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.

Comparative Study of Electrophoretic Deposition of Doped BaCeO-Based Films on LaNiO and LaBaNiO Cathode Substrates.

This paper presents the results of a comparative study of methods to prevent the loss of barium during the formation of thin-film proton-conducting electrolyte BaCeGdCuO (BCGCuO) on LaNiO-based (LNO) cathode substrates by electrophoretic deposition (EPD). Three different methods of the BCGCuO film coating were considered: the formation of the BCGCuO electrolyte film without (1) and with a protective BaCeO (BCO) film (2) on the LNO electrode substrate and the formation of the BCGCuO electrolyte film on a modified LaBaNiO (LBNO) cathode substrate (3). After the cyclic EPD in six stages, the resulting BCGCuO film (6 μm) (1) on the LNO substrate was completely dense, but the scanning electron microscope (SEM) analysis revealed the absence of barium in the film caused by its intensive diffusion into the substrate and evaporation during the sintering.

Water Uptake and Transport Properties of LaCaScO Proton-Conducting Oxides.

In this study, oxide materials LaCaScO (x = 0.03, 0.05 and 0.

Effect of proton uptake on the structure of energy levels in the band-gap of Sr-doped LaScO: diffuse reflectance spectroscopy and coherent potential approximation calculations.

Features of the energy levels in the band-gap of LaSrScO and the effect on those levels of proton uptake from H and HO atmospheres were studied by diffuse reflectance spectroscopy and coherent potential approximation (CPA) calculations. It was shown that oxygen vacancies appearing due to acceptor doping with Sr form energy levels near the bottom of the conduction band that are strongly hybridized with the states of the nearest atoms. Excitation of electrons from the valence band to these vacancy levels gives rise to an additional absorption band which overlaps with the fundamental absorption edge.

Oxygen surface exchange and diffusion in PrSrNiCoO.

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

A Reversible Protonic Ceramic Cell with Symmetrically Designed Pr₂NiO-Based Electrodes: Fabrication and Electrochemical Features.

Reversible protonic ceramic cells (rPCCs) combine two different operation regimes, fuel cell and electrolysis cell modes, which allow reversible chemical-to-electrical energy conversion at reduced temperatures with high efficiency and performance. Here we present novel technological and materials science approaches, enabling a rPCC with symmetrical functional electrodes to be prepared using a single sintering step. The response of the cell fabricated on the basis of P⁻N⁻BCZD|BCZD|PBN⁻BCZD (where BCZD = BaCeZrDyO, PBN = PrBaNiO, P = Pr₂O₃, N = Ni) is studied at different temperatures and water vapor partial pressures (pH₂O) by means of volt-ampere measurements, electrochemical impedance spectroscopy and distribution of relaxation times analyses.

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.