Influence of Lanthanum‐doping on photocatalytic activity of magnetic BiFeO3 nanocrystals for sunlight driven degradation of metachrome yellow

In the present work, the structural and photocatalytic activity of BiFeO3 (BFO) and Lanthanum doped BiFeO3 (LBFO; La0.2Bi0.8FeO3) nanocrystals (NCs) towards photodegradation of Metachrome Yellow dye were examined, hitherto unreported in the literature. The bismuth ferrite samples with a prominent rhombohedral phase at room temperature were prepared by sol-gel method, and investigated using multiple structural and spectroscopic tools. La doped BFO was found to be superior in terms of phase formation, photoluminescence quenching and visible light absorption. Further, La doped sample showed higher photodegradation efficiency of 71% compared to 50% by pure BFO NCs for Metachrome Yellow under natural sunlight. The enhanced photocatalytic ability of La doped BFO could be attributed to the increased polarization in the multiferroic oxide that promoted charge separation, besides the small bandgap well into the visible light region of the spectrum and the increased surface hydroxyl groups aiding the redox photodegradation reactions. Vibrating sample magnetometer studies of BFO and LBFO NCs revealed ferrimagnetic nature for the nanomaterials making it a potential photocatalyst for practical applications, as it could be magnetically separated post usage in waterbodies.