2026-04-28T19:32:14Zhttps://uvadoc.uva.es/oai/request

oai:uvadoc.uva.es:10324/638562024-02-05T10:31:57Zcom_10324_1159com_10324_931com_10324_894col_10324_1310

Granja del Río, Alejandra Alducin, Maite Juaristi, J. Iñaki López Santodomingo, María José Alonso Martín, Julio Alfonso 2023-12-30T18:56:33Z 2023-12-30T18:56:33Z 2021 Applied Surface Science, September 2021, vol. 559, p. 149835 0169-4332 https://uvadoc.uva.es/handle/10324/63856 10.1016/j.apsusc.2021.149835 149835 Applied Surface Science 559 Experimental evidence exists for the enhancement of the hydrogen storage capacity of porous carbons when these materials are doped with metal nanoparticles. One of the most studied dopants is palladium. Dissociation of the hydrogen molecules and spillover of the H atoms towards the carbon substrate has been advocated as the reason for the enhancement of the storage capacity. We have investigated this mechanism by performing ab initio density functional molecular dynamics (AIMD) simulations of the deposition of molecular hydrogen on Pd6 clusters anchored on graphene vacancies. The clusters are initially near-saturated with atomic and molecular hydrogen. This condition would facilitate the occurrence of spillover, since our energy calculations based on density functional theory indicate that migration of preadsorbed H atoms towards the graphene substrate becomes exothermic on Pd clusters with high hydrogen coverages. However, AIMD simulations show that the H atoms prefer to intercalate and absorb within the Pd cluster rather than migrate to the carbon substrate. These results reveal that high activation barriers exist preventing the spillover of hydrogen from the anchored Pd clusters to the carbon substrate. eng info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by-nc-nd/4.0/ © 2021 The Author(s). Attribution-NonCommercial-NoDerivatives 4.0 Internacional Absence of spillover of hydrogen adsorbed on small palladium clusters anchored to graphene vacancies info:eu-repo/semantics/article