TiOF2/TiO2 composite nanosheets: Effect of hydrothermal synthesis temperature on physicochemical properties and photocatalytic activity

TiOF2/TiO2 nanosheets were prepared by hydrothermal processing of Ti(OBu)4 in the presence of aqueous HF solution. The effect of different hydrothermal synthesis temperatures (140, 160, 180, and 200 °C) on the compositions, morphologies, crystal sizes, and photoelectric properties of the resulting samples was studied via various characterization methods. The photocatalytic properties of the samples were studied through photodegradation of organic pollutants such as rhodamine B (RhB), methyl orange (MO), and ciprofloxacin hydrochloride (CIP-HCl). TiOF2/TiO2 nanosheets prepared by hydrothermal synthesis at 160 °C exhibited the highest photocatalytic activity among these samples, and it is much more active than P25 (a benchmark photocatalyst) and TiO2 prepared hydrothermally (without adding aqueous HF solution during the hydrothermal synthesis). A possible photocatalytic mechanism is discussed.