Comparative analysis of morphological, structural and thermal properties of phytogenic zinc oxide nanoparticles derived from two leaves extract

Zinc oxide nanoparticles (ZONPs) were fabricated using environment friendly method with aqueous leaf extracts of Ficus virens and Azadirachta indica as bioreductants and stabilizers. UV–visible spectroscopy of the colloidal samples showed prominent absorption peaks at 300 nm and 301 nm for F. virens and A. indica respectively, indicative of nanoscale zinc oxide. X-ray diffraction (XRD) patterns confirmed hexagonal wurtzite with no secondary phases; however, A. indica extract yielded more uniform particles with higher crystallinity. The optimal reaction ratio (1:1) yielded 68.9% for F. virens and 74.1% for A. indica , demonstrating superior reducing efficiency of the latter. Transmission electron microscopy (TEM) revealed A. indica derived ZONPs were uniformly spherical with diameters ranging from 21 to 26 nm, whereas F. virens derived ZONPs were quasi spherical to irregular, ranging from 22 to 54 nm. Dynamic light scattering (DLS) gave hydrodynamic diameter of 65.9 nm for A. indica and 35.18 nm for F. virens , reflecting differences in surface capping. F. virens derived ZONPs have higher colloidal stability due to their higher zeta potential. Fourier-transform infrared (FTIR) spectroscopy identified organic functional groups on the nanoparticle surfaces, confirming capping by phytochemicals from extracts. Brunauer-Emmett-Teller (BET) analysis confirmed mesoporosity, with surface areas of 20.7 m 2 /g for F. virens and 19.6 m 2 /g for A. indica . Thermogravimetric analysis (TGA) revealed higher thermal stability for A. indica derived ZONPs due to lower organic residue. These differences in characteristics are due to different phytochemical compositions of the two leaf extracts, which influence nucleation and growth during the synthesis process.