Controlled synthesis and growth mechanism of hematite nanorhombohedra, nanorods and nanocubes

Abstract

The selected-control synthesis of uniform α-Fe2O3 nanoparticles with morphologies of rhombohedra, rods, and cubes was successfully achieved in large quantities by the capping agent–cationic surfactant–CTAB-mediated hydrolysis of FeCl3. The nanoparticles were obtained when the concentration of FeCl3 ranged from 0.01 to 0.05 M at 120 °C. The growth mechanisms of α-Fe2O3 nanorhombohedra, nanorods, and nanocubes were analysed in detail, based on the topotactic transformation of the precursor β-FeOOH with different morphologies under the capping agent mediation. The concentration of FeCl3, the reaction temperature, and the concentration of CTAB are all responsible for the final crystalline morphologies of the α-Fe2O3 nanoparticles. This result may facilitate not only the exploration of controlled approaches of preparing α-Fe2O3 nanoparticles for potential technical applications but also a deeper understanding of the fundamental physical and chemical processes of hydrothermal methods. X-ray powder diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), and field-emission scanning electron microscopy (FE-SEM) were used to characterize the products.

Porous Flower-like α-Fe2O3 Nanostructure: A High Performance Anode Material for Lithium-ion Batteries

“…Smaller particle size means shorter path length for diffusion of Li + lithium ion and electronic transport. Recently, the use of nanostructured α-Fe 2 O 3 as an anode material has attracted interest [24], which is largely promoted by the synthesis of diverse α-Fe 2 O 3 nanostructures, including nanoparticles [25], nanocubes [26] nanorods [27], nanotubes [28], and nanoflowers [29] by various routes.…”

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

“…Nanosized hematite has been synthesized in various shapes such as cubes [7][8][9], rods [10], spheres [11,12], pseudocubes [12], platelets [13], ellipsoids [14,15], nanobelts and dendrite micro pines [16,17]. 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].…”

Erratum to: Microstructure and Magnetic Properties of SrFe12O19 Nano-sized Powders Prepared by Sol-Gel Auto-combustion Method with CTAB Surfactant

“…The higher combustion temperature and its higher exothermicity may lead to the formation of more crystallized and aggregated precursors. Also, presence of surfactant in the sol may affect the morphology of the precursors and facilitates the growth of precursors in some preferred directions leading to the formation of platelet-like morphologies, since there are some reports that represent that the presence of CTAB and its concentration in the aqueous wet chemistry methods affect the [25] morphology of the synthesized nanoparticles of different materials (e.g., α-Fe 2 O 3 , Cu 2 O and Au) [27][28][29]. Figure 6 represents the TEM images of the strontium hexaferrite nano-sized powders with and without CTAB Fig.…”