Effect of Ni doping on the magnetic and photocatalytic properties of CoFe₂O₄ nanoparticles

The current study aimed to access photocatalytic degradation of methylene blue (MB) dye using undoped CoFe₂O₄, 2%, 4%, and 6% Ni-doped CoFe₂O₄ nanoparticles synthesized via chemical co-precipitation method. X-ray diffraction (XRD) was performed for structural analysis which confirmed the spinel cubic structure of the prepared nanoparticles. Scanning electron microscopy (SEM) was performed for surface and morphological study revealing the agglomeration of nanoparticles due to magnetic behavior of CoFe₂O₄ nanoparticles. UV–visible absorption spectroscopy was performed, and bandgap was calculated using tauc plot, which revealed that bandgap increases with increasing Ni doping concentration in CoFe₂O₄ nanoparticles. Vibrating-sample magnetometry (VSM) was performed to study the magnetic behavior of synthesized nanoparticles, and it was observed that the saturation magnetization value is higher for 2% Ni-doped CoFe₂O₄ nanoparticles. Photocatalytic activities for the prepared samples were analyzed for MB as an organic pollutant. 2% Ni-doped sample possessed greater efficiency of 67% in degrading the organic pollutant (MB), whereas pure cobalt ferrite possessed 51.6%, respectively. This superior Photocatalytic performance of 2% Ni-doped cobalt ferrite nanoparticles may be associated with introduction of localized defect states that may lead to trapping of electrons to prevent their recombination and enhanced visible light absorption. These findings imply the potential of Ni-doped CoFe₂O₄ photocatalysts for the degradation of organic pollutants in wastewater.