Magnetically separable electrospun BiFeO3/BiVO4 heterojunction nanofibers and the visible-light photocatalytic performance

Abstract

In this paper, a novel architecture of magnetically separable BiFeO3 nanofibers were prepared by electrospinning method, and BiFeO3/BiVO4 heterojunction photocatalyst was successfully synthesized by hydrothermal method. Their structures and optical properties were characterized by X-ray diffraction, scanning electron microscopy, field emission transmission electron microscopy, the Brunner-Emmett-Teller surface areas, X-ray photoelectron spectroscopy, vibrating sample magnetometer, photoluminescence spectrum and UV–visible absorption spectroscopy. The degradation of rhodamine B by visible light irradiation for 180 min showed that the molar ratio of BiFeO3:BiVO4 was 2:1, which showed higher photocatalytic performance. The high surface area of BiFeO3:BiVO4 nanofiber heterojunction may provide more active sites for the photocatalytic reaction and promote the spatial separation of photogenerated charge, and thus show higher visible light catalytic efficiency, which is 9.5 times and 3.6 times of the single component of BiFeO3 and BiVO4 respectively. In addition, BiFeO3:BiVO4 heterojunction nanofibers are ferromagnetic and can be separated from solutions under external magnetic fields. The photocatalytic activity of the BiFeO3:BiVO4 heterojunction did not decrease significantly after five catalytic experiments, indicating that BiFeO3:BiVO4 heterojunction is stable. Free radical capture experiments show that ·OH and h+ were the main groups involved in redox reactions. Proposed photocatalyst can efficiently degrade environmental pollutants Rhodamine B under visible-light, and is easy to recover, which is expected to be used in industrial wastewater treatment.