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Interaction of Hydrogen with MB(6) (M = Ba, Ca, La, and Sr) Surfaces from First Principles
We show results of basic energetics and interacting behavior of hydrogen with metal hexaboride surfaces using a combination of self-consistent density functional calculations and dynamics based on the Car–Parrinello method. Our results show that hydrogen is strongly attracted to localized exposed bo...
Autores principales: | , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
American Chemical Society
2019
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Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6649068/ https://www.ncbi.nlm.nih.gov/pubmed/31459312 http://dx.doi.org/10.1021/acsomega.8b02652 |
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author | Schmidt, Kevin M. Misture, Scott T. Graeve, Olivia A. Vasquez, Victor R. |
author_facet | Schmidt, Kevin M. Misture, Scott T. Graeve, Olivia A. Vasquez, Victor R. |
author_sort | Schmidt, Kevin M. |
collection | PubMed |
description | We show results of basic energetics and interacting behavior of hydrogen with metal hexaboride surfaces using a combination of self-consistent density functional calculations and dynamics based on the Car–Parrinello method. Our results show that hydrogen is strongly attracted to localized exposed boron atoms and interactions with the terminal cations are strictly repulsive. From these, preliminary local adsorption energy calculations suggest that a single hydrogen molecule per surface unit-cell is possible (one ML). Strongest bonds are found when hydrogen is above the terminal boron atoms affected by reduced coordination and dangling bonds. This location serves to restore the hexaboride unit to a more stable structure by providing electronic density to the deficient surface octahedra. Additionally, trajectories from dynamic simulations provide insight into how hydrogen recombination reactions occur on the surface through dissociative adsorption and the method of travel prior to recombination to be along the octahedral face and bridging sites connecting separate unit cells on the surface. Upon adsorption, a single hydrogen atom becomes localized at the dangling bond site while the second interacts with the surface along a weaker potential energy path. Desorption at lower temperatures occurs when migrating atoms from separate adsorption sites intersect to form a new pair. |
format | Online Article Text |
id | pubmed-6649068 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2019 |
publisher | American Chemical Society |
record_format | MEDLINE/PubMed |
spelling | pubmed-66490682019-08-27 Interaction of Hydrogen with MB(6) (M = Ba, Ca, La, and Sr) Surfaces from First Principles Schmidt, Kevin M. Misture, Scott T. Graeve, Olivia A. Vasquez, Victor R. ACS Omega We show results of basic energetics and interacting behavior of hydrogen with metal hexaboride surfaces using a combination of self-consistent density functional calculations and dynamics based on the Car–Parrinello method. Our results show that hydrogen is strongly attracted to localized exposed boron atoms and interactions with the terminal cations are strictly repulsive. From these, preliminary local adsorption energy calculations suggest that a single hydrogen molecule per surface unit-cell is possible (one ML). Strongest bonds are found when hydrogen is above the terminal boron atoms affected by reduced coordination and dangling bonds. This location serves to restore the hexaboride unit to a more stable structure by providing electronic density to the deficient surface octahedra. Additionally, trajectories from dynamic simulations provide insight into how hydrogen recombination reactions occur on the surface through dissociative adsorption and the method of travel prior to recombination to be along the octahedral face and bridging sites connecting separate unit cells on the surface. Upon adsorption, a single hydrogen atom becomes localized at the dangling bond site while the second interacts with the surface along a weaker potential energy path. Desorption at lower temperatures occurs when migrating atoms from separate adsorption sites intersect to form a new pair. American Chemical Society 2019-01-02 /pmc/articles/PMC6649068/ /pubmed/31459312 http://dx.doi.org/10.1021/acsomega.8b02652 Text en Copyright © 2019 American Chemical Society This is an open access article published under an ACS AuthorChoice License (http://pubs.acs.org/page/policy/authorchoice_termsofuse.html) , which permits copying and redistribution of the article or any adaptations for non-commercial purposes. |
spellingShingle | Schmidt, Kevin M. Misture, Scott T. Graeve, Olivia A. Vasquez, Victor R. Interaction of Hydrogen with MB(6) (M = Ba, Ca, La, and Sr) Surfaces from First Principles |
title | Interaction of Hydrogen with MB(6) (M = Ba,
Ca, La, and Sr) Surfaces from First Principles |
title_full | Interaction of Hydrogen with MB(6) (M = Ba,
Ca, La, and Sr) Surfaces from First Principles |
title_fullStr | Interaction of Hydrogen with MB(6) (M = Ba,
Ca, La, and Sr) Surfaces from First Principles |
title_full_unstemmed | Interaction of Hydrogen with MB(6) (M = Ba,
Ca, La, and Sr) Surfaces from First Principles |
title_short | Interaction of Hydrogen with MB(6) (M = Ba,
Ca, La, and Sr) Surfaces from First Principles |
title_sort | interaction of hydrogen with mb(6) (m = ba,
ca, la, and sr) surfaces from first principles |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6649068/ https://www.ncbi.nlm.nih.gov/pubmed/31459312 http://dx.doi.org/10.1021/acsomega.8b02652 |
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