GREEN SYNTHESIS OF ZINC OXIDE NANOPARTICLES USING PHYLLANTHUS RETICULATUS POIR. LEAF EXTRACT: STRUCTURAL, OPTICAL, MORPHOLOGICAL, AND ELEMENTAL CHARACTERISATION

Abstract

Plant-mediated routes to zinc oxide (ZnO) nanoparticles (NPs) are attractive because they avoid toxic reagents, but many reports support their structural and compositional claims only qualitatively. Here, ZnO NPs were prepared by alkaline precipitation of zinc acetate in the presence of an aqueous leaf extract of Phyllanthus reticulatus Poir., followed by washing, drying at 80 °C, and calcination, and were characterised by UV–Visible spectroscopy, FTIR, XRD, SEM–EDX, and TEM with SAED. XRD confirmed hexagonal wurtzite ZnO (JCPDS 36-1451) with refined lattice parameters a = 3.257 Å and c = 5.220 Å, no distinct reflections from secondary crystalline phases, and a mean Scherrer crystallite size of 10 ± 2 nm. The UV–Vis spectrum showed a band-edge shoulder at about 340–400 nm and a Tauc direct optical band gap of ≈3.18 eV. FTIR showed a strong Zn–O band at 565 cm−1, along with O–H, H–O–H, and C–O bands from surface hydroxyl groups, adsorbed water, and residual organic matter. SEM showed sub-micrometre agglomerates of rounded grains, whereas TEM showed quasi spherical primary particles of 15.3 ± 6.2 nm (n = 7) with resolved lattice fringes. SEM–EDX detected Zn and O with Zn:O atomic ratios of 0.46 and 0.41, i.e., oxygen-rich relative to stoichiometric ZnO, consistent with surface hydroxyl, adsorbed water, and organic residues. Because zinc was precipitated with NaOH, the extract is best viewed as a complexing, capping, and stabilising medium rather than a reducing agent. The results provide baseline structural data for P. reticulatus-derived ZnO and identify the additional measurements needed before application studies.