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.