Tuning the high-temperature properties of Pr2NiO4+δ by simultaneous Pr- and Ni-cation replacement

Istomin, S.Y.; Karakulina, O.M.; Rozova, M.G.; Kazakov, S.M.; Gippius, A.A.; Antipov, E.V.; Bobrikov, I.A.; Balagurov, A.M.; Tsirlin, A.A.; Michau, A.; Biendicho, J.J.; Svensson, G.

Авторы: Istomin S.Ya, Karakulina O.M., Rozova M.G., Kazakov S.M., Gippius A.A., Antipov E.V., Bobrikov I.A., Balagurov A.M., Tsirlin A.A., Michau A., Biendicho J.J., Svensson G.
Журнал: RSC advances
Том: 6
Год издания: 2016
Издательство: Royal Society of Chemistry
Местоположение издательства: United Kingdom
Первая страница: 33951
Последняя страница: 33958
DOI: 10.1039/C6RA03099H
Аннотация: Novel Pr2-xSrxNi1-xCoxO4±δ (x = 0.25; 0.5; 0.75) oxides with the tetragonal K2NiF4-type structure have been prepared. Roomtemperature neutron powder diffraction (NPD) study of x=0.25 and 0.75 phases together with iodometric titration results have shown the formation of hyperstoichiometric oxide for x=0.25 (δ=0.09(2)) and a stoichiometric one for x=0.75. Hightemperature X-ray powder diffraction (HT XRPD) showed substantial anisotropy of the thermal expansion coefficient (TEC) along the a- and c-axis of the crystal structure, which increases with increasing the Co content from TEC(с)/TEC(a)=2.4 (x=0.25) to 4.3 (x=0.75). High-temperature NPD (HT NPD) study of the x=0.75 sample reveals that a very high expansion of the axial (Ni/Co)-O bonds (75.7 ppm K-1 in comparison with 9.1 ppm K-1 for equatorial one) is responsible for such behaviour and is caused by a temperature-induced transition between low- and high-spin states of Co3+. This scenario has been confirmed by high-temperature magnetization measurements on a series of Pr2-xSrxNi1-xCoxO4±δ samples. For compositions with high Ni-content (x=0.25 and 0.5) we synthesised K2NiF4-type oxides Pr2-x--ySrx+y(Ni1-xCox)O4±δ, y=0.0-0.75 (x=0.25) ; y=0.0-0.5 (x=0.5). The studies of the TEC, high-temperature electrical conductivity in air, chemical stability of the prepared compounds in oxygen and toward interaction with Ce2-xGdxO2-x/2 (GDC) at high temperatures reveal optimal behaviour of Pr1.35Sr0.65Ni0.75Co0.25O4+δ. This compound shows stability in oxygen at 900oC and does not react with GDC at least up to 1250oC. It features low TEC of 13 ppm K-1 and high-temperature electrical conductivity in air of 280 S/cm at 900oC thus representing promising composition for use as cathode material in the intermediate temperature solid oxide fuel cells (IT-SOFC).
Добавил в систему: Истомин Сергей Яковлевич

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Tuning the high-temperature properties of Pr2NiO4+δ by simultaneous Pr- and Ni-cation replacementстатья

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