In this study, niobium (Nb) and silver (Ag) codoped TiO2 (TNA) mesoporous nanoparticles were synthesised by sol-gel (TNA-SG) and hydrothermal (TNA-H) methods. The synthesized samples were calcined under an air atmosphere for 1 hour at 550°C. The prepared samples were characterised by X-ray diffraction (XRD), Fourier transformation infrared spectroscopy (FTIR), N2 adsorptiondesorption isotherms (BET-BJH), UV-Vis spectrophotometry, field emission scanning electron microscopy (FESEM) and highresolution transmission electron microscopy (HR-TEM). The results of X-ray analysis, the presence of anatase phases in the sol-gel method and the combination of anatase and rutile in the hydrothermal method was confirmed. The effect of synthesis method on the crystalline structure, specific surface area, pore size distribution, and photocatalytic activity of the synthesised samples was studied. The photocatalytic activity of the nanoparticles for the degradation of the methylene blue dye solution for the hydrothermal nanoparticles was better than the sol-gel method. The photocatalytic degradation efficiency of hydrothermal and sol-gel method was about 92.06% and 95.6%, respectively.
