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

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. A nanosheet-like 3D free-standing reduced graphene oxide/porous-carbon composite with N- doping defect was prepared via a facile annealing, followed by hydrothermal and freeze-drying process for improving electrochemical hydrogen storage performance of porous carbon materials. [Display omitted] • The rGO/N-doping porous carbon electrode was prepared via an annealing, combined with hydrothermal and freeze-drying. • The as-prepared composites show nanosheet-like 3D structure, the N-doping porous carbon anchored on the surface of rGO. • Effects of different annealing conditions on doping N content and forms were investigated. • Benefit from the synthetic effect of rGO and N-doping defects, rGO-N800 shows an excellent hydrogen storage performance. [ABSTRACT FROM AUTHOR]