Surfactant-mediated wet-chemical synthesis of magnetically retrievable and structurally tuned cobalt ferrite: A visible light-triggered photocatalyst for the abatement of azo dye

The present study involved the synthesis of pristine cobalt ferrite (CoFe₂O₄, CF) and magnesium and gallium doped cobalt ferrite (Co_1−xMg_xFe_2−yGa_yO₄, MGCF) photocatalysts using a wet chemical approach. Using a photocatalytic approach, the prepared photocatalyst was successfully utilized to degrade the Crystal violet dye (Azo dye) from industrial effluents. The effects of Mg/Ga doping on pristine CoFe₂O₄ and doped Co_1−xMg_xFe_2−yGa_yO₄ nanoparticles were examined using physical and electro-chemical methods such as XRD, FESEM, FTIR, IV measurement, and UV–Vis spectroscopy. X-ray diffraction study confirmed the synthesis of CoFe₂O₄ spinel ferrite exhibiting a cubic crystal structure with the Fd3m¯ space group. Photoluminescence studies indicate that dopants can reduce the e⁻-h⁺ recombination rate and enhance the photocatalytic efficiency of MGCF nanomaterials. In terms of visible-light harvesting, the optical investigation proposed the MGCF sample with a band gap value of 2.46 eV. In this study, the MGCF sample exhibits superior photocatalytic efficiency (100 %) in the degradation of crystal violet dye compared with CoFe₂O₄ (76.7 %) in 64 min under visible-light irradiation. Moreover, scavenging and cycling experiments showed the active species (h⁺ and O₂^*−) accountable for the dye degradation and the sufficient stability of MGCF up to five cycles, respectively. This work presents a novel method for optimizing spinel ferrites’ structural characteristics and other key features through the co-doping process, assuring their efficiency in treating contaminated water.