Role of Ni doping in surface carbon removal and photo catalytic activity of nano-structured TiO2 film

Nickel doped and undoped TiO2 films have been coated on cleaned glass substrates by sol-gel dip coating technique. Coated films were characterized by XRD, XPS, AFM and photocatalytic measurements after annealing at 500 °C. XRD studies confirmed the formation of anatase phase in both the films and crystallites size decreased from 10 to 6 nm in doped films with porous structure. From XPS observations, prominent decrease in C/Ti, increase in O/Ti and an enhancement of Ti3+ states at the film surface has been observed after Ni doping. The increase in O/Ti was related to partial replacement of Ti by Ni atoms. The photo degradation studies indicated the pseudo-first-order kinetics and an increase in kinetic constant by factor of two have been obtained in 10 M Ni doped films. The enhancement of photoactivity after doping was attributed to removal of surface carbon and increase in Ti3+ concentration.