Enhanced photocatalytic activity of BiFeO3 for water remediation via the addition of Ni2+

In this study, the photocatalytic activity of bismuth ferrite (BiFeO3) that is modified with Ni2+ to obtain BiFe2-xNixO3 (0 <= x <= 0.4 mol) is reported. The powders were synthesized by assisted high-energy ball milling. The X-ray diffraction (XRD) and Rietveld refinement demonstrate that Ni2+ cation is introduced in small quantities into the BiFeO3 crystal structure and occupies Fe3+ sites. The excess nickel transforms the BiFeO3 into sillenite (Bi25FeO40) and nickel ferrite (NiFe2O4) phases. The photocatalytic activities of the BiFe1-xNixO3 samples were compared to that of a commercial titanium dioxide (TiO2-P25) photocatalyst. Under irradiation in the UV-vis light spectrum, TiO2-P25 showed the highest photonic efficiency. The result was opposite when the samples were irradiated in the visible spectrum, where all the synthesized samples exhibited higher removal of crystal violet dye than those that were treated with the TiO2-P25. According to the results, all the modified materials are magnetically recoverable photocatalysts.