Structural and optical analysis coupled with photocatalytic evaluation of WO₃/TiO2 nanocomposites for enhanced dye degradation and antibacterial activity

In this work, a WO 3 / TiO 2 nanocomposite was successfully fabricated through an ex-situ assembly of pre-synthesized WO 3 and TiO 2 nanoparticles, followed by calcination. The synthesized nanocomposite was systematically investigated to understand its morphological, structural, and optical properties. X-ray diffraction technique confirmed the development of a well-crystallized heterostructure, while high-resolution transmission electron microscopy showed uniformly distributed nanoparticles with an average particle size of approximately 32 nm. Optical properties were estimated using UV–visible diffuse reflectance spectroscopy, which indicated a reduced band gap energy of ~ 2.14 eV, suggesting enhanced natural sunlight absorption ability. Photocatalytic activity of WO 3 / TiO 2 nanocomposite was examined under natural sunlight irradiation using organic dyes as model pollutants. Notably, a high degradation efficiency of approximately 91% was achieved for Congo red dye, demonstrating the superior photocatalytic activity of the nanocomposite. The creation of an efficient WO 3 /TiO 2 heterojunction, which permits efficient charge transfer, suppresses the recombination of photogenerated electron–hole pairs, and encourages improved migration and separation of charge carriers, is the main cause of the improved performance. These synergistic effects significantly enhance the photocatalytic efficiency under solar illumination, highlighting the potential of WO 3 /TiO 2 nanocomposites for environmental remediation and wastewater treatment applications.