Visible light-driven binary dyes synergic degradation by iodine-doped TiO2 nanocrystal film

We report synergistic degradation of fluorescein sodium/rhodamine B or eosin Y/rhodamine B using iodine-doped TiO2 nanocrystal film (I-TNC) under visible irradiation. The fabricated I-TNC was characterized by SEM, EDS and reflectance spectra. The degradation results showed that when Flu or EO was introduced to I-TNC/RhB system, the degradation ratio of RhB was significantly enhanced, with an eight-fold or five-fold improvement compared with that in I-TNC/RhB system free of sensitizer. The photocatalytic improvement may be explained by the mutually sensitization of binary dyes and narrowed bandgap caused by doping. Active oxygen species were evidenced to be involved in the synergic degradation.

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► Visible-driven binary dyes synergetic degradation by I-doped TiO2 film was assayed.
► I-doping narrows bandgap and extends photoresponse to the visible region.
► Degradation of RhB is greatly improved when Flu or EO as sensitizer was introduced.
► The synergetic degradation mechanism was discussed.