Hydrothermal synthesis, characterization and thermal stability studies of α-Fe2O3 hollow microspheres

Abstract

• Hollow α-Fe 2 O 3 microspheres have been synthesized by a facile and cost-effective hydrothermal method. • The shell of the hollow microspheres was porous and composed of aggregated α-Fe 2 O 3 nanoparticles. • The hollow microspheres exhibited a high surface area and pore volume. • Hollow structure was thermally stable to temperature up to 700 °C and no weight loss was observed up to 1000 °C. • This material has potential application in gas sensing, lithium-ion storage and drug delivery systems. A simple, cost-effective hydrothermal technique was used in this study to successfully fabricate hollow α-Fe 2 O 3 microspheres, using only fructose and anhydrous ferric chloride without any organic solvent or additive. The synthesized α-Fe 2 O 3 hollow microspheres were characterized by X-ray diffraction spectroscopy (XRD), field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR). Based on the results, the shell was composed of aggregated α-Fe 2 O 3 nanoparticles, while the fructose-derived carbon core was decomposed during calcination, leaving a hollow interior. XRD analysis confirmed the presence of the α-phase and the absence of γ-phase Fe 2 O 3. A mean diameter of 595 nm was estimated for the microspheres by the Gaussian fit of the histogram constructed from the diameters measured over the SEM images. EDX spectrum of the sample showed signals attributed to Fe and O, and a homogenous distribution of these elements was confirmed by elemental mapping studies. ATR-FTIR analysis confirmed the bending and stretching vibration modes of the Fe-O bond. TGA-DTA data depicted that thermal stability of α-Fe 2 O 3 hollow microsphere was achieved at 480 °C and no weight loss was observed up to 1000 °C. High-temperature calcination results showed that the material can maintain its hollow morphology up to 700 °C. This material has potential applications in drug delivery, gas sensing, and lithium storage.