Magnetic nanocomposite based on nickel-bismuth ferrite for photocatalytic degradation of organic dyes

Multiferroics are class of materials that have ferroelectric, ferromagnetic or antiferromagnetic properties [1].The one of the most largely studied multiferroic materials over the last decade is about bismuth-ferrite (BiFeO3) because it is the only single phase material that can act both as antiferromagnetic and ferroelectric at room temperature [2].The addition of Ni, Zn, Mn, Ti, Zr etc. to BiFeO3 improves the ferroelectric properties [3, 4]. Among the many atoms, Ni is the best candidate in improving the ferromagnetic properties. In addition, the Ni substitution is also found to be effective for enhancing the ferroelectricity in BiFeO3 [3-5]. It has been indicated that BiFeO3 nanoparticles have a band gap in the range of 2.5–3.0 eV. [5, 6]. In the present study, Ni-Bi-Fe magnetic photocatalysts were successfully synthesized by the sol–gel technique using nickel, bismuth and iron nitrate powders as precursor. Synthesized photocatalyst exhibited excellent catalytic activity for the degradation of Congo red and reactive blue 222 as model dyes in water under visible irradiation. The results showed that degradation efficiency depend on amount of catalyst, initial dye concentration, and irradiation time. The structural and properties of The as-synthesized photocatalyst was characterized by different techniques including X-ray diffraction (XRD), Scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy, energy dispersive analysis of X-ray (EDAX) and UV-vis spectroscopy (UV-vis). The photocatalyst could easily be separated from the reaction mixture due to the it’s magnetic properties and remain active.