Optimum interlayer distance for hydrogen storage in pillared-graphene oxide determined by H2 pressure-dependent electrical conductance

To establish the relation between optimum interlayer distance for hydrogen storage and electrical conductance, we measured the electrical conductance (G) of 3-dimensional graphene oxide (GOA) depending on high H₂ pressure, from vacuum to 20 bar. The GOA was synthesized using diaminoalkanes with two lengths of alkyl chains, and the interlayer distance of GOA was modulated by thermal annealing. A decrease in G was observed as the H₂ pressure increased. The maximum variation in G was observed at 7.0 Å of interlayer distance. When the interlayer distance-dependent H₂ uptake was considered, we confirmed that the maximum variation in G as well as optimum H₂ uptake occurred at the same interlayer distance, 7.0 Å. The variation in G due to H₂ exposure provides understanding about the behavior of hydrogen molecules on these materials and on the modulation of the electronic structure of the materials.