Photocatalytic activity of magnetically recoverable MnFe₂O₄/g-C₃N₄/TiO₂ nanocomposite under simulated solar light irradiation

A magnetic nanocomposite composed of manganese ferrite (MnFe₂O₄), graphitic-carbon nitride (g-C₃N₄) and titanium dioxide-P25 (TiO₂) was synthesized via chemical impregnation method. The as-synthesized nanocomposite (MnFe₂O₄/g-C₃N₄/TiO₂) was characterized using X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), high resolution TEM (HR-TEM) elemental mapping, energy dispersive X-ray spectroscopy (EDX), UV-visible diffuse reflectance spectroscopy (UV-vis-DRS), photoluminescence (PL), B.E.T. surface area analysis, X-ray photo-electron spectroscopy and vibrating sample magnetometery (VSM) techniques. The band gap of TiO₂ was decreased after surface modification with MnFe₂O₄/g-C₃N₄. The photocatalytic activity was tested for the degradation of methyl orange (MO) dye as a model pollutant under simulated solar light irradiation. It was found that MnFe₂O₄/g-C₃N₄/TiO₂ displayed excellent photocatalytic activity than that of g-C₃N₄, MnFe₂O₄ and MnFe₂O₄/g-C₃N₄. The enhancement in the photocatalytic activity was ascribed to the synergism between TiO₂, g-C₃N₄ and MnFe₂O₄. VSM results revealed that ferromagnetism was retained in the nanocomposite (MnFe₂O₄/g-C₃N₄/TiO₂) and it could be easily removed using an external magnet after the photo-reaction. Besides, the durability and stability of magnetic nanocomposite was tested by recycling experiments.