing two Au activation sites. In contrast, for the Au₇ on the oxygen-saturated ZnO(101)-O, all Au atoms become neighboring to O and consequently provide seven activation sites. The workfunction difference between the Au₇ and support induces effective polarized surface charges, substantially promoting O₂ adsorption and dissociation both dynamically and thermodynamically. Further analysis on the effect of different Au positions demonstrates the polarized charge as the microscopic driving force for catalysis. These results would help design of better metal/oxide catalysts by providing important implications for the role of atomic and electronic structures.