Dependence between ionic liquid structure and mechanism of visible-light-induced activity of TiO2
obtained by ionic-liquid-assisted solvothermal synthesis
Marta Paszkiewicz-Gawron , Marta Długokęcka , Wojciech Lisowski , Maria Cristina Paganini , Elio Giamello , Tomasz Klimczuk , Monika Paszkiewicz , Ewelina Grabowska , Adriana Zaleska-Medynska , Justyna Łuczak
AbstractBecause of the tremendous structural diversity of ionic liquids (ILs), simple transfer of observations performed for one IL used for IL-TiO2 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-TiO2 composites. The role of the individual IL cation in the synthesis of TiO2 microspheres, as well as the effect of the IL structure on the mechanism of the visible-light (Vis)-induced photoactivity of IL-TiO2 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 TiO2 with organic IL species including possible interactions between IL and TiO2 surface, as well as the TiO2 matrix (doping with N), were confirmed. The sample that exhibited the highest photoactivity under Vis irradiation (58%) was TiO2 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 TiO2 (Ti-Nx) as well as the highest surface defects in a form of Ti3+. The superoxide radical species O2• – were found to be main active species responsible for high efficiency of degradation under Vis irradiation.
|Journal series||ACS Sustainable Chemistry & Engineering, ISSN 2168-0485|
|Keywords in English||ionic liquid, photocatalysis, titanium dioxide, visible light activity, surface interactions, N-doping|
|Score|| = 40.0, 20-06-2018, ArticleFromJournal|
= 40.0, 20-06-2018, ArticleFromJournal
|Publication indicators||: 2016 = 5.951 (2) - 2016=6.079 (5)|
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