Structure and stability of small H clusters on graphene
Abstract
The structure and stability of small hydrogen clusters adsorbed on graphene is studied by means of density functional theory (DFT) calculations. Clusters containing up to six H atoms are investigated systematically, with the clusters having either all H atoms on one side of the graphene sheet (cis-clusters) or having the H atoms on both sides in an alternating manner (trans-clusters). The most stable cis-clusters found have H atoms in ortho- and para-positions with respect to each other (two Hs on neighboring or diagonally opposite carbon positions within one carbon hexagon), while the most stable trans-clusters found have H atoms in ortho-trans-positions with respect to each other (two Hs on neighboring carbon positions, but on opposite sides of the graphene). Very stable trans-clusters with 13-22 H atoms were identified by optimizing the number of H atoms in ortho-trans-positions and thereby the number of closed, H-covered carbon hexagons. For the cis-clusters, the associative H(2) d...esorption was investigated. Generally, the desorption with the lowest activation energy proceeds via para-cis-dimer states, i.e., involving somewhere in the H clusters two H atoms that are positioned on opposite sites within one carbon hexagon. H(2) desorption from clusters lacking such H pairs is calculated to occur via hydrogen diffusion causing the formation of para-cis-dimer states. Studying the diffusion events showed a strong dependence of the diffusion energy barriers on the reaction energies and a general odd-even dependence on the number of H atoms in the cis-clusters.
Source:
Physical Review B: Condensed Matter and Materials Physics, 2011, 83, 20Funding / projects:
- Serbian Ministry of Science and Technological Development [141039A], Danish Research Councils
DOI: 10.1103/PhysRevB.83.205426
ISSN: 1098-0121
WoS: 000290896100005
Scopus: 2-s2.0-79961108505
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VinčaTY - JOUR AU - Šljivančanin, Željko AU - Andersen, Mie AU - Hornekaer, Liv AU - Hammer, Bjork PY - 2011 UR - https://vinar.vin.bg.ac.rs/handle/123456789/4324 AB - The structure and stability of small hydrogen clusters adsorbed on graphene is studied by means of density functional theory (DFT) calculations. Clusters containing up to six H atoms are investigated systematically, with the clusters having either all H atoms on one side of the graphene sheet (cis-clusters) or having the H atoms on both sides in an alternating manner (trans-clusters). The most stable cis-clusters found have H atoms in ortho- and para-positions with respect to each other (two Hs on neighboring or diagonally opposite carbon positions within one carbon hexagon), while the most stable trans-clusters found have H atoms in ortho-trans-positions with respect to each other (two Hs on neighboring carbon positions, but on opposite sides of the graphene). Very stable trans-clusters with 13-22 H atoms were identified by optimizing the number of H atoms in ortho-trans-positions and thereby the number of closed, H-covered carbon hexagons. For the cis-clusters, the associative H(2) desorption was investigated. Generally, the desorption with the lowest activation energy proceeds via para-cis-dimer states, i.e., involving somewhere in the H clusters two H atoms that are positioned on opposite sites within one carbon hexagon. H(2) desorption from clusters lacking such H pairs is calculated to occur via hydrogen diffusion causing the formation of para-cis-dimer states. Studying the diffusion events showed a strong dependence of the diffusion energy barriers on the reaction energies and a general odd-even dependence on the number of H atoms in the cis-clusters. T2 - Physical Review B: Condensed Matter and Materials Physics T1 - Structure and stability of small H clusters on graphene VL - 83 IS - 20 DO - 10.1103/PhysRevB.83.205426 ER -
@article{ author = "Šljivančanin, Željko and Andersen, Mie and Hornekaer, Liv and Hammer, Bjork", year = "2011", abstract = "The structure and stability of small hydrogen clusters adsorbed on graphene is studied by means of density functional theory (DFT) calculations. Clusters containing up to six H atoms are investigated systematically, with the clusters having either all H atoms on one side of the graphene sheet (cis-clusters) or having the H atoms on both sides in an alternating manner (trans-clusters). The most stable cis-clusters found have H atoms in ortho- and para-positions with respect to each other (two Hs on neighboring or diagonally opposite carbon positions within one carbon hexagon), while the most stable trans-clusters found have H atoms in ortho-trans-positions with respect to each other (two Hs on neighboring carbon positions, but on opposite sides of the graphene). Very stable trans-clusters with 13-22 H atoms were identified by optimizing the number of H atoms in ortho-trans-positions and thereby the number of closed, H-covered carbon hexagons. For the cis-clusters, the associative H(2) desorption was investigated. Generally, the desorption with the lowest activation energy proceeds via para-cis-dimer states, i.e., involving somewhere in the H clusters two H atoms that are positioned on opposite sites within one carbon hexagon. H(2) desorption from clusters lacking such H pairs is calculated to occur via hydrogen diffusion causing the formation of para-cis-dimer states. Studying the diffusion events showed a strong dependence of the diffusion energy barriers on the reaction energies and a general odd-even dependence on the number of H atoms in the cis-clusters.", journal = "Physical Review B: Condensed Matter and Materials Physics", title = "Structure and stability of small H clusters on graphene", volume = "83", number = "20", doi = "10.1103/PhysRevB.83.205426" }
Šljivančanin, Ž., Andersen, M., Hornekaer, L.,& Hammer, B.. (2011). Structure and stability of small H clusters on graphene. in Physical Review B: Condensed Matter and Materials Physics, 83(20). https://doi.org/10.1103/PhysRevB.83.205426
Šljivančanin Ž, Andersen M, Hornekaer L, Hammer B. Structure and stability of small H clusters on graphene. in Physical Review B: Condensed Matter and Materials Physics. 2011;83(20). doi:10.1103/PhysRevB.83.205426 .
Šljivančanin, Željko, Andersen, Mie, Hornekaer, Liv, Hammer, Bjork, "Structure and stability of small H clusters on graphene" in Physical Review B: Condensed Matter and Materials Physics, 83, no. 20 (2011), https://doi.org/10.1103/PhysRevB.83.205426 . .