DFT study of Rh-decorated pristine, B-doped and vacancy defected graphene for hydrogen adsorption

Ambrusi, R.E.; Luna, Carla Romina; Juan, Alfredo; Pronsato, M.E.

doi:10.1039/c6ra16604k

Cited by 44 publications

(19 citation statements)

References 91 publications

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“…This work is based on DFT simulations carried out using the Perdew–Burke–Ernzerhof (PBE) functionals ,, and plane-wave ultrasoft pseudopotential implemented in the CASTEP code. , The lattice constants of the graphene model were first fully optimized with a 20 Å vacuum slab. A 5 × 5 × 1 supercell was investigated with a Brillouin zone k -point mesh of 4 × 4 × 1. , The plane-wave basis set was limited to a 380 eV energy cutoff. − The convergence tolerance of energy was taken as 10 –5 eV/atom, and the maximum allowed force and displacement were set as 0.03 eV/Å and 0.001 Å, respectively. , The spin-polarized option was lifted for the pristine as well as the defective graphene. − Atoms of graphene and adsorbate were relaxed during geometry optimization and transition-state search. Transition states were studied using the linear synchronous transit/quadratic synchronous transit (LST/QST) method .…”

Section: Computational Detailsmentioning

confidence: 99%

Mechanistic Study on Graphene Oxidation by KMnO₄ in Solution Phase and Resultant Carbon–Carbon Unzipping

et al. 2020

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We reveal the origins of surface groups on pristine and defective graphene after oxidation with potassium permanganate in aqueous solution. Density functional theory calculations show that the hydroxyl group that is first introduced onto graphene via hydrolysis of permanganate ester plays an important role in the oxidative cutting of graphene. Our results demonstrate that oxidative unzipping of defect-free graphene will occur from the edge and the inner plane simultaneously in terms of comparable maximum barrier heights along these two reaction routes. Divacancy on the defective graphene may accelerate the etching process when the hydroxyl group is introduced at the defect edge. Different from the previous unzipping mechanisms producing graphene flakes with only zigzag edges, our new mechanism involves hydroxyl and both sides of the graphene sheet, which allows richer edge states after oxidative cutting that agree with experimental observations. The detailed molecular insight into the mechanisms for graphene oxidation and fragmentation will be valuable for developing an effective means for graphene manipulation and interpretation of the long-puzzling graphene oxide structure.

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Section: Computational Detailsmentioning

confidence: 99%

Mechanistic Study on Graphene Oxidation by KMnO₄ in Solution Phase and Resultant Carbon–Carbon Unzipping

et al. 2020

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“…To describe isolated adatoms adsorbed onto the host graphene, we must consider that simulations at room temperature have shown that adatoms adsorbed on the surface of graphene can be moved from one position to another, being two minima corresponding energy to the adatom in the center of the hexagon benzene or adatom located a bridge site. In both positions, graphene preserves its flatness, with fewer distortions in the geometry of the C-C bonds near the adatom adsorbed ( [34] and [35]). In general, almost all heavy atoms are likely to hybridize at the hollow site, and most of them hybridize with graphene via s, d or f orbitals [36].…”

Section: Theoretical Modelmentioning

confidence: 99%

Formation of localized magnetic states in graphene in hollow-site adsorbed adatoms

Escudero

Ardenghi

Sourrouille

et al. 2018

Superlattices and Microstructures

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By appplying tight binding model of adatoms in graphene, we study theoretically the localized aspects of the interaction between transition metal atoms and graphene. Considering the electronelectron interaction by adding a Hubbard term in the mean-field approximation, we find the spinpolarized localized and total density of states. We obtain the coupled system of equations for the occupation number for each spin in the impurity and we study the fixed points of the solutions. By comparing the top site and hollow site adsorption, we show that the anomalous broadening of the latter allows to obtain magnetization for small values of the Hubbard parameter. Finally, we model the magnetic boundaries in order to obtain the range of Fermi energies at which magnetization starts. *

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“…In the case of dispersion forces the DFT-D2 Grimme method was considered such as are suggested in the Ref. [36,42], where Van der Waals interactions are described via a simple pair-wise force field, optimized for several popular DFT functionals [43]. The minima of the total energy were found using a conjugate gradient (CG) algorithm.…”

