Determination of Kinetic Parameters and Identification of the Rate-Determining Steps in the Oxygen Exchange Process for LaNiFeO.

The mixed ionic and electronic oxide LaNiFeO (LNF) is a promising ceramic cathode material for solid oxide fuel cells. Since the reaction rate of oxygen interaction with the cathode material is extremely important, the present work considers the oxygen exchange mechanism between O and LNF oxide. The kinetic dependence of the oxygen/oxide interaction has been determined by two isotopic methods using O-labelled oxygen.

Promising LaMoO-LaMoO Composite Oxygen-Ionic Electrolytes: Interphase Phenomena.

The LaMoO-LaMoO composite materials represent a novel class of highly conductive materials demonstrating increased oxygen-ion conductivity. Extensive research of (100 - )LaMoO-LaMoO composites over a wide range of concentrations ( = 5, 10, 15, 20, 30, and 100) was carried out for the first time. An increase in conductivity, oxygen surface exchange coefficient, and oxygen diffusivity is observed for composites compared to individual oxides, which is associated with the segregation of different ions on the surface of the grains and the formation of a LaMoO new phase at the contact boundary of LaMoO and LaMoO.

Correlation between structure, surface defect chemistry and O/O exchange for LaMoO and La(MoO).

The LaMoO and La(MoO) powders were synthesized using a solid-state reaction method and used to prepare dense ceramics. X-ray photoelectron spectroscopy was used to study the chemical composition and charge numbers of the elements in the subsurface area of dense ceramics of lanthanum molybdates. The spectra were measured under an ultra-high vacuum of 7 × 10 atm at 30 °C and 600 °C, and under an oxygen atmosphere at 2 × 10 atm at 600 °C and 825 °C.

Effect of grain boundaries in LaSrCoO on oxygen diffusivity and surface exchange kinetics.

The single crystal and polycrystalline specimens of La0.84Sr0.16CoO3-δ oxide were synthesized and characterized by X-ray powder diffraction analysis, energy dispersive X-ray microanalysis, the electron backscatter diffraction technique, and X-ray photoelectron spectroscopy.

Oxygen surface exchange and diffusion in mayenite single crystal.

Oxygen surface exchange and diffusion in CaAlO single crystal were studied by a unique in situ method based on isotope equilibration in the gas phase. Although the interphase exchange rate and oxygen diffusion coefficient demonstrate good agreement with available data, only the employed method is efficient to isolate the contributions of various types of exchange; thus, for the first time, it is possible to estimate the surface heterogeneity of mayenite. The obtained results disprove conclusions previously developed in the literature; the temperature region of 750 °C to 850 °C is not the intermediate region where two types of oxygen diffusion coexist.

Oxygen surface exchange and diffusion in PrSrNiCoO.

Oxygen surface exchange and diffusion in Pr1.75Sr0.25Ni0.

Oxygen isotope exchange in La2NiO(4±δ).

Oxygen surface exchange kinetics and diffusion have been studied by the isotope exchange method with gas phase equilibration using a static circulation experimental rig in the temperature range of 600-800 °C and oxygen pressure range of 0.13-2.5 kPa.