Characterization and Photocatalytic Activity of SmMnO<sub>3</sub> Prepared by Sol-Gel Process

Using samarium (III) nitrate hexahydrate, manganese nitrate and citric acid as main raw materials, the SmMnO 3 gel was prepared by sol-gel process. The gel was kept at 100 °C for 24 h to get the xerogel. Then, the xerogel was respectively calcined in muffle furnace at 600 °C, 700 °C, 800 °C and 900 °C. The structure and morphology of samples were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier Transform Infrared (FT-IR) spectroscopy. The UV photocatalytic activities of SmMnO 3 were investigated by methyl orange which was used as simulated sewage. The results show that the pure SmMnO 3 can be obtained through calcination between 700 °C and 800 °C, and the SmMnO 3 have an average particle size of 80 nm. The SmMnO 3 samples calcined at 700 °C and 800 °C show high photocatalytic activity for decomposition of methyl orange under UV-light irradiation. The SmMnO 3 samples are consistent with first-order kinetics for the degradation of methyl orange. And the apparent rate constants are respectively k 70 0 =0.01206 min -1 and k 800 =0.01088 min -1 .