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Publications (6 of 6) Show all publications
Nilsson, J. O., Leetmaa, M., Wang, B., Zguns, P., Pašti, I., Sandell, A. & Skorodumova, N. (2018). Modeling Kinetics of Water Adsorption on the Rutile TiO2 (110) Surface: Influence of Exchange-Correlation Functional. Physica status solidi. B, Basic research, 255(3), Article ID 1700344.
Open this publication in new window or tab >>Modeling Kinetics of Water Adsorption on the Rutile TiO2 (110) Surface: Influence of Exchange-Correlation Functional
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2018 (English)In: Physica status solidi. B, Basic research, ISSN 0370-1972, E-ISSN 1521-3951, Vol. 255, no 3, article id 1700344Article in journal (Refereed) Published
Abstract [en]

The accuracy of the theoretical description of materials properties in the framework of density functional theory (DFT) inherently depends on the exchange-correlation (XC) functional used in the calculations. Here we investigate the influence of the choice of a XC functional (PBE, RPBE, PW91, and PBE0) on the kinetics of the adsorption, diffusion and dissociation of water on the rutile TiO2(110) surface using a combined Kinetic Monte Carlo (KMC) – DFT approach, where the KMC simulations are based on the barriers for the aforementioned processes calculated with DFT. We also test how the adsorption energy of intact and dissociated water molecules changes when dispersion interactions are included into the calculations. We consider the beginning of the water layer formation varying coverage up to 0.2 monolayer (ML) at temperatures up to 180 K. We demonstrate that the dynamics of the simulated water–titania system is extremely sensitive to the choice of the XC functional.

Place, publisher, year, edition, pages
Wiley-VCH Verlagsgesellschaft, 2018
Keywords
density functional theory, kinetic Monte Carlo simulations, rutile, surfaces, TiO2, water
National Category
Other Physics Topics
Identifiers
urn:nbn:se:kth:diva-224826 (URN)10.1002/pssb.201700344 (DOI)000427260100018 ()2-s2.0-85043568641 (Scopus ID)
Funder
Swedish Energy Agency, Project No. 35515-1Swedish Research Council
Note

QC 20180327

Available from: 2018-03-27 Created: 2018-03-27 Last updated: 2018-04-04Bibliographically approved
Nilsson, J. O., Vekilova, O. Y., Hellman, O., Klarbring, J., Simak, S. I. & Skorodumova, N. V. (2016). Ionic conductivity in Gd-doped CeO2: Ab initio color-diffusion nonequilibrium molecular dynamics study. Physical Review B. Condensed Matter and Materials Physics, 93(2), Article ID 024102.
Open this publication in new window or tab >>Ionic conductivity in Gd-doped CeO2: Ab initio color-diffusion nonequilibrium molecular dynamics study
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2016 (English)In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 93, no 2, article id 024102Article in journal (Refereed) Published
Abstract [en]

A first-principles nonequilibrium molecular dynamics (NEMD) study employing the color-diffusion algorithm has been conducted to obtain the bulk ionic conductivity and the diffusion constant of gadolinium-doped cerium oxide (GDC) in the 850-1150 K temperature range. Being a slow process, ionic diffusion in solids usually requires simulation times that are prohibitively long for ab initio equilibrium molecular dynamics. The use of the color-diffusion algorithm allowed us to substantially speed up the oxygen-ion diffusion. The key parameters of the method, such as field direction and strength as well as color-charge distribution, have been investigated and their optimized values for the considered system have been determined. The calculated ionic conductivity and diffusion constants are in good agreement with available experimental data.

Place, publisher, year, edition, pages
American Physical Society, 2016
Keywords
TOTAL-ENERGY CALCULATIONS, MONTE-CARLO SIMULATION, WAVE BASIS-SET, ELECTRICAL-PROPERTIES, CERIA, ELECTROLYTES, METALS
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-181360 (URN)10.1103/PhysRevB.93.024102 (DOI)000367662100002 ()2-s2.0-84955318200 (Scopus ID)
Funder
Swedish Energy Agency, 355151Carl Tryggers foundation , CTS 14:433Swedish Research Council, 637-2013-7296Swedish Research Council, 2014-4750Swedish Research Council, 2014-5993
Note

