Numerical treatment discussion and <i>ab initio</i> computational reinvestigation of physisorption of molecular hydrogen on graphene

Ferre-Vilaplana, Adolfo

doi:10.1063/1.1859278

Cited by 77 publications

(70 citation statements)

References 21 publications

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“…At each point of Z, the H-H distance is allowed to relax. It has been discussed that the MP2 result for the intermolecular binding energy increases with the basis set size [28]. The similarity between the results of three different basis sets, as shown in Fig.…”

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confidence: 63%

Inaccuracy of Density Functional Theory Calculations for Dihydrogen Binding Energetics onto Ca Cation Centers

et al. 2009

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We investigate the mechanism of dihydrogen adsorption onto Ca cation centers, which has been the significant focus of recent research for hydrogen storage. We particularly concentrate on reliability of commonly used density-functional theories, in comparison with correlated wave function theories. It is shown that, irrespective of the chosen exchange-correlation potentials, density-functional theories result in unphysical binding of H 2 molecules onto Ca 1þ system. This suggests that several previous publications could contain a serious overestimation of storage capacity at least in part of their results. DOI: 10.1103/PhysRevLett.103.216102 PACS numbers: 68.43.Bc, 84.60.Ve One of the greatest challenges of scientific communities worldwide is a pollution-free and renewable energy source. Hydrogen storage with high enough volumetric and gravimetric density is particularly important as an energy carrier for a mobile system [1,2]. It has been discussed that, in order for the storage and discharge to be cycled near room temperature, hydrogen adsorbents need to have a binding affinity with the hydrogen molecule of a few tens of kJ/mol [3,4]. Through a very particular chemistry between the open d shell of metal atoms and H 2 molecular orbitals, an optimal strength of hydrogen adsorption can be achieved [5,6]. In order to realize such a chemistry in the form of a practical hydrogen storage system, numerous previous theory articles investigated nanostructures with dispersed transition metal (TM) atoms [3,[7][8][9]. However, experimental trials to synthesize an open-TM-based hydrogen storage system have been unsuccessful for various reasons. The most prominent barrier is the strong tendency of aggregation of TM atoms which renders the suggested models of dispersed TMs rather hyphothetical [10]. As an alternative, numerous research groups are now focused toward the alkaline-earth metals (AEMs) which have less tendency of aggregation and are believed to have similar binding affinity with dihydrogen adsorbates as TMs [11][12][13][14][15]. In particular, the systems of dispersed Ca atoms have been suggested as possessing the most salient properties.In the series of computational searches for hydrogen storage materials, the density-functional theory (DFT) has been used most widely, mainly because of its practicality [16]. However, common implementations of DFT involve approximations in the exchange-correlation potential, and thus the accuracy of DFTs could not be perfectly trusted. In this regard, it is very pertinent to investigate the capability of common forms of DFT for hydrogen adsorption onto AEMs. We show that DFTs deviate significantly from the correlated wave function theories in the description of the dihydrogen adsorption onto the Ca 1þ system. We discuss that the valence configuration of the Ca cation can be sharply switched between 4s and 3d upon hydrogen adsorption [17]. This sort of interaction is not widely noticed, and the reliability of DFTs for that is intriguing in the context of hydrogen storage as wel...

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confidence: 63%

Inaccuracy of Density Functional Theory Calculations for Dihydrogen Binding Energetics onto Ca Cation Centers

et al. 2009

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“…16 The GGA calculations give similar trends as those obtained with LDA, while the adsorption energies of H 2 on TMs are half the LDA values. 5,14,15 As the LDA ͑GGA͒ gives an upper ͑lower͒ bound of van der Waals type binding of hydrogen compared to the highly correlated methods, 5 we give the readers a caveat that our calculated results should be interpreted in such context. Presented below are the LDA results unless specified otherwise.…”

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confidence: 99%

“…12 The electron exchange correlation is treated within local density approximation ͑LDA͒ 13 which is reliable for covalent bonding and static Coulomb interactions. 5,14,15 For a cross check, we repeated part of calculations with the generalized gradient approximation ͑GGA͒ of Perdew-Burke-Enzelhof form. 16 The GGA calculations give similar trends as those obtained with LDA, while the adsorption energies of H 2 on TMs are half the LDA values.…”

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confidence: 99%

Effect of vacancy defects in graphene on metal anchoring and hydrogen adsorption

Kim¹,

Jhi²,

Lim³

et al. 2009

Applied Physics Letters

113

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The dispersion of transition and alkaline-earth metals on defective graphenes is studied using first-principles calculations. The effect of vacancy defects on binding properties of metal atoms to the graphene and with hydrogen molecules is particularly investigated. It is shown that vacancy defects enhance efficiently the metal binding energy and thus its dispersion, particularly for alkaline-earth metals. Mg on vacancy defects shows a substantial increase in its binding energy and hydrogen uptake capacity. Among metals considered, Ca-vacancy complexes are found to exhibit the most favorable hydrogen adsorption characteristics in terms of the binding energy and the capacity.

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“…3 Research on graphene has opened a new era in nanotechnology. The outstanding mechanical, 4 electrical, 5 and physical properties 6 of graphene warrants its use in a variety of areas such as hydrogen technology, 7 electronics, 5 sensing, 8 and drug delivery, 9,10 among many others. The zero band gap of the graphene at point K renders the construction of graphene based field effect transistors very difficult.…”

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confidence: 99%

Adsorbing H2S onto a single graphene sheet: A possible gas sensor

Reshak

Auluck

2014

Journal of Applied Physics

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The electronic structure of pristine graphene sheet and the resulting structure of adsorbing a single molecule of H2S on pristine graphene in three different sites (bridge, top, and hollow) are studied using the full potential linearized augmented plane wave method. Our calculations show that the adsorption of H2S molecule on the bridge site opens up a small direct energy gap of about 0.1 eV at symmetry point M, while adsorption of H2S on top site opens a gap of 0.3 eV around the symmetry point K. We find that adsorbed H2S onto the hollow site of pristine graphene sheet causes to push the conduction band minimum and the valence band maximum towards Fermi level resulting in a metallic behavior. Comparing the angular momentum decomposition of the atoms projected electronic density of states of pristine graphene sheet with that of H2S–graphene for three different cases, we find a significant influence of the location of the H2S molecule on the electronic properties especially the strong hybridization between H2S molecule and graphene sheet.

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Numerical treatment discussion and ab initio computational reinvestigation of physisorption of molecular hydrogen on graphene

Cited by 77 publications

References 21 publications

Inaccuracy of Density Functional Theory Calculations for Dihydrogen Binding Energetics onto Ca Cation Centers

Inaccuracy of Density Functional Theory Calculations for Dihydrogen Binding Energetics onto Ca Cation Centers

Effect of vacancy defects in graphene on metal anchoring and hydrogen adsorption

Adsorbing H2S onto a single graphene sheet: A possible gas sensor

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