Surface reduction properties of ceria-zirconia solid solutions: a first-principles study.

Based on the density functional theory (DFT), the reduction properties of Ce 1- x Zr x O 2 (110) surfaces were systematically calculated using CO as a probe for thermodynamic study, and a large supercell was applied to build the whole composition range ( x = 0.125, 0.250, 0.375, 0.500, 0.625, 0.750, 0.875). From the calculated energy barriers of CO oxidation by lattice oxygen, we found that composition Ce 0.875 Zr 0.125 O 2 exhibited the most promising catalytic effectiveness with the lowest activation energy of 0.899 eV. Moreover, the active surface O 3c ions coordinated by two Zr ions and one Ce ion were facilely released from their bulk positions than the O 3c ions surrounded by two Ce ions and one Zr ion on Ce 0.625 Zr 0.375 O 2 , Ce 0.500 Zr 0.500 O 2 , and Ce 0.375 Zr 0.625 O 2 (110) surfaces. This difference could be explained by the binding strength of O 3c with different neighboring cations.