Computational Design of a CeO2-Supported Pd-Based Bimetallic Nanorod for CO Oxidation
详细信息 查看全文
- 作者：Bing Liu ; Zhen Zhao ; Graeme Henkelman ; Weiyu Song
- 刊名：Journal of Physical Chemistry C
- 出版年：2016
- 出版时间：March 17, 2016
- 年：2016
- 卷：120
- 期：10
- 页码：5557-5564
- 全文大小：614K
- ISSN：1932-7455
文摘
Engineering a bimetallic system with complementary chemical properties can be an effective way of tuning catalytic activity. In this work, CO oxidation on CeO2(111)-supported Pd-based bimetallic nanorods was investigated using density functional theory calculations corrected by on-site Coulomb interactions. We studied a series of CeO2(111)-supported Pd-based bimetallic nanorods (Pd–X, where X = Ag, Au, Cu, Pt, Rh, Ru) and found that Pd–Ag/CeO2 and Pd–Cu/CeO2 are the two systems where the binding sites of CO and O2 are distinct; that is, in these two systems, CO and O2 do not compete for the same binding sites. An analysis of the CO oxidation mechanisms suggests that the Pd–Ag/CeO2 system is more effective for catalyzing CO oxidation as compared to Pd–Cu/CeO2 because both CeO2 lattice oxygen atoms and adsorbed oxygen molecules at Ag sites can oxidize CO with low energy barriers. Both the Pd–Ag and Pd–CeO2 interfaces in Pd–Ag/CeO2 were found to play important roles in CO oxidation. The Pd–Ag interface, which combines the different chemical nature of the two metals, not only separates the binding sites of CO and O2 but also opens up active reaction pathways for CO oxidation. The strong metal–support interaction at the Pd–CeO2 interface facilitates CO oxidation by the Mars–van Krevelen mechanism. Our study provides theoretical guidance for designing highly active metal/oxide catalysts for CO oxidation.