Hydrogen absorption in bulk BC3: a first-principles study.
We have performed first-principles calculations for H absorption, H2 dissociation, and H diffusion in bulk BC3, a graphitelike layered structure. We show that in bulk BC3, H2 can dissociatively (and exothermically) absorb at low coverages. Several low-energy pathways have been computed for the dissociation process. The dissociation barriers are on the order of 0.2 eV or less. This presents a striking contrast to the situation in pure graphite and also on monolayer BC3(0001), where H2 dissociative absorption is considerably more difficult. Hydrogen absorption at high coverages has also been investigated; we find that the absorption enthalpy becomes moderately more exothermic at higher coverages. The calculated range of H binding energies is close to the desired value for reversible hydrogen storage.
Zhang
Changjun
C
Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom.
Alavi
Ali
A