Alcohothermal Synthesis and Characterization of Chitosan Supported Nickel Cobaltite Composite for Enhanced Photocatalytic and Antibacterial Activity

The transition metal oxide composites with biopolymer chitosan have captured the great interest of researchers for photocatalytic and antibacterial applications. Such composites enhance the photocatalytic degradation efficacy and inhibit bacterial growth effectively. In the present research, Nickel Cobaltite (NiCo₂O₄) and Chitosan Supported Nickel Cobaltite (Chitosan-NiCo₂O₄) composites were synthesized for the first time by employing alcohothermal method. Alcohothermal method was selected for its array of benefits including its capability to facilitate low-temperature synthesis, produce materials with controlled composition and morphology, reduce aggregation and promote good crystallinity. The synthesized composites were characterized by several techniques including XRD, FESEM, FTIR and UV-Vis spectroscopy. XRD pattern confirmed the formation of cubic spinel structure of NiCo₂O₄. FTIR analysis showed the stretching vibration mode of Ni-O and Co-O in NiCo₂O₄. FESEM image revealed nano-sheet like morphology with noticeable roughness and voids. The optical band gap of Chitosan-NiCo₂O₄ is narrower (1.37 eV) as compared to that of NiCo₂O₄ (1.27 eV). Chitosan-NiCo₂O₄ degraded the Methyl Blue (MB) dye up to 93% in 50 min when exposed to sunlight irradiation. After six cycles, Chitosan-NiCo₂O₄ retained its degradation efficiency up to 89% (with only 4% loss), demonstrating its good stability and reusability. This improvement is credited to the inclusion of chitosan which enhanced the surface area and porosity of the composite, which in turn exhibited good adsorbent behavior. Furthermore, Chitosan-NiCo₂O₄ exhibited superior antibacterial behavior compared to NiCo₂O₄ against both gram-negative and gram-positive bacteria.