Efficient hydrogen storage in defective graphene and its mechanical stability: A combined density functional theory and molecular dynamics simulation study

摘要

A combined density functional theory and molecular dynamics approach is employed to study modifications of graphene at atomistic level for better H-2 storage. The study reveals H-2 desorption from hydrogenated defective graphene structure, V-222, to be exothermic. H-2 adsorption and desorption processes are found to be more reversible for V-222 as compared to pristine graphene. Our study shows that V-222 undergoes brittle fracture under tensile loading similar to the case of pristine graphene. The tensile strength of V-222 shows slight reduction with respect to their pristine counterpart, which is attributed to the transition of sp(2) to sp(3)-like hybridization. The study also shows that the V-222 structure is mechanically more stable than the defective graphene structure without chemically adsorbed hydrogen atoms. The current fundamental study, thus, reveals the efficient recovery mechanism of adsorbed hydrogen from V-222 and paves the way for the engineering of structural defects in graphene for H-2 storage. (C) 2020 The Author(s). Published by Elsevier Ltd on behalf of Hydrogen Energy Publications LLC.