Impact of Cu and La on the structural, morphological, magnetic, photocatalytic, and antibacterial traits of cobalt spinel nanoferrites

The multifunctional copper and lanthanum doped CoFe 2 O 4 nanoferrites of chemical formula, Co 1-x Cu x La y Fe 2-y O 4 , ( x = 0.0–0.04; y = 0.0–0.03) were fabricated via the sol-gel auto-combustion (SG) approach to investigate the optical, magnetic, microstructural, photocatalytic, and antibacterial traits. X-ray diffraction analysis verified the formation of a cubic phased structure for the synthesized materials with no additional impurities. The SEM pictures of CoFe 2 O 4 and Co 0.97 Cu 0.03 La 0.02 Fe 0.98 O 4 samples show the spherical shape like grains having a grain size of 90.98 and 62.74 nm. In the Raman spectra, five Raman active modes were seen in range of 200–800 cm -1 which gives a strong validation toward the spinel cubic symmetry. According to magnetic traits, a soft magnetic behavior in the values of saturation magnetization ( M s = 81.32–104.61 emu/g) and retentivity ( M r = 35.80–49.03 emu/g) with a large coercivity ( H c = 1394.52–1892.79 Oe) was found. With the Cu and La substitution, the band gap drops from 1.73 to 1.48 eV. Based on the photodegradation study, the doped ferrite nanomaterials performed better under the specific reaction conditions (catalysts dosage: 0.03g, dye dosage: 10 mgL -1 , pH: 4). The Co 0.96 Cu 0.04 La 0.03 Fe 0.97 O 4 nanoferrite shows the higher photocatalytic performance of 93.75% due to its smaller energy band gap. The photodegradation efficiency of CoFe 2 O 4 doped with Cu and La against the Congo red (CR) dye has increased from 87.08 to 93.75% in 60 min of natural sunlight irradiation. Throughout the 5 repeated reuse cycles, the catalyst efficacy did not noticeably decline. In contrast to the undoped CoFe 2 O 4 and doped Co 0.97 Cu 0.03 La 0.02 Fe 0.98 O 4 nanoferrites which exhibited no zone of inhibition (ZOI) for the Staphylococcus aureus , the developed Co 0.98 Cu 0.02 La 0.01 Fe 0.99 O 4 and Co 0.96 Cu 0.04 La 0.03 Fe 0.97 O 4 nanoferrites showed ZOI against the Staphylococcus aureus bacterial strain. With all excellent photodegradation, and antibacterial traits, the undoped and Cu/La doped cobalt nanoferrites works as a new door for environmental and biological applications.