The surface Reactivity of Silver Nanoparticles Doped with TiO 2 Nanorod like crystals for enhancing Photocatalytic Degradation of harmful water pollutants under visible - light irradiations

A novel photocatalyst was developed through the synthesis of TiO₂ nanoparticles followed by their transformation into TiO₂ nanorod-like crystals via a hydrothermal method. The surface properties of this TiO₂ nanorod like crystals (TiO₂ NRCs) were further enhanced by decorating them with Ag nanoparticles using a chemical reduction approach, resulting in a significant improvement in photocatalytic performance of TiO₂–Ag NRCs. To elucidate the origin of this enhancement, a comprehensive investigation of the structural, optical, vibrational, and electrochemical properties was carried out using a range of advanced characterization techniques, including high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), diffuse reflectance spectroscopy (DRS), photoluminescence spectroscopy (PL), electrochemical impedance spectroscopy (EIS), Fourier transform infrared spectroscopy (FTIR), UV–visible spectroscopy, and Raman spectroscopy. HRTEM analysis confirmed the successful formation of heterojunctions within the photocatalyst, revealing the intimate interfacial contact and uniform decoration of Ag nanoparticles on the surface of TiO₂ nanorod like crystals. XRD patterns demonstrated the highly crystalline nature of the synthesized materials, while EIS measurements indicated enhanced separation and transport of photogenerated charge carriers. The improved charge dynamics are attributed to the efficient transfer of electrons from the conduction band of TiO₂ to Ag nanoparticles, which suppresses electron–hole recombination and prolongs the lifetime of holes within the TiO₂ NRCs. The photocatalytic activity of the TiO₂–Ag NRCs was systematically evaluated and compared with that of pristine TiO₂ nanoparticles through the degradation of methylene blue dye in an aqueous medium, monitored using UV–visible spectroscopy. The one-dimensional TiO₂–Ag nanorod-like crystals exhibited superior photocatalytic efficiency, achieving an exceptional methylene blue degradation efficiency of 99.7%. These results highlight the remarkable potential of TiO₂–Ag NRCs as highly efficient photocatalysts for the removal of organic pollutants and their promising applicability in addressing serious environmental water contamination challenges.