Multifunctional Ce⁺³ doped nickel-cobalt mixed ferrites via co-precipitation method for photocatalytic and antibacterial activity

The overuse of industrial dyes and anti-bacterial drugs are destroying fresh water reservoirs and making bacteria more resistant, respectively. To sort out these problems, we have synthesized Cerium doped Nickel-Cobalt mixed ferrites (Ce-@NCMF) with chemical composition [Ni0.4Co0.6CexFe2-xO4 (where x = 0.00, 0.10, 0.15, 0.20 and 0.25)] via co-precipitation method. Influence of cerium doping on the structural, optical, electrical, magnetic, photocatalytic and anti-bacterial properties of Ce-@NCMF studied. Powder x-ray diffraction analysis (PXRD) confirmed the synthesis of Ce-@NCMF. Decrease of crystallite size from 29.71 to 24.95 nm was observed with increase in dopant concentration. Tauc's plot indicated the decrease of energy bandgap from 2.10 to 1.89 eV with increase in dopant concentration, which revealed the absorption of light in visible region to generate electron-hole pairs for photocatalytic applications. FTIR spectra indicated the presence of M-O bonds as major functional group present in Ce-@NCMF. Electrical properties demonstrated the prominent increase of electrical conductivity with increase of Ce-doping. VSM analysis was performed to analyse the magnetic properties of materials and showed prominent decrease in saturation magnetization value from 84.66 to 19.85 emu g-1. Owing to optical bandgap in the visible region, all the synthesized samples were evaluated for their photocatalytic potential for the degradation of methylene blue. Ce-@NCMF at x = 25% dopant value showed maximum degradation efficiency (95%) under sunlight irradiation of 90 min. Kinetic studies of dye degradation followed pseudo-1st order kinetics with maximum rate constant (k) value of 2.78x10-2 min-1. Antibacterial activity results showed the bioactive nature of Ce-@NCMF against all strains of bacteria in consistent with the crystallite size of samples. Smallest crystallite size Ce-@NCMF were found most active against gram-negative bacterial strains.