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  • 1.
    Hussain, Tanveer
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi.
    Computational Insights on Functional Materials for Clean Energy Storage: Modeling, Structure and Thermodynamics2013Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The exponential increase in the demands of world’s energy and the devastating effects of current fossil fuels based sources has forced us to reduce our dependence on the current sources as well as finding cleaner, cheaper and renewable alternates. Being abundant, efficient and renewable, hydrogen can be opted as the best possible replacement of the diminishing and harmful fossil fuels. But the transformation towards the hydrogen-based economy is hindered by the unavailability of suitable storage medium for hydrogen. First principles calculations based on density functional theory has been employed in this thesis to investigate the structures modelling and thermodynamics of various efficient materials capable of storing hydrogen under chemisorption and physisorption mechanisms.

    Thanks to their high storage capacity, abundance and low cost, metal hydride (MgH2) has been considered as promising choice for hydrogen storage. However, the biggest drawback is their strong binding with the absorbed hydrogen under chemisorption, which make them inappropriate for operation at ambient conditions. Different strategies have been applied to improve the thermodynamics including doping with light and transitions metals in different phases of MgH2 in bulk form.  Application of mechanical strain along with Al, Si and Ti doping on MgH2 (001) and (100) surfaces has also been found very useful in lowering the dehydrogenation energies that ultimately improve adsorption/desorption temperatures.

    Secondly, in this thesis, two-dimensional materials with high surface area have been studied for the adsorption of hydrogen in molecular form (H2) under physisorption. The main disadvantage of this kind of storage is that the adsorption of H2 with these nanostructures likes graphane, silicene, silicane, BN-sheets, BC3 sheets are low and demand operation at cryogenic conditions. To enhance the H2 binding and attain high storage capacity the above-mentioned nanostructures have been functionalized with light metals (alkali, alkaline) and polylithiated species  (OLi2, CLi3, CLi4). The stabilities of the designed functional materials for H2 storage have been verified by means of molecular dynamics simulations.

    Delarbeid
    1. Structural, electronic and thermodynamic properties of Al- and Si-doped alpha-, gamma-, and beta-MgH2: Density functional and hybrid density functional calculations
    Åpne denne publikasjonen i ny fane eller vindu >>Structural, electronic and thermodynamic properties of Al- and Si-doped alpha-, gamma-, and beta-MgH2: Density functional and hybrid density functional calculations
    2012 (engelsk)Inngår i: International journal of hydrogen energy, ISSN 0360-3199, E-ISSN 1879-3487, Vol. 37, nr 11, s. 9112-9122Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    In this work, we present a detailed study of Al- and Si-doped alpha-, gamma-, and beta-MgH2 phases using the gradient corrected density functional GGA-PBE and the hybrid Hartree-Fock density functionals PBE0 and HSE06 within the framework of generalized Kohn-Sham density functional theory (DFT) using a plane-wave basis set. We investigate the structural, electronic, and thermodynamical properties of these compounds with regard to their hydrogen storage effectiveness. PBE0 and HSE06 predict cell parameters and bond lengths that are in good agreement with the GGA-PBE calculations and previously known experimental results. As expected smaller band gaps (E(g)s) are predicted by GGA-PBE for the pure magnesium hydride phases. PBE0 overcomes the deficiencies of DFT in treating these materials better than HSE06 and yields E(g)s that compare even better with previous GW calculations. Both the hybrid functionals increase the E(g)s of the Al-doped magnesium hydrides by much less magnitudes than of the Si-doped phases. This difference is interpreted in terms of charge density distributions. Best H-2 adsorption energies (Delta H-ads) are computed by HSE06 while GGA-PBE significantly overestimates them. Si-doped alpha- and beta-MgH2 exhibited the least negative Delta H-ads in close proximity to the H-2 binding energy range of -0.21 to -0.41 eV ideal for practical H-2 storage transportation applications.

    Emneord
    Hybrid density functionals, Magnesium hydride, Hydrogen storage, Density of states
    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-177237 (URN)10.1016/j.ijhydene.2012.03.038 (DOI)000304976300021 ()
    Tilgjengelig fra: 2012-07-09 Laget: 2012-07-04 Sist oppdatert: 2017-12-07bibliografisk kontrollert
    2. Transition Metals Doped MgH2 for Hydrogen Storage: A Hybrid Density Functional Calculations
    Åpne denne publikasjonen i ny fane eller vindu >>Transition Metals Doped MgH2 for Hydrogen Storage: A Hybrid Density Functional Calculations
    2013 (engelsk)Inngår i: AIP AdvancesArtikkel i tidsskrift (Fagfellevurdert) Submitted
    Abstract [en]

    In this study, we have investigated the structural, electronic and thermodynamic

    properties of MgH2 doped with selected transition metals (TMs) by means of hybrid

    density functional theory (PBE0). On the structural side, the calculated lattice

    parameters and equilibrium volumes increase in case of Sc, Zr and Y opposite to all

    the other dopants indicating volumetrically increased hydrogen density. Except Fe, all

    the dopants improve the kinetics of MgH2 by reducing the heat of adsorption with Cu,

    Nb, Ni and V proving more efficient than others studied TM’s. The electronic

    properties have been studied by density of states and correlated with hydrogen

    adsorption energies.

    sted, utgiver, år, opplag, sider
    Uppsala: , 2013
    Emneord
    Transition metals, Desorption energy, Hydrogen Storage
    HSV kategori
    Forskningsprogram
    Fysik med inriktning mot atom- molekyl- och kondenserande materiens fysik
    Identifikatorer
    urn:nbn:se:uu:diva-206633 (URN)
    Tilgjengelig fra: 2013-09-02 Laget: 2013-09-02 Sist oppdatert: 2014-01-23bibliografisk kontrollert
    3. Strain and doping effects on the energetics of hydrogen desorption from the MgH2 (001) surface
    Åpne denne publikasjonen i ny fane eller vindu >>Strain and doping effects on the energetics of hydrogen desorption from the MgH2 (001) surface
    Vise andre…
    2013 (engelsk)Inngår i: Europhysics letters, ISSN 0295-5075, E-ISSN 1286-4854, Vol. 101, nr 2, s. 27006-Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    On the basis of first-principles calculations we have systematically investigated the energetics of hydrogen desorption from the MgH2 (001) surface. Based on total energy and electronic structure calculations, two modes namely strain and doping of selected dopants (Al, Si, Ti) and the combined effect of both on the dehydrogenation energies (Delta H) of MgH2 (001) systems have been analyzed. The maximum improvement in Delta H has been obtained with the combined effect of doping and strain. Among all the dopants, Al gives the lowest value of Delta H when the system Al-MgH2 is subjected to a 7.5% biaxial symmetric strain whereas the Si-MgH2 systems show the least improvement in Delta H. The doping of Ti on MgH2 (001) is also very beneficial even without strain. The reduction in Delta H is caused by the charge localization on the metal atoms, destabilization and the weakening of metal-hydrogen bonds.

    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-197485 (URN)10.1209/0295-5075/101/27006 (DOI)000314677100029 ()
    Tilgjengelig fra: 2013-03-26 Laget: 2013-03-26 Sist oppdatert: 2017-12-06bibliografisk kontrollert
    4. The effects of strain and doping on the release of hydrogen fromthe MgH2(110) surface
    Åpne denne publikasjonen i ny fane eller vindu >>The effects of strain and doping on the release of hydrogen fromthe MgH2(110) surface
    Vise andre…
    2013 (engelsk)Inngår i: Computational Material ScienceArtikkel i tidsskrift (Fagfellevurdert) Submitted
    Abstract [en]

    In this letter, density functional theory has been employed to investigate the release or

    desorption of hydrogen from the MgH2(110) surface. To improve upon the energetics for hydrogen

    desorption from this system, the effects of strain and doping by Al, Si, Ti have been explored.

