Effect of π–π stacking of water miscible ionic liquid template with different cation chain length and content on morphology of mesoporous TiO2 prepared via sol–gel method and the applications

In this study, the imidazolium π–π stacking of two water miscible imidazolium ionic liquids (ILs) in the TiO2 matrix formed during the sol–gel polymerization was studied by FT-IR, XRD, TEM and BET measurements. It was found that the mesoporous morphology, including surface area, average pore size and wormhole-like structure, and thermal stability of the as-prepared TiO2 particle were varied with the imidazolium chain length and content of the IL used due to different extent of imidazolium π–π stacking. Besides, the wormhole-like mesoporous anatase TiO2 particles with high surface area exhibited higher photodegradation efficiencies of methylene blue (MB) under 1 h UV irradiation, while those with large pore size used for the electrode materials showed higher efficiency in dye-sensitized solar cells.