One-Pot Reaction and Subsequent Annealing to Synthesis Hollow Spherical Magnetite and Maghemite Nanocages

Abstract

Water-soluble hollow spherical magnetite (Fe3O4) nanocages (ca.100 nm) with high saturation magnetization are prepared in a one-pot reaction by sol-gel method and subsequent annealing to synthesise the maghemite (γ-Fe2O3) nanocages with similar nanostructures. The nanocages have been investigated by powder X-ray diffraction (XRD), transmission electron microscope (TEM), high-resolution transmission electron microscope (HRTEM), and superconducting quantum interference device (SQUID). The results indicated that glutamic acid played an important role in the formation of the cage-like nanostructures.

Electrodeposition of micro-nano size Fe3O4 crystals anchored on flexible buckypaper

“…In addition, Fe 3 O 4 also has desirable catalytic properties that can be used as electro-catalyst for oxygen reduction [4,5]. However, it has been proven to be challenging to produce stable Fe 3 O 4 nanoparticles with accurate control over size, and geometry [6]. The Fe 3 O 4 crystals tend to agglomerate into large clusters due to their high surface energy and spontaneous magnetization, which results in a loss of dispersity and effective surface area and therefore diminished catalytic activity [7].…”

Highly crystalline superparamagnetic iron oxide nanoparticles (SPION) in a silica matrix

“…Complex magnetic properties of nanosized iron oxides have been widely discussed and a wide range of magnetic properties has been obtained [1,[56][57][58][59][60][61][62]. Dutta et al reported nearly defect-free maghemite nanocrystals of a size of about 7 nm, high saturation magnetization M S = 80 emu/g close to bulk value, whereas at the same time, very low coercivity H C = 20 Oe was obtained [63].…”

Novel doping for synthesis monodispersed TiO2 grains filled into spindle-like hematite bi-component nanoparticles by ion implantation

“…In the insert of Figure 6(a), the photographs demonstrate that the as-obtained samples can be magnetic separated by an external magnetic field. 26 This figure also illustrates the facile, fast separation process of the bi-component NPs during the experiments. The magnetization curves were measured as a function of temperature with different applied fields between 10 and 300 K using field-cooling (FC) and zero-field-cooling (ZFC) procedures.…”