    Both of these two effects have been found to be effective. The strain applied along the X direction

    induces more prominent effects than along the Y direction. Regarding the doping, the system

    doped with Al gives the most noticeable effect. The Si doped system shows the least improvement

    while the Ti doped system lies in between as compared to the other two. The combination of

    doping and strain effects is found to be more efficacious.

    sted, utgiver, år, opplag, sider
    Uppsala: Stockholm, 2013
    HSV kategori
    Forskningsprogram
    Fysik med inriktning mot atom- molekyl- och kondenserande materiens fysik
    Identifikatorer
    urn:nbn:se:uu:diva-206634 (URN)
    Tilgjengelig fra: 2013-09-02 Laget: 2013-09-02 Sist oppdatert: 2014-01-23bibliografisk kontrollert
    5. Ab initio study of lithium-doped graphane for hydrogen storage
    Åpne denne publikasjonen i ny fane eller vindu >>Ab initio study of lithium-doped graphane for hydrogen storage
    Vise andre…
    2011 (engelsk)Inngår i: Europhysics letters, ISSN 0295-5075, E-ISSN 1286-4854, Vol. 96, nr 2, s. 27013-Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Based on the first-principle density functional calculations we predict that Li-doped graphane (prehydrogenated graphene) can be a potential candidate for hydrogen storage. The calculated Li-binding energy on graphane is significantly higher than the Li bulk's cohesive energy ruling out any possibility of cluster formations in the Li-doped graphane. Our study shows that even with very low concentration (5.56%) of Li doping, the Li-graphane sheet can achieve a reasonable hydrogen storage capacity of 3.23 wt.%. The van der Waals corrected H(2) binding energies fall within the range of 0.12-0.29 eV, suitable for practical H(2) storage applications. 

    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-161557 (URN)10.1209/0295-5075/96/27013 (DOI)000295974600036 ()
    Tilgjengelig fra: 2011-11-20 Laget: 2011-11-15 Sist oppdatert: 2017-12-08bibliografisk kontrollert
    6. Calcium doped graphane as a hydrogen storage material
    Åpne denne publikasjonen i ny fane eller vindu >>Calcium doped graphane as a hydrogen storage material
    Vise andre…
    2012 (engelsk)Inngår i: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 100, nr 18, s. 183902-Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    On the basis of first principle density functional theory, we have studied the stability, electronic structure, and hydrogen storage capacity of a monolayer calcium doped graphane (CHCa). The stability of CHCa was further investigated using the ab initio molecular dynamics study. The binding energy of Ca on graphane sheet was found to be higher than its bulk cohesive energy, which indicates the stability of CHCa. It was observed that with a doping concentration of 11.11% of Ca on graphane sheet, a reasonably good H-2 storage capacity of 6 wt. % could be attained. The adsorption energies of H-2 were found to be 0.1 eV, within the range of practical H-2 storage applications.

    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-174925 (URN)10.1063/1.4710526 (DOI)000303598600068 ()
    Tilgjengelig fra: 2012-05-30 Laget: 2012-05-30 Sist oppdatert: 2017-12-07bibliografisk kontrollert
    7. Strain induced lithium functionalized graphane as a high capacity hydrogen storage material
    Åpne denne publikasjonen i ny fane eller vindu >>Strain induced lithium functionalized graphane as a high capacity hydrogen storage material
    2012 (engelsk)Inngår i: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 101, nr 10, s. 103907-Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Strain effects on the stability, electronic structure, and hydrogen storage capacity of lithium-doped graphane have been investigated by state-of-the-art first principles density functional theory. Molecular dynamics simulations have confirmed the stability of Li on graphane sheet when it is subject to 10% of tensile strain. Under biaxial asymmetric strain, the binding energy of Li of graphane (CH) sheet increases by 52% with respect to its bulk's cohesive energy. With 25% doping concentration of Li on CH sheet, the gravimetric density of hydrogen storage is found to reach up to 12.12wt. %. The adsorption energies of H-2 are found to be within the range of practical H-2 storage applications. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4751249]

    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-183760 (URN)10.1063/1.4751249 (DOI)000309072800091 ()
    Tilgjengelig fra: 2012-11-05 Laget: 2012-11-01 Sist oppdatert: 2017-12-07bibliografisk kontrollert
    8. Metal Functionalized Silicene for Efficient Hydrogen Storage
    Åpne denne publikasjonen i ny fane eller vindu >>Metal Functionalized Silicene for Efficient Hydrogen Storage
    2013 (engelsk)Inngår i: ChemPhysChem, ISSN 1439-4235, E-ISSN 1439-7641, Vol. 14, nr 15, s. 3463-3466Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    First-principles calculations based on density functional theory are used to investigate the electronic structure along with the stability, bonding mechanism, band gap, and charge transfer of metal-functionalized silicene to envisage its hydrogen-storage capacity. Various metal atoms including Li, Na, K, Be, Mg, and Ca are doped into the most stable configuration of silicene. The corresponding binding energies and charge-transfer mechanisms are discussed from the perspective of hydrogen-storage compatibility. The Li and Na metal dopants are found to be ideally suitable, not only for strong metal-to-substrate binding and uniform distribution over the substrate, but also for the high-capacity storage of hydrogen. The stabilities of both Li- and Na-functionalized silicene are also confirmed through molecular dynamics simulations. It is found that both of the alkali metals, Li+ and Na+, can adsorb five hydrogen molecules, attaining reasonably high storage capacities of 7.75 and 6.9 wt%, respectively, with average adsorption energies within the range suitable for practical hydrogen-storage applications.

    HSV kategori
    Forskningsprogram
    Fysik med inriktning mot atom- molekyl- och kondenserande materiens fysik
    Identifikatorer
    urn:nbn:se:uu:diva-206630 (URN)10.1002/cphc.201300548 (DOI)000328674000008 ()
    Tilgjengelig fra: 2013-09-02 Laget: 2013-09-02 Sist oppdatert: 2017-12-06bibliografisk kontrollert
    9. Functionalization of hydrogenated silicene with alkali and alkaline earth metals for efficient hydrogen storage
    Åpne denne publikasjonen i ny fane eller vindu >>Functionalization of hydrogenated silicene with alkali and alkaline earth metals for efficient hydrogen storage
    2013 (engelsk)Inngår i: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 15, nr 43, s. 18900-18905Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    First principles density functional theory has been employed to investigate the electronic structure along with the stability, bonding mechanism, band gap and charge transfer of metal functionalized hydrogenated silicene (SiH), or silicane, in order to envisage the hydrogen storage capacity. Various metal adatoms including Li, Na, K, Be, Mg and Ca have been doped on the most stable chair like configuration of silicane. The corresponding binding energies and charge transfer mechanism have been discussed from the perspective of H-2 storage ability. The Li and Na metal adatoms have been found to be ideally suitable not only for their strong metal to substrate binding and uniform distribution over the substrate but also for their high capacity for storage of hydrogen. The stability of both Li and Na functionalized SiH has also been confirmed by MD simulations. It was found that both Li+ and Na+ adsorbed four H-2 molecules attaining reasonably high storage capacities of 6.30 wt% and 5.40 wt% respectively with average adsorption energies lying within the range suitable for practical H-2 storage applications, in contrast with alkaline earth metals.

