The Mechanism of Low-Temperature CO Oxidation on IB Group Metals and Metal Oxides

Authors

  • Dr. Zi-Zhang Wei,

    1. Tianjin Environmental Engineering Assessment Center, Tianjin 300191 (P.R. China)
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  • Dui-Chun Li,

    1. College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan 030024 (P.R. China)
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  • Prof. Dr. Xian-Yong Pang,

    1. College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan 030024 (P.R. China)
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  • Dr. Cun-Qin Lv,

    1. College of Chemistry and Chemical Engineering, Shanxi Datong University, Datong 037009, Shanxi Province (P.R. China)
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  • Prof. Dr. Gui-Chang Wang

    Corresponding author
    1. College of Chemistry and Chemical Engineering, Shanxi Datong University, Datong 037009, Shanxi Province (P.R. China)
    2. Department of Chemistry and the Tianjin Key Lab of Metal and Molecule-based Material Chemistry, Nankai University, Tianjin 300071 (P.R. China), Fax: (+86) 22-23502458
    • College of Chemistry and Chemical Engineering, Shanxi Datong University, Datong 037009, Shanxi Province (P.R. China)
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Abstract

CO oxidation on the IB group metals [Cu(111), Ag(111), and Au(111)] and corresponding metal oxides [Cu2O(100), Ag2O(100), and Au2O(100)] has been studied by means of density functional theory calculations with the aim to shed light on the reaction mechanism and catalytic activity of metals and metal oxides. The calculated results show that 1) the molecular oxygen mechanism is favored on Ag(111) and Au(111), but the atomic oxygen mechanism is favored on Cu(111); 2) the metal-terminated metal oxide shows very low activity for CO oxidation; 3) the lattice oxygen can react either with gas phase CO or the absorbed CO molecule on oxygen-terminated metal oxides; and 4) the reaction barrier for CO oxidation follows the order of M2O(100)–O<M(111)<M2O(100)–M (M=Cu, Ag, Au); namely the M2O(100)–O shows higher activity than does the corresponding metal. By analyzing the factor that controls the energy barrier, it was found that the interaction energy between two CO molecules and one O atom at the transition state plays an important role in determining the trend in the barrier.

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