Green Synthesis of Fe₃O₄/RGO Nanocomposite with Enhanced Photocatalytic Performance for Cr(VI) Reduction, Phenol Degradation, and Antibacterial Activity

Herein, we report a novel single-step hydrothermal synthesis of a photocatalytically stable and magnetically separable g-Fe 3 O 4 /RGO nanocomposite in the presence of Averrhoa carambola leaf extract as a natural surfactant for multipurpose water purification application. The Averrhoa carambola leaf extract played a major role in the modification of structural, optical, and electronic properties of the Fe 3 O 4 nanoparticle. At room temperature, the g-Fe 3 O 4 /2RGO nanocomposite showed 97% and 76% of Cr(VI) reduction and phenol degradation, respectively. The higher activity of g-Fe 3 O 4 /2RGO was attributed to the in situ loading of RGO, and the synergism developed between RGO and the super magnetic Fe 3 O 4 nanoparticle results in better separation of photoexcited charge carriers (e – /h + ) which was concluded from photoluminescence and photocurrent measurements. Further, the g-Fe 3 O 4 /2RGO nanocomposite showed better antimicrobial activity against three bacterial pathogens such as Staphylococcus aureous (MTCC-737), Bacillus subtilis (MTCC-736), and Escherichia coli (MTCC-443) compared to GO with respect to a standard antibiotic (30 μg).