    Emneord
    Silicane, Hydrogen Storage, Adsorption Energy
    HSV kategori
    Forskningsprogram
    Fysik med inriktning mot atom- molekyl- och kondenserande materiens fysik
    Identifikatorer
    urn:nbn:se:uu:diva-206631 (URN)10.1039/c3cp52830h (DOI)000325943200017 ()
    Tilgjengelig fra: 2013-09-02 Laget: 2013-09-02 Sist oppdatert: 2017-12-06bibliografisk kontrollert
    10. Polylithiated (OLi2) functionalized graphane as a potential hydrogen storage material
    Åpne denne publikasjonen i ny fane eller vindu >>Polylithiated (OLi2) functionalized graphane as a potential hydrogen storage material
    2012 (engelsk)Inngår i: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 101, nr 24, s. 243902-Artikkel i tidsskrift, Letter (Fagfellevurdert) Published
    Abstract [en]

    Hydrogen storage capacity, stability, bonding mechanism, and the electronic structure ofpolylithiated molecules (OLi2) functionalized graphane (CH) has been studied by means of firstprinciple DFT. Molecular dynamics have confirmed the stability, while Bader charge analysisdescribes the bonding mechanism of OLi2 with CH. The binding energy of OLi2on CH sheet hasbeen found to be large enough to ensure its uniform distribution without any clustering. It has beenfound that each OLi2 unit can adsorb up to six H2 molecules resulting into a storage capacity of12.90 wt. % with adsorption energies within the range of practical H2storage application.

    sted, utgiver, år, opplag, sider
    USA: , 2012
    Emneord
    Graphane, Polylithiated
    HSV kategori
    Forskningsprogram
    Fysik och astronomi med inriktning mot teoretisk fysik
    Identifikatorer
    urn:nbn:se:uu:diva-188884 (URN)10.1063/1.4772208 (DOI)000312490000108 ()
    Tilgjengelig fra: 2012-12-20 Laget: 2012-12-20 Sist oppdatert: 2017-12-06bibliografisk kontrollert
    11. Functionalization of hydrogenated graphene by polylithiated species for efficient hydrogen storage
    Åpne denne publikasjonen i ny fane eller vindu >>Functionalization of hydrogenated graphene by polylithiated species for efficient hydrogen storage
    2014 (engelsk)Inngår i: International journal of hydrogen energy, ISSN 0360-3199, E-ISSN 1879-3487, Vol. 39, nr 6, s. 2560-2566Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    The hydrogen (H-2) storage capacity of defected graphane (CH) functionalized by polylithiated species CLi3 and CLi4 has been investigated by means of first-principles DFT calculations. The stability and electronic structures of these potential H-2 storage materials have also been studied. The binding of these lithium rich species (CLi3, CLi4) to the CH sheet has been found to be strong enough to avoid clustering. The nature of bonding in C-Li and C-C has been revealed by Bader charge analysis. It has been found that when both sides of CH sheet are functionalized by polylithiated species, a storage capacity of more than 13 wt % can be achieved with adsorption energies of H-2 in the range of 0.25 eV-0.35 eV, which is suitable for an efficient H-2 storage.

    sted, utgiver, år, opplag, sider
    Uppsala: , 2014
    HSV kategori
    Forskningsprogram
    Fysik med inriktning mot atom- molekyl- och kondenserande materiens fysik
    Identifikatorer
    urn:nbn:se:uu:diva-206635 (URN)10.1016/j.ijhydene.2013.11.083 (DOI)000331920100015 ()
    Tilgjengelig fra: 2013-09-02 Laget: 2013-09-02 Sist oppdatert: 2017-12-06bibliografisk kontrollert
    12. Hexagonal Boron Nitride Sheet Decorated by Polylithiated Species for Efficient and Reversible Hydrogen Storage
    Åpne denne publikasjonen i ny fane eller vindu >>Hexagonal Boron Nitride Sheet Decorated by Polylithiated Species for Efficient and Reversible Hydrogen Storage
    2013 (engelsk)Inngår i: Science of Advanced Materials, ISSN 1947-2935, Vol. 5, nr 12, s. 1960-1966Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

     In the quest for promising hydrogen storage materials, we have performed first principles calculations on CLi3  and OLi2  decorated hexagonal boron nitride (h -BN), sheet. The strong binding of the polylithiated species to pristine and doped BN sheet and the large distance between these functionalized species ensure their uniform distribution over the sheet without being clustered. MD simulations have also confirmed the stabilities of both functionalized systems. Bader analysis and density of states reveals the bonding nature in the systems. A reasonably high H2  storage capacity with the adsorption energies within the desired window suggests that these systems hold promise as efficient H2  storage mediums.

    sted, utgiver, år, opplag, sider
    Uppsala: , 2013
    Emneord
    Polylithiated, Functionalization, Storage Capacity
    HSV kategori
    Forskningsprogram
    Fysik med inriktning mot atom- molekyl- och kondenserande materiens fysik
    Identifikatorer
    urn:nbn:se:uu:diva-206628 (URN)10.1166/sam.2013.1663 (DOI)000328005200020 ()
    Tilgjengelig fra: 2013-09-02 Laget: 2013-09-02 Sist oppdatert: 2014-01-23bibliografisk kontrollert
    13. Hydrogen storage in polylithiated BC3 monolayer sheet
    Åpne denne publikasjonen i ny fane eller vindu >>Hydrogen storage in polylithiated BC3 monolayer sheet
    2013 (engelsk)Inngår i: Solid State Communications, ISSN 0038-1098, E-ISSN 1879-2766, Vol. 170, s. 39-43Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    We perform a detailed study on the stability, electronic structure and hydrogen storage capacity of polylithiated (CLi3 functionalized) boron carbide (BC3) monolayer sheet using first-principles calculations. The binding of the CLi3 radical to the boron carbide (BC3) monolayer sheet is found to be large enough to ensure its uniform distribution without any clustering. The structural stability has been confirmed by molecular dynamics. Each lithium atom is able to accommodate 4 H2 molecules with an average binding energy of 0.21 eV, which is suitable for reversible H2 adsorption/desorption at ambient temperatures. The uptake of H2 is found to reach up to 9.83 wt% in polylithiated BC3 monolayer sheet.

    sted, utgiver, år, opplag, sider
    Uppsala: , 2013
    Emneord
    Nanosheet, Hydrogen storage, Polylithiation
    HSV kategori
    Forskningsprogram
    Fysik med inriktning mot atom- molekyl- och kondenserande materiens fysik
    Identifikatorer
    urn:nbn:se:uu:diva-206627 (URN)10.1016/j.ssc.2013.07.016 (DOI)000325594500009 ()
    Tilgjengelig fra: 2013-09-02 Laget: 2013-09-02 Sist oppdatert: 2017-12-06bibliografisk kontrollert
  • 2.
    Hussain, Tanveer
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Chakraborty, Sudip
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Ahuja, Rajeev
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori. Department of Materials and Engineering, Royal Institute of Technology (KTH).
    Metal Functionalized Silicene for Efficient Hydrogen Storage2013Inngår i: ChemPhysChem, ISSN 1439-4235, E-ISSN 1439-7641, Vol. 14, nr 15, s. 3463-3466Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    First-principles calculations based on density functional theory are used to investigate the electronic structure along with the stability, bonding mechanism, band gap, and charge transfer of metal-functionalized silicene to envisage its hydrogen-storage capacity. Various metal atoms including Li, Na, K, Be, Mg, and Ca are doped into the most stable configuration of silicene. The corresponding binding energies and charge-transfer mechanisms are discussed from the perspective of hydrogen-storage compatibility. The Li and Na metal dopants are found to be ideally suitable, not only for strong metal-to-substrate binding and uniform distribution over the substrate, but also for the high-capacity storage of hydrogen. The stabilities of both Li- and Na-functionalized silicene are also confirmed through molecular dynamics simulations. It is found that both of the alkali metals, Li+ and Na+, can adsorb five hydrogen molecules, attaining reasonably high storage capacities of 7.75 and 6.9 wt%, respectively, with average adsorption energies within the range suitable for practical hydrogen-storage applications.

