DFT study of hydrogen adsorption on palladium decorated graphene

IGNACIO LÓPEZ CORRAL; ESTEFANÍA GERMÁN; ALFREDO JUAN; MARÍA ALICIA VOLPE; GRACIELA BRIZUELA

JOURNAL OF PHYSICAL CHEMISTRY C

AMER CHEMICAL SOC

Lugar: Washington; Año: 2011 vol. 115 p. 4315 - 4323

1932-7447

The adsorption of several molecular and dissociative dihydrogen systems on a Pd-decorated graphene monolayer was studied using the density-functional theory. Our calculations show that the most favorable graphene-supported coordination structure is similar to the PdH2 complex in vacuum, where the H-H bond is relaxed but not dissociated. We also computed overlap populations corresponding to bonds and atomic orbital interactions in order to study the evolution of the chemical bonding. During the decoration process with Pd, we detected a weakening of C-C bonds close to the adsorption site and the formation of strong C-Pd bonds, coming from interaction between C 2pz and Pd 5s, 5pz, and 4dz2 orbitals. After H2 molecule adsorption, the H-Pd bond is formed by the H 1s orbital overlap with the Pd 5s orbital, but this interaction became stronger during the atomic hydrogen adsorption. The objective of this work is to contribute to the understanding of the hydrogen uptake of Pd-doped graphene surfaces.