摘要:Nitrogen (N) doped TiO2 were synthesized by thermal decomposition of the mixture of TiO2 and urea at 500 C. Optical and structural properties of N doped TiO2 were investigated by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, UV–visible diffusion reflectance spectroscopy (UV-DRS) and scanning electron microscopic (SEM) techniques. XRD showed that anatase phase was converted into rutile phase while increasing the content of urea. FTIR studies revealed that number of hydroxyl group on TiO2 surface decreases with increasing the concentration of nitrogen. SEM studies were carried out for the morphological features and size of TiO2 particles. DRS data showed a red shift in absorption edge and band gap become narrower while increasing the concentration of nitrogen. The photocatalytic activity was evaluated for photodegradation of indigo carmine dye under UV light irradiation. Keywords : Indigo carmine dye ; Nitrogen ; Photo catalytic activity ; Titanium dioxide.