Porous Fluorine-Doped γ-Fe₂O₃ Hollow Spheres: Synthesis, Growth Mechanism, and Their Application in Photocatalysis

Abstract

Porous fluorine-doped maghemite(γ-Fe2O3) hollow spheres have been prepared by facile route based on solvothermal reaction and sequential calcinations. The composition and morphology of the as-prepared samples were characterized by various techniques. The SEM and TEM results showed that the as-synthesized products exhibited a spherical morphology with porous hollow structures. Ultraviolet-visible (UV-vis) diffuse reflectance spectra display that the optical performance of γ-Fe2O3 products are related to their structure and the fluorine concentrations. The porous hollow structured fluorine-doped γ-Fe2O3 spheres exhibit ferromagnetic properties with relatively high saturation magnetization at room temperature. According to the experimental results, a formation mechanism of the fluorine-doped γ-Fe2O3 hollow spheres has been presented. Under UV light irradiation, the photocatalytic degradation activities of the as-synthesized fluorine-doped γ-Fe2O3 samples for RhB dye were 2-5 times higher than that of the undoped sample. The prepared fluorine-doped γ-Fe2O3 hollow spheres will also aroused great interest for their application in catalysis, separation technology, sensors, nanotechnology, and biomedical fields.

Morphological Effect in Photocatalytic Degradation of Direct Blue over Mesoporous TiO2 catalysts

“…The TiO 2 with daisy‐like and spherical structure yield the lower band gap energy. In previous report by Zhu et al., the band gap energies of semiconductor nano‐materials were much depended on their structures. TiO 2 particles with nanoburrs or lateral organization were inclined to produce lower band gap energy …”

“…Compared to TiO 2 ‐SL, the other three TiO 2 exhibits a much stronger adsorption in the UV‐visible range of 200–800 nm. Calculation using Kubelka–Munk method based on the diffuse reflectance spectra could obtain the relative band gap of TiO 2 synthesized . As shown in Figure b, the band gap energy Eg can be calculated by the Tauc plots (αhν) 2 and hν relationship .…”

Crystal Structure‐ and Morphology‐Driven Electrochemistry of Iron Oxide Nanoparticles in Hydrogen Peroxide Detection

“…Their physicochemical properties can be driven by particle size distribution and morphology of the as‐prepared materials. So far, it has been reported that among electric properties, it is also possible to change magnetic properties, photocatalytic activity, and features for targeted drug delivery application easily by the shape of nanoparticles. The type of morphology is related to the surface area; intrinsic morphology can considerably increase the accessible surface, thus offering a large capacity for loading various compounds and ions (e.g., in lithium‐ion batteries) …”

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