Magnetically separable NiFe2O4 nanoparticles: synthesis and photocatalytic activity

Current research addresses the successful development of magnetic NiFe 2 O 4 nanoparticles (NPs) by green method using cabbage ( Brassica oleracea L.) leaf extract as a capping agent. Obtained NiFe 2 O 4 NPs were calcined at 500, 600, and 700 °C for characterization and acted as photocatalyst. The NiFe 2 O 4 NPs are crystalline in nature with FCC cubic spinel structure. The XPS analysis confirmed the oxidation states of Ni 2+ and Fe 3+ , respectively. Prepared NiFe 2 O 4 NPs are in a spherical shape with a particle size of 10–12 nm is confirmed by SEM. FT-IR spectrum exhibits major bands of phytocompounds and Fe–O. The band gap energy of NiFe 2 O 4 is observed around 1.76 eV. Super-paramagnetic nature of NiFe 2 O 4 is observed by VSM and the saturation magnetization is around 20 emu/g. Using NiFe 2 O 4 NPs as a photocatalyst accomplished 94% photodegradation of Methyl Orange (MO) under UV–Vis. light (max-365 nm) within 135 min with 1.5 g/dm 3 photocatalyst loading. NiFe 2 O 4 NPs are easily separable by a bar magnet; hence the small nanoparticles can separate for reuse. Also, there is no significant change in photodegradation efficiency after time that indicates a photocatalyst is photostable and reusable.