Vibrational properties of protons in hydrated<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mi>Ba</mml:mi><mml:msub><mml:mi>In</mml:mi><mml:mi>x</mml:mi></mml:msub><mml:msub><mml:mi>Zr</mml:mi><mml:mrow><mml:mn>1</mml:mn><mml:mo>−</mml:mo><mml:mi>x</mml:mi></mml:mrow></mml:msub><mml:msub><mml:mi mathvariant="normal">O</mml:mi><mml:mrow><mml:mn>3</mml:mn><mml:mo>−</mml:mo><mml:mi>x</mml:mi><mml:mo>∕</mml:mo><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:ma

Karlsson, Mattias; Björketun, Mårten E.; Sundell, Per; Matic, Aleksandar; Wahnström, Göran; Engberg, Dennis; Börjesson, Lars; Ahmed, Istaq; Eriksson, Sten; Berastegui, P.

doi:10.1103/physrevb.72.094303

Cited by 85 publications

(84 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…As they note, there are no corresponding experimental values for exactly this system, though the value lies within the range of -0.2 to -0.4 eV measured for other materials. Although a recent neutron spin-echo study [50] has examined the proton dynamics in 10% Y-doped BaZrO 3 , no value for the trapping energy is quoted.…”

Section: Quantum Mechanical Calculationsmentioning

confidence: 99%

“…There are several possible reasons for this, including the neglect of quantum effects for the hydrogen nucleus and/or failure to properly describe the vibrations in key regions of the energy surface. Interestingly, the combined experimental and theoretical study of Karlsson et al [50] includes first principles estimated diffusion coefficients that have a prefactor that is too large relative to the measured values. Given the sensitivity of the activation energies to lattice parameter, it may be that thermal expansion and the consequences for the underlying energy surface is the key to the prefactor.…”

Section: Proton Diffusionmentioning

confidence: 99%

See 1 more Smart Citation

Reactive force field simulation of proton diffusion in BaZrO₃using an empirical valence bond approach

Raiteri

Gale

Bussi

2011

J. Phys.: Condens. Matter

View full text Add to dashboard Cite

Abstract.A new reactive force field to describe proton diffusion within the solid-oxide fuel cell material BaZrO 3 has been derived. Using a quantum mechanical potential energy surface, the parameters of an interatomic potential model to describe hydroxyl groups within both pure and yttrium-doped BaZrO 3 have been determined. Reactivity is then incorporated through the use of the empirical valence bond model. Molecular dynamics simulations (EVB-MD) have been performed to explore the diffusion of hydrogen using a stochastic thermostat and barostat whose equations are extended to the isostressisothermal ensemble. In the low concentration limit, the presence of yttrium is found not to significantly influence the diffusivity of hydrogen, despite the proton having a longer residence time at oxygen adjacent to the dopant. This lack of influence is due to the fact that trapping occurs infrequently, even when the proton diffuses through octahedra adjacent to the dopant. The activation energy for diffusion is found to be 0.42 eV, in good agreement with experimental values, though the prefactor is slightly underestimated.

show abstract

Section: Quantum Mechanical Calculationsmentioning

confidence: 99%

Section: Proton Diffusionmentioning

confidence: 99%

Reactive force field simulation of proton diffusion in BaZrO₃using an empirical valence bond approach

Raiteri

Gale

Bussi

2011

J. Phys.: Condens. Matter

View full text Add to dashboard Cite

show abstract

“…23 More recently, Karlsson and co-workers analyzed the O-H IR spectrum of the proton conducting perovskite In:BaZrO 3 , and proposed that different frequency components correspond to specific proton environments in the 2500-3700 cm -1 interval, with red-shifted frequencies corresponding to stronger hydrogen bond configurations. 24 The O-H stretching region of the IR spectrum of LBG20 is shown in Figure 9. It is actually a group of bands extending from 2100 cm -1 to about 3500 cm -1 , that includes contributions ranging from strongly hydrogen bonded configurations to loosely bound hydroxyls.…”

