Green synthesis of ZnO and α-Fe2O3 nanoparticles using Chinese fan palm leaf extract for their biological and photocatalytic activity evaluation

Abstract

This study presents the green synthesis of zinc oxide (ZnO) and hematite (α-Fe₂O₃) nanoparticles (NPs) using Livistona chinensis (Chinese fan palm) leaf extract as a natural reducing and capping agent. The synthesized NPs were characterized by UV-vis spectroscopy, FT-IR, XRD, and FE-SEM to confirm their structural and morphological features. ZnO and α-Fe₂O₃ NPs exhibited UV absorption peaks at 377 nm and 418 nm, respectively. FT-IR analysis showed characteristic Zn–O and Fe–O stretching bands at 513 cm⁻¹ and 574 cm⁻¹. The average crystallite size of ZnO NPs was 25.40 nm, and that of α-Fe₂O₃ NPs was 12.37 nm. FE-SEM images revealed the triangular-shaped morphology of ZnO NPs, whereas α-Fe₂O₃ NPs were spherical. Both NPs demonstrated significant antibacterial activity. ZnO NPs showed inhibition zones of 15 ± 0.20 and 15 ± 0.90 mm against M. luteus and S. abony at 50 μg mL⁻¹, while α-Fe₂O₃ NPs were more effective against B. subtilis, S. aureus, and E. coli at 100 μg mL⁻¹ dose concentration. Antibiofilm activity was also confirmed against B. subtilis, and moderate antioxidant activity viz. 48.63% for ZnO NPs and 36.79% α-Fe₂O₃ NPs was obtained through DPPH assay. ZnO NPs achieved 79% photocatalytic degradation against malachite green (MG) dye in 90 minutes under visible light, compared to 68% by α-Fe₂O₃ NPs. Molecular docking studies revealed favourable interactions with bacterial quorum-sensing proteins; particularly, α-Fe₂O₃ NPs exhibited strong binding affinity with LasI protein (−10.33 kcal mol⁻¹). These results suggest that the synthesized NPs hold promise for medicinal and environmental applications.