AVS 62nd International Symposium & Exhibition
    Surface Science Tuesday Sessions
       Session SS+AS+EN-TuA

Paper SS+AS+EN-TuA2
CO Oxidation over Pd Catalysts Supported on Different Low-Index Surfaces of CeO2: A Combined Experimental and Computational Study

Tuesday, October 20, 2015, 2:40 pm, Room 113

Session: Mechanistic Insight of Surface Reactions: Catalysis, ALD, etc. - II
Presenter: Xiao Liu, Huazhong University of Science and Technology, China
Authors: X. Liu, Huazhong University of Science and Technology, China
Y.W. Wen, Huazhong University of Science and Technology, China
Z.Z. Chen, Huazhong University of Science and Technology, China
B. Shan, Huazhong University of Science and Technology, China
R. Chen, Huazhong University of Science and Technology, China
Correspondent: Click to Email
Pd/CeO2 has attracted much attention on the low temperature CO oxidation due to the strong metal-support interactions. In this study, we have systematically investigated the interface properties and CO oxidation activities of Pd catalysts supported on different low-index surfaces of CeO2. The Pd/CeO2 nanorods have been prepared by incipient wetness impregnation method and the exposed surfaces of CeO2 nanorods have been controlled by changing the calcination temperature after their successful synthesis by hydrothermal method. Their catalytic activities in CO oxidation have been tested and the results show that Pd catalysts supported on CeO2 nanorods exposed by (100) and (110) (calcined at 500 ºC) are more activated than that exposed by (111) (calcined at 700 ºC), which is related to the surface oxygen vacancies concentration and the strength of interface interaction. By performing density functional calculations, the surface oxygen activities and the binding strength of Pd clusters on these low-index surfaces of CeO2 have been investigated. The results show that the oxygen vacancy formation energies of (100) and (110) are smaller than that of (111). The binding strength of Pd clusters on these surfaces follows the sequence: (100) > (110) > (111). Furthermore, CO oxidation routes on these surfaces proceeding through the LH, ER and MvK mechanism have been studied. Our studies not only reveal that the catalytic performance of Pd/CeO2 can be tuned by controlling the exposed surface of oxide but also shed light on the interface structures and CO oxidation mechanism of Pd/CeO2 system.