INVESTIGADORES
RAMOS Susana Beatriz
congresos y reuniones científicas
Título:
Atomistic Modeling of H absorption in Pd nanoparticles
Autor/es:
E. CRESPO; M. RUDA; S. RAMOS DE DEBIAGGI
Lugar:
Buenos Aires
Reunión:
Congreso; 15th. Internacional Symposium on Metastable, Amorphous and Nanostructured Materials; 2008
Resumen:
Understanding the process
of absorption and desorption of H in metals is important in the design
of new materials apt for safe H storage. In the case of Palladium, a very
strong H absorber, this property has also been used for other important applications such as catalysts for a number
of industrial reactions.
In this work we analyze the effect
of the size of nano-particles on the properties of absorption of H in
Palladium. Because of the higher proportion of surface atoms in nanoparticles
compared with the bulk, the pressure-composition (P-C) isotherms of the nanoparticles are modified with respect to
the corresponding bulk ones. We made atomistic simulations of Pd nanoparticles
with H in at different concentrations. We performed Monte Carlo simulations in
the TPmN ensamble to calculate the P-C
isotherms. We used potentials of the Embedded Atom (EAM) type to
describe the Pd-H interaction. We considered the potentials recently developed
Pd-H EAM potentials which describe, in a satisfactory way, the Pd-H interaction
up to higher H concentrations than other potentials available in the
literature.
Previous simulations results show
that H is absorbed primarily in the surface before diffusing into the inside of
small Pd clusters. In this work we show the predictions of Zhou?s potentials
regarding the evolution of the equilibrium microstructure of Pd nanoparticles
as a function of their size and H concentration.