The photocatalytic degradation of methylene blue (MB) has been investigated under visible light irradiation with an incandescent light bulb using chromium doped TiO2 nanoparticles. Cr–TiO2 photocatalysts were successfully synthesized by sol–gel method at room temperature and characterized by X-ray diffraction (XRD), UV–Vis diffuse reflectance spectroscopy (UV–Vis DRS), Raman spectroscopy, Transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy. The band gap energy of the nanoparticles were estimated using UV– Vis DRS technique. With increasing Cr3? cations content into TiO2 host lattice, the optical absorption band tuned in the visible region. XRD and TEM results reveal uniform and crystalline anatase TiO2 nanoparticles. The photodegradation of MB indicated that the photocatalytic activity of pure TiO2 nanoparticles increased with increasing Cr3? cations concentration.
