Graphene@Metal Sulfide/Oxide Nanocomposites as Novel Photo-Fenton-like Catalysts for 4-Nitrophenol Degradation

Herein, S-doped graphene flakes-based composites with Fe3O4 and/or CuS nanoparticles (NPs) are reported as photo-Fenton catalysts for the 4-nitrophenol (4-NP) degradation. The S-doped graphene flakes (S-GF) were prepared using a thermal treatment approach, and the nanocomposites by the in situ growth of Fe3O4 and/or CuS onto the S-GF scaffold. The characterization methods confirmed the formation of two- and three-components nanocomposites. The Fe3O4 NPs presented a cubic inverse spinel structure and the CuS phases a covellite structure, both with smaller crystallite sizes in the nanocomposites. The new nanocomposites showed higher ability to catalyze the photo-Fenton 4-NP degradation than the individual components. The S-GF@CuS-Fe3O4 nanocomposite exhibited the best catalytic activity: 95.2 % of 4-NP degradation, a kinetic of pseudo-first order (k=0.016 min(-1)), high photo-Fenton catalytic stability and catalyst's composition/structure preservation. The CuS NPs showed an important role in the photo-Fenton-like catalytic activity improvement.