Chemical Expansion Due to Hydration of Proton‐Conducting Perovskite Oxide Ceramics

Andersson, Annika Kristina Eriksson; Selbach, Sverre M.; Knee, Christopher S.; Grande, Tor

doi:10.1111/jace.12990

Cited by 94 publications

(138 citation statements)

References 33 publications

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“…• C, 38,39 which is supported by the TGA from previous reports suggesting that the dehydration of proton conducting oxides and associated weight loss only occur significantly at temperature above ∼450…”

Section: Elementary Stepssupporting

confidence: 81%

Effects of H₂O and CO₂on Electrochemical Behaviors of BSCF Cathode for Proton Conducting IT-SOFC

Sun

Cheng

2016

J. Electrochem. Soc.

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Proton conducting intermediate temperature (400-700 • C) solid oxide fuel cells (IT-SOFC) have attracted great interest recently. However, for SOFC operation at intermediate temperature, cathode is often considered to be the main factor limiting the overall cell performance. In this study, Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3-δ (BSCF), which is one of the most active cathode materials and shows significant hydration effect suggesting possible proton conductivity, was investigated as the cathode for proton conducting IT-SOFC at temperature down to ∼450 • C. The stability and compatibility of BSCF cathode with BaZr 0.1 Ce 0.7 Y 0.1 Yb 0.1 O 3-δ (BZCYYb), one of the leading proton conducting electrolyte materials, were studied at intermediate temperature in various atmospheres. In addition, experiments were carried out to understand the electrochemical behaviors of BSCF as a mixed proton, oxide ion and electron conducting cathode using BSCF/BZCYYb/BSCF symmetrical cells in simulated air containing different concentrations of water vapor (H 2 O) and carbon dioxide (CO 2 ), especially at lower temperature of ∼450 • C. The results are analyzed from the underlying oxygen electrode reaction mechanism point of view, and the direction for future research to further improve the cathode for proton conducting IT-SOFC is pointed out.

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Section: Elementary Stepssupporting

confidence: 81%

Effects of H₂O and CO₂on Electrochemical Behaviors of BSCF Cathode for Proton Conducting IT-SOFC

Sun

Cheng

2016

J. Electrochem. Soc.

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“…Experimental data are available online at ftp://itqrepositorio.itq.upv.es/pub/. Tables S1 and S2 References (24)(25)(26)(27) …”

Section: Acknowledgmentsmentioning

confidence: 99%

Direct conversion of methane to aromatics in a catalytic co-ionic membrane reactor

Morejudo

Zanón

Escolástico

et al. 2016

Science

363

242

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Non-oxidative methane dehydroaromatization (MDA:6CH 4 ↔ C 6 H 6 + 9H 2 ) using shapeselective Mo/zeolite catalysts is a technology to exploit stranded natural gas reserves by direct conversion into transportable liquids. The reaction, however, faces two major issues: the onepass conversion/yield is limited by thermodynamics, and the catalyst deactivates fast due to the kinetically-favored formation of coke. Here we show that integration of an electrochemical BaZrO 3 -based membrane exhibiting both proton and oxide ion conductivity into an MDA reactor enables high aromatic yields and outstanding catalyst stability. These effects originate from the simultaneous extraction of hydrogen and distributed injection of oxide ions along the reactor length. Further, we demonstrate that the electrochemical co-ionic membrane reactor enables high carbon efficiencies (up to 80%) significantly improving the techno-economic process viability, and sets the ground for its commercial deployment. One Sentence Summary:The integration of a co-ionic membrane in a MDA reactor remarkably enhances aromatics yield and catalyst lifetime. Main text:

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“…This can be compared with the value r v = 1.18 Å used by Andersson et al [7] in order to obtain an adequate fit to their experimental data. The size of the oxygen vacancy has also been the subject of interest in studies of other perovskite oxides.…”

Section: Size Of the Oxygen Vacancymentioning

confidence: 99%

“…Finite temperatures and thermal fluctuations may also influence the chemical expansion. These effects are not included in this work [7] since our data are determined from fully relaxed configurations, which correspond to zero Kelvin. For the proton quantum fluctuations can also play a role.…”

Section: Chemical Expansion Due To Hydrationmentioning

confidence: 99%

Size and shape of oxygen vacancies and protons in acceptor-doped barium zirconate

et al. 2015

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The defect induced chemical expansion in acceptor-doped barium zirconate is investigated using density-functional theory (DFT) calculations. The two defect species involved in the hydration reaction, the +2 charged oxygen vacancy and the proton interstitial forming a hydroxide ion, are considered both as free defects and in association with the dopants Y, In, Sc and Ga. The defect induced strain tensor λ is introduced, which provides a natural generalisation of the ordinary chemical expansion to three dimensions and to anisotropic distortions. Both the addition of a vacancy and a proton cause anisotropic distortions and a net contraction of the lattice, indicating that both the vacancy and the hydroxide ion are smaller than the oxygen ion. The contraction is considerably larger for the vacancy and the net effect in hydration, when a vacancy is filled and two protons are added, is an expansion, consistent with the experimental findings. The effect of the dopants on the chemical expansion in hydration is found to be quite small, even if it is assumed that both the vacancy and the proton are fully associated with a dopant atom in the lattice.

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Chemical Expansion Due to Hydration of Proton‐Conducting Perovskite Oxide Ceramics

Cited by 94 publications

References 33 publications

Effects of H₂O and CO₂on Electrochemical Behaviors of BSCF Cathode for Proton Conducting IT-SOFC

Effects of H₂O and CO₂on Electrochemical Behaviors of BSCF Cathode for Proton Conducting IT-SOFC

Direct conversion of methane to aromatics in a catalytic co-ionic membrane reactor

Size and shape of oxygen vacancies and protons in acceptor-doped barium zirconate

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Chemical Expansion Due to Hydration of Proton‐Conducting Perovskite Oxide Ceramics

Cited by 94 publications

References 33 publications

Effects of H2O and CO2on Electrochemical Behaviors of BSCF Cathode for Proton Conducting IT-SOFC

Effects of H2O and CO2on Electrochemical Behaviors of BSCF Cathode for Proton Conducting IT-SOFC

Direct conversion of methane to aromatics in a catalytic co-ionic membrane reactor

Size and shape of oxygen vacancies and protons in acceptor-doped barium zirconate

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Product

Resources

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Effects of H₂O and CO₂on Electrochemical Behaviors of BSCF Cathode for Proton Conducting IT-SOFC

Effects of H₂O and CO₂on Electrochemical Behaviors of BSCF Cathode for Proton Conducting IT-SOFC