New branch on old tree: Green-synthesized RGO/Fe3O4 composite as a photo-Fenton catalyst for rapid decomposition of methylene blue

We report herein the facile fabrication of reduced graphene oxide (RGO) loaded with Fe3O4 nanocomposites (consisting of gauze-like RGO nanosheets and Fe3O4 nanoparticles) through a simple, low-cost and environmental-friendly procedure that employs a brown alga (Sargassum thunbergii) as the solely reducing agent. The RGO/Fe3O4 nanocomposites could work as novel catalytic materials with magnetic and photo-Fenton catalytic properties. In the presence of Sargassum thunbergii, the spherical-shaped Fe3O4 nanoparticles with an average diameter of 7 nm have uniformly anchored on the RGO nanosheets. The material has displayed excellent performance in terms of dye degradation (methylene blue, MB), showing a 96% degradation rate of MB after 120 min irradiation under almost neutral pH environment, and room temperature conditions. After the reaction, the RGO/Fe3O4 nanocomposite could be easily separated and recycled due to its excellent ferromagnetism and superior stability. Our study provides a strong validation of RGO/Fe3O4 remarkable capacity toward visible-light-driven degradation of organic contaminates.