  • 3.
    Hussain, Tanveer
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Chakraborty, Sudip
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    De Sarkar, Abir
    Johansson, Börje
    Ahuja, Rajeev
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Enhancement of energy storage capacity of Mg functionalized silicene and silicane under external strain2014Inngår i: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 105, nr 12, s. 123903-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The electronic structure, stability, and hydrogen storage capacity of strain induced Mg functionalized silicene (SiMg) and silicane (SiHMg) monolayers have been studied by means of van der Waals induced first principles calculations. A drastic increase in the binding energy of Mg adatoms on both the monolayers under the biaxial symmetric strain of 10% ensures the uniform distribution of dopants over the substrates. A significant positive charge on each Mg accumulates a maximum of six H-2 molecules with H-2 storage capacity of 8.10% and 7.95% in case of SiMg and SiHMg, respectively. The average adsorption energy for H-2 molecules has been found ideal for practical H-2 storage materials.

  • 4.
    Hussain, Tanveer
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Chakraborty, Sudip
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Kang, T. W.
    Johansson, Borje
    Ahuja, Rajeev
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    BC3 Sheet Functionalized with Lithium-Rich Species Emerging as a Reversible Hydrogen Storage Material2015Inngår i: ChemPhysChem, ISSN 1439-4235, E-ISSN 1439-7641, Vol. 16, nr 3, s. 634-639Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The decoration of a BC3 monolayer with the polylithiated molecules CLi4 and OLi2 has been extensively investigated to study the hydrogen-storage efficiency of the materials by first principles electronic structure calculations. The binding energies of both lithiated species with the BC3 substrate are much higher than their respective cohesive energies, which confirms the stability of the doped systems. A significant positive charge on the Li atom in each of the dopants facilitates the adsorption of multiple H-2 molecules under the influence of electrostatic and van der Waals interactions. We observe a high H-2-storage capacity of 11.88 and 8.70 wt% for the BC3-CLi4 and BC3-OLi2 systems, respectively, making them promising candidates as efficient energy-storage systems.

  • 5.
    Hussain, Tanveer
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    De Sarkar, Abir
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Ahuja, Rajeev
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Strain induced lithium functionalized graphane as a high capacity hydrogen storage material2012Inngår i: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 101, nr 10, s. 103907-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Strain effects on the stability, electronic structure, and hydrogen storage capacity of lithium-doped graphane have been investigated by state-of-the-art first principles density functional theory. Molecular dynamics simulations have confirmed the stability of Li on graphane sheet when it is subject to 10% of tensile strain. Under biaxial asymmetric strain, the binding energy of Li of graphane (CH) sheet increases by 52% with respect to its bulk's cohesive energy. With 25% doping concentration of Li on CH sheet, the gravimetric density of hydrogen storage is found to reach up to 12.12wt. %. The adsorption energies of H-2 are found to be within the range of practical H-2 storage applications. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4751249]

  • 6.
    Hussain, Tanveer
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    De Sarkar, Abir
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Maark, Tuhina Adit
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Sun, Weiwei
    Ahuja, Rajeev
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Strain and doping effects on the energetics of hydrogen desorption from the MgH2 (001) surface2013Inngår i: Europhysics letters, ISSN 0295-5075, E-ISSN 1286-4854, Vol. 101, nr 2, s. 27006-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    On the basis of first-principles calculations we have systematically investigated the energetics of hydrogen desorption from the MgH2 (001) surface. Based on total energy and electronic structure calculations, two modes namely strain and doping of selected dopants (Al, Si, Ti) and the combined effect of both on the dehydrogenation energies (Delta H) of MgH2 (001) systems have been analyzed. The maximum improvement in Delta H has been obtained with the combined effect of doping and strain. Among all the dopants, Al gives the lowest value of Delta H when the system Al-MgH2 is subjected to a 7.5% biaxial symmetric strain whereas the Si-MgH2 systems show the least improvement in Delta H. The doping of Ti on MgH2 (001) is also very beneficial even without strain. The reduction in Delta H is caused by the charge localization on the metal atoms, destabilization and the weakening of metal-hydrogen bonds.

  • 7.
    Hussain, Tanveer
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Islam, Muhammed Shafiqul
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Rao, G. S.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Panigrahi, Puspamitra
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Gupta, D.
    Ahuja, Rajeev
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Hydrogen storage properties of light metal adatoms (Li, Na) decorated fluorographene monolayer2015Inngår i: Nanotechnology, ISSN 0957-4484, E-ISSN 1361-6528, Vol. 26, nr 27, artikkel-id 275401Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Owing to its high energy density, the potential of hydrogen (H-2) as an energy carrier has been immense, however its storage remains a big obstacle and calls for an efficient storage medium. By means of density functional theory (DFT) in spin polarized generalized gradient approximation (GGA), we have investigated the structural, electronic and hydrogen storage properties of a light alkali metal (Li, Na) functionalized fluorographene monolayer (FG). Metal adatoms bind to the FG with significantly high binding energy, much higher than their cohesive energies, which helps to achieve a uniform distribution of metal adatoms on the monolayer and consequently ensure reversibility. Due to a difference of electronegativities, each metal adatom transfers a substantial amount of its charge to the FG monolayer and attains a partial positive state, which facilitates the adsorption of multiple H-2 molecules around the adatoms by electrostatic as well as van der Waals interactions. To get a better description of H-2 adsorption energies with metal-doped systems, we have also performed calculations using van der Waals corrections. For both the functionalized systems, the results indicate a reasonably high H-2 storage capacity with H2 adsorption energies falling into the range for the practical applications.

  • 8.
    Hussain, Tanveer
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Kaewmaraya, Thanayut
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Chakraborty, Sudip
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Ahuja, Rajeev
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori. Department of Materials and Engineering, Royal Institute of Technology (KTH).
    Functionalization of hydrogenated silicene with alkali and alkaline earth metals for efficient hydrogen storage2013Inngår i: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 15, nr 43, s. 18900-18905Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    First principles density functional theory has been employed to investigate the electronic structure along with the stability, bonding mechanism, band gap and charge transfer of metal functionalized hydrogenated silicene (SiH), or silicane, in order to envisage the hydrogen storage capacity. Various metal adatoms including Li, Na, K, Be, Mg and Ca have been doped on the most stable chair like configuration of silicane. The corresponding binding energies and charge transfer mechanism have been discussed from the perspective of H-2 storage ability. The Li and Na metal adatoms have been found to be ideally suitable not only for their strong metal to substrate binding and uniform distribution over the substrate but also for their high capacity for storage of hydrogen. The stability of both Li and Na functionalized SiH has also been confirmed by MD simulations. It was found that both Li+ and Na+ adsorbed four H-2 molecules attaining reasonably high storage capacities of 6.30 wt% and 5.40 wt% respectively with average adsorption energies lying within the range suitable for practical H-2 storage applications, in contrast with alkaline earth metals.

