Structural, optical and magnetic properties of chitosan mediated α-Fe2O3 nanoparticles

Abstract

The environmentally-safe, copious, inexpensive, non-toxic and thermally stable α-Fe2O3 (Hematite) nanoparticles attracted more attention in the recent times. In the present work, we have made an attempt to develop α-Fe2O3 nanoparticles using chitosan (a naturally available biodegradable polymer) as a medium and iron nitrate as precursors. The chitosan gel is first prepared and then solubilized under pressure in water using CO2. Herein, we study the effects of the aqueous chitosan medium on the properties of α-Fe2O3 in terms of size, shape, crystallinity, optical, and magnetic properties. The developed nanoparticles have been characterized for their structural, morphological, thermal, magnetic, and optical properties using XRD, Raman Spectroscopy, HR-TEM, Thermogravimetric analysis, Vibrating sample magnetometer, FTIR, and UV–visible spectroscopy techniques. All the studies confirm the formation of hexagonal crystal structure with a space group R -3 c with polygonal shaped nanoparticles with size ranging from 10 to 30 nm. UV–Visible Spectroscopy shows a standard band gap of 3.34 eV, which is surprisingly much higher in comparison to the existing reports. Magnetic properties reveal the presence of antiferromagnetic nature at room temperature coupled with a ferromagnetic/superparamagnetic behavior.