Defect engineered Li₂O-ZrO₂-NiO multi-metal oxide nanocomposite exhibiting enhanced structural properties optical behavior and cytotoxic activity.

Abstract

Multi-metal oxide nanocomposites have attracted considerable attention due to their tunable physicochemical properties and multifunctional applications. In the present study, a Li2O-ZrO2-NiO multi-metal oxide nanocomposite was successfully synthesized via a facile co-precipitation route followed by controlled thermal treatment. The structural and compositional features of the material were systematically characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), energy-dispersive X-ray analysis (EDAX), UV-Visible spectroscopy, and thermal analysis (TGA-DTG-DSC). XRD results confirmed the formation of crystalline ZrO2 and NiO phases with nanoscale dimensions, while FT-IR spectra evidenced the formation of characteristic metal-oxygen bonds. The nanocomposite exhibited broad optical absorption spanning the ultraviolet to visible regions (250-950 nm), attributed to defect states and oxygen vacancies induced by lithium incorporation. The thermal stability of the composite was established, and the choice of 900 °C as the calcination temperature for phase-pure oxides was justified by thermal analysis (TGA-DTG-DSC), which exhibited that precursor decomposition and carbonate-to-oxide phase transformation were nearly complete above 680 °C. Elemental analysis confirmed the presence of constituent metals with high purity. The biological activity of the synthesized nanocomposite was evaluated against HepG2 cells using the MTT assay, demonstrating a pronounced concentration-dependent cytotoxicity with an IC50 value of approximately 10 µg/mL. Morphological observations further revealed significant cellular damage, including shrinkage and loss of adhesion, suggesting apoptosis-mediated cell death. The enhanced performance of the nanocomposite can be attributed to synergistic interactions among Li, Zr, and Ni oxides, as well as defect-mediated electronic modifications that promote the generation of reactive oxygen species. Overall, the results highlighted the potential of the Li2O-ZrO2-NiO multi-metal oxide nanocomposite as a promising candidate for advanced catalytic and anticancer applications, offering a simple synthesis strategy and improved functional properties.

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