Shape Control of Monodisperse Hematite Particles by Organic Additives in the Gel–Sol System

A closer look at the synthesis and formation mechanism of hematite nanocubes

“…The final hematite particle size and shape can be tuned by adjusting synthesis parameters such as the concentration of the reactants [7], duration of the reaction [18], ionic strength [19,20], reaction temperature, surfactants [10], presence of hematite seed [21] and pH of the solution [19]. The addition of organic additives to aqueous reaction mixtures was shown to have an appreciable effect on the geometry of hematite particles [22]. Changing the ratio of solvent mixtures strongly influences the final shape, yielding spindle, rhombohedral, or cubical geometries particularly in the case of ethylene diamine/ethanol mixtures [9].…”

Eu-doped α-Fe2O3 nanoparticles with modified magnetic properties

“…As to morphology, different habits may be assumed (hexagonal plate, rhombohedra, spindle, rod, ellipsoid, cube, disc, sphere, star, bipyramid, wire, hollow sphere) [7], as morphology depends, inter alia, on the presence in the synthesis medium of surfactants [10] and [11], cations [3], [12], [13], [14] and [15] and, especially, anions [16], [17], [18] and [19], which all may cause an anisotropic growth by driving it along certain crystallographic directions. For instance, chloride ions (Cl−) restrain the growth in the direction normal to the {0 1 2} faces, so yielding micro particles with a pseudo-cubic shape [18].…”

Formation of Monodispersed Nano‐ and Micro‐Particles Controlled in Size, Shape, and Internal Structure

“…Such a porous internal structure is also observed with ellipsoidal hematite prepared in the presence of organic compounds such as hydroquinone, EDTA, NTA, etc. [32]. The organic adsorptives were also found to be mostly incorporated into the interiors of the particles.…”