  • 9.
    Hussain, Tanveer
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Maark, Tuhina Adit
    Chakraborty, Sudip
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Ahuja, Rajeev
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Improvement in Hydrogen Desorption from - and -MgH2 upon Transition-Metal Doping2015Inngår i: ChemPhysChem, ISSN 1439-4235, E-ISSN 1439-7641, Vol. 16, nr 12, s. 2557-2561Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A thorough study of the structural, electronic, and hydrogen-desorption properties of - and -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 - and -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 - and -MgH2 and cause destabilization by weakening the MgH bonds. Our results show that doping with certain TMs can facilitate desorption of hydrogen from - and -MgH2 at much lower temperatures than from their pure forms. The hydrogen adsorption strengths are also studied by density-of-states analysis.

  • 10.
    Hussain, Tanveer
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Maark, Tuhina Adit
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    De Sarkar, Abir
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Ahuja, Rajeev
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Polylithiated (OLi2) functionalized graphane as a potential hydrogen storage material2012Inngår i: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 101, nr 24, s. 243902-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Hydrogen storage capacity, stability, bonding mechanism, and the electronic structure ofpolylithiated molecules (OLi2) functionalized graphane (CH) has been studied by means of firstprinciple DFT. Molecular dynamics have confirmed the stability, while Bader charge analysisdescribes the bonding mechanism of OLi2 with CH. The binding energy of OLi2on CH sheet hasbeen found to be large enough to ensure its uniform distribution without any clustering. It has beenfound that each OLi2 unit can adsorb up to six H2 molecules resulting into a storage capacity of12.90 wt. % with adsorption energies within the range of practical H2storage application.

  • 11.
    Hussain, Tanveer
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Maark, Tuhina Adit
    Pathak, Biswarup
    Ahuja, Rajeev
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Improvement in the hydrogen desorption from MgH2 upon transition metals doping: A hybrid density functional calculations2013Inngår i: AIP Advances, ISSN 2158-3226, E-ISSN 2158-3226, Vol. 3, nr 10, s. 102117-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This study deals with the investigations of structural, electronic and thermodynamic properties of MgH2 doped with selected transition metals (TMs) by means of hybrid density functional theory (PBE0). On the structural side, the calculated lattice parameters and equilibrium volumes increase in case of Sc, Zr and Y opposite to all the other dopants indicating volumetrically increased hydrogen density. Except Fe, all the dopants improve the kinetics of MgH2 by reducing the heat of adsorption with Cu, Nb, Ni and V proving more efficient than others studied TM's. The electronic properties have been studied by density of states and correlated with hydrogen adsorption energies. 

  • 12.
    Hussain, Tanveer
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Panigrahi, Puspamitra
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Ahuja, Rajeev
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Enriching physisorption of H2S and NH3 gases on a graphane sheet by doping with Li adatoms2014Inngår i: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 16, nr 17, s. 8100-8105Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We have used density functional theory to investigate the adsorption efficiency of a hydrogenated graphene (graphane) sheet for H2S and NH3 gases. We find that neither the pristine graphane sheet nor the sheet defected by removing a few surface H atoms have sufficient affinity for either H2S or NH3 gas molecules. However, a graphane sheet doped with Li adatoms shows a strong sensing affinity for both the mentioned gas molecules. We have calculated the absorption energies with one [referred to as half coverage] molecule and two molecules [referred to as full coverage] for both gases with the Li-doped graphane sheet. We find that for both the gases, the calculated absorption energies are adequate enough to decide that the Li-doped graphane sheet is suitable for sensing H2S and NH3 gases. The Li-doped sheet shows a higher affinity for the NH3 gas compared to the H2S gas molecules due to a stronger Li(s)-N(p) hybridization compared to that of Li(s)-S(p). However, while going from the half coverage effect to the full coverage effect, the calculated binding energies show a decreasing trend for both the gases. The calculated work function of the Li-doped graphane sheet decreases while bringing the gas molecules within its vicinity, which explains the affinity of the sheet towards both the gas molecules.

  • 13.
    Hussain, Tanveer
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Panigrahi, Puspamitra
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Ahuja, Rajeev
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Sensing propensity of a defected graphane sheet towards CO, H2O and NO22014Inngår i: Nanotechnology, ISSN 0957-4484, E-ISSN 1361-6528, Vol. 25, nr 32, s. 325501-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We have used density functional theory to investigate the sensing property of a hydrogenated graphene sheet (graphane) towards CO, H2O and NO2 gas molecules. Though the pristine graphane sheet is found not to have sufficient affinity towards the mentioned gas molecules, the defected sheet (removing few surface H atoms) has a strong affinity towards the gas molecules. While CO and H2O are found to be weakly physisorbed, the NO2 molecules are found to be strongly chemi-sorbed to the defected graphane sheet. With NO2, the N(p) and O(p) states are found to have strong hybridization with the most active C(p) states which lie at the defected site of the graphane sheet. While increasing the coverage effect of the mentioned gas molecules toward the defected sheet, the adsorption energies do not change significantly. At the same time, the work function of the defected graphane sheet shows an increasing trend while adsorbed with CO, H2O and NO2 gas molecules, opening up the possibilities for a future gas sensor.

  • 14.
    Hussain, Tanveer
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Pathak, Biswarup
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Maark, Tuhina Adit
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Araujo, Carlos Moyses
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Scheicher, Ralph H.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Ahuja, Rajeev
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Ab initio study of lithium-doped graphane for hydrogen storage2011Inngår i: Europhysics letters, ISSN 0295-5075, E-ISSN 1286-4854, Vol. 96, nr 2, s. 27013-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Based on the first-principle density functional calculations we predict that Li-doped graphane (prehydrogenated graphene) can be a potential candidate for hydrogen storage. The calculated Li-binding energy on graphane is significantly higher than the Li bulk's cohesive energy ruling out any possibility of cluster formations in the Li-doped graphane. Our study shows that even with very low concentration (5.56%) of Li doping, the Li-graphane sheet can achieve a reasonable hydrogen storage capacity of 3.23 wt.%. The van der Waals corrected H(2) binding energies fall within the range of 0.12-0.29 eV, suitable for practical H(2) storage applications. 

  • 15.
    Hussain, Tanveer
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Pathak, Biswarup
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Maark, Tuhina Adit
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Ramzan, Muhammad
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Ahuja, Rajeev
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Functionalization of graphane with alkali and alkaline-earth metals: An insulator-to-metallic transition2012Inngår i: Europhysics letters, ISSN 0295-5075, E-ISSN 1286-4854, Vol. 99, nr 4, s. 47004-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In view of interest in functionalized carbon nanostructures due to their potential applications in nanotechnology and nanoelectronics, we have performed a systematic and thorough density functional theory (DFT) study on the interaction of the elements in the first two groups of the periodic table with graphane (hydrogenated graphene) sheet. GGA approximation as employed in DFT has been used to study in detail the binding configuration, bond length, charge transfer and band gap of each of these adatoms doped graphane (CH) systems. To have a better understanding of the adatoms-CH interaction, different doping concentrations varying from 3.125% to 50% have been considered. A certain trend in binding strength, bond length and charge transfer has been found in the case of both alkali metal and alkaline-earth metal adatoms. In the case of alkali-metal adatoms at the low doping concentration of 3.125%, semiconductor behavior was found, whereas at doping higher than this the compound showed metallic behavior. In contrast, alkaline-earth metal-doped CH exhibited metallic behavior at all the doping concentrations. Copyright (C) EPLA, 2012

  • 16.
    Hussain, Tanveer
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Pathak, Biswarup
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Ramzan, Muhammad
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Maark, Tuhina Adit
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Ahuja, Rajeev
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Calcium doped graphane as a hydrogen storage material2012Inngår i: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 100, nr 18, s. 183902-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    On the basis of first principle density functional theory, we have studied the stability, electronic structure, and hydrogen storage capacity of a monolayer calcium doped graphane (CHCa). The stability of CHCa was further investigated using the ab initio molecular dynamics study. The binding energy of Ca on graphane sheet was found to be higher than its bulk cohesive energy, which indicates the stability of CHCa. It was observed that with a doping concentration of 11.11% of Ca on graphane sheet, a reasonably good H-2 storage capacity of 6 wt. % could be attained. The adsorption energies of H-2 were found to be 0.1 eV, within the range of practical H-2 storage applications.

