Actividades i-link

i-link Activities

Group Metting on-line (23rd March, 2021)

Attendants: Marta Hernández, Tomas González, Massimiliano Bartolomei, José Campos, Lukas Tiefenthaler, Florent Calvo, Nadine Halbserstad, Elizabeth Gruber, Paul Scheier, Siegfried Kollatzek, Eva María Zunzunegui.

Visits

University of Innsbruck (19th-24th September, 2021)

José Campos Martínez
Marta I. Hernández

CNRS- University of Toulouse (30th November, 4th December, 2021)

Marta I. Hernández
Massimiliano Bartolomei
Esther García-Arroyo

LCAR Seminar

Marta I. Hernández

“Microscopic processes for hydrogen chemisorbed on graphene: permeation and recombination”.

Hydrogenated graphene is of great interest in several different fields such as hydrogen technologies, astrochemistry, nuclear fusion, electronics and magnetism. Using large molecular prototypes of graphene, we have carried out density functional theory computations to study in detail two processes occurring in this system, namely, the permeation or flipping of chemisorbed hydrogen atoms through graphene and the recombination of these atoms (desorption leading to the formation of hydrogen molecules), which can be regarded as the subsequent step after permeation. Firstly, we will present a new mechanism for the flipping of chemisorbed hydrogen atoms1 or protons2 through a graphene layer (see figure), where we have found that the activation energies involved are of the order of recent experimental findings 3,4. In addition, we will show preliminary results on reaction paths and rate coefficients for the recombination of hydrogen and deuterium, which exhibit large isotopic substitution effects (due to zero-point energy and tunneling) in qualitative agreement with thermal desorption measurements5,6. We believe that these studies will help to rationalize the experimental results as well as to provide some clues about properties of hydrogenated graphene.

[1] M. Bartolomei, M. I. Hernández, J. Campos-Martínez, R. Hernández-Lamoneda, G. Giorgi, “Permeation of chemisorbed hydrogen through graphene: a flipping mechanism elucidated”, Carbon 2021, 178, 718
[2] M. Bartolomei, M. I. Hernández, J. Campos-Martínez, R. Hernández-Lamoneda, “Graphene multi-protonation: A cooperative mechanism for proton permeation”, Carbon 2019, 144, 724.
[3] S. Hu et al, “Proton transport through one-atom-thick crystals”, Nature 2014, 516, 227.
[4] P. Z. Sun et al, “Limits on gas impermeability of graphene”, Nature 2020, 579, 229
[5] T. Zecho et al, “Adsorption of hydrogen and deuterium atoms on the (0001) graphite surface”, J. Chem. Phys. 117, 8486 (2002)
[6] L. Hornekaer et al, “Metastable structures and recombination pathways for atomic hydrogen on the graphite (0001) surface”, Phys. Rev. Lett. 96, 156104 (2006)

 

Theory Group Meeting Talks:

Massimiliano Bartolomei

“Ab initio results for H2 molecules adsorbed on Naphthalene doped with Na atoms”

Esther García-Arroyo

“Transmission of hydrogen isotopes through a graphdiyne layer”

 

links of interest

https://ec.europa.eu/research/mariecurieactions/

https://ec.europa.eu/research/mariecurieactions/calls/msca-doctoral-networks-2021