Preparation of Fe(III) and Ho(III) co-doped TiO2 films loaded on activated carbon fibers and their photocatalytic activities

Fe(III) and Ho(III) co-doped TiO2 films and un-doped TiO2 films loaded on activated carbon fibers (ACF) were prepared by sol–gel-adsorption method. The detailed surface characteristics of the loaded samples and their photocatalytic activities for the discoloration of methyl orange (MO) in water were carried out. The results showed that photocatalyst films were immobilized on the surface of ACF successfully, and the co-doping with Fe(III) and Ho(III) could restrain the forming of crack in TiO2 films. Results also showed that MO could be removed rapidly from water by the loaded samples under UV irradiation because of the synergistic effects of two factors: absorption of ACF and photocatalytic degradation of photocatalyst films. The sample of Fe(III) and Ho(III) co-doped TiO2 films calcined at 600 °C exhibited better and stabler photocatalytic activity than that sintered at 800 °C. The discolored ratio of MO was maintained at above 99% without any decline when the sample was used repeatedly, even at the fourth cycle.