  • 17.
    Hussain, Tanveer
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Sarkar, Abir De
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori. Department of Physics, Central University of Rajasthan,.
    Ahuja, Rajeev
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori. Department of Materials and Engineering, Royal Institute of Technology (KTH).
    Functionalization of hydrogenated graphene by polylithiated species for efficient hydrogen storage2014Inngår i: International journal of hydrogen energy, ISSN 0360-3199, E-ISSN 1879-3487, Vol. 39, nr 6, s. 2560-2566Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The hydrogen (H-2) storage capacity of defected graphane (CH) functionalized by polylithiated species CLi3 and CLi4 has been investigated by means of first-principles DFT calculations. The stability and electronic structures of these potential H-2 storage materials have also been studied. The binding of these lithium rich species (CLi3, CLi4) to the CH sheet has been found to be strong enough to avoid clustering. The nature of bonding in C-Li and C-C has been revealed by Bader charge analysis. It has been found that when both sides of CH sheet are functionalized by polylithiated species, a storage capacity of more than 13 wt % can be achieved with adsorption energies of H-2 in the range of 0.25 eV-0.35 eV, which is suitable for an efficient H-2 storage.

  • 18.
    Hussain, Tanveer
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Sarkar, Abir De
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Kang, Tae Won
    Dongguk University.
    Ahuja, Rajeev
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori. Department of Materials and Engineering, Royal Institute of Technology (KTH).
    Hexagonal Boron Nitride Sheet Decorated by Polylithiated Species for Efficient and Reversible Hydrogen Storage2013Inngår i: Science of Advanced Materials, ISSN 1947-2935, Vol. 5, nr 12, s. 1960-1966Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

     In the quest for promising hydrogen storage materials, we have performed first principles calculations on CLi3  and OLi2  decorated hexagonal boron nitride (h -BN), sheet. The strong binding of the polylithiated species to pristine and doped BN sheet and the large distance between these functionalized species ensure their uniform distribution over the sheet without being clustered. MD simulations have also confirmed the stabilities of both functionalized systems. Bader analysis and density of states reveals the bonding nature in the systems. A reasonably high H2  storage capacity with the adsorption energies within the desired window suggests that these systems hold promise as efficient H2  storage mediums.

  • 19.
    Islam, Muhammed Shafiqul
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Hussain, Tanveer
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori. Royal Inst Technol KTH, Dept Mat & Engn, Appl Mat Phys, S-10044 Stockholm, Sweden.;Univ Queensland, Australian Inst Bioengn & Nanotechnol, Ctr Theoret & Computat Mol Sci, Brisbane, Qld 4072, Australia..
    Rao, G. S.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Panigrahi, P.
    Hindustan Univ, Clean Energy & Nano Convergence Ctr, Madras, Tamil Nadu, India..
    Ahuja, Rajeev
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori. Royal Inst Technol KTH, Dept Mat & Engn, Appl Mat Phys, S-10044 Stockholm, Sweden..
    Augmenting the sensing aptitude of hydrogenated graphene by crafting with defects and dopants2016Inngår i: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 228, s. 317-321Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Density functional theory (DFT) level calculations were performed to study the interaction of hydrogenated graphene (CH) monolayer towards methane (CH4) gas molecules. The structural, electronic and gas sensing properties of pure, defected and light metal-doped CH monolayer were investigated. For the pristine CH, the estimated binding energy of CH4 fell short of the desired physisorption range and limit its gas sensing application at ambient conditions. However, upon crafting defects on pure CH layer by introducing hydrogen vacancies, a sharp increase in adsorption energies were observed when the CH4 molecules approached the defected sites of CH. Further, the effect of metal doping was studied by uniformly distributing light metal adatoms on CH monolayer which significantly enhanced the CH4 adsorption. To have better accuracy in calculating adsorption energies, we have incorporated van der Waals type corrections to our calculations for these weakly interacting systems.

  • 20.
    Li, Yunguo
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Hussain, Tanveer
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Sarkar, Abir De
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Ahuja, Rajeev
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Hydrogen storage in polylithiated BC3 monolayer sheet2013Inngår i: Solid State Communications, ISSN 0038-1098, E-ISSN 1879-2766, Vol. 170, s. 39-43Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We perform a detailed study on the stability, electronic structure and hydrogen storage capacity of polylithiated (CLi3 functionalized) boron carbide (BC3) monolayer sheet using first-principles calculations. The binding of the CLi3 radical to the boron carbide (BC3) monolayer sheet is found to be large enough to ensure its uniform distribution without any clustering. The structural stability has been confirmed by molecular dynamics. Each lithium atom is able to accommodate 4 H2 molecules with an average binding energy of 0.21 eV, which is suitable for reversible H2 adsorption/desorption at ambient temperatures. The uptake of H2 is found to reach up to 9.83 wt% in polylithiated BC3 monolayer sheet.

  • 21.
    Maark, Tuhina Adit
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Hussain, Tanveer
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Ahuja, Rajeev
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Structural, electronic and thermodynamic properties of Al- and Si-doped alpha-, gamma-, and beta-MgH2: Density functional and hybrid density functional calculations2012Inngår i: International journal of hydrogen energy, ISSN 0360-3199, E-ISSN 1879-3487, Vol. 37, nr 11, s. 9112-9122Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this work, we present a detailed study of Al- and Si-doped alpha-, gamma-, and beta-MgH2 phases using the gradient corrected density functional GGA-PBE and the hybrid Hartree-Fock density functionals PBE0 and HSE06 within the framework of generalized Kohn-Sham density functional theory (DFT) using a plane-wave basis set. We investigate the structural, electronic, and thermodynamical properties of these compounds with regard to their hydrogen storage effectiveness. PBE0 and HSE06 predict cell parameters and bond lengths that are in good agreement with the GGA-PBE calculations and previously known experimental results. As expected smaller band gaps (E(g)s) are predicted by GGA-PBE for the pure magnesium hydride phases. PBE0 overcomes the deficiencies of DFT in treating these materials better than HSE06 and yields E(g)s that compare even better with previous GW calculations. Both the hybrid functionals increase the E(g)s of the Al-doped magnesium hydrides by much less magnitudes than of the Si-doped phases. This difference is interpreted in terms of charge density distributions. Best H-2 adsorption energies (Delta H-ads) are computed by HSE06 while GGA-PBE significantly overestimates them. Si-doped alpha- and beta-MgH2 exhibited the least negative Delta H-ads in close proximity to the H-2 binding energy range of -0.21 to -0.41 eV ideal for practical H-2 storage transportation applications.

