Phase Stability and Phase Structure of Ru-Ti-O Complex Oxide Electrocatalyst

作者：Wang, Xin; Shao, Yanqun; Liu, Xuehua; Tang, Dian; Wu, Bo; Tang, Z*******; Wang, Xin; Lin, Wei

来源：Journal of the American Ceramic Society, 2015, 98(6): 1915-1924.

DOI：10.1111/jace.13398

• DENSITY-FUNCTIONAL THEORY
• COMBINED AB-INITIO
• SPINODAL DECOMPOSITION
• SEPARATION
• RUO2-TIO2
• NANOCOMPOSITES
• EQUILIBRIA
• ELECTRODES
• ENERGY

Phase stability of (Ru1-x,Ti-x)O-2 solid solution was investigated via materials computation and X-ray diffraction phase analyses. The unit cell volume of (Ru1-x,Ti-x)O-2 was found not increasing monotonously with the fraction of TiO2, making the volume-composition relationship no longer suitable for the quantitative phase analysis. A monotonous nonlinear c/a-x relation obtained from the ab initio density functional theory (DFT) computation was proved critical to achieving accurate phase analysis results. Gibbs free energy of mixing and its derivatives were determined for (Ru1-x,Ti-x)O-2 by a combination of DFT and thermodynamic calculations, where approximation of the temperature dependence of the interaction parameter () played a critical role. It was found that the conventional approximation method of arbitrarily choosing a value & [10,25] kJ (mole of atoms)(-1) for near a critical temperature of a solid solution structure failed to predict the correct symmetry and span of the miscibility gap for (Ru1-x,Ti-x)O-2. In comparison, calculated from disordered (Ru1-x,Ti-x)O-2 was found a good approximation at the critical temperature. The calculated miscibility gap for (Ru1-x,Ti-x)O-2, therefore, showed good agreement with the accurate quantitative phase analysis results for the samples prepared by a sol-gel method.

• 出版日期2015-6
• 单位福州大学