One-pot preparation of ternary reduced graphene oxide nanosheets/Fe2O3/polypyrrole hydrogels as efficient Fenton catalysts.

Ternary reduced graphene oxide nanosheets (rGSs)/Fe2O3/polypyrrole (PPy) hydrogels with Fe2O3 nanoparticles (NPs) embedded between rGSs and PPy layer were prepared in one-pot. The ternary hydrogels exhibited an interconnected and porous three-dimensional network with co-existence of macropores and mesopores. Fe2O3 NPs uniformly dispersed on rGS surface with the diameter of 8.8nm. Control experiments were carried out to investigate the roles of components in formation of ternary hydrogels. During heterogeneous Fenton degradation of methylene blue (MB) dyes, the ternary hydrogels exhibited much better removal efficiency than the reference samples, not only because rGSs and PPy layer altered the adsorption, dispersity and diameter of Fe2O3 NPs; but also owing to the structural merits of ternary hydrogels. The effects of operating conditions, such as initial MB concentrations, dosages of catalysts and H2O2, were carefully investigated. With the help of Fe2O3 NPs, ternary rGSs/Fe2O3/PPy hydrogels could be easily separated via a magnet. In recycling experiments, they showed superior reusability.