INQUISUR   21779
INSTITUTO DE QUIMICA DEL SUR
Unidad Ejecutora - UE
artículos
Título:
Hydrogen adsorption on palladium dimer decorated graphene: a bonding study
Autor/es:
IGNACIO LÓPEZ CORRAL; ESTEFANÍA GERMÁN; ALFREDO JUAN; MARÍA ALICIA VOLPE; GRACIELA BRIZUELA
Revista:
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
Editorial:
PERGAMON-ELSEVIER SCIENCE LTD
Referencias:
Lugar: Ámsterdam; Año: 2012 vol. 37 p. 6653 - 6665
ISSN:
0360-3199
Resumen:
We report a density-functional theory study of dihydrogen adsorption on a graphene sheet functionalized with palladium dimers considering different adsorption sites on the carbon surface and both molecular and dissociative Pd2H2 coordination structures. Our results show that a (PdH)2 ring without an H-H bond and not dissociative Pd2(H2) complexes are stable adsorbed systems with more elongated Pd-Pd and Pd-H bonds compared to the unsupported configurations caused by C-Pd interactions. In contrast, individual Pd atoms supported on graphene react with H2 to form only a Pd(H2) complex with a relaxed but not dissociated H-H bond. We also performed the Mulliken analysis to study the bonding mechanism during the adsorption process. In most cases, we found donor-acceptor C-Pd and Pd-H interactions in which C 2p, Pd 5s, and H 1s orbitals played an important role. We also found that the adsorption of a second Pd atom close to a PdH2 system destabilizes the H-H bond. In this work we contribute to shed more light on the relation between Pd clustering and the possibility of hydrogen storage in graphene-based materials.