SYNTHESIS, CHARACTERIZATION, AND PHOTOCATALYTIC APPLICATIONS OF METAL-DOPED TIO₂ NANOPARTICLES FOR SOLAR-DRIVEN WATER PURIFICATION

This study presents a comprehensive investigation into the synthesis, characterization, and photocatalytic performance of metal-doped titanium dioxide (TiO₂) nanoparticles for solar-driven water purification. Addressing the global challenge of water pollution, the research focuses on enhancing TiO₂’s photocatalytic efficiency under visible light by doping with silver (Ag), copper (Cu), and iron (Fe). The nanoparticles were synthesized via the sol-gel method, a cost-effective and scalable approach, and characterized using advanced techniques including X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-Vis diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), and Brunauer-Emmett-Teller (BET) surface area analysis. These methods revealed the structural, morphological, optical, and surface properties of the catalysts, confirming successful dopant incorporation, reduced bandgaps (2.80–3.00 eV), and increased surface areas (74–85 m²/g) compared to undoped TiO₂ (3.20 eV, 65 m²/g). Photocatalytic performance was evaluated through the degradation of methylene blue (MB) under simulated solar irradiation, with Ag-TiO₂ achieving the highest efficiency (92% degradation in 120 minutes), followed by Cu-TiO₂ (85%) and Fe-TiO₂ (80%), significantly outperforming undoped TiO₂ (65%). The enhanced performance is attributed to bandgap narrowing, improved charge separation, and, in the case of Ag-TiO₂, surface plasmon resonance effects. The catalysts demonstrated excellent stability and reusability over multiple cycles, making them viable for practical water treatment applications. Supported by detailed figures and tables illustrating XRD patterns, SEM/TEM images, optical properties, and degradation kinetics, this work highlights the potential of metal-doped TiO₂ as a sustainable solution for addressing water pollution using solar energy. The findings pave the way for future research into optimized doping strategies and real-world applications in complex water matrices.