H2 Desorption from MgH2 Surfaces with Steps and Catalyst-Dopants

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dc.contributor.author Reich, J.
dc.contributor.author Wang, Lin-Lin
dc.contributor.author Johnson, Duane
dc.contributor.author Johnson, Duane
dc.contributor.department Ames Laboratory
dc.date 2018-02-17T00:00:17.000
dc.date.accessioned 2020-06-29T23:26:25Z
dc.date.available 2020-06-29T23:26:25Z
dc.date.copyright Wed Jan 01 00:00:00 UTC 2014
dc.date.issued 2014-03-20
dc.description.abstract <p>Light-metal hydrides, like MgH2, remain under scrutiny as prototypes for reversible H-storage materials. For MgH2, we assess hydrogen desorption/adsorption properties (enthalpy and kinetic barriers) for stepped, catalyst-doped surfaces occurring, e.g., from ball-milling in real samples. Employing density functional theory and simulated annealing in a slab model, we studied initial H2 desorption from stepped surfaces with(out) titanium (Ti) catalytic dopant. Extensive simulated annealing studies were performed to find the dopant’s site preferences. For the most stable initial and final (possibly magnetic) states, nudged elastic band (NEB) calculations were performed to determine the H2-desorption activation energy. We used a moment-transition NEB method to account for the dopant’s transition to the lowest-energy magnetic state at each image along the band. We identify a dopant-related surface-desorption mechanism that reloads via bulk H diffusion. While reproducing the observed bulk enthalpy of desorption, we find a decrease of 0.24 eV (a 14% reduction) in the activation energy on doped stepped surface; together with a 22% reduction on a doped flat surface, this brackets the assessed 18% reduction in kinetic barrier for ball-milled MgH2 samples with low concentration of Ti from experiment.</p>
dc.description.comments <p>Reprinted with permission from <em>J. Phys. Chem. C</em>. <strong>2014</strong>. 118(13), pp. 6641–6649, doi:<a href="http://dx.doi.org/10.1021/jp412826u" target="_blank">10.1021/jp412826u</a>. Copyright 2014 American Chemical Society.</p>
dc.format.mimetype application/pdf
dc.identifier archive/lib.dr.iastate.edu/ameslab_pubs/272/
dc.identifier.articleid 1276
dc.identifier.contextkey 7549099
dc.identifier.s3bucket isulib-bepress-aws-west
dc.identifier.submissionpath ameslab_pubs/272
dc.identifier.uri https://dr.lib.iastate.edu/handle/20.500.12876/7826
dc.language.iso en
dc.source.bitstream archive/lib.dr.iastate.edu/ameslab_pubs/272/0-2014_Reich_H2Desorption_License.pdf|||Fri Jan 14 23:06:42 UTC 2022
dc.source.bitstream archive/lib.dr.iastate.edu/ameslab_pubs/272/2014_Reich_H2Desorption.pdf|||Fri Jan 14 23:06:43 UTC 2022
dc.source.uri 10.1021/jp412826u
dc.subject.disciplines Catalysis and Reaction Engineering
dc.subject.disciplines Materials Science and Engineering
dc.subject.disciplines Physical Chemistry
dc.subject.keywords Materials Science and Engineering
dc.supplemental.bitstream 2014_Reich_H2Desorption_License.pdf
dc.title H2 Desorption from MgH2 Surfaces with Steps and Catalyst-Dopants
dc.type article
dc.type.genre article
dspace.entity.type Publication
relation.isAuthorOfPublication ed24845f-863f-4613-9f76-130602a21b4a
relation.isOrgUnitOfPublication 25913818-6714-4be5-89a6-f70c8facdf7e
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