Synthesis and Multifunctional Evaluation of TiO₂ and ZnO Nanoparticles: Photocatalytic, Optical Sensing, and Environmental Remediation Applications

Metal oxide nanoparticles (MONPs) such as TiO₂ and ZnO are well-known for their diversefunctional properties and environmental compatibility. In this study, TiO₂ and ZnO nanoparticles weresynthesized via the sol-gel method and thoroughly characterized using Scanning Electron Microscopy(SEM), X-ray Diffraction (XRD), and UV-Visible spectroscopy to examine their morphological, structural,and optical features. The photocatalytic activity of the nanoparticles was evaluated by monitoring thedegradation of a model organic dye under UV light irradiation. In addition, their potential for opticalsensing was explored through band gap modulation and absorbance behavior, demonstrating sensitivity toexternal chemical environments. Furthermore, the nanoparticles exhibited significant adsorption capacitytoward dye molecules, indicating their utility in environmental remediation beyond photocatalysis. Thesefindings highlight the multifunctional nature of TiO₂ and ZnO nanoparticles, making them promisingcandidates for sustainable environmental technologies.