Optimization of hydrolysis temperature in liquid phase deposition for TiO2 photocatalysis

TiO2 nanostructure could be produced at below 100 °C by means of liquid phase deposition (LPD), which is a green approach with low cost and low impact on the environment. The improvement of crystallinity is one of the main challenges toward efficient photocatalysis. Herein, we investigated the dependence of synthesis temperature on the crystal structure of TiO2 photocatalysts to provide higher photocatalytic efficiency. Scanning electron microscopy, X-ray diffraction, and Raman spectroscopy analysis confirmed the formation of waxberry-like TiO2 with an anatase phase with a synthetic temperature up to 80 °C. Both reaction temperature and time are found to dictate the crystallinity, structure, and size of the products, which could be attributed to the hydrolysis of a precursor (ammonium hexafluoro titanate), as well as the aggregation and coagulation of primary particles. The product synthesized at 70 °C for 3 h exhibited higher crystallinity, which led to higher photocatalytic efficiency observed based on the decomposition of methylene blue.