Structural characterization of nanocrystalline TiO2 from ionic liquid-water solvent mixture and its photocatalytic activity

Nanocrystalline TiO2 was synthesized by the low-temperature hydrothermal method using ionic liquid (1-ethyl-3-methyl-imidazole acetate)-water mixture as solvent; various studies such as X-ray diffraction, Brunauer-Emmett-Teller surface area, X-ray photoelectron spectra, UV-Vis spectroscopy were conducted. The products prepared from ionic liquid-water mixture possessed good anatase crystallinity and contained less brookite phase than that from pure water. The photocatalytic degradation of methyl orange in water was studied in photoreactor with UV lamp as light source. The product prepared from ionic liquid-water solvent for 24 h showed superior photocatalytic activity for the degradation of methyl orange compared to commercial TiO2, Degussa P25. The higher photocatalytic activity was attributed to the crystal phase, grain size, and specific surface area of the catalyst. Further, the effects of the catalyst amount and pH value of solution on the photocatalytic activity of the product were also investigated.