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Título
Steric and chemical effects on the hydrogen adsorption and dissociation on free and graphene–supported palladium clusters
Año del Documento
2017
Editorial
Elsevier
Documento Fuente
Computational and Theoretical Chemistry 1107, 23-29 (2017)
Abstract
Palladium doping enhances the hydrogen storage capacity of nanoporous carbons. The purpose of this
work is to asses the effect of the carbonaceous support on the adsorption of hydrogen on Pd clusters.
Hydrogen adsorbs on Pd clusters following two channels: molecular adsorption and dissociative
chemisorption. These two adsorption channels are investigated on free Pd clusters and Pd clusters supported
on pristine and defective (with vacancies) graphene using the Density Functional Formalism. Pd6
is taken as case study. Free Pd6 can adsorb twelve hydrogen molecules in the molecular form, a number
higher than the nine and eight molecules that can be adsorbed on the cluster supported on pristine graphene
and on a graphene vacancy, respectively. However the most stable adsorption channel is, in all
cases, the dissociative chemisorption of hydrogen. As the cluster is being loaded with hydrogen, there
is a competition between the two adsorption channels. Pd6 supported on a graphene vacancy is able to
dissociate three hydrogen molecules, whereas the free cluster can dissociate up to seven molecules. In
both cases, six additional molecules can be adsorbed in the molecular form. The higher saturation limit
obtained for the free clusters is explained in terms of the steric and chemical effects of the supporting
layer. These effects are of primarily importance to asses the role of the Pd dopant on the adsorption
and storage of hydrogen on nanoporous carbons.
Palabras Clave
hydrogen storage
graphene
palladium clusters
Revisión por pares
SI
Patrocinador
This work was supported by MICINN of Spain (Grant MAT2014- 54378-R)
and Junta de Castilla y León (Grant VA050U14).
and Junta de Castilla y León (Grant VA050U14).
Idioma
eng
Derechos
openAccess
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