Observation of giant 3D graphenic vesicles encapsulating hydrogen

Abstract

Graphene is one of the few materials that is impermeable to hydrogen. Computational studies suggest that giant fullerenes such as C₇₂₀ may be candidates for practical hydrogen storage. The current state-of-the-art in hydrogen confinement by aromatic carbon structures are C₇₀ fullerenes which confine up to 2 molecules of H₂. No experimental demonstration of the encapsulation of bulk H₂ in 3D grahphenes has prevously been reported. Here we describe meso-scale, graphenic vesicles with diameters up to 90 nm, more than 110 times larger than C₇₀ and 35 times larger than C₇₂₀. Electron energy-loss spectrum imaging and core-loss spectroscopy indicate that vesicles may contain H₂ gas. ²H nuclear magnetic resonance studies confirm that these vesicles contain encapsulated H₂/D₂. The encapsulation has been found to persist for over 5 years at room temperature and ambient pressure, demonstrating the high stability and impermeability of the vesicle shells. The synthesis of these novel meso-graphenic structures and the demonstration of long-term, multi-year hydrogen encapsulation may open the door to 3D meso-graphenic materials as a new approach for practical hydrogen storage.