Structural characterization of green synthesized α-Fe₂O₃ nanoparticles using the leaf extract of Spondias dulcis

Microporous α-Fe₂O₃ nanoparticles were synthesized by employing the extract of Spondias dulcis leaves by green-synthesis technique for the first time. The nanoparticles were characterized by many techniques. A continual absorption band without any peak in UV-vis spectrum and a strong signal for iron and oxygen atoms in EDS confirmed the formation of iron-oxide nanoparticles. Rod-like structures with few aggregations due to magnetic interactions were witnessed in FE-SEM image. Specific peaks belonging to α-Fe₂O₃ nanoparticles were observed in XRD spectrum, and they were very pure and crystalline with a mean particle diameter of 11.38 nm. XPS analysis confirmed oxidation state of Fe and O and portrayed the presence of α-Fe₂O₃. A relatively higher surface area (190.84 m²/g) than reported green-synthesized α-Fe₂O₃ nanoparticles has been obtained by BET analysis, and the pores were microscopic (0.465 nm) in nature. Signature bands for Fe-O (1136 cm⁻¹) and organic moieties stretching vibrations were confirmed by FTIR spectrum. The point of zero charge was determined as 7.97 which is concordant with the published value for α-Fe₂O₃. The thermal stability was ascertained by TGA which showed 28% weight loss. The synthesized α-Fe₂O₃ were superparamagnetic with a very high saturation magnetization value of 34.46 emu/g. Besides, a probable mechanism for the synthesis of microporous α-Fe₂O₃ has been proposed. Therefore, the highly pure, crystalline, and microporous α-Fe₂O₃ with high surface area, synthesized by this green synthesis method could play a significant role in various fields.