Magnetic composite photocatalyst ZnFe2O4/BiVO4: synthesis, characterization, and visible-light photocatalytic activity

Abstract

Magnetic composite ZnFe₂O₄/BiVO₄ was successfully synthesized by the one-step chemical coprecipitation method. The photocatalytic activity of BiVO₄ was improved by doping ZnFe₂O₄ that possessed a narrow band gap, which enabled the ZnFe₂O₄/BiVO₄ composite to show increased visible-light absorption and further generate more photo-produced electrons than pure BiVO₄. The experimental results showed that the photocatalytic ability of the composite was better than that of pure BiVO₄ under visible light irradiation. The n-type ZnFe₂O₄ nanoparticles were uniformly distributed on the surface of n-type BiVO₄, leading to the formation of n–n-type heterogeneous structures in the composite system. Since CB and VB potentials of ZnFe₂O₄ and BiVO₄ were differential, the photo-produced electrons and holes would migrate to a position at a relatively positive potential and a relatively negative potential, respectively, which enhanced the separation efficiency between photo-produced electrons and holes and thus further contributed to the enhancement of photocatalytic activity.