Preparation of Nanocrystalline GdFeO₃ by Microwave Method and Its Visible-light Photocatalytic Activity

The nanocrystalline perovskite GdFeO3 was synthesized using Gd(NO3)3·6H2O and Fe(NO3)3·9H2O by a facile microwave method. The prepared samples were characterized by thermogravimetry and differential thermal analysis (TG-DTA), powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV-visible diffuse reflectance spectroscopy (DRS). XRD and SEM demonstrate the successful synthesis of single phase perovskite GdFeO3 and an average grain size of 80 nm in diameter. DRS shows the optical absorption onset of 600 nm, indicating the optical band gap of 2.1 eV. The photocatalytic activity of nanocrystalline GdFeO3 which was calcined at different temperature was investigated in experimental simulation wastewater containing 10 mg/L methyl orange (MO). The results show that the nanocrystalline GdFeO3 appears the high photocatalytic activity for the decomposition of MO under visible-light irradiation, but photocatalytic activity gradually decreases with the calcination temperature decreasing.