Oxygen nonstoichiometry and the thermodynamic properties of manganites Ca1 − x − y Sr x La y MnO3 − δ

Leonidova, Ekaterina I.; Markov, A.A.; Патракеев, М.В.; Леонидов, И. А.; Кожевников, В. Л.

doi:10.1134/s003602441102021x

Cited by 6 publications

(2 citation statements)

References 16 publications

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“…[52] By contrast, the increased ionic character of the MnO bond in Pr-rich P91-PCMO suppresses significant OER involvement of lattice O by preventing the formation of O 1− species and V O . [53,54] Its remarkable stability in ETEM experiments suggests that no significant V O formation occurs in contact with H 2 O vapor at positive potentials (Figure 4). Accordingly, in situ XANES at the Mn L-edge of PrMnO 3 showed additional changes compared to Ca-doped specimens, which cannot simply be interpreted as Mn 2+ formation.…”

Section: Corrosion Pathways and Driving Forcesmentioning

confidence: 99%

Environmental TEM Investigation of Electrochemical Stability of Perovskite and Ruddlesden–Popper Type Manganite Oxygen Evolution Catalysts

Mierwaldt

Roddatis

Risch

et al. 2017

Advanced Sustainable Systems

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The sluggish kinetics of the oxygen evolution reaction (OER) is a grand challenge for energy storage technologies. Several perovskites and other oxides of earth‐abundant elements are found to exhibit improved catalytic OER activity. However, less attention is paid to the electrochemical stability, an important factor for large‐scale application. The ongoing search for stable catalysts calls for characterizing active catalyst surfaces and identifying mechanisms of deactivation, activation, or repair. In situ techniques are indispensable for these tasks. This study uses environmental transmission electron microscopy on the highly correlated perovskite Pr1–xCaxMnO3 and the Ruddlesden–Popper Pr0.5Ca1.5MnO4 as model electrodes to elucidate the underlying mechanisms of the stability trends identified on rotating ring disk electrodes. An electron beam at fluxes well below those that would cause radiation damage is used to induce positive local electrode potentials due to secondary electron emission, driving electrochemical reactions in H2O vapor. The stability of the model systems increases with increasing ionic character of the MnO bond, while more covalent bonds are prone to corrosion, which is triggered by formation of point defects in the oxygen sublattice.

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Section: Corrosion Pathways and Driving Forcesmentioning

confidence: 99%

Environmental TEM Investigation of Electrochemical Stability of Perovskite and Ruddlesden–Popper Type Manganite Oxygen Evolution Catalysts

Mierwaldt

Roddatis

Risch

et al. 2017

Advanced Sustainable Systems

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“…Complex oxide systems with a perovskite structure have proven themselves in advanced developments. Among perovskite compounds there are materials with a wide variety of properties, such as mixed ionic and electronic conductivities − and various magnetic, − optical and spectroscopic, , luminescent and dielectric − properties, which determines their widespread use in modern technologies. Such a variety of perovskite properties is due to the great flexibility of the perovskite structure with respect to various modifications and doping of the structure.…”

Section: Introductionmentioning

confidence: 99%

Interaction of O₂ with LSM–YSZ Composite Materials and Oxygen Spillover Effect

et al. 2021

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The interaction between gas-phase oxygen and LSM−YSZ (LSM is La 0.6 Sr 0.4 MnO 3±δ ; YSZ is ZrO 2 •Y 2 O 3 electrolyte) composite catalytic materials was studied by the in situ method based on isotope equilibration with the gas phase at T = 600−850 °C and pO 2 = 0.2−1.3 kPa. We made an attempt to develop mathematical criteria to prove the appearance of the spillover effect [migration of adsorbed particles from the active phase to triple-phase boundary (TPB)] from the experimental data. The heterogeneous exchange rate (r H ) and the three exchange types (r 0 , r 1 , r 2 ) were calculated, where 0, 1, and 2 differ in the number of surface oxide atoms participating during one elementary exchange act. The heterogeneous exchange rate for lanthanum−strontium manganite was 2.5−3 orders higher than the heterogeneous exchange rate for the zirconia-yttria electrolyte over the investigated temperature range. The exchange mechanism of composites LSM−YSZ was different from the LSM and YSZ oxides due to the fact that the ratios between the rates of the three exchange types of composites were also different from the individual phases. An original model was proposed for describing the kinetic dependences taking into account the oxygen exchange at LSM and YSZ individual oxides, at a TPB, and exchange between oxygen forms in an adsorption layer and at a TPB. It was shown, that at 600 °C, the exchange occurred without a significant effect of the exchange on TPB (r TPB ). The exchange on TPB became considerable with increasing temperature, so that at a temperature of 800 °C and higher, the rate-determining stage was the exchange between the forms of oxygen in the adsorption layer and on TPB, corresponding to the spillover effect. The phenomenon of the oxygen spillover effect on LSM−YSZ composites has been considered.

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Co-free triple perovskite La1.5Ba1.5Cu3O7±δ as a promising air electrode material for solid oxide fuel cells

Niemczyk

Świerczek

et al. 2022

Journal of Power Sources

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Oxygen nonstoichiometry and the thermodynamic properties of manganites Ca1 − x − y Sr x La y MnO3 − δ

Cited by 6 publications

References 16 publications

Environmental TEM Investigation of Electrochemical Stability of Perovskite and Ruddlesden–Popper Type Manganite Oxygen Evolution Catalysts

Environmental TEM Investigation of Electrochemical Stability of Perovskite and Ruddlesden–Popper Type Manganite Oxygen Evolution Catalysts

Interaction of O₂ with LSM–YSZ Composite Materials and Oxygen Spillover Effect

Co-free triple perovskite La1.5Ba1.5Cu3O7±δ as a promising air electrode material for solid oxide fuel cells

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Oxygen nonstoichiometry and the thermodynamic properties of manganites Ca1 − x − y Sr x La y MnO3 − δ

Cited by 6 publications

References 16 publications

Environmental TEM Investigation of Electrochemical Stability of Perovskite and Ruddlesden–Popper Type Manganite Oxygen Evolution Catalysts

Environmental TEM Investigation of Electrochemical Stability of Perovskite and Ruddlesden–Popper Type Manganite Oxygen Evolution Catalysts

Interaction of O2 with LSM–YSZ Composite Materials and Oxygen Spillover Effect

Co-free triple perovskite La1.5Ba1.5Cu3O7±δ as a promising air electrode material for solid oxide fuel cells

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Interaction of O₂ with LSM–YSZ Composite Materials and Oxygen Spillover Effect