Improvement in the hydrogen desorption from MgH2 upon transition metals doping: A hybrid density functional calculations

Hussain, Tanveer; Maark, Tuhina Adit; Pathak, Biswarup; Ahuja, Rajeev

doi:10.1063/1.4826521

Cited by 12 publications

(8 citation statements)

References 33 publications

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“…The elongation of Mg–H bond lengths is suggestive of an easier dissociation and consequently reduced hydrogen adsorption energy. These results are in good agreement with those reported by Hussain et al…”

Section: Resultssupporting

confidence: 94%

“…The elongation of Mg−H bond lengths is suggestive of an easier dissociation and consequently reduced hydrogen adsorption energy. These results are in good agreement with those reported by Hussain et al 50 Regarding the electronic structure, Figure 3 shows the total and partial density of states (DOS) curves for the hydride before and after the Nb impurity incorporation. Figure 3a,b shows the hybridization of Mg and H atoms, which is a signal of strong ionic Mg−H bonds.…”

Section: Resultssupporting

confidence: 90%

“…Hussain et al reported similar behavior in Nb-doped α-, βand γ-MgH 2 phases. 50,53 Also, it can be seen that spin-up and spin-down DOS contributions are asymmetric, which is consistent with an induced magnetic moment of 2.11μ B . This induced magnetism comes mainly from the impurity, with a slight polarization of the nearest neighbors.…”

Section: Resultssupporting

confidence: 63%

“…Because of this, an important reduction in the bandgap is found. Hussain et al reported similar behavior in Nb doped -, and -MgH 2 phases50,53 . Also, it can be seen that spin up and spin down DOS contributions are asymmetric, which is consistent with an induced magnetic moment of 2.11μ B .…”

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confidence: 69%

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Effects of Native Vacancies on Nb-Doped MgH₂ Using Density Functional Theory Calculations

et al. 2018

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In the present work we considered the effect of Nb and charged vacancies in the properties of magnesium hydride. We performed spin polarized ab initio calculations substituting a Mg atom by a Nb impurity. Then some charged vacancies were included in the MgH 2 +Nb system (V H , V Mg or V Mg-H). In each case three possible charge states were considered (+1, 0 or-1). We computed cohesion and formation energy, bandgap and magnetic moment. We also calculate the transition level energy value and the density of states. Nb states are located in the gap, and a magnetic moment is induced. In the case of the system with charged vacancies we found that the V H + and V H 0 are the more probable formed and the states near the Fermi level (E F) are filled thus getting an important reduction in the bandgap.

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Section: Resultssupporting

confidence: 94%

Section: Resultssupporting

confidence: 90%

Section: Resultssupporting

confidence: 63%

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confidence: 69%

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Effects of Native Vacancies on Nb-Doped MgH₂ Using Density Functional Theory Calculations

et al. 2018

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“…Improvement of the hydrogen absorption/desorption kinetics is achieved through shortening the path for H diffusion (nanostructures, thin films) or by introducing appropriate dopants which act as catalysts. , In the last years, research has focused on the use of transition metals (TM) as dopants. TMs are considered good candidates to change the hydrogen diffusion kinetics and the stability of MgH 2 . ,− The TM influences the stability of the MgH 2 and causes weakening of the Mg–H bonds. Consequently, TM doping leads to a variation of the cell volume.…”

Section: Introductionmentioning

confidence: 99%

Improvement of Hydrogen Vacancy Diffusion Kinetics in MgH₂ by Niobium- and Zirconium-Doping for Hydrogen Storage Applications

German

Gebauer

2016

J. Phys. Chem. C

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Transition metal (TM) catalytic dopants are broadly used in hydrogen storage materials to increase H2 desorption and absorption kinetics. We have studied H vacancy formation energy in pure, Nb- or Zr- doped bulk magnesium hydride using density functional theory based calculations. The preferential dopant location was determined by means of occupation energy analysis. Both TM species prefer substitutional locations, Zr being more stable than Nb. Five different sites for H vacancy formation have been considered, all of them near the dopant. The vacancy formation energy decreases, especially in the interstitial Zr system in comparison with a pure one (from 1.35 to 0.51 eV). Concerning diffusion, we consider four paths in the pure and doped systems: the doping with TMs diminishes the activation energy barriers improving the diffusion kinetics, being more considerable for Zr. Effects of a possible spin polarization induced in the system by TM atoms and H vacancies generation have been considered as well.

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Improvement in Hydrogen Desorption from β‐ and γ‐MgH₂ upon Transition‐Metal Doping

et al. 2015

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A thorough study of the structural, electronic, and hydrogen-desorption properties of β- and γ-MgH2 phases substituted by selected transition metals (TMs) is performed through first-principles calculations based on density functional theory (DFT). The TMs considered herein include Sc, V, Fe, Co, Ni, Cu, Y, Zr, and Nb, which substitute for Mg at a doping concentration of 3.125 % in both the hydrides. This insertion of TMs causes a variation in the cell volumes of β- and γ-MgH2 . The majority of the TM dopants decrease the lattice constants, with Ni resulting in the largest reduction. From the formation-energy calculations, it is predicted that except for Cu and Ni, the mixing of all the selected TM dopants with the MgH2 phases is exothermic. The selected TMs also influence the stability of both β- and γ-MgH2 and cause destabilization by weakening the MgH bonds. Our results show that doping with certain TMs can facilitate desorption of hydrogen from β- and γ-MgH2 at much lower temperatures than from their pure forms. The hydrogen adsorption strengths are also studied by density-of-states analysis.

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Improvement in the hydrogen desorption from MgH2 upon transition metals doping: A hybrid density functional calculations

Cited by 12 publications

References 33 publications

Effects of Native Vacancies on Nb-Doped MgH₂ Using Density Functional Theory Calculations

Effects of Native Vacancies on Nb-Doped MgH₂ Using Density Functional Theory Calculations

Improvement of Hydrogen Vacancy Diffusion Kinetics in MgH₂ by Niobium- and Zirconium-Doping for Hydrogen Storage Applications

Improvement in Hydrogen Desorption from β‐ and γ‐MgH₂ upon Transition‐Metal Doping

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Improvement in the hydrogen desorption from MgH2 upon transition metals doping: A hybrid density functional calculations

Cited by 12 publications

References 33 publications

Effects of Native Vacancies on Nb-Doped MgH2 Using Density Functional Theory Calculations

Effects of Native Vacancies on Nb-Doped MgH2 Using Density Functional Theory Calculations

Improvement of Hydrogen Vacancy Diffusion Kinetics in MgH2 by Niobium- and Zirconium-Doping for Hydrogen Storage Applications

Improvement in Hydrogen Desorption from β‐ and γ‐MgH2 upon Transition‐Metal Doping

Contact Info

Product

Resources

About

Effects of Native Vacancies on Nb-Doped MgH₂ Using Density Functional Theory Calculations

Effects of Native Vacancies on Nb-Doped MgH₂ Using Density Functional Theory Calculations

Improvement of Hydrogen Vacancy Diffusion Kinetics in MgH₂ by Niobium- and Zirconium-Doping for Hydrogen Storage Applications

Improvement in Hydrogen Desorption from β‐ and γ‐MgH₂ upon Transition‐Metal Doping