A theoretic insight into the catalytic activity promotion of CeO2 surfaces by Mn doping

作者：Cen, Wanglai; Liu, Yue^*; Wu, Zhongbiao; Wang, Haiqiang; Weng, Xiaole

来源：Physical Chemistry Chemical Physics, 2012, 14(16): 5769-5777.

DOI：10.1039/c2cp00061j

• TOTAL-ENERGY CALCULATIONS
• MIXED-OXIDE CATALYSTS
• WAVE BASIS-SET
• ELECTRONIC-STRUCTURE
• OXYGEN STORAGE
• 1ST PRINCIPLES
• CO OXIDATION
• REDUCTION
• COMBUSTION
• CERIA

In this paper, we investigated the primary reduction and oxygen replenishing processes over Mn substitutionally doped CeO2(111) surfaces by density functional theory with the on-site Coulomb correction (DFT + U). The results indicated that Mn doping could make the surface much more reducible and the adsorbed O-2 could be effectively activated to form superoxo (O-2(-)) and/or peroxo species (O-2(2-)). The Mn doping induced the Mn 3d-O 2p gap state instead of Ce 4f acting as an electrons acceptor and donor during the first oxygen vacancy formation and O-2 replenishing, which helped to lower the formation energy of the first and second oxygen vacancies to -0.46 eV and 1.40 eV, respectively. In contrast, the formation energy of a single oxygen vacancy in the pure ceria surface was 2.08 eV and only peroxo species were identified as the O-2 molecule adsorbed. Our work provides a theoretical and electronic insight into the catalytic redox processes of Mn doped ceria surfaces, which may help to understand the enhanced catalytic performances of MnOx-CeO2 oxides, as reported in previous experimental works.

• 出版日期2012
• 单位浙江大学