Preparation of Tm2Ti2O7 by Sol-Gel Method and Its Photocatalytic Activity.

Using citric acid (C6H8O7·H2O), thulium oxide (Tm2O3), nitric acid (HNO3), tetrabutyl titanate (C16H36O4Ti) as main raw materials, the Tm2Ti2O7 samples were successfully prepared by sol-gel method. The prepared samples were characterized by the thermogravimetry and differential scanning calorimetry (TG-DSC), X-ray diffractometer (XRD), scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FT-IR). Using 50 mg/L azo dye methyl orange solution as the simulated sewage, the photocatalytic activity of Tm2Ti2O7 samples was investigated at different calcination temperatures and illumination times. The experimental results show that pure Tm2Ti2O7 samples can be prepared at a calcination temperature of 750–1000 °C. According to SEM analysis, Tm2Ti2O7 samples is irregular, with an average particle size of approximately 10 μm. The degradation rate of methyl orange of each sample calcined at 750–1000 °C temperature range can reach more than 50% when exposed to ultraviolet light for 30 min, and the sample calcined at 900 °C has the best photocatalytic effect. When it degrades 50 mg/L methyl orange for 90 min, the degradation rate can almost reach 100%, and the degradation kinetic constant is 0.0488 min−1, which conforms to the first-order kinetics. The above conclusions indicate that Tm2Ti2O7 is a novel photocatalyst with broad application prospects in the field of ultraviolet photocatalysis. [ABSTRACT FROM AUTHOR]