A simple one-pot synthesis of single-crystalline magnetite hollow spheres from a single iron precursor

摘要

This paper presents a facile route using a simple solvothermal reaction to synthesize monodisperse and single-crystalline Fe_30_4 hollow spheres. Fe_30_4 hollow spheres with a mean diameter of 200 nm are fabricated using the coordination compound [Fe(urea)_6]C1_3 as the sole iron source, in the absence of any other additives. TEM, SEM and HRTEM results show that single-crystalline Fe_30_4 hollow spheres are composed of well-aligned nanoparticles. The as-prepared hollow spheres have a Brunauer-Emmett-Teller (BET) surface area of about 16.251 m~2 g~(-1) with an average pore size of 3.537 nm. The hollow spheres display obvious ferromagnetism at room temperature with a saturation magnetization of 79.58 emu g~(-1), a remanent magnetization of 19.1 emu g~(-1) and coercivity of 133.5 Oe. The growth mechanism of single-crystalline Fe_30_4 hollow spheres is attributed to the cooperation of oriented aggregation and Ostwald ripening.