Multifunctional Fe3O4 modified ZnO dual phase nanostructure for photocatalytic, antibacterial and antioxidant activities

Abstract In this study, Fe3O4 (F), ZnO (Z), and Fe3O4/ZnO (FZ) nanomaterials were synthesized using leaf extract as a reducing and stabilizing agent. Characterization was performed using thermogravimetric–differential thermal analysis, Fourier transform infrared, X-ray diffraction, Brunauer–Emmett–Teller, scanning electron microscopy, high-resolution transmission electron microscopy, diffuse reflectance spectroscopy and photoluminescence techniques. The FZ (2 : 1) composite showed the smallest crystallite size (18 nm), modified band gap (2.46 eV) and highest surface area (97 m2 g−1), suggesting strong catalytic and antibacterial potential. The photocatalytic activity of the synthesized materials against methylene orange (MO) was evaluated, achieving maximum efficiency (96%) for FZ (2 : 1) and minimum efficiency (76%) for F nanoparticles. Furthermore, the antibacterial activities of F and FZ (2 : 1) materials against Enterococcus faecalis and Escherichia coli were assessed. At 100 µg mL−1, inhibition zones of 23.00 ± 0.58 mm for E. faecalis and 21.67 ± 0.24 mm for E. coli were obtained with the composite. These values represent improvements of 38 and 44.5%, respectively, compared with Fe3O4 nanoparticles, which exhibited inhibition zones of 16.67 ± 0.49 and 15.00 ± 0.56 mm. Likewise, the antioxidant activities of F and FZ (2 : 1) were evaluated, with maximum inhibition percentages of 66.31 and 89.32, respectively, at 100 µg ml−1. Overall, the results indicate that the FZ (2 : 1) composite exhibits remarkable efficiency among the synthesized materials.