Effect of Sr substituted La2−xSrxNiO4+δ (x = 0, 0.2, 0.4, 0.6, and 0.8) on oxygen stoichiometry and oxygen transport properties

Inprasit, Thitirat; Wongkasemjit, Sujitra; Skinner, Stephen J.; Burriel, Mónica; Limthongkul, Pimpa

doi:10.1039/c4ra11672k

Cited by 32 publications

(32 citation statements)

References 34 publications

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“…La-based R-P-1 oxides Substitution of La 3+ with a larger cation, such as Sr 2+ , leads to variations in oxygen stoichiometry that consequently affects the oxygen transport and exchange properties. [92] [31], D [21], E [25], F [30], G [56], H [54], I [93], La 1.9 Sr 0.1 NiO 4+δ ( I: [93], D: [21]), and La 1.8 Sr 0.2 NiO 4+δ (J: [40], I: [93]). Figure 4b (for La 2 NiO 4+δ obtained from the same report) are compared, [31] the values for the activation energies for the former two are close to one another, while the latter is significantly lower.…”

Section: Effect Of A-site Substitution On R-p-1 Oxidesmentioning

confidence: 99%

“…[2,5,[25][26][27][28][29] The R-P phases of the first series (n = 1) with the general formula A 2 BO 4+δ are among the most studied for high temperature electrocatalytic/catalytic reactions, due to their stability and highly mobile nature of the hyperstoichiometric oxygen (δ) in their structure. [30][31][32][33][34] The hyperstoichiometric oxygen is accommodated by the oxygen interstitial sites in between adjacent rock-salt layers [21,[35][36][37] and charge compensated by the B-site transition metal, which exists in a mixed valence state [25,[38][39][40].…”

Section: Introductionmentioning

confidence: 99%

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Electro- and thermal-catalysis by layered, first series Ruddlesden-Popper oxides

2016

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First series Ruddlesden-Popper oxides (referred herein as R-P-1, with a formula A n+1 B n O 3n+1 where n = 1) have been used in a number of electrochemical and thermochemical reactions. In this review, we examine in detail the effect of the synthesis methods and the composition of the A and B sites on their electrocatalytic/catalytic activity. Effects on important activity parameters, such as surface exchange coefficient (k), oxygen diffusion coefficient (D), hyperstoichiometry (δ), and electronic conductivity are discussed. We find that synthesis plays an important role in their final structure and hyperstoichiometric oxygen content, which significantly impact their activity. In addition, we show that the composition of the A and B sites has an effect on the catalytic/electrocatalytic activity parameters, such as D, k, δ, and electrical conductivity. The use of these oxides for thermal-catalysis is also discussed. We find that while R-P-1 oxides have been widely implemented for high temperature electrocatalysis, their potential for thermal-catalysis has not been fully explored. Limited reports on thermal-catalysis suggest that the redox properties of the B-site transition metal in these oxides, as well as the oxide's ability to accept and release oxygen under reaction conditions play an important role in their catalytic activity. A perspective on catalysis by R-P-1 oxides is provided at the end of the review.

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Section: Effect Of A-site Substitution On R-p-1 Oxidesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Electro- and thermal-catalysis by layered, first series Ruddlesden-Popper oxides

2016

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“…18,19 However, recently an increase of D* has been observed for compositions with high amount of Sr (x ¼ 0.8). 19 With the aim to improve the chemical stability in oxygen, high-temperature electrical conductivity and electrocatalytic activity of R 2 NiO 4+d for oxygen reduction in the present work we introduced Co 3+ cations in Pr 2 NiO 4+d . This was performed by the simultaneous replacement of the equal amounts of Pr and Ni cations by Sr and Co, respectively, according to the chemical formula Pr 2Àx Sr x Ni 1Àx Co x O 4AEd (x ¼ 0.25; 0.5; 0.75; 1.0).…”

Section: Introductionmentioning

confidence: 99%

Tuning the high-temperature properties of Pr₂NiO_4+δby simultaneous Pr- and Ni-cation replacement

