SrMoO Perovskite with Segregated Ru Nanoparticles Performing as Anode in Solid Oxide Fuel Cells.

A new anode material, Ru-SrMoO, with a perovskite structure and segregated metallic Ru, has been tested in an intermediate-temperature solid oxide fuel cell (IT-SOFC) in an electrolyte-supported configuration giving substantial power densities as high as 840 mW/cm at 850 °C using pure H as fuel. This material has been prepared by the citrate method and structurally and microstructurally characterized at room temperature by different techniques such as X-ray diffraction (XRD), neutron powder diffraction (NPD), scanning electron microscopy (SEM), and scanning transmission electron microscopy (STEM). NPD was very useful to determine oxygen positions and vacancies, unveiling a cubic and oxygen-deficient perovskite SrMoO oxide with a 3 space group and potential ionic mobility.

BiCoOF-A Polar, Ferrimagnetic Aurivillius Oxide-Fluoride.

Aurivillius oxides have been a research focus due to their ferroelectric properties, but by replacing oxide ions by fluoride, divalent magnetic cations can be introduced, giving Bi OF ( = Fe, Co, and Ni). Our combined experimental and computational study on BiCoOF indicates a low-temperature polar structure of 2 symmetry (analogous to ferroelectric BiWO) and a ferrimagnetic ground state. These results highlight the potential of Aurivillius oxide-fluorides for multiferroic properties.

Al-Doped SrMoO Perovskites as Promising Anode Materials in Solid Oxide Fuel Cells.

Two perovskite materials with SrMoAlO (x = 0.1, 0.2) compositions have been synthesized by reduction from the corresponding scheelite phases, with SrMoAlO stoichiometry; the pertinent characterization shows that the defective perovskites can be used as anode materials in solid oxide fuel cells, providing maximum output power densities of 633 mW/cm for x = 0.

Tuning between Proper and Hybrid-Improper Mechanisms for Polar Behavior in Cs TiNbO Dion-Jacobson Phases.

The Dion-Jacobson (DJ) family of perovskite-related materials have recently attracted interest due to their polar structures and properties, resulting from hybrid-improper mechanisms for ferroelectricity in = 2 systems and from proper mechanisms in = 3 CsBiTiNbO. We report here a combined experimental and computational study on analogous = 3 Cs TiNbO ( = La, Nd) materials. Density functional theory calculations reveal the shallow energy landscape in these systems and give an understanding of the competing structural models suggested by neutron and electron diffraction studies.

Topotactic Oxidation of Perovskites to Novel SrMoMO (M = Fe and Cr) Deficient Scheelite-Type Oxides.

New polycrystalline SrMoMO (M = Fe and Cr) scheelite oxides have been prepared by topotactical oxidation, by annealing in air at 500 °C, from precursor perovskites with the stoichiometry SrMoMO (M = Fe and Cr). An excellent reversibility between the oxidized Sr(Mo,M)O scheelite and the reduced Sr(Mo,M)O perovskite phase accounts for the excellent behavior of the latter as anode material in solid-oxide fuel cells. A characterization by X-ray powder diffraction (XRD) and neutron powder diffraction (NPD) has been carried out to determine the crystal structure features.