Titanium Dioxide Nanosheets derived from Indonesian Ilmenite Mineral through Post-Hydrothermal Process

Titanium dioxide (TiO_2) nanosheets are potential candidate material to be developed for photocatalytic applications. The natural resources of TiO_2 are abundant in the form of the mineral ilmenite (FeTiO_3). In this work, TiO_2 nanosheets have been synthesized using ilmenite mineral as the precursor through a post-hydrothermal process with temperature variations of 80,100, 120, and 150oC for 24 hours. The resulting TiO_2 nanosheets were characterized by x-ray diffraction (XRD), scanning electron microscope (SEM) and ultraviolet visible-diffuse reflectance spectroscopy (UV-DRS). XRD analysis showed that the majority phase of the nanosheets was anatase TiO_2 accompanied by a small amount of sodium-titanate. The SEM study reveals the average thickness of nanosheets derived from post-hydrothermal process was 24.86 nm. XRD test results also showed that the increase in post-hydrothermal temperature from 80 to 150oC has resulted in an increase in the crystallite size of anatase TiO_2 from 35.14 to 45.59 nm. Such increase in the crystallite size has been found to lead to a decrease in the bandgap energy (Eg) of nanosheets from 2.85 to 2.70 eV. These results support the potential use of the resulting TiO_2 nanosheets as the photocatalytic material under the visible light illumination