Abstract
A facile urea-hydrolysis calcination process for the preparation of α-Fe2O3 nanoparticles and α-Fe2O3 nanorods was introduced. The effects of hydrolysis temperature, Fe3+ concentration, and the molar ratio of urea and Fe3+ on nanorod-like precursors and α-Fe2O3 nanomaterials were investigated. The average length and diameter of the nanorod precursors increased with the increasing hydrolysis temperature, Fe3+ concentration, and molar ratio of urea and Fe3+. When the molar ratio of urea and Fe3+ was not less than 5, the α-Fe2O3 nanoparticles were produced. However, when the molar ratio was not greater than 4, the α-Fe2O3 nanorods could be obtained. In addition, the average diameter of the α-Fe2O3 nanoparticles was the largest when the hydrolysis temperature was 85 °C. With the increase in Fe3+ concentration, the average diameter of the α-Fe2O3 nanoparticles was enlarged. The average length and diameter of the α-Fe2O3 nanorods increased with the increase in hydrolysis temperature and Fe3+ concentration. All the results suggested that the rod-like structure of the precursors provided a possibility and the template for the fabrication of α-Fe2O3 nanorods, and the content of Fe3+ in the rod-like precursors played the decisive role in the morphology of the α-Fe2O3 nanomaterials.
Highlights
The phase identification and composition analysis of the α-Fe2O3 nanomaterials were characterized by Rigaku D/max 2500 PC x-ray diffraction (XRD) with Cu–Kα radiation; the morphology was investigated by scanning electron microscopy (SEM)
The XRD patterns of α-Fe2O3 nanoparticles and α-Fe2O3 nanorods calcined at 600 ○C for 4 h from their corresponding precursors are shown in
As shown in Fig. 1(C), there were no characteristic peaks of urea in FTIR of the α-Fe2O3 nanomaterials, so it could be demonstrated that the undecomposed urea was absent in the α-Fe2O3 nanomaterials after calcination
Summary
There are many kinds of iron oxides, for instance, hematite (α-Fe2O3), maghemite (γ-Fe2O3), wustite (FeO), and magnetite (Fe3O4). Among them, hematite is an n-type semiconductor and α-Fe2O3 is often the final form of other iron oxides after thermal transformation. Hematite is very common in the Earth’s crust, and it is the thermodynamically most stable iron oxide. The nanostructured α-Fe2O3 has many excellent properties, such as good stability, environmental friendliness, corrosion resistance, stability under alkaline conditions, and facile preparation. α-Fe2O3 nanomaterials are widely applied in gas sensing materials, lithium ion batteries, photocatalysts, wastewater treatment, electric heating devices, solar cells, and so on, which has attracted many domestic and international researchers’ interest in the preparation of α-Fe2O3 nanomaterials with various shapes and sizes. There are many kinds of iron oxides, for instance, hematite (α-Fe2O3), maghemite (γ-Fe2O3), wustite (FeO), and magnetite (Fe3O4).. Hematite is an n-type semiconductor and α-Fe2O3 is often the final form of other iron oxides after thermal transformation.. Hematite is very common in the Earth’s crust, and it is the thermodynamically most stable iron oxide.. Scitation.org/journal/adv homogeneous and purity products and recyclability of the reaction solution. In this project, we successfully prepared α-Fe2O3 nanoparticles and α-Fe2O3 nanorods via the facile urea-hydrolysis calcination process and the influence rules of the hydrolysis temperature, Fe3+ concentration, and the molar ratio of urea and Fe3+ on nanorod precursors and α-Fe2O3 nanomaterials were investigated. The fabrication mechanisms and the reaction equations of the ureahydrolysis calcination process for α-Fe2O3 nanomaterials were analyzed
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