A step-wise synthetic method has been developed for the synthesis of multifunctional, magnetic luminescent nanocomposites with Fe 3 O 4 nanospheres as the core encapsulated in silica and europium-doped sodium lutetium fluoride (NaLuF 4 :Eu 3+) as the shell. X-ray powder diffraction (XRPD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS), photoluminescence (PL), kinetics of luminescence decay and magnetic studies were used to characterize the structural, optical and magnetic properties of these nanospheres. SEM and TEM images define their spherical morphology with average crystallite size in the range of 90-180 nm. Ultraviolet excited photoluminescent properties of Eu 3+ doped Fe 3 O 4 @SiO 2 @NaLuF 4 nanospheres were investigated and impact of doping has been explored. Eu 3+ as dopant ion induces highly efficient luminescence with average lifetime value of 6.235 ns. Fe 3 O 4 magnetic core exhibits super-paramagnetic behavior at room temperature.

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A facile approach has been devised for the preparation of magnetic NiFe 2 O 4 photocatalyst (NiFe 2 O 4 -NG) supported on nitrogen doped graphene (NG). The NiFe 2 O 4 -NG composite was synthesized by one step hydrothermal method. The nanocomposite catalyst was characterized by Powder X-ray diffraction (PXRD), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), Ultraviolet-visible spectroscopy (UV-Vis) and Vibrating sample magnetometry (VSM). It is found that the combination of NiFe 2 O 4 nanoparticles with nitrogen-doped graphene sheets converts NiFe 2 O 4 into a good catalyst for methylene blue (MB) dye degradation by irradiation of visible light. The catalytic activity under visible light irradiation is assigned to extensive movement of photogenerated electron from NiFe 2 O 4 to the conduction band of the reduced NG, effectively blocking direct recombination of electrons and holes. The NiFe 2 O 4 nanoparticles alone have efficient magnetic property, so can be used for magnetic separation in the solution without additional magnetic support.

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