Cerium dioxide (Ceria, CeO2) and related materials find applications with extraordinary performance in many important processes such as crude oil refining, production of hydrogen and vehicle emission control. The specific electronic configuration of Ce, in particular its localized 4f orbital, is widely believed to be key to its unique properties, though detailed understanding is still lacking. By using Density Functional Theory calculations corrected by on-site coulomb interaction, we have studied physico-chemical properties of low-index CeO2 surfaces. The processes of O vacancy formation as well as Au clusters adsorption, and the electronic structures of the corresponding reduced systems were systematically investigated. In addition, the chemical processes such as CO oxidation and NO reduction were also calculated at stoichiometric and reduced CeO2 surfaces. It was determined that localized electrons readily occur on reduced CeO2 surfaces with multi-configurations as the result of structural relaxation. More importantly, it has also been found that electron localization at the characteristic 4f orbital of Ce, directly determined by subtle structural relaxation, can give rise to a unique scenario of the various reaction coordinates. Specifically, we have found that the coupled geometric and electronic properties of rare earth species may act as a 'chemical lever' turning tiny structural change of the substrate into drastic electron transfer and accomplishment of reactions. These results may bring us one step ahead toward the comprehensive understanding of catalytic performance of CeO2-based materials.

DFT+U calculations of rare earth CeO<sub>2</sub> for catalysis and energy production

248th National Meeting (2014)

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DFT+U calculations of rare earth CeO2 for catalysis and energy production

DFT+U calculations of rare earth CeO₂ for catalysis and energy production