Controllable magnetic 3D nitrogen-doped graphene gel: Synthesis, characterization, and catalytic performance

Abstract

Magnetic 3D nitrogen doped graphene gels (MNG) were easily obtained via one-pot hydrothermal synthesis process. It was found that N doping process, reduction of graphene oxide and Fe3O4 nanoparticles (NPs) generation in situ proceeded simultaneously, accompanied by the three-dimensional self-assembly. The MNG hybrids were confirmed to be interconnected poriferous frameworks of graphene sheets with uniform dispersion of Fe3O4 NPs embedded or encapsulated in N-doped graphene layers. The catalytic performance of MNG nanocatalysts was evaluated by the reduction of 4-nitrophenol to 4-aminophenol. It was worth noting that the catalytic activity of MNG hybrids was remarkably enhanced by Fe3O4 NPs loading due to the change of N doping mode induced by the in situ synthesis of these magnetic NPs, which did not alter the C/N mass ratio in fact. Meanwhile, the reaction no longer simply followed the pseudo-zero-order kinetics in late stage, this might be attributed to the enhancement of catalytic activity. Furthermore, MNG nanocatalysts were easily recycled by virtue of their superparamagnetism and exhibited excellent stability.