Synthesis and magnetic properties of mesostructured γ-Fe ₂O₃/carbon composites by a co-casting method

A new co-casting method has been developed to synthesize novel mesostructured γ-Fe₂O₃/C composites with γ-Fe₂O₃ nanoparticles embedded in the wall of ordered mesoporous carbon materials. Fe³⁺ ions were captured by the framework of polyfurfuryl alcohol in the channel of mesoporous silica; during the carbonization process, FeCl₃·6H₂O was decomposed and magnetic γ-Fe₂O₃ nanoparticles were formed and confined in the carbon framework. The γ-Fe₂O ₃/C composite materials were characterized using X-ray diffraction (XRD), nitrogen sorption, Mössbauer spectroscopy, X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and energy-dispersive X-ray (EDX) spectroscopy techniques; the magnetization strength was measured on a vibrating-sample magnetometer (VSM). Different amounts of magnetic iron oxides could be introduced into the composites, which led to varied specific saturation magnetizations. Near-zero coercivity and remanance indicate the superparamagnetic behavior of the composites.