et al. 2016

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Novel Pr 2Àx Sr x Ni 1Àx Co x O 4AEd (x ¼ 0.25; 0.5; 0.75) oxides with the tetragonal K 2 NiF 4-type structure have been prepared. Room-temperature neutron powder diffraction (NPD) study of x ¼ 0.25 and 0.75 phases together with iodometric titration results have shown the formation of hyperstoichiometric oxide for x ¼ 0.25 (d ¼ 0.09(2)) and a stoichiometric one for x ¼ 0.75. High-temperature 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(c)/TEC(a) ¼ 2.4 (x ¼ 0.25) to 4.3 (x ¼ 0.75). High-temperature NPD (HT NPD) study of the x ¼ 0.75 sample reveals that a very high expansion of the axial (Ni/Co)-O bonds (75.7 ppm K À1 in comparison with 9.1 ppm K À1 for equatorial ones) is responsible for such behaviour, and is caused by a temperature-induced transition between low-and high-spin states of Co 3+. This scenario has been confirmed by high-temperature magnetization measurements on a series of Pr 2Àx Sr x Ni 1Àx Co x O 4AEd samples. For compositions with high Ni content (x ¼ 0.25 and 0.5) we synthesised K 2 NiF 4-type oxides Pr 2ÀxÀy Sr x+y (Ni 1Àx Co x)O 4AEd , y ¼ 0.0-0.75 (x ¼ 0.25); y ¼ 0.0-0.5 (x ¼ 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 Ce 2Àx Gd x O 2Àx/2 (GDC) at high temperatures reveal optimal behaviour of Pr 1.35 Sr 0.65 Ni 0.75 Co 0.25 O 4+d. This compound shows stability in oxygen at 900 C and does not react with GDC at least up to 1200 C. It features low TEC of 13 ppm K À1 and high-temperature electrical conductivity in air of 280 S cm À1 at 900 C, thus representing a promising composition for use as a cathode material in intermediate temperature solid oxide fuel cells (IT-SOFC).

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“…The addition of acceptors into the lattice, achieved via substitution of the La site with an alkaline earth, can drive the stoichiometry of the material into oxygen deficiency, because the charge compensation of the Sr = La defects can lead either to electron holes or to oxygen vacancies [26]. Although this general result was confirmed by several authors with model simulations [27][28][29], in the case of the La 2-x Sr x NiO 4+d series, Inprasit et al [30] reported a reduction of the oxygen diffusion coefficient with the increase of Sr doping amount. In addition, also doped nickelate electrodes maintain a considerable reactivity with YSZ and Ce-based electrolytes, probably due to the tendency of the small Ni ion to migrate inside the electrolyte lattice [31,32].…”

Section: Introductionmentioning

confidence: 99%

Copper Doped La_0.8Sr_1.2FeO₄ Ruddlesden‐Popper SOFC Cathode: Synthesis, Characterization and Model Analysis

et al. 2018

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Novel La0.8Sr1.2Fe0.9Cu0.1O4±δ (LSFC) oxides for application as cathodes in SOFCs were prepared with two different synthetic methods: solid‐state‐reaction (SSR) and molten citrate (MC). The XRD, ICP‐OES, SEM, laser granulometry and TG‐DTA techniques were applied for the physico‐chemical characterization. 4‐points DC conductivity measurements and EIS experiments were performed in the electrochemical characterization. Compared to SSR, the MC method allowed to obtain finer powders (∼2 μm vs. ∼5 μm) and required lower calcination temperatures (1,000 °C vs. 1,400 °C). The SSR and MC samples showed similar conductivity (30 S cm−1 at 700 °C) and polarization resistance (1.7 Ω cm2 at 700 °C). The EIS results were analyzed with the equivalent circuits method, and with a physically‐based model for the simulation of the impedance spectra, which indicated that the oxygen reduction mechanism involved the TPB. The MC method revealed preferential, thanks to the lower calcination temperature.

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Effect of Sr substituted La_2−xSr_xNiO_4+δ (x = 0, 0.2, 0.4, 0.6, and 0.8) on oxygen stoichiometry and oxygen transport properties

Cited by 32 publications

References 34 publications

Electro- and thermal-catalysis by layered, first series Ruddlesden-Popper oxides

Electro- and thermal-catalysis by layered, first series Ruddlesden-Popper oxides

Tuning the high-temperature properties of Pr₂NiO_4+δby simultaneous Pr- and Ni-cation replacement

Copper Doped La_0.8Sr_1.2FeO₄ Ruddlesden‐Popper SOFC Cathode: Synthesis, Characterization and Model Analysis

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Effect of Sr substituted La2−xSrxNiO4+δ (x = 0, 0.2, 0.4, 0.6, and 0.8) on oxygen stoichiometry and oxygen transport properties

Cited by 32 publications

References 34 publications

Electro- and thermal-catalysis by layered, first series Ruddlesden-Popper oxides

Electro- and thermal-catalysis by layered, first series Ruddlesden-Popper oxides

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

Copper Doped La0.8Sr1.2FeO4 Ruddlesden‐Popper SOFC Cathode: Synthesis, Characterization and Model Analysis

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Effect of Sr substituted La_2−xSr_xNiO_4+δ (x = 0, 0.2, 0.4, 0.6, and 0.8) on oxygen stoichiometry and oxygen transport properties

Tuning the high-temperature properties of Pr₂NiO_4+δby simultaneous Pr- and Ni-cation replacement

Copper Doped La_0.8Sr_1.2FeO₄ Ruddlesden‐Popper SOFC Cathode: Synthesis, Characterization and Model Analysis