BiFeO(3)-Black TiO(2) Composite as a Visible Light Active Photocatalyst for the Degradation of Methylene Blue

[Image: see text] The application of a novel BiFeO(3) (BFO)-black TiO(2) (BTO) composite (called BFOT) as a photocatalyst for the degradation of methylene blue is reported. The p–n heterojunction photocatalyst was synthesized for the first time through microwave-assisted co-precipitation synthesis to change the molar ratio of BTO in BiFeO(3) to increase the photocatalytic efficiency of the BiFeO(3) photocatalyst. The UV–visible properties of p–n heterostructures showed excellent absorption of visible light and reduced electron–hole recombination properties compared to the pure-phase BFO. Photocatalytic studies on BFOT10, BFOT20, and BFOT30 have shown that they decompose methylene blue (MB) in sunlight better than pure-phase BFO in 70 min. The BFOT30 photocatalyst was the most effective at reducing MB when exposed to visible light (97%). Magnetic studies have shown that BTO is diamagnetic, and the BFOT10 photocatalyst exhibits a very weak antiferromagnetic behavior, whereas BFOT20 and BFO30 show diamagnetic behavior. This study confirms that the catalyst has poor stability and weak magnetic recovery properties due to the non-magnetic phase BTO in the BFO.