Section: X-ray Diffractionmentioning

confidence: 99%

Crystal Structure and Local Dynamics in Tetrahedral Proton-Conducting La_1-xBa_1+xGaO₄

et al. 2010

View full text Add to dashboard Cite

La 1-x Ba 1+x GaO 4-δ (LBG) compounds, based on unconnected GaO 4 moieties, were recently proposed as proton conductors. Protonic defects in the lattice are inserted through self-doping with Ba 2+ , to create oxygen vacancies subsequently filled by hydroxyl ions. We present a combined structural analysis on self-doped LBG using X-ray diffraction (XRD) and X-ray absorption (EXAFS): these results unravel the finer structural details on the short-range and long-range scales, and they are correlated with the dynamical properties of protonic conduction coming from vibrational spectroscopy. The structure of the GaO 4 groups is independent of the oxide composition. On hydration, an array of short intertetrahedral hydrogen bonds is formed, producing a contraction of the a axis. On the basis of thermogravimetric analysis, EXAFS, XRD and infrared spectroscopy (IR) results, we propose that the stiffness of the GaO 4 tetrahedra hinders the intratetrahedral proton transfer, while the noticeable fraction of protons involved in strong hydrogen bonds limit the proton reorientational freedom.

show abstract

“…13,14 Figure 7 shows the relevant migration paths for the proton around and between oxygens in the first (O1) and second (O2) oxygen coordination shell of a dopant atom A. As seen in Fig.…”

mentioning

confidence: 99%

Quasielastic neutron scattering of hydrated BaZr0.90A0.10O2.95 (A=Y and Sc)

et al. 2009

Self Cite

View full text Add to dashboard Cite

Proton motions in hydrated proton conducting perovskites BaZr0.9A0.10O2.95 (A = Y and Sc) have been investigated using quasielastic neutron scattering. The results reveal a localized motion on the ps time scale and with an activation energy of ∼10-30 meV, in both materials. The temperature dependence of the total mean square displacement of the protons suggests an onset of this motion at a temperature of about 300 K. Comparison of the QENS results to density functional theory calculations suggests that for both materials this motion can be ascribed to intra-octahedral proton transfers occurring close to a dopant atom. The low activation energy, more than ten times lower than the activation energy for the macroscopic proton conductivity, suggests that this motion is not the rate-limiting process for the long-range proton diffusion, i.e. it is not linked to the two materials significantly different proton conductivities.

show abstract

Vibrational properties of protons in hydratedBaInxZr1−xO3−x∕2

Cited by 85 publications

References 23 publications

Reactive force field simulation of proton diffusion in BaZrO₃using an empirical valence bond approach

Reactive force field simulation of proton diffusion in BaZrO₃using an empirical valence bond approach

Crystal Structure and Local Dynamics in Tetrahedral Proton-Conducting La_1-xBa_1+xGaO₄

Quasielastic neutron scattering of hydrated BaZr0.90A0.10O2.95 (A=Y and Sc)

Contact Info

Product

Resources

About

Vibrational properties of protons in hydratedBaInxZr1−xO3−x∕2

Cited by 85 publications

References 23 publications

Reactive force field simulation of proton diffusion in BaZrO3using an empirical valence bond approach

Reactive force field simulation of proton diffusion in BaZrO3using an empirical valence bond approach

Crystal Structure and Local Dynamics in Tetrahedral Proton-Conducting La1-xBa1+xGaO4

Quasielastic neutron scattering of hydrated BaZr0.90A0.10O2.95 (A=Y and Sc)

Contact Info

Product

Resources

About

Reactive force field simulation of proton diffusion in BaZrO₃using an empirical valence bond approach

Reactive force field simulation of proton diffusion in BaZrO₃using an empirical valence bond approach

Crystal Structure and Local Dynamics in Tetrahedral Proton-Conducting La_1-xBa_1+xGaO₄