Investigation of physico-chemical properties of the complex oxides YBa (Co, Me)2O5+δ (Me = Fe, Ni, Cu) as the cathode material for the intermedium temperature solid oxide fuel cell

Сложные оксиды состава YBaCo2-xMexO5+δ (Me=Fe, Ni, Cu) с 0.0≤x≤1.0 были синтезированы по глицерин-нитратной технологии и аттестованы рентгенографически, термогравиметрически, дилатометрически и с использованием химического анализа. Из рентгенографических данных было установлено, что однофазные сложные оксиды YBaCo2-xFexO5+δ образуются в интервале составов 0.0≤х≤0.7, для медь-замещенных образцов область гомогенности 0.0≤x≤0.6. При замещении кобальта на никель был получен единственный сложный оксид состава YBaCo1.9Ni0.1O5+δ. Кристаллическая структура оксидов YBaCo2-хMeхO5+δ (Me=Fe, Ni, Cu) была описана в рамках тетрагональной ячейки (пр. гр. P4/mmm). Для всех однофазных образцов из рентгенографических данных методом полнопрофильного анализа Ритвелда были вычислены параметры кристаллической решетки. Кислородная нестехиометрия исследуемых твердых растворов была изучена термогравиметрически в интервале температур 298 – 1373 K на воздухе. Установлено, что постепенное замещение кобальта на железо приводит к увеличению содержания кислорода в образцах, а замещение на медь или никель – к его уменьшению. Термическое расширение сложных оксидов состава YBaCo2-xMexO5+δ (Me=Fe, Cu) было изучено на дилотометре Netzsch DIL 402C в интервале температур 298 – 1273 K на воздухе. Химическая совместимость сложных оксидов YBaCo2-xMexO5+δ (Me = Fe, Cu) по отношению к материалу электролита (Ce0.8Sm0.2O2-δ и Zr0.85Y0.15O2-δ) изучена методом контактных отжигов в температурном интервале 1073–1373 K на воздухе, смесь с массовым отношением 1:1 отжигали в течение 24 часов с последующим рентгенографическим анализом.Polycrystalline YBaCo2-xMexO5+δ (Me=Fe, Ni, Cu) samples with 0.0≤x≤1.0 were synthesized by a glycerol-nitrate route and characterized by X-ray diffraction, thermogravimetric and chemical analysis and dilatometry. According to the results of XRD analysis the homogeneity range for the YBaCo2-хFeхO5+δ solid solutions appears within 0.0≤x≤0.7, for the YBaCo2-хCuхO5+δ 0.0≤x≤0.6. Gradual substitution of cobalt by nickel leads to the formation of YBaCo1.9Ni0.1O5+δ. All YBaCo2-xMexO5+δ (Me=Fe, Ni, Cu) solid solutions were founded to have tetragonal structure (sp. gr. P4/mmm). The unit cell parameters were refined using Rietveld full-profile analysis. Oxygen nonstoichiometry of the YBaCo2-xMexO5+δ (Me=Fe, Ni, Cu) solid solutions was measured by means of thermogravimetric technique within the temperature range 298 – 1373 K in air. Gradual substitution of cobalt by iron leads to the increase of oxygen content while introduction of copper or nickel significantly decrease it. Thermal expansion of YBaCo2-xMexO5+δ (Me=Fe, Ni, Cu) were studied using Netzsch DIL 402C dilatometer within the temperature range 298 – 1273 K in air. Chemical compatibility with the electrolyte materials Zr0.85Y0.15O2-δ and Ce0.8Sm0.2O2-δ have been checked within the temperature range 1173–1373 К by means of annealing of the corresponding mixtures with 1:1 weight ratio during 24 h in air with following XRD analysis.Программа развития УрФУ на 2013 год (п.1.2.2.3

Phase equilibria and thermodynamic properties of oxide systems on the basis of rare earth, alkaline earth and 3d-transition (Mn, Fe, Co) metals. A short overview of

Review is dedicated studies of phase equilibria in the systems based on rare earth elements and 3d transition metals. It’s highlighted several structural families of these compounds and is shown that many were found interesting properties for practical application, such as high conductivity up to the superconducting state, magnetic properties, catalytic activity of the processes of afterburning of exhaust gases, the high mobility in the oxygen sublattice and more

Crystal structure and oxygen nonstoichiometry of oxides in the Ba-Me-Me’-Y-O (Me, Me’=Co, Fe) system

Polycrystalline BaМe1-xYxO3-δ(Me=Co, Fe) samples were synthesized by a conventional route and glycerol-nitrate technique. According XRD patterns of single phase solid solutions BaCo1-xYxO3-δ (0.1≤x≤0.4) and BaFe0.9-yY0.1CoyO3-δ (0.05≤y≤0.15) were indexed using Pm3m space group. The unit cell parameters were refined using Rietveld full-profile analysis. Oxygen non-stoichiometry of these solid solutions was measured by means of thermogravimetric technique within the temperature range 298-1273 K in air.The work was supported under financial support from RFBR № 13-03-00958 and Ministry of Science and Education of Russian Federation within the limits of the Federal target program "Scientific and scienceeducational cadres of innovative Russia for 2009-2013"

Phase equilibria, crystal structure and oxygen content of intermediate phases in the Y-Ba-Co-O system

