Enhanced photocatalytic activity of C-N-codoped TiO2 films prepared via an organic-free approach

An organic-free sol-gel method was developed to synthesize crack-free, high surface roughness and visible-light-active C-N-codoped TiO2 films. These films were subsequently evaluated for its photodegradation efficient using stearic acid as the model pollutant compound. The current approach avoids the use of hazardous organic solvents and employs carbon black as the carbon source as well as a template to increase the surface roughness. The presence of carbon and nitrogen species in TiO2 was studied and discussed. The concentrations of carbon and nitrogen dopants in the TiO2 films were affected by calcination temperature and the concentration of carbon black. Optimal visible light photocatalytic activity was observed for C-N-codoped TiO2 film at 10.0 wt.% C, which was more than double that of the N-doped TiO2 film. The enhancement in visible light photocatalytic activities of the C-N-codoped TiO2 films was attributed to the synergistic effects of carbon and nitrogen dopants, and high surface roughness of the prepared films.