Fabrication and photocatalytic performance of C, N, F-tridoped TiO2 nanotubes

By impregnating the thermal stable TiO2 nanotubes (C/TiO2NTs) in NH4F solution with different concentrations and subsequent calcination treatment at different temperatures, C, N, F-tridoped TiO2 nanotubes (C, N, F/TiO2NTs) were prepared. XRD, XPS, TEM, TG-DTG, UV-vis and nitrogen adsorption were used to and characterize the prepared materials. The influences of dopants, calcination temperature and NH4F concentration on the catalytic performances of C, N, F/TiO2NTs under UV light and simulated sunlight were investigated by using methyl orange solution as simulant wastewater. Obtained results indicated that the C, N, F/TiO2NTs exhibited higher photocatalytic activity than the C-doped or N, F-codoped ones, and the C, N, F/TiO2NTs showed the best photocatalytic performance when they were calcinated at 300 degrees C and impregnated by 1 wt.% NH4F solution. The electronic density of states (DOS) analysis results implied that the C, N, F-tridoping could improve the electronic transition and narrow the band gap of anatase TiO2, and resulted in improved photocatalytic performance. The synergistic effects of the three dopants were also discussed.