After the study of the naked cluster, the stabilizing effect was investigated by adding chemisorbed water molecules at the particle surface, with a covering degree ranging from 15% to 100%. The study was performed on ZrO2 cluster models, with a diameter around 1.25 nm, using the Car - Parrinello molecular dynamics method combined with standard structural optimization methods. In this work, we analysed the stabilizing effect of surface impurities on the structure of ultra-small ZrO2 nanoparticles using ab-initio simulation methods. It can be expected that some surface stabilizing mechanisms may occur in real systems, and they could induce more or less pronounced effects on the structure of nanoparticles. more ABSTRACT Real nanoparticles can hardly be considered as isolated objects in vacuum with pure stoichiometric chemical composition. The empirical activation energy of conduction was 0.35 eV, which compares well with the calculated migration energy of 0.32 eV in a previous study.ДЄBSTRACT Real nanoparticles can hardly be considered as isolated objects in vacuum with pure stoi.

The oxide-ion conductivity was determined from the impedance spectroscopy data at 573вЂ“973 K, which steadily increased from 2.4 Г— 10вЂ“3 S/cm to 2.39 Г— 10вЂ“2 S/cm with increasing temperature. The annealed couple was mechanically processed, and the thin-plate electrolyte consisting of the highly c-axis-oriented polycrystal was obtained.

We have also prepared sandwich-type La2Si2O7/La2SiO5/La2Si2O7 diffusion couples and heated them at 1873 K for 100 h. The apatite layer formed at 1873 K was characterized by the steady decrease of the x-value along the diffusion direction from 0.13 at the La2SiO5/apatite interface to 0.01 at the apatite/La2Si2O7 interface. The formation of the apatite layer was controlled by volume diffusion, the overall reaction of which is described by (10 + 6x)La2SiO5 + (4вЂ“3x)La2Si2O7 в†’ 3La9.33+2x(SiO4)6O2+3x (0.01 в‰¤ x в‰¤ 0.13). The product layers were composed of the highly c-axis-oriented prismatic crystallites, with their elongation directions being almost parallel to the diffusion direction. The annealed couples were characterized using optical microscopy, micro-Raman spectroscopy, X-ray diffractometry, and electron probe microanalysis. When the La2SiO5/La2Si2O7 diffusion couples were isothermally heated at 1773вЂ“1873 K for 5вЂ“100 h, the apatite polycrystals were readily produced in the form of a layer at the interfacial boundaries. more ABSTRACT We have successfully synthesized the highly c-axis-oriented polycrystals of apatite-type lanthanum silicate by the reactive diffusion technique. The BVS and DFT studies suggested a change in the ion migration pathway, in which the ion migration through O1 sites becomes more important at temperatures higher than 830 вЊ.ДЄBSTRACT We have successfully synthesized the highly c-axis-oriented polycrystals of apatite-type. The XRPD study indicates that the host structural framework did not change with temperature, while the oxygen/vacancy arrangement in SLF did change at 830 вЊ. This is similar to the ionic conduction behavior reported for Sr3Fe2O7. Enthalpy of the oxygen vacancy formation changed at 830 вЊ. They showed that the oxygen vacancies in SLF are located at the O1 oxygen site, which is on the vertex shared by two FeO6 octahedra in the perovskite layer. The structural analyses of SLF by XRPD and DFT agreed well. To elucidate the ion migration mechanism in Sr2.46La0.54Fe2O7-Оґ (SLF) we used a combination of experimental techniques and computational techniques. The Ruddlesden-Popper perovskite (Sr,La)n+1(Fe,Co)nO3n+1 (n = 2) has characteristic oxygen permeation and ion conduction properties, resulting from the layered perovskite structure. Understanding the oxide ion migration mechanism would provide fundamental insights into the relationships between the structure and properties such as ionic conductivity. more Metal oxides are widely used in devices such as sensors, fuel cells, and oxygen permeation membranes.

Metal oxides are widely used in devices such as sensors, fuel cells, and oxygen permeation membra.

Olivier masson pointcarrГ©