Intermediate state created by dopant ions (Mn, Co and Zr) into TiO₂ nanoparticles for degradation of dyes under visible light

To expand the absorption of pure nanosized TiO₂ to the visible light range for improving the photocatalytic efficiency necessary for industrial application, the way of doping different transition metals such as Mn, Co and Zr into TiO₂ was done by sol-gel synthesis method. The X-ray diffraction studies were identified that the metal doped TiO₂ and undoped TiO₂ samples have the same tetragonal structure with pure anatase phase. Obviously, the crystallite size is smaller for the doped materials than that of pure TiO₂ sample. The characteristic FE-SEM images revealed well distributed spherical shaped particles. The dopant materials induced significant changes in the surface area of TiO₂ which was confirmed by Brunauer Emmet Teller method. The absorption edge of doped TiO₂ is at a higher wavelength that corresponds to red region, because of the formation of intermediate states in the doped metal ions into TiO₂ sites. Moreover, for the photocatalytic degradation of MB and MO dyes, the prepared catalysts were tested under both UV and visible light irradiation. The observation confirms that among all the other samples, Mn doped TiO₂ shows amazing photocatalytic performance in visible light due to its smaller crystallite size, large surface area and lower band gap.