Enhancing the photocatalytic activity of nanocrystalline TiO2 by co-doping with fluorine and yttrium

•(F, Y)-codoped TiO2 nanoparticles were prepared by a simple sol–gel method.•The highest photocatalytic activity (15 times of that over the pure TiO2) was exhibited in the codoped TiO2 with 0.05% Y doping level.•The Y doping induced oxygen vancancies played a duel role on the photocatalyic activity of the codoped TiO2.•The photocatalytic reactive oxygen species are critical to the photocatalytic degradation processes.

Fluorine and yttrium codoped TiO2 nanoparticles were prepared using a simple sol–gel method. The products were characterized with various spectroscopic and analytical techniques to determine their structural, morphological, optical absorption and photocatalytic properties. The results reveal that neither F nor Y doping causes obvious absorption edge shift in TiO2. Photoluminescence (PL) emission spectra present that the PL signal is enhanced, suggesting a decrease of photo-generated charge carrier separation efficiency, after the F or Y doping. The synergistic action by the F and Y doping leads to the highest photocatalytic activity for the degradation of methylene blue solution in the 0.05% (F, Y)-codoped sample (15 times of that over the pure TiO2). With the increase of Y doping level, the photocatalytic performance in the codoped samples increases firstly and then decreases. The photocatalytic activity variations after the F and Y doping were interpreted by the formation of photocatalytic reactive oxygen species induced by the dopings.

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