Ceria (CeO2) has attracted extensive attention in catalysis due to its oxygen storage capacity (OSC), and the role of ceria in oxidation catalysis is also of particular interest. Many studies has reported that an oxychloride phase can form under reaction conditions or during sample preparation treatments in various heterogeneous catalytic systems.1,2 Herein, we tried to modify ceria by substituting its subsurface O with Cl atom. As Ceria is a reducible oxide, the substitution introduced an extra electron to the system and produced a Ce3+ ions; meanwhile, as the radius of Cl atom is larger than O atom, surface Ce would be pushed upward from the slab due to the repulsive interaction with the larger Cl atom, and such protruding Ce might be an active site. We then used this structure as a model to study the oxidation of CO. We found that this new structure can promote the adsorption of O2, andCO can react with adsorbed O2- species on protruding Ce3+, leaving an O atom behind, and the left O can be consumed by another CO and a new O2 then adsorbs at the Ce3+, thus forming a catalytic circle. In other words, in CO oxidation, the protruding Ce3+ canserve as a permanent active site. To fully understand the interaction between Cl and substrate, we also studied irreducible oxides such as PdO(101) for comparison.References (1) Fajardie, F.; Tempere, O.; Manoli, J. M.; Djega-Mariadassou, G.; Blanchard, G. J. Chem. Soc., Faraday Trans. 1998, 94, 3727-3735.(2) K?pinski, L.; Okal, J. J. Catal. 2000, 192, 48-53.

Using a new model to understand the interaction between Cl species and Ceria: The effect of substituted Cl on the electronic structure of Ceria

248th National Meeting (2014)

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