Nanostructured architectures based on graphene/metal interfaces might be efficiently exploited in hydrogen storage due to the attractive capability to provide adsorption sites both at the top side of graphene and at the metal substrate after intercalation. We combined \textitin situ high resolution x-ray photoelectron spectroscopy and scanning tunneling microscopy with theoretical calculations to determine the arrangement of hydrogen atoms at the graphene/Ni(111) interface at room temperature. Our results show that at low coverage H atoms predominantly adsorb as monomers and that chemisorption saturates when ∽25% of the surface is hydrogenated. In parallel, with a much lower rate, H atoms intercalate below graphene and bind to Ni surface sites. Intercalation progressively destabilizes the C-H bonds and triggers the release of the hydrogen chemisorbed on graphene. Valence band and near edge absorption spectroscopy demonstrate that the Gr layer is fully lifted when the Ni surface is saturated with H. Thermal programmed desorption was used to determine the stability of the hydrogenated interface. Whereas the H atoms chemisorbed on graphene remain unperturbed over a wide temperature range, the intercalated phase abruptly desorbs 50-100 K above room temperature.
Dual-Route Hydrogenation of the Graphene/Ni Interface / D. Lizzit, M.I. Trioni, L. Bignardi, P. Lacovig, S. Lizzit, R. Martinazzo, R. Larciprete. - In: ACS NANO. - ISSN 1936-0851. - 13:2(2019 Feb), pp. 1828-1838.
|Titolo:||Dual-Route Hydrogenation of the Graphene/Ni Interface|
|Parole Chiave:||graphene; nickel; hydrogenation; storage; intercalation; desorption|
|Settore Scientifico Disciplinare:||Settore CHIM/02 - Chimica Fisica|
|Data di pubblicazione:||feb-2019|
|Data ahead of print / Data di stampa:||11-gen-2019|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1021/acsnano.8b07996|
|Appare nelle tipologie:||01 - Articolo su periodico|