Preparation, characterisation and solar photoactivity of titania supported strontium ferrite nanocomposite photocatalyst

Enhanced ferromagnetic and visible light active titanium dioxide (TiO2) photocatalyst was synthesised by depositing a hard ferromagnet strontium ferrite (SrFe12O19) onto TiO2 via an effortless hydrothermal and poly-condensation method. The catalysts were characterised by X-ray diffraction (XRD), transmission electron microscope (TEM), energy dispersive X-ray spectroscopy (EDS), BET surface analysis, vibrating sample magnetometer (VSM), X-ray photon spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR) and UV-visible light spectroscopy analysis. The prepared nanocomposite photocatalyst exhibited physically a powerful ferromagnetic property with significant stability against the loss of its magnetic property (coercivity approximate to 2200G). The catalyst can be fluidised and recovered by an external magnetic field enhancing separation and mixing efficiency. Furthermore, it resulted in a reduced band gap (approximate to 2.3eV) which resulted in enhanced visible light absorption compared with unsupported TiO2. The photocatalytic activity was investigated by degrading a recalcitrant phenolic compound, viz., 2, 4-dichlorophenol (2,4-DCP) as model pollutant under different illuminance of daylight. Complete degradation of 2,4-DCP (50mg/L initial concentration in 0.25L) was achieved in 120min (supported photocatalyst) and 180min (unsupported TiO2) under higher illuminance of sunlight. Likewise under diffused sunlight, 100% degradation of 2,4-DCP was achieved in 240min for the supported TiO2, while 90% degradation could be achieved in 300min for the unsupported TiO2. The supported nanocomposite was recycled under a permanent magnetic field with a mass recovery of 98% and reused.