Metal oxide nanocomposites have gained significant attention due to their unique physicochemical properties and applications in biomedicine, catalysis, sensing, and environmental remediation. Among them, zinc oxide (ZnO) nanoparticles (NPs) are widely studied, and functionalization with thiosemicarbazide (TSC) derivatives enhances their stability, reactivity, solubility, and biocompatibility. Ultrasonic-assisted synthesis offers an eco-friendly approach, enabling rapid nucleation, uniform dispersion, and controlled particle size while promoting efficient ligand coordination. Nanocomposites are typically characterized using various spectroscopic techniques, which confirm successful functionalization. This review highlights synthesis strategies, characterization techniques, and applications of ligand-functionalized metal oxide nanocomposites in environmental, catalytic, and biological fields.
