Effect of cobalt doping on the electronic, optical and photocatalytic properties of TiO2

• Cobalt doped TiO2 was prepared by one step hydrothermal method under mild condition.
• The as-synthesized Co–TiO2 exhibits good visible light photocatalytic activity.
• The performance of TiO2 is enhanced by introducing impurity states in its band gap.

To extend the optical response to visible light region, cobalt doped TiO2 (Co-doped TiO2) with dopant concentration of 0.1 %–3.0 at % was synthesized by one step hydrothermal method without any post-heat treatment for crystallization. X-ray diffraction results confirm that all the doped and undoped TiO2 were composed of pure anatase phase with good crystallinity. The calculated grain size was ranged from 8.4 to 10.5 nm by Scherrer's method. The photocatalytic activities of the synthesized samples were evaluated by degradation of phenol under visible light irradiation. The Co-doped TiO2 sample with dopant concentration of 0.3 at% shows the highest degradation ratio. First principle calculations were performed and the results revealed that cobalt doping could realize its visible light response and enhance the photocatalytic performance of TiO2 by introducing impurity states in its band gap.

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