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

摘要

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.