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

Taiping Xie,Longjun Xu,Yuanzhen Lu,Xiuyu Yin,Jun Yang,Jiao Hu,Songli Liu,Jiankang Wang,Chenglun Liu,Yuan Peng

doi:10.3390/nano9050735

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.

Highlights

Throughout the last few years, semiconductor photocatalysts, which can utilize the clean, renewable, and most accessible solar energy, have attracted more and more attention in the material science field [1,2]
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A primthaerRyhaBnadleygsrisadoafttihoenpuhnodteordUegVrairdratdioiantiroenv.ealed that BOB/SFO-5 was the most efficient in the Rhodamine B (RhB) degradation under UV irradiation. 3.1

Summary

Introduction

Throughout the last few years, semiconductor photocatalysts, which can utilize the clean, renewable, and most accessible solar energy, have attracted more and more attention in the material science field [1,2]. The Eg of BiOBr is 2.8 eV, leading to a low absorption ability of visible light and a high recombination rate of photo-induced electron-hole pairs [12,13]. Visible light absorption was enhanced by compositing SrFe12O19, involving the low band gap energy and resulting in quick charge separation and increased photocatalytic ability. Magnetic nanosheet BiOBr/SrFe12O19 (BOB/SFO-5) was prepared using a reasonable fabrication method, and the corresponding photocatalytic property was investigated under visible light and UV-LED (390–410 nm). The photocatalytic mechanism assisted by a magnetic field has been further discussed in this research. These results provide important concepts concerning the synthesis method, and pave the way for the industrial application of magnetic photocatalysts

Experimental Section

Material Characterization

Results and Discussion

Magnetic Property

Photocatalytic Mechanism

Conclusions