Magnetic and optical properties of green synthesized nickel ferrite nanoparticles and its application into photocatalysis

Spinel NiFe2O4 nanoparticles have been synthesized via hydrothermal route using Mangifera indica flower extract (MIFE) as a green surfactant and reducing agent. X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and transmission electron microscopy techniques have been used to determine the structure and morphology. The formation of single-phase, monodispersed NiFe2O4 with mixed morphology, the predominant shape being of equi-axed nanoparticles having an average particle size less than or similar to 45 nm, is observed. The thermal magnetization of as-synthesized NiFe2O4 nanoparticles shows ferromagnetic to paramagnetic phase transition at T (c) similar to 825 K. These nanoparticles show a very high saturation magnetization (M (s)) value of 55 emu g(-1) close to the bulk material and amongst the highest reported values for green synthesized NiFe(2)O4 nanoparticles. This material has a coercivity (H (c)) of 0.15 kOe and remanent magnetization (M (r)) of 8.5 emu g(-1). The as-synthesized NiFe2O4 nanoparticles show bandgap energy of 2.02 eV, derived from UV-vis absorption measurement, which is suitable for effective solar photocatalytic reactions. When exposed to sunlight in the presence of as-synthesized NiFe2O4 nanoparticles, 93% of MB-dye degradation is measured in 80 min, indicating excellent photocatalytic properties. Based on the as-synthesized NiFe2O4 nanoparticles' observed properties, the effectiveness of MIFE as an environmentally friendly surfactant, and the low-cost dye-degradation prospects of green synthesized NiFe2O4 nanoparticles are affirmed.