Fig. 3: X-ray diffractometer pattern of Iron oxide nanoparticle

In the following, we focus mainly on recent development and various strategies in the preparation, structure and magnetic properties of various surface functionalized strategies of magnetic iron oxide NPs and their corresponding applications, as well as the research advances on functionalizations of magnetic iron oxide NPs worldwide. Further the problems and major challenges still should be solved are pointed out, and the directions in these researches are also discussed.

Progress in electrochemical synthesis of magnetic iron ..

Sonochemical Synthesis of Highly Luminescent Zinc Oxide Nanoparticles Doped ..

sol–gel synthesis of nearly monodispersed iron ..

The room temperature Mössbauer spectrum () of Sono-STFO40 consists in the superposition of two components: a prevailing central quadrupole doublet (continuous line in blue) assigned [] to Sr(Ti0.6Fe0.4)O2.845 and a complex magnetic hyperfine component associated with five iron sites (12k, 4f1, 4f2, 2a and 2b) in the SrFe12O19 structure [] (continuous color sextet lines). The continuous lines in represent the computer fit of the experimental points in the hypothesis of Lorentzian line shape. This result is in good agreement with the XRD data.

reported the sonochemical synthesis of iron nitride ..

Iron oxide NPs with controlled size and shape are technologically important due to strong correlation between these parameters and magnetic properties. The microemulsion and thermal decomposition methods usually lead to complicated process or require relatively high temperatures. As an alternative, hydrothermal synthesis includes various wet-chemical technologies of crystallizing substance in a sealed container from the high temperature aqueous solution (generally in the range from 130 to 250 °C) at high vapor pressure (generally in the range from 0.3 to 4 MPa). This technique has also been used to grow dislocation-free single crystal particles, and grains formed in this process could have a better crystallinity than those from other processes, so hydrothermal synthesis is prone to obtain the highly crystalline iron oxide NPs.

Saravanan M, Prakash NK, Arasu M, Vijayakumar B, Vincent S. Enhanced antibacterial activity of iron oxide magnetic nanoparticles
Wu W, He Q, Jiang C. Magnetic iron oxide nanoparticles: Synthesis and surface functionalization strategies. Nanoscale Res Lett 2008;3:397-415.

Synthesis, characterization, applications, and challenges of iron ..

Therefore, how to improve the stability and availability of functionalized iron oxide NPs in extreme environmental conditions, how to develop an efficient and orderly magnetic micro- or nano-assembly structures, and how to realize large-scale or industrial synthesis, these problems are urgent to be solved for obtaining a ideal functionalized iron oxide materials.

Sonochemical synthesis of amorphous iron

Sonochemical synthesis of iron colloids.

In recent years, considerable efforts have been devoted to the design and controlled fabrication of nanostructured materials displaying specific functional properties. Organic compounds coated on iron oxide NPs offer a high potential application in several areas. The structure of organic compounds functionalized magnetic iron oxide NPs consists of two major parts: preserved the magnetic property of magnetic iron oxides and preserved the other properties of organic molecules. Generally, if iron oxides were always assumed as the core, its structure can roughly be divided into three types: core-shell, matrix, and shella-core-shellb. As plotted in Fig. , coating an ensemble of iron oxide NPs by organic material yields core-shell nanostructure. In these structures, the cores may be any kind of iron oxide particles, such as magnetite or maghemite. Likewise, the shells may consist of any sort of materials including organic ones. Matrix structure includes two typical structures: mosaic and shell-core. Comparatively speaking, the shell-core structure consists of an organic compound NPs core and iron oxide particle shells. Iron oxide NPs may connect with the organic core by the interaction of chemical bonds. The mosaic structure comprising the shell layer was made of organic molecules coated to a lot of uniformly iron oxide magnetic NPs. Among the different matrixes that can be used to embed the NPs, polymers are of particular interest because of their wide range of properties. Furthermore, a shell layer made of organic molecules coated to a shell-core structurally functionalized iron oxide NPs that will form the shella-core-shellbstructure, which occurs in many current reports and generally obtained bylayer-by-layertechnology. The shellamay be the polymer or biomolecules, likewise, the shellbcan be the same or different functional materials. Moreover, multi-component conducting organic material systems with iron oxide NPs can be tailored to obtain desired mechanical properties besides novel electrical, magnetic, and optical properties.

Insights into the sonochemical synthesis and properties of salt-free intrinsic plutonium colloids

controlled synthesis of monodisperse magnetic Iron oxide ..

With controlled structure and interface interactions, nanocomposites can exhibit novel physical and chemical properties that will be essential for future technological applications. As illustrated in Fig. , if iron oxides were always assumed as the core, the structure of inorganic compound functionalized iron oxide NPs can roughly be divided into five types: core-shell, mosaic, shell-core, shell-core-shell, and dumbbell. Many studies have shown that in the presence of core-shell structure composite NPs, such as Fe3O4@Au NPs, its two-layer structure include magnetite core and gold shell in the outer layer. Generally, superparamagnetic colloid particles offer some attractive possibilities in bioseparation or biodetection, they should be made at dimensions they are comparable to those of a virus (20–500 nm), a protein (5–50 nm), or a DNA (10–100 nm). Nevertheless, the reactivity of iron oxide NPs has been shown to greatly increase as their dimensions are reduced, and particles with relatively small sizes may undergo rapid biodegradation when they are directly exposed to biological environments. Therefore, matrix-dispersed iron oxide NPs can be prepared in a variety of different states and greatly increase the size of naked iron oxide NPs, the three representative states have been shown in Fig. . The mosaic structure are commonly produced in the hollow silica spheres with iron oxide NPs, and the shell-core structure can be formed by individual iron oxides which are connected their inner layer. Additionally, shella-core-shellbtype composite NPs can be obtained bylayer-by-layertechnology and also can be overcome the above limitations. The shellamay be the metal NPs, polymer, and quantum dots, likewise, the shellbcan be the same or different functional materials. This type of composite NPs is expected to greatly expand the application scope of iron oxide NPs. Dumbbell structure is commonly formed through epitaxial growth of iron oxide (or inorganic compound NPs) on the inorganic compound seeds (or ion oxide NPs), and finally obtained the bifunctional composite NPs.