BiFeO3/BiVO4 nanocomposite photocatalysts with highly enhanced photocatalytic activity for rhodamine B degradation under visible light irradiation
In this paper, the BiFeO3/BiVO4 nanocomposite photocatalysts were successfully synthesized by the homogeneous precipitation method followed with the hydrothermal method. The characteristics of as-prepared photocatalysts were measured by using X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM), Brunauer, Emmett and Teller (BET), Photoluminescence (PL) and UV-vis diffuse reflectance spectra (UV-vis DRS) techniques. The photocatalytic activity of rhodamine B (RhB) with the photocatalysts was estimated by the visible light irradiation. The experimental results were found that a mole ratio of 0.5:0.5 of BiFeO3:BiVO4 exhibited the highest photocatalytic performance as compared with other photocatalysts. More importantly, BiFeO3 decorated on the BiVO4 surface to form a composite, resulting in its large surface area and enhanced photoabsorption to the visible light regions. Moreover, it also was synergistic with the BiVO4 to hinder the rapid recombination of electron-hole pairs. The stability and recyclability of 0.5BiFeO3/0.5BiVO4 were also tested by five recycling runs, and the addition of the radical scavengers in the photodegradation process of RhB under visible light irradiation was detected through trapping experiments. The results were found that hydroxyl radicals (OH∙) and holes (h+) was the major active species, which had a considerable part of RhB degradation. The photocatalytic mechanism of BiFeO3/BiVO4 nanocomposite photocatalysts was also discussed.