N doping porous carbon embedded in self-assembled three-dimensional reduced graphene oxide networks for electrochemical hydrogen storage

Abstract

Electrochemical hydrogen storage can realize reversible hydrogen absorption and desorption at room temperature and pressure, which has attracted extensive attention recently. A nanosheet-like reduced graphene oxide (rGO)-porous carbon composite with N-doping defect is prepared via a facile annealing, followed by hydrothermal and freeze-drying process. After N-doping, the porous carbon materials exhibit rich pore structure, and high pyridine nitrogen and pyrrolic nitrogen content. Adding them into the graphene self-assembly process, the aggregation tendency of graphene sheets can be reduced, the composite shows a free-standing 3D porous structure. Benefit from the synthetic effect between the rGO conductive network, the hierarchical porous structure, and the doping of N atoms, the rGO-N800 delivers a high hydrogen storage capacity of 266.3 mAh g−1 at 200 mA g−1 after 100 cycles. Moreover, the reversible capacities of the composite can reach 288.4, and 267.1 mAh g−1 at 1000 mA g−1 and 2000 mA g−1, respectively. The outstanding electrochemical performance of the composite demonstrates a promising direction for design carbon-based hydrogen storage materials.