Section: Computational Modelmentioning

confidence: 99%

“…The present calculations show that the Rh adsorption on defective SWCNT is significantly improved by the presence of oxygen on the SWCNT surface. The case of multiple vacancies is not considered because previous studies indicated that Rh adsorption is thermodynamically more stable on single vacancies [36]. The obtained results, report for the first time the induced magnetic moment and changes in the work function and band gap for the adsorbed Rhn cluster on defective (8,0) SWCNT.…”

Section: Introductionmentioning

confidence: 98%

Rhodium clustering process on defective (8,0) SWCNT: Analysis of chemical and physical properties using density functional theory

Ambrusi

Luna

Sandoval

et al. 2017

Applied Surface Science

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Rhodium clustering process on defective (8,0) SWCNT: Analysis of chemical and physical properties using density functional theory, Applied Surface Sciencehttp://dx. HighlightsRh3 and Rh4 clusters prefer to be adsorbed on oxygenated vacancy. Rh adsorption induces a magnetic moment. Rh atom and Rh2 dimer bonded to the defective SWCNT, show a semiconductor behavior. Rh3 and Rh4 show a metallic behavior. AbstractThe Spin-polarized density functional theory is used to study the effect of a single vacancy in a (8,0) single-walled carbon nanotube (SWCNT) on the Rh clustering process. The vacancy is considered oxygenated and non-oxygenated and, in each case, different Rhn cluster sizes (n =1-4) are taken into account. For the analysis of these systems some physical and chemical properties are calculated, such as binding energy (Eb), work function (WF), magnetic moment, charge transfer, bond length, band gap (Eg), and density of state (DOS). From this analysis it can be concluded that: a single Rh atom and Rh2 dimer are adsorbed on vacancy without oxygen, whereas Rh3 and Rh4 clusters prefer to be adsorbed on oxygenated vacancy. In all cases, Rh adsorption induces a magnetic moment. When the Rh atom and Rh2 dimer are bonded to the defective SWCNT, it has been found that they show a semiconductor behavior that could be interesting to use in the spintronic area. In the case of Rh3 and Rh4 clusters our results show a metallic behavior suggesting that these systems are good candidates for nanotube contact.

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DFT study of Rh-decorated pristine, B-doped and vacancy defected graphene for hydrogen adsorption

Abstract: Rh adatom stability on graphene, with and without defects has been investigated by density functional theory (DFT). The feasibility to achieve uniform dispersion for the metallic atom and the hydrogen storage capacity for each system were evaluated.

Cited by 44 publications

References 91 publications

Mechanistic Study on Graphene Oxidation by KMnO₄ in Solution Phase and Resultant Carbon–Carbon Unzipping

Mechanistic Study on Graphene Oxidation by KMnO₄ in Solution Phase and Resultant Carbon–Carbon Unzipping

Formation of localized magnetic states in graphene in hollow-site adsorbed adatoms

Rhodium clustering process on defective (8,0) SWCNT: Analysis of chemical and physical properties using density functional theory

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DFT study of Rh-decorated pristine, B-doped and vacancy defected graphene for hydrogen adsorption

Abstract: Rh adatom stability on graphene, with and without defects has been investigated by density functional theory (DFT). The feasibility to achieve uniform dispersion for the metallic atom and the hydrogen storage capacity for each system were evaluated.

Cited by 44 publications

References 91 publications

Mechanistic Study on Graphene Oxidation by KMnO4 in Solution Phase and Resultant Carbon–Carbon Unzipping

Mechanistic Study on Graphene Oxidation by KMnO4 in Solution Phase and Resultant Carbon–Carbon Unzipping

Formation of localized magnetic states in graphene in hollow-site adsorbed adatoms

Rhodium clustering process on defective (8,0) SWCNT: Analysis of chemical and physical properties using density functional theory

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Mechanistic Study on Graphene Oxidation by KMnO₄ in Solution Phase and Resultant Carbon–Carbon Unzipping

Mechanistic Study on Graphene Oxidation by KMnO₄ in Solution Phase and Resultant Carbon–Carbon Unzipping