A simple way to prepare reduced graphene oxide nanosheets/Fe₂O₃-Pd/N-doped carbon nanosheets and their application in catalysis

The catalysts with Pd and γ-Fe₂O₃ nanoparticles embedded between reduced graphene oxide nanosheets (rGS) and N-doped carbon nanosheets (NCS) were prepared through a two-step method. Firstly, graphene oxide nanosheets (GS)/prussian blue (PB)-Pd/polypyrrole (PPy) composites were synthesized by using pyrrole monomer as reductant, K₃Fe(CN)₆ and PdCl₂ as oxidants in the presence of GS via a redox reaction. Subsequently, the as-obtained GS/PB-Pd/PPy composites were calcinated in N₂ atmosphere. During the heat-treatment, carbonization of PPy to NCS, conversion of nonmagnetic PB to magnetic γ-Fe₂O₃ nanoparticles, and reduction of GS to rGS were finished, simultaneously. rGS/Fe₂O₃-Pd/NCS composites exhibited good catalytic activity toward reduction of 4-nitrophenol. The rate constant k and turnover frequency were calculated and compared with recent reports. Owing to γ-Fe₂O₃ nanoparticles, the rGS/Fe₂O₃-Pd/NCS composites could be quickly separated by magnet and reused without obvious decrease in activity.