Visible-Light-Driven Photocatalytic Activity of Magnetic BiOBr/SrFe12O19 Nanosheets

Abstract

Magnetic BiOBr/SrFe12O19 nanosheets were successfully synthesized using the hydrothermal method. The as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), and UV-visible diffused reflectance spectra (UV-DRS), and the magnetic properties were tested using a vibration sample magnetometer (VSM). The as-produced composite with an irregular flaky-shaped aggregate possesses a good anti-demagnetization ability (Hc = 861.04 G) and a high photocatalytic efficiency. Under visible light (λ > 420 nm) and UV light-emitting diode (LED) irradiation, the photodegradation rates of Rhodamine B (RhB) using BiOBr/SrFe12O19 (5 wt %) (BOB/SFO-5) after 30 min of reaction were 97% and 98%, respectively, which were higher than that using BiOBr (87%). The degradation rate of RhB using the recovered BiOBr/5 wt % SrFe12O19 (marked as BOB/SFO-5) was still more than 85% in the fifth cycle, indicating the high stability of the composite catalyst. Meanwhile, after five cycles, the magnetic properties were still as stable as before. The radical-capture experiments proved that superoxide radicals and holes were main active species in the photocatalytic degradation of RhB.

“Quasi-In Situ Synthesis of Oxygen Vacancy-Enriched Strontium Iron Oxide Supported on Boron-Doped Reduced Graphene Oxide to Elevate the Photocatalytic Destruction of Tetracycline”

“…An estimated band gap of the SrFeO 3 @B-rGO composite is calculated to be 1.63 eV, while the band gap of SrFeO 3 @B-rGO is significantly reduced to 1.63 eV. This might be attributed to the synergistic interaction between SrFeO 3 and SrFeO 3 @B-rGO (Figure b). , …”

Application of Spinel and Hexagonal Ferrites in Heterogeneous Photocatalysis

“…Another visible-light active structure was proposed by Xie et al, who prepared a SrFe 12 O 19 /BiOBr 2D-2D nanocomposite for the degradation of Rhodamine B (λ > 420 nm) [131]. An increase in the activity of BiOBr was noticed for samples with 3 wt% and 5 wt% Srferrite, probably because of increased charge carrier separation, where electrons migrate to BiOBr and holes to the SrFe 12 O 19 .…”

“…This leads to confusing results reported in different studies. For example, opposite charge transfers between the same components was claimed (e.g., BaFe 12 O 19 /g-C 3 N 4 [122,123]) or the oxidative role of • OH radicals in the presence of Ba-ferrite [78,81] was suggested, whereas other studies excluded such mechanisms [131,137]. Since water purification from organic pollutants remains the most investigated application of the magnetic photocatalysts, these details, as well as the possible factors that affect them, are considered as crucial for further studies to better understand the interactions between hexaferrites, other photocatalysts, and pollutants.…”

Aluminum Doping and Nanostructuring Enabled Designing of Magnetically Recoverable Hexaferrite Catalysts

“…SrFe 12 O 19 is a n-type semiconducting material and it has been used as a magnetic component to make composites with various metal oxide-based photocatalysts such as BiOBr and Bi 4 O 5 Br 2 . ,, Therefore, the composites act as catalysts as well as they are magnetic in nature that helps to recover the catalysts from the reaction mixture with a simple, inexpensive method of using a magnet. Thus, catalysts based on such a widely utilized permanent magnetic material may open up the new possibilities for integration into chemical and pharmaceutical industries, where the demand is continuously evolving for catalysts to eliminate or convert toxic and harmful chemical emissions into useful products.…”