The phase equilibria in the Y-Ba-Co-O system were systematically studied at 1373 K in air. The intermediate phases formed in the Y-Ba-Co-O system at 1373 K in air were: YBaCo2O5+δ, YBaCo4O 7 and BaCo1-yYyO3-δ (0.09≤y≤0.42). It was shown that YBaCo2O5+δ possesses tetragonal structure with the 3ap×3a p×2ap superstructure (sp. gr. P4/mmm). High-temperature X-ray diffraction analysis of the YBaCo2O 5+δ in the temperature range from 298 K up to 1073 K under Po2=0.21 atm has not shown any phase transformations. The value of oxygen content for the YBaCo2O5+δ at room temperature was estimated as 5.40 and at 1323 K it was equal to 5.04. Thermal expansion of sample shows a linear characteristics and the average thermal expansion coefficient (TEC) is about 13.8×10-6, K-1 in the temperature range 298-1273 K. The homogeneity range and crystal structure of the BaCo1-yYyO3-δ (0.09≤y≤0.42) solid solutions were determined by X-ray diffraction of quenched samples. All BaCo1-yYyO3-δ solid solutions were found to have cubic structure (sp. gr. Pm3m). The unit cell parameters were refined using Rietveld full-profile analysis. Oxygen nonstoichiometry of BaCo 1-yYyO3-δ solid solutions with 0.1≤y≤0.4 was measured by means of thermogravimetric technique within the temperature range 298-1373 K in air. Thermal expansion of BaCo 1-yYyO3-δ (y=0.0; 0.1; 0.2; 0.3) samples was studied within the temperature range 298-1200 K in air. The projection of isothermal-isobaric phase diagram for the Y-Ba-Co-O system to the compositional triangle of metallic components was presented. © 2013 Elsevier Inc

Phase Equilibria in the YFeO3 – YCoO3 System in Air

Received: 14.03.2021. Revised: 10.04.2021. Accepted: 11.04.2021. Available online: 13.04.2021.YFe1-xСоxO3 solid solutions were prepared by glycerol-nitrate technique. The homogeneity range of solid solutions was studied within the temperature range 1173 – 1573 K. A continues series of solid solution below the decomposition temperature of YСоO3, which was shown to be equal to 1266 + 6 K, begins to narrow at higher temperatures and becomes equal to 0 ≤ x ≤ 0.1 at 1573 K. The phase diagram of the YFeO3 – YСoO3 system in the “T – composition” coordinates was divided into three fields. Similar to the parent ternary oxides, all single-phase YFe1-xСоxO3 solid solutions possess orthorhombically distorted perovskite structure (Pnma space group). Unusual behavior of orthorhombic distortions in YFe1-xСоxO3 with temperature was explained by probable changes in spin state of Co3+ ions.This work was supported in parts by the Ministry of Sci-ence and Higher Education of Russian Federation (№ АААА-А20-120061990010-7) and A.V.B. was supported with a stipend for young scientists and PhD students from the President of Russian Federation (№ SP-3689.2019.1)

SPECIFIC FEATURES OF PHASE EQUILIBRIUMS IN YFeO3 – YСoO3 SYSTEM IN AIR

YFe1-xCoxO3 phases have been prepared using a glycerol-nitrate technique at 1373 K in air. The X-ray diffraction (XRD) pattern for the single phases were refined by the Rietveld method within the orthorhombic structure (space group Pnma).Работа выполнена при поддержке совета по грантам Президента Российской Фе-дерации стипендии Президента Российской Федерации молодым ученым и аспирантам (Конкурс СП-2019) № СП-3689.2019.1«Получение новых перспективных матери-алов для электрохимических устройств на основе феррита иттрия-бария»

PHASE EQUILIBRIUM IN THE 1/2Dy2O3–SrO–1/2Fe2O3 SYSTEM AT 1100°C

The purpose of investigation is phase equilibria in the 1/2Dy2O3–SrO–1/2Fe2O3 system at 1100°C in air. Solid solution Dy1-xSrxFeO3 (0.0≤x≤0.1, x=0.9) and individual oxide Dy3Fe5O12 were found to form

Synthesis and characterization of the oxygen-deficient perovskite BaFe0.9-xY0.1CoxO3-δ (0 ≤ x ≤ 0.15)

BaFe0.9-xY0.1CoxO3-δ (0 ≤ x ≤ 0.15) is shown to adopt the cubic perovskite structure at temperatures up to 1400 K in air. The oxygen vacancy concentration increases with both cobalt content and temperature, with BaFe0.75Y0.1Co0.15O2.35 being the most oxygen-deficient composition observed. At 700 K the conductivity is ∼2 S cm−1 across the whole composition range. Measurements of the Seebeck coefficient show that holes are the dominant carrier. The coefficient of thermal expansion is essentially constant above 800 K, but not at lower temperatures. Chemical reactivity tests, along with the coefficient of expansion, show that these perovskites would not be suitable electrodes for fuel cells with fluorite electrolytes but they might serve as permeable membranes in catalytic reactors. © 2016 Elsevier Lt

PHASE EQUILIBRIUM IN THE 1/2Dy2O3-SrO-CoO SYSTEM

The purpose of this study is to investigate the phase equilibria in the 1/2Dy2O3-SrO-CoO system at 1100°C in air. At present two binary oxides SrCoO3-δ, Sr3Co2O7-δ and individual oxide Dy0.14Sr0.86CoO3-δ were obtained