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MM: Fachverband Metall- und Materialphysik
MM 39: Computational Materials Modelling V
MM 39.11: Vortrag
Donnerstag, 17. März 2011, 18:45–19:00, IFW A
Mechanism of Hydrogen Binding to Metal-Doped Carbon Nanostructures — •Mina Yoon1,2 and Matthias Scheffler1 — 1Fritz-Haber-Institut der Max-Planck-Gesellschaft — 2Oak Ridge National Laboratory, USA
Using quntum mechanical first-principles calculations based on numerical atom-centered orbitals as all-electron basis functions we study the mechanism of hydrogen binding to metal-doped nanoscale carbons. These materials have been widely studied as potential building blocks for hydrogen storage. We systematically investigate and compare the performance of different approaches in describing the interaction between hydrogen and metals doped on nanocarbons and the importance of the vibrational contribution in the formation enthalpy. The employed approaches include various DFT xc functionals, a semi-empirical approach, and Møller-Plesset perturbation theory. By comparing the chemical potential with that of free hydrogen gas at a finite temperature (T) and pressure (p), we identify the (T,p) conditions for hydrogen absorption/desorption. The vibrational contribution to the chemical potential of hydrogen is prominent for dihydrogen adsorption to metals, where its significance dramatically changes depending on the binding characteristics. This feature is illustrated by the example of metal-doped fullerenes and graphenes.