TY - JOUR
T1 - Thermodynamic stability of transition metals on the Mg-terminated MgB2 (0001) surface and their effects on hydrogen dissociation and diffusion
AU - Wang, Yongli
AU - Michel, Kyle
AU - Zhang, Yongsheng
AU - Wolverton, C.
N1 - Publisher Copyright:
© 2015 American Physical Society.
PY - 2015/4/27
Y1 - 2015/4/27
N2 - The hydrogenation of MgB2 is a critical step in the reversibility of several well-known hydrogen storage reactions. Of the many processes that must occur during rehydrogenation, at least two of them take place near the surface: the dissociation of H2 molecules and the subsequent diffusion of atomic hydrogen. Using first-principles calculations, we determine the energetic barriers for these processes on the ideal Mg-terminated MgB2 (0001) surface, as well as on surfaces containing transition metal dopants (Sc-Zn, Y-Cd, Pt, and Au). The calculated dissociation barrier for H2 on the clean surface is 0.89 eV, and the surface diffusion barrier is 0.17 eV. However, we find examples of dopants that significantly decrease the activation barrier for the dissociation of H2. Our calculations suggest that Ni, Cu, and Pd are good catalytic candidates for the surface processes involved in MgB2 rehydrogenation.
AB - The hydrogenation of MgB2 is a critical step in the reversibility of several well-known hydrogen storage reactions. Of the many processes that must occur during rehydrogenation, at least two of them take place near the surface: the dissociation of H2 molecules and the subsequent diffusion of atomic hydrogen. Using first-principles calculations, we determine the energetic barriers for these processes on the ideal Mg-terminated MgB2 (0001) surface, as well as on surfaces containing transition metal dopants (Sc-Zn, Y-Cd, Pt, and Au). The calculated dissociation barrier for H2 on the clean surface is 0.89 eV, and the surface diffusion barrier is 0.17 eV. However, we find examples of dopants that significantly decrease the activation barrier for the dissociation of H2. Our calculations suggest that Ni, Cu, and Pd are good catalytic candidates for the surface processes involved in MgB2 rehydrogenation.
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U2 - 10.1103/PhysRevB.91.155431
DO - 10.1103/PhysRevB.91.155431
M3 - Article
AN - SCOPUS:84929094787
SN - 1098-0121
VL - 91
JO - Physical Review B - Condensed Matter and Materials Physics
JF - Physical Review B - Condensed Matter and Materials Physics
IS - 15
M1 - 155431
ER -