CO Oxidation Mechanism on CeO2-Supported Au Nanoparticles

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• 作者：Hyun You Kim ; Hyuck Mo Lee ; Graeme Henkelman
• 刊名：The Journal of the American Chemical Society
• 出版年：2012
• 出版时间：January 25, 2012
• 年：2012
• 卷：134
• 期：3
• 页码：1560-1570
• 全文大小：751K
• 年卷期：v.134,no.3(January 25, 2012)
• ISSN：1520-5126

文摘

Density functional theory was used to study the CO oxidation catalytic activity of CeO₂-supported Au nanoparticles (NPs). Experimental observations on CeO₂ show that the surface of CeO₂ is enriched with oxygen vacancies. We compare CO oxidation by a Au₁₃ NP supported on stoichiometric CeO₂ (Au₁₃@CeO₂-STO) and partially reduced CeO₂ with three vacancies (Au₁₃@CeO₂-3VAC). The structure of the Au₁₃ NP was chosen to minimize structural rearrangement during CO oxidation. We suggest three CO oxidation mechanisms by Au₁₃@CeO₂: CO oxidation by coadsorbed O₂, CO oxidation by a lattice oxygen in CeO₂, and CO oxidation by O₂ bound to a Au鈥揅e³⁺ anchoring site. Oxygen vacancies are shown to open a new CO oxidation pathway by O₂ bound to a Au鈥揅e³⁺ anchoring site. Our results provide a design strategy for CO oxidation on supported Au catalysts. We suggest lowering the vacancy formation energy of the supporting oxide, and using an easily reducible oxide to increase the concentration of reduced metal ions, which act as anchoring sites for O₂ molecules.