In this study, TiO₂ nanoparticles were successfully synthesized using sol-gel technique by employing different mixing routes. The nanoparticles were characterized for field emission scanning electron microscopy, energy dispersive X-Ray spectroscopy, Fourier transformed infrared, Raman spectroscopy, x-ray diffraction and ultraviolet visible spectroscopy. It is apparent that different mixing sol-gel route significantly influenced the morphology, crystallite structure, particle and crystal size and band gap of TiO₂, under similar molar ratio. The differences in physicochemical and optical properties of synthesized TiO₂ greatly influenced its photocatalytic activity in reactive black 5 dye degradation. In overall, mixed crystal structures of anatase and rutile showed better photocatalytic activity for the degradation of reactive black 5 dye due to a narrower band gap, as opposed to single phase TiO₂.