Oxygen isotope exchange in doped calcium and barium zirconates

Фарленков, А. С.; Ananyev, M.V.; Еремин, В. А.; Поротникова, Н. М.; Курумчин, Э. Х.; Melekh, B. T.

doi:10.1016/j.ssi.2016.04.015

Cited by 21 publications

(24 citation statements)

References 28 publications

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“…In compounds, the diffusion coefficients D lat and D gb in the previous equations are an effective "molecular" diffusion coefficient, which takes into account the transport of the various ionic species, and usually reduces to that of the slower moving species [34]. In yttrium-doped barium zirconate, oxygen diffuses much faster than cations, with a bulk activation energy of 115 kJ/mol [38]. The creep activation energy of 570 kJ/mol measured in this work can be thus associated with the diffusion energy of cations in 15 at% yttrium-doped barium zirconate.…”

Section: Creep Parametersmentioning

confidence: 99%

High-temperature mechanical behavior of proton-conducting yttrium-doped barium zirconate perovskite

Ciria

Jiménez–Melendo

Aubin

et al. 2021

Journal of the European Ceramic Society

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Section: Creep Parametersmentioning

confidence: 99%

High-temperature mechanical behavior of proton-conducting yttrium-doped barium zirconate perovskite

Ciria

Jiménez–Melendo

Aubin

et al. 2021

Journal of the European Ceramic Society

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“…R 0 O is the oxygen exchange rate of the rate determining step in a consecutive reaction sequence. 7,8 Without violating Maier's universally valid original approach, in the literature 4,[9][10][11][12][13][14] also an effective oxygen exchange rate (1…”

Section: Peter Fielitz* and Gu ¨Nter Borchardtmentioning

confidence: 99%

Oxygen exchange at gas/oxide interfaces: how the apparent activation energy of the surface exchange coefficient depends on the kinetic regime

Fielitz

Borchardt

2016

Phys. Chem. Chem. Phys.

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In the dedicated literature the oxygen surface exchange coefficient KO and the equilibrium oxygen exchange rate [Fraktur R] are considered to be directly proportional to each other regardless of the experimental circumstances. Recent experimental observations, however, contradict the consequences of this assumption. Most surprising is the finding that the apparent activation energy of KO depends dramatically on the kinetic regime in which it has been determined, i.e. surface exchange controlled vs. mixed or diffusion controlled. This work demonstrates how the diffusion boundary condition at the gas/solid interface inevitably entails a correlation between the oxygen surface exchange coefficient KO and the oxygen self-diffusion coefficient DO in the bulk ("on top" of the correlation between KO and [Fraktur R] for the pure surface exchange regime). The model can thus quantitatively explain the range of apparent activation energies measured in the different regimes: in the surface exchange regime the apparent activation energy only contains the contribution of the equilibrium exchange rate, whereas in the mixed or in the diffusion controlled regime the contribution of the oxygen self-diffusivity has also to be taken into account, which may yield significantly higher apparent activation energies and simultaneously quantifies the correlation KO ∝ DO(1/2) observed for a large number of oxides in the mixed or diffusion controlled regime, respectively.

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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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Oxygen isotope exchange in doped calcium and barium zirconates

Cited by 21 publications

References 28 publications

High-temperature mechanical behavior of proton-conducting yttrium-doped barium zirconate perovskite

High-temperature mechanical behavior of proton-conducting yttrium-doped barium zirconate perovskite

Oxygen exchange at gas/oxide interfaces: how the apparent activation energy of the surface exchange coefficient depends on the kinetic regime

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

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Oxygen isotope exchange in doped calcium and barium zirconates

Cited by 21 publications

References 28 publications

High-temperature mechanical behavior of proton-conducting yttrium-doped barium zirconate perovskite

High-temperature mechanical behavior of proton-conducting yttrium-doped barium zirconate perovskite

Oxygen exchange at gas/oxide interfaces: how the apparent activation energy of the surface exchange coefficient depends on the kinetic regime

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

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