Role of catalysts in dehydrogenation of MgH2 nanoclusters.
A fundamental understanding of the role of catalysts in dehydrogenation of MgH(2) nanoclusters is provided by carrying out first-principles calculations based on density functional theory. It is shown that the transition metal atoms Ti, V, Fe, and Ni not only lower desorption energies significantly but also continue to attract at least four hydrogen atoms even when the total hydrogen content of the cluster decreases. In particular, Fe is found to migrate from the surface sites to the interior sites during the dehydrogenation process, releasing more hydrogen as it diffuses. This diffusion mechanism may account for the fact that a small amount of catalysts is sufficient to improve the kinetics of MgH(2), which is essential for the use of this material for hydrogen storage in fuel-cell applications.
Larsson
Peter
P
Condensed Matter Theory Group, Physics Department, Uppsala University, Box 530, S-751 20 Uppsala, Sweden.
Araújo
C Moysés
CM
Larsson
J Andreas
JA
Jena
Puru
P
Ahuja
Rajeev
R