Preparation and magnetic properties of spindle porous iron nanoparticles

Spindle porous iron nanoparticles were firstly synthesized by reducing the pre-synthesized hematite (α-Fe2O3) spindle particles with hydrogen gas. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), nitrogen adsorption/desorption isotherms and vibrating sample magnetometry (VSM). A lattice shrinkage mechanism was employed to explain the formation process of the porous structure, and the adsorbed phosphate was proposed as a protective shell in the reduction process. N2 adsorption/desorption result showed a Brunauer–Emmett–Teller (BET) surface area of 29.7 m2/g and a continuous pore size distribution from 2 nm to 100 nm. The magnetic hysteresis loop of the synthesized iron particles showed a saturation magnetization of 84.65 emu/g and a coercivity of 442.36 Oe at room temperature.