Synthesis and characterization of calcium-doped lanthanum manganite nanowires as a photocatalyst for degradation of methylene blue solution under visible light irradiation

摘要

Calcium-doped lanthanum manganite (LCMO) powder was synthesized via hydrothermal method. The structural, morphological and optical properties of the resulting powder was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), inductively coupled plasma-atomic emission spectroscopy (ICP-AES spectrometer), field emission scanning electron microscopy (FESEM) and UV-Vis spectroscopy (UV-Vis). The XRD results showed the existence of only one crystalline phase. FESEM image indicates that the LCMO sample has nanowire structure with an average diameter of similar to 125 nm. The band gap energy of the sample was about 2.13 eV. The as-prepared nanowires showed sufficient visible-light photocatalytic activity for the water treatment from dyes and toxic organic materials. The photodegradation efficiency for decolourizing methylene blue solution (7 ppm) by LCMO nanowires (0.07g l(-1)) , after 360 min illumination, was about 73% with a reaction rate constant of 0.003 min(-1) . The six times cycled results suggested the great long-term stability of the photocatalyst.