1 research outputs found
Dependence between Ionic Liquid Structure and Mechanism of Visible-Light-Induced Activity of TiO<sub>2</sub> Obtained by Ionic-Liquid-Assisted Solvothermal Synthesis
Because
of the tremendous structural diversity of ionic liquids
(ILs), simple transfer of observations performed for one IL used for
IL-TiO<sub>2</sub> preparation on different samples is not possible.
Therefore, four ionic liquids, all containing distinct nitrogen-bearing
organic cations (pyridinium, pyrrolidinium, ammonium, imidazolium),
were used for the first time for the preparation of IL-TiO<sub>2</sub> composites. The role of the individual IL cation in the synthesis
of TiO<sub>2</sub> microspheres, as well as the effect of the IL structure
on the mechanism of the visible-light (Vis)-induced photoactivity
of IL-TiO<sub>2</sub> was presented and discussed in regard to structure,
morphology, absorption properties, elemental composition, and reactive
species involved in the photocatalytic reaction of phenol degradation.
The successful modification of the TiO<sub>2</sub> with organic IL
species including possible interactions between IL and TiO<sub>2</sub> surface, as well as the TiO<sub>2</sub> matrix (doping with N),
were confirmed. The sample that exhibited the highest photoactivity
under Vis irradiation (58%) was TiO<sub>2</sub> prepared in a presence
of 1-butylpyridinium chloride with a IL:precursor molar ratio of 1:3.
For this sample, the highest partial decomposition of cationic species
of IL was observed resulting in interaction of N atoms with deeper
sites of TiO<sub>2</sub> (Ti-N<sub><i>x</i></sub>) as well
as the highest surface defects in a form of Ti<sup>3+</sup>. The superoxide
radical species O<sub>2</sub><sup>• –</sup> were
found to be main active species responsible for high efficiency of
degradation under Vis irradiation