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Hydrogen interactions with low-index surface orientations of tungsten
- Source :
- Journal of physics. Condensed matter : an Institute of Physics journal. 31(25)
- Publication Year :
- 2019
-
Abstract
- We report on density functional theory calculations that have been performed to systematically investigate the hydrogen-surface interaction as a function of surface orientation. The interactions that were analyzed include stable atomic adsorption sites, molecular hydrogen dissociation and absorption energies, migration pathways and barriers on tungsten surfaces, and the saturation coverage limits on the (1 1 1) surface. Stable hydrogen adsorption sites were found for all surfaces. For the reconstructed W(1 0 0), there are two primary adsorption sites: namely, the long-bridge and short-bridge sites. The threefold hollow site (3F) was found to be the most stable for W(1 1 0), while the bond-centered site between the first and second layer was found to be most stable for the W(1 1 1) surface. No bound adsorption sites for H2 molecules were found for the W surfaces. Hydrogen (H) migration on both the (1 0 0) and (1 1 0) surfaces is found to have preferred pathways for 1D motion, whereas the smallest migration barrier for net migration of H on the W(1 1 1) surface leads to 2D migration. Although weaker H interactions are predicted for the W(1 1 1) surface compared to the (1 0 0) or (1 1 0) surfaces, we observe higher H surface concentrations of Θ = 4.0 at zero K, possibly due to the corrugated surface structure. These results provide insight into H adsorption, surface saturation coverage and migration mechanisms necessary to describe the evolution from the dilute limit to concentrated coverages of H.
- Subjects :
- Materials science
Hydrogen
Refractory metals
chemistry.chemical_element
02 engineering and technology
Tungsten
021001 nanoscience & nanotechnology
Condensed Matter Physics
01 natural sciences
Dissociation (chemistry)
Adsorption
chemistry
Transition metal
Chemical physics
0103 physical sciences
Molecule
General Materials Science
Density functional theory
010306 general physics
0210 nano-technology
Subjects
Details
- ISSN :
- 1361648X
- Volume :
- 31
- Issue :
- 25
- Database :
- OpenAIRE
- Journal :
- Journal of physics. Condensed matter : an Institute of Physics journal
- Accession number :
- edsair.doi.dedup.....0db87cdfd814e1b68ffbb2244170cf40