  • 22.
    Mahabal, Manasi S.
    et al.
    HPT Arts & RYK Sci Coll, Dept Phys, Nasik 422005, Maharashtra, India..
    Deshpande, Mrinalini D.
    HPT Arts & RYK Sci Coll, Dept Phys, Nasik 422005, Maharashtra, India..
    Hussain, Tanveer
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori. Royal Inst Technol KTH, Dept Mat & Engn, Appl Mat Phys, S-10044 Stockholm, Sweden.;Univ Queensland, Australian Inst Bioengn & Nanotechnol, Ctr Theoret & Computat Mol Sci, Brisbane, Qld 4072, Australia..
    Ahuja, Rajeev
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori. Royal Inst Technol KTH, Dept Mat & Engn, Appl Mat Phys, S-10044 Stockholm, Sweden..
    Sensing Characteristics of a Graphene-like Boron Carbide Monolayer towards Selected Toxic Gases2015Inngår i: ChemPhysChem, ISSN 1439-4235, E-ISSN 1439-7641, Vol. 16, nr 16, s. 3511-3517Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    By using first-principles calculations based on density functional theory, we study the adsorption efficiency of a BC3 sheet for various gases, such as CO, CO2, NO, NO2, and NH3. The optimal adsorption position and orientation of these gas molecules on the BC3 surface is determined and the adsorption energies are calculated. Among the gas molecules, CO2 is predicted to be weakly adsorbed on the graphene-like BC3 sheet, whereas the NH3 gas molecule shows a strong interaction with the BC3 sheet. The charge transfer between the molecules and the sheet is discussed in terms of Bader charge analysis and density of states. The calculated work function of BC3 in the presence of CO, CO2, and NO is greater than that of a bare BC3 sheet. The decrease in the work function of BC3 sheets in the presence of NO2 and NH3 further explains the affinity of the sheet towards the gas molecules. The energy gap of the BC3 sheets is sensitive to the adsorption of the gas molecules, which implies possible future applications in gas sensors.

  • 23.
    Panigrahi, Puspamitra
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Araujo, Carlos Moyses Graca
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Hussain, Tanveer
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Ahuja, Rajeev
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Crafting ferromagnetism in Mn-doped MgO surfaces with p-type defects2014Inngår i: Science and Technology of Advanced Materials, ISSN 1468-6996, E-ISSN 1878-5514, Vol. 15, nr 3, s. 035008-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We have employed first-principles calculations based on density functional theory (DFT) to investigate the underlying physics of unusual magnetism in Mn-doped MgO surface. We have studied two distinct scenarios. In the first one, two Mn atoms are substitutionally added to the surface, occupying the Mg sites. Both are stabilized in the Mn3+ valence state carrying a local moment of 4.3 mu(B) having a high-spin configuration. The magnetic interaction between the local moments display a very short-ranged characteristic, decaying very quickly with distance, and having antiferromagnetic ordering lower in energy. The energetics analysis also indicates that the Mn ions prefer to stay close to each other with an oxygen atom bridging the local interaction. In the second scenario, we started exploring the effect of native defects on the magnetism by crafting both Mg and O vacancies, which are p-and n-type defects, respectively. It is found that the electrons and holes affect the magnetic interaction between Mn ions in a totally different manner. The n-type defect leads to very similar magnetism, with the AFM configuration being energetically preferred. However, in the presence of Mg vacancy, the situation is quite different. The Mn atoms are further oxidized, giving rise to mixed Mn(d) ionic states. As a consequence, the Mn atoms couple ferromagnetically, when placed in the close configuration, and the obtained electronic structure is coherent with the double-exchange type of magnetic interaction. To guarantee the robustness of our results, we have benchmarked our calculations with three distinct theory levels, namely DFT-GGA, DFT-GGA+U and DFT-hybrid functionals. On the surface, the Mg vacancy displays lower formation energy occurring at higher concentrations. Therefore, our model systems can be the basis to explain a number of controversial results regarding transition metal doped oxides.

  • 24.
    Panigrahi, Puspamitra
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Hussain, Tanveer
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Araujo, Carlos Moyses Graca
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Ahuja, Rajeev
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Hole induced Jahn Teller distortion ensuing ferromagnetism in Mn-MgO: bulk, surface and one dimensional structures2014Inngår i: Journal of Physics: Condensed Matter, ISSN 0953-8984, E-ISSN 1361-648X, Vol. 26, nr 26, s. 265801-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Using density functional theory, we investigate the magnetic properties of Mn doped MgO in its bulk (3D), surface (2D) and one dimensional (1D) structures. At a low dilute limit (1.5 %), the Mn impurity behaves indifferent to its position in 3D but energetically prefers to be on one of the surfaces of 2D and 1D structures. At a higher dilute limit (3.1 %), the Mn impurities stabilizing at Mn-d((3+)) ionic states prefer to be in a close configuration (4.2 angstrom compared to 5.95 angstrom) and the antiferromagnetic ordering (AFM) between them is preferred over the ferromagnetic ordering. The n-type extrinsic defects (O vacancy), when introduced to Mn doped MgO structures, also result in similar AFM exchanges as between the Mn impurities. However, the p-type defects (Mg vacancy) in the Mn doped MgO structures result in a reduced magnetic moment for the Mn atoms and bring a significant Jahn Teller (JT)-type of distortion to the e(g) and t(2)g degenerate states of Mn-d((3+)) ions. The strong hybridization between distorted Mnd states and O-2p states results in a FM exchange coupling between the Mn ions, in all the three mentioned Mn doped MgO structures. As we move from 3D to 2D, to 1D structures, the influence of JT distortion decreases, reflecting a decreasing trend for the strength of the FM exchange coupling between the Mn atoms.

  • 25.
    Pathak, Biswarup
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Pradhan, Kalpataru
    Hussain, Tanveer
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Ahuja, Rajeev
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Jena, Purusottam
    Functionalized Boranes for Hydrogen Storage2012Inngår i: ChemPhysChem, ISSN 1439-4235, E-ISSN 1439-7641, Vol. 13, nr 1, s. 300-304Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Using density functional theory, the generalized gradient approximation for the exchange-correlation potential and MollerPlesset perturbation theory we study the hydrogen uptake of Li- and Mg-doped boranes. Specifically, we calculate the structures and binding energies of hydrogen molecules sequentially attached to LiB6H7, LiB12H13, Li2B6H6, Li2B12H12, MgB6H6, and MgB12H12. Up to three H2 molecules can be bound quasi-molecularly to each of the metal cations with binding energies per H2 molecule ranging between 0.07 eV and 0.27 eV. The corresponding gravimetric densities lie in the range of 3.49 to 12 wt %, not counting the H atoms bound chemically to the B atoms.

  • 26.
    Ragupathi, V.
    et al.
    Hindustan Inst Technol & Sci, Ctr Clean Energy & Nano Convergence, Madras, Tamil Nadu, India..
    Safiq, M.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori. Royal Inst Technol KTH, Appl Mat Phys, Dept Mat, S-10044 Stockholm, Sweden.;Royal Inst Technol KTH, Appl Mat Phys, Dept Engn, S-10044 Stockholm, Sweden..
    Panigrahi, P.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori. Hindustan Inst Technol & Sci, Ctr Clean Energy & Nano Convergence, Madras, Tamil Nadu, India.
    Hussain, Tanveer
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori. Royal Inst Technol KTH, Appl Mat Phys, Dept Mat, S-10044 Stockholm, Sweden.;Royal Inst Technol KTH, Appl Mat Phys, Dept Engn, S-10044 Stockholm, Sweden..
    Raman, S.
    Hindustan Inst Technol & Sci, Ctr Clean Energy & Nano Convergence, Madras, Tamil Nadu, India..
    Ahuja, Rajeev
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori. Royal Inst Technol KTH, Appl Mat Phys, Dept Mat, S-10044 Stockholm, Sweden.;Royal Inst Technol KTH, Appl Mat Phys, Dept Engn, S-10044 Stockholm, Sweden..
    Nagarajan, G. S.
    Dongguk Univ, NITA, 26 Phildong3ga, Seoul 100715, South Korea..
    Enhanced electrochemical performance of LiMnBO3 with conductive glassy phase: a prospective cathode material for lithium-ion battery2017Inngår i: Ionics (Kiel), ISSN 0947-7047, E-ISSN 1862-0760, Vol. 23, nr 7, s. 1645-1653Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    LiMnBO3 has been identified as a promising cathode material for next-generation lithium-ion batteries. In this study, LiMnBO3 along with glassy lithium borate material (LiMnBO3 (II)) is synthesized by sol-gel method. X-ray diffraction (XRD) analysis depicts the existence of LiBO2 glassy phase along with m-LiMnBO3 phase. Transmission electron microscopy (TEM) analysis confirms the presence of LiBO2 glassy phase. An enhanced electrical conductivity of 3.64 x 10(-7) S/cm is observed for LiMnBO3 (II). The LiBO2 glassy phase is found to promote the Li reaction kinetics in LiMnBO3 (II). The synthesized LiMnBO3 (II) delivers a first discharge capacity of 310 mAh g(-1) within a potential window of 1.5-4.5 V at C/10 rate. Further, a discharge capacity of 186 mAh g(-1) at the 27th cycle shows a better cycle performance. The enhanced capacity is due to the presence of LiBO2 glassy phase and more than one Li-ion transfer in the lithium-rich stoichiometry of LiMnBO3 (II). Density functional theory calculation reveals the exact electronic structure of m-LiMnBO3 with a band gap of 3.05 eV. A charge transfer mechanism is predicted for delithiation process of m-LiMnBO3.

