Novel Magnetically Separable BiVO 4 /Fe 3 O 4 Photocatalyst: Synthesis and Photocatalytic Performance under Visible-light Irradiation

Abstract Novel magnetically separable BiVO 4 /Fe 3 O 4 visible-light-driven photocatalysts were successfully fabricated, in which Fe 3 O 4 was coated on the surface of BiVO 4 particles. The samples were characterized by means of XRD, SEM, EDS, UV–vis DRS, XPS, PL, FT-IR techniques. The results showed that the photocatalytic activity of BiVO 4 /Fe 3 O 4 photocatalysts under visible-light illumination was higher than that of pure BiVO 4 owing to the narrow band gap energy and delayed electron-hole recombination. Moreover, the mass fraction of Fe 3 O 4 had considerable effect on the photocatalytic activity of BiVO 4 /Fe 3 O 4 . Among them, BiVO 4 /30% Fe 3 O 4 composite exhibited superior activity, which made the degradation rate of Acid Red B reach to 97.6% after 40 min visible-light illumination. The degradation reaction accorded with first-order reaction kinetics equation. The rate constant of dye degradation reaction using BiVO 4 /30% Fe 3 O 4 as photocatalyst was about 2.19 times of pure BiVO 4 . Furthermore, a photocatalytic degradation mechanism was proposed on the basis of IR, XRD and PL analysis, and the introduction of the scavengers for the reactive species. More importantly, the magnetic properties of BiVO 4 /Fe 3 O 4 composite were measured and its reusability was also investigated after five successive runs applying an external magnetic field.