One-pot green synthesis of reduced graphene oxide (RGO)/Fe₃O₄ nanocomposites and its catalytic activity toward methylene blue dye degradation

The reduced graphene oxide (RGO)/Fe₃O₄ nanocomposites were synthesized through a facile one-pot green synthesis by using solanum trilobatum extract as a reducing agent. Spherical shaped Fe₃O₄ nanoparticles with the diameter of 18 nm were uniformly anchored over the RGO matrix and the existence of fcc structured Fe₃O₄ nanoparticles over the RGO matrix was ensured from X-ray diffraction patterns. The amide functional groups exist in the solanum trilobatum extract is directly responsible for the reduction of Fe³⁺ ions and GO. The thermal stability of GO was increased by the removal of hydrophilic functional groups via solanum trilobatum extract and was further promoted by the ceramic Fe₃O₄ nanoparticles. The I_D/I_G ratio of RGO/Fe₃O₄ was increased over GO, indicating the extended number of structural defects and disorders in the RGO/Fe₃O₄ composite. The catalytic efficiency of prepared nanostructures toward methylene blue (MB) dye degradation mediated through the electron transfer process of BH4⁻ ions was studied in detail. The π–π stacking, hydrogen bonding and electrostatic interaction exerted between the RGO/Fe₃O₄ composite and methylene blue, increased the adsorption efficiency of dye molecules and the large surface area and extended number of active sites completely degraded the MB dye within 12 min.