Biosynthesis of hematite phase α-Fe2O3 nanoparticles using an aqueous extract of Rosmarinus officinalis leaves

Abstract

Biosynthesized hematite phase α-Fe2O3 nanoparticles (NPs) have been successfully demonstrated via an entirely green process mediated aqueous extract of Rosmarinus officinalis (rosemary) leaves acting as both stabilizing and capping agents. The synthesis was free of solvents and surfactants to adhere to green chemistry principles and the impartation of environmental benignity. To achieve the goal of this study, the main physical properties of the biosynthesized α-Fe2O3 NPs were carried-out using complementary techniques namely, field emission scanning electron microscopy (FESEM) which revealed the self-assembled, highly agglomerated NPs, and the average size was found to peak at 6.531 ± 0.148 nm while X-ray diffraction (XRD) exhibited several Bragg diffraction peaks in line with the rhombohedral structure and the crystallinity nature of α-Fe2O3 NPs with an average size within the range of 7.412–10.742 nm in agreement with the FESEM results. The energy-dispersive X-ray spectroscopy (EDS) elucidated the presence of Fe and O in addition to contaminating elements from the natural extract while attenuated total reflectance-Fourier transform infrared (ATR-FTIR) depicted Fe-O chemical bonds. Besides, the photoluminescence (PL) emission spectrum indicated the existence of surface defects and oxygen vacancies.