Fabrication of Dy2Ti2O7 nanocrystalline at 700 °C and its photocatalytic activity

Dy2Ti2O7 nanocrystalline was fabricated by a soft-chemistry route named as citric acid sol–gel method (CAM). The fabricating process was monitored by XRD, FT-IR and TG-DTA methods. It was found that compared with traditional solid state reaction (SSR), Dy2Ti2O7 was synthesized at a relatively low temperature (700 °C) and with shortened reaction time (2 h). The morphology and surface composition of obtained products were determined by TEM and SEM-EDX experiments. Results showed that the obtained Dy2Ti2O7 with good dispersibility were all square-like; the average size was about 50 nm and there was ample oxygen-deficient (40%) on the product interfaces. Also, the obtained products had higher BET surface area (25.10 m2/g). These properties are very helpful for a catalyst to achieve excellent photocatalytic activity. Photodecomposition of methyl orange was used as the model system to evaluate its photocatalytic property. It was found that Dy2Ti2O7 showed good photocatalytic activity and the decomposition rate of methyl orange was about 99% within 60 min.