Crystal Structures of the Tetragonal Ceria-Zirconia Solid Solutions CexZr1-xO2 through First Principles Calculations (0 ≤ x ≤ 1)
Crystal Structures of the Tetragonal Ceria-Zirconia Solid Solutions CexZr1-xO2 through First Principles Calculations (0 ≤ x ≤ 1)
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DOI：
10.1021/jp9024156
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发表时间：
2009-06
影响因子：
3.7
通讯作者：
M. Yashima
中科院分区：
文献类型：
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作者：
M. Yashima
通过第一性原理计算（0 ≤ x ≤ 1）研究了亚稳四元化合物CexZr 1 −xO2的晶体结构。采用晶胞参数a = B和α = β = γ = 90°的约束条件，对Ce和Zr原子的所有占位构型的晶胞参数a、c和24个原子的原子坐标进行了优化。随着CeO2含量的增加，基态优化结构的轴比和离规则位置的氧位移减小，这与文献中的衍射实验结果一致. Ce_（0.875）Zr_（0.125）O_2中轴比为1的四方（t”）相是稳定的，而轴比大于1的四方（t '）相和立方相是稳定的。这项工作还证明了CexZr 1 − xO 2（x ≤ 0.75）的基态是t'型。通过与文献中实验数据的比较，讨论了t'和t”型的相位稳定性。
Crystal structures of metastable tetragonal CexZr1−xO2 have been studied through first principles calculations (0 ≤ x ≤ 1). Unit-cell parameters a, c, and atomic coordinates of 24 atoms were optimized for all the occupational configurations of Ce and Zr atoms by using the constraints for cell parameters: a = b and α = β = γ = 90°. Axial ratio and oxygen displacement from the regular position of the optimized structures of ground states decrease with increasing CeO2 content, which is consistent with diffraction experiments in the literature. The tetragonal (t”) form with axial ratio of unity is strongly suggested to be stable in Ce0.875Zr0.125O2, compared with the tetragonal (t’) form with axial ratio larger than unity and the cubic phase. This work also demonstrates that the ground state of CexZr1−xO2 (x ≤ 0.75) is the t’ form. The phase stability of the t’ and t” forms are discussed by comparing the ground states with experimental data in the literature.