Catalytic activities of CeO2(110)-2 x 1 reconstructed surface

Density functional theory calculations with on-site Coulomb interaction correction (DFT + U) have been performed to study the structures and catalytic activities of 2 x 1 reconstructed surface of CeO2(110). The reconstructed surface gives better thermal stability compared with the bulk truncated one and exhibits unique surface activity. We comprehensively calculated the O vacancy formation and diffusion on the reconstructed surface and found that the vacancy formation energy corresponding to the removal of one subsurface four-fold coordinated O is 1.71 eV only, which is smaller than that of the top-surface O vacancy or the sub-surface O vacancy at the bulk truncated surface. Accordingly, the O vacancy diffusion at 2 x 1 reconstructed surface is also much more feasible than that at the unreconstructed CeO2(110) with the highest diffusion barrier of only 0.84 eV. By calculating the detailed pathways of CO reaction with lattice O, we found that CO2 can directly occur without forming a bent negatively charged CO2- intermediate on the reconstructed surface, which may reduce the chance for the carbonate formation. It has also been clearly shown that strong localization characteristics of Ce 4f orbital indeed favor electron transfer from reaction intermediates to the CeO2 support. (C) 2014 Elsevier B.V. All rights reserved.