QC 20160205

Available from: 2016-02-05 Created: 2016-02-01 Last updated: 2017-11-30Bibliographically approved
Klarbring, J., Vekilova, O. Y., Nilsson, J. O., Skorodumova, N. V. & Simak, S. I. (2016). Ionic conductivity in Sm-doped ceria from first-principles non-equilibrium molecular dynamics. Solid State Ionics, 296, 47-53
Open this publication in new window or tab >>Ionic conductivity in Sm-doped ceria from first-principles non-equilibrium molecular dynamics
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2016 (English)In: Solid State Ionics, ISSN 0167-2738, E-ISSN 1872-7689, Vol. 296, p. 47-53Article in journal (Refereed) Published
Abstract [en]

Sm-doped ceria is a prospective electrolyte material for intermediate-temperature solid-oxide fuel cells (IT-SOFC). Equi- librium ab initio molecular dynamics (AIMD) studies of oxygen ion diffusion in this material are currently impractical due to the rareness of diffusive events on the accessible timescale. To overcome this issue we have performed ab ini- tio non-equilibrium molecular dynamics calculations of Sm-doped ceria using the color-diffusion algorithm. Applying an external force field we have been able to increase the frequency of diffusive events over the simulation time, while keeping the physical mechanism of diffusion intact. We have investigated the temperature dependence of the maximum strength of the applied external field that could be used while maintaining the response of the system in a linear regime. This allows one to obtain the diffusivity at zero field. The bulk ionic conductivity has been calculated and found to match the experimental data well. We have also compared the description of the diffusion process by our method to previous findings and show that the migration mechanism and site preference of oxygen vacancies with respect to the Sm dopants is well reproduced. 

Place, publisher, year, edition, pages
Elsevier, 2016
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-192499 (URN)10.1016/j.ssi.2016.08.011 (DOI)000386743400009 ()2-s2.0-84986616791 (Scopus ID)
Note

QC 20160913

Available from: 2016-09-13 Created: 2016-09-13 Last updated: 2017-11-21Bibliographically approved
Nilsson, J. O., Leetmaa, M., Vekilova, O. Y., Simak, S. I. & Skorodumova, N. V. (2016). Statistical error in simulations of Poisson processes: Example of diffusion in solids. Physical Review B. Condensed Matter and Materials Physics, 94(8), Article ID 085206.
Open this publication in new window or tab >>Statistical error in simulations of Poisson processes: Example of diffusion in solids
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2016 (English)In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 94, no 8, article id 085206Article in journal (Refereed) Published
Abstract [en]

Simulations of diffusion in solids often produce poor statistics of diffusion events. We present an analytical expression for the statistical error in ion conductivity obtained in such simulations. The error expression is not restricted to any computational method in particular, but valid in the context of simulation of Poisson processes in general. This analytical error expression is verified numerically for the case of Gd-doped ceria by running a large number of kinetic Monte Carlo calculations. 

Place, publisher, year, edition, pages
American Physical Society, 2016
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-192485 (URN)10.1103/PhysRevB.94.085206 (DOI)000383030900005 ()2-s2.0-84985945893 (Scopus ID)
Funder
Swedish Energy Agency, 355151Carl Tryggers foundation , CTS 14:433Swedish Research Council, 2014-5993Swedish Research Council, 2011-42-59
Note

QC 20160913

Available from: 2016-09-13 Created: 2016-09-13 Last updated: 2019-05-20Bibliographically approved
Nilsson, J. O., Leetmaa, M., Wang, B., Zguns, P. A., Sandell, A. & Skorodumova, N. V.Kinetics of water adsorption on the rutile TiO2(110) surface.
Open this publication in new window or tab >>Kinetics of water adsorption on the rutile TiO2(110) surface
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(English)Manuscript (preprint) (Other academic)
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-192505 (URN)
External cooperation:
Note

QC 20160913

Available from: 2016-09-13 Created: 2016-09-13 Last updated: 2016-09-13Bibliographically approved
Nilsson, J. O., Leetmaa, M., Vekilova, O. Y., Simak, S. I. & Skorodumova, N. V.Oxygen diffusion in ceria doped with rare-earth elements.
Open this publication in new window or tab >>Oxygen diffusion in ceria doped with rare-earth elements
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(English)Manuscript (preprint) (Other academic)
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-192504 (URN)
External cooperation:
Note

QC 20160913

Available from: 2016-09-13 Created: 2016-09-13 Last updated: 2016-09-13Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-6083-091X

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