Photocatalytic activity of BiFeO 3 /ZnFe 2 O 4 nanocomposites under visible light irradiation.

Herein, BiFeO 3 /ZnFe 2 O 4 nanocomposites were synthesized via a glyoxylate precursor method using a two-pot approach. Phase evolution is investigated by X-ray diffraction and Raman spectroscopy, which confirm that no impurity phases are formed between BiFeO 3 and ZnFe 2 O 4 following calcination at 600 °C. The specific surface area characterized by N 2 adsorption-desorption isotherms decreases from 30.56 to 13.13 m 2 g -1 with the addition of zinc ferrite. In contrast, the magnetization increases from 0.28 to 1.8 emu g -1 with an increase in the amount of ZnFe 2 O 4 . The composites show strong absorption in the visible region with the optical band gap calculated from the Tauc's plot in the range from 2.17 to 2.22 eV, as measured by diffuse reflectance spectroscopy. Furthermore, the maximum efficiency for the photodegradation of methylene blue under visible light is displayed by the composite containing 25 wt% ZnFe 2 O 4 due to the synergic effect between BiFeO 3 and ZnFe 2 O 4 , as confirmed by photoluminescence spectroscopy.