Eco-friendly fabrication of Fe₃O₄/α-MnO₂ nanocomposites using Pentas schimperiana leaf extract for enhanced biomedicinal and environmental applications

In this study, single-phase Fe3O4 (F), α-MnO2 (M), and double-phase Fe3O4/α-MnO2 (FM) materials were synthesized using pentas schimperiana plant extract as a reducing and stabilizing agent. The fabricated materials were analyzed via thermogravimetric analysis–differential thermal analysis (TGA-DTA), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS), high-resolution transmission electron microscopy (HRTEM), diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), and photoluminescence (PL) techniques to study weight loss, functional groups, crystallite size, surface morphology, band gap, oxidation state, and electron–hole separation performance of the materials. XRD patterns confirmed the crystalline structure of the prepared composite. SEM images of the composite exhibited a spherical morphology with an average size of around 17 nm. HRTEM findings indicate the close contact between the M and F samples. The band gap of material F decreased from 2.38 eV to 2.14 eV. The photocatalytic potential of the prepared materials was explored toward methyl orange, achieving maximum degradation efficiencies of 97% for FM, 76% for F, and 73% for M. In addition, the antibacterial potential of F, M, and FM materials against Staphylococcus aureus and Escherichia coli was evaluated. Inhibition zones of 22.33 ± 0.49 mm for S. aureus and 20.67 ± 0.34 mm for E. coli were obtained for FM material. Likewise, the antioxidant performance of F, M, and FM was examined. The highest radical scavenging activity (RSA) values of 66.31 ± 0.47%, 62.41 ± 0.54%, and 81.43 ± 0.51% were observed for F, M, and FM, respectively. Overall, the results of this study signify the noteworthy efficacy of the FM nanomaterial.