TiO₂–CeO₂ nanocomposites were successfully synthesized using the sol–gel method, which is a flexible, cost-effective, and widely adopted chemical synthesis technique known for producing highly homogeneous and ultra-pure nanostructured materials. The sol–gel process allows precise control over composition, particle size, and microstructure, making it particularly suitable for preparing mixed metal oxide nanocomposites. In recent years, the TiO₂–CeO₂ system has attracted considerable research interest due to its synergistic physicochemical properties, which enhance its performance in applications such as photocatalysis, environmental remediation, gas sensing, and energy-related technologies. In the present study, titanium isopropoxide and cerium nitrate were used as precursor materials for titanium and cerium sources, respectively. These precursors were hydrolyzed under carefully controlled pH and temperature conditions to obtain TiO₂–CeO₂ nanocomposites with varying molar ratios of TiO₂ and CeO₂. Controlled hydrolysis and condensation reactions ensured uniform distribution of CeO₂ within the TiO₂ matrix. The resulting sols gradually transformed into gels, which were subsequently aged to improve network formation and structural stability. X-ray diffraction (XRD) analysis confirmed the successful formation of anatase TiO₂ and fluorite-structured CeO₂ phases. The absence of impurity peaks in the diffraction patterns indicated high phase purity and effective incorporation of CeO₂ into the TiO₂ lattice. The crystallite size of the nanocomposites was found to vary between 10 and 25 nm, depending on the CeO₂ content and the calcination temperature, suggesting that cerium doping influenced crystal growth and inhibited particle agglomeration. Fourier-transform infrared spectroscopy (FTIR) was employed to analyze the chemical bonding and functional groups present in the nanocomposites. The FTIR spectra exhibited characteristic metal–oxygen stretching vibrations corresponding to Ti–O–Ti, Ce–O, and Ti–O–Ce bonds. These features confirmed strong chemical interactions and successful coupling between TiO₂ and CeO₂ within the nanocomposite structure. Field emission scanning electron microscopy (FE-SEM) revealed nearly spherical nanoparticles with relatively uniform size distribution and reduced agglomeration. UV–visible diffuse reflectance spectroscopy (UV–Vis DRS) indicated enhanced optical absorption and band-gap modification due to CeO₂ incorporation.

Keywords: TiO₂–CeO₂; Nanocomposites; Sol Gel; Gas Sensor; Nanocrystal;