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Graphene based systems

Graphene displays very peculiar electronic and structural properties - strictly quantum chemical in nature - stemming from its symmetry and from carbon chemistry. On the other hand, their exploitation for designing practical devices requires large scale simulations (on the nano-to micro scale) [1]. The multi-scale serial approach is therefore applied[2], first to study basic properties at the QM level[3], which are then transferred into empirical FFs at the MM or coarser levels. We apply these concepts to the study of the interactions between hydrogen and graphene, in view of applications in the hydrogen storage and nano-electronics [4][5][6].

Graphene shows enhanced reactivity on defects [7] and convexities, which are therefore more prone to chemically adsorb hydrogen [8]. This given, we proposed an hydrogen storage device with loading/release mechanism based on the curvature manipulation, and proved its efficiency by means of Car-Parrinello simulations [9]. The dynamical curvature control could be obtained by means of coherent flexural phonons[10], which can also transport molecular hydrogen on macroscopic scales, as shown by means of atomistic MD simulations with Tersoff-like FFs. In addition, graphene gronw by Si evaporation on SiC is naturally rippled and DFT studies reveal multi-stabilty of rippling patterns, which could be exploited for curvature switching [11]. MuScaDe provides proprietary software specifically designed to implement the graphene multilayer plus hydrogen system with excited flexural phonons of given amplitude and wavelength (currently only for DL_POLY).

Fig 1: Simulation of rippled graphene with hydrogen. From top to bottom and left to right: DFT based calculations of naturally corrugated graphene on SiC substrate. The buffer layer and the first monolayer (with its electronic density, in orange) are distinguishable. On the right, the isolated and rippled graphene sheet, pristine and hydrogenated on the convexities (hydrogen atoms in orange). In the center, flexural phonons can detach hydrogen, and transport it in molecular form along the propagation direction, as shown by classical MD simulations with atomistic FFs (bottom).

 

Related Projects

GRAFLEX - a Marie Skłodowska Curie Action

 

References

  1. Valentina Tozzini, Vittorio Pellegrini - Prospects for hydrogen storage in graphene Physical Chemistry Chemical Physics 1:80- (2013)
  2. Vito Dario Camiola, Riccardo Farchioni, Tommaso Cavallucci, Antonio Rossi, Vittorio Pellegrini, Valentina Tozzini - Hydrogen Storage in Rippled Graphene: Perspectives from Multi-Scale Simulations Frontiers in Materials 2:00003 (2015)
  3. Antonio Rossi, Simone Piccinin, Vittorio Pellegrini, Stefano de Gironcoli, Valentina Tozzini - Nano-Scale Corrugations in Graphene: A Density Functional Theory Study of Structure, Electronic Properties and Hydrogenation The Journal of Physical Chemistry C 14:7900-7910 (2015)
  4. F. Bonaccorso, L. Colombo, G. Yu, M. Stoller, V. Tozzini, A. C. Ferrari, R. S. Ruoff, V. Pellegrini - Graphene, related two-dimensional crystals, and hybrid systems for energy conversion and storage Science 6217:1246501-1246501 (2015)
  5. Valentina Tozzini, Vittorio Pellegrini - Electronic structure and Peierls instability in graphene nanoribbons sculpted in graphane Physical Review B 81, 113404 (2010)
  6. Keisuke Takahashi, Shigehito Isobe, Kengo Omori, Torge Mashoff, Domenica Convertino, Vaidotas Miseikis, Camilla Coletti, Valentina Tozzini, Stefan Heun - Revealing the Multibonding State between Hydrogen and Graphene-Supported Ti Clusters The Journal of Physical Chemistry C 24:12974-12979 (2016)
  7. T. Mashoff, D. Convertino, V. Miseikis, C. Coletti, V. Piazza, V. Tozzini, F. Beltram, S. Heun - Increasing the active surface of titanium islands on graphene by nitrogen sputtering Applied Physics Letters 8:083901 (2015)
  8. Sarah Goler, Camilla Coletti, Valentina Tozzini, Vincenzo Piazza, Torge Mashoff, Fabio Beltram, Vittorio Pellegrini, Stefan Heun - Influence of Graphene Curvature on Hydrogen Adsorption: Toward Hydrogen Storage Devices The Journal of Physical Chemistry C 22:11506-11513 (2013)
  9. Valentina Tozzini, Vittorio Pellegrini - Reversible Hydrogen Storage by Controlled Buckling of Graphene Layers The Journal of Physical Chemistry C 51:25523-25528 (2011)
  10. Vito Dario Camiola, Riccardo Farchioni, Vittorio Pellegrini, Valentina Tozzini - Hydrogen transport within graphene multilayers by means of flexural phonons 2D Materials 1:014009 (2015)
  11. Tommaso Cavallucci, Valentina Tozzini - Multistable Rippling of Graphene on SiC: A Density Functional Theory Study The Journal of Physical Chemistry C 14:7670-7677 (2016)