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.