Tight-binding study of hydrogen adsorption on palladium decorated graphene and carbon nanotubes

IGNACIO LOPEZ CORRAL; ESTEFANIA GERMÁN; MARÍA A. VOLPE; GRACIELA BRIZUELA; ALFREDO JUAN

INTERNATIONAL JOURNAL OF HYDROGEN ENERGY

PERGAMON-ELSEVIER SCIENCE LTD

Año: 2010 vol. 35 p. 2377 - 2384

0360-3199

In this work we report a theoretical study on the atomic and molecular hydrogen  a theoretical study on the atomic and molecular hydrogen adsorption onto Pd-decorated graphene monolayer and carbon nanotubes by a semiempirical tight-binding method. We first investigated the preferential adsorption geometry, considering different adsorption sites on the carbon surface, and then studied the evolution of the chemical bonding by evaluation of the overlap population (OP) and crystal orbital overlap population (COOP). Our results show that strong C–Pd and H–Pd bonds are formed during atomic hydrogen adsorption, with an important role in the bonding of C 2pz adsorption onto Pd-decorated graphene monolayer and carbon nanotubes by a semiempirical tight-binding method. We first investigated the preferential adsorption geometry, considering different adsorption sites on the carbon surface, and then studied the evolution of the chemical bonding by evaluation of the overlap population (OP) and crystal orbital overlap population (COOP). Our results show that strong C–Pd and H–Pd bonds are formed during atomic hydrogen adsorption, with an important role in the bonding of C 2pz adsorption onto Pd-decorated graphene monolayer and carbon nanotubes by a semiempirical tight-binding method. We first investigated the preferential adsorption geometry, considering different adsorption sites on the carbon surface, and then studied the evolution of the chemical bonding by evaluation of the overlap population (OP) and crystal orbital overlap population (COOP). Our results show that strong C–Pd and H–Pd bonds are formed during atomic hydrogen adsorption, with an important role in the bonding of C 2pz adsorption onto Pd-decorated graphene monolayer and carbon nanotubes by a semiempirical tight-binding method. We first investigated the preferential adsorption geometry, considering different adsorption sites on the carbon surface, and then studied the evolution of the chemical bonding by evaluation of the overlap population (OP) and crystal orbital overlap population (COOP). Our results show that strong C–Pd and H–Pd bonds are formed during atomic hydrogen adsorption, with an important role in the bonding of C 2pz and Pd 5s, 5pz and 4dz 2 orbitals. The hydrogen storage mechanism in Pd-doped carbonbased materials seems to involve the dissociation of H2 molecule on the decoration points and the bonding between resultant atomic hydrogen and the carbon surface. and the bonding between resultant atomic hydrogen and the carbon surface. and the bonding between resultant atomic hydrogen and the carbon surface. materials seems to involve the dissociation of H2 molecule on the decoration points and the bonding between resultant atomic hydrogen and the carbon surface. and the bonding between resultant atomic hydrogen and the carbon surface. and the bonding between resultant atomic hydrogen and the carbon surface. materials seems to involve the dissociation of H2 molecule on the decoration points and the bonding between resultant atomic hydrogen and the carbon surface. and the bonding between resultant atomic hydrogen and the carbon surface. and the bonding between resultant atomic hydrogen and the carbon surface. 2 orbitals. The hydrogen storage mechanism in Pd-doped carbonbased materials seems to involve the dissociation of H2 molecule on the decoration points and the bonding between resultant atomic hydrogen and the carbon surface. and the bonding between resultant atomic hydrogen and the carbon surface. and the bonding between resultant atomic hydrogen and the carbon surface. materials seems to involve the dissociation of H2 molecule on the decoration points and the bonding between resultant atomic hydrogen and the carbon surface. and the bonding between resultant atomic hydrogen and the carbon surface. and the bonding between resultant atomic hydrogen and the carbon surface. materials seems to involve the dissociation of H2 molecule on the decoration points and the bonding between resultant atomic hydrogen and the carbon surface. and the bonding between resultant atomic hydrogen and the carbon surface. and the bonding between resultant atomic hydrogen and the carbon surface. 2 orbitals. The hydrogen storage mechanism in Pd-doped carbonbased materials seems to involve the dissociation of H2 molecule on the decoration points and the bonding between resultant atomic hydrogen and the carbon surface. and the bonding between resultant atomic hydrogen and the carbon surface. and the bonding between resultant atomic hydrogen and the carbon surface. materials seems to involve the dissociation of H2 molecule on the decoration points and the bonding between resultant atomic hydrogen and the carbon surface. and the bonding between resultant atomic hydrogen and the carbon surface. and the bonding between resultant atomic hydrogen and the carbon surface. materials seems to involve the dissociation of H2 molecule on the decoration points and the bonding between resultant atomic hydrogen and the carbon surface. and the bonding between resultant atomic hydrogen and the carbon surface. and the bonding between resultant atomic hydrogen and the carbon surface. z and 4dz 2 orbitals. The hydrogen storage mechanism in Pd-doped carbonbased materials seems to involve the dissociation of H2 molecule on the decoration points and the bonding between resultant atomic hydrogen and the carbon surface. and the bonding between resultant atomic hydrogen and the carbon surface. and the bonding between resultant atomic hydrogen and the carbon surface. materials seems to involve the dissociation of H2 molecule on the decoration points and the bonding between resultant atomic hydrogen and the carbon surface. and the bonding between resultant atomic hydrogen and the carbon surface. and the bonding between resultant atomic hydrogen and the carbon surface. materials seems to involve the dissociation of H2 molecule on the decoration points and the bonding between resultant atomic hydrogen and the carbon surface. and the bonding between resultant atomic hydrogen and the carbon surface. and the bonding between resultant atomic hydrogen and the carbon surface. orbitals. The hydrogen storage mechanism in Pd-doped carbonbased materials seems to involve the dissociation of H2 molecule on the decoration points and the bonding between resultant atomic hydrogen and the carbon surface. and the bonding between resultant atomic hydrogen and the carbon surface. and the bonding between resultant atomic hydrogen and the carbon surface. 2 molecule on the decoration points and the bonding between resultant atomic hydrogen and the carbon surface.