  • 27.
    Ramzan, Muhammad
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Hussain, Tanveer
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Ahuja, Rajeev
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    High pressure phase determination and electronic properties of lithiumamidoborane2012Inngår i: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 101, nr 11, s. 111902-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this study we report on the high pressure phase of the promising hydrogen storage material lithiumamidoborane (LiNH2BH3), on the basis of density functional theory calculations with generalized gradient approximation. We take the five possible candidate structures, Pbca, Pbcn, Pcca, Pnma, and Pnnm for the high pressure study of LiNH2BH3. The corresponding structures are relaxed with respect to fractional atomic coordinates and cell parameters, with the use of fully self-consistent ab initio electronic structure calculations to get the equilibrium parameters and total enemies. Then we compare the energies of these phases and find that Pbcn is the most favorable phase at approximate to 100 GPa. Then we calculate the structural parameters of this phase. Finally, we calculate the density of states, Bader charge analysis, and corresponding electron density of this phase.

  • 28.
    Ramzan, Muhammad
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap.
    Hussain, Tanveer
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap.
    Ahuja, Rajeev
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap.
    Hydrogen diffusion in bulk and nanoclusters of MgH2 and the role of catalysts on the basis of ab initio molecular dynamics2009Inngår i: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 94, nr 22, s. 221910-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We present ab initio molecular dynamics calculations based on density functional theory to study the hydrogen-deuterium exchange in bulk and nanoclusters of MgH2. Our calculations reveal the important role of catalysts to diffuse the hydrogen at low temperatures and increase the diffusion rate. We determine the diffusion constants, < D > of deuterium, and show the single hydrogen-deuterium exchange in bulk and nanocluster of MgH2. Our calculated value of diffusion constant of deuterium in bulk MgH2 is in excellent agreement with the experimental value. Furthermore, we show the edge site importance of catalysts in the fast diffusion of hydrogen.

  • 29.
    Rao, G. S.
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori. Indian Inst Technol, Dept Met Engn & Mat Sci, Bombay 400076, Maharashtra, India..
    Hussain, Tanveer
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori. Royal Inst Technol KTH, Dept Mat & Engn, Appl Mat Phys, S-10044 Stockholm, Sweden.;Univ Queensland, Australian Inst Bioengn & Nanotechnol, Ctr Theoret & Computat Mol Sci, Brisbane, Qld 4072, Australia..
    Islam, Muhammed Shafiqul
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Sagynbaeva, M.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Gupta, D.
    Indian Inst Technol, Dept Met Engn & Mat Sci, Bombay 400076, Maharashtra, India..
    Panigrahi, P.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori. Hindustan Univ, Clean Energy & Nano Convergence Ctr, Madras, Tamil Nadu, India..
    Ahuja, Rajeev
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori. Royal Inst Technol KTH, Dept Mat & Engn, Appl Mat Phys, S-10044 Stockholm, Sweden..
    Adsorption mechanism of graphene-like ZnO monolayer towards CO2 molecules: enhanced CO2 capture2016Inngår i: Nanotechnology, ISSN 0957-4484, E-ISSN 1361-6528, Vol. 27, nr 1, artikkel-id 015502Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This work aims to efficiently capture CO2 on two-dimensional (2D) nanostructures for effective cleaning of our atmosphere and purification of exhausts coming from fuel engines. Here, we have performed extensive first principles calculations based on density functional theory (DFT) to investigate the interaction of CO2 on a recently synthesized ZnO monolayer (ZnO-ML) in its pure, defected and functionalized form. A series of rigorous calculations yielded the most preferential binding configurations of the CO2 gas molecule on a ZnO-ML. It is observed that the substitution of one oxygen atom with boron, carbon and nitrogen on the ZnO monolayer resulted into enhanced CO2 adsorption. Our calculations show an enriched adsorption of CO2 on the ZnO-ML when substituting with foreign atoms like B, C and N. The improved adsorption energy of CO2 on ZnO suggests the ZnO-ML could be a promising candidate for future CO2 capture.

  • 30.
    Sagynbaeva, Myskal
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Hussain, Tanveer
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Panigrahi, Puspamitra
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Johansson, Börje
    Ahuja, Rajeev
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Complementing the adsorption energies of CO2, H2S and NO2 to h-BN sheets by doping with carbon2015Inngår i: Europhysics letters, ISSN 0295-5075, E-ISSN 1286-4854, Vol. 109, nr 5, artikkel-id 57008Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We predict the adsorption proficiency of hexagonal boron nitride (h-BN) sheets to toxic gas molecules like CO2, H2S and NO2 on the basis of first-principles density functional theory calculations. The computed energies predict the pristine h-BN sheet to have very little affinity towards the mentioned gas molecules. However, while doping C at the N site of the h-BN sheet brings a significant enhancement to the estimated adsorption energies, doping C at B site of the sheet is found to be energetically not so favorable. To have a higher coverage effect, the concentration of C doping on the h-BN sheet is further increased which resulted in upsurging the adsorption energies for the mentioned gas molecules. Among the three, CO2, H2S are found to be physisorbed to the C-doped h-BN sheets, where as the C-doped sheets are found to have strong affinity towards NO2 gas molecules.

  • 31.
    Sun, Weiwei
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Hussain, Tanveer
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    De Sarkar, Abir
    Maark, Tuhina Adit
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Luo, Wei
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Ahuja, Rajeev
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Improvement in the desorption of H-2 from the MgH2 (110) surface by means of doping and mechanical strain2014Inngår i: Computational materials science, ISSN 0927-0256, E-ISSN 1879-0801, Vol. 86, s. 165-169Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this letter, density functional theory has been employed to investigate the release or desorption of hydrogen from the MgH2 (1 1 0) surface. To improve upon the energetics for hydrogen desorption from this system, the effects of strain and doping by Al, Si, Ti have been explored. Both of these two effects have been found to be effective. The strain applied along the X direction induces more prominent effects than along the Y direction. Regarding the doping, the system doped with Al gives the most noticeable effect. The Si doped system shows the least improvement while the Ti doped system lies in between as compared to the other two. The combination of doping and strain effects is found to be more efficacious.

1 - 31 of 31
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