Document Type : Research Article
Iran University of Science and Technology
In this study, a high-surface-area and high-porosity nanostructured iron (III) oxide was produced using a supercritical carbon dioxide (CO2) dryer. Iron (III) oxide was synthesized using the sol-gel method. The resulting gels were dried at two different conditions, i.e., ambient drying at 80 oC and supercritical CO2 drying. The produced iron oxide xerogel and aerogel were then calcined at 350 oC for 4 hours. Structural and chemical properties of iron (III) oxide nanostructures were investigated using X-ray diffraction (XRD), N2 adsorption-desorption (BET), and field emission scanning electron microscopy (FE-SEM) analyzes. The results showed that iron (III) oxide aerogel consisted of spherical nanoparticles. The X-ray diffraction pattern demonstrated that the aerogel had a crystalline phase of pure hematite (α-Fe2O3). In addition, the produced aerogel had a specific surface area of 140 m2/g, pore volume of 0.32 cm3/g, and average pore diameter of 8.9 nm. The produced xerogel possessed a specific surface area of 65 m2/g, pore volume of 0.18 cm3/g, and an average pore diameter of 10.8 nm. Therefore, the results confirmed that drying of iron oxide nanostructures using the home-made supercritical dryer lead